Moved DoH/DoT/UDP configuration from command line to PT-compatible SOCKS CONNECT configuration.

dnstt-client/lib/client.go

@@ -119,10 +119,9 @@ func handle(local *net.TCPConn, sess *smux.Session, conv uint32) error {
 	return err
 }
 
-func acceptLoop(ln *pt.SocksListener, pconn net.PacketConn, remoteAddr net.Addr, shutdown chan struct{}, wg *sync.WaitGroup) {
+func acceptLoop(ln *pt.SocksListener, utlsClientHelloID *utls.ClientHelloID, shutdown chan struct{}, wg *sync.WaitGroup) {
 	defer func() {
 		_ = ln.Close()
-		_ = pconn.Close()
 	}()
 
 	for {
@@ -146,6 +145,57 @@ func acceptLoop(ln *pt.SocksListener, pconn net.PacketConn, remoteAddr net.Addr,
 			}()
 
 			var pubkey []byte
+			var remoteAddr net.Addr
+			var pconn net.PacketConn
+			var err error
+
+			if arg, ok := local.Req.Args.Get("doh"); ok {
+				remoteAddr = turbotunnel.DummyAddr{}
+				var rt http.RoundTripper
+				if utlsClientHelloID == nil {
+					transport := http.DefaultTransport.(*http.Transport).Clone()
+					// Disable DefaultTransport's default Proxy =
+					// ProxyFromEnvironment setting, for conformity
+					// with utlsRoundTripper and with DoT mode,
+					// which do not take a proxy from the
+					// environment.
+					transport.Proxy = nil
+					rt = transport
+				} else {
+					rt = NewUTLSRoundTripper(nil, utlsClientHelloID)
+				}
+				pconn, err = NewHTTPPacketConn(rt, arg, 32)
+
+			} else if arg, ok := local.Req.Args.Get("dot"); ok {
+				remoteAddr = turbotunnel.DummyAddr{}
+				var dialTLSContext func(ctx context.Context, network, addr string) (net.Conn, error)
+				if utlsClientHelloID == nil {
+					dialTLSContext = (&tls.Dialer{}).DialContext
+				} else {
+					dialTLSContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+						return utlsDialContext(ctx, network, addr, nil, utlsClientHelloID)
+					}
+				}
+				pconn, err = NewTLSPacketConn(arg, dialTLSContext)
+
+			} else if arg, ok := local.Req.Args.Get("udp"); ok {
+				remoteAddr, err = net.ResolveUDPAddr("udp", arg)
+				if err == nil {
+					pconn, err = net.ListenUDP("udp", nil)
+				}
+			}
+
+			if err != nil {
+				log.Printf("DNS server error: %v\n", err)
+				_ = local.Reject()
+				return
+			}
+
+			if remoteAddr == nil || pconn == nil {
+				log.Printf("Missing DNS server. Use 'doh', 'dot' or 'udp' argument to provide one!")
+				_ = local.Reject()
+				return
+			}
 
 			if arg, ok := local.Req.Args.Get("pubkey"); ok {
 				pubkey, err = noise.DecodeKey(arg)
@@ -279,7 +329,7 @@ func acceptLoop(ln *pt.SocksListener, pconn net.PacketConn, remoteAddr net.Addr,
 	}
 }
 
-func Start(dohURL, dotAddr, udpAddr, listenAddr string, utlsClientHelloID *utls.ClientHelloID) {
+func Start(listenAddr string, utlsClientHelloID *utls.ClientHelloID) {
 
 	if listenAddr == "" {
 		listenAddr = "127.0.0.1:0"
@@ -296,76 +346,6 @@ func Start(dohURL, dotAddr, udpAddr, listenAddr string, utlsClientHelloID *utls.
 		log.Printf("uTLS fingerprint %s %s", utlsClientHelloID.Client, utlsClientHelloID.Version)
 	}
 
