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.
540 lines
14 KiB
540 lines
14 KiB
package p2p
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"math/rand"
|
|
"reflect"
|
|
"sort"
|
|
"time"
|
|
|
|
"github.com/pkg/errors"
|
|
wire "github.com/tendermint/go-wire"
|
|
cmn "github.com/tendermint/tmlibs/common"
|
|
)
|
|
|
|
const (
|
|
// PexChannel is a channel for PEX messages
|
|
PexChannel = byte(0x00)
|
|
|
|
maxPexMessageSize = 1048576 // 1MB
|
|
|
|
// ensure we have enough peers
|
|
defaultEnsurePeersPeriod = 30 * time.Second
|
|
defaultMinNumOutboundPeers = 10
|
|
|
|
// Seed/Crawler constants
|
|
// TODO:
|
|
// We want seeds to only advertise good peers.
|
|
// Peers are marked by external mechanisms.
|
|
// We need a config value that can be set to be
|
|
// on the order of how long it would take before a good
|
|
// peer is marked good.
|
|
defaultSeedDisconnectWaitPeriod = 2 * time.Minute // disconnect after this
|
|
defaultCrawlPeerInterval = 2 * time.Minute // dont redial for this. TODO: back-off
|
|
defaultCrawlPeersPeriod = 30 * time.Second // check some peers every this
|
|
)
|
|
|
|
// 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
|
|
//
|
|
// Only accept pexAddrsMsg from peers we sent a corresponding pexRequestMsg too.
|
|
// Only accept one pexRequestMsg every ~defaultEnsurePeersPeriod.
|
|
type PEXReactor struct {
|
|
BaseReactor
|
|
|
|
book *AddrBook
|
|
config *PEXReactorConfig
|
|
ensurePeersPeriod time.Duration
|
|
|
|
// maps to prevent abuse
|
|
requestsSent *cmn.CMap // ID->struct{}: unanswered send requests
|
|
lastReceivedRequests *cmn.CMap // ID->time.Time: last time peer requested from us
|
|
}
|
|
|
|
// PEXReactorConfig holds reactor specific configuration data.
|
|
type PEXReactorConfig struct {
|
|
// Seed/Crawler mode
|
|
SeedMode bool
|
|
|
|
// Seeds is a list of addresses reactor may use
|
|
// if it can't connect to peers in the addrbook.
|
|
Seeds []string
|
|
}
|
|
|
|
// NewPEXReactor creates new PEX reactor.
|
|
func NewPEXReactor(b *AddrBook, config *PEXReactorConfig) *PEXReactor {
|
|
r := &PEXReactor{
|
|
book: b,
|
|
config: config,
|
|
ensurePeersPeriod: defaultEnsurePeersPeriod,
|
|
requestsSent: cmn.NewCMap(),
|
|
lastReceivedRequests: cmn.NewCMap(),
|
|
}
|
|
r.BaseReactor = *NewBaseReactor("PEXReactor", r)
|
|
return r
|
|
}
|
|
|
|
// OnStart implements BaseService
|
|
func (r *PEXReactor) OnStart() error {
|
|
if err := r.BaseReactor.OnStart(); err != nil {
|
|
return err
|
|
}
|
|
err := r.book.Start()
|
|
if err != nil && err != cmn.ErrAlreadyStarted {
|
|
return err
|
|
}
|
|
|
|
// return err if user provided a bad seed address
|
|
if err := r.checkSeeds(); err != nil {
|
|
return err
|
|
}
|
|
|
|
// Check if this node should run
|
|
// in seed/crawler mode
|
|
if r.config.SeedMode {
|
|
go r.crawlPeersRoutine()
|
|
} else {
|
|
go r.ensurePeersRoutine()
|
|
}
|
|
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{
|
|
{
|
|
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 via DialPeersAsync or r.Receive.
|
|
// Ask it for more peers if we need.
|
|
if r.book.NeedMoreAddrs() {
|
|
r.RequestAddrs(p)
|
|
}
|
|
} else {
|
|
// For inbound peers, the peer is its own source,
|
|
// and its NodeInfo has already been validated.
|
|
// Let the ensurePeersRoutine handle asking for more
|
|
// peers when we need - we don't trust inbound peers as much.
