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// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package discover
import (
"crypto/ecdsa"
"errors"
"math/big"
"net"
"time"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
"github.com/ethereum/go-ethereum/p2p/enode"
)
// node represents a host on the network.
// The fields of Node may not be modified.
type node struct {
enode.Node
addedAt time.Time // time when the node was added to the table
livenessChecks uint // how often liveness was checked
}
type encPubkey [64]byte
func encodePubkey(key *ecdsa.PublicKey) encPubkey {
var e encPubkey
math.ReadBits(key.X, e[:len(e)/2])
math.ReadBits(key.Y, e[len(e)/2:])
return e
}
func decodePubkey(e encPubkey) (*ecdsa.PublicKey, error) {
p := &ecdsa.PublicKey{Curve: crypto.S256(), X: new(big.Int), Y: new(big.Int)}
half := len(e) / 2
p.X.SetBytes(e[:half])
p.Y.SetBytes(e[half:])
if !p.Curve.IsOnCurve(p.X, p.Y) {
return nil, errors.New("invalid secp256k1 curve point")
}
return p, nil
}
func (e encPubkey) id() enode.ID {
return enode.ID(crypto.Keccak256Hash(e[:]))
}
// recoverNodeKey computes the public key used to sign the
// given hash from the signature.
func recoverNodeKey(hash, sig []byte) (key encPubkey, err error) {
pubkey, err := secp256k1.RecoverPubkey(hash, sig)
if err != nil {
return key, err
}
copy(key[:], pubkey[1:])
return key, nil
}
func wrapNode(n *enode.Node) *node {
return &node{Node: *n}
}
func wrapNodes(ns []*enode.Node) []*node {
result := make([]*node, len(ns))
for i, n := range ns {
result[i] = wrapNode(n)
}
return result
}
func unwrapNode(n *node) *enode.Node {
return &n.Node
}
func unwrapNodes(ns []*node) []*enode.Node {
result := make([]*enode.Node, len(ns))
for i, n := range ns {
result[i] = unwrapNode(n)
}
return result
}
func (n *node) addr() *net.UDPAddr {
return &net.UDPAddr{IP: n.IP(), Port: n.UDP()}
}
func (n *node) String() string {
return n.Node.String()
}