commit 7a1857c42fdbaf78207d9e25ea814fe1d531036c Author: meskio meskio@torproject.org Date: Fri Jun 25 13:47:47 2021 +0200

Make the proxy to report the number of clients to the broker

So the assignment of proxies is based on the load. The number of clients is ronded down to 8. Existing proxies that doesn't report the number of clients will be distributed equaly to new proxies until they get 8 clients, that is okish as the existing proxies do have a maximum capacity of 10.

Fixes #40048 --- broker/broker.go | 14 +++++---- broker/snowflake-broker_test.go | 18 ++++++------ common/messages/messages_test.go | 26 +++++++++++++++-- common/messages/proxy.go | 28 +++++++++++------- doc/broker-spec.txt | 4 ++- proxy/proxy-go_test.go | 17 ++--------- proxy/snowflake.go | 63 +++++++++++++++++++--------------------- proxy/tokens.go | 44 ++++++++++++++++++++++++++++ proxy/tokens_test.go | 28 ++++++++++++++++++ 9 files changed, 165 insertions(+), 77 deletions(-)

diff --git a/broker/broker.go b/broker/broker.go index 906c210..fc4727d 100644 --- a/broker/broker.go +++ b/broker/broker.go @@ -124,16 +124,18 @@ type ProxyPoll struct { id string proxyType string natType string + clients int 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) *ClientOffer { +func (ctx *BrokerContext) RequestOffer(id string, proxyType string, natType string, clients int) *ClientOffer { request := new(ProxyPoll) request.id = id request.proxyType = proxyType request.natType = natType + request.clients = clients request.offerChannel = make(chan *ClientOffer) ctx.proxyPolls <- request // Block until an offer is available, or timeout which sends a nil offer. @@ -146,7 +148,7 @@ func (ctx *BrokerContext) RequestOffer(id string, proxyType string, natType stri // client offer or nil on timeout / none are available. func (ctx *BrokerContext) Broker() { for request := range ctx.proxyPolls { - snowflake := ctx.AddSnowflake(request.id, request.proxyType, request.natType) + snowflake := ctx.AddSnowflake(request.id, request.proxyType, request.natType, request.clients) // Wait for a client to avail an offer to the snowflake. go func(request *ProxyPoll) { select { @@ -174,10 +176,10 @@ func (ctx *BrokerContext) Broker() { // Create and add a Snowflake to the heap. // Required to keep track of proxies between providing them // with an offer and awaiting their second POST with an answer. -func (ctx *BrokerContext) AddSnowflake(id string, proxyType string, natType string) *Snowflake { +func (ctx *BrokerContext) AddSnowflake(id string, proxyType string, natType string, clients int) *Snowflake { snowflake := new(Snowflake) snowflake.id = id - snowflake.clients = 0 + snowflake.clients = clients snowflake.proxyType = proxyType snowflake.natType = natType snowflake.offerChannel = make(chan *ClientOffer) @@ -205,7 +207,7 @@ func proxyPolls(ctx *BrokerContext, w http.ResponseWriter, r *http.Request) { return }

- sid, proxyType, natType, err := messages.DecodePollRequest(body) + sid, proxyType, natType, clients, err := messages.DecodePollRequest(body) if err != nil { w.WriteHeader(http.StatusBadRequest) return @@ -222,7 +224,7 @@ func proxyPolls(ctx *BrokerContext, w http.ResponseWriter, r *http.Request) { }

