t/socks4-proxy.pl

   1 use strict;
   2 use IO::Select;
   3 use IO::Socket::UNIX;
   4 use IO::Socket::INET;
   5
   6 my $path = shift;
   7
   8 unlink($path);
   9 my $server = IO::Socket::UNIX->new(Listen => 1, Local => $path)
  10         or die "unable to listen on $path: $!";
  11
  12 $| = 1;
  13 print "ready\n";
  14
  15 while (my $client = $server->accept()) {
  16         sysread $client, my $buf, 8;
  17         my ($version, $cmd, $port, $ip) = unpack 'CCnN', $buf;
  18         next unless $version == 4; # socks4
  19         next unless $cmd == 1; # TCP stream connection
  20
  21         # skip NUL-terminated id
  22         while (sysread $client, my $char, 1) {
  23                 last unless ord($char);
  24         }
  25
  26         # version(0), reply(5a == granted), port (ignored), ip (ignored)
  27         syswrite $client, "\x00\x5a\x00\x00\x00\x00\x00\x00";
  28
  29         my $remote = IO::Socket::INET->new(PeerHost => $ip, PeerPort => $port)
  30                 or die "unable to connect to $ip/$port: $!";
  31
  32         my $io = IO::Select->new($client, $remote);
  33         while ($io->count) {
  34                 for my $fh ($io->can_read(0)) {
  35                         for my $pair ([$client, $remote], [$remote, $client]) {
  36                                 my ($from, $to) = @$pair;
  37                                 next unless $fh == $from;
  38
  39                                 my $r = sysread $from, my $buf, 1024;
  40                                 if (!defined $r || $r <= 0) {
  41                                         $io->remove($from);
  42                                         next;
  43                                 }
  44                                 syswrite $to, $buf;
  45                         }
  46                 }
  47         }
  48 }