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tendermint/p2p/switch.go

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package p2p
import (
"fmt"
"math"
"sync"
"time"
"github.com/tendermint/tendermint/config"
cmn "github.com/tendermint/tendermint/libs/common"
"github.com/tendermint/tendermint/p2p/conn"
)
const (
// wait a random amount of time from this interval
// before dialing peers or reconnecting to help prevent DoS
dialRandomizerIntervalMilliseconds = 3000
// repeatedly try to reconnect for a few minutes
// ie. 5 * 20 = 100s
reconnectAttempts = 20
reconnectInterval = 5 * time.Second
// then move into exponential backoff mode for ~1day
// ie. 3**10 = 16hrs
reconnectBackOffAttempts = 10
reconnectBackOffBaseSeconds = 3
)
//-----------------------------------------------------------------------------
// An AddrBook represents an address book from the pex package, which is used
// to store peer addresses.
type AddrBook interface {
AddAddress(addr *NetAddress, src *NetAddress) error
AddOurAddress(*NetAddress)
OurAddress(*NetAddress) bool
MarkGood(*NetAddress)
RemoveAddress(*NetAddress)
HasAddress(*NetAddress) bool
Save()
}
// PeerFilterFunc to be implemented by filter hooks after a new Peer has been
// fully setup.
type PeerFilterFunc func(IPeerSet, Peer) error
//-----------------------------------------------------------------------------
// Switch handles peer connections and exposes an API to receive incoming messages
// on `Reactors`. Each `Reactor` is responsible for handling incoming messages of one
// or more `Channels`. So while sending outgoing messages is typically performed on the peer,
// incoming messages are received on the reactor.
type Switch struct {
cmn.BaseService
config *config.P2PConfig
reactors map[string]Reactor
chDescs []*conn.ChannelDescriptor
reactorsByCh map[byte]Reactor
peers *PeerSet
dialing *cmn.CMap
reconnecting *cmn.CMap
nodeInfo NodeInfo // our node info
nodeKey *NodeKey // our node privkey
addrBook AddrBook
transport Transport
filterTimeout time.Duration
peerFilters []PeerFilterFunc
mConfig conn.MConnConfig
rng *cmn.Rand // seed for randomizing dial times and orders
metrics *Metrics
}
// SwitchOption sets an optional parameter on the Switch.
type SwitchOption func(*Switch)
// NewSwitch creates a new Switch with the given config.
func NewSwitch(
cfg *config.P2PConfig,
transport Transport,
options ...SwitchOption,
) *Switch {
sw := &Switch{
config: cfg,
reactors: make(map[string]Reactor),
chDescs: make([]*conn.ChannelDescriptor, 0),
reactorsByCh: make(map[byte]Reactor),
peers: NewPeerSet(),
dialing: cmn.NewCMap(),
reconnecting: cmn.NewCMap(),
metrics: NopMetrics(),
transport: transport,
filterTimeout: defaultFilterTimeout,
}
// Ensure we have a completely undeterministic PRNG.
sw.rng = cmn.NewRand()
mConfig := conn.DefaultMConnConfig()
mConfig.FlushThrottle = cfg.FlushThrottleTimeout
mConfig.SendRate = cfg.SendRate
mConfig.RecvRate = cfg.RecvRate
mConfig.MaxPacketMsgPayloadSize = cfg.MaxPacketMsgPayloadSize
sw.mConfig = mConfig
sw.BaseService = *cmn.NewBaseService(nil, "P2P Switch", sw)
for _, option := range options {
option(sw)
}
return sw
}
// SwitchFilterTimeout sets the timeout used for peer filters.
func SwitchFilterTimeout(timeout time.Duration) SwitchOption {
return func(sw *Switch) { sw.filterTimeout = timeout }
}
// SwitchPeerFilters sets the filters for rejection of new peers.
func SwitchPeerFilters(filters ...PeerFilterFunc) SwitchOption {
return func(sw *Switch) { sw.peerFilters = filters }
}
// WithMetrics sets the metrics.
func WithMetrics(metrics *Metrics) SwitchOption {
return func(sw *Switch) { sw.metrics = metrics }
}
//---------------------------------------------------------------------
// Switch setup
// AddReactor adds the given reactor to the switch.
