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