[tor-commits] [snowflake/master] Update webrtc library to v3.0.0

cohosh at torproject.org cohosh at torproject.org
Tue Jan 12 15:39:18 UTC 2021


commit 83c01565ef90a13b0cab390fd59d7d36da76ec1e
Author: Cecylia Bocovich <cohosh at torproject.org>
Date:   Thu Dec 17 12:25:11 2020 -0500

    Update webrtc library to v3.0.0
    
    This update required two main changes to how we use the library. First,
    we had to make sure we created the datachannel on the offering peer side
    before creating the offer. Second, we had to make sure we wait for the
    gathering of all candidates to complete since trickle-ice is enabled by
    default. See the release notes for more details:
    https://github.com/pion/webrtc/wiki/Release-WebRTC@v3.0.0.
---
 client/lib/rendezvous.go |   3 +-
 client/lib/webrtc.go     | 100 +++++++++++++++---------------------
 client/snowflake.go      |   2 +-
 common/util/util.go      |   2 +-
 go.mod                   |   8 ++-
 go.sum                   | 130 ++++++++++++++++++++++++++++++-----------------
 probetest/probetest.go   |  10 ++--
 proxy/proxy-go_test.go   |   2 +-
 proxy/snowflake.go       |  47 +++++++++++------
 9 files changed, 171 insertions(+), 133 deletions(-)

diff --git a/client/lib/rendezvous.go b/client/lib/rendezvous.go
index 10853a5..32da081 100644
--- a/client/lib/rendezvous.go
+++ b/client/lib/rendezvous.go
@@ -21,7 +21,7 @@ import (
 
 	"git.torproject.org/pluggable-transports/snowflake.git/common/nat"
 	"git.torproject.org/pluggable-transports/snowflake.git/common/util"
-	"github.com/pion/webrtc/v2"
+	"github.com/pion/webrtc/v3"
 )
 
 const (
@@ -134,6 +134,7 @@ func (bc *BrokerChannel) Negotiate(offer *webrtc.SessionDescription) (
 		if nil != err {
 			return nil, err
 		}
+		log.Printf("Received answer: %s", string(body))
 		return util.DeserializeSessionDescription(string(body))
 	case http.StatusServiceUnavailable:
 		return nil, errors.New(BrokerError503)
diff --git a/client/lib/webrtc.go b/client/lib/webrtc.go
index 3a23ffc..af7ba6d 100644
--- a/client/lib/webrtc.go
+++ b/client/lib/webrtc.go
@@ -9,7 +9,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/pion/webrtc/v2"
+	"github.com/pion/webrtc/v3"
 )
 
 // Remote WebRTC peer.
@@ -25,6 +25,7 @@ type WebRTCPeer struct {
 	writePipe   *io.PipeWriter
 	lastReceive time.Time
 
+	open   chan struct{} // Channel to notify when datachannel opens
 	closed bool
 
 	once sync.Once // Synchronization for PeerConnection destruction
@@ -107,11 +108,7 @@ func (c *WebRTCPeer) connect(config *webrtc.Configuration, broker *BrokerChannel
 	log.Println(c.id, " connecting...")
 	// TODO: When go-webrtc is more stable, it's possible that a new
 	// PeerConnection won't need to be re-prepared each time.
-	var err error
-	c.pc, err = preparePeerConnection(config)
-	if err != nil {
-		return err
-	}
+	c.preparePeerConnection(config)
 	answer, err := broker.Negotiate(c.pc.LocalDescription())
 	if err != nil {
 		return err
@@ -122,73 +119,42 @@ func (c *WebRTCPeer) connect(config *webrtc.Configuration, broker *BrokerChannel
 		log.Println("WebRTC: Unable to SetRemoteDescription:", err)
 		return err
 	}
-	c.transport, err = c.establishDataChannel()
-	if err != nil {
-		log.Printf("WebRTC: establishing data channel: %v", err)
-		// nolint: golint
-		return errors.New("WebRTC: Could not establish DataChannel")
+
+	// Wait for the datachannel to open or time out
+	select {
+	case <-c.open:
+	case <-time.After(DataChannelTimeout):
+		c.transport.Close()
+		return errors.New("timeout waiting for DataChannel.OnOpen")
 	}
+
 	go c.checkForStaleness()
 	return nil
 }
 
 // preparePeerConnection creates a new WebRTC PeerConnection and returns it
 // after ICE candidate gathering is complete..
-func preparePeerConnection(config *webrtc.Configuration) (*webrtc.PeerConnection, error) {
-	pc, err := webrtc.NewPeerConnection(*config)
+func (c *WebRTCPeer) preparePeerConnection(config *webrtc.Configuration) error {
+	var err error
+	c.pc, err = webrtc.NewPeerConnection(*config)
 	if err != nil {
 		log.Printf("NewPeerConnection ERROR: %s", err)
-		return nil, err
-	}
-	// Prepare PeerConnection callbacks.
-	offerChannel := make(chan struct{})
-	// Allow candidates to accumulate until ICEGatheringStateComplete.
-	pc.OnICECandidate(func(candidate *webrtc.ICECandidate) {
-		if candidate == nil {
-			log.Printf("WebRTC: Done gathering candidates")
-			close(offerChannel)
-		} else {
-			log.Printf("WebRTC: Got ICE candidate: %s", candidate.String())
-		}
-	})
-
-	offer, err := pc.CreateOffer(nil)
-	// TODO: Potentially timeout and retry if ICE isn't working.
-	if err != nil {
-		log.Println("Failed to prepare offer", err)
-		pc.Close()
-		return nil, err
-	}
-	log.Println("WebRTC: Created offer")
-	err = pc.SetLocalDescription(offer)
-	if err != nil {
-		log.Println("Failed to prepare offer", err)
-		pc.Close()
-		return nil, err
+		return err
 	}
-	log.Println("WebRTC: Set local description")
-
-	<-offerChannel // Wait for ICE candidate gathering to complete.
-	log.Println("WebRTC: PeerConnection created.")
-	return pc, nil
-}
-
-// Create a WebRTC DataChannel locally. Blocks until the data channel is open,
-// or a timeout or error occurs.
-func (c *WebRTCPeer) establishDataChannel() (*webrtc.DataChannel, error) {
 	ordered := true
 	dataChannelOptions := &webrtc.DataChannelInit{
 		Ordered: &ordered,
 	}
+	// We must create the data channel before creating an offer
+	// https://github.com/pion/webrtc/wiki/Release-WebRTC@v3.0.0
 	dc, err := c.pc.CreateDataChannel(c.id, dataChannelOptions)
 	if err != nil {
 		log.Printf("CreateDataChannel ERROR: %s", err)
-		return nil, err
+		return err
 	}
-	openChannel := make(chan struct{})
 	dc.OnOpen(func() {
 		log.Println("WebRTC: DataChannel.OnOpen")
-		close(openChannel)
+		close(c.open)
 	})
 	dc.OnClose(func() {
 		log.Println("WebRTC: DataChannel.OnClose")
@@ -209,15 +175,31 @@ func (c *WebRTCPeer) establishDataChannel() (*webrtc.DataChannel, error) {
 		}
 		c.lastReceive = time.Now()
 	})
+	c.transport = dc
+	c.open = make(chan struct{})
 	log.Println("WebRTC: DataChannel created.")
 
-	select {
-	case <-openChannel:
-		return dc, nil
-	case <-time.After(DataChannelTimeout):
-		dc.Close()
-		return nil, errors.New("timeout waiting for DataChannel.OnOpen")
+	// Allow candidates to accumulate until ICEGatheringStateComplete.
+	done := webrtc.GatheringCompletePromise(c.pc)
+	offer, err := c.pc.CreateOffer(nil)
+	// TODO: Potentially timeout and retry if ICE isn't working.
+	if err != nil {
+		log.Println("Failed to prepare offer", err)
+		c.pc.Close()
+		return err
+	}
+	log.Println("WebRTC: Created offer")
+	err = c.pc.SetLocalDescription(offer)
+	if err != nil {
+		log.Println("Failed to prepare offer", err)
+		c.pc.Close()
+		return err
 	}
+	log.Println("WebRTC: Set local description")
+
+	<-done // Wait for ICE candidate gathering to complete.
+	log.Println("WebRTC: PeerConnection created.")
+	return nil
 }
 
 // Close all channels and transports
diff --git a/client/snowflake.go b/client/snowflake.go
index e293e73..d79de97 100644
--- a/client/snowflake.go
+++ b/client/snowflake.go
@@ -20,7 +20,7 @@ import (
 	sf "git.torproject.org/pluggable-transports/snowflake.git/client/lib"
 	"git.torproject.org/pluggable-transports/snowflake.git/common/nat"
 	"git.torproject.org/pluggable-transports/snowflake.git/common/safelog"
-	"github.com/pion/webrtc/v2"
+	"github.com/pion/webrtc/v3"
 )
 
 const (
diff --git a/common/util/util.go b/common/util/util.go
index b317e0b..3d2acc3 100644
--- a/common/util/util.go
+++ b/common/util/util.go
@@ -6,7 +6,7 @@ import (
 	"net"
 
 	"github.com/pion/sdp/v2"
-	"github.com/pion/webrtc/v2"
+	"github.com/pion/webrtc/v3"
 )
 
 func SerializeSessionDescription(desc *webrtc.SessionDescription) (string, error) {
diff --git a/go.mod b/go.mod
index 2ba1b2d..2931be7 100644
--- a/go.mod
+++ b/go.mod
@@ -4,15 +4,13 @@ go 1.13
 
 require (
 	git.torproject.org/pluggable-transports/goptlib.git v1.1.0
-	github.com/golang/protobuf v1.3.1 // indirect
 	github.com/gorilla/websocket v1.4.1
 	github.com/pion/sdp/v2 v2.3.4
 	github.com/pion/stun v0.3.5
-	github.com/pion/webrtc/v2 v2.2.2
+	github.com/pion/webrtc/v3 v3.0.0
 	github.com/smartystreets/goconvey v1.6.4
 	github.com/xtaci/kcp-go/v5 v5.5.12
 	github.com/xtaci/smux v1.5.12
-	golang.org/x/crypto v0.0.0-20200128174031-69ecbb4d6d5d
-	golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa
-	golang.org/x/text v0.3.2 // indirect
+	golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897
+	golang.org/x/net v0.0.0-20201201195509-5d6afe98e0b7
 )
diff --git a/go.sum b/go.sum
index 9ccfb30..6214f5c 100644
--- a/go.sum
+++ b/go.sum
@@ -1,18 +1,24 @@
 git.torproject.org/pluggable-transports/goptlib.git v1.1.0 h1:LMQAA8pAho+QtYrrVNimJQiINNEwcwuuD99vezD/PAo=
 git.torproject.org/pluggable-transports/goptlib.git v1.1.0/go.mod h1:YT4XMSkuEXbtqlydr9+OxqFAyspUv0Gr9qhM3B++o/Q=
-github.com/cheekybits/genny v1.0.0 h1:uGGa4nei+j20rOSeDeP5Of12XVm7TGUd4dJA9RDitfE=
-github.com/cheekybits/genny v1.0.0/go.mod h1:+tQajlRqAUrPI7DOSpB0XAqZYtQakVtB7wXkRAgjxjQ=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
-github.com/golang/mock v1.2.0 h1:28o5sBqPkBsMGnC6b4MvE2TzSr5/AT4c/1fLqVGIwlk=
-github.com/golang/mock v1.2.0/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
+github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
 github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
-github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
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+github.com/google/uuid v1.1.2 h1:EVhdT+1Kseyi1/pUmXKaFxYsDNy9RQYkMWRH68J/W7Y=
+github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
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 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/gorilla/websocket v1.4.1 h1:q7AeDBpnBk8AogcD4DSag/Ukw/KV+YhzLj2bP5HvKCM=
@@ -30,49 +36,56 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
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-github.com/lucas-clemente/quic-go v0.7.1-0.20190401152353-907071221cf9 h1:tbuodUh2vuhOVZAdW3NEUvosFHUMJwUNl7jk/VSEiwc=
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@@ -84,10 +97,11 @@ github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1
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@@ -100,34 +114,55 @@ github.com/xtaci/lossyconn v0.0.0-20190602105132-8df528c0c9ae h1:J0GxkO96kL4WF+A
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 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
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@@ -135,6 +170,9 @@ gopkg.in/fsnotify.v1 v1.4.7 h1:xOHLXZwVvI9hhs+cLKq5+I5onOuwQLhQwiu63xxlHs4=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 h1:uRGJdciOHaEIrze2W8Q3AKkepLTh2hOroT7a+7czfdQ=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
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 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
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+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/probetest/probetest.go b/probetest/probetest.go
index d952123..f9bc96b 100644
--- a/probetest/probetest.go
+++ b/probetest/probetest.go
@@ -24,7 +24,7 @@ import (
 	"git.torproject.org/pluggable-transports/snowflake.git/common/safelog"
 	"git.torproject.org/pluggable-transports/snowflake.git/common/util"
 
-	"github.com/pion/webrtc/v2"
+	"github.com/pion/webrtc/v3"
 	"golang.org/x/crypto/acme/autocert"
 )
 
@@ -58,7 +58,10 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription,
 			dc.Close()
 		})
 	})
-
+	// As of v3.0.0, pion-webrtc uses trickle ICE by default.
+	// We have to wait for candidate gathering to complete
+	// before we send the offer
+	done := webrtc.GatheringCompletePromise(pc)
 	err = pc.SetRemoteDescription(*sdp)
 	if err != nil {
 		if inerr := pc.Close(); inerr != nil {
@@ -82,7 +85,8 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription,
 		}
 		return nil, err
 	}
-
+	// Wait for ICE candidate gathering to complete
+	<-done
 	return pc, nil
 }
 
diff --git a/proxy/proxy-go_test.go b/proxy/proxy-go_test.go
index e2fb82e..e935ad9 100644
--- a/proxy/proxy-go_test.go
+++ b/proxy/proxy-go_test.go
@@ -14,7 +14,7 @@ import (
 
