mirror of https://github.com/status-im/op-geth.git
331 lines
8.0 KiB
Go
331 lines
8.0 KiB
Go
package discover
|
|
|
|
import (
|
|
"crypto/ecdsa"
|
|
"crypto/elliptic"
|
|
"encoding/hex"
|
|
"errors"
|
|
"fmt"
|
|
"io"
|
|
"math/big"
|
|
"math/rand"
|
|
"net"
|
|
"net/url"
|
|
"strconv"
|
|
"strings"
|
|
"sync"
|
|
|
|
"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
|
|
}
|
|
|
|
func newNode(id NodeID, addr *net.UDPAddr) *Node {
|
|
return &Node{
|
|
ID: id,
|
|
IP: addr.IP,
|
|
DiscPort: addr.Port,
|
|
TCPPort: addr.Port,
|
|
}
|
|
}
|
|
|
|
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}
|
|
}
|
|
|
|
// 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}
|
|
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)
|
|
}
|
|
return u.String()
|
|
}
|
|
|
|
// ParseNode parses a node URL.
|
|
//
|
|
// A node URL has scheme "enode".
|
|
//
|
|
// The hexadecimal node ID is encoded in the username portion of the
|
|
// URL, separated from the host by an @ sign. The hostname can only be
|
|
// given as an IP address, DNS domain names are not allowed. The port
|
|
// in the host name section is the TCP listening port. If the TCP and
|
|
// UDP (discovery) ports differ, the UDP port is specified as query
|
|
// parameter "discport".
|
|
//
|
|
// In the following example, the node URL describes
|
|
// a node with IP address 10.3.58.6, TCP listening port 30303
|
|
// and UDP discovery port 30301.
|
|
//
|
|
// enode://<hex node id>@10.3.58.6:30303?discport=30301
|
|
func ParseNode(rawurl string) (*Node, error) {
|
|
var n Node
|
|
u, err := url.Parse(rawurl)
|
|
if u.Scheme != "enode" {
|
|
return nil, errors.New("invalid URL scheme, want \"enode\"")
|
|
}
|
|
if u.User == nil {
|
|
return nil, errors.New("does not contain node ID")
|
|
}
|
|
if n.ID, err = HexID(u.User.String()); err != nil {
|
|
return nil, fmt.Errorf("invalid node ID (%v)", err)
|
|
}
|
|
ip, port, err := net.SplitHostPort(u.Host)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("invalid host: %v", err)
|
|
}
|
|
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 {
|
|
return nil, errors.New("invalid port")
|
|
}
|
|
qv := u.Query()
|
|
if qv.Get("discport") == "" {
|
|
n.DiscPort = n.TCPPort
|
|
} else {
|
|
if n.DiscPort, err = strconv.Atoi(qv.Get("discport")); err != nil {
|
|
return nil, errors.New("invalid discport in query")
|
|
}
|
|
}
|
|
return &n, nil
|
|
}
|
|
|
|
// MustParseNode parses a node URL. It panics if the URL is not valid.
|
|
func MustParseNode(rawurl string) *Node {
|
|
n, err := ParseNode(rawurl)
|
|
if err != nil {
|
|
panic("invalid node URL: " + err.Error())
|
|
}
|
|
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
|
|
|
|
// NodeID prints as a long hexadecimal number.
|
|
func (n NodeID) String() string {
|
|
return fmt.Sprintf("%x", n[:])
|
|
}
|
|
|
|
// The Go syntax representation of a NodeID is a call to HexID.
|
|
func (n NodeID) GoString() string {
|
|
return fmt.Sprintf("discover.HexID(\"%x\")", n[:])
|
|
}
|
|
|
|
// HexID converts a hex string to a NodeID.
|
|
// The string may be prefixed with 0x.
|
|
func HexID(in string) (NodeID, error) {
|
|
if strings.HasPrefix(in, "0x") {
|
|
in = in[2:]
|
|
}
|
|
var id NodeID
|
|
b, err := hex.DecodeString(in)
|
|
if err != nil {
|
|
return id, err
|
|
} else if len(b) != len(id) {
|
|
return id, fmt.Errorf("wrong length, need %d hex bytes", len(id))
|
|
}
|
|
copy(id[:], b)
|
|
return id, nil
|
|
}
|
|
|
|
// MustHexID converts a hex string to a NodeID.
|
|
// It panics if the string is not a valid NodeID.
|
|
func MustHexID(in string) NodeID {
|
|
id, err := HexID(in)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return id
|
|
}
|
|
|
|
// PubkeyID returns a marshaled representation of the given public key.
|
|
func PubkeyID(pub *ecdsa.PublicKey) NodeID {
|
|
var id NodeID
|
|
pbytes := elliptic.Marshal(pub.Curve, pub.X, pub.Y)
|
|
if len(pbytes)-1 != len(id) {
|
|
panic(fmt.Errorf("need %d bit pubkey, got %d bits", (len(id)+1)*8, len(pbytes)))
|
|
}
|
|
copy(id[:], pbytes[1:])
|
|
return id
|
|
}
|
|
|
|
// Pubkey returns the public key represented by the node ID.
