UDP socket_read接收数据导致错误Resource temporarily unavailable

项目中经常用到PHP用UDP调用C++服务，我们这边的PHP 请求方法封装如下，一直没有问题出现，今天接入新的服务出现了问题

   public static  function request($reqBuffer,$host,$port)
    {

        $socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
        //设置发送数据超时时间
        socket_set_option($socket, SOL_SOCKET, SO_SNDTIMEO, array("sec" => 0, "usec" => 500000));
        //设置接收数据超时时间
        socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, array("sec" => 0, "usec" => 500000));
        if (socket_connect($socket, $host, $port) === false) {
            socket_close($socket);
            throw new Exception('connect server error'.socket_strerror(socket_last_error()), 100);
        }
        if (socket_write($socket, $reqBuffer, strlen($reqBuffer)) === false) {
            socket_close($socket);
            throw new Exception('send request error'.socket_strerror(socket_last_error()), 100);
        }
        if (($rspBuffer = socket_read($socket, 65536)) === false) {
            socket_close($socket);
            throw new Exception('receive response error'.socket_strerror(socket_last_error()), 100);
        }
        socket_close($socket);
        return $rspBuffer;
    }

问题如下：
socket_read 一直返回false 错误信息:Resource temporarily unavailable，而用tcpdump抓包显示C++服务已经回报，抓包数据如下：

[img]http://dl2.iteye.com/upload/attachment/0104/2638/834b4d13-7d6b-3b69-ae93-3caaffc87370.png[/img]

ICMP回报表示C++服务 230 发送的UDP包没有程序socket_read没有接收

这就是问题tcpdump显示数据已经发送 但是socket_read显示Resource temporarily unavailable


后来测试正常的请求才发现 ，服务器发送数据的端口从11188 变成成了11177 ，下面是可以收到的抓包

[img]http://dl2.iteye.com/upload/attachment/0104/2640/a3a866b9-dc8e-3048-9b97-0f94af92c357.png[/img]


后来发现socket_read不能接收端口变化的数据，适合与TCP这种保持连接，整个过程端口不变化的socket，而socket_recvfrom可以处理这种情况

然后函数封装换成了下面的方式：

    public static functionrequest($reqBuffer, $host, $port)
    {

        $socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
        //设置发送数据超时时间
        socket_set_option($socket, SOL_SOCKET, SO_SNDTIMEO, array("sec" => 0, "usec" => 500000));
        //设置接收数据超时时间
        socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, array("sec" => 0, "usec" => 500000));

        if (socket_sendto($socket,$reqBuffer, strlen($reqBuffer),0,$host,$port) === false) {
            socket_close($socket);
            throw new Exception('send request errorr' . socket_strerror(socket_last_error()), 100);
        }
        $from = "";
        $port = 0;
        if (socket_recvfrom($socket, $rspBuffer, 65536, 0, $from, $port) === false) {
            socket_close($socket);
            throw new Exception('receive response error' . socket_strerror(socket_last_error()), 100);
        }
        socket_close($socket);
        return $rspBuffer;
    }

现在OK了 不在会用ICMP回报未接收到数据

[img]http://dl2.iteye.com/upload/attachment/0104/2642/d67022b8-4505-3f87-81f5-da348518204a.png[/img]