#!/usr/bin/perl
# internal settings
my $daemon = 1; #run as a daemon or not (1/0) 
our $local_host = "0.0.0.0"; 
our $local_port = 60088;
$auth_enabled = 0; #auth enable or not (1/0) 
$auth_login = ""; 
$auth_pass = "";

use IO::Socket::INET; 
$SIG{'CHLD'} = 'IGNORE'; 
$bind = IO::Socket::INET->new(Listen=>10, Reuse=>1, 
LocalAddr=>$local_host, 
LocalPort=>$local_port) or die "Can't bind port $local_port\n"; if ($daemon) {
    # print "Now entering process into the background...\n";
    if (fork()) { close(); exit(); }
}
while($client = $bind->accept()) {
 $client->autoflush();
 if(fork()){ $client->close(); }
 else { $bind->close(); new_client($client); exit(); }
} 
sub new_client {
 local $t, $i, $buff, $ord, $success;
 local $client = $_[0];
 sysread($client, $buff, 1);
 if(ord($buff) == 5) {
   sysread($client, $buff, 1);
   $t = ord($buff);
   unless(sysread($client, $buff, $t) == $t) { return; }
   $success = 0;
   for($i = 0; $i < $t; $i++) {
     $ord = ord(substr($buff, $i, 1));
     if($ord == 0 && !$auth_enabled) {
       syswrite($client, "\x05\x00", 2);
       $success++;
       break;
     } 
     elsif($ord == 2 && $auth_enabled) {
       unless(do_auth($client)){ return; }
       $success++;
       break;
     } 
   } 
   if($success) {
     $t = sysread($client, $buff, 3);
     if(substr($buff, 0, 1) == '\x05') {
       if(ord(substr($buff, 2, 1)) == 0) { # reserved
         ($host, $raw_host) = socks_get_host($client);
         if(!$host) { return; }
         ($local_port, $raw_port) = socks_get_port($client);
         if(!$local_port) { return; }
         $ord = ord(substr($buff, 1, 1));
         $buff = "\x05\x00\x00".$raw_host.$raw_port;
         syswrite($client, $buff, length($buff));
         socks_do($ord, $client, $host, $local_port);
       } 
     } 
   } else { syswrite($client, "\x05\xFF", 2); };
 } 
 $client->close();
} 
sub do_auth {
 local $buff, $login, $pass;
 local $client = $_[0];
 syswrite($client, "\x05\x02", 2);
 sysread($client, $buff, 1);
    $c = ord($buff);
 if(ord($buff) == 1) {
   sysread($client, $buff, 1);
   sysread($client, $login, ord($buff));
   sysread($client, $buff, 1);
   sysread($client, $pass, ord($buff));
   if($login eq $auth_login && $pass eq $auth_pass) {
     syswrite($client, "\x05\x00", 2);
     return 1;
   } else { syswrite($client, "\x05\x01", 2); }
 } 
 $client->close();
 return 0;
} 
sub socks_get_host {
 local $client = $_[0];
 local $t, $ord, $raw_host;
 local $host = "";
 sysread($client, $t, 1);
 $ord = ord($t);
 if($ord == 1) {
   sysread($client, $raw_host, 4);
   @host = $raw_host =~ /(.)/g;
   $host = 
ord($host[0]).".".ord($host[1]).".".ord($host[2]).".".ord($host[3]);
 } elsif($ord == 3) {
   sysread($client, $raw_host, 1);
   sysread($client, $host, ord($raw_host));
   $raw_host .= $host;
 } elsif($ord == 4) {
   #ipv6 - not supported
 } 
 return ($host, $t.$raw_host);
} 
sub socks_get_port {
 local $client = $_[0];
 local $raw_port, $local_port;
 sysread($client, $raw_port, 2);
 $local_port = ord(substr($raw_port, 0, 1)) << 8 | ord(substr($raw_port, 
1, 1));
 return ($local_port, $raw_port);
} 
sub socks_do {
 local($t, $client, $host, $local_port) = @_;
 if($t == 1) { socks_connect($client, $host, $local_port); }
 elsif($t == 2) { socks_bind($client, $host, $local_port); }
 elsif($t == 3) { socks_udp_associate($client, $host, $local_port); }
 else { return 0; }
 return 1;
} 
# this part of code was taken from datapipe.pl utility, written by 
# CuTTer (cutter[at]real.xakep.ru) utility lays on cpan.org
sub socks_connect {
 my($client, $host, $local_port) = @_;
 my $target = IO::Socket::INET->new(LocalHost => $local_host, PeerAddr 
=> $host, PeerPort => $local_port, Proto => 'tcp', Type => SOCK_STREAM);
 unless($target) { return; }
 $target->autoflush();
 while($client || $target) {
   my $rin = "";
   vec($rin, fileno($client), 1) = 1 if $client;
   vec($rin, fileno($target), 1) = 1 if $target;
   my($rout, $eout);
   select($rout = $rin, undef, $eout = $rin, 120);
   if (!$rout && !$eout) { return; }
   my $cbuffer = "";
   my $tbuffer = "";
   if ($client && (vec($eout, fileno($client), 1) || vec($rout, 
fileno($client), 1))) {
     my $result = sysread($client, $tbuffer, 1024);
     if (!defined($result) || !$result) { return; }
   } 
   if ($target && (vec($eout, fileno($target), 1) || vec($rout, 
fileno($target), 1))) {
     my $result = sysread($target, $cbuffer, 1024);
     if (!defined($result) || !$result) { return; }
     } 
   if ($fh && $tbuffer) { print $fh $tbuffer; }
   while (my $len = length($tbuffer)) {
     my $res = syswrite($target, $tbuffer, $len);
     if ($res > 0) { $tbuffer = substr($tbuffer, $res); } else { return; 
}
   } 
   while (my $len = length($cbuffer)) {
     my $res = syswrite($client, $cbuffer, $len);
     if ($res > 0) { $cbuffer = substr($cbuffer, $res); } else { return; 
}
   } 
 } 
} 
sub socks_bind {
 my($client, $host, $local_port) = @_;
 # not supported
} 
sub socks_udp_associate {
 my($client, $host, $local_port) = @_;
 # not supported
}