#!/usr/bin/perl
# Vincent 'rastakid' van Scherpenseel (rastakid [at] syn-ack [dot] org) - 17 May 2005
#
# World Hopper 0.3 (whopper.pl)
# Simple but powerfull tool to connect to remote services through a chain of HTTP (CONNECT) proxy
# servers, to gain high anonymity. Opens a listening socket at port 1337 (default) and then waits
# for a client to connect. When a client connects World Hopper builds a chain of proxy servers.
# Tested OK with: telnet, pop3 and irc.
#
# Usage: whopper.pl <proxyfile> [options] [dest_host:dest_port]
# Proxyfile should contain HTTP CONNECT proxies, each on a new line (host:port).
# If you omit the destination, your connecting client needs to send the CONNECT method request.
#
# Whopper lives at: https://proximus.syn-ack.org/whopper/
# See https://proximus.syn-ack.org/whopper/changelog.txt for changes.

# Load modules
use strict;
use IO::Socket;
use Net::hostent;
use Fcntl qw(:flock :seek);
use POSIX qw(strftime);

my (@proxies, $proxy_host, $proxy_port, $server, $client, $hostinfo, $server_port, $childpid, $proxy_connection, $line, $iterate, $last_proxy, $non_http_output, $logtraffic, $traffic_log, $clienthost, $destination);

$SIG{CHLD} = 'IGNORE';    # Prevent childs from becoming zombies.

# GLOBAL VARIABLES
$server_port = 1337;    # set server listening port globally (default is: 1337).
$logtraffic = 0;    # enable/disable logtraffic globally (disabled by default).
$traffic_log = "traffic.log";  # set traffic logfile globally (default is: traffic.log).

# Command line reading
if (@ARGV[0] eq "" or @ARGV[0] eq "-H" or @ARGV[0] eq "-h" or @ARGV[0] eq "--help") {
   die "Usage: whopper.pl <proxyfile> [options] [dest_host:dest_port]
   
Options:
   -H, -h, --help\t\t\t\tThis help menu
   -P (--port) <server port>\t\t\tPort to listen for incoming connections
   -L (--logtraffic) <traffic logfile>\t\tLog traffic to <traffic logfile>\n";
}

for ($iterate=1;$iterate<scalar(@ARGV);$iterate++) {
  chomp(@ARGV[$iterate]);
  
  # server listening port
  if(@ARGV[$iterate] eq "-P" or @ARGV[$iterate] eq "--port") {
    chomp(@ARGV[($iterate+1)]);
    $server_port = @ARGV[($iterate+1)];
    $iterate++;    # extra plus 1, argument for -P
  }
  
  # traffic logging
  elsif(@ARGV[$iterate] eq "-L" or @ARGV[$iterate] eq "--logtraffic") {
    $logtraffic = 1;
    chomp(@ARGV[($iterate+1)]);
    $traffic_log = @ARGV[($iterate+1)];
    $iterate++;    # extra plus 1, argument for -L
  }
  
  # user supplied a destination
  else {
    $destination = @ARGV[$iterate];
  }
}

print "\nWorld Hopper 0.3 - Vincent 'rastakid' van Scherpenseel\n";
print "=" x 54 . "\n\n";

# Read proxy servers from file
open(INF,"$ARGV[0]") or die "Fatal: opening proxyfile (@ARGV[0]) failed with error: $!\n";;
@proxies = <INF>;
close(INF);
@proxies = grep(!/^#/, @proxies);     # filter out comments
@proxies = grep(!/^$/, @proxies);    # filter out empty lines
print "[ " . (strftime "%c", localtime) . "\tPID: $$ ] Found " . scalar(@proxies) . " proxy servers in @ARGV[0].\n";

if ($logtraffic) {
  # Open traffic log for appending
  open(TRAFFIC_LOG,">>$traffic_log");
}

# Open listening sockets for clients
$server = IO::Socket::INET->new(LocalPort => $server_port,
                                Type      => SOCK_STREAM,
                                Reuse     => 1,
                                Listen    => SOMAXCONN )
or die "Fatal: listening on port $server_port failed with error: $@\n";
print "[ " . (strftime "%c", localtime) . "\tPID: $$ ] Listening for client connections on port $server_port.\n";

while ($client = $server->accept()) {    # Incoming client connection
  $non_http_output = 0;      # Set to default (no non-HTTP output yet)
  $client->autoflush(1);
  $hostinfo = gethostbyaddr($client->peeraddr);
  $clienthost = $hostinfo ? $hostinfo->name : $client->peerhost;
  printf "\n[ " . (strftime "%c", localtime) . "\tPID: $$ ] Client connection from $clienthost.\n";
   
