773ccc2b92
...and don't try to connect to the nodes we're already connected to. Before this change we had a problem of discoverer throwing away good valid addresses just because they are already known which lead to pool draining over time (as address reuse was basically forbidden and getaddr may not get enough new nodes).
412 lines
11 KiB
Go
412 lines
11 KiB
Go
package network
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import (
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"errors"
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"fmt"
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"math/rand"
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"sync"
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"time"
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"github.com/CityOfZion/neo-go/pkg/core"
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"github.com/CityOfZion/neo-go/pkg/core/transaction"
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"github.com/CityOfZion/neo-go/pkg/network/payload"
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"github.com/CityOfZion/neo-go/pkg/util"
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log "github.com/sirupsen/logrus"
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)
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const (
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// peer numbers are arbitrary at the moment
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minPeers = 5
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maxPeers = 20
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maxBlockBatch = 200
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minPoolCount = 30
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)
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var (
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errPortMismatch = errors.New("port mismatch")
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errIdenticalID = errors.New("identical node id")
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errInvalidHandshake = errors.New("invalid handshake")
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errInvalidNetwork = errors.New("invalid network")
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errServerShutdown = errors.New("server shutdown")
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errInvalidInvType = errors.New("invalid inventory type")
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)
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type (
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// Server represents the local Node in the network. Its transport could
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// be of any kind.
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Server struct {
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// ServerConfig holds the Server configuration.
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ServerConfig
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// id also known as the nonce of the server.
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id uint32
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transport Transporter
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discovery Discoverer
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chain core.Blockchainer
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lock sync.RWMutex
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peers map[Peer]bool
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addrReq chan *Message
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register chan Peer
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unregister chan peerDrop
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quit chan struct{}
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}
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peerDrop struct {
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peer Peer
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reason error
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}
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)
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// NewServer returns a new Server, initialized with the given configuration.
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func NewServer(config ServerConfig, chain core.Blockchainer) *Server {
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s := &Server{
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ServerConfig: config,
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chain: chain,
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id: rand.Uint32(),
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quit: make(chan struct{}),
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addrReq: make(chan *Message, minPeers),
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register: make(chan Peer),
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unregister: make(chan peerDrop),
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peers: make(map[Peer]bool),
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}
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s.transport = NewTCPTransport(s, fmt.Sprintf(":%d", config.ListenTCP))
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s.discovery = NewDefaultDiscovery(
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s.DialTimeout,
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s.transport,
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)
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return s
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}
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// ID returns the servers ID.
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func (s *Server) ID() uint32 {
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return s.id
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}
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// Start will start the server and its underlying transport.
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func (s *Server) Start(errChan chan error) {
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log.WithFields(log.Fields{
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"blockHeight": s.chain.BlockHeight(),
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"headerHeight": s.chain.HeaderHeight(),
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}).Info("node started")
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s.discovery.BackFill(s.Seeds...)
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go s.transport.Accept()
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s.run()
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}
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// Shutdown disconnects all peers and stops listening.
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func (s *Server) Shutdown() {
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log.WithFields(log.Fields{
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"peers": s.PeerCount(),
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}).Info("shutting down server")
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close(s.quit)
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}
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// UnconnectedPeers returns a list of peers that are in the discovery peer list
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// but are not connected to the server.
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func (s *Server) UnconnectedPeers() []string {
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return []string{}
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}
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// BadPeers returns a list of peers the are flagged as "bad" peers.
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func (s *Server) BadPeers() []string {
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return []string{}
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}
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func (s *Server) run() {
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for {
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c := s.PeerCount()
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if c < minPeers {
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s.discovery.RequestRemote(maxPeers - c)
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}
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if s.discovery.PoolCount() < minPoolCount {
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select {
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case s.addrReq <- NewMessage(s.Net, CMDGetAddr, payload.NewNullPayload()):
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// sent request
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default:
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// we have one in the queue already that is
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// gonna be served by some worker when it's ready
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}
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}
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select {
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case <-s.quit:
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s.transport.Close()
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for p := range s.peers {
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p.Disconnect(errServerShutdown)
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}
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return
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case p := <-s.register:
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// When a new peer is connected we send out our version immediately.
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if err := s.sendVersion(p); err != nil {
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log.WithFields(log.Fields{
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"addr": p.NetAddr(),
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}).Error(err)
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}
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s.peers[p] = true
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log.WithFields(log.Fields{
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"addr": p.NetAddr(),
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}).Info("new peer connected")
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case drop := <-s.unregister:
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if s.peers[drop.peer] {
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delete(s.peers, drop.peer)
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log.WithFields(log.Fields{
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"addr": drop.peer.NetAddr(),
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"reason": drop.reason,
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"peerCount": s.PeerCount(),
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}).Warn("peer disconnected")
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addr := drop.peer.NetAddr().String()
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s.discovery.UnregisterConnectedAddr(addr)
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s.discovery.BackFill(addr)
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}
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// else the peer is already gone, which can happen
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// because we have two goroutines sending signals here
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}
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}
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}
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// Peers returns the current list of peers connected to
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// the server.
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func (s *Server) Peers() map[Peer]bool {
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return s.peers
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}
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// PeerCount returns the number of current connected peers.
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func (s *Server) PeerCount() int {
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s.lock.RLock()
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defer s.lock.RUnlock()
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return len(s.peers)
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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.
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func (s *Server) startProtocol(p Peer) {
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log.WithFields(log.Fields{
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"addr": p.NetAddr(),
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"userAgent": string(p.Version().UserAgent),
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"startHeight": p.Version().StartHeight,
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"id": p.Version().Nonce,
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}).Info("started protocol")
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s.discovery.RegisterGoodAddr(p.NetAddr().String())
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err := s.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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timer := time.NewTimer(s.ProtoTickInterval)
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for {
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select {
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case err = <-p.Done():
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// time to stop
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case m := <-s.addrReq:
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err = p.WriteMsg(m)
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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.Version().StartHeight > s.chain.BlockHeight() {
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err = s.requestBlocks(p)
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}
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if err == nil {
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timer.Reset(s.ProtoTickInterval)
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}
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}
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if err != nil {
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s.unregister <- peerDrop{p, err}
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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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// When a peer connects to the server, we will send our version immediately.
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func (s *Server) sendVersion(p Peer) error {
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payload := payload.NewVersion(
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s.id,
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s.ListenTCP,
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s.UserAgent,
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s.chain.BlockHeight(),
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s.Relay,
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)
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return p.SendVersion(NewMessage(s.Net, CMDVersion, payload))
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}
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// When a peer sends out his version we reply with verack after validating
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// the version.
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func (s *Server) handleVersionCmd(p Peer, version *payload.Version) error {
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err := p.HandleVersion(version)
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if err != nil {
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return err
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}
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if s.id == version.Nonce {
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return errIdenticalID
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}
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if p.NetAddr().Port != int(version.Port) {
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return errPortMismatch
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}
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return p.SendVersionAck(NewMessage(s.Net, CMDVerack, nil))
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}
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// handleHeadersCmd will process the headers it received from its peer.
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// if the headerHeight of the blockchain still smaller then the peer
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// the server will request more headers.
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// This method could best be called in a separate routine.
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func (s *Server) handleHeadersCmd(p Peer, headers *payload.Headers) {
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if err := s.chain.AddHeaders(headers.Hdrs...); err != nil {
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log.Warnf("failed processing headers: %s", err)
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return
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}
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// The peer will respond with a maximum of 2000 headers in one batch.
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// We will ask one more batch here if needed. Eventually we will get synced
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// due to the startProtocol routine that will ask headers every protoTick.
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if s.chain.HeaderHeight() < p.Version().StartHeight {
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s.requestHeaders(p)
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}
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}
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// handleBlockCmd processes the received block received from its peer.
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func (s *Server) handleBlockCmd(p Peer, block *core.Block) error {
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if !s.chain.HasBlock(block.Hash()) {
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return s.chain.AddBlock(block)
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}
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return nil
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}
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// handleInvCmd will process the received inventory.
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func (s *Server) handleInvCmd(p Peer, inv *payload.Inventory) error {
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if !inv.Type.Valid() || len(inv.Hashes) == 0 {
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return errInvalidInvType
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}
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payload := payload.NewInventory(inv.Type, inv.Hashes)
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return p.WriteMsg(NewMessage(s.Net, CMDGetData, payload))
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}
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// handleAddrCmd will process received addresses.
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func (s *Server) handleAddrCmd(p Peer, addrs *payload.AddressList) error {
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for _, a := range addrs.Addrs {
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s.discovery.BackFill(a.IPPortString())
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}
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return nil
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}
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// requestHeaders will send a getheaders message to the peer.
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// The peer will respond with headers op to a count of 2000.
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func (s *Server) requestHeaders(p Peer) error {
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start := []util.Uint256{s.chain.CurrentHeaderHash()}
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payload := payload.NewGetBlocks(start, util.Uint256{})
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return p.WriteMsg(NewMessage(s.Net, CMDGetHeaders, payload))
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}
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// requestBlocks will send a getdata message to the peer
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// to sync up in blocks. A maximum of maxBlockBatch will
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// send at once.
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func (s *Server) requestBlocks(p Peer) error {
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var (
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hashes []util.Uint256
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hashStart = s.chain.BlockHeight() + 1
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headerHeight = s.chain.HeaderHeight()
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)
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for hashStart < headerHeight && len(hashes) < maxBlockBatch {
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hash := s.chain.GetHeaderHash(int(hashStart))
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hashes = append(hashes, hash)
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hashStart++
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}
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if len(hashes) > 0 {
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payload := payload.NewInventory(payload.BlockType, hashes)
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return p.WriteMsg(NewMessage(s.Net, CMDGetData, payload))
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} else if s.chain.HeaderHeight() < p.Version().StartHeight {
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return s.requestHeaders(p)
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}
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return nil
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}
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// handleMessage will process the given message.
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func (s *Server) handleMessage(peer Peer, msg *Message) error {
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// Make sure both server and peer are operating on
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// the same network.
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if msg.Magic != s.Net {
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return errInvalidNetwork
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}
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if peer.Handshaked() {
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switch msg.CommandType() {
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case CMDAddr:
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addrs := msg.Payload.(*payload.AddressList)
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return s.handleAddrCmd(peer, addrs)
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case CMDHeaders:
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headers := msg.Payload.(*payload.Headers)
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go s.handleHeadersCmd(peer, headers)
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case CMDInv:
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inventory := msg.Payload.(*payload.Inventory)
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return s.handleInvCmd(peer, inventory)
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case CMDBlock:
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block := msg.Payload.(*core.Block)
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return s.handleBlockCmd(peer, block)
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case CMDVersion, CMDVerack:
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return fmt.Errorf("received '%s' after the handshake", msg.CommandType())
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}
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} else {
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switch msg.CommandType() {
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case CMDVersion:
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version := msg.Payload.(*payload.Version)
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return s.handleVersionCmd(peer, version)
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case CMDVerack:
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err := peer.HandleVersionAck()
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if err != nil {
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return err
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}
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go s.startProtocol(peer)
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default:
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return fmt.Errorf("received '%s' during handshake", msg.CommandType())
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}
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}
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return nil
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}
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// RelayTxn a new transaction to the local node and the connected peers.
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// Reference: the method OnRelay in C#: https://github.com/neo-project/neo/blob/master/neo/Network/P2P/LocalNode.cs#L159
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func (s *Server) RelayTxn(t *transaction.Transaction) RelayReason {
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if t.Type == transaction.MinerType {
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return RelayInvalid
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}
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if s.chain.HasTransaction(t.Hash()) {
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return RelayAlreadyExists
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}
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if err := s.chain.Verify(t); err != nil {
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return RelayInvalid
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}
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// TODO: Implement Plugin.CheckPolicy?
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//if (!Plugin.CheckPolicy(transaction))
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// return RelayResultReason.PolicyFail;
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if ok := s.chain.GetMemPool().TryAdd(t.Hash(), core.NewPoolItem(t, s.chain)); !ok {
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return RelayOutOfMemory
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}
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for p := range s.Peers() {
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payload := payload.NewInventory(payload.TXType, []util.Uint256{t.Hash()})
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s.RelayDirectly(p, payload)
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}
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return RelaySucceed
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}
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// RelayDirectly relay directly the inventory to the remote peers.
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// Reference: the method OnRelayDirectly in C#: https://github.com/neo-project/neo/blob/master/neo/Network/P2P/LocalNode.cs#L166
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func (s *Server) RelayDirectly(p Peer, inv *payload.Inventory) {
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if !p.Version().Relay {
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return
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}
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p.WriteMsg(NewMessage(s.Net, CMDInv, inv))
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}
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func init() {
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rand.Seed(time.Now().UTC().UnixNano())
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}
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