neoneo-go/pkg/network/server.go
Roman Khimov eeeb0f6f0e core: accept two-side channels for sub/unsub, read on unsub
Blockchain's notificationDispatcher sends events to channels and these
channels must be read from. Unfortunately, regular service shutdown procedure
does unsubscription first (outside of the read loop) and only then drains the
channel. While it waits for unsubscription request to be accepted
notificationDispatcher can try pushing more data into the same channel which
will lead to a deadlock. Reading in the same method solves this, any number of
events can be pushed until unsub channel accepts the data.
2022-08-19 22:08:40 +03:00

1563 lines
45 KiB
Go

package network
import (
"crypto/rand"
"encoding/binary"
"errors"
"fmt"
"math/big"
mrand "math/rand"
"net"
"sort"
"strconv"
"sync"
"time"
"github.com/nspcc-dev/neo-go/pkg/config"
"github.com/nspcc-dev/neo-go/pkg/core/block"
"github.com/nspcc-dev/neo-go/pkg/core/mempool"
"github.com/nspcc-dev/neo-go/pkg/core/mempoolevent"
"github.com/nspcc-dev/neo-go/pkg/core/mpt"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/network/capability"
"github.com/nspcc-dev/neo-go/pkg/network/extpool"
"github.com/nspcc-dev/neo-go/pkg/network/payload"
"github.com/nspcc-dev/neo-go/pkg/util"
"go.uber.org/atomic"
"go.uber.org/zap"
)
const (
// peer numbers are arbitrary at the moment.
defaultMinPeers = 5
defaultAttemptConnPeers = 20
defaultMaxPeers = 100
defaultExtensiblePoolSize = 20
maxBlockBatch = 200
minPoolCount = 30
)
var (
errAlreadyConnected = errors.New("already connected")
errIdenticalID = errors.New("identical node id")
errInvalidNetwork = errors.New("invalid network")
errMaxPeers = errors.New("max peers reached")
errServerShutdown = errors.New("server shutdown")
errInvalidInvType = errors.New("invalid inventory type")
)
type (
// Ledger is everything Server needs from the blockchain.
Ledger interface {
extpool.Ledger
mempool.Feer
Blockqueuer
GetBlock(hash util.Uint256) (*block.Block, error)
GetConfig() config.ProtocolConfiguration
GetHeader(hash util.Uint256) (*block.Header, error)
GetHeaderHash(int) util.Uint256
GetMaxVerificationGAS() int64
GetMemPool() *mempool.Pool
GetNotaryBalance(acc util.Uint160) *big.Int
GetNotaryContractScriptHash() util.Uint160
GetNotaryDepositExpiration(acc util.Uint160) uint32
GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
HasBlock(util.Uint256) bool
HeaderHeight() uint32
P2PSigExtensionsEnabled() bool
PoolTx(t *transaction.Transaction, pools ...*mempool.Pool) error
PoolTxWithData(t *transaction.Transaction, data interface{}, mp *mempool.Pool, feer mempool.Feer, verificationFunction func(t *transaction.Transaction, data interface{}) error) error
RegisterPostBlock(f func(func(*transaction.Transaction, *mempool.Pool, bool) bool, *mempool.Pool, *block.Block))
SubscribeForBlocks(ch chan *block.Block)
UnsubscribeFromBlocks(ch chan *block.Block)
}
// Service is a service abstraction (oracle, state root, consensus, etc).
Service interface {
Name() string
Start()
Shutdown()
}
// Server represents the local Node in the network. Its transport could
// be of any kind.
Server struct {
// ServerConfig holds the Server configuration.
ServerConfig
// id also known as the nonce of the server.
id uint32
// A copy of the Ledger's config.
config config.ProtocolConfiguration
transport Transporter
discovery Discoverer
chain Ledger
bQueue *blockQueue
bSyncQueue *blockQueue
mempool *mempool.Pool
notaryRequestPool *mempool.Pool
extensiblePool *extpool.Pool
notaryFeer NotaryFeer
serviceLock sync.RWMutex
services map[string]Service
extensHandlers map[string]func(*payload.Extensible) error
txCallback func(*transaction.Transaction)
txInLock sync.Mutex
txInMap map[util.Uint256]struct{}
lock sync.RWMutex
peers map[Peer]bool
// lastRequestedBlock contains a height of the last requested block.
lastRequestedBlock atomic.Uint32
// lastRequestedHeader contains a height of the last requested header.
lastRequestedHeader atomic.Uint32
register chan Peer
unregister chan peerDrop
quit chan struct{}
relayFin chan struct{}
transactions chan *transaction.Transaction
syncReached *atomic.Bool
stateSync StateSync
log *zap.Logger
}
peerDrop struct {
peer Peer
reason error
}
)
func randomID() uint32 {
buf := make([]byte, 4)
_, _ = rand.Read(buf)
return binary.BigEndian.Uint32(buf)
}
// NewServer returns a new Server, initialized with the given configuration.
