#!/usr/bin/perl# Written by Alain Knaff# Small test program to send messages to an UDP portuse strict;use IO::Socket::INET;use Getopt::Std;use English;use vars qw($opt_p $opt_i $opt_f $opt_h $opt_I);getopts("p:i:f:hI:");if(defined $opt_h) {  die "Usage: $0 -h [-p port] [-i ip] [-f file] [-I mcast_interface]\n";}if(!defined $opt_p) {    die "Port (-p) missing\n";}if(!defined $opt_i) {    $opt_i = '127.0.0.1';}my $data;if(defined $opt_f) {    open(DATA, "<$opt_f") || die "Could not open $opt_f ($ERRNO)\n";    sysread(DATA, $data, 64000);    close(DATA);} else {    $data=$ARGV[0];}my $sock =     new IO::Socket::INET(Proto => 'udp');if(!defined $sock) {    die "Could not open socket at port $opt_p ($ERRNO)\n";}sub fill_mreq {  my ($mcast, $if) = @_;  my $mreq;  if($if =~ /^([0-9.]*)$/) {    $mreq = pack("a4C4i", $mcast, split(/\./, $if),0);  } else {    my $idx = pack("a16i",$if,0);    # SIOCGIFINDEX 0x8933    if(!defined ioctl($sock, 0x8933, $idx)) {      die "Interface $if not found\n";    }    my ($name, $n) = unpack("a16i", $idx);    $mreq = pack("a4ii", $mcast,0,$n);  }  return $mreq;}my $iaddr = gethostbyname($opt_i);my $toAddr = sockaddr_in($opt_p, $iaddr);if(defined $opt_I) {  my $mreq=fill_mreq($iaddr, $opt_I);  # IPPROTO_IP = 0  # IP_MULTICAST_IF = 32  $sock->setsockopt(0, 32, $mreq) ||    die "ERROR: setsockopt: $!\n";}my $ret = $sock->send($data, 0, $toAddr);1;