[PHP知识库]关于打洞技术的小实验

打洞其实很简单，写一个打洞服务器，然后客户端把自己路由器的ip和端口注册到打洞服务器上，然后打洞服务器去告诉另一个客户端，希望交流的客户端路由器的ip和端口，因为路由器有NAT和NATP，对外暴露的ip和端口不一定是本机的，在这里主要做本地的模拟，线上的其实也很简单，tcp与udp都可以打洞

通讯框架用的swoole,通讯技术和语言没有任何关系，不要纠结语言

一个打洞服务器:

<?php

$arr = [];


$server = new Swoole\Server('127.0.0.1', 9503, SWOOLE_PROCESS, SWOOLE_SOCK_UDP);
$server->set([
    "worker_num" => 1
]);
$server->on('packet', function ($server, $data, $clientInfo) use (&$arr){
    $list = explode("\n", $data);
    foreach ($list as $value) {
        $data = json_decode($value, 1);
        if ($data) {
            if ($data["do"] == "reg") {
                $arr[$data["user"]] = $clientInfo;
                var_dump($arr);
                $server->sendTo($clientInfo['address'], $clientInfo['port'], "Server：");
//                $server->send($fd, "ok\n");
            } else if ($data["do"] == "get") {
                $server->sendTo($clientInfo['address'], $clientInfo['port'],
                    json_encode($arr[$data["user"]]));
//                $server->send($fd, json_encode($arr[$data["user"]]));
                //
//                $server->send($arr[$data["user"]]["fd"], json_encode($arr[$data["user"]]));
            } else {

            }
        }
    }
//$server->sendTo($clientInfo['address'], $clientInfo['port'], "Server：{$data}");
});

$server->start();

client2:

<?php
$client = new Swoole\Client(SWOOLE_SOCK_UDP, SWOOLE_SOCK_SYNC);

$r = $client->sendto('127.0.0.1', 9503, json_encode(["do"=>"reg", "user"=>"client2", "passwd" => "passwd"]) . "\n");
$ret = $client->recv();
while (1) {
    $ret = $client->recv();
    if ($ret) {
        var_dump($ret);

    }
    sleep(1);
}
$client->close();

client1:

<?php

$client = new Swoole\Client(SWOOLE_SOCK_UDP, SWOOLE_SOCK_SYNC);

$r = $client->sendto('127.0.0.1', 9503, json_encode(["do"=>"reg", "user"=>"client1", "passwd" => "passwd"]) . "\n");
echo $client->recv();
$r = $client->sendto('127.0.0.1', 9503, json_encode(["do"=>"get", "user"=>"client2"]) . "\n");
$ret = $client->recv();
$data = json_decode($ret, 1);
while (1) {
    $r = $client->sendto($data["address"], $data["port"], "test" . "\n");
    var_dump($r);
    sleep(3);
}

运行这些程序我们发现，swoole的client2 收到了test的数据

当然线上的程序有路由表缓存策略，还要再做处理，tcp配置一下SO_REUSEADDR其实也可以了，就是这么简单