// NOTE: Not goroutine safe.
func (sw *Switch) AddReactor(name string, reactor Reactor) Reactor {
// Validate the reactor.
// No two reactors can share the same channel.
reactorChannels := reactor.GetChannels()
for _, chDesc := range reactorChannels {
chID := chDesc.ID
if sw.reactorsByCh[chID] != nil {
cmn.PanicSanity(fmt.Sprintf("Channel %X has multiple reactors %v & %v", chID, sw.reactorsByCh[chID], reactor))
}
sw.chDescs = append(sw.chDescs, chDesc)
sw.reactorsByCh[chID] = reactor
}
sw.reactors[name] = reactor
reactor.SetSwitch(sw)
return reactor
}
// Reactors returns a map of reactors registered on the switch.
// NOTE: Not goroutine safe.
func (sw *Switch) Reactors() map[string]Reactor {
return sw.reactors
}
// Reactor returns the reactor with the given name.
// NOTE: Not goroutine safe.
func (sw *Switch) Reactor(name string) Reactor {
return sw.reactors[name]
}
// SetNodeInfo sets the switch's NodeInfo for checking compatibility and handshaking with other nodes.
// NOTE: Not goroutine safe.
func (sw *Switch) SetNodeInfo(nodeInfo NodeInfo) {
sw.nodeInfo = nodeInfo
}
// NodeInfo returns the switch's NodeInfo.
// NOTE: Not goroutine safe.
func (sw *Switch) NodeInfo() NodeInfo {
return sw.nodeInfo
}
// SetNodeKey sets the switch's private key for authenticated encryption.
// NOTE: Not goroutine safe.
func (sw *Switch) SetNodeKey(nodeKey *NodeKey) {
sw.nodeKey = nodeKey
}
//---------------------------------------------------------------------
// Service start/stop
// OnStart implements BaseService. It starts all the reactors and peers.
func (sw *Switch) OnStart() error {
// Start reactors
for _, reactor := range sw.reactors {
err := reactor.Start()
if err != nil {
return cmn.ErrorWrap(err, "failed to start %v", reactor)
}
}
// Start accepting Peers.
go sw.acceptRoutine()
return nil
}
// OnStop implements BaseService. It stops all peers and reactors.
func (sw *Switch) OnStop() {
// Stop peers
for _, p := range sw.peers.List() {
p.Stop()
sw.peers.Remove(p)
}
// Stop reactors
sw.Logger.Debug("Switch: Stopping reactors")
for _, reactor := range sw.reactors {
reactor.Stop()
}
}
//---------------------------------------------------------------------
// Peers
// Broadcast runs a go routine for each attempted send, which will block trying
// to send for defaultSendTimeoutSeconds. Returns a channel which receives
// success values for each attempted send (false if times out). Channel will be
// closed once msg bytes are sent to all peers (or time out).
//
// NOTE: Broadcast uses goroutines, so order of broadcast may not be preserved.
func (sw *Switch) Broadcast(chID byte, msgBytes []byte) chan bool {
successChan := make(chan bool, len(sw.peers.List()))
sw.Logger.Debug("Broadcast", "channel", chID, "msgBytes", fmt.Sprintf("%X", msgBytes))
var wg sync.WaitGroup
for _, peer := range sw.peers.List() {
wg.Add(1)
go func(peer Peer) {
defer wg.Done()
success := peer.Send(chID, msgBytes)
successChan <- success
}(peer)
}
go func() {
wg.Wait()
close(successChan)
}()
return successChan
}
// NumPeers returns the count of outbound/inbound and outbound-dialing peers.
func (sw *Switch) NumPeers() (outbound, inbound, dialing int) {
peers := sw.peers.List()
for _, peer := range peers {
if peer.IsOutbound() {
outbound++
} else {
inbound++
}
}
dialing = sw.dialing.Size()
return
}
// MaxNumOutboundPeers returns a maximum number of outbound peers.
func (sw *Switch) MaxNumOutboundPeers() int {
return sw.config.MaxNumOutboundPeers
}
// Peers returns the set of peers that are connected to the switch.
func (sw *Switch) Peers() IPeerSet {
return sw.peers
}
// StopPeerForError disconnects from a peer due to external error.
