Release 2022.10.0

TUN-6813: Only proxy ICMP packets when warp-routing is enabled
TUN-6812: Drop IP packets if ICMP proxy is not initialized
2026-06-08 13:33:07 +00:00 · 2022-10-03 09:55:15 +01:00 · 2022-09-30 19:08:12 +01:00 · 2022-09-30 14:10:32 +00:00 · 2022-09-30 10:28:28 +01:00 · 2022-09-29 09:22:43 -07:00
91 changed files with 5207 additions and 1027 deletions
@@ -23,4 +23,4 @@ git config --global user.name "cloudflare-warp-bot"
 git config --global user.email "warp-bot@cloudflare.com"

 # bump formula pr
-brew bump-formula-pr cloudflared --version="$VERSION" --no-browse
+brew bump-formula-pr cloudflared --version="$VERSION" --no-browse --no-audit
@@ -145,22 +145,6 @@ endif
 test-ssh-server:
 	docker-compose -f ssh_server_tests/docker-compose.yml up

-define publish_package
-	chmod 664 $(BINARY_NAME)*.$(1); \
-	for HOST in $(CF_PKG_HOSTS); do \
-		ssh-keyscan -t ecdsa $$HOST >> ~/.ssh/known_hosts; \
-		scp -p -4 $(BINARY_NAME)*.$(1) cfsync@$$HOST:/state/cf-pkg/staging/$(2)/$(TARGET_PUBLIC_REPO)/$(BINARY_NAME)/; \
-	done
-endef
-
-.PHONY: publish-deb
-publish-deb: cloudflared-deb
-	$(call publish_package,deb,apt)
-
-.PHONY: publish-rpm
-publish-rpm: cloudflared-rpm
-	$(call publish_package,rpm,yum)
-
 cloudflared.1: cloudflared_man_template
 	cat cloudflared_man_template | sed -e 's/\$${VERSION}/$(VERSION)/; s/\$${DATE}/$(DATE)/' > cloudflared.1

@@ -1,3 +1,21 @@
+2022.10.0
+- 2022-09-30 TUN-6755: Remove unused publish functions
+- 2022-09-30 TUN-6813: Only proxy ICMP packets when warp-routing is enabled
+- 2022-09-29 TUN-6811: Ping group range should be parsed as int32
+- 2022-09-29 TUN-6812: Drop IP packets if ICMP proxy is not initialized
+- 2022-09-28 TUN-6716: Document limitation of Windows ICMP proxy
+- 2022-09-28 TUN-6810: Add component test for post-quantum
+- 2022-09-27 TUN-6715: Provide suggestion to add cloudflared to ping_group_range if it failed to open ICMP socket
+- 2022-09-22 TUN-6792: Fix brew core release by not auditing the formula
+- 2022-09-22 TUN-6774: Validate OriginRequest.Access to add Ingress.Middleware
+- 2022-09-22 TUN-6775: Add middleware.Handler verification to ProxyHTTP
+- 2022-09-22 TUN-6791: Calculate ICMPv6 checksum
+- 2022-09-22 TUN-6801: Add punycode alternatives for ingress rules
+- 2022-09-21 TUN-6772: Add a JWT Validator as an ingress verifier
+- 2022-09-21 TUN-6772: Add a JWT Validator as an ingress verifier
+- 2022-09-21 TUN-6774: Validate OriginRequest.Access to add Ingress.Middleware
+- 2022-09-21 TUN-6772: Add a JWT Validator as an ingress verifier
+- 2022-09-20 TUN-6741: ICMP proxy tries to listen on specific IPv4 & IPv6 when possible
 2022.9.1
 - 2022-09-20 TUN-6777: Fix race condition in TestFunnelIdleTimeout
 - 2022-09-20 TUN-6595: Enable datagramv2 and icmp proxy by default
@@ -119,18 +119,6 @@ stretch: &stretch
      - export GOOS=linux
      - export GOARCH=arm64
      - make cloudflared-deb
-  publish-deb:
-    build_dir: *build_dir
-    builddeps:
-      - *pinned_go
-      - build-essential
-      - fakeroot
-      - rubygem-fpm
-      - openssh-client
-    post-cache:
-      - export GOOS=linux
-      - export GOARCH=amd64
-      - make publish-deb
  github-release-macos-amd64:
    build_dir: *build_dir
    builddeps: &build_pygithub
@@ -195,6 +183,26 @@ stretch: &stretch
      - ./fmt-check.sh
      - make test | gotest-to-teamcity
  component-test:
+    build_dir: *build_dir
+    builddeps:
+      - *pinned_go
+      - python3.7
+      - python3-pip
+      - python3-setuptools
+      # procps installs the ps command which is needed in test_sysv_service because the init script
+      # uses ps pid to determine if the agent is running
+      - procps
+    pre-cache-copy-paths:
+      - component-tests/requirements.txt
+    pre-cache: &component_test_pre_cache
+      - sudo pip3 install --upgrade -r component-tests/requirements.txt
+    post-cache: &component_test_post_cache
+      # Creates and routes a Named Tunnel for this build. Also constructs config file from env vars.
+      - python3 component-tests/setup.py --type create
+      - pytest component-tests -o log_cli=true --log-cli-level=INFO
+      # The Named Tunnel is deleted and its route unprovisioned here.
+      - python3 component-tests/setup.py --type cleanup
+  component-test-fips:
    build_dir: *build_dir
    builddeps:
      - *pinned_go_fips
@@ -206,20 +214,15 @@ stretch: &stretch
      - procps
    pre-cache-copy-paths:
      - component-tests/requirements.txt
-    pre-cache:
-      - sudo pip3 install --upgrade -r component-tests/requirements.txt
-    post-cache:
-      # Creates and routes a Named Tunnel for this build. Also constructs config file from env vars.
-      - python3 component-tests/setup.py --type create
-      - pytest component-tests -o log_cli=true --log-cli-level=INFO
-      # The Named Tunnel is deleted and its route unprovisioned here.
-      - python3 component-tests/setup.py --type cleanup
+    pre-cache: *component_test_pre_cache
+    post-cache: *component_test_post_cache
  update-homebrew:
    builddeps:
      - openssh-client
      - s3cmd
      - jq
      - build-essential
+      - procps
    post-cache:
      - .teamcity/update-homebrew.sh
      - .teamcity/update-homebrew-core.sh
@@ -262,18 +265,3 @@ stretch: &stretch
 buster: *stretch
 bullseye: *stretch
 bookworm: *stretch
-centos-7:
-  publish-rpm:
-    build_dir: *build_dir
-    builddeps: &el7_builddeps
-      - https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
-    pre-cache:
-      - yum install -y fakeroot
-      - yum upgrade -y binutils-2.27-44.base.el7.x86_64
-      - wget https://go.dev/dl/go1.18.6.linux-amd64.tar.gz -P /tmp/
-      - tar -C /usr/local -xzf /tmp/go1.18.6.linux-amd64.tar.gz
-    post-cache:
-      - export PATH=$PATH:/usr/local/go/bin
-      - export GOOS=linux
-      - export GOARCH=amd64
-      - make publish-rpm
@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"io/ioutil"
 	mathRand "math/rand"
+	"net"
+	"net/netip"
 	"os"
 	"path/filepath"
 	"strings"
@@ -20,6 +22,7 @@ import (

 	"github.com/cloudflare/cloudflared/cmd/cloudflared/cliutil"
 	"github.com/cloudflare/cloudflared/edgediscovery/allregions"
+	"github.com/cloudflare/cloudflared/packet"

 	"github.com/cloudflare/cloudflared/config"
 	"github.com/cloudflare/cloudflared/connection"
@@ -384,6 +387,12 @@ func prepareTunnelConfig(
 		NeedPQ:           needPQ,
 		PQKexIdx:         pqKexIdx,
 	}
+	packetConfig, err := newPacketConfig(c, log)
+	if err != nil {
+		log.Warn().Err(err).Msg("ICMP proxy feature is disabled")
+	} else {
+		tunnelConfig.PacketConfig = packetConfig
+	}
 	orchestratorConfig := &orchestration.Config{
 		Ingress:            &ingressRules,
 		WarpRouting:        ingress.NewWarpRoutingConfig(&cfg.WarpRouting),
@@ -453,3 +462,147 @@ func parseConfigIPVersion(version string) (v allregions.ConfigIPVersion, err err
 	}
 	return
 }
+
+func newPacketConfig(c *cli.Context, logger *zerolog.Logger) (*packet.GlobalRouterConfig, error) {
+	ipv4Src, err := determineICMPv4Src(c.String("icmpv4-src"), logger)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to determine IPv4 source address for ICMP proxy")
+	}
+	logger.Info().Msgf("ICMP proxy will use %s as source for IPv4", ipv4Src)
+
+	ipv6Src, zone, err := determineICMPv6Src(c.String("icmpv6-src"), logger, ipv4Src)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to determine IPv6 source address for ICMP proxy")
+	}
+	if zone != "" {
+		logger.Info().Msgf("ICMP proxy will use %s in zone %s as source for IPv6", ipv6Src, zone)
+	} else {
+		logger.Info().Msgf("ICMP proxy will use %s as source for IPv6", ipv6Src)
+	}
+
+	icmpRouter, err := ingress.NewICMPRouter(ipv4Src, ipv6Src, zone, logger)
+	if err != nil {
+		return nil, err
+	}
+	return &packet.GlobalRouterConfig{
+		ICMPRouter: icmpRouter,
+		IPv4Src:    ipv4Src,
+		IPv6Src:    ipv6Src,
+		Zone:       zone,
+	}, nil
+}
+
+func determineICMPv4Src(userDefinedSrc string, logger *zerolog.Logger) (netip.Addr, error) {
+	if userDefinedSrc != "" {
+		addr, err := netip.ParseAddr(userDefinedSrc)
+		if err != nil {
+			return netip.Addr{}, err
+		}
+		if addr.Is4() {
+			return addr, nil
+		}
+		return netip.Addr{}, fmt.Errorf("expect IPv4, but %s is IPv6", userDefinedSrc)
+	}
+
+	addr, err := findLocalAddr(net.ParseIP("192.168.0.1"), 53)
+	if err != nil {
+		addr = netip.IPv4Unspecified()
+		logger.Debug().Err(err).Msgf("Failed to determine the IPv4 for this machine. It will use %s to send/listen for ICMPv4 echo", addr)
+	}
+	return addr, nil
+}
+
+type interfaceIP struct {
+	name string
+	ip   net.IP
+}
+
+func determineICMPv6Src(userDefinedSrc string, logger *zerolog.Logger, ipv4Src netip.Addr) (addr netip.Addr, zone string, err error) {
+	if userDefinedSrc != "" {
+		userDefinedIP, zone, _ := strings.Cut(userDefinedSrc, "%")
+		addr, err := netip.ParseAddr(userDefinedIP)
+		if err != nil {
+			return netip.Addr{}, "", err
+		}
+		if addr.Is6() {
+			return addr, zone, nil
+		}
+		return netip.Addr{}, "", fmt.Errorf("expect IPv6, but %s is IPv4", userDefinedSrc)
+	}
+
+	// Loop through all the interfaces, the preference is
+	// 1. The interface where ipv4Src is in
+	// 2. Interface with IPv6 address
+	// 3. Unspecified interface
+
+	interfaces, err := net.Interfaces()
+	if err != nil {
+		return netip.IPv6Unspecified(), "", nil
+	}
+
+	interfacesWithIPv6 := make([]interfaceIP, 0)
+	for _, interf := range interfaces {
+		interfaceAddrs, err := interf.Addrs()
+		if err != nil {
+			continue
+		}
+
+		foundIPv4SrcInterface := false
+		for _, interfaceAddr := range interfaceAddrs {
+			if ipnet, ok := interfaceAddr.(*net.IPNet); ok {
+				ip := ipnet.IP
+				if ip.Equal(ipv4Src.AsSlice()) {
+					foundIPv4SrcInterface = true
+				}
+				if ip.To4() == nil {
+					interfacesWithIPv6 = append(interfacesWithIPv6, interfaceIP{
+						name: interf.Name,
+						ip:   ip,
+					})
+				}
+			}
+		}
+		// Found the interface of ipv4Src. Loop through the addresses to see if there is an IPv6
+		if foundIPv4SrcInterface {
+			for _, interfaceAddr := range interfaceAddrs {
+				if ipnet, ok := interfaceAddr.(*net.IPNet); ok {
+					ip := ipnet.IP
+					if ip.To4() == nil {
+						addr, err := netip.ParseAddr(ip.String())
+						if err == nil {
+							return addr, interf.Name, nil
+						}
+					}
+				}
+			}
+		}
+	}
+
+	for _, interf := range interfacesWithIPv6 {
+		addr, err := netip.ParseAddr(interf.ip.String())
+		if err == nil {
+			return addr, interf.name, nil
+		}
+	}
+	logger.Debug().Err(err).Msgf("Failed to determine the IPv6 for this machine. It will use %s to send/listen for ICMPv6 echo", netip.IPv6Unspecified())
+
+	return netip.IPv6Unspecified(), "", nil
+}
+
+// FindLocalAddr tries to dial UDP and returns the local address picked by the OS
+func findLocalAddr(dst net.IP, port int) (netip.Addr, error) {
+	udpConn, err := net.DialUDP("udp", nil, &net.UDPAddr{
+		IP:   dst,
+		Port: port,
+	})
+	if err != nil {
+		return netip.Addr{}, err
+	}
+	defer udpConn.Close()
+	localAddrPort, err := netip.ParseAddrPort(udpConn.LocalAddr().String())
+	if err != nil {
+		return netip.Addr{}, err
+	}
+	localAddr := localAddrPort.Addr()
+	return localAddr, nil
+}
@@ -176,6 +176,16 @@ var (
 		Usage:   "Base64 encoded secret to set for the tunnel. The decoded secret must be at least 32 bytes long. If not specified, a random 32-byte secret will be generated.",
 		EnvVars: []string{"TUNNEL_CREATE_SECRET"},
 	}
+	icmpv4SrcFlag = &cli.StringFlag{
+		Name:    "icmpv4-src",
+		Usage:   "Source address to send/receive ICMPv4 messages. If not provided cloudflared will dial a local address to determine the source IP or fallback to 0.0.0.0.",
+		EnvVars: []string{"TUNNEL_ICMPV4_SRC"},
+	}
+	icmpv6SrcFlag = &cli.StringFlag{
+		Name:    "icmpv6-src",
+		Usage:   "Source address and the interface name to send/receive ICMPv6 messages. If not provided cloudflared will dial a local address to determine the source IP or fallback to ::.",
+		EnvVars: []string{"TUNNEL_ICMPV6_SRC"},
+	}
 )

 func buildCreateCommand() *cli.Command {
@@ -613,6 +623,8 @@ func buildRunCommand() *cli.Command {
 		selectProtocolFlag,
 		featuresFlag,
 		tunnelTokenFlag,
+		icmpv4SrcFlag,
+		icmpv6SrcFlag,
 	}
 	flags = append(flags, configureProxyFlags(false)...)
 	return &cli.Command{
@@ -1,6 +1,7 @@
 METRICS_PORT = 51000
 MAX_RETRIES = 5
 BACKOFF_SECS = 7
+MAX_LOG_LINES = 50

 PROXY_DNS_PORT = 9053

@@ -2,6 +2,7 @@
 import json
 import os

+from constants import MAX_LOG_LINES
 from util import start_cloudflared, wait_tunnel_ready, send_requests

 # Rolling logger rotate log files after 1 MB
@@ -11,14 +12,24 @@ expect_message = "Starting Hello"


 def assert_log_to_terminal(cloudflared):
-    stderr = cloudflared.stderr.read(1500)
-    assert expect_message.encode() in stderr, f"{stderr} doesn't contain {expect_message}"
+    for _ in range(0, MAX_LOG_LINES):
+        line = cloudflared.stderr.readline()
+        if not line:
+            break
+        if expect_message.encode() in line:
+            return
+    raise Exception(f"terminal log doesn't contain {expect_message}")


 def assert_log_in_file(file):
    with open(file, "r") as f:
-        log = f.read(2000)
-        assert expect_message in log, f"{log} doesn't contain {expect_message}"
+        for _ in range(0, MAX_LOG_LINES):
+            line = f.readline()
+            if not line:
+                break
+            if expect_message in line:
+                return
+    raise Exception(f"log file doesn't contain {expect_message}")


 def assert_json_log(file):
@@ -0,0 +1,17 @@
+from util import LOGGER, nofips, start_cloudflared, wait_tunnel_ready
+
+
+@nofips
+class TestPostQuantum:
+    def _extra_config(self):
+        config = {
+            "protocol": "quic",
+        }
+        return config
+
+    def test_post_quantum(self, tmp_path, component_tests_config):
+        config = component_tests_config(self._extra_config())
+        LOGGER.debug(config)
+        with start_cloudflared(tmp_path, config, cfd_args=["run", "--post-quantum"], new_process=True):
+            wait_tunnel_ready(tunnel_url=config.get_url(),
+                              require_min_connections=4)
@@ -20,6 +20,12 @@ def select_platform(plat):
    return pytest.mark.skipif(
        platform.system() != plat, reason=f"Only runs on {plat}")

+def fips_enabled():
+    env_fips = os.getenv("COMPONENT_TESTS_FIPS")
+    return env_fips is not None and env_fips != "0"
+
+nofips = pytest.mark.skipif(
+        fips_enabled(), reason=f"Only runs without FIPS (COMPONENT_TESTS_FIPS=0)")

 def write_config(directory, config):
    config_path = directory / "config.yml"
@@ -234,14 +234,14 @@ type OriginRequestConfig struct {
 }

 type AccessConfig struct {
-	// Enabled when set to true will fail every request that does not arrive through an access authenticated endpoint.
-	Enabled bool
+	// Required when set to true will fail every request that does not arrive through an access authenticated endpoint.
+	Required bool `yaml:"required" json:"required,omitempty"`

 	// TeamName is the organization team name to get the public key certificates for.
-	TeamName string `yaml:"teamName" json:"teamName,omitempty"`
+	TeamName string `yaml:"teamName" json:"teamName"`

 	// AudTag is the AudTag to verify access JWT against.
-	AudTag []string `yaml:"audTag" json:"audTag,omitempty"`
+	AudTag []string `yaml:"audTag" json:"audTag"`
 }

 type IngressIPRule struct {
@@ -39,6 +39,7 @@ type Orchestrator interface {
 	UpdateConfig(version int32, config []byte) *pogs.UpdateConfigurationResponse
 	GetConfigJSON() ([]byte, error)
 	GetOriginProxy() (OriginProxy, error)
+	WarpRoutingEnabled() (enabled bool)
 }

 type NamedTunnelProperties struct {
@@ -56,6 +56,10 @@ func (mcr *mockOrchestrator) GetOriginProxy() (OriginProxy, error) {
 	return mcr.originProxy, nil
 }

+func (mcr *mockOrchestrator) WarpRoutingEnabled() (enabled bool) {
+	return true
+}
+
 type mockOriginProxy struct{}

 func (moc *mockOriginProxy) ProxyHTTP(
@@ -50,7 +50,7 @@ type QUICConnection struct {
 	// sessionManager tracks active sessions. It receives datagrams from quic connection via datagramMuxer
 	sessionManager datagramsession.Manager
 	// datagramMuxer mux/demux datagrams from quic connection
-	datagramMuxer        quicpogs.BaseDatagramMuxer
+	datagramMuxer        *quicpogs.DatagramMuxerV2
 	packetRouter         *packet.Router
 	controlStreamHandler ControlStreamHandler
 	connOptions          *tunnelpogs.ConnectionOptions
@@ -65,7 +65,7 @@ func NewQUICConnection(
 	connOptions *tunnelpogs.ConnectionOptions,
 	controlStreamHandler ControlStreamHandler,
 	logger *zerolog.Logger,
-	icmpRouter packet.ICMPRouter,
+	packetRouterConfig *packet.GlobalRouterConfig,
 ) (*QUICConnection, error) {
 	session, err := quic.DialAddr(edgeAddr.String(), tlsConfig, quicConfig)
 	if err != nil {
@@ -73,18 +73,9 @@ func NewQUICConnection(
 	}

 	sessionDemuxChan := make(chan *packet.Session, demuxChanCapacity)
-	var (
-		datagramMuxer quicpogs.BaseDatagramMuxer
-		pr            *packet.Router
-	)
-	if icmpRouter != nil {
-		datagramMuxerV2 := quicpogs.NewDatagramMuxerV2(session, logger, sessionDemuxChan)
-		pr = packet.NewRouter(datagramMuxerV2, &returnPipe{muxer: datagramMuxerV2}, icmpRouter, logger)
-		datagramMuxer = datagramMuxerV2
-	} else {
-		datagramMuxer = quicpogs.NewDatagramMuxer(session, logger, sessionDemuxChan)
-	}
+	datagramMuxer := quicpogs.NewDatagramMuxerV2(session, logger, sessionDemuxChan)
 	sessionManager := datagramsession.NewManager(logger, datagramMuxer.SendToSession, sessionDemuxChan)
+	packetRouter := packet.NewRouter(packetRouterConfig, datagramMuxer, &returnPipe{muxer: datagramMuxer}, logger, orchestrator.WarpRoutingEnabled)

 	return &QUICConnection{
 		session:              session,
@@ -92,7 +83,7 @@ func NewQUICConnection(
 		logger:               logger,
 		sessionManager:       sessionManager,
 		datagramMuxer:        datagramMuxer,
-		packetRouter:         pr,
+		packetRouter:         packetRouter,
 		controlStreamHandler: controlStreamHandler,
 		connOptions:          connOptions,
 	}, nil
@@ -128,17 +119,14 @@ func (q *QUICConnection) Serve(ctx context.Context) error {
 		defer cancel()
 		return q.sessionManager.Serve(ctx)
 	})
-
 	errGroup.Go(func() error {
 		defer cancel()
 		return q.datagramMuxer.ServeReceive(ctx)
 	})
-	if q.packetRouter != nil {
-		errGroup.Go(func() error {
-			defer cancel()
-			return q.packetRouter.Serve(ctx)
-		})
-	}
+	errGroup.Go(func() error {
+		defer cancel()
+		return q.packetRouter.Serve(ctx)
+	})

 	return errGroup.Wait()
 }
@@ -583,8 +583,12 @@ func serveSession(ctx context.Context, qc *QUICConnection, edgeQUICSession quic.
 		close(sessionDone)
 	}()

-	// Send a message to the quic session on edge side, it should be deumx to this datagram session
-	muxedPayload := append(payload, sessionID[:]...)
+	// Send a message to the quic session on edge side, it should be deumx to this datagram v2 session
+	muxedPayload, err := quicpogs.SuffixSessionID(sessionID, payload)
+	require.NoError(t, err)
+	muxedPayload, err = quicpogs.SuffixType(muxedPayload, quicpogs.DatagramTypeUDP)
+	require.NoError(t, err)
+
 	err = edgeQUICSession.SendMessage(muxedPayload)
 	require.NoError(t, err)

@@ -36,7 +36,7 @@ require (
 	go.uber.org/automaxprocs v1.4.0
 	golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa
 	golang.org/x/net v0.0.0-20220909164309-bea034e7d591
-	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
+	golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f
 	golang.org/x/sys v0.0.0-20220808155132-1c4a2a72c664
 	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211
 	google.golang.org/protobuf v1.28.0
@@ -56,6 +56,7 @@ require (
 	github.com/cheekybits/genny v1.0.0 // indirect
 	github.com/cloudflare/circl v1.2.1-0.20220809205628-0a9554f37a47 // indirect
 	github.com/coredns/caddy v1.1.1 // indirect
+	github.com/coreos/go-oidc/v3 v3.4.0 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/facebookgo/ensure v0.0.0-20160127193407-b4ab57deab51 // indirect
@@ -89,13 +90,13 @@ require (
 	github.com/prometheus/procfs v0.7.3 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	golang.org/x/mod v0.4.2 // indirect
-	golang.org/x/oauth2 v0.0.0-20211104180415-d3ed0bb246c8 // indirect
+	golang.org/x/oauth2 v0.0.0-20220822191816-0ebed06d0094 // indirect
 	golang.org/x/text v0.3.7 // indirect
 	golang.org/x/tools v0.1.6-0.20210726203631-07bc1bf47fb2 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f // indirect
 	google.golang.org/appengine v1.6.7 // indirect
-	google.golang.org/genproto v0.0.0-20211223182754-3ac035c7e7cb // indirect
-	google.golang.org/grpc v1.45.0 // indirect
+	google.golang.org/genproto v0.0.0-20220616135557-88e70c0c3a90 // indirect
+	google.golang.org/grpc v1.47.0 // indirect
 	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 )
@@ -28,14 +28,23 @@ cloud.google.com/go v0.93.3/go.mod h1:8utlLll2EF5XMAV15woO4lSbWQlk8rer9aLOfLh7+Y
 cloud.google.com/go v0.94.1/go.mod h1:qAlAugsXlC+JWO+Bke5vCtc9ONxjQT3drlTTnAplMW4=
 cloud.google.com/go v0.97.0/go.mod h1:GF7l59pYBVlXQIBLx3a761cZ41F9bBH3JUlihCt2Udc=
 cloud.google.com/go v0.99.0/go.mod h1:w0Xx2nLzqWJPuozYQX+hFfCSI8WioryfRDzkoI/Y2ZA=
+cloud.google.com/go v0.100.2/go.mod h1:4Xra9TjzAeYHrl5+oeLlzbM2k3mjVhZh4UqTZ//w99A=
+cloud.google.com/go v0.102.0/go.mod h1:oWcCzKlqJ5zgHQt9YsaeTY9KzIvjyy0ArmiBUgpQ+nc=
 cloud.google.com/go/bigquery v1.0.1/go.mod h1:i/xbL2UlR5RvWAURpBYZTtm/cXjCha9lbfbpx4poX+o=
 cloud.google.com/go/bigquery v1.3.0/go.mod h1:PjpwJnslEMmckchkHFfq+HTD2DmtT67aNFKH1/VBDHE=
 cloud.google.com/go/bigquery v1.4.0/go.mod h1:S8dzgnTigyfTmLBfrtrhyYhwRxG72rYxvftPBK2Dvzc=
 cloud.google.com/go/bigquery v1.5.0/go.mod h1:snEHRnqQbz117VIFhE8bmtwIDY80NLUZUMb4Nv6dBIg=
 cloud.google.com/go/bigquery v1.7.0/go.mod h1://okPTzCYNXSlb24MZs83e2Do+h+VXtc4gLoIoXIAPc=
 cloud.google.com/go/bigquery v1.8.0/go.mod h1:J5hqkt3O0uAFnINi6JXValWIb1v0goeZM77hZzJN/fQ=
+cloud.google.com/go/compute v0.1.0/go.mod h1:GAesmwr110a34z04OlxYkATPBEfVhkymfTBXtfbBFow=
+cloud.google.com/go/compute v1.3.0/go.mod h1:cCZiE1NHEtai4wiufUhW8I8S1JKkAnhnQJWM7YD99wM=
+cloud.google.com/go/compute v1.5.0/go.mod h1:9SMHyhJlzhlkJqrPAc839t2BZFTSk6Jdj6mkzQJeu0M=
+cloud.google.com/go/compute v1.6.0/go.mod h1:T29tfhtVbq1wvAPo0E3+7vhgmkOYeXjhFvz/FMzPu0s=
+cloud.google.com/go/compute v1.6.1/go.mod h1:g85FgpzFvNULZ+S8AYq87axRKuf2Kh7deLqV/jJ3thU=
+cloud.google.com/go/compute v1.7.0/go.mod h1:435lt8av5oL9P3fv1OEzSbSUe+ybHXGMPQHHZWZxy9U=
 cloud.google.com/go/datastore v1.0.0/go.mod h1:LXYbyblFSglQ5pkeyhO+Qmw7ukd3C+pD7TKLgZqpHYE=
 cloud.google.com/go/datastore v1.1.0/go.mod h1:umbIZjpQpHh4hmRpGhH4tLFup+FVzqBi1b3c64qFpCk=
+cloud.google.com/go/iam v0.3.0/go.mod h1:XzJPvDayI+9zsASAFO68Hk07u3z+f+JrT2xXNdp4bnY=
 cloud.google.com/go/pubsub v1.0.1/go.mod h1:R0Gpsv3s54REJCy4fxDixWD93lHJMoZTyQ2kNxGRt3I=
 cloud.google.com/go/pubsub v1.1.0/go.mod h1:EwwdRX2sKPjnvnqCa270oGRyludottCI76h+R3AArQw=
 cloud.google.com/go/pubsub v1.2.0/go.mod h1:jhfEVHT8odbXTkndysNHCcx0awwzvfOlguIAii9o8iA=
@@ -45,6 +54,7 @@ cloud.google.com/go/storage v1.5.0/go.mod h1:tpKbwo567HUNpVclU5sGELwQWBDZ8gh0Zeo
 cloud.google.com/go/storage v1.6.0/go.mod h1:N7U0C8pVQ/+NIKOBQyamJIeKQKkZ+mxpohlUTyfDhBk=
 cloud.google.com/go/storage v1.8.0/go.mod h1:Wv1Oy7z6Yz3DshWRJFhqM/UCfaWIRTdp0RXyy7KQOVs=
 cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9ullr3+Kg0=
+cloud.google.com/go/storage v1.22.1/go.mod h1:S8N1cAStu7BOeFfE8KAQzmyyLkK8p/vmRq6kuBTW58Y=
 dmitri.shuralyov.com/app/changes v0.0.0-20180602232624-0a106ad413e3/go.mod h1:Yl+fi1br7+Rr3LqpNJf1/uxUdtRUV+Tnj0o93V2B9MU=
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 dmitri.shuralyov.com/html/belt v0.0.0-20180602232347-f7d459c86be0/go.mod h1:JLBrvjyP0v+ecvNYvCpyZgu5/xkfAUhi6wJj28eUfSU=
@@ -133,11 +143,14 @@ github.com/cncf/udpa/go v0.0.0-20210930031921-04548b0d99d4/go.mod h1:6pvJx4me5XP
 github.com/cncf/xds/go v0.0.0-20210312221358-fbca930ec8ed/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cncf/xds/go v0.0.0-20210805033703-aa0b78936158/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cncf/xds/go v0.0.0-20210922020428-25de7278fc84/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
+github.com/cncf/xds/go v0.0.0-20211001041855-01bcc9b48dfe/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cncf/xds/go v0.0.0-20211011173535-cb28da3451f1/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/coredns/caddy v1.1.1 h1:2eYKZT7i6yxIfGP3qLJoJ7HAsDJqYB+X68g4NYjSrE0=
 github.com/coredns/caddy v1.1.1/go.mod h1:A6ntJQlAWuQfFlsd9hvigKbo2WS0VUs2l1e2F+BawD4=
 github.com/coredns/coredns v1.8.7 h1:wVMjAnyFnY7Mc18AFO+9qbGD6ODPtdVUIlzoWrHr3hk=
 github.com/coredns/coredns v1.8.7/go.mod h1:bFmbgEfeRz5aizL2VsQ5LRlsvJuXWkgG/MWG9zxqjVM=
+github.com/coreos/go-oidc/v3 v3.4.0 h1:xz7elHb/LDwm/ERpwHd+5nb7wFHL32rsr6bBOgaeu6g=
+github.com/coreos/go-oidc/v3 v3.4.0/go.mod h1:eHUXhZtXPQLgEaDrOVTgwbgmz1xGOkJNye6h3zkD2Pw=
 github.com/coreos/go-semver v0.3.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3EedlOD2RNk=
 github.com/coreos/go-systemd v0.0.0-20181012123002-c6f51f82210d/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
@@ -171,6 +184,7 @@ github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.m
 github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20210512163311-63b5d3c536b0/go.mod h1:hliV/p42l8fGbc6Y9bQ70uLwIvmJyVE5k4iMKlh8wCQ=
 github.com/envoyproxy/go-control-plane v0.9.10-0.20210907150352-cf90f659a021/go.mod h1:AFq3mo9L8Lqqiid3OhADV3RfLJnjiw63cSpi+fDTRC0=
+github.com/envoyproxy/go-control-plane v0.10.2-0.20220325020618-49ff273808a1/go.mod h1:KJwIaB5Mv44NWtYuAOFCVOjcI94vtpEz2JU/D2v6IjE=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/evanphx/json-patch v4.12.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
 github.com/facebookgo/ensure v0.0.0-20160127193407-b4ab57deab51 h1:0JZ+dUmQeA8IIVUMzysrX4/AKuQwWhV2dYQuPZdvdSQ=
@@ -292,8 +306,9 @@ github.com/google/go-cmp v0.5.3/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.7 h1:81/ik6ipDQS2aGcBfIN5dHDB36BwrStyeAQquSYCV4o=
 github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
+github.com/google/go-cmp v0.5.8 h1:e6P7q2lk1O+qJJb4BtCQXlK8vWEO8V1ZeuEdJNOqZyg=
+github.com/google/go-cmp v0.5.8/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/go-github v17.0.0+incompatible/go.mod h1:zLgOLi98H3fifZn+44m+umXrS52loVEgC2AApnigrVQ=
 github.com/google/go-querystring v1.0.0/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
@@ -325,14 +340,19 @@ github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
 github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/googleapis/enterprise-certificate-proxy v0.0.0-20220520183353-fd19c99a87aa/go.mod h1:17drOmN3MwGY7t0e+Ei9b45FFGA3fBs3x36SsCg1hq8=
 github.com/googleapis/gax-go v2.0.0+incompatible/go.mod h1:SFVmujtThgffbyetf+mdk2eWhX2bMyUtNHzFKcPA9HY=
 github.com/googleapis/gax-go/v2 v2.0.3/go.mod h1:LLvjysVCY1JZeum8Z6l8qUty8fiNwE08qbEPm1M08qg=
 github.com/googleapis/gax-go/v2 v2.0.4/go.mod h1:0Wqv26UfaUD9n4G6kQubkQ+KchISgw+vpHVxEJEs9eg=
 github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5mhpdKc/us6bOk=
 github.com/googleapis/gax-go/v2 v2.1.0/go.mod h1:Q3nei7sK6ybPYH7twZdmQpAd1MKb7pfu6SK+H1/DsU0=
 github.com/googleapis/gax-go/v2 v2.1.1/go.mod h1:hddJymUZASv3XPyGkUpKj8pPO47Rmb0eJc8R6ouapiM=
+github.com/googleapis/gax-go/v2 v2.2.0/go.mod h1:as02EH8zWkzwUoLbBaFeQ+arQaj/OthfcblKl4IGNaM=
+github.com/googleapis/gax-go/v2 v2.3.0/go.mod h1:b8LNqSzNabLiUpXKkY7HAR5jr6bIT99EXz9pXxye9YM=
+github.com/googleapis/gax-go/v2 v2.4.0/go.mod h1:XOTVJ59hdnfJLIP/dh8n5CGryZR2LxK9wbMD5+iXC6c=
 github.com/googleapis/gnostic v0.5.1/go.mod h1:6U4PtQXGIEt/Z3h5MAT7FNofLnw9vXk2cUuW7uA/OeU=
 github.com/googleapis/gnostic v0.5.5/go.mod h1:7+EbHbldMins07ALC74bsA81Ovc97DwqyJO1AENw9kA=
+github.com/googleapis/go-type-adapters v1.0.0/go.mod h1:zHW75FOG2aur7gAO2B+MLby+cLsWGBF62rFAi7WjWO4=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
 github.com/gorilla/mux v1.6.2/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
@@ -714,6 +734,12 @@ golang.org/x/net v0.0.0-20210917221730-978cfadd31cf/go.mod h1:9nx3DQGgdP8bBQD5qx
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20211209124913-491a49abca63/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20211216030914-fe4d6282115f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20220127200216-cd36cc0744dd/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
+golang.org/x/net v0.0.0-20220225172249-27dd8689420f/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
+golang.org/x/net v0.0.0-20220325170049-de3da57026de/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
+golang.org/x/net v0.0.0-20220412020605-290c469a71a5/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
+golang.org/x/net v0.0.0-20220425223048-2871e0cb64e4/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
+golang.org/x/net v0.0.0-20220607020251-c690dde0001d/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.0.0-20220909164309-bea034e7d591 h1:D0B/7al0LLrVC8aWF4+oxpv/m8bc7ViFfVS8/gXGdqI=
 golang.org/x/net v0.0.0-20220909164309-bea034e7d591/go.mod h1:YDH+HFinaLZZlnHAfSS6ZXJJ9M9t4Dl22yv3iI2vPwk=
@@ -734,8 +760,13 @@ golang.org/x/oauth2 v0.0.0-20210514164344-f6687ab2804c/go.mod h1:KelEdhl1UZF7XfJ
 golang.org/x/oauth2 v0.0.0-20210628180205-a41e5a781914/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
 golang.org/x/oauth2 v0.0.0-20210805134026-6f1e6394065a/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
 golang.org/x/oauth2 v0.0.0-20210819190943-2bc19b11175f/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
-golang.org/x/oauth2 v0.0.0-20211104180415-d3ed0bb246c8 h1:RerP+noqYHUQ8CMRcPlC2nvTa4dcBIjegkuWdcUDuqg=
 golang.org/x/oauth2 v0.0.0-20211104180415-d3ed0bb246c8/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
+golang.org/x/oauth2 v0.0.0-20220223155221-ee480838109b/go.mod h1:DAh4E804XQdzx2j+YRIaUnCqCV2RuMz24cGBJ5QYIrc=
+golang.org/x/oauth2 v0.0.0-20220309155454-6242fa91716a/go.mod h1:DAh4E804XQdzx2j+YRIaUnCqCV2RuMz24cGBJ5QYIrc=
+golang.org/x/oauth2 v0.0.0-20220411215720-9780585627b5/go.mod h1:DAh4E804XQdzx2j+YRIaUnCqCV2RuMz24cGBJ5QYIrc=
+golang.org/x/oauth2 v0.0.0-20220608161450-d0670ef3b1eb/go.mod h1:jaDAt6Dkxork7LmZnYtzbRWj0W47D86a3TGe0YHBvmE=
+golang.org/x/oauth2 v0.0.0-20220822191816-0ebed06d0094 h1:2o1E+E8TpNLklK9nHiPiK1uzIYrIHt+cQx3ynCwq9V8=
+golang.org/x/oauth2 v0.0.0-20220822191816-0ebed06d0094/go.mod h1:h4gKUeWbJ4rQPri7E0u6Gs4e9Ri2zaLxzw5DI5XGrYg=
 golang.org/x/perf v0.0.0-20180704124530-6e6d33e29852/go.mod h1:JLpeXjPJfIyPr5TlbXLkXWLhP8nz10XfvxElABhCtcw=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -747,8 +778,9 @@ golang.org/x/sync v0.0.0-20200317015054-43a5402ce75a/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20210220032951-036812b2e83c h1:5KslGYwFpkhGh+Q16bwMP3cOontH8FOep7tGV86Y7SQ=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f h1:Ax0t5p6N38Ga0dThY21weqDEyz2oklo4IvDkpigvkD8=
+golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -819,9 +851,19 @@ golang.org/x/sys v0.0.0-20210823070655-63515b42dcdf/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20210831042530-f4d43177bf5e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210908233432-aa78b53d3365/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211124211545-fe61309f8881/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211210111614-af8b64212486/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220114195835-da31bd327af9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220128215802-99c3d69c2c27/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220227234510-4e6760a101f9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220328115105-d36c6a25d886/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220412211240-33da011f77ad/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220502124256-b6088ccd6cba/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220503163025-988cb79eb6c6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220610221304-9f5ed59c137d/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220808155132-1c4a2a72c664 h1:v1W7bwXHsnLLloWYTVEdvGvA7BHMeBYsPcF0GLDxIRs=
 golang.org/x/sys v0.0.0-20220808155132-1c4a2a72c664/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
@@ -907,8 +949,11 @@ golang.org/x/tools v0.1.6-0.20210726203631-07bc1bf47fb2/go.mod h1:o0xws9oXOQQZyj
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20220411194840-2f41105eb62f/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20220517211312-f3a8303e98df/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
+golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f h1:uF6paiQQebLeSXkrTqHqz0MXhXXS1KgF41eUdBNvxK0=
+golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
 google.golang.org/api v0.0.0-20180910000450-7ca32eb868bf/go.mod h1:4mhQ8q/RsB7i+udVvVy5NUi08OU8ZlA0gRVgrF7VFY0=
 google.golang.org/api v0.0.0-20181030000543-1d582fd0359e/go.mod h1:4mhQ8q/RsB7i+udVvVy5NUi08OU8ZlA0gRVgrF7VFY0=
 google.golang.org/api v0.1.0/go.mod h1:UGEZY7KEX120AnNLIHFMKIo4obdJhkp2tPbaPlQx13Y=
@@ -942,7 +987,16 @@ google.golang.org/api v0.55.0/go.mod h1:38yMfeP1kfjsl8isn0tliTjIb1rJXcQi4UXlbqiv
 google.golang.org/api v0.56.0/go.mod h1:38yMfeP1kfjsl8isn0tliTjIb1rJXcQi4UXlbqivdVE=
 google.golang.org/api v0.57.0/go.mod h1:dVPlbZyBo2/OjBpmvNdpn2GRm6rPy75jyU7bmhdrMgI=
 google.golang.org/api v0.61.0/go.mod h1:xQRti5UdCmoCEqFxcz93fTl338AVqDgyaDRuOZ3hg9I=
+google.golang.org/api v0.63.0/go.mod h1:gs4ij2ffTRXwuzzgJl/56BdwJaA194ijkfn++9tDuPo=
 google.golang.org/api v0.64.0/go.mod h1:931CdxA8Rm4t6zqTFGSsgwbAEZ2+GMYurbndwSimebM=
+google.golang.org/api v0.67.0/go.mod h1:ShHKP8E60yPsKNw/w8w+VYaj9H6buA5UqDp8dhbQZ6g=
+google.golang.org/api v0.70.0/go.mod h1:Bs4ZM2HGifEvXwd50TtW70ovgJffJYw2oRCOFU/SkfA=
+google.golang.org/api v0.71.0/go.mod h1:4PyU6e6JogV1f9eA4voyrTY2batOLdgZ5qZ5HOCc4j8=
+google.golang.org/api v0.74.0/go.mod h1:ZpfMZOVRMywNyvJFeqL9HRWBgAuRfSjJFpe9QtRRyDs=
+google.golang.org/api v0.75.0/go.mod h1:pU9QmyHLnzlpar1Mjt4IbapUCy8J+6HD6GeELN69ljA=
+google.golang.org/api v0.78.0/go.mod h1:1Sg78yoMLOhlQTeF+ARBoytAcH1NNyyl390YMy6rKmw=
+google.golang.org/api v0.80.0/go.mod h1:xY3nI94gbvBrE0J6NHXhxOmW97HG7Khjkku6AFB3Hyg=
+google.golang.org/api v0.84.0/go.mod h1:NTsGnUFJMYROtiquksZHBWtHfeMC7iYthki7Eq3pa8o=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.2.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/appengine v1.3.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
@@ -997,6 +1051,7 @@ google.golang.org/genproto v0.0.0-20210222152913-aa3ee6e6a81c/go.mod h1:FWY/as6D
 google.golang.org/genproto v0.0.0-20210303154014-9728d6b83eeb/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/genproto v0.0.0-20210310155132-4ce2db91004e/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
 google.golang.org/genproto v0.0.0-20210319143718-93e7006c17a6/go.mod h1:FWY/as6DDZQgahTzZj3fqbO1CbirC29ZNUFHwi0/+no=
+google.golang.org/genproto v0.0.0-20210329143202-679c6ae281ee/go.mod h1:9lPAdzaEmUacj36I+k7YKbEc5CXzPIeORRgDAUOu28A=
 google.golang.org/genproto v0.0.0-20210402141018-6c239bbf2bb1/go.mod h1:9lPAdzaEmUacj36I+k7YKbEc5CXzPIeORRgDAUOu28A=
 google.golang.org/genproto v0.0.0-20210513213006-bf773b8c8384/go.mod h1:P3QM42oQyzQSnHPnZ/vqoCdDmzH28fzWByN9asMeM8A=
 google.golang.org/genproto v0.0.0-20210602131652-f16073e35f0c/go.mod h1:UODoCrxHCcBojKKwX1terBiRUaqAsFqJiF615XL43r0=
@@ -1016,8 +1071,27 @@ google.golang.org/genproto v0.0.0-20210909211513-a8c4777a87af/go.mod h1:eFjDcFEc
 google.golang.org/genproto v0.0.0-20210924002016-3dee208752a0/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
 google.golang.org/genproto v0.0.0-20211118181313-81c1377c94b1/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
 google.golang.org/genproto v0.0.0-20211206160659-862468c7d6e0/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
-google.golang.org/genproto v0.0.0-20211223182754-3ac035c7e7cb h1:ZrsicilzPCS/Xr8qtBZZLpy4P9TYXAfl49ctG1/5tgw=
+google.golang.org/genproto v0.0.0-20211208223120-3a66f561d7aa/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
+google.golang.org/genproto v0.0.0-20211221195035-429b39de9b1c/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
 google.golang.org/genproto v0.0.0-20211223182754-3ac035c7e7cb/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
+google.golang.org/genproto v0.0.0-20220126215142-9970aeb2e350/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
+google.golang.org/genproto v0.0.0-20220207164111-0872dc986b00/go.mod h1:5CzLGKJ67TSI2B9POpiiyGha0AjJvZIUgRMt1dSmuhc=
+google.golang.org/genproto v0.0.0-20220218161850-94dd64e39d7c/go.mod h1:kGP+zUP2Ddo0ayMi4YuN7C3WZyJvGLZRh8Z5wnAqvEI=
+google.golang.org/genproto v0.0.0-20220222213610-43724f9ea8cf/go.mod h1:kGP+zUP2Ddo0ayMi4YuN7C3WZyJvGLZRh8Z5wnAqvEI=
+google.golang.org/genproto v0.0.0-20220304144024-325a89244dc8/go.mod h1:kGP+zUP2Ddo0ayMi4YuN7C3WZyJvGLZRh8Z5wnAqvEI=
+google.golang.org/genproto v0.0.0-20220310185008-1973136f34c6/go.mod h1:kGP+zUP2Ddo0ayMi4YuN7C3WZyJvGLZRh8Z5wnAqvEI=
+google.golang.org/genproto v0.0.0-20220324131243-acbaeb5b85eb/go.mod h1:hAL49I2IFola2sVEjAn7MEwsja0xp51I0tlGAf9hz4E=
+google.golang.org/genproto v0.0.0-20220407144326-9054f6ed7bac/go.mod h1:8w6bsBMX6yCPbAVTeqQHvzxW0EIFigd5lZyahWgyfDo=
+google.golang.org/genproto v0.0.0-20220413183235-5e96e2839df9/go.mod h1:8w6bsBMX6yCPbAVTeqQHvzxW0EIFigd5lZyahWgyfDo=
+google.golang.org/genproto v0.0.0-20220414192740-2d67ff6cf2b4/go.mod h1:8w6bsBMX6yCPbAVTeqQHvzxW0EIFigd5lZyahWgyfDo=
+google.golang.org/genproto v0.0.0-20220421151946-72621c1f0bd3/go.mod h1:8w6bsBMX6yCPbAVTeqQHvzxW0EIFigd5lZyahWgyfDo=
+google.golang.org/genproto v0.0.0-20220429170224-98d788798c3e/go.mod h1:8w6bsBMX6yCPbAVTeqQHvzxW0EIFigd5lZyahWgyfDo=
+google.golang.org/genproto v0.0.0-20220505152158-f39f71e6c8f3/go.mod h1:RAyBrSAP7Fh3Nc84ghnVLDPuV51xc9agzmm4Ph6i0Q4=
+google.golang.org/genproto v0.0.0-20220518221133-4f43b3371335/go.mod h1:RAyBrSAP7Fh3Nc84ghnVLDPuV51xc9agzmm4Ph6i0Q4=
+google.golang.org/genproto v0.0.0-20220523171625-347a074981d8/go.mod h1:RAyBrSAP7Fh3Nc84ghnVLDPuV51xc9agzmm4Ph6i0Q4=
+google.golang.org/genproto v0.0.0-20220608133413-ed9918b62aac/go.mod h1:KEWEmljWE5zPzLBa/oHl6DaEt9LmfH6WtH1OHIvleBA=
+google.golang.org/genproto v0.0.0-20220616135557-88e70c0c3a90 h1:4SPz2GL2CXJt28MTF8V6Ap/9ZiVbQlJeGSd9qtA7DLs=
+google.golang.org/genproto v0.0.0-20220616135557-88e70c0c3a90/go.mod h1:KEWEmljWE5zPzLBa/oHl6DaEt9LmfH6WtH1OHIvleBA=
 google.golang.org/grpc v1.14.0/go.mod h1:yo6s7OP7yaDglbqo1J04qKzAhqBH6lvTonzMVmEdcZw=
 google.golang.org/grpc v1.16.0/go.mod h1:0JHn/cJsOMiMfNA9+DeHDlAU7KAAB5GDlYFpa9MZMio=
 google.golang.org/grpc v1.17.0/go.mod h1:6QZJwpn2B+Zp71q/5VxRsJ6NXXVCE5NRUHRo+f3cWCs=
@@ -1052,8 +1126,12 @@ google.golang.org/grpc v1.40.1/go.mod h1:ogyxbiOoUXAkP+4+xa6PZSE9DZgIHtSpzjDTB9K
 google.golang.org/grpc v1.41.0/go.mod h1:U3l9uK9J0sini8mHphKoXyaqDA/8VyGnDee1zzIUK6k=
 google.golang.org/grpc v1.42.0/go.mod h1:k+4IHHFw41K8+bbowsex27ge2rCb65oeWqe4jJ590SU=
 google.golang.org/grpc v1.43.0/go.mod h1:k+4IHHFw41K8+bbowsex27ge2rCb65oeWqe4jJ590SU=
-google.golang.org/grpc v1.45.0 h1:NEpgUqV3Z+ZjkqMsxMg11IaDrXY4RY6CQukSGK0uI1M=
+google.golang.org/grpc v1.44.0/go.mod h1:k+4IHHFw41K8+bbowsex27ge2rCb65oeWqe4jJ590SU=
 google.golang.org/grpc v1.45.0/go.mod h1:lN7owxKUQEqMfSyQikvvk5tf/6zMPsrK+ONuO11+0rQ=
+google.golang.org/grpc v1.46.0/go.mod h1:vN9eftEi1UMyUsIF80+uQXhHjbXYbm0uXoFCACuMGWk=
+google.golang.org/grpc v1.46.2/go.mod h1:vN9eftEi1UMyUsIF80+uQXhHjbXYbm0uXoFCACuMGWk=
+google.golang.org/grpc v1.47.0 h1:9n77onPX5F3qfFCqjy9dhn8PbNQsIKeVU04J9G7umt8=
+google.golang.org/grpc v1.47.0/go.mod h1:vN9eftEi1UMyUsIF80+uQXhHjbXYbm0uXoFCACuMGWk=
 google.golang.org/grpc/cmd/protoc-gen-go-grpc v1.1.0/go.mod h1:6Kw0yEErY5E/yWrBtf03jp27GLLJujG4z/JK95pnjjw=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
@@ -113,11 +113,12 @@ func (snf echoFunnelID) String() string {
 	return strconv.FormatUint(uint64(snf), 10)
 }