|
|
addr := p.NodeInfo().NetAddress()
|
|
r.book.AddAddress(addr, addr)
|
|
}
|
|
}
|
|
|
|
// RemovePeer implements Reactor.
|
|
func (r *PEXReactor) RemovePeer(p Peer, reason interface{}) {
|
|
id := string(p.ID())
|
|
r.requestsSent.Delete(id)
|
|
r.lastReceivedRequests.Delete(id)
|
|
}
|
|
|
|
// Receive implements Reactor by handling incoming PEX messages.
|
|
func (r *PEXReactor) Receive(chID byte, src Peer, msgBytes []byte) {
|
|
_, msg, err := DecodeMessage(msgBytes)
|
|
if err != nil {
|
|
r.Logger.Error("Error decoding message", "err", err)
|
|
return
|
|
}
|
|
r.Logger.Debug("Received message", "src", src, "chId", chID, "msg", msg)
|
|
|
|
switch msg := msg.(type) {
|
|
case *pexRequestMessage:
|
|
// Check we're not receiving too many requests
|
|
if err := r.receiveRequest(src); err != nil {
|
|
r.Switch.StopPeerForError(src, err)
|
|
return
|
|
}
|
|
|
|
// Seeds disconnect after sending a batch of addrs
|
|
if r.config.SeedMode {
|
|
// TODO: should we be more selective ?
|
|
r.SendAddrs(src, r.book.GetSelection())
|
|
r.Switch.StopPeerGracefully(src)
|
|
} else {
|
|
r.SendAddrs(src, r.book.GetSelection())
|
|
}
|
|
|
|
case *pexAddrsMessage:
|
|
// If we asked for addresses, add them to the book
|
|
if err := r.ReceiveAddrs(msg.Addrs, src); err != nil {
|
|
r.Switch.StopPeerForError(src, err)
|
|
return
|
|
}
|
|
default:
|
|
r.Logger.Error(fmt.Sprintf("Unknown message type %v", reflect.TypeOf(msg)))
|
|
}
|
|
}
|
|
|
|
func (r *PEXReactor) receiveRequest(src Peer) error {
|
|
id := string(src.ID())
|
|
v := r.lastReceivedRequests.Get(id)
|
|
if v == nil {
|
|
// initialize with empty time
|
|
lastReceived := time.Time{}
|
|
r.lastReceivedRequests.Set(id, lastReceived)
|
|
return nil
|
|
}
|
|
|
|
lastReceived := v.(time.Time)
|
|
if lastReceived.Equal(time.Time{}) {
|
|
// first time gets a free pass. then we start tracking the time
|
|
lastReceived = time.Now()
|
|
r.lastReceivedRequests.Set(id, lastReceived)
|
|
return nil
|
|
}
|
|
|
|
now := time.Now()
|
|
if now.Sub(lastReceived) < r.ensurePeersPeriod/3 {
|
|
return fmt.Errorf("Peer (%v) is sending too many PEX requests. Disconnecting", src.ID())
|
|
}
|
|
r.lastReceivedRequests.Set(id, now)
|
|
return nil
|
|
}
|
|
|
|
// RequestAddrs asks peer for more addresses if we do not already
|
|
// have a request out for this peer.
|
|
func (r *PEXReactor) RequestAddrs(p Peer) {
|
|
id := string(p.ID())
|
|
if r.requestsSent.Has(id) {
|
|
return
|
|
}
|
|
r.requestsSent.Set(id, struct{}{})
|
|
p.Send(PexChannel, struct{ PexMessage }{&pexRequestMessage{}})
|
|
}
|
|
|
|
// ReceiveAddrs adds the given addrs to the addrbook if theres an open
|
|
// request for this peer and deletes the open request.
|
|
// If there's no open request for the src peer, it returns an error.
|
|
func (r *PEXReactor) ReceiveAddrs(addrs []*NetAddress, src Peer) error {
|
|
id := string(src.ID())
|
|
|
|
if !r.requestsSent.Has(id) {
|
|
return errors.New("Received unsolicited pexAddrsMessage")
|
|
}
|
|
|
|
r.requestsSent.Delete(id)
|
|
|
|
srcAddr := src.NodeInfo().NetAddress()
|
|
for _, netAddr := range addrs {
|
|
if netAddr != nil {
|
|
r.book.AddAddress(netAddr, srcAddr)
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// SendAddrs sends addrs to the peer.
|
|
func (r *PEXReactor) SendAddrs(p Peer, netAddrs []*NetAddress) {
|
|
p.Send(PexChannel, struct{ PexMessage }{&pexAddrsMessage{Addrs: netAddrs}})
|
|
}
|
|
|
|
// SetEnsurePeersPeriod sets period to ensure peers connected.
|
|
func (r *PEXReactor) SetEnsurePeersPeriod(d time.Duration) {
|
|
r.ensurePeersPeriod = d
|
|
}
|
|
|
|
// 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.
|
|
// ensures we dial the seeds right away if the book is empty
|
|
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)
|
|
//
|
|
// 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.
|
|
func (r *PEXReactor) ensurePeers() {
|
|
numOutPeers, numInPeers, numDialing := r.Switch.NumPeers()
|
|
numToDial := defaultMinNumOutboundPeers - (numOutPeers + numDialing)
|
|
r.Logger.Info("Ensure peers", "numOutPeers", numOutPeers, "numDialing", numDialing, "numToDial", numToDial)
|
|
if numToDial <= 0 {
|
|
return
|
|
}
|
|
|
|
// bias to prefer more vetted peers when we have fewer connections.
|
|
// not perfect, but somewhate ensures that we prioritize connecting to more-vetted
|
|
// NOTE: range here is [10, 90]. Too high ?
|
|
newBias := cmn.MinInt(numOutPeers, 8)*10 + 10
|
|
|
|
toDial := make(map[ID]*NetAddress)
|
|
// Try maxAttempts times to pick numToDial addresses to dial
|
|
maxAttempts := numToDial * 3
|
|
for i := 0; i < maxAttempts && len(toDial) < numToDial; i++ {
|
|
try := r.book.PickAddress(newBias)
|
|
if try == nil {
|
|
continue
|
|
}
|
|
if _, selected := toDial[try.ID]; selected {
|
|
continue
|
|
}
|
|
if dialling := r.Switch.IsDialing(try.ID); dialling {
|
|
continue
|
|
}
|
|
if connected := r.Switch.Peers().Has(try.ID); connected {
|
|
continue
|
|
}
|
|
r.Logger.Info("Will dial address", "addr", try)
|
|
toDial[try.ID] = try
|
|
}
|
|
|
|
// 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() {
|
|
peers := r.Switch.Peers().List()
|
|
peersCount := len(peers)
|
|
if peersCount > 0 {
|
|
peer := peers[rand.Int()%peersCount] // nolint: gas
|
|
r.Logger.Info("We need more addresses. Sending pexRequest to random peer", "peer", peer)
|
|
r.RequestAddrs(peer)
|
|
}
|
|
}
|
|
|
|
// If we are not connected to nor dialing anybody, fallback to dialing a seed.
|
|
if numOutPeers+numInPeers+numDialing+len(toDial) == 0 {
|
|
r.Logger.Info("No addresses to dial nor connected peers. Falling back to seeds")
|
|
r.dialSeeds()
|
|
}
|
|
}
|
|
|
|
// check seed addresses are well formed
|
|
func (r *PEXReactor) checkSeeds() error {
|
|
lSeeds := len(r.config.Seeds)
|
|
if lSeeds == 0 {
|
|
return nil
|
|
}
|
|
_, errs := NewNetAddressStrings(r.config.Seeds)
|
|
for _, err := range errs {
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// randomly dial seeds until we connect to one or exhaust them
|
|
func (r *PEXReactor) dialSeeds() {
|
|
lSeeds := len(r.config.Seeds)
|
|
if lSeeds == 0 {
|
|
return
|
|
}
|
|
seedAddrs, _ := NewNetAddressStrings(r.config.Seeds)
|
|
|
|
perm := r.Switch.rng.Perm(lSeeds)
|
|
for _, i := range perm {
|
|
// dial a random seed
|
|
seedAddr := seedAddrs[i]
|
|
peer, err := r.Switch.DialPeerWithAddress(seedAddr, false)
|
|
if err != nil {
|
|
r.Switch.Logger.Error("Error dialing seed", "err", err, "seed", seedAddr)
|
|
} else {
|
|
r.Switch.Logger.Info("Connected to seed", "peer", peer)
|
|
return
|
|
}
|
|
}
|
|
r.Switch.Logger.Error("Couldn't connect to any seeds")
|
|
}
|
|
|
|
//----------------------------------------------------------
|
|
|
|
// Explores the network searching for more peers. (continuous)
|
|
// Seed/Crawler Mode causes this node to quickly disconnect
|
|
// from peers, except other seed nodes.
|
|
func (r *PEXReactor) crawlPeersRoutine() {
|
|
// Do an initial crawl
|
|
r.crawlPeers()
|
|
|
|
// Fire periodically
|
|
ticker := time.NewTicker(defaultCrawlPeersPeriod)
|
|
|
|
for {
|
|
select {
|
|
case <-ticker.C:
|
|
r.attemptDisconnects()
|
|
r.crawlPeers()
|
|
case <-r.Quit:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
// crawlPeerInfo handles temporary data needed for the
|
|
// network crawling performed during seed/crawler mode.
|
|
type crawlPeerInfo struct {
|
|
// The listening address of a potential peer we learned about
|
|
Addr *NetAddress
|
|
|
|
// The last time we attempt to reach this address
|
|
LastAttempt time.Time
|
|
|
|
// The last time we successfully reached this address
|
|
LastSuccess time.Time
|
|
}
|
|
|
|
// oldestFirst implements sort.Interface for []crawlPeerInfo
|
|
// based on the LastAttempt field.
|
|
type oldestFirst []crawlPeerInfo
|
|
|
|
func (of oldestFirst) Len() int { return len(of) }
|
|
func (of oldestFirst) Swap(i, j int) { of[i], of[j] = of[j], of[i] }
|
|
func (of oldestFirst) Less(i, j int) bool { return of[i].LastAttempt.Before(of[j].LastAttempt) }
|
|
|
|
// getPeersToCrawl returns addresses of potential peers that we wish to validate.
|
|
// NOTE: The status information is ordered as described above.
|
|
func (r *PEXReactor) getPeersToCrawl() []crawlPeerInfo {
|
|
var of oldestFirst
|
|
|
|
// TODO: be more selective
|
|
addrs := r.book.ListOfKnownAddresses()
|
|
for _, addr := range addrs {
|
|
if len(addr.ID()) == 0 {
|
|
continue // dont use peers without id
|
|
}
|
|
|
|
of = append(of, crawlPeerInfo{
|
|
Addr: addr.Addr,
|
|
LastAttempt: addr.LastAttempt,
|
|
LastSuccess: addr.LastSuccess,
|
|
})
|
|
}
|
|
sort.Sort(of)
|
|
return of
|
|
}
|
|
|
|
// crawlPeers will crawl the network looking for new peer addresses. (once)
|
|
func (r *PEXReactor) crawlPeers() {
|
|
peerInfos := r.getPeersToCrawl()
|
|
|
|
now := time.Now()
|
|
// Use addresses we know of to reach additional peers
|
|
for _, pi := range peerInfos {
|
|
// Do not attempt to connect with peers we recently dialed
|
|
if now.Sub(pi.LastAttempt) < defaultCrawlPeerInterval {
|
|
continue
|
|
}
|
|
// Otherwise, attempt to connect with the known address
|
|
_, err := r.Switch.DialPeerWithAddress(pi.Addr, false)
|
|
if err != nil {
|
|
r.book.MarkAttempt(pi.Addr)
|
|
continue
|
|
}
|
|
}
|
|
// Crawl the connected peers asking for more addresses
|
|
for _, pi := range peerInfos {
|
|
// We will wait a minimum period of time before crawling peers again
|
|
if now.Sub(pi.LastAttempt) >= defaultCrawlPeerInterval {
|
|
peer := r.Switch.Peers().Get(pi.Addr.ID)
|
|
if peer != nil {
|
|
r.RequestAddrs(peer)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// attemptDisconnects checks if we've been with each peer long enough to disconnect
|
|
func (r *PEXReactor) attemptDisconnects() {
|
|
for _, peer := range r.Switch.Peers().List() {
|
|
status := peer.Status()
|
|
if status.Duration < defaultSeedDisconnectWaitPeriod {
|
|
continue
|
|
}
|
|
if peer.IsPersistent() {
|
|
continue
|
|
}
|
|
r.Switch.StopPeerGracefully(peer)
|
|
}
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// 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)
|
|
}
|