p2p/discover: pass node instead of node ID to TALKREQ handler

p2p/discover/v5_talk.go

@@ -39,7 +39,7 @@ const talkHandlerLaunchTimeout = 400 * time.Millisecond
 // Note that talk handlers are expected to come up with a response very quickly, within at
 // most 200ms or so. If the handler takes longer than that, the remote end may time out
 // and wont receive the response.
-type TalkRequestHandler func(enode.ID, *net.UDPAddr, []byte) []byte
+type TalkRequestHandler func(*enode.Node, *net.UDPAddr, []byte) []byte
 
 type talkSystem struct {
 	transport *UDPv5
@@ -72,13 +72,19 @@ func (t *talkSystem) register(protocol string, handler TalkRequestHandler) {
 
 // handleRequest handles a talk request.
 func (t *talkSystem) handleRequest(id enode.ID, addr netip.AddrPort, req *v5wire.TalkRequest) {
+	n := t.transport.codec.SessionNode(id, addr.String())
+	if n == nil {
+		// The node must be contained in the session here, since we wouldn't have
+		// received the request otherwise.
+		panic("missing node in session")
+	}
 	t.mutex.Lock()
 	handler, ok := t.handlers[req.Protocol]
 	t.mutex.Unlock()
 
 	if !ok {
 		resp := &v5wire.TalkResponse{ReqID: req.ReqID}
-		t.transport.sendResponse(id, addr, resp)
+		t.transport.sendResponse(n.ID(), addr, resp)
 		return
 	}
 
@@ -90,9 +96,9 @@ func (t *talkSystem) handleRequest(id enode.ID, addr netip.AddrPort, req *v5wire
 		go func() {
 			defer func() { t.slots <- struct{}{} }()
 			udpAddr := &net.UDPAddr{IP: addr.Addr().AsSlice(), Port: int(addr.Port())}
-			respMessage := handler(id, udpAddr, req.Message)
+			respMessage := handler(n, udpAddr, req.Message)
 			resp := &v5wire.TalkResponse{ReqID: req.ReqID, Message: respMessage}
-			t.transport.sendFromAnotherThread(id, addr, resp)
+			t.transport.sendFromAnotherThread(n.ID(), addr, resp)
 		}()
 	case <-timeout.C:
 		// Couldn't get it in time, drop the request.

p2p/discover/v5_udp.go

@@ -64,6 +64,9 @@ type codecV5 interface {
 	// CurrentChallenge returns the most recent WHOAREYOU challenge that was encoded to given node.
 	// This will return a non-nil value if there is an active handshake attempt with the node, and nil otherwise.
 	CurrentChallenge(id enode.ID, addr string) *v5wire.Whoareyou
+
+	// SessionNode returns a node that has completed the handshake.
+	SessionNode(id enode.ID, addr string) *enode.Node
 }
 
 // UDPv5 is the implementation of protocol version 5.

p2p/discover/v5_udp_test.go

@@ -486,7 +486,7 @@ func TestUDPv5_talkHandling(t *testing.T) {
 	defer test.close()
 
 	var recvMessage []byte
-	test.udp.RegisterTalkHandler("test", func(id enode.ID, addr *net.UDPAddr, message []byte) []byte {
+	test.udp.RegisterTalkHandler("test", func(n *enode.Node, addr *net.UDPAddr, message []byte) []byte {
 		recvMessage = message
 		return []byte("test response")
 	})
@@ -795,6 +795,10 @@ func (c *testCodec) Decode(input []byte, addr string) (enode.ID, *enode.Node, v5
 	return frame.NodeID, nil, p, nil
 }
 
+func (c *testCodec) SessionNode(id enode.ID, addr string) *enode.Node {
+	return c.test.nodesByID[id].Node()
+}
+
 func (c *testCodec) decodeFrame(input []byte) (frame testCodecFrame, p v5wire.Packet, err error) {
 	if err = rlp.DecodeBytes(input, &frame); err != nil {
 		return frame, nil, fmt.Errorf("invalid frame: %v", err)

p2p/discover/v5wire/encoding.go

@@ -347,7 +347,7 @@ func (c *Codec) encodeHandshakeHeader(toID enode.ID, addr string, challenge *Who
 	}
 
 	// TODO: this should happen when the first authenticated message is received
-	c.sc.storeNewSession(toID, addr, session)
+	c.sc.storeNewSession(toID, addr, session, challenge.Node)
 
 	// Encode the auth header.
 	var (
@@ -522,7 +522,7 @@ func (c *Codec) decodeHandshakeMessage(fromAddr string, head *Header, headerData
 	}
 
 	// Handshake OK, drop the challenge and store the new session keys.
-	c.sc.storeNewSession(auth.h.SrcID, fromAddr, session)
+	c.sc.storeNewSession(auth.h.SrcID, fromAddr, session, node)
 	c.sc.deleteHandshake(auth.h.SrcID, fromAddr)
 	return node, msg, nil
 }
@@ -644,6 +644,10 @@ func (c *Codec) decryptMessage(input, nonce, headerData, readKey []byte) (Packet
 	return DecodeMessage(msgdata[0], msgdata[1:])
 }
 
