commit 02562ba7504811659d801d06d9fdb1c3ecfa5d9b Author: Serene Han keroserene+git@gmail.com Date: Sun Jun 12 12:43:24 2016 -0700

copy-paste rendezvous works again, but with new interface allowing seamless recovery for the first time --- client/rendezvous.go | 112 +++++++++++++++++++++++++++++++++++++++++++++++++-- client/snowflake.go | 65 +++++------------------------- client/webrtc.go | 32 +-------------- 3 files changed, 122 insertions(+), 87 deletions(-)

diff --git a/client/rendezvous.go b/client/rendezvous.go index 3b25c89..0acee80 100644 --- a/client/rendezvous.go +++ b/client/rendezvous.go @@ -1,15 +1,26 @@ -// WebRTC Rendezvous requires the exchange of SessionDescriptions between -// peers. This file contains the domain-fronted HTTP signaling mechanism -// between the client and a desired Broker. +// WebRTC rendezvous requires the exchange of SessionDescriptions between +// peers in order to establish a PeerConnection. +// +// This file contains the two methods currently available to Snowflake: +// +// - Domain-fronted HTTP signaling. The Broker automatically exchange offers +// and answers between this client and some remote WebRTC proxy. +// (This is the recommended default, enabled via the flags in "torrc".) +// +// - Manual copy-paste signaling. User must create a signaling pipe. +// (The flags in torrc-manual allow this) package main

import ( + "bufio" "bytes" "errors" "io/ioutil" "log" "net/http" "net/url" + "os" + "syscall"

"github.com/keroserene/go-webrtc" ) @@ -100,3 +111,98 @@ func (bc *BrokerChannel) Negotiate(offer *webrtc.SessionDescription) ( return nil, errors.New(BrokerErrorUnexpected) } } + +// Implements the |Tongue| interface to catch snowflakes, using BrokerChannel. +type WebRTCDialer struct { + *BrokerChannel + webrtcConfig *webrtc.Configuration +} + +func NewWebRTCDialer( + broker *BrokerChannel, iceServers IceServerList) *WebRTCDialer { + config := webrtc.NewConfiguration(iceServers...) + return &WebRTCDialer{ + BrokerChannel: broker, + webrtcConfig: config, + } +} + +// Initialize a WebRTC Connection by signaling through the broker. +func (w WebRTCDialer) Catch() (*webRTCConn, error) { + if nil == w.BrokerChannel { + return nil, errors.New("Cannot Dial WebRTC without a BrokerChannel.") + } + // TODO: [#3] Fetch ICE server information from Broker. + // TODO: [#18] Consider TURN servers here too. + connection := NewWebRTCConnection(w.webrtcConfig, w.BrokerChannel) + err := connection.Connect() + return connection, err +} + +// CopyPasteDialer handles the interaction required to copy-paste the +// offers and answers. +// Implements |Tongue| interface to catch snowflakes manually. +// Supports recovery of connections. +type CopyPasteDialer struct { + webrtcConfig *webrtc.Configuration + signal *os.File + current *webRTCConn +} + +func NewCopyPasteDialer(iceServers IceServerList) *CopyPasteDialer { + log.Println("No HTTP signaling detected. Using manual copy-paste signaling.") + log.Println("Waiting for a "signal" pipe...") + // This FIFO receives signaling messages. + err := syscall.Mkfifo("signal", 0600) + if err != nil { + if syscall.EEXIST != err.(syscall.Errno) { + log.Fatal(err) + } + } + signalFile, err := os.OpenFile("signal", os.O_RDONLY, 0600) + if nil != err { + log.Fatal(err) + return nil + } + config := webrtc.NewConfiguration(iceServers...) + dialer := &CopyPasteDialer{ + webrtcConfig: config, + signal: signalFile, + } + go dialer.readSignals() + return dialer +} + +// Initialize a WebRTC connection via manual copy-paste. +func (d *CopyPasteDialer) Catch() (*webRTCConn, error) { + if nil == d.signal { + return nil, errors.New("Cannot copy-paste dial without signal pipe.") + } + connection := NewWebRTCConnection(d.webrtcConfig, nil) + // Must keep track of pending new connection until copy-paste completes. + d.current = connection + // Outputs SDP offer to log, expecting user to copy-paste to the remote Peer. + // Blocks until user pastes back the answer. + err := connection.Connect() + d.current = nil + return connection, err +} + +// Manual copy-paste signalling. +func (d *CopyPasteDialer) readSignals() { + defer d.signal.Close() + log.Printf("CopyPasteDialer: reading messages from signal pipe.") + s := bufio.NewScanner(d.signal) + for s.Scan() { + msg := s.Text() + sdp := webrtc.DeserializeSessionDescription(msg) + if sdp == nil { + log.Printf("CopyPasteDialer: ignoring invalid signal message %+q", msg) + continue + } + d.current.answerChannel <- sdp + } + if err := s.Err(); err != nil { + log.Printf("signal FIFO: %s", err) + } +} diff --git a/client/snowflake.go b/client/snowflake.go index 948b862..7c06b17 100644 --- a/client/snowflake.go +++ b/client/snowflake.go @@ -2,7 +2,6 @@ package main

import ( - "bufio" "errors" "flag" "io" @@ -110,45 +109,6 @@ func handler(socks SocksConnector, snowflakes SnowflakeCollector) error { return nil }

-func setupCopyPaste() { - log.Println("No HTTP signaling detected. Waiting for a "signal" pipe...") - // This FIFO receives signaling messages. - err := syscall.Mkfifo("signal", 0600) - if err != nil { - if syscall.EEXIST != err.(syscall.Errno) { - log.Fatal(err) - } - } - signalFile, err := os.OpenFile("signal", os.O_RDONLY, 0600) - if nil != err { - log.Fatal(err) - } - defer signalFile.Close() - go readSignalingMessages(signalFile) -} - -// Manual copy-paste signalling. -// TODO: Needs fix since multiplexing changes access to the remotes. -func readSignalingMessages(f *os.File) { - log.Printf("readSignalingMessages") - s := bufio.NewScanner(f) - for s.Scan() { - msg := s.Text() - log.Printf("readSignalingMessages loop %+q", msg) - sdp := webrtc.DeserializeSessionDescription(msg) - if sdp == nil { - log.Printf("ignoring invalid signal message %+q", msg) - continue - } - // webrtcRemotes[0].answerChannel <- sdp - } - log.Printf("close answerChannel") - // close(webrtcRemotes[0].answerChannel) - if err := s.Err(); err != nil { - log.Printf("signal FIFO: %s", err) - } -} - func main() { webrtc.SetLoggingVerbosity(1) logFile, err := os.OpenFile("snowflake.log", @@ -169,24 +129,24 @@ func main() { "capacity for number of multiplexed WebRTC peers") flag.Parse()

- // TODO: Maybe just get rid of copy-paste option entirely. - if "" == *brokerURL { - setupCopyPaste() - } - - // Prepare WebRTC SnowflakeCollector, Broker, then accumulate connections. + // Prepare to collect remote WebRTC peers. snowflakes := NewPeers(*max) - broker := NewBrokerChannel(*brokerURL, *frontDomain, CreateBrokerTransport()) - snowflakes.Tongue = NewWebRTCDialer(broker, iceServers) - - // Use a real logger for traffic. + if "" != *brokerURL { + // Use potentially domain-fronting broker to rendezvous. + broker := NewBrokerChannel(*brokerURL, *frontDomain, CreateBrokerTransport()) + snowflakes.Tongue = NewWebRTCDialer(broker, iceServers) + } else { + // Otherwise, use manual copy and pasting of SDP messages. + snowflakes.Tongue = NewCopyPasteDialer(iceServers) + } + // Use a real logger to periodically output how much traffic is happening. snowflakes.BytesLogger = &BytesSyncLogger{ inboundChan: make(chan int, 5), outboundChan: make(chan int, 5), inbound: 0, outbound: 0, inEvents: 0, outEvents: 0, } + go snowflakes.BytesLogger.Log()

go ConnectLoop(snowflakes) - go snowflakes.BytesLogger.Log()

// Begin goptlib client process. ptInfo, err := pt.ClientSetup(nil) @@ -197,7 +157,6 @@ func main() { pt.ProxyError("proxy is not supported") os.Exit(1) } - listeners := make([]net.Listener, 0) for _, methodName := range ptInfo.MethodNames { switch methodName { @@ -234,9 +193,7 @@ func main() { for _, ln := range listeners { ln.Close() } - snowflakes.End() - // wait for second signal or no more handlers sig = nil for sig == nil && numHandlers != 0 { diff --git a/client/webrtc.go b/client/webrtc.go index 7647cf6..2d26b7a 100644 --- a/client/webrtc.go +++ b/client/webrtc.go @@ -11,34 +11,6 @@ import ( "time" )

-// Implements the |Tongue| interface to catch snowflakes, using a BrokerChannel. -type WebRTCDialer struct { - *BrokerChannel - webrtcConfig *webrtc.Configuration -} - -func NewWebRTCDialer( - broker *BrokerChannel, iceServers IceServerList) *WebRTCDialer { - - config := webrtc.NewConfiguration(iceServers...) - return &WebRTCDialer{ - BrokerChannel: broker, - webrtcConfig: config, - } -} - -// Initialize a WebRTC Connection by signaling through the broker. -func (w WebRTCDialer) Catch() (*webRTCConn, error) { - if nil == w.BrokerChannel { - return nil, errors.New("Cannot Dial WebRTC without a BrokerChannel.") - } - // TODO: [#3] Fetch ICE server information from Broker. - // TODO: [#18] Consider TURN servers here too. - connection := NewWebRTCConnection(w.webrtcConfig, w.BrokerChannel) - err := connection.Connect() - return connection, err -} - // Remote WebRTC peer. Implements the |net.Conn| interface. type webRTCConn struct { config *webrtc.Configuration @@ -282,11 +254,11 @@ func (c *webRTCConn) sendOfferToBroker() { func (c *webRTCConn) exchangeSDP() error { select { case offer := <-c.offerChannel: - // Display for copy-paste, when no broker available. + // Display for copy-paste when no broker available. if nil == c.broker { log.Printf("Please Copy & Paste the following to the peer:") log.Printf("----------------") - log.Printf("\n" + offer.Serialize() + "\n") + log.Printf("\n\n" + offer.Serialize() + "\n\n") log.Printf("----------------") } case err := <-c.errorChannel: