// // Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2019 // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include "td/net/Socks5.h" #include "td/utils/common.h" #include "td/utils/logging.h" #include "td/utils/misc.h" #include "td/utils/Slice.h" namespace td { void Socks5::send_greeting() { VLOG(proxy) << "Send greeting to proxy"; CHECK(state_ == State::SendGreeting); state_ = State::WaitGreetingResponse; string greeting; greeting += '\x05'; bool use_username = !username_.empty(); char authentication_count = use_username ? '\x02' : '\x01'; greeting += authentication_count; greeting += '\0'; if (use_username) { greeting += '\x02'; } fd_.output_buffer().append(greeting); } Status Socks5::wait_greeting_response() { auto &buf = fd_.input_buffer(); VLOG(proxy) << "Receive greeting response of size " << buf.size(); if (buf.size() < 2) { return Status::OK(); } auto buffer_slice = buf.read_as_buffer_slice(2); auto slice = buffer_slice.as_slice(); if (slice[0] != '\x05') { return Status::Error(PSLICE() << "Unsupported socks protocol version " << int(slice[0])); } auto authentication_method = slice[1]; if (authentication_method == '\0') { send_ip_address(); return Status::OK(); } if (authentication_method == '\x02') { return send_username_password(); } return Status::Error("Unsupported authentication mode"); } Status Socks5::send_username_password() { VLOG(proxy) << "Send username and password"; if (username_.size() >= 128) { return Status::Error("Username is too long"); } if (password_.size() >= 128) { return Status::Error("Password is too long"); } string request; request += '\x01'; request += narrow_cast<char>(username_.size()); request += username_; request += narrow_cast<char>(password_.size()); request += password_; fd_.output_buffer().append(request); state_ = State::WaitPasswordResponse; return Status::OK(); } Status Socks5::wait_password_response() { auto &buf = fd_.input_buffer(); VLOG(proxy) << "Receive password response of size " << buf.size(); if (buf.size() < 2) { return Status::OK(); } auto buffer_slice = buf.read_as_buffer_slice(2); auto slice = buffer_slice.as_slice(); if (slice[0] != '\x01') { return Status::Error(PSLICE() << "Unsupported socks subnegotiation protocol version " << int(slice[0])); } if (slice[1] != '\x00') { return Status::Error("Wrong username or password"); } send_ip_address(); return Status::OK(); } void Socks5::send_ip_address() { VLOG(proxy) << "Send IP address"; callback_->on_connected(); string request; request += '\x05'; request += '\x01'; request += '\x00'; if (ip_address_.is_ipv4()) { request += '\x01'; auto ipv4 = ntohl(ip_address_.get_ipv4()); request += static_cast<char>(ipv4 & 255); request += static_cast<char>((ipv4 >> 8) & 255); request += static_cast<char>((ipv4 >> 16) & 255); request += static_cast<char>((ipv4 >> 24) & 255); } else { request += '\x04'; request += ip_address_.get_ipv6().str(); } auto port = ip_address_.get_port(); request += static_cast<char>((port >> 8) & 255); request += static_cast<char>(port & 255); fd_.output_buffer().append(request); state_ = State::WaitIpAddressResponse; } Status Socks5::wait_ip_address_response() { CHECK(state_ == State::WaitIpAddressResponse); auto it = fd_.input_buffer().clone(); VLOG(proxy) << "Receive IP address response of size " << it.size(); if (it.size() < 4) { return Status::OK(); } char c; MutableSlice c_slice(&c, 1); it.advance(1, c_slice); if (c != '\x05') { return Status::Error("Invalid response"); } it.advance(1, c_slice); if (c != '\0') { return Status::Error(PSLICE() << "Receive error code " << static_cast<int32>(c) << " from server"); } it.advance(1, c_slice); if (c != '\0') { return Status::Error("Byte must be zero"); } it.advance(1, c_slice); size_t total_size = 6; if (c == '\x01') { if (it.size() < 4) { return Status::OK(); } it.advance(4); total_size += 4; } else if (c == '\x04') { if (it.size() < 16) { return Status::OK(); } it.advance(16); total_size += 16; } else { return Status::Error("Invalid response"); } if (it.size() < 2) { return Status::OK(); } it.advance(2); fd_.input_buffer().advance(total_size); stop(); return Status::OK(); } Status Socks5::loop_impl() { switch (state_) { case State::SendGreeting: send_greeting(); break; case State::WaitGreetingResponse: TRY_STATUS(wait_greeting_response()); break; case State::WaitPasswordResponse: TRY_STATUS(wait_password_response()); break; case State::WaitIpAddressResponse: TRY_STATUS(wait_ip_address_response()); break; default: UNREACHABLE(); } return Status::OK(); } } // namespace td