commit 046dab865f18eb12a473b1a1c1d7aa15cf5883c7
Author: Cecylia Bocovich <coh...@torproject.org>
Date: Mon Jun 22 14:04:29 2020 -0400
Have broker pass client NAT type to proxy
This will allow browser-based proxies that are unable to determine their
NAT type to conservatively label themselves as restricted NATs if they
fail to work with clients that have restricted NATs.
---
broker/broker.go | 31 ++++++++++++++++++++-----------
broker/snowflake-broker_test.go | 26 +++++++++++++-------------
broker/snowflake-heap.go | 2 +-
common/messages/proxy.go | 24 ++++++++++++++++--------
common/messages/proxy_test.go | 16 +++++++++-------
proxy/proxy-go_test.go | 2 +-
proxy/snowflake.go | 2 +-
7 files changed, 61 insertions(+), 42 deletions(-)
diff --git a/broker/broker.go b/broker/broker.go
index 9297980..99f6c69 100644
--- a/broker/broker.go
+++ b/broker/broker.go
@@ -111,17 +111,17 @@ type ProxyPoll struct {
id string
proxyType string
natType string
- offerChannel chan []byte
+ offerChannel chan *ClientOffer
}
// Registers a Snowflake and waits for some Client to send an offer,
// as part of the polling logic of the proxy handler.
-func (ctx *BrokerContext) RequestOffer(id string, proxyType string, natType
string) []byte {
+func (ctx *BrokerContext) RequestOffer(id string, proxyType string, natType
string) *ClientOffer {
request := new(ProxyPoll)
request.id = id
request.proxyType = proxyType
request.natType = natType
- request.offerChannel = make(chan []byte)
+ request.offerChannel = make(chan *ClientOffer)
ctx.proxyPolls <- request
// Block until an offer is available, or timeout which sends a nil
offer.
offer := <-request.offerChannel
@@ -165,7 +165,7 @@ func (ctx *BrokerContext) AddSnowflake(id string, proxyType
string, natType stri
snowflake.id = id
snowflake.clients = 0
snowflake.proxyType = proxyType
- snowflake.offerChannel = make(chan []byte)
+ snowflake.offerChannel = make(chan *ClientOffer)
snowflake.answerChannel = make(chan []byte)
ctx.snowflakeLock.Lock()
if natType == NATRestricted {
@@ -213,7 +213,7 @@ func proxyPolls(ctx *BrokerContext, w http.ResponseWriter,
r *http.Request) {
ctx.metrics.proxyIdleCount++
ctx.metrics.lock.Unlock()
- b, err = messages.EncodePollResponse("", false)
+ b, err = messages.EncodePollResponse("", false, "")
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
return
@@ -222,7 +222,7 @@ func proxyPolls(ctx *BrokerContext, w http.ResponseWriter,
r *http.Request) {
w.Write(b)
return
}
- b, err = messages.EncodePollResponse(string(offer), true)
+ b, err = messages.EncodePollResponse(string(offer.sdp), true,
offer.natType)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
return
@@ -232,28 +232,37 @@ func proxyPolls(ctx *BrokerContext, w
http.ResponseWriter, r *http.Request) {
}
}
+// Client offer contains an SDP and the NAT type of the client
+type ClientOffer struct {
+ natType string
+ sdp []byte
+}
+
/*
Expects a WebRTC SDP offer in the Request to give to an assigned
snowflake proxy, which responds with the SDP answer to be sent in
the HTTP response back to the client.
*/
func clientOffers(ctx *BrokerContext, w http.ResponseWriter, r *http.Request) {
+ var err error
+
startTime := time.Now()
- offer, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, readLimit))
+ offer := &ClientOffer{}
+ offer.sdp, err = ioutil.ReadAll(http.MaxBytesReader(w, r.Body,
readLimit))
if nil != err {
log.Println("Invalid data.")
