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278 lines
6.0 KiB
278 lines
6.0 KiB
package p2p
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import (
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"bytes"
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"errors"
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"fmt"
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"io"
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"sync/atomic"
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"time"
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. "github.com/tendermint/tendermint/binary"
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. "github.com/tendermint/tendermint/common"
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)
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var pexErrInvalidMessage = errors.New("Invalid PEX message")
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const (
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PexCh = byte(0x00)
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ensurePeersPeriodSeconds = 30
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minNumOutboundPeers = 10
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maxNumPeers = 50
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)
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/*
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PeerManager handles PEX (peer exchange) and ensures that an
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adequate number of peers are connected to the switch.
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*/
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type PeerManager struct {
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sw *Switch
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swEvents chan interface{}
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quit chan struct{}
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started uint32
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stopped uint32
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book *AddrBook
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}
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func NewPeerManager(sw *Switch, book *AddrBook) *PeerManager {
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swEvents := make(chan interface{})
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sw.AddEventListener("PeerManager.swEvents", swEvents)
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pm := &PeerManager{
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sw: sw,
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swEvents: swEvents,
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quit: make(chan struct{}),
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book: book,
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}
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return pm
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}
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func (pm *PeerManager) Start() {
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if atomic.CompareAndSwapUint32(&pm.started, 0, 1) {
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log.Info("Starting PeerManager")
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go pm.switchEventsRoutine()
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go pm.requestRoutine()
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go pm.ensurePeersRoutine()
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}
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}
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func (pm *PeerManager) Stop() {
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if atomic.CompareAndSwapUint32(&pm.stopped, 0, 1) {
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log.Info("Stopping PeerManager")
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close(pm.quit)
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close(pm.swEvents)
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}
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}
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// Asks peer for more addresses.
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func (pm *PeerManager) RequestPEX(peer *Peer) {
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peer.TrySend(PexCh, &pexRequestMessage{})
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}
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func (pm *PeerManager) SendAddrs(peer *Peer, addrs []*NetAddress) {
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peer.Send(PexCh, &pexAddrsMessage{Addrs: addrs})
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}
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// For new outbound peers, announce our listener addresses if any,
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// and if .book needs more addresses, ask for them.
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func (pm *PeerManager) switchEventsRoutine() {
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for {
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swEvent, ok := <-pm.swEvents
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if !ok {
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break
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}
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switch swEvent.(type) {
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case SwitchEventNewPeer:
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event := swEvent.(SwitchEventNewPeer)
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if event.Peer.IsOutbound() {
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pm.SendAddrs(event.Peer, pm.book.OurAddresses())
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if pm.book.NeedMoreAddrs() {
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pm.RequestPEX(event.Peer)
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}
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}
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case SwitchEventDonePeer:
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// TODO
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}
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}
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}
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// Ensures that sufficient peers are connected. (continuous)
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func (pm *PeerManager) ensurePeersRoutine() {
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// fire once immediately.
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pm.ensurePeers()
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// fire periodically
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timer := NewRepeatTimer(ensurePeersPeriodSeconds * time.Second)
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FOR_LOOP:
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for {
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select {
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case <-timer.Ch:
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pm.ensurePeers()
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case <-pm.quit:
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break FOR_LOOP
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}
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}
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// Cleanup
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timer.Stop()
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}
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// Ensures that sufficient peers are connected. (once)
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func (pm *PeerManager) ensurePeers() {
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numOutPeers, _, numDialing := pm.sw.NumPeers()
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numToDial := minNumOutboundPeers - (numOutPeers + numDialing)
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if numToDial <= 0 {
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return
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}
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toDial := NewCMap()
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// Try to pick numToDial addresses to dial.
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// TODO: improve logic.
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for i := 0; i < numToDial; i++ {
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newBias := MinInt(numOutPeers, 8)*10 + 10
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var picked *NetAddress
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// Try to fetch a new peer 3 times.
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// This caps the maximum number of tries to 3 * numToDial.
