whisper: add light mode check to handshake (ethereum#16725)

cmd/geth/config.go

@@ -168,6 +168,9 @@ func makeFullNode(ctx *cli.Context) *node.Node {
 		if ctx.GlobalIsSet(utils.WhisperMinPOWFlag.Name) {
 			cfg.Shh.MinimumAcceptedPOW = ctx.Float64(utils.WhisperMinPOWFlag.Name)
 		}
+		if ctx.GlobalIsSet(utils.WhisperRestrictConnectionBetweenLightClientsFlag.Name) {
+			cfg.Shh.RestrictConnectionBetweenLightClients = true
+		}
 		utils.RegisterShhService(stack, &cfg.Shh)
 	}
 

cmd/geth/main.go

@@ -151,6 +151,7 @@ var (
 		utils.WhisperEnabledFlag,
 		utils.WhisperMaxMessageSizeFlag,
 		utils.WhisperMinPOWFlag,
+		utils.WhisperRestrictConnectionBetweenLightClientsFlag,
 	}
 
 	metricsFlags = []cli.Flag{

cmd/utils/flags.go

@@ -567,6 +567,10 @@ var (
 		Usage: "Minimum POW accepted",
 		Value: whisper.DefaultMinimumPoW,
 	}
+	WhisperRestrictConnectionBetweenLightClientsFlag = cli.BoolFlag{
+		Name:  "shh.restrict-light",
+		Usage: "Restrict connection between two whisper light clients",
+	}
 
 	// Metrics flags
 	MetricsEnabledFlag = cli.BoolFlag{
@@ -1099,6 +1103,9 @@ func SetShhConfig(ctx *cli.Context, stack *node.Node, cfg *whisper.Config) {
 	if ctx.GlobalIsSet(WhisperMinPOWFlag.Name) {
 		cfg.MinimumAcceptedPOW = ctx.GlobalFloat64(WhisperMinPOWFlag.Name)
 	}
+	if ctx.GlobalIsSet(WhisperRestrictConnectionBetweenLightClientsFlag.Name) {
+		cfg.RestrictConnectionBetweenLightClients = true
+	}
 }
 
 // SetEthConfig applies eth-related command line flags to the config.

whisper/whisperv6/api.go

@@ -195,14 +195,14 @@ func (api *PublicWhisperAPI) DeleteSymKey(ctx context.Context, id string) bool {
 // MakeLightClient turns the node into 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 api.w.LightClientMode()
 }
 
 // CancelLightClient cancels light client mode.
 func (api *PublicWhisperAPI) CancelLightClient(ctx context.Context) bool {
-	api.w.lightClient = false
-	return !api.w.lightClient
+	api.w.SetLightClientMode(false)
+	return !api.w.LightClientMode()
 }
 
 //go:generate gencodec -type NewMessage -field-override newMessageOverride -out gen_newmessage_json.go

whisper/whisperv6/config.go

@@ -18,12 +18,14 @@ package whisperv6
 
 // Config represents the configuration state of a whisper node.
 type Config struct {
-	MaxMessageSize     uint32  `toml:",omitempty"`
-	MinimumAcceptedPOW float64 `toml:",omitempty"`
+	MaxMessageSize                        uint32  `toml:",omitempty"`
+	MinimumAcceptedPOW                    float64 `toml:",omitempty"`
+	RestrictConnectionBetweenLightClients bool    `toml:",omitempty"`
 }
 
 // DefaultConfig represents (shocker!) the default configuration.
 var DefaultConfig = Config{
-	MaxMessageSize:     DefaultMaxMessageSize,
-	MinimumAcceptedPOW: DefaultMinimumPoW,
+	MaxMessageSize:                        DefaultMaxMessageSize,
+	MinimumAcceptedPOW:                    DefaultMinimumPoW,
+	RestrictConnectionBetweenLightClients: true,
 }

whisper/whisperv6/peer.go

@@ -79,11 +79,14 @@ func (peer *Peer) stop() {
 func (peer *Peer) handshake() error {
 	// Send the handshake status message asynchronously
 	errc := make(chan error, 1)
+	isLightNode := peer.host.LightClientMode()
+	isRestrictedLightNodeConnection := peer.host.LightClientModeConnectionRestricted()
 	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 +130,11 @@ func (peer *Peer) handshake() error {
 		}
 	}
 