w.WriteHeader(http.StatusBadRequest)
return
}
- natType := r.Header.Get("Snowflake-NAT-Type")
- if natType == "" {
- natType = NATUnknown
+ offer.natType = r.Header.Get("Snowflake-NAT-Type")
+ if offer.natType == "" {
+ offer.natType = NATUnknown
}
// Only hand out known restricted snowflakes to unrestricted clients
var snowflakeHeap *SnowflakeHeap
- if natType == NATUnrestricted {
+ if offer.natType == NATUnrestricted {
snowflakeHeap = ctx.restrictedSnowflakes
} else {
snowflakeHeap = ctx.snowflakes
diff --git a/broker/snowflake-broker_test.go b/broker/snowflake-broker_test.go
index 91383a1..d03dca7 100644
--- a/broker/snowflake-broker_test.go
+++ b/broker/snowflake-broker_test.go
@@ -37,7 +37,7 @@ func TestBroker(t *testing.T) {
Convey("Broker goroutine matches clients with proxies", func() {
p := new(ProxyPoll)
p.id = "test"
- p.offerChannel = make(chan []byte)
+ p.offerChannel = make(chan *ClientOffer)
go func(ctx *BrokerContext) {
ctx.proxyPolls <- p
close(ctx.proxyPolls)
@@ -45,23 +45,23 @@ func TestBroker(t *testing.T) {
ctx.Broker()
So(ctx.snowflakes.Len(), ShouldEqual, 1)
snowflake := heap.Pop(ctx.snowflakes).(*Snowflake)
- snowflake.offerChannel <- []byte("test offer")
+ snowflake.offerChannel <- &ClientOffer{sdp:
[]byte("test offer")}
offer := <-p.offerChannel
So(ctx.idToSnowflake["test"], ShouldNotBeNil)
- So(offer, ShouldResemble, []byte("test offer"))
+ So(offer.sdp, ShouldResemble, []byte("test offer"))
So(ctx.snowflakes.Len(), ShouldEqual, 0)
})
Convey("Request an offer from the Snowflake Heap", func() {
- done := make(chan []byte)
+ done := make(chan *ClientOffer)
go func() {
offer := ctx.RequestOffer("test", "",
NATUnknown)
done <- offer
}()
request := <-ctx.proxyPolls
- request.offerChannel <- []byte("test offer")
+ request.offerChannel <- &ClientOffer{sdp: []byte("test
offer")}
offer := <-done
- So(offer, ShouldResemble, []byte("test offer"))
+ So(offer.sdp, ShouldResemble, []byte("test offer"))
})
Convey("Responds to client offers...", func() {
@@ -85,7 +85,7 @@ func TestBroker(t *testing.T) {
done <- true
}()
offer := <-snowflake.offerChannel
- So(offer, ShouldResemble, []byte("test"))
+ So(offer.sdp, ShouldResemble, []byte("test"))
snowflake.answerChannel <- []byte("fake answer")
<-done
So(w.Body.String(), ShouldEqual, "fake answer")
@@ -104,7 +104,7 @@ func TestBroker(t *testing.T) {
done <- true
}()
offer := <-snowflake.offerChannel
- So(offer, ShouldResemble, []byte("test"))
+ So(offer.sdp, ShouldResemble, []byte("test"))
<-done
So(w.Code, ShouldEqual,
http.StatusGatewayTimeout)
})
@@ -125,10 +125,10 @@ func TestBroker(t *testing.T) {
// Pass a fake client offer to this proxy
p := <-ctx.proxyPolls
So(p.id, ShouldEqual, "ymbcCMto7KHNGYlp")
- p.offerChannel <- []byte("fake offer")
+ p.offerChannel <- &ClientOffer{sdp:
[]byte("fake offer")}
<-done
So(w.Code, ShouldEqual, http.StatusOK)
- So(w.Body.String(), ShouldEqual,
`{"Status":"client match","Offer":"fake offer"}`)
+ So(w.Body.String(), ShouldEqual,
`{"Status":"client match","Offer":"fake offer","NAT":""}`)
})
Convey("return empty 200 OK when no client offer is
available.", func() {
@@ -141,7 +141,7 @@ func TestBroker(t *testing.T) {
// nil means timeout
p.offerChannel <- nil
<-done
- So(w.Body.String(), ShouldEqual, `{"Status":"no
match","Offer":""}`)
+ So(w.Body.String(), ShouldEqual, `{"Status":"no
match","Offer":"","NAT":""}`)
So(w.Code, ShouldEqual, http.StatusOK)
})
})
@@ -279,7 +279,7 @@ func TestBroker(t *testing.T) {
<-polled
So(wP.Code, ShouldEqual, http.StatusOK)
- So(wP.Body.String(), ShouldResemble, `{"Status":"client
match","Offer":"fake offer"}`)
+ So(wP.Body.String(), ShouldResemble, `{"Status":"client
match","Offer":"fake offer","NAT":"unknown"}`)
So(ctx.idToSnowflake["ymbcCMto7KHNGYlp"],
ShouldNotBeNil)
// Follow up with the answer request afterwards
wA := httptest.NewRecorder()
@@ -543,7 +543,7 @@ func TestMetrics(t *testing.T) {
done <- true
}()
offer := <-snowflake.offerChannel
- So(offer, ShouldResemble, []byte("test"))
+ So(offer.sdp, ShouldResemble, []byte("test"))
snowflake.answerChannel <- []byte("fake answer")
<-done
diff --git a/broker/snowflake-heap.go b/broker/snowflake-heap.go
index 19a64b2..12fe557 100644
--- a/broker/snowflake-heap.go
+++ b/broker/snowflake-heap.go
@@ -11,7 +11,7 @@ over the offer and answer channels.
