Official Go implementation of the Ethereum protocol
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go-ethereum/p2p/server.go

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32 KiB

// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package p2p implements the Ethereum p2p network protocols.
package p2p
import (
"bytes"
"crypto/ecdsa"
"encoding/hex"
"errors"
"fmt"
"net"
"slices"
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/enr"
"github.com/ethereum/go-ethereum/p2p/nat"
"github.com/ethereum/go-ethereum/p2p/netutil"
)
const (
defaultDialTimeout = 15 * time.Second
// This is the fairness knob for the discovery mixer. When looking for peers, we'll
// wait this long for a single source of candidates before moving on and trying other
// sources.
discmixTimeout = 5 * time.Second
// Connectivity defaults.
defaultMaxPendingPeers = 50
defaultDialRatio = 3
// This time limits inbound connection attempts per source IP.
inboundThrottleTime = 30 * time.Second
// Maximum time allowed for reading a complete message.
// This is effectively the amount of time a connection can be idle.
frameReadTimeout = 30 * time.Second
// Maximum amount of time allowed for writing a complete message.
frameWriteTimeout = 20 * time.Second
)
var (
errServerStopped = errors.New("server stopped")
errEncHandshakeError = errors.New("rlpx enc error")
errProtoHandshakeError = errors.New("rlpx proto error")
)
// Config holds Server options.
type Config struct {
// This field must be set to a valid secp256k1 private key.
PrivateKey *ecdsa.PrivateKey `toml:"-"`
// MaxPeers is the maximum number of peers that can be
// connected. It must be greater than zero.
MaxPeers int
// MaxPendingPeers is the maximum number of peers that can be pending in the
// handshake phase, counted separately for inbound and outbound connections.
// Zero defaults to preset values.
MaxPendingPeers int `toml:",omitempty"`
// DialRatio controls the ratio of inbound to dialed connections.
// Example: a DialRatio of 2 allows 1/2 of connections to be dialed.
// Setting DialRatio to zero defaults it to 3.
DialRatio int `toml:",omitempty"`
// NoDiscovery can be used to disable the peer discovery mechanism.
// Disabling is useful for protocol debugging (manual topology).
NoDiscovery bool
// DiscoveryV4 specifies whether V4 discovery should be started.
DiscoveryV4 bool `toml:",omitempty"`
// DiscoveryV5 specifies whether the new topic-discovery based V5 discovery
// protocol should be started or not.
DiscoveryV5 bool `toml:",omitempty"`
// Name sets the node name of this server.
Name string `toml:"-"`
// BootstrapNodes are used to establish connectivity
// with the rest of the network.
BootstrapNodes []*enode.Node
// BootstrapNodesV5 are used to establish connectivity
// with the rest of the network using the V5 discovery
// protocol.
BootstrapNodesV5 []*enode.Node `toml:",omitempty"`
// Static nodes are used as pre-configured connections which are always
// maintained and re-connected on disconnects.
StaticNodes []*enode.Node
// Trusted nodes are used as pre-configured connections which are always
// allowed to connect, even above the peer limit.
TrustedNodes []*enode.Node
// Connectivity can be restricted to certain IP networks.
// If this option is set to a non-nil value, only hosts which match one of the
// IP networks contained in the list are considered.
NetRestrict *netutil.Netlist `toml:",omitempty"`
// NodeDatabase is the path to the database containing the previously seen
// live nodes in the network.
NodeDatabase string `toml:",omitempty"`
// Protocols should contain the protocols supported
// by the server. Matching protocols are launched for
// each peer.
Protocols []Protocol `toml:"-" json:"-"`
// If ListenAddr is set to a non-nil address, the server
// will listen for incoming connections.
//
// If the port is zero, the operating system will pick a port. The
// ListenAddr field will be updated with the actual address when
// the server is started.
ListenAddr string
// If DiscAddr is set to a non-nil value, the server will use ListenAddr
// for TCP and DiscAddr for the UDP discovery protocol.
DiscAddr string
// If set to a non-nil value, the given NAT port mapper
// is used to make the listening port available to the
// Internet.
