int socks_connection::format_response(asio::ip::tcp::endpoint const& ep
, int response)
{
int i = 0;
if (m_version == 5)
{
// +----+-----+-------+------+----------+----------+
// |VER | REP | RSV | ATYP | BND.ADDR | BND.PORT |
// +----+-----+-------+------+----------+----------+
// | 1 | 1 | X'00' | 1 | Variable | 2 |
// +----+-----+-------+------+----------+----------+
m_in_buffer[i++] = m_version; // version
m_in_buffer[i++] = response; // response
m_in_buffer[i++] = 0; // reserved
if (ep.address().is_v4())
{
m_in_buffer[i++] = 1; // IPv4
address_v4::bytes_type b = ep.address().to_v4().to_bytes();
memcpy(&m_in_buffer[i], &b[0], b.size());
i += b.size();
} else {
m_in_buffer[i++] = 4; // IPv6
address_v6::bytes_type b = ep.address().to_v6().to_bytes();
memcpy(&m_in_buffer[i], &b[0], b.size());
i += b.size();
}
m_in_buffer[i++] = ep.port() >> 8;
m_in_buffer[i++] = ep.port() & 0xff;
}
void socks_connection::bind_connection(asio::ip::tcp::endpoint target)
{
printf("socks_connection::bind_connection(%s): binding to %s port %d\n"
, command(), target.address().to_string().c_str(), target.port());
error_code ec;
m_bind_socket.open(target.protocol(), ec);
if (ec)
{
printf("ERROR: open bind socket failed: (%d) %s\n", ec.value()
, ec.message().c_str());
}
else
{
m_bind_socket.bind(target, ec);
}
int const response = ec
? (m_version == 4 ? 91 : 1)
: (m_version == 4 ? 90 : 0);
int const len = format_response(
m_bind_socket.local_endpoint(), response);
if (ec)
{
printf("ERROR: binding socket to %s %d failed: (%d) %s\n"
, target.address().to_string().c_str()
, target.port()
, ec.value()
, ec.message().c_str());
auto self = shared_from_this();
asio::async_write(m_client_connection
, asio::const_buffers_1(&m_in_buffer[0], len)
, [=](boost::system::error_code const& ec, size_t)
{
self->close_connection();
});
return;
}
// send response
asio::async_write(m_client_connection
, asio::const_buffers_1(&m_in_buffer[0], len)
, std::bind(&socks_connection::start_accept, shared_from_this(), _1));
}
void socks_connection::open_forward_connection(asio::ip::tcp::endpoint target)
{
printf("socks_connection::open_forward_connection(%s): connecting to %s port %d\n"
, command(), target.address().to_string().c_str(), target.port());
m_server_connection.open(target.protocol());
m_server_connection.async_connect(target
, std::bind(&socks_connection::on_connected, shared_from_this()
, _1));
}