p2p, p2p/discover, p2p/discv5: implement UDP port sharing

cmd/bootnode/main.go

@@ -21,6 +21,7 @@ import (
 	"crypto/ecdsa"
 	"flag"
 	"fmt"
+	"net"
 	"os"
 
 	"github.com/ethereum/go-ethereum/cmd/utils"
@@ -96,12 +97,32 @@ func main() {
 		}
 	}
 
+	addr, err := net.ResolveUDPAddr("udp", *listenAddr)
+	if err != nil {
+		utils.Fatalf("-ResolveUDPAddr: %v", err)
+	}
+	conn, err := net.ListenUDP("udp", addr)
+	if err != nil {
+		utils.Fatalf("-ListenUDP: %v", err)
+	}
+
+	realaddr := conn.LocalAddr().(*net.UDPAddr)
+	if natm != nil {
+		if !realaddr.IP.IsLoopback() {
+			go nat.Map(natm, nil, "udp", realaddr.Port, realaddr.Port, "ethereum discovery")
+		}
+		// TODO: react to external IP changes over time.
+		if ext, err := natm.ExternalIP(); err == nil {
+			realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
+		}
+	}
+
 	if *runv5 {
-		if _, err := discv5.ListenUDP(nodeKey, *listenAddr, natm, "", restrictList); err != nil {
+		if _, err := discv5.ListenUDP(nodeKey, conn, realaddr, "", restrictList); err != nil {
 			utils.Fatalf("%v", err)
 		}
 	} else {
-		if _, err := discover.ListenUDP(nodeKey, *listenAddr, natm, "", restrictList); err != nil {
+		if _, err := discover.ListenUDP(nodeKey, conn, realaddr, nil, "", restrictList); err != nil {
 			utils.Fatalf("%v", err)
 		}
 	}

cmd/faucet/faucet.go

@@ -223,7 +223,6 @@ func newFaucet(genesis *core.Genesis, port int, enodes []*discv5.Node, network u
 			NoDiscovery:      true,
 			DiscoveryV5:      true,
 			ListenAddr:       fmt.Sprintf(":%d", port),
-			DiscoveryV5Addr:  fmt.Sprintf(":%d", port+1),
 			MaxPeers:         25,
 			BootstrapNodesV5: enodes,
 		},

cmd/utils/flags.go

@@ -635,14 +635,6 @@ func setListenAddress(ctx *cli.Context, cfg *p2p.Config) {
 	}
 }
 
-// setDiscoveryV5Address creates a UDP listening address string from set command
-// line flags for the V5 discovery protocol.
-func setDiscoveryV5Address(ctx *cli.Context, cfg *p2p.Config) {
-	if ctx.GlobalIsSet(ListenPortFlag.Name) {
-		cfg.DiscoveryV5Addr = fmt.Sprintf(":%d", ctx.GlobalInt(ListenPortFlag.Name)+1)
-	}
-}
-
 // setNAT creates a port mapper from command line flags.
 func setNAT(ctx *cli.Context, cfg *p2p.Config) {
 	if ctx.GlobalIsSet(NATFlag.Name) {
@@ -793,7 +785,6 @@ func SetP2PConfig(ctx *cli.Context, cfg *p2p.Config) {
 	setNodeKey(ctx, cfg)
 	setNAT(ctx, cfg)
 	setListenAddress(ctx, cfg)
-	setDiscoveryV5Address(ctx, cfg)
 	setBootstrapNodes(ctx, cfg)
 	setBootstrapNodesV5(ctx, cfg)
 
@@ -829,7 +820,6 @@ func SetP2PConfig(ctx *cli.Context, cfg *p2p.Config) {
 		// --dev mode can't use p2p networking.
 		cfg.MaxPeers = 0
 		cfg.ListenAddr = ":0"
-		cfg.DiscoveryV5Addr = ":0"
 		cfg.NoDiscovery = true
 		cfg.DiscoveryV5 = false
 	}

les/backend.go

@@ -221,9 +221,8 @@ func (s *LightEthereum) Start(srvr *p2p.Server) error {
 	s.startBloomHandlers()
 	log.Warn("Light client mode is an experimental feature")
 	s.netRPCService = ethapi.NewPublicNetAPI(srvr, s.networkId)
-	// search the topic belonging to the oldest supported protocol because
-	// servers always advertise all supported protocols
-	protocolVersion := ClientProtocolVersions[len(ClientProtocolVersions)-1]
+	// clients are searching for the first advertised protocol in the list
+	protocolVersion := AdvertiseProtocolVersions[0]
 	s.serverPool.start(srvr, lesTopic(s.blockchain.Genesis().Hash(), protocolVersion))
 	s.protocolManager.Start()
 	return nil

