mirror of
https://github.com/nspcc-dev/neo-go.git
synced 2024-12-05 03:58:23 +00:00
416 lines
10 KiB
Go
416 lines
10 KiB
Go
package network
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import (
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"errors"
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"fmt"
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"net"
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"strconv"
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"sync"
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"time"
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"github.com/nspcc-dev/neo-go/pkg/io"
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"github.com/nspcc-dev/neo-go/pkg/network/payload"
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"go.uber.org/zap"
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)
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type handShakeStage uint8
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const (
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versionSent handShakeStage = 1 << iota
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versionReceived
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verAckSent
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verAckReceived
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requestQueueSize = 32
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p2pMsgQueueSize = 16
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hpRequestQueueSize = 4
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)
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var (
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errGone = errors.New("the peer is gone already")
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errStateMismatch = errors.New("tried to send protocol message before handshake completed")
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errPingPong = errors.New("ping/pong timeout")
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errUnexpectedPong = errors.New("pong message wasn't expected")
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)
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// TCPPeer represents a connected remote node in the
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// network over TCP.
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type TCPPeer struct {
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// underlying TCP connection.
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conn net.Conn
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// The server this peer belongs to.
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server *Server
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// The version of the peer.
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version *payload.Version
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// Index of the last block.
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lastBlockIndex uint32
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lock sync.RWMutex
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finale sync.Once
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handShake handShakeStage
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done chan struct{}
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sendQ chan []byte
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p2pSendQ chan []byte
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hpSendQ chan []byte
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wg sync.WaitGroup
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// number of sent pings.
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pingSent int
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pingTimer *time.Timer
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}
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// NewTCPPeer returns a TCPPeer structure based on the given connection.
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func NewTCPPeer(conn net.Conn, s *Server) *TCPPeer {
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return &TCPPeer{
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conn: conn,
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server: s,
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done: make(chan struct{}),
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sendQ: make(chan []byte, requestQueueSize),
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p2pSendQ: make(chan []byte, p2pMsgQueueSize),
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hpSendQ: make(chan []byte, hpRequestQueueSize),
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}
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}
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// putPacketIntoQueue puts given message into the given queue if the peer has
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// done handshaking.
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func (p *TCPPeer) putPacketIntoQueue(queue chan<- []byte, msg []byte) error {
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if !p.Handshaked() {
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return errStateMismatch
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}
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select {
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case queue <- msg:
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case <-p.done:
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return errGone
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}
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return nil
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}
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// EnqueuePacket implements the Peer interface.
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func (p *TCPPeer) EnqueuePacket(msg []byte) error {
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return p.putPacketIntoQueue(p.sendQ, msg)
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}
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// putMessageIntoQueue serializes given Message and puts it into given queue if
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// the peer has done handshaking.
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func (p *TCPPeer) putMsgIntoQueue(queue chan<- []byte, msg *Message) error {
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b, err := msg.Bytes()
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if err != nil {
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return err
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}
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return p.putPacketIntoQueue(queue, b)
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}
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// EnqueueMessage is a temporary wrapper that sends a message via
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// EnqueuePacket if there is no error in serializing it.
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func (p *TCPPeer) EnqueueMessage(msg *Message) error {
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return p.putMsgIntoQueue(p.sendQ, msg)
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}
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// EnqueueP2PPacket implements the Peer interface.
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func (p *TCPPeer) EnqueueP2PPacket(msg []byte) error {
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return p.putPacketIntoQueue(p.p2pSendQ, msg)
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}
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// EnqueueP2PMessage implements the Peer interface.
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func (p *TCPPeer) EnqueueP2PMessage(msg *Message) error {
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return p.putMsgIntoQueue(p.p2pSendQ, msg)
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}
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// EnqueueHPPacket implements the Peer interface. It the peer is not yet
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// handshaked it's a noop.
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func (p *TCPPeer) EnqueueHPPacket(msg []byte) error {
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return p.putPacketIntoQueue(p.hpSendQ, msg)
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}
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func (p *TCPPeer) writeMsg(msg *Message) error {
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b, err := msg.Bytes()
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if err != nil {
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return err
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}
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_, err = p.conn.Write(b)
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return err
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}
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// handleConn handles the read side of the connection, it should be started as
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// a goroutine right after the new peer setup.
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func (p *TCPPeer) handleConn() {
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var err error
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p.server.register <- p
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go p.handleQueues()
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// When a new peer is connected we send out our version immediately.
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err = p.SendVersion()
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if err == nil {
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r := io.NewBinReaderFromIO(p.conn)
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for {
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msg := &Message{}
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err = msg.Decode(r)
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if err == payload.ErrTooManyHeaders {
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p.server.log.Warn("not all headers were processed")
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r.Err = nil
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} else if err != nil {
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break
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}
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if err = p.server.handleMessage(p, msg); err != nil {
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if p.Handshaked() {
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err = fmt.Errorf("handling %s message: %v", msg.CommandType(), err)
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}
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break
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}
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}
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}
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p.Disconnect(err)
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}
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// handleQueues is a goroutine that is started automatically to handle
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// send queues.
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func (p *TCPPeer) handleQueues() {
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var err error
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// p2psend queue shares its time with send queue in around
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// ((p2pSkipDivisor - 1) * 2 + 1)/1 ratio, ratio because the third
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// select can still choose p2psend over send.
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var p2pSkipCounter uint32
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const p2pSkipDivisor = 4
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for {
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var msg []byte
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// This one is to give priority to the hp queue
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select {
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case <-p.done:
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return
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case msg = <-p.hpSendQ:
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default:
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}
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// Skip this select every p2pSkipDivisor iteration.
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if msg == nil && p2pSkipCounter%p2pSkipDivisor != 0 {
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// Then look at the p2p queue.
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select {
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case <-p.done:
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return
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case msg = <-p.hpSendQ:
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case msg = <-p.p2pSendQ:
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default:
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}
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}
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// If there is no message in HP or P2P queues, block until one
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// appears in any of the queues.
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if msg == nil {
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select {
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case <-p.done:
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return
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case msg = <-p.hpSendQ:
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case msg = <-p.p2pSendQ:
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case msg = <-p.sendQ:
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}
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}
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_, err = p.conn.Write(msg)
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if err != nil {
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break
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}
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p2pSkipCounter++
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}
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p.Disconnect(err)
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}
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// StartProtocol starts a long running background loop that interacts
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// every ProtoTickInterval with the peer. It's only good to run after the
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// handshake.
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func (p *TCPPeer) StartProtocol() {
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var err error
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p.server.log.Info("started protocol",
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zap.Stringer("addr", p.RemoteAddr()),
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zap.ByteString("userAgent", p.Version().UserAgent),
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zap.Uint32("startHeight", p.Version().StartHeight),
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zap.Uint32("id", p.Version().Nonce))
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p.server.discovery.RegisterGoodAddr(p.PeerAddr().String())
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if p.server.chain.HeaderHeight() < p.LastBlockIndex() {
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err = p.server.requestHeaders(p)
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if err != nil {
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p.Disconnect(err)
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return
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}
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}
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timer := time.NewTimer(p.server.ProtoTickInterval)
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for {
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select {
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case <-p.done:
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return
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case <-timer.C:
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// Try to sync in headers and block with the peer if his block height is higher then ours.
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if p.LastBlockIndex() > p.server.chain.BlockHeight() {
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err = p.server.requestBlocks(p)
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}
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if err == nil {
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timer.Reset(p.server.ProtoTickInterval)
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}
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}
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if err != nil {
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timer.Stop()
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p.Disconnect(err)
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return
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}
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}
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}
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// Handshaked returns status of the handshake, whether it's completed or not.
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func (p *TCPPeer) Handshaked() bool {
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p.lock.RLock()
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defer p.lock.RUnlock()
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return p.handShake == (verAckReceived | verAckSent | versionReceived | versionSent)
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}
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// SendVersion checks for the handshake state and sends a message to the peer.
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func (p *TCPPeer) SendVersion() error {
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msg := p.server.getVersionMsg()
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p.lock.Lock()
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defer p.lock.Unlock()
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if p.handShake&versionSent != 0 {
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return errors.New("invalid handshake: already sent Version")
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}
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err := p.writeMsg(msg)
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if err == nil {
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p.handShake |= versionSent
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}
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return err
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}
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// HandleVersion checks for the handshake state and version message contents.
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func (p *TCPPeer) HandleVersion(version *payload.Version) error {
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p.lock.Lock()
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defer p.lock.Unlock()
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if p.handShake&versionReceived != 0 {
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return errors.New("invalid handshake: already received Version")
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}
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p.version = version
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p.lastBlockIndex = version.StartHeight
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p.handShake |= versionReceived
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return nil
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}
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// SendVersionAck checks for the handshake state and sends a message to the peer.
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func (p *TCPPeer) SendVersionAck(msg *Message) error {
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p.lock.Lock()
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defer p.lock.Unlock()
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if p.handShake&versionReceived == 0 {
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return errors.New("invalid handshake: tried to send VersionAck, but no version received yet")
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}
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if p.handShake&versionSent == 0 {
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return errors.New("invalid handshake: tried to send VersionAck, but didn't send Version yet")
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}
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if p.handShake&verAckSent != 0 {
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return errors.New("invalid handshake: already sent VersionAck")
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}
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err := p.writeMsg(msg)
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if err == nil {
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p.handShake |= verAckSent
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}
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return err
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}
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// HandleVersionAck checks handshake sequence correctness when VerAck message
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// is received.
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func (p *TCPPeer) HandleVersionAck() error {
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p.lock.Lock()
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defer p.lock.Unlock()
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if p.handShake&versionSent == 0 {
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return errors.New("invalid handshake: received VersionAck, but no version sent yet")
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}
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if p.handShake&versionReceived == 0 {
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return errors.New("invalid handshake: received VersionAck, but no version received yet")
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}
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if p.handShake&verAckReceived != 0 {
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return errors.New("invalid handshake: already received VersionAck")
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}
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p.handShake |= verAckReceived
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return nil
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}
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// RemoteAddr implements the Peer interface.
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func (p *TCPPeer) RemoteAddr() net.Addr {
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return p.conn.RemoteAddr()
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}
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// PeerAddr implements the Peer interface.
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func (p *TCPPeer) PeerAddr() net.Addr {
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remote := p.conn.RemoteAddr()
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// The network can be non-tcp in unit tests.
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if p.version == nil || remote.Network() != "tcp" {
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return p.RemoteAddr()
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}
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host, _, err := net.SplitHostPort(remote.String())
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if err != nil {
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return p.RemoteAddr()
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}
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addrString := net.JoinHostPort(host, strconv.Itoa(int(p.version.Port)))
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tcpAddr, err := net.ResolveTCPAddr("tcp", addrString)
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if err != nil {
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return p.RemoteAddr()
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}
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return tcpAddr
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}
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// Disconnect will fill the peer's done channel with the given error.
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func (p *TCPPeer) Disconnect(err error) {
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p.finale.Do(func() {
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close(p.done)
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p.conn.Close()
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p.server.unregister <- peerDrop{p, err}
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})
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}
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// Version implements the Peer interface.
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func (p *TCPPeer) Version() *payload.Version {
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return p.version
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}
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// LastBlockIndex returns last block index.
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func (p *TCPPeer) LastBlockIndex() uint32 {
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p.lock.RLock()
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defer p.lock.RUnlock()
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return p.lastBlockIndex
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}
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// SendPing sends a ping message to the peer and does appropriate accounting of
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// outstanding pings and timeouts.
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func (p *TCPPeer) SendPing(msg *Message) error {
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if !p.Handshaked() {
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return errStateMismatch
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}
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p.lock.Lock()
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p.pingSent++
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if p.pingTimer == nil {
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p.pingTimer = time.AfterFunc(p.server.PingTimeout, func() {
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p.Disconnect(errPingPong)
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})
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}
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p.lock.Unlock()
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return p.EnqueueMessage(msg)
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}
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// HandlePong handles a pong message received from the peer and does appropriate
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// accounting of outstanding pings and timeouts.
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func (p *TCPPeer) HandlePong(pong *payload.Ping) error {
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p.lock.Lock()
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defer p.lock.Unlock()
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if p.pingTimer != nil && !p.pingTimer.Stop() {
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return errPingPong
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}
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p.pingTimer = nil
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p.pingSent--
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if p.pingSent < 0 {
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return errUnexpectedPong
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}
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p.lastBlockIndex = pong.LastBlockIndex
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return nil
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}
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