commit c13810192d243690dab4c0e890a1f50273a22ca1
Author: David Fifield <david at bamsoftware.com>
Date: Sun Jul 18 14:18:32 2021 -0600
Skeleton of ampCacheRendezvous.
Currently the same as httpRendezvous, but activated using the -ampcache
command-line option.
---
client/lib/rendezvous.go | 13 ++++++-
client/lib/rendezvous_ampcache.go | 78 +++++++++++++++++++++++++++++++++++++++
client/lib/snowflake.go | 7 ++--
client/snowflake.go | 3 +-
4 files changed, 95 insertions(+), 6 deletions(-)
diff --git a/client/lib/rendezvous.go b/client/lib/rendezvous.go
index 8568120..8af638f 100644
--- a/client/lib/rendezvous.go
+++ b/client/lib/rendezvous.go
@@ -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
}
diff --git a/client/lib/rendezvous_ampcache.go b/client/lib/rendezvous_ampcache.go
new file mode 100644
index 0000000..89745f4
--- /dev/null
+++ b/client/lib/rendezvous_ampcache.go
@@ -0,0 +1,78 @@
+package lib
+
+import (
+ "bytes"
+ "errors"
+ "log"
+ "net/http"
+ "net/url"
+)
+
+// 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 &CacheRendezvous{
+ 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)
+}
diff --git a/client/lib/snowflake.go b/client/lib/snowflake.go
index f643c0a..0fc7671 100644
--- a/client/lib/snowflake.go
+++ b/client/lib/snowflake.go
@@ -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(),
keepLocalAddresses)
if err != nil {
return nil, err
diff --git a/client/snowflake.go b/client/snowflake.go
index af9c2e4..ef06a2d 100644
--- a/client/snowflake.go
+++ b/client/snowflake.go
@@ -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)