NAT nat.Interface `toml:",omitempty"`
// If Dialer is set to a non-nil value, the given Dialer
// is used to dial outbound peer connections.
Dialer NodeDialer `toml:"-"`
// If NoDial is true, the server will not dial any peers.
NoDial bool `toml:",omitempty"`
// If EnableMsgEvents is set then the server will emit PeerEvents
// whenever a message is sent to or received from a peer
EnableMsgEvents bool
// Logger is a custom logger to use with the p2p.Server.
Logger log.Logger `toml:",omitempty"`
clock mclock.Clock
}
// Server manages all peer connections.
type Server struct {
// Config fields may not be modified while the server is running.
Config
// Hooks for testing. These are useful because we can inhibit
// the whole protocol stack.
newTransport func(net.Conn, *ecdsa.PublicKey) transport
newPeerHook func(*Peer)
listenFunc func(network, addr string) (net.Listener, error)
lock sync.Mutex // protects running
running bool
listener net.Listener
ourHandshake *protoHandshake
loopWG sync.WaitGroup // loop, listenLoop
peerFeed event.Feed
log log.Logger
nodedb *enode.DB
localnode *enode.LocalNode
discv4 *discover.UDPv4
discv5 *discover.UDPv5
discmix *enode.FairMix
dialsched *dialScheduler
// This is read by the NAT port mapping loop.
portMappingRegister chan *portMapping
// Channels into the run loop.
quit chan struct{}
addtrusted chan *enode.Node
removetrusted chan *enode.Node
peerOp chan peerOpFunc
peerOpDone chan struct{}
delpeer chan peerDrop
checkpointPostHandshake chan *conn
checkpointAddPeer chan *conn
// State of run loop and listenLoop.
inboundHistory expHeap
}
type peerOpFunc func(map[enode.ID]*Peer)
type peerDrop struct {
*Peer
err error
requested bool // true if signaled by the peer
}
type connFlag int32
const (
dynDialedConn connFlag = 1 << iota
staticDialedConn
inboundConn
trustedConn
)
// conn wraps a network connection with information gathered
// during the two handshakes.
type conn struct {
fd net.Conn
transport
node *enode.Node
flags connFlag
cont chan error // The run loop uses cont to signal errors to SetupConn.
caps []Cap // valid after the protocol handshake
name string // valid after the protocol handshake
}
type transport interface {
// The two handshakes.
doEncHandshake(prv *ecdsa.PrivateKey) (*ecdsa.PublicKey, error)
doProtoHandshake(our *protoHandshake) (*protoHandshake, error)
// The MsgReadWriter can only be used after the encryption
// handshake has completed. The code uses conn.id to track this
// by setting it to a non-nil value after the encryption handshake.
MsgReadWriter
// transports must provide Close because we use MsgPipe in some of
// the tests. Closing the actual network connection doesn't do
// anything in those tests because MsgPipe doesn't use it.
close(err error)
}
func (c *conn) String() string {
s := c.flags.String()
if (c.node.ID() != enode.ID{}) {
s += " " + c.node.ID().String()
}
s += " " + c.fd.RemoteAddr().String()
return s
}
func (f connFlag) String() string {
s := ""
if f&trustedConn != 0 {
s += "-trusted"
}
if f&dynDialedConn != 0 {
s += "-dyndial"
}
if f&staticDialedConn != 0 {
s += "-staticdial"
}
if f&inboundConn != 0 {
s += "-inbound"
}
if s != "" {
s = s[1:]
}
return s
}
func (c *conn) is(f connFlag) bool {
flags := connFlag(atomic.LoadInt32((*int32)(&c.flags)))
return flags&f != 0
}
func (c *conn) set(f connFlag, val bool) {
for {
oldFlags := connFlag(atomic.LoadInt32((*int32)(&c.flags)))
flags := oldFlags
if val {
flags |= f
} else {
flags &= ^f
}
if atomic.CompareAndSwapInt32((*int32)(&c.flags), int32(oldFlags), int32(flags)) {
return
}
}
}
// LocalNode returns the local node record.