+	isRemotePeerLightNode, err := s.Bool()
+	if isRemotePeerLightNode && isLightNode && isRestrictedLightNodeConnection {
+		return fmt.Errorf("peer [%x] is useless: two light client communication restricted", 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

@@ -34,6 +34,7 @@ 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{
@@ -507,3 +508,63 @@ func waitForServersToStart(t *testing.T) {
 	}
 	t.Fatalf("Failed to start all the servers, running: %d", started)
 }
+
+//two generic whisper node handshake
+func TestPeerHandshakeWithTwoFullNode(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()
+	}
+}
+
+//two generic whisper node handshake. one don't send light flag
+func TestHandshakeWithOldVersionWithoutLightModeFlag(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()
+	}
+}
+
+//two light nodes handshake. restriction disabled
+func TestTwoLightPeerHandshakeRestrictionOff(t *testing.T) {
+	w1 := Whisper{}
+	w1.settings.Store(restrictConnectionBetweenLightClientsIdx, false)
+	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()
+	}
+}
+
+//two light nodes handshake. restriction enabled
+func TestTwoLightPeerHandshakeError(t *testing.T) {
+	w1 := Whisper{}
+	w1.settings.Store(restrictConnectionBetweenLightClientsIdx, true)
+	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

@@ -49,12 +49,14 @@ type Statistics struct {
 }
 
 const (
-	maxMsgSizeIdx           = iota // Maximal message length allowed by the whisper node
-	overflowIdx                    // Indicator of message queue overflow
-	minPowIdx                      // Minimal PoW required by the whisper node
-	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
+	maxMsgSizeIdx                            = iota // Maximal message length allowed by the whisper node
+	overflowIdx                                     // Indicator of message queue overflow
+	minPowIdx                                       // Minimal PoW required by the whisper node
+	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                              // Light client mode. (does not forward any messages)
+	restrictConnectionBetweenLightClientsIdx        // Restrict connection between two light clients
 )
 
 // Whisper represents a dark communication interface through the Ethereum
@@ -82,8 +84,6 @@ 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
 
@@ -113,6 +113,7 @@ func New(cfg *Config) *Whisper {
 	whisper.settings.Store(minPowIdx, cfg.MinimumAcceptedPOW)
 	whisper.settings.Store(maxMsgSizeIdx, cfg.MaxMessageSize)
 	whisper.settings.Store(overflowIdx, false)
+	whisper.settings.Store(restrictConnectionBetweenLightClientsIdx, cfg.RestrictConnectionBetweenLightClients)
 
 	// p2p whisper sub protocol handler
 	whisper.protocol = p2p.Protocol{
@@ -276,6 +277,31 @@ func (whisper *Whisper) SetMinimumPowTest(val float64) {
 	whisper.settings.Store(minPowToleranceIdx, val)
 }
 
+//SetLightClientMode makes node light client (does not forward any messages)
+func (whisper *Whisper) SetLightClientMode(v bool) {
+	whisper.settings.Store(lightClientModeIdx, v)
+}
+
+//LightClientMode indicates is this node is 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)
+	return v && ok
+}
+
+//LightClientModeConnectionRestricted indicates that connection to light client in light client mode not allowed
+func (whisper *Whisper) LightClientModeConnectionRestricted() bool {
+	val, exist := whisper.settings.Load(restrictConnectionBetweenLightClientsIdx)
+	if !exist || val == nil {
+		return false
+	}
+	v, ok := val.(bool)
+	return v && ok
+}
+
 func (whisper *Whisper) notifyPeersAboutPowRequirementChange(pow float64) {
 	arr := whisper.getPeers()
 	for _, p := range arr {
@@ -672,7 +698,7 @@ 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)