func NewServer(config ServerConfig, chain Ledger, stSync StateSync, log *zap.Logger) (*Server, error) {
return newServerFromConstructors(config, chain, stSync, log, func(s *Server) Transporter {
return NewTCPTransport(s, net.JoinHostPort(s.ServerConfig.Address, strconv.Itoa(int(s.ServerConfig.Port))), s.log)
}, newDefaultDiscovery)
}
func newServerFromConstructors(config ServerConfig, chain Ledger, stSync StateSync, log *zap.Logger,
newTransport func(*Server) Transporter,
newDiscovery func([]string, time.Duration, Transporter) Discoverer,
) (*Server, error) {
if log == nil {
return nil, errors.New("logger is a required parameter")
}
if config.ExtensiblePoolSize <= 0 {
config.ExtensiblePoolSize = defaultExtensiblePoolSize
log.Info("ExtensiblePoolSize is not set or wrong, using default value",
zap.Int("ExtensiblePoolSize", config.ExtensiblePoolSize))
}
s := &Server{
ServerConfig: config,
chain: chain,
id: randomID(),
config: chain.GetConfig(),
quit: make(chan struct{}),
relayFin: make(chan struct{}),
register: make(chan Peer),
unregister: make(chan peerDrop),
txInMap: make(map[util.Uint256]struct{}),
peers: make(map[Peer]bool),
syncReached: atomic.NewBool(false),
mempool: chain.GetMemPool(),
extensiblePool: extpool.New(chain, config.ExtensiblePoolSize),
log: log,
transactions: make(chan *transaction.Transaction, 64),
services: make(map[string]Service),
extensHandlers: make(map[string]func(*payload.Extensible) error),
stateSync: stSync,
}
if chain.P2PSigExtensionsEnabled() {
s.notaryFeer = NewNotaryFeer(chain)
s.notaryRequestPool = mempool.New(s.config.P2PNotaryRequestPayloadPoolSize, 1, true)
chain.RegisterPostBlock(func(isRelevant func(*transaction.Transaction, *mempool.Pool, bool) bool, txpool *mempool.Pool, _ *block.Block) {
s.notaryRequestPool.RemoveStale(func(t *transaction.Transaction) bool {
return isRelevant(t, txpool, true)
}, s.notaryFeer)
})
}
s.bQueue = newBlockQueue(maxBlockBatch, chain, log, func(b *block.Block) {
s.tryStartServices()
})
s.bSyncQueue = newBlockQueue(maxBlockBatch, s.stateSync, log, nil)
if s.MinPeers < 0 {
s.log.Info("bad MinPeers configured, using the default value",
zap.Int("configured", s.MinPeers),
zap.Int("actual", defaultMinPeers))
s.MinPeers = defaultMinPeers
}
if s.MaxPeers <= 0 {
s.log.Info("bad MaxPeers configured, using the default value",
zap.Int("configured", s.MaxPeers),
zap.Int("actual", defaultMaxPeers))
s.MaxPeers = defaultMaxPeers
}
if s.AttemptConnPeers <= 0 {
s.log.Info("bad AttemptConnPeers configured, using the default value",
zap.Int("configured", s.AttemptConnPeers),
zap.Int("actual", defaultAttemptConnPeers))
s.AttemptConnPeers = defaultAttemptConnPeers
}
s.transport = newTransport(s)
s.discovery = newDiscovery(
s.Seeds,
s.DialTimeout,
s.transport,
)
return s, nil
}
// ID returns the servers ID.
func (s *Server) ID() uint32 {
return s.id
}
// Start will start the server and its underlying transport. Calling it twice
// is an error.
func (s *Server) Start(errChan chan error) {
s.log.Info("node started",
zap.Uint32("blockHeight", s.chain.BlockHeight()),
zap.Uint32("headerHeight", s.chain.HeaderHeight()))
s.tryStartServices()
s.initStaleMemPools()
go s.broadcastTxLoop()
go s.relayBlocksLoop()
go s.bQueue.run()
go s.bSyncQueue.run()
go s.transport.Accept()
setServerAndNodeVersions(s.UserAgent, strconv.FormatUint(uint64(s.id), 10))
s.run()
}
// Shutdown disconnects all peers and stops listening. Calling it twice is an error,
// once stopped the same intance of the Server can't be started again by calling Start.
func (s *Server) Shutdown() {
s.log.Info("shutting down server", zap.Int("peers", s.PeerCount()))
s.transport.Close()
s.discovery.Close()
for _, p := range s.getPeers(nil) {
p.Disconnect(errServerShutdown)
}
s.bQueue.discard()
s.bSyncQueue.discard()
s.serviceLock.RLock()
for _, svc := range s.services {
svc.Shutdown()
}
s.serviceLock.RUnlock()
if s.chain.P2PSigExtensionsEnabled() {
s.notaryRequestPool.StopSubscriptions()
}
close(s.quit)
<-s.relayFin
}
// AddService allows to add a service to be started/stopped by Server.
func (s *Server) AddService(svc Service) {
s.serviceLock.Lock()
defer s.serviceLock.Unlock()
s.addService(svc)
}
// addService is an unlocked version of AddService.
func (s *Server) addService(svc Service) {
s.services[svc.Name()] = svc
}
// AddExtensibleService register a service that handles an extensible payload of some kind.
func (s *Server) AddExtensibleService(svc Service, category string, handler func(*payload.Extensible) error) {
s.serviceLock.Lock()
defer s.serviceLock.Unlock()
s.addExtensibleService(svc, category, handler)
}
// addExtensibleService is an unlocked version of AddExtensibleService.
func (s *Server) addExtensibleService(svc Service, category string, handler func(*payload.Extensible) error) {
s.extensHandlers[category] = handler
s.addService(svc)
}
// AddConsensusService registers consensus service that handles transactions and dBFT extensible payloads.
func (s *Server) AddConsensusService(svc Service, handler func(*payload.Extensible) error, txCallback func(*transaction.Transaction)) {
s.serviceLock.Lock()
defer s.serviceLock.Unlock()
s.txCallback = txCallback
s.addExtensibleService(svc, payload.ConsensusCategory, handler)
}
// DelService drops a service from the list, use it when the service is stopped
// outside of the Server.
func (s *Server) DelService(svc Service) {
s.serviceLock.Lock()
defer s.serviceLock.Unlock()
s.delService(svc)
}
// delService is an unlocked version of DelService.
func (s *Server) delService(svc Service) {
delete(s.services, svc.Name())
}
// DelExtensibleService drops a service that handler extensible payloads from the
// list, use it when the service is stopped outside of the Server.
func (s *Server) DelExtensibleService(svc Service, category string) {
s.serviceLock.Lock()
defer s.serviceLock.Unlock()
s.delExtensibleService(svc, category)
}
// delExtensibleService is an unlocked version of DelExtensibleService.
func (s *Server) delExtensibleService(svc Service, category string) {
delete(s.extensHandlers, category)
s.delService(svc)
}
// DelConsensusService unregisters consensus service that handles transactions and dBFT extensible payloads.
func (s *Server) DelConsensusService(svc Service) {
s.serviceLock.Lock()
defer s.serviceLock.Unlock()
s.txCallback = nil
s.delExtensibleService(svc, payload.ConsensusCategory)
}
// GetNotaryPool allows to retrieve notary pool, if it's configured.
func (s *Server) GetNotaryPool() *mempool.Pool {
return s.notaryRequestPool
}
// UnconnectedPeers returns a list of peers that are in the discovery peer list
// but are not connected to the server.
func (s *Server) UnconnectedPeers() []string {
return s.discovery.UnconnectedPeers()
}
// BadPeers returns a list of peers that are flagged as "bad" peers.
func (s *Server) BadPeers() []string {
return s.discovery.BadPeers()
}
// ConnectedPeers returns a list of currently connected peers.
func (s *Server) ConnectedPeers() []string {
s.lock.RLock()
defer s.lock.RUnlock()
peers := make([]string, 0, len(s.peers))
for k := range s.peers {
peers = append(peers, k.PeerAddr().String())
}
return peers
}
// run is a goroutine that starts another goroutine to manage protocol specifics
// while itself dealing with peers management (handling connects/disconnects).
func (s *Server) run() {
go s.runProto()
for {
if s.PeerCount() < s.MinPeers {
s.discovery.RequestRemote(s.AttemptConnPeers)
}
if s.discovery.PoolCount() < minPoolCount {
s.broadcastHPMessage(NewMessage(CMDGetAddr, payload.NewNullPayload()))
}
select {
case <-s.quit:
return
case p := <-s.register:
s.lock.Lock()
s.peers[p] = true
s.lock.Unlock()
peerCount := s.PeerCount()
s.log.Info("new peer connected", zap.Stringer("addr", p.RemoteAddr()), zap.Int("peerCount", peerCount))
if peerCount > s.MaxPeers {
s.lock.RLock()
// Pick a random peer and drop connection to it.
for peer := range s.peers {
// It will send us unregister signal.
go peer.Disconnect(errMaxPeers)
break
}
s.lock.RUnlock()
}
updatePeersConnectedMetric(s.PeerCount())
case drop := <-s.unregister:
s.lock.Lock()
if s.peers[drop.peer] {
delete(s.peers, drop.peer)
s.lock.Unlock()
s.log.Warn("peer disconnected",
zap.Stringer("addr", drop.peer.RemoteAddr()),
zap.Error(drop.reason),
zap.Int("peerCount", s.PeerCount()))
addr := drop.peer.PeerAddr().String()
if drop.reason == errIdenticalID {
s.discovery.RegisterBadAddr(addr)
} else if drop.reason == errAlreadyConnected {
// There is a race condition when peer can be disconnected twice for the this reason
// which can lead to no connections to peer at all. Here we check for such a possibility.
stillConnected := false
s.lock.RLock()
verDrop := drop.peer.Version()
addr := drop.peer.PeerAddr().String()
if verDrop != nil {
for peer := range s.peers {
ver := peer.Version()
// Already connected, drop this connection.
if ver != nil && ver.Nonce == verDrop.Nonce && peer.PeerAddr().String() == addr {
stillConnected = true
}
}
}
s.lock.RUnlock()
if !stillConnected {
s.discovery.UnregisterConnectedAddr(addr)
s.discovery.BackFill(addr)
}
} else {
s.discovery.UnregisterConnectedAddr(addr)
s.discovery.BackFill(addr)
}
updatePeersConnectedMetric(s.PeerCount())
} else {
// else the peer is already gone, which can happen
// because we have two goroutines sending signals here
s.lock.Unlock()
}
}
}
}
// runProto is a goroutine that manages server-wide protocol events.
func (s *Server) runProto() {
pingTimer := time.NewTimer(s.PingInterval)
for {
prevHeight := s.chain.BlockHeight()
select {
case <-s.quit:
return
case <-pingTimer.C:
if s.chain.BlockHeight() == prevHeight {
// Get a copy of s.peers to avoid holding a lock while sending.
for _, peer := range s.getPeers(nil) {
_ = peer.SendPing(NewMessage(CMDPing, payload.NewPing(s.chain.BlockHeight(), s.id)))
}
}
pingTimer.Reset(s.PingInterval)
}
}
}
func (s *Server) tryStartServices() {
if s.syncReached.Load() {
return
}
if s.IsInSync() && s.syncReached.CAS(false, true) {
s.log.Info("node reached synchronized state, starting services")
if s.chain.P2PSigExtensionsEnabled() {
s.notaryRequestPool.RunSubscriptions() // WSClient is also a subscriber.
}
s.serviceLock.RLock()
for _, svc := range s.services {
svc.Start()
}
s.serviceLock.RUnlock()
}
}
// SubscribeForNotaryRequests adds the given channel to a notary request event
// broadcasting, so when a new P2PNotaryRequest is received or an existing
// P2PNotaryRequest is removed from the pool you'll receive it via this channel.
// Make sure it's read from regularly as not reading these events might affect
// other Server functions.
// Ensure that P2PSigExtensions are enabled before calling this method.
func (s *Server) SubscribeForNotaryRequests(ch chan<- mempoolevent.Event) {
if !s.chain.P2PSigExtensionsEnabled() {
panic("P2PSigExtensions are disabled")
}
s.notaryRequestPool.SubscribeForTransactions(ch)
}
// UnsubscribeFromNotaryRequests unsubscribes the given channel from notary request
// notifications, you can close it afterwards. Passing non-subscribed channel
// is a no-op.
// Ensure that P2PSigExtensions are enabled before calling this method.
func (s *Server) UnsubscribeFromNotaryRequests(ch chan<- mempoolevent.Event) {
if !s.chain.P2PSigExtensionsEnabled() {
panic("P2PSigExtensions are disabled")
}
s.notaryRequestPool.UnsubscribeFromTransactions(ch)
}
// getPeers returns the current list of the peers connected to the server filtered by
// isOK function if it's given.
func (s *Server) getPeers(isOK func(Peer) bool) []Peer {
s.lock.RLock()
defer s.lock.RUnlock()
peers := make([]Peer, 0, len(s.peers))
for k := range s.peers {
if isOK != nil && !isOK(k) {
continue
}
peers = append(peers, k)
}
return peers
}
// PeerCount returns the number of the currently connected peers.
func (s *Server) PeerCount() int {
s.lock.RLock()
defer s.lock.RUnlock()
return len(s.peers)
}
// HandshakedPeersCount returns the number of the connected peers
// which have already performed handshake.
func (s *Server) HandshakedPeersCount() int {
s.lock.RLock()
defer s.lock.RUnlock()
var count int
for p := range s.peers {
if p.Handshaked() {
count++
}
}
return count
}
// getVersionMsg returns the current version message.
func (s *Server) getVersionMsg() (*Message, error) {
port, err := s.Port()
if err != nil {
return nil, err
}
capabilities := []capability.Capability{
{
Type: capability.TCPServer,
Data: &capability.Server{
Port: port,
},
},
}
if s.Relay {
capabilities = append(capabilities, capability.Capability{
Type: capability.FullNode,
Data: &capability.Node{
StartHeight: s.chain.BlockHeight(),
},
})
}
payload := payload.NewVersion(
s.Net,
s.id,
s.UserAgent,
capabilities,
)
return NewMessage(CMDVersion, payload), nil
}
// IsInSync answers the question of whether the server is in sync with the
// network or not (at least how the server itself sees it). The server operates
// with the data that it has, the number of peers (that has to be more than
// minimum number) and the height of these peers (our chain has to be not lower
// than 2/3 of our peers have). Ideally, we would check for the highest of the
// peers, but the problem is that they can lie to us and send whatever height
// they want to. Once sync reached, IsInSync will always return `true`, even if
// server is temporary out of sync after that.
func (s *Server) IsInSync() bool {
if s.syncReached.Load() {
return true
}
var peersNumber int
var notHigher int
if s.stateSync.IsActive() {
return false
}
if s.MinPeers == 0 {
return true
}
ourLastBlock := s.chain.BlockHeight()
s.lock.RLock()
for p := range s.peers {
if p.Handshaked() {
peersNumber++
if ourLastBlock >= p.LastBlockIndex() {
notHigher++
}
}
}
s.lock.RUnlock()
// Checking bQueue would also be nice, but it can be filled with garbage
// easily at the moment.
return peersNumber >= s.MinPeers && (3*notHigher > 2*peersNumber) // && s.bQueue.length() == 0
}
// When a peer sends out its version, we reply with verack after validating
// the version.
func (s *Server) handleVersionCmd(p Peer, version *payload.Version) error {
err := p.HandleVersion(version)
if err != nil {
return err
}
if s.id == version.Nonce {
return errIdenticalID
}
// Make sure both the server and the peer are operating on
// the same network.
if s.Net != version.Magic {
return errInvalidNetwork
}
peerAddr := p.PeerAddr().String()
s.discovery.RegisterConnectedAddr(peerAddr)
s.lock.RLock()
for peer := range s.peers {
if p == peer {
continue
}
ver := peer.Version()
// Already connected, drop this connection.
if ver != nil && ver.Nonce == version.Nonce && peer.PeerAddr().String() == peerAddr {
s.lock.RUnlock()
return errAlreadyConnected
}
}
s.lock.RUnlock()
return p.SendVersionAck(NewMessage(CMDVerack, payload.NewNullPayload()))
}
// handleBlockCmd processes the block received from its peer.
func (s *Server) handleBlockCmd(p Peer, block *block.Block) error {
if s.stateSync.IsActive() {
return s.bSyncQueue.putBlock(block)
}
return s.bQueue.putBlock(block)
}
// handlePing processes a ping request.
func (s *Server) handlePing(p Peer, ping *payload.Ping) error {
err := p.HandlePing(ping)
if err != nil {
return err
}
err = s.requestBlocksOrHeaders(p)
if err != nil {
return err
}
return p.EnqueueP2PMessage(NewMessage(CMDPong, payload.NewPing(s.chain.BlockHeight(), s.id)))
}
func (s *Server) requestBlocksOrHeaders(p Peer) error {
if s.stateSync.NeedHeaders() {
if s.chain.HeaderHeight() < p.LastBlockIndex() {
return s.requestHeaders(p)
}
return nil
}
var (
bq Blockqueuer = s.chain
requestMPTNodes bool
)
if s.stateSync.IsActive() {
bq = s.stateSync
requestMPTNodes = s.stateSync.NeedMPTNodes()
}
if bq.BlockHeight() >= p.LastBlockIndex() {
return nil
}
err := s.requestBlocks(bq, p)
if err != nil {
return err
}
if requestMPTNodes {
return s.requestMPTNodes(p, s.stateSync.GetUnknownMPTNodesBatch(payload.MaxMPTHashesCount))
}
return nil
}
// requestHeaders sends a CMDGetHeaders message to the peer to sync up in headers.
func (s *Server) requestHeaders(p Peer) error {
pl := getRequestBlocksPayload(p, s.chain.HeaderHeight(), &s.lastRequestedHeader)
return p.EnqueueP2PMessage(NewMessage(CMDGetHeaders, pl))
}
// handlePing processes a pong request.
func (s *Server) handlePong(p Peer, pong *payload.Ping) error {
err := p.HandlePong(pong)
if err != nil {
return err
}
return s.requestBlocksOrHeaders(p)
}
// handleInvCmd processes the received inventory.
func (s *Server) handleInvCmd(p Peer, inv *payload.Inventory) error {
reqHashes := make([]util.Uint256, 0)
var typExists = map[payload.InventoryType]func(util.Uint256) bool{
payload.TXType: s.mempool.ContainsKey,
payload.BlockType: s.chain.HasBlock,
payload.ExtensibleType: func(h util.Uint256) bool {
cp := s.extensiblePool.Get(h)
return cp != nil
},
payload.P2PNotaryRequestType: func(h util.Uint256) bool {
return s.notaryRequestPool.ContainsKey(h)
},
}
if exists := typExists[inv.Type]; exists != nil {
for _, hash := range inv.Hashes {
if !exists(hash) {
reqHashes = append(reqHashes, hash)
}
}
}
if len(reqHashes) > 0 {
msg := NewMessage(CMDGetData, payload.NewInventory(inv.Type, reqHashes))
pkt, err := msg.Bytes()
if err != nil {
return err
}
if inv.Type == payload.ExtensibleType {
return p.EnqueueHPPacket(true, pkt)
}
return p.EnqueueP2PPacket(pkt)
}
return nil
}
// handleMempoolCmd handles getmempool command.
func (s *Server) handleMempoolCmd(p Peer) error {
txs := s.mempool.GetVerifiedTransactions()
hs := make([]util.Uint256, 0, payload.MaxHashesCount)
for i := range txs {
hs = append(hs, txs[i].Hash())
if len(hs) < payload.MaxHashesCount && i != len(txs)-1 {
continue
}
msg := NewMessage(CMDInv, payload.NewInventory(payload.TXType, hs))
err := p.EnqueueP2PMessage(msg)
if err != nil {
return err
}
hs = hs[:0]
}
return nil
}
// handleInvCmd processes the received inventory.
