asio-socks45-client

SOCKS4 and SOCKS5 clients for (Boost) Asio

Originally authored in response to StaockOverflow questions:

• SOCKS4 With Boost Asio
• Is there a native support for proxy connection via socks5 for boost::asio?

The interfaces are sync/async, with a shared underlying implementation.

SOCK4 Usage

tcp::socket sock{ctx};
tcp::endpoint
    proxy{{}, 1080},
    target{ip::make_address("173.203.57.63"), 80};

std::cerr << "Using synchronous interface" << std::endl;
socks4::proxy_connect(sock, target,
                      proxy); // throws system_error if failed

Or using the async overload:

// using the async interface (still emulating synchronous by using
// future for brevity of this demo)
auto fut = socks4::async_proxy_connect(sock, target, proxy,
                                       boost::asio::use_future);

fut.get(); // throws system_error if failed

SOCKS4a (which also allows name resolution) is not implemented. There seems to be little support.

SOCKS5 Usage

The SOCKS5 interface accepts a qualified domain name as well as resolved end-point.

socks5::TargetSpec target("example.com", 443);

std::future<void> conn_result = socks5::async_proxy_connect(
    socket, target, tcp::endpoint{{}, 1080}, ba::use_future);

Again, synchronous connect is also supported:

socks5::proxy_connect(socket, target, tcp::endpoint{{}, 1080});

The BIND and UDP ASSOCIATE commands are not implemented.

DEMO

The answers show live demos. Here's a parallel demo of all SOCKS4 and SOCKS5 example programs demo using an openssh client as the SOCKS server: