Commit 06ca0e86 authored by David Fifield's avatar David Fifield
Browse files

Skeleton of ampCacheRendezvous.

Currently the same as httpRendezvous, but activated using the -ampcache
command-line option.
parent cd56247a
......@@ -59,13 +59,22 @@ func CreateBrokerTransport() http.RoundTripper {
// Construct a new BrokerChannel, where:
// |broker| is the full URL of the facilitating program which assigns proxies
// to clients, and |front| is the option fronting domain.
func NewBrokerChannel(broker string, front string, transport http.RoundTripper, keepLocalAddresses bool) (*BrokerChannel, error) {
func NewBrokerChannel(broker, ampCache, front string, transport http.RoundTripper, keepLocalAddresses bool) (*BrokerChannel, error) {
log.Println("Rendezvous using Broker at:", broker)
if ampCache != "" {
log.Println("Through AMP cache at:", ampCache)
if front != "" {
log.Println("Domain fronting using:", front)
rendezvous, err := newHTTPRendezvous(broker, front, transport)
var rendezvous rendezvousMethod
var err error
if ampCache != "" {
rendezvous, err = newAMPCacheRendezvous(broker, ampCache, front, transport)
} else {
rendezvous, err = newHTTPRendezvous(broker, front, transport)
if err != nil {
return nil, err
package lib
import (
// ampCacheRendezvous is a rendezvousMethod that communicates with the
// .../amp/client route of the broker, optionally over an AMP cache proxy, and
// with optional domain fronting.
type ampCacheRendezvous struct {
brokerURL *url.URL
cacheURL *url.URL // Optional AMP cache URL.
front string // Optional front domain to replace url.Host in requests.
transport http.RoundTripper // Used to make all requests.
// newAMPCacheRendezvous creates a new ampCacheRendezvous that contacts the
// broker at the given URL, optionally proxying through an AMP cache, and with
// an optional front domain. transport is the http.RoundTripper used to make all
// requests.
func newAMPCacheRendezvous(broker, cache, front string, transport http.RoundTripper) (*ampCacheRendezvous, error) {
brokerURL, err := url.Parse(broker)
if err != nil {
return nil, err
var cacheURL *url.URL
if cache != "" {
var err error
cacheURL, err = url.Parse(cache)
if err != nil {
return nil, err
return &ampCacheRendezvous{
brokerURL: brokerURL,
cacheURL: cacheURL,
front: front,
transport: transport,
}, nil
func (r *ampCacheRendezvous) Exchange(encPollReq []byte) ([]byte, error) {
log.Println("Negotiating via AMP cache rendezvous...")
log.Println("Broker URL:", r.brokerURL)
log.Println("AMP cache URL:", r.cacheURL)
log.Println("Front domain:", r.front)
// Suffix the path with the broker's client registration handler.
reqURL := r.brokerURL.ResolveReference(&url.URL{Path: "client"})
req, err := http.NewRequest("POST", reqURL.String(), bytes.NewReader(encPollReq))
if err != nil {
return nil, err
if r.front != "" {
// Do domain fronting. Replace the domain in the URL's with the
// front, and store the original domain the HTTP Host header.
req.Host = req.URL.Host
req.URL.Host = r.front
resp, err := r.transport.RoundTrip(req)
if err != nil {
return nil, err
defer resp.Body.Close()
log.Printf("AMP cache rendezvous response: %s", resp.Status)
if resp.StatusCode != http.StatusOK {
return nil, errors.New(BrokerErrorUnexpected)
return limitedRead(resp.Body, readLimit)
......@@ -39,7 +39,8 @@ type Transport struct {
// iceAddresses are the STUN/TURN urls needed for WebRTC negotiation
// keepLocalAddresses is a flag to enable sending local network addresses (for testing purposes)
// max is the maximum number of snowflakes the client should gather for each SOCKS connection
func NewSnowflakeClient(brokerURL, frontDomain string, iceAddresses []string, keepLocalAddresses bool, max int) (*Transport, error) {
func NewSnowflakeClient(brokerURL, ampCacheURL, frontDomain string,
iceAddresses []string, keepLocalAddresses bool, max int) (*Transport, error) {
log.Println("\n\n\n --- Starting Snowflake Client ---")
......@@ -57,9 +58,9 @@ func NewSnowflakeClient(brokerURL, frontDomain string, iceAddresses []string, ke
log.Printf("url: %v", strings.Join(server.URLs, " "))
// Use potentially domain-fronting broker to rendezvous.
// Rendezvous with broker using the given parameters.
broker, err := NewBrokerChannel(
brokerURL, frontDomain, CreateBrokerTransport(),
brokerURL, ampCacheURL, frontDomain, CreateBrokerTransport(),
if err != nil {
return nil, err
......@@ -94,6 +94,7 @@ func main() {
iceServersCommas := flag.String("ice", "", "comma-separated list of ICE servers")
brokerURL := flag.String("url", "", "URL of signaling broker")
frontDomain := flag.String("front", "", "front domain")
ampCacheURL := flag.String("ampcache", "", "URL of AMP cache to use as a proxy for signaling")
logFilename := flag.String("log", "", "name of log file")
logToStateDir := flag.Bool("log-to-state-dir", false, "resolve the log file relative to tor's pt state dir")
keepLocalAddresses := flag.Bool("keep-local-addresses", false, "keep local LAN address ICE candidates")
......@@ -140,7 +141,7 @@ func main() {
iceAddresses := strings.Split(strings.TrimSpace(*iceServersCommas), ",")
transport, err := sf.NewSnowflakeClient(*brokerURL, *frontDomain, iceAddresses,
transport, err := sf.NewSnowflakeClient(*brokerURL, *ampCacheURL, *frontDomain, iceAddresses,
*keepLocalAddresses || *oldKeepLocalAddresses, *max)
if err != nil {
log.Fatal("Failed to start snowflake transport: ", err)
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