// If the peer is persistent, it will attempt to reconnect.
// TODO: make record depending on reason.
func (sw *Switch) StopPeerForError(peer Peer, reason interface{}) {
sw.Logger.Error("Stopping peer for error", "peer", peer, "err", reason)
sw.stopAndRemovePeer(peer, reason)
if peer.IsPersistent() {
addr := peer.OriginalAddr()
if addr == nil {
// FIXME: persistent peers can't be inbound right now.
// self-reported address for inbound persistent peers
addr = peer.NodeInfo().NetAddress()
}
go sw.reconnectToPeer(addr)
}
}
// StopPeerGracefully disconnects from a peer gracefully.
// TODO: handle graceful disconnects.
func (sw *Switch) StopPeerGracefully(peer Peer) {
sw.Logger.Info("Stopping peer gracefully")
sw.stopAndRemovePeer(peer, nil)
}
func (sw *Switch) stopAndRemovePeer(peer Peer, reason interface{}) {
sw.peers.Remove(peer)
sw.metrics.Peers.Add(float64(-1))
peer.Stop()
for _, reactor := range sw.reactors {
reactor.RemovePeer(peer, reason)
}
}
// reconnectToPeer tries to reconnect to the addr, first repeatedly
// with a fixed interval, then with exponential backoff.
// If no success after all that, it stops trying, and leaves it
// to the PEX/Addrbook to find the peer with the addr again
// NOTE: this will keep trying even if the handshake or auth fails.
// TODO: be more explicit with error types so we only retry on certain failures
// - ie. if we're getting ErrDuplicatePeer we can stop
// because the addrbook got us the peer back already
func (sw *Switch) reconnectToPeer(addr *NetAddress) {
if sw.reconnecting.Has(string(addr.ID)) {
return
}
sw.reconnecting.Set(string(addr.ID), addr)
defer sw.reconnecting.Delete(string(addr.ID))
start := time.Now()
sw.Logger.Info("Reconnecting to peer", "addr", addr)
for i := 0; i < reconnectAttempts; i++ {
if !sw.IsRunning() {
return
}
if sw.IsDialingOrExistingAddress(addr) {
sw.Logger.Debug("Peer connection has been established or dialed while we waiting next try", "addr", addr)
return
}
err := sw.DialPeerWithAddress(addr, true)
if err == nil {
return // success
}
sw.Logger.Info("Error reconnecting to peer. Trying again", "tries", i, "err", err, "addr", addr)
// sleep a set amount
sw.randomSleep(reconnectInterval)
continue
}
sw.Logger.Error("Failed to reconnect to peer. Beginning exponential backoff",
"addr", addr, "elapsed", time.Since(start))
for i := 0; i < reconnectBackOffAttempts; i++ {
if !sw.IsRunning() {
return
}
// sleep an exponentially increasing amount
sleepIntervalSeconds := math.Pow(reconnectBackOffBaseSeconds, float64(i))
sw.randomSleep(time.Duration(sleepIntervalSeconds) * time.Second)
err := sw.DialPeerWithAddress(addr, true)
if err == nil {
return // success
}
sw.Logger.Info("Error reconnecting to peer. Trying again", "tries", i, "err", err, "addr", addr)
}
sw.Logger.Error("Failed to reconnect to peer. Giving up", "addr", addr, "elapsed", time.Since(start))
}
// SetAddrBook allows to set address book on Switch.
func (sw *Switch) SetAddrBook(addrBook AddrBook) {
sw.addrBook = addrBook
}
// MarkPeerAsGood marks the given peer as good when it did something useful
// like contributed to consensus.
func (sw *Switch) MarkPeerAsGood(peer Peer) {
if sw.addrBook != nil {
sw.addrBook.MarkGood(peer.NodeInfo().NetAddress())
}
}
//---------------------------------------------------------------------
// Dialing
// DialPeersAsync dials a list of peers asynchronously in random order (optionally, making them persistent).
