les, p2p/simulations/adapters: fix issues found while simulating les (#21761)

This adds a few tiny fixes for les and the p2p simulation framework:

LES Parts

- Keep the LES-SERVER connection even it's non-synced

  We had this idea to reject the connections in LES protocol if the les-server itself is
  not synced. However, in LES protocol we will also receive the connection from another
  les-server. In this case even the local node is not synced yet, we should keep the tcp
  connection for other protocols(e.g. eth protocol).

- Don't count "invalid message" for non-existing GetBlockHeadersMsg request

  In the eth syncing mechanism (full sync, fast sync, light sync), it will try to fetch
  some non-existent blocks or headers(to ensure we indeed download all the missing chain).
  In this case, it's possible that the les-server will receive the request for
  non-existent headers. So don't count it as the "invalid message" for scheduling
  dropping.

- Copy the announce object in the closure

  Before the les-server pushes the latest headers to all connected clients, it will create
  a closure and queue it in the underlying request scheduler. In some scenarios it's
  problematic. E.g, in private networks, the block can be mined very fast. So before the
  first closure is executed, we may already update the latest_announce object. So actually
  the "announce" object we want to send is replaced.

  The downsize is the client will receive two announces with the same td and then drop the
  server.

P2P Simulation Framework

- Don't double register the protocol services in p2p-simulation "Start".

  The protocols upon the devp2p are registered in the "New node stage". So don't reigster
  them again when starting a node in the p2p simulation framework

- Add one more new config field "ExternalSigner", in order to use clef service in the
  framework.

les/server_handler.go

@@ -126,11 +126,7 @@ func (h *serverHandler) handle(p *clientPeer) error {
 		p.Log().Debug("Light Ethereum handshake failed", "err", err)
 		return err
 	}
-	// Reject light clients if server is not synced.
+	// Reject the duplicated peer, otherwise register it to peerset.
-	if !h.synced() {
-		p.Log().Debug("Light server not synced, rejecting peer")
-		return p2p.DiscRequested
-	}
 	var registered bool
 	if err := h.server.ns.Operation(func() {
 		if h.server.ns.GetField(p.Node(), clientPeerField) != nil {
@@ -156,7 +152,14 @@ func (h *serverHandler) handle(p *clientPeer) error {
 		_, err := p.rw.ReadMsg()
 		return err
 	}
-
+	// Reject light clients if server is not synced.
+	//
+	// Put this checking here, so that "non-synced" les-server peers are still allowed
+	// to keep the connection.
+	if !h.synced() {
+		p.Log().Debug("Light server not synced, rejecting peer")
+		return p2p.DiscRequested
+	}
 	// Disconnect the inbound peer if it's rejected by clientPool
 	if cap, err := h.server.clientPool.connect(p); cap != p.fcParams.MinRecharge || err != nil {
 		p.Log().Debug("Light Ethereum peer rejected", "err", errFullClientPool)
@@ -348,7 +351,6 @@ func (h *serverHandler) handleMsg(p *clientPeer, wg *sync.WaitGroup) error {
 						origin = h.blockchain.GetHeaderByNumber(query.Origin.Number)
 					}
 					if origin == nil {
-						p.bumpInvalid()
 						break
 					}
 					headers = append(headers, origin)
@@ -1006,18 +1008,24 @@ func (b *broadcaster) sendTo(node *enode.Node) {
 	}
 	if p, _ := b.ns.GetField(node, clientPeerField).(*clientPeer); p != nil {
 		if p.headInfo.Td == nil || b.lastAnnounce.Td.Cmp(p.headInfo.Td) > 0 {
+			announce := b.lastAnnounce
 			switch p.announceType {
 			case announceTypeSimple:
-				if !p.queueSend(func() { p.sendAnnounce(b.lastAnnounce) }) {
+				if !p.queueSend(func() { p.sendAnnounce(announce) }) {
-					log.Debug("Drop announcement because queue is full", "number", b.lastAnnounce.Number, "hash", b.lastAnnounce.Hash)
+					log.Debug("Drop announcement because queue is full", "number", announce.Number, "hash", announce.Hash)
+				} else {
+					log.Debug("Sent announcement", "number", announce.Number, "hash", announce.Hash)
 				}
 			case announceTypeSigned:
 				if b.signedAnnounce.Hash != b.lastAnnounce.Hash {
 					b.signedAnnounce = b.lastAnnounce
 					b.signedAnnounce.sign(b.privateKey)
 				}
-				if !p.queueSend(func() { p.sendAnnounce(b.signedAnnounce) }) {
+				announce := b.signedAnnounce
-					log.Debug("Drop announcement because queue is full", "number", b.lastAnnounce.Number, "hash", b.lastAnnounce.Hash)
+				if !p.queueSend(func() { p.sendAnnounce(announce) }) {
+					log.Debug("Drop announcement because queue is full", "number", announce.Number, "hash", announce.Hash)
+				} else {
+					log.Debug("Sent announcement", "number", announce.Number, "hash", announce.Hash)
 				}
 			}
 			p.headInfo = blockInfo{b.lastAnnounce.Hash, b.lastAnnounce.Number, b.lastAnnounce.Td}

p2p/simulations/adapters/inproc.go

@@ -99,6 +99,7 @@ func (s *SimAdapter) NewNode(config *NodeConfig) (Node, error) {
 			Dialer:          s,
 			EnableMsgEvents: config.EnableMsgEvents,
 		},
+		ExternalSigner: config.ExternalSigner,
 		NoUSB:          true,
 		Logger:         log.New("node.id", id.String()),
 	})
@@ -263,7 +264,6 @@ func (sn *SimNode) Start(snapshots map[string][]byte) error {
 				continue
 			}
 			sn.running[name] = service
-			sn.node.RegisterLifecycle(service)
 		}
 	})
 	if regErr != nil {

p2p/simulations/adapters/types.go

@@ -107,6 +107,9 @@ type NodeConfig struct {
 	// These values need to be checked and acted upon by node Services
 	Properties []string
 
+	// ExternalSigner specifies an external URI for a clef-type signer
+	ExternalSigner string
+
 	// Enode
 	node *enode.Node