b7394d7942
This adds an implementation of the current discovery v5 spec. There is full integration with cmd/devp2p and enode.Iterator in this version. In theory we could enable the new protocol as a replacement of discovery v4 at any time. In practice, there will likely be a few more changes to the spec and implementation before this can happen.
124 lines
3.7 KiB
Go
124 lines
3.7 KiB
Go
// Copyright 2020 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 (
|
|
crand "crypto/rand"
|
|
|
|
"github.com/ethereum/go-ethereum/common/mclock"
|
|
"github.com/ethereum/go-ethereum/p2p/enode"
|
|
"github.com/hashicorp/golang-lru/simplelru"
|
|
)
|
|
|
|
// The sessionCache keeps negotiated encryption keys and
|
|
// state for in-progress handshakes in the Discovery v5 wire protocol.
|
|
type sessionCache struct {
|
|
sessions *simplelru.LRU
|
|
handshakes map[sessionID]*whoareyouV5
|
|
clock mclock.Clock
|
|
}
|
|
|
|
// sessionID identifies a session or handshake.
|
|
type sessionID struct {
|
|
id enode.ID
|
|
addr string
|
|
}
|
|
|
|
// session contains session information
|
|
type session struct {
|
|
writeKey []byte
|
|
readKey []byte
|
|
nonceCounter uint32
|
|
}
|
|
|
|
func newSessionCache(maxItems int, clock mclock.Clock) *sessionCache {
|
|
cache, err := simplelru.NewLRU(maxItems, nil)
|
|
if err != nil {
|
|
panic("can't create session cache")
|
|
}
|
|
return &sessionCache{
|
|
sessions: cache,
|
|
handshakes: make(map[sessionID]*whoareyouV5),
|
|
clock: clock,
|
|
}
|
|
}
|
|
|
|
// nextNonce creates a nonce for encrypting a message to the given session.
|
|
func (sc *sessionCache) nextNonce(id enode.ID, addr string) []byte {
|
|
n := make([]byte, gcmNonceSize)
|
|
crand.Read(n)
|
|
return n
|
|
}
|
|
|
|
// session returns the current session for the given node, if any.
|
|
func (sc *sessionCache) session(id enode.ID, addr string) *session {
|
|
item, ok := sc.sessions.Get(sessionID{id, addr})
|
|
if !ok {
|
|
return nil
|
|
}
|
|
return item.(*session)
|
|
}
|
|
|
|
// readKey returns the current read key for the given node.
|
|
func (sc *sessionCache) readKey(id enode.ID, addr string) []byte {
|
|
if s := sc.session(id, addr); s != nil {
|
|
return s.readKey
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// writeKey returns the current read key for the given node.
|
|
func (sc *sessionCache) writeKey(id enode.ID, addr string) []byte {
|
|
if s := sc.session(id, addr); s != nil {
|
|
return s.writeKey
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// storeNewSession stores new encryption keys in the cache.
|
|
func (sc *sessionCache) storeNewSession(id enode.ID, addr string, r, w []byte) {
|
|
sc.sessions.Add(sessionID{id, addr}, &session{
|
|
readKey: r, writeKey: w,
|
|
})
|
|
}
|
|
|
|
// getHandshake gets the handshake challenge we previously sent to the given remote node.
|
|
func (sc *sessionCache) getHandshake(id enode.ID, addr string) *whoareyouV5 {
|
|
return sc.handshakes[sessionID{id, addr}]
|
|
}
|
|
|
|
// storeSentHandshake stores the handshake challenge sent to the given remote node.
|
|
func (sc *sessionCache) storeSentHandshake(id enode.ID, addr string, challenge *whoareyouV5) {
|
|
challenge.sent = sc.clock.Now()
|
|
sc.handshakes[sessionID{id, addr}] = challenge
|
|
}
|
|
|
|
// deleteHandshake deletes handshake data for the given node.
|
|
func (sc *sessionCache) deleteHandshake(id enode.ID, addr string) {
|
|
delete(sc.handshakes, sessionID{id, addr})
|
|
}
|
|
|
|
// handshakeGC deletes timed-out handshakes.
|
|
func (sc *sessionCache) handshakeGC() {
|
|
deadline := sc.clock.Now().Add(-handshakeTimeout)
|
|
for key, challenge := range sc.handshakes {
|
|
if challenge.sent < deadline {
|
|
delete(sc.handshakes, key)
|
|
}
|
|
}
|
|
}
|