whisper: add light mode check to handshake

whisper/whisperv6/api.go

@@ -192,17 +192,17 @@ func (api *PublicWhisperAPI) DeleteSymKey(ctx context.Context, id string) bool {
 	return api.w.DeleteSymKey(id)
 }
 
-// MakeLightClient turns the node into light client, which does not forward
+// MakeLightClient turns the node into pure light client, which does not forward
 // any incoming messages, and sends only messages originated in this node.
 func (api *PublicWhisperAPI) MakeLightClient(ctx context.Context) bool {
-	api.w.lightClient = true
-	return api.w.lightClient
+	api.w.SetLightClientMode(true)
+	return true
 }
 
-// CancelLightClient cancels light client mode.
+// CancelLightClient cancels pure light client mode.
 func (api *PublicWhisperAPI) CancelLightClient(ctx context.Context) bool {
-	api.w.lightClient = false
-	return !api.w.lightClient
+	api.w.SetLightClientMode(false)
+	return true
 }
 
 //go:generate gencodec -type NewMessage -field-override newMessageOverride -out gen_newmessage_json.go

whisper/whisperv6/peer.go

@@ -79,11 +79,13 @@ func (peer *Peer) stop() {
 func (peer *Peer) handshake() error {
 	// Send the handshake status message asynchronously
 	errc := make(chan error, 1)
+	isLightNode := peer.host.LightClientMode()
 	go func() {
 		pow := peer.host.MinPow()
 		powConverted := math.Float64bits(pow)
 		bloom := peer.host.BloomFilter()
-		errc <- p2p.SendItems(peer.ws, statusCode, ProtocolVersion, powConverted, bloom)
+
+		errc <- p2p.SendItems(peer.ws, statusCode, ProtocolVersion, powConverted, bloom, isLightNode)
 	}()
 
 	// Fetch the remote status packet and verify protocol match
@@ -127,6 +129,11 @@ func (peer *Peer) handshake() error {
 		}
 	}
 
+	b, err := s.Bool()
+	if b && isLightNode {
+		return fmt.Errorf("peer [%x]: useless peer: two pure light node communication", peer.ID())
+	}
+
 	if err := <-errc; err != nil {
 		return fmt.Errorf("peer [%x] failed to send status packet: %v", peer.ID(), err)
 	}

whisper/whisperv6/peer_test.go

@@ -33,6 +33,7 @@ import (
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/p2p/discover"
 	"github.com/ethereum/go-ethereum/p2p/nat"
+	"github.com/ethereum/go-ethereum/rlp"
 )
 
 var keys = []string{
@@ -512,3 +513,47 @@ func waitForServersToStart(t *testing.T) {
 	}
 	t.Fatalf("Failed to start all the servers, running: %d", started)
 }
+
+func TestPureLightPeerHandshake(t *testing.T) {
+	w1 := Whisper{}
+	p1 := newPeer(&w1, p2p.NewPeer(discover.NodeID{}, "test", []p2p.Cap{}), &rwStub{[]interface{}{ProtocolVersion, uint64(123), make([]byte, BloomFilterSize), false}})
+	err := p1.handshake()
+	if err != nil {
+		t.Fatal()
+	}
+}
+
+func TestPureLightPeerHandshakeWithOldVersion(t *testing.T) {
+	w1 := Whisper{}
+	p1 := newPeer(&w1, p2p.NewPeer(discover.NodeID{}, "test", []p2p.Cap{}), &rwStub{[]interface{}{ProtocolVersion, uint64(123), make([]byte, BloomFilterSize)}})
+	err := p1.handshake()
+	if err != nil {
+		t.Fatal()
+	}
+}
+
+func TestPureLightPeerHandshakeError(t *testing.T) {
+	w1 := Whisper{}
+	w1.SetLightClientMode(true)
+	p1 := newPeer(&w1, p2p.NewPeer(discover.NodeID{}, "test", []p2p.Cap{}), &rwStub{[]interface{}{ProtocolVersion, uint64(123), make([]byte, BloomFilterSize), true}})
+	err := p1.handshake()
+	if err == nil {
+		t.FailNow()
+	}
+}
+
+type rwStub struct {
+	payload []interface{}
+}
+
+func (stub *rwStub) ReadMsg() (p2p.Msg, error) {
+	size, r, err := rlp.EncodeToReader(stub.payload)
+	if err != nil {
+		return p2p.Msg{}, err
+	}
+	return p2p.Msg{Code: statusCode, Size: uint32(size), Payload: r}, nil
+}
+
+func (stub *rwStub) WriteMsg(m p2p.Msg) error {
+	return nil
+}

whisper/whisperv6/whisper.go

@@ -55,6 +55,7 @@ const (
 	minPowToleranceIdx             // Minimal PoW tolerated by the whisper node for a limited time
 	bloomFilterIdx                 // Bloom filter for topics of interest for this node
 	bloomFilterToleranceIdx        // Bloom filter tolerated by the whisper node for a limited time
+	lightClientModeIdx             // Pure light client mode. (does not forward any messages)
 )
 
 // Whisper represents a dark communication interface through the Ethereum
@@ -82,8 +83,6 @@ type Whisper struct {
 
 	syncAllowance int // maximum time in seconds allowed to process the whisper-related messages
 
-	lightClient bool // indicates is this node is pure light client (does not forward any messages)
-
 	statsMu sync.Mutex // guard stats
 	stats   Statistics // Statistics of whisper node
 
@@ -276,6 +275,24 @@ func (whisper *Whisper) SetMinimumPowTest(val float64) {
 	whisper.settings.Store(minPowToleranceIdx, val)
 }
 
+//SetLightClientMode makes node pure light client (does not forward any messages)
+func (whisper *Whisper) SetLightClientMode(v bool) {
+	whisper.settings.Store(lightClientModeIdx, v)
+}
+
+//LightClientMode indicates is this node is pure light client (does not forward any messages)
+func (whisper *Whisper) LightClientMode() bool {
+	val, exist := whisper.settings.Load(lightClientModeIdx)
+	if !exist || val == nil {
+		return false
+	}
+	v, ok := val.(bool)
+	if !ok {
+		return false
+	}
+	return v
+}
+
 func (whisper *Whisper) notifyPeersAboutPowRequirementChange(pow float64) {
 	arr := whisper.getPeers()
 	for _, p := range arr {
@@ -672,7 +689,7 @@ func (whisper *Whisper) runMessageLoop(p *Peer, rw p2p.MsgReadWriter) error {
 
 			trouble := false
 			for _, env := range envelopes {
-				cached, err := whisper.add(env, whisper.lightClient)
+				cached, err := whisper.add(env, whisper.LightClientMode())
 				if err != nil {
 					trouble = true
 					log.Error("bad envelope received, peer will be disconnected", "peer", p.peer.ID(), "err", err)