1#!/usr/bin/perl 2 3# Copyright (C) Internet Systems Consortium, Inc. ("ISC") 4# 5# SPDX-License-Identifier: MPL-2.0 6# 7# This Source Code Form is subject to the terms of the Mozilla Public 8# License, v. 2.0. If a copy of the MPL was not distributed with this 9# file, you can obtain one at https://mozilla.org/MPL/2.0/. 10# 11# See the COPYRIGHT file distributed with this work for additional 12# information regarding copyright ownership. 13 14use IO::Socket; 15use IO::File; 16use strict; 17 18# Ignore SIGPIPE so we won't fail if peer closes a TCP socket early 19local $SIG{PIPE} = 'IGNORE'; 20 21# Flush logged output after every line 22local $| = 1; 23 24my $server_addr = "10.53.0.4"; 25if (@ARGV > 0) { 26 $server_addr = @ARGV[0]; 27} 28 29my $localport = int($ENV{'PORT'}); 30if (!$localport) { $localport = 5300; } 31 32my $udpsock = IO::Socket::INET->new(LocalAddr => "$server_addr", 33 LocalPort => $localport, Proto => "udp", Reuse => 1) or die "$!"; 34 35print "listening on $server_addr:$localport.\n"; 36 37my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!"; 38print $pidf "$$\n" or die "cannot write pid file: $!"; 39$pidf->close or die "cannot close pid file: $!";; 40sub rmpid { unlink "ans.pid"; exit 1; }; 41 42$SIG{INT} = \&rmpid; 43$SIG{TERM} = \&rmpid; 44 45# Main 46for (;;) { 47 my $rin; 48 my $rout; 49 50 $rin = ''; 51 vec($rin, fileno($udpsock), 1) = 1; 52 53 select($rout = $rin, undef, undef, undef); 54 55 if (vec($rout, fileno($udpsock), 1)) { 56 printf "UDP request\n"; 57 my $buf; 58 $udpsock->recv($buf, 512); 59 } 60} 61