-func newICMPProxy(listenIP netip.Addr, logger *zerolog.Logger, idleTimeout time.Duration) (*icmpProxy, error) {
-	conn, err := newICMPConn(listenIP)
+func newICMPProxy(listenIP netip.Addr, zone string, logger *zerolog.Logger, idleTimeout time.Duration) (*icmpProxy, error) {
+	conn, err := newICMPConn(listenIP, zone)
 	if err != nil {
 		return nil, err
 	}
+	logger.Info().Msgf("Created ICMP proxy listening on %s", conn.LocalAddr())
 	return &icmpProxy{
 		srcFunnelTracker: packet.NewFunnelTracker(),
 		echoIDTracker:    newEchoIDTracker(),
@@ -26,6 +26,6 @@ func (ip *icmpProxy) Serve(ctx context.Context) error {
 	return errICMPProxyNotImplemented
 }

-func newICMPProxy(listenIP netip.Addr, logger *zerolog.Logger, idleTimeout time.Duration) (*icmpProxy, error) {
+func newICMPProxy(listenIP netip.Addr, zone string, logger *zerolog.Logger, idleTimeout time.Duration) (*icmpProxy, error) {
 	return nil, errICMPProxyNotImplemented
 }
@@ -12,6 +12,9 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"os"
+	"regexp"
+	"strconv"
 	"time"

 	"github.com/pkg/errors"
@@ -21,31 +24,47 @@ import (
 	"github.com/cloudflare/cloudflared/packet"
 )

+const (
+	// https://lwn.net/Articles/550551/ IPv4 and IPv6 share the same path
+	pingGroupPath = "/proc/sys/net/ipv4/ping_group_range"
+)
+
+var (
+	findGroupIDRegex = regexp.MustCompile(`\d+`)
+)
+
 type icmpProxy struct {
 	srcFunnelTracker *packet.FunnelTracker
 	listenIP         netip.Addr
+	ipv6Zone         string
 	logger           *zerolog.Logger
 	idleTimeout      time.Duration
 }

-func newICMPProxy(listenIP netip.Addr, logger *zerolog.Logger, idleTimeout time.Duration) (*icmpProxy, error) {
-	if err := testPermission(listenIP); err != nil {
+func newICMPProxy(listenIP netip.Addr, zone string, logger *zerolog.Logger, idleTimeout time.Duration) (*icmpProxy, error) {
+	if err := testPermission(listenIP, zone, logger); err != nil {
 		return nil, err
 	}
 	return &icmpProxy{
 		srcFunnelTracker: packet.NewFunnelTracker(),
 		listenIP:         listenIP,
+		ipv6Zone:         zone,
 		logger:           logger,
 		idleTimeout:      idleTimeout,
 	}, nil
 }

-func testPermission(listenIP netip.Addr) error {
+func testPermission(listenIP netip.Addr, zone string, logger *zerolog.Logger) error {
 	// Opens a non-privileged ICMP socket. On Linux the group ID of the process needs to be in ping_group_range
-	conn, err := newICMPConn(listenIP)
+	// Only check ping_group_range once for IPv4
+	if listenIP.Is4() {
+		if err := checkInPingGroup(); err != nil {
+			logger.Warn().Err(err).Msgf("The user running cloudflared process has a GID (group ID) that is not within ping_group_range. You might need to add that user to a group within that range, or instead update the range to encompass a group the user is already in by modifying %s. Otherwise cloudflared will not be able to ping this network", pingGroupPath)
+			return err
+		}
+	}
+	conn, err := newICMPConn(listenIP, zone)
 	if err != nil {
-		// TODO: TUN-6715 check if cloudflared is in ping_group_range if the check failed. If not log instruction to
-		// change the group ID
 		return err
 	}
 	// This conn is only to test if cloudflared has permission to open this type of socket
@@ -53,6 +72,31 @@ func testPermission(listenIP netip.Addr) error {
 	return nil
 }

+func checkInPingGroup() error {
+	file, err := os.ReadFile(pingGroupPath)
+	if err != nil {
+		return err
+	}
+	groupID := os.Getgid()
+	// Example content: 999	   59999
+	found := findGroupIDRegex.FindAll(file, 2)
+	if len(found) == 2 {
+		groupMin, err := strconv.ParseInt(string(found[0]), 10, 32)
+		if err != nil {
+			return errors.Wrapf(err, "failed to determine minimum ping group ID")
+		}
+		groupMax, err := strconv.ParseInt(string(found[1]), 10, 32)
+		if err != nil {
+			return errors.Wrapf(err, "failed to determine minimum ping group ID")
+		}
+		if groupID < int(groupMin) || groupID > int(groupMax) {
+			return fmt.Errorf("Group ID %d is not between ping group %d to %d", groupID, groupMin, groupMax)
+		}
+		return nil
+	}
+	return fmt.Errorf("did not find group range in %s", pingGroupPath)
+}
+
 func (ip *icmpProxy) Request(pk *packet.ICMP, responder packet.FunnelUniPipe) error {
 	if pk == nil {
 		return errPacketNil
@@ -63,10 +107,11 @@ func (ip *icmpProxy) Request(pk *packet.ICMP, responder packet.FunnelUniPipe) er
 	}
 	newConnChan := make(chan *icmp.PacketConn, 1)
 	newFunnelFunc := func() (packet.Funnel, error) {
-		conn, err := newICMPConn(ip.listenIP)
+		conn, err := newICMPConn(ip.listenIP, ip.ipv6Zone)
 		if err != nil {
 			return nil, errors.Wrap(err, "failed to open ICMP socket")
 		}
+		ip.logger.Debug().Msgf("Opened ICMP socket listen on %s", conn.LocalAddr())
 		newConnChan <- conn
 		localUDPAddr, ok := conn.LocalAddr().(*net.UDPAddr)
 		if !ok {
@@ -16,12 +16,15 @@ import (
 )

 // Opens a non-privileged ICMP socket on Linux and Darwin
-func newICMPConn(listenIP netip.Addr) (*icmp.PacketConn, error) {
-	network := "udp6"
+func newICMPConn(listenIP netip.Addr, zone string) (*icmp.PacketConn, error) {
 	if listenIP.Is4() {
-		network = "udp4"
+		return icmp.ListenPacket("udp4", listenIP.String())
 	}
-	return icmp.ListenPacket(network, listenIP.String())
+	listenAddr := listenIP.String()
+	if zone != "" {
+		listenAddr = listenAddr + "%" + zone
+	}
+	return icmp.ListenPacket("udp6", listenAddr)
 }

 func netipAddr(addr net.Addr) (netip.Addr, bool) {
@@ -24,7 +24,7 @@ func TestFunnelIdleTimeout(t *testing.T) {
 		startSeq    = 8129
 	)
 	logger := zerolog.New(os.Stderr)
-	proxy, err := newICMPProxy(localhostIP, &logger, idleTimeout)
+	proxy, err := newICMPProxy(localhostIP, "", &logger, idleTimeout)
 	require.NoError(t, err)

 	ctx, cancel := context.WithCancel(context.Background())
@@ -224,7 +224,7 @@ type icmpProxy struct {
 	encoderPool sync.Pool
 }

-func newICMPProxy(listenIP netip.Addr, logger *zerolog.Logger, idleTimeout time.Duration) (*icmpProxy, error) {
+func newICMPProxy(listenIP netip.Addr, zone string, logger *zerolog.Logger, idleTimeout time.Duration) (*icmpProxy, error) {
 	var (
 		srcSocketAddr *sockAddrIn6
 		handle        uintptr
@@ -262,6 +262,9 @@ func (ip *icmpProxy) Serve(ctx context.Context) error {
 	return ctx.Err()
 }

+// Request sends an ICMP echo request and wait for a reply or timeout.
+// The async version of Win32 APIs take a callback whose memory is not garbage collected, so we use the synchronous version.
+// It's possible that a slow request will block other requests, so we set the timeout to only 1s.
 func (ip *icmpProxy) Request(pk *packet.ICMP, responder packet.FunnelUniPipe) error {
 	if pk == nil {
 		return errPacketNil
@@ -132,7 +132,7 @@ func TestSendEchoErrors(t *testing.T) {
 }

 func testSendEchoErrors(t *testing.T, listenIP netip.Addr) {
-	proxy, err := newICMPProxy(listenIP, &noopLogger, time.Second)
+	proxy, err := newICMPProxy(listenIP, "", &noopLogger, time.Second)
 	require.NoError(t, err)

 	echo := icmp.Echo{
@@ -11,8 +11,10 @@ import (
 	"github.com/pkg/errors"
 	"github.com/rs/zerolog"
 	"github.com/urfave/cli/v2"
+	"golang.org/x/net/idna"

 	"github.com/cloudflare/cloudflared/config"
+	"github.com/cloudflare/cloudflared/ingress/middleware"
 	"github.com/cloudflare/cloudflared/ipaccess"
 )

@@ -168,6 +170,28 @@ func (ing Ingress) CatchAll() *Rule {
 	return &ing.Rules[len(ing.Rules)-1]
 }

+func validateAccessConfiguration(cfg *config.AccessConfig) error {
+	if !cfg.Required {
+		return nil
+	}
+
+	// It is possible to set `required:true` and not have these two configured yet.
+	// But if one of them is configured, we'd validate for correctness.
+	if len(cfg.AudTag) == 0 && cfg.TeamName == "" {
+		return nil
+	}
+
+	if len(cfg.AudTag) == 0 {
+		return errors.New("access audtag cannot be empty")
+	}
+
+	if cfg.TeamName == "" {
+		return errors.New("access.TeamName cannot be blank")
+	}
+
+	return nil
+}
+
 func validateIngress(ingress []config.UnvalidatedIngressRule, defaults OriginRequestConfig) (Ingress, error) {
 	rules := make([]Rule, len(ingress))
 	for i, r := range ingress {
@@ -237,10 +261,31 @@ func validateIngress(ingress []config.UnvalidatedIngressRule, defaults OriginReq
 			}
 		}

+		var handlers []middleware.Handler
+		if access := r.OriginRequest.Access; access != nil {
+			if err := validateAccessConfiguration(access); err != nil {
+				return Ingress{}, err
+			}
+			if access.Required {
+				verifier := middleware.NewJWTValidator(access.TeamName, "", access.AudTag)
+				handlers = append(handlers, verifier)
+			}
+		}
+
 		if err := validateHostname(r, i, len(ingress)); err != nil {
 			return Ingress{}, err
 		}

+		isCatchAllRule := (r.Hostname == "" || r.Hostname == "*") && r.Path == ""
+		punycodeHostname := ""
+		if !isCatchAllRule {
+			punycode, err := idna.Lookup.ToASCII(r.Hostname)
+			// Don't provide the punycode hostname if it is the same as the original hostname
+			if err == nil && punycode != r.Hostname {
+				punycodeHostname = punycode
+			}
+		}
+
 		var pathRegexp *Regexp
 		if r.Path != "" {
 			var err error
@@ -252,10 +297,12 @@ func validateIngress(ingress []config.UnvalidatedIngressRule, defaults OriginReq
 		}

 		rules[i] = Rule{
-			Hostname: r.Hostname,
-			Service:  service,
-			Path:     pathRegexp,
-			Config:   cfg,
+			Hostname:         r.Hostname,
+			punycodeHostname: punycodeHostname,
+			Service:          service,
+			Path:             pathRegexp,
+			Handlers:         handlers,
+			Config:           cfg,
 		}
 	}
 	return Ingress{Rules: rules, Defaults: defaults}, nil
@@ -130,6 +130,36 @@ ingress:
 				},
 			},
 		},
+		{
+			name: "Unicode domain",
+			args: args{rawYAML: `
+ingress:
+ - hostname: môô.cloudflare.com
+   service: https://localhost:8000
+ - service: https://localhost:8001
+`},
+			want: []Rule{
+				{
+					Hostname:         "môô.cloudflare.com",
+					punycodeHostname: "xn--m-xgaa.cloudflare.com",
+					Service:          &httpService{url: localhost8000},
+					Config:           defaultConfig,
+				},
+				{
+					Service: &httpService{url: localhost8001},
+					Config:  defaultConfig,
+				},
+			},
+		},
+		{
+			name: "Invalid unicode domain",
+			args: args{rawYAML: fmt.Sprintf(`
+ingress:
+ - hostname: %s
+   service: https://localhost:8000
+`, string(rune(0xd8f3))+".cloudflare.com")},
+			wantErr: true,
+		},
 		{
 			name: "Invalid service",
 			args: args{rawYAML: `
@@ -0,0 +1,79 @@
+package middleware
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+
+	"github.com/coreos/go-oidc/v3/oidc"
+)
+
+const (
+	headerKeyAccessJWTAssertion = "Cf-Access-Jwt-Assertion"
+)
+
+var (
+	cloudflareAccessCertsURL = "https://%s.cloudflareaccess.com"
+)
+
+// JWTValidator is an implementation of Verifier that validates access based JWT tokens.
+type JWTValidator struct {
+	*oidc.IDTokenVerifier
+	audTags []string
+}
+
+func NewJWTValidator(teamName string, certsURL string, audTags []string) *JWTValidator {
+	if certsURL == "" {
+		certsURL = fmt.Sprintf(cloudflareAccessCertsURL, teamName)
+	}
+	certsEndpoint := fmt.Sprintf("%s/cdn-cgi/access/certs", certsURL)
+
+	config := &oidc.Config{
+		SkipClientIDCheck: true,
+	}
+
+	ctx := context.Background()
+	keySet := oidc.NewRemoteKeySet(ctx, certsEndpoint)
+	verifier := oidc.NewVerifier(certsURL, keySet, config)
+	return &JWTValidator{
+		IDTokenVerifier: verifier,
+		audTags:         audTags,
+	}
+}
+
+func (v *JWTValidator) Name() string {
+	return "AccessJWTValidator"
+}
+
+func (v *JWTValidator) Handle(ctx context.Context, r *http.Request) (*HandleResult, error) {
+	accessJWT := r.Header.Get(headerKeyAccessJWTAssertion)
+	if accessJWT == "" {
+		// log the exact error message here. the message is specific to the handler implementation logic, we don't gain anything
+		// in passing it upstream. and each handler impl know what logging level to use for each.
+		return &HandleResult{
+			ShouldFilterRequest: true,
+			StatusCode:          http.StatusForbidden,
+			Reason:              "no access token in request",
+		}, nil
+	}
+
+	token, err := v.IDTokenVerifier.Verify(ctx, accessJWT)
+	if err != nil {
+		return nil, err
+	}
+
+	// We want at least one audTag to match
+	for _, jwtAudTag := range token.Audience {
+		for _, acceptedAudTag := range v.audTags {
+			if acceptedAudTag == jwtAudTag {
+				return &HandleResult{ShouldFilterRequest: false}, nil
+			}
+		}
+	}
+
+	return &HandleResult{
+		ShouldFilterRequest: true,
+		StatusCode:          http.StatusForbidden,
+		Reason:              fmt.Sprintf("Invalid token in jwt: %v", token.Audience),
+	}, nil
+}
@@ -0,0 +1,19 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+)
+
+type HandleResult struct {
+	// Tells that the request didn't passed the handler and should be filtered
+	ShouldFilterRequest bool
+	// The status code to return in case ShouldFilterRequest is true.
+	StatusCode int
+	Reason     string
+}
+
+type Handler interface {
+	Name() string
+	Handle(ctx context.Context, r *http.Request) (result *HandleResult, err error)
+}
@@ -33,10 +33,9 @@ type icmpRouter struct {

 // NewICMPRouter doesn't return an error if either ipv4 proxy or ipv6 proxy can be created. The machine might only
 // support one of them
-func NewICMPRouter(logger *zerolog.Logger) (*icmpRouter, error) {
-	// TODO: TUN-6741: don't bind to all interface
-	ipv4Proxy, ipv4Err := newICMPProxy(netip.IPv4Unspecified(), logger, funnelIdleTimeout)
-	ipv6Proxy, ipv6Err := newICMPProxy(netip.IPv6Unspecified(), logger, funnelIdleTimeout)
+func NewICMPRouter(ipv4Addr, ipv6Addr netip.Addr, ipv6Zone string, logger *zerolog.Logger) (*icmpRouter, error) {
+	ipv4Proxy, ipv4Err := newICMPProxy(ipv4Addr, "", logger, funnelIdleTimeout)
+	ipv6Proxy, ipv6Err := newICMPProxy(ipv6Addr, ipv6Zone, logger, funnelIdleTimeout)
 	if ipv4Err != nil && ipv6Err != nil {
 		return nil, fmt.Errorf("cannot create ICMPv4 proxy: %v nor ICMPv6 proxy: %v", ipv4Err, ipv6Err)
 	}
@@ -42,7 +42,7 @@ func testICMPRouterEcho(t *testing.T, sendIPv4 bool) {
 		endSeq = 20
 	)

-	router, err := NewICMPRouter(&noopLogger)
+	router, err := NewICMPRouter(localhostIP, localhostIPv6, "", &noopLogger)
 	require.NoError(t, err)

 	proxyDone := make(chan struct{})
@@ -106,7 +106,7 @@ func TestConcurrentRequestsToSameDst(t *testing.T) {
 		endSeq          = 5
 	)

-	router, err := NewICMPRouter(&noopLogger)
+	router, err := NewICMPRouter(localhostIP, localhostIPv6, "", &noopLogger)
 	require.NoError(t, err)

 	proxyDone := make(chan struct{})
@@ -238,7 +238,7 @@ func TestICMPRouterRejectNotEcho(t *testing.T) {
 }

 func testICMPRouterRejectNotEcho(t *testing.T, srcDstIP netip.Addr, msgs []icmp.Message) {
-	router, err := NewICMPRouter(&noopLogger)
+	router, err := NewICMPRouter(localhostIP, localhostIPv6, "", &noopLogger)
 	require.NoError(t, err)

 	responder := echoFlowResponder{
@@ -299,12 +299,7 @@ func (efr *echoFlowResponder) validate(t *testing.T, echoReq *packet.ICMP) {
 		require.Equal(t, ipv6.ICMPTypeEchoReply, decoded.Type)
 	}
 	require.Equal(t, 0, decoded.Code)
-	if echoReq.Type == ipv4.ICMPTypeEcho {
-		require.NotZero(t, decoded.Checksum)
-	} else {
-		// For ICMPv6, the kernel will compute the checksum during transmission unless pseudo header is not nil
-		require.Zero(t, decoded.Checksum)
-	}
+	require.NotZero(t, decoded.Checksum)

 	require.Equal(t, echoReq.Body, decoded.Body)
 }
@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"regexp"
 	"strings"
+
+	"github.com/cloudflare/cloudflared/ingress/middleware"
 )

 // Rule routes traffic from a hostname/path on the public internet to the
@@ -12,6 +14,9 @@ type Rule struct {
 	// Requests for this hostname will be proxied to this rule's service.
 	Hostname string `json:"hostname"`

+	// punycodeHostname is an additional optional hostname converted to punycode.
+	punycodeHostname string
+
 	// Path is an optional regex that can specify path-driven ingress rules.
 	Path *Regexp `json:"path"`

@@ -20,6 +25,9 @@ type Rule struct {
 	// address.
 	Service OriginService `json:"service"`

+	// Handlers is a list of functions that acts as a middleware during ProxyHTTP
+	Handlers []middleware.Handler
+
 	// Configure the request cloudflared sends to this specific origin.
 	Config OriginRequestConfig `json:"originRequest"`
 }
@@ -45,9 +53,18 @@ func (r Rule) MultiLineString() string {

 // Matches checks if the rule matches a given hostname/path combination.
 func (r *Rule) Matches(hostname, path string) bool {
-	hostMatch := r.Hostname == "" || r.Hostname == "*" || matchHost(r.Hostname, hostname)
+	hostMatch := false
+	if r.Hostname == "" || r.Hostname == "*" {
+		hostMatch = true
+	} else {
+		hostMatch = matchHost(r.Hostname, hostname)
+	}
+	punycodeHostMatch := false
+	if r.punycodeHostname != "" {
+		punycodeHostMatch = matchHost(r.punycodeHostname, hostname)
+	}
 	pathMatch := r.Path == nil || r.Path.Regexp == nil || r.Path.Regexp.MatchString(path)
-	return hostMatch && pathMatch
+	return (hostMatch || punycodeHostMatch) && pathMatch
 }

 // Regexp adds unmarshalling from json for regexp.Regexp
@@ -14,23 +14,18 @@ import (
 )

 func Test_rule_matches(t *testing.T) {
-	type fields struct {
-		Hostname string
-		Path     *Regexp
-		Service  OriginService
-	}
 	type args struct {
 		requestURL *url.URL
 	}
 	tests := []struct {
-		name   string
-		fields fields
-		args   args
-		want   bool
+		name string
+		rule Rule
+		args args
+		want bool
 	}{
 		{
 			name: "Just hostname, pass",
-			fields: fields{
+			rule: Rule{
 				Hostname: "example.com",
 			},
 			args: args{
@@ -38,9 +33,31 @@ func Test_rule_matches(t *testing.T) {
 			},
 			want: true,
 		},
+		{
+			name: "Unicode hostname with unicode request, pass",
+			rule: Rule{
+				Hostname:         "môô.cloudflare.com",
+				punycodeHostname: "xn--m-xgaa.cloudflare.com",
+			},
+			args: args{
+				requestURL: MustParseURL(t, "https://môô.cloudflare.com"),
+			},
+			want: true,
+		},
+		{
+			name: "Unicode hostname with punycode request, pass",
+			rule: Rule{
+				Hostname:         "môô.cloudflare.com",
+				punycodeHostname: "xn--m-xgaa.cloudflare.com",
+			},
+			args: args{
+				requestURL: MustParseURL(t, "https://xn--m-xgaa.cloudflare.com"),
+			},
+			want: true,
+		},
 		{
 			name: "Entire hostname is wildcard, should match everything",
-			fields: fields{
+			rule: Rule{
 				Hostname: "*",
 			},
 			args: args{
@@ -50,7 +67,7 @@ func Test_rule_matches(t *testing.T) {
 		},
 		{
 			name: "Just hostname, fail",
-			fields: fields{
+			rule: Rule{
 				Hostname: "example.com",
 			},
 			args: args{
@@ -60,7 +77,7 @@ func Test_rule_matches(t *testing.T) {
 		},
 		{
 			name: "Just wildcard hostname, pass",
-			fields: fields{
+			rule: Rule{
 				Hostname: "*.example.com",
 			},
 			args: args{
@@ -70,7 +87,7 @@ func Test_rule_matches(t *testing.T) {
 		},
 		{
 			name: "Just wildcard hostname, fail",
-			fields: fields{
+			rule: Rule{
 				Hostname: "*.example.com",
 			},
 			args: args{
@@ -80,7 +97,7 @@ func Test_rule_matches(t *testing.T) {
 		},
 		{
 			name: "Just wildcard outside of subdomain in hostname, fail",
-			fields: fields{
+			rule: Rule{
 				Hostname: "*example.com",
 			},
 			args: args{
@@ -90,7 +107,7 @@ func Test_rule_matches(t *testing.T) {
 		},
 		{
 			name: "Wildcard over multiple subdomains",
-			fields: fields{
+			rule: Rule{
 				Hostname: "*.example.com",
 			},
 			args: args{
@@ -100,7 +117,7 @@ func Test_rule_matches(t *testing.T) {
 		},
 		{
 			name: "Hostname and path",
-			fields: fields{
+			rule: Rule{
 				Hostname: "*.example.com",
 				Path:     &Regexp{Regexp: regexp.MustCompile("/static/.*\\.html")},
 			},
@@ -111,7 +128,7 @@ func Test_rule_matches(t *testing.T) {
 		},
 		{
 			name: "Hostname and empty Regex",
-			fields: fields{
+			rule: Rule{
 				Hostname: "example.com",
 				Path:     &Regexp{},
 			},
@@ -122,7 +139,7 @@ func Test_rule_matches(t *testing.T) {
 		},
 		{
 			name: "Hostname and nil path",
-			fields: fields{
+			rule: Rule{
 				Hostname: "example.com",
 				Path:     nil,
 			},
@@ -134,13 +151,8 @@ func Test_rule_matches(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			r := Rule{
-				Hostname: tt.fields.Hostname,
-				Path:     tt.fields.Path,
-				Service:  tt.fields.Service,
-			}
 			u := tt.args.requestURL
-			if got := r.Matches(u.Hostname(), u.Path); got != tt.want {
+			if got := tt.rule.Matches(u.Hostname(), u.Path); got != tt.want {
 				t.Errorf("rule.matches() = %v, want %v", got, tt.want)
 			}
 		})
@@ -182,25 +194,25 @@ func TestMarshalJSON(t *testing.T) {
 		{
 			name:     "Nil",
 			path:     nil,
-			expected: `{"hostname":"example.com","path":null,"service":"https://localhost:8000","originRequest":{"connectTimeout":30,"tlsTimeout":10,"tcpKeepAlive":30,"noHappyEyeballs":false,"keepAliveTimeout":90,"keepAliveConnections":100,"httpHostHeader":"","originServerName":"","caPool":"","noTLSVerify":false,"disableChunkedEncoding":false,"bastionMode":false,"proxyAddress":"127.0.0.1","proxyPort":0,"proxyType":"","ipRules":null,"http2Origin":false,"access":{"Enabled":false}}}`,
+			expected: `{"hostname":"example.com","path":null,"service":"https://localhost:8000","Handlers":null,"originRequest":{"connectTimeout":30,"tlsTimeout":10,"tcpKeepAlive":30,"noHappyEyeballs":false,"keepAliveTimeout":90,"keepAliveConnections":100,"httpHostHeader":"","originServerName":"","caPool":"","noTLSVerify":false,"disableChunkedEncoding":false,"bastionMode":false,"proxyAddress":"127.0.0.1","proxyPort":0,"proxyType":"","ipRules":null,"http2Origin":false,"access":{"teamName":"","audTag":null}}}`,
 			want:     true,
 		},
 		{
 			name:     "Nil regex",
 			path:     &Regexp{Regexp: nil},
-			expected: `{"hostname":"example.com","path":null,"service":"https://localhost:8000","originRequest":{"connectTimeout":30,"tlsTimeout":10,"tcpKeepAlive":30,"noHappyEyeballs":false,"keepAliveTimeout":90,"keepAliveConnections":100,"httpHostHeader":"","originServerName":"","caPool":"","noTLSVerify":false,"disableChunkedEncoding":false,"bastionMode":false,"proxyAddress":"127.0.0.1","proxyPort":0,"proxyType":"","ipRules":null,"http2Origin":false,"access":{"Enabled":false}}}`,
+			expected: `{"hostname":"example.com","path":null,"service":"https://localhost:8000","Handlers":null,"originRequest":{"connectTimeout":30,"tlsTimeout":10,"tcpKeepAlive":30,"noHappyEyeballs":false,"keepAliveTimeout":90,"keepAliveConnections":100,"httpHostHeader":"","originServerName":"","caPool":"","noTLSVerify":false,"disableChunkedEncoding":false,"bastionMode":false,"proxyAddress":"127.0.0.1","proxyPort":0,"proxyType":"","ipRules":null,"http2Origin":false,"access":{"teamName":"","audTag":null}}}`,
 			want:     true,
 		},
 		{
 			name:     "Empty",
 			path:     &Regexp{Regexp: regexp.MustCompile("")},
-			expected: `{"hostname":"example.com","path":"","service":"https://localhost:8000","originRequest":{"connectTimeout":30,"tlsTimeout":10,"tcpKeepAlive":30,"noHappyEyeballs":false,"keepAliveTimeout":90,"keepAliveConnections":100,"httpHostHeader":"","originServerName":"","caPool":"","noTLSVerify":false,"disableChunkedEncoding":false,"bastionMode":false,"proxyAddress":"127.0.0.1","proxyPort":0,"proxyType":"","ipRules":null,"http2Origin":false,"access":{"Enabled":false}}}`,
+			expected: `{"hostname":"example.com","path":"","service":"https://localhost:8000","Handlers":null,"originRequest":{"connectTimeout":30,"tlsTimeout":10,"tcpKeepAlive":30,"noHappyEyeballs":false,"keepAliveTimeout":90,"keepAliveConnections":100,"httpHostHeader":"","originServerName":"","caPool":"","noTLSVerify":false,"disableChunkedEncoding":false,"bastionMode":false,"proxyAddress":"127.0.0.1","proxyPort":0,"proxyType":"","ipRules":null,"http2Origin":false,"access":{"teamName":"","audTag":null}}}`,
 			want:     true,
 		},
 		{
 			name:     "Basic",
 			path:     &Regexp{Regexp: regexp.MustCompile("/echo")},
-			expected: `{"hostname":"example.com","path":"/echo","service":"https://localhost:8000","originRequest":{"connectTimeout":30,"tlsTimeout":10,"tcpKeepAlive":30,"noHappyEyeballs":false,"keepAliveTimeout":90,"keepAliveConnections":100,"httpHostHeader":"","originServerName":"","caPool":"","noTLSVerify":false,"disableChunkedEncoding":false,"bastionMode":false,"proxyAddress":"127.0.0.1","proxyPort":0,"proxyType":"","ipRules":null,"http2Origin":false,"access":{"Enabled":false}}}`,
+			expected: `{"hostname":"example.com","path":"/echo","service":"https://localhost:8000","Handlers":null,"originRequest":{"connectTimeout":30,"tlsTimeout":10,"tcpKeepAlive":30,"noHappyEyeballs":false,"keepAliveTimeout":90,"keepAliveConnections":100,"httpHostHeader":"","originServerName":"","caPool":"","noTLSVerify":false,"disableChunkedEncoding":false,"bastionMode":false,"proxyAddress":"127.0.0.1","proxyPort":0,"proxyType":"","ipRules":null,"http2Origin":false,"access":{"teamName":"","audTag":null}}}`,
 			want:     true,
 		},
 	}
@@ -27,10 +27,12 @@ type Orchestrator struct {
 	// Used by UpdateConfig to make sure one update at a time
 	lock sync.RWMutex
 	// Underlying value is proxy.Proxy, can be read without the lock, but still needs the lock to update
-	proxy  atomic.Value
-	config *Config
-	tags   []tunnelpogs.Tag
-	log    *zerolog.Logger
+	proxy atomic.Value
+	// TODO: TUN-6815 Use atomic.Bool once we upgrade to go 1.19. 1 Means enabled and 0 means disabled
+	warpRoutingEnabled uint32
+	config             *Config
+	tags               []tunnelpogs.Tag
+	log                *zerolog.Logger

 	// orchestrator must not handle any more updates after shutdownC is closed
 	shutdownC <-chan struct{}
@@ -122,6 +124,11 @@ func (o *Orchestrator) updateIngress(ingressRules ingress.Ingress, warpRouting i
 	o.proxy.Store(newProxy)
 	o.config.Ingress = &ingressRules
 	o.config.WarpRouting = warpRouting
+	if warpRouting.Enabled {
+		atomic.StoreUint32(&o.warpRoutingEnabled, 1)
+	} else {
+		atomic.StoreUint32(&o.warpRoutingEnabled, 0)
+	}

 	// If proxyShutdownC is nil, there is no previous running proxy
 	if o.proxyShutdownC != nil {
@@ -190,6 +197,14 @@ func (o *Orchestrator) GetOriginProxy() (connection.OriginProxy, error) {
 	return proxy, nil
 }

+// TODO: TUN-6815 consider storing WarpRouting.Enabled as atomic.Bool once we upgrade to go 1.19
+func (o *Orchestrator) WarpRoutingEnabled() (enabled bool) {
+	if atomic.LoadUint32(&o.warpRoutingEnabled) == 0 {
+		return false
+	}
+	return true
+}
+
 func (o *Orchestrator) waitToCloseLastProxy() {
 	<-o.shutdownC
 	o.lock.Lock()
@@ -55,6 +55,7 @@ func TestUpdateConfiguration(t *testing.T) {
 	initOriginProxy, err := orchestrator.GetOriginProxy()
 	require.NoError(t, err)
 	require.IsType(t, &proxy.Proxy{}, initOriginProxy)
+	require.False(t, orchestrator.WarpRoutingEnabled())

 	configJSONV2 := []byte(`
 {
@@ -122,6 +123,7 @@ func TestUpdateConfiguration(t *testing.T) {
 	require.Equal(t, false, configV2.Ingress.Rules[2].Config.NoTLSVerify)
 	require.Equal(t, true, configV2.Ingress.Rules[2].Config.NoHappyEyeballs)
 	require.True(t, configV2.WarpRouting.Enabled)
+	require.Equal(t, configV2.WarpRouting.Enabled, orchestrator.WarpRoutingEnabled())
 	require.Equal(t, configV2.WarpRouting.ConnectTimeout.Duration, 10*time.Second)

 	originProxyV2, err := orchestrator.GetOriginProxy()
@@ -166,6 +168,7 @@ func TestUpdateConfiguration(t *testing.T) {
 	require.True(t, configV10.Ingress.Rules[0].Matches("blogs.tunnel.io", "/2022/02/10"))
 	require.Equal(t, ingress.HelloWorldService, configV10.Ingress.Rules[0].Service.String())
 	require.False(t, configV10.WarpRouting.Enabled)
+	require.Equal(t, configV10.WarpRouting.Enabled, orchestrator.WarpRoutingEnabled())

 	originProxyV10, err := orchestrator.GetOriginProxy()
 	require.NoError(t, err)
@@ -152,6 +152,7 @@ func TestDecodeICMP(t *testing.T) {

 		require.Equal(t, test.packet.Type, icmpPacket.Type)
 		require.Equal(t, test.packet.Code, icmpPacket.Code)
+		assertICMPChecksum(t, icmpPacket)
 		require.Equal(t, test.packet.Body, icmpPacket.Body)
 		expectedBody, err := test.packet.Body.Marshal(test.packet.Type.Protocol())
 		require.NoError(t, err)
@@ -1,6 +1,7 @@
 package packet

 import (
+	"encoding/binary"
 	"fmt"
 	"net/netip"

@@ -21,6 +22,7 @@ const (
 	// 0 = ttl exceed in transit, 1 = fragment reassembly time exceeded
 	icmpTTLExceedInTransitCode       = 0
 	DefaultTTL                 uint8 = 255
+	pseudoHeaderLen                  = 40
 )

 // Packet represents an IP packet or a packet that is encapsulated by IP
@@ -117,7 +119,18 @@ func (i *ICMP) EncodeLayers() ([]gopacket.SerializableLayer, error) {
 		return nil, err
 	}

