p2p: improve peer selection logic
This commit introduces a new (temporary) peer selection strategy based on random lookups. While we're here, also implement the TODOs in dialLoop.
This commit is contained in:
Felix Lange
parent
7be05b4b9d
commit
22d1f0faf1
117
p2p/server.go
117
p2p/server.go
@ -3,6 +3,7 @@ package p2p
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import (
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"bytes"
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"crypto/ecdsa"
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"crypto/rand"
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"errors"
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"fmt"
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"net"
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@ -276,46 +277,58 @@ func (srv *Server) listenLoop() {
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}
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func (srv *Server) dialLoop() {
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var (
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dialed = make(chan *discover.Node)
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dialing = make(map[discover.NodeID]bool)
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findresults = make(chan []*discover.Node)
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refresh = time.NewTimer(0)
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)
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defer srv.loopWG.Done()
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refresh := time.NewTicker(refreshPeersInterval)
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defer refresh.Stop()
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// TODO: maybe limit number of active dials
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dial := func(dest *discover.Node) {
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srv.lock.Lock()
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ok, _ := srv.checkPeer(dest.ID)
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srv.lock.Unlock()
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// Don't dial nodes that would fail the checks in addPeer.
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// This is important because the connection handshake is a lot
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// of work and we'd rather avoid doing that work for peers
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// that can't be added.
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if !ok || dialing[dest.ID] {
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return
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}
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dialing[dest.ID] = true
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srv.peerWG.Add(1)
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go func() {
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srv.dialNode(dest)
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dialed <- dest
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}()
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}
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srv.ntab.Bootstrap(srv.BootstrapNodes)
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go srv.findPeers()
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dialed := make(chan *discover.Node)
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dialing := make(map[discover.NodeID]bool)
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// TODO: limit number of active dials
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// TODO: ensure only one findPeers goroutine is running
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// TODO: pause findPeers when we're at capacity
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for {
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select {
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case <-refresh.C:
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go srv.findPeers()
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case dest := <-srv.peerConnect:
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// avoid dialing nodes that are already connected.
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// there is another check for this in addPeer,
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// which runs after the handshake.
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srv.lock.Lock()
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_, isconnected := srv.peers[dest.ID]
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needpeers := len(srv.peers) < srv.MaxPeers
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srv.lock.Unlock()
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if isconnected || dialing[dest.ID] || dest.ID == srv.Self().ID {
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continue
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if needpeers {
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go func() {
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var target discover.NodeID
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rand.Read(target[:])
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findresults <- srv.ntab.Lookup(target)
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}()
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refresh.Stop()
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}
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dialing[dest.ID] = true
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srv.peerWG.Add(1)
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go func() {
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srv.dialNode(dest)
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// at this point, the peer has been added
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// or discarded. either way, we're not dialing it anymore.
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dialed <- dest
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}()
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case dest := <-srv.peerConnect:
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dial(dest)
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case dests := <-findresults:
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for _, dest := range dests {
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dial(dest)
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}
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refresh.Reset(refreshPeersInterval)
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case dest := <-dialed:
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delete(dialing, dest.ID)
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@ -341,24 +354,6 @@ func (srv *Server) Self() *discover.Node {
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return srv.ntab.Self()
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}
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func (srv *Server) findPeers() {
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far := srv.Self().ID
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for i := range far {
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far[i] = ^far[i]
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}
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closeToSelf := srv.ntab.Lookup(srv.Self().ID)
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farFromSelf := srv.ntab.Lookup(far)
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for i := 0; i < len(closeToSelf) || i < len(farFromSelf); i++ {
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if i < len(closeToSelf) {
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srv.peerConnect <- closeToSelf[i]
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}
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if i < len(farFromSelf) {
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srv.peerConnect <- farFromSelf[i]
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}
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}
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}
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func (srv *Server) startPeer(fd net.Conn, dest *discover.Node) {
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// TODO: handle/store session token
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fd.SetDeadline(time.Now().Add(handshakeTimeout))
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@ -368,7 +363,6 @@ func (srv *Server) startPeer(fd net.Conn, dest *discover.Node) {
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glog.V(logger.Debug).Infof("Handshake with %v failed: %v", fd.RemoteAddr(), err)
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return
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}
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conn.MsgReadWriter = &netWrapper{
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wrapped: conn.MsgReadWriter,
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conn: fd, rtimeout: frameReadTimeout, wtimeout: frameWriteTimeout,
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@ -379,24 +373,27 @@ func (srv *Server) startPeer(fd net.Conn, dest *discover.Node) {
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p.politeDisconnect(reason)
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return
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}
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// The handshakes are done and it passed all checks.
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// Spawn the Peer loops.
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go srv.runPeer(p)
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}
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func (srv *Server) runPeer(p *Peer) {
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glog.V(logger.Debug).Infof("Added %v\n", p)
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srvjslog.LogJson(&logger.P2PConnected{
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RemoteId: fmt.Sprintf("%x", conn.ID[:]),
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RemoteAddress: fd.RemoteAddr().String(),
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RemoteVersionString: conn.Name,
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RemoteId: p.ID().String(),
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RemoteAddress: p.RemoteAddr().String(),
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RemoteVersionString: p.Name(),
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NumConnections: srv.PeerCount(),
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})
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if srv.newPeerHook != nil {
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srv.newPeerHook(p)
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}
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discreason := p.run()
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srv.removePeer(p)
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glog.V(logger.Debug).Infof("Removed %v (%v)\n", p, discreason)
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srvjslog.LogJson(&logger.P2PDisconnected{
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RemoteId: fmt.Sprintf("%x", conn.ID[:]),
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RemoteId: p.ID().String(),
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NumConnections: srv.PeerCount(),
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})
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}
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@ -404,6 +401,14 @@ func (srv *Server) startPeer(fd net.Conn, dest *discover.Node) {
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func (srv *Server) addPeer(id discover.NodeID, p *Peer) (bool, DiscReason) {
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srv.lock.Lock()
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defer srv.lock.Unlock()
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if ok, reason := srv.checkPeer(id); !ok {
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return false, reason
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}
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srv.peers[id] = p
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return true, 0
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}
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func (srv *Server) checkPeer(id discover.NodeID) (bool, DiscReason) {
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switch {
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case !srv.running:
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return false, DiscQuitting
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@ -413,9 +418,9 @@ func (srv *Server) addPeer(id discover.NodeID, p *Peer) (bool, DiscReason) {
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return false, DiscAlreadyConnected
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case id == srv.Self().ID:
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return false, DiscSelf
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default:
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return true, 0
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}
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srv.peers[id] = p
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return true, 0
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}
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func (srv *Server) removePeer(p *Peer) {
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