[FAB-1913] Connect to anchor peers at join Channel

When the peer joins a channel it gets a list of anchor peers.
We need the gossip layer to reach out to these anchor peers
and connect to them.

- Added 2 tests (one in the discovery module and one in the gossip module)

I tested this using the following setup:
used docs/docker-compose-channel.yml
And added another peer, and didn't give that peer a bootstrap peer,
so both peers don't know of each other at startup.
Then I created an anchorPeer file with the ip address (172.21.0.4)
and port of one of the peers.
After that, I created a channel with that anchor peer file,
and made the other peer to join the channel.
The peer tried contacting the anchor peer (looked at the gossip communication logs)
and tried authentication with it:
Sending tag:EMPTY signature:"[xxx]" conn:<pkiID:"172.21.0.4:7051" cert:"[yyyyy]" >  to 172.21.0.4:53637
WARN 213 Remote endpoint claims to be a different peer, expected [PEM FILE]
but got [fake PKI-ID I use until MSP is integrated with gossip]

This proves that when joinChannel is called upon a peer with
suitable anchor peer configuration, the peers try to connect
to one another.

Signed-off-by: Yacov Manevich <yacovm@il.ibm.com>
Change-Id: Ia033f81eeaf38cb53cb65dc06a01dca07342386b

Author: yacovm

gossip/discovery/discovery.go

@@ -80,4 +80,7 @@ type Discovery interface {
 	// InitiateSync makes the instance ask a given number of peers
 	// for their membership information
 	InitiateSync(peerNum int)
+
+	// Connect makes this instance to connect to a remote instance
+	Connect(NetworkMember)
 }

gossip/discovery/discovery_impl.go

@@ -133,6 +133,31 @@ func NewDiscoveryService(bootstrapPeers []string, self NetworkMember, comm CommS
 	return d
 }
 
+func (d *gossipDiscoveryImpl) Connect(member NetworkMember) {
+	d.logger.Debug("Entering", member)
+	defer d.logger.Debug("Exiting")
+
+	if member.PKIid == nil {
+		d.logger.Warning("Empty PkiID, aborting")
+		return
+	}
+
+	d.lock.Lock()
+	defer d.lock.Unlock()
+
+	if _, exists := d.id2Member[string(member.PKIid)]; exists {
+		d.logger.Info("Member", member, "already known")
+		return
+	}
+
+	d.deadLastTS[string(member.PKIid)] = &timestamp{
+		incTime:  time.Unix(0, 0),
+		lastSeen: time.Now(),
+		seqNum:   0,
+	}
+	d.id2Member[string(member.PKIid)] = &member
+}
+
 func (d *gossipDiscoveryImpl) connect2BootstrapPeers(endpoints []string) {
 	d.logger.Info("Entering:", endpoints)
 	defer d.logger.Info("Exiting")

gossip/discovery/discovery_test.go

@@ -258,6 +258,28 @@ func bootPeer(port int) string {
 	return fmt.Sprintf("localhost:%d", port)
 }
 
+func TestConnect(t *testing.T) {
+	t.Parallel()
+	nodeNum := 10
+	instances := []*gossipInstance{}
+	for i := 0; i < nodeNum; i++ {
+		inst := createDiscoveryInstance(7611+i, fmt.Sprintf("d%d", i), []string{})
+		instances = append(instances, inst)
+		j := (i + 1) % 10
+		endpoint := fmt.Sprintf("localhost:%d", 7611+j)
+		netMember2Connect2 := NetworkMember{Endpoint: endpoint, PKIid: []byte(endpoint)}
+		inst.Connect(netMember2Connect2)
+		// Check passing nil PKI-ID doesn't crash peer
+		inst.Connect(NetworkMember{PKIid: nil, Endpoint: endpoint})
+	}
+
+	fullMembership := func() bool {
+		return nodeNum-1 == len(instances[nodeNum-1].GetMembership())
+	}
+	waitUntilOrFail(t, fullMembership)
+	stopInstances(t, instances)
+}
+
 func TestUpdate(t *testing.T) {
 	t.Parallel()
 	nodeNum := 5

gossip/gossip/gossip_impl.go

@@ -158,6 +158,24 @@ func (g *gossipServiceImpl) JoinChan(joinMsg api.JoinChannelMessage, chainID com
 		return
 	}
 	g.chanState.joinChannel(joinMsg, chainID)
+
+	selfPkiID := g.mcs.GetPKIidOfCert(g.selfIdentity)
+	for _, ap := range joinMsg.AnchorPeers() {
+		if ap.Host == "" {
+			g.logger.Warning("Got empty hostname, skipping connecting to anchor peer", ap)
+		}
+		if ap.Port == 0 {
+			g.logger.Warning("Got invalid port (0), skipping connecting to anchor peer", ap)
+		}
+		pkiID := g.mcs.GetPKIidOfCert(ap.Cert)
+		// Skip connecting to self
+		if bytes.Equal([]byte(pkiID), []byte(selfPkiID)) {
+			g.logger.Info("Anchor peer with same PKI-ID, skipping connecting to myself")
+			continue
+		}
+		endpoint := fmt.Sprintf("%s:%d", ap.Host, ap.Port)
+		g.disc.Connect(discovery.NetworkMember{Endpoint: endpoint, PKIid: pkiID})
+	}
 }
 
 func (g *gossipServiceImpl) handlePresumedDead() {

gossip/gossip/gossip_test.go

@@ -47,7 +47,7 @@ func init() {
 	discovery.SetExpirationTimeout(aliveTimeInterval * 10)
 	discovery.SetReconnectInterval(aliveTimeInterval * 5)
 
-	testWG.Add(6)
+	testWG.Add(7)
 
 }
 
@@ -63,6 +63,7 @@ func acceptData(m interface{}) bool {
 }
 
 type joinChanMsg struct {
+	anchorPeers []api.AnchorPeer
 }
 
 // SequenceNumber returns the sequence number of the block this joinChanMsg
@@ -72,8 +73,11 @@ func (*joinChanMsg) SequenceNumber() uint64 {
 }
 
 // AnchorPeers returns all the anchor peers that are in the channel
-func (*joinChanMsg) AnchorPeers() []api.AnchorPeer {
-	return []api.AnchorPeer{{Cert: anchorPeerIdentity}}
+func (jcm *joinChanMsg) AnchorPeers() []api.AnchorPeer {
+	if len(jcm.anchorPeers) == 0 {
+		return []api.AnchorPeer{{Cert: anchorPeerIdentity}}
+	}
+	return jcm.anchorPeers
 }
 
 type naiveCryptoService struct {
@@ -281,6 +285,60 @@ func TestPull(t *testing.T) {
 	testWG.Done()
 }
 
+func TestConnectToAnchorPeers(t *testing.T) {
+	t.Parallel()
+	portPrefix := 8610
+	// Scenario: Spawn 5 peers, and make each of them connect to
+	// the other 2 using join channel.
+	stopped := int32(0)
+	go waitForTestCompletion(&stopped, t)
+	n := 5
+
+	jcm := &joinChanMsg{anchorPeers: []api.AnchorPeer{}}
+	for i := 0; i < n; i++ {
+		pkiID := fmt.Sprintf("localhost:%d", portPrefix+i)
+		ap := api.AnchorPeer{
+			Port: portPrefix + i,
+			Host: "localhost",
+			Cert: []byte(pkiID),
+		}
+		jcm.anchorPeers = append(jcm.anchorPeers, ap)
+	}
+
+	peers := make([]Gossip, n)
+	wg := sync.WaitGroup{}
+	for i := 0; i < n; i++ {
+		wg.Add(1)
+		go func(i int) {
+			peers[i] = newGossipInstance(portPrefix, i, 100)
+			peers[i].JoinChan(jcm, common.ChainID("A"))
+			peers[i].UpdateChannelMetadata([]byte("bla bla"), common.ChainID("A"))
+			wg.Done()
+		}(i)
+	}
+	waitUntilOrFailBlocking(t, wg.Wait)
+	waitUntilOrFail(t, checkPeersMembership(peers, n-1))
+
+	channelMembership := func() bool {
+		for _, peer := range peers {
+			if len(peer.PeersOfChannel(common.ChainID("A"))) != n-1 {
+				return false
+			}
+		}
+		return true
+	}
+	waitUntilOrFail(t, channelMembership)
+
+	stop := func() {
+		stopPeers(peers)
+	}
+	waitUntilOrFailBlocking(t, stop)
+
+	fmt.Println("<<<TestConnectToAnchorPeers>>>")
+	atomic.StoreInt32(&stopped, int32(1))
+	testWG.Done()
+}
+
 func TestMembership(t *testing.T) {
 	t.Parallel()
 	portPrefix := 4610