You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
358 lines
10 KiB
358 lines
10 KiB
package p2p
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"math/rand"
|
|
"reflect"
|
|
"time"
|
|
|
|
wire "github.com/tendermint/go-wire"
|
|
cmn "github.com/tendermint/tmlibs/common"
|
|
)
|
|
|
|
const (
|
|
// PexChannel is a channel for PEX messages
|
|
PexChannel = byte(0x00)
|
|
|
|
// period to ensure peers connected
|
|
defaultEnsurePeersPeriod = 30 * time.Second
|
|
minNumOutboundPeers = 10
|
|
maxPexMessageSize = 1048576 // 1MB
|
|
|
|
// maximum messages one peer can send to us during `msgCountByPeerFlushInterval`
|
|
defaultMaxMsgCountByPeer = 1000
|
|
msgCountByPeerFlushInterval = 1 * time.Hour
|
|
)
|
|
|
|
// PEXReactor handles PEX (peer exchange) and ensures that an
|
|
// adequate number of peers are connected to the switch.
|
|
//
|
|
// It uses `AddrBook` (address book) to store `NetAddress`es of the peers.
|
|
//
|
|
// ## Preventing abuse
|
|
//
|
|
// For now, it just limits the number of messages from one peer to
|
|
// `defaultMaxMsgCountByPeer` messages per `msgCountByPeerFlushInterval` (1000
|
|
// msg/hour).
|
|
//
|
|
// NOTE [2017-01-17]:
|
|
// Limiting is fine for now. Maybe down the road we want to keep track of the
|
|
// quality of peer messages so if peerA keeps telling us about peers we can't
|
|
// connect to then maybe we should care less about peerA. But I don't think
|
|
// that kind of complexity is priority right now.
|
|
type PEXReactor struct {
|
|
BaseReactor
|
|
|
|
sw *Switch
|
|
book *AddrBook
|
|
ensurePeersPeriod time.Duration
|
|
|
|
// tracks message count by peer, so we can prevent abuse
|
|
msgCountByPeer *cmn.CMap
|
|
maxMsgCountByPeer uint16
|
|
}
|
|
|
|
// NewPEXReactor creates new PEX reactor.
|
|
func NewPEXReactor(b *AddrBook) *PEXReactor {
|
|
r := &PEXReactor{
|
|
book: b,
|
|
ensurePeersPeriod: defaultEnsurePeersPeriod,
|
|
msgCountByPeer: cmn.NewCMap(),
|
|
maxMsgCountByPeer: defaultMaxMsgCountByPeer,
|
|
}
|
|
r.BaseReactor = *NewBaseReactor("PEXReactor", r)
|
|
return r
|
|
}
|
|
|
|
// OnStart implements BaseService
|
|
func (r *PEXReactor) OnStart() error {
|
|
r.BaseReactor.OnStart()
|
|
r.book.Start()
|
|
go r.ensurePeersRoutine()
|
|
go r.flushMsgCountByPeer()
|
|
return nil
|
|
}
|
|
|
|
// OnStop implements BaseService
|
|
func (r *PEXReactor) OnStop() {
|
|
r.BaseReactor.OnStop()
|
|
r.book.Stop()
|
|
}
|
|
|
|
// GetChannels implements Reactor
|
|
func (r *PEXReactor) GetChannels() []*ChannelDescriptor {
|
|
return []*ChannelDescriptor{
|
|
&ChannelDescriptor{
|
|
ID: PexChannel,
|
|
Priority: 1,
|
|
SendQueueCapacity: 10,
|
|
},
|
|
}
|
|
}
|
|
|
|
// AddPeer implements Reactor by adding peer to the address book (if inbound)
|
|
// or by requesting more addresses (if outbound).
|
|
func (r *PEXReactor) AddPeer(p *Peer) {
|
|
if p.IsOutbound() {
|
|
// For outbound peers, the address is already in the books.
|
|
// Either it was added in DialSeeds or when we
|
|
// received the peer's address in r.Receive
|
|
if r.book.NeedMoreAddrs() {
|
|
r.RequestPEX(p)
|
|
}
|
|
} else { // For inbound connections, the peer is its own source
|
|
addr, err := NewNetAddressString(p.ListenAddr)
|
|
if err != nil {
|
|
// this should never happen
|
|
r.Logger.Error("Error in AddPeer: invalid peer address", "addr", p.ListenAddr, "error", err)
|
|
return
|
|
}
|
|
r.book.AddAddress(addr, addr)
|
|
}
|
|
}
|
|
|
|
// RemovePeer implements Reactor.
|
|
func (r *PEXReactor) RemovePeer(p *Peer, reason interface{}) {
|
|
// If we aren't keeping track of local temp data for each peer here, then we
|
|
// don't have to do anything.
|
|
}
|
|
|
|
// Receive implements Reactor by handling incoming PEX messages.