+func (c *Codec) SessionNode(id enode.ID, addr string) *enode.Node {
+	return c.sc.readNode(id, addr)
+}
+
 // checkValid performs some basic validity checks on the header.
 // The packetLen here is the length remaining after the static header.
 func (h *StaticHeader) checkValid(packetLen int, protocolID [6]byte) error {

p2p/discover/v5wire/encoding_test.go

@@ -166,7 +166,7 @@ func TestHandshake_rekey(t *testing.T) {
 		readKey:  []byte("BBBBBBBBBBBBBBBB"),
 		writeKey: []byte("AAAAAAAAAAAAAAAA"),
 	}
-	net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), session)
+	net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), session, net.nodeB.n())
 
 	// A -> B   FINDNODE (encrypted with zero keys)
 	findnode, authTag := net.nodeA.encode(t, net.nodeB, &Findnode{})
@@ -209,8 +209,8 @@ func TestHandshake_rekey2(t *testing.T) {
 		readKey:  []byte("CCCCCCCCCCCCCCCC"),
 		writeKey: []byte("DDDDDDDDDDDDDDDD"),
 	}
-	net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), initKeysA)
-	net.nodeB.c.sc.storeNewSession(net.nodeA.id(), net.nodeA.addr(), initKeysB)
+	net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), initKeysA, net.nodeB.n())
+	net.nodeB.c.sc.storeNewSession(net.nodeA.id(), net.nodeA.addr(), initKeysB, net.nodeA.n())
 
 	// A -> B   FINDNODE encrypted with initKeysA
 	findnode, authTag := net.nodeA.encode(t, net.nodeB, &Findnode{Distances: []uint{3}})
@@ -362,8 +362,8 @@ func TestTestVectorsV5(t *testing.T) {
 				ENRSeq: 2,
 			},
 			prep: func(net *handshakeTest) {
-				net.nodeA.c.sc.storeNewSession(idB, addr, session)
-				net.nodeB.c.sc.storeNewSession(idA, addr, session.keysFlipped())
+				net.nodeA.c.sc.storeNewSession(idB, addr, session, net.nodeB.n())
+				net.nodeB.c.sc.storeNewSession(idA, addr, session.keysFlipped(), net.nodeA.n())
 			},
 		},
 		{
@@ -499,8 +499,8 @@ func BenchmarkV5_DecodePing(b *testing.B) {
 		readKey:  []byte{233, 203, 93, 195, 86, 47, 177, 186, 227, 43, 2, 141, 244, 230, 120, 17},
 		writeKey: []byte{79, 145, 252, 171, 167, 216, 252, 161, 208, 190, 176, 106, 214, 39, 178, 134},
 	}
-	net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), session)
-	net.nodeB.c.sc.storeNewSession(net.nodeA.id(), net.nodeA.addr(), session.keysFlipped())
+	net.nodeA.c.sc.storeNewSession(net.nodeB.id(), net.nodeB.addr(), session, net.nodeB.n())
+	net.nodeB.c.sc.storeNewSession(net.nodeA.id(), net.nodeA.addr(), session.keysFlipped(), net.nodeA.n())
 	addrB := net.nodeA.addr()
 	ping := &Ping{ReqID: []byte("reqid"), ENRSeq: 5}
 	enc, _, err := net.nodeA.c.Encode(net.nodeB.id(), addrB, ping, nil)

p2p/discover/v5wire/session.go

@@ -54,11 +54,12 @@ type session struct {
 	writeKey     []byte
 	readKey      []byte
 	nonceCounter uint32
+	node         *enode.Node
 }
 
 // keysFlipped returns a copy of s with the read and write keys flipped.
 func (s *session) keysFlipped() *session {
-	return &session{s.readKey, s.writeKey, s.nonceCounter}
+	return &session{s.readKey, s.writeKey, s.nonceCounter, s.node}
 }
 
 func NewSessionCache(maxItems int, clock mclock.Clock) *SessionCache {
@@ -103,8 +104,19 @@ func (sc *SessionCache) readKey(id enode.ID, addr string) []byte {
 	return nil
 }
 
+func (sc *SessionCache) readNode(id enode.ID, addr string) *enode.Node {
+	if s := sc.session(id, addr); s != nil {
+		return s.node
+	}
+	return nil
+}
+
 // storeNewSession stores new encryption keys in the cache.
-func (sc *SessionCache) storeNewSession(id enode.ID, addr string, s *session) {
+func (sc *SessionCache) storeNewSession(id enode.ID, addr string, s *session, n *enode.Node) {
+	if n == nil {
+		panic("nil node in storeNewSession")
+	}
+	s.node = n
 	sc.sessions.Add(sessionID{id, addr}, s)
 }