// Used to dial peers from config on startup or from unsafe-RPC (trusted sources).
// TODO: remove addrBook arg since it's now set on the switch
func (sw *Switch) DialPeersAsync(addrBook AddrBook, peers []string, persistent bool) error {
netAddrs, errs := NewNetAddressStrings(peers)
// only log errors, dial correct addresses
for _, err := range errs {
sw.Logger.Error("Error in peer's address", "err", err)
}
ourAddr := sw.nodeInfo.NetAddress()
// TODO: this code feels like it's in the wrong place.
// The integration tests depend on the addrBook being saved
// right away but maybe we can change that. Recall that
// the addrBook is only written to disk every 2min
if addrBook != nil {
// add peers to `addrBook`
for _, netAddr := range netAddrs {
// do not add our address or ID
if !netAddr.Same(ourAddr) {
if err := addrBook.AddAddress(netAddr, ourAddr); err != nil {
sw.Logger.Error("Can't add peer's address to addrbook", "err", err)
}
}
}
// Persist some peers to disk right away.
// NOTE: integration tests depend on this
addrBook.Save()
}
// permute the list, dial them in random order.
perm := sw.rng.Perm(len(netAddrs))
for i := 0; i < len(perm); i++ {
go func(i int) {
j := perm[i]
addr := netAddrs[j]
if addr.Same(ourAddr) {
sw.Logger.Debug("Ignore attempt to connect to ourselves", "addr", addr, "ourAddr", ourAddr)
return
}
sw.randomSleep(0)
if sw.IsDialingOrExistingAddress(addr) {
sw.Logger.Debug("Ignore attempt to connect to an existing peer", "addr", addr)
return
}
err := sw.DialPeerWithAddress(addr, persistent)
if err != nil {
switch err.(type) {
case ErrSwitchConnectToSelf, ErrSwitchDuplicatePeerID:
sw.Logger.Debug("Error dialing peer", "err", err)
default:
sw.Logger.Error("Error dialing peer", "err", err)
}
}
}(i)
}
return nil
}
// DialPeerWithAddress dials the given peer and runs sw.addPeer if it connects and authenticates successfully.
// If `persistent == true`, the switch will always try to reconnect to this peer if the connection ever fails.
func (sw *Switch) DialPeerWithAddress(addr *NetAddress, persistent bool) error {
sw.dialing.Set(string(addr.ID), addr)
defer sw.dialing.Delete(string(addr.ID))
return sw.addOutboundPeerWithConfig(addr, sw.config, persistent)
}
// sleep for interval plus some random amount of ms on [0, dialRandomizerIntervalMilliseconds]
func (sw *Switch) randomSleep(interval time.Duration) {
r := time.Duration(sw.rng.Int63n(dialRandomizerIntervalMilliseconds)) * time.Millisecond
time.Sleep(r + interval)
}
// IsDialingOrExistingAddress returns true if switch has a peer with the given
// address or dialing it at the moment.
func (sw *Switch) IsDialingOrExistingAddress(addr *NetAddress) bool {
return sw.dialing.Has(string(addr.ID)) ||
sw.peers.Has(addr.ID) ||
(!sw.config.AllowDuplicateIP && sw.peers.HasIP(addr.IP))
}
func (sw *Switch) acceptRoutine() {
for {
p, err := sw.transport.Accept(peerConfig{
chDescs: sw.chDescs,
onPeerError: sw.StopPeerForError,
reactorsByCh: sw.reactorsByCh,
metrics: sw.metrics,
})
if err != nil {
switch err.(type) {
case ErrRejected:
rErr := err.(ErrRejected)
if rErr.IsSelf() {
// Remove the given address from the address book and add to our addresses
// to avoid dialing in the future.
addr := rErr.Addr()
sw.addrBook.RemoveAddress(&addr)
sw.addrBook.AddOurAddress(&addr)
}
sw.Logger.Info(
"Inbound Peer rejected",
"err", err,
"numPeers", sw.peers.Size(),
)
continue
case *ErrTransportClosed:
sw.Logger.Error(
"Stopped accept routine, as transport is closed",
"numPeers", sw.peers.Size(),
)
default:
sw.Logger.Error(
"Accept on transport errored",
"err", err,
"numPeers", sw.peers.Size(),
)
}
break
}
// Ignore connection if we already have enough peers.
