Merge pull request #218 from libp2p/feat/view-last-hop

Expose the peer that propagates a message to the recipient

floodsub_test.go

@@ -1398,3 +1398,59 @@ func readAllQueuedEvents(ctx context.Context, t *testing.T, sub *Subscription) m
 	}
 	return peerState
 }
+
+func TestMessageSender(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	const topic = "foobar"
+
+	hosts := getNetHosts(t, ctx, 3)
+	psubs := getPubsubs(ctx, hosts)
+
+	var msgs []*Subscription
+	for _, ps := range psubs {
+		subch, err := ps.Subscribe(topic)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		msgs = append(msgs, subch)
+	}
+
+	connect(t, hosts[0], hosts[1])
+	connect(t, hosts[1], hosts[2])
+
+	time.Sleep(time.Millisecond * 100)
+
+	for i := 0; i < 3; i++ {
+		for j := 0; j < 100; j++ {
+			msg := []byte(fmt.Sprintf("%d sent %d", i, j))
+
+			psubs[i].Publish(topic, msg)
+
+			for k, sub := range msgs {
+				got, err := sub.Next(ctx)
+				if err != nil {
+					t.Fatal(sub.err)
+				}
+				if !bytes.Equal(msg, got.Data) {
+					t.Fatal("got wrong message!")
+				}
+
+				var expectedHost int
+				if i == k {
+					expectedHost = i
+				} else if k != 1 {
+					expectedHost = 1
+				} else {
+					expectedHost = i
+				}
+
+				if got.ReceivedFrom != hosts[expectedHost].ID() {
+					t.Fatal("got wrong message sender")
+				}
+			}
+		}
+	}
+}

go.mod

@@ -11,3 +11,5 @@ require (
 	github.com/multiformats/go-multistream v0.1.0
 	github.com/whyrusleeping/timecache v0.0.0-20160911033111-cfcb2f1abfee
 )
+
+go 1.13

pubsub.go

@@ -79,7 +79,7 @@ type PubSub struct {
 	topics map[string]map[peer.ID]struct{}
 
 	// sendMsg handles messages that have been validated
-	sendMsg chan *sendReq
+	sendMsg chan *Message
 
 	// addVal handles validator registration requests
 	addVal chan *addValReq
@@ -135,6 +135,7 @@ type PubSubRouter interface {
 
 type Message struct {
 	*pb.Message
+	ReceivedFrom peer.ID
 }
 
 func (m *Message) GetFrom() peer.ID {
@@ -170,7 +171,7 @@ func NewPubSub(ctx context.Context, h host.Host, rt PubSubRouter, opts ...Option
 		getPeers:      make(chan *listPeerReq),
 		addSub:        make(chan *addSubReq),
 		getTopics:     make(chan *topicReq),
-		sendMsg:       make(chan *sendReq, 32),
+		sendMsg:       make(chan *Message, 32),
 		addVal:        make(chan *addValReq),
 		rmVal:         make(chan *rmValReq),
 		eval:          make(chan func()),
@@ -373,10 +374,10 @@ func (p *PubSub) processLoop(ctx context.Context) {
 			p.handleIncomingRPC(rpc)
 
 		case msg := <-p.publish:
-			p.pushMsg(p.host.ID(), msg)
+			p.pushMsg(msg)
 
-		case req := <-p.sendMsg:
-			p.publishMessage(req.from, req.msg.Message)
+		case msg := <-p.sendMsg:
+			p.publishMessage(msg)
 
 		case req := <-p.addVal:
 			p.val.AddValidator(req)
@@ -522,12 +523,12 @@ func (p *PubSub) doAnnounceRetry(pid peer.ID, topic string, sub bool) {
 
