I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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/*
* Copyright (c) 2024, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*
*/
#ifndef SOCKS5_H__
#define SOCKS5_H__
#include <string>
#include <memory>
#include <boost/asio.hpp>
#include "I2PEndian.h"
namespace i2p
{
namespace transport
{
// SOCKS5 constants
const uint8_t SOCKS5_VER = 0x05;
const uint8_t SOCKS5_CMD_CONNECT = 0x01;
const uint8_t SOCKS5_CMD_UDP_ASSOCIATE = 0x03;
const uint8_t SOCKS5_ATYP_IPV4 = 0x01;
const uint8_t SOCKS5_ATYP_IPV6 = 0x04;
const uint8_t SOCKS5_ATYP_NAME = 0x03;
const size_t SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE = 10;
const size_t SOCKS5_UDP_IPV6_REQUEST_HEADER_SIZE = 22;
const uint8_t SOCKS5_REPLY_SUCCESS = 0x00;
const uint8_t SOCKS5_REPLY_SERVER_FAILURE = 0x01;
const uint8_t SOCKS5_REPLY_CONNECTION_NOT_ALLOWED = 0x02;
const uint8_t SOCKS5_REPLY_NETWORK_UNREACHABLE = 0x03;
const uint8_t SOCKS5_REPLY_HOST_UNREACHABLE = 0x04;
const uint8_t SOCKS5_REPLY_CONNECTION_REFUSED = 0x05;
const uint8_t SOCKS5_REPLY_TTL_EXPIRED = 0x06;
const uint8_t SOCKS5_REPLY_COMMAND_NOT_SUPPORTED = 0x07;
const uint8_t SOCKS5_REPLY_ADDRESS_TYPE_NOT_SUPPORTED = 0x08;
// SOCKS5 handshake
template<typename Socket, typename Handler>
void Socks5ReadReply (Socket& s, Handler handler)
{
auto readbuff = std::make_shared<std::vector<int8_t> >(258); // max possible
boost::asio::async_read(s, boost::asio::buffer(readbuff->data (), 5), boost::asio::transfer_all(), // read 4 bytes of header + first byte of address
[readbuff, &s, handler](const boost::system::error_code& ec, std::size_t transferred)
{
if (!ec)
{
if ((*readbuff)[1] == SOCKS5_REPLY_SUCCESS)
{
size_t len = 0;
switch ((*readbuff)[3]) // ATYP
{
case SOCKS5_ATYP_IPV4: len = 3; break; // address length 4 bytes
case SOCKS5_ATYP_IPV6: len = 15; break; // address length 16 bytes
case SOCKS5_ATYP_NAME: len += (*readbuff)[4]; break; // first byte of address is length
default: ;
}
if (len)
{
len += 2; // port
boost::asio::async_read(s, boost::asio::buffer(readbuff->data (), len), boost::asio::transfer_all(),
[readbuff, &s, handler](const boost::system::error_code& ec, std::size_t transferred)
{
if (!ec)
handler (boost::system::error_code ()); // success
else
handler (boost::asio::error::make_error_code (boost::asio::error::connection_aborted));
});
}
else
handler (boost::asio::error::make_error_code (boost::asio::error::fault)); // unknown address type
}
else
switch ((*readbuff)[1]) // REP
{
case SOCKS5_REPLY_SERVER_FAILURE:
handler (boost::asio::error::make_error_code (boost::asio::error::access_denied ));
break;
case SOCKS5_REPLY_CONNECTION_NOT_ALLOWED:
handler (boost::asio::error::make_error_code (boost::asio::error::no_permission));
break;
case SOCKS5_REPLY_HOST_UNREACHABLE:
handler (boost::asio::error::make_error_code (boost::asio::error::host_unreachable));
break;
case SOCKS5_REPLY_NETWORK_UNREACHABLE:
handler (boost::asio::error::make_error_code (boost::asio::error::network_unreachable));
break;
case SOCKS5_REPLY_CONNECTION_REFUSED:
handler (boost::asio::error::make_error_code (boost::asio::error::connection_refused));
break;
case SOCKS5_REPLY_TTL_EXPIRED:
handler (boost::asio::error::make_error_code (boost::asio::error::timed_out));
