//
// smtp_listener.php : explicit
//
//VGR18012006 Création
//VGR20012006 MOD to reply "250 OK" all the time as per RFC http://www.ietf.org/rfc/rfc0821.txt
//            MOD all error handling for socket_* functions, "<0" is wrong, "===FALSE" is right
//
// TODO : Nil
//

//error_reporting(E_ALL);

//set_time_limit(0);
//ob_implicit_flush();

$address = '127.0.0.1';
$port = 25;

$eoln="\r\n";

echo "socket_create...{$eoln}"; ob_flush(); flush(); sleep(1);

if (($sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP))===FALSE) { // boolean
   echo "socket_create() failed : reason : " . socket_strerror($sock).$eoln;
   exit;
}

echo "socket_create OK{$eoln}"; ob_flush(); flush(); sleep(1);

if (!($ret=socket_bind($sock, $address, $port))) { // boolean
   echo "socket_bind() failed : reason : " . socket_strerror($ret).$eoln;
   exit;
}

echo "socket_bind OK{$eoln}"; ob_flush(); flush(); sleep(1);

if (!($ret=socket_listen($sock,5))) { // boolean
   echo "socket_listen() failed : reason : " . socket_strerror($ret).$eoln;
   exit;
}

if (!socket_set_nonblock($sock)) { // boolean
   echo "socket_set_nonblock() failed : reason : " . socket_strerror($ret).$eoln;
   exit;
}

echo "socket_listen OK{$eoln}"; ob_flush(); flush(); sleep(1);

do {
   if (($msgsock=socket_accept($sock))===FALSE) { //VGR REM this is a blocking socket
       echo "socket_accept() failed : reason : " . socket_strerror($msgsock).$eoln; ob_flush(); flush(); sleep(1);
       break;
   } else echo "socket_accept OK{$eoln}"; ob_flush(); flush(); sleep(1);
   /* Send ACK. */
   $msg = "220 VGRTEST Simple Mail Transfer Service Ready\n";
   socket_write($msgsock, $msg, strlen($msg));
   echo "ACKed with '$msg'{$eoln}"; ob_flush(); flush(); sleep(1);
   do {
       if (FALSE === ($buf = @socket_read($msgsock, 2048, PHP_NORMAL_READ))) { //VGR REM , PHP_NORMAL_READ
           echo "socket_read() failed : reason : " . socket_strerror($ret).$eoln; ob_flush(); flush(); sleep(1);
           break 2;
       } else echo "socket_read '$buf' OK{$eoln}"; ob_flush(); flush(); sleep(1);
       if (!$buf = trim($buf)) {
           continue;
       }
       $bufs=explode($buf,' ');
       if ($buf=="\r\n\r\n") { //VGR REM end of transmission of DATA segment
           socket_close($msgsock);
           echo "EOLN{$eoln}"; ob_flush(); flush(); sleep(1);
           break 2;
       } elseif ($bufs[0]=='HELO') {
         $talkback="250 VGRTEST\n";
       } elseif ($bufs[0]=='QUIT') {
         $talkback="221 VGRTEST Service closing transmission channel\n";
       } elseif ($bufs[0]=='DATA') {
         $talkback="354 send the mail data, end with .\n";
       } else $talkback="250 OK\n";
       socket_write($msgsock, $talkback, strlen($talkback));
       echo "$buf{$eoln}"; ob_flush(); flush(); sleep(1);
   } while (true);
   socket_close($msgsock);
} while (true);

socket_close($sock);