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for j := 0; i < 3; j++ {
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picked = pm.book.PickAddress(newBias)
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if picked == nil {
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return
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}
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if toDial.Has(picked.String()) ||
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pm.sw.IsDialing(picked) ||
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pm.sw.Peers().Has(picked.String()) {
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continue
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} else {
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break
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}
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}
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if picked == nil {
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continue
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}
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toDial.Set(picked.String(), picked)
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}
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// Dial picked addresses
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for _, item := range toDial.Values() {
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picked := item.(*NetAddress)
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go func() {
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_, err := pm.sw.DialPeerWithAddress(picked)
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if err != nil {
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pm.book.MarkAttempt(picked)
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}
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}()
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}
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}
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// Handles incoming PEX messages.
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func (pm *PeerManager) requestRoutine() {
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for {
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inMsg, ok := pm.sw.Receive(PexCh) // {Peer, Time, Packet}
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if !ok {
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// Client has stopped
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break
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}
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// decode message
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msg := decodeMessage(inMsg.Bytes)
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log.Info("requestRoutine received %v", msg)
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switch msg.(type) {
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case *pexRequestMessage:
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// inMsg.MConn.Peer requested some peers.
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// TODO: prevent abuse.
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addrs := pm.book.GetSelection()
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msg := &pexAddrsMessage{Addrs: addrs}
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queued := inMsg.MConn.Peer.TrySend(PexCh, msg)
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if !queued {
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// ignore
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}
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case *pexAddrsMessage:
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// We received some peer addresses from inMsg.MConn.Peer.
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// TODO: prevent abuse.
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// (We don't want to get spammed with bad peers)
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srcAddr := inMsg.MConn.RemoteAddress
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for _, addr := range msg.(*pexAddrsMessage).Addrs {
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pm.book.AddAddress(addr, srcAddr)
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}
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default:
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// Ignore unknown message.
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// pm.sw.StopPeerForError(inMsg.MConn.Peer, pexErrInvalidMessage)
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}
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}
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// Cleanup
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}
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//-----------------------------------------------------------------------------
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/* Messages */
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const (
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msgTypeUnknown = byte(0x00)
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msgTypeRequest = byte(0x01)
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msgTypeAddrs = byte(0x02)
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)
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// TODO: check for unnecessary extra bytes at the end.
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func decodeMessage(bz []byte) (msg interface{}) {
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var n int64
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var err error
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// log.Debug("decoding msg bytes: %X", bz)
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switch bz[0] {
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case msgTypeRequest:
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return &pexRequestMessage{}
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case msgTypeAddrs:
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return readPexAddrsMessage(bytes.NewReader(bz[1:]), &n, &err)
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default:
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return nil
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}
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}
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/*
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A pexRequestMessage requests additional peer addresses.
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*/
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type pexRequestMessage struct {
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}
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func (m *pexRequestMessage) WriteTo(w io.Writer) (n int64, err error) {
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WriteByte(w, msgTypeRequest, &n, &err)
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return
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}
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func (m *pexRequestMessage) String() string {
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return "[pexRequest]"
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}
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/*
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A message with announced peer addresses.
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*/
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type pexAddrsMessage struct {
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Addrs []*NetAddress
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}
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func readPexAddrsMessage(r io.Reader, n *int64, err *error) *pexAddrsMessage {
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numAddrs := int(ReadUInt32(r, n, err))
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addrs := []*NetAddress{}
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for i := 0; i < numAddrs; i++ {
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addr := ReadNetAddress(r, n, err)
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addrs = append(addrs, addr)
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}
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return &pexAddrsMessage{
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Addrs: addrs,
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}
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}
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func (m *pexAddrsMessage) WriteTo(w io.Writer) (n int64, err error) {
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WriteByte(w, msgTypeAddrs, &n, &err)
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WriteUInt32(w, uint32(len(m.Addrs)), &n, &err)
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for _, addr := range m.Addrs {
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WriteBinary(w, addr, &n, &err)
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}
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return
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}
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func (m *pexAddrsMessage) String() string {
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return fmt.Sprintf("[pexAddrs %v]", m.Addrs)
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}
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