-	// Iterate over the remote resolver address options and select one and
-	// only one.
-	var remoteAddr net.Addr
-	var pconn net.PacketConn
-	for _, opt := range []struct {
-		s string
-		f func(string) (net.Addr, net.PacketConn, error)
-	}{
-		// -doh
-		{dohURL, func(s string) (net.Addr, net.PacketConn, error) {
-			addr := turbotunnel.DummyAddr{}
-			var rt http.RoundTripper
-			if utlsClientHelloID == nil {
-				transport := http.DefaultTransport.(*http.Transport).Clone()
-				// Disable DefaultTransport's default Proxy =
-				// ProxyFromEnvironment setting, for conformity
-				// with utlsRoundTripper and with DoT mode,
-				// which do not take a proxy from the
-				// environment.
-				transport.Proxy = nil
-				rt = transport
-			} else {
-				rt = NewUTLSRoundTripper(nil, utlsClientHelloID)
-			}
-			pconn, err := NewHTTPPacketConn(rt, dohURL, 32)
-			return addr, pconn, err
-		}},
-		// -dot
-		{dotAddr, func(s string) (net.Addr, net.PacketConn, error) {
-			addr := turbotunnel.DummyAddr{}
-			var dialTLSContext func(ctx context.Context, network, addr string) (net.Conn, error)
-			if utlsClientHelloID == nil {
-				dialTLSContext = (&tls.Dialer{}).DialContext
-			} else {
-				dialTLSContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
-					return utlsDialContext(ctx, network, addr, nil, utlsClientHelloID)
-				}
-			}
-			pconn, err := NewTLSPacketConn(dotAddr, dialTLSContext)
-			return addr, pconn, err
-		}},
-		// -udp
-		{udpAddr, func(s string) (net.Addr, net.PacketConn, error) {
-			addr, err := net.ResolveUDPAddr("udp", s)
-			if err != nil {
-				return nil, nil, err
-			}
-			pconn, err := net.ListenUDP("udp", nil)
-			return addr, pconn, err
-		}},
-	} {
-		if opt.s == "" {
-			continue
-		}
-		if pconn != nil {
-			log.Printf("only one of -doh, -dot, and -udp may be given\n")
-			return
-		}
-		var err error
-		remoteAddr, pconn, err = opt.f(opt.s)
-		if err != nil {
-			log.Print(err)
-			return
-		}
-	}
-	if pconn == nil {
-		log.Printf("one of -doh, -dot, or -udp is required\n")
-		return
-	}
-
 	// Begin goptlib client process.
 	ptInfo, err := pt.ClientSetup(nil)
 	if err != nil {
@@ -392,7 +372,7 @@ func Start(dohURL, dotAddr, udpAddr, listenAddr string, utlsClientHelloID *utls.
 				break
 			}
 
-			go acceptLoop(ln, pconn, remoteAddr, shutdown, &wg)
+			go acceptLoop(ln, utlsClientHelloID, shutdown, &wg)
 
 			pt.Cmethod(methodName, ln.Version(), ln.Addr())
 			listeners = append(listeners, ln)

dnstt-client/main.go

@@ -39,18 +39,11 @@ import (
 )
 
 func main() {
-	var dohURL string
-	var dotAddr string
-	var udpAddr string
 	var utlsDistribution string
 
 	flag.Usage = func() {
 		_, _ = fmt.Fprintf(flag.CommandLine.Output(), `Usage:
-  %[1]s [-doh URL|-dot ADDR|-udp ADDR]
-
-Examples:
-  %[1]s -doh https://resolver.example/dns-query t.example.com
-  %[1]s -dot resolver.example:853 t.example.com
+  %[1]s [-utls FINGERPRINTS]
 
 `, os.Args[0])
 		flag.PrintDefaults()
@@ -76,9 +69,6 @@ Known TLS fingerprints for -utls are:
 			_, _ = fmt.Fprintln(flag.CommandLine.Output(), line.String())
 		}
 	}
-	flag.StringVar(&dohURL, "doh", "", "URL of DoH resolver")
-	flag.StringVar(&dotAddr, "dot", "", "address of DoT resolver")
-	flag.StringVar(&udpAddr, "udp", "", "address of UDP DNS resolver")
 	flag.StringVar(&utlsDistribution, "utls",
 		"3*Firefox_65,1*Firefox_63,1*iOS_12_1",
 		"choose TLS fingerprint from weighted distribution")
@@ -95,5 +85,5 @@ Known TLS fingerprints for -utls are:
 		os.Exit(1)
 	}
 
-	dc.Start(dohURL, dotAddr, udpAddr, "", utlsClientHelloID)
+	dc.Start("", utlsClientHelloID)
 }