#!/bin/perl -w
# $Id: httpclient 81 2003-03-22 16:39:56Z tach $
# copyright (c)1998-1999 Yoshinori Hasegawa <hasegawa@madoka.org>

if ($] < 5) {
  foreach $inc (@INC) {
    if (-r "$inc/sys/socket.ph") {
      eval 'require "sys/socket.ph"';
      $SOCKET = "$inc/sys/socket.ph" unless $@;
      last;
    }
    if (-r "$inc/socket.ph") {
      eval 'require "socket.ph"';
      $SOCKET = "$inc/socket.ph" unless $@;
      last;
    }
  }
} else {
  eval 'use Socket';
  $SOCKET = 'Socket.pm' unless $@;
}

$NIL = $;;

$READSIZE = 1024;
$SOCKADDR = 'S n N x8';

$PROTO = (getprotobyname('tcp'))[2];

$AF_INET = eval '&AF_INET' || 2;
$PF_INET = eval '&PF_INET' || 2;
$SOCK_STREAM = eval '&SOCK_STREAM' || 1;
$SOMAXCONN = eval '&SOMAXCONN' || 16;
$INADDR_ANY = eval '&INADDR_ANY' || "\0\0\0\0";
$SOL_SOCKET = eval '&SOL_SOCKET';
$SO_REUSEADDR = eval '&SO_REUSEADDR';

$'rin = '';

$handle = 0;

$SIG{'PIPE'} = 'IGNORE' if &'exist(&'list(keys(%SIG)), 'PIPE');

&main(@ARGV);

sub main {
  local(@args) = @_;
  local($rout, $listenno, $nf, $slist, $clist);
  if (@args < 7) {
    &usage();
    exit(1);
  }
  $listenno = &'listen($args[6], 0) || die "cannot listen port\n";
  for (;;) {
    $nf = select($rout = $'rin, undef, undef, undef);
    die "error in select\n" if $nf < 0;
    foreach $cno (&'array($clist)) {
      next unless vec($rout, $cno, 1);
      &client_read($cno);
    }
    foreach $sno (&'array($slist)) {
      next unless vec($rout, $sno, 1);
      &server_read($sno);
    }
    if (vec($rout, $listenno, 1)) {
      &listen_accept($listenno, $args[0], $args[1], $args[2], $args[3], $args[4], $args[5]);
    }
  }
}

sub client_read {
  local($cno) = @_;
  local($tmp, $socket);
  $tmp = '';
  if (sysread($'socket[$cno], $tmp, $READSIZE)) {
    $socket = $'socket[$peer[$cno]];
    print $socket $tmp if fileno($socket);
  } else {
    &'close($cno);
    $clist = &'remove($clist, $cno);
    &'close($peer[$cno]);
    $slist = &'remove($slist, $peer[$cno]);
  }
}

sub server_read {
  local($sno) = @_;
  local($tmp, $socket, $next, $rest, $stat);
  $tmp = '';
  if (sysread($'socket[$sno], $tmp, $READSIZE)) {
    if ($http[$sno]) {
      $socket = $'socket[$sno];
      $rbuf[$sno] .= $tmp;
      while ((($next, $rest) = split(/\r\n/, $rbuf[$sno], 2)) == 2) {
        $rbuf[$sno] = $rest || '';
        if ($next) {
          $reply[$sno] = &'add($reply[$sno], $next);
        } else {
          $stat = (split(/\s+/, (&'array($reply[$sno]))[0]))[1];
          if ($stat eq '204') {
            $clist = &'add($clist, $peer[$sno]);
            $http[$sno] = 0;
            $socket = $'socket[$peer[$sno]];
            print $socket $rbuf[$sno];  
          } else {
            &'close($sno);
            $slist = &'remove($slist, $sno);
            &'close($peer[$sno]);
          }
          last;
        }
      }
      $rbuf[$sno] = $next || '';
    } else {
      $socket = $'socket[$peer[$sno]];
      print $socket $tmp;
    }
  } else {
    &'close($sno);
    $slist = &'remove($slist, $sno);
    &'close($peer[$sno]);
    $clist = &'remove($clist, $peer[$sno]);
  }
}

sub listen_accept {
  local($listenno, $phost, $pport, $ghost, $gport, $host, $port) = @_;
  local($cno, $sno, $socket);
  if ($cno = &'accept($listenno)) {
    if ($sno = &'connect($phost, $pport)) {
      $socket = $'socket[$sno];
      print $socket "POST http://$ghost:$gport/$host/$port/ HTTP/1.0\r\n";
      print $socket "\r\n";
      $http[$sno] = 1;
      $rbuf[$sno] = '';
      $reply[$sno] = '';
      $peer[$sno] = $cno;
      $peer[$cno] = $sno;
      $slist = &'add($slist, $sno);
    } else {
      &'close($cno);
    }
  }
}

sub usage {
  print 'usage: perl httpclient <proxy-host> <proxy-port> <gateway-host> <gateway-port> <host> <port> <listen-port>', "\n";
}

sub 'connect {
  local($host, $port) = @_;
  local($serverno, $socket, $ip, @addr, $name);
  if ($host =~ /^\d+$/) {
    $ip = $host;
  } elsif ($host =~ /^[\d\.]+$/) {
    @addr = split(/\./, $host);
    $ip = unpack('N', pack('C4', @addr, 0, 0, 0));
  } else {
    $ip = unpack('N', (gethostbyname($host))[4] || "\0\0\0\0");
  }
  return 0 unless $ip;
  $socket = '\'S' . ++$handle;
  socket($socket, $PF_INET, $SOCK_STREAM, $PROTO) || return 0;
  $name = pack($SOCKADDR, $AF_INET, $port, $ip);
  connect($socket, $name) || return 0;
  binmode($socket);
  $serverno = fileno($socket);
  vec($'rin, $serverno, 1) = 1;
  $'socket[$serverno] = $socket;
  select((select($socket), $| = 1)[0]);
  $'access[$serverno] = time();
  return $serverno;
}

sub 'listen {
  local($port, $count) = @_;
  local($listenno, $socket, $name);
  $socket = '\'L' . ++$handle;
  socket($socket, $PF_INET, $SOCK_STREAM, $PROTO) || return 0;
  if (defined($SOL_SOCKET) && defined($SO_REUSEADDR)) {
    setsockopt($socket, $SOL_SOCKET, $SO_REUSEADDR, pack('l', 1));
  }
  $name = pack($SOCKADDR, $AF_INET, $port, unpack('N', $INADDR_ANY));
  bind($socket, $name) || return 0;
  listen($socket, $count || $SOMAXCONN) || return 0;
  $listenno = fileno($socket);
  vec($'rin, $listenno, 1) = 1;
  $'socket[$listenno] = $socket;
  select((select($socket), $| = 1)[0]);
  $'access[$listenno] = time();
  return $listenno;
}

sub 'accept {
  local($listenno) = @_;
  local($clientno, $socket);
  $socket = '\'C' . ++$handle;
  accept($socket, $'socket[$listenno]) || return 0;
  binmode($socket);
  $clientno = fileno($socket);
  vec($'rin, $clientno, 1) = 1;
  $'socket[$clientno] = $socket;
  select((select($socket), $| = 1)[0]);
  $'access[$clientno] = time();
  return $clientno;
}

sub 'close {
  local($no) = @_;
  close($'socket[$no]);
  vec($'rin, $no, 1) = 0;
}

sub 'add {
  local($list, @items) = @_;
  $list = '' unless $list;
  foreach $item (@items) {
    next if &'exist($list, $item);
    $list .= $NIL . $item;
  }
  return $list;
}

sub 'remove {
  local($list, @items) = @_;
  local($idx);
  $list = '' unless $list;
  $list .= $NIL;
  foreach $item (@items) {
    $idx = index("\L$list\E", $NIL . "\L$item\E" . $NIL);
    next if $idx == -1;
    substr($list, $idx, length($NIL . $item . $NIL)) = $NIL;
  }
  return substr($list, 0, length($list) - 1);
}

sub 'exist {
  local($list, @items) = @_;
  return 0 unless $list;
  $list .= $NIL;
  foreach $item (@items) {
    return 1 if index("\L$list\E", $NIL . "\L$item\E" . $NIL) != -1;
  }
  return 0;
}

sub 'list {
  local(@array) = @_;
  return join($NIL, '', @array);
}

sub 'array {
  local($list) = @_;
  return () unless $list;
  $list = substr($list, 1);
  return () unless $list;
  return split(/$NIL/, $list);
}
