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tendermint/p2p/peer.go

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package p2p
import (
"context"
"errors"
"fmt"
"io"
"math"
"math/rand"
"net"
"runtime/debug"
"sort"
"sync"
"time"
"github.com/gogo/protobuf/proto"
"github.com/google/orderedcode"
dbm "github.com/tendermint/tm-db"
"github.com/tendermint/tendermint/libs/cmap"
"github.com/tendermint/tendermint/libs/log"
"github.com/tendermint/tendermint/libs/service"
tmconn "github.com/tendermint/tendermint/p2p/conn"
p2pproto "github.com/tendermint/tendermint/proto/tendermint/p2p"
)
// PeerStatus specifies peer statuses.
type PeerStatus string
const (
PeerStatusNew = PeerStatus("new") // New peer which we haven't tried to contact yet.
PeerStatusUp = PeerStatus("up") // Peer which we have an active connection to.
PeerStatusDown = PeerStatus("down") // Peer which we're temporarily disconnected from.
PeerStatusRemoved = PeerStatus("removed") // Peer which has been removed.
PeerStatusBanned = PeerStatus("banned") // Peer which is banned for misbehavior.
)
// PeerError is a peer error reported by a reactor via the Error channel. The
// severity may cause the peer to be disconnected or banned depending on policy.
type PeerError struct {
PeerID NodeID
Err error
Severity PeerErrorSeverity
}
// PeerErrorSeverity determines the severity of a peer error.
type PeerErrorSeverity string
const (
PeerErrorSeverityLow PeerErrorSeverity = "low" // Mostly ignored.
PeerErrorSeverityHigh PeerErrorSeverity = "high" // May disconnect.
PeerErrorSeverityCritical PeerErrorSeverity = "critical" // Ban.
)
// PeerUpdatesCh defines a wrapper around a PeerUpdate go channel that allows
// a reactor to listen for peer updates and safely close it when stopping.
type PeerUpdatesCh struct {
closeOnce sync.Once
// updatesCh defines the go channel in which the router sends peer updates to
// reactors. Each reactor will have its own PeerUpdatesCh to listen for updates
// from.
updatesCh chan PeerUpdate
// doneCh is used to signal that a PeerUpdatesCh is closed. It is the
// reactor's responsibility to invoke Close.
doneCh chan struct{}
}
// NewPeerUpdates returns a reference to a new PeerUpdatesCh.
func NewPeerUpdates(updatesCh chan PeerUpdate) *PeerUpdatesCh {
return &PeerUpdatesCh{
updatesCh: updatesCh,
doneCh: make(chan struct{}),
}
}
// Updates returns a read-only go channel where a consuming reactor can listen
// for peer updates sent from the router.
func (puc *PeerUpdatesCh) Updates() <-chan PeerUpdate {
return puc.updatesCh
}
// Close closes the PeerUpdatesCh channel. It should only be closed by the respective
// reactor when stopping and ensure nothing is listening for updates.
//
// NOTE: After a PeerUpdatesCh is closed, the router may safely assume it can no
// longer send on the internal updatesCh, however it should NEVER explicitly close
// it as that could result in panics by sending on a closed channel.
func (puc *PeerUpdatesCh) Close() {
puc.closeOnce.Do(func() {
close(puc.doneCh)
})
}
// Done returns a read-only version of the PeerUpdatesCh's internal doneCh go
// channel that should be used by a router to signal when it is safe to explicitly
// not send any peer updates.
func (puc *PeerUpdatesCh) Done() <-chan struct{} {
return puc.doneCh
}
// PeerUpdate is a peer status update for reactors.
type PeerUpdate struct {
PeerID NodeID
Status PeerStatus
}
// PeerScore is a numeric score assigned to a peer (higher is better).
type PeerScore uint16
const (
// PeerScorePersistent is added for persistent peers.
PeerScorePersistent PeerScore = 100
)
// PeerManager manages peer lifecycle information, using a peerStore for
// underlying storage. Its primary purpose is to determine which peers to
// connect to next, make sure a peer only has a single active connection (either
// inbound or outbound), and evict peers to make room for higher-scored peers.
// It does not manage actual connections (this is handled by the Router),
// only the peer lifecycle state.
//
// We track dialing and connected states independently. This allows us to accept
// an inbound connection from a peer while the router is also dialing an
// outbound connection to that same peer, which will cause the dialer to
// eventually error when attempting to mark the peer as connected. This also
// avoids race conditions where multiple goroutines may end up dialing a peer if
// an incoming connection was briefly accepted and disconnected while we were
// also dialing.
//
// For an outbound connection, the flow is as follows:
// - DialNext: returns a peer address to dial, marking the peer as dialing.
// - DialFailed: reports a dial failure, unmarking the peer as dialing.
// - Dialed: successfully dialed, unmarking as dialing and marking as connected
// (or erroring if already connected).
// - Ready: routing is up, broadcasts a PeerStatusUp peer update to subscribers.
// - Disconnected: peer disconnects, unmarking as connected and broadcasts a
// PeerStatusDown peer update.
//
// For an inbound connection, the flow is as follows:
// - Accepted: successfully accepted connection, marking as connected (or erroring
// if already connected).
// - Ready: routing is up, broadcasts a PeerStatusUp peer update to subscribers.
// - Disconnected: peer disconnects, unmarking as connected and broadcasts a
// PeerStatusDown peer update.
//
// When evicting peers, either because peers are explicitly scheduled for
// eviction or we are connected to too many peers, the flow is as follows:
// - EvictNext: if marked evict and connected, unmark evict and mark evicting.
// If beyond MaxConnected, pick lowest-scored peer and mark evicting.
// - Disconnected: unmark connected, evicting, evict, and broadcast a
// PeerStatusDown peer update.
//
// If all connection slots are full (at MaxConnections), we can use up to
// MaxConnectionsUpgrade additional connections to probe any higher-scored
// unconnected peers, and if we reach them (or they reach us) we allow the
// connection and evict a lower-scored peer. We mark the lower-scored peer as
// upgrading[from]=to to make sure no other higher-scored peers can claim the
// same one for an upgrade. The flow is as follows:
// - Accepted: if upgrade is possible, mark connected and add lower-scored to evict.
