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Move snowflake ConnectLoop inside SOCKS Handler

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Bug #21314: maintains a separate snowflake connect loop per SOCKS
connection. This way, if Tor decides to stop using Snowflake, Snowflake
will stop using the client's network.
This commit is contained in:
Cecylia Bocovich 2020-08-11 13:22:16 -04:00
parent d5ae7562ac
commit 1364d7d45b
3 changed files with 41 additions and 37 deletions
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6
client/lib/lib_test.go
View file

@ -157,11 +157,11 @@ func TestSnowflakeClient(t *testing.T) {
SkipConvey("Handler Grants correctly", func() {
socks := &FakeSocksConn{}
snowflakes := &FakePeers{}
broker := &BrokerChannel{Host: "test"}
d := NewWebRTCDialer(broker, nil)
So(socks.rejected, ShouldEqual, false)
snowflakes.toRelease = nil
Handler(socks, snowflakes)
Handler(socks, d)
So(socks.rejected, ShouldEqual, true)
})
})

34
client/lib/snowflake.go
View file

@ -142,7 +142,17 @@ var sessionManager = sessionManager_{}
// Given an accepted SOCKS connection, establish a WebRTC connection to the
// remote peer and exchange traffic.
func Handler(socks net.Conn, snowflakes SnowflakeCollector) error {
func Handler(socks net.Conn, tongue Tongue) error {
// Prepare to collect remote WebRTC peers.
snowflakes := NewPeers(1)
snowflakes.Tongue = tongue
// Use a real logger to periodically output how much traffic is happening.
snowflakes.BytesLogger = NewBytesSyncLogger()
log.Printf("---- Handler: begin collecting snowflakes ---")
go connectLoop(snowflakes)
// Return the global smux.Session.
sess, err := sessionManager.Get(snowflakes)
if err != nil {
@ -160,9 +170,31 @@ func Handler(socks net.Conn, snowflakes SnowflakeCollector) error {
log.Printf("---- Handler: begin stream %v ---", stream.ID())
copyLoop(socks, stream)
log.Printf("---- Handler: closed stream %v ---", stream.ID())
snowflakes.End()
log.Printf("---- Handler: end collecting snowflakes ---")
return nil
}
// Maintain |SnowflakeCapacity| number of available WebRTC connections, to
// transfer to the Tor SOCKS handler when needed.
func connectLoop(snowflakes SnowflakeCollector) {
for {
// Check if ending is necessary.
_, err := snowflakes.Collect()
if err != nil {
log.Printf("WebRTC: %v Retrying in %v...",
err, ReconnectTimeout)
}
select {
case <-time.After(ReconnectTimeout):
continue
case <-snowflakes.Melted():
log.Println("ConnectLoop: stopped.")
return
}
}
}
// Exchanges bytes between two ReadWriters.
// (In this case, between a SOCKS connection and smux stream.)
func copyLoop(socks, stream io.ReadWriter) {