neoneo-go/pkg/network/server.go

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package network
import (
"errors"
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"fmt"
"sync"
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"time"
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"github.com/CityOfZion/neo-go/pkg/core"
"github.com/CityOfZion/neo-go/pkg/network/payload"
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"github.com/CityOfZion/neo-go/pkg/util"
log "github.com/sirupsen/logrus"
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)
const (
minPeers = 5
maxBlockBatch = 200
minPoolCount = 30
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)
var (
errPortMismatch = errors.New("port mismatch")
errIdenticalID = errors.New("identical node id")
errInvalidHandshake = errors.New("invalid handshake")
errInvalidNetwork = errors.New("invalid network")
errServerShutdown = errors.New("server shutdown")
errInvalidInvType = errors.New("invalid inventory type")
)
type (
// 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
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transport Transporter
discovery Discoverer
chain core.Blockchainer
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lock sync.RWMutex
peers map[Peer]bool
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register chan Peer
unregister chan peerDrop
quit chan struct{}
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proto <-chan protoTuple
}
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protoTuple struct {
msg *Message
peer Peer
}
peerDrop struct {
peer Peer
reason error
}
)
// NewServer returns a new Server, initialized with the given configuration.
func NewServer(config ServerConfig, chain *core.Blockchain) *Server {
s := &Server{
ServerConfig: config,
chain: chain,
id: util.RandUint32(1000000, 9999999),
quit: make(chan struct{}),
register: make(chan Peer),
unregister: make(chan peerDrop),
peers: make(map[Peer]bool),
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}
s.transport = NewTCPTransport(s, fmt.Sprintf(":%d", config.ListenTCP))
s.proto = s.transport.Consumer()
s.discovery = NewDefaultDiscovery(
s.DialTimeout,
s.transport,
)
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return s
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}
// ID returns the servers ID.
func (s *Server) ID() uint32 {
return s.id
}
// Start will start the server and its underlying transport.
func (s *Server) Start(errChan chan error) {
log.WithFields(log.Fields{
"blockHeight": s.chain.BlockHeight(),
"headerHeight": s.chain.HeaderHeight(),
}).Info("node started")
go s.transport.Accept()
s.discovery.BackFill(s.Seeds...)
s.run()
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}
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// Shutdown disconnects all peers and stops listening.
func (s *Server) Shutdown() {
log.WithFields(log.Fields{
"peers": s.PeerCount(),
}).Info("shutting down server")
close(s.quit)
}
// 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 the are flagged as "bad" peers.
func (s *Server) BadPeers() []string {
return s.discovery.BadPeers()
}
func (s *Server) run() {
// Ask discovery to connect with remote nodes to fill up
// the server minimum peer slots.
s.discovery.RequestRemote(minPeers - s.PeerCount())
for {
select {
case proto := <-s.proto:
if err := s.processProto(proto); err != nil {
proto.peer.Disconnect(err)
// verack and version implies that the protocol is
// not started and the only way to disconnect them
// from the server is to manually call unregister.
switch proto.msg.CommandType() {
case CMDVerack, CMDVersion:
go func() {
s.unregister <- peerDrop{proto.peer, err}
}()
}
}
case <-s.quit:
s.transport.Close()
for p := range s.peers {
p.Disconnect(errServerShutdown)
}
return
case p := <-s.register:
// When a new peer is connected we send out our version immediately.
s.sendVersion(p)
s.peers[p] = true
log.WithFields(log.Fields{
"endpoint": p.Endpoint(),
}).Info("new peer connected")
case drop := <-s.unregister:
s.discovery.RegisterBadAddr(drop.peer.Endpoint().String())
delete(s.peers, drop.peer)
log.WithFields(log.Fields{
"endpoint": drop.peer.Endpoint(),
"reason": drop.reason,
"peerCount": s.PeerCount(),
}).Warn("peer disconnected")
}
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}
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}
// Peers returns the current list of peers connected to
// the server.
func (s *Server) Peers() map[Peer]bool {
return s.peers
}
// PeerCount returns the number of current connected peers.
func (s *Server) PeerCount() int {
s.lock.RLock()
defer s.lock.RUnlock()
return len(s.peers)
}
// startProtocol starts a long running background loop that interacts
// every ProtoTickInterval with the peer.
func (s *Server) startProtocol(p Peer) {
log.WithFields(log.Fields{
"endpoint": p.Endpoint(),
"userAgent": string(p.Version().UserAgent),
"startHeight": p.Version().StartHeight,
"id": p.Version().Nonce,
}).Info("started protocol")
s.requestHeaders(p)
s.requestPeerInfo(p)
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timer := time.NewTimer(s.ProtoTickInterval)
for {
select {
case err := <-p.Done():
s.unregister <- peerDrop{p, err}
return
case <-timer.C:
// Try to sync in headers and block with the peer if his block height is higher then ours.
if p.Version().StartHeight > s.chain.BlockHeight() {
s.requestBlocks(p)
}
// If the discovery does not have a healthy address pool
// we will ask for a new batch of addresses.