func (s *Server) handleGetDataCmd(p Peer, inv *payload.Inventory) error {
var notFound []util.Uint256
for _, hash := range inv.Hashes {
var msg *Message
switch inv.Type {
case payload.TXType:
tx, _, err := s.chain.GetTransaction(hash)
if err == nil {
msg = NewMessage(CMDTX, tx)
} else {
notFound = append(notFound, hash)
}
case payload.BlockType:
b, err := s.chain.GetBlock(hash)
if err == nil {
msg = NewMessage(CMDBlock, b)
} else {
notFound = append(notFound, hash)
}
case payload.ExtensibleType:
if cp := s.extensiblePool.Get(hash); cp != nil {
msg = NewMessage(CMDExtensible, cp)
}
case payload.P2PNotaryRequestType:
if nrp, ok := s.notaryRequestPool.TryGetData(hash); ok { // already have checked P2PSigExtEnabled
msg = NewMessage(CMDP2PNotaryRequest, nrp.(*payload.P2PNotaryRequest))
} else {
notFound = append(notFound, hash)
}
}
if msg != nil {
pkt, err := msg.Bytes()
if err == nil {
if inv.Type == payload.ExtensibleType {
err = p.EnqueueHPPacket(true, pkt)
} else {
err = p.EnqueueP2PPacket(pkt)
}
}
if err != nil {
return err
}
}
}
if len(notFound) != 0 {
return p.EnqueueP2PMessage(NewMessage(CMDNotFound, payload.NewInventory(inv.Type, notFound)))
}
return nil
}
// handleGetMPTDataCmd processes the received MPT inventory.
func (s *Server) handleGetMPTDataCmd(p Peer, inv *payload.MPTInventory) error {
if !s.config.P2PStateExchangeExtensions {
return errors.New("GetMPTDataCMD was received, but P2PStateExchangeExtensions are disabled")
}
// Even if s.config.KeepOnlyLatestState enabled, we'll keep latest P1 and P2 MPT states.
resp := payload.MPTData{}
capLeft := payload.MaxSize - 8 // max(io.GetVarSize(len(resp.Nodes)))
added := make(map[util.Uint256]struct{})
for _, h := range inv.Hashes {
if capLeft <= 2 { // at least 1 byte for len(nodeBytes) and 1 byte for node type
break
}
err := s.stateSync.Traverse(h,
func(n mpt.Node, node []byte) bool {
if _, ok := added[n.Hash()]; ok {
return false
}
l := len(node)
size := l + io.GetVarSize(l)
if size > capLeft {
return true
}
resp.Nodes = append(resp.Nodes, node)
added[n.Hash()] = struct{}{}
capLeft -= size
return false
})
if err != nil {
return fmt.Errorf("failed to traverse MPT starting from %s: %w", h.StringBE(), err)
}
}
if len(resp.Nodes) > 0 {
msg := NewMessage(CMDMPTData, &resp)
return p.EnqueueP2PMessage(msg)
}
return nil
}
func (s *Server) handleMPTDataCmd(p Peer, data *payload.MPTData) error {
if !s.config.P2PStateExchangeExtensions {
return errors.New("MPTDataCMD was received, but P2PStateExchangeExtensions are disabled")
}
return s.stateSync.AddMPTNodes(data.Nodes)
}
// requestMPTNodes requests the specified MPT nodes from the peer or broadcasts
// request if no peer is specified.
func (s *Server) requestMPTNodes(p Peer, itms []util.Uint256) error {
if len(itms) == 0 {
return nil
}
if len(itms) > payload.MaxMPTHashesCount {
itms = itms[:payload.MaxMPTHashesCount]
}
pl := payload.NewMPTInventory(itms)
msg := NewMessage(CMDGetMPTData, pl)
return p.EnqueueP2PMessage(msg)
}
// handleGetBlocksCmd processes the getblocks request.
func (s *Server) handleGetBlocksCmd(p Peer, gb *payload.GetBlocks) error {
count := gb.Count
if gb.Count < 0 || gb.Count > payload.MaxHashesCount {
count = payload.MaxHashesCount
}
start, err := s.chain.GetHeader(gb.HashStart)
if err != nil {
return err
}
blockHashes := make([]util.Uint256, 0)
for i := start.Index + 1; i <= start.Index+uint32(count); i++ {
hash := s.chain.GetHeaderHash(int(i))
if hash.Equals(util.Uint256{}) {
break
}
blockHashes = append(blockHashes, hash)
}
if len(blockHashes) == 0 {
return nil
}
payload := payload.NewInventory(payload.BlockType, blockHashes)
msg := NewMessage(CMDInv, payload)
return p.EnqueueP2PMessage(msg)
}
// handleGetBlockByIndexCmd processes the getblockbyindex request.
func (s *Server) handleGetBlockByIndexCmd(p Peer, gbd *payload.GetBlockByIndex) error {
count := gbd.Count
if gbd.Count < 0 || gbd.Count > payload.MaxHashesCount {
count = payload.MaxHashesCount
}
for i := gbd.IndexStart; i < gbd.IndexStart+uint32(count); i++ {
hash := s.chain.GetHeaderHash(int(i))
if hash.Equals(util.Uint256{}) {
break
}
b, err := s.chain.GetBlock(hash)
if err != nil {
break
}
msg := NewMessage(CMDBlock, b)
if err = p.EnqueueP2PMessage(msg); err != nil {
return err
}
}
return nil
}
// handleGetHeadersCmd processes the getheaders request.
func (s *Server) handleGetHeadersCmd(p Peer, gh *payload.GetBlockByIndex) error {
if gh.IndexStart > s.chain.HeaderHeight() {
return nil
}
count := gh.Count
if gh.Count < 0 || gh.Count > payload.MaxHeadersAllowed {
count = payload.MaxHeadersAllowed
}
resp := payload.Headers{}
resp.Hdrs = make([]*block.Header, 0, count)
for i := gh.IndexStart; i < gh.IndexStart+uint32(count); i++ {
hash := s.chain.GetHeaderHash(int(i))
if hash.Equals(util.Uint256{}) {
break
}
header, err := s.chain.GetHeader(hash)
if err != nil {
break
}
resp.Hdrs = append(resp.Hdrs, header)
}
if len(resp.Hdrs) == 0 {
return nil
}
msg := NewMessage(CMDHeaders, &resp)
return p.EnqueueP2PMessage(msg)
}
// handleHeadersCmd processes headers payload.
func (s *Server) handleHeadersCmd(p Peer, h *payload.Headers) error {
return s.stateSync.AddHeaders(h.Hdrs...)
