75 lines
2.3 KiB
Go
75 lines
2.3 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/dnsdisc"
|
|
"github.com/ethereum/go-ethereum/p2p/enode"
|
|
"github.com/ethereum/go-ethereum/rlp"
|
|
)
|
|
|
|
// ethEntry is the "eth" ENR entry which advertises eth protocol
|
|
// on the discovery network.
|
|
type ethEntry 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 ethEntry) ENRKey() string {
|
|
return "eth"
|
|
}
|
|
|
|
// startEthEntryUpdate starts the ENR updater loop.
|
|
func (eth *Ethereum) startEthEntryUpdate(ln *enode.LocalNode) {
|
|
var newHead = make(chan core.ChainHeadEvent, 10)
|
|
sub := eth.blockchain.SubscribeChainHeadEvent(newHead)
|
|
|
|
go func() {
|
|
defer sub.Unsubscribe()
|
|
for {
|
|
select {
|
|
case <-newHead:
|
|
ln.Set(eth.currentEthEntry())
|
|
case <-sub.Err():
|
|
// Would be nice to sync with eth.Stop, but there is no
|
|
// good way to do that.
|
|
return
|
|
}
|
|
}
|
|
}()
|
|
}
|
|
|
|
func (eth *Ethereum) currentEthEntry() *ethEntry {
|
|
return ðEntry{ForkID: forkid.NewID(eth.blockchain.Config(), eth.blockchain.Genesis().Hash(),
|
|
eth.blockchain.CurrentHeader().Number.Uint64())}
|
|
}
|
|
|
|
// setupDiscovery creates the node discovery source for the `eth` and `snap`
|
|
// protocols.
|
|
func setupDiscovery(urls []string) (enode.Iterator, error) {
|
|
if len(urls) == 0 {
|
|
return nil, nil
|
|
}
|
|
client := dnsdisc.NewClient(dnsdisc.Config{})
|
|
return client.NewIterator(urls...)
|
|
}
|