302 lines
8.7 KiB
Go
302 lines
8.7 KiB
Go
// Copyright 2020 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package eth
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import (
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"errors"
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"math/big"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/eth/protocols/eth"
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"github.com/ethereum/go-ethereum/eth/protocols/snap"
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"github.com/ethereum/go-ethereum/event"
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"github.com/ethereum/go-ethereum/p2p"
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)
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var (
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// errPeerSetClosed is returned if a peer is attempted to be added or removed
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// from the peer set after it has been terminated.
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errPeerSetClosed = errors.New("peerset closed")
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// errPeerAlreadyRegistered is returned if a peer is attempted to be added
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// to the peer set, but one with the same id already exists.
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errPeerAlreadyRegistered = errors.New("peer already registered")
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// errPeerNotRegistered is returned if a peer is attempted to be removed from
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// a peer set, but no peer with the given id exists.
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errPeerNotRegistered = errors.New("peer not registered")
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// ethConnectTimeout is the `snap` timeout for `eth` to connect too.
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ethConnectTimeout = 3 * time.Second
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)
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// peerSet represents the collection of active peers currently participating in
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// the `eth` or `snap` protocols.
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type peerSet struct {
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ethPeers map[string]*ethPeer // Peers connected on the `eth` protocol
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snapPeers map[string]*snapPeer // Peers connected on the `snap` protocol
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ethJoinFeed event.Feed // Events when an `eth` peer successfully joins
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ethDropFeed event.Feed // Events when an `eth` peer gets dropped
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snapJoinFeed event.Feed // Events when a `snap` peer joins on both `eth` and `snap`
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snapDropFeed event.Feed // Events when a `snap` peer gets dropped (only if fully joined)
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scope event.SubscriptionScope // Subscription group to unsubscribe everyone at once
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lock sync.RWMutex
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closed bool
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}
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// newPeerSet creates a new peer set to track the active participants.
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func newPeerSet() *peerSet {
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return &peerSet{
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ethPeers: make(map[string]*ethPeer),
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snapPeers: make(map[string]*snapPeer),
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}
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}
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// subscribeEthJoin registers a subscription for peers joining (and completing
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// the handshake) on the `eth` protocol.
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func (ps *peerSet) subscribeEthJoin(ch chan<- *eth.Peer) event.Subscription {
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return ps.scope.Track(ps.ethJoinFeed.Subscribe(ch))
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}
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// subscribeEthDrop registers a subscription for peers being dropped from the
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// `eth` protocol.
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func (ps *peerSet) subscribeEthDrop(ch chan<- *eth.Peer) event.Subscription {
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return ps.scope.Track(ps.ethDropFeed.Subscribe(ch))
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}
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// subscribeSnapJoin registers a subscription for peers joining (and completing
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// the `eth` join) on the `snap` protocol.
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func (ps *peerSet) subscribeSnapJoin(ch chan<- *snap.Peer) event.Subscription {
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return ps.scope.Track(ps.snapJoinFeed.Subscribe(ch))
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}
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// subscribeSnapDrop registers a subscription for peers being dropped from the
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// `snap` protocol.
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func (ps *peerSet) subscribeSnapDrop(ch chan<- *snap.Peer) event.Subscription {
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return ps.scope.Track(ps.snapDropFeed.Subscribe(ch))
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}
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// registerEthPeer injects a new `eth` peer into the working set, or returns an
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// error if the peer is already known. The peer is announced on the `eth` join
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// feed and if it completes a pending `snap` peer, also on that feed.
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func (ps *peerSet) registerEthPeer(peer *eth.Peer) error {
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ps.lock.Lock()
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if ps.closed {
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ps.lock.Unlock()
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return errPeerSetClosed
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}
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id := peer.ID()
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if _, ok := ps.ethPeers[id]; ok {
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ps.lock.Unlock()
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return errPeerAlreadyRegistered
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}
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ps.ethPeers[id] = ðPeer{Peer: peer}
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snap, ok := ps.snapPeers[id]
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ps.lock.Unlock()
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if ok {
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// Previously dangling `snap` peer, stop it's timer since `eth` connected
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snap.lock.Lock()
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if snap.ethDrop != nil {
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snap.ethDrop.Stop()
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snap.ethDrop = nil
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}
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snap.lock.Unlock()
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}
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ps.ethJoinFeed.Send(peer)
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if ok {
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ps.snapJoinFeed.Send(snap.Peer)
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}
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return nil
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}
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// unregisterEthPeer removes a remote peer from the active set, disabling any further
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// actions to/from that particular entity. The drop is announced on the `eth` drop
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// feed and also on the `snap` feed if the eth/snap duality was broken just now.
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func (ps *peerSet) unregisterEthPeer(id string) error {
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ps.lock.Lock()
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eth, ok := ps.ethPeers[id]
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if !ok {
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ps.lock.Unlock()
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return errPeerNotRegistered
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}
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delete(ps.ethPeers, id)
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snap, ok := ps.snapPeers[id]
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ps.lock.Unlock()
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ps.ethDropFeed.Send(eth)
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if ok {
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ps.snapDropFeed.Send(snap)
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}
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return nil
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}
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// registerSnapPeer injects a new `snap` peer into the working set, or returns
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// an error if the peer is already known. The peer is announced on the `snap`
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// join feed if it completes an existing `eth` peer.
