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package MasterServer::UDP::BeaconCatcher;
use strict;
use warnings;
use AnyEvent::Handle::UDP;
use Socket qw(sockaddr_in inet_ntoa);
use Exporter 'import';
our @EXPORT = qw| beacon_catcher on_beacon_receive|;
##
## Receive UDP beacons according the \heartbeat\7778\gamename\ut\ format
## where "ut" depicts the game and 7778 the query port of the game.
sub beacon_catcher {
my $self = shift;
# module startup log
$self->log("load","Loading UDP Beacon Catcher.");
# UDP server
my $udp_server;
$udp_server = AnyEvent::Handle::UDP->new(
# Bind to this host and use the port specified in the config file
bind => ['0.0.0.0', $self->{beacon_port}],
# when datagrams are received
on_recv => sub {$self->on_beacon_receive(@_)},
);
# display that the server is up and listening for beacons
$self->log("info", "Listening for UT Beacons on port $self->{beacon_port}.");
# allow object to exist beyond this scope. Objects have ambitions too.
return $udp_server;
}
## process (new) beacons
sub on_beacon_receive {
# $self, beacon address, handle, packed client address
my ($self, $b, $udp, $pa) = @_;
# unpack ip from packed client address
my ($port, $iaddr) = sockaddr_in($pa);
my $peer_addr = inet_ntoa($iaddr);
# if the beacon has a length longer than a certain amount, assume it is
# a fraud or crash attempt
if (length $b > 64) {
# log
$self->log("attack","length exceeded in beacon: $peer_addr:$port sent $b");
# truncate and try to continue
$b = substr $b, 0, 64;
}
# if a heartbeat format was detected...
$self->process_udp_beacon($udp, $pa, $b, $peer_addr, $port)
if ($b =~ m/\\heartbeat\\/ && $b =~ m/\\gamename\\/);
# or if this is a secure response, verify the response code and add mark it verified
$self->process_udp_validate($b, $peer_addr, $port, undef)
if ($b =~ m/\\validate\\/);
}
1;
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