socks5

SOCKS5 client and server. Full test coverage provided by https://github.com/linkdata/socks5test.

• Support for the CONNECT command
• Support for the BIND command
• Support for the ASSOCIATE command
• Uses ContextDialer's for easy interoperation with other packages
• Only depends on the standard library

Client

The client support for net.Listener includes reporting the bound address and port before calling Accept() and supports multiple concurrent Accept() calls, allowing you to reverse-proxy a server using this package.

Server

The server can listen on multiple listeners concurrently.

The server provides two abstractions to customize it's behavior.

The Authenticator interface allows custom authentication methods, and comes with implementations for anonymous usage (NoAuthAuthenticator) or username/password authentication (UserPassAuthenticator).

The DialerSelector interface allows selecting the ContextDialer to use for each outgoing connection based on authentication method, username, network and address. The default uses socks5.DefaultDialer.

Example

package main

import (
	"context"
	"errors"
	"log/slog"
	"net"
	"time"

	"github.com/linkdata/socks5/client"
	"github.com/linkdata/socks5/server"
)

func main() {
	ctx, cancel := context.WithTimeout(context.Background(), time.Second/10)
	defer cancel()

	listener, err := net.Listen("tcp", ":0")
	if err == nil {
		defer listener.Close()
		srv := server.Server{
			Logger: slog.Default(),
			Authenticators: []server.Authenticator{
				server.NoAuthAuthenticator{},
				server.UserPassAuthenticator{
					Credentials: server.StaticCredentials{
						"joe": "123456",
					},
				},
			},
		}
		go srv.Serve(ctx, listener)
		var cli *client.Client
		if cli, err = client.New("socks5h://joe:123456@" + listener.Addr().String()); err == nil {
			var l net.Listener
			if l, err = cli.ListenContext(ctx, "tcp", ":0"); err == nil {
				defer l.Close()
				slog.Info("client BIND", "address", l.Addr().String())
			}
		}
	}
	if err != nil && !errors.Is(err, context.DeadlineExceeded) {
		slog.Error("failed", "error", err)
	}
}