type Snowflake struct {
id string
proxyType string
- offerChannel chan []byte
+ offerChannel chan *ClientOffer
answerChannel chan []byte
clients int
index int
diff --git a/common/messages/proxy.go b/common/messages/proxy.go
index 923189b..2d9e58d 100644
--- a/common/messages/proxy.go
+++ b/common/messages/proxy.go
@@ -29,7 +29,8 @@ HTTP 200 OK
{
type: offer,
sdp: [WebRTC SDP]
- }
+ },
+ NAT: ["unknown"|"restricted"|"unrestricted"]
}
2) If a client is not matched:
@@ -120,13 +121,15 @@ func DecodePollRequest(data []byte) (string, string,
string, error) {
type ProxyPollResponse struct {
Status string
Offer string
+ NAT string
}
-func EncodePollResponse(offer string, success bool) ([]byte, error) {
+func EncodePollResponse(offer string, success bool, natType string) ([]byte,
error) {
if success {
return json.Marshal(ProxyPollResponse{
Status: "client match",
Offer: offer,
+ NAT: natType,
})
}
@@ -135,28 +138,33 @@ func EncodePollResponse(offer string, success bool)
([]byte, error) {
})
}
-// Decodes a poll response from the broker and returns an offer
+// Decodes a poll response from the broker and returns an offer and the
client's NAT type
// If there is a client match, the returned offer string will be non-empty
-func DecodePollResponse(data []byte) (string, error) {
+func DecodePollResponse(data []byte) (string, string, error) {
var message ProxyPollResponse
err := json.Unmarshal(data, &message)
if err != nil {
- return "", err
+ return "", "", err
}
if message.Status == "" {
- return "", fmt.Errorf("received invalid data")
+ return "", "", fmt.Errorf("received invalid data")
}
if message.Status == "client match" {
if message.Offer == "" {
- return "", fmt.Errorf("no supplied offer")
+ return "", "", fmt.Errorf("no supplied offer")
}
} else {
message.Offer = ""
}
- return message.Offer, nil
+ natType := message.NAT
+ if natType == "" {
+ natType = "unknown"
+ }
+
+ return message.Offer, natType, nil
}
type ProxyAnswerRequest struct {
diff --git a/common/messages/proxy_test.go b/common/messages/proxy_test.go
index 3aa67fb..f4191e1 100644
--- a/common/messages/proxy_test.go
+++ b/common/messages/proxy_test.go
@@ -109,7 +109,7 @@ func TestDecodeProxyPollResponse(t *testing.T) {
}{
{
"fake offer",
- `{"Status":"client match","Offer":"fake
offer"}`,
+ `{"Status":"client match","Offer":"fake
offer","NAT":"unknown"}`,
nil,
},
{
@@ -128,9 +128,9 @@ func TestDecodeProxyPollResponse(t *testing.T) {
fmt.Errorf(""),
},
} {
- offer, err := DecodePollResponse([]byte(test.data))
- So(offer, ShouldResemble, test.offer)
+ offer, _, err := DecodePollResponse([]byte(test.data))
So(err, ShouldHaveSameTypeAs, test.err)
+ So(offer, ShouldResemble, test.offer)
}
})
@@ -138,16 +138,18 @@ func TestDecodeProxyPollResponse(t *testing.T) {
func TestEncodeProxyPollResponse(t *testing.T) {
Convey("Context", t, func() {
- b, err := EncodePollResponse("fake offer", true)
+ b, err := EncodePollResponse("fake offer", true, "restricted")
So(err, ShouldEqual, nil)
- offer, err := DecodePollResponse(b)
+ offer, natType, err := DecodePollResponse(b)
So(offer, ShouldEqual, "fake offer")
+ So(natType, ShouldEqual, "restricted")
So(err, ShouldEqual, nil)
- b, err = EncodePollResponse("", false)
+ b, err = EncodePollResponse("", false, "unknown")
So(err, ShouldEqual, nil)
- offer, err = DecodePollResponse(b)
+ offer, natType, err = DecodePollResponse(b)
So(offer, ShouldEqual, "")
+ So(natType, ShouldEqual, "unknown")
So(err, ShouldEqual, nil)
})
}
diff --git a/proxy/proxy-go_test.go b/proxy/proxy-go_test.go
index 03d7307..168ca25 100644
--- a/proxy/proxy-go_test.go
+++ b/proxy/proxy-go_test.go
@@ -249,7 +249,7 @@ func TestBrokerInteractions(t *testing.T) {
Convey("polls broker correctly", func() {
var err error
- b, err := messages.EncodePollResponse(sampleOffer, true)
+ b, err := messages.EncodePollResponse(sampleOffer,
true, "unknown")
So(err, ShouldEqual, nil)
broker.transport = &MockTransport{
http.StatusOK,
diff --git a/proxy/snowflake.go b/proxy/snowflake.go
index ac67748..a1886c2 100644
--- a/proxy/snowflake.go
+++ b/proxy/snowflake.go
@@ -201,7 +201,7 @@ func (b *Broker) pollOffer(sid string)
*webrtc.SessionDescription {
log.Printf("error reading broker
response: %s", err)
} else {
- offer, err :=
messages.DecodePollResponse(body)
+ offer, _, err :=
messages.DecodePollResponse(body)
if err != nil {
log.Printf("error reading
broker response: %s", err.Error())
log.Printf("body: %s", body)
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