diff --git a/request.go b/request.go index c5b8613..08f9452 100644 --- a/request.go +++ b/request.go @@ -4,7 +4,9 @@ import ( "encoding/binary" "fmt" "io" + "log" "net" + "strings" ) const ( @@ -92,6 +94,9 @@ func (s *Server) handleRequest(conn net.Conn, bufConn io.Reader) error { case associateCommand: return s.handleAssociate(conn, bufConn, dest) default: + if err := sendReply(conn, commandNotSupported, nil); err != nil { + return fmt.Errorf("Failed to send reply: %v", err) + } return fmt.Errorf("Unsupported command: %v", header[1]) } } @@ -107,7 +112,39 @@ func (s *Server) handleConnect(conn net.Conn, bufConn io.Reader, dest *addrSpec) return fmt.Errorf("Connect to %v blocked by rules", dest) } - return nil + // Attempt to connect + addr := net.TCPAddr{IP: dest.ip, Port: dest.port} + target, err := net.DialTCP("tcp", nil, &addr) + 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, dest); err != nil { + return fmt.Errorf("Failed to send reply: %v", err) + } + return fmt.Errorf("Connect to %v failed: %v", dest, err) + } + defer target.Close() + + // Send success + if err := sendReply(conn, successReply, dest); err != nil { + return fmt.Errorf("Failed to send reply: %v", err) + } + + // Start proxying + errCh := make(chan error, 2) + go proxy("client", target, bufConn, errCh) + go proxy("target", conn, target, errCh) + + // Wait + select { + case e := <-errCh: + return e + } } // handleBind is used to handle a connect command @@ -121,6 +158,10 @@ func (s *Server) handleBind(conn net.Conn, bufConn io.Reader, dest *addrSpec) er return fmt.Errorf("Bind to %v blocked by rules", dest) } + // TODO: Support bind + if err := sendReply(conn, commandNotSupported, nil); err != nil { + return fmt.Errorf("Failed to send reply: %v", err) + } return nil } @@ -135,6 +176,10 @@ func (s *Server) handleAssociate(conn net.Conn, bufConn io.Reader, dest *addrSpe return fmt.Errorf("Associate to %v blocked by rules", dest) } + // TODO: Support associate + if err := sendReply(conn, commandNotSupported, nil); err != nil { + return fmt.Errorf("Failed to send reply: %v", err) + } return nil } @@ -229,3 +274,12 @@ func sendReply(w io.Writer, resp uint8, addr *addrSpec) error { _, err := w.Write(msg) return err } + +// proxy is used to suffle data from src to destination, and sends errors +// down a dedicated channel +func proxy(name string, dst io.WriteCloser, src io.Reader, errCh chan error) { + defer dst.Close() + n, err := io.Copy(dst, src) + errCh <- err + log.Printf("[DEBUG] Copied %d bytes for %s", n, name) +} diff --git a/socks5.go b/socks5.go index a6a6932..cb679ad 100644 --- a/socks5.go +++ b/socks5.go @@ -24,6 +24,9 @@ type Config struct { // Rules is provided to enable custom logic around permitting // various commands. If not provided, PermitAll is used. Rules RuleSet + + // BindIP is used for bind or udp associate + BindIP net.IP } // Server is reponsible for accepting connections and handling