neo-go/pkg/network/tcp_peer.go
Roman Khimov fdbaac7a30 network: prevent broadcast queue starving, share time with p2p
Blocked broadcast queue of one peer may affect broadcasting capabilities of
the server, so prevent total blocking of it by p2p queue.
2020-01-30 14:03:52 +03:00

411 lines
10 KiB
Go

package network
import (
"errors"
"fmt"
"net"
"strconv"
"sync"
"time"
"github.com/CityOfZion/neo-go/pkg/io"
"github.com/CityOfZion/neo-go/pkg/network/payload"
"go.uber.org/zap"
)
type handShakeStage uint8
const (
versionSent handShakeStage = 1 << iota
versionReceived
verAckSent
verAckReceived
requestQueueSize = 32
p2pMsgQueueSize = 16
hpRequestQueueSize = 4
)
var (
errStateMismatch = errors.New("tried to send protocol message before handshake completed")
errPingPong = errors.New("ping/pong timeout")
errUnexpectedPong = errors.New("pong message wasn't expected")
)
// TCPPeer represents a connected remote node in the
// network over TCP.
type TCPPeer struct {
// underlying TCP connection.
conn net.Conn
// The server this peer belongs to.
server *Server
// The version of the peer.
version *payload.Version
// Index of the last block.
lastBlockIndex uint32
lock sync.RWMutex
finale sync.Once
handShake handShakeStage
done chan struct{}
sendQ chan []byte
p2pSendQ chan []byte
hpSendQ chan []byte
wg sync.WaitGroup
// number of sent pings.
pingSent int
pingTimer *time.Timer
}
// NewTCPPeer returns a TCPPeer structure based on the given connection.
func NewTCPPeer(conn net.Conn, s *Server) *TCPPeer {
return &TCPPeer{
conn: conn,
server: s,
done: make(chan struct{}),
sendQ: make(chan []byte, requestQueueSize),
p2pSendQ: make(chan []byte, p2pMsgQueueSize),
hpSendQ: make(chan []byte, hpRequestQueueSize),
}
}
// putPacketIntoQueue puts given message into the given queue if the peer has
// done handshaking.
func (p *TCPPeer) putPacketIntoQueue(queue chan<- []byte, msg []byte) error {
if !p.Handshaked() {
return errStateMismatch
}
queue <- msg
return nil
}
// EnqueuePacket implements the Peer interface.
func (p *TCPPeer) EnqueuePacket(msg []byte) error {
return p.putPacketIntoQueue(p.sendQ, msg)
}
// putMessageIntoQueue serializes given Message and puts it into given queue if
// the peer has done handshaking.
func (p *TCPPeer) putMsgIntoQueue(queue chan<- []byte, msg *Message) error {
b, err := msg.Bytes()
if err != nil {
return err
}
return p.putPacketIntoQueue(queue, b)
}
// EnqueueMessage is a temporary wrapper that sends a message via
// EnqueuePacket if there is no error in serializing it.
func (p *TCPPeer) EnqueueMessage(msg *Message) error {
return p.putMsgIntoQueue(p.sendQ, msg)
}
// EnqueueP2PPacket implements the Peer interface.
func (p *TCPPeer) EnqueueP2PPacket(msg []byte) error {
return p.putPacketIntoQueue(p.p2pSendQ, msg)
}
// EnqueueP2PMessage implements the Peer interface.
func (p *TCPPeer) EnqueueP2PMessage(msg *Message) error {
return p.putMsgIntoQueue(p.p2pSendQ, msg)
}
// EnqueueHPPacket implements the Peer interface. It the peer is not yet
// handshaked it's a noop.
func (p *TCPPeer) EnqueueHPPacket(msg []byte) error {
return p.putPacketIntoQueue(p.hpSendQ, msg)
}
func (p *TCPPeer) writeMsg(msg *Message) error {
b, err := msg.Bytes()
if err != nil {
return err
}
_, err = p.conn.Write(b)
return err
}
// handleConn handles the read side of the connection, it should be started as
// a goroutine right after the new peer setup.
