Pass nil candidate into pion/ice

Pass empty string candidate.Candidate into pion/ice to handle.

Co-authored-by: JooYoung <[email protected]>

Resolves #1212

icetransport.go

@@ -234,8 +234,8 @@ func (t *ICETransport) SetRemoteCandidates(remoteCandidates []ICECandidate) erro
 		if err != nil {
 			return err
 		}
-		err = agent.AddRemoteCandidate(i)
-		if err != nil {
+
+		if err = agent.AddRemoteCandidate(i); err != nil {
 			return err
 		}
 	}
@@ -244,30 +244,31 @@ func (t *ICETransport) SetRemoteCandidates(remoteCandidates []ICECandidate) erro
 }
 
 // AddRemoteCandidate adds a candidate associated with the remote ICETransport.
-func (t *ICETransport) AddRemoteCandidate(remoteCandidate ICECandidate) error {
+func (t *ICETransport) AddRemoteCandidate(remoteCandidate *ICECandidate) error {
 	t.lock.RLock()
 	defer t.lock.RUnlock()
 
-	if err := t.ensureGatherer(); err != nil {
+	var (
+		c   ice.Candidate
+		err error
+	)
+
+	if err = t.ensureGatherer(); err != nil {
 		return err
 	}
 
-	c, err := remoteCandidate.toICE()
-	if err != nil {
-		return err
+	if remoteCandidate != nil {
+		if c, err = remoteCandidate.toICE(); err != nil {
+			return err
+		}
 	}
 
 	agent := t.gatherer.getAgent()
 	if agent == nil {
 		return fmt.Errorf("%w: unable to add remote candidates", errICEAgentNotExist)
 	}
 
-	err = agent.AddRemoteCandidate(c)
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return agent.AddRemoteCandidate(c)
 }
 
 // State returns the current ice transport state.

peerconnection.go

@@ -1053,8 +1053,8 @@ func (pc *PeerConnection) SetRemoteDescription(desc SessionDescription) error {
 		}
 	}
 
-	for _, c := range candidates {
-		if err = pc.iceTransport.AddRemoteCandidate(c); err != nil {
+	for i := range candidates {
+		if err = pc.iceTransport.AddRemoteCandidate(&candidates[i]); err != nil {
 			return err
 		}
 	}
@@ -1454,21 +1454,26 @@ func (pc *PeerConnection) RemoteDescription() *SessionDescription {
 }
 
 // AddICECandidate accepts an ICE candidate string and adds it
-// to the existing set of candidates
+// to the existing set of candidates.
 func (pc *PeerConnection) AddICECandidate(candidate ICECandidateInit) error {
 	if pc.RemoteDescription() == nil {
 		return &rtcerr.InvalidStateError{Err: ErrNoRemoteDescription}
 	}
 
 	candidateValue := strings.TrimPrefix(candidate.Candidate, "candidate:")
-	c, err := ice.UnmarshalCandidate(candidateValue)
-	if err != nil {
-		return err
-	}
 
-	iceCandidate, err := newICECandidateFromICE(c)
-	if err != nil {
-		return err
+	var iceCandidate *ICECandidate
+	if candidateValue != "" {
+		candidate, err := ice.UnmarshalCandidate(candidateValue)
+		if err != nil {
+			return err
+		}
+
+		c, err := newICECandidateFromICE(candidate)
+		if err != nil {
+			return err
+		}
+		iceCandidate = &c
 	}
 
 	return pc.iceTransport.AddRemoteCandidate(iceCandidate)

peerconnection_go_test.go

@@ -1158,3 +1158,40 @@ func TestPeerConnection_MassiveTracks(t *testing.T) {
 	assert.NoError(t, offerPC.Close())
 	assert.NoError(t, answerPC.Close())
 }
+
+func TestEmptyCandidate(t *testing.T) {
+	testCases := []struct {
+		ICECandidate ICECandidateInit
+		expectError  bool
+	}{
+		{ICECandidateInit{"", nil, nil, nil}, false},
+		{ICECandidateInit{
+			"211962667 1 udp 2122194687 10.0.3.1 40864 typ host generation 0",
+			nil, nil, nil,
+		}, false},
+		{ICECandidateInit{
+			"1234567",
+			nil, nil, nil,
+		}, true},
+	}
+
+	for i, testCase := range testCases {
+		peerConn, err := NewPeerConnection(Configuration{})
+		if err != nil {
+			t.Errorf("Case %d: got error: %v", i, err)
+		}
+
+		err = peerConn.SetRemoteDescription(SessionDescription{Type: SDPTypeOffer, SDP: minimalOffer})
+		if err != nil {
+			t.Errorf("Case %d: got error: %v", i, err)
+		}
+
+		if testCase.expectError {
+			assert.Error(t, peerConn.AddICECandidate(testCase.ICECandidate))
+		} else {
+			assert.NoError(t, peerConn.AddICECandidate(testCase.ICECandidate))
+		}
+
+		assert.NoError(t, peerConn.Close())
+	}
+}