// - DialNext: if upgrade is possible, mark upgrading[from]=to and dialing.
// - DialFailed: unmark upgrading[from]=to and dialing.
// - Dialed: unmark upgrading[from]=to and dialing, mark as connected, add
// lower-scored to evict.
// - EvictNext: pick peer from evict, mark as evicting.
// - Disconnected: unmark connected, upgrading[from]=to, evict, evicting.
//
// FIXME: The old stack supports ABCI-based peer ID filtering via
// /p2p/filter/id/<ID> queries, we should implement this here as well by taking
// a peer ID filtering callback in PeerManagerOptions and configuring it during
// Node setup.
type PeerManager struct {
options PeerManagerOptions
wakeDialCh chan struct{} // wakes up DialNext() on relevant peer changes
wakeEvictCh chan struct{} // wakes up EvictNext() on relevant peer changes
closeCh chan struct{} // signal channel for Close()
closeOnce sync.Once
mtx sync.Mutex
store *peerStore
dialing map[NodeID]bool // peers being dialed (DialNext -> Dialed/DialFail)
upgrading map[NodeID]NodeID // peers claimed for upgrade (DialNext -> Dialed/DialFail)
connected map[NodeID]bool // connected peers (Dialed/Accepted -> Disconnected)
evict map[NodeID]bool // peers scheduled for eviction (Connected -> EvictNext)
evicting map[NodeID]bool // peers being evicted (EvictNext -> Disconnected)
subscriptions map[*PeerUpdatesCh]*PeerUpdatesCh // keyed by struct identity (address)
}
// PeerManagerOptions specifies options for a PeerManager.
type PeerManagerOptions struct {
// PersistentPeers are peers that we want to maintain persistent connections
// to. These will be scored higher than other peers, and if
// MaxConnectedUpgrade is non-zero any lower-scored peers will be evicted if
// necessary to make room for these.
PersistentPeers []NodeID
// MaxPeers is the maximum number of peers to track information about, i.e.
// store in the peer store. When exceeded, the lowest-scored unconnected peers
// will be deleted. 0 means no limit.
MaxPeers uint16
// MaxConnected is the maximum number of connected peers (inbound and
// outbound). 0 means no limit.
MaxConnected uint16
// MaxConnectedUpgrade is the maximum number of additional connections to
// use for probing any better-scored peers to upgrade to when all connection
// slots are full. 0 disables peer upgrading.
//
// For example, if we are already connected to MaxConnected peers, but we
// know or learn about better-scored peers (e.g. configured persistent
// peers) that we are not connected too, then we can probe these peers by
// using up to MaxConnectedUpgrade connections, and once connected evict the
// lowest-scored connected peers. This also works for inbound connections,
// i.e. if a higher-scored peer attempts to connect to us, we can accept
// the connection and evict a lower-scored peer.
MaxConnectedUpgrade uint16
// MinRetryTime is the minimum time to wait between retries. Retry times
// double for each retry, up to MaxRetryTime. 0 disables retries.
MinRetryTime time.Duration
// MaxRetryTime is the maximum time to wait between retries. 0 means
// no maximum, in which case the retry time will keep doubling.
MaxRetryTime time.Duration
// MaxRetryTimePersistent is the maximum time to wait between retries for
// peers listed in PersistentPeers. 0 uses MaxRetryTime instead.
MaxRetryTimePersistent time.Duration
// RetryTimeJitter is the upper bound of a random interval added to
// retry times, to avoid thundering herds. 0 disables jutter.
RetryTimeJitter time.Duration
}
// NewPeerManager creates a new peer manager.
func NewPeerManager(peerDB dbm.DB, options PeerManagerOptions) (*PeerManager, error) {
store, err := newPeerStore(peerDB)
if err != nil {
return nil, err
}
peerManager := &PeerManager{
options: options,
closeCh: make(chan struct{}),
// We use a buffer of size 1 for these trigger channels, with
// non-blocking sends. This ensures that if e.g. wakeDial() is called
// multiple times before the initial trigger is picked up we only
// process the trigger once.
//
// FIXME: This should maybe be a libs/sync type.
wakeDialCh: make(chan struct{}, 1),
wakeEvictCh: make(chan struct{}, 1),
store: store,
dialing: map[NodeID]bool{},
upgrading: map[NodeID]NodeID{},
connected: map[NodeID]bool{},
evict: map[NodeID]bool{},
evicting: map[NodeID]bool{},
subscriptions: map[*PeerUpdatesCh]*PeerUpdatesCh{},
}
if err = peerManager.configurePeers(); err != nil {
return nil, err
}
if err = peerManager.prunePeers(); err != nil {
return nil, err
}
return peerManager, nil
}
// configurePeers configures peers in the peer store with ephemeral runtime
// configuration, e.g. setting peerInfo.Persistent based on
// PeerManagerOptions.PersistentPeers. The caller must hold the mutex lock.
func (m *PeerManager) configurePeers() error {
for _, peerID := range m.options.PersistentPeers {
if peer, ok := m.store.Get(peerID); ok {
peer.Persistent = true
if err := m.store.Set(peer); err != nil {
return err
}
}
}
return nil
}
// prunePeers removes peers from the peer store if it contains more than
// MaxPeers peers. The lowest-scored non-connected peers are removed.
// The caller must hold the mutex lock.
func (m *PeerManager) prunePeers() error {
if m.options.MaxPeers == 0 || m.store.Size() <= int(m.options.MaxPeers) {
return nil
}
m.mtx.Lock()
defer m.mtx.Unlock()
ranked := m.store.Ranked()
for i := len(ranked) - 1; i >= 0; i-- {
peerID := ranked[i].ID
switch {
case m.store.Size() <= int(m.options.MaxPeers):
break
case m.dialing[peerID]:
case m.connected[peerID]:
case m.evicting[peerID]:
default:
if err := m.store.Delete(peerID); err != nil {
return err
}
}
}
return nil
}
// Close closes the peer manager, releasing resources allocated with it
// (specifically any running goroutines).
func (m *PeerManager) Close() {
m.closeOnce.Do(func() {
close(m.closeCh)
})
}
// Add adds a peer to the manager, given as an address. If the peer already
// exists, the address is added to it.
func (m *PeerManager) Add(address NodeAddress) error {
if err := address.Validate(); err != nil {
return err
}
m.mtx.Lock()
defer m.mtx.Unlock()
peer, ok := m.store.Get(address.NodeID)
if !ok {
peer = m.makePeerInfo(address.NodeID)
}
if _, ok := peer.AddressInfo[address.String()]; !ok {
peer.AddressInfo[address.String()] = &peerAddressInfo{Address: address}
}
if err := m.store.Set(peer); err != nil {
return err
}
if err := m.prunePeers(); err != nil {
return err
}
m.wakeDial()
return nil
}
// Advertise returns a list of peer addresses to advertise to a peer.
//
// FIXME: This is fairly naïve and only returns the addresses of the
// highest-ranked peers.
func (m *PeerManager) Advertise(peerID NodeID, limit uint16) []NodeAddress {
m.mtx.Lock()
defer m.mtx.Unlock()
addresses := make([]NodeAddress, 0, limit)
for _, peer := range m.store.Ranked() {
if peer.ID == peerID {
continue
}
for _, addressInfo := range peer.AddressInfo {
if len(addresses) >= int(limit) {
return addresses
}
addresses = append(addresses, addressInfo.Address)
}
}
return addresses
}
// makePeerInfo creates a peerInfo for a new peer.
func (m *PeerManager) makePeerInfo(id NodeID) peerInfo {
isPersistent := false
for _, p := range m.options.PersistentPeers {
if id == p {
isPersistent = true
break
}
}
return peerInfo{
ID: id,
Persistent: isPersistent,
AddressInfo: map[string]*peerAddressInfo{},
}
}
// Subscribe subscribes to peer updates. The caller must consume the peer
// updates in a timely fashion and close the subscription when done, since
// delivery is guaranteed and will block peer connection/disconnection
// otherwise.
func (m *PeerManager) Subscribe() *PeerUpdatesCh {
// FIXME: We may want to use a size 1 buffer here. When the router
// broadcasts a peer update it has to loop over all of the
// subscriptions, and we want to avoid blocking and waiting for a
// context switch before continuing to the next subscription. This also
// prevents tail latencies from compounding across updates. We also want
// to make sure the subscribers are reasonably in sync, so it should be
// kept at 1. However, this should be benchmarked first.
peerUpdates := NewPeerUpdates(make(chan PeerUpdate))
m.mtx.Lock()
m.subscriptions[peerUpdates] = peerUpdates
m.mtx.Unlock()
go func() {
<-peerUpdates.Done()
m.mtx.Lock()
delete(m.subscriptions, peerUpdates)
m.mtx.Unlock()
}()
return peerUpdates
}
// broadcast broadcasts a peer update to all subscriptions. The caller must
// already hold the mutex lock. This means the mutex is held for the duration
// of the broadcast, which we want to make sure all subscriptions receive all
// updates in the same order.
//
// FIXME: Consider using more fine-grained mutexes here, and/or a channel to
// enforce ordering of updates.
func (m *PeerManager) broadcast(peerUpdate PeerUpdate) {
for _, sub := range m.subscriptions {
select {
case sub.updatesCh <- peerUpdate:
case <-sub.doneCh:
}
}
}
// DialNext finds an appropriate peer address to dial, and marks it as dialing.
// If no peer is found, or all connection slots are full, it blocks until one
// becomes available. The caller must call Dialed() or DialFailed() for the
// returned peer. The context can be used to cancel the call.
func (m *PeerManager) DialNext(ctx context.Context) (NodeID, NodeAddress, error) {
for {
id, address, err := m.TryDialNext()
if err != nil || id != "" {
return id, address, err
}
select {
case <-m.wakeDialCh:
case <-ctx.Done():
return "", NodeAddress{}, ctx.Err()
}
}
}
// TryDialNext is equivalent to DialNext(), but immediately returns an empty
// peer ID if no peers or connection slots are available.
func (m *PeerManager) TryDialNext() (NodeID, NodeAddress, error) {
m.mtx.Lock()
defer m.mtx.Unlock()
// We allow dialing MaxConnected+MaxConnectedUpgrade peers. Including
// MaxConnectedUpgrade allows us to probe additional peers that have a
// higher score than any other peers, and if successful evict it.
if m.options.MaxConnected > 0 &&
len(m.connected)+len(m.dialing) >= int(m.options.MaxConnected)+int(m.options.MaxConnectedUpgrade) {
return "", NodeAddress{}, nil
}
for _, peer := range m.store.Ranked() {
if m.dialing[peer.ID] || m.connected[peer.ID] {
continue
}
for _, addressInfo := range peer.AddressInfo {
if time.Since(addressInfo.LastDialFailure) < m.retryDelay(addressInfo.DialFailures, peer.Persistent) {
continue
}
// We now have an eligible address to dial. If we're full but have
// upgrade capacity (as checked above), we find a lower-scored peer
// we can replace and mark it as upgrading so noone else claims it.
//
// If we don't find one, there is no point in trying additional
// peers, since they will all have the same or lower score than this
// peer (since they're ordered by score via peerStore.Ranked).
if m.options.MaxConnected > 0 && len(m.connected) >= int(m.options.MaxConnected) {
upgradeFromPeer := m.findUpgradeCandidate(peer.ID, peer.Score())
if upgradeFromPeer == "" {
return "", NodeAddress{}, nil
}
m.upgrading[upgradeFromPeer] = peer.ID
}
m.dialing[peer.ID] = true
return peer.ID, addressInfo.Address, nil
}
}
return "", NodeAddress{}, nil
}
// wakeDial is used to notify DialNext about changes that *may* cause new
// peers to become eligible for dialing, such as peer disconnections and
// retry timeouts.
func (m *PeerManager) wakeDial() {
// The channel has a 1-size buffer. A non-blocking send ensures
// we only queue up at most 1 trigger between each DialNext().
select {
case m.wakeDialCh <- struct{}{}:
default:
}
}
// wakeEvict is used to notify EvictNext about changes that *may* cause
// peers to become eligible for eviction, such as peer upgrades.
func (m *PeerManager) wakeEvict() {
// The channel has a 1-size buffer. A non-blocking send ensures
// we only queue up at most 1 trigger between each EvictNext().
select {
case m.wakeEvictCh <- struct{}{}:
default:
}
}
// retryDelay calculates a dial retry delay using exponential backoff, based on
// retry settings in PeerManagerOptions. If MinRetryTime is 0, this returns
// MaxInt64 (i.e. an infinite retry delay, effectively disabling retries).
func (m *PeerManager) retryDelay(failures uint32, persistent bool) time.Duration {
if failures == 0 {
return 0
}
if m.options.MinRetryTime == 0 {
return time.Duration(math.MaxInt64)
}
maxDelay := m.options.MaxRetryTime
if persistent && m.options.MaxRetryTimePersistent > 0 {
maxDelay = m.options.MaxRetryTimePersistent
}
delay := m.options.MinRetryTime * time.Duration(math.Pow(2, float64(failures)))
if maxDelay > 0 && delay > maxDelay {
delay = maxDelay
}
// FIXME: This should use a PeerManager-scoped RNG.
delay += time.Duration(rand.Int63n(int64(m.options.RetryTimeJitter))) // nolint:gosec
return delay
}
// DialFailed reports a failed dial attempt. This will make the peer available
// for dialing again when appropriate.
//
// FIXME: This should probably delete or mark bad addresses/peers after some time.
func (m *PeerManager) DialFailed(peerID NodeID, address NodeAddress) error {
m.mtx.Lock()
defer m.mtx.Unlock()
delete(m.dialing, peerID)
for from, to := range m.upgrading {
if to == peerID {
delete(m.upgrading, from) // Unmark failed upgrade attempt.
}
}
peer, ok := m.store.Get(peerID)
if !ok { // Peer may have been removed while dialing, ignore.
return nil
}
addressInfo, ok := peer.AddressInfo[address.String()]
if !ok {
return nil // Assume the address has been removed, ignore.
}
addressInfo.LastDialFailure = time.Now().UTC()
addressInfo.DialFailures++
if err := m.store.Set(peer); err != nil {
return err
}
// We spawn a goroutine that notifies DialNext() again when the retry
// timeout has elapsed, so that we can consider dialing it again.
go func() {
retryDelay := m.retryDelay(addressInfo.DialFailures, peer.Persistent)
if retryDelay == time.Duration(math.MaxInt64) {
return
}
// Use an explicit timer with deferred cleanup instead of
// time.After(), to avoid leaking goroutines on PeerManager.Close().
timer := time.NewTimer(retryDelay)
defer timer.Stop()
select {
case <-timer.C:
m.wakeDial()
case <-m.closeCh:
}
}()
m.wakeDial()
return nil
}
// Dialed marks a peer as successfully dialed. Any further incoming connections
// will be rejected, and once disconnected the peer may be dialed again.
func (m *PeerManager) Dialed(peerID NodeID, address NodeAddress) error {
m.mtx.Lock()
defer m.mtx.Unlock()
delete(m.dialing, peerID)
var upgradeFromPeer NodeID
for from, to := range m.upgrading {
if to == peerID {
delete(m.upgrading, from)
upgradeFromPeer = from
// Don't break, just in case this peer was marked as upgrading for
// multiple lower-scored peers (shouldn't really happen).
}
}
if m.connected[peerID] {
return fmt.Errorf("peer %v is already connected", peerID)
}
if m.options.MaxConnected > 0 &&
len(m.connected) >= int(m.options.MaxConnected)+int(m.options.MaxConnectedUpgrade) {
return fmt.Errorf("already connected to maximum number of peers")
}
peer, ok := m.store.Get(peerID)
if !ok {
return fmt.Errorf("peer %q was removed while dialing", peerID)
}
now := time.Now().UTC()
peer.LastConnected = now
if addressInfo, ok := peer.AddressInfo[address.String()]; ok {
addressInfo.DialFailures = 0
addressInfo.LastDialSuccess = now
// If not found, assume address has been removed.
}
if err := m.store.Set(peer); err != nil {
return err
}
if upgradeFromPeer != "" && m.options.MaxConnected > 0 &&
len(m.connected) >= int(m.options.MaxConnected) {
// Look for an even lower-scored peer that may have appeared
// since we started the upgrade.
if p, ok := m.store.Get(upgradeFromPeer); ok {
if u := m.findUpgradeCandidate(p.ID, p.Score()); u != "" {
upgradeFromPeer = u
}
}
m.evict[upgradeFromPeer] = true
}
m.connected[peerID] = true
m.wakeEvict()
return nil
}
// Accepted marks an incoming peer connection successfully accepted. If the peer
// is already connected or we don't allow additional connections then this will
// return an error.
//
// If full but MaxConnectedUpgrade is non-zero and the incoming peer is
// better-scored than any existing peers, then we accept it and evict a
// lower-scored peer.
//
// NOTE: We can't take an address here, since e.g. TCP uses a different port
// number for outbound traffic than inbound traffic, so the peer's endpoint
// wouldn't necessarily be an appropriate address to dial.
//
// FIXME: When we accept a connection from a peer, we should register that
// peer's address in the peer store so that we can dial it later. In order to do
// that, we'll need to get the remote address after all, but as noted above that
// can't be the remote endpoint since that will usually have the wrong port
// number.
func (m *PeerManager) Accepted(peerID NodeID) error {
m.mtx.Lock()
defer m.mtx.Unlock()
if m.connected[peerID] {
return fmt.Errorf("peer %q is already connected", peerID)
}
if m.options.MaxConnected > 0 &&
len(m.connected) >= int(m.options.MaxConnected)+int(m.options.MaxConnectedUpgrade) {
return fmt.Errorf("already connected to maximum number of peers")
}
peer, ok := m.store.Get(peerID)
if !ok {
peer = m.makePeerInfo(peerID)
}
// If all connections slots are full, but we allow upgrades (and we checked
// above that we have upgrade capacity), then we can look for a lower-scored
// peer to replace and if found accept the connection anyway and evict it.
var upgradeFromPeer NodeID
if m.options.MaxConnected > 0 && len(m.connected) >= int(m.options.MaxConnected) {
upgradeFromPeer = m.findUpgradeCandidate(peer.ID, peer.Score())
if upgradeFromPeer == "" {
return fmt.Errorf("already connected to maximum number of peers")
}
}
peer.LastConnected = time.Now().UTC()
if err := m.store.Set(peer); err != nil {
return err
}
m.connected[peerID] = true
if upgradeFromPeer != "" {
m.evict[upgradeFromPeer] = true
}
m.wakeEvict()
return nil
}
// Ready marks a peer as ready, broadcasting status updates to subscribers. The
// peer must already be marked as connected. This is separate from Dialed() and
// Accepted() to allow the router to set up its internal queues before reactors
// start sending messages.
func (m *PeerManager) Ready(peerID NodeID) {
m.mtx.Lock()
defer m.mtx.Unlock()
if m.connected[peerID] {
m.broadcast(PeerUpdate{
PeerID: peerID,
Status: PeerStatusUp,
})
}
}
// Disconnected unmarks a peer as connected, allowing new connections to be
// established.
func (m *PeerManager) Disconnected(peerID NodeID) error {
m.mtx.Lock()
defer m.mtx.Unlock()
delete(m.connected, peerID)
delete(m.upgrading, peerID)
delete(m.evict, peerID)
delete(m.evicting, peerID)
m.broadcast(PeerUpdate{
PeerID: peerID,
Status: PeerStatusDown,
})
m.wakeDial()
return nil
}
// EvictNext returns the next peer to evict (i.e. disconnect). If no evictable
// peers are found, the call will block until one becomes available or the
// context is cancelled.
func (m *PeerManager) EvictNext(ctx context.Context) (NodeID, error) {
for {
id, err := m.TryEvictNext()
if err != nil || id != "" {
return id, err
}
select {
case <-m.wakeEvictCh:
case <-ctx.Done():
return "", ctx.Err()
}
}
}
// TryEvictNext is equivalent to EvictNext, but immediately returns an empty
// node ID if no evictable peers are found.
func (m *PeerManager) TryEvictNext() (NodeID, error) {
m.mtx.Lock()
defer m.mtx.Unlock()
// If any connected peers are explicitly scheduled for eviction, we return a
// random one.
for peerID := range m.evict {
delete(m.evict, peerID)
if m.connected[peerID] && !m.evicting[peerID] {
m.evicting[peerID] = true
return peerID, nil
}
}
// If we're below capacity, we don't need to evict anything.
if m.options.MaxConnected == 0 ||
len(m.connected)-len(m.evicting) <= int(m.options.MaxConnected) {
return "", nil
}
// If we're above capacity, just pick the lowest-ranked peer to evict.
ranked := m.store.Ranked()
for i := len(ranked) - 1; i >= 0; i-- {
peer := ranked[i]
if m.connected[peer.ID] && !m.evicting[peer.ID] {
m.evicting[peer.ID] = true
return peer.ID, nil
}
}
return "", nil
}
// findUpgradeCandidate looks for a lower-scored peer that we could evict
// to make room for the given peer. Returns an empty ID if none is found.
// The caller must hold the mutex lock.
func (m *PeerManager) findUpgradeCandidate(id NodeID, score PeerScore) NodeID {
ranked := m.store.Ranked()
for i := len(ranked) - 1; i >= 0; i-- {
candidate := ranked[i]
switch {
case candidate.Score() >= score:
return "" // no further peers can be scored lower, due to sorting
case !m.connected[candidate.ID]:
case m.evict[candidate.ID]:
case m.evicting[candidate.ID]:
case m.upgrading[candidate.ID] != "":
default:
return candidate.ID
}
}
return ""
}
// GetHeight returns a peer's height, as reported via SetHeight. If the peer
// or height is unknown, this returns 0.
//
// FIXME: This is a temporary workaround for the peer state stored via the
// legacy Peer.Set() and Peer.Get() APIs, used to share height state between the
// consensus and mempool reactors. These dependencies should be removed from the
// reactors, and instead query this information independently via new P2P
// protocol additions.
func (m *PeerManager) GetHeight(peerID NodeID) int64 {
m.mtx.Lock()
defer m.mtx.Unlock()
peer, _ := m.store.Get(peerID)
return peer.Height
}
// SetHeight stores a peer's height, making it available via GetHeight. If the
// peer is unknown, it is created.
//
// FIXME: This is a temporary workaround for the peer state stored via the
// legacy Peer.Set() and Peer.Get() APIs, used to share height state between the
// consensus and mempool reactors. These dependencies should be removed from the
// reactors, and instead query this information independently via new P2P
// protocol additions.
func (m *PeerManager) SetHeight(peerID NodeID, height int64) error {
m.mtx.Lock()
defer m.mtx.Unlock()
peer, ok := m.store.Get(peerID)
if !ok {
peer = m.makePeerInfo(peerID)
}
peer.Height = height
return m.store.Set(peer)
}
// peerStore stores information about peers. It is not thread-safe, assuming
// it is used only by PeerManager which handles concurrency control, allowing
// it to execute multiple operations atomically via its own mutex.
//
// The entire set of peers is kept in memory, for performance. It is loaded
// from disk on initialization, and any changes are written back to disk
// (without fsync, since we can afford to lose recent writes).
type peerStore struct {
db dbm.DB
peers map[NodeID]*peerInfo
ranked []*peerInfo // cache for Ranked(), nil invalidates cache
}
// newPeerStore creates a new peer store, loading all persisted peers from the
// database into memory.
func newPeerStore(db dbm.DB) (*peerStore, error) {
store := &peerStore{
db: db,
}
if err := store.loadPeers(); err != nil {
return nil, err
}
return store, nil
}
// loadPeers loads all peers from the database into memory.
func (s *peerStore) loadPeers() error {
peers := make(map[NodeID]*peerInfo)
start, end := keyPeerInfoRange()
iter, err := s.db.Iterator(start, end)
if err != nil {
return err
}
defer iter.Close()
for ; iter.Valid(); iter.Next() {
// FIXME: We may want to tolerate failures here, by simply logging
// the errors and ignoring the faulty peer entries.
msg := new(p2pproto.PeerInfo)
if err := proto.Unmarshal(iter.Value(), msg); err != nil {
return fmt.Errorf("invalid peer Protobuf data: %w", err)
}
peer, err := peerInfoFromProto(msg)
if err != nil {
return fmt.Errorf("invalid peer data: %w", err)
}
peers[peer.ID] = peer
}
if iter.Error() != nil {
return iter.Error()
}
s.peers = peers
s.ranked = nil // invalidate cache if populated
return nil
}
// Get fetches a peer. The boolean indicates whether the peer existed or not.
// The returned peer info is a copy, and can be mutated at will.
func (s *peerStore) Get(id NodeID) (peerInfo, bool) {
peer, ok := s.peers[id]
return peer.Copy(), ok
}
// Set stores peer data. The input data will be copied, and can safely be reused
// by the caller.
func (s *peerStore) Set(peer peerInfo) error {
if err := peer.Validate(); err != nil {
return err
}
peer = peer.Copy()
// FIXME: We may want to optimize this by avoiding saving to the database
// if there haven't been any changes to persisted fields.
bz, err := peer.ToProto().Marshal()
if err != nil {
return err
}
if err = s.db.Set(keyPeerInfo(peer.ID), bz); err != nil {
return err
}
if current, ok := s.peers[peer.ID]; !ok || current.Score() != peer.Score() {
// If the peer is new, or its score changes, we invalidate the Ranked() cache.
s.peers[peer.ID] = &peer
s.ranked = nil
} else {
// Otherwise, since s.ranked contains pointers to the old data and we
// want those pointers to remain valid with the new data, we have to
// update the existing pointer address.
*current = peer
}
return nil
}
// Delete deletes a peer, or does nothing if it does not exist.
func (s *peerStore) Delete(id NodeID) error {
if _, ok := s.peers[id]; !ok {
return nil
}
if err := s.db.Delete(keyPeerInfo(id)); err != nil {
return err
}
delete(s.peers, id)
s.ranked = nil
return nil
}
// List retrieves all peers in an arbitrary order. The returned data is a copy,
// and can be mutated at will.
func (s *peerStore) List() []peerInfo {
peers := make([]peerInfo, 0, len(s.peers))
for _, peer := range s.peers {
peers = append(peers, peer.Copy())
}
return peers
}
// Ranked returns a list of peers ordered by score (better peers first). Peers
// with equal scores are returned in an arbitrary order. The returned list must
// not be mutated or accessed concurrently by the caller, since it returns
// pointers to internal peerStore data for performance.
//
// Ranked is used to determine both which peers to dial, which ones to evict,
// and which ones to delete completely.
//
// FIXME: For now, we simply maintain a cache in s.ranked which is invalidated
// by setting it to nil, but if necessary we should use a better data structure
// for this (e.g. a heap or ordered map).
//
// FIXME: The scoring logic is currently very naïve, see peerInfo.Score().
func (s *peerStore) Ranked() []*peerInfo {
if s.ranked != nil {
return s.ranked
}
s.ranked = make([]*peerInfo, 0, len(s.peers))
for _, peer := range s.peers {
s.ranked = append(s.ranked, peer)
}
sort.Slice(s.ranked, func(i, j int) bool {
// FIXME: If necessary, consider precomputing scores before sorting,
// to reduce the number of Score() calls.
return s.ranked[i].Score() > s.ranked[j].Score()
})
return s.ranked
}
// Size returns the number of peers in the peer store.
func (s *peerStore) Size() int {
return len(s.peers)
}
// peerInfo contains peer information stored in a peerStore.
type peerInfo struct {
ID NodeID
AddressInfo map[string]*peerAddressInfo
LastConnected time.Time
// These fields are ephemeral, i.e. not persisted to the database.
Persistent bool
Height int64
}
// peerInfoFromProto converts a Protobuf PeerInfo message to a peerInfo,
// erroring if the data is invalid.
func peerInfoFromProto(msg *p2pproto.PeerInfo) (*peerInfo, error) {
p := &peerInfo{
ID: NodeID(msg.ID),
AddressInfo: map[string]*peerAddressInfo{},
}
if msg.LastConnected != nil {
p.LastConnected = *msg.LastConnected
}
for _, addr := range msg.AddressInfo {
addressInfo, err := peerAddressInfoFromProto(addr)
if err != nil {
return nil, err
}
p.AddressInfo[addressInfo.Address.String()] = addressInfo
}
return p, p.Validate()
}
// ToProto converts the peerInfo to p2pproto.PeerInfo for database storage. The
// Protobuf type only contains persisted fields, while ephemeral fields are
// discarded. The returned message may contain pointers to original data, since
// it is expected to be serialized immediately.
func (p *peerInfo) ToProto() *p2pproto.PeerInfo {
msg := &p2pproto.PeerInfo{
ID: string(p.ID),
LastConnected: &p.LastConnected,
}
for _, addressInfo := range p.AddressInfo {
msg.AddressInfo = append(msg.AddressInfo, addressInfo.ToProto())
}
if msg.LastConnected.IsZero() {
msg.LastConnected = nil
}
return msg
}
// Copy returns a deep copy of the peer info.
func (p *peerInfo) Copy() peerInfo {
if p == nil {
return peerInfo{}
}
c := *p
for i, addressInfo := range c.AddressInfo {
addressInfoCopy := addressInfo.Copy()
c.AddressInfo[i] = &addressInfoCopy
}
return c
}
// Score calculates a score for the peer. Higher-scored peers will be
// preferred over lower scores.
