Modified proxy-go to use pion/webrtc

The API is very similar, differences were mostly due to:
- closing peer connections and datachannels (no destroy/delete methods)
- different way to set datachannel/peer connection callbacks
- differences in whether functions take pointers or values
- no serialize/deserialize functions in the API

proxy-go/snowflake.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/rand"
 	"encoding/base64"
+	"encoding/json"
 	"flag"
 	"fmt"
 	"io"
@@ -19,7 +20,7 @@ import (
 	"time"
 
 	"git.torproject.org/pluggable-transports/snowflake.git/common/safelog"
-	"github.com/keroserene/go-webrtc"
+	"github.com/pion/webrtc"
 	"golang.org/x/net/websocket"
 )
 
@@ -43,7 +44,7 @@ const (
 
 var (
 	tokens chan bool
-	config *webrtc.Configuration
+	config webrtc.Configuration
 	client http.Client
 )
 
@@ -92,7 +93,7 @@ func (c *webRTCConn) Write(b []byte) (int, error) {
 
 func (c *webRTCConn) Close() (err error) {
 	c.once.Do(func() {
-		err = c.pc.Destroy()
+		err = c.pc.Close()
 	})
 	return
 }
@@ -103,7 +104,7 @@ func (c *webRTCConn) LocalAddr() net.Addr {
 
 func (c *webRTCConn) RemoteAddr() net.Addr {
 	//Parse Remote SDP offer and extract client IP
-	clientIP := remoteIPFromSDP(c.pc.RemoteDescription().Sdp)
+	clientIP := remoteIPFromSDP(c.pc.RemoteDescription().SDP)
 	if clientIP == nil {
 		return nil
 	}
@@ -178,7 +179,7 @@ func pollOffer(sid string) *webrtc.SessionDescription {
 				if err != nil {
 					log.Printf("error reading broker response: %s", err)
 				} else {
-					return webrtc.DeserializeSessionDescription(string(body))
+					return deserializeSessionDescription(string(body))
 				}
 			}
 		}
@@ -187,7 +188,7 @@ func pollOffer(sid string) *webrtc.SessionDescription {
 
 func sendAnswer(sid string, pc *webrtc.PeerConnection) error {
 	broker := brokerURL.ResolveReference(&url.URL{Path: "answer"})
-	body := bytes.NewBuffer([]byte(pc.LocalDescription().Serialize()))
+	body := bytes.NewBuffer([]byte(serializeSessionDescription(pc.LocalDescription())))
 	req, _ := http.NewRequest("POST", broker.String(), body)
 	req.Header.Set("X-Session-ID", sid)
 	resp, err := client.Do(req)
@@ -275,71 +276,63 @@ func datachannelHandler(conn *webRTCConn, remoteAddr net.Addr) {
 // candidates is complete and the answer is available in LocalDescription.
 // Installs an OnDataChannel callback that creates a webRTCConn and passes it to
 // datachannelHandler.
-func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc.Configuration, dataChan chan struct{}) (*webrtc.PeerConnection, error) {
+func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config webrtc.Configuration, dataChan chan struct{}) (*webrtc.PeerConnection, error) {
 	pc, err := webrtc.NewPeerConnection(config)
 	if err != nil {
 		return nil, fmt.Errorf("accept: NewPeerConnection: %s", err)
 	}
-	pc.OnNegotiationNeeded = func() {
+	pc.OnDataChannel(func(dc *webrtc.DataChannel) {
-		panic("OnNegotiationNeeded")
-	}
-	pc.OnDataChannel = func(dc *webrtc.DataChannel) {
 		log.Println("OnDataChannel")
 		close(dataChan)
 
 		pr, pw := io.Pipe()
 		conn := &webRTCConn{pc: pc, dc: dc, pr: pr}
 
-		dc.OnOpen = func() {
+		dc.OnOpen(func() {
 			log.Println("OnOpen channel")
-		}
+		})
-		dc.OnClose = func() {
+		dc.OnClose(func() {
 			conn.lock.Lock()
 			defer conn.lock.Unlock()
 			log.Println("OnClose channel")
 			conn.dc = nil
-			pc.DeleteDataChannel(dc)
+			dc.Close()
 			pw.Close()
-		}
+		})
-		dc.OnMessage = func(msg []byte) {
+		dc.OnMessage(func(msg webrtc.DataChannelMessage) {
-			log.Printf("OnMessage <--- %d bytes", len(msg))
+			log.Printf("OnMessage <--- %d bytes", len(msg.Data))
-			n, err := pw.Write(msg)
+			n, err := pw.Write(msg.Data)
 			if err != nil {
 				pw.CloseWithError(err)
 			}
-			if n != len(msg) {
+			if n != len(msg.Data) {
 				panic("short write")
 			}
-		}
+		})
 
 		go datachannelHandler(conn, conn.RemoteAddr())
-	}
+	})
 