if s.discovery.PoolCount() < minPoolCount {
s.requestPeerInfo(p)
}
timer.Reset(s.ProtoTickInterval)
}
}
}
// When a peer connects to the server, we will send our version immediately.
func (s *Server) sendVersion(p Peer) {
payload := payload.NewVersion(
s.id,
s.ListenTCP,
s.UserAgent,
s.chain.BlockHeight(),
s.Relay,
)
p.Send(NewMessage(s.Net, CMDVersion, payload))
}
// When a peer sends out his version we reply with verack after validating
// the version.
func (s *Server) handleVersionCmd(p Peer, version *payload.Version) error {
if p.Endpoint().Port != version.Port {
return errPortMismatch
}
if s.id == version.Nonce {
return errIdenticalID
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}
p.Send(NewMessage(s.Net, CMDVerack, nil))
return nil
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}
// handleHeadersCmd will process the headers it received from its peer.
// if the headerHeight of the blockchain still smaller then the peer
// the server will request more headers.
// This method could best be called in a separate routine.
func (s *Server) handleHeadersCmd(p Peer, headers *payload.Headers) {
if err := s.chain.AddHeaders(headers.Hdrs...); err != nil {
log.Warnf("failed processing headers: %s", err)
return
}
// The peer will respond with a maximum of 2000 headers in one batch.
// We will ask one more batch here if needed. Eventually we will get synced
// due to the startProtocol routine that will ask headers every protoTick.
if s.chain.HeaderHeight() < p.Version().StartHeight {
s.requestHeaders(p)
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}
}
// handleBlockCmd processes the received block received from its peer.
func (s *Server) handleBlockCmd(p Peer, block *core.Block) error {
if !s.chain.HasBlock(block.Hash()) {
return s.chain.AddBlock(block)
}
return nil
}
// handleInvCmd will process the received inventory.
func (s *Server) handleInvCmd(p Peer, inv *payload.Inventory) error {
if !inv.Type.Valid() || len(inv.Hashes) == 0 {
return errInvalidInvType
}
payload := payload.NewInventory(inv.Type, inv.Hashes)
p.Send(NewMessage(s.Net, CMDGetData, payload))
return nil
}
func (s *Server) handleGetHeadersCmd(p Peer, getHeaders *payload.GetBlocks) error {
log.Info(getHeaders)
return nil
}
// requestHeaders will send a getheaders message to the peer.
// The peer will respond with headers op to a count of 2000.
func (s *Server) requestHeaders(p Peer) {
start := []util.Uint256{s.chain.CurrentHeaderHash()}
payload := payload.NewGetBlocks(start, util.Uint256{})
p.Send(NewMessage(s.Net, CMDGetHeaders, payload))
}
// requestPeerInfo will send a getaddr message to the peer
// which will respond with his known addresses in the network.
func (s *Server) requestPeerInfo(p Peer) {
p.Send(NewMessage(s.Net, CMDGetAddr, nil))
}
// requestBlocks will send a getdata message to the peer
// to sync up in blocks. A maximum of maxBlockBatch will
// send at once.
func (s *Server) requestBlocks(p Peer) {
var (
hashStart = s.chain.BlockHeight() + 1
headerHeight = s.chain.HeaderHeight()
hashes = []util.Uint256{}
)
for hashStart < headerHeight && len(hashes) < maxBlockBatch {
hash := s.chain.GetHeaderHash(int(hashStart))
hashes = append(hashes, hash)
hashStart++
}
if len(hashes) > 0 {
payload := payload.NewInventory(payload.BlockType, hashes)
p.Send(NewMessage(s.Net, CMDGetData, payload))
} else if s.chain.HeaderHeight() < p.Version().StartHeight {
s.requestHeaders(p)
}
}
// process the received protocol message.
func (s *Server) processProto(proto protoTuple) error {
var (
peer = proto.peer
msg = proto.msg
)
// Make sure both server and peer are operating on
// the same network.
if msg.Magic != s.Net {
return errInvalidNetwork
}
switch msg.CommandType() {
case CMDVersion:
version := msg.Payload.(*payload.Version)
return s.handleVersionCmd(peer, version)
case CMDHeaders:
headers := msg.Payload.(*payload.Headers)
go s.handleHeadersCmd(peer, headers)
case CMDInv:
inventory := msg.Payload.(*payload.Inventory)
return s.handleInvCmd(peer, inventory)
case CMDBlock:
block := msg.Payload.(*core.Block)
return s.handleBlockCmd(peer, block)
case CMDGetHeaders:
getHeaders := msg.Payload.(*payload.GetBlocks)
s.handleGetHeadersCmd(peer, getHeaders)
case CMDVerack:
// Make sure this peer has send his version before we start the
// protocol with that peer.
if peer.Version() == nil {
return errInvalidHandshake
}
go s.startProtocol(peer)
case CMDAddr:
addressList := msg.Payload.(*payload.AddressList)
for _, addr := range addressList.Addrs {
s.discovery.BackFill(addr.Endpoint.String())
}
}
return nil
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}