func (p *peerInfo) Score() PeerScore {
var score PeerScore
if p.Persistent {
score += PeerScorePersistent
}
return score
}
// Validate validates the peer info.
func (p *peerInfo) Validate() error {
if p.ID == "" {
return errors.New("no peer ID")
}
return nil
}
// peerAddressInfo contains information and statistics about a peer address.
type peerAddressInfo struct {
Address NodeAddress
LastDialSuccess time.Time
LastDialFailure time.Time
DialFailures uint32 // since last successful dial
}
// peerAddressInfoFromProto converts a Protobuf PeerAddressInfo message
// to a peerAddressInfo.
func peerAddressInfoFromProto(msg *p2pproto.PeerAddressInfo) (*peerAddressInfo, error) {
address, err := ParseNodeAddress(msg.Address)
if err != nil {
return nil, fmt.Errorf("invalid address %q: %w", address, err)
}
addressInfo := &peerAddressInfo{
Address: address,
DialFailures: msg.DialFailures,
}
if msg.LastDialSuccess != nil {
addressInfo.LastDialSuccess = *msg.LastDialSuccess
}
if msg.LastDialFailure != nil {
addressInfo.LastDialFailure = *msg.LastDialFailure
}
return addressInfo, addressInfo.Validate()
}
// ToProto converts the address into to a Protobuf message for serialization.
func (a *peerAddressInfo) ToProto() *p2pproto.PeerAddressInfo {
msg := &p2pproto.PeerAddressInfo{
Address: a.Address.String(),
LastDialSuccess: &a.LastDialSuccess,
LastDialFailure: &a.LastDialFailure,
DialFailures: a.DialFailures,
}
if msg.LastDialSuccess.IsZero() {
msg.LastDialSuccess = nil
}
if msg.LastDialFailure.IsZero() {
msg.LastDialFailure = nil
}
return msg
}
// Copy returns a copy of the address info.
func (a *peerAddressInfo) Copy() peerAddressInfo {
return *a
}
// Validate validates the address info.
func (a *peerAddressInfo) Validate() error {
return a.Address.Validate()
}
// These are database key prefixes.
const (
prefixPeerInfo int64 = 1
)
// keyPeerInfo generates a peerInfo database key.
func keyPeerInfo(id NodeID) []byte {
key, err := orderedcode.Append(nil, prefixPeerInfo, string(id))
if err != nil {
panic(err)
}
return key
}
// keyPeerInfoPrefix generates start/end keys for the entire peerInfo key range.
func keyPeerInfoRange() ([]byte, []byte) {
start, err := orderedcode.Append(nil, prefixPeerInfo, "")
if err != nil {
panic(err)
}
end, err := orderedcode.Append(nil, prefixPeerInfo, orderedcode.Infinity)
if err != nil {
panic(err)
}
return start, end
}
// ============================================================================
// Types and business logic below may be deprecated.
//
// TODO: Rename once legacy p2p types are removed.
// ref: https://github.com/tendermint/tendermint/issues/5670
// ============================================================================
//go:generate mockery --case underscore --name Peer
const metricsTickerDuration = 10 * time.Second
// Peer is an interface representing a peer connected on a reactor.
type Peer interface {
service.Service
FlushStop()
ID() NodeID // peer's cryptographic ID
RemoteIP() net.IP // remote IP of the connection
RemoteAddr() net.Addr // remote address of the connection
IsOutbound() bool // did we dial the peer
IsPersistent() bool // do we redial this peer when we disconnect
CloseConn() error // close original connection
NodeInfo() NodeInfo // peer's info
Status() tmconn.ConnectionStatus
SocketAddr() *NetAddress // actual address of the socket
Send(byte, []byte) bool
TrySend(byte, []byte) bool
Set(string, interface{})
Get(string) interface{}
}
//----------------------------------------------------------
// peerConn contains the raw connection and its config.
type peerConn struct {
outbound bool
persistent bool
conn Connection
ip net.IP // cached RemoteIP()
}
func newPeerConn(outbound, persistent bool, conn Connection) peerConn {
return peerConn{
outbound: outbound,
persistent: persistent,
conn: conn,
}
}
// Return the IP from the connection RemoteAddr
func (pc peerConn) RemoteIP() net.IP {
if pc.ip == nil {
pc.ip = pc.conn.RemoteEndpoint().IP
}
return pc.ip
}
// peer implements Peer.
//
// Before using a peer, you will need to perform a handshake on connection.
type peer struct {
service.BaseService
// raw peerConn and the multiplex connection
peerConn
// peer's node info and the channel it knows about
// channels = nodeInfo.Channels
// cached to avoid copying nodeInfo in hasChannel
nodeInfo NodeInfo
channels []byte
reactors map[byte]Reactor
onPeerError func(Peer, interface{})
// User data
Data *cmap.CMap
metrics *Metrics
metricsTicker *time.Ticker
}
type PeerOption func(*peer)
func newPeer(
nodeInfo NodeInfo,
pc peerConn,
reactorsByCh map[byte]Reactor,
onPeerError func(Peer, interface{}),
options ...PeerOption,
) *peer {
p := &peer{
peerConn: pc,
nodeInfo: nodeInfo,
channels: nodeInfo.Channels, // TODO
reactors: reactorsByCh,
onPeerError: onPeerError,
Data: cmap.NewCMap(),
metricsTicker: time.NewTicker(metricsTickerDuration),
metrics: NopMetrics(),
}
p.BaseService = *service.NewBaseService(nil, "Peer", p)
for _, option := range options {
option(p)
}
return p
}
// onError calls the peer error callback.
func (p *peer) onError(err interface{}) {
p.onPeerError(p, err)
}
// String representation.
func (p *peer) String() string {
if p.outbound {
return fmt.Sprintf("Peer{%v %v out}", p.conn, p.ID())
}
return fmt.Sprintf("Peer{%v %v in}", p.conn, p.ID())
}
//---------------------------------------------------
// Implements service.Service
// SetLogger implements BaseService.
