Add Socks5SocketConnector from amphp/http-tunnel

Imported from https://github.com/amphp/http-tunnel/blob/4b3e7cd4f883a9d118a480596096b2119bbf4b63/src/Socks5TunnelConnector.php

src/Socks5SocketConnector.php

@@ -0,0 +1,179 @@
+<?php declare(strict_types=1);
+
+namespace Amp\Socket;
+
+use Amp\ByteStream\StreamException;
+use Amp\Cancellation;
+use Amp\ForbidCloning;
+use Amp\ForbidSerialization;
+use League\Uri\Uri;
+
+/** @api */
+final class Socks5SocketConnector implements SocketConnector
+{
+    private const REPLIES = [
+        0 => 'succeeded',
+        1 => 'general SOCKS server failure',
+        2 => 'connection not allowed by ruleset',
+        3 => 'Network unreachable',
+        4 => 'Host unreachable',
+        5 => 'Connection refused',
+        6 => 'TTL expired',
+        7 => 'Command not supported',
+        8 => 'Address type not supported'
+    ];
+
+    /**
+     * @throws StreamException
+     * @see https://datatracker.ietf.org/doc/html/rfc1928#section-3
+     */
+    private static function writeHello(?string $username, ?string $password, Socket $socket): void
+    {
+        $methods = \chr(0);
+        if (isset($username) && isset($password)) {
+            $methods .= \chr(2);
+        }
+
+        $socket->write(\chr(5) . \chr(\strlen($methods)) . $methods);
+    }
+
+    /**
+     * @throws SocketException
+     * @throws StreamException
+     * @see https://datatracker.ietf.org/doc/html/rfc1928#section-4
+     */
+    private static function writeConnectRequest(Uri $uri, Socket $socket): void
+    {
+        $host = $uri->getHost();
+        if ($host === null) {
+            throw new SocketException("Host is null!");
+        }
+
+        $payload = \pack('C3', 0x5, 0x1, 0x0);
+
+        $ip = \inet_pton($host);
+        if ($ip !== false) {
+            $payload .= \chr(\strlen($ip) === 4 ? 0x1 : 0x4) . $ip;
+        } else {
+            $payload .= \chr(0x3) . \chr(\strlen($host)) . $host;
+        }
+
+        $payload .= \pack('n', $uri->getPort());
+
+        $socket->write($payload);
+    }
+
+    use ForbidCloning;
+    use ForbidSerialization;
+
+    public static function tunnel(
+        Socket $socket,
+        string $target,
+        ?string $username,
+        ?string $password,
+        ?Cancellation $cancellation
+    ): Socket {
+        if (($username === null) !== ($password === null)) {
+            throw new \Error("Both or neither username and password must be provided!");
+        }
+
+        $uri = Uri::createFromString($target);
+
+        $read = function (int $length) use ($socket, $cancellation): string {
+            \assert($length > 0);
+
+            $buffer = '';
+
+            do {
+                $chunk = $socket->read($cancellation, $length - \strlen($buffer));
+                if ($chunk === null) {
+                    throw new SocketException("The socket was closed before the tunnel could be established");
+                }
+
+                $buffer .= $chunk;
+            } while (\strlen($buffer) !== $length);
+
+            return $buffer;
+        };
+
+        self::writeHello($username, $password, $socket);
+
+        $version = \ord($read(1));
+        if ($version !== 5) {
+            throw new SocketException("Wrong SOCKS5 version: $version");
+        }
+
+        $method = \ord($read(1));
+        if ($method === 2) {
+            if ($username === null || $password === null) {
+                throw new SocketException("Unexpected method: $method");
+            }
+
+            $socket->write(
+                \chr(1) .
+                \chr(\strlen($username)) .
+                $username .
+                \chr(\strlen($password)) .
+                $password
+            );
+
+            $version = \ord($read(1));
+            if ($version !== 1) {
+                throw new SocketException("Wrong authorized SOCKS version: $version");
+            }
+
+            $result = \ord($read(1));
+            if ($result !== 0) {
+                throw new SocketException("Wrong authorization status: $result");
+            }
+        } elseif ($method !== 0) {
+            throw new SocketException("Unexpected method: $method");
+        }
+
+        self::writeConnectRequest($uri, $socket);
+
+        $version = \ord($read(1));
+        if ($version !== 5) {
+            throw new SocketException("Wrong SOCKS5 version: $version");
+        }
+
+        $reply = \ord($read(1));
+        if ($reply !== 0) {
+            $reply = self::REPLIES[$reply] ?? $reply;
+            throw new SocketException("Wrong SOCKS5 reply: $reply");
+        }
+
+        $rsv = \ord($read(1));
+        if ($rsv !== 0) {
+            throw new SocketException("Wrong SOCKS5 RSV: $rsv");
+        }
+
+        $read(match (\ord($read(1))) {
+            0x1 => 6,
+            0x4 => 18,
+            0x3 => \ord($read(1)) + 2
+        });
+
+        return $socket;
+    }
+
+    public function __construct(
+        private readonly SocketAddress|string $proxyAddress,
+        private readonly ?string $username = null,
+        private readonly ?string $password = null,
+        private readonly ?SocketConnector $socketConnector = null
+    ) {
+        if (($username === null) !== ($password === null)) {
+            throw new \Error("Both or neither username and password must be provided!");
+        }
+    }
+
+    public function connect(SocketAddress|string $uri, ?ConnectContext $context = null, ?Cancellation $cancellation = null): Socket
+    {
+        $connector = $this->socketConnector ?? socketConnector();
+
+        $socket = $connector->connect($this->proxyAddress, $context, $cancellation);
+
+        return self::tunnel($socket, (string) $uri, $this->username, $this->password, $cancellation);
+    }
+}