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tendermint/p2p/switch.go

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package p2p
import (
"fmt"
"math"
"net"
"sync"
"time"
cfg "github.com/tendermint/tendermint/config"
"github.com/tendermint/tendermint/p2p/conn"
cmn "github.com/tendermint/tmlibs/common"
)
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
// keep at least this many outbound peers
// TODO: move to config
DefaultMinNumOutboundPeers = 10
)
//-----------------------------------------------------------------------------
// 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()
}
//-----------------------------------------------------------------------------
// 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 *cfg.P2PConfig
peerConfig *PeerConfig
listeners []Listener
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
filterConnByAddr func(net.Addr) error
filterConnByID func(ID) error
rng *cmn.Rand // seed for randomizing dial times and orders
}
// NewSwitch creates a new Switch with the given config.
func NewSwitch(config *cfg.P2PConfig) *Switch {
sw := &Switch{
config: config,
peerConfig: DefaultPeerConfig(),
reactors: make(map[string]Reactor),
chDescs: make([]*conn.ChannelDescriptor, 0),
reactorsByCh: make(map[byte]Reactor),
peers: NewPeerSet(),
dialing: cmn.NewCMap(),
reconnecting: cmn.NewCMap(),
}
// Ensure we have a completely undeterministic PRNG.
sw.rng = cmn.NewRand()
// TODO: collapse the peerConfig into the config ?
sw.peerConfig.MConfig.FlushThrottle = time.Duration(config.FlushThrottleTimeout) * time.Millisecond
sw.peerConfig.MConfig.SendRate = config.SendRate
sw.peerConfig.MConfig.RecvRate = config.RecvRate
sw.peerConfig.MConfig.MaxPacketMsgPayloadSize = config.MaxPacketMsgPayloadSize
sw.peerConfig.AuthEnc = config.AuthEnc
sw.BaseService = *cmn.NewBaseService(nil, "P2P Switch", sw)
return sw
}
//---------------------------------------------------------------------
// 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]
}
// AddListener adds the given listener to the switch for listening to incoming peer connections.
// NOTE: Not goroutine safe.
func (sw *Switch) AddListener(l Listener) {
sw.listeners = append(sw.listeners, l)
}
// Listeners returns the list of listeners the switch listens on.
// NOTE: Not goroutine safe.
func (sw *Switch) Listeners() []Listener {
return sw.listeners
}
// IsListening returns true if the switch has at least one listener.
// NOTE: Not goroutine safe.
func (sw *Switch) IsListening() bool {
return len(sw.listeners) > 0
}
// 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, peers, and listeners.
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 listeners
for _, listener := range sw.listeners {
go sw.listenerRoutine(listener)
}
return nil
}
// OnStop implements BaseService. It stops all listeners, peers, and reactors.
func (sw *Switch) OnStop() {
// Stop listeners
for _, listener := range sw.listeners {
listener.Stop()
}
sw.listeners = nil
// Stop peers
for _, peer := range sw.peers.List() {
peer.Stop()
sw.peers.Remove(peer)
}
// 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
}
// 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() {
// NOTE: this is the self-reported addr, not the original we dialed
go sw.reconnectToPeer(peer.NodeInfo().NetAddress())
}
}
// 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)
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
}
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
// IsDialing returns true if the switch is currently dialing the given ID.
func (sw *Switch) IsDialing(id ID) bool {
return sw.dialing.Has(string(id))
}
// 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]
// do not dial ourselves
if addr.Same(ourAddr) {
return
}
sw.randomSleep(0)
err := sw.DialPeerWithAddress(addr, persistent)
if err != nil {
switch err {
case ErrSwitchConnectToSelf, ErrSwitchDuplicatePeer:
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.peerConfig, 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)
}
//------------------------------------------------------------------------------------
// Connection filtering
// FilterConnByAddr returns an error if connecting to the given address is forbidden.
func (sw *Switch) FilterConnByAddr(addr net.Addr) error {
if sw.filterConnByAddr != nil {
return sw.filterConnByAddr(addr)
}
return nil
}
// FilterConnByID returns an error if connecting to the given peer ID is forbidden.
func (sw *Switch) FilterConnByID(id ID) error {
if sw.filterConnByID != nil {
return sw.filterConnByID(id)
}
return nil
}
// SetAddrFilter sets the function for filtering connections by address.
func (sw *Switch) SetAddrFilter(f func(net.Addr) error) {
sw.filterConnByAddr = f
}
// SetIDFilter sets the function for filtering connections by peer ID.