func (srv *Server) LocalNode() *enode.LocalNode {
return srv.localnode
}
// Peers returns all connected peers.
func (srv *Server) Peers() []*Peer {
var ps []*Peer
srv.doPeerOp(func(peers map[enode.ID]*Peer) {
for _, p := range peers {
ps = append(ps, p)
}
})
return ps
}
// PeerCount returns the number of connected peers.
func (srv *Server) PeerCount() int {
var count int
srv.doPeerOp(func(ps map[enode.ID]*Peer) {
count = len(ps)
})
return count
}
// AddPeer adds the given node to the static node set. When there is room in the peer set,
// the server will connect to the node. If the connection fails for any reason, the server
// will attempt to reconnect the peer.
func (srv *Server) AddPeer(node *enode.Node) {
srv.dialsched.addStatic(node)
}
// RemovePeer removes a node from the static node set. It also disconnects from the given
// node if it is currently connected as a peer.
//
// This method blocks until all protocols have exited and the peer is removed. Do not use
// RemovePeer in protocol implementations, call Disconnect on the Peer instead.
func (srv *Server) RemovePeer(node *enode.Node) {
var (
ch chan *PeerEvent
sub event.Subscription
)
// Disconnect the peer on the main loop.
srv.doPeerOp(func(peers map[enode.ID]*Peer) {
srv.dialsched.removeStatic(node)
if peer := peers[node.ID()]; peer != nil {
ch = make(chan *PeerEvent, 1)
sub = srv.peerFeed.Subscribe(ch)
peer.Disconnect(DiscRequested)
}
})
// Wait for the peer connection to end.
if ch != nil {
defer sub.Unsubscribe()
for ev := range ch {
if ev.Peer == node.ID() && ev.Type == PeerEventTypeDrop {
return
}
}
}
}
// AddTrustedPeer adds the given node to a reserved trusted list which allows the
// node to always connect, even if the slot are full.
func (srv *Server) AddTrustedPeer(node *enode.Node) {
select {
case srv.addtrusted <- node:
case <-srv.quit:
}
}
// RemoveTrustedPeer removes the given node from the trusted peer set.
func (srv *Server) RemoveTrustedPeer(node *enode.Node) {
select {
case srv.removetrusted <- node:
case <-srv.quit:
}
}
// SubscribeEvents subscribes the given channel to peer events
func (srv *Server) SubscribeEvents(ch chan *PeerEvent) event.Subscription {
return srv.peerFeed.Subscribe(ch)
}
// Self returns the local node's endpoint information.
func (srv *Server) Self() *enode.Node {
srv.lock.Lock()
ln := srv.localnode
srv.lock.Unlock()
if ln == nil {
return enode.NewV4(&srv.PrivateKey.PublicKey, net.ParseIP("0.0.0.0"), 0, 0)
}
return ln.Node()
}
// DiscoveryV4 returns the discovery v4 instance, if configured.
func (srv *Server) DiscoveryV4() *discover.UDPv4 {
return srv.discv4
}
// DiscoveryV5 returns the discovery v5 instance, if configured.
func (srv *Server) DiscoveryV5() *discover.UDPv5 {
return srv.discv5
}
// Stop terminates the server and all active peer connections.
// It blocks until all active connections have been closed.
func (srv *Server) Stop() {
srv.lock.Lock()
if !srv.running {
srv.lock.Unlock()
return
}
srv.running = false
if srv.listener != nil {
// this unblocks listener Accept
srv.listener.Close()
}
close(srv.quit)
srv.lock.Unlock()
srv.loopWG.Wait()
}
// sharedUDPConn implements a shared connection. Write sends messages to the underlying connection while read returns
// messages that were found unprocessable and sent to the unhandled channel by the primary listener.
type sharedUDPConn struct {
*net.UDPConn
unhandled chan discover.ReadPacket
}
// ReadFromUDP implements discover.UDPConn
func (s *sharedUDPConn) ReadFromUDP(b []byte) (n int, addr *net.UDPAddr, err error) {
packet, ok := