mirror of
https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake.git
synced 2025-10-13 20:11:19 -04:00
able to break out of ConnectLoop, try separate webrtcConfigs as well
This commit is contained in:
parent
4ca0a3aa0a
commit
a71c98c0ae
6 changed files with 69 additions and 46 deletions
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@ -67,6 +67,7 @@ type FakePeers struct{ toRelease *webRTCConn }
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func (f FakePeers) Collect() error { return nil }
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func (f FakePeers) Pop() Snowflake { return nil }
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func (f FakePeers) Melted() <-chan struct{} { return nil }
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func TestSnowflakeClient(t *testing.T) {
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@ -144,6 +145,7 @@ func TestSnowflakeClient(t *testing.T) {
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}
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So(p.Count(), ShouldEqual, cnt)
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p.End()
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<-p.Melted()
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So(p.Count(), ShouldEqual, 0)
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})
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@ -168,7 +170,6 @@ func TestSnowflakeClient(t *testing.T) {
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Convey("Can construct a WebRTCConn", func() {
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s := NewWebRTCConnection(nil, nil)
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So(s, ShouldNotBeNil)
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So(s.index, ShouldEqual, 0)
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So(s.offerChannel, ShouldNotBeNil)
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So(s.answerChannel, ShouldNotBeNil)
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s.Close()
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@ -176,13 +177,13 @@ func TestSnowflakeClient(t *testing.T) {
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Convey("Write buffers when datachannel is nil", func() {
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c.Write([]byte("test"))
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c.snowflake = nil
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c.transport = nil
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So(c.buffer.Bytes(), ShouldResemble, []byte("test"))
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})
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Convey("Write sends to datachannel when not nil", func() {
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mock := new(MockDataChannel)
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c.snowflake = mock
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c.transport = mock
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mock.done = make(chan bool, 1)
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c.Write([]byte("test"))
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<-mock.done
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@ -38,6 +38,9 @@ type SnowflakeCollector interface {
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// Remove and return the most available Snowflake from the collection.
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Pop() Snowflake
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// Signal when the collector has stopped collecting.
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Melted() <-chan struct{}
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}
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// Interface to adapt to goptlib's SocksConn struct.
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@ -25,6 +25,8 @@ type Peers struct {
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snowflakeChan chan Snowflake
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activePeers *list.List
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capacity int
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melt chan struct{}
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}
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// Construct a fresh container of remote peers.
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@ -33,17 +35,19 @@ func NewPeers(max int) *Peers {
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// Use buffered go channel to pass snowflakes onwards to the SOCKS handler.
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p.snowflakeChan = make(chan Snowflake, max)
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p.activePeers = list.New()
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p.melt = make(chan struct{}, 1)
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return p
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}
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// As part of |SnowflakeCollector| interface.
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func (p *Peers) Collect() error {
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cnt := p.Count()
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s := fmt.Sprintf("Currently at [%d/%d]", cnt, p.capacity)
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if cnt >= p.capacity {
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s := fmt.Sprintf("At capacity [%d/%d]", cnt, p.capacity)
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return errors.New(s)
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}
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log.Println("WebRTC: Collecting a new Snowflake.", s)
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// Engage the Snowflake Catching interface, which must be available.
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if nil == p.Tongue {
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return errors.New("Missing Tongue to catch Snowflakes with.")
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@ -60,7 +64,6 @@ func (p *Peers) Collect() error {
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// As part of |SnowflakeCollector| interface.
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func (p *Peers) Pop() Snowflake {
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// Blocks until an available snowflake appears.
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snowflake, ok := <-p.snowflakeChan
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if !ok {
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@ -71,6 +74,11 @@ func (p *Peers) Pop() Snowflake {
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return snowflake
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}
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// As part of |SnowflakeCollector| interface.
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func (p *Peers) Melted() <-chan struct{} {
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return p.melt
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}
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// Returns total available Snowflakes (including the active one)
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// The count only reduces when connections themselves close, rather than when
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// they are popped.
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@ -93,9 +101,16 @@ func (p *Peers) purgeClosedPeers() {
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// Close all Peers contained here.
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func (p *Peers) End() {
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log.Printf("WebRTC: Ending all peer connections.")
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for e := p.activePeers.Front(); e != nil; e = e.Next() {
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close(p.snowflakeChan)
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p.melt <- struct{}{}
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cnt := p.Count()
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for e := p.activePeers.Front(); e != nil; {
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log.Println(e, e.Value)
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next := e.Next()
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conn := e.Value.(*webRTCConn)
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conn.Close()
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p.activePeers.Remove(e)
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e = next
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}
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log.Println("WebRTC: melted all", cnt, "snowflakes.")
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}
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@ -115,15 +115,17 @@ func (bc *BrokerChannel) Negotiate(offer *webrtc.SessionDescription) (
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// Implements the |Tongue| interface to catch snowflakes, using BrokerChannel.
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type WebRTCDialer struct {
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*BrokerChannel
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webrtcConfig *webrtc.Configuration
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// webrtcConfig *webrtc.Configuration
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iceServers IceServerList
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}
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func NewWebRTCDialer(
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broker *BrokerChannel, iceServers IceServerList) *WebRTCDialer {
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config := webrtc.NewConfiguration(iceServers...)
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return &WebRTCDialer{
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BrokerChannel: broker,
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webrtcConfig: config,
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iceServers: iceServers,
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// webrtcConfig: config,
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}
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}
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@ -134,7 +136,8 @@ func (w WebRTCDialer) Catch() (Snowflake, error) {
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}
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// TODO: [#3] Fetch ICE server information from Broker.
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// TODO: [#18] Consider TURN servers here too.
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connection := NewWebRTCConnection(w.webrtcConfig, w.BrokerChannel)
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config := webrtc.NewConfiguration(w.iceServers...)
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connection := NewWebRTCConnection(config, w.BrokerChannel)
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err := connection.Connect()
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return connection, err
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}
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@ -30,17 +30,19 @@ var handlerChan = make(chan int)
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// transfer to the Tor SOCKS handler when needed.
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func ConnectLoop(snowflakes SnowflakeCollector) {
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for {
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// Check if ending is necessary.
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err := snowflakes.Collect()
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if nil != err {
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log.Println("WebRTC:", err,
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" Retrying in", ReconnectTimeout, "seconds...")
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// Failed collections get a timeout.
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<-time.After(time.Second * ReconnectTimeout)
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continue
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}
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// Successful collection gets rate limited to once per second.
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log.Println("WebRTC: Connected to new Snowflake.")
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<-time.After(time.Second)
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select {
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case <-time.After(time.Second * ReconnectTimeout):
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continue
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case <-snowflakes.Melted():
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log.Println("ConnectLoop: stopped.")
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return
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}
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}
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}
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@ -50,7 +52,7 @@ func socksAcceptLoop(ln *pt.SocksListener, snowflakes SnowflakeCollector) error
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log.Println("Started SOCKS listener.")
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for {
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conn, err := ln.AcceptSocks()
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log.Println("SOCKS accepted ", conn.Req)
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log.Println("SOCKS accepted: ", conn.Req)
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if err != nil {
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if e, ok := err.(net.Error); ok && e.Temporary() {
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continue
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@ -72,6 +74,7 @@ func handler(socks SocksConnector, snowflakes SnowflakeCollector) error {
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handlerChan <- -1
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}()
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// Obtain an available WebRTC remote. May block.
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log.Println("handler: awaiting Snowflake...")
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snowflake := snowflakes.Pop()
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if nil == snowflake {
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socks.Reject()
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@ -85,6 +88,7 @@ func handler(socks SocksConnector, snowflakes SnowflakeCollector) error {
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}
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// Begin exchanging data.
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// BUG(serene): There's a leak here when multiplexed.
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go copyLoop(socks, snowflake)
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// When WebRTC resets, close the SOCKS connection, which induces new handler.
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@ -15,19 +15,17 @@ import (
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type webRTCConn struct {
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config *webrtc.Configuration
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pc *webrtc.PeerConnection
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snowflake SnowflakeDataChannel // Holds the WebRTC DataChannel.
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transport SnowflakeDataChannel // Holds the WebRTC DataChannel.
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broker *BrokerChannel
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offerChannel chan *webrtc.SessionDescription
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answerChannel chan *webrtc.SessionDescription
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errorChannel chan error
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endChannel chan struct{}
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recvPipe *io.PipeReader
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writePipe *io.PipeWriter
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buffer bytes.Buffer
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reset chan struct{}
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index int
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closed bool
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BytesLogger
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@ -43,11 +41,11 @@ func (c *webRTCConn) Read(b []byte) (int, error) {
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// As part of |io.ReadWriter|
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func (c *webRTCConn) Write(b []byte) (int, error) {
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c.BytesLogger.AddOutbound(len(b))
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if nil == c.snowflake {
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if nil == c.transport {
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log.Printf("Buffered %d bytes --> WebRTC", len(b))
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c.buffer.Write(b)
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} else {
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c.snowflake.Send(b)
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c.transport.Send(b)
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}
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return len(b), nil
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}
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@ -57,15 +55,6 @@ func (c *webRTCConn) Close() error {
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var err error = nil
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log.Printf("WebRTC: Closing")
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c.cleanup()
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if nil != c.offerChannel {
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close(c.offerChannel)
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}
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if nil != c.answerChannel {
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close(c.answerChannel)
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}
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if nil != c.errorChannel {
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close(c.errorChannel)
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}
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// Mark for deletion.
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c.closed = true
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return err
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@ -106,7 +95,6 @@ func NewWebRTCConnection(config *webrtc.Configuration,
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// As part of |Connector| interface.
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func (c *webRTCConn) Connect() error {
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log.Printf("Establishing WebRTC connection #%d...", c.index)
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// TODO: When go-webrtc is more stable, it's possible that a new
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// PeerConnection won't need to be re-prepared each time.
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err := c.preparePeerConnection()
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@ -174,7 +162,7 @@ func (c *webRTCConn) preparePeerConnection() error {
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// Create a WebRTC DataChannel locally.
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func (c *webRTCConn) establishDataChannel() error {
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if c.snowflake != nil {
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if c.transport != nil {
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panic("Unexpected datachannel already exists!")
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}
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dc, err := c.pc.CreateDataChannel("snowflake", webrtc.Init{})
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@ -187,9 +175,8 @@ func (c *webRTCConn) establishDataChannel() error {
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}
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dc.OnOpen = func() {
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log.Println("WebRTC: DataChannel.OnOpen")
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if nil != c.snowflake {
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log.Println("PeerConnection snowflake already exists.")
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panic("PeerConnection snowflake already exists.")
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if nil != c.transport {
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panic("WebRTC: transport already exists.")
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}
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// Flush buffered outgoing SOCKS data if necessary.
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if c.buffer.Len() > 0 {
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@ -198,11 +185,11 @@ func (c *webRTCConn) establishDataChannel() error {
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c.buffer.Reset()
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}
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// Then enable the datachannel.
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c.snowflake = dc
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c.transport = dc
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}
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dc.OnClose = func() {
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// Future writes will go to the buffer until a new DataChannel is available.
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if nil == c.snowflake {
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if nil == c.transport {
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// Closed locally, as part of a reset.
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log.Println("WebRTC: DataChannel.OnClose [locally]")
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return
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@ -210,7 +197,7 @@ func (c *webRTCConn) establishDataChannel() error {
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// Closed remotely, need to reset everything.
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// Disable the DataChannel as a write destination.
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log.Println("WebRTC: DataChannel.OnClose [remotely]")
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c.snowflake = nil
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c.transport = nil
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c.Reset()
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}
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dc.OnMessage = func(msg []byte) {
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@ -284,13 +271,23 @@ func (c *webRTCConn) exchangeSDP() error {
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return nil
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}
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// Close all channels and transports
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func (c *webRTCConn) cleanup() {
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if nil != c.snowflake {
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if nil != c.offerChannel {
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close(c.offerChannel)
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}
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if nil != c.answerChannel {
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close(c.answerChannel)
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}
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if nil != c.errorChannel {
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close(c.errorChannel)
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}
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if nil != c.transport {
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log.Printf("WebRTC: closing DataChannel")
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dataChannel := c.snowflake
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// Setting snowflake to nil *before* Close indicates to OnClose that it
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dataChannel := c.transport
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// Setting dc to nil *before* Close indicates to OnClose that it
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// was locally triggered.
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c.snowflake = nil
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c.transport = nil
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dataChannel.Close()
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}
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if nil != c.pc {
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