func (sw *Switch) SetIDFilter(f func(ID) error) {
sw.filterConnByID = f
}
//------------------------------------------------------------------------------------
func (sw *Switch) listenerRoutine(l Listener) {
for {
inConn, ok := <-l.Connections()
if !ok {
break
}
// ignore connection if we already have enough
// leave room for MinNumOutboundPeers
maxPeers := sw.config.MaxNumPeers - DefaultMinNumOutboundPeers
if maxPeers <= sw.peers.Size() {
sw.Logger.Info("Ignoring inbound connection: already have enough peers", "address", inConn.RemoteAddr().String(), "numPeers", sw.peers.Size(), "max", maxPeers)
continue
}
// New inbound connection!
err := sw.addInboundPeerWithConfig(inConn, sw.peerConfig)
if err != nil {
sw.Logger.Info("Ignoring inbound connection: error while adding peer", "address", inConn.RemoteAddr().String(), "err", err)
continue
}
}
// cleanup
}
func (sw *Switch) addInboundPeerWithConfig(conn net.Conn, config *PeerConfig) error {
peerConn, err := newInboundPeerConn(conn, config, sw.nodeKey.PrivKey)
if err != nil {
conn.Close() // peer is nil
return err
}
if err = sw.addPeer(peerConn); err != nil {
peerConn.CloseConn()
return err
}
return nil
}
// 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, config *PeerConfig, persistent bool) error {
sw.Logger.Info("Dialing peer", "address", addr)
peerConn, err := newOutboundPeerConn(addr, config, persistent, sw.nodeKey.PrivKey)
if err != nil {
if persistent {
go sw.reconnectToPeer(addr)
}
return err
}
if err := sw.addPeer(peerConn); err != nil {
peerConn.CloseConn()
return err
}
return nil
}
// addPeer performs the Tendermint P2P handshake with a peer
// that already has a SecretConnection. If all goes well,
// it starts the peer and adds it to the switch.
// NOTE: This performs a blocking handshake before the peer is added.
// NOTE: If error is returned, caller is responsible for calling peer.CloseConn()
func (sw *Switch) addPeer(pc peerConn) error {
addr := pc.conn.RemoteAddr()
if err := sw.FilterConnByAddr(addr); err != nil {
return err
}
// NOTE: if AuthEnc==false, we don't have a peerID until after the handshake.
// If AuthEnc==true then we already know the ID and could do the checks first before the handshake,
// but it's simple to just deal with both cases the same after the handshake.
// Exchange NodeInfo on the conn
peerNodeInfo, err := pc.HandshakeTimeout(sw.nodeInfo, time.Duration(sw.peerConfig.HandshakeTimeout*time.Second))
if err != nil {
return err
}
peerID := peerNodeInfo.ID
// ensure connection key matches self reported key
if pc.config.AuthEnc {
connID := pc.ID()
if peerID != connID {
return fmt.Errorf("nodeInfo.ID() (%v) doesn't match conn.ID() (%v)",
peerID, connID)
}
}
// Validate the peers nodeInfo
if err := peerNodeInfo.Validate(); err != nil {
return err
}
// Avoid self
if sw.nodeKey.ID() == peerID {
addr := peerNodeInfo.NetAddress()
// remove the given address from the address book if we added it earlier
sw.addrBook.RemoveAddress(addr)
// add the given address to the address book to avoid dialing ourselves
// again this is our public address
sw.addrBook.AddOurAddress(addr)
return ErrSwitchConnectToSelf
}
// Avoid duplicate
if sw.peers.Has(peerID) {
return ErrSwitchDuplicatePeer
}
// Filter peer against ID white list
if err := sw.FilterConnByID(peerID); err != nil {
return err
}
// Check version, chain id
if err := sw.nodeInfo.CompatibleWith(peerNodeInfo); err != nil {
return err
}
peer := newPeer(pc, peerNodeInfo, sw.reactorsByCh, sw.chDescs, sw.StopPeerForError)
peer.SetLogger(sw.Logger.With("peer", addr))
peer.Logger.Info("Successful handshake with peer", "peerNodeInfo", peerNodeInfo)
// All good. Start peer
if sw.IsRunning() {
if err = sw.startInitPeer(peer); 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(peer); err != nil {
return err
}
sw.Logger.Info("Added peer", "peer", peer)
return nil
}
func (sw *Switch) startInitPeer(peer *peer) error {
err := peer.Start() // spawn send/recv routines
if err != nil {
// Should never happen
sw.Logger.Error("Error starting peer", "peer", peer, "err", err)
return err
}
for _, reactor := range sw.reactors {
reactor.AddPeer(peer)
}
return nil
}