break;
case SOCKS5_REPLY_COMMAND_NOT_SUPPORTED:
handler (boost::asio::error::make_error_code (boost::asio::error::operation_not_supported));
break;
case SOCKS5_REPLY_ADDRESS_TYPE_NOT_SUPPORTED:
handler (boost::asio::error::make_error_code (boost::asio::error::no_protocol_option));
break;
default:
handler (boost::asio::error::make_error_code (boost::asio::error::connection_aborted));
}
}
else
handler (ec);
});
}
template<typename Socket, typename Handler>
void Socks5Connect (Socket& s, Handler handler, std::shared_ptr<std::vector<uint8_t> > buff, uint16_t port)
{
if (buff && buff->size () >= 6)
{
(*buff)[0] = SOCKS5_VER;
(*buff)[1] = SOCKS5_CMD_CONNECT;
(*buff)[2] = 0x00;
htobe16buf(buff->data () + buff->size () - 2, port);
boost::asio::async_write(s, boost::asio::buffer(*buff), boost::asio::transfer_all(),
[buff, &s, handler](const boost::system::error_code& ec, std::size_t transferred)
{
(void) transferred;
if (!ec)
Socks5ReadReply (s, handler);
else
handler (ec);
});
}
else
handler (boost::asio::error::make_error_code (boost::asio::error::no_buffer_space));
}
template<typename Socket, typename Handler>
void Socks5Connect (Socket& s, const boost::asio::ip::tcp::endpoint& ep, Handler handler)
{
std::shared_ptr<std::vector<uint8_t> > buff;
if(ep.address ().is_v4 ())
{
buff = std::make_shared<std::vector<uint8_t> >(10);
(*buff)[3] = SOCKS5_ATYP_IPV4;
auto addrbytes = ep.address ().to_v4().to_bytes();
memcpy(buff->data () + 4, addrbytes.data(), 4);
}
else if (ep.address ().is_v6 ())
{
buff = std::make_shared<std::vector<uint8_t> >(22);
(*buff)[3] = SOCKS5_ATYP_IPV6;
auto addrbytes = ep.address ().to_v6().to_bytes();
memcpy(buff->data () + 4, addrbytes.data(), 16);
}
if (buff)
Socks5Connect (s, handler, buff, ep.port ());
else
handler (boost::asio::error::make_error_code (boost::asio::error::fault));
}
template<typename Socket, typename Handler>
void Socks5Connect (Socket& s, const std::pair<std::string, uint16_t>& ep, Handler handler)
{
auto& addr = ep.first;
if (addr.length () <= 255)
{
auto buff = std::make_shared<std::vector<uint8_t> >(addr.length () + 7);
(*buff)[3] = SOCKS5_ATYP_NAME;
(*buff)[4] = addr.length ();
memcpy (buff->data () + 5, addr.c_str (), addr.length ());
Socks5Connect (s, handler, buff, ep.second);
}
else
handler (boost::asio::error::make_error_code (boost::asio::error::name_too_long));
}
template<typename Socket, typename Endpoint, typename Handler>
void Socks5Handshake (Socket& s, Endpoint ep, Handler handler)
{
static const uint8_t methodSelection[3] = { SOCKS5_VER, 0x01, 0x00 }; // 1 method, no auth
boost::asio::async_write(s, boost::asio::buffer(methodSelection, 3), boost::asio::transfer_all(),
[&s, ep, handler] (const boost::system::error_code& ec, std::size_t transferred)
{
(void) transferred;
if (!ec)
{
auto readbuff = std::make_shared<std::vector<uint8_t> >(2);
boost::asio::async_read(s, boost::asio::buffer(*readbuff), boost::asio::transfer_all(),
[&s, ep, handler, readbuff] (const boost::system::error_code& ec, std::size_t transferred)
{
if (!ec)
{
if (transferred == 2 && (*readbuff)[1] == 0x00) // no auth
Socks5Connect (s, ep, handler);
else
handler (boost::asio::error::make_error_code (boost::asio::error::invalid_argument));
}
else
handler (ec);
});
}
else
handler (ec);
});
}
}
}
#endif