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#!/usr/bin/perl
#
# see http://search.cpan.org/~atrak/NetPacket-0.04/
#use strict;
BEGIN {
push @INC,"perl";
push @INC,"build/perl";
push @INC,"NetPacket-0.04";
};
use nfqueue;
use NetPacket::IP qw(IP_PROTO_TCP);
use NetPacket::TCP;
use Socket qw(AF_INET AF_INET6);
my $q;
sub cleanup()
{
print "unbind\n";
$q->unbind(AF_INET);
print "close\n";
$q->close();
}
sub cb()
{
my ($dummy,$payload) = @_;
print "Perl callback called!\n";
print "dummy is $dummy\n" if $dummy;
if ($payload) {
print "len: " . $payload->get_length() . "\n";
my $ip_obj = NetPacket::IP->decode($payload->get_data());
print $ip_obj, "\n";
print("$ip_obj->{src_ip} => $ip_obj->{dest_ip} $ip_obj->{proto}\n");
print "Id: " . $payload->swig_id_get() . "\n";
if($ip_obj->{proto} == IP_PROTO_TCP) {
# decode the TCP header
my $tcp_obj = NetPacket::TCP->decode($ip_obj->{data});
print "TCP src_port: $tcp_obj->{src_port}\n";
print "TCP dst_port: $tcp_obj->{dest_port}\n";
print "TCP flags : $tcp_obj->{flags}\n";
print "TCP data : $tcp_obj->{data}\n";
if ($tcp_obj->{flags} & NetPacket::TCP::PSH &&
length($tcp_obj->{data})) {
print "data is defined\n";
#$tcp_obj->{data} = 'gruik';
$tcp_obj->{data} =~ s/love/hate/m;
print "**********\n";
print $tcp_obj->{data};
print "**********\n";
}
# try modifying the packet
#$ip_obj->{src_ip} = "1.2.3.4";
#$tcp_obj->{src_port} = 42;
#$ip_obj->{dest_ip} = "213.186.33.19";
$tcp_obj->{checksum} = 0;
$ip_obj->{checksum} = 0;
$ip_obj->{data} = $tcp_obj->encode($ip_obj);
my $modified_payload = $ip_obj->encode();
my $ip2 = NetPacket::IP->decode($modified_payload);
print("$ip2->{src_ip} => $ip2->{dest_ip} $ip2->{proto}\n");
my $tcp2 = NetPacket::TCP->decode($ip2->{data});
print "TCP src_port: $tcp2->{src_port}\n";
print "TCP dst_port: $tcp2->{dest_port}\n";
print "data length: ", length($modified_payload), "\n";
my $ret = $payload->set_verdict_modified($nfqueue::NF_ACCEPT,$modified_payload,length($modified_payload));
print "ret: $ret\n";
return;
}
$payload->set_verdict($nfqueue::NF_ACCEPT);
return;
}
$payload->set_verdict($nfqueue::NF_ACCEPT);
}
$q = new nfqueue::queue();
print "open\n";
$q->open();
print "bind\n";
$q->bind(AF_INET);
$SIG{INT} = "cleanup";
#print "set callback, wrong argument type (should fail)\n";
#$q->set_callback("blah");
print "setting callback\n";
$q->set_callback(\&cb);
print "creating queue\n";
$q->create_queue(0);
print "trying to run\n";
$q->try_run();
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