|
|
func (r *PEXReactor) Receive(chID byte, src *Peer, msgBytes []byte) {
|
|
srcAddr := src.Connection().RemoteAddress
|
|
srcAddrStr := srcAddr.String()
|
|
|
|
r.IncrementMsgCountForPeer(srcAddrStr)
|
|
if r.ReachedMaxMsgCountForPeer(srcAddrStr) {
|
|
r.Logger.Error("Maximum number of messages reached for peer", "peer", srcAddrStr)
|
|
// TODO remove src from peers?
|
|
return
|
|
}
|
|
|
|
_, msg, err := DecodeMessage(msgBytes)
|
|
if err != nil {
|
|
r.Logger.Error("Error decoding message", "error", err)
|
|
return
|
|
}
|
|
r.Logger.Info("Received message", "msg", msg)
|
|
|
|
switch msg := msg.(type) {
|
|
case *pexRequestMessage:
|
|
// src requested some peers.
|
|
r.SendAddrs(src, r.book.GetSelection())
|
|
case *pexAddrsMessage:
|
|
// We received some peer addresses from src.
|
|
// (We don't want to get spammed with bad peers)
|
|
for _, addr := range msg.Addrs {
|
|
if addr != nil {
|
|
r.book.AddAddress(addr, srcAddr)
|
|
}
|
|
}
|
|
default:
|
|
r.Logger.Error(fmt.Sprintf("Unknown message type %v", reflect.TypeOf(msg)))
|
|
}
|
|
}
|
|
|
|
// RequestPEX asks peer for more addresses.
|
|
func (r *PEXReactor) RequestPEX(p *Peer) {
|
|
p.Send(PexChannel, struct{ PexMessage }{&pexRequestMessage{}})
|
|
}
|
|
|
|
// SendAddrs sends addrs to the peer.
|
|
func (r *PEXReactor) SendAddrs(p *Peer, addrs []*NetAddress) {
|
|
p.Send(PexChannel, struct{ PexMessage }{&pexAddrsMessage{Addrs: addrs}})
|
|
}
|
|
|
|
// SetEnsurePeersPeriod sets period to ensure peers connected.
|
|
func (r *PEXReactor) SetEnsurePeersPeriod(d time.Duration) {
|
|
r.ensurePeersPeriod = d
|
|
}
|
|
|
|
// SetMaxMsgCountByPeer sets maximum messages one peer can send to us during 'msgCountByPeerFlushInterval'.
|
|
func (r *PEXReactor) SetMaxMsgCountByPeer(v uint16) {
|
|
r.maxMsgCountByPeer = v
|
|
}
|
|
|
|
// ReachedMaxMsgCountForPeer returns true if we received too many
|
|
// messages from peer with address `addr`.
|
|
// NOTE: assumes the value in the CMap is non-nil
|
|
func (r *PEXReactor) ReachedMaxMsgCountForPeer(addr string) bool {
|
|
return r.msgCountByPeer.Get(addr).(uint16) >= r.maxMsgCountByPeer
|
|
}
|
|
|
|
// Increment or initialize the msg count for the peer in the CMap
|
|
func (r *PEXReactor) IncrementMsgCountForPeer(addr string) {
|
|
var count uint16
|
|
countI := r.msgCountByPeer.Get(addr)
|
|
if countI != nil {
|
|
count = countI.(uint16)
|
|
}
|
|
count++
|
|
r.msgCountByPeer.Set(addr, count)
|
|
}
|
|
|
|
// Ensures that sufficient peers are connected. (continuous)
|
|
func (r *PEXReactor) ensurePeersRoutine() {
|
|
// Randomize when routine starts
|
|
ensurePeersPeriodMs := r.ensurePeersPeriod.Nanoseconds() / 1e6
|
|
time.Sleep(time.Duration(rand.Int63n(ensurePeersPeriodMs)) * time.Millisecond)
|
|
|
|
// fire once immediately.
|
|
r.ensurePeers()
|
|
|
|
// fire periodically
|
|
ticker := time.NewTicker(r.ensurePeersPeriod)
|
|
|
|
for {
|
|
select {
|
|
case <-ticker.C:
|
|
r.ensurePeers()
|
|
case <-r.Quit:
|
|
ticker.Stop()
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
// ensurePeers ensures that sufficient peers are connected. (once)
|
|
//
|
|
// Old bucket / New bucket are arbitrary categories to denote whether an
|
|
// address is vetted or not, and this needs to be determined over time via a
|
|
// heuristic that we haven't perfected yet, or, perhaps is manually edited by
|
|
// the node operator. It should not be used to compute what addresses are
|
|
// already connected or not.
|
|
//
|
|
// TODO Basically, we need to work harder on our good-peer/bad-peer marking.
|
|
// What we're currently doing in terms of marking good/bad peers is just a
|
|
// placeholder. It should not be the case that an address becomes old/vetted
|
|
// upon a single successful connection.