les/protocol.go

@@ -41,8 +41,9 @@ const (
 
 // Supported versions of the les protocol (first is primary)
 var (
-	ClientProtocolVersions = []uint{lpv2, lpv1}
-	ServerProtocolVersions = []uint{lpv2, lpv1}
+	ClientProtocolVersions    = []uint{lpv2, lpv1}
+	ServerProtocolVersions    = []uint{lpv2, lpv1}
+	AdvertiseProtocolVersions = []uint{lpv2} // clients are searching for the first advertised protocol in the list
 )
 
 // Number of implemented message corresponding to different protocol versions.

les/server.go

@@ -56,8 +56,8 @@ func NewLesServer(eth *eth.Ethereum, config *eth.Config) (*LesServer, error) {
 		return nil, err
 	}
 
-	lesTopics := make([]discv5.Topic, len(ServerProtocolVersions))
-	for i, pv := range ServerProtocolVersions {
+	lesTopics := make([]discv5.Topic, len(AdvertiseProtocolVersions))
+	for i, pv := range AdvertiseProtocolVersions {
 		lesTopics[i] = lesTopic(eth.BlockChain().Genesis().Hash(), pv)
 	}
 

mobile/geth.go

@@ -116,7 +116,6 @@ func NewNode(datadir string, config *NodeConfig) (stack *Node, _ error) {
 		P2P: p2p.Config{
 			NoDiscovery:      true,
 			DiscoveryV5:      true,
-			DiscoveryV5Addr:  ":0",
 			BootstrapNodesV5: config.BootstrapNodes.nodes,
 			ListenAddr:       ":0",
 			NAT:              nat.Any(),

node/defaults.go

@@ -41,10 +41,9 @@ var DefaultConfig = Config{
 	WSPort:      DefaultWSPort,
 	WSModules:   []string{"net", "web3"},
 	P2P: p2p.Config{
-		ListenAddr:      ":30303",
-		DiscoveryV5Addr: ":30304",
-		MaxPeers:        25,
-		NAT:             nat.Any(),
+		ListenAddr: ":30303",
+		MaxPeers:   25,
+		NAT:        nat.Any(),
 	},
 }
 

p2p/discover/udp.go

@@ -210,25 +210,23 @@ type reply struct {
 	matched chan<- bool
 }
 
+// ReadPacket is sent to the unhandled channel when it could not be processed
+type ReadPacket struct {
+	Data []byte
+	Addr *net.UDPAddr
+}
+
 // ListenUDP returns a new table that listens for UDP packets on laddr.
-func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, error) {
-	addr, err := net.ResolveUDPAddr("udp", laddr)
-	if err != nil {
-		return nil, err
-	}
-	conn, err := net.ListenUDP("udp", addr)
-	if err != nil {
-		return nil, err
-	}
-	tab, _, err := newUDP(priv, conn, natm, nodeDBPath, netrestrict)
+func ListenUDP(priv *ecdsa.PrivateKey, conn conn, realaddr *net.UDPAddr, unhandled chan ReadPacket, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, error) {
+	tab, _, err := newUDP(priv, conn, realaddr, unhandled, nodeDBPath, netrestrict)
 	if err != nil {
 		return nil, err
 	}
 	log.Info("UDP listener up", "self", tab.self)
 	return tab, nil
 }
 
-func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, *udp, error) {
+func newUDP(priv *ecdsa.PrivateKey, c conn, realaddr *net.UDPAddr, unhandled chan ReadPacket, nodeDBPath string, netrestrict *netutil.Netlist) (*Table, *udp, error) {
 	udp := &udp{
 		conn:        c,
 		priv:        priv,
@@ -237,16 +235,6 @@ func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath strin
 		gotreply:    make(chan reply),
 		addpending:  make(chan *pending),
 	}
-	realaddr := c.LocalAddr().(*net.UDPAddr)
-	if natm != nil {
-		if !realaddr.IP.IsLoopback() {
-			go nat.Map(natm, udp.closing, "udp", realaddr.Port, realaddr.Port, "ethereum discovery")
-		}
-		// TODO: react to external IP changes over time.
-		if ext, err := natm.ExternalIP(); err == nil {
-			realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
-		}
-	}
 	// TODO: separate TCP port
 	udp.ourEndpoint = makeEndpoint(realaddr, uint16(realaddr.Port))
 	tab, err := newTable(udp, PubkeyID(&priv.PublicKey), realaddr, nodeDBPath)
@@ -256,7 +244,7 @@ func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath strin
 	udp.Table = tab
 
 	go udp.loop()
-	go udp.readLoop()
+	go udp.readLoop(unhandled)
 	return udp.Table, udp, nil
 }
 
