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p2p/discover: new endpoint format
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This commit changes the discovery protocol to use the new "v3" endpoint
format, which allows for separate UDP and TCP ports and makes it
possible to discover the UDP address after NAT.
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@fjl
fjl committed Apr 22, 2015
1 parent 2f4cc72 commit 7a804c0
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Showing 10 changed files with 150 additions and 116 deletions.
4 changes: 2 additions & 2 deletions eth/backend.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -269,8 +269,8 @@ func (s *Ethereum) NodeInfo() *NodeInfo {
NodeUrl: node.String(),
NodeID: node.ID.String(),
IP: node.IP.String(),
DiscPort: node.DiscPort,
TCPPort: node.TCPPort,
DiscPort: int(node.UDP),
TCPPort: int(node.TCP),
ListenAddr: s.net.ListenAddr,
Td: s.ChainManager().Td().String(),
}
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63 changes: 23 additions & 40 deletions p2p/discover/node.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,6 @@ import (
"encoding/hex"
"errors"
"fmt"
"io"
"math/big"
"math/rand"
"net"
Expand All @@ -17,49 +16,45 @@ import (

"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
"github.com/ethereum/go-ethereum/rlp"
)

const nodeIDBits = 512

// Node represents a host on the network.
type Node struct {
ID NodeID
IP net.IP

DiscPort int // UDP listening port for discovery protocol
TCPPort int // TCP listening port for RLPx
IP net.IP // len 4 for IPv4 or 16 for IPv6
UDP, TCP uint16 // port numbers
ID NodeID
}

func newNode(id NodeID, addr *net.UDPAddr) *Node {
ip := addr.IP.To4()
if ip == nil {
ip = addr.IP.To16()
}
return &Node{
ID: id,
IP: addr.IP,
DiscPort: addr.Port,
TCPPort: addr.Port,
IP: ip,
UDP: uint16(addr.Port),
TCP: uint16(addr.Port),
ID: id,
}
}

func (n *Node) isValid() bool {
// TODO: don't accept localhost, LAN addresses from internet hosts
return !n.IP.IsMulticast() && !n.IP.IsUnspecified() && n.TCPPort != 0 && n.DiscPort != 0
}

func (n *Node) addr() *net.UDPAddr {
return &net.UDPAddr{IP: n.IP, Port: n.DiscPort}
return &net.UDPAddr{IP: n.IP, Port: int(n.UDP)}
}

// The string representation of a Node is a URL.
// Please see ParseNode for a description of the format.
func (n *Node) String() string {
addr := net.TCPAddr{IP: n.IP, Port: n.TCPPort}
addr := net.TCPAddr{IP: n.IP, Port: int(n.TCP)}
u := url.URL{
Scheme: "enode",
User: url.User(fmt.Sprintf("%x", n.ID[:])),
Host: addr.String(),
}
if n.DiscPort != n.TCPPort {
u.RawQuery = "discport=" + strconv.Itoa(n.DiscPort)
if n.UDP != n.TCP {
u.RawQuery = "discport=" + strconv.Itoa(int(n.UDP))
}
return u.String()
}
Expand Down Expand Up @@ -99,16 +94,20 @@ func ParseNode(rawurl string) (*Node, error) {
if n.IP = net.ParseIP(ip); n.IP == nil {
return nil, errors.New("invalid IP address")
}
if n.TCPPort, err = strconv.Atoi(port); err != nil {
tcp, err := strconv.ParseUint(port, 10, 16)
if err != nil {
return nil, errors.New("invalid port")
}
n.TCP = uint16(tcp)
qv := u.Query()
if qv.Get("discport") == "" {
n.DiscPort = n.TCPPort
n.UDP = n.TCP
} else {
if n.DiscPort, err = strconv.Atoi(qv.Get("discport")); err != nil {
udp, err := strconv.ParseUint(qv.Get("discport"), 10, 16)
if err != nil {
return nil, errors.New("invalid discport in query")
}
n.UDP = uint16(udp)
}
return &n, nil
}
Expand All @@ -122,22 +121,6 @@ func MustParseNode(rawurl string) *Node {
return n
}

func (n Node) EncodeRLP(w io.Writer) error {
return rlp.Encode(w, rpcNode{IP: n.IP.String(), Port: uint16(n.TCPPort), ID: n.ID})
}
func (n *Node) DecodeRLP(s *rlp.Stream) (err error) {
var ext rpcNode
if err = s.Decode(&ext); err == nil {
n.TCPPort = int(ext.Port)
n.DiscPort = int(ext.Port)
n.ID = ext.ID
if n.IP = net.ParseIP(ext.IP); n.IP == nil {
return errors.New("invalid IP string")
}
}
return err
}

// NodeID is a unique identifier for each node.
// The node identifier is a marshaled elliptic curve public key.
type NodeID [nodeIDBits / 8]byte
Expand Down Expand Up @@ -324,7 +307,7 @@ func (db *nodeDB) add(id NodeID, addr *net.UDPAddr, tcpPort uint16) *Node {
if db.byID == nil {
db.byID = make(map[NodeID]*Node)
}
n := &Node{ID: id, IP: addr.IP, DiscPort: addr.Port, TCPPort: int(tcpPort)}
n := &Node{ID: id, IP: addr.IP, UDP: uint16(addr.Port), TCP: tcpPort}
db.byID[n.ID] = n
return n
}
26 changes: 13 additions & 13 deletions p2p/discover/node_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -49,28 +49,28 @@ var parseNodeTests = []struct {
{
rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:52150",
wantResult: &Node{
ID: MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
IP: net.ParseIP("127.0.0.1"),
DiscPort: 52150,
TCPPort: 52150,
ID: MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
IP: net.ParseIP("127.0.0.1"),
UDP: 52150,
TCP: 52150,
},
},
{
rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@[::]:52150",
wantResult: &Node{
ID: MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
IP: net.ParseIP("::"),
DiscPort: 52150,
TCPPort: 52150,
ID: MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
IP: net.ParseIP("::"),
UDP: 52150,
TCP: 52150,
},
},
{
rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:52150?discport=223344",
rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:52150?discport=22334",
wantResult: &Node{
ID: MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
IP: net.ParseIP("127.0.0.1"),
DiscPort: 223344,
TCPPort: 52150,
ID: MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
IP: net.ParseIP("127.0.0.1"),
UDP: 22334,
TCP: 52150,
},
},
}
Expand Down
2 changes: 1 addition & 1 deletion p2p/discover/table.go
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Original file line number Diff line number Diff line change
Expand Up @@ -205,7 +205,7 @@ func (tab *Table) bondall(nodes []*Node) (result []*Node) {
rc := make(chan *Node, len(nodes))
for i := range nodes {
go func(n *Node) {
nn, _ := tab.bond(false, n.ID, n.addr(), uint16(n.TCPPort))
nn, _ := tab.bond(false, n.ID, n.addr(), uint16(n.TCP))
rc <- nn
}(nodes[i])
}
Expand Down
4 changes: 2 additions & 2 deletions p2p/discover/table_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -261,9 +261,9 @@ func (t findnodeOracle) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID
panic("query to node at distance 0")
default:
// TODO: add more randomness to distances
next := toaddr.Port - 1
next := uint16(toaddr.Port) - 1
for i := 0; i < bucketSize; i++ {
result = append(result, &Node{ID: randomID(t.target, next), DiscPort: next})
result = append(result, &Node{ID: randomID(t.target, int(next)), UDP: next})
}
}
return result, nil
Expand Down
78 changes: 52 additions & 26 deletions p2p/discover/udp.go
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Original file line number Diff line number Diff line change
Expand Up @@ -49,16 +49,20 @@ const (
// RPC request structures
type (
ping struct {
Version uint // must match Version
IP string // our IP
Port uint16 // our port
Version uint
From, To rpcEndpoint
Expiration uint64
}

// reply to Ping
// pong is the reply to ping.
pong struct {
ReplyTok []byte
Expiration uint64
// This field should mirror the UDP envelope address
// of the ping packet, which provides a way to discover the
// the external address (after NAT).
To rpcEndpoint

ReplyTok []byte // This contains the hash of the ping packet.
Expiration uint64 // Absolute timestamp at which the packet becomes invalid.
}

findnode struct {
Expand All @@ -73,12 +77,25 @@ type (
Nodes []*Node
Expiration uint64
}

rpcEndpoint struct {
IP net.IP // len 4 for IPv4 or 16 for IPv6
UDP uint16 // for discovery protocol
TCP uint16 // for RLPx protocol
}
)

type rpcNode struct {
IP string
Port uint16
ID NodeID
func makeEndpoint(addr *net.UDPAddr, tcpPort uint16) rpcEndpoint {
ip := addr.IP.To4()
if ip == nil {
ip = addr.IP.To16()
}
return rpcEndpoint{IP: ip, UDP: uint16(addr.Port), TCP: tcpPort}
}

func validNode(n *Node) bool {
// TODO: don't accept localhost, LAN addresses from internet hosts
return !n.IP.IsMulticast() && !n.IP.IsUnspecified() && n.UDP != 0
}

type packet interface {
Expand All @@ -94,8 +111,9 @@ type conn interface {

// udp implements the RPC protocol.
type udp struct {
conn conn
priv *ecdsa.PrivateKey
conn conn
priv *ecdsa.PrivateKey
ourEndpoint rpcEndpoint

addpending chan *pending
gotreply chan reply
Expand Down Expand Up @@ -176,6 +194,8 @@ func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface) (*Table, *udp) {
realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
}
}
// TODO: separate TCP port
udp.ourEndpoint = makeEndpoint(realaddr, uint16(realaddr.Port))
udp.Table = newTable(udp, PubkeyID(&priv.PublicKey), realaddr)
go udp.loop()
go udp.readLoop()
Expand All @@ -194,8 +214,8 @@ func (t *udp) ping(toid NodeID, toaddr *net.UDPAddr) error {
errc := t.pending(toid, pongPacket, func(interface{}) bool { return true })
t.send(toaddr, pingPacket, ping{
Version: Version,
IP: t.self.IP.String(),
Port: uint16(t.self.TCPPort),
From: t.ourEndpoint,
To: makeEndpoint(toaddr, 0), // TODO: maybe use known TCP port from DB
Expiration: uint64(time.Now().Add(expiration).Unix()),
})
return <-errc
Expand All @@ -214,7 +234,7 @@ func (t *udp) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node
reply := r.(*neighbors)
for _, n := range reply.Nodes {
nreceived++
if n.isValid() {
if validNode(n) {
nodes = append(nodes, n)
}
}
Expand Down Expand Up @@ -374,17 +394,22 @@ func (t *udp) readLoop() {
if err != nil {
return
}
packet, fromID, hash, err := decodePacket(buf[:nbytes])
if err != nil {
glog.V(logger.Debug).Infof("Bad packet from %v: %v\n", from, err)
continue
}
status := "ok"
if err := packet.handle(t, from, fromID, hash); err != nil {
status = err.Error()
}
glog.V(logger.Detail).Infof("<<< %v %T: %s\n", from, packet, status)
t.handlePacket(from, buf[:nbytes])
}
}

func (t *udp) handlePacket(from *net.UDPAddr, buf []byte) error {
packet, fromID, hash, err := decodePacket(buf)
if err != nil {
glog.V(logger.Debug).Infof("Bad packet from %v: %v\n", from, err)
return err
}
status := "ok"
if err = packet.handle(t, from, fromID, hash); err != nil {
status = err.Error()
}
glog.V(logger.Detail).Infof("<<< %v %T: %s\n", from, packet, status)
return err
}

func decodePacket(buf []byte) (packet, NodeID, []byte, error) {
Expand Down Expand Up @@ -425,12 +450,13 @@ func (req *ping) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte) er
return errBadVersion
}
t.send(from, pongPacket, pong{
To: makeEndpoint(from, req.From.TCP),
ReplyTok: mac,
Expiration: uint64(time.Now().Add(expiration).Unix()),
})
if !t.handleReply(fromID, pingPacket, req) {
// Note: we're ignoring the provided IP address right now
go t.bond(true, fromID, from, req.Port)
go t.bond(true, fromID, from, req.From.TCP)
}
return nil
}
Expand Down
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