multi: Respond to getcfsv2 message.

This adds the appropriate processing to the peer and server structs to
respond to the recently introduced getcfsv2 message.  It also bumps the
peer and server max supported protocol versions to version 10
(BatchedCFiltersV2Version).

This message queries the chain for a batch of committed filters spanning
a set of sequential blocks and will be used by SPV clients to fetch
committed filters during their initial sync process.

peer/go.mod

@@ -12,6 +12,8 @@ require (
 	github.com/decred/slog v1.2.0
 )
 
+replace github.com/decred/dcrd/wire => ../wire
+
 require (
 	github.com/agl/ed25519 v0.0.0-20170116200512-5312a6153412 // indirect
 	github.com/dchest/siphash v1.2.3 // indirect

peer/peer.go

@@ -27,7 +27,7 @@ import (
 
 const (
 	// MaxProtocolVersion is the max protocol version the peer supports.
-	MaxProtocolVersion = wire.RemoveRejectVersion
+	MaxProtocolVersion = wire.BatchedCFiltersV2Version
 
 	// outputBufferSize is the number of elements the output channels use.
 	outputBufferSize = 5000
@@ -128,6 +128,9 @@ type MessageListeners struct {
 	// OnCFilterV2 is invoked when a peer receives a cfilterv2 wire message.
 	OnCFilterV2 func(p *Peer, msg *wire.MsgCFilterV2)
 
+	// OnCFiltersV2 is invoked when a peer receives a cfiltersv2 wire message.
+	OnCFiltersV2 func(p *Peer, msg *wire.MsgCFiltersV2)
+
 	// OnCFHeaders is invoked when a peer receives a cfheaders wire
 	// message.
 	OnCFHeaders func(p *Peer, msg *wire.MsgCFHeaders)
@@ -162,6 +165,10 @@ type MessageListeners struct {
 	// message.
 	OnGetCFilterV2 func(p *Peer, msg *wire.MsgGetCFilterV2)
 
+	// OnGetCFiltersV2 is invoked when a peer receives a getcfsv2 wire
+	// message.
+	OnGetCFiltersV2 func(p *Peer, msg *wire.MsgGetCFiltersV2)
+
 	// OnGetCFHeaders is invoked when a peer receives a getcfheaders
 	// wire message.
 	OnGetCFHeaders func(p *Peer, msg *wire.MsgGetCFHeaders)
@@ -1426,6 +1433,16 @@ out:
 				p.cfg.Listeners.OnCFilterV2(p, msg)
 			}
 
+		case *wire.MsgGetCFiltersV2:
+			if p.cfg.Listeners.OnGetCFiltersV2 != nil {
+				p.cfg.Listeners.OnGetCFiltersV2(p, msg)
+			}
+
+		case *wire.MsgCFiltersV2:
+			if p.cfg.Listeners.OnCFiltersV2 != nil {
+				p.cfg.Listeners.OnCFiltersV2(p, msg)
+			}
+
 		case *wire.MsgGetInitState:
 			if p.cfg.Listeners.OnGetInitState != nil {
 				p.cfg.Listeners.OnGetInitState(p, msg)

peer/peer_test.go

@@ -410,6 +410,12 @@ func TestPeerListeners(t *testing.T) {
 			OnInitState: func(p *Peer, msg *wire.MsgInitState) {
 				ok <- msg
 			},
+			OnGetCFiltersV2: func(p *Peer, msg *wire.MsgGetCFiltersV2) {
+				ok <- msg
+			},
+			OnCFiltersV2: func(p *Peer, msg *wire.MsgCFiltersV2) {
+				ok <- msg
+			},
 		},
 		UserAgentName:    "peer",
 		UserAgentVersion: "1.0",
@@ -564,6 +570,14 @@ func TestPeerListeners(t *testing.T) {
 			"OnInitState",
 			wire.NewMsgInitState(),
 		},
+		{
+			"OnGetCFiltersV2",
+			wire.NewMsgGetCFiltersV2(&chainhash.Hash{}, &chainhash.Hash{}),
+		},
+		{
+			"OnCFiltersV2",
+			wire.NewMsgCFiltersV2([]*wire.MsgCFilterV2{}),
+		},
 	}
 	t.Logf("Running %d tests", len(tests))
 	for _, test := range tests {

server.go

@@ -74,7 +74,7 @@ const (
 	connectionRetryInterval = time.Second * 5
 
 	// maxProtocolVersion is the max protocol version the server supports.
-	maxProtocolVersion = wire.RemoveRejectVersion
+	maxProtocolVersion = wire.BatchedCFiltersV2Version
 
 	// These fields are used to track known addresses on a per-peer basis.
 	//
@@ -1535,6 +1535,16 @@ func (sp *serverPeer) OnGetCFilterV2(_ *peer.Peer, msg *wire.MsgGetCFilterV2) {
 	sp.QueueMessage(filterMsg, nil)
 }
 
+// OnGetCFiltersV2 is invoked when a peer receives a getcfsv2 wire message.
+func (sp *serverPeer) OnGetCFiltersV2(_ *peer.Peer, msg *wire.MsgGetCFiltersV2) {
+	filtersMsg, err := sp.server.chain.LocateCFiltersV2(&msg.StartHash, &msg.EndHash)
+	if err != nil {
+		return
+	}
+
+	sp.QueueMessage(filtersMsg, nil)
+}
+
 // OnGetCFHeaders is invoked when a peer receives a getcfheader wire message.
 func (sp *serverPeer) OnGetCFHeaders(_ *peer.Peer, msg *wire.MsgGetCFHeaders) {
 	// Disconnect and/or ban depending on the node cf services flag and
@@ -2318,6 +2328,7 @@ func newPeerConfig(sp *serverPeer) *peer.Config {
 			OnGetHeaders:     sp.OnGetHeaders,
 			OnGetCFilter:     sp.OnGetCFilter,
 			OnGetCFilterV2:   sp.OnGetCFilterV2,
+			OnGetCFiltersV2:  sp.OnGetCFiltersV2,
 			OnGetCFHeaders:   sp.OnGetCFHeaders,
 			OnGetCFTypes:     sp.OnGetCFTypes,
 			OnGetAddr:        sp.OnGetAddr,