io.github.aomsweet.cyber.socks.Socks5ClientRelayHandler Maven / Gradle / Ivy

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/*
  Copyright 2021 The Cyber Project

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
 */
package io.github.aomsweet.cyber.socks;

import io.github.aomsweet.cyber.*;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.socksx.v5.*;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.net.InetSocketAddress;

/**
 * @author aomsweet
 */
public final class Socks5ClientRelayHandler extends ClientRelayHandler {

    private final static InternalLogger logger = InternalLoggerFactory.getInstance(Socks5ClientRelayHandler.class);

    public static final DefaultSocks5InitialResponse NO_AUTH_RESPONSE = new DefaultSocks5InitialResponse(Socks5AuthMethod.NO_AUTH);
    public static final DefaultSocks5InitialResponse PASSWORD_RESPONSE = new DefaultSocks5InitialResponse(Socks5AuthMethod.PASSWORD);

    public static final DefaultSocks5PasswordAuthResponse AUTH_SUCCESS = new DefaultSocks5PasswordAuthResponse(Socks5PasswordAuthStatus.SUCCESS);
    public static final DefaultSocks5PasswordAuthResponse AUTH_FAILURE = new DefaultSocks5PasswordAuthResponse(Socks5PasswordAuthStatus.FAILURE);

    public Socks5ClientRelayHandler(CyberServer cyber) {
        super(cyber, logger);
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        ChannelPipeline pipeline = ctx.pipeline();
        if (msg instanceof Socks5InitialRequest) {
            initialRequestHandler(ctx, (Socks5InitialRequest) msg, pipeline);
        } else if (msg instanceof Socks5PasswordAuthRequest) {
            authRequestHandler(ctx, (Socks5PasswordAuthRequest) msg, pipeline);
        } else if (msg instanceof Socks5CommandRequest) {
            cmdRequestHandler(ctx, (Socks5CommandRequest) msg, pipeline);
        } else {
            ctx.fireChannelRead(msg);
        }
    }

    protected void initialRequestHandler(ChannelHandlerContext ctx, Socks5InitialRequest initialRequest, ChannelPipeline pipeline) {
        Object response;
        if (cyber.getProxyAuthenticator() != null
            || initialRequest.authMethods().contains(Socks5AuthMethod.PASSWORD)) {
            pipeline.replace(HandlerNames.DECODER, HandlerNames.DECODER, new Socks5PasswordAuthRequestDecoder());
            response = PASSWORD_RESPONSE;
        } else {
            pipeline.replace(HandlerNames.DECODER, HandlerNames.DECODER, new Socks5CommandRequestDecoder());
            response = NO_AUTH_RESPONSE;
        }
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
    }

    protected void authRequestHandler(ChannelHandlerContext ctx, Socks5PasswordAuthRequest authRequest, ChannelPipeline pipeline) {
        credentials = new Credentials(authRequest.username(), authRequest.password());
        ProxyAuthenticator proxyAuthenticator = cyber.getProxyAuthenticator();
        if (proxyAuthenticator == null || proxyAuthenticator.authenticate(authRequest.username(), authRequest.password())) {
            pipeline.replace(HandlerNames.DECODER, HandlerNames.DECODER, new Socks5CommandRequestDecoder());
            ctx.writeAndFlush(AUTH_SUCCESS).addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
        } else {
            ctx.writeAndFlush(AUTH_FAILURE).addListener(ChannelFutureListener.CLOSE);
        }
    }

    protected void cmdRequestHandler(ChannelHandlerContext ctx, Socks5CommandRequest request, ChannelPipeline pipeline) throws Exception {
        if (request.type() == Socks5CommandType.CONNECT) {
            serverAddress = InetSocketAddress.createUnresolved(request.dstAddr(), request.dstPort());
            doConnectServer(ctx, ctx.channel(), request);
        } else {
            logger.error("Unsupported Socks5 {} command.", request.type());
            release(ctx);
        }
    }

    @Override
    protected void onConnected(ChannelHandlerContext ctx, Channel clientChannel, Socks5CommandRequest request) {
        Object response = new DefaultSocks5CommandResponse(Socks5CommandStatus.SUCCESS,
            request.dstAddrType(), request.dstAddr(), request.dstPort());
        ctx.writeAndFlush(response);
        ChannelPipeline pipeline = clientChannel.pipeline();
        pipeline.remove(HandlerNames.DECODER);
        pipeline.remove(Socks5ServerEncoder.DEFAULT);
        doServerRelay(ctx);
    }

    @Override
    protected void onConnectFailed(ChannelHandlerContext ctx, Channel clientChannel, Socks5CommandRequest request) {
        Object response = new DefaultSocks5CommandResponse(Socks5CommandStatus.FAILURE, request.dstAddrType());
        ctx.writeAndFlush(response).addListener(future -> release(ctx));
    }
}