fix: count observations with at least one inbound connection as inbound

We prefer addresses from inbound connections. We don't want outbound connections
to hide these perfectly good addresses.

p2p/protocol/identify/obsaddr.go

@@ -37,7 +37,7 @@ var maxObservedAddrsPerIPAndTransport = 2
 
 type observation struct {
 	seenTime time.Time
-	connDirection network.Direction
+	inbound  bool
 }
 
 // observedAddr is an entry for an address reported by our peers.
@@ -62,7 +62,7 @@ func (oa *observedAddr) activated() bool {
 func (oa *observedAddr) numInbound() int {
 	count := 0
 	for obs := range oa.seenBy {
-		if oa.seenBy[obs].connDirection == network.DirInbound {
+		if oa.seenBy[obs].inbound {
 			count++
 		}
 	}
@@ -383,15 +383,18 @@ func (oas *ObservedAddrManager) recordObservationUnlocked(conn network.Conn, obs
 	localString := string(conn.LocalMultiaddr().Bytes())
 	ob := observation{
 		seenTime: now,
-		connDirection: conn.Stat().Direction,
+		inbound:  conn.Stat().Direction == network.DirInbound,
 	}
 
-	observedAddrs := oas.addrs[localString]
 	// check if observed address seen yet, if so, update it
-	for i, previousObserved := range observedAddrs {
-		if previousObserved.addr.Equal(observed) {
-			observedAddrs[i].seenBy[observerString] = ob
-			observedAddrs[i].lastSeen = now
+	for _, observedAddr := range oas.addrs[localString] {
+		if observedAddr.addr.Equal(observed) {
+			// Don't trump an outbound observation with an inbound
+			// one.
+			ob.inbound = ob.inbound || observedAddr.seenBy[observerString].inbound
+
+			observedAddr.seenBy[observerString] = ob
+			observedAddr.lastSeen = now
 			return
 		}
 	}

p2p/protocol/identify/obsaddr_test.go

@@ -49,6 +49,22 @@ func (h *harness) conn(observer peer.ID) network.Conn {
 	if err != nil {
 		h.t.Fatal(err)
 	}
+	if c.Stat().Direction != network.DirOutbound {
+		h.t.Fatal("expected conn direction to be outbound")
+	}
+	return c
+}
+
+func (h *harness) connInbound(observer peer.ID) network.Conn {
+	c, err := h.mocknet.ConnectPeers(observer, h.host.ID())
+	if err != nil {
+		h.t.Fatal(err)
+	}
+
+	c = mocknet.ConnComplement(c)
+	if c.Stat().Direction != network.DirInbound {
+		h.t.Fatal("expected conn direction to be inbound")
+	}
 	return c
 }
 
@@ -59,6 +75,13 @@ func (h *harness) observe(observed ma.Multiaddr, observer peer.ID) network.Conn
 	return c
 }
 
+func (h *harness) observeInbound(observed ma.Multiaddr, observer peer.ID) network.Conn {
+	c := h.connInbound(observer)
+	h.oas.Record(c, observed)
+	time.Sleep(50 * time.Millisecond) // let the worker run
+	return c
+}
+
 func newHarness(ctx context.Context, t *testing.T) harness {
 	mn := mocknet.New(ctx)
 	sk, err := p2putil.RandTestBogusPrivateKey()
@@ -75,6 +98,7 @@ func newHarness(ctx context.Context, t *testing.T) harness {
 		oas:     identify.NewObservedAddrManager(ctx, h),
 		mocknet: mn,
 		host:    h,
+		t:       t,
 	}
 }
 
@@ -292,7 +316,28 @@ func TestObservedAddrFiltering(t *testing.T) {
 	b4 := ma.StringCast("/ip4/1.2.3.9/tcp/1237")
 	b5 := ma.StringCast("/ip4/1.2.3.10/tcp/1237")
 
-	peers := []peer.ID{harness.add(b1), harness.add(b2), harness.add(b3), harness.add(b4), harness.add(b5)}
+	b6 := ma.StringCast("/ip4/1.2.3.11/tcp/1237")
+	b7 := ma.StringCast("/ip4/1.2.3.12/tcp/1237")
+
+	// These are all observers in the same group.
+	b8 := ma.StringCast("/ip4/1.2.3.13/tcp/1237")
+	b9 := ma.StringCast("/ip4/1.2.3.13/tcp/1238")
+	b10 := ma.StringCast("/ip4/1.2.3.13/tcp/1239")
+
+	peers := []peer.ID{
+		harness.add(b1),
+		harness.add(b2),
+		harness.add(b3),
+		harness.add(b4),
+		harness.add(b5),
+
+		harness.add(b6),
+		harness.add(b7),
+
+		harness.add(b8),
+		harness.add(b9),
+		harness.add(b10),
+	}
 	for i := 0; i < 4; i++ {
 		harness.observe(it1, peers[i])
 		harness.observe(it2, peers[i])
@@ -311,4 +356,41 @@ func TestObservedAddrFiltering(t *testing.T) {
 	require.Contains(t, addrs, it1)
 	require.Contains(t, addrs, it7)
 
+	// Bump the number of observations so 1 & 7 have 7 observations.
+	harness.observe(it1, peers[5])
+	harness.observe(it1, peers[6])
+	harness.observe(it7, peers[5])
+	harness.observe(it7, peers[6])
+
+	// Add an observation from IP 1.2.3.13
+	// 2 & 3 now have 5 observations
+	harness.observe(it2, peers[7])
+	harness.observe(it3, peers[7])
+
+	addrs = harness.oas.Addrs()
+	require.Len(t, addrs, 2)
+	require.Contains(t, addrs, it1)
+	require.Contains(t, addrs, it7)
+
+	// Add an inbound observation from IP 1.2.3.13, it should override the
+	// existing observation and it should make these addresses win even
+	// though we have fewer observations.
+	//
+	// 2 & 3 now have 6 observations.
+	harness.observeInbound(it2, peers[8])
+	harness.observeInbound(it3, peers[8])
+	addrs = harness.oas.Addrs()
+	require.Len(t, addrs, 2)
+	require.Contains(t, addrs, it2)
+	require.Contains(t, addrs, it3)
+
+	// Adding an outbound observation shouldn't "downgrade" it.
+	//
+	// 2 & 3 now have 7 observations.
+	harness.observe(it2, peers[9])
+	harness.observe(it3, peers[9])
+	addrs = harness.oas.Addrs()
+	require.Len(t, addrs, 2)
+	require.Contains(t, addrs, it2)
+	require.Contains(t, addrs, it3)
 }