 	"git.torproject.org/pluggable-transports/snowflake.git/common/messages"
 	"git.torproject.org/pluggable-transports/snowflake.git/common/util"
-	"github.com/pion/webrtc/v2"
+	"github.com/pion/webrtc/v3"
 	. "github.com/smartystreets/goconvey/convey"
 )
 
diff --git a/proxy/snowflake.go b/proxy/snowflake.go
index f0fa2c0..78a053d 100644
--- a/proxy/snowflake.go
+++ b/proxy/snowflake.go
@@ -24,7 +24,7 @@ import (
 	"git.torproject.org/pluggable-transports/snowflake.git/common/websocketconn"
 	"github.com/gorilla/websocket"
 	"github.com/pion/sdp/v2"
-	"github.com/pion/webrtc/v2"
+	"github.com/pion/webrtc/v3"
 )
 
 const defaultBrokerURL = "https://snowflake-broker.bamsoftware.com/"
@@ -394,7 +394,10 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription,
 
 		go handler(conn, conn.RemoteAddr())
 	})
-
+	// As of v3.0.0, pion-webrtc uses trickle ICE by default.
+	// We have to wait for candidate gathering to complete
+	// before we send the offer
+	done := webrtc.GatheringCompletePromise(pc)
 	err = pc.SetRemoteDescription(*sdp)
 	if err != nil {
 		if inerr := pc.Close(); inerr != nil {
@@ -423,7 +426,8 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription,
 		}
 		return nil, err
 	}
-
+	// Wait for ICE candidate gathering to complete
+	<-done
 	return pc, nil
 }
 
@@ -437,6 +441,22 @@ func makeNewPeerConnection(config webrtc.Configuration,
 		return nil, fmt.Errorf("accept: NewPeerConnection: %s", err)
 	}
 
+	// Must create a data channel before creating an offer
+	// https://github.com/pion/webrtc/wiki/Release-WebRTC@v3.0.0
+	dc, err := pc.CreateDataChannel("test", &webrtc.DataChannelInit{})
+	if err != nil {
+		log.Printf("CreateDataChannel ERROR: %s", err)
+		return nil, err
+	}
+	dc.OnOpen(func() {
+		log.Println("WebRTC: DataChannel.OnOpen")
+		close(dataChan)
+	})
+	dc.OnClose(func() {
+		log.Println("WebRTC: DataChannel.OnClose")
+		dc.Close()
+	})
+
 	offer, err := pc.CreateOffer(nil)
 	// TODO: Potentially timeout and retry if ICE isn't working.
 	if err != nil {
@@ -445,6 +465,11 @@ func makeNewPeerConnection(config webrtc.Configuration,
 		return nil, err
 	}
 	log.Println("WebRTC: Created offer")
+
+	// As of v3.0.0, pion-webrtc uses trickle ICE by default.
+	// We have to wait for candidate gathering to complete
+	// before we send the offer
+	done := webrtc.GatheringCompletePromise(pc)
 	err = pc.SetLocalDescription(offer)
 	if err != nil {
 		log.Println("Failed to prepare offer", err)
@@ -453,19 +478,8 @@ func makeNewPeerConnection(config webrtc.Configuration,
 	}
 	log.Println("WebRTC: Set local description")
 
-	dc, err := pc.CreateDataChannel("test", &webrtc.DataChannelInit{})
-	if err != nil {
-		log.Printf("CreateDataChannel ERROR: %s", err)
-		return nil, err
-	}
-	dc.OnOpen(func() {
-		log.Println("WebRTC: DataChannel.OnOpen")
-		close(dataChan)
-	})
-	dc.OnClose(func() {
-		log.Println("WebRTC: DataChannel.OnClose")
-		dc.Close()
-	})
+	// Wait for ICE candidate gathering to complete
+	<-done
 	return pc, nil
 }
 
@@ -606,6 +620,7 @@ func checkNATType(config webrtc.Configuration, probeURL string) {
 
 	offer := pc.LocalDescription()
 	sdp, err := util.SerializeSessionDescription(offer)
+	log.Printf("Offer: %s", sdp)
 	if err != nil {
 		log.Printf("Error encoding probe message: %s", err.Error())
 		return



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