|
|
// It returns an error if the ID is not a point on the curve.
|
|
func (id NodeID) Pubkey() (*ecdsa.PublicKey, error) {
|
|
p := &ecdsa.PublicKey{Curve: crypto.S256(), X: new(big.Int), Y: new(big.Int)}
|
|
half := len(id) / 2
|
|
p.X.SetBytes(id[:half])
|
|
p.Y.SetBytes(id[half:])
|
|
if !p.Curve.IsOnCurve(p.X, p.Y) {
|
|
return nil, errors.New("not a point on the S256 curve")
|
|
}
|
|
return p, nil
|
|
}
|
|
|
|
// recoverNodeID computes the public key used to sign the
|
|
// given hash from the signature.
|
|
func recoverNodeID(hash, sig []byte) (id NodeID, err error) {
|
|
pubkey, err := secp256k1.RecoverPubkey(hash, sig)
|
|
if err != nil {
|
|
return id, err
|
|
}
|
|
if len(pubkey)-1 != len(id) {
|
|
return id, fmt.Errorf("recovered pubkey has %d bits, want %d bits", len(pubkey)*8, (len(id)+1)*8)
|
|
}
|
|
for i := range id {
|
|
id[i] = pubkey[i+1]
|
|
}
|
|
return id, nil
|
|
}
|
|
|
|
// distcmp compares the distances a->target and b->target.
|
|
// Returns -1 if a is closer to target, 1 if b is closer to target
|
|
// and 0 if they are equal.
|
|
func distcmp(target, a, b NodeID) int {
|
|
for i := range target {
|
|
da := a[i] ^ target[i]
|
|
db := b[i] ^ target[i]
|
|
if da > db {
|
|
return 1
|
|
} else if da < db {
|
|
return -1
|
|
}
|
|
}
|
|
return 0
|
|
}
|
|
|
|
// table of leading zero counts for bytes [0..255]
|
|
var lzcount = [256]int{
|
|
8, 7, 6, 6, 5, 5, 5, 5,
|
|
4, 4, 4, 4, 4, 4, 4, 4,
|
|
3, 3, 3, 3, 3, 3, 3, 3,
|
|
3, 3, 3, 3, 3, 3, 3, 3,
|
|
2, 2, 2, 2, 2, 2, 2, 2,
|
|
2, 2, 2, 2, 2, 2, 2, 2,
|
|
2, 2, 2, 2, 2, 2, 2, 2,
|
|
2, 2, 2, 2, 2, 2, 2, 2,
|
|
1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1,
|
|
1, 1, 1, 1, 1, 1, 1, 1,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
0, 0, 0, 0, 0, 0, 0, 0,
|
|
}
|
|
|
|
// logdist returns the logarithmic distance between a and b, log2(a ^ b).
|
|
func logdist(a, b NodeID) int {
|
|
lz := 0
|
|
for i := range a {
|
|
x := a[i] ^ b[i]
|
|
if x == 0 {
|
|
lz += 8
|
|
} else {
|
|
lz += lzcount[x]
|
|
break
|
|
}
|
|
}
|
|
return len(a)*8 - lz
|
|
}
|
|
|
|
// randomID returns a random NodeID such that logdist(a, b) == n
|
|
func randomID(a NodeID, n int) (b NodeID) {
|
|
if n == 0 {
|
|
return a
|
|
}
|
|
// flip bit at position n, fill the rest with random bits
|
|
b = a
|
|
pos := len(a) - n/8 - 1
|
|
bit := byte(0x01) << (byte(n%8) - 1)
|
|
if bit == 0 {
|
|
pos++
|
|
bit = 0x80
|
|
}
|
|
b[pos] = a[pos]&^bit | ^a[pos]&bit // TODO: randomize end bits
|
|
for i := pos + 1; i < len(a); i++ {
|
|
b[i] = byte(rand.Intn(255))
|
|
}
|
|
return b
|
|
}
|
|
|
|
// nodeDB stores all nodes we know about.
|
|
type nodeDB struct {
|
|
mu sync.RWMutex
|
|
byID map[NodeID]*Node
|
|
}
|
|
|
|
func (db *nodeDB) get(id NodeID) *Node {
|
|
db.mu.RLock()
|
|
defer db.mu.RUnlock()
|
|
return db.byID[id]
|
|
}
|
|
|
|
func (db *nodeDB) add(id NodeID, addr *net.UDPAddr, tcpPort uint16) *Node {
|
|
db.mu.Lock()
|
|
defer db.mu.Unlock()
|
|
if db.byID == nil {
|
|
db.byID = make(map[NodeID]*Node)
|
|
}
|
|
n := &Node{ID: id, IP: addr.IP, DiscPort: addr.Port, TCPPort: int(tcpPort)}
|
|
db.byID[n.ID] = n
|
|
return n
|
|
}
|