plugeth/eth/protocols/eth/discovery.go
Péter Szilágyi 017831dd5b
core, eth: split eth package, implement snap protocol (#21482)
This commit splits the eth package, separating the handling of eth and snap protocols. It also includes the capability to run snap sync (https://github.com/ethereum/devp2p/blob/master/caps/snap.md) , but does not enable it by default. 

Co-authored-by: Marius van der Wijden <m.vanderwijden@live.de>
Co-authored-by: Martin Holst Swende <martin@swende.se>
2020-12-14 10:27:15 +01:00

66 lines
2.1 KiB
Go

// Copyright 2019 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 eth
import (
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/forkid"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/rlp"
)
// enrEntry is the ENR entry which advertises `eth` protocol on the discovery.
type enrEntry struct {
ForkID forkid.ID // Fork identifier per EIP-2124
// Ignore additional fields (for forward compatibility).
Rest []rlp.RawValue `rlp:"tail"`
}
// ENRKey implements enr.Entry.
func (e enrEntry) ENRKey() string {
return "eth"
}
// StartENRUpdater starts the `eth` ENR updater loop, which listens for chain
// head events and updates the requested node record whenever a fork is passed.
func StartENRUpdater(chain *core.BlockChain, ln *enode.LocalNode) {
var newHead = make(chan core.ChainHeadEvent, 10)
sub := chain.SubscribeChainHeadEvent(newHead)
go func() {
defer sub.Unsubscribe()
for {
select {
case <-newHead:
ln.Set(currentENREntry(chain))
case <-sub.Err():
// Would be nice to sync with Stop, but there is no
// good way to do that.
return
}
}
}()
}
// currentENREntry constructs an `eth` ENR entry based on the current state of the chain.
func currentENREntry(chain *core.BlockChain) *enrEntry {
return &enrEntry{
ForkID: forkid.NewID(chain.Config(), chain.Genesis().Hash(), chain.CurrentHeader().Number.Uint64()),
}
}