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//
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// If the peer isn't yet connected on `eth` and fails to do so within a given
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// amount of time, it is dropped. This enforces that `snap` is an extension to
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// `eth`, not a standalone leeching protocol.
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func (ps *peerSet) registerSnapPeer(peer *snap.Peer) error {
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ps.lock.Lock()
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if ps.closed {
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ps.lock.Unlock()
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return errPeerSetClosed
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}
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id := peer.ID()
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if _, ok := ps.snapPeers[id]; ok {
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ps.lock.Unlock()
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return errPeerAlreadyRegistered
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}
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ps.snapPeers[id] = &snapPeer{Peer: peer}
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_, ok := ps.ethPeers[id]
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if !ok {
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// Dangling `snap` peer, start a timer to drop if `eth` doesn't connect
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ps.snapPeers[id].ethDrop = time.AfterFunc(ethConnectTimeout, func() {
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peer.Log().Warn("Snapshot peer missing eth, dropping", "addr", peer.RemoteAddr(), "type", peer.Name())
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peer.Disconnect(p2p.DiscUselessPeer)
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})
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}
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ps.lock.Unlock()
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if ok {
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ps.snapJoinFeed.Send(peer)
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}
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return nil
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}
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// unregisterSnapPeer removes a remote peer from the active set, disabling any
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// further actions to/from that particular entity. The drop is announced on the
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// `snap` drop feed.
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func (ps *peerSet) unregisterSnapPeer(id string) error {
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ps.lock.Lock()
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peer, ok := ps.snapPeers[id]
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if !ok {
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ps.lock.Unlock()
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return errPeerNotRegistered
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}
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delete(ps.snapPeers, id)
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ps.lock.Unlock()
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peer.lock.Lock()
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if peer.ethDrop != nil {
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peer.ethDrop.Stop()
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peer.ethDrop = nil
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}
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peer.lock.Unlock()
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ps.snapDropFeed.Send(peer)
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return nil
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}
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// ethPeer retrieves the registered `eth` peer with the given id.
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func (ps *peerSet) ethPeer(id string) *ethPeer {
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ps.lock.RLock()
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defer ps.lock.RUnlock()
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return ps.ethPeers[id]
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}
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// snapPeer retrieves the registered `snap` peer with the given id.
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func (ps *peerSet) snapPeer(id string) *snapPeer {
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ps.lock.RLock()
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defer ps.lock.RUnlock()
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return ps.snapPeers[id]
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}
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// ethPeersWithoutBlock retrieves a list of `eth` peers that do not have a given
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// block in their set of known hashes so it might be propagated to them.
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func (ps *peerSet) ethPeersWithoutBlock(hash common.Hash) []*ethPeer {
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ps.lock.RLock()
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defer ps.lock.RUnlock()
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list := make([]*ethPeer, 0, len(ps.ethPeers))
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for _, p := range ps.ethPeers {
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if !p.KnownBlock(hash) {
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list = append(list, p)
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}
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}
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return list
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}
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// ethPeersWithoutTransaction retrieves a list of `eth` peers that do not have a
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// given transaction in their set of known hashes.
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func (ps *peerSet) ethPeersWithoutTransaction(hash common.Hash) []*ethPeer {
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ps.lock.RLock()
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defer ps.lock.RUnlock()
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list := make([]*ethPeer, 0, len(ps.ethPeers))
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for _, p := range ps.ethPeers {
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if !p.KnownTransaction(hash) {
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list = append(list, p)
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}
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}
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return list
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}
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// Len returns if the current number of `eth` peers in the set. Since the `snap`
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// peers are tied to the existnce of an `eth` connection, that will always be a
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// subset of `eth`.
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func (ps *peerSet) Len() int {
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ps.lock.RLock()
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defer ps.lock.RUnlock()
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return len(ps.ethPeers)
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}
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// ethPeerWithHighestTD retrieves the known peer with the currently highest total
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// difficulty.
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func (ps *peerSet) ethPeerWithHighestTD() *eth.Peer {
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ps.lock.RLock()
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defer ps.lock.RUnlock()
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var (
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bestPeer *eth.Peer
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bestTd *big.Int
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)
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for _, p := range ps.ethPeers {
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if _, td := p.Head(); bestPeer == nil || td.Cmp(bestTd) > 0 {
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bestPeer, bestTd = p.Peer, td
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}
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}
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return bestPeer
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}
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// close disconnects all peers.
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func (ps *peerSet) close() {
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ps.lock.Lock()
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defer ps.lock.Unlock()
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for _, p := range ps.ethPeers {
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p.Disconnect(p2p.DiscQuitting)
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}
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for _, p := range ps.snapPeers {
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p.Disconnect(p2p.DiscQuitting)
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}
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ps.closed = true
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}
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