#!/usr/bin/perl

# This script parses mail sent to spam trap addresses and adds the IP
# address from the last hop to the blocklist. The headers are saved
# to check back on later. I can also pipe messages through it from mutt.

# The received header checks for connecting IP address assume that
# qmail is being used and that there are no local relays or MXs.

use CDB_File;

$LOCK_SH = 1;
$LOCK_EX = 2;
$LOCK_NB = 4;
$LOCK_UN = 8;

umask 022;

chdir '/var/www/html/robot';

$header = '';
$ip = '';
while (<STDIN>) {
  last if m/^$/;
  $header .= $_;
  if ($ip eq '' && m/^received:.*\((\d+\.\d+\.\d+\.\d+)\)\n$/i) {
    $ip = $1;
  }
}

while (<STDIN>) {};

exit(0) if $ENV{'SENDER'} eq '';
exit(0) unless $ip != '';
exit(0) unless $ip !~ '^127\.';

# See if this IP was flagged already.
$new = 1;
$new = 0 if -e "ip1/$ip";

if (!open(IP,">ip1/$ip")) {
  exit(0);
}
# Save message headers for later reference.
print IP "$header";
close(IP);

# If the IP address isn't new we don't need to rebuild the database.
exit(0) unless $new;

# If some other process is already waiting to do an update, no need for us
# to also wait.
if (!open(WAITLOCK, 'waitlock')) {
  exit(0);
}
if (($t = flock(WAITLOCK, $LOCK_EX | $LOCK_NB)) == 0) {
  exit(0);
}

# Wait until any running update has been completed to avoid wasted effort.
if (!open(BASELOCK, 'baselock')) {
print "Unable to open base lock\n";
  exit(0);
}
if (($t = flock(BASELOCK, $LOCK_EX)) == 0) {
  exit(0);
}

# Once we start, free up the wait lock.
flock(WAITLOCK, $LOCK_UN);

# Use a format compatible with rbldns.
opendir(IP, 'ip1');
while ($ip = readdir(IP)) {
  if ($ip =~ m/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/) {
    $key = pack 'CCCCC', $1, $2, $3, $4, 32;
    $ip{$key} = '';
  }
  elsif ($ip =~ m/^(\d+)\.(\d+)\.(\d+)$/) {
    $key = pack 'CCCCC', $1, $2, $3, 0, 24;
    $ip{$key} = '';
  }
  elsif ($ip =~ m/^(\d+)\.(\d+)$/) {
    $key = pack 'CCCCC', $1, $2, 0, 0, 16;
    $ip{$key} = '';
  }
}
$ip{''} = (pack 'CCCC', 127, 0, 0, 10) . 'Spam block';

CDB_File::create %ip, 'data1/data.cdb', "data1/data.cdb.$$";