One Hat Cyber Team

View File Name : RBLClient.pm

package Net::RBLClient;
use strict;
use IO::Socket;
use Time::HiRes qw( time );
use Net::DNS::Packet;

use vars qw( $VERSION $ip_pat );
$ip_pat = qr(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3});
$VERSION = '0.4';

sub new {
    my($class, %args) = @_;
    my $self = {
        lists       => [ lists() ],
        query_txt   => 0,
        max_time    => 8,
        timeout     => 1,
        max_hits    => 1000,
        max_replies => 1000,
        udp_maxlen  => 4000,
        server      => 'resolv.conf',
    };
    bless $self, $class;
    foreach my $key(keys %args) {
        defined($self->{ $key })
            or die "Invalid key: $key";
        $self->{ $key } = $args{ $key }; 
    }
    if($self->{ server } eq 'resolv.conf') {
        local *F;
        open F, '/etc/resolv.conf'
            or die "Can't open resolv.conf: $!";
        local $/;
        my $resolv = <F>;
        if($resolv =~ /^nameserver\s+($ip_pat)/m) {
            $self->{ server } = $1;
        }
        else {
            die "No nameserver found in resolv.conf; specify one in constructor";
        }
    }
    $self;
}

sub lookup {
    my($self, $target_ip) = @_;
    $target_ip =~ /^$ip_pat$/
        or die "Invalid ip: '$target_ip' - must be dotted quad";
    my $start_time = time;
    my $qip = join '.', reverse(split /\./, $target_ip);
    my $deadline = time + $self->{ max_time };

    my $sock = IO::Socket::INET->new(
        Proto     => 'udp',
        PeerPort  => 53,
        PeerAddr  => $self->{ server },
    ) or die "Failed to create UDP client";

    if ( $self->{ query_txt } ) {
        foreach my $list(@{ $self->{ lists } }) {
            my($msg_a, $msg_t) = mk_packet($qip, $list);
            foreach ($msg_a, $msg_t) { $sock->send($_) or die "send: $!" }
        }
    }
    else {
        foreach my $list(@{ $self->{ lists } }) {
            my $msg = mk_packet($qip, $list);
            $sock->send($msg) || die "send: $!";
        }
    }
    my $dur = time - $start_time;

    $self->{ results } = {};
    $self->{ txt } = {};

    # Keep recv'ing packets until one of the exit conditions is met:

    my $needed = @{ $self->{ lists } }; # how many packets needed back
    $needed <<= 1 if $self->{ query_txt };
    my $hits = my $replies = 0;

    while($needed && time < $deadline) {
        my $msg = '';
        eval {
            local $SIG{ ALRM } = sub { die "alarm time out" };
            alarm $self->{ timeout };
            $sock->recv($msg, $self->{ udp_maxlen })  || die "recv: $!";
            alarm 0;
            1; # eval was OK
        };
        if($msg) {
            my ($domain, $res, $type) = decode_packet($msg);
            if ( defined $type && $type eq 'TXT' ) {
                $self->{ txt }{ $domain } = $res
            }
            elsif ($res) {
                $replies ++;
                $hits ++ if $res;
                $self->{ results }{ $domain } = $res;
                return 1 if    $hits >= $self->{ max_hits } ||
                            $replies >= $self->{ max_replies };
            }
            $needed --;
        }
    }
    1;
}

sub listed_by {
    my $self = shift;
    sort keys %{ $self->{ results } };
}

sub listed_hash {
    my $self = shift;
    %{ $self->{ results } };
}

sub txt_hash {
    my $self = shift;
    warn <<_ unless $self->{ query_txt };
Without query_txt turned on, you won't get any results from ->txt_hash().
_
    if (wantarray) { %{ $self->{ txt } } }
    else { $self->{ txt } }
}