  # Connect to first proxy server
  chomp($proxies[0]);
  $last_proxy = $proxies[0];
  ($proxy_host,$proxy_port) = split(/:/,$proxies[0]);
  $proxy_connection = IO::Socket::INET->new(Proto     => "tcp",
              PeerAddr  => $proxy_host,
              PeerPort  => $proxy_port)
  or die "Fatal: connecting to proxy server $proxy_host:$proxy_port failed with error: $!";

  $proxy_connection->autoflush(1);
  print "[ " . (strftime "%c", localtime) . "\tPID: $$ ] Connected to $proxy_host:$proxy_port.\n";
  
  if ($logtraffic) {
    # Write line to traffic log
    flock(TRAFFIC_LOG, LOCK_EX);
    seek(TRAFFIC_LOG,0,2);
    print TRAFFIC_LOG "\n\n[ Connection to: $proxy_host:$proxy_port ]\n";
    flock(TRAFFIC_LOG, LOCK_UN);
  }

  # Chain proxy servers
  for ($iterate=1;$iterate<scalar(@proxies);$iterate++) {
    chomp($proxies[$iterate]);
    print $proxy_connection "CONNECT $proxies[$iterate] HTTP/1.0\r\n\r\n";
    $last_proxy = $proxies[$iterate];
    
    if ($logtraffic) {
      # Write line to traffic log
      flock(TRAFFIC_LOG, LOCK_EX);
      seek(TRAFFIC_LOG,0,2);
      print TRAFFIC_LOG ">CONNECT $proxies[$iterate] HTTP/1.0\r\n\r\n";
      flock(TRAFFIC_LOG, LOCK_UN);
    }
  }
   
  # Check if we only need to proxy or if we have a destination too
  if ($destination ne "") {
    print $proxy_connection "CONNECT $destination HTTP/1.0\r\n\r\n";
        
    if ($logtraffic) {
      # Write line to traffic log
      flock(TRAFFIC_LOG, LOCK_EX);
      seek(TRAFFIC_LOG,0,2);
      print TRAFFIC_LOG ">CONNECT $destination HTTP/1.0\r\n\r\n";
      flock(TRAFFIC_LOG, LOCK_UN);
    }
    
  }

  die "Fatal: forking failed with error: $!" unless defined($childpid = fork());

  # Data Input/Output
  if ($childpid) {
    $iterate = 1;
    while (defined ($line = <$proxy_connection>)) {
      
      if ($logtraffic) {
        # Write line to traffic log
        flock(TRAFFIC_LOG, LOCK_EX);
        seek(TRAFFIC_LOG,0,2);
        print TRAFFIC_LOG "<$line";
        flock(TRAFFIC_LOG, LOCK_UN);
      }
    
      # Filter out HTTP code 200s and empty lines on CONNECT (for POP3 and such compatibility)
      if (($line =~ /200 Connection established/ or $line =~ /Proxy-agent:/ or $line =~ /Proxy-Agent:/ or $line eq "\r" or $line eq "\n" or $line eq "\r\n") and $non_http_output == 0) {
                
        if ($line =~ /200 Connection established/) {
          if ($iterate == scalar(@proxies)) {
            print "[ " . (strftime "%c", localtime) . "\tPID: $childpid ] Connected to destination.\n";
          } else {
            print "[ " . (strftime "%c", localtime) . "\tPID: $childpid ] Connected to $proxies[$iterate].\n";
            $iterate++;
          }
        }
        
        $line = "";
      } else {
        $non_http_output = 1;
      }
          
      print $client $line;
      
    }
    kill("TERM", $childpid);
    print "[ " . (strftime "%c", localtime) . "\tPID: $childpid ] Disconnect from client: $clienthost.\n";
  } else {
    while (defined ($line = <$client>)) {
      print $proxy_connection $line;
      
      if ($logtraffic) {
        # Write line to traffic log
        flock(TRAFFIC_LOG, LOCK_EX);
        seek(TRAFFIC_LOG,0,2);
        print TRAFFIC_LOG ">$line";
        flock(TRAFFIC_LOG, LOCK_UN);
      }
      
    }
  }  
}