func (p *TCPPeer) handleConn() {
var err error
p.server.register <- p
go p.handleQueues()
// When a new peer is connected we send out our version immediately.
err = p.SendVersion()
if err == nil {
r := io.NewBinReaderFromIO(p.conn)
for {
msg := &Message{}
err = msg.Decode(r)
if err == payload.ErrTooManyHeaders {
p.server.log.Warn("not all headers were processed")
r.Err = nil
} else if err != nil {
break
}
if err = p.server.handleMessage(p, msg); err != nil {
if p.Handshaked() {
err = fmt.Errorf("handling %s message: %v", msg.CommandType(), err)
}
break
}
}
}
p.Disconnect(err)
}
// handleQueues is a goroutine that is started automatically to handle
// send queues.
func (p *TCPPeer) handleQueues() {
var err error
// p2psend queue shares its time with send queue in around
// ((p2pSkipDivisor - 1) * 2 + 1)/1 ratio, ratio because the third
// select can still choose p2psend over send.
var p2pSkipCounter uint32
const p2pSkipDivisor = 4
for {
var msg []byte
// This one is to give priority to the hp queue
select {
case <-p.done:
return
case msg = <-p.hpSendQ:
default:
}
// Skip this select every p2pSkipDivisor iteration.
if msg == nil && p2pSkipCounter%p2pSkipDivisor != 0 {
// Then look at the p2p queue.
select {
case <-p.done:
return
case msg = <-p.hpSendQ:
case msg = <-p.p2pSendQ:
default:
}
}
// If there is no message in HP or P2P queues, block until one
// appears in any of the queues.
if msg == nil {
select {
case <-p.done:
return
case msg = <-p.hpSendQ:
case msg = <-p.p2pSendQ:
case msg = <-p.sendQ:
}
}
_, err = p.conn.Write(msg)
if err != nil {
break
}
p2pSkipCounter++
}
p.Disconnect(err)
}
// StartProtocol starts a long running background loop that interacts
// every ProtoTickInterval with the peer. It's only good to run after the
// handshake.
func (p *TCPPeer) StartProtocol() {
var err error
p.server.log.Info("started protocol",
zap.Stringer("addr", p.RemoteAddr()),
zap.ByteString("userAgent", p.Version().UserAgent),
zap.Uint32("startHeight", p.Version().StartHeight),
zap.Uint32("id", p.Version().Nonce))
p.server.discovery.RegisterGoodAddr(p.PeerAddr().String())
if p.server.chain.HeaderHeight() < p.LastBlockIndex() {
err = p.server.requestHeaders(p)
if err != nil {
p.Disconnect(err)
return
}
}
timer := time.NewTimer(p.server.ProtoTickInterval)
for {
select {
case <-p.done:
return
case <-timer.C:
// Try to sync in headers and block with the peer if his block height is higher then ours.
if p.LastBlockIndex() > p.server.chain.BlockHeight() {
err = p.server.requestBlocks(p)
}
if err == nil {
timer.Reset(p.server.ProtoTickInterval)
}
}
if err != nil {
timer.Stop()
p.Disconnect(err)
return
}
}
}
// Handshaked returns status of the handshake, whether it's completed or not.
func (p *TCPPeer) Handshaked() bool {
p.lock.RLock()
defer p.lock.RUnlock()
return p.handShake == (verAckReceived | verAckSent | versionReceived | versionSent)
}
// SendVersion checks for the handshake state and sends a message to the peer.
func (p *TCPPeer) SendVersion() error {
msg := p.server.getVersionMsg()
p.lock.Lock()
defer p.lock.Unlock()
if p.handShake&versionSent != 0 {
return errors.New("invalid handshake: already sent Version")
}
err := p.writeMsg(msg)
if err == nil {
p.handShake |= versionSent
}
return err
}
// HandleVersion checks for the handshake state and version message contents.
