AUTH-2394 added socks5 proxy

socks/connection_handler.go

@@ -0,0 +1,57 @@
+package socks
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+)
+
+// ConnectionHandler is the Serve method to handle connections
+// from a local TCP listener of the standard library (net.Listener)
+type ConnectionHandler interface {
+	Serve(io.ReadWriter) error
+}
+
+// StandardConnectionHandler is the base implementation of handling SOCKS5 requests
+type StandardConnectionHandler struct {
+	requestHandler RequestHandler
+	authHandler    AuthHandler
+}
+
+// NewConnectionHandler creates a standard SOCKS5 connection handler
+// This process connections from a generic TCP listener from the standard library
+func NewConnectionHandler(requestHandler RequestHandler) ConnectionHandler {
+	return &StandardConnectionHandler{
+		requestHandler: requestHandler,
+		authHandler:    NewAuthHandler(),
+	}
+}
+
+// Serve process new connection created after calling `Accept()` in the standard library
+func (h *StandardConnectionHandler) Serve(c io.ReadWriter) error {
+	bufConn := bufio.NewReader(c)
+
+	// read the version byte
+	version := []byte{0}
+	if _, err := bufConn.Read(version); err != nil {
+		return err
+	}
+
+	// ensure compatibility
+	if version[0] != socks5Version {
+		return fmt.Errorf("Unsupported SOCKS version: %v", version)
+	}
+
+	// handle auth
+	if err := h.authHandler.Handle(bufConn, c); err != nil {
+		return err
+	}
+
+	// process command/request
+	req, err := NewRequest(bufConn)
+	if err != nil {
+		return err
+	}
+
+	return h.requestHandler.Handle(req, c)
+}