-	err = pc.SetRemoteDescription(sdp)
+	err = pc.SetRemoteDescription(*sdp)
 	if err != nil {
-		pc.Destroy()
+		pc.Close()
 		return nil, fmt.Errorf("accept: SetRemoteDescription: %s", err)
 	}
 	log.Println("sdp offer successfully received.")
 
 	log.Println("Generating answer...")
-	answer, err := pc.CreateAnswer()
+	answer, err := pc.CreateAnswer(nil)
 	// blocks on ICE gathering. we need to add a timeout if needed
 	// not putting this in a separate go routine, because we need
 	// SetLocalDescription(answer) to be called before sendAnswer
 	if err != nil {
-		pc.Destroy()
+		pc.Close()
 		return nil, err
 	}
 
-	if answer == nil {
-		pc.Destroy()
-		return nil, fmt.Errorf("Failed gathering ICE candidates.")
-	}
-
 	err = pc.SetLocalDescription(answer)
 	if err != nil {
-		pc.Destroy()
+		pc.Close()
 		return nil, err
 	}
 
@@ -363,7 +356,7 @@ func runSession(sid string) {
 	err = sendAnswer(sid, pc)
 	if err != nil {
 		log.Printf("error sending answer to client through broker: %s", err)
-		pc.Destroy()
+		pc.Close()
 		retToken()
 		return
 	}
@@ -375,7 +368,7 @@ func runSession(sid string) {
 		log.Println("Connection successful.")
 	case <-time.After(dataChannelTimeout):
 		log.Println("Timed out waiting for client to open data channel.")
-		pc.Destroy()
+		pc.Close()
 		retToken()
 	}
 }
@@ -422,7 +415,13 @@ func main() {
 		log.Fatalf("invalid relay url: %s", err)
 	}
 
-	config = webrtc.NewConfiguration(webrtc.OptionIceServer(stunURL))
+	config = webrtc.Configuration{
+		ICEServers: []webrtc.ICEServer{
+			{
+				URLs: []string{stunURL},
+			},
+		},
+	}
 	tokens = make(chan bool, capacity)
 	for i := uint(0); i < capacity; i++ {
 		tokens <- true
@@ -434,3 +433,53 @@ func main() {
 		runSession(sessionID)
 	}
 }
+
+func deserializeSessionDescription(msg string) *webrtc.SessionDescription {
+	var parsed map[string]interface{}
+	err := json.Unmarshal([]byte(msg), &parsed)
+	if nil != err {
+		log.Println(err)
+		return nil
+	}
+	if _, ok := parsed["type"]; !ok {
+		log.Println("Cannot deserialize SessionDescription without type field.")
+		return nil
+	}
+	if _, ok := parsed["sdp"]; !ok {
+		log.Println("Cannot deserialize SessionDescription without sdp field.")
+		return nil
+	}
+
+	var stype webrtc.SDPType
+	switch parsed["type"].(string) {
+	default:
+		log.Println("Unknown SDP type")
+		return nil
+	case "offer":
+		stype = webrtc.SDPTypeOffer
+	case "pranswer":
+		stype = webrtc.SDPTypePranswer
+	case "answer":
+		stype = webrtc.SDPTypeAnswer
+	case "rollback":
+		stype = webrtc.SDPTypeRollback
+	}
+
+	if err != nil {
+		log.Println(err)
+		return nil
+	}
+	return &webrtc.SessionDescription{
+		Type: stype,
+		SDP:  parsed["sdp"].(string),
+	}
+}
+
+func serializeSessionDescription(desc *webrtc.SessionDescription) string {
+	bytes, err := json.Marshal(*desc)
+	if nil != err {
+		log.Println(err)
+		return ""
+	}
+	return string(bytes)
+}