@@ -492,8 +480,11 @@ func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) ([]byte,
 }
 
 // readLoop runs in its own goroutine. it handles incoming UDP packets.
-func (t *udp) readLoop() {
+func (t *udp) readLoop(unhandled chan ReadPacket) {
 	defer t.conn.Close()
+	if unhandled != nil {
+		defer close(unhandled)
+	}
 	// Discovery packets are defined to be no larger than 1280 bytes.
 	// Packets larger than this size will be cut at the end and treated
 	// as invalid because their hash won't match.
@@ -509,7 +500,12 @@ func (t *udp) readLoop() {
 			log.Debug("UDP read error", "err", err)
 			return
 		}
-		t.handlePacket(from, buf[:nbytes])
+		if t.handlePacket(from, buf[:nbytes]) != nil && unhandled != nil {
+			select {
+			case unhandled <- ReadPacket{buf[:nbytes], from}:
+			default:
+			}
+		}
 	}
 }
 

p2p/discover/udp_test.go

@@ -70,7 +70,8 @@ func newUDPTest(t *testing.T) *udpTest {
 		remotekey:  newkey(),
 		remoteaddr: &net.UDPAddr{IP: net.IP{10, 0, 1, 99}, Port: 30303},
 	}
-	test.table, test.udp, _ = newUDP(test.localkey, test.pipe, nil, "", nil)
+	realaddr := test.pipe.LocalAddr().(*net.UDPAddr)
+	test.table, test.udp, _ = newUDP(test.localkey, test.pipe, realaddr, nil, "", nil)
 	return test
 }
 

p2p/discv5/net.go

@@ -29,7 +29,6 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/crypto/sha3"
 	"github.com/ethereum/go-ethereum/log"
-	"github.com/ethereum/go-ethereum/p2p/nat"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
 	"github.com/ethereum/go-ethereum/rlp"
 )
@@ -141,7 +140,7 @@ type timeoutEvent struct {
 	node *Node
 }
 
-func newNetwork(conn transport, ourPubkey ecdsa.PublicKey, natm nat.Interface, dbPath string, netrestrict *netutil.Netlist) (*Network, error) {
+func newNetwork(conn transport, ourPubkey ecdsa.PublicKey, dbPath string, netrestrict *netutil.Netlist) (*Network, error) {
 	ourID := PubkeyID(&ourPubkey)
 
 	var db *nodeDB

p2p/discv5/net_test.go

@@ -28,7 +28,7 @@ import (
 
 func TestNetwork_Lookup(t *testing.T) {
 	key, _ := crypto.GenerateKey()
-	network, err := newNetwork(lookupTestnet, key.PublicKey, nil, "", nil)
+	network, err := newNetwork(lookupTestnet, key.PublicKey, "", nil)
 	if err != nil {
 		t.Fatal(err)
 	}

p2p/discv5/sim_test.go

@@ -282,7 +282,7 @@ func (s *simulation) launchNode(log bool) *Network {
 	addr := &net.UDPAddr{IP: ip, Port: 30303}
 
 	transport := &simTransport{joinTime: time.Now(), sender: id, senderAddr: addr, sim: s, priv: key}
-	net, err := newNetwork(transport, key.PublicKey, nil, "<no database>", nil)
+	net, err := newNetwork(transport, key.PublicKey, "<no database>", nil)
 	if err != nil {
 		panic("cannot launch new node: " + err.Error())
 	}

p2p/discv5/ticket.go

@@ -643,7 +643,7 @@ func (s *ticketStore) gotTopicNodes(from *Node, hash common.Hash, nodes []rpcNod
 		if ip.IsUnspecified() || ip.IsLoopback() {
 			ip = from.IP
 		}
-		n := NewNode(node.ID, ip, node.UDP-1, node.TCP-1) // subtract one from port while discv5 is running in test mode on UDPport+1
+		n := NewNode(node.ID, ip, node.UDP, node.TCP)
 		select {
 		case chn <- n:
 		default:

p2p/discv5/udp.go

@@ -37,7 +37,7 @@ const Version = 4
 // Errors
 var (
 	errPacketTooSmall   = errors.New("too small")
-	errBadHash          = errors.New("bad hash")
+	errBadPrefix        = errors.New("bad prefix")
 	errExpired          = errors.New("expired")
 	errUnsolicitedReply = errors.New("unsolicited reply")
 	errUnknownNode      = errors.New("unknown node")
@@ -145,10 +145,11 @@ type (
 	}
 )
 