func (p *peer) SetLogger(l log.Logger) {
p.Logger = l
}
// OnStart implements BaseService.
func (p *peer) OnStart() error {
if err := p.BaseService.OnStart(); err != nil {
return err
}
go p.processMessages()
go p.metricsReporter()
return nil
}
// processMessages processes messages received from the connection.
func (p *peer) processMessages() {
defer func() {
if r := recover(); r != nil {
p.Logger.Error("peer message processing panic", "err", r, "stack", string(debug.Stack()))
p.onError(fmt.Errorf("panic during peer message processing: %v", r))
}
}()
for {
chID, msg, err := p.conn.ReceiveMessage()
if err != nil {
p.onError(err)
return
}
reactor, ok := p.reactors[byte(chID)]
if !ok {
p.onError(fmt.Errorf("unknown channel %v", chID))
return
}
reactor.Receive(byte(chID), p, msg)
}
}
// FlushStop mimics OnStop but additionally ensures that all successful
// .Send() calls will get flushed before closing the connection.
// NOTE: it is not safe to call this method more than once.
func (p *peer) FlushStop() {
p.metricsTicker.Stop()
p.BaseService.OnStop()
if err := p.conn.FlushClose(); err != nil {
p.Logger.Debug("error while stopping peer", "err", err)
}
}
// OnStop implements BaseService.
func (p *peer) OnStop() {
p.metricsTicker.Stop()
p.BaseService.OnStop()
if err := p.conn.Close(); err != nil {
p.Logger.Debug("error while stopping peer", "err", err)
}
}
//---------------------------------------------------
// Implements Peer
// ID returns the peer's ID - the hex encoded hash of its pubkey.
func (p *peer) ID() NodeID {
return p.nodeInfo.ID()
}
// IsOutbound returns true if the connection is outbound, false otherwise.
func (p *peer) IsOutbound() bool {
return p.peerConn.outbound
}
// IsPersistent returns true if the peer is persitent, false otherwise.
func (p *peer) IsPersistent() bool {
return p.peerConn.persistent
}
// NodeInfo returns a copy of the peer's NodeInfo.
func (p *peer) NodeInfo() NodeInfo {
return p.nodeInfo
}
// SocketAddr returns the address of the socket.
// For outbound peers, it's the address dialed (after DNS resolution).
// For inbound peers, it's the address returned by the underlying connection
// (not what's reported in the peer's NodeInfo).
func (p *peer) SocketAddr() *NetAddress {
endpoint := p.peerConn.conn.RemoteEndpoint()
return &NetAddress{
ID: p.ID(),
IP: endpoint.IP,
Port: endpoint.Port,
}
}
// Status returns the peer's ConnectionStatus.
func (p *peer) Status() tmconn.ConnectionStatus {
return p.conn.Status()
}
// Send msg bytes to the channel identified by chID byte. Returns false if the
// send queue is full after timeout, specified by MConnection.
func (p *peer) Send(chID byte, msgBytes []byte) bool {
if !p.IsRunning() {
// see Switch#Broadcast, where we fetch the list of peers and loop over
// them - while we're looping, one peer may be removed and stopped.
return false
} else if !p.hasChannel(chID) {
return false
}
res, err := p.conn.SendMessage(ChannelID(chID), msgBytes)
if err == io.EOF {
return false
} else if err != nil {
p.onError(err)
return false
}
if res {
labels := []string{
"peer_id", string(p.ID()),
"chID", fmt.Sprintf("%#x", chID),
}
p.metrics.PeerSendBytesTotal.With(labels...).Add(float64(len(msgBytes)))
}
return res
}
// TrySend msg bytes to the channel identified by chID byte. Immediately returns
// false if the send queue is full.
func (p *peer) TrySend(chID byte, msgBytes []byte) bool {
if !p.IsRunning() {
return false
} else if !p.hasChannel(chID) {
return false
}
res, err := p.conn.TrySendMessage(ChannelID(chID), msgBytes)
if err == io.EOF {
return false
} else if err != nil {
p.onError(err)
return false
}
if res {
labels := []string{
"peer_id", string(p.ID()),
"chID", fmt.Sprintf("%#x", chID),
}
p.metrics.PeerSendBytesTotal.With(labels...).Add(float64(len(msgBytes)))
}
return res
}
// Get the data for a given key.
func (p *peer) Get(key string) interface{} {
return p.Data.Get(key)
}
// Set sets the data for the given key.
func (p *peer) Set(key string, data interface{}) {
p.Data.Set(key, data)
}
// hasChannel returns true if the peer reported
// knowing about the given chID.
func (p *peer) hasChannel(chID byte) bool {
for _, ch := range p.channels {
if ch == chID {
return true
}
}
// NOTE: probably will want to remove this
// but could be helpful while the feature is new
p.Logger.Debug(
"Unknown channel for peer",
"channel",
chID,
"channels",
p.channels,
)
return false
}
// CloseConn closes original connection. Used for cleaning up in cases where the peer had not been started at all.
func (p *peer) CloseConn() error {
return p.peerConn.conn.Close()
}
//---------------------------------------------------
// methods only used for testing
// TODO: can we remove these?
// CloseConn closes the underlying connection
func (pc *peerConn) CloseConn() {
pc.conn.Close()
}
// RemoteAddr returns peer's remote network address.
func (p *peer) RemoteAddr() net.Addr {
endpoint := p.conn.RemoteEndpoint()
return &net.TCPAddr{
IP: endpoint.IP,
Port: int(endpoint.Port),
}
}
//---------------------------------------------------
func PeerMetrics(metrics *Metrics) PeerOption {
return func(p *peer) {
p.metrics = metrics
}
}
func (p *peer) metricsReporter() {
for {
select {
case <-p.metricsTicker.C:
status := p.conn.Status()
var sendQueueSize float64
for _, chStatus := range status.Channels {
sendQueueSize += float64(chStatus.SendQueueSize)
}
p.metrics.PeerPendingSendBytes.With("peer_id", string(p.ID())).Set(sendQueueSize)
case <-p.Quit():
return
}
}
}