Add option for ICE servers to be client only (#3164)

* Add option for ICE servers to be client only

* add clientOnly to configuration file and API docs

---------

Co-authored-by: aler9 <46489434+aler9@users.noreply.github.com>

README.md

@@ -1879,6 +1879,16 @@ webrtcICEServers2:
 
 where secret is the secret of the TURN server. MediaMTX will generate a set of credentials by using the secret, and credentials will be sent to clients before the WebRTC/ICE connection is established.
 
+In some cases you may want the browser to connect using TURN servers but have mediamtx not using TURN (for example if the TURN server is on the same network as mediamtx).  To allow this you can configure the TURN server to be client only:
+
+```yml
+webrtcICEServers2:
+- url: turn:host:port
+  username: user
+  password: password
+  clientOnly: true
+```
+
 ### RTSP-specific features
 
 #### Transport protocols

apidocs/openapi.yaml

@@ -190,6 +190,8 @@ components:
                 type: string
               password:
                 type: string
+              clientOnly:
+                type: boolean
 
         # SRT server
         srt:

internal/conf/webrtc_ice_server.go

@@ -2,7 +2,8 @@ package conf
 
 // WebRTCICEServer is a WebRTC ICE Server.
 type WebRTCICEServer struct {
-	URL      string `json:"url"`
-	Username string `json:"username"`
-	Password string `json:"password"`
+	URL        string `json:"url"`
+	Username   string `json:"username"`
+	Password   string `json:"password"`
+	ClientOnly bool   `json:"clientOnly"`
 }

internal/servers/webrtc/http_server.go

@@ -151,7 +151,7 @@ func (s *httpServer) onWHIPOptions(ctx *gin.Context, path string, publish bool)
 		return
 	}
 
-	servers, err := s.parent.generateICEServers()
+	servers, err := s.parent.generateICEServers(true)
 	if err != nil {
 		writeError(ctx, http.StatusInternalServerError, err)
 		return
@@ -191,7 +191,7 @@ func (s *httpServer) onWHIPPost(ctx *gin.Context, path string, publish bool) {
 		return
 	}
 
-	servers, err := s.parent.generateICEServers()
+	servers, err := s.parent.generateICEServers(true)
 	if err != nil {
 		writeError(ctx, http.StatusInternalServerError, err)
 		return

internal/servers/webrtc/server.go

@@ -429,30 +429,32 @@ func (s *Server) findSessionByUUID(uuid uuid.UUID) *session {
 	return nil
 }
 
-func (s *Server) generateICEServers() ([]pwebrtc.ICEServer, error) {
-	ret := make([]pwebrtc.ICEServer, len(s.ICEServers))
+func (s *Server) generateICEServers(clientConfig bool) ([]pwebrtc.ICEServer, error) {
+	ret := make([]pwebrtc.ICEServer, 0, len(s.ICEServers))
 
-	for i, server := range s.ICEServers {
-		if server.Username == "AUTH_SECRET" {
-			expireDate := time.Now().Add(webrtcTurnSecretExpiration).Unix()
+	for _, server := range s.ICEServers {
+		if !server.ClientOnly || clientConfig {
+			if server.Username == "AUTH_SECRET" {
+				expireDate := time.Now().Add(webrtcTurnSecretExpiration).Unix()
 
-			user, err := randomTurnUser()
-			if err != nil {
-				return nil, err
+				user, err := randomTurnUser()
+				if err != nil {
+					return nil, err
+				}
+
+				server.Username = strconv.FormatInt(expireDate, 10) + ":" + user
+
+				h := hmac.New(sha1.New, []byte(server.Password))
+				h.Write([]byte(server.Username))
+
+				server.Password = base64.StdEncoding.EncodeToString(h.Sum(nil))
 			}
 
-			server.Username = strconv.FormatInt(expireDate, 10) + ":" + user
-
-			h := hmac.New(sha1.New, []byte(server.Password))
-			h.Write([]byte(server.Username))
-
-			server.Password = base64.StdEncoding.EncodeToString(h.Sum(nil))
-		}
-
-		ret[i] = pwebrtc.ICEServer{
-			URLs:       []string{server.URL},
-			Username:   server.Username,
-			Credential: server.Password,
+			ret = append(ret, pwebrtc.ICEServer{
+				URLs:       []string{server.URL},
+				Username:   server.Username,
+				Credential: server.Password,
+			})
 		}
 	}
 

internal/servers/webrtc/server_test.go

@@ -408,3 +408,40 @@ func TestServerReadNotFound(t *testing.T) {
 
 	require.Equal(t, http.StatusNotFound, res.StatusCode)
 }
+
+func TestICEServerNoClientOnly(t *testing.T) {
+	s := &Server{
+		ICEServers: []conf.WebRTCICEServer{
+			{
+				URL:      "turn:turn.example.com:1234",
+				Username: "user",
+				Password: "passwrd",
+			},
+		},
+	}
+	clientICEServers, err := s.generateICEServers(true)
+	require.NoError(t, err)
+	require.Equal(t, len(s.ICEServers), len(clientICEServers))
+	serverICEServers, err := s.generateICEServers(false)
+	require.NoError(t, err)
+	require.Equal(t, len(s.ICEServers), len(serverICEServers))
+}
+
+func TestICEServerClientOnly(t *testing.T) {
+	s := &Server{
+		ICEServers: []conf.WebRTCICEServer{
+			{
+				URL:        "turn:turn.example.com:1234",
+				Username:   "user",
+				Password:   "passwrd",
+				ClientOnly: true,
+			},
+		},
+	}
+	clientICEServers, err := s.generateICEServers(true)
+	require.NoError(t, err)
+	require.Equal(t, len(s.ICEServers), len(clientICEServers))
+	serverICEServers, err := s.generateICEServers(false)
+	require.NoError(t, err)
+	require.Equal(t, 0, len(serverICEServers))
+}

internal/servers/webrtc/session.go

@@ -393,7 +393,7 @@ func (s *session) runPublish() (int, error) {
 
 	defer path.RemovePublisher(defs.PathRemovePublisherReq{Author: s})
 
-	iceServers, err := s.parent.generateICEServers()
+	iceServers, err := s.parent.generateICEServers(false)
 	if err != nil {
 		return http.StatusInternalServerError, err
 	}
@@ -528,7 +528,7 @@ func (s *session) runRead() (int, error) {
 
 	defer path.RemoveReader(defs.PathRemoveReaderReq{Author: s})
 
-	iceServers, err := s.parent.generateICEServers()
+	iceServers, err := s.parent.generateICEServers(false)
 	if err != nil {
 		return http.StatusInternalServerError, err
 	}

mediamtx.yml

@@ -311,6 +311,7 @@ webrtcICEServers2: []
   # the secret must be inserted into the password field.
   # username: ''
   # password: ''
+  # clientOnly: false
 
 ###############################################
 # Global settings -> SRT server