// Wait for a client to avail an offer to the snowflake, or timeout if nil. - offer := ctx.RequestOffer(sid, proxyType, natType) + offer := ctx.RequestOffer(sid, proxyType, natType, clients) var b []byte if nil == offer { ctx.metrics.lock.Lock() diff --git a/broker/snowflake-broker_test.go b/broker/snowflake-broker_test.go index 646fb02..825bc6f 100644 --- a/broker/snowflake-broker_test.go +++ b/broker/snowflake-broker_test.go @@ -32,7 +32,7 @@ func TestBroker(t *testing.T) { Convey("Adds Snowflake", func() { So(ctx.snowflakes.Len(), ShouldEqual, 0) So(len(ctx.idToSnowflake), ShouldEqual, 0) - ctx.AddSnowflake("foo", "", NATUnrestricted) + ctx.AddSnowflake("foo", "", NATUnrestricted, 0) So(ctx.snowflakes.Len(), ShouldEqual, 1) So(len(ctx.idToSnowflake), ShouldEqual, 1) }) @@ -59,7 +59,7 @@ func TestBroker(t *testing.T) { Convey("Request an offer from the Snowflake Heap", func() { done := make(chan *ClientOffer) go func() { - offer := ctx.RequestOffer("test", "", NATUnrestricted) + offer := ctx.RequestOffer("test", "", NATUnrestricted, 0) done <- offer }() request := <-ctx.proxyPolls @@ -84,7 +84,7 @@ func TestBroker(t *testing.T) { Convey("with a proxy answer if available.", func() { done := make(chan bool) // Prepare a fake proxy to respond with. - snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted) + snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted, 0) go func() { clientOffers(ctx, w, r) done <- true @@ -102,7 +102,7 @@ func TestBroker(t *testing.T) { return } done := make(chan bool) - snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted) + snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted, 0) go func() { clientOffers(ctx, w, r) // Takes a few seconds here... @@ -132,7 +132,7 @@ func TestBroker(t *testing.T) { Convey("with a proxy answer if available.", func() { done := make(chan bool) // Prepare a fake proxy to respond with. - snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted) + snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted, 0) go func() { clientOffers(ctx, w, r) done <- true @@ -150,7 +150,7 @@ func TestBroker(t *testing.T) { return } done := make(chan bool) - snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted) + snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted, 0) go func() { clientOffers(ctx, w, r) // Takes a few seconds here... @@ -201,7 +201,7 @@ func TestBroker(t *testing.T) { })

Convey("Responds to proxy answers...", func() { - s := ctx.AddSnowflake("test", "", NATUnrestricted) + s := ctx.AddSnowflake("test", "", NATUnrestricted, 0) w := httptest.NewRecorder() data := bytes.NewReader([]byte(`{"Version":"1.0","Sid":"test","Answer":"test"}`))

@@ -314,7 +314,7 @@ func TestBroker(t *testing.T) { // Manually do the Broker goroutine action here for full control. p := <-ctx.proxyPolls So(p.id, ShouldEqual, "ymbcCMto7KHNGYlp") - s := ctx.AddSnowflake(p.id, "", NATUnrestricted) + s := ctx.AddSnowflake(p.id, "", NATUnrestricted, 0) go func() { offer := <-s.offerChannel p.offerChannel <- offer @@ -593,7 +593,7 @@ func TestMetrics(t *testing.T) { So(err, ShouldBeNil)

// Prepare a fake proxy to respond with. - snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted) + snowflake := ctx.AddSnowflake("fake", "", NATUnrestricted, 0) go func() { clientOffers(ctx, w, r) done <- true diff --git a/common/messages/messages_test.go b/common/messages/messages_test.go index 3962d3b..abb978d 100644 --- a/common/messages/messages_test.go +++ b/common/messages/messages_test.go @@ -15,6 +15,7 @@ func TestDecodeProxyPollRequest(t *testing.T) { sid string proxyType string natType string + clients int data string err error }{ @@ -23,6 +24,7 @@ func TestDecodeProxyPollRequest(t *testing.T) { "ymbcCMto7KHNGYlp", "", "unknown", + 0, `{"Sid":"ymbcCMto7KHNGYlp","Version":"1.0"}`, nil, }, @@ -31,6 +33,7 @@ func TestDecodeProxyPollRequest(t *testing.T) { "ymbcCMto7KHNGYlp", "standalone", "unknown", + 0, `{"Sid":"ymbcCMto7KHNGYlp","Version":"1.1","Type":"standalone"}`, nil, }, @@ -39,14 +42,25 @@ func TestDecodeProxyPollRequest(t *testing.T) { "ymbcCMto7KHNGYlp", "standalone", "restricted", + 0, `{"Sid":"ymbcCMto7KHNGYlp","Version":"1.2","Type":"standalone", "NAT":"restricted"}`, nil, }, + { + //Version 1.2 proxy message with clients + "ymbcCMto7KHNGYlp", + "standalone", + "restricted", + 24, + `{"Sid":"ymbcCMto7KHNGYlp","Version":"1.2","Type":"standalone", "NAT":"restricted","Clients":24}`, + nil, + }, { //Version 0.X proxy message: "", "", "", + 0, "", &json.SyntaxError{}, }, @@ -54,6 +68,7 @@ func TestDecodeProxyPollRequest(t *testing.T) { "", "", "", + 0, `{"Sid":"ymbcCMto7KHNGYlp"}`, fmt.Errorf(""), }, @@ -61,6 +76,7 @@ func TestDecodeProxyPollRequest(t *testing.T) { "", "", "", + 0, "{}", fmt.Errorf(""), }, @@ -68,6 +84,7 @@ func TestDecodeProxyPollRequest(t *testing.T) { "", "", "", + 0, `{"Version":"1.0"}`, fmt.Errorf(""), }, @@ -75,14 +92,16 @@ func TestDecodeProxyPollRequest(t *testing.T) { "", "", "", + 0, `{"Version":"2.0"}`, fmt.Errorf(""), }, } { - sid, proxyType, natType, err := DecodePollRequest([]byte(test.data)) + sid, proxyType, natType, clients, err := DecodePollRequest([]byte(test.data)) So(sid, ShouldResemble, test.sid) So(proxyType, ShouldResemble, test.proxyType) So(natType, ShouldResemble, test.natType) + So(clients, ShouldEqual, test.clients) So(err, ShouldHaveSameTypeAs, test.err) }