_, in, _ := sw.NumPeers()
if in >= sw.config.MaxNumInboundPeers {
sw.Logger.Info(
"Ignoring inbound connection: already have enough inbound peers",
"address", p.NodeInfo().NetAddress().String(),
"have", in,
"max", sw.config.MaxNumInboundPeers,
)
_ = p.Stop()
continue
}
if err := sw.addPeer(p); err != nil {
_ = p.Stop()
sw.Logger.Info(
"Ignoring inbound connection: error while adding peer",
"err", err,
"id", p.ID(),
)
}
}
}
// dial the peer; make secret connection; authenticate against the dialed ID;
// add the peer.
// if dialing fails, start the reconnect loop. If handhsake fails, its over.
// If peer is started succesffuly, reconnectLoop will start when
// StopPeerForError is called
func (sw *Switch) addOutboundPeerWithConfig(
addr *NetAddress,
cfg *config.P2PConfig,
persistent bool,
) error {
sw.Logger.Info("Dialing peer", "address", addr)
// XXX(xla): Remove the leakage of test concerns in implementation.
if cfg.TestDialFail {
go sw.reconnectToPeer(addr)
return fmt.Errorf("dial err (peerConfig.DialFail == true)")
}
p, err := sw.transport.Dial(*addr, peerConfig{
chDescs: sw.chDescs,
onPeerError: sw.StopPeerForError,
persistent: persistent,
reactorsByCh: sw.reactorsByCh,
metrics: sw.metrics,
})
if err != nil {
switch e := err.(type) {
case ErrRejected:
if e.IsSelf() {
// Remove the given address from the address book and add to our addresses
// to avoid dialing in the future.
sw.addrBook.RemoveAddress(addr)
sw.addrBook.AddOurAddress(addr)
return err
}
}
// retry persistent peers after
// any dial error besides IsSelf()
if persistent {
go sw.reconnectToPeer(addr)
}
return err
}
if err := sw.addPeer(p); err != nil {
_ = p.Stop()
return err
}
return nil
}
func (sw *Switch) filterPeer(p Peer) error {
// Avoid duplicate
if sw.peers.Has(p.ID()) {
return ErrRejected{id: p.ID(), isDuplicate: true}
}
errc := make(chan error, len(sw.peerFilters))
for _, f := range sw.peerFilters {
go func(f PeerFilterFunc, p Peer, errc chan<- error) {
errc <- f(sw.peers, p)
}(f, p, errc)
}
for i := 0; i < cap(errc); i++ {
select {
case err := <-errc:
if err != nil {
return ErrRejected{id: p.ID(), err: err, isFiltered: true}
}
case <-time.After(sw.filterTimeout):
return ErrFilterTimeout{}
}
}
return nil
}
// addPeer starts up the Peer and adds it to the Switch.
func (sw *Switch) addPeer(p Peer) error {
if err := sw.filterPeer(p); err != nil {
return err
}
p.SetLogger(sw.Logger.With("peer", p.NodeInfo().NetAddress()))
// All good. Start peer
if sw.IsRunning() {
if err := sw.startInitPeer(p); err != nil {
return err
}
}
// Add the peer to .peers.
// We start it first so that a peer in the list is safe to Stop.
// It should not err since we already checked peers.Has().
if err := sw.peers.Add(p); err != nil {
return err
}
sw.Logger.Info("Added peer", "peer", p)
sw.metrics.Peers.Add(float64(1))
return nil
}
func (sw *Switch) startInitPeer(p Peer) error {
err := p.Start() // spawn send/recv routines
if err != nil {
// Should never happen
sw.Logger.Error(
"Error starting peer",
"err", err,
"peer", p,
)
return err
}
for _, reactor := range sw.reactors {
reactor.AddPeer(p)
}
return nil
}