-	msg, err := i.Marshal(nil)
+	var serializedPsh []byte = nil
+	if i.Protocol == layers.IPProtocolICMPv6 {
+		psh := &PseudoHeader{
+			SrcIP: i.Src.As16(),
+			DstIP: i.Dst.As16(),
+			// i.Marshal re-calculates the UpperLayerPacketLength
+			UpperLayerPacketLength: 0,
+			NextHeader:             uint8(i.Protocol),
+		}
+		serializedPsh = psh.Marshal()
+	}
+	msg, err := i.Marshal(serializedPsh)
 	if err != nil {
 		return nil, err
 	}
@@ -125,6 +138,29 @@ func (i *ICMP) EncodeLayers() ([]gopacket.SerializableLayer, error) {
 	return append(ipLayers, icmpLayer), nil
 }

+// https://www.rfc-editor.org/rfc/rfc2460#section-8.1
+type PseudoHeader struct {
+	SrcIP                  [16]byte
+	DstIP                  [16]byte
+	UpperLayerPacketLength uint32
+	zero                   [3]byte
+	NextHeader             uint8
+}
+
+func (ph *PseudoHeader) Marshal() []byte {
+	buf := make([]byte, pseudoHeaderLen)
+	index := 0
+	copy(buf, ph.SrcIP[:])
+	index += 16
+	copy(buf[index:], ph.DstIP[:])
+	index += 16
+	binary.BigEndian.PutUint32(buf[index:], ph.UpperLayerPacketLength)
+	index += 4
+	copy(buf[index:], ph.zero[:])
+	buf[pseudoHeaderLen-1] = ph.NextHeader
+	return buf
+}
+
 func NewICMPTTLExceedPacket(originalIP *IP, originalPacket RawPacket, routerIP netip.Addr) *ICMP {
 	var (
 		protocol layers.IPProtocol
@@ -137,6 +173,7 @@ func NewICMPTTLExceedPacket(originalIP *IP, originalPacket RawPacket, routerIP n
 		protocol = layers.IPProtocolICMPv6
 		icmpType = ipv6.ICMPTypeTimeExceeded
 	}
+
 	return &ICMP{
 		IP: &IP{
 			Src:      routerIP,
@@ -5,6 +5,7 @@ import (
 	"net/netip"
 	"testing"

+	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/net/icmp"
@@ -101,4 +102,96 @@ func assertTTLExceedPacket(t *testing.T, pk *ICMP) {
 		require.Len(t, rawTTLExceedPacket.Data, headerLen+icmpHeaderLen+len(rawPacket.Data))
 		require.True(t, bytes.Equal(rawPacket.Data, rawTTLExceedPacket.Data[headerLen+icmpHeaderLen:]))
 	}
+
+	decoder := NewICMPDecoder()
+	decodedPacket, err := decoder.Decode(rawTTLExceedPacket)
+	require.NoError(t, err)
+	assertICMPChecksum(t, decodedPacket)
+}
+
+func assertICMPChecksum(t *testing.T, icmpPacket *ICMP) {
+	buf := gopacket.NewSerializeBuffer()
+	if icmpPacket.Protocol == layers.IPProtocolICMPv4 {
+		icmpv4 := layers.ICMPv4{
+			TypeCode: layers.CreateICMPv4TypeCode(uint8(icmpPacket.Type.(ipv4.ICMPType)), uint8(icmpPacket.Code)),
+		}
+		switch body := icmpPacket.Body.(type) {
+		case *icmp.Echo:
+			icmpv4.Id = uint16(body.ID)
+			icmpv4.Seq = uint16(body.Seq)
+			payload := gopacket.Payload(body.Data)
+			require.NoError(t, payload.SerializeTo(buf, serializeOpts))
+		default:
+			require.NoError(t, serializeICMPAsPayload(icmpPacket.Message, buf))
+		}
+		// SerializeTo sets the checksum in icmpv4
+		require.NoError(t, icmpv4.SerializeTo(buf, serializeOpts))
+		require.Equal(t, icmpv4.Checksum, uint16(icmpPacket.Checksum))
+	} else {
+		switch body := icmpPacket.Body.(type) {
+		case *icmp.Echo:
+			payload := gopacket.Payload(body.Data)
+			require.NoError(t, payload.SerializeTo(buf, serializeOpts))
+			echo := layers.ICMPv6Echo{
+				Identifier: uint16(body.ID),
+				SeqNumber:  uint16(body.Seq),
+			}
+			require.NoError(t, echo.SerializeTo(buf, serializeOpts))
+		default:
+			require.NoError(t, serializeICMPAsPayload(icmpPacket.Message, buf))
+		}
+
+		icmpv6 := layers.ICMPv6{
+			TypeCode: layers.CreateICMPv6TypeCode(uint8(icmpPacket.Type.(ipv6.ICMPType)), uint8(icmpPacket.Code)),
+		}
+		ipLayer := layers.IPv6{
+			Version:    6,
+			SrcIP:      icmpPacket.Src.AsSlice(),
+			DstIP:      icmpPacket.Dst.AsSlice(),
+			NextHeader: icmpPacket.Protocol,
+			HopLimit:   icmpPacket.TTL,
+		}
+		require.NoError(t, icmpv6.SetNetworkLayerForChecksum(&ipLayer))
+
+		// SerializeTo sets the checksum in icmpv4
+		require.NoError(t, icmpv6.SerializeTo(buf, serializeOpts))
+		require.Equal(t, icmpv6.Checksum, uint16(icmpPacket.Checksum))
+	}
+}
+
+func serializeICMPAsPayload(message *icmp.Message, buf gopacket.SerializeBuffer) error {
+	serializedBody, err := message.Body.Marshal(message.Type.Protocol())
+	if err != nil {
+		return err
+	}
+	payload := gopacket.Payload(serializedBody)
+	return payload.SerializeTo(buf, serializeOpts)
+}
+
+func TestChecksum(t *testing.T) {
+	data := []byte{0x63, 0x2c, 0x49, 0xd6, 0x00, 0x0d, 0xc1, 0xda}
+	pk := ICMP{
+		IP: &IP{
+			Src:      netip.MustParseAddr("2606:4700:110:89c1:c63a:861:e08c:b049"),
+			Dst:      netip.MustParseAddr("fde8:b693:d420:109b::2"),
+			Protocol: layers.IPProtocolICMPv6,
+			TTL:      3,
+		},
+		Message: &icmp.Message{
+			Type: ipv6.ICMPTypeEchoRequest,
+			Code: 0,
+			Body: &icmp.Echo{
+				ID:   0x20a7,
+				Seq:  8,
+				Data: data,
+			},
+		},
+	}
+	encoder := NewEncoder()
+	encoded, err := encoder.Encode(&pk)
+	require.NoError(t, err)
+
+	decoder := NewICMPDecoder()
+	decoded, err := decoder.Decode(encoded)
+	require.Equal(t, 0xff96, decoded.Checksum)
 }
@@ -2,23 +2,16 @@ package packet

 import (
 	"context"
-	"net"
 	"net/netip"

 	"github.com/rs/zerolog"
 )

-var (
-	// Source IP in documentation range to return ICMP error messages if we can't determine the IP of this machine
-	icmpv4ErrFallbackSrc = netip.MustParseAddr("192.0.2.30")
-	icmpv6ErrFallbackSrc = netip.MustParseAddr("2001:db8::")
-)
-
 // ICMPRouter sends ICMP messages and listens for their responses
 type ICMPRouter interface {
 	// Serve starts listening for responses to the requests until context is done
 	Serve(ctx context.Context) error
-	// Request sends an ICMP message
+	// Request sends an ICMP message. Implementations should not modify pk after the function returns.
 	Request(pk *ICMP, responder FunnelUniPipe) error
 }

@@ -28,33 +21,30 @@ type Upstream interface {
 	ReceivePacket(ctx context.Context) (RawPacket, error)
 }

+// Router routes packets between Upstream and ICMPRouter. Currently it rejects all other type of ICMP packets
 type Router struct {
-	upstream   Upstream
-	returnPipe FunnelUniPipe
-	icmpProxy  ICMPRouter
-	ipv4Src    netip.Addr
-	ipv6Src    netip.Addr
-	logger     *zerolog.Logger
+	upstream               Upstream
+	returnPipe             FunnelUniPipe
+	globalConfig           *GlobalRouterConfig
+	logger                 *zerolog.Logger
+	checkRouterEnabledFunc func() bool
 }

-func NewRouter(upstream Upstream, returnPipe FunnelUniPipe, icmpProxy ICMPRouter, logger *zerolog.Logger) *Router {
-	ipv4Src, err := findLocalAddr(net.ParseIP("1.1.1.1"), 53)
-	if err != nil {
-		logger.Warn().Err(err).Msgf("Failed to determine the IPv4 for this machine. It will use %s as source IP for error messages such as ICMP TTL exceed", icmpv4ErrFallbackSrc)
-		ipv4Src = icmpv4ErrFallbackSrc
-	}
-	ipv6Src, err := findLocalAddr(net.ParseIP("2606:4700:4700::1111"), 53)
-	if err != nil {
-		logger.Warn().Err(err).Msgf("Failed to determine the IPv6 for this machine. It will use %s as source IP for error messages such as ICMP TTL exceed", icmpv6ErrFallbackSrc)
-		ipv6Src = icmpv6ErrFallbackSrc
-	}
+// GlobalRouterConfig is the configuration shared by all instance of Router.
+type GlobalRouterConfig struct {
+	ICMPRouter ICMPRouter
+	IPv4Src    netip.Addr
+	IPv6Src    netip.Addr
+	Zone       string
+}
+
+func NewRouter(globalConfig *GlobalRouterConfig, upstream Upstream, returnPipe FunnelUniPipe, logger *zerolog.Logger, checkRouterEnabledFunc func() bool) *Router {
 	return &Router{
-		upstream:   upstream,
-		returnPipe: returnPipe,
-		icmpProxy:  icmpProxy,
-		ipv4Src:    ipv4Src,
-		ipv6Src:    ipv6Src,
-		logger:     logger,
+		upstream:               upstream,
+		returnPipe:             returnPipe,
+		globalConfig:           globalConfig,
+		logger:                 logger,
+		checkRouterEnabledFunc: checkRouterEnabledFunc,
 	}
 }

@@ -66,6 +56,16 @@ func (r *Router) Serve(ctx context.Context) error {
 		if err != nil {
 			return err
 		}
+
+		// Drop packets if ICMPRouter wasn't created
+		if r.globalConfig == nil {
+			continue
+		}
+
+		if enabled := r.checkRouterEnabledFunc(); !enabled {
+			continue
+		}
+
 		icmpPacket, err := icmpDecoder.Decode(rawPacket)
 		if err != nil {
 			r.logger.Err(err).Msg("Failed to decode ICMP packet from quic datagram")
@@ -80,7 +80,7 @@ func (r *Router) Serve(ctx context.Context) error {
 		}
 		icmpPacket.TTL--

-		if err := r.icmpProxy.Request(icmpPacket, r.returnPipe); err != nil {
+		if err := r.globalConfig.ICMPRouter.Request(icmpPacket, r.returnPipe); err != nil {
 			r.logger.Err(err).
 				Str("src", icmpPacket.Src.String()).
 				Str("dst", icmpPacket.Dst.String()).
@@ -94,9 +94,9 @@ func (r *Router) Serve(ctx context.Context) error {
 func (r *Router) sendTTLExceedMsg(pk *ICMP, rawPacket RawPacket, encoder *Encoder) error {
 	var srcIP netip.Addr
 	if pk.Dst.Is4() {
-		srcIP = r.ipv4Src
+		srcIP = r.globalConfig.IPv4Src
 	} else {
-		srcIP = r.ipv6Src
+		srcIP = r.globalConfig.IPv6Src
 	}
 	ttlExceedPacket := NewICMPTTLExceedPacket(pk.IP, rawPacket, srcIP)

@@ -106,21 +106,3 @@ func (r *Router) sendTTLExceedMsg(pk *ICMP, rawPacket RawPacket, encoder *Encode
 	}
 	return r.returnPipe.SendPacket(pk.Src, encodedTTLExceed)
 }
-
-// findLocalAddr tries to dial UDP and returns the local address picked by the OS
-func findLocalAddr(dst net.IP, port int) (netip.Addr, error) {
-	udpConn, err := net.DialUDP("udp", nil, &net.UDPAddr{
-		IP:   dst,
-		Port: port,
-	})
-	if err != nil {
-		return netip.Addr{}, err
-	}
-	defer udpConn.Close()
-	localAddrPort, err := netip.ParseAddrPort(udpConn.LocalAddr().String())
-	if err != nil {
-		return netip.Addr{}, err
-	}
-	localAddr := localAddrPort.Addr()
-	return localAddr, nil
-}
@@ -5,7 +5,9 @@ import (
 	"context"
 	"fmt"
 	"net/netip"
+	"sync/atomic"
 	"testing"
+	"time"

 	"github.com/google/gopacket/layers"
 	"github.com/rs/zerolog"
@@ -16,7 +18,12 @@ import (
 )

 var (
-	noopLogger = zerolog.Nop()
+	noopLogger   = zerolog.Nop()
+	packetConfig = &GlobalRouterConfig{
+		ICMPRouter: &mockICMPRouter{},
+		IPv4Src:    netip.MustParseAddr("172.16.0.1"),
+		IPv6Src:    netip.MustParseAddr("fd51:2391:523:f4ee::1"),
+	}
 )

 func TestRouterReturnTTLExceed(t *testing.T) {
@@ -26,7 +33,9 @@ func TestRouterReturnTTLExceed(t *testing.T) {
 	returnPipe := &mockFunnelUniPipe{
 		uniPipe: make(chan RawPacket),
 	}
-	router := NewRouter(upstream, returnPipe, &mockICMPRouter{}, &noopLogger)
+	routerEnabled := &routerEnabledChecker{}
+	routerEnabled.set(true)
+	router := NewRouter(packetConfig, upstream, returnPipe, &noopLogger, routerEnabled.isEnabled)
 	ctx, cancel := context.WithCancel(context.Background())
 	routerStopped := make(chan struct{})
 	go func() {
@@ -51,7 +60,7 @@ func TestRouterReturnTTLExceed(t *testing.T) {
 			},
 		},
 	}
-	assertTTLExceed(t, &pk, router.ipv4Src, upstream, returnPipe)
+	assertTTLExceed(t, &pk, router.globalConfig.IPv4Src, upstream, returnPipe)
 	pk = ICMP{
 		IP: &IP{
 			Src:      netip.MustParseAddr("fd51:2391:523:f4ee::1"),
@@ -69,7 +78,66 @@ func TestRouterReturnTTLExceed(t *testing.T) {
 			},
 		},
 	}
-	assertTTLExceed(t, &pk, router.ipv6Src, upstream, returnPipe)
+	assertTTLExceed(t, &pk, router.globalConfig.IPv6Src, upstream, returnPipe)
+
+	cancel()
+	<-routerStopped
+}
+
+func TestRouterCheckEnabled(t *testing.T) {
+	upstream := &mockUpstream{
+		source: make(chan RawPacket),
+	}
+	returnPipe := &mockFunnelUniPipe{
+		uniPipe: make(chan RawPacket),
+	}
+	routerEnabled := &routerEnabledChecker{}
+	router := NewRouter(packetConfig, upstream, returnPipe, &noopLogger, routerEnabled.isEnabled)
+	ctx, cancel := context.WithCancel(context.Background())
+	routerStopped := make(chan struct{})
+	go func() {
+		router.Serve(ctx)
+		close(routerStopped)
+	}()
+
+	pk := ICMP{
+		IP: &IP{
+			Src:      netip.MustParseAddr("192.168.1.1"),
+			Dst:      netip.MustParseAddr("10.0.0.1"),
+			Protocol: layers.IPProtocolICMPv4,
+			TTL:      1,
+		},
+		Message: &icmp.Message{
+			Type: ipv4.ICMPTypeEcho,
+			Code: 0,
+			Body: &icmp.Echo{
+				ID:   12481,
+				Seq:  8036,
+				Data: []byte(t.Name()),
+			},
+		},
+	}
+
+	// router is disabled
+	require.NoError(t, upstream.send(&pk))
+	select {
+	case <-time.After(time.Millisecond * 10):
+	case <-returnPipe.uniPipe:
+		t.Error("Unexpected reply when router is disabled")
+	}
+	routerEnabled.set(true)
+	// router is enabled, expects reply
+	require.NoError(t, upstream.send(&pk))
+	<-returnPipe.uniPipe
+
+	routerEnabled.set(false)
+	// router is disabled
+	require.NoError(t, upstream.send(&pk))
+	select {
+	case <-time.After(time.Millisecond * 10):
+	case <-returnPipe.uniPipe:
+		t.Error("Unexpected reply when router is disabled")
+	}

 	cancel()
 	<-routerStopped
@@ -79,8 +147,8 @@ func assertTTLExceed(t *testing.T, originalPacket *ICMP, expectedSrc netip.Addr,
 	encoder := NewEncoder()
 	rawPacket, err := encoder.Encode(originalPacket)
 	require.NoError(t, err)
-
 	upstream.source <- rawPacket
+
 	resp := <-returnPipe.uniPipe
 	decoder := NewICMPDecoder()
 	decoded, err := decoder.Decode(resp)
@@ -96,6 +164,7 @@ func assertTTLExceed(t *testing.T, originalPacket *ICMP, expectedSrc netip.Addr,
 		require.Equal(t, ipv6.ICMPTypeTimeExceeded, decoded.Type)
 	}
 	require.Equal(t, 0, decoded.Code)
+	assertICMPChecksum(t, decoded)
 	timeExceed, ok := decoded.Body.(*icmp.TimeExceeded)
 	require.True(t, ok)
 	require.True(t, bytes.Equal(rawPacket.Data, timeExceed.Data))
@@ -105,6 +174,16 @@ type mockUpstream struct {
 	source chan RawPacket
 }

+func (ms *mockUpstream) send(pk Packet) error {
+	encoder := NewEncoder()
+	rawPacket, err := encoder.Encode(pk)
+	if err != nil {
+		return err
+	}
+	ms.source <- rawPacket
+	return nil
+}
+
 func (ms *mockUpstream) ReceivePacket(ctx context.Context) (RawPacket, error) {
 	select {
 	case <-ctx.Done():
@@ -123,3 +202,22 @@ func (mir mockICMPRouter) Serve(ctx context.Context) error {
 func (mir mockICMPRouter) Request(pk *ICMP, responder FunnelUniPipe) error {
 	return fmt.Errorf("Request not implemented by mockICMPRouter")
 }
+
+type routerEnabledChecker struct {
+	enabled uint32
+}
+
+func (rec *routerEnabledChecker) isEnabled() bool {
+	if atomic.LoadUint32(&rec.enabled) == 0 {
+		return false
+	}
+	return true
+}
+
+func (rec *routerEnabledChecker) set(enabled bool) {
+	if enabled {
+		atomic.StoreUint32(&rec.enabled, 1)
+	} else {
+		atomic.StoreUint32(&rec.enabled, 0)
+	}
+}
@@ -60,6 +60,21 @@ func NewOriginProxy(
 	return proxy
 }

+func (p *Proxy) applyIngressMiddleware(rule *ingress.Rule, r *http.Request, w connection.ResponseWriter) (error, bool) {
+	for _, handler := range rule.Handlers {
+		result, err := handler.Handle(r.Context(), r)
+		if err != nil {
+			return errors.Wrap(err, fmt.Sprintf("error while processing middleware handler %s", handler.Name())), false
+		}
+
+		if result.ShouldFilterRequest {
+			w.WriteRespHeaders(result.StatusCode, nil)
+			return fmt.Errorf("request filtered by middleware handler (%s) due to: %s", handler.Name(), result.Reason), true
+		}
+	}
+	return nil, true
+}
+
 // ProxyHTTP further depends on ingress rules to establish a connection with the origin service. This may be
 // a simple roundtrip or a tcp/websocket dial depending on ingres rule setup.
 func (p *Proxy) ProxyHTTP(
@@ -86,6 +101,13 @@ func (p *Proxy) ProxyHTTP(
 	p.logRequest(req, logFields)
 	ruleSpan.SetAttributes(attribute.Int("rule-num", ruleNum))
 	ruleSpan.End()
+	if err, applied := p.applyIngressMiddleware(rule, req, w); err != nil {
+		if applied {
+			p.log.Error().Msg(err.Error())
+			return nil
+		}
+		return err
+	}

 	switch originProxy := rule.Service.(type) {
 	case ingress.HTTPOriginProxy:
@@ -49,7 +49,7 @@ func (dm *DatagramMuxer) SendToSession(session *packet.Session) error {
 		packetTooBigDropped.Inc()
 		return fmt.Errorf("origin UDP payload has %d bytes, which exceeds transport MTU %d", len(session.Payload), dm.mtu())
 	}
-	payloadWithMetadata, err := suffixSessionID(session.ID, session.Payload)
+	payloadWithMetadata, err := SuffixSessionID(session.ID, session.Payload)
 	if err != nil {
 		return errors.Wrap(err, "Failed to suffix session ID to datagram, it will be dropped")
 	}
@@ -112,7 +112,7 @@ func extractSessionID(b []byte) (uuid.UUID, []byte, error) {

 // SuffixSessionID appends the session ID at the end of the payload. Suffix is more performant than prefix because
 // the payload slice might already have enough capacity to append the session ID at the end
-func suffixSessionID(sessionID uuid.UUID, b []byte) ([]byte, error) {
+func SuffixSessionID(sessionID uuid.UUID, b []byte) ([]byte, error) {
 	if len(b)+len(sessionID) > MaxDatagramFrameSize {
 		return nil, fmt.Errorf("datagram size exceed %d", MaxDatagramFrameSize)
 	}
@@ -31,7 +31,7 @@ var (

 func TestSuffixThenRemoveSessionID(t *testing.T) {
 	msg := []byte(t.Name())
-	msgWithID, err := suffixSessionID(testSessionID, msg)
+	msgWithID, err := SuffixSessionID(testSessionID, msg)
 	require.NoError(t, err)
 	require.Len(t, msgWithID, len(msg)+sessionIDLen)

@@ -50,11 +50,11 @@ func TestRemoveSessionIDError(t *testing.T) {

 func TestSuffixSessionIDError(t *testing.T) {
 	msg := make([]byte, MaxDatagramFrameSize-sessionIDLen)
-	_, err := suffixSessionID(testSessionID, msg)
+	_, err := SuffixSessionID(testSessionID, msg)
 	require.NoError(t, err)

 	msg = make([]byte, MaxDatagramFrameSize-sessionIDLen+1)
-	_, err = suffixSessionID(testSessionID, msg)
+	_, err = SuffixSessionID(testSessionID, msg)
 	require.Error(t, err)
 }

@@ -11,11 +11,11 @@ import (
 	"github.com/cloudflare/cloudflared/packet"
 )

-type datagramV2Type byte
+type DatagramV2Type byte

 const (
-	udp datagramV2Type = iota
-	ip
+	DatagramTypeUDP DatagramV2Type = iota
+	DatagramTypeIP
 )

 const (
@@ -24,7 +24,7 @@ const (
 	packetChanCapacity = 128
 )

-func suffixType(b []byte, datagramType datagramV2Type) ([]byte, error) {
+func SuffixType(b []byte, datagramType DatagramV2Type) ([]byte, error) {
 	if len(b)+typeIDLen > MaxDatagramFrameSize {
 		return nil, fmt.Errorf("datagram size %d exceeds max frame size %d", len(b), MaxDatagramFrameSize)
 	}
@@ -65,11 +65,11 @@ func (dm *DatagramMuxerV2) SendToSession(session *packet.Session) error {
 		packetTooBigDropped.Inc()
 		return fmt.Errorf("origin UDP payload has %d bytes, which exceeds transport MTU %d", len(session.Payload), dm.mtu())
 	}
-	msgWithID, err := suffixSessionID(session.ID, session.Payload)
+	msgWithID, err := SuffixSessionID(session.ID, session.Payload)
 	if err != nil {
 		return errors.Wrap(err, "Failed to suffix session ID to datagram, it will be dropped")
 	}
-	msgWithIDAndType, err := suffixType(msgWithID, udp)
+	msgWithIDAndType, err := SuffixType(msgWithID, DatagramTypeUDP)
 	if err != nil {
 		return errors.Wrap(err, "Failed to suffix datagram type, it will be dropped")
 	}
@@ -82,7 +82,7 @@ func (dm *DatagramMuxerV2) SendToSession(session *packet.Session) error {
 // SendPacket suffix the datagram type to the packet. The other end of the QUIC connection can demultiplex by parsing
 // the payload as IP and look at the source and destination.
 func (dm *DatagramMuxerV2) SendPacket(pk packet.RawPacket) error {
-	payloadWithVersion, err := suffixType(pk.Data, ip)
+	payloadWithVersion, err := SuffixType(pk.Data, DatagramTypeIP)
 	if err != nil {
 		return errors.Wrap(err, "Failed to suffix datagram type, it will be dropped")
 	}
@@ -121,12 +121,12 @@ func (dm *DatagramMuxerV2) demux(ctx context.Context, msgWithType []byte) error
 	if len(msgWithType) < typeIDLen {
 		return fmt.Errorf("QUIC datagram should have at least %d byte", typeIDLen)
 	}
-	msgType := datagramV2Type(msgWithType[len(msgWithType)-typeIDLen])
+	msgType := DatagramV2Type(msgWithType[len(msgWithType)-typeIDLen])
 	msg := msgWithType[0 : len(msgWithType)-typeIDLen]
 	switch msgType {
-	case udp:
+	case DatagramTypeUDP:
 		return dm.handleSession(ctx, msg)
-	case ip:
+	case DatagramTypeIP:
 		return dm.handlePacket(ctx, msg)
 	default:
 		return fmt.Errorf("Unexpected datagram type %d", msgType)
@@ -16,7 +16,6 @@ import (
 	"github.com/cloudflare/cloudflared/edgediscovery"
 	"github.com/cloudflare/cloudflared/edgediscovery/allregions"
 	"github.com/cloudflare/cloudflared/h2mux"
-	"github.com/cloudflare/cloudflared/ingress"
 	"github.com/cloudflare/cloudflared/orchestration"
 	"github.com/cloudflare/cloudflared/retry"
 	"github.com/cloudflare/cloudflared/signal"
@@ -117,13 +116,6 @@ func NewSupervisor(config *TunnelConfig, orchestrator *orchestration.Orchestrato
 		connAwareLogger:   log,
 	}

-	icmpRouter, err := ingress.NewICMPRouter(config.Log)
-	if err != nil {
-		log.Logger().Warn().Err(err).Msg("Failed to create icmp router, ICMP proxy feature is disabled")
-	} else {
-		edgeTunnelServer.icmpRouter = icmpRouter
-	}
-
 	useReconnectToken := false
 	if config.ClassicTunnel != nil {
 		useReconnectToken = config.ClassicTunnel.UseReconnectToken
@@ -151,9 +143,9 @@ func (s *Supervisor) Run(
 	ctx context.Context,
 	connectedSignal *signal.Signal,
 ) error {
-	if s.edgeTunnelServer.icmpRouter != nil {
+	if s.config.PacketConfig != nil {
 		go func() {
-			if err := s.edgeTunnelServer.icmpRouter.Serve(ctx); err != nil {
+			if err := s.config.PacketConfig.ICMPRouter.Serve(ctx); err != nil {
 				if errors.Is(err, net.ErrClosed) {
 					s.log.Logger().Info().Err(err).Msg("icmp router terminated")
 				} else {
@@ -70,6 +70,7 @@ type TunnelConfig struct {
 	MuxerConfig      *connection.MuxerConfig
 	ProtocolSelector connection.ProtocolSelector
 	EdgeTLSConfigs   map[connection.Protocol]*tls.Config
+	PacketConfig     *packet.GlobalRouterConfig
 }

 func (c *TunnelConfig) registrationOptions(connectionID uint8, OriginLocalIP string, uuid uuid.UUID) *tunnelpogs.RegistrationOptions {
@@ -200,7 +201,6 @@ type EdgeTunnelServer struct {
 	reconnectCh       chan ReconnectSignal
 	gracefulShutdownC <-chan struct{}
 	tracker           *tunnelstate.ConnTracker
-	icmpRouter        packet.ICMPRouter

 	connAwareLogger *ConnAwareLogger
 }
@@ -661,7 +661,7 @@ func (e *EdgeTunnelServer) serveQUIC(
 		connOptions,
 		controlStreamHandler,
 		connLogger.Logger(),
-		e.icmpRouter)
+		e.config.PacketConfig)
 	if err != nil {
 		if e.config.NeedPQ {
 			handlePQTunnelError(err, e.config)
@@ -0,0 +1,202 @@
+Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
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+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
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+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
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+      form, that is based on (or derived from) the Work and for which the
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+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
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+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
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+      on behalf of whom a Contribution has been received by Licensor and
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+          notices within Derivative Works that You distribute, alongside
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+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
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+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
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+      Work (including but not limited to damages for loss of goodwill,
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+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "{}"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright {yyyy} {name of copyright owner}
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
@@ -0,0 +1,5 @@
+CoreOS Project
+Copyright 2014 CoreOS, Inc
+
+This product includes software developed at CoreOS, Inc.
+(http://www.coreos.com/).
@@ -0,0 +1,16 @@
+package oidc
+
+// JOSE asymmetric signing algorithm values as defined by RFC 7518
+//
+// see: https://tools.ietf.org/html/rfc7518#section-3.1
+const (
+	RS256 = "RS256" // RSASSA-PKCS-v1.5 using SHA-256
+	RS384 = "RS384" // RSASSA-PKCS-v1.5 using SHA-384
+	RS512 = "RS512" // RSASSA-PKCS-v1.5 using SHA-512
+	ES256 = "ES256" // ECDSA using P-256 and SHA-256
+	ES384 = "ES384" // ECDSA using P-384 and SHA-384
+	ES512 = "ES512" // ECDSA using P-521 and SHA-512
+	PS256 = "PS256" // RSASSA-PSS using SHA256 and MGF1-SHA256
+	PS384 = "PS384" // RSASSA-PSS using SHA384 and MGF1-SHA384
+	PS512 = "PS512" // RSASSA-PSS using SHA512 and MGF1-SHA512
+)
@@ -0,0 +1,248 @@
+package oidc
+
+import (
+	"context"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"sync"
+	"time"
+
+	jose "gopkg.in/square/go-jose.v2"
+)
+
+// StaticKeySet is a verifier that validates JWT against a static set of public keys.
+type StaticKeySet struct {
+	// PublicKeys used to verify the JWT. Supported types are *rsa.PublicKey and
+	// *ecdsa.PublicKey.
+	PublicKeys []crypto.PublicKey
+}
+
+// VerifySignature compares the signature against a static set of public keys.
+func (s *StaticKeySet) VerifySignature(ctx context.Context, jwt string) ([]byte, error) {
+	jws, err := jose.ParseSigned(jwt)
+	if err != nil {
+		return nil, fmt.Errorf("parsing jwt: %v", err)
+	}
+	for _, pub := range s.PublicKeys {
+		switch pub.(type) {
+		case *rsa.PublicKey:
+		case *ecdsa.PublicKey:
+		default:
+			return nil, fmt.Errorf("invalid public key type provided: %T", pub)
+		}
+		payload, err := jws.Verify(pub)
+		if err != nil {
+			continue
+		}
+		return payload, nil
+	}
+	return nil, fmt.Errorf("no public keys able to verify jwt")
+}
+
+// NewRemoteKeySet returns a KeySet that can validate JSON web tokens by using HTTP
+// GETs to fetch JSON web token sets hosted at a remote URL. This is automatically
+// used by NewProvider using the URLs returned by OpenID Connect discovery, but is
+// exposed for providers that don't support discovery or to prevent round trips to the
+// discovery URL.
+//
+// The returned KeySet is a long lived verifier that caches keys based on any
+// keys change. Reuse a common remote key set instead of creating new ones as needed.
+func NewRemoteKeySet(ctx context.Context, jwksURL string) *RemoteKeySet {
+	return newRemoteKeySet(ctx, jwksURL, time.Now)
+}
+
+func newRemoteKeySet(ctx context.Context, jwksURL string, now func() time.Time) *RemoteKeySet {
+	if now == nil {
+		now = time.Now
+	}
+	return &RemoteKeySet{jwksURL: jwksURL, ctx: cloneContext(ctx), now: now}
+}
+
+// RemoteKeySet is a KeySet implementation that validates JSON web tokens against
+// a jwks_uri endpoint.
+type RemoteKeySet struct {
+	jwksURL string
+	ctx     context.Context
+	now     func() time.Time
+
+	// guard all other fields
+	mu sync.RWMutex
+
+	// inflight suppresses parallel execution of updateKeys and allows
+	// multiple goroutines to wait for its result.
+	inflight *inflight
+
+	// A set of cached keys.
+	cachedKeys []jose.JSONWebKey
+}
+
+// inflight is used to wait on some in-flight request from multiple goroutines.
+type inflight struct {
+	doneCh chan struct{}
+
+	keys []jose.JSONWebKey
+	err  error
+}
+
+func newInflight() *inflight {
+	return &inflight{doneCh: make(chan struct{})}
+}
+
+// wait returns a channel that multiple goroutines can receive on. Once it returns
+// a value, the inflight request is done and result() can be inspected.
+func (i *inflight) wait() <-chan struct{} {
+	return i.doneCh
+}
+
+// done can only be called by a single goroutine. It records the result of the
+// inflight request and signals other goroutines that the result is safe to
+// inspect.
+func (i *inflight) done(keys []jose.JSONWebKey, err error) {
+	i.keys = keys
+	i.err = err
+	close(i.doneCh)
+}
+
+// result cannot be called until the wait() channel has returned a value.
+func (i *inflight) result() ([]jose.JSONWebKey, error) {
+	return i.keys, i.err
+}
+
+// paresdJWTKey is a context key that allows common setups to avoid parsing the
+// JWT twice. It holds a *jose.JSONWebSignature value.
+var parsedJWTKey contextKey
+
+// VerifySignature validates a payload against a signature from the jwks_uri.
+//
+// Users MUST NOT call this method directly and should use an IDTokenVerifier
+// instead. This method skips critical validations such as 'alg' values and is
+// only exported to implement the KeySet interface.
+func (r *RemoteKeySet) VerifySignature(ctx context.Context, jwt string) ([]byte, error) {
+	jws, ok := ctx.Value(parsedJWTKey).(*jose.JSONWebSignature)
+	if !ok {
+		var err error
+		jws, err = jose.ParseSigned(jwt)
+		if err != nil {
+			return nil, fmt.Errorf("oidc: malformed jwt: %v", err)
+		}
+	}
+	return r.verify(ctx, jws)
+}
+
+func (r *RemoteKeySet) verify(ctx context.Context, jws *jose.JSONWebSignature) ([]byte, error) {
+	// We don't support JWTs signed with multiple signatures.
+	keyID := ""
+	for _, sig := range jws.Signatures {
+		keyID = sig.Header.KeyID
+		break
+	}
+
+	keys := r.keysFromCache()
+	for _, key := range keys {
+		if keyID == "" || key.KeyID == keyID {
+			if payload, err := jws.Verify(&key); err == nil {
+				return payload, nil
+			}
+		}
+	}
+
+	// If the kid doesn't match, check for new keys from the remote. This is the
+	// strategy recommended by the spec.
+	//
+	// https://openid.net/specs/openid-connect-core-1_0.html#RotateSigKeys
+	keys, err := r.keysFromRemote(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("fetching keys %v", err)
+	}
+
+	for _, key := range keys {
+		if keyID == "" || key.KeyID == keyID {
+			if payload, err := jws.Verify(&key); err == nil {
+				return payload, nil
+			}
+		}
+	}
+	return nil, errors.New("failed to verify id token signature")
+}
+
+func (r *RemoteKeySet) keysFromCache() (keys []jose.JSONWebKey) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	return r.cachedKeys
+}
+
+// keysFromRemote syncs the key set from the remote set, records the values in the
+// cache, and returns the key set.
+func (r *RemoteKeySet) keysFromRemote(ctx context.Context) ([]jose.JSONWebKey, error) {
+	// Need to lock to inspect the inflight request field.
+	r.mu.Lock()
+	// If there's not a current inflight request, create one.
+	if r.inflight == nil {
+		r.inflight = newInflight()
+
+		// This goroutine has exclusive ownership over the current inflight
+		// request. It releases the resource by nil'ing the inflight field
+		// once the goroutine is done.
+		go func() {
+			// Sync keys and finish inflight when that's done.
+			keys, err := r.updateKeys()
+
+			r.inflight.done(keys, err)
+
+			// Lock to update the keys and indicate that there is no longer an
+			// inflight request.
+			r.mu.Lock()
+			defer r.mu.Unlock()
+
+			if err == nil {
+				r.cachedKeys = keys
+			}
+
+			// Free inflight so a different request can run.
+			r.inflight = nil
+		}()
+	}
+	inflight := r.inflight
+	r.mu.Unlock()
+
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case <-inflight.wait():
+		return inflight.result()
+	}
+}
+
+func (r *RemoteKeySet) updateKeys() ([]jose.JSONWebKey, error) {
+	req, err := http.NewRequest("GET", r.jwksURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("oidc: can't create request: %v", err)
+	}
+
+	resp, err := doRequest(r.ctx, req)
+	if err != nil {
+		return nil, fmt.Errorf("oidc: get keys failed %v", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("unable to read response body: %v", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("oidc: get keys failed: %s %s", resp.Status, body)
+	}
+
+	var keySet jose.JSONWebKeySet
+	err = unmarshalResp(resp, body, &keySet)
+	if err != nil {
+		return nil, fmt.Errorf("oidc: failed to decode keys: %v %s", err, body)
+	}
+	return keySet.Keys, nil
+}
@@ -0,0 +1,522 @@
+// Package oidc implements OpenID Connect client logic for the golang.org/x/oauth2 package.
+package oidc
+
+import (
+	"context"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"hash"
+	"io/ioutil"
+	"mime"
+	"net/http"
+	"strings"
+	"time"
+
+	"golang.org/x/oauth2"
+)
+
+const (
+	// ScopeOpenID is the mandatory scope for all OpenID Connect OAuth2 requests.
+	ScopeOpenID = "openid"
+
+	// ScopeOfflineAccess is an optional scope defined by OpenID Connect for requesting
+	// OAuth2 refresh tokens.
+	//
+	// Support for this scope differs between OpenID Connect providers. For instance
+	// Google rejects it, favoring appending "access_type=offline" as part of the
+	// authorization request instead.
+	//
+	// See: https://openid.net/specs/openid-connect-core-1_0.html#OfflineAccess
+	ScopeOfflineAccess = "offline_access"
+)
+
+var (
+	errNoAtHash      = errors.New("id token did not have an access token hash")
+	errInvalidAtHash = errors.New("access token hash does not match value in ID token")
+)
+
+type contextKey int
+
+var issuerURLKey contextKey
+
+// ClientContext returns a new Context that carries the provided HTTP client.
+//
+// This method sets the same context key used by the golang.org/x/oauth2 package,
+// so the returned context works for that package too.
+//
+//    myClient := &http.Client{}
+//    ctx := oidc.ClientContext(parentContext, myClient)
+//
+//    // This will use the custom client
+//    provider, err := oidc.NewProvider(ctx, "https://accounts.example.com")
+//
+func ClientContext(ctx context.Context, client *http.Client) context.Context {
+	return context.WithValue(ctx, oauth2.HTTPClient, client)
+}
+
+// cloneContext copies a context's bag-of-values into a new context that isn't
+// associated with its cancellation. This is used to initialize remote keys sets
+// which run in the background and aren't associated with the initial context.
+func cloneContext(ctx context.Context) context.Context {
+	cp := context.Background()
+	if c, ok := ctx.Value(oauth2.HTTPClient).(*http.Client); ok {
+		cp = ClientContext(cp, c)
+	}
+	return cp
+}
+
+// InsecureIssuerURLContext allows discovery to work when the issuer_url reported
+// by upstream is mismatched with the discovery URL. This is meant for integration
+// with off-spec providers such as Azure.
+//
+//    discoveryBaseURL := "https://login.microsoftonline.com/organizations/v2.0"
+//    issuerURL := "https://login.microsoftonline.com/my-tenantid/v2.0"
+//
+//    ctx := oidc.InsecureIssuerURLContext(parentContext, issuerURL)
+//
+//    // Provider will be discovered with the discoveryBaseURL, but use issuerURL
+//    // for future issuer validation.
+//    provider, err := oidc.NewProvider(ctx, discoveryBaseURL)
+//
+// This is insecure because validating the correct issuer is critical for multi-tenant
+// proivders. Any overrides here MUST be carefully reviewed.
+func InsecureIssuerURLContext(ctx context.Context, issuerURL string) context.Context {
+	return context.WithValue(ctx, issuerURLKey, issuerURL)
+}
+
+func doRequest(ctx context.Context, req *http.Request) (*http.Response, error) {
+	client := http.DefaultClient
+	if c, ok := ctx.Value(oauth2.HTTPClient).(*http.Client); ok {
+		client = c
+	}
+	return client.Do(req.WithContext(ctx))
+}
+
+// Provider represents an OpenID Connect server's configuration.
+type Provider struct {
+	issuer      string
+	authURL     string
+	tokenURL    string
+	userInfoURL string
+	algorithms  []string
+
+	// Raw claims returned by the server.
+	rawClaims []byte
+
+	remoteKeySet KeySet
+}
+
+type providerJSON struct {
+	Issuer      string   `json:"issuer"`
+	AuthURL     string   `json:"authorization_endpoint"`
+	TokenURL    string   `json:"token_endpoint"`
+	JWKSURL     string   `json:"jwks_uri"`
+	UserInfoURL string   `json:"userinfo_endpoint"`
+	Algorithms  []string `json:"id_token_signing_alg_values_supported"`
+}
+
+// supportedAlgorithms is a list of algorithms explicitly supported by this
+// package. If a provider supports other algorithms, such as HS256 or none,
+// those values won't be passed to the IDTokenVerifier.
+var supportedAlgorithms = map[string]bool{
+	RS256: true,
+	RS384: true,
+	RS512: true,
+	ES256: true,
+	ES384: true,
+	ES512: true,
+	PS256: true,
+	PS384: true,
+	PS512: true,
+}
+
+// ProviderConfig allows creating providers when discovery isn't supported. It's
+// generally easier to use NewProvider directly.
+type ProviderConfig struct {
+	// IssuerURL is the identity of the provider, and the string it uses to sign
+	// ID tokens with. For example "https://accounts.google.com". This value MUST
+	// match ID tokens exactly.
+	IssuerURL string
+	// AuthURL is the endpoint used by the provider to support the OAuth 2.0
+	// authorization endpoint.
+	AuthURL string
+	// TokenURL is the endpoint used by the provider to support the OAuth 2.0
+	// token endpoint.
+	TokenURL string
+	// UserInfoURL is the endpoint used by the provider to support the OpenID
+	// Connect UserInfo flow.
+	//
+	// https://openid.net/specs/openid-connect-core-1_0.html#UserInfo
+	UserInfoURL string
+	// JWKSURL is the endpoint used by the provider to advertise public keys to
+	// verify issued ID tokens. This endpoint is polled as new keys are made
+	// available.
+	JWKSURL string
+
+	// Algorithms, if provided, indicate a list of JWT algorithms allowed to sign
+	// ID tokens. If not provided, this defaults to the algorithms advertised by
+	// the JWK endpoint, then the set of algorithms supported by this package.
+	Algorithms []string
+}
+
+// NewProvider initializes a provider from a set of endpoints, rather than
+// through discovery.
+func (p *ProviderConfig) NewProvider(ctx context.Context) *Provider {
+	return &Provider{
+		issuer:       p.IssuerURL,
+		authURL:      p.AuthURL,
+		tokenURL:     p.TokenURL,
+		userInfoURL:  p.UserInfoURL,
+		algorithms:   p.Algorithms,
+		remoteKeySet: NewRemoteKeySet(cloneContext(ctx), p.JWKSURL),
+	}
+}
+
+// NewProvider uses the OpenID Connect discovery mechanism to construct a Provider.
+//
+// The issuer is the URL identifier for the service. For example: "https://accounts.google.com"
+// or "https://login.salesforce.com".
+func NewProvider(ctx context.Context, issuer string) (*Provider, error) {
+	wellKnown := strings.TrimSuffix(issuer, "/") + "/.well-known/openid-configuration"
+	req, err := http.NewRequest("GET", wellKnown, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := doRequest(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("unable to read response body: %v", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("%s: %s", resp.Status, body)
+	}
+
+	var p providerJSON
+	err = unmarshalResp(resp, body, &p)
+	if err != nil {
+		return nil, fmt.Errorf("oidc: failed to decode provider discovery object: %v", err)
+	}
+
+	issuerURL, skipIssuerValidation := ctx.Value(issuerURLKey).(string)
+	if !skipIssuerValidation {
+		issuerURL = issuer
+	}
+	if p.Issuer != issuerURL && !skipIssuerValidation {
+		return nil, fmt.Errorf("oidc: issuer did not match the issuer returned by provider, expected %q got %q", issuer, p.Issuer)
+	}
+	var algs []string
+	for _, a := range p.Algorithms {
+		if supportedAlgorithms[a] {
+			algs = append(algs, a)
+		}
+	}
+	return &Provider{
+		issuer:       issuerURL,
+		authURL:      p.AuthURL,
+		tokenURL:     p.TokenURL,
+		userInfoURL:  p.UserInfoURL,
+		algorithms:   algs,
+		rawClaims:    body,
+		remoteKeySet: NewRemoteKeySet(cloneContext(ctx), p.JWKSURL),
+	}, nil
+}
+
+// Claims unmarshals raw fields returned by the server during discovery.
+//
+//    var claims struct {
+//        ScopesSupported []string `json:"scopes_supported"`
+//        ClaimsSupported []string `json:"claims_supported"`
+//    }
+//
+//    if err := provider.Claims(&claims); err != nil {
+//        // handle unmarshaling error
+//    }
+//
+// For a list of fields defined by the OpenID Connect spec see:
+// https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderMetadata
+func (p *Provider) Claims(v interface{}) error {
+	if p.rawClaims == nil {
+		return errors.New("oidc: claims not set")
+	}
+	return json.Unmarshal(p.rawClaims, v)
+}
+
+// Endpoint returns the OAuth2 auth and token endpoints for the given provider.
+func (p *Provider) Endpoint() oauth2.Endpoint {
+	return oauth2.Endpoint{AuthURL: p.authURL, TokenURL: p.tokenURL}
+}
+
+// UserInfo represents the OpenID Connect userinfo claims.
+type UserInfo struct {
+	Subject       string `json:"sub"`
+	Profile       string `json:"profile"`
+	Email         string `json:"email"`
+	EmailVerified bool   `json:"email_verified"`
+
+	claims []byte
+}
+
+type userInfoRaw struct {
+	Subject string `json:"sub"`
+	Profile string `json:"profile"`
+	Email   string `json:"email"`
+	// Handle providers that return email_verified as a string
+	// https://forums.aws.amazon.com/thread.jspa?messageID=949441&#949441 and
+	// https://discuss.elastic.co/t/openid-error-after-authenticating-against-aws-cognito/206018/11
+	EmailVerified stringAsBool `json:"email_verified"`
+}
+
+// Claims unmarshals the raw JSON object claims into the provided object.
+func (u *UserInfo) Claims(v interface{}) error {
+	if u.claims == nil {
+		return errors.New("oidc: claims not set")
+	}
+	return json.Unmarshal(u.claims, v)
+}
+
+// UserInfo uses the token source to query the provider's user info endpoint.
+func (p *Provider) UserInfo(ctx context.Context, tokenSource oauth2.TokenSource) (*UserInfo, error) {
+	if p.userInfoURL == "" {
+		return nil, errors.New("oidc: user info endpoint is not supported by this provider")
+	}
+
+	req, err := http.NewRequest("GET", p.userInfoURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("oidc: create GET request: %v", err)
+	}
+
+	token, err := tokenSource.Token()
+	if err != nil {
+		return nil, fmt.Errorf("oidc: get access token: %v", err)
+	}
+	token.SetAuthHeader(req)
+
+	resp, err := doRequest(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("%s: %s", resp.Status, body)
+	}
+
+	ct := resp.Header.Get("Content-Type")
+	mediaType, _, parseErr := mime.ParseMediaType(ct)
+	if parseErr == nil && mediaType == "application/jwt" {
+		payload, err := p.remoteKeySet.VerifySignature(ctx, string(body))
+		if err != nil {
+			return nil, fmt.Errorf("oidc: invalid userinfo jwt signature %v", err)
+		}
+		body = payload
+	}
+
+	var userInfo userInfoRaw
+	if err := json.Unmarshal(body, &userInfo); err != nil {
+		return nil, fmt.Errorf("oidc: failed to decode userinfo: %v", err)
+	}
+	return &UserInfo{
+		Subject:       userInfo.Subject,
+		Profile:       userInfo.Profile,
+		Email:         userInfo.Email,
+		EmailVerified: bool(userInfo.EmailVerified),
+		claims:        body,
+	}, nil
+}
+
+// IDToken is an OpenID Connect extension that provides a predictable representation
+// of an authorization event.
+//
+// The ID Token only holds fields OpenID Connect requires. To access additional
+// claims returned by the server, use the Claims method.
+type IDToken struct {
+	// The URL of the server which issued this token. OpenID Connect
+	// requires this value always be identical to the URL used for
+	// initial discovery.
+	//
+	// Note: Because of a known issue with Google Accounts' implementation
+	// this value may differ when using Google.
+	//
+	// See: https://developers.google.com/identity/protocols/OpenIDConnect#obtainuserinfo
+	Issuer string
+
+	// The client ID, or set of client IDs, that this token is issued for. For
+	// common uses, this is the client that initialized the auth flow.
+	//
+	// This package ensures the audience contains an expected value.
+	Audience []string
+
+	// A unique string which identifies the end user.
+	Subject string
+
+	// Expiry of the token. Ths package will not process tokens that have
+	// expired unless that validation is explicitly turned off.
+	Expiry time.Time
+	// When the token was issued by the provider.
+	IssuedAt time.Time
+
+	// Initial nonce provided during the authentication redirect.
+	//
+	// This package does NOT provided verification on the value of this field
+	// and it's the user's responsibility to ensure it contains a valid value.
+	Nonce string
+
+	// at_hash claim, if set in the ID token. Callers can verify an access token
+	// that corresponds to the ID token using the VerifyAccessToken method.
+	AccessTokenHash string
+
+	// signature algorithm used for ID token, needed to compute a verification hash of an
+	// access token
+	sigAlgorithm string
+
+	// Raw payload of the id_token.
+	claims []byte
+
+	// Map of distributed claim names to claim sources
+	distributedClaims map[string]claimSource
+}
+
+// Claims unmarshals the raw JSON payload of the ID Token into a provided struct.
+//
+//		idToken, err := idTokenVerifier.Verify(rawIDToken)
+//		if err != nil {
+//			// handle error
+//		}
+//		var claims struct {
+//			Email         string `json:"email"`
+//			EmailVerified bool   `json:"email_verified"`
+//		}
+//		if err := idToken.Claims(&claims); err != nil {
+//			// handle error
+//		}
+//
+func (i *IDToken) Claims(v interface{}) error {
+	if i.claims == nil {
+		return errors.New("oidc: claims not set")
+	}
+	return json.Unmarshal(i.claims, v)
+}
+
+// VerifyAccessToken verifies that the hash of the access token that corresponds to the iD token
+// matches the hash in the id token. It returns an error if the hashes  don't match.
+// It is the caller's responsibility to ensure that the optional access token hash is present for the ID token
+// before calling this method. See https://openid.net/specs/openid-connect-core-1_0.html#CodeIDToken
+func (i *IDToken) VerifyAccessToken(accessToken string) error {
+	if i.AccessTokenHash == "" {
+		return errNoAtHash
+	}
+	var h hash.Hash
+	switch i.sigAlgorithm {
+	case RS256, ES256, PS256:
+		h = sha256.New()
+	case RS384, ES384, PS384:
+		h = sha512.New384()
+	case RS512, ES512, PS512:
+		h = sha512.New()
+	default:
+		return fmt.Errorf("oidc: unsupported signing algorithm %q", i.sigAlgorithm)
+	}
+	h.Write([]byte(accessToken)) // hash documents that Write will never return an error
+	sum := h.Sum(nil)[:h.Size()/2]
+	actual := base64.RawURLEncoding.EncodeToString(sum)
+	if actual != i.AccessTokenHash {
+		return errInvalidAtHash
+	}
+	return nil
+}
+
+type idToken struct {
+	Issuer       string                 `json:"iss"`
+	Subject      string                 `json:"sub"`
+	Audience     audience               `json:"aud"`
+	Expiry       jsonTime               `json:"exp"`
+	IssuedAt     jsonTime               `json:"iat"`
+	NotBefore    *jsonTime              `json:"nbf"`
+	Nonce        string                 `json:"nonce"`
+	AtHash       string                 `json:"at_hash"`
+	ClaimNames   map[string]string      `json:"_claim_names"`
+	ClaimSources map[string]claimSource `json:"_claim_sources"`
+}
+
+type claimSource struct {
+	Endpoint    string `json:"endpoint"`
+	AccessToken string `json:"access_token"`
+}
+
+type stringAsBool bool
+
+func (sb *stringAsBool) UnmarshalJSON(b []byte) error {
+	switch string(b) {
+	case "true", `"true"`:
+		*sb = true
+	case "false", `"false"`:
+		*sb = false
+	default:
+		return errors.New("invalid value for boolean")
+	}
+	return nil
+}
+
+type audience []string
+
+func (a *audience) UnmarshalJSON(b []byte) error {
+	var s string
+	if json.Unmarshal(b, &s) == nil {
+		*a = audience{s}
+		return nil
+	}
+	var auds []string
+	if err := json.Unmarshal(b, &auds); err != nil {
+		return err
+	}
+	*a = auds
+	return nil
+}
+
+type jsonTime time.Time
+
+func (j *jsonTime) UnmarshalJSON(b []byte) error {
+	var n json.Number
+	if err := json.Unmarshal(b, &n); err != nil {
+		return err
+	}
+	var unix int64
+
+	if t, err := n.Int64(); err == nil {
+		unix = t
+	} else {
+		f, err := n.Float64()
+		if err != nil {
+			return err
+		}
+		unix = int64(f)
+	}
+	*j = jsonTime(time.Unix(unix, 0))
+	return nil
+}
+
+func unmarshalResp(r *http.Response, body []byte, v interface{}) error {
+	err := json.Unmarshal(body, &v)
+	if err == nil {
+		return nil
+	}
+	ct := r.Header.Get("Content-Type")
+	mediaType, _, parseErr := mime.ParseMediaType(ct)
+	if parseErr == nil && mediaType == "application/json" {
+		return fmt.Errorf("got Content-Type = application/json, but could not unmarshal as JSON: %v", err)
+	}
+	return fmt.Errorf("expected Content-Type = application/json, got %q: %v", ct, err)
+}
@@ -0,0 +1,344 @@
+package oidc
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+	"time"
+
+	"golang.org/x/oauth2"
+	jose "gopkg.in/square/go-jose.v2"
+)
+
+const (
+	issuerGoogleAccounts         = "https://accounts.google.com"
+	issuerGoogleAccountsNoScheme = "accounts.google.com"
+)
+
+// TokenExpiredError indicates that Verify failed because the token was expired. This
+// error does NOT indicate that the token is not also invalid for other reasons. Other
+// checks might have failed if the expiration check had not failed.
+type TokenExpiredError struct {
+	// Expiry is the time when the token expired.
+	Expiry time.Time
+}
+
+func (e *TokenExpiredError) Error() string {
+	return fmt.Sprintf("oidc: token is expired (Token Expiry: %v)", e.Expiry)
+}
+
+// KeySet is a set of publc JSON Web Keys that can be used to validate the signature
+// of JSON web tokens. This is expected to be backed by a remote key set through
+// provider metadata discovery or an in-memory set of keys delivered out-of-band.
+type KeySet interface {
+	// VerifySignature parses the JSON web token, verifies the signature, and returns
+	// the raw payload. Header and claim fields are validated by other parts of the
+	// package. For example, the KeySet does not need to check values such as signature
+	// algorithm, issuer, and audience since the IDTokenVerifier validates these values
+	// independently.
+	//
+	// If VerifySignature makes HTTP requests to verify the token, it's expected to
+	// use any HTTP client associated with the context through ClientContext.
+	VerifySignature(ctx context.Context, jwt string) (payload []byte, err error)
+}
+
+// IDTokenVerifier provides verification for ID Tokens.
+type IDTokenVerifier struct {
+	keySet KeySet
+	config *Config
+	issuer string
+}
+
+// NewVerifier returns a verifier manually constructed from a key set and issuer URL.
+//
+// It's easier to use provider discovery to construct an IDTokenVerifier than creating
+// one directly. This method is intended to be used with provider that don't support
+// metadata discovery, or avoiding round trips when the key set URL is already known.
+//
+// This constructor can be used to create a verifier directly using the issuer URL and
+// JSON Web Key Set URL without using discovery:
+//
+//		keySet := oidc.NewRemoteKeySet(ctx, "https://www.googleapis.com/oauth2/v3/certs")
+//		verifier := oidc.NewVerifier("https://accounts.google.com", keySet, config)
+//
+// Or a static key set (e.g. for testing):
+//
+//		keySet := &oidc.StaticKeySet{PublicKeys: []crypto.PublicKey{pub1, pub2}}
+//		verifier := oidc.NewVerifier("https://accounts.google.com", keySet, config)
+//
+func NewVerifier(issuerURL string, keySet KeySet, config *Config) *IDTokenVerifier {
+	return &IDTokenVerifier{keySet: keySet, config: config, issuer: issuerURL}
+}
+
+// Config is the configuration for an IDTokenVerifier.
+type Config struct {
+	// Expected audience of the token. For a majority of the cases this is expected to be
+	// the ID of the client that initialized the login flow. It may occasionally differ if
+	// the provider supports the authorizing party (azp) claim.
+	//
+	// If not provided, users must explicitly set SkipClientIDCheck.
+	ClientID string
+	// If specified, only this set of algorithms may be used to sign the JWT.
+	//
+	// If the IDTokenVerifier is created from a provider with (*Provider).Verifier, this
+	// defaults to the set of algorithms the provider supports. Otherwise this values
+	// defaults to RS256.
+	SupportedSigningAlgs []string
+
+	// If true, no ClientID check performed. Must be true if ClientID field is empty.
+	SkipClientIDCheck bool
+	// If true, token expiry is not checked.
+	SkipExpiryCheck bool
+
+	// SkipIssuerCheck is intended for specialized cases where the the caller wishes to
+	// defer issuer validation. When enabled, callers MUST independently verify the Token's
+	// Issuer is a known good value.
+	//
+	// Mismatched issuers often indicate client mis-configuration. If mismatches are
+	// unexpected, evaluate if the provided issuer URL is incorrect instead of enabling
+	// this option.
+	SkipIssuerCheck bool
+
+	// Time function to check Token expiry. Defaults to time.Now
+	Now func() time.Time
+
+	// InsecureSkipSignatureCheck causes this package to skip JWT signature validation.
+	// It's intended for special cases where providers (such as Azure), use the "none"
+	// algorithm.
+	//
+	// This option can only be enabled safely when the ID Token is received directly
+	// from the provider after the token exchange.
+	//
+	// This option MUST NOT be used when receiving an ID Token from sources other
+	// than the token endpoint.
+	InsecureSkipSignatureCheck bool
+}
+
+// Verifier returns an IDTokenVerifier that uses the provider's key set to verify JWTs.
+func (p *Provider) Verifier(config *Config) *IDTokenVerifier {
+	if len(config.SupportedSigningAlgs) == 0 && len(p.algorithms) > 0 {
+		// Make a copy so we don't modify the config values.
+		cp := &Config{}
+		*cp = *config
+		cp.SupportedSigningAlgs = p.algorithms
+		config = cp
+	}
+	return NewVerifier(p.issuer, p.remoteKeySet, config)
+}
+
+func parseJWT(p string) ([]byte, error) {
+	parts := strings.Split(p, ".")
+	if len(parts) < 2 {
+		return nil, fmt.Errorf("oidc: malformed jwt, expected 3 parts got %d", len(parts))
+	}
+	payload, err := base64.RawURLEncoding.DecodeString(parts[1])
+	if err != nil {
+		return nil, fmt.Errorf("oidc: malformed jwt payload: %v", err)
+	}
+	return payload, nil
+}
+
+func contains(sli []string, ele string) bool {
+	for _, s := range sli {
+		if s == ele {
+			return true
+		}
+	}
+	return false
+}
+
+// Returns the Claims from the distributed JWT token
+func resolveDistributedClaim(ctx context.Context, verifier *IDTokenVerifier, src claimSource) ([]byte, error) {
+	req, err := http.NewRequest("GET", src.Endpoint, nil)
+	if err != nil {
+		return nil, fmt.Errorf("malformed request: %v", err)
+	}
+	if src.AccessToken != "" {
+		req.Header.Set("Authorization", "Bearer "+src.AccessToken)
+	}
+
+	resp, err := doRequest(ctx, req)
+	if err != nil {
+		return nil, fmt.Errorf("oidc: Request to endpoint failed: %v", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("unable to read response body: %v", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("oidc: request failed: %v", resp.StatusCode)
+	}
+
+	token, err := verifier.Verify(ctx, string(body))
+	if err != nil {
+		return nil, fmt.Errorf("malformed response body: %v", err)
+	}
+
+	return token.claims, nil
+}
+
+// Verify parses a raw ID Token, verifies it's been signed by the provider, performs
+// any additional checks depending on the Config, and returns the payload.
+//
+// Verify does NOT do nonce validation, which is the callers responsibility.
+//
+// See: https://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation
+//
+//    oauth2Token, err := oauth2Config.Exchange(ctx, r.URL.Query().Get("code"))
+//    if err != nil {
+//        // handle error
+//    }
+//
+//    // Extract the ID Token from oauth2 token.
+//    rawIDToken, ok := oauth2Token.Extra("id_token").(string)
+//    if !ok {
+//        // handle error
+//    }
+//
+//    token, err := verifier.Verify(ctx, rawIDToken)
+//
+func (v *IDTokenVerifier) Verify(ctx context.Context, rawIDToken string) (*IDToken, error) {
+	// Throw out tokens with invalid claims before trying to verify the token. This lets
+	// us do cheap checks before possibly re-syncing keys.
+	payload, err := parseJWT(rawIDToken)
+	if err != nil {
+		return nil, fmt.Errorf("oidc: malformed jwt: %v", err)
+	}
+	var token idToken
+	if err := json.Unmarshal(payload, &token); err != nil {
+		return nil, fmt.Errorf("oidc: failed to unmarshal claims: %v", err)
+	}
+
+	distributedClaims := make(map[string]claimSource)
+
+	//step through the token to map claim names to claim sources"
+	for cn, src := range token.ClaimNames {
+		if src == "" {
+			return nil, fmt.Errorf("oidc: failed to obtain source from claim name")
+		}
+		s, ok := token.ClaimSources[src]
+		if !ok {
+			return nil, fmt.Errorf("oidc: source does not exist")
+		}
+		distributedClaims[cn] = s
+	}
+
+	t := &IDToken{
+		Issuer:            token.Issuer,
+		Subject:           token.Subject,
+		Audience:          []string(token.Audience),
+		Expiry:            time.Time(token.Expiry),
+		IssuedAt:          time.Time(token.IssuedAt),
+		Nonce:             token.Nonce,
+		AccessTokenHash:   token.AtHash,
+		claims:            payload,
+		distributedClaims: distributedClaims,
+	}
+
+	// Check issuer.
+	if !v.config.SkipIssuerCheck && t.Issuer != v.issuer {
+		// Google sometimes returns "accounts.google.com" as the issuer claim instead of
+		// the required "https://accounts.google.com". Detect this case and allow it only
+		// for Google.
+		//
+		// We will not add hooks to let other providers go off spec like this.
+		if !(v.issuer == issuerGoogleAccounts && t.Issuer == issuerGoogleAccountsNoScheme) {
+			return nil, fmt.Errorf("oidc: id token issued by a different provider, expected %q got %q", v.issuer, t.Issuer)
+		}
+	}
+
+	// If a client ID has been provided, make sure it's part of the audience. SkipClientIDCheck must be true if ClientID is empty.
+	//
+	// This check DOES NOT ensure that the ClientID is the party to which the ID Token was issued (i.e. Authorized party).
+	if !v.config.SkipClientIDCheck {
+		if v.config.ClientID != "" {
+			if !contains(t.Audience, v.config.ClientID) {
+				return nil, fmt.Errorf("oidc: expected audience %q got %q", v.config.ClientID, t.Audience)
+			}
+		} else {
+			return nil, fmt.Errorf("oidc: invalid configuration, clientID must be provided or SkipClientIDCheck must be set")
+		}
+	}
+
+	// If a SkipExpiryCheck is false, make sure token is not expired.
+	if !v.config.SkipExpiryCheck {
+		now := time.Now
+		if v.config.Now != nil {
+			now = v.config.Now
+		}
+		nowTime := now()
+
+		if t.Expiry.Before(nowTime) {
+			return nil, &TokenExpiredError{Expiry: t.Expiry}
+		}
+
+		// If nbf claim is provided in token, ensure that it is indeed in the past.
+		if token.NotBefore != nil {
+			nbfTime := time.Time(*token.NotBefore)
+			// Set to 5 minutes since this is what other OpenID Connect providers do to deal with clock skew.
+			// https://github.com/AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet/blob/6.12.2/src/Microsoft.IdentityModel.Tokens/TokenValidationParameters.cs#L149-L153
+			leeway := 5 * time.Minute
+
+			if nowTime.Add(leeway).Before(nbfTime) {
+				return nil, fmt.Errorf("oidc: current time %v before the nbf (not before) time: %v", nowTime, nbfTime)
+			}
+		}
+	}
+
+	if v.config.InsecureSkipSignatureCheck {
+		return t, nil
+	}
+
+	jws, err := jose.ParseSigned(rawIDToken)
+	if err != nil {
+		return nil, fmt.Errorf("oidc: malformed jwt: %v", err)
+	}
+
+	switch len(jws.Signatures) {
+	case 0:
+		return nil, fmt.Errorf("oidc: id token not signed")
+	case 1:
+	default:
+		return nil, fmt.Errorf("oidc: multiple signatures on id token not supported")
+	}
+
+	sig := jws.Signatures[0]
+	supportedSigAlgs := v.config.SupportedSigningAlgs
+	if len(supportedSigAlgs) == 0 {
+		supportedSigAlgs = []string{RS256}
+	}
+
+	if !contains(supportedSigAlgs, sig.Header.Algorithm) {
+		return nil, fmt.Errorf("oidc: id token signed with unsupported algorithm, expected %q got %q", supportedSigAlgs, sig.Header.Algorithm)
+	}
+
+	t.sigAlgorithm = sig.Header.Algorithm
+
+	ctx = context.WithValue(ctx, parsedJWTKey, jws)
+	gotPayload, err := v.keySet.VerifySignature(ctx, rawIDToken)
+	if err != nil {
+		return nil, fmt.Errorf("failed to verify signature: %v", err)
+	}
+
+	// Ensure that the payload returned by the square actually matches the payload parsed earlier.
+	if !bytes.Equal(gotPayload, payload) {
+		return nil, errors.New("oidc: internal error, payload parsed did not match previous payload")
+	}
+
+	return t, nil
+}
+
+// Nonce returns an auth code option which requires the ID Token created by the
+// OpenID Connect provider to contain the specified nonce.
+func Nonce(nonce string) oauth2.AuthCodeOption {
+	return oauth2.SetAuthURLParam("nonce", nonce)
+}
@@ -0,0 +1,524 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package jsonpb
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/encoding/protojson"
+	protoV2 "google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+)
+
+const wrapJSONUnmarshalV2 = false
+
+// UnmarshalNext unmarshals the next JSON object from d into m.
+func UnmarshalNext(d *json.Decoder, m proto.Message) error {
+	return new(Unmarshaler).UnmarshalNext(d, m)
+}
+
+// Unmarshal unmarshals a JSON object from r into m.
+func Unmarshal(r io.Reader, m proto.Message) error {
+	return new(Unmarshaler).Unmarshal(r, m)
+}
+
+// UnmarshalString unmarshals a JSON object from s into m.
+func UnmarshalString(s string, m proto.Message) error {
+	return new(Unmarshaler).Unmarshal(strings.NewReader(s), m)
+}
+
+// Unmarshaler is a configurable object for converting from a JSON
+// representation to a protocol buffer object.
+type Unmarshaler struct {
+	// AllowUnknownFields specifies whether to allow messages to contain
+	// unknown JSON fields, as opposed to failing to unmarshal.
+	AllowUnknownFields bool
+
+	// AnyResolver is used to resolve the google.protobuf.Any well-known type.
+	// If unset, the global registry is used by default.
+	AnyResolver AnyResolver
+}
+
+// JSONPBUnmarshaler is implemented by protobuf messages that customize the way
+// they are unmarshaled from JSON. Messages that implement this should also
+// implement JSONPBMarshaler so that the custom format can be produced.
+//
+// The JSON unmarshaling must follow the JSON to proto specification:
+//	https://developers.google.com/protocol-buffers/docs/proto3#json
+//
+// Deprecated: Custom types should implement protobuf reflection instead.
+type JSONPBUnmarshaler interface {
+	UnmarshalJSONPB(*Unmarshaler, []byte) error
+}
+
+// Unmarshal unmarshals a JSON object from r into m.
+func (u *Unmarshaler) Unmarshal(r io.Reader, m proto.Message) error {
+	return u.UnmarshalNext(json.NewDecoder(r), m)
+}
+
+// UnmarshalNext unmarshals the next JSON object from d into m.
+func (u *Unmarshaler) UnmarshalNext(d *json.Decoder, m proto.Message) error {
+	if m == nil {
+		return errors.New("invalid nil message")
+	}
+
+	// Parse the next JSON object from the stream.
+	raw := json.RawMessage{}
+	if err := d.Decode(&raw); err != nil {
+		return err
+	}
+
+	// Check for custom unmarshalers first since they may not properly
+	// implement protobuf reflection that the logic below relies on.
+	if jsu, ok := m.(JSONPBUnmarshaler); ok {
+		return jsu.UnmarshalJSONPB(u, raw)
+	}
+
+	mr := proto.MessageReflect(m)
+
+	// NOTE: For historical reasons, a top-level null is treated as a noop.
+	// This is incorrect, but kept for compatibility.
+	if string(raw) == "null" && mr.Descriptor().FullName() != "google.protobuf.Value" {
+		return nil
+	}
+
+	if wrapJSONUnmarshalV2 {
+		// NOTE: If input message is non-empty, we need to preserve merge semantics
+		// of the old jsonpb implementation. These semantics are not supported by
+		// the protobuf JSON specification.
+		isEmpty := true
+		mr.Range(func(protoreflect.FieldDescriptor, protoreflect.Value) bool {
+			isEmpty = false // at least one iteration implies non-empty
+			return false
+		})
+		if !isEmpty {
+			// Perform unmarshaling into a newly allocated, empty message.
+			mr = mr.New()
+
+			// Use a defer to copy all unmarshaled fields into the original message.
+			dst := proto.MessageReflect(m)
+			defer mr.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
+				dst.Set(fd, v)
+				return true
+			})
+		}
+
+		// Unmarshal using the v2 JSON unmarshaler.
+		opts := protojson.UnmarshalOptions{
+			DiscardUnknown: u.AllowUnknownFields,
+		}
+		if u.AnyResolver != nil {
+			opts.Resolver = anyResolver{u.AnyResolver}
+		}
+		return opts.Unmarshal(raw, mr.Interface())
+	} else {
+		if err := u.unmarshalMessage(mr, raw); err != nil {
+			return err
+		}
+		return protoV2.CheckInitialized(mr.Interface())
+	}
+}
+
+func (u *Unmarshaler) unmarshalMessage(m protoreflect.Message, in []byte) error {
+	md := m.Descriptor()
+	fds := md.Fields()
+
+	if jsu, ok := proto.MessageV1(m.Interface()).(JSONPBUnmarshaler); ok {
+		return jsu.UnmarshalJSONPB(u, in)
+	}
+
+	if string(in) == "null" && md.FullName() != "google.protobuf.Value" {
+		return nil
+	}
+
+	switch wellKnownType(md.FullName()) {
+	case "Any":
+		var jsonObject map[string]json.RawMessage
+		if err := json.Unmarshal(in, &jsonObject); err != nil {
+			return err
+		}
+
+		rawTypeURL, ok := jsonObject["@type"]
+		if !ok {
+			return errors.New("Any JSON doesn't have '@type'")
+		}
+		typeURL, err := unquoteString(string(rawTypeURL))
+		if err != nil {
+			return fmt.Errorf("can't unmarshal Any's '@type': %q", rawTypeURL)
+		}
+		m.Set(fds.ByNumber(1), protoreflect.ValueOfString(typeURL))
+
+		var m2 protoreflect.Message
+		if u.AnyResolver != nil {
+			mi, err := u.AnyResolver.Resolve(typeURL)
+			if err != nil {
+				return err
+			}
+			m2 = proto.MessageReflect(mi)
+		} else {
+			mt, err := protoregistry.GlobalTypes.FindMessageByURL(typeURL)
+			if err != nil {
+				if err == protoregistry.NotFound {
+					return fmt.Errorf("could not resolve Any message type: %v", typeURL)
+				}
+				return err
+			}
+			m2 = mt.New()
+		}
+
+		if wellKnownType(m2.Descriptor().FullName()) != "" {
+			rawValue, ok := jsonObject["value"]
+			if !ok {
+				return errors.New("Any JSON doesn't have 'value'")
+			}
+			if err := u.unmarshalMessage(m2, rawValue); err != nil {
+				return fmt.Errorf("can't unmarshal Any nested proto %v: %v", typeURL, err)
+			}
+		} else {
+			delete(jsonObject, "@type")
+			rawJSON, err := json.Marshal(jsonObject)
+			if err != nil {
+				return fmt.Errorf("can't generate JSON for Any's nested proto to be unmarshaled: %v", err)
+			}
+			if err = u.unmarshalMessage(m2, rawJSON); err != nil {
+				return fmt.Errorf("can't unmarshal Any nested proto %v: %v", typeURL, err)
+			}
+		}
+
+		rawWire, err := protoV2.Marshal(m2.Interface())
+		if err != nil {
+			return fmt.Errorf("can't marshal proto %v into Any.Value: %v", typeURL, err)
+		}
+		m.Set(fds.ByNumber(2), protoreflect.ValueOfBytes(rawWire))
+		return nil
+	case "BoolValue", "BytesValue", "StringValue",
+		"Int32Value", "UInt32Value", "FloatValue",
+		"Int64Value", "UInt64Value", "DoubleValue":
+		fd := fds.ByNumber(1)
+		v, err := u.unmarshalValue(m.NewField(fd), in, fd)
+		if err != nil {
+			return err
+		}
+		m.Set(fd, v)
+		return nil
+	case "Duration":
+		v, err := unquoteString(string(in))
+		if err != nil {
+			return err
+		}
+		d, err := time.ParseDuration(v)
+		if err != nil {
+			return fmt.Errorf("bad Duration: %v", err)
+		}
+
+		sec := d.Nanoseconds() / 1e9
+		nsec := d.Nanoseconds() % 1e9
+		m.Set(fds.ByNumber(1), protoreflect.ValueOfInt64(int64(sec)))
+		m.Set(fds.ByNumber(2), protoreflect.ValueOfInt32(int32(nsec)))
+		return nil
+	case "Timestamp":
+		v, err := unquoteString(string(in))
+		if err != nil {
+			return err
+		}
+		t, err := time.Parse(time.RFC3339Nano, v)
+		if err != nil {
+			return fmt.Errorf("bad Timestamp: %v", err)
+		}
+
+		sec := t.Unix()
+		nsec := t.Nanosecond()
+		m.Set(fds.ByNumber(1), protoreflect.ValueOfInt64(int64(sec)))
+		m.Set(fds.ByNumber(2), protoreflect.ValueOfInt32(int32(nsec)))
+		return nil
+	case "Value":
+		switch {
+		case string(in) == "null":
+			m.Set(fds.ByNumber(1), protoreflect.ValueOfEnum(0))
+		case string(in) == "true":
+			m.Set(fds.ByNumber(4), protoreflect.ValueOfBool(true))
+		case string(in) == "false":
+			m.Set(fds.ByNumber(4), protoreflect.ValueOfBool(false))
+		case hasPrefixAndSuffix('"', in, '"'):
+			s, err := unquoteString(string(in))
+			if err != nil {
+				return fmt.Errorf("unrecognized type for Value %q", in)
+			}
+			m.Set(fds.ByNumber(3), protoreflect.ValueOfString(s))
+		case hasPrefixAndSuffix('[', in, ']'):
+			v := m.Mutable(fds.ByNumber(6))
+			return u.unmarshalMessage(v.Message(), in)
+		case hasPrefixAndSuffix('{', in, '}'):
+			v := m.Mutable(fds.ByNumber(5))
+			return u.unmarshalMessage(v.Message(), in)
+		default:
+			f, err := strconv.ParseFloat(string(in), 0)
+			if err != nil {
+				return fmt.Errorf("unrecognized type for Value %q", in)
+			}
+			m.Set(fds.ByNumber(2), protoreflect.ValueOfFloat64(f))
+		}
+		return nil
+	case "ListValue":
+		var jsonArray []json.RawMessage
+		if err := json.Unmarshal(in, &jsonArray); err != nil {
+			return fmt.Errorf("bad ListValue: %v", err)
+		}
+
+		lv := m.Mutable(fds.ByNumber(1)).List()
+		for _, raw := range jsonArray {
+			ve := lv.NewElement()
+			if err := u.unmarshalMessage(ve.Message(), raw); err != nil {
+				return err
+			}
+			lv.Append(ve)
+		}
+		return nil
+	case "Struct":
+		var jsonObject map[string]json.RawMessage
+		if err := json.Unmarshal(in, &jsonObject); err != nil {
+			return fmt.Errorf("bad StructValue: %v", err)
+		}
+
+		mv := m.Mutable(fds.ByNumber(1)).Map()
+		for key, raw := range jsonObject {
+			kv := protoreflect.ValueOf(key).MapKey()
+			vv := mv.NewValue()
+			if err := u.unmarshalMessage(vv.Message(), raw); err != nil {
+				return fmt.Errorf("bad value in StructValue for key %q: %v", key, err)
+			}
+			mv.Set(kv, vv)
+		}
+		return nil
+	}
+
+	var jsonObject map[string]json.RawMessage
+	if err := json.Unmarshal(in, &jsonObject); err != nil {
+		return err
+	}
+
+	// Handle known fields.
+	for i := 0; i < fds.Len(); i++ {
+		fd := fds.Get(i)
+		if fd.IsWeak() && fd.Message().IsPlaceholder() {
+			continue //  weak reference is not linked in
+		}
+
+		// Search for any raw JSON value associated with this field.
+		var raw json.RawMessage
+		name := string(fd.Name())
+		if fd.Kind() == protoreflect.GroupKind {
+			name = string(fd.Message().Name())
+		}
+		if v, ok := jsonObject[name]; ok {
+			delete(jsonObject, name)
+			raw = v
+		}
+		name = string(fd.JSONName())
+		if v, ok := jsonObject[name]; ok {
+			delete(jsonObject, name)
+			raw = v
+		}
+
+		field := m.NewField(fd)
+		// Unmarshal the field value.
+		if raw == nil || (string(raw) == "null" && !isSingularWellKnownValue(fd) && !isSingularJSONPBUnmarshaler(field, fd)) {
+			continue
+		}
+		v, err := u.unmarshalValue(field, raw, fd)
+		if err != nil {
+			return err
+		}
+		m.Set(fd, v)
+	}
+
+	// Handle extension fields.
+	for name, raw := range jsonObject {
+		if !strings.HasPrefix(name, "[") || !strings.HasSuffix(name, "]") {
+			continue
+		}
+
+		// Resolve the extension field by name.
+		xname := protoreflect.FullName(name[len("[") : len(name)-len("]")])
+		xt, _ := protoregistry.GlobalTypes.FindExtensionByName(xname)
+		if xt == nil && isMessageSet(md) {
+			xt, _ = protoregistry.GlobalTypes.FindExtensionByName(xname.Append("message_set_extension"))
+		}
+		if xt == nil {
+			continue
+		}
+		delete(jsonObject, name)
+		fd := xt.TypeDescriptor()
+		if fd.ContainingMessage().FullName() != m.Descriptor().FullName() {
+			return fmt.Errorf("extension field %q does not extend message %q", xname, m.Descriptor().FullName())
+		}
+
+		field := m.NewField(fd)
+		// Unmarshal the field value.
+		if raw == nil || (string(raw) == "null" && !isSingularWellKnownValue(fd) && !isSingularJSONPBUnmarshaler(field, fd)) {
+			continue
+		}
+		v, err := u.unmarshalValue(field, raw, fd)
+		if err != nil {
+			return err
+		}
+		m.Set(fd, v)
+	}
+
+	if !u.AllowUnknownFields && len(jsonObject) > 0 {
+		for name := range jsonObject {
+			return fmt.Errorf("unknown field %q in %v", name, md.FullName())
+		}
+	}
+	return nil
+}
+
+func isSingularWellKnownValue(fd protoreflect.FieldDescriptor) bool {
+	if md := fd.Message(); md != nil {
+		return md.FullName() == "google.protobuf.Value" && fd.Cardinality() != protoreflect.Repeated
+	}
+	return false
+}
+
+func isSingularJSONPBUnmarshaler(v protoreflect.Value, fd protoreflect.FieldDescriptor) bool {
+	if fd.Message() != nil && fd.Cardinality() != protoreflect.Repeated {
+		_, ok := proto.MessageV1(v.Interface()).(JSONPBUnmarshaler)
+		return ok
+	}
+	return false
+}
+
+func (u *Unmarshaler) unmarshalValue(v protoreflect.Value, in []byte, fd protoreflect.FieldDescriptor) (protoreflect.Value, error) {
+	switch {
+	case fd.IsList():
+		var jsonArray []json.RawMessage
+		if err := json.Unmarshal(in, &jsonArray); err != nil {
+			return v, err
+		}
+		lv := v.List()
+		for _, raw := range jsonArray {
+			ve, err := u.unmarshalSingularValue(lv.NewElement(), raw, fd)
+			if err != nil {
+				return v, err
+			}
+			lv.Append(ve)
+		}
+		return v, nil
+	case fd.IsMap():
+		var jsonObject map[string]json.RawMessage
+		if err := json.Unmarshal(in, &jsonObject); err != nil {
+			return v, err
+		}
+		kfd := fd.MapKey()
+		vfd := fd.MapValue()
+		mv := v.Map()
+		for key, raw := range jsonObject {
+			var kv protoreflect.MapKey
+			if kfd.Kind() == protoreflect.StringKind {
+				kv = protoreflect.ValueOf(key).MapKey()
+			} else {
+				v, err := u.unmarshalSingularValue(kfd.Default(), []byte(key), kfd)
+				if err != nil {
+					return v, err
+				}
+				kv = v.MapKey()
+			}
+
+			vv, err := u.unmarshalSingularValue(mv.NewValue(), raw, vfd)
+			if err != nil {
+				return v, err
+			}
+			mv.Set(kv, vv)
+		}
+		return v, nil
+	default:
+		return u.unmarshalSingularValue(v, in, fd)
+	}
+}
+
+var nonFinite = map[string]float64{
+	`"NaN"`:       math.NaN(),
+	`"Infinity"`:  math.Inf(+1),
+	`"-Infinity"`: math.Inf(-1),
+}
+
+func (u *Unmarshaler) unmarshalSingularValue(v protoreflect.Value, in []byte, fd protoreflect.FieldDescriptor) (protoreflect.Value, error) {
+	switch fd.Kind() {
+	case protoreflect.BoolKind:
+		return unmarshalValue(in, new(bool))
+	case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind:
+		return unmarshalValue(trimQuote(in), new(int32))
+	case protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Sfixed64Kind:
+		return unmarshalValue(trimQuote(in), new(int64))
+	case protoreflect.Uint32Kind, protoreflect.Fixed32Kind:
+		return unmarshalValue(trimQuote(in), new(uint32))
+	case protoreflect.Uint64Kind, protoreflect.Fixed64Kind:
+		return unmarshalValue(trimQuote(in), new(uint64))
+	case protoreflect.FloatKind:
+		if f, ok := nonFinite[string(in)]; ok {
+			return protoreflect.ValueOfFloat32(float32(f)), nil
+		}
+		return unmarshalValue(trimQuote(in), new(float32))
+	case protoreflect.DoubleKind:
+		if f, ok := nonFinite[string(in)]; ok {
+			return protoreflect.ValueOfFloat64(float64(f)), nil
+		}
+		return unmarshalValue(trimQuote(in), new(float64))
+	case protoreflect.StringKind:
+		return unmarshalValue(in, new(string))
+	case protoreflect.BytesKind:
+		return unmarshalValue(in, new([]byte))
+	case protoreflect.EnumKind:
+		if hasPrefixAndSuffix('"', in, '"') {
+			vd := fd.Enum().Values().ByName(protoreflect.Name(trimQuote(in)))
+			if vd == nil {
+				return v, fmt.Errorf("unknown value %q for enum %s", in, fd.Enum().FullName())
+			}
+			return protoreflect.ValueOfEnum(vd.Number()), nil
+		}
+		return unmarshalValue(in, new(protoreflect.EnumNumber))
+	case protoreflect.MessageKind, protoreflect.GroupKind:
+		err := u.unmarshalMessage(v.Message(), in)
+		return v, err
+	default:
+		panic(fmt.Sprintf("invalid kind %v", fd.Kind()))
+	}
+}
+
+func unmarshalValue(in []byte, v interface{}) (protoreflect.Value, error) {
+	err := json.Unmarshal(in, v)
+	return protoreflect.ValueOf(reflect.ValueOf(v).Elem().Interface()), err
+}
+
+func unquoteString(in string) (out string, err error) {
+	err = json.Unmarshal([]byte(in), &out)
+	return out, err
+}
+
+func hasPrefixAndSuffix(prefix byte, in []byte, suffix byte) bool {
+	if len(in) >= 2 && in[0] == prefix && in[len(in)-1] == suffix {
+		return true
+	}
+	return false
+}
+
+// trimQuote is like unquoteString but simply strips surrounding quotes.
+// This is incorrect, but is behavior done by the legacy implementation.
+func trimQuote(in []byte) []byte {
+	if len(in) >= 2 && in[0] == '"' && in[len(in)-1] == '"' {
+		in = in[1 : len(in)-1]
+	}
+	return in
+}
@@ -0,0 +1,559 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package jsonpb
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/encoding/protojson"
+	protoV2 "google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+)
+
+const wrapJSONMarshalV2 = false
+
+// Marshaler is a configurable object for marshaling protocol buffer messages
+// to the specified JSON representation.
+type Marshaler struct {
+	// OrigName specifies whether to use the original protobuf name for fields.
+	OrigName bool
+
+	// EnumsAsInts specifies whether to render enum values as integers,
+	// as opposed to string values.
+	EnumsAsInts bool
+
+	// EmitDefaults specifies whether to render fields with zero values.
+	EmitDefaults bool
+
+	// Indent controls whether the output is compact or not.
+	// If empty, the output is compact JSON. Otherwise, every JSON object
+	// entry and JSON array value will be on its own line.
+	// Each line will be preceded by repeated copies of Indent, where the
+	// number of copies is the current indentation depth.
+	Indent string
+
+	// AnyResolver is used to resolve the google.protobuf.Any well-known type.
+	// If unset, the global registry is used by default.
+	AnyResolver AnyResolver
+}
+
+// JSONPBMarshaler is implemented by protobuf messages that customize the
+// way they are marshaled to JSON. Messages that implement this should also
+// implement JSONPBUnmarshaler so that the custom format can be parsed.
+//
+// The JSON marshaling must follow the proto to JSON specification:
+//	https://developers.google.com/protocol-buffers/docs/proto3#json
+//
+// Deprecated: Custom types should implement protobuf reflection instead.
+type JSONPBMarshaler interface {
+	MarshalJSONPB(*Marshaler) ([]byte, error)
+}
+
+// Marshal serializes a protobuf message as JSON into w.
+func (jm *Marshaler) Marshal(w io.Writer, m proto.Message) error {
+	b, err := jm.marshal(m)
+	if len(b) > 0 {
+		if _, err := w.Write(b); err != nil {
+			return err
+		}
+	}
+	return err
+}
+
+// MarshalToString serializes a protobuf message as JSON in string form.
+func (jm *Marshaler) MarshalToString(m proto.Message) (string, error) {
+	b, err := jm.marshal(m)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}
+
+func (jm *Marshaler) marshal(m proto.Message) ([]byte, error) {
+	v := reflect.ValueOf(m)
+	if m == nil || (v.Kind() == reflect.Ptr && v.IsNil()) {
+		return nil, errors.New("Marshal called with nil")
+	}
+
+	// Check for custom marshalers first since they may not properly
+	// implement protobuf reflection that the logic below relies on.
+	if jsm, ok := m.(JSONPBMarshaler); ok {
+		return jsm.MarshalJSONPB(jm)
+	}
+
+	if wrapJSONMarshalV2 {
+		opts := protojson.MarshalOptions{
+			UseProtoNames:   jm.OrigName,
+			UseEnumNumbers:  jm.EnumsAsInts,
+			EmitUnpopulated: jm.EmitDefaults,
+			Indent:          jm.Indent,
+		}
+		if jm.AnyResolver != nil {
+			opts.Resolver = anyResolver{jm.AnyResolver}
+		}
+		return opts.Marshal(proto.MessageReflect(m).Interface())
+	} else {
+		// Check for unpopulated required fields first.
+		m2 := proto.MessageReflect(m)
+		if err := protoV2.CheckInitialized(m2.Interface()); err != nil {
+			return nil, err
+		}
+
+		w := jsonWriter{Marshaler: jm}
+		err := w.marshalMessage(m2, "", "")
+		return w.buf, err
+	}
+}
+
+type jsonWriter struct {
+	*Marshaler
+	buf []byte
+}
+
+func (w *jsonWriter) write(s string) {
+	w.buf = append(w.buf, s...)
+}
+
+func (w *jsonWriter) marshalMessage(m protoreflect.Message, indent, typeURL string) error {
+	if jsm, ok := proto.MessageV1(m.Interface()).(JSONPBMarshaler); ok {
+		b, err := jsm.MarshalJSONPB(w.Marshaler)
+		if err != nil {
+			return err
+		}
+		if typeURL != "" {
+			// we are marshaling this object to an Any type
+			var js map[string]*json.RawMessage
+			if err = json.Unmarshal(b, &js); err != nil {
+				return fmt.Errorf("type %T produced invalid JSON: %v", m.Interface(), err)
+			}
+			turl, err := json.Marshal(typeURL)
+			if err != nil {
+				return fmt.Errorf("failed to marshal type URL %q to JSON: %v", typeURL, err)
+			}
+			js["@type"] = (*json.RawMessage)(&turl)
+			if b, err = json.Marshal(js); err != nil {
+				return err
+			}
+		}
+		w.write(string(b))
+		return nil
+	}
+
+	md := m.Descriptor()
+	fds := md.Fields()
+
+	// Handle well-known types.
+	const secondInNanos = int64(time.Second / time.Nanosecond)
+	switch wellKnownType(md.FullName()) {
+	case "Any":
+		return w.marshalAny(m, indent)
+	case "BoolValue", "BytesValue", "StringValue",
+		"Int32Value", "UInt32Value", "FloatValue",
+		"Int64Value", "UInt64Value", "DoubleValue":
+		fd := fds.ByNumber(1)
+		return w.marshalValue(fd, m.Get(fd), indent)
+	case "Duration":
+		const maxSecondsInDuration = 315576000000
+		// "Generated output always contains 0, 3, 6, or 9 fractional digits,
+		//  depending on required precision."
+		s := m.Get(fds.ByNumber(1)).Int()
+		ns := m.Get(fds.ByNumber(2)).Int()
+		if s < -maxSecondsInDuration || s > maxSecondsInDuration {
+			return fmt.Errorf("seconds out of range %v", s)
+		}
+		if ns <= -secondInNanos || ns >= secondInNanos {
+			return fmt.Errorf("ns out of range (%v, %v)", -secondInNanos, secondInNanos)
+		}
+		if (s > 0 && ns < 0) || (s < 0 && ns > 0) {
+			return errors.New("signs of seconds and nanos do not match")
+		}
+		var sign string
+		if s < 0 || ns < 0 {
+			sign, s, ns = "-", -1*s, -1*ns
+		}
+		x := fmt.Sprintf("%s%d.%09d", sign, s, ns)
+		x = strings.TrimSuffix(x, "000")
+		x = strings.TrimSuffix(x, "000")
+		x = strings.TrimSuffix(x, ".000")
+		w.write(fmt.Sprintf(`"%vs"`, x))
+		return nil
+	case "Timestamp":
+		// "RFC 3339, where generated output will always be Z-normalized
+		//  and uses 0, 3, 6 or 9 fractional digits."
+		s := m.Get(fds.ByNumber(1)).Int()
+		ns := m.Get(fds.ByNumber(2)).Int()
+		if ns < 0 || ns >= secondInNanos {
+			return fmt.Errorf("ns out of range [0, %v)", secondInNanos)
+		}
+		t := time.Unix(s, ns).UTC()
+		// time.RFC3339Nano isn't exactly right (we need to get 3/6/9 fractional digits).
+		x := t.Format("2006-01-02T15:04:05.000000000")
+		x = strings.TrimSuffix(x, "000")
+		x = strings.TrimSuffix(x, "000")
+		x = strings.TrimSuffix(x, ".000")
+		w.write(fmt.Sprintf(`"%vZ"`, x))
+		return nil
+	case "Value":
+		// JSON value; which is a null, number, string, bool, object, or array.
+		od := md.Oneofs().Get(0)
+		fd := m.WhichOneof(od)
+		if fd == nil {
+			return errors.New("nil Value")
+		}
+		return w.marshalValue(fd, m.Get(fd), indent)
+	case "Struct", "ListValue":
+		// JSON object or array.
+		fd := fds.ByNumber(1)
+		return w.marshalValue(fd, m.Get(fd), indent)
+	}
+
+	w.write("{")
+	if w.Indent != "" {
+		w.write("\n")
+	}
+
+	firstField := true
+	if typeURL != "" {
+		if err := w.marshalTypeURL(indent, typeURL); err != nil {
+			return err
+		}
+		firstField = false
+	}
+
+	for i := 0; i < fds.Len(); {
+		fd := fds.Get(i)
+		if od := fd.ContainingOneof(); od != nil {
+			fd = m.WhichOneof(od)
+			i += od.Fields().Len()
+			if fd == nil {
+				continue
+			}
+		} else {
+			i++
+		}
+
+		v := m.Get(fd)
+
+		if !m.Has(fd) {
+			if !w.EmitDefaults || fd.ContainingOneof() != nil {
+				continue
+			}
+			if fd.Cardinality() != protoreflect.Repeated && (fd.Message() != nil || fd.Syntax() == protoreflect.Proto2) {
+				v = protoreflect.Value{} // use "null" for singular messages or proto2 scalars
+			}
+		}
+
+		if !firstField {
+			w.writeComma()
+		}
+		if err := w.marshalField(fd, v, indent); err != nil {
+			return err
+		}
+		firstField = false
+	}
+
+	// Handle proto2 extensions.
+	if md.ExtensionRanges().Len() > 0 {
+		// Collect a sorted list of all extension descriptor and values.
+		type ext struct {
+			desc protoreflect.FieldDescriptor
+			val  protoreflect.Value
+		}
+		var exts []ext
+		m.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
+			if fd.IsExtension() {
+				exts = append(exts, ext{fd, v})
+			}
+			return true
+		})
+		sort.Slice(exts, func(i, j int) bool {
+			return exts[i].desc.Number() < exts[j].desc.Number()
+		})
+
+		for _, ext := range exts {
+			if !firstField {
+				w.writeComma()
+			}
+			if err := w.marshalField(ext.desc, ext.val, indent); err != nil {
+				return err
+			}
+			firstField = false
+		}
+	}
+
+	if w.Indent != "" {
+		w.write("\n")
+		w.write(indent)
+	}
+	w.write("}")
+	return nil
+}
+
+func (w *jsonWriter) writeComma() {
+	if w.Indent != "" {
+		w.write(",\n")
+	} else {
+		w.write(",")
+	}
+}
+
+func (w *jsonWriter) marshalAny(m protoreflect.Message, indent string) error {
+	// "If the Any contains a value that has a special JSON mapping,
+	//  it will be converted as follows: {"@type": xxx, "value": yyy}.
+	//  Otherwise, the value will be converted into a JSON object,
+	//  and the "@type" field will be inserted to indicate the actual data type."
+	md := m.Descriptor()
+	typeURL := m.Get(md.Fields().ByNumber(1)).String()
+	rawVal := m.Get(md.Fields().ByNumber(2)).Bytes()
+
+	var m2 protoreflect.Message
+	if w.AnyResolver != nil {
+		mi, err := w.AnyResolver.Resolve(typeURL)
+		if err != nil {
+			return err
+		}
+		m2 = proto.MessageReflect(mi)
+	} else {
+		mt, err := protoregistry.GlobalTypes.FindMessageByURL(typeURL)
+		if err != nil {
+			return err
+		}
+		m2 = mt.New()
+	}
+
+	if err := protoV2.Unmarshal(rawVal, m2.Interface()); err != nil {
+		return err
+	}
+
+	if wellKnownType(m2.Descriptor().FullName()) == "" {
+		return w.marshalMessage(m2, indent, typeURL)
+	}
+
+	w.write("{")
+	if w.Indent != "" {
+		w.write("\n")
+	}
+	if err := w.marshalTypeURL(indent, typeURL); err != nil {
+		return err
+	}
+	w.writeComma()
+	if w.Indent != "" {
+		w.write(indent)
+		w.write(w.Indent)
+		w.write(`"value": `)
+	} else {
+		w.write(`"value":`)
+	}
+	if err := w.marshalMessage(m2, indent+w.Indent, ""); err != nil {
+		return err
+	}
+	if w.Indent != "" {
+		w.write("\n")
+		w.write(indent)
+	}
+	w.write("}")
+	return nil
+}
+
+func (w *jsonWriter) marshalTypeURL(indent, typeURL string) error {
+	if w.Indent != "" {
+		w.write(indent)
+		w.write(w.Indent)
+	}
+	w.write(`"@type":`)
+	if w.Indent != "" {
+		w.write(" ")
+	}
+	b, err := json.Marshal(typeURL)
+	if err != nil {
+		return err
+	}
+	w.write(string(b))
+	return nil
+}
+
+// marshalField writes field description and value to the Writer.
+func (w *jsonWriter) marshalField(fd protoreflect.FieldDescriptor, v protoreflect.Value, indent string) error {
+	if w.Indent != "" {
+		w.write(indent)
+		w.write(w.Indent)
+	}
+	w.write(`"`)
+	switch {
+	case fd.IsExtension():
+		// For message set, use the fname of the message as the extension name.
+		name := string(fd.FullName())
+		if isMessageSet(fd.ContainingMessage()) {
+			name = strings.TrimSuffix(name, ".message_set_extension")
+		}
+
+		w.write("[" + name + "]")
+	case w.OrigName:
+		name := string(fd.Name())
+		if fd.Kind() == protoreflect.GroupKind {
+			name = string(fd.Message().Name())
+		}
+		w.write(name)
+	default:
+		w.write(string(fd.JSONName()))
+	}
+	w.write(`":`)
+	if w.Indent != "" {
+		w.write(" ")
+	}
+	return w.marshalValue(fd, v, indent)
+}
+
+func (w *jsonWriter) marshalValue(fd protoreflect.FieldDescriptor, v protoreflect.Value, indent string) error {
+	switch {
+	case fd.IsList():
+		w.write("[")
+		comma := ""
+		lv := v.List()
+		for i := 0; i < lv.Len(); i++ {
+			w.write(comma)
+			if w.Indent != "" {
+				w.write("\n")
+				w.write(indent)
+				w.write(w.Indent)
+				w.write(w.Indent)
+			}
+			if err := w.marshalSingularValue(fd, lv.Get(i), indent+w.Indent); err != nil {
+				return err
+			}
+			comma = ","
+		}
+		if w.Indent != "" {
+			w.write("\n")
+			w.write(indent)
+			w.write(w.Indent)
+		}
+		w.write("]")
+		return nil
+	case fd.IsMap():
+		kfd := fd.MapKey()
+		vfd := fd.MapValue()
+		mv := v.Map()
+
+		// Collect a sorted list of all map keys and values.
+		type entry struct{ key, val protoreflect.Value }
+		var entries []entry
+		mv.Range(func(k protoreflect.MapKey, v protoreflect.Value) bool {
+			entries = append(entries, entry{k.Value(), v})
+			return true
+		})
+		sort.Slice(entries, func(i, j int) bool {
+			switch kfd.Kind() {
+			case protoreflect.BoolKind:
+				return !entries[i].key.Bool() && entries[j].key.Bool()
+			case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind, protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Sfixed64Kind:
+				return entries[i].key.Int() < entries[j].key.Int()
+			case protoreflect.Uint32Kind, protoreflect.Fixed32Kind, protoreflect.Uint64Kind, protoreflect.Fixed64Kind:
+				return entries[i].key.Uint() < entries[j].key.Uint()
+			case protoreflect.StringKind:
+				return entries[i].key.String() < entries[j].key.String()
+			default:
+				panic("invalid kind")
+			}
+		})
+
+		w.write(`{`)
+		comma := ""
+		for _, entry := range entries {
+			w.write(comma)
+			if w.Indent != "" {
+				w.write("\n")
+				w.write(indent)
+				w.write(w.Indent)
+				w.write(w.Indent)
+			}
+
+			s := fmt.Sprint(entry.key.Interface())
+			b, err := json.Marshal(s)
+			if err != nil {
+				return err
+			}
+			w.write(string(b))
+
+			w.write(`:`)
+			if w.Indent != "" {
+				w.write(` `)
+			}
+
+			if err := w.marshalSingularValue(vfd, entry.val, indent+w.Indent); err != nil {
+				return err
+			}
+			comma = ","
+		}
+		if w.Indent != "" {
+			w.write("\n")
+			w.write(indent)
+			w.write(w.Indent)
+		}
+		w.write(`}`)
+		return nil
+	default:
+		return w.marshalSingularValue(fd, v, indent)
+	}
+}
+
+func (w *jsonWriter) marshalSingularValue(fd protoreflect.FieldDescriptor, v protoreflect.Value, indent string) error {
+	switch {
+	case !v.IsValid():
+		w.write("null")
+		return nil
+	case fd.Message() != nil:
+		return w.marshalMessage(v.Message(), indent+w.Indent, "")
+	case fd.Enum() != nil:
+		if fd.Enum().FullName() == "google.protobuf.NullValue" {
+			w.write("null")
+			return nil
+		}
+
+		vd := fd.Enum().Values().ByNumber(v.Enum())
+		if vd == nil || w.EnumsAsInts {
+			w.write(strconv.Itoa(int(v.Enum())))
+		} else {
+			w.write(`"` + string(vd.Name()) + `"`)
+		}
+		return nil
+	default:
+		switch v.Interface().(type) {
+		case float32, float64:
+			switch {
+			case math.IsInf(v.Float(), +1):
+				w.write(`"Infinity"`)
+				return nil
+			case math.IsInf(v.Float(), -1):
+				w.write(`"-Infinity"`)
+				return nil
+			case math.IsNaN(v.Float()):
+				w.write(`"NaN"`)
+				return nil
+			}
+		case int64, uint64:
+			w.write(fmt.Sprintf(`"%d"`, v.Interface()))
+			return nil
+		}
+
+		b, err := json.Marshal(v.Interface())
+		if err != nil {
+			return err
+		}
+		w.write(string(b))
+		return nil
+	}
+}
@@ -0,0 +1,69 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package jsonpb provides functionality to marshal and unmarshal between a
+// protocol buffer message and JSON. It follows the specification at
+// https://developers.google.com/protocol-buffers/docs/proto3#json.
+//
+// Do not rely on the default behavior of the standard encoding/json package
+// when called on generated message types as it does not operate correctly.
+//
+// Deprecated: Use the "google.golang.org/protobuf/encoding/protojson"
+// package instead.
+package jsonpb
+
+import (
+	"github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+	"google.golang.org/protobuf/runtime/protoimpl"
+)
+
+// AnyResolver takes a type URL, present in an Any message,
+// and resolves it into an instance of the associated message.
+type AnyResolver interface {
+	Resolve(typeURL string) (proto.Message, error)
+}
+
+type anyResolver struct{ AnyResolver }
+
+func (r anyResolver) FindMessageByName(message protoreflect.FullName) (protoreflect.MessageType, error) {
+	return r.FindMessageByURL(string(message))
+}
+
+func (r anyResolver) FindMessageByURL(url string) (protoreflect.MessageType, error) {
+	m, err := r.Resolve(url)
+	if err != nil {
+		return nil, err
+	}
+	return protoimpl.X.MessageTypeOf(m), nil
+}
+
+func (r anyResolver) FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error) {
+	return protoregistry.GlobalTypes.FindExtensionByName(field)
+}
+
+func (r anyResolver) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {
+	return protoregistry.GlobalTypes.FindExtensionByNumber(message, field)
+}
+
+func wellKnownType(s protoreflect.FullName) string {
+	if s.Parent() == "google.protobuf" {
+		switch s.Name() {
+		case "Empty", "Any",
+			"BoolValue", "BytesValue", "StringValue",
+			"Int32Value", "UInt32Value", "FloatValue",
+			"Int64Value", "UInt64Value", "DoubleValue",
+			"Duration", "Timestamp",
+			"NullValue", "Struct", "Value", "ListValue":
+			return string(s.Name())
+		}
+	}
+	return ""
+}
+
+func isMessageSet(md protoreflect.MessageDescriptor) bool {
+	ms, ok := md.(interface{ IsMessageSet() bool })
+	return ok && ms.IsMessageSet()
+}
@@ -1,3 +0,0 @@
-# This source code refers to The Go Authors for copyright purposes.
-# The master list of authors is in the main Go distribution,
-# visible at http://tip.golang.org/AUTHORS.
@@ -1,3 +0,0 @@
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at http://tip.golang.org/CONTRIBUTORS.
@@ -8,22 +8,35 @@ package errgroup

 import (
 	"context"
+	"fmt"
 	"sync"
 )

+type token struct{}
+
 // A Group is a collection of goroutines working on subtasks that are part of
 // the same overall task.
 //
-// A zero Group is valid and does not cancel on error.
+// A zero Group is valid, has no limit on the number of active goroutines,
+// and does not cancel on error.
 type Group struct {
 	cancel func()

 	wg sync.WaitGroup

+	sem chan token
+
 	errOnce sync.Once
 	err     error
 }

+func (g *Group) done() {
+	if g.sem != nil {
+		<-g.sem
+	}
+	g.wg.Done()
+}
+
 // WithContext returns a new Group and an associated Context derived from ctx.
 //
 // The derived Context is canceled the first time a function passed to Go
@@ -45,14 +58,19 @@ func (g *Group) Wait() error {
 }

 // Go calls the given function in a new goroutine.
+// It blocks until the new goroutine can be added without the number of
+// active goroutines in the group exceeding the configured limit.
 //
 // The first call to return a non-nil error cancels the group; its error will be
 // returned by Wait.
 func (g *Group) Go(f func() error) {
-	g.wg.Add(1)
+	if g.sem != nil {
+		g.sem <- token{}
+	}

+	g.wg.Add(1)
 	go func() {
-		defer g.wg.Done()
+		defer g.done()

 		if err := f(); err != nil {
 			g.errOnce.Do(func() {
@@ -64,3 +82,51 @@ func (g *Group) Go(f func() error) {
 		}
 	}()
 }
+
+// TryGo calls the given function in a new goroutine only if the number of
+// active goroutines in the group is currently below the configured limit.
+//
+// The return value reports whether the goroutine was started.
+func (g *Group) TryGo(f func() error) bool {
+	if g.sem != nil {
+		select {
+		case g.sem <- token{}:
+			// Note: this allows barging iff channels in general allow barging.
+		default:
+			return false
+		}
+	}
+
+	g.wg.Add(1)
+	go func() {
+		defer g.done()
+
+		if err := f(); err != nil {
+			g.errOnce.Do(func() {
+				g.err = err
+				if g.cancel != nil {
+					g.cancel()
+				}
+			})
+		}
+	}()
+	return true
+}
+
+// SetLimit limits the number of active goroutines in this group to at most n.
+// A negative value indicates no limit.
+//
+// Any subsequent call to the Go method will block until it can add an active
+// goroutine without exceeding the configured limit.
+//
+// The limit must not be modified while any goroutines in the group are active.
+func (g *Group) SetLimit(n int) {
+	if n < 0 {
+		g.sem = nil
+		return
+	}
+	if len(g.sem) != 0 {
+		panic(fmt.Errorf("errgroup: modify limit while %v goroutines in the group are still active", len(g.sem)))
+	}
+	g.sem = make(chan token, n)
+}
@@ -5,7 +5,8 @@
 // Package xerrors implements functions to manipulate errors.
 //
 // This package is based on the Go 2 proposal for error values:
-//   https://golang.org/design/29934-error-values
+//
+//	https://golang.org/design/29934-error-values
 //
 // These functions were incorporated into the standard library's errors package
 // in Go 1.13:
@@ -33,6 +33,9 @@ const percentBangString = "%!"
 // It is invalid to include more than one %w verb or to supply it with an
 // operand that does not implement the error interface. The %w verb is otherwise
 // a synonym for %v.
+//
+// Note that as of Go 1.13, the fmt.Errorf function will do error formatting,
+// but it will not capture a stack backtrace.
 func Errorf(format string, a ...interface{}) error {
 	format = formatPlusW(format)
 	// Support a ": %[wsv]" suffix, which works well with xerrors.Formatter.
@@ -35,6 +35,8 @@ func (e noWrapper) FormatError(p Printer) (next error) {

 // Unwrap returns the result of calling the Unwrap method on err, if err implements
 // Unwrap. Otherwise, Unwrap returns nil.
+//
+// Deprecated: As of Go 1.13, use errors.Unwrap instead.
 func Unwrap(err error) error {
 	u, ok := err.(Wrapper)
 	if !ok {
@@ -47,6 +49,8 @@ func Unwrap(err error) error {
 //
 // An error is considered to match a target if it is equal to that target or if
 // it implements a method Is(error) bool such that Is(target) returns true.
+//
+// Deprecated: As of Go 1.13, use errors.Is instead.
 func Is(err, target error) bool {
 	if target == nil {
 		return err == target
@@ -77,6 +81,8 @@ func Is(err, target error) bool {
 //
 // The As method should set the target to its value and return true if err
 // matches the type to which target points.
+//
+// Deprecated: As of Go 1.13, use errors.As instead.
 func As(err error, target interface{}) bool {
 	if target == nil {
 		panic("errors: target cannot be nil")
@@ -27,6 +27,7 @@ import (
 	"net"
 	"strings"

+	"google.golang.org/grpc/channelz"
 	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/internal"
@@ -192,7 +193,7 @@ type BuildOptions struct {
 	// server can ignore this field.
 	Authority string
 	// ChannelzParentID is the parent ClientConn's channelz ID.
-	ChannelzParentID int64
+	ChannelzParentID *channelz.Identifier
 	// CustomUserAgent is the custom user agent set on the parent ClientConn.
 	// The balancer should set the same custom user agent if it creates a
 	// ClientConn.
@@ -20,130 +20,178 @@ package grpc

 import (
 	"fmt"
+	"strings"
 	"sync"

 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/internal/balancer/gracefulswitch"
 	"google.golang.org/grpc/internal/buffer"
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcsync"
 	"google.golang.org/grpc/resolver"
 )

-// scStateUpdate contains the subConn and the new state it changed to.
+// ccBalancerWrapper sits between the ClientConn and the Balancer.
+//
+// ccBalancerWrapper implements methods corresponding to the ones on the
+// balancer.Balancer interface. The ClientConn is free to call these methods
+// concurrently and the ccBalancerWrapper ensures that calls from the ClientConn
+// to the Balancer happen synchronously and in order.
+//
+// ccBalancerWrapper also implements the balancer.ClientConn interface and is
+// passed to the Balancer implementations. It invokes unexported methods on the
+// ClientConn to handle these calls from the Balancer.
+//
+// It uses the gracefulswitch.Balancer internally to ensure that balancer
+// switches happen in a graceful manner.
+type ccBalancerWrapper struct {
+	cc *ClientConn
+
+	// Since these fields are accessed only from handleXxx() methods which are
+	// synchronized by the watcher goroutine, we do not need a mutex to protect
+	// these fields.
+	balancer        *gracefulswitch.Balancer
+	curBalancerName string
+
+	updateCh *buffer.Unbounded // Updates written on this channel are processed by watcher().
+	resultCh *buffer.Unbounded // Results of calls to UpdateClientConnState() are pushed here.
+	closed   *grpcsync.Event   // Indicates if close has been called.
+	done     *grpcsync.Event   // Indicates if close has completed its work.
+}
+
+// newCCBalancerWrapper creates a new balancer wrapper. The underlying balancer
+// is not created until the switchTo() method is invoked.
+func newCCBalancerWrapper(cc *ClientConn, bopts balancer.BuildOptions) *ccBalancerWrapper {
+	ccb := &ccBalancerWrapper{
+		cc:       cc,
+		updateCh: buffer.NewUnbounded(),
+		resultCh: buffer.NewUnbounded(),
+		closed:   grpcsync.NewEvent(),
+		done:     grpcsync.NewEvent(),
+	}
+	go ccb.watcher()
+	ccb.balancer = gracefulswitch.NewBalancer(ccb, bopts)
+	return ccb
+}
+
+// The following xxxUpdate structs wrap the arguments received as part of the
+// corresponding update. The watcher goroutine uses the 'type' of the update to
+// invoke the appropriate handler routine to handle the update.
+
+type ccStateUpdate struct {
+	ccs *balancer.ClientConnState
+}
+
 type scStateUpdate struct {
 	sc    balancer.SubConn
 	state connectivity.State
 	err   error
 }

-// exitIdle contains no data and is just a signal sent on the updateCh in
-// ccBalancerWrapper to instruct the balancer to exit idle.
-type exitIdle struct{}
+type exitIdleUpdate struct{}

-// ccBalancerWrapper is a wrapper on top of cc for balancers.
-// It implements balancer.ClientConn interface.
-type ccBalancerWrapper struct {
-	cc          *ClientConn
-	balancerMu  sync.Mutex // synchronizes calls to the balancer
-	balancer    balancer.Balancer
-	hasExitIdle bool
-	updateCh    *buffer.Unbounded
-	closed      *grpcsync.Event
-	done        *grpcsync.Event
-
-	mu       sync.Mutex
-	subConns map[*acBalancerWrapper]struct{}
+type resolverErrorUpdate struct {
+	err error
 }

-func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.BuildOptions) *ccBalancerWrapper {
-	ccb := &ccBalancerWrapper{
-		cc:       cc,
-		updateCh: buffer.NewUnbounded(),
-		closed:   grpcsync.NewEvent(),
-		done:     grpcsync.NewEvent(),
-		subConns: make(map[*acBalancerWrapper]struct{}),
-	}
-	go ccb.watcher()
-	ccb.balancer = b.Build(ccb, bopts)
-	_, ccb.hasExitIdle = ccb.balancer.(balancer.ExitIdler)
-	return ccb
+type switchToUpdate struct {
+	name string
 }

-// watcher balancer functions sequentially, so the balancer can be implemented
-// lock-free.
+type subConnUpdate struct {
+	acbw *acBalancerWrapper
+}
+
+// watcher is a long-running goroutine which reads updates from a channel and
+// invokes corresponding methods on the underlying balancer. It ensures that
+// these methods are invoked in a synchronous fashion. It also ensures that
+// these methods are invoked in the order in which the updates were received.
 func (ccb *ccBalancerWrapper) watcher() {
 	for {
 		select {
-		case t := <-ccb.updateCh.Get():
+		case u := <-ccb.updateCh.Get():
 			ccb.updateCh.Load()
 			if ccb.closed.HasFired() {
 				break
 			}
-			switch u := t.(type) {
+			switch update := u.(type) {
+			case *ccStateUpdate:
+				ccb.handleClientConnStateChange(update.ccs)
 			case *scStateUpdate:
-				ccb.balancerMu.Lock()
-				ccb.balancer.UpdateSubConnState(u.sc, balancer.SubConnState{ConnectivityState: u.state, ConnectionError: u.err})
-				ccb.balancerMu.Unlock()
-			case *acBalancerWrapper:
-				ccb.mu.Lock()
-				if ccb.subConns != nil {
-					delete(ccb.subConns, u)
-					ccb.cc.removeAddrConn(u.getAddrConn(), errConnDrain)
-				}
-				ccb.mu.Unlock()
-			case exitIdle:
-				if ccb.cc.GetState() == connectivity.Idle {
-					if ei, ok := ccb.balancer.(balancer.ExitIdler); ok {
-						// We already checked that the balancer implements
-						// ExitIdle before pushing the event to updateCh, but
-						// check conditionally again as defensive programming.
-						ccb.balancerMu.Lock()
-						ei.ExitIdle()
-						ccb.balancerMu.Unlock()
-					}
-				}
+				ccb.handleSubConnStateChange(update)
+			case *exitIdleUpdate:
+				ccb.handleExitIdle()
+			case *resolverErrorUpdate:
+				ccb.handleResolverError(update.err)
+			case *switchToUpdate:
+				ccb.handleSwitchTo(update.name)
+			case *subConnUpdate:
+				ccb.handleRemoveSubConn(update.acbw)
 			default:
-				logger.Errorf("ccBalancerWrapper.watcher: unknown update %+v, type %T", t, t)
+				logger.Errorf("ccBalancerWrapper.watcher: unknown update %+v, type %T", update, update)
 			}
 		case <-ccb.closed.Done():
 		}

 		if ccb.closed.HasFired() {
-			ccb.balancerMu.Lock()
-			ccb.balancer.Close()
-			ccb.balancerMu.Unlock()
-			ccb.mu.Lock()
-			scs := ccb.subConns
-			ccb.subConns = nil
-			ccb.mu.Unlock()
-			ccb.UpdateState(balancer.State{ConnectivityState: connectivity.Connecting, Picker: nil})
-			ccb.done.Fire()
-			// Fire done before removing the addr conns.  We can safely unblock
-			// ccb.close and allow the removeAddrConns to happen
-			// asynchronously.
-			for acbw := range scs {
-				ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
-			}
+			ccb.handleClose()
 			return
 		}
 	}
 }

-func (ccb *ccBalancerWrapper) close() {
-	ccb.closed.Fire()
-	<-ccb.done.Done()
-}
+// updateClientConnState is invoked by grpc to push a ClientConnState update to
+// the underlying balancer.
+//
+// Unlike other methods invoked by grpc to push updates to the underlying
+// balancer, this method cannot simply push the update onto the update channel
+// and return. It needs to return the error returned by the underlying balancer
+// back to grpc which propagates that to the resolver.
+func (ccb *ccBalancerWrapper) updateClientConnState(ccs *balancer.ClientConnState) error {
+	ccb.updateCh.Put(&ccStateUpdate{ccs: ccs})

-func (ccb *ccBalancerWrapper) exitIdle() bool {
-	if !ccb.hasExitIdle {
-		return false
+	var res interface{}
+	select {
+	case res = <-ccb.resultCh.Get():
+		ccb.resultCh.Load()
+	case <-ccb.closed.Done():
+		// Return early if the balancer wrapper is closed while we are waiting for
+		// the underlying balancer to process a ClientConnState update.
+		return nil
 	}
-	ccb.updateCh.Put(exitIdle{})
-	return true
+	// If the returned error is nil, attempting to type assert to error leads to
+	// panic. So, this needs to handled separately.
+	if res == nil {
+		return nil
+	}
+	return res.(error)
 }

-func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State, err error) {
+// handleClientConnStateChange handles a ClientConnState update from the update
+// channel and invokes the appropriate method on the underlying balancer.
+//
+// If the addresses specified in the update contain addresses of type "grpclb"
+// and the selected LB policy is not "grpclb", these addresses will be filtered
+// out and ccs will be modified with the updated address list.
+func (ccb *ccBalancerWrapper) handleClientConnStateChange(ccs *balancer.ClientConnState) {
+	if ccb.curBalancerName != grpclbName {
+		// Filter any grpclb addresses since we don't have the grpclb balancer.
+		var addrs []resolver.Address
+		for _, addr := range ccs.ResolverState.Addresses {
+			if addr.Type == resolver.GRPCLB {
+				continue
+			}
+			addrs = append(addrs, addr)
+		}
+		ccs.ResolverState.Addresses = addrs
+	}
+	ccb.resultCh.Put(ccb.balancer.UpdateClientConnState(*ccs))
+}
+
+// updateSubConnState is invoked by grpc to push a subConn state update to the
+// underlying balancer.
+func (ccb *ccBalancerWrapper) updateSubConnState(sc balancer.SubConn, s connectivity.State, err error) {
 	// When updating addresses for a SubConn, if the address in use is not in
 	// the new addresses, the old ac will be tearDown() and a new ac will be
 	// created. tearDown() generates a state change with Shutdown state, we
@@ -161,44 +209,125 @@ func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s co
 	})
 }

-func (ccb *ccBalancerWrapper) updateClientConnState(ccs *balancer.ClientConnState) error {
-	ccb.balancerMu.Lock()
-	defer ccb.balancerMu.Unlock()
-	return ccb.balancer.UpdateClientConnState(*ccs)
+// handleSubConnStateChange handles a SubConnState update from the update
+// channel and invokes the appropriate method on the underlying balancer.
+func (ccb *ccBalancerWrapper) handleSubConnStateChange(update *scStateUpdate) {
+	ccb.balancer.UpdateSubConnState(update.sc, balancer.SubConnState{ConnectivityState: update.state, ConnectionError: update.err})
+}
+
+func (ccb *ccBalancerWrapper) exitIdle() {
+	ccb.updateCh.Put(&exitIdleUpdate{})
+}
+
+func (ccb *ccBalancerWrapper) handleExitIdle() {
+	if ccb.cc.GetState() != connectivity.Idle {
+		return
+	}
+	ccb.balancer.ExitIdle()
 }

 func (ccb *ccBalancerWrapper) resolverError(err error) {
-	ccb.balancerMu.Lock()
-	defer ccb.balancerMu.Unlock()
+	ccb.updateCh.Put(&resolverErrorUpdate{err: err})
+}
+
+func (ccb *ccBalancerWrapper) handleResolverError(err error) {
 	ccb.balancer.ResolverError(err)
 }

+// switchTo is invoked by grpc to instruct the balancer wrapper to switch to the
+// LB policy identified by name.
+//
+// ClientConn calls newCCBalancerWrapper() at creation time. Upon receipt of the
+// first good update from the name resolver, it determines the LB policy to use
+// and invokes the switchTo() method. Upon receipt of every subsequent update
+// from the name resolver, it invokes this method.
+//
+// the ccBalancerWrapper keeps track of the current LB policy name, and skips
+// the graceful balancer switching process if the name does not change.
+func (ccb *ccBalancerWrapper) switchTo(name string) {
+	ccb.updateCh.Put(&switchToUpdate{name: name})
+}
+
+// handleSwitchTo handles a balancer switch update from the update channel. It
+// calls the SwitchTo() method on the gracefulswitch.Balancer with a
+// balancer.Builder corresponding to name. If no balancer.Builder is registered
+// for the given name, it uses the default LB policy which is "pick_first".
+func (ccb *ccBalancerWrapper) handleSwitchTo(name string) {
+	// TODO: Other languages use case-insensitive balancer registries. We should
+	// switch as well. See: https://github.com/grpc/grpc-go/issues/5288.
+	if strings.EqualFold(ccb.curBalancerName, name) {
+		return
+	}
+
+	// TODO: Ensure that name is a registered LB policy when we get here.
+	// We currently only validate the `loadBalancingConfig` field. We need to do
+	// the same for the `loadBalancingPolicy` field and reject the service config
+	// if the specified policy is not registered.
+	builder := balancer.Get(name)
+	if builder == nil {
+		channelz.Warningf(logger, ccb.cc.channelzID, "Channel switches to new LB policy %q, since the specified LB policy %q was not registered", PickFirstBalancerName, name)
+		builder = newPickfirstBuilder()
+	} else {
+		channelz.Infof(logger, ccb.cc.channelzID, "Channel switches to new LB policy %q", name)
+	}
+
+	if err := ccb.balancer.SwitchTo(builder); err != nil {
+		channelz.Errorf(logger, ccb.cc.channelzID, "Channel failed to build new LB policy %q: %v", name, err)
+		return
+	}
+	ccb.curBalancerName = builder.Name()
+}
+
+// handleRemoveSucConn handles a request from the underlying balancer to remove
+// a subConn.
+//
+// See comments in RemoveSubConn() for more details.
+func (ccb *ccBalancerWrapper) handleRemoveSubConn(acbw *acBalancerWrapper) {
+	ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
+}
+
+func (ccb *ccBalancerWrapper) close() {
+	ccb.closed.Fire()
+	<-ccb.done.Done()
+}
+
+func (ccb *ccBalancerWrapper) handleClose() {
+	ccb.balancer.Close()
+	ccb.done.Fire()
+}
+
 func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) {
 	if len(addrs) <= 0 {
 		return nil, fmt.Errorf("grpc: cannot create SubConn with empty address list")
 	}
-	ccb.mu.Lock()
-	defer ccb.mu.Unlock()
-	if ccb.subConns == nil {
-		return nil, fmt.Errorf("grpc: ClientConn balancer wrapper was closed")
-	}
 	ac, err := ccb.cc.newAddrConn(addrs, opts)
 	if err != nil {
+		channelz.Warningf(logger, ccb.cc.channelzID, "acBalancerWrapper: NewSubConn: failed to newAddrConn: %v", err)
 		return nil, err
 	}
 	acbw := &acBalancerWrapper{ac: ac}
 	acbw.ac.mu.Lock()
 	ac.acbw = acbw
 	acbw.ac.mu.Unlock()
-	ccb.subConns[acbw] = struct{}{}
 	return acbw, nil
 }

 func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) {
-	// The RemoveSubConn() is handled in the run() goroutine, to avoid deadlock
-	// during switchBalancer() if the old balancer calls RemoveSubConn() in its
-	// Close().
-	ccb.updateCh.Put(sc)
+	// Before we switched the ccBalancerWrapper to use gracefulswitch.Balancer, it
+	// was required to handle the RemoveSubConn() method asynchronously by pushing
+	// the update onto the update channel. This was done to avoid a deadlock as
+	// switchBalancer() was holding cc.mu when calling Close() on the old
+	// balancer, which would in turn call RemoveSubConn().
+	//
+	// With the use of gracefulswitch.Balancer in ccBalancerWrapper, handling this
+	// asynchronously is probably not required anymore since the switchTo() method
+	// handles the balancer switch by pushing the update onto the channel.
+	// TODO(easwars): Handle this inline.
+	acbw, ok := sc.(*acBalancerWrapper)
+	if !ok {
+		return
+	}
+	ccb.updateCh.Put(&subConnUpdate{acbw: acbw})
 }

 func (ccb *ccBalancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resolver.Address) {
@@ -210,11 +339,6 @@ func (ccb *ccBalancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resol
 }

 func (ccb *ccBalancerWrapper) UpdateState(s balancer.State) {
-	ccb.mu.Lock()
-	defer ccb.mu.Unlock()
-	if ccb.subConns == nil {
-		return
-	}
 	// Update picker before updating state.  Even though the ordering here does
 	// not matter, it can lead to multiple calls of Pick in the common start-up
 	// case where we wait for ready and then perform an RPC.  If the picker is
@@ -0,0 +1,36 @@
+/*
+ *
+ * Copyright 2020 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package channelz exports internals of the channelz implementation as required
+// by other gRPC packages.
+//
+// The implementation of the channelz spec as defined in
+// https://github.com/grpc/proposal/blob/master/A14-channelz.md, is provided by
+// the `internal/channelz` package.
+//
+// Experimental
+//
+// Notice: All APIs in this package are experimental and may be removed in a
+// later release.
+package channelz
+
+import "google.golang.org/grpc/internal/channelz"
+
+// Identifier is an opaque identifier which uniquely identifies an entity in the
+// channelz database.
+type Identifier = channelz.Identifier
@@ -159,23 +159,20 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		}
 	}()

-	if channelz.IsOn() {
-		if cc.dopts.channelzParentID != 0 {
-			cc.channelzID = channelz.RegisterChannel(&channelzChannel{cc}, cc.dopts.channelzParentID, target)
-			channelz.AddTraceEvent(logger, cc.channelzID, 0, &channelz.TraceEventDesc{
-				Desc:     "Channel Created",
-				Severity: channelz.CtInfo,
-				Parent: &channelz.TraceEventDesc{
-					Desc:     fmt.Sprintf("Nested Channel(id:%d) created", cc.channelzID),
-					Severity: channelz.CtInfo,
-				},
-			})
-		} else {
-			cc.channelzID = channelz.RegisterChannel(&channelzChannel{cc}, 0, target)
-			channelz.Info(logger, cc.channelzID, "Channel Created")
-		}
-		cc.csMgr.channelzID = cc.channelzID
+	pid := cc.dopts.channelzParentID
+	cc.channelzID = channelz.RegisterChannel(&channelzChannel{cc}, pid, target)
+	ted := &channelz.TraceEventDesc{
+		Desc:     "Channel created",
+		Severity: channelz.CtInfo,
 	}
+	if cc.dopts.channelzParentID != nil {
+		ted.Parent = &channelz.TraceEventDesc{
+			Desc:     fmt.Sprintf("Nested Channel(id:%d) created", cc.channelzID.Int()),
+			Severity: channelz.CtInfo,
+		}
+	}
+	channelz.AddTraceEvent(logger, cc.channelzID, 1, ted)
+	cc.csMgr.channelzID = cc.channelzID

 	if cc.dopts.copts.TransportCredentials == nil && cc.dopts.copts.CredsBundle == nil {
 		return nil, errNoTransportSecurity
@@ -281,7 +278,7 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 	if creds := cc.dopts.copts.TransportCredentials; creds != nil {
 		credsClone = creds.Clone()
 	}
-	cc.balancerBuildOpts = balancer.BuildOptions{
+	cc.balancerWrapper = newCCBalancerWrapper(cc, balancer.BuildOptions{
 		DialCreds:        credsClone,
 		CredsBundle:      cc.dopts.copts.CredsBundle,
 		Dialer:           cc.dopts.copts.Dialer,
@@ -289,7 +286,7 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		CustomUserAgent:  cc.dopts.copts.UserAgent,
 		ChannelzParentID: cc.channelzID,
 		Target:           cc.parsedTarget,
-	}
+	})

 	// Build the resolver.
 	rWrapper, err := newCCResolverWrapper(cc, resolverBuilder)
@@ -398,7 +395,7 @@ type connectivityStateManager struct {
 	mu         sync.Mutex
 	state      connectivity.State
 	notifyChan chan struct{}
-	channelzID int64
+	channelzID *channelz.Identifier
 }

 // updateState updates the connectivity.State of ClientConn.
@@ -464,34 +461,36 @@ var _ ClientConnInterface = (*ClientConn)(nil)
 // handshakes. It also handles errors on established connections by
 // re-resolving the name and reconnecting.
 type ClientConn struct {
-	ctx    context.Context
-	cancel context.CancelFunc
+	ctx    context.Context    // Initialized using the background context at dial time.
+	cancel context.CancelFunc // Cancelled on close.

-	target       string
-	parsedTarget resolver.Target
-	authority    string
-	dopts        dialOptions
-	csMgr        *connectivityStateManager
-
-	balancerBuildOpts balancer.BuildOptions
-	blockingpicker    *pickerWrapper
+	// The following are initialized at dial time, and are read-only after that.
+	target          string               // User's dial target.
+	parsedTarget    resolver.Target      // See parseTargetAndFindResolver().
+	authority       string               // See determineAuthority().
+	dopts           dialOptions          // Default and user specified dial options.
+	channelzID      *channelz.Identifier // Channelz identifier for the channel.
+	balancerWrapper *ccBalancerWrapper   // Uses gracefulswitch.balancer underneath.

+	// The following provide their own synchronization, and therefore don't
+	// require cc.mu to be held to access them.
+	csMgr              *connectivityStateManager
+	blockingpicker     *pickerWrapper
 	safeConfigSelector iresolver.SafeConfigSelector
+	czData             *channelzData
+	retryThrottler     atomic.Value // Updated from service config.

-	mu              sync.RWMutex
-	resolverWrapper *ccResolverWrapper
-	sc              *ServiceConfig
-	conns           map[*addrConn]struct{}
-	// Keepalive parameter can be updated if a GoAway is received.
-	mkp             keepalive.ClientParameters
-	curBalancerName string
-	balancerWrapper *ccBalancerWrapper
-	retryThrottler  atomic.Value
-
+	// firstResolveEvent is used to track whether the name resolver sent us at
+	// least one update. RPCs block on this event.
 	firstResolveEvent *grpcsync.Event

-	channelzID int64 // channelz unique identification number
-	czData     *channelzData
+	// mu protects the following fields.
+	// TODO: split mu so the same mutex isn't used for everything.
+	mu              sync.RWMutex
+	resolverWrapper *ccResolverWrapper         // Initialized in Dial; cleared in Close.
+	sc              *ServiceConfig             // Latest service config received from the resolver.
+	conns           map[*addrConn]struct{}     // Set to nil on close.
+	mkp             keepalive.ClientParameters // May be updated upon receipt of a GoAway.

 	lceMu               sync.Mutex // protects lastConnectionError
 	lastConnectionError error
@@ -536,14 +535,7 @@ func (cc *ClientConn) GetState() connectivity.State {
 // Notice: This API is EXPERIMENTAL and may be changed or removed in a later
 // release.
 func (cc *ClientConn) Connect() {
-	cc.mu.Lock()
-	defer cc.mu.Unlock()
-	if cc.balancerWrapper != nil && cc.balancerWrapper.exitIdle() {
-		return
-	}
-	for ac := range cc.conns {
-		go ac.connect()
-	}
+	cc.balancerWrapper.exitIdle()
 }

 func (cc *ClientConn) scWatcher() {
@@ -623,9 +615,7 @@ func (cc *ClientConn) updateResolverState(s resolver.State, err error) error {
 		// with the new addresses.
 		cc.maybeApplyDefaultServiceConfig(nil)

-		if cc.balancerWrapper != nil {
-			cc.balancerWrapper.resolverError(err)
-		}
+		cc.balancerWrapper.resolverError(err)

 		// No addresses are valid with err set; return early.
 		cc.mu.Unlock()
@@ -653,16 +643,10 @@ func (cc *ClientConn) updateResolverState(s resolver.State, err error) error {
 			cc.applyServiceConfigAndBalancer(sc, configSelector, s.Addresses)
 		} else {
 			ret = balancer.ErrBadResolverState
-			if cc.balancerWrapper == nil {
-				var err error
-				if s.ServiceConfig.Err != nil {
-					err = status.Errorf(codes.Unavailable, "error parsing service config: %v", s.ServiceConfig.Err)
-				} else {
-					err = status.Errorf(codes.Unavailable, "illegal service config type: %T", s.ServiceConfig.Config)
-				}
-				cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{cc.sc})
-				cc.blockingpicker.updatePicker(base.NewErrPicker(err))
-				cc.csMgr.updateState(connectivity.TransientFailure)
+			if cc.sc == nil {
+				// Apply the failing LB only if we haven't received valid service config
+				// from the name resolver in the past.
+				cc.applyFailingLB(s.ServiceConfig)
 				cc.mu.Unlock()
 				return ret
 			}
@@ -670,24 +654,12 @@ func (cc *ClientConn) updateResolverState(s resolver.State, err error) error {
 	}

 	var balCfg serviceconfig.LoadBalancingConfig
-	if cc.dopts.balancerBuilder == nil && cc.sc != nil && cc.sc.lbConfig != nil {
+	if cc.sc != nil && cc.sc.lbConfig != nil {
 		balCfg = cc.sc.lbConfig.cfg
 	}
-
-	cbn := cc.curBalancerName
 	bw := cc.balancerWrapper
 	cc.mu.Unlock()
-	if cbn != grpclbName {
-		// Filter any grpclb addresses since we don't have the grpclb balancer.
-		for i := 0; i < len(s.Addresses); {
-			if s.Addresses[i].Type == resolver.GRPCLB {
-				copy(s.Addresses[i:], s.Addresses[i+1:])
-				s.Addresses = s.Addresses[:len(s.Addresses)-1]
-				continue
-			}
-			i++
-		}
-	}
+
 	uccsErr := bw.updateClientConnState(&balancer.ClientConnState{ResolverState: s, BalancerConfig: balCfg})
 	if ret == nil {
 		ret = uccsErr // prefer ErrBadResolver state since any other error is
@@ -696,56 +668,28 @@ func (cc *ClientConn) updateResolverState(s resolver.State, err error) error {
 	return ret
 }

-// switchBalancer starts the switching from current balancer to the balancer
-// with the given name.
-//
-// It will NOT send the current address list to the new balancer. If needed,
-// caller of this function should send address list to the new balancer after
-// this function returns.
+// applyFailingLB is akin to configuring an LB policy on the channel which
+// always fails RPCs. Here, an actual LB policy is not configured, but an always
+// erroring picker is configured, which returns errors with information about
+// what was invalid in the received service config. A config selector with no
+// service config is configured, and the connectivity state of the channel is
+// set to TransientFailure.
 //
 // Caller must hold cc.mu.
-func (cc *ClientConn) switchBalancer(name string) {
-	if strings.EqualFold(cc.curBalancerName, name) {
-		return
-	}
-
-	channelz.Infof(logger, cc.channelzID, "ClientConn switching balancer to %q", name)
-	if cc.dopts.balancerBuilder != nil {
-		channelz.Info(logger, cc.channelzID, "ignoring balancer switching: Balancer DialOption used instead")
-		return
-	}
-	if cc.balancerWrapper != nil {
-		// Don't hold cc.mu while closing the balancers. The balancers may call
-		// methods that require cc.mu (e.g. cc.NewSubConn()). Holding the mutex
-		// would cause a deadlock in that case.
-		cc.mu.Unlock()
-		cc.balancerWrapper.close()
-		cc.mu.Lock()
-	}
-
-	builder := balancer.Get(name)
-	if builder == nil {
-		channelz.Warningf(logger, cc.channelzID, "Channel switches to new LB policy %q due to fallback from invalid balancer name", PickFirstBalancerName)
-		channelz.Infof(logger, cc.channelzID, "failed to get balancer builder for: %v, using pick_first instead", name)
-		builder = newPickfirstBuilder()
+func (cc *ClientConn) applyFailingLB(sc *serviceconfig.ParseResult) {
+	var err error
+	if sc.Err != nil {
+		err = status.Errorf(codes.Unavailable, "error parsing service config: %v", sc.Err)
 	} else {
-		channelz.Infof(logger, cc.channelzID, "Channel switches to new LB policy %q", name)
+		err = status.Errorf(codes.Unavailable, "illegal service config type: %T", sc.Config)
 	}
-
-	cc.curBalancerName = builder.Name()
-	cc.balancerWrapper = newCCBalancerWrapper(cc, builder, cc.balancerBuildOpts)
+	cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{nil})
+	cc.blockingpicker.updatePicker(base.NewErrPicker(err))
+	cc.csMgr.updateState(connectivity.TransientFailure)
 }

 func (cc *ClientConn) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State, err error) {
-	cc.mu.Lock()
-	if cc.conns == nil {
-		cc.mu.Unlock()
-		return
-	}
-	// TODO(bar switching) send updates to all balancer wrappers when balancer
-	// gracefully switching is supported.
-	cc.balancerWrapper.handleSubConnStateChange(sc, s, err)
-	cc.mu.Unlock()
+	cc.balancerWrapper.updateSubConnState(sc, s, err)
 }

 // newAddrConn creates an addrConn for addrs and adds it to cc.conns.
@@ -768,17 +712,21 @@ func (cc *ClientConn) newAddrConn(addrs []resolver.Address, opts balancer.NewSub
 		cc.mu.Unlock()
 		return nil, ErrClientConnClosing
 	}
-	if channelz.IsOn() {
-		ac.channelzID = channelz.RegisterSubChannel(ac, cc.channelzID, "")
-		channelz.AddTraceEvent(logger, ac.channelzID, 0, &channelz.TraceEventDesc{
-			Desc:     "Subchannel Created",
-			Severity: channelz.CtInfo,
-			Parent: &channelz.TraceEventDesc{
-				Desc:     fmt.Sprintf("Subchannel(id:%d) created", ac.channelzID),
-				Severity: channelz.CtInfo,
-			},
-		})
+
+	var err error
+	ac.channelzID, err = channelz.RegisterSubChannel(ac, cc.channelzID, "")
+	if err != nil {
+		return nil, err
 	}
+	channelz.AddTraceEvent(logger, ac.channelzID, 0, &channelz.TraceEventDesc{
+		Desc:     "Subchannel created",
+		Severity: channelz.CtInfo,
+		Parent: &channelz.TraceEventDesc{
+			Desc:     fmt.Sprintf("Subchannel(id:%d) created", ac.channelzID.Int()),
+			Severity: channelz.CtInfo,
+		},
+	})
+
 	cc.conns[ac] = struct{}{}
 	cc.mu.Unlock()
 	return ac, nil
@@ -853,16 +801,31 @@ func (ac *addrConn) connect() error {
 	return nil
 }

+func equalAddresses(a, b []resolver.Address) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i, v := range a {
+		if !v.Equal(b[i]) {
+			return false
+		}
+	}
+	return true
+}
+
 // tryUpdateAddrs tries to update ac.addrs with the new addresses list.
 //
-// If ac is Connecting, it returns false. The caller should tear down the ac and
-// create a new one. Note that the backoff will be reset when this happens.
-//
 // If ac is TransientFailure, it updates ac.addrs and returns true. The updated
 // addresses will be picked up by retry in the next iteration after backoff.
 //
 // If ac is Shutdown or Idle, it updates ac.addrs and returns true.
 //
+// If the addresses is the same as the old list, it does nothing and returns
+// true.
+//
+// If ac is Connecting, it returns false. The caller should tear down the ac and
+// create a new one. Note that the backoff will be reset when this happens.
+//
 // If ac is Ready, it checks whether current connected address of ac is in the
 // new addrs list.
 //  - If true, it updates ac.addrs and returns true. The ac will keep using
@@ -879,6 +842,10 @@ func (ac *addrConn) tryUpdateAddrs(addrs []resolver.Address) bool {
 		return true
 	}

+	if equalAddresses(ac.addrs, addrs) {
+		return true
+	}
+
 	if ac.state == connectivity.Connecting {
 		return false
 	}
@@ -959,14 +926,10 @@ func (cc *ClientConn) healthCheckConfig() *healthCheckConfig {
 }

 func (cc *ClientConn) getTransport(ctx context.Context, failfast bool, method string) (transport.ClientTransport, func(balancer.DoneInfo), error) {
-	t, done, err := cc.blockingpicker.pick(ctx, failfast, balancer.PickInfo{
+	return cc.blockingpicker.pick(ctx, failfast, balancer.PickInfo{
 		Ctx:            ctx,
 		FullMethodName: method,
 	})
-	if err != nil {
-		return nil, nil, toRPCErr(err)
-	}
-	return t, done, nil
 }

 func (cc *ClientConn) applyServiceConfigAndBalancer(sc *ServiceConfig, configSelector iresolver.ConfigSelector, addrs []resolver.Address) {
@@ -991,35 +954,26 @@ func (cc *ClientConn) applyServiceConfigAndBalancer(sc *ServiceConfig, configSel
 		cc.retryThrottler.Store((*retryThrottler)(nil))
 	}

-	if cc.dopts.balancerBuilder == nil {
-		// Only look at balancer types and switch balancer if balancer dial
-		// option is not set.
-		var newBalancerName string
-		if cc.sc != nil && cc.sc.lbConfig != nil {
-			newBalancerName = cc.sc.lbConfig.name
-		} else {
-			var isGRPCLB bool
-			for _, a := range addrs {
-				if a.Type == resolver.GRPCLB {
-					isGRPCLB = true
-					break
-				}
-			}
-			if isGRPCLB {
-				newBalancerName = grpclbName
-			} else if cc.sc != nil && cc.sc.LB != nil {
-				newBalancerName = *cc.sc.LB
-			} else {
-				newBalancerName = PickFirstBalancerName
+	var newBalancerName string
+	if cc.sc != nil && cc.sc.lbConfig != nil {
+		newBalancerName = cc.sc.lbConfig.name
+	} else {
+		var isGRPCLB bool
+		for _, a := range addrs {
+			if a.Type == resolver.GRPCLB {
+				isGRPCLB = true
+				break
 			}
 		}
-		cc.switchBalancer(newBalancerName)
-	} else if cc.balancerWrapper == nil {
-		// Balancer dial option was set, and this is the first time handling
-		// resolved addresses. Build a balancer with dopts.balancerBuilder.
-		cc.curBalancerName = cc.dopts.balancerBuilder.Name()
-		cc.balancerWrapper = newCCBalancerWrapper(cc, cc.dopts.balancerBuilder, cc.balancerBuildOpts)
+		if isGRPCLB {
+			newBalancerName = grpclbName
+		} else if cc.sc != nil && cc.sc.LB != nil {
+			newBalancerName = *cc.sc.LB
+		} else {
+			newBalancerName = PickFirstBalancerName
+		}
 	}
+	cc.balancerWrapper.switchTo(newBalancerName)
 }

 func (cc *ClientConn) resolveNow(o resolver.ResolveNowOptions) {
@@ -1070,11 +1024,11 @@ func (cc *ClientConn) Close() error {
 	rWrapper := cc.resolverWrapper
 	cc.resolverWrapper = nil
 	bWrapper := cc.balancerWrapper
-	cc.balancerWrapper = nil
 	cc.mu.Unlock()

+	// The order of closing matters here since the balancer wrapper assumes the
+	// picker is closed before it is closed.
 	cc.blockingpicker.close()
-
 	if bWrapper != nil {
 		bWrapper.close()
 	}
@@ -1085,22 +1039,22 @@ func (cc *ClientConn) Close() error {
 	for ac := range conns {
 		ac.tearDown(ErrClientConnClosing)
 	}
-	if channelz.IsOn() {
-		ted := &channelz.TraceEventDesc{
-			Desc:     "Channel Deleted",
+	ted := &channelz.TraceEventDesc{
+		Desc:     "Channel deleted",
+		Severity: channelz.CtInfo,
+	}
+	if cc.dopts.channelzParentID != nil {
+		ted.Parent = &channelz.TraceEventDesc{
+			Desc:     fmt.Sprintf("Nested channel(id:%d) deleted", cc.channelzID.Int()),
 			Severity: channelz.CtInfo,
 		}
-		if cc.dopts.channelzParentID != 0 {
-			ted.Parent = &channelz.TraceEventDesc{
-				Desc:     fmt.Sprintf("Nested channel(id:%d) deleted", cc.channelzID),
-				Severity: channelz.CtInfo,
-			}
-		}
-		channelz.AddTraceEvent(logger, cc.channelzID, 0, ted)
-		// TraceEvent needs to be called before RemoveEntry, as TraceEvent may add trace reference to
-		// the entity being deleted, and thus prevent it from being deleted right away.
-		channelz.RemoveEntry(cc.channelzID)
 	}
+	channelz.AddTraceEvent(logger, cc.channelzID, 0, ted)
+	// TraceEvent needs to be called before RemoveEntry, as TraceEvent may add
+	// trace reference to the entity being deleted, and thus prevent it from being
+	// deleted right away.
+	channelz.RemoveEntry(cc.channelzID)
+
 	return nil
 }

@@ -1130,7 +1084,7 @@ type addrConn struct {
 	backoffIdx   int // Needs to be stateful for resetConnectBackoff.
 	resetBackoff chan struct{}

-	channelzID int64 // channelz unique identification number.
+	channelzID *channelz.Identifier
 	czData     *channelzData
 }

@@ -1284,6 +1238,7 @@ func (ac *addrConn) createTransport(addr resolver.Address, copts transport.Conne
 		ac.mu.Lock()
 		defer ac.mu.Unlock()
 		defer connClosed.Fire()
+		defer hcancel()
 		if !hcStarted || hctx.Err() != nil {
 			// We didn't start the health check or set the state to READY, so
 			// no need to do anything else here.
@@ -1294,7 +1249,6 @@ func (ac *addrConn) createTransport(addr resolver.Address, copts transport.Conne
 			// state, since there may be a new transport in this addrConn.
 			return
 		}
-		hcancel()
 		ac.transport = nil
 		// Refresh the name resolver
 		ac.cc.resolveNow(resolver.ResolveNowOptions{})
@@ -1312,14 +1266,13 @@ func (ac *addrConn) createTransport(addr resolver.Address, copts transport.Conne

 	connectCtx, cancel := context.WithDeadline(ac.ctx, connectDeadline)
 	defer cancel()
-	if channelz.IsOn() {
-		copts.ChannelzParentID = ac.channelzID
-	}
+	copts.ChannelzParentID = ac.channelzID

 	newTr, err := transport.NewClientTransport(connectCtx, ac.cc.ctx, addr, copts, func() { prefaceReceived.Fire() }, onGoAway, onClose)
 	if err != nil {
 		// newTr is either nil, or closed.
-		channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %v. Err: %v", addr, err)
+		hcancel()
+		channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %s. Err: %v", addr, err)
 		return err
 	}

@@ -1332,7 +1285,7 @@ func (ac *addrConn) createTransport(addr resolver.Address, copts transport.Conne
 		newTr.Close(transport.ErrConnClosing)
 		if connectCtx.Err() == context.DeadlineExceeded {
 			err := errors.New("failed to receive server preface within timeout")
-			channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %v: %v", addr, err)
+			channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %s: %v", addr, err)
 			return err
 		}
 		return nil
@@ -1497,19 +1450,18 @@ func (ac *addrConn) tearDown(err error) {
 		curTr.GracefulClose()
 		ac.mu.Lock()
 	}
-	if channelz.IsOn() {
-		channelz.AddTraceEvent(logger, ac.channelzID, 0, &channelz.TraceEventDesc{
-			Desc:     "Subchannel Deleted",
+	channelz.AddTraceEvent(logger, ac.channelzID, 0, &channelz.TraceEventDesc{
+		Desc:     "Subchannel deleted",
+		Severity: channelz.CtInfo,
+		Parent: &channelz.TraceEventDesc{
+			Desc:     fmt.Sprintf("Subchannel(id:%d) deleted", ac.channelzID.Int()),
 			Severity: channelz.CtInfo,
-			Parent: &channelz.TraceEventDesc{
-				Desc:     fmt.Sprintf("Subchanel(id:%d) deleted", ac.channelzID),
-				Severity: channelz.CtInfo,
-			},
-		})
-		// TraceEvent needs to be called before RemoveEntry, as TraceEvent may add trace reference to
-		// the entity being deleted, and thus prevent it from being deleted right away.
-		channelz.RemoveEntry(ac.channelzID)
-	}
+		},
+	})
+	// TraceEvent needs to be called before RemoveEntry, as TraceEvent may add
+	// trace reference to the entity being deleted, and thus prevent it from
+	// being deleted right away.
+	channelz.RemoveEntry(ac.channelzID)
 	ac.mu.Unlock()
 }

@@ -20,12 +20,11 @@ package grpc

 import (
 	"context"
-	"fmt"
 	"net"
 	"time"

 	"google.golang.org/grpc/backoff"
-	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/channelz"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/credentials/insecure"
 	"google.golang.org/grpc/internal"
@@ -45,19 +44,17 @@ type dialOptions struct {
 	chainUnaryInts  []UnaryClientInterceptor
 	chainStreamInts []StreamClientInterceptor

-	cp              Compressor
-	dc              Decompressor
-	bs              internalbackoff.Strategy
-	block           bool
-	returnLastError bool
-	timeout         time.Duration
-	scChan          <-chan ServiceConfig
-	authority       string
-	copts           transport.ConnectOptions
-	callOptions     []CallOption
-	// This is used by WithBalancerName dial option.
-	balancerBuilder             balancer.Builder
-	channelzParentID            int64
+	cp                          Compressor
+	dc                          Decompressor
+	bs                          internalbackoff.Strategy
+	block                       bool
+	returnLastError             bool
+	timeout                     time.Duration
+	scChan                      <-chan ServiceConfig
+	authority                   string
+	copts                       transport.ConnectOptions
+	callOptions                 []CallOption
+	channelzParentID            *channelz.Identifier
 	disableServiceConfig        bool
 	disableRetry                bool
 	disableHealthCheck          bool
@@ -195,25 +192,6 @@ func WithDecompressor(dc Decompressor) DialOption {
 	})
 }

-// WithBalancerName sets the balancer that the ClientConn will be initialized
-// with. Balancer registered with balancerName will be used. This function
-// panics if no balancer was registered by balancerName.
-//
-// The balancer cannot be overridden by balancer option specified by service
-// config.
-//
-// Deprecated: use WithDefaultServiceConfig and WithDisableServiceConfig
-// instead.  Will be removed in a future 1.x release.
-func WithBalancerName(balancerName string) DialOption {
-	builder := balancer.Get(balancerName)
-	if builder == nil {
-		panic(fmt.Sprintf("grpc.WithBalancerName: no balancer is registered for name %v", balancerName))
-	}
-	return newFuncDialOption(func(o *dialOptions) {
-		o.balancerBuilder = builder
-	})
-}
-
 // WithServiceConfig returns a DialOption which has a channel to read the
 // service configuration.
 //
@@ -304,8 +282,8 @@ func WithReturnConnectionError() DialOption {
 // WithCredentialsBundle or WithPerRPCCredentials) which require transport
 // security is incompatible and will cause grpc.Dial() to fail.
 //
-// Deprecated: use WithTransportCredentials and insecure.NewCredentials() instead.
-// Will be supported throughout 1.x.
+// Deprecated: use WithTransportCredentials and insecure.NewCredentials()
+// instead. Will be supported throughout 1.x.
 func WithInsecure() DialOption {
 	return newFuncDialOption(func(o *dialOptions) {
 		o.copts.TransportCredentials = insecure.NewCredentials()
@@ -498,7 +476,7 @@ func WithAuthority(a string) DialOption {
 //
 // Notice: This API is EXPERIMENTAL and may be changed or removed in a
 // later release.
-func WithChannelzParentID(id int64) DialOption {
+func WithChannelzParentID(id *channelz.Identifier) DialOption {
 	return newFuncDialOption(func(o *dialOptions) {
 		o.channelzParentID = id
 	})
@@ -108,7 +108,7 @@ var registeredCodecs = make(map[string]Codec)
 // more details.
 //
 // NOTE: this function must only be called during initialization time (i.e. in
-// an init() function), and is not thread-safe.  If multiple Compressors are
+// an init() function), and is not thread-safe.  If multiple Codecs are
 // registered with the same name, the one registered last will take effect.
 func RegisterCodec(codec Codec) {
 	if codec == nil {
@@ -0,0 +1,382 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package gracefulswitch implements a graceful switch load balancer.
+package gracefulswitch
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/balancer/base"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/resolver"
+)
+
+var errBalancerClosed = errors.New("gracefulSwitchBalancer is closed")
+var _ balancer.Balancer = (*Balancer)(nil)
+
+// NewBalancer returns a graceful switch Balancer.
+func NewBalancer(cc balancer.ClientConn, opts balancer.BuildOptions) *Balancer {
+	return &Balancer{
+		cc:    cc,
+		bOpts: opts,
+	}
+}
+
+// Balancer is a utility to gracefully switch from one balancer to
+// a new balancer. It implements the balancer.Balancer interface.
+type Balancer struct {
+	bOpts balancer.BuildOptions
+	cc    balancer.ClientConn
+
+	// mu protects the following fields and all fields within balancerCurrent
+	// and balancerPending. mu does not need to be held when calling into the
+	// child balancers, as all calls into these children happen only as a direct
+	// result of a call into the gracefulSwitchBalancer, which are also
+	// guaranteed to be synchronous. There is one exception: an UpdateState call
+	// from a child balancer when current and pending are populated can lead to
+	// calling Close() on the current. To prevent that racing with an
+	// UpdateSubConnState from the channel, we hold currentMu during Close and
+	// UpdateSubConnState calls.
+	mu              sync.Mutex
+	balancerCurrent *balancerWrapper
+	balancerPending *balancerWrapper
+	closed          bool // set to true when this balancer is closed
+
+	// currentMu must be locked before mu. This mutex guards against this
+	// sequence of events: UpdateSubConnState() called, finds the
+	// balancerCurrent, gives up lock, updateState comes in, causes Close() on
+	// balancerCurrent before the UpdateSubConnState is called on the
+	// balancerCurrent.
+	currentMu sync.Mutex
+}
+
+// swap swaps out the current lb with the pending lb and updates the ClientConn.
+// The caller must hold gsb.mu.
+func (gsb *Balancer) swap() {
+	gsb.cc.UpdateState(gsb.balancerPending.lastState)
+	cur := gsb.balancerCurrent
+	gsb.balancerCurrent = gsb.balancerPending
+	gsb.balancerPending = nil
+	go func() {
+		gsb.currentMu.Lock()
+		defer gsb.currentMu.Unlock()
+		cur.Close()
+	}()
+}
+
+// Helper function that checks if the balancer passed in is current or pending.
+// The caller must hold gsb.mu.
+func (gsb *Balancer) balancerCurrentOrPending(bw *balancerWrapper) bool {
+	return bw == gsb.balancerCurrent || bw == gsb.balancerPending
+}
+
+// SwitchTo initializes the graceful switch process, which completes based on
+// connectivity state changes on the current/pending balancer. Thus, the switch
+// process is not complete when this method returns. This method must be called
+// synchronously alongside the rest of the balancer.Balancer methods this
+// Graceful Switch Balancer implements.
+func (gsb *Balancer) SwitchTo(builder balancer.Builder) error {
+	gsb.mu.Lock()
+	if gsb.closed {
+		gsb.mu.Unlock()
+		return errBalancerClosed
+	}
+	bw := &balancerWrapper{
+		gsb: gsb,
+		lastState: balancer.State{
+			ConnectivityState: connectivity.Connecting,
+			Picker:            base.NewErrPicker(balancer.ErrNoSubConnAvailable),
+		},
+		subconns: make(map[balancer.SubConn]bool),
+	}
+	balToClose := gsb.balancerPending // nil if there is no pending balancer
+	if gsb.balancerCurrent == nil {
+		gsb.balancerCurrent = bw
+	} else {
+		gsb.balancerPending = bw
+	}
+	gsb.mu.Unlock()
+	balToClose.Close()
+	// This function takes a builder instead of a balancer because builder.Build
+	// can call back inline, and this utility needs to handle the callbacks.
+	newBalancer := builder.Build(bw, gsb.bOpts)
+	if newBalancer == nil {
+		// This is illegal and should never happen; we clear the balancerWrapper
+		// we were constructing if it happens to avoid a potential panic.
+		gsb.mu.Lock()
+		if gsb.balancerPending != nil {
+			gsb.balancerPending = nil
+		} else {
+			gsb.balancerCurrent = nil
+		}
+		gsb.mu.Unlock()
+		return balancer.ErrBadResolverState
+	}
+
+	// This write doesn't need to take gsb.mu because this field never gets read
+	// or written to on any calls from the current or pending. Calls from grpc
+	// to this balancer are guaranteed to be called synchronously, so this
+	// bw.Balancer field will never be forwarded to until this SwitchTo()
+	// function returns.
+	bw.Balancer = newBalancer
+	return nil
+}
+
+// Returns nil if the graceful switch balancer is closed.
+func (gsb *Balancer) latestBalancer() *balancerWrapper {
+	gsb.mu.Lock()
+	defer gsb.mu.Unlock()
+	if gsb.balancerPending != nil {
+		return gsb.balancerPending
+	}
+	return gsb.balancerCurrent
+}
+
+// UpdateClientConnState forwards the update to the latest balancer created.
+func (gsb *Balancer) UpdateClientConnState(state balancer.ClientConnState) error {
+	// The resolver data is only relevant to the most recent LB Policy.
+	balToUpdate := gsb.latestBalancer()
+	if balToUpdate == nil {
+		return errBalancerClosed
+	}
+	// Perform this call without gsb.mu to prevent deadlocks if the child calls
+	// back into the channel. The latest balancer can never be closed during a
+	// call from the channel, even without gsb.mu held.
+	return balToUpdate.UpdateClientConnState(state)
+}
+
+// ResolverError forwards the error to the latest balancer created.
+func (gsb *Balancer) ResolverError(err error) {
+	// The resolver data is only relevant to the most recent LB Policy.
+	balToUpdate := gsb.latestBalancer()
+	if balToUpdate == nil {
+		return
+	}
+	// Perform this call without gsb.mu to prevent deadlocks if the child calls
+	// back into the channel. The latest balancer can never be closed during a
+	// call from the channel, even without gsb.mu held.
+	balToUpdate.ResolverError(err)
+}
+
+// ExitIdle forwards the call to the latest balancer created.
+//
+// If the latest balancer does not support ExitIdle, the subConns are
+// re-connected to manually.
+func (gsb *Balancer) ExitIdle() {
+	balToUpdate := gsb.latestBalancer()
+	if balToUpdate == nil {
+		return
+	}
+	// There is no need to protect this read with a mutex, as the write to the
+	// Balancer field happens in SwitchTo, which completes before this can be
+	// called.
+	if ei, ok := balToUpdate.Balancer.(balancer.ExitIdler); ok {
+		ei.ExitIdle()
+		return
+	}
+	for sc := range balToUpdate.subconns {
+		sc.Connect()
+	}
+}
+
+// UpdateSubConnState forwards the update to the appropriate child.
+func (gsb *Balancer) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState) {
+	gsb.currentMu.Lock()
+	defer gsb.currentMu.Unlock()
+	gsb.mu.Lock()
+	// Forward update to the appropriate child.  Even if there is a pending
+	// balancer, the current balancer should continue to get SubConn updates to
+	// maintain the proper state while the pending is still connecting.
+	var balToUpdate *balancerWrapper
+	if gsb.balancerCurrent != nil && gsb.balancerCurrent.subconns[sc] {
+		balToUpdate = gsb.balancerCurrent
+	} else if gsb.balancerPending != nil && gsb.balancerPending.subconns[sc] {
+		balToUpdate = gsb.balancerPending
+	}
+	gsb.mu.Unlock()
+	if balToUpdate == nil {
+		// SubConn belonged to a stale lb policy that has not yet fully closed,
+		// or the balancer was already closed.
+		return
+	}
+	balToUpdate.UpdateSubConnState(sc, state)
+}
+
+// Close closes any active child balancers.
+func (gsb *Balancer) Close() {
+	gsb.mu.Lock()
+	gsb.closed = true
+	currentBalancerToClose := gsb.balancerCurrent
+	gsb.balancerCurrent = nil
+	pendingBalancerToClose := gsb.balancerPending
+	gsb.balancerPending = nil
+	gsb.mu.Unlock()
+
+	currentBalancerToClose.Close()
+	pendingBalancerToClose.Close()
+}
+
+// balancerWrapper wraps a balancer.Balancer, and overrides some Balancer
+// methods to help cleanup SubConns created by the wrapped balancer.
+//
+// It implements the balancer.ClientConn interface and is passed down in that
+// capacity to the wrapped balancer. It maintains a set of subConns created by
+// the wrapped balancer and calls from the latter to create/update/remove
+// SubConns update this set before being forwarded to the parent ClientConn.
+// State updates from the wrapped balancer can result in invocation of the
+// graceful switch logic.
+type balancerWrapper struct {
+	balancer.Balancer
+	gsb *Balancer
+
+	lastState balancer.State
+	subconns  map[balancer.SubConn]bool // subconns created by this balancer
+}
+
+func (bw *balancerWrapper) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState) {
+	if state.ConnectivityState == connectivity.Shutdown {
+		bw.gsb.mu.Lock()
+		delete(bw.subconns, sc)
+		bw.gsb.mu.Unlock()
+	}
+	// There is no need to protect this read with a mutex, as the write to the
+	// Balancer field happens in SwitchTo, which completes before this can be
+	// called.
+	bw.Balancer.UpdateSubConnState(sc, state)
+}
+
+// Close closes the underlying LB policy and removes the subconns it created. bw
+// must not be referenced via balancerCurrent or balancerPending in gsb when
+// called. gsb.mu must not be held.  Does not panic with a nil receiver.
+func (bw *balancerWrapper) Close() {
+	// before Close is called.
+	if bw == nil {
+		return
+	}
+	// There is no need to protect this read with a mutex, as Close() is
+	// impossible to be called concurrently with the write in SwitchTo(). The
+	// callsites of Close() for this balancer in Graceful Switch Balancer will
+	// never be called until SwitchTo() returns.
+	bw.Balancer.Close()
+	bw.gsb.mu.Lock()
+	for sc := range bw.subconns {
+		bw.gsb.cc.RemoveSubConn(sc)
+	}
+	bw.gsb.mu.Unlock()
+}
+
+func (bw *balancerWrapper) UpdateState(state balancer.State) {
+	// Hold the mutex for this entire call to ensure it cannot occur
+	// concurrently with other updateState() calls. This causes updates to
+	// lastState and calls to cc.UpdateState to happen atomically.
+	bw.gsb.mu.Lock()
+	defer bw.gsb.mu.Unlock()
+	bw.lastState = state
+
+	if !bw.gsb.balancerCurrentOrPending(bw) {
+		return
+	}
+
+	if bw == bw.gsb.balancerCurrent {
+		// In the case that the current balancer exits READY, and there is a pending
+		// balancer, you can forward the pending balancer's cached State up to
+		// ClientConn and swap the pending into the current. This is because there
+		// is no reason to gracefully switch from and keep using the old policy as
+		// the ClientConn is not connected to any backends.
+		if state.ConnectivityState != connectivity.Ready && bw.gsb.balancerPending != nil {
+			bw.gsb.swap()
+			return
+		}
+		// Even if there is a pending balancer waiting to be gracefully switched to,
+		// continue to forward current balancer updates to the Client Conn. Ignoring
+		// state + picker from the current would cause undefined behavior/cause the
+		// system to behave incorrectly from the current LB policies perspective.
+		// Also, the current LB is still being used by grpc to choose SubConns per
+		// RPC, and thus should use the most updated form of the current balancer.
+		bw.gsb.cc.UpdateState(state)
+		return
+	}
+	// This method is now dealing with a state update from the pending balancer.
+	// If the current balancer is currently in a state other than READY, the new
+	// policy can be swapped into place immediately. This is because there is no
+	// reason to gracefully switch from and keep using the old policy as the
+	// ClientConn is not connected to any backends.
+	if state.ConnectivityState != connectivity.Connecting || bw.gsb.balancerCurrent.lastState.ConnectivityState != connectivity.Ready {
+		bw.gsb.swap()
+	}
+}
+
+func (bw *balancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) {
+	bw.gsb.mu.Lock()
+	if !bw.gsb.balancerCurrentOrPending(bw) {
+		bw.gsb.mu.Unlock()
+		return nil, fmt.Errorf("%T at address %p that called NewSubConn is deleted", bw, bw)
+	}
+	bw.gsb.mu.Unlock()
+
+	sc, err := bw.gsb.cc.NewSubConn(addrs, opts)
+	if err != nil {
+		return nil, err
+	}
+	bw.gsb.mu.Lock()
+	if !bw.gsb.balancerCurrentOrPending(bw) { // balancer was closed during this call
+		bw.gsb.cc.RemoveSubConn(sc)
+		bw.gsb.mu.Unlock()
+		return nil, fmt.Errorf("%T at address %p that called NewSubConn is deleted", bw, bw)
+	}
+	bw.subconns[sc] = true
+	bw.gsb.mu.Unlock()
+	return sc, nil
+}
+
+func (bw *balancerWrapper) ResolveNow(opts resolver.ResolveNowOptions) {
+	// Ignore ResolveNow requests from anything other than the most recent
+	// balancer, because older balancers were already removed from the config.
+	if bw != bw.gsb.latestBalancer() {
+		return
+	}
+	bw.gsb.cc.ResolveNow(opts)
+}
+
+func (bw *balancerWrapper) RemoveSubConn(sc balancer.SubConn) {
+	bw.gsb.mu.Lock()
+	if !bw.gsb.balancerCurrentOrPending(bw) {
+		bw.gsb.mu.Unlock()
+		return
+	}
+	bw.gsb.mu.Unlock()
+	bw.gsb.cc.RemoveSubConn(sc)
+}
+
+func (bw *balancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resolver.Address) {
+	bw.gsb.mu.Lock()
+	if !bw.gsb.balancerCurrentOrPending(bw) {
+		bw.gsb.mu.Unlock()
+		return
+	}
+	bw.gsb.mu.Unlock()
+	bw.gsb.cc.UpdateAddresses(sc, addrs)
+}
+
+func (bw *balancerWrapper) Target() string {
+	return bw.gsb.cc.Target()
+}
@@ -31,7 +31,7 @@ import (
 // Logger is the global binary logger. It can be used to get binary logger for
 // each method.
 type Logger interface {
-	getMethodLogger(methodName string) *MethodLogger
+	GetMethodLogger(methodName string) MethodLogger
 }

 // binLogger is the global binary logger for the binary. One of this should be
@@ -49,17 +49,24 @@ func SetLogger(l Logger) {
 	binLogger = l
 }

+// GetLogger gets the binarg logger.
+//
+// Only call this at init time.
+func GetLogger() Logger {
+	return binLogger
+}
+
 // GetMethodLogger returns the methodLogger for the given methodName.
 //
 // methodName should be in the format of "/service/method".
 //
 // Each methodLogger returned by this method is a new instance. This is to
 // generate sequence id within the call.
-func GetMethodLogger(methodName string) *MethodLogger {
+func GetMethodLogger(methodName string) MethodLogger {
 	if binLogger == nil {
 		return nil
 	}
-	return binLogger.getMethodLogger(methodName)
+	return binLogger.GetMethodLogger(methodName)
 }

 func init() {
@@ -68,17 +75,29 @@ func init() {
 	binLogger = NewLoggerFromConfigString(configStr)
 }

-type methodLoggerConfig struct {
+// MethodLoggerConfig contains the setting for logging behavior of a method
+// logger. Currently, it contains the max length of header and message.
+type MethodLoggerConfig struct {
 	// Max length of header and message.
-	hdr, msg uint64
+	Header, Message uint64
+}
+
+// LoggerConfig contains the config for loggers to create method loggers.
+type LoggerConfig struct {
+	All      *MethodLoggerConfig
+	Services map[string]*MethodLoggerConfig
+	Methods  map[string]*MethodLoggerConfig
+
+	Blacklist map[string]struct{}
 }

 type logger struct {
-	all      *methodLoggerConfig
-	services map[string]*methodLoggerConfig
-	methods  map[string]*methodLoggerConfig
+	config LoggerConfig
+}