@@ -91,12 +110,13 @@ func TestDecodeProxyPollRequest(t *testing.T) {

func TestEncodeProxyPollRequests(t *testing.T) { Convey("Context", t, func() { - b, err := EncodePollRequest("ymbcCMto7KHNGYlp", "standalone", "unknown") + b, err := EncodePollRequest("ymbcCMto7KHNGYlp", "standalone", "unknown", 16) So(err, ShouldEqual, nil) - sid, proxyType, natType, err := DecodePollRequest(b) + sid, proxyType, natType, clients, err := DecodePollRequest(b) So(sid, ShouldEqual, "ymbcCMto7KHNGYlp") So(proxyType, ShouldEqual, "standalone") So(natType, ShouldEqual, "unknown") + So(clients, ShouldEqual, 16) So(err, ShouldEqual, nil) }) } diff --git a/common/messages/proxy.go b/common/messages/proxy.go index 2d9e58d..366e833 100644 --- a/common/messages/proxy.go +++ b/common/messages/proxy.go @@ -17,8 +17,9 @@ const version = "1.2" { Sid: [generated session id of proxy], Version: 1.2, - Type: ["badge"|"webext"|"standalone"] - NAT: ["unknown"|"restricted"|"unrestricted"] + Type: ["badge"|"webext"|"standalone"], + NAT: ["unknown"|"restricted"|"unrestricted"], + Clients: [number of current clients, rounded down to multiples of 8] }

== ProxyPollResponse == @@ -79,43 +80,48 @@ type ProxyPollRequest struct { Version string Type string NAT string + Clients int }

-func EncodePollRequest(sid string, proxyType string, natType string) ([]byte, error) { +func EncodePollRequest(sid string, proxyType string, natType string, clients int) ([]byte, error) { return json.Marshal(ProxyPollRequest{ Sid: sid, Version: version, Type: proxyType, NAT: natType, + Clients: clients, }) }

// Decodes a poll message from a snowflake proxy and returns the -// sid and proxy type of the proxy on success and an error if it failed -func DecodePollRequest(data []byte) (string, string, string, error) { +// sid, proxy type, nat type and clients of the proxy on success +// and an error if it failed +func DecodePollRequest(data []byte) (sid string, proxyType string, natType string, clients int, err error) { var message ProxyPollRequest

- err := json.Unmarshal(data, &message) + err = json.Unmarshal(data, &message) if err != nil { - return "", "", "", err + return }

majorVersion := strings.Split(message.Version, ".")[0] if majorVersion != "1" { - return "", "", "", fmt.Errorf("using unknown version") + err = fmt.Errorf("using unknown version") + return }

// Version 1.x requires an Sid if message.Sid == "" { - return "", "", "", fmt.Errorf("no supplied session id") + err = fmt.Errorf("no supplied session id") + return }

- natType := message.NAT + natType = message.NAT if natType == "" { natType = "unknown" }

- return message.Sid, message.Type, natType, nil + return message.Sid, message.Type, natType, message.Clients, nil }

type ProxyPollResponse struct { diff --git a/doc/broker-spec.txt b/doc/broker-spec.txt index 9e4b8ae..f2cd231 100644 --- a/doc/broker-spec.txt +++ b/doc/broker-spec.txt @@ -141,7 +141,9 @@ POST /proxy HTTP { Sid: [generated session id of proxy], Version: 1.1, - Type: ["badge"|"webext"|"standalone"|"mobile"] + Type: ["badge"|"webext"|"standalone"|"mobile"], + NAT: ["unknown"|"restricted"|"unrestricted"], + Clients: [number of current clients, rounded down to multiples of 8] } ```

diff --git a/proxy/proxy-go_test.go b/proxy/proxy-go_test.go index e935ad9..183b1b4 100644 --- a/proxy/proxy-go_test.go +++ b/proxy/proxy-go_test.go @@ -7,7 +7,6 @@ import ( "io/ioutil" "net" "net/http" - "net/url" "strconv" "strings" "testing" @@ -337,8 +336,9 @@ func TestBrokerInteractions(t *testing.T) { const sampleAnswer = `{"type":"answer","sdp":` + sampleSDP + `}`

