#!/usr/bin/perl -sw-

# ----------------------------------------------------------
# 	       listen for stub notifications
# 
# 		       Meng Weng Wong
# $Id$
# runs as a daemon; writes stub notifications to a text file that contains stub notifications.
# 
# in the future, write stub notifications to a database, and avoid attacks by uniq'ing the stub url.
# 
# usage:
# 
# arguments:
# 
# flags:
# 
# input:
# 
# output:
# 
# license: GPL
# 
# must run as root to bind to port 252.
# meng selected port 252 as the stub listener, but that's really determined by the _stub._udp SRV record.
# ----------------------------------------------------------

# ----------------------------------------------------------
# 		       initialization
# ----------------------------------------------------------

# ----------------------------------------------------------
# 	 no user-serviceable parts below this line
# ----------------------------------------------------------

use strict;
use vars qw($port $ip $outputdir);
use Socket;
use File::Path;
my $MAXLEN = 4096;

my $NOTIFROOT = "/home/mengwong/stubmail/stubs";

use IO::Socket::INET;
use Convert::Bencode qw(bencode bdecode);

my $MySocket = new IO::Socket::INET->new(Proto=>'udp',
					 LocalPort=>252) or die "unable to bind.\n";;

$> = $< = getpwnam("mengwong");

my $text;

$|++;

while ($MySocket->recv($text, $MAXLEN)) {
    my($port, $ipaddr) = sockaddr_in($MySocket->peername);
    $ipaddr = inet_ntoa($ipaddr);

    print join "\t", (time,
		      scalar localtime,
		      "raw: $text\n");

    my $decoded = bdecode($text);

    use Data::Dumper; 
    my $logline = join ("\t", time,
			scalar(localtime),
			join ("; ",
			      "client_ip=$ipaddr",
			      "port=$port",
			      map { "$_=$decoded->{$_}" } sort keys %$decoded)
			) . "\n";
    print $logline;

    # 1144627144      Sun Apr  9 19:59:04 2006        raw: d1:r30:mengwong@rssemail.mailzone.com1:s18:mengwong@pobox.com1:u130:http://blizzard.pobox.com/~mengwong/stubmail/simple_format_1.cgi/24475cfe2f71a969aefc33c33a96db77/c51a61183fee369e7e12d2542906c635e
    # 1144627144      Sun Apr  9 19:59:04 2006        client_ip=209.2.32.37; port=52653; r=mengwong@rssemail.mailzone.com; s=mengwong@pobox.com; u=http://blizzard.pobox.com/~mengwong/stubmail/simple_format_1.cgi/24475cfe2f71a969aefc33c33a96db77/c51a61183fee369e7e12d2542906c635

    my $receiver_notification_filename = $decoded->{r};
    $receiver_notification_filename =~ s/\///g;

    my $sender_as_filename = $decoded->{s};
    $sender_as_filename =~ s/\///g;

    # all kinds of taint problems ... maybe we don't want to use the actual filenames provided.
    ($receiver_notification_filename) = ($receiver_notification_filename =~ /([-\@\w.]+)/);
    ($sender_as_filename) = ($sender_as_filename =~ /([-\@\w.]+)/);

    my $yyyy = sprintf "%04d", (localtime)[5] + 1900;
    my $mm   = sprintf "%02d", (localtime)[4] + 1;
    my $dd   = sprintf "%02d", (localtime)[3];

    eval { mkpath(["$NOTIFROOT/$receiver_notification_filename/$yyyy/$mm/$dd"], 0, 0777); };
    if (not $@) {
	if (open NOTIFICATION, ">> $NOTIFROOT/$receiver_notification_filename/$yyyy/$mm/$dd/$sender_as_filename") {
	    print NOTIFICATION "url = $decoded->{u}\n";
	    print NOTIFICATION "sender = $decoded->{s}\n";
	    print NOTIFICATION "receiver = $decoded->{r}\n";
	    print NOTIFICATION "time = "      . time        . "\n";
	    print NOTIFICATION "localtime = " . localtime() . "\n";
	    print NOTIFICATION "client_ip = " . $ipaddr     . "\n";
	    print NOTIFICATION "port = "      . $port       . "\n";
	    print NOTIFICATION "log = $logline";
	    print NOTIFICATION "\n";
	    close NOTIFICATION;
	}
    }
    else {
	die "$@";
    }

}


# ----------------------------------------------------------
# 		       chunks of text
# ----------------------------------------------------------

# ----------------------------------------------------------
#			    main
# ----------------------------------------------------------

# ----------------------------------------------------------
# 			 functions
# ----------------------------------------------------------

# ----------------------------------------------------------
# 		     format statements
# ----------------------------------------------------------