}
// handleExtensibleCmd processes the received extensible payload.
func (s *Server) handleExtensibleCmd(e *payload.Extensible) error {
if !s.syncReached.Load() {
return nil
}
ok, err := s.extensiblePool.Add(e)
if err != nil {
return err
}
if !ok { // payload is already in cache
return nil
}
s.serviceLock.RLock()
handler := s.extensHandlers[e.Category]
s.serviceLock.RUnlock()
if handler != nil {
err = handler(e)
if err != nil {
return err
}
}
s.advertiseExtensible(e)
return nil
}
func (s *Server) advertiseExtensible(e *payload.Extensible) {
msg := NewMessage(CMDInv, payload.NewInventory(payload.ExtensibleType, []util.Uint256{e.Hash()}))
if e.Category == payload.ConsensusCategory {
// It's high priority because it directly affects consensus process,
// even though it's just an inv.
s.broadcastHPMessage(msg)
} else {
s.broadcastMessage(msg)
}
}
// handleTxCmd processes the received transaction.
// It never returns an error.
func (s *Server) handleTxCmd(tx *transaction.Transaction) error {
// It's OK for it to fail for various reasons like tx already existing
// in the pool.
s.txInLock.Lock()
_, ok := s.txInMap[tx.Hash()]
if ok || s.mempool.ContainsKey(tx.Hash()) {
s.txInLock.Unlock()
return nil
}
s.txInMap[tx.Hash()] = struct{}{}
s.txInLock.Unlock()
s.serviceLock.RLock()
txCallback := s.txCallback
s.serviceLock.RUnlock()
if txCallback != nil {
txCallback(tx)
}
if s.verifyAndPoolTX(tx) == nil {
s.broadcastTX(tx, nil)
}
s.txInLock.Lock()
delete(s.txInMap, tx.Hash())
s.txInLock.Unlock()
return nil
}
// handleP2PNotaryRequestCmd process the received P2PNotaryRequest payload.
func (s *Server) handleP2PNotaryRequestCmd(r *payload.P2PNotaryRequest) error {
if !s.chain.P2PSigExtensionsEnabled() {
return errors.New("P2PNotaryRequestCMD was received, but P2PSignatureExtensions are disabled")
}
// It's OK for it to fail for various reasons like request already existing
// in the pool.
_ = s.RelayP2PNotaryRequest(r)
return nil
}
// RelayP2PNotaryRequest adds the given request to the pool and relays. It does not check
// P2PSigExtensions enabled.
func (s *Server) RelayP2PNotaryRequest(r *payload.P2PNotaryRequest) error {
err := s.verifyAndPoolNotaryRequest(r)
if err == nil {
s.broadcastP2PNotaryRequestPayload(nil, r)
}
return err
}
// verifyAndPoolNotaryRequest verifies NotaryRequest payload and adds it to the payload mempool.
func (s *Server) verifyAndPoolNotaryRequest(r *payload.P2PNotaryRequest) error {
return s.chain.PoolTxWithData(r.FallbackTransaction, r, s.notaryRequestPool, s.notaryFeer, s.verifyNotaryRequest)
}
// verifyNotaryRequest is a function for state-dependant P2PNotaryRequest payload verification which is executed before ordinary blockchain's verification.
func (s *Server) verifyNotaryRequest(_ *transaction.Transaction, data interface{}) error {
r := data.(*payload.P2PNotaryRequest)
payer := r.FallbackTransaction.Signers[1].Account
if _, err := s.chain.VerifyWitness(payer, r, &r.Witness, s.chain.GetMaxVerificationGAS()); err != nil {
return fmt.Errorf("bad P2PNotaryRequest payload witness: %w", err)
}
notaryHash := s.chain.GetNotaryContractScriptHash()
if r.FallbackTransaction.Sender() != notaryHash {
return errors.New("P2PNotary contract should be a sender of the fallback transaction")
}
depositExpiration := s.chain.GetNotaryDepositExpiration(payer)
if r.FallbackTransaction.ValidUntilBlock >= depositExpiration {
return fmt.Errorf("fallback transaction is valid after deposit is unlocked: ValidUntilBlock is %d, deposit lock expires at %d", r.FallbackTransaction.ValidUntilBlock, depositExpiration)
}
return nil
}
func (s *Server) broadcastP2PNotaryRequestPayload(_ *transaction.Transaction, data interface{}) {
r := data.(*payload.P2PNotaryRequest) // we can guarantee that cast is successful
msg := NewMessage(CMDInv, payload.NewInventory(payload.P2PNotaryRequestType, []util.Uint256{r.FallbackTransaction.Hash()}))
s.broadcastMessage(msg)
}
// handleAddrCmd will process the received addresses.
func (s *Server) handleAddrCmd(p Peer, addrs *payload.AddressList) error {
if !p.CanProcessAddr() {
return errors.New("unexpected addr received")
}
dups := make(map[string]bool)
for _, a := range addrs.Addrs {
addr, err := a.GetTCPAddress()
if err == nil && !dups[addr] {
dups[addr] = true
s.discovery.BackFill(addr)
}
}
return nil
}
// handleGetAddrCmd sends to the peer some good addresses that we know of.
func (s *Server) handleGetAddrCmd(p Peer) error {
addrs := s.discovery.GoodPeers()
if len(addrs) > payload.MaxAddrsCount {
addrs = addrs[:payload.MaxAddrsCount]
}
alist := payload.NewAddressList(len(addrs))
ts := time.Now()
for i, addr := range addrs {
// we know it's a good address, so it can't fail
netaddr, _ := net.ResolveTCPAddr("tcp", addr.Address)
alist.Addrs[i] = payload.NewAddressAndTime(netaddr, ts, addr.Capabilities)
}
return p.EnqueueP2PMessage(NewMessage(CMDAddr, alist))
}
// requestBlocks sends a CMDGetBlockByIndex message to the peer
// to sync up in blocks. A maximum of maxBlockBatch will be
// sent at once. There are two things we need to take care of:
// 1. If possible, blocks should be fetched in parallel.
// height..+500 to one peer, height+500..+1000 to another etc.
// 2. Every block must eventually be fetched even if the peer sends no answer.
//
// Thus, the following algorithm is used:
// 1. Block range is divided into chunks of payload.MaxHashesCount.
// 2. Send requests for chunk in increasing order.
