// Copyright 2016 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 les
import (
"sync"
)
const dropTimeoutRatio = 20
type odrPeerInfo struct {
reqTimeSum, reqTimeCnt, reqCnt, timeoutCnt uint64
}
// odrPeerSet represents the collection of active peer participating in the block
// download procedure.
type odrPeerSet struct {
peers map[*peer]*odrPeerInfo
lock sync.RWMutex
}
// newPeerSet creates a new peer set top track the active download sources.
func newOdrPeerSet() *odrPeerSet {
return &odrPeerSet{
peers: make(map[*peer]*odrPeerInfo),
}
}
// Register injects a new peer into the working set, or returns an error if the
// peer is already known.
func (ps *odrPeerSet) register(p *peer) error {
ps.lock.Lock()
defer ps.lock.Unlock()
if _, ok := ps.peers[p]; ok {
return errAlreadyRegistered
}
ps.peers[p] = &odrPeerInfo{}
return nil
}
// Unregister removes a remote peer from the active set, disabling any further
// actions to/from that particular entity.
func (ps *odrPeerSet) unregister(p *peer) error {
ps.lock.Lock()
defer ps.lock.Unlock()
if _, ok := ps.peers[p]; !ok {
return errNotRegistered
}
delete(ps.peers, p)
return nil
}
func (ps *odrPeerSet) peerPriority(p *peer, info *odrPeerInfo, req LesOdrRequest) uint64 {
tm := p.fcServer.CanSend(req.GetCost(p))
if info.reqTimeCnt > 0 {
tm += info.reqTimeSum / info.reqTimeCnt
}
return tm
}
func (ps *odrPeerSet) bestPeer(req LesOdrRequest, exclude map[*peer]struct{}) *peer {
var best *peer
var bpv uint64
ps.lock.Lock()
defer ps.lock.Unlock()
for p, info := range ps.peers {
if _, ok := exclude[p]; !ok {
pv := ps.peerPriority(p, info, req)
if best == nil || pv < bpv {
best = p
bpv = pv
}
}
}
return best
}
func (ps *odrPeerSet) updateTimeout(p *peer, timeout bool) (drop bool) {
ps.lock.Lock()
defer ps.lock.Unlock()
if info, ok := ps.peers[p]; ok {
info.reqCnt++
if timeout {
// check ratio before increase to allow an extra timeout
if info.timeoutCnt*dropTimeoutRatio >= info.reqCnt {
return true
}
info.timeoutCnt++
}
}
return false
}
func (ps *odrPeerSet) updateServTime(p *peer, servTime uint64) {
ps.lock.Lock()
defer ps.lock.Unlock()
if info, ok := ps.peers[p]; ok {
info.reqTimeSum += servTime
info.reqTimeCnt++
}
}