-	blacklist map[string]struct{}
+// NewLoggerFromConfig builds a logger with the given LoggerConfig.
+func NewLoggerFromConfig(config LoggerConfig) Logger {
+	return &logger{config: config}
 }

 // newEmptyLogger creates an empty logger. The map fields need to be filled in
@@ -88,57 +107,57 @@ func newEmptyLogger() *logger {
 }

 // Set method logger for "*".
-func (l *logger) setDefaultMethodLogger(ml *methodLoggerConfig) error {
-	if l.all != nil {
+func (l *logger) setDefaultMethodLogger(ml *MethodLoggerConfig) error {
+	if l.config.All != nil {
 		return fmt.Errorf("conflicting global rules found")
 	}
-	l.all = ml
+	l.config.All = ml
 	return nil
 }

 // Set method logger for "service/*".
 //
 // New methodLogger with same service overrides the old one.
-func (l *logger) setServiceMethodLogger(service string, ml *methodLoggerConfig) error {
-	if _, ok := l.services[service]; ok {
+func (l *logger) setServiceMethodLogger(service string, ml *MethodLoggerConfig) error {
+	if _, ok := l.config.Services[service]; ok {
 		return fmt.Errorf("conflicting service rules for service %v found", service)
 	}
-	if l.services == nil {
-		l.services = make(map[string]*methodLoggerConfig)
+	if l.config.Services == nil {
+		l.config.Services = make(map[string]*MethodLoggerConfig)
 	}
-	l.services[service] = ml
+	l.config.Services[service] = ml
 	return nil
 }

 // Set method logger for "service/method".
 //
 // New methodLogger with same method overrides the old one.
-func (l *logger) setMethodMethodLogger(method string, ml *methodLoggerConfig) error {
-	if _, ok := l.blacklist[method]; ok {
+func (l *logger) setMethodMethodLogger(method string, ml *MethodLoggerConfig) error {
+	if _, ok := l.config.Blacklist[method]; ok {
 		return fmt.Errorf("conflicting blacklist rules for method %v found", method)
 	}
-	if _, ok := l.methods[method]; ok {
+	if _, ok := l.config.Methods[method]; ok {
 		return fmt.Errorf("conflicting method rules for method %v found", method)
 	}
-	if l.methods == nil {
-		l.methods = make(map[string]*methodLoggerConfig)
+	if l.config.Methods == nil {
+		l.config.Methods = make(map[string]*MethodLoggerConfig)
 	}
-	l.methods[method] = ml
+	l.config.Methods[method] = ml
 	return nil
 }

 // Set blacklist method for "-service/method".
 func (l *logger) setBlacklist(method string) error {
-	if _, ok := l.blacklist[method]; ok {
+	if _, ok := l.config.Blacklist[method]; ok {
 		return fmt.Errorf("conflicting blacklist rules for method %v found", method)
 	}
-	if _, ok := l.methods[method]; ok {
+	if _, ok := l.config.Methods[method]; ok {
 		return fmt.Errorf("conflicting method rules for method %v found", method)
 	}
-	if l.blacklist == nil {
-		l.blacklist = make(map[string]struct{})
+	if l.config.Blacklist == nil {
+		l.config.Blacklist = make(map[string]struct{})
 	}
-	l.blacklist[method] = struct{}{}
+	l.config.Blacklist[method] = struct{}{}
 	return nil
 }

@@ -148,23 +167,23 @@ func (l *logger) setBlacklist(method string) error {
 //
 // Each methodLogger returned by this method is a new instance. This is to
 // generate sequence id within the call.
-func (l *logger) getMethodLogger(methodName string) *MethodLogger {
+func (l *logger) GetMethodLogger(methodName string) MethodLogger {
 	s, m, err := grpcutil.ParseMethod(methodName)
 	if err != nil {
 		grpclogLogger.Infof("binarylogging: failed to parse %q: %v", methodName, err)
 		return nil
 	}
-	if ml, ok := l.methods[s+"/"+m]; ok {
-		return newMethodLogger(ml.hdr, ml.msg)
+	if ml, ok := l.config.Methods[s+"/"+m]; ok {
+		return newMethodLogger(ml.Header, ml.Message)
 	}
-	if _, ok := l.blacklist[s+"/"+m]; ok {
+	if _, ok := l.config.Blacklist[s+"/"+m]; ok {
 		return nil
 	}
-	if ml, ok := l.services[s]; ok {
-		return newMethodLogger(ml.hdr, ml.msg)
+	if ml, ok := l.config.Services[s]; ok {
+		return newMethodLogger(ml.Header, ml.Message)
 	}
-	if l.all == nil {
+	if l.config.All == nil {
 		return nil
 	}
-	return newMethodLogger(l.all.hdr, l.all.msg)
+	return newMethodLogger(l.config.All.Header, l.config.All.Message)
 }
@@ -89,7 +89,7 @@ func (l *logger) fillMethodLoggerWithConfigString(config string) error {
 		if err != nil {
 			return fmt.Errorf("invalid config: %q, %v", config, err)
 		}
-		if err := l.setDefaultMethodLogger(&methodLoggerConfig{hdr: hdr, msg: msg}); err != nil {
+		if err := l.setDefaultMethodLogger(&MethodLoggerConfig{Header: hdr, Message: msg}); err != nil {
 			return fmt.Errorf("invalid config: %v", err)
 		}
 		return nil
@@ -104,11 +104,11 @@ func (l *logger) fillMethodLoggerWithConfigString(config string) error {
 		return fmt.Errorf("invalid header/message length config: %q, %v", suffix, err)
 	}
 	if m == "*" {
-		if err := l.setServiceMethodLogger(s, &methodLoggerConfig{hdr: hdr, msg: msg}); err != nil {
+		if err := l.setServiceMethodLogger(s, &MethodLoggerConfig{Header: hdr, Message: msg}); err != nil {
 			return fmt.Errorf("invalid config: %v", err)
 		}
 	} else {
-		if err := l.setMethodMethodLogger(s+"/"+m, &methodLoggerConfig{hdr: hdr, msg: msg}); err != nil {
+		if err := l.setMethodMethodLogger(s+"/"+m, &MethodLoggerConfig{Header: hdr, Message: msg}); err != nil {
 			return fmt.Errorf("invalid config: %v", err)
 		}
 	}
@@ -48,7 +48,11 @@ func (g *callIDGenerator) reset() {
 var idGen callIDGenerator

 // MethodLogger is the sub-logger for each method.
-type MethodLogger struct {
+type MethodLogger interface {
+	Log(LogEntryConfig)
+}
+
+type methodLogger struct {
 	headerMaxLen, messageMaxLen uint64

 	callID          uint64
@@ -57,8 +61,8 @@ type MethodLogger struct {
 	sink Sink // TODO(blog): make this plugable.
 }

-func newMethodLogger(h, m uint64) *MethodLogger {
-	return &MethodLogger{
+func newMethodLogger(h, m uint64) *methodLogger {
+	return &methodLogger{
 		headerMaxLen:  h,
 		messageMaxLen: m,

@@ -69,8 +73,10 @@ func newMethodLogger(h, m uint64) *MethodLogger {
 	}
 }

-// Log creates a proto binary log entry, and logs it to the sink.
-func (ml *MethodLogger) Log(c LogEntryConfig) {
+// Build is an internal only method for building the proto message out of the
+// input event. It's made public to enable other library to reuse as much logic
+// in methodLogger as possible.
+func (ml *methodLogger) Build(c LogEntryConfig) *pb.GrpcLogEntry {
 	m := c.toProto()
 	timestamp, _ := ptypes.TimestampProto(time.Now())
 	m.Timestamp = timestamp
@@ -85,11 +91,15 @@ func (ml *MethodLogger) Log(c LogEntryConfig) {
 	case *pb.GrpcLogEntry_Message:
 		m.PayloadTruncated = ml.truncateMessage(pay.Message)
 	}
-
-	ml.sink.Write(m)
+	return m
 }

-func (ml *MethodLogger) truncateMetadata(mdPb *pb.Metadata) (truncated bool) {
+// Log creates a proto binary log entry, and logs it to the sink.
+func (ml *methodLogger) Log(c LogEntryConfig) {
+	ml.sink.Write(ml.Build(c))
+}
+
+func (ml *methodLogger) truncateMetadata(mdPb *pb.Metadata) (truncated bool) {
 	if ml.headerMaxLen == maxUInt {
 		return false
 	}
@@ -119,7 +129,7 @@ func (ml *MethodLogger) truncateMetadata(mdPb *pb.Metadata) (truncated bool) {
 	return truncated
 }

-func (ml *MethodLogger) truncateMessage(msgPb *pb.Message) (truncated bool) {
+func (ml *methodLogger) truncateMessage(msgPb *pb.Message) (truncated bool) {
 	if ml.messageMaxLen == maxUInt {
 		return false
 	}
@@ -25,6 +25,7 @@ package channelz

 import (
 	"context"
+	"errors"
 	"fmt"
 	"sort"
 	"sync"
@@ -184,54 +185,77 @@ func GetServer(id int64) *ServerMetric {
 	return db.get().GetServer(id)
 }

-// RegisterChannel registers the given channel c in channelz database with ref
-// as its reference name, and add it to the child list of its parent (identified
-// by pid). pid = 0 means no parent. It returns the unique channelz tracking id
-// assigned to this channel.
-func RegisterChannel(c Channel, pid int64, ref string) int64 {
+// RegisterChannel registers the given channel c in the channelz database with
+// ref as its reference name, and adds it to the child list of its parent
+// (identified by pid). pid == nil means no parent.
+//
+// Returns a unique channelz identifier assigned to this channel.
+//
+// If channelz is not turned ON, the channelz database is not mutated.
+func RegisterChannel(c Channel, pid *Identifier, ref string) *Identifier {
 	id := idGen.genID()
+	var parent int64
+	isTopChannel := true
+	if pid != nil {
+		isTopChannel = false
+		parent = pid.Int()
+	}
+
+	if !IsOn() {
+		return newIdentifer(RefChannel, id, pid)
+	}
+
 	cn := &channel{
 		refName:     ref,
 		c:           c,
 		subChans:    make(map[int64]string),
 		nestedChans: make(map[int64]string),
 		id:          id,
-		pid:         pid,
+		pid:         parent,
 		trace:       &channelTrace{createdTime: time.Now(), events: make([]*TraceEvent, 0, getMaxTraceEntry())},
 	}
-	if pid == 0 {
-		db.get().addChannel(id, cn, true, pid)
-	} else {
-		db.get().addChannel(id, cn, false, pid)
-	}
-	return id
+	db.get().addChannel(id, cn, isTopChannel, parent)
+	return newIdentifer(RefChannel, id, pid)
 }

-// RegisterSubChannel registers the given channel c in channelz database with ref
-// as its reference name, and add it to the child list of its parent (identified
-// by pid). It returns the unique channelz tracking id assigned to this subchannel.
-func RegisterSubChannel(c Channel, pid int64, ref string) int64 {
-	if pid == 0 {
-		logger.Error("a SubChannel's parent id cannot be 0")
-		return 0
+// RegisterSubChannel registers the given subChannel c in the channelz database
+// with ref as its reference name, and adds it to the child list of its parent
+// (identified by pid).
+//
+// Returns a unique channelz identifier assigned to this subChannel.
+//
+// If channelz is not turned ON, the channelz database is not mutated.
+func RegisterSubChannel(c Channel, pid *Identifier, ref string) (*Identifier, error) {
+	if pid == nil {
+		return nil, errors.New("a SubChannel's parent id cannot be nil")
 	}
 	id := idGen.genID()
+	if !IsOn() {
+		return newIdentifer(RefSubChannel, id, pid), nil
+	}
+
 	sc := &subChannel{
 		refName: ref,
 		c:       c,
 		sockets: make(map[int64]string),
 		id:      id,
-		pid:     pid,
+		pid:     pid.Int(),
 		trace:   &channelTrace{createdTime: time.Now(), events: make([]*TraceEvent, 0, getMaxTraceEntry())},
 	}
-	db.get().addSubChannel(id, sc, pid)
-	return id
+	db.get().addSubChannel(id, sc, pid.Int())
+	return newIdentifer(RefSubChannel, id, pid), nil
 }

 // RegisterServer registers the given server s in channelz database. It returns
 // the unique channelz tracking id assigned to this server.
-func RegisterServer(s Server, ref string) int64 {
+//
+// If channelz is not turned ON, the channelz database is not mutated.
+func RegisterServer(s Server, ref string) *Identifier {
 	id := idGen.genID()
+	if !IsOn() {
+		return newIdentifer(RefServer, id, nil)
+	}
+
 	svr := &server{
 		refName:       ref,
 		s:             s,
@@ -240,71 +264,92 @@ func RegisterServer(s Server, ref string) int64 {
 		id:            id,
 	}
 	db.get().addServer(id, svr)
-	return id
+	return newIdentifer(RefServer, id, nil)
 }

 // RegisterListenSocket registers the given listen socket s in channelz database
 // with ref as its reference name, and add it to the child list of its parent
 // (identified by pid). It returns the unique channelz tracking id assigned to
 // this listen socket.
-func RegisterListenSocket(s Socket, pid int64, ref string) int64 {
-	if pid == 0 {
-		logger.Error("a ListenSocket's parent id cannot be 0")
-		return 0
+//
+// If channelz is not turned ON, the channelz database is not mutated.
+func RegisterListenSocket(s Socket, pid *Identifier, ref string) (*Identifier, error) {
+	if pid == nil {
+		return nil, errors.New("a ListenSocket's parent id cannot be 0")
 	}
 	id := idGen.genID()
-	ls := &listenSocket{refName: ref, s: s, id: id, pid: pid}
-	db.get().addListenSocket(id, ls, pid)
-	return id
+	if !IsOn() {
+		return newIdentifer(RefListenSocket, id, pid), nil
+	}
+
+	ls := &listenSocket{refName: ref, s: s, id: id, pid: pid.Int()}
+	db.get().addListenSocket(id, ls, pid.Int())
+	return newIdentifer(RefListenSocket, id, pid), nil
 }

 // RegisterNormalSocket registers the given normal socket s in channelz database
-// with ref as its reference name, and add it to the child list of its parent
+// with ref as its reference name, and adds it to the child list of its parent
 // (identified by pid). It returns the unique channelz tracking id assigned to
 // this normal socket.
-func RegisterNormalSocket(s Socket, pid int64, ref string) int64 {
-	if pid == 0 {
-		logger.Error("a NormalSocket's parent id cannot be 0")
-		return 0
+//
+// If channelz is not turned ON, the channelz database is not mutated.
+func RegisterNormalSocket(s Socket, pid *Identifier, ref string) (*Identifier, error) {
+	if pid == nil {
+		return nil, errors.New("a NormalSocket's parent id cannot be 0")
 	}
 	id := idGen.genID()
-	ns := &normalSocket{refName: ref, s: s, id: id, pid: pid}
-	db.get().addNormalSocket(id, ns, pid)
-	return id
+	if !IsOn() {
+		return newIdentifer(RefNormalSocket, id, pid), nil
+	}
+
+	ns := &normalSocket{refName: ref, s: s, id: id, pid: pid.Int()}
+	db.get().addNormalSocket(id, ns, pid.Int())
+	return newIdentifer(RefNormalSocket, id, pid), nil
 }

 // RemoveEntry removes an entry with unique channelz tracking id to be id from
 // channelz database.
-func RemoveEntry(id int64) {
-	db.get().removeEntry(id)
+//
+// If channelz is not turned ON, this function is a no-op.
+func RemoveEntry(id *Identifier) {
+	if !IsOn() {
+		return
+	}
+	db.get().removeEntry(id.Int())
 }

-// TraceEventDesc is what the caller of AddTraceEvent should provide to describe the event to be added
-// to the channel trace.
-// The Parent field is optional. It is used for event that will be recorded in the entity's parent
-// trace also.
+// TraceEventDesc is what the caller of AddTraceEvent should provide to describe
+// the event to be added to the channel trace.
+//
+// The Parent field is optional. It is used for an event that will be recorded
+// in the entity's parent trace.
 type TraceEventDesc struct {
 	Desc     string
 	Severity Severity
 	Parent   *TraceEventDesc
 }

-// AddTraceEvent adds trace related to the entity with specified id, using the provided TraceEventDesc.
-func AddTraceEvent(l grpclog.DepthLoggerV2, id int64, depth int, desc *TraceEventDesc) {
-	for d := desc; d != nil; d = d.Parent {
-		switch d.Severity {
-		case CtUnknown, CtInfo:
-			l.InfoDepth(depth+1, d.Desc)
-		case CtWarning:
-			l.WarningDepth(depth+1, d.Desc)
-		case CtError:
-			l.ErrorDepth(depth+1, d.Desc)
-		}
+// AddTraceEvent adds trace related to the entity with specified id, using the
+// provided TraceEventDesc.
+//
+// If channelz is not turned ON, this will simply log the event descriptions.
+func AddTraceEvent(l grpclog.DepthLoggerV2, id *Identifier, depth int, desc *TraceEventDesc) {
+	// Log only the trace description associated with the bottom most entity.
+	switch desc.Severity {
+	case CtUnknown, CtInfo:
+		l.InfoDepth(depth+1, withParens(id)+desc.Desc)
+	case CtWarning:
+		l.WarningDepth(depth+1, withParens(id)+desc.Desc)
+	case CtError:
+		l.ErrorDepth(depth+1, withParens(id)+desc.Desc)
 	}
+
 	if getMaxTraceEntry() == 0 {
 		return
 	}
-	db.get().traceEvent(id, desc)
+	if IsOn() {
+		db.get().traceEvent(id.Int(), desc)
+	}
 }

 // channelMap is the storage data structure for channelz.
@@ -0,0 +1,75 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package channelz
+
+import "fmt"
+
+// Identifier is an opaque identifier which uniquely identifies an entity in the
+// channelz database.
+type Identifier struct {
+	typ RefChannelType
+	id  int64
+	str string
+	pid *Identifier
+}
+
+// Type returns the entity type corresponding to id.
+func (id *Identifier) Type() RefChannelType {
+	return id.typ
+}
+
+// Int returns the integer identifier corresponding to id.
+func (id *Identifier) Int() int64 {
+	return id.id
+}
+
+// String returns a string representation of the entity corresponding to id.
+//
+// This includes some information about the parent as well. Examples:
+// Top-level channel: [Channel #channel-number]
+// Nested channel:    [Channel #parent-channel-number Channel #channel-number]
+// Sub channel:       [Channel #parent-channel SubChannel #subchannel-number]
+func (id *Identifier) String() string {
+	return id.str
+}
+
+// Equal returns true if other is the same as id.
+func (id *Identifier) Equal(other *Identifier) bool {
+	if (id != nil) != (other != nil) {
+		return false
+	}
+	if id == nil && other == nil {
+		return true
+	}
+	return id.typ == other.typ && id.id == other.id && id.pid == other.pid
+}
+
+// NewIdentifierForTesting returns a new opaque identifier to be used only for
+// testing purposes.
+func NewIdentifierForTesting(typ RefChannelType, id int64, pid *Identifier) *Identifier {
+	return newIdentifer(typ, id, pid)
+}
+
+func newIdentifer(typ RefChannelType, id int64, pid *Identifier) *Identifier {
+	str := fmt.Sprintf("%s #%d", typ, id)
+	if pid != nil {
+		str = fmt.Sprintf("%s %s", pid, str)
+	}
+	return &Identifier{typ: typ, id: id, str: str, pid: pid}
+}
@@ -26,77 +26,54 @@ import (

 var logger = grpclog.Component("channelz")

+func withParens(id *Identifier) string {
+	return "[" + id.String() + "] "
+}
+
 // Info logs and adds a trace event if channelz is on.
-func Info(l grpclog.DepthLoggerV2, id int64, args ...interface{}) {
-	if IsOn() {
-		AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     fmt.Sprint(args...),
-			Severity: CtInfo,
-		})
-	} else {
-		l.InfoDepth(1, args...)
-	}
+func Info(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
+	AddTraceEvent(l, id, 1, &TraceEventDesc{
+		Desc:     fmt.Sprint(args...),
+		Severity: CtInfo,
+	})
 }

 // Infof logs and adds a trace event if channelz is on.
-func Infof(l grpclog.DepthLoggerV2, id int64, format string, args ...interface{}) {
-	msg := fmt.Sprintf(format, args...)
-	if IsOn() {
-		AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     msg,
-			Severity: CtInfo,
-		})
-	} else {
-		l.InfoDepth(1, msg)
-	}
+func Infof(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
+	AddTraceEvent(l, id, 1, &TraceEventDesc{
+		Desc:     fmt.Sprintf(format, args...),
+		Severity: CtInfo,
+	})
 }

 // Warning logs and adds a trace event if channelz is on.
-func Warning(l grpclog.DepthLoggerV2, id int64, args ...interface{}) {
-	if IsOn() {
-		AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     fmt.Sprint(args...),
-			Severity: CtWarning,
-		})
-	} else {
-		l.WarningDepth(1, args...)
-	}
+func Warning(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
+	AddTraceEvent(l, id, 1, &TraceEventDesc{
+		Desc:     fmt.Sprint(args...),
+		Severity: CtWarning,
+	})
 }

 // Warningf logs and adds a trace event if channelz is on.
-func Warningf(l grpclog.DepthLoggerV2, id int64, format string, args ...interface{}) {
-	msg := fmt.Sprintf(format, args...)
-	if IsOn() {
-		AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     msg,
-			Severity: CtWarning,
-		})
-	} else {
-		l.WarningDepth(1, msg)
-	}
+func Warningf(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
+	AddTraceEvent(l, id, 1, &TraceEventDesc{
+		Desc:     fmt.Sprintf(format, args...),
+		Severity: CtWarning,
+	})
 }

 // Error logs and adds a trace event if channelz is on.
-func Error(l grpclog.DepthLoggerV2, id int64, args ...interface{}) {
-	if IsOn() {
-		AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     fmt.Sprint(args...),
-			Severity: CtError,
-		})
-	} else {
-		l.ErrorDepth(1, args...)
-	}
+func Error(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
+	AddTraceEvent(l, id, 1, &TraceEventDesc{
+		Desc:     fmt.Sprint(args...),
+		Severity: CtError,
+	})
 }

 // Errorf logs and adds a trace event if channelz is on.
-func Errorf(l grpclog.DepthLoggerV2, id int64, format string, args ...interface{}) {
-	msg := fmt.Sprintf(format, args...)
-	if IsOn() {
-		AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     msg,
-			Severity: CtError,
-		})
-	} else {
-		l.ErrorDepth(1, msg)
-	}
+func Errorf(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
+	AddTraceEvent(l, id, 1, &TraceEventDesc{
+		Desc:     fmt.Sprintf(format, args...),
+		Severity: CtError,
+	})
 }
@@ -686,12 +686,33 @@ const (
 type RefChannelType int

 const (
+	// RefUnknown indicates an unknown entity type, the zero value for this type.
+	RefUnknown RefChannelType = iota
 	// RefChannel indicates the referenced entity is a Channel.
-	RefChannel RefChannelType = iota
+	RefChannel
 	// RefSubChannel indicates the referenced entity is a SubChannel.
 	RefSubChannel
+	// RefServer indicates the referenced entity is a Server.
+	RefServer
+	// RefListenSocket indicates the referenced entity is a ListenSocket.
+	RefListenSocket
+	// RefNormalSocket indicates the referenced entity is a NormalSocket.
+	RefNormalSocket
 )

+var refChannelTypeToString = map[RefChannelType]string{
+	RefUnknown:      "Unknown",
+	RefChannel:      "Channel",
+	RefSubChannel:   "SubChannel",
+	RefServer:       "Server",
+	RefListenSocket: "ListenSocket",
+	RefNormalSocket: "NormalSocket",
+}
+
+func (r RefChannelType) String() string {
+	return refChannelTypeToString[r]
+}
+
 func (c *channelTrace) dumpData() *ChannelTrace {
 	c.mu.Lock()
 	ct := &ChannelTrace{EventNum: c.eventCount, CreationTime: c.createdTime}
@@ -85,3 +85,9 @@ const (
 	// that supports backend returned by grpclb balancer.
 	CredsBundleModeBackendFromBalancer = "backend-from-balancer"
 )
+
+// RLSLoadBalancingPolicyName is the name of the RLS LB policy.
+//
+// It currently has an experimental suffix which would be removed once
+// end-to-end testing of the policy is completed.
+const RLSLoadBalancingPolicyName = "rls_experimental"
@@ -22,6 +22,9 @@
 package metadata

 import (
+	"fmt"
+	"strings"
+
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/resolver"
 )
@@ -72,3 +75,46 @@ func Set(addr resolver.Address, md metadata.MD) resolver.Address {
 	addr.Attributes = addr.Attributes.WithValue(mdKey, mdValue(md))
 	return addr
 }
+
+// Validate returns an error if the input md contains invalid keys or values.
+//
+// If the header is not a pseudo-header, the following items are checked:
+// - header names must contain one or more characters from this set [0-9 a-z _ - .].
+// - if the header-name ends with a "-bin" suffix, no validation of the header value is performed.
+// - otherwise, the header value must contain one or more characters from the set [%x20-%x7E].
+func Validate(md metadata.MD) error {
+	for k, vals := range md {
+		// pseudo-header will be ignored
+		if k[0] == ':' {
+			continue
+		}
+		// check key, for i that saving a conversion if not using for range
+		for i := 0; i < len(k); i++ {
+			r := k[i]
+			if !(r >= 'a' && r <= 'z') && !(r >= '0' && r <= '9') && r != '.' && r != '-' && r != '_' {
+				return fmt.Errorf("header key %q contains illegal characters not in [0-9a-z-_.]", k)
+			}
+		}
+		if strings.HasSuffix(k, "-bin") {
+			continue
+		}
+		// check value
+		for _, val := range vals {
+			if hasNotPrintable(val) {
+				return fmt.Errorf("header key %q contains value with non-printable ASCII characters", k)
+			}
+		}
+	}
+	return nil
+}
+
+// hasNotPrintable return true if msg contains any characters which are not in %x20-%x7E
+func hasNotPrintable(msg string) bool {
+	// for i that saving a conversion if not using for range
+	for i := 0; i < len(msg); i++ {
+		if msg[i] < 0x20 || msg[i] > 0x7E {
+			return true
+		}
+	}
+	return false
+}
@@ -0,0 +1,82 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package pretty defines helper functions to pretty-print structs for logging.
+package pretty
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+
+	"github.com/golang/protobuf/jsonpb"
+	protov1 "github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/encoding/protojson"
+	protov2 "google.golang.org/protobuf/proto"
+)
+
+const jsonIndent = "  "
+
+// ToJSON marshals the input into a json string.
+//
+// If marshal fails, it falls back to fmt.Sprintf("%+v").
+func ToJSON(e interface{}) string {
+	switch ee := e.(type) {
+	case protov1.Message:
+		mm := jsonpb.Marshaler{Indent: jsonIndent}
+		ret, err := mm.MarshalToString(ee)
+		if err != nil {
+			// This may fail for proto.Anys, e.g. for xDS v2, LDS, the v2
+			// messages are not imported, and this will fail because the message
+			// is not found.
+			return fmt.Sprintf("%+v", ee)
+		}
+		return ret
+	case protov2.Message:
+		mm := protojson.MarshalOptions{
+			Multiline: true,
+			Indent:    jsonIndent,
+		}
+		ret, err := mm.Marshal(ee)
+		if err != nil {
+			// This may fail for proto.Anys, e.g. for xDS v2, LDS, the v2
+			// messages are not imported, and this will fail because the message
+			// is not found.
+			return fmt.Sprintf("%+v", ee)
+		}
+		return string(ret)
+	default:
+		ret, err := json.MarshalIndent(ee, "", jsonIndent)
+		if err != nil {
+			return fmt.Sprintf("%+v", ee)
+		}
+		return string(ret)
+	}
+}
+
+// FormatJSON formats the input json bytes with indentation.
+//
+// If Indent fails, it returns the unchanged input as string.
+func FormatJSON(b []byte) string {
+	var out bytes.Buffer
+	err := json.Indent(&out, b, "", jsonIndent)
+	if err != nil {
+		return string(b)
+	}
+	return out.String()
+}
@@ -137,6 +137,7 @@ type earlyAbortStream struct {
 	streamID       uint32
 	contentSubtype string
 	status         *status.Status
+	rst            bool
 }

 func (*earlyAbortStream) isTransportResponseFrame() bool { return false }
@@ -786,6 +787,11 @@ func (l *loopyWriter) earlyAbortStreamHandler(eas *earlyAbortStream) error {
 	if err := l.writeHeader(eas.streamID, true, headerFields, nil); err != nil {
 		return err
 	}
+	if eas.rst {
+		if err := l.framer.fr.WriteRSTStream(eas.streamID, http2.ErrCodeNo); err != nil {
+			return err
+		}
+	}
 	return nil
 }

@@ -132,7 +132,7 @@ type http2Client struct {
 	kpDormant bool

 	// Fields below are for channelz metric collection.
-	channelzID int64 // channelz unique identification number
+	channelzID *channelz.Identifier
 	czData     *channelzData

 	onGoAway func(GoAwayReason)
@@ -351,8 +351,9 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 		}
 		t.statsHandler.HandleConn(t.ctx, connBegin)
 	}
-	if channelz.IsOn() {
-		t.channelzID = channelz.RegisterNormalSocket(t, opts.ChannelzParentID, fmt.Sprintf("%s -> %s", t.localAddr, t.remoteAddr))
+	t.channelzID, err = channelz.RegisterNormalSocket(t, opts.ChannelzParentID, fmt.Sprintf("%s -> %s", t.localAddr, t.remoteAddr))
+	if err != nil {
+		return nil, err
 	}
 	if t.keepaliveEnabled {
 		t.kpDormancyCond = sync.NewCond(&t.mu)
@@ -630,8 +631,8 @@ func (t *http2Client) getCallAuthData(ctx context.Context, audience string, call
 // the wire.  However, there are two notable exceptions:
 //
 // 1. If the stream headers violate the max header list size allowed by the
-//    server.  In this case there is no reason to retry at all, as it is
-//    assumed the RPC would continue to fail on subsequent attempts.
+//    server.  It's possible this could succeed on another transport, even if
+//    it's unlikely, but do not transparently retry.
 // 2. If the credentials errored when requesting their headers.  In this case,
 //    it's possible a retry can fix the problem, but indefinitely transparently
 //    retrying is not appropriate as it is likely the credentials, if they can
@@ -639,8 +640,7 @@ func (t *http2Client) getCallAuthData(ctx context.Context, audience string, call
 type NewStreamError struct {
 	Err error

-	DoNotRetry            bool
-	DoNotTransparentRetry bool
+	AllowTransparentRetry bool
 }

 func (e NewStreamError) Error() string {
@@ -649,11 +649,11 @@ func (e NewStreamError) Error() string {

 // NewStream creates a stream and registers it into the transport as "active"
 // streams.  All non-nil errors returned will be *NewStreamError.
-func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Stream, err error) {
+func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (*Stream, error) {
 	ctx = peer.NewContext(ctx, t.getPeer())
 	headerFields, err := t.createHeaderFields(ctx, callHdr)
 	if err != nil {
-		return nil, &NewStreamError{Err: err, DoNotTransparentRetry: true}
+		return nil, &NewStreamError{Err: err, AllowTransparentRetry: false}
 	}
 	s := t.newStream(ctx, callHdr)
 	cleanup := func(err error) {
@@ -753,13 +753,14 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 			return true
 		}, hdr)
 		if err != nil {
-			return nil, &NewStreamError{Err: err}
+			// Connection closed.
+			return nil, &NewStreamError{Err: err, AllowTransparentRetry: true}
 		}
 		if success {
 			break
 		}
 		if hdrListSizeErr != nil {
-			return nil, &NewStreamError{Err: hdrListSizeErr, DoNotRetry: true}
+			return nil, &NewStreamError{Err: hdrListSizeErr}
 		}
 		firstTry = false
 		select {
@@ -767,9 +768,9 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 		case <-ctx.Done():
 			return nil, &NewStreamError{Err: ContextErr(ctx.Err())}
 		case <-t.goAway:
-			return nil, &NewStreamError{Err: errStreamDrain}
+			return nil, &NewStreamError{Err: errStreamDrain, AllowTransparentRetry: true}
 		case <-t.ctx.Done():
-			return nil, &NewStreamError{Err: ErrConnClosing}
+			return nil, &NewStreamError{Err: ErrConnClosing, AllowTransparentRetry: true}
 		}
 	}
 	if t.statsHandler != nil {
@@ -898,9 +899,7 @@ func (t *http2Client) Close(err error) {
 	t.controlBuf.finish()
 	t.cancel()
 	t.conn.Close()
-	if channelz.IsOn() {
-		channelz.RemoveEntry(t.channelzID)
-	}
+	channelz.RemoveEntry(t.channelzID)
 	// Append info about previous goaways if there were any, since this may be important
 	// for understanding the root cause for this connection to be closed.
 	_, goAwayDebugMessage := t.GetGoAwayReason()
@@ -21,7 +21,6 @@ package transport
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -36,6 +35,7 @@ import (
 	"golang.org/x/net/http2"
 	"golang.org/x/net/http2/hpack"
 	"google.golang.org/grpc/internal/grpcutil"
+	"google.golang.org/grpc/internal/syscall"

 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
@@ -52,10 +52,10 @@ import (
 var (
 	// ErrIllegalHeaderWrite indicates that setting header is illegal because of
 	// the stream's state.
-	ErrIllegalHeaderWrite = errors.New("transport: the stream is done or WriteHeader was already called")
+	ErrIllegalHeaderWrite = status.Error(codes.Internal, "transport: SendHeader called multiple times")
 	// ErrHeaderListSizeLimitViolation indicates that the header list size is larger
 	// than the limit set by peer.
-	ErrHeaderListSizeLimitViolation = errors.New("transport: trying to send header list size larger than the limit set by peer")
+	ErrHeaderListSizeLimitViolation = status.Error(codes.Internal, "transport: trying to send header list size larger than the limit set by peer")
 )

 // serverConnectionCounter counts the number of connections a server has seen
@@ -117,7 +117,7 @@ type http2Server struct {
 	idle time.Time

 	// Fields below are for channelz metric collection.
-	channelzID int64 // channelz unique identification number
+	channelzID *channelz.Identifier
 	czData     *channelzData
 	bufferPool *bufferPool

@@ -231,6 +231,11 @@ func NewServerTransport(conn net.Conn, config *ServerConfig) (_ ServerTransport,
 	if kp.Timeout == 0 {
 		kp.Timeout = defaultServerKeepaliveTimeout
 	}
+	if kp.Time != infinity {
+		if err = syscall.SetTCPUserTimeout(conn, kp.Timeout); err != nil {
+			return nil, connectionErrorf(false, err, "transport: failed to set TCP_USER_TIMEOUT: %v", err)
+		}
+	}
 	kep := config.KeepalivePolicy
 	if kep.MinTime == 0 {
 		kep.MinTime = defaultKeepalivePolicyMinTime
@@ -275,12 +280,12 @@ func NewServerTransport(conn net.Conn, config *ServerConfig) (_ ServerTransport,
 		connBegin := &stats.ConnBegin{}
 		t.stats.HandleConn(t.ctx, connBegin)
 	}
-	if channelz.IsOn() {
-		t.channelzID = channelz.RegisterNormalSocket(t, config.ChannelzParentID, fmt.Sprintf("%s -> %s", t.remoteAddr, t.localAddr))
+	t.channelzID, err = channelz.RegisterNormalSocket(t, config.ChannelzParentID, fmt.Sprintf("%s -> %s", t.remoteAddr, t.localAddr))
+	if err != nil {
+		return nil, err
 	}

 	t.connectionID = atomic.AddUint64(&serverConnectionCounter, 1)
-
 	t.framer.writer.Flush()

 	defer func() {
@@ -443,6 +448,7 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 			streamID:       streamID,
 			contentSubtype: s.contentSubtype,
 			status:         status.New(codes.Internal, errMsg),
+			rst:            !frame.StreamEnded(),
 		})
 		return false
 	}
@@ -516,14 +522,16 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 	}
 	if httpMethod != http.MethodPost {
 		t.mu.Unlock()
+		errMsg := fmt.Sprintf("http2Server.operateHeaders parsed a :method field: %v which should be POST", httpMethod)
 		if logger.V(logLevel) {
-			logger.Infof("transport: http2Server.operateHeaders parsed a :method field: %v which should be POST", httpMethod)
+			logger.Infof("transport: %v", errMsg)
 		}
-		t.controlBuf.put(&cleanupStream{
-			streamID: streamID,
-			rst:      true,
-			rstCode:  http2.ErrCodeProtocol,
-			onWrite:  func() {},
+		t.controlBuf.put(&earlyAbortStream{
+			httpStatus:     405,
+			streamID:       streamID,
+			contentSubtype: s.contentSubtype,
+			status:         status.New(codes.Internal, errMsg),
+			rst:            !frame.StreamEnded(),
 		})
 		s.cancel()
 		return false
@@ -544,6 +552,7 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 				streamID:       s.id,
 				contentSubtype: s.contentSubtype,
 				status:         stat,
+				rst:            !frame.StreamEnded(),
 			})
 			return false
 		}
@@ -925,11 +934,25 @@ func (t *http2Server) checkForHeaderListSize(it interface{}) bool {
 	return true
 }

+func (t *http2Server) streamContextErr(s *Stream) error {
+	select {
+	case <-t.done:
+		return ErrConnClosing
+	default:
+	}
+	return ContextErr(s.ctx.Err())
+}
+
 // WriteHeader sends the header metadata md back to the client.
 func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
-	if s.updateHeaderSent() || s.getState() == streamDone {
+	if s.updateHeaderSent() {
 		return ErrIllegalHeaderWrite
 	}
+
+	if s.getState() == streamDone {
+		return t.streamContextErr(s)
+	}
+
 	s.hdrMu.Lock()
 	if md.Len() > 0 {
 		if s.header.Len() > 0 {
@@ -940,7 +963,7 @@ func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
 	}
 	if err := t.writeHeaderLocked(s); err != nil {
 		s.hdrMu.Unlock()
-		return err
+		return status.Convert(err).Err()
 	}
 	s.hdrMu.Unlock()
 	return nil
@@ -1056,23 +1079,12 @@ func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
 func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) error {
 	if !s.isHeaderSent() { // Headers haven't been written yet.
 		if err := t.WriteHeader(s, nil); err != nil {
-			if _, ok := err.(ConnectionError); ok {
-				return err
-			}
-			// TODO(mmukhi, dfawley): Make sure this is the right code to return.
-			return status.Errorf(codes.Internal, "transport: %v", err)
+			return err
 		}
 	} else {
 		// Writing headers checks for this condition.
 		if s.getState() == streamDone {
-			// TODO(mmukhi, dfawley): Should the server write also return io.EOF?
-			s.cancel()
-			select {
-			case <-t.done:
-				return ErrConnClosing
-			default:
-			}
-			return ContextErr(s.ctx.Err())
+			return t.streamContextErr(s)
 		}
 	}
 	df := &dataFrame{
@@ -1082,12 +1094,7 @@ func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) e
 		onEachWrite: t.setResetPingStrikes,
 	}
 	if err := s.wq.get(int32(len(hdr) + len(data))); err != nil {
-		select {
-		case <-t.done:
-			return ErrConnClosing
-		default:
-		}
-		return ContextErr(s.ctx.Err())
+		return t.streamContextErr(s)
 	}
 	return t.controlBuf.put(df)
 }
@@ -1210,9 +1217,7 @@ func (t *http2Server) Close() {
 	if err := t.conn.Close(); err != nil && logger.V(logLevel) {
 		logger.Infof("transport: error closing conn during Close: %v", err)
 	}
-	if channelz.IsOn() {
-		channelz.RemoveEntry(t.channelzID)
-	}
+	channelz.RemoveEntry(t.channelzID)
 	// Cancel all active streams.
 	for _, s := range streams {
 		s.cancel()
@@ -1225,10 +1230,6 @@ func (t *http2Server) Close() {

 // deleteStream deletes the stream s from transport's active streams.
 func (t *http2Server) deleteStream(s *Stream, eosReceived bool) {
-	// In case stream sending and receiving are invoked in separate
-	// goroutines (e.g., bi-directional streaming), cancel needs to be
-	// called to interrupt the potential blocking on other goroutines.
-	s.cancel()

 	t.mu.Lock()
 	if _, ok := t.activeStreams[s.id]; ok {
@@ -1250,6 +1251,11 @@ func (t *http2Server) deleteStream(s *Stream, eosReceived bool) {

 // finishStream closes the stream and puts the trailing headerFrame into controlbuf.
 func (t *http2Server) finishStream(s *Stream, rst bool, rstCode http2.ErrCode, hdr *headerFrame, eosReceived bool) {
+	// In case stream sending and receiving are invoked in separate
+	// goroutines (e.g., bi-directional streaming), cancel needs to be
+	// called to interrupt the potential blocking on other goroutines.
+	s.cancel()
+
 	oldState := s.swapState(streamDone)
 	if oldState == streamDone {
 		// If the stream was already done, return.
@@ -1269,6 +1275,11 @@ func (t *http2Server) finishStream(s *Stream, rst bool, rstCode http2.ErrCode, h

 // closeStream clears the footprint of a stream when the stream is not needed any more.
 func (t *http2Server) closeStream(s *Stream, rst bool, rstCode http2.ErrCode, eosReceived bool) {
+	// In case stream sending and receiving are invoked in separate
+	// goroutines (e.g., bi-directional streaming), cancel needs to be
+	// called to interrupt the potential blocking on other goroutines.
+	s.cancel()
+
 	s.swapState(streamDone)
 	t.deleteStream(s, eosReceived)

@@ -34,6 +34,7 @@ import (

 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/resolver"
@@ -529,7 +530,7 @@ type ServerConfig struct {
 	InitialConnWindowSize int32
 	WriteBufferSize       int
 	ReadBufferSize        int
-	ChannelzParentID      int64
+	ChannelzParentID      *channelz.Identifier
 	MaxHeaderListSize     *uint32
 	HeaderTableSize       *uint32
 }
@@ -563,7 +564,7 @@ type ConnectOptions struct {
 	// ReadBufferSize sets the size of read buffer, which in turn determines how much data can be read at most for one read syscall.
 	ReadBufferSize int
 	// ChannelzParentID sets the addrConn id which initiate the creation of this client transport.
-	ChannelzParentID int64
+	ChannelzParentID *channelz.Identifier
 	// MaxHeaderListSize sets the max (uncompressed) size of header list that is prepared to be received.
 	MaxHeaderListSize *uint32
 	// UseProxy specifies if a proxy should be used.
@@ -188,7 +188,9 @@ func FromIncomingContext(ctx context.Context) (MD, bool) {
 		// map, and there's no guarantee that the MD attached to the context is
 		// created using our helper functions.
 		key := strings.ToLower(k)
-		out[key] = v
+		s := make([]string, len(v))
+		copy(s, v)
+		out[key] = s
 	}
 	return out, true
 }
@@ -226,7 +228,9 @@ func FromOutgoingContext(ctx context.Context) (MD, bool) {
 		// map, and there's no guarantee that the MD attached to the context is
 		// created using our helper functions.
 		key := strings.ToLower(k)
-		out[key] = v
+		s := make([]string, len(v))
+		copy(s, v)
+		out[key] = s
 	}
 	for _, added := range raw.added {
 		if len(added)%2 == 1 {
@@ -131,7 +131,7 @@ func (pw *pickerWrapper) pick(ctx context.Context, failfast bool, info balancer.
 			}
 			if _, ok := status.FromError(err); ok {
 				// Status error: end the RPC unconditionally with this status.
-				return nil, nil, err
+				return nil, nil, dropError{error: err}
 			}
 			// For all other errors, wait for ready RPCs should block and other
 			// RPCs should fail with unavailable.
@@ -175,3 +175,9 @@ func (pw *pickerWrapper) close() {
 	pw.done = true
 	close(pw.blockingCh)
 }
+
+// dropError is a wrapper error that indicates the LB policy wishes to drop the
+// RPC and not retry it.
+type dropError struct {
+	error
+}
@@ -44,79 +44,107 @@ func (*pickfirstBuilder) Name() string {
 }

 type pickfirstBalancer struct {
-	state connectivity.State
-	cc    balancer.ClientConn
-	sc    balancer.SubConn
+	state   connectivity.State
+	cc      balancer.ClientConn
+	subConn balancer.SubConn
 }

 func (b *pickfirstBalancer) ResolverError(err error) {
-	switch b.state {
-	case connectivity.TransientFailure, connectivity.Idle, connectivity.Connecting:
-		// Set a failing picker if we don't have a good picker.
-		b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.TransientFailure,
-			Picker: &picker{err: fmt.Errorf("name resolver error: %v", err)},
-		})
-	}
 	if logger.V(2) {
 		logger.Infof("pickfirstBalancer: ResolverError called with error %v", err)
 	}
+	if b.subConn == nil {
+		b.state = connectivity.TransientFailure
+	}
+
+	if b.state != connectivity.TransientFailure {
+		// The picker will not change since the balancer does not currently
+		// report an error.
+		return
+	}
+	b.cc.UpdateState(balancer.State{
+		ConnectivityState: connectivity.TransientFailure,
+		Picker:            &picker{err: fmt.Errorf("name resolver error: %v", err)},
+	})
 }

-func (b *pickfirstBalancer) UpdateClientConnState(cs balancer.ClientConnState) error {
-	if len(cs.ResolverState.Addresses) == 0 {
+func (b *pickfirstBalancer) UpdateClientConnState(state balancer.ClientConnState) error {
+	if len(state.ResolverState.Addresses) == 0 {
+		// The resolver reported an empty address list. Treat it like an error by
+		// calling b.ResolverError.
+		if b.subConn != nil {
+			// Remove the old subConn. All addresses were removed, so it is no longer
+			// valid.
+			b.cc.RemoveSubConn(b.subConn)
+			b.subConn = nil
+		}
 		b.ResolverError(errors.New("produced zero addresses"))
 		return balancer.ErrBadResolverState
 	}
-	if b.sc == nil {
-		var err error
-		b.sc, err = b.cc.NewSubConn(cs.ResolverState.Addresses, balancer.NewSubConnOptions{})
-		if err != nil {
-			if logger.V(2) {
-				logger.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
-			}
-			b.state = connectivity.TransientFailure
-			b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.TransientFailure,
-				Picker: &picker{err: fmt.Errorf("error creating connection: %v", err)},
-			})
-			return balancer.ErrBadResolverState
-		}
-		b.state = connectivity.Idle
-		b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.Idle, Picker: &picker{result: balancer.PickResult{SubConn: b.sc}}})
-		b.sc.Connect()
-	} else {
-		b.cc.UpdateAddresses(b.sc, cs.ResolverState.Addresses)
-		b.sc.Connect()
+
+	if b.subConn != nil {
+		b.cc.UpdateAddresses(b.subConn, state.ResolverState.Addresses)
+		return nil
 	}
+
+	subConn, err := b.cc.NewSubConn(state.ResolverState.Addresses, balancer.NewSubConnOptions{})
+	if err != nil {
+		if logger.V(2) {
+			logger.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
+		}
+		b.state = connectivity.TransientFailure
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: connectivity.TransientFailure,
+			Picker:            &picker{err: fmt.Errorf("error creating connection: %v", err)},
+		})
+		return balancer.ErrBadResolverState
+	}
+	b.subConn = subConn
+	b.state = connectivity.Idle
+	b.cc.UpdateState(balancer.State{
+		ConnectivityState: connectivity.Idle,
+		Picker:            &picker{result: balancer.PickResult{SubConn: b.subConn}},
+	})
+	b.subConn.Connect()
 	return nil
 }

-func (b *pickfirstBalancer) UpdateSubConnState(sc balancer.SubConn, s balancer.SubConnState) {
+func (b *pickfirstBalancer) UpdateSubConnState(subConn balancer.SubConn, state balancer.SubConnState) {
 	if logger.V(2) {
-		logger.Infof("pickfirstBalancer: UpdateSubConnState: %p, %v", sc, s)
+		logger.Infof("pickfirstBalancer: UpdateSubConnState: %p, %v", subConn, state)
 	}
-	if b.sc != sc {
+	if b.subConn != subConn {
 		if logger.V(2) {
-			logger.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+			logger.Infof("pickfirstBalancer: ignored state change because subConn is not recognized")
 		}
 		return
 	}
-	b.state = s.ConnectivityState
-	if s.ConnectivityState == connectivity.Shutdown {
-		b.sc = nil
+	b.state = state.ConnectivityState
+	if state.ConnectivityState == connectivity.Shutdown {
+		b.subConn = nil
 		return
 	}

-	switch s.ConnectivityState {
+	switch state.ConnectivityState {
 	case connectivity.Ready:
-		b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &picker{result: balancer.PickResult{SubConn: sc}}})
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: state.ConnectivityState,
+			Picker:            &picker{result: balancer.PickResult{SubConn: subConn}},
+		})
 	case connectivity.Connecting:
-		b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &picker{err: balancer.ErrNoSubConnAvailable}})
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: state.ConnectivityState,
+			Picker:            &picker{err: balancer.ErrNoSubConnAvailable},
+		})
 	case connectivity.Idle:
-		b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &idlePicker{sc: sc}})
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: state.ConnectivityState,
+			Picker:            &idlePicker{subConn: subConn},
+		})
 	case connectivity.TransientFailure:
 		b.cc.UpdateState(balancer.State{
-			ConnectivityState: s.ConnectivityState,
-			Picker:            &picker{err: s.ConnectionError},
+			ConnectivityState: state.ConnectivityState,
+			Picker:            &picker{err: state.ConnectionError},
 		})
 	}
 }
@@ -125,8 +153,8 @@ func (b *pickfirstBalancer) Close() {
 }

 func (b *pickfirstBalancer) ExitIdle() {
-	if b.sc != nil && b.state == connectivity.Idle {
-		b.sc.Connect()
+	if b.subConn != nil && b.state == connectivity.Idle {
+		b.subConn.Connect()
 	}
 }

@@ -135,18 +163,18 @@ type picker struct {
 	err    error
 }

-func (p *picker) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
+func (p *picker) Pick(balancer.PickInfo) (balancer.PickResult, error) {
 	return p.result, p.err
 }

 // idlePicker is used when the SubConn is IDLE and kicks the SubConn into
 // CONNECTING when Pick is called.
 type idlePicker struct {
-	sc balancer.SubConn
+	subConn balancer.SubConn
 }

-func (i *idlePicker) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
-	i.sc.Connect()
+func (i *idlePicker) Pick(balancer.PickInfo) (balancer.PickResult, error) {
+	i.subConn.Connect()
 	return balancer.PickResult{}, balancer.ErrNoSubConnAvailable
 }

@@ -27,6 +27,7 @@ import (

 	"google.golang.org/grpc/attributes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/internal/pretty"
 	"google.golang.org/grpc/serviceconfig"
 )

@@ -139,13 +140,18 @@ type Address struct {

 // Equal returns whether a and o are identical.  Metadata is compared directly,
 // not with any recursive introspection.
-func (a *Address) Equal(o Address) bool {
+func (a Address) Equal(o Address) bool {
 	return a.Addr == o.Addr && a.ServerName == o.ServerName &&
 		a.Attributes.Equal(o.Attributes) &&
 		a.BalancerAttributes.Equal(o.BalancerAttributes) &&
 		a.Type == o.Type && a.Metadata == o.Metadata
 }

+// String returns JSON formatted string representation of the address.
+func (a Address) String() string {
+	return pretty.ToJSON(a)
+}
+
 // BuildOptions includes additional information for the builder to create
 // the resolver.
 type BuildOptions struct {
@@ -19,7 +19,6 @@
 package grpc

 import (
-	"fmt"
 	"strings"
 	"sync"

@@ -27,6 +26,7 @@ import (
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcsync"
+	"google.golang.org/grpc/internal/pretty"
 	"google.golang.org/grpc/resolver"
 	"google.golang.org/grpc/serviceconfig"
 )
@@ -97,10 +97,7 @@ func (ccr *ccResolverWrapper) UpdateState(s resolver.State) error {
 	if ccr.done.HasFired() {
 		return nil
 	}
-	channelz.Infof(logger, ccr.cc.channelzID, "ccResolverWrapper: sending update to cc: %v", s)
-	if channelz.IsOn() {
-		ccr.addChannelzTraceEvent(s)
-	}
+	ccr.addChannelzTraceEvent(s)
 	ccr.curState = s
 	if err := ccr.cc.updateResolverState(ccr.curState, nil); err == balancer.ErrBadResolverState {
 		return balancer.ErrBadResolverState
@@ -125,10 +122,7 @@ func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
 	if ccr.done.HasFired() {
 		return
 	}
-	channelz.Infof(logger, ccr.cc.channelzID, "ccResolverWrapper: sending new addresses to cc: %v", addrs)
-	if channelz.IsOn() {
-		ccr.addChannelzTraceEvent(resolver.State{Addresses: addrs, ServiceConfig: ccr.curState.ServiceConfig})
-	}
+	ccr.addChannelzTraceEvent(resolver.State{Addresses: addrs, ServiceConfig: ccr.curState.ServiceConfig})
 	ccr.curState.Addresses = addrs
 	ccr.cc.updateResolverState(ccr.curState, nil)
 }
@@ -141,7 +135,7 @@ func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
 	if ccr.done.HasFired() {
 		return
 	}
-	channelz.Infof(logger, ccr.cc.channelzID, "ccResolverWrapper: got new service config: %v", sc)
+	channelz.Infof(logger, ccr.cc.channelzID, "ccResolverWrapper: got new service config: %s", sc)
 	if ccr.cc.dopts.disableServiceConfig {
 		channelz.Info(logger, ccr.cc.channelzID, "Service config lookups disabled; ignoring config")
 		return
@@ -151,9 +145,7 @@ func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
 		channelz.Warningf(logger, ccr.cc.channelzID, "ccResolverWrapper: error parsing service config: %v", scpr.Err)
 		return
 	}
-	if channelz.IsOn() {
-		ccr.addChannelzTraceEvent(resolver.State{Addresses: ccr.curState.Addresses, ServiceConfig: scpr})
-	}
+	ccr.addChannelzTraceEvent(resolver.State{Addresses: ccr.curState.Addresses, ServiceConfig: scpr})
 	ccr.curState.ServiceConfig = scpr
 	ccr.cc.updateResolverState(ccr.curState, nil)
 }
@@ -180,8 +172,5 @@ func (ccr *ccResolverWrapper) addChannelzTraceEvent(s resolver.State) {
 	} else if len(ccr.curState.Addresses) == 0 && len(s.Addresses) > 0 {
 		updates = append(updates, "resolver returned new addresses")
 	}
-	channelz.AddTraceEvent(logger, ccr.cc.channelzID, 0, &channelz.TraceEventDesc{
-		Desc:     fmt.Sprintf("Resolver state updated: %+v (%v)", s, strings.Join(updates, "; ")),
-		Severity: channelz.CtInfo,
-	})
+	channelz.Infof(logger, ccr.cc.channelzID, "Resolver state updated: %s (%v)", pretty.ToJSON(s), strings.Join(updates, "; "))
 }
@@ -134,7 +134,7 @@ type Server struct {
 	channelzRemoveOnce sync.Once
 	serveWG            sync.WaitGroup // counts active Serve goroutines for GracefulStop

-	channelzID int64 // channelz unique identification number
+	channelzID *channelz.Identifier
 	czData     *channelzData

 	serverWorkerChannels []chan *serverWorkerData
@@ -584,9 +584,8 @@ func NewServer(opt ...ServerOption) *Server {
 		s.initServerWorkers()
 	}

-	if channelz.IsOn() {
-		s.channelzID = channelz.RegisterServer(&channelzServer{s}, "")
-	}
+	s.channelzID = channelz.RegisterServer(&channelzServer{s}, "")
+	channelz.Info(logger, s.channelzID, "Server created")
 	return s
 }

@@ -712,7 +711,7 @@ var ErrServerStopped = errors.New("grpc: the server has been stopped")

 type listenSocket struct {
 	net.Listener
-	channelzID int64
+	channelzID *channelz.Identifier
 }

 func (l *listenSocket) ChannelzMetric() *channelz.SocketInternalMetric {
@@ -724,9 +723,8 @@ func (l *listenSocket) ChannelzMetric() *channelz.SocketInternalMetric {

 func (l *listenSocket) Close() error {
 	err := l.Listener.Close()
-	if channelz.IsOn() {
-		channelz.RemoveEntry(l.channelzID)
-	}
+	channelz.RemoveEntry(l.channelzID)
+	channelz.Info(logger, l.channelzID, "ListenSocket deleted")
 	return err
 }

@@ -759,11 +757,6 @@ func (s *Server) Serve(lis net.Listener) error {
 	ls := &listenSocket{Listener: lis}
 	s.lis[ls] = true

-	if channelz.IsOn() {
-		ls.channelzID = channelz.RegisterListenSocket(ls, s.channelzID, lis.Addr().String())
-	}
-	s.mu.Unlock()
-
 	defer func() {
 		s.mu.Lock()
 		if s.lis != nil && s.lis[ls] {
@@ -773,8 +766,16 @@ func (s *Server) Serve(lis net.Listener) error {
 		s.mu.Unlock()
 	}()

-	var tempDelay time.Duration // how long to sleep on accept failure
+	var err error
+	ls.channelzID, err = channelz.RegisterListenSocket(ls, s.channelzID, lis.Addr().String())
+	if err != nil {
+		s.mu.Unlock()
+		return err
+	}
+	s.mu.Unlock()
+	channelz.Info(logger, ls.channelzID, "ListenSocket created")

+	var tempDelay time.Duration // how long to sleep on accept failure
 	for {
 		rawConn, err := lis.Accept()
 		if err != nil {
@@ -1709,11 +1710,7 @@ func (s *Server) Stop() {
 		s.done.Fire()
 	}()

-	s.channelzRemoveOnce.Do(func() {
-		if channelz.IsOn() {
-			channelz.RemoveEntry(s.channelzID)
-		}
-	})
+	s.channelzRemoveOnce.Do(func() { channelz.RemoveEntry(s.channelzID) })

 	s.mu.Lock()
 	listeners := s.lis
@@ -1751,11 +1748,7 @@ func (s *Server) GracefulStop() {
 	s.quit.Fire()
 	defer s.done.Fire()

-	s.channelzRemoveOnce.Do(func() {
-		if channelz.IsOn() {
-			channelz.RemoveEntry(s.channelzID)
-		}
-	})
+	s.channelzRemoveOnce.Do(func() { channelz.RemoveEntry(s.channelzID) })
 	s.mu.Lock()
 	if s.conns == nil {
 		s.mu.Unlock()
@@ -1808,12 +1801,26 @@ func (s *Server) getCodec(contentSubtype string) baseCodec {
 	return codec
 }

-// SetHeader sets the header metadata.
-// When called multiple times, all the provided metadata will be merged.
-// All the metadata will be sent out when one of the following happens:
-//  - grpc.SendHeader() is called;
-//  - The first response is sent out;
-//  - An RPC status is sent out (error or success).
+// SetHeader sets the header metadata to be sent from the server to the client.
+// The context provided must be the context passed to the server's handler.
+//
+// Streaming RPCs should prefer the SetHeader method of the ServerStream.
+//
+// When called multiple times, all the provided metadata will be merged.  All
+// the metadata will be sent out when one of the following happens:
+//
+// - grpc.SendHeader is called, or for streaming handlers, stream.SendHeader.
+// - The first response message is sent.  For unary handlers, this occurs when
+//   the handler returns; for streaming handlers, this can happen when stream's
+//   SendMsg method is called.
+// - An RPC status is sent out (error or success).  This occurs when the handler
+//   returns.
+//
+// SetHeader will fail if called after any of the events above.
+//
+// The error returned is compatible with the status package.  However, the
+// status code will often not match the RPC status as seen by the client
+// application, and therefore, should not be relied upon for this purpose.
 func SetHeader(ctx context.Context, md metadata.MD) error {
 	if md.Len() == 0 {
 		return nil
@@ -1825,8 +1832,14 @@ func SetHeader(ctx context.Context, md metadata.MD) error {
 	return stream.SetHeader(md)
 }

-// SendHeader sends header metadata. It may be called at most once.
-// The provided md and headers set by SetHeader() will be sent.
+// SendHeader sends header metadata. It may be called at most once, and may not
+// be called after any event that causes headers to be sent (see SetHeader for
+// a complete list).  The provided md and headers set by SetHeader() will be
+// sent.
+//
+// The error returned is compatible with the status package.  However, the
+// status code will often not match the RPC status as seen by the client
+// application, and therefore, should not be relied upon for this purpose.
 func SendHeader(ctx context.Context, md metadata.MD) error {
 	stream := ServerTransportStreamFromContext(ctx)
 	if stream == nil {
@@ -1840,6 +1853,10 @@ func SendHeader(ctx context.Context, md metadata.MD) error {

 // SetTrailer sets the trailer metadata that will be sent when an RPC returns.
 // When called more than once, all the provided metadata will be merged.
+//
+// The error returned is compatible with the status package.  However, the
+// status code will often not match the RPC status as seen by the client
+// application, and therefore, should not be relied upon for this purpose.
 func SetTrailer(ctx context.Context, md metadata.MD) error {
 	if md.Len() == 0 {
 		return nil
@@ -381,6 +381,9 @@ func init() {
 //
 // If any of them is NOT *ServiceConfig, return false.
 func equalServiceConfig(a, b serviceconfig.Config) bool {
+	if a == nil && b == nil {
+		return true
+	}
 	aa, ok := a.(*ServiceConfig)
 	if !ok {
 		return false
@@ -36,6 +36,7 @@ import (
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcrand"
 	"google.golang.org/grpc/internal/grpcutil"
+	imetadata "google.golang.org/grpc/internal/metadata"
 	iresolver "google.golang.org/grpc/internal/resolver"
 	"google.golang.org/grpc/internal/serviceconfig"
 	"google.golang.org/grpc/internal/transport"
@@ -166,6 +167,11 @@ func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 }

 func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
+	if md, _, ok := metadata.FromOutgoingContextRaw(ctx); ok {
+		if err := imetadata.Validate(md); err != nil {
+			return nil, status.Error(codes.Internal, err.Error())
+		}
+	}
 	if channelz.IsOn() {
 		cc.incrCallsStarted()
 		defer func() {
@@ -297,14 +303,28 @@ func newClientStreamWithParams(ctx context.Context, desc *StreamDesc, cc *Client
 	}
 	cs.binlog = binarylog.GetMethodLogger(method)

-	if err := cs.newAttemptLocked(false /* isTransparent */); err != nil {
+	cs.attempt, err = cs.newAttemptLocked(false /* isTransparent */)
+	if err != nil {
 		cs.finish(err)
 		return nil, err
 	}

-	op := func(a *csAttempt) error { return a.newStream() }
+	// Pick the transport to use and create a new stream on the transport.
+	// Assign cs.attempt upon success.
+	op := func(a *csAttempt) error {
+		if err := a.getTransport(); err != nil {
+			return err
+		}
+		if err := a.newStream(); err != nil {
+			return err
+		}
+		// Because this operation is always called either here (while creating
+		// the clientStream) or by the retry code while locked when replaying
+		// the operation, it is safe to access cs.attempt directly.
+		cs.attempt = a
+		return nil
+	}
 	if err := cs.withRetry(op, func() { cs.bufferForRetryLocked(0, op) }); err != nil {
-		cs.finish(err)
 		return nil, err
 	}

@@ -343,9 +363,15 @@ func newClientStreamWithParams(ctx context.Context, desc *StreamDesc, cc *Client
 	return cs, nil
 }

-// newAttemptLocked creates a new attempt with a transport.
-// If it succeeds, then it replaces clientStream's attempt with this new attempt.
-func (cs *clientStream) newAttemptLocked(isTransparent bool) (retErr error) {
+// newAttemptLocked creates a new csAttempt without a transport or stream.
+func (cs *clientStream) newAttemptLocked(isTransparent bool) (*csAttempt, error) {
+	if err := cs.ctx.Err(); err != nil {
+		return nil, toRPCErr(err)
+	}
+	if err := cs.cc.ctx.Err(); err != nil {
+		return nil, ErrClientConnClosing
+	}
+
 	ctx := newContextWithRPCInfo(cs.ctx, cs.callInfo.failFast, cs.callInfo.codec, cs.cp, cs.comp)
 	method := cs.callHdr.Method
 	sh := cs.cc.dopts.copts.StatsHandler
@@ -379,27 +405,6 @@ func (cs *clientStream) newAttemptLocked(isTransparent bool) (retErr error) {
 		ctx = trace.NewContext(ctx, trInfo.tr)
 	}

-	newAttempt := &csAttempt{
-		ctx:          ctx,
-		beginTime:    beginTime,
-		cs:           cs,
-		dc:           cs.cc.dopts.dc,
-		statsHandler: sh,
-		trInfo:       trInfo,
-	}
-	defer func() {
-		if retErr != nil {
-			// This attempt is not set in the clientStream, so it's finish won't
-			// be called. Call it here for stats and trace in case they are not
-			// nil.
-			newAttempt.finish(retErr)
-		}
-	}()
-
-	if err := ctx.Err(); err != nil {
-		return toRPCErr(err)
-	}
-
 	if cs.cc.parsedTarget.Scheme == "xds" {
 		// Add extra metadata (metadata that will be added by transport) to context
 		// so the balancer can see them.
@@ -407,16 +412,32 @@ func (cs *clientStream) newAttemptLocked(isTransparent bool) (retErr error) {
 			"content-type", grpcutil.ContentType(cs.callHdr.ContentSubtype),
 		))
 	}
-	t, done, err := cs.cc.getTransport(ctx, cs.callInfo.failFast, cs.callHdr.Method)
+
+	return &csAttempt{
+		ctx:          ctx,
+		beginTime:    beginTime,
+		cs:           cs,
+		dc:           cs.cc.dopts.dc,
+		statsHandler: sh,
+		trInfo:       trInfo,
+	}, nil
+}
+
+func (a *csAttempt) getTransport() error {
+	cs := a.cs
+
+	var err error
+	a.t, a.done, err = cs.cc.getTransport(a.ctx, cs.callInfo.failFast, cs.callHdr.Method)
 	if err != nil {
+		if de, ok := err.(dropError); ok {
+			err = de.error
+			a.drop = true
+		}
 		return err
 	}
-	if trInfo != nil {
-		trInfo.firstLine.SetRemoteAddr(t.RemoteAddr())
+	if a.trInfo != nil {
+		a.trInfo.firstLine.SetRemoteAddr(a.t.RemoteAddr())
 	}
-	newAttempt.t = t
-	newAttempt.done = done
-	cs.attempt = newAttempt
 	return nil
 }

@@ -425,12 +446,21 @@ func (a *csAttempt) newStream() error {
 	cs.callHdr.PreviousAttempts = cs.numRetries
 	s, err := a.t.NewStream(a.ctx, cs.callHdr)
 	if err != nil {
-		// Return without converting to an RPC error so retry code can
-		// inspect.
-		return err
+		nse, ok := err.(*transport.NewStreamError)
+		if !ok {
+			// Unexpected.
+			return err
+		}
+
+		if nse.AllowTransparentRetry {
+			a.allowTransparentRetry = true
+		}
+
+		// Unwrap and convert error.
+		return toRPCErr(nse.Err)
 	}
-	cs.attempt.s = s
-	cs.attempt.p = &parser{r: s}
+	a.s = s
+	a.p = &parser{r: s}
 	return nil
 }

@@ -456,7 +486,7 @@ type clientStream struct {

 	retryThrottler *retryThrottler // The throttler active when the RPC began.

-	binlog *binarylog.MethodLogger // Binary logger, can be nil.
+	binlog binarylog.MethodLogger // Binary logger, can be nil.
 	// serverHeaderBinlogged is a boolean for whether server header has been
 	// logged. Server header will be logged when the first time one of those
 	// happens: stream.Header(), stream.Recv().
@@ -508,6 +538,11 @@ type csAttempt struct {

 	statsHandler stats.Handler
 	beginTime    time.Time
+
+	// set for newStream errors that may be transparently retried
+	allowTransparentRetry bool
+	// set for pick errors that are returned as a status
+	drop bool
 }

 func (cs *clientStream) commitAttemptLocked() {
@@ -527,41 +562,21 @@ func (cs *clientStream) commitAttempt() {
 // shouldRetry returns nil if the RPC should be retried; otherwise it returns
 // the error that should be returned by the operation.  If the RPC should be
 // retried, the bool indicates whether it is being retried transparently.
-func (cs *clientStream) shouldRetry(err error) (bool, error) {
-	if cs.attempt.s == nil {
-		// Error from NewClientStream.
-		nse, ok := err.(*transport.NewStreamError)
-		if !ok {
-			// Unexpected, but assume no I/O was performed and the RPC is not
-			// fatal, so retry indefinitely.
-			return true, nil
-		}
+func (a *csAttempt) shouldRetry(err error) (bool, error) {
+	cs := a.cs

-		// Unwrap and convert error.
-		err = toRPCErr(nse.Err)
-
-		// Never retry DoNotRetry errors, which indicate the RPC should not be
-		// retried due to max header list size violation, etc.
-		if nse.DoNotRetry {
-			return false, err
-		}
-
-		// In the event of a non-IO operation error from NewStream, we never
-		// attempted to write anything to the wire, so we can retry
-		// indefinitely.
-		if !nse.DoNotTransparentRetry {
-			return true, nil
-		}
-	}
-	if cs.finished || cs.committed {
-		// RPC is finished or committed; cannot retry.
+	if cs.finished || cs.committed || a.drop {
+		// RPC is finished or committed or was dropped by the picker; cannot retry.
 		return false, err
 	}
+	if a.s == nil && a.allowTransparentRetry {
+		return true, nil
+	}
 	// Wait for the trailers.
 	unprocessed := false
-	if cs.attempt.s != nil {
-		<-cs.attempt.s.Done()
-		unprocessed = cs.attempt.s.Unprocessed()
+	if a.s != nil {
+		<-a.s.Done()
+		unprocessed = a.s.Unprocessed()
 	}
 	if cs.firstAttempt && unprocessed {
 		// First attempt, stream unprocessed: transparently retry.
@@ -573,14 +588,14 @@ func (cs *clientStream) shouldRetry(err error) (bool, error) {

 	pushback := 0
 	hasPushback := false
-	if cs.attempt.s != nil {
-		if !cs.attempt.s.TrailersOnly() {
+	if a.s != nil {
+		if !a.s.TrailersOnly() {
 			return false, err
 		}

 		// TODO(retry): Move down if the spec changes to not check server pushback
 		// before considering this a failure for throttling.
-		sps := cs.attempt.s.Trailer()["grpc-retry-pushback-ms"]
+		sps := a.s.Trailer()["grpc-retry-pushback-ms"]
 		if len(sps) == 1 {
 			var e error
 			if pushback, e = strconv.Atoi(sps[0]); e != nil || pushback < 0 {
@@ -597,10 +612,10 @@ func (cs *clientStream) shouldRetry(err error) (bool, error) {
 	}

 	var code codes.Code
-	if cs.attempt.s != nil {
-		code = cs.attempt.s.Status().Code()
+	if a.s != nil {
+		code = a.s.Status().Code()
 	} else {
-		code = status.Convert(err).Code()
+		code = status.Code(err)
 	}

 	rp := cs.methodConfig.RetryPolicy
@@ -645,19 +660,24 @@ func (cs *clientStream) shouldRetry(err error) (bool, error) {
 }

 // Returns nil if a retry was performed and succeeded; error otherwise.
-func (cs *clientStream) retryLocked(lastErr error) error {
+func (cs *clientStream) retryLocked(attempt *csAttempt, lastErr error) error {
 	for {
-		cs.attempt.finish(toRPCErr(lastErr))
-		isTransparent, err := cs.shouldRetry(lastErr)
+		attempt.finish(toRPCErr(lastErr))
+		isTransparent, err := attempt.shouldRetry(lastErr)
 		if err != nil {
 			cs.commitAttemptLocked()
 			return err
 		}
 		cs.firstAttempt = false
-		if err := cs.newAttemptLocked(isTransparent); err != nil {
+		attempt, err = cs.newAttemptLocked(isTransparent)
+		if err != nil {
+			// Only returns error if the clientconn is closed or the context of
+			// the stream is canceled.
 			return err
 		}
-		if lastErr = cs.replayBufferLocked(); lastErr == nil {
+		// Note that the first op in the replay buffer always sets cs.attempt
+		// if it is able to pick a transport and create a stream.
+		if lastErr = cs.replayBufferLocked(attempt); lastErr == nil {
 			return nil
 		}
 	}
@@ -667,7 +687,10 @@ func (cs *clientStream) Context() context.Context {
 	cs.commitAttempt()
 	// No need to lock before using attempt, since we know it is committed and
 	// cannot change.
-	return cs.attempt.s.Context()
+	if cs.attempt.s != nil {
+		return cs.attempt.s.Context()
+	}
+	return cs.ctx
 }

 func (cs *clientStream) withRetry(op func(a *csAttempt) error, onSuccess func()) error {
@@ -697,7 +720,7 @@ func (cs *clientStream) withRetry(op func(a *csAttempt) error, onSuccess func())
 			cs.mu.Unlock()
 			return err
 		}
-		if err := cs.retryLocked(err); err != nil {
+		if err := cs.retryLocked(a, err); err != nil {
 			cs.mu.Unlock()
 			return err
 		}
@@ -728,7 +751,7 @@ func (cs *clientStream) Header() (metadata.MD, error) {
 		cs.binlog.Log(logEntry)
 		cs.serverHeaderBinlogged = true
 	}
-	return m, err
+	return m, nil
 }

 func (cs *clientStream) Trailer() metadata.MD {
@@ -746,10 +769,9 @@ func (cs *clientStream) Trailer() metadata.MD {
 	return cs.attempt.s.Trailer()
 }

-func (cs *clientStream) replayBufferLocked() error {
-	a := cs.attempt
+func (cs *clientStream) replayBufferLocked(attempt *csAttempt) error {
 	for _, f := range cs.buffer {
-		if err := f(a); err != nil {
+		if err := f(attempt); err != nil {
 			return err
 		}
 	}
@@ -797,22 +819,17 @@ func (cs *clientStream) SendMsg(m interface{}) (err error) {
 	if len(payload) > *cs.callInfo.maxSendMessageSize {
 		return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(payload), *cs.callInfo.maxSendMessageSize)
 	}
-	msgBytes := data // Store the pointer before setting to nil. For binary logging.
 	op := func(a *csAttempt) error {
-		err := a.sendMsg(m, hdr, payload, data)
-		// nil out the message and uncomp when replaying; they are only needed for
-		// stats which is disabled for subsequent attempts.
-		m, data = nil, nil
-		return err
+		return a.sendMsg(m, hdr, payload, data)
 	}
 	err = cs.withRetry(op, func() { cs.bufferForRetryLocked(len(hdr)+len(payload), op) })
 	if cs.binlog != nil && err == nil {
 		cs.binlog.Log(&binarylog.ClientMessage{
 			OnClientSide: true,
-			Message:      msgBytes,
+			Message:      data,
 		})
 	}
-	return
+	return err
 }

 func (cs *clientStream) RecvMsg(m interface{}) error {
@@ -1364,8 +1381,10 @@ func (as *addrConnStream) finish(err error) {

 // ServerStream defines the server-side behavior of a streaming RPC.
 //
-// All errors returned from ServerStream methods are compatible with the
-// status package.
+// Errors returned from ServerStream methods are compatible with the status
+// package.  However, the status code will often not match the RPC status as
+// seen by the client application, and therefore, should not be relied upon for
+// this purpose.
 type ServerStream interface {
 	// SetHeader sets the header metadata. It may be called multiple times.
 	// When call multiple times, all the provided metadata will be merged.
@@ -1428,7 +1447,7 @@ type serverStream struct {

 	statsHandler stats.Handler

-	binlog *binarylog.MethodLogger
+	binlog binarylog.MethodLogger
 	// serverHeaderBinlogged indicates whether server header has been logged. It
 	// will happen when one of the following two happens: stream.SendHeader(),
 	// stream.Send().
@@ -1448,11 +1467,20 @@ func (ss *serverStream) SetHeader(md metadata.MD) error {
 	if md.Len() == 0 {
 		return nil
 	}
+	err := imetadata.Validate(md)
+	if err != nil {
+		return status.Error(codes.Internal, err.Error())
+	}
 	return ss.s.SetHeader(md)
 }

 func (ss *serverStream) SendHeader(md metadata.MD) error {
-	err := ss.t.WriteHeader(ss.s, md)
+	err := imetadata.Validate(md)
+	if err != nil {
+		return status.Error(codes.Internal, err.Error())
+	}
+
+	err = ss.t.WriteHeader(ss.s, md)
 	if ss.binlog != nil && !ss.serverHeaderBinlogged {
 		h, _ := ss.s.Header()
 		ss.binlog.Log(&binarylog.ServerHeader{
@@ -1467,6 +1495,9 @@ func (ss *serverStream) SetTrailer(md metadata.MD) {
 	if md.Len() == 0 {
 		return
 	}
+	if err := imetadata.Validate(md); err != nil {
+		logger.Errorf("stream: failed to validate md when setting trailer, err: %v", err)
+	}
 	ss.s.SetTrailer(md)
 }

@@ -19,4 +19,4 @@
 package grpc

 // Version is the current grpc version.
-const Version = "1.45.0"
+const Version = "1.47.0"
@@ -84,6 +84,9 @@ github.com/coredns/coredns/plugin/pkg/transport
 github.com/coredns/coredns/plugin/pkg/uniq
 github.com/coredns/coredns/plugin/test
 github.com/coredns/coredns/request
+# github.com/coreos/go-oidc/v3 v3.4.0
+## explicit; go 1.14
+github.com/coreos/go-oidc/v3/oidc
 # github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
 ## explicit
 github.com/coreos/go-systemd/daemon
@@ -141,6 +144,7 @@ github.com/gobwas/ws/wsutil
 github.com/golang-collections/collections/queue
 # github.com/golang/protobuf v1.5.2
 ## explicit; go 1.9
+github.com/golang/protobuf/jsonpb
 github.com/golang/protobuf/proto
 github.com/golang/protobuf/ptypes
 github.com/golang/protobuf/ptypes/any
@@ -386,11 +390,11 @@ golang.org/x/net/ipv6
 golang.org/x/net/proxy
 golang.org/x/net/trace
 golang.org/x/net/websocket
-# golang.org/x/oauth2 v0.0.0-20211104180415-d3ed0bb246c8
-## explicit; go 1.11
+# golang.org/x/oauth2 v0.0.0-20220822191816-0ebed06d0094
+## explicit; go 1.17
 golang.org/x/oauth2
 golang.org/x/oauth2/internal
-# golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
+# golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f
 ## explicit
 golang.org/x/sync/errgroup
 # golang.org/x/sys v0.0.0-20220808155132-1c4a2a72c664
@@ -434,8 +438,8 @@ golang.org/x/tools/internal/imports
 golang.org/x/tools/internal/packagesinternal
 golang.org/x/tools/internal/typeparams
 golang.org/x/tools/internal/typesinternal
-# golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1
-## explicit; go 1.11
+# golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f
+## explicit; go 1.17
 golang.org/x/xerrors
 golang.org/x/xerrors/internal
 # google.golang.org/appengine v1.6.7
@@ -447,12 +451,12 @@ google.golang.org/appengine/internal/log
 google.golang.org/appengine/internal/remote_api
 google.golang.org/appengine/internal/urlfetch
 google.golang.org/appengine/urlfetch
-# google.golang.org/genproto v0.0.0-20211223182754-3ac035c7e7cb
-## explicit; go 1.11
+# google.golang.org/genproto v0.0.0-20220616135557-88e70c0c3a90
+## explicit; go 1.15
 google.golang.org/genproto/googleapis/api/httpbody
 google.golang.org/genproto/googleapis/rpc/status
 google.golang.org/genproto/protobuf/field_mask
-# google.golang.org/grpc v1.45.0
+# google.golang.org/grpc v1.47.0
 ## explicit; go 1.14
 google.golang.org/grpc
 google.golang.org/grpc/attributes
@@ -462,6 +466,7 @@ google.golang.org/grpc/balancer/base
 google.golang.org/grpc/balancer/grpclb/state
 google.golang.org/grpc/balancer/roundrobin
 google.golang.org/grpc/binarylog/grpc_binarylog_v1
+google.golang.org/grpc/channelz
 google.golang.org/grpc/codes
 google.golang.org/grpc/connectivity
 google.golang.org/grpc/credentials
@@ -471,6 +476,7 @@ google.golang.org/grpc/encoding/proto
 google.golang.org/grpc/grpclog
 google.golang.org/grpc/internal
 google.golang.org/grpc/internal/backoff
+google.golang.org/grpc/internal/balancer/gracefulswitch
 google.golang.org/grpc/internal/balancerload
 google.golang.org/grpc/internal/binarylog
 google.golang.org/grpc/internal/buffer
@@ -482,6 +488,7 @@ google.golang.org/grpc/internal/grpcrand
 google.golang.org/grpc/internal/grpcsync
 google.golang.org/grpc/internal/grpcutil
 google.golang.org/grpc/internal/metadata
+google.golang.org/grpc/internal/pretty
 google.golang.org/grpc/internal/resolver
 google.golang.org/grpc/internal/resolver/dns
 google.golang.org/grpc/internal/resolver/passthrough
Author	SHA1	Message	Date
João Oliveirinha	f81d35447e	Release 2022.10.0	2022-10-03 09:55:15 +01:00
cthuang	49438f30f5	TUN-6813: Only proxy ICMP packets when warp-routing is enabled	2022-09-30 19:08:12 +01:00
cthuang	eacc8c648d	TUN-6812: Drop IP packets if ICMP proxy is not initialized	2022-09-30 14:10:32 +00:00
Sudarsan Reddy	5b30925773	TUN-6755: Remove unused publish functions We no longer need the functions that publish deb and rpm to the old pkg.cloudflare.com backed since we now send them to R2.	2022-09-30 10:28:28 +01:00
Devin Carr	d7fb18be22	TUN-6810: Add component test for post-quantum	2022-09-29 09:22:43 -07:00
cthuang	cbf8c71fab	TUN-6716: Document limitation of Windows ICMP proxy	2022-09-29 14:51:53 +01:00
cthuang	870193c064	TUN-6811: Ping group range should be parsed as int32	2022-09-29 12:59:38 +01:00
cthuang	fdddd86380	TUN-6715: Provide suggestion to add cloudflared to ping_group_range if it failed to open ICMP socket	2022-09-28 17:30:13 +01:00
Devin Carr	b3e26420c0	TUN-6801: Add punycode alternatives for ingress rules	2022-09-26 17:59:45 +00:00
cthuang	be0305ec58	TUN-6741: ICMP proxy tries to listen on specific IPv4 & IPv6 when possible If it cannot determine the correct interface IP, it will fallback to all interfaces. This commit also introduces the icmpv4-src and icmpv6-src flags	2022-09-26 11:37:08 +01:00
cthuang	3449ea35f2	TUN-6791: Calculate ICMPv6 checksum	2022-09-22 15:18:53 +00:00
Sudarsan Reddy	7f487c2651	TUN-6775: Add middleware.Handler verification to ProxyHTTP ProxyHTTP now processes middleware Handler before executing the request. A chain of handlers is now executed and appropriate response status codes are sent.	2022-09-22 15:11:59 +01:00
Sudarsan Reddy	9bb7628fbc	TUN-6772: Add a JWT Validator as an ingress verifier This adds a new verifier interface that can be attached to ingress.Rule. This would act as a middleware layer that gets executed at the start of proxy.ProxyHTTP. A jwt validator implementation for this verifier is also provided. The validator downloads the public key from the access teams endpoint and uses it to verify the JWT sent to cloudflared with the audtag (clientID) information provided in the config.	2022-09-22 14:44:03 +01:00
Sudarsan Reddy	eb36716ba4	TUN-6774: Validate OriginRequest.Access to add Ingress.Middleware We take advantage of the JWTValidator middleware and attach it to an ingress rule based on Access configurations. We attach the Validator directly to the ingress rules because we want to take advantage of caching and token revert/handling that comes with go-oidc.	2022-09-22 14:44:03 +01:00
Sudarsan Reddy	5d6b0642db	TUN-6772: Add a JWT Validator as an ingress verifier This adds a new verifier interface that can be attached to ingress.Rule. This would act as a middleware layer that gets executed at the start of proxy.ProxyHTTP. A jwt validator implementation for this verifier is also provided. The validator downloads the public key from the access teams endpoint and uses it to verify the JWT sent to cloudflared with the audtag (clientID) information provided in the config.	2022-09-22 14:44:03 +01:00
Sudarsan Reddy	462d2f87df	TUN-6774: Validate OriginRequest.Access to add Ingress.Middleware We take advantage of the JWTValidator middleware and attach it to an ingress rule based on Access configurations. We attach the Validator directly to the ingress rules because we want to take advantage of caching and token revert/handling that comes with go-oidc.	2022-09-22 13:43:15 +00:00
Nuno Diegues	0aa21f302e	TUN-6792: Fix brew core release by not auditing the formula	2022-09-22 11:58:17 +01:00
Sudarsan Reddy	de07da02cd	TUN-6772: Add a JWT Validator as an ingress verifier This adds a new verifier interface that can be attached to ingress.Rule. This would act as a middleware layer that gets executed at the start of proxy.ProxyHTTP. A jwt validator implementation for this verifier is also provided. The validator downloads the public key from the access teams endpoint and uses it to verify the JWT sent to cloudflared with the audtag (clientID) information provided in the config.	2022-09-22 08:42:25 +00:00