func (p *TCPPeer) HandleVersion(version *payload.Version) error {
p.lock.Lock()
defer p.lock.Unlock()
if p.handShake&versionReceived != 0 {
return errors.New("invalid handshake: already received Version")
}
p.version = version
p.lastBlockIndex = version.StartHeight
p.handShake |= versionReceived
return nil
}
// SendVersionAck checks for the handshake state and sends a message to the peer.
func (p *TCPPeer) SendVersionAck(msg *Message) error {
p.lock.Lock()
defer p.lock.Unlock()
if p.handShake&versionReceived == 0 {
return errors.New("invalid handshake: tried to send VersionAck, but no version received yet")
}
if p.handShake&versionSent == 0 {
return errors.New("invalid handshake: tried to send VersionAck, but didn't send Version yet")
}
if p.handShake&verAckSent != 0 {
return errors.New("invalid handshake: already sent VersionAck")
}
err := p.writeMsg(msg)
if err == nil {
p.handShake |= verAckSent
}
return err
}
// HandleVersionAck checks handshake sequence correctness when VerAck message
// is received.
func (p *TCPPeer) HandleVersionAck() error {
p.lock.Lock()
defer p.lock.Unlock()
if p.handShake&versionSent == 0 {
return errors.New("invalid handshake: received VersionAck, but no version sent yet")
}
if p.handShake&versionReceived == 0 {
return errors.New("invalid handshake: received VersionAck, but no version received yet")
}
if p.handShake&verAckReceived != 0 {
return errors.New("invalid handshake: already received VersionAck")
}
p.handShake |= verAckReceived
return nil
}
// RemoteAddr implements the Peer interface.
func (p *TCPPeer) RemoteAddr() net.Addr {
return p.conn.RemoteAddr()
}
// PeerAddr implements the Peer interface.
func (p *TCPPeer) PeerAddr() net.Addr {
remote := p.conn.RemoteAddr()
// The network can be non-tcp in unit tests.
if p.version == nil || remote.Network() != "tcp" {
return p.RemoteAddr()
}
host, _, err := net.SplitHostPort(remote.String())
if err != nil {
return p.RemoteAddr()
}
addrString := net.JoinHostPort(host, strconv.Itoa(int(p.version.Port)))
tcpAddr, err := net.ResolveTCPAddr("tcp", addrString)
if err != nil {
return p.RemoteAddr()
}
return tcpAddr
}
// Disconnect will fill the peer's done channel with the given error.
func (p *TCPPeer) Disconnect(err error) {
p.finale.Do(func() {
p.server.unregister <- peerDrop{p, err}
p.conn.Close()
close(p.done)
})
}
// Version implements the Peer interface.
func (p *TCPPeer) Version() *payload.Version {
return p.version
}
// LastBlockIndex returns last block index.
func (p *TCPPeer) LastBlockIndex() uint32 {
p.lock.RLock()
defer p.lock.RUnlock()
return p.lastBlockIndex
}
// SendPing sends a ping message to the peer and does appropriate accounting of
// outstanding pings and timeouts.
func (p *TCPPeer) SendPing(msg *Message) error {
if !p.Handshaked() {
return errStateMismatch
}
p.lock.Lock()
p.pingSent++
if p.pingTimer == nil {
p.pingTimer = time.AfterFunc(p.server.PingTimeout, func() {
p.Disconnect(errPingPong)
})
}
p.lock.Unlock()
return p.EnqueueMessage(msg)
}
// HandlePong handles a pong message received from the peer and does appropriate
// accounting of outstanding pings and timeouts.
func (p *TCPPeer) HandlePong(pong *payload.Ping) error {
p.lock.Lock()
defer p.lock.Unlock()
if p.pingTimer != nil && !p.pingTimer.Stop() {
return errPingPong
}
p.pingTimer = nil
p.pingSent--
if p.pingSent < 0 {
return errUnexpectedPong
}
p.lastBlockIndex = pong.LastBlockIndex
return nil
}