PHP listening Socket

<?php
set_time_limit(10);

$commonProtocol = getprotobyname("tcp");
$socket = socket_create(AF_INET, SOCK_STREAM, $commonProtocol);
if ($socket) {
$result = socket_bind($socket, 'localhost', 1337);
if ($result) {
   $result = socket_listen($socket, 5);
   if ($result) {
    echo "监听成功";
   }
}
}else{
echo "监听失败";
}

do {
if (($msgsock = socket_accept($socket))) { /* 发送提示信息给连接上来的用户 */
   $msg = "==========================================rn" .
   "Welcome to the PHP Test Server. rnrn" .
   "To quit, type 'quit'. rn" .
   "To shut down the server type 'shutdown'.rn" .
   "To get help message type 'help'.rn" .
   "==========================================rn" .
   "php>";
}

socket_write($msgsock, $msg, strlen($msg));

do {
   $buf = socket_read($msgsock, 2048, PHP_BINARY_READ);

   if (false === $buf) {
    echo "socket_read() failed: reason: " . socket_strerror($result) . "n";
    break 2;
   }
   if (!$buf = trim($buf)) {
    continue;
   } /* 客户端输入quit命令时候关闭客户端连接 */
   if ($buf == 'q') {
    break;
   } /* 客户端输入shutdown命令时候服务端和客户端都关闭 */
   if ($buf == 'shutdown') {
    socket_close($msgsock);
    break 2;
   } /* 客户端输入help命令时候输出帮助信息 */
   if ($buf == 'h') {
    $msg = " PHP Server Help Message rnrn" .
    " To quit, type 'quit'. rn" .
    " To shut down the server type 'shutdown'.rn" .
    " To get help message type 'help'.rn" .
    "php> ";
    socket_write($msgsock, $msg, strlen($msg));
    continue;
   } /* 客户端输入命令不存在时提示信息 */
   $talkback = "PHP: unknow command '$buf'.rnphp> ";
   socket_write($msgsock, $talkback, strlen($talkback));
   echo "$bufn";
} while (true);
socket_close($msgsock);
}while (true);
/* 关闭Socket连接 */
socket_close($socket);
?>