p2p: improve PEX reactor

CHANGELOG_PENDING.md

@@ -57,6 +57,9 @@ Friendly reminder: We have a [bug bounty program](https://hackerone.com/tendermi
 
 - [config] Add `--mode` flag and config variable. See [ADR-52](https://github.com/tendermint/tendermint/blob/master/docs/architecture/adr-052-tendermint-mode.md) @dongsam
 - [rpc] \#6329 Don't cap page size in unsafe mode (@gotjoshua, @cmwaters)
+- [pex] \#6305 v2 pex reactor with backwards compatability. Introduces two new pex messages to
+  accomodate for the new p2p stack. Removes the notion of seeds and crawling. All peer
+  exchange reactors behave the same. (@cmwaters)
 - [crypto] \#6376 Enable sr25519 as a validator key
 
 ### IMPROVEMENTS

blockchain/v0/reactor_test.go

@@ -300,7 +300,10 @@ func TestReactor_BadBlockStopsPeer(t *testing.T) {
 	// XXX: This causes a potential race condition.
 	// See: https://github.com/tendermint/tendermint/issues/6005
 	otherGenDoc, otherPrivVals := randGenesisDoc(config, 1, false, 30)
-	newNode := rts.network.MakeNode(t)
+	newNode := rts.network.MakeNode(t, p2ptest.NodeOptions{
+		MaxPeers:     uint16(len(rts.nodes) + 1),
+		MaxConnected: uint16(len(rts.nodes) + 1),
+	})
 	rts.addNode(t, newNode.NodeID, otherGenDoc, otherPrivVals[0], maxBlockHeight)
 
 	// add a fake peer just so we do not wait for the consensus ticker to timeout

node/node.go

@@ -646,7 +646,7 @@ func createPeerManager(
 	}
 
 	for _, peer := range peers {
-		if err := peerManager.Add(peer); err != nil {
+		if _, err := peerManager.Add(peer); err != nil {
 			return nil, fmt.Errorf("failed to add peer %q: %w", peer, err)
 		}
 	}

p2p/p2ptest/network.go

@@ -30,6 +30,12 @@ type Network struct {
 type NetworkOptions struct {
 	NumNodes   int
 	BufferSize int
+	NodeOpts   NodeOptions
+}
+
+type NodeOptions struct {
+	MaxPeers     uint16
+	MaxConnected uint16
 }
 
 func (opts *NetworkOptions) setDefaults() {
@@ -50,7 +56,7 @@ func MakeNetwork(t *testing.T, opts NetworkOptions) *Network {
 	}
 
 	for i := 0; i < opts.NumNodes; i++ {
-		node := network.MakeNode(t)
+		node := network.MakeNode(t, opts.NodeOpts)
 		network.Nodes[node.NodeID] = node
 	}
 
@@ -81,7 +87,9 @@ func (n *Network) Start(t *testing.T) {
 		for _, targetAddress := range dialQueue[i+1:] { // nodes <i already connected
 			targetNode := n.Nodes[targetAddress.NodeID]
 			targetSub := subs[targetAddress.NodeID]
-			require.NoError(t, sourceNode.PeerManager.Add(targetAddress))
+			added, err := sourceNode.PeerManager.Add(targetAddress)
+			require.NoError(t, err)
+			require.True(t, added)
 
 			select {
 			case peerUpdate := <-sourceSub.Updates():
@@ -107,7 +115,9 @@ func (n *Network) Start(t *testing.T) {
 
 			// Add the address to the target as well, so it's able to dial the
 			// source back if that's even necessary.
-			require.NoError(t, targetNode.PeerManager.Add(sourceAddress))
+			added, err = targetNode.PeerManager.Add(sourceAddress)
+			require.NoError(t, err)
+			require.True(t, added)
 		}
 	}
 }
@@ -214,7 +224,7 @@ type Node struct {
 // MakeNode creates a new Node configured for the network with a
 // running peer manager, but does not add it to the existing
 // network. Callers are responsible for updating peering relationships.
-func (n *Network) MakeNode(t *testing.T) *Node {
+func (n *Network) MakeNode(t *testing.T, opts NodeOptions) *Node {
 	privKey := ed25519.GenPrivKey()
 	nodeID := p2p.NodeIDFromPubKey(privKey.PubKey())
 	nodeInfo := p2p.NodeInfo{
@@ -230,6 +240,8 @@ func (n *Network) MakeNode(t *testing.T) *Node {
 		MinRetryTime:    10 * time.Millisecond,
 		MaxRetryTime:    100 * time.Millisecond,
 		RetryTimeJitter: time.Millisecond,
+		MaxPeers:        opts.MaxPeers,
+		MaxConnected:    opts.MaxConnected,
 	})
 	require.NoError(t, err)
 

p2p/peermanager.go

@@ -384,13 +384,14 @@ func (m *PeerManager) prunePeers() error {
 }
 
 // Add adds a peer to the manager, given as an address. If the peer already
-// exists, the address is added to it if not already present.
-func (m *PeerManager) Add(address NodeAddress) error {
+// exists, the address is added to it if it isn't already present. This will push
+// low scoring peers out of the address book if it exceeds the maximum size.
+func (m *PeerManager) Add(address NodeAddress) (bool, error) {
 	if err := address.Validate(); err != nil {
-		return err
+		return false, err
 	}
 	if address.NodeID == m.selfID {
-		return fmt.Errorf("can't add self (%v) to peer store", m.selfID)
+		return false, fmt.Errorf("can't add self (%v) to peer store", m.selfID)
 	}
 
 	m.mtx.Lock()
@@ -400,17 +401,32 @@ func (m *PeerManager) Add(address NodeAddress) error {
 	if !ok {
 		peer = m.newPeerInfo(address.NodeID)
 	}
-	if _, ok := peer.AddressInfo[address]; !ok {
-		peer.AddressInfo[address] = &peerAddressInfo{Address: address}
+	_, ok = peer.AddressInfo[address]
+	// if we already have the peer address, there's no need to continue
+	if ok {
+		return false, nil
 	}
+
+	// else add the new address
+	peer.AddressInfo[address] = &peerAddressInfo{Address: address}
 	if err := m.store.Set(peer); err != nil {
-		return err
+		return false, err
 	}
 	if err := m.prunePeers(); err != nil {
-		return err
+		return true, err
 	}
 	m.dialWaker.Wake()
-	return nil
+	return true, nil
+}
+
+// PeerRatio returns the ratio of peer addresses stored to the maximum size.
+func (m *PeerManager) PeerRatio() float64 {
+	if m.options.MaxPeers == 0 {
+		return 0
+	}
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+	return float64(m.store.Size()) / float64(m.options.MaxPeers)
 }
 
 // DialNext finds an appropriate peer address to dial, and marks it as dialing.

p2p/peermanager_scoring_test.go

@@ -23,7 +23,9 @@ func TestPeerScoring(t *testing.T) {
 
 	// create a fake node
 	id := NodeID(strings.Repeat("a1", 20))
-	require.NoError(t, peerManager.Add(NodeAddress{NodeID: id, Protocol: "memory"}))
+	added, err := peerManager.Add(NodeAddress{NodeID: id, Protocol: "memory"})
+	require.NoError(t, err)
+	require.True(t, added)
 
 	t.Run("Synchronous", func(t *testing.T) {
 		// update the manager and make sure it's correct