# Volatility
# Copyright (C) 2007-2013 Volatility Foundation
#
# This file is part of Volatility.
#
# Volatility is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License Version 2 as
# published by the Free Software Foundation.  You may not use, modify or
# distribute this program under any other version of the GNU General
# Public License.
#
# Volatility is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Volatility.  If not, see <http://www.gnu.org/licenses/>.
#

"""
@author:       Andrew Case
@license:      GNU General Public License 2.0
@contact:      atcuno@gmail.com
@organization: 
"""

import volatility.obj as obj
import volatility.debug as debug
import volatility.plugins.linux.common as linux_common
import socket

class linux_route_cache(linux_common.AbstractLinuxCommand):
    """ Recovers the routing cache from memory """

    def __init__(self, config, *args, **kwargs):
        linux_common.AbstractLinuxCommand.__init__(self, config, *args, **kwargs)
        config.add_option('RESOLVE', short_option = 'R', default = None, action='count',
                          help = 'Resolve DNS names of remote IP addresses')

    def calculate(self):
        linux_common.set_plugin_members(self)

        mask_addr = self.addr_space.profile.get_symbol("rt_hash_mask")
        
        if mask_addr == None:
            debug.error("This plugin does not support this profile. The Linux routing cache was deleted in 3.6.x. See: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=89aef8921bfbac22f00e04f8450f6e447db13e42")

        mask = obj.Object("unsigned int", offset = mask_addr, vm = self.addr_space)
        rt_pointer = obj.Object("Pointer", offset = self.addr_space.profile.get_symbol("rt_hash_table"), vm = self.addr_space)
        rt_hash_table = obj.Object(theType = "Array", offset = rt_pointer, vm = self.addr_space, targetType = "rt_hash_bucket", count = mask)

        # rt_do_flush / rt_cache_seq_show
        for i in range(mask):

            rth = rt_hash_table[i].chain

            if not rth:
                continue

            while rth:
 
                # FIXME: Consider using kernel version metadata rather than checking hasattr
                if hasattr(rth, 'u'):
                    dst = rth.u.dst
                    nxt = rth.u.dst.rt_next
                else:
                    dst = rth.dst
                    nxt = rth.dst.rt_next

                if dst.dev:
                    name = dst.dev.name
                else:
                    name = "*"

                dest = rth.rt_dst
                gw = rth.rt_gateway

                yield (name, dest, gw)

                rth = nxt

    def render_text(self, outfd, data):
        if self._config.RESOLVE:
            self.table_header(outfd, [("Interface", "16"),
                                  ("Destination", "20"),
                                  ("Dest Name", "30"), 
                                  ("Gateway", "")])
        else:
            self.table_header(outfd, [("Interface", "16"),
                                  ("Destination", "20"),
                                  ("Gateway", "")])
   
        for (name, dest, gw) in data:
            if self._config.RESOLVE:
                
                host = str(dest.cast("IpAddress"))
                try:
                    host = socket.gethostbyaddr(host)
                    host = host[0]
                except socket.herror:
                    host = ""
                except socket.gaierror:
                    host = ""
                
                self.table_row(outfd, name, dest.cast("IpAddress"), host, gw.cast("IpAddress"))
            else:        
                self.table_row(outfd, name, dest.cast("IpAddress"), gw.cast("IpAddress"))