|
|
func (r *PEXReactor) ensurePeers() {
|
|
numOutPeers, _, numDialing := r.Switch.NumPeers()
|
|
numToDial := minNumOutboundPeers - (numOutPeers + numDialing)
|
|
r.Logger.Info("Ensure peers", "numOutPeers", numOutPeers, "numDialing", numDialing, "numToDial", numToDial)
|
|
if numToDial <= 0 {
|
|
return
|
|
}
|
|
|
|
toDial := make(map[string]*NetAddress)
|
|
|
|
// Try to pick numToDial addresses to dial.
|
|
for i := 0; i < numToDial; i++ {
|
|
// The purpose of newBias is to first prioritize old (more vetted) peers
|
|
// when we have few connections, but to allow for new (less vetted) peers
|
|
// if we already have many connections. This algorithm isn't perfect, but
|
|
// it somewhat ensures that we prioritize connecting to more-vetted
|
|
// peers.
|
|
newBias := cmn.MinInt(numOutPeers, 8)*10 + 10
|
|
var picked *NetAddress
|
|
// Try to fetch a new peer 3 times.
|
|
// This caps the maximum number of tries to 3 * numToDial.
|
|
for j := 0; j < 3; j++ {
|
|
try := r.book.PickAddress(newBias)
|
|
if try == nil {
|
|
break
|
|
}
|
|
_, alreadySelected := toDial[try.IP.String()]
|
|
alreadyDialing := r.Switch.IsDialing(try)
|
|
alreadyConnected := r.Switch.Peers().Has(try.IP.String())
|
|
if alreadySelected || alreadyDialing || alreadyConnected {
|
|
// r.Logger.Info("Cannot dial address", "addr", try,
|
|
// "alreadySelected", alreadySelected,
|
|
// "alreadyDialing", alreadyDialing,
|
|
// "alreadyConnected", alreadyConnected)
|
|
continue
|
|
} else {
|
|
r.Logger.Info("Will dial address", "addr", try)
|
|
picked = try
|
|
break
|
|
}
|
|
}
|
|
if picked == nil {
|
|
continue
|
|
}
|
|
toDial[picked.IP.String()] = picked
|
|
}
|
|
|
|
// Dial picked addresses
|
|
for _, item := range toDial {
|
|
go func(picked *NetAddress) {
|
|
_, err := r.Switch.DialPeerWithAddress(picked, false)
|
|
if err != nil {
|
|
r.book.MarkAttempt(picked)
|
|
}
|
|
}(item)
|
|
}
|
|
|
|
// If we need more addresses, pick a random peer and ask for more.
|
|
if r.book.NeedMoreAddrs() {
|
|
if peers := r.Switch.Peers().List(); len(peers) > 0 {
|
|
i := rand.Int() % len(peers)
|
|
peer := peers[i]
|
|
r.Logger.Info("No addresses to dial. Sending pexRequest to random peer", "peer", peer)
|
|
r.RequestPEX(peer)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (r *PEXReactor) flushMsgCountByPeer() {
|
|
ticker := time.NewTicker(msgCountByPeerFlushInterval)
|
|
|
|
for {
|
|
select {
|
|
case <-ticker.C:
|
|
r.msgCountByPeer.Clear()
|
|
case <-r.Quit:
|
|
ticker.Stop()
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// Messages
|
|
|
|
const (
|
|
msgTypeRequest = byte(0x01)
|
|
msgTypeAddrs = byte(0x02)
|
|
)
|
|
|
|
// PexMessage is a primary type for PEX messages. Underneath, it could contain
|
|
// either pexRequestMessage, or pexAddrsMessage messages.
|
|
type PexMessage interface{}
|
|
|
|
var _ = wire.RegisterInterface(
|
|
struct{ PexMessage }{},
|
|
wire.ConcreteType{&pexRequestMessage{}, msgTypeRequest},
|
|
wire.ConcreteType{&pexAddrsMessage{}, msgTypeAddrs},
|
|
)
|
|
|
|
// DecodeMessage implements interface registered above.
|
|
func DecodeMessage(bz []byte) (msgType byte, msg PexMessage, err error) {
|
|
msgType = bz[0]
|
|
n := new(int)
|
|
r := bytes.NewReader(bz)
|
|
msg = wire.ReadBinary(struct{ PexMessage }{}, r, maxPexMessageSize, n, &err).(struct{ PexMessage }).PexMessage
|
|
return
|
|
}
|
|
|
|
/*
|
|
A pexRequestMessage requests additional peer addresses.
|
|
*/
|
|
type pexRequestMessage struct {
|
|
}
|
|
|
|
func (m *pexRequestMessage) String() string {
|
|
return "[pexRequest]"
|
|
}
|
|
|
|
/*
|
|
A message with announced peer addresses.
|
|
*/
|
|
type pexAddrsMessage struct {
|
|
Addrs []*NetAddress
|
|
}
|
|
|
|
func (m *pexAddrsMessage) String() string {
|
|
return fmt.Sprintf("[pexAddrs %v]", m.Addrs)
|
|
}
|