 // notifySubs sends a given message to all corresponding subscribers.
 // Only called from processLoop.
-func (p *PubSub) notifySubs(msg *pb.Message) {
+func (p *PubSub) notifySubs(msg *Message) {
 	for _, topic := range msg.GetTopicIDs() {
 		subs := p.myTopics[topic]
 		for f := range subs {
 			select {
-			case f.ch <- &Message{msg}:
+			case f.ch <- msg:
 			default:
 				log.Infof("Can't deliver message to subscription for topic %s; subscriber too slow", topic)
 			}
@@ -616,8 +617,8 @@ func (p *PubSub) handleIncomingRPC(rpc *RPC) {
 			continue
 		}
 
-		msg := &Message{pmsg}
-		p.pushMsg(rpc.from, msg)
+		msg := &Message{pmsg, rpc.from}
+		p.pushMsg(msg)
 	}
 
 	p.rt.HandleRPC(rpc)
@@ -629,7 +630,8 @@ func msgID(pmsg *pb.Message) string {
 }
 
 // pushMsg pushes a message performing validation as necessary
-func (p *PubSub) pushMsg(src peer.ID, msg *Message) {
+func (p *PubSub) pushMsg(msg *Message) {
+	src := msg.ReceivedFrom
 	// reject messages from blacklisted peers
 	if p.blacklist.Contains(src) {
 		log.Warningf("dropping message from blacklisted peer %s", src)
@@ -659,13 +661,13 @@ func (p *PubSub) pushMsg(src peer.ID, msg *Message) {
 	}
 
 	if p.markSeen(id) {
-		p.publishMessage(src, msg.Message)
+		p.publishMessage(msg)
 	}
 }
 
-func (p *PubSub) publishMessage(from peer.ID, pmsg *pb.Message) {
-	p.notifySubs(pmsg)
-	p.rt.Publish(from, pmsg)
+func (p *PubSub) publishMessage(msg *Message) {
+	p.notifySubs(msg)
+	p.rt.Publish(msg.ReceivedFrom, msg.Message)
 }
 
 type addSubReq struct {
@@ -734,10 +736,11 @@ func (p *PubSub) GetTopics() []string {
 // Publish publishes data to the given topic.
 func (p *PubSub) Publish(topic string, data []byte) error {
 	seqno := p.nextSeqno()
+	id := p.host.ID()
 	m := &pb.Message{
 		Data:     data,
 		TopicIDs: []string{topic},
-		From:     []byte(p.host.ID()),
+		From:     []byte(id),
 		Seqno:    seqno,
 	}
 	if p.signKey != nil {
@@ -747,7 +750,7 @@ func (p *PubSub) Publish(topic string, data []byte) error {
 			return err
 		}
 	}
-	p.publish <- &Message{m}
+	p.publish <- &Message{m, id}
 	return nil
 }
 
@@ -763,13 +766,6 @@ type listPeerReq struct {
 	topic string
 }
 
-// sendReq is a request to call publishMessage.
-// It is issued after message validation is done.
-type sendReq struct {
-	from peer.ID
-	msg  *Message
-}
-
 // ListPeers returns a list of peers we are connected to in the given topic.
 func (p *PubSub) ListPeers(topic string) []peer.ID {
 	out := make(chan []peer.ID)

validation.go

@@ -233,10 +233,7 @@ func (v *validation) validate(vals []*topicVal, src peer.ID, msg *Message) {
 	}
 
 	// no async validators, send the message
-	v.p.sendMsg <- &sendReq{
-		from: src,
-		msg:  msg,
-	}
+	v.p.sendMsg <- msg
 }
 
 func (v *validation) validateSignature(msg *Message) bool {
@@ -255,10 +252,7 @@ func (v *validation) doValidateTopic(vals []*topicVal, src peer.ID, msg *Message
 		return
 	}
 
-	v.p.sendMsg <- &sendReq{
-		from: src,
-		msg:  msg,
-	}
+	v.p.sendMsg <- msg
 }
 
 func (v *validation) validateTopic(vals []*topicVal, src peer.ID, msg *Message) bool {