AUTH-2394 added socks5 proxy

socks/request_handler.go

@@ -0,0 +1,106 @@
+package socks
+
+import (
+	"fmt"
+	"io"
+	"strings"
+)
+
+// RequestHandler is the functions needed to handle a SOCKS5 command
+type RequestHandler interface {
+	Handle(*Request, io.ReadWriter) error
+}
+
+// StandardRequestHandler implements the base socks5 command processing
+type StandardRequestHandler struct {
+	dialer Dialer
+}
+
+// NewRequestHandler creates a standard SOCKS5 request handler
+// This handles the SOCKS5 commands and proxies them to their destination
+func NewRequestHandler(dialer Dialer) RequestHandler {
+	return &StandardRequestHandler{
+		dialer: dialer,
+	}
+}
+
+// Handle processes and responds to socks5 commands
+func (h *StandardRequestHandler) Handle(req *Request, conn io.ReadWriter) error {
+	switch req.Command {
+	case connectCommand:
+		return h.handleConnect(conn, req)
+	case bindCommand:
+		return h.handleBind(conn, req)
+	case associateCommand:
+		return h.handleAssociate(conn, req)
+	default:
+		if err := sendReply(conn, commandNotSupported, nil); err != nil {
+			return fmt.Errorf("Failed to send reply: %v", err)
+		}
+		return fmt.Errorf("Unsupported command: %v", req.Command)
+	}
+}
+
+// handleConnect is used to handle a connect command
+func (h *StandardRequestHandler) handleConnect(conn io.ReadWriter, req *Request) error {
+	target, localAddr, err := h.dialer.Dial(req.DestAddr.Address())
+	if err != nil {
+		msg := err.Error()
+		resp := hostUnreachable
+		if strings.Contains(msg, "refused") {
+			resp = connectionRefused
+		} else if strings.Contains(msg, "network is unreachable") {
+			resp = networkUnreachable
+		}
+		if err := sendReply(conn, resp, nil); err != nil {
+			return fmt.Errorf("Failed to send reply: %v", err)
+		}
+		return fmt.Errorf("Connect to %v failed: %v", req.DestAddr, err)
+	}
+	defer target.Close()
+
+	// Send success
+	if err := sendReply(conn, successReply, localAddr); err != nil {
+		return fmt.Errorf("Failed to send reply: %v", err)
+	}
+
+	// Start proxying
+	proxyDone := make(chan error, 2)
+
+	go func() {
+		_, e := io.Copy(target, req.bufConn)
+		proxyDone <- e
+	}()
+
+	go func() {
+		_, e := io.Copy(conn, target)
+		proxyDone <- e
+	}()
+
+	// Wait for both
+	for i := 0; i < 2; i++ {
+		e := <-proxyDone
+		if e != nil {
+			return e
+		}
+	}
+	return nil
+}
+
+// handleBind is used to handle a bind command
+// TODO: Support bind command
+func (h *StandardRequestHandler) handleBind(conn io.ReadWriter, req *Request) error {
+	if err := sendReply(conn, commandNotSupported, nil); err != nil {
+		return fmt.Errorf("Failed to send reply: %v", err)
+	}
+	return nil
+}
+
+// handleAssociate is used to handle a connect command
+// TODO: Support associate command
+func (h *StandardRequestHandler) handleAssociate(conn io.ReadWriter, req *Request) error {
+	if err := sendReply(conn, commandNotSupported, nil); err != nil {
+		return fmt.Errorf("Failed to send reply: %v", err)
+	}
+	return nil
+}