-const (
-	macSize  = 256 / 8
-	sigSize  = 520 / 8
-	headSize = macSize + sigSize // space of packet frame data
+var (
+	versionPrefix     = []byte("temporary discovery v5")
+	versionPrefixSize = len(versionPrefix)
+	sigSize           = 520 / 8
+	headSize          = versionPrefixSize + sigSize // space of packet frame data
 )
 
 // Neighbors replies are sent across multiple packets to
@@ -237,12 +238,12 @@ type udp struct {
 }
 
 // ListenUDP returns a new table that listens for UDP packets on laddr.
-func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBPath string, netrestrict *netutil.Netlist) (*Network, error) {
-	transport, err := listenUDP(priv, laddr)
+func ListenUDP(priv *ecdsa.PrivateKey, conn conn, realaddr *net.UDPAddr, nodeDBPath string, netrestrict *netutil.Netlist) (*Network, error) {
+	transport, err := listenUDP(priv, conn, realaddr)
 	if err != nil {
 		return nil, err
 	}
-	net, err := newNetwork(transport, priv.PublicKey, natm, nodeDBPath, netrestrict)
+	net, err := newNetwork(transport, priv.PublicKey, nodeDBPath, netrestrict)
 	if err != nil {
 		return nil, err
 	}
@@ -251,16 +252,8 @@ func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, nodeDBP
 	return net, nil
 }
 
-func listenUDP(priv *ecdsa.PrivateKey, laddr string) (*udp, error) {
-	addr, err := net.ResolveUDPAddr("udp", laddr)
-	if err != nil {
-		return nil, err
-	}
-	conn, err := net.ListenUDP("udp", addr)
-	if err != nil {
-		return nil, err
-	}
-	return &udp{conn: conn, priv: priv, ourEndpoint: makeEndpoint(addr, uint16(addr.Port))}, nil
+func listenUDP(priv *ecdsa.PrivateKey, conn conn, realaddr *net.UDPAddr) (*udp, error) {
+	return &udp{conn: conn, priv: priv, ourEndpoint: makeEndpoint(realaddr, uint16(realaddr.Port))}, nil
 }
 
 func (t *udp) localAddr() *net.UDPAddr {
@@ -372,11 +365,9 @@ func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) (p, hash
 		log.Error(fmt.Sprint("could not sign packet:", err))
 		return nil, nil, err
 	}
-	copy(packet[macSize:], sig)
-	// add the hash to the front. Note: this doesn't protect the
-	// packet in any way.
-	hash = crypto.Keccak256(packet[macSize:])
-	copy(packet, hash)
+	copy(packet, versionPrefix)
+	copy(packet[versionPrefixSize:], sig)
+	hash = crypto.Keccak256(packet[versionPrefixSize:])
 	return packet, hash, nil
 }
 
@@ -420,17 +411,16 @@ func decodePacket(buffer []byte, pkt *ingressPacket) error {
 	}
 	buf := make([]byte, len(buffer))
 	copy(buf, buffer)
-	hash, sig, sigdata := buf[:macSize], buf[macSize:headSize], buf[headSize:]
-	shouldhash := crypto.Keccak256(buf[macSize:])
-	if !bytes.Equal(hash, shouldhash) {
-		return errBadHash
+	prefix, sig, sigdata := buf[:versionPrefixSize], buf[versionPrefixSize:headSize], buf[headSize:]
+	if !bytes.Equal(prefix, versionPrefix) {
+		return errBadPrefix
 	}
 	fromID, err := recoverNodeID(crypto.Keccak256(buf[headSize:]), sig)
 	if err != nil {
 		return err
 	}
 	pkt.rawData = buf
-	pkt.hash = hash
+	pkt.hash = crypto.Keccak256(buf[versionPrefixSize:])
 	pkt.remoteID = fromID
 	switch pkt.ev = nodeEvent(sigdata[0]); pkt.ev {
 	case pingPacket: