neoneo-go/pkg/network/server.go

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package network
import (
"errors"
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"fmt"
"math/rand"
"net"
"sync"
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"time"
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"github.com/CityOfZion/neo-go/pkg/core"
"github.com/CityOfZion/neo-go/pkg/core/transaction"
"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 (
// peer numbers are arbitrary at the moment
minPeers = 5
maxPeers = 20
maxBlockBatch = 200
maxAddrsToSend = 200
minPoolCount = 30
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)
var (
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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addrReq chan *Message
register chan Peer
unregister chan peerDrop
quit chan struct{}
}
peerDrop struct {
peer Peer
reason error
}
)
// NewServer returns a new Server, initialized with the given configuration.
func NewServer(config ServerConfig, chain core.Blockchainer) *Server {
s := &Server{
ServerConfig: config,
chain: chain,
id: rand.Uint32(),
quit: make(chan struct{}),
addrReq: make(chan *Message, minPeers),
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.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")
s.discovery.BackFill(s.Seeds...)
go s.transport.Accept()
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 []string{}
}
// BadPeers returns a list of peers the are flagged as "bad" peers.
func (s *Server) BadPeers() []string {
return []string{}
}
func (s *Server) run() {
for {
c := s.PeerCount()
if c < minPeers {
s.discovery.RequestRemote(maxPeers - c)
}
if s.discovery.PoolCount() < minPoolCount {
select {
case s.addrReq <- NewMessage(s.Net, CMDGetAddr, payload.NewNullPayload()):
// sent request
default:
// we have one in the queue already that is
// gonna be served by some worker when it's ready
}
}
select {
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.
if err := s.sendVersion(p); err != nil {
log.WithFields(log.Fields{
"addr": p.NetAddr(),
}).Error(err)
}
s.peers[p] = true
log.WithFields(log.Fields{
"addr": p.NetAddr(),
}).Info("new peer connected")
case drop := <-s.unregister:
if s.peers[drop.peer] {
delete(s.peers, drop.peer)
log.WithFields(log.Fields{
"addr": drop.peer.NetAddr(),
"reason": drop.reason,
"peerCount": s.PeerCount(),
}).Warn("peer disconnected")
addr := drop.peer.NetAddr().String()
s.discovery.UnregisterConnectedAddr(addr)
s.discovery.BackFill(addr)
}
// else the peer is already gone, which can happen
// because we have two goroutines sending signals here
}
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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{
"addr": p.NetAddr(),
"userAgent": string(p.Version().UserAgent),
"startHeight": p.Version().StartHeight,
"id": p.Version().Nonce,
}).Info("started protocol")
s.discovery.RegisterGoodAddr(p.NetAddr().String())
err := s.requestHeaders(p)
if err != nil {
p.Disconnect(err)
return
}
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timer := time.NewTimer(s.ProtoTickInterval)
for {
select {
case err = <-p.Done():
// time to stop
case m := <-s.addrReq:
err = p.WriteMsg(m)
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() {
err = s.requestBlocks(p)
}
if err == nil {
timer.Reset(s.ProtoTickInterval)
}
}
if err != nil {
s.unregister <- peerDrop{p, err}
timer.Stop()
p.Disconnect(err)
return
}
}
}
// When a peer connects to the server, we will send our version immediately.
func (s *Server) sendVersion(p Peer) error {
payload := payload.NewVersion(
s.id,
s.ListenTCP,
s.UserAgent,
s.chain.BlockHeight(),
s.Relay,
)
return p.SendVersion(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 {
err := p.HandleVersion(version)
if err != nil {
return err
}
if s.id == version.Nonce {
return errIdenticalID
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}
if p.NetAddr().Port != int(version.Port) {
return fmt.Errorf("port mismatch: connected to %d and peer sends %d", p.NetAddr().Port, version.Port)
}
return p.SendVersionAck(NewMessage(s.Net, CMDVerack, 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)
return p.WriteMsg(NewMessage(s.Net, CMDGetData, payload))
}
// handleAddrCmd will process received addresses.
func (s *Server) handleAddrCmd(p Peer, addrs *payload.AddressList) error {
for _, a := range addrs.Addrs {
s.discovery.BackFill(a.IPPortString())
}
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) > maxAddrsToSend {
addrs = addrs[:maxAddrsToSend]
}
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)
alist.Addrs[i] = payload.NewAddressAndTime(netaddr, ts)
}
return p.WriteMsg(NewMessage(s.Net, CMDAddr, alist))
}
// 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) error {
start := []util.Uint256{s.chain.CurrentHeaderHash()}
payload := payload.NewGetBlocks(start, util.Uint256{})
return p.WriteMsg(NewMessage(s.Net, CMDGetHeaders, payload))
}
// 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) error {
var (
hashes []util.Uint256
hashStart = s.chain.BlockHeight() + 1
headerHeight = s.chain.HeaderHeight()
)
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)
return p.WriteMsg(NewMessage(s.Net, CMDGetData, payload))
} else if s.chain.HeaderHeight() < p.Version().StartHeight {
return s.requestHeaders(p)
}
return nil
}
// handleMessage will process the given message.
func (s *Server) handleMessage(peer Peer, msg *Message) error {
// Make sure both server and peer are operating on
// the same network.
if msg.Magic != s.Net {
return errInvalidNetwork
}
if peer.Handshaked() {
switch msg.CommandType() {
case CMDAddr:
addrs := msg.Payload.(*payload.AddressList)
return s.handleAddrCmd(peer, addrs)
case CMDGetAddr:
// it has no payload
return s.handleGetAddrCmd(peer)
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 CMDVersion, CMDVerack:
return fmt.Errorf("received '%s' after the handshake", msg.CommandType())
}
} else {
switch msg.CommandType() {
case CMDVersion:
version := msg.Payload.(*payload.Version)
return s.handleVersionCmd(peer, version)
case CMDVerack:
err := peer.HandleVersionAck()
if err != nil {
return err
}
go s.startProtocol(peer)
default:
return fmt.Errorf("received '%s' during handshake", msg.CommandType())
}
}
return nil
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}
// 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) RelayReason {
if t.Type == transaction.MinerType {
return RelayInvalid
}
if s.chain.HasTransaction(t.Hash()) {
return RelayAlreadyExists
}
if err := s.chain.Verify(t); err != nil {
return RelayInvalid
}
// TODO: Implement Plugin.CheckPolicy?
//if (!Plugin.CheckPolicy(transaction))
// return RelayResultReason.PolicyFail;
if ok := s.chain.GetMemPool().TryAdd(t.Hash(), core.NewPoolItem(t, s.chain)); !ok {
return RelayOutOfMemory
}
for p := range s.Peers() {
payload := payload.NewInventory(payload.TXType, []util.Uint256{t.Hash()})
s.RelayDirectly(p, payload)
}
return RelaySucceed
}
// RelayDirectly relay directly the inventory to the remote peers.
// Reference: the method OnRelayDirectly in C#: https://github.com/neo-project/neo/blob/master/neo/Network/P2P/LocalNode.cs#L166
func (s *Server) RelayDirectly(p Peer, inv *payload.Inventory) {
if !p.Version().Relay {
return
}
p.WriteMsg(NewMessage(s.Net, CMDInv, inv))
}
func init() {
rand.Seed(time.Now().UTC().UnixNano())
}