# End methods - begin internal functions

sub mk_packet {
    # pass me a REVERSED dotted quad ip (qip) and a blocklist domain
    my($qip, $list) = @_;
    my($packet, $error) = new Net::DNS::Packet my $fqdn = "$qip.$list", 'A';
    die "Cannot build DNS query for $fqdn, type A: $error" unless $packet;
    $packet->header->rd(1);
    return $packet->data unless wantarray;
    (my $txt_packet, $error) = new Net::DNS::Packet $fqdn, 'TXT', 'IN';
    die "Cannot build DNS query for $fqdn, type TXT: $error" unless $txt_packet;
    $txt_packet->header->rd(1);
    $packet->data, $txt_packet->data;
}

sub decode_packet {
    # takes a raw DNS response packet
    # returns domain, response
    my $data = shift;
    my $packet = Net::DNS::Packet->new(\$data);
    my @answer = $packet->answer;

    {
        my($res, $domain, $type);
        foreach my $answer (@answer) {
            {
                # removed $answer->answerfrom because it caused an error
                # with some types of answers

                my $name = lc $answer->name;
                warn "Packet contained answers to different domains ($domain != $name)"
                  if defined $domain && $name ne $domain;
                $domain = $name;
            }
            $domain =~ s/^\d+\.\d+\.\d+\.\d+\.//;
            $type = $answer->type;
            $res = $type eq 'A'     ? inet_ntoa($answer->rdata)  :
                   $type eq 'CNAME' ?   cleanup($answer->rdata)  :
                   $type eq 'TXT'   ? (defined $res && "$res; ")
                                      . $answer->txtdata         :
                   '?';
            last unless $type eq 'TXT';
        }
        return $domain, $res, $type if defined $res;
    }
    
    # OK, there were no answers -
    # need to determine which domain
    # sent the packet.

    my @question = $packet->question;
    foreach my $question(@question) {
        my $domain = $question->qname;
        $domain =~ s/^\d+\.\d+\.\d+\.\d+\.//;
        return($domain, undef);
    }
}

sub cleanup {
    # remove control chars and stuff
    $_[ 0 ] =~ tr/a-zA-Z0-9./ /cs;;
    $_[ 0 ];
}

# lists removed due to osirusoft outage:

        # spews.relays.osirusoft.com
        # spamsites.relays.osirusoft.com
        # spamhaus.relays.osirusoft.com
        # socks.relays.osirusoft.com
        # relays.osirusoft.com
        # proxy.relays.osirusoft.com
        # inputs.relays.osirusoft.com
        # dialups.relays.osirusoft.com
        # blocktest.relays.osirusoft.com

sub lists {
    qw(
        badconf.rhsbl.sorbs.net
        bl.reynolds.net.au
        bl.spamcop.net
        blackholes.brainerd.net
        blackholes.five-ten-sg.com
        blackholes.intersil.net
        blackholes.wirehub.net
        block.blars.org
        block.dnsbl.sorbs.net
        dev.null.dk
        dnsbl.njabl.org
        dul.dnsbl.sorbs.net
        dynablock.wirehub.net
        flowgoaway.com
        http.dnsbl.sorbs.net
        http.opm.blitzed.org
        korea.services.net
        list.dsbl.org
        misc.dnsbl.sorbs.net
        multihop.dsbl.org
        no-more-funn.moensted.dk
        nomail.rhsbl.sorbs.net
        opm.blitzed.org
        orbs.dorkslayers.com
        psbl.surriel.com
        relays.dorkslayers.com
        relays.visi.com
        smtp.dnsbl.sorbs.net
        socks.dnsbl.sorbs.net
        socks.opm.blitzed.org
        spam.dnsbl.sorbs.net
        spamguard.leadmon.net
        spammers.v6net.org
        spamsources.fabel.dk
        spews.bl.reynolds.net.au
        unconfirmed.dsbl.org
        web.dnsbl.sorbs.net
        work.drbl.croco.net
        zombie.dnsbl.sorbs.net
        ztl.dorkslayers.com
    );
}
1;

__END__

=head1 NAME

Net::RBLClient - Queries multiple Realtime Blackhole Lists in parallel

=head1 SYNOPSIS

    use Net::RBLClient;
    my $rbl = Net::RBLClient->new;
    $rbl->lookup('211.101.236.160');
    my @listed_by = $rbl->listed_by;

=head1 DESCRIPTION

This module is used to discover what RBL's are listing a particular IP
address.  It parallelizes requests for fast response.

An RBL, or Realtime Blackhole List, is a list of IP addresses meeting some
criteria such as involvement in Unsolicited Bulk Email.  Each RBL has
its own criteria for addition and removal of addresses.  If you want to
block email or other traffic to/from your network based on one or more
RBL's, you should carefully study the behavior of those RBL's before and
during such blocking.

=head1 CONSTRUCTOR

=over 4

=item new( [ARGS] )

Takes an optional hash of arguments:

=over 4

=item lists

An arraref of (sub)domains representing RBLs.  In other words, each element
in the array is a string similar to 'relays.somerbl.org'.  Use this if
you want to query a specific list of RBL's - if this argument is omitted,
a large list of RBL's is queried.

=item query_txt

Set this to true if you want Net::RBLClient to also query for TXT records,
in which many RBL's store additional information about the reason for
including an IP address or links to pages that contain such information.
You can then retrieve these information using the L</txt_hash()> method.

=item max_time

The maximum time in seconds that the lookup function should take.  In fact,
the function can take up to C<max_time + timeout> seconds.  Max_time need
not be integer.  Of course, if the lookup returns due to max_time, some
DNS replies will be missed.

Default: 8 seconds.

=item timeout

The maximum time in seconds spent awaiting each DNS reply packet.  The
only reason to change this is if C<max_time> is decreased to a small value.

Default: 1 second.

=item max_hits

A hit is an affirmative response, stating that the IP address is on a certain
list.  If C<max_hits> hits are received, C<lookup()> returns immediately.
This lets the calling program save time.

Default: 1000 (effectively out of the picture).

=item max_replies

A reply from an RBL could be affirmative or negative.  Either way, it counts
towards C<max_replies>.  C<Lookup()> returns when C<max_replies> replies
have been received.

=item udp_maxlen

The maximum number of bytes read from a DNS reply packet.  There's probably
no reason to change this.

Default: 4000

=item server

The local nameserver to use for all queries.  Should be either a resolvable
hostname or a dotted quad IP address.

By default, the first nameserver in /etc/resolv.conf will be used.

=back

=back

=head1 METHODS

=over 4

=item lookup( IPADDR )

Lookup one IP address on all RBL's previously defined.  The IP address
must be expressed in dotted quad notation, like '1.2.3.4'.  C<Lookup()>
returns 1.

=item listed_by()

Return an array of RBL's which block the specified IP.  The RBL's are
indicated via the (sub)domain used for DNS query.  The calling program
must first call C<lookup()>.

=item listed_hash()

Return a hash whose keys are the RBL's which block the specified IP,
represented as in C<listed_by()>.  If the RBL returned an A record,
the value for that key will be the IP address in the A record -
typically 127.0.0.1 - 127.0.0.4.  If the RBL returned a CNAME, the
value will be the hostname, typically used for a comment on why the
IP address is listed.

=item txt_hash()

Return a hash (or a reference to that hash if called in a scalar
context) whose keys are the RBL's which block the specified IP,
represented as in C<listed_by()>.  If the RBL returned TXT records
containing additional information, the value will contain this
information (several TXT records from one RBL will be joined by
semicolons, but this should not happen), if not, it will be
L<undef|perlfunc/undef>.

=back

=head1 AUTHOR

Asher Blum E<lt>F<asher@wildspark.com>E<gt>

=head1 CREDITS

Martin H. Sluka E<lt>F<martin@sluka.de>E<gt>

=head1 COPYRIGHT

Copyright (C) 2002 Asher Blum.  All rights reserved.
This code is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.

=cut

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