// 3. After all requests have been sent, request random height.
func (s *Server) requestBlocks(bq Blockqueuer, p Peer) error {
h := bq.BlockHeight()
pl := getRequestBlocksPayload(p, h, &s.lastRequestedBlock)
lq := s.bQueue.lastQueued()
if lq > pl.IndexStart {
c := int16(h + blockCacheSize - lq)
if c < payload.MaxHashesCount {
pl.Count = c
}
pl.IndexStart = lq + 1
}
return p.EnqueueP2PMessage(NewMessage(CMDGetBlockByIndex, pl))
}
func getRequestBlocksPayload(p Peer, currHeight uint32, lastRequestedHeight *atomic.Uint32) *payload.GetBlockByIndex {
var peerHeight = p.LastBlockIndex()
var needHeight uint32
// lastRequestedBlock can only be increased.
for {
old := lastRequestedHeight.Load()
if old <= currHeight {
needHeight = currHeight + 1
if !lastRequestedHeight.CAS(old, needHeight) {
continue
}
} else if old < currHeight+(blockCacheSize-payload.MaxHashesCount) {
needHeight = currHeight + 1
if peerHeight > old+payload.MaxHashesCount {
needHeight = old + payload.MaxHashesCount
if !lastRequestedHeight.CAS(old, needHeight) {
continue
}
}
} else {
index := mrand.Intn(blockCacheSize / payload.MaxHashesCount)
needHeight = currHeight + 1 + uint32(index*payload.MaxHashesCount)
}
break
}
return payload.NewGetBlockByIndex(needHeight, -1)
}
// handleMessage processes the given message.
func (s *Server) handleMessage(peer Peer, msg *Message) error {
s.log.Debug("got msg",
zap.Stringer("addr", peer.RemoteAddr()),
zap.String("type", msg.Command.String()))
if peer.Handshaked() {
if inv, ok := msg.Payload.(*payload.Inventory); ok {
if !inv.Type.Valid(s.chain.P2PSigExtensionsEnabled()) || len(inv.Hashes) == 0 {
return errInvalidInvType
}
}
switch msg.Command {
case CMDAddr:
addrs := msg.Payload.(*payload.AddressList)
return s.handleAddrCmd(peer, addrs)
case CMDGetAddr:
// it has no payload
return s.handleGetAddrCmd(peer)
case CMDGetBlocks:
gb := msg.Payload.(*payload.GetBlocks)
return s.handleGetBlocksCmd(peer, gb)
case CMDGetBlockByIndex:
gbd := msg.Payload.(*payload.GetBlockByIndex)
return s.handleGetBlockByIndexCmd(peer, gbd)
case CMDGetData:
inv := msg.Payload.(*payload.Inventory)
return s.handleGetDataCmd(peer, inv)
case CMDGetMPTData:
inv := msg.Payload.(*payload.MPTInventory)
return s.handleGetMPTDataCmd(peer, inv)
case CMDMPTData:
inv := msg.Payload.(*payload.MPTData)
return s.handleMPTDataCmd(peer, inv)
case CMDGetHeaders:
gh := msg.Payload.(*payload.GetBlockByIndex)
return s.handleGetHeadersCmd(peer, gh)
case CMDHeaders:
h := msg.Payload.(*payload.Headers)
return s.handleHeadersCmd(peer, h)
case CMDInv:
inventory := msg.Payload.(*payload.Inventory)
return s.handleInvCmd(peer, inventory)
case CMDMempool:
// no payload
return s.handleMempoolCmd(peer)
case CMDBlock:
block := msg.Payload.(*block.Block)
return s.handleBlockCmd(peer, block)
case CMDExtensible:
cp := msg.Payload.(*payload.Extensible)
return s.handleExtensibleCmd(cp)
case CMDTX:
tx := msg.Payload.(*transaction.Transaction)
return s.handleTxCmd(tx)
case CMDP2PNotaryRequest:
r := msg.Payload.(*payload.P2PNotaryRequest)
return s.handleP2PNotaryRequestCmd(r)
case CMDPing:
ping := msg.Payload.(*payload.Ping)
return s.handlePing(peer, ping)
case CMDPong:
pong := msg.Payload.(*payload.Ping)
return s.handlePong(peer, pong)
case CMDVersion, CMDVerack:
return fmt.Errorf("received '%s' after the handshake", msg.Command.String())
}
} else {
switch msg.Command {
case CMDVersion:
version := msg.Payload.(*payload.Version)
return s.handleVersionCmd(peer, version)
case CMDVerack:
err := peer.HandleVersionAck()
if err != nil {
return err
}
go peer.StartProtocol()
s.tryInitStateSync()
s.tryStartServices()
default:
return fmt.Errorf("received '%s' during handshake", msg.Command.String())
}
}
return nil
}
func (s *Server) tryInitStateSync() {
if !s.stateSync.IsActive() {
s.bSyncQueue.discard()
return
}
if s.stateSync.IsInitialized() {
return
}
var peersNumber int
s.lock.RLock()
heights := make([]uint32, 0)
for p := range s.peers {
if p.Handshaked() {
peersNumber++
peerLastBlock := p.LastBlockIndex()
i := sort.Search(len(heights), func(i int) bool {
return heights[i] >= peerLastBlock
})
heights = append(heights, peerLastBlock)
if i != len(heights)-1 {
copy(heights[i+1:], heights[i:])
heights[i] = peerLastBlock
}
}
}
s.lock.RUnlock()
if peersNumber >= s.MinPeers && len(heights) > 0 {
// choose the height of the median peer as the current chain's height
h := heights[len(heights)/2]
err := s.stateSync.Init(h)
if err != nil {
s.log.Fatal("failed to init state sync module",
zap.Uint32("evaluated chain's blockHeight", h),
zap.Uint32("blockHeight", s.chain.BlockHeight()),
zap.Uint32("headerHeight", s.chain.HeaderHeight()),
zap.Error(err))
}
// module can be inactive after init (i.e. full state is collected and ordinary block processing is needed)
if !s.stateSync.IsActive() {
s.bSyncQueue.discard()
}
}
}
// BroadcastExtensible add a locally-generated Extensible payload to the pool
// and advertises it to peers.
func (s *Server) BroadcastExtensible(p *payload.Extensible) {
_, err := s.extensiblePool.Add(p)
if err != nil {
s.log.Error("created payload is not valid", zap.Error(err))
return
}
s.advertiseExtensible(p)
}
// RequestTx asks for the given transactions from Server peers using GetData message.
func (s *Server) RequestTx(hashes ...util.Uint256) {
if len(hashes) == 0 {
return
}
for i := 0; i <= len(hashes)/payload.MaxHashesCount; i++ {
start := i * payload.MaxHashesCount
stop := (i + 1) * payload.MaxHashesCount
if stop > len(hashes) {
stop = len(hashes)
}
if start == stop {
break
}
msg := NewMessage(CMDGetData, payload.NewInventory(payload.TXType, hashes[start:stop]))
// It's high priority because it directly affects consensus process,
// even though it's getdata.
s.broadcastHPMessage(msg)
}
}
// iteratePeersWithSendMsg sends the given message to all peers using two functions
// passed, one is to send the message and the other is to filtrate peers (the
// peer is considered invalid if it returns false).
func (s *Server) iteratePeersWithSendMsg(msg *Message, send func(Peer, bool, []byte) error, peerOK func(Peer) bool) {
var deadN, peerN, sentN int
// Get a copy of s.peers to avoid holding a lock while sending.
peers := s.getPeers(peerOK)
peerN = len(peers)
if peerN == 0 {
return
}
mrand.Shuffle(peerN, func(i, j int) {
peers[i], peers[j] = peers[j], peers[i]
})
pkt, err := msg.Bytes()
if err != nil {
return
}
// If true, this node isn't counted any more, either it's dead or we
// have already sent an Inv to it.
finished := make([]bool, peerN)
// Try non-blocking sends first and only block if have to.
for _, blocking := range []bool{false, true} {
for i, peer := range peers {
// Send to 2/3 of good peers.
if 3*sentN >= 2*(peerN-deadN) {
return
}
if finished[i] {
continue
}
err := send(peer, blocking, pkt)
switch err {
case nil:
if msg.Command == CMDGetAddr {
peer.AddGetAddrSent()
}
sentN++
case errBusy: // Can be retried.
continue
default:
deadN++
}
finished[i] = true
}
}
}
// broadcastMessage sends the message to all available peers.
func (s *Server) broadcastMessage(msg *Message) {
s.iteratePeersWithSendMsg(msg, Peer.EnqueuePacket, nil)
}
// broadcastHPMessage sends the high-priority message to all available peers.
func (s *Server) broadcastHPMessage(msg *Message) {
s.iteratePeersWithSendMsg(msg, Peer.EnqueueHPPacket, nil)
}
// relayBlocksLoop subscribes to new blocks in the ledger and broadcasts them
// to the network. Intended to be run as a separate goroutine.
func (s *Server) relayBlocksLoop() {
ch := make(chan *block.Block, 2) // Some buffering to smooth out possible egressing delays.
s.chain.SubscribeForBlocks(ch)
mainloop:
for {
select {
case <-s.quit:
s.chain.UnsubscribeFromBlocks(ch)
break mainloop
case b := <-ch:
msg := NewMessage(CMDInv, payload.NewInventory(payload.BlockType, []util.Uint256{b.Hash()}))
// Filter out nodes that are more current (avoid spamming the network
// during initial sync).
s.iteratePeersWithSendMsg(msg, Peer.EnqueuePacket, func(p Peer) bool {
return p.Handshaked() && p.LastBlockIndex() < b.Index
})
s.extensiblePool.RemoveStale(b.Index)
}
}
drainBlocksLoop:
for {
select {
case <-ch:
default:
break drainBlocksLoop
}
}
close(ch)
close(s.relayFin)
}
// verifyAndPoolTX verifies the TX and adds it to the local mempool.
func (s *Server) verifyAndPoolTX(t *transaction.Transaction) error {
return s.chain.PoolTx(t)
}
// RelayTxn a new transaction to the local node and the connected peers.
// Reference: the method OnRelay in C#: https://github.com/neo-project/neo/blob/master/neo/Network/P2P/LocalNode.cs#L159
func (s *Server) RelayTxn(t *transaction.Transaction) error {
err := s.verifyAndPoolTX(t)
if err == nil {
s.broadcastTX(t, nil)
}
return err
}
// broadcastTX broadcasts an inventory message about new transaction.
func (s *Server) broadcastTX(t *transaction.Transaction, _ interface{}) {
select {
case s.transactions <- t:
case <-s.quit:
}
}
func (s *Server) broadcastTxHashes(hs []util.Uint256) {
msg := NewMessage(CMDInv, payload.NewInventory(payload.TXType, hs))
// We need to filter out non-relaying nodes, so plain broadcast
// functions don't fit here.
s.iteratePeersWithSendMsg(msg, Peer.EnqueuePacket, Peer.IsFullNode)
}
// initStaleMemPools initializes mempools for stale tx/payload processing.
func (s *Server) initStaleMemPools() {
threshold := 5
// Not perfect, can change over time, but should be sufficient.
numOfCNs := s.config.GetNumOfCNs(s.chain.BlockHeight())
if numOfCNs*2 > threshold {
threshold = numOfCNs * 2
}
s.mempool.SetResendThreshold(uint32(threshold), s.broadcastTX)
if s.chain.P2PSigExtensionsEnabled() {
s.notaryRequestPool.SetResendThreshold(uint32(threshold), s.broadcastP2PNotaryRequestPayload)
}
}
// broadcastTxLoop is a loop for batching and sending
// transactions hashes in an INV payload.
func (s *Server) broadcastTxLoop() {
const (
batchTime = time.Millisecond * 50
batchSize = 32
)
txs := make([]util.Uint256, 0, batchSize)
var timer *time.Timer
timerCh := func() <-chan time.Time {
if timer == nil {
return nil
}
return timer.C
}
broadcast := func() {
s.broadcastTxHashes(txs)
txs = txs[:0]
if timer != nil {
timer.Stop()
}
}
for {
select {
case <-s.quit:
loop:
for {
select {
case <-s.transactions:
default:
break loop
}
}
return
case <-timerCh():
if len(txs) > 0 {
broadcast()
}
case tx := <-s.transactions:
if len(txs) == 0 {
timer = time.NewTimer(batchTime)
}
txs = append(txs, tx.Hash())
if len(txs) == batchSize {
broadcast()
}
}
}
}
// Port returns a server port that should be used in P2P version exchange. In
// case `AnnouncedPort` is set in the server.Config, the announced node port
// will be returned (e.g. consider the node running behind NAT). If `AnnouncedPort`
// isn't set, the port returned may still differs from that of server.Config.
func (s *Server) Port() (uint16, error) {
if s.AnnouncedPort != 0 {
return s.ServerConfig.AnnouncedPort, nil
}
var port uint16
_, portStr, err := net.SplitHostPort(s.transport.Address())
if err != nil {
port = s.ServerConfig.Port
} else {
p, err := strconv.ParseUint(portStr, 10, 16)
if err != nil {
return 0, err
}
port = uint16(p)
}
return port, nil
}