Convey("Proxy connections to broker", t, func() { - broker := new(SignalingServer) - broker.url, _ = url.Parse("localhost") + broker, err := newSignalingServer("localhost", false) + So(err, ShouldEqual, nil) + tokens = newTokens(0)

//Mock peerConnection config = webrtc.Configuration{ @@ -469,17 +469,6 @@ func TestUtilityFuncs(t *testing.T) { So(err, ShouldEqual, io.ErrClosedPipe) }) }) - Convey("Tokens", t, func() { - tokens = make(chan bool, 2) - for i := uint(0); i < 2; i++ { - tokens <- true - } - So(len(tokens), ShouldEqual, 2) - getToken() - So(len(tokens), ShouldEqual, 1) - retToken() - So(len(tokens), ShouldEqual, 2) - }) Convey("SessionID Generation", t, func() { sid1 := genSessionID() sid2 := genSessionID() diff --git a/proxy/snowflake.go b/proxy/snowflake.go index 86ae0b2..f7eacf8 100644 --- a/proxy/snowflake.go +++ b/proxy/snowflake.go @@ -55,7 +55,7 @@ const ( )

var ( - tokens chan bool + tokens *tokens_t config webrtc.Configuration client http.Client ) @@ -171,14 +171,6 @@ func (c *webRTCConn) SetWriteDeadline(t time.Time) error { return fmt.Errorf("SetWriteDeadline not implemented") }

-func getToken() { - <-tokens -} - -func retToken() { - tokens <- true -} - func genSessionID() string { buf := make([]byte, sessionIDLength) _, err := rand.Read(buf) @@ -204,6 +196,21 @@ type SignalingServer struct { keepLocalAddresses bool }

+func newSignalingServer(rawURL string, keepLocalAddresses bool) (*SignalingServer, error) { + var err error + s := new(SignalingServer) + s.keepLocalAddresses = keepLocalAddresses + s.url, err = url.Parse(rawURL) + if err != nil { + return nil, fmt.Errorf("invalid broker url: %s", err) + } + + s.transport = http.DefaultTransport.(*http.Transport) + s.transport.(*http.Transport).ResponseHeaderTimeout = 30 * time.Second + + return s, nil +} + func (s *SignalingServer) Post(path string, payload io.Reader) ([]byte, error) {

req, err := http.NewRequest("POST", path, payload) @@ -238,7 +245,8 @@ func (s *SignalingServer) pollOffer(sid string) *webrtc.SessionDescription { timeOfNextPoll = now }

- body, err := messages.EncodePollRequest(sid, "standalone", currentNATType) + numClients := int((tokens.count() / 8) * 8) // Round down to 8 + body, err := messages.EncodePollRequest(sid, "standalone", currentNATType, numClients) if err != nil { log.Printf("Error encoding poll message: %s", err.Error()) return nil @@ -323,7 +331,7 @@ func CopyLoop(c1 io.ReadWriteCloser, c2 io.ReadWriteCloser) { // RemoteAddr). https://bugs.torproject.org/18628#comment:8 func datachannelHandler(conn *webRTCConn, remoteAddr net.Addr) { defer conn.Close() - defer retToken() + defer tokens.ret()

u, err := url.Parse(relayURL) if err != nil { @@ -494,14 +502,14 @@ func runSession(sid string) { offer := broker.pollOffer(sid) if offer == nil { log.Printf("bad offer from broker") - retToken() + tokens.ret() return } dataChan := make(chan struct{}) pc, err := makePeerConnectionFromOffer(offer, config, dataChan, datachannelHandler) if err != nil { log.Printf("error making WebRTC connection: %s", err) - retToken() + tokens.ret() return } err = broker.sendAnswer(sid, pc) @@ -510,7 +518,7 @@ func runSession(sid string) { if inerr := pc.Close(); inerr != nil { log.Printf("error calling pc.Close: %v", inerr) } - retToken() + tokens.ret() return } // Set a timeout on peerconnection. If the connection state has not @@ -524,7 +532,7 @@ func runSession(sid string) { if err := pc.Close(); err != nil { log.Printf("error calling pc.Close: %v", err) } - retToken() + tokens.ret() } }

@@ -536,7 +544,7 @@ func main() { var unsafeLogging bool var keepLocalAddresses bool

- flag.UintVar(&capacity, "capacity", 10, "maximum concurrent clients") + flag.UintVar(&capacity, "capacity", 0, "maximum concurrent clients") flag.StringVar(&rawBrokerURL, "broker", defaultBrokerURL, "broker URL") flag.StringVar(&relayURL, "relay", defaultRelayURL, "websocket relay URL") flag.StringVar(&stunURL, "stun", defaultSTUNURL, "stun URL") @@ -565,12 +573,11 @@ func main() { log.Println("starting")

var err error - broker = new(SignalingServer) - broker.keepLocalAddresses = keepLocalAddresses - broker.url, err = url.Parse(rawBrokerURL) + broker, err = newSignalingServer(rawBrokerURL, keepLocalAddresses) if err != nil { - log.Fatalf("invalid broker url: %s", err) + log.Fatal(err) } + _, err = url.Parse(stunURL) if err != nil { log.Fatalf("invalid stun url: %s", err) @@ -580,8 +587,6 @@ func main() { log.Fatalf("invalid relay url: %s", err) }

- broker.transport = http.DefaultTransport.(*http.Transport) - broker.transport.(*http.Transport).ResponseHeaderTimeout = 15 * time.Second config = webrtc.Configuration{ ICEServers: []webrtc.ICEServer{ { @@ -589,17 +594,14 @@ func main() { }, }, } - tokens = make(chan bool, capacity) - for i := uint(0); i < capacity; i++ { - tokens <- true - } + tokens = newTokens(capacity)

// use probetest to determine NAT compatability checkNATType(config, defaultProbeURL) log.Printf("NAT type: %s", currentNATType)

for { - getToken() + tokens.get() sessionID := genSessionID() runSession(sessionID) } @@ -607,12 +609,7 @@ func main() {

func checkNATType(config webrtc.Configuration, probeURL string) {

- var err error - - probe := new(SignalingServer) - probe.transport = http.DefaultTransport.(*http.Transport) - probe.transport.(*http.Transport).ResponseHeaderTimeout = 30 * time.Second - probe.url, err = url.Parse(probeURL) + probe, err := newSignalingServer(probeURL, false) if err != nil { log.Printf("Error parsing url: %s", err.Error()) } diff --git a/proxy/tokens.go b/proxy/tokens.go new file mode 100644 index 0000000..fedb8f7 --- /dev/null +++ b/proxy/tokens.go @@ -0,0 +1,44 @@ +package main + +import ( + "sync/atomic" +) + +type tokens_t struct { + ch chan struct{} + capacity uint + clients int64 +} + +func newTokens(capacity uint) *tokens_t { + var ch chan struct{} + if capacity != 0 { + ch = make(chan struct{}, capacity) + } + + return &tokens_t{ + ch: ch, + capacity: capacity, + clients: 0, + } +} + +func (t *tokens_t) get() { + atomic.AddInt64(&t.clients, 1) + + if t.capacity != 0 { + t.ch <- struct{}{} + } +} + +func (t *tokens_t) ret() { + atomic.AddInt64(&t.clients, -1) + + if t.capacity != 0 { + <-t.ch + } +} + +func (t tokens_t) count() int64 { + return atomic.LoadInt64(&t.clients) +} diff --git a/proxy/tokens_test.go b/proxy/tokens_test.go new file mode 100644 index 0000000..622cc05 --- /dev/null +++ b/proxy/tokens_test.go @@ -0,0 +1,28 @@ +package main + +import ( + "testing" + + . "github.com/smartystreets/goconvey/convey" +) + +func TestTokens(t *testing.T) { + Convey("Tokens", t, func() { + tokens := newTokens(2) + So(tokens.count(), ShouldEqual, 0) + tokens.get() + So(tokens.count(), ShouldEqual, 1) + tokens.ret() + So(tokens.count(), ShouldEqual, 0) + }) + Convey("Tokens capacity 0", t, func() { + tokens := newTokens(0) + So(tokens.count(), ShouldEqual, 0) + for i := 0; i < 20; i++ { + tokens.get() + } + So(tokens.count(), ShouldEqual, 20) + tokens.ret() + So(tokens.count(), ShouldEqual, 19) + }) +}