More than 100 lines of PHP code to implement socks5 proxy server[2]

<&#63;php
class Client
{
 public $connected = true;
 public $data = '';
 public $remote = null;
 public $status = 0;
}
class Server
{
 public $clients = [];
 public function start()
 {
  $server = new swoole_server('0.0.0.0', 8388, SWOOLE_BASE, SWOOLE_SOCK_TCP);
  $server->set([
   'max_conn' => 1000, 
   'daemonize' => 1,
   'reactor_num' => 1,
   'worker_num' => 1,
   'dispatch_mode' => 2,
   'buffer_output_size' => 128 * 1024 * 1024,
   'open_cpu_affinity' => 1,
   'open_tcp_nodelay' => 1,
   'log_file' => 'socks5_server.log',
  ]);
  $server->on('connect', [$this, 'onConnect']);
  $server->on('receive', [$this, 'onReceive']);
  $server->on('close', [$this, 'onClose']);
  $server->start();
 }
 public function onConnect($server, $fd, $fromID)
 {
  $this->clients[$fd] = new Client();
 }
 public function onReceive($server, $fd, $fromID, $data)
 {
  ($this->clients[$fd])->data .= $data;
  $this->parse($server, $fd); 
 }
 public function onClose($server, $fd, $fromID)
 {
  $client = $this->clients[$fd];
  $client->connected = false;
 }
 private function parse($server, $fd) 
 {
  $client = $this->clients[$fd];

  switch ($client->status) {
   case 0: {
    if (strlen($client->data) >= 2) {
     $request = unpack('c*', substr($client->data, 0, 2));
     if ($request[1] !== 0x05) {
      echo '协议不正确:' . $request[1], PHP_EOL;
      $server->close($fd);
      break;
     }
     $nmethods = $request[2];
     if (strlen($client->data) >= 2 + $nmethods) {
      $client->data = substr($client->data, 2 + $nmethods);
      $server->send($fd, "\x05\x00");
      $client->status = 1;
     }
    }
   }
   case 1: {
    if (strlen($client->data) < 5)
     break;
    $request = unpack('c*', $client->data);
    $aType = $request[4];
    if ($aType === 0x03) { // domain
     $domainLen = $request[5];
     if (strlen($client->data) < 5 + $domainLen + 2) { 
      break; 
     }
     $domain = substr($client->data, 5, $domainLen);
     $port = unpack('n', substr($client->data, 5 + $domainLen, 2))[1]; 
     $client->data = substr($client->data, 5 + $domainLen + 2);
    } else if ($aType === 0x01) { // ipv4
     $domain = long2ip(unpack('N', substr($client->data, 4, 4))[1]);
     $port = unpack('n', substr($client->data, 8, 2))[1]; 
     $client->data = substr($client->data, 10);
    } else {
     echo '不支持的atype:' . $aType, PHP_EOL;
     $server->close($fd);
     break;
    }

    $remote = new swoole_client(SWOOLE_SOCK_TCP, SWOOLE_SOCK_ASYNC);
    $remote->on('connect', function($cli) use($client, $server, $fd, $remote) {
     $server->send($fd, "\x05\x00\x00\x01\x00\x00\x00\x00\x00\x00");
     $client->status = 2;
     $client->remote = $remote;
    });
    $remote->on("error", function(swoole_client $cli) use($server, $fd) {
     //$server->send($fd, ""); // todo 连接不上remote
     echo 'connect to remote error.', PHP_EOL;
     $server->close($fd);
    });
    $remote->on('receive', function($cli, $data) use($server, $fd, $client) {
     if (!$client->connected) {
      echo 'connection has been closed.', PHP_EOL;
      return;
     }
     $server->send($fd, $data);
    });
    $remote->on('close', function($cli) use($server, $fd, $client) {
     $client->remote = null;
    });
    if ($aType === 0x03) {
     swoole_async_dns_lookup($domain, function($host, $ip) use($remote, $port, $server, $fd) {
      //todo 当host为空时的处理。貌似不存在的域名都解析成了本机的外网ip，奇怪
      if (empty($ip) || empty($host)) {
       echo "host:{$host}, ip:{$ip}\n";
       $server->close($fd);
       return;
      }
      $remote->connect($ip, $port);
     });
    } else {
     $remote->connect($domain, $port);
    }
   }
   case 2: {
    if (strlen($client->data) === 0) {
     break;
    }
    if ($client->remote === null) {
     echo 'remote connection has been closed.', PHP_EOL;
     break;
    }

    $sendByteCount = $client->remote->send($client->data);
    if ($sendByteCount === false || $sendByteCount < strlen($client->data)) {
     echo 'data length:' , strlen($client->data), ' send byte count:', $sendByteCount, PHP_EOL; 
     echo $client->data, PHP_EOL;
     $server->close($fd); 
    }
    $client->data = '';
   }
  }
 }
}

(new Server())->start();