Get rid of legacy version

Move the logic for the legacy version into the http handlers and use a
shim when doing ipc.

broker/http.go

@@ -102,7 +102,6 @@ func proxyPolls(i *IPC, w http.ResponseWriter, r *http.Request) {
 	arg := messages.Arg{
 		Body:       body,
 		RemoteAddr: r.RemoteAddr,
-		NatType:    "",
 	}
 
 	var response []byte
@@ -138,28 +137,57 @@ func clientOffers(i *IPC, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Handle the legacy version
+	isLegacy := false
+	if len(body) > 0 && body[0] == '{' {
+		isLegacy = true
+		req := messages.ClientPollRequest{
+			Offer: string(body),
+			NAT:   r.Header.Get("Snowflake-NAT-Type"),
+		}
+		body, err = req.EncodePollRequest()
+		if err != nil {
+			log.Printf("Error shimming the legacy request: %s", err.Error())
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+	}
+
 	arg := messages.Arg{
 		Body:       body,
 		RemoteAddr: "",
-		NatType:    r.Header.Get("Snowflake-NAT-Type"),
 	}
 
 	var response []byte
 	err = i.ClientOffers(arg, &response)
-	switch {
+	if err != nil {
-	case err == nil:
+		// Assert err == messages.ErrInternal
-	case errors.Is(err, messages.ErrUnavailable):
-		w.WriteHeader(http.StatusServiceUnavailable)
-		return
-	case errors.Is(err, messages.ErrTimeout):
-		w.WriteHeader(http.StatusGatewayTimeout)
-		return
-	default:
 		log.Println(err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
 
+	if isLegacy {
+		resp, err := messages.DecodeClientPollResponse(response)
+		if err != nil {
+			log.Println(err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		switch resp.Error {
+		case "":
+			response = []byte(resp.Answer)
+		case "no snowflake proxies currently available":
+			w.WriteHeader(http.StatusServiceUnavailable)
+			return
+		case "timed out waiting for answer!":
+			w.WriteHeader(http.StatusGatewayTimeout)
+			return
+		default:
+			panic("unknown error")
+		}
+	}
+
 	if _, err := w.Write(response); err != nil {
 		log.Printf("clientOffers unable to write answer with error: %v", err)
 	}
@@ -181,7 +209,6 @@ func proxyAnswers(i *IPC, w http.ResponseWriter, r *http.Request) {
 	arg := messages.Arg{
 		Body:       body,
 		RemoteAddr: "",
-		NatType:    "",
 	}
 
 	var response []byte

broker/ipc.go

@@ -21,14 +21,10 @@ const (
 	NATUnrestricted = "unrestricted"
 )
 
-// We support two client message formats. The legacy format is for backwards
-// combatability and relies heavily on HTTP headers and status codes to convey
-// information.
 type clientVersion int
 
 const (
-	v0 clientVersion = iota //legacy version
+	v1 clientVersion = iota
-	v1
 )
 
 type IPC struct {
@@ -141,32 +137,22 @@ func (i *IPC) ClientOffers(arg messages.Arg, response *[]byte) error {
 	startTime := time.Now()
 	body := arg.Body
 
-	if len(body) > 0 && body[0] == '{' {
+	parts := bytes.SplitN(body, []byte("\n"), 2)
-		version = v0
+	if len(parts) < 2 {
+		// no version number found
+		err := fmt.Errorf("unsupported message version")
+		return sendClientResponse(&messages.ClientPollResponse{Error: err.Error()}, response)
+	}
+	body = parts[1]
+	if string(parts[0]) == "1.0" {
+		version = v1
 	} else {
-		parts := bytes.SplitN(body, []byte("\n"), 2)
+		err := fmt.Errorf("unsupported message version")
-		if len(parts) < 2 {
+		return sendClientResponse(&messages.ClientPollResponse{Error: err.Error()}, response)
-			// no version number found
-			err := fmt.Errorf("unsupported message version")
-			return sendClientResponse(&messages.ClientPollResponse{Error: err.Error()}, response)
-		}
-		body = parts[1]
-		if string(parts[0]) == "1.0" {
-			version = v1
-
-		} else {
-			err := fmt.Errorf("unsupported message version")
-			return sendClientResponse(&messages.ClientPollResponse{Error: err.Error()}, response)
-		}
 	}
 
 	var offer *ClientOffer
 	switch version {
-	case v0:
-		offer = &ClientOffer{
-			natType: arg.NatType,
-			sdp:     body,
-		}
 	case v1:
 		req, err := messages.DecodeClientPollRequest(body)
 		if err != nil {
@@ -203,8 +189,6 @@ func (i *IPC) ClientOffers(arg messages.Arg, response *[]byte) error {
 		}
 		i.ctx.metrics.lock.Unlock()
 		switch version {
-		case v0:
-			return messages.ErrUnavailable
 		case v1:
 			resp := &messages.ClientPollResponse{Error: "no snowflake proxies currently available"}
 			return sendClientResponse(resp, response)
@@ -230,8 +214,6 @@ func (i *IPC) ClientOffers(arg messages.Arg, response *[]byte) error {
 		i.ctx.metrics.promMetrics.ClientPollTotal.With(prometheus.Labels{"nat": offer.natType, "status": "matched"}).Inc()
 		i.ctx.metrics.lock.Unlock()
 		switch version {
-		case v0:
-			*response = []byte(answer)
 		case v1:
 			resp := &messages.ClientPollResponse{Answer: answer}
 			err = sendClientResponse(resp, response)
@@ -243,8 +225,6 @@ func (i *IPC) ClientOffers(arg messages.Arg, response *[]byte) error {
 	case <-time.After(time.Second * ClientTimeout):
 		log.Println("Client: Timed out.")
 		switch version {
-		case v0:
-			err = messages.ErrTimeout
 		case v1:
 			resp := &messages.ClientPollResponse{
 				Error: "timed out waiting for answer!"}

common/messages/ipc.go

@@ -7,12 +7,9 @@ import (
 type Arg struct {
 	Body       []byte
 	RemoteAddr string
-	NatType    string
 }
 
 var (
-	ErrBadRequest  = errors.New("bad request")
+	ErrBadRequest = errors.New("bad request")
-	ErrInternal    = errors.New("internal error")
+	ErrInternal   = errors.New("internal error")
-	ErrUnavailable = errors.New("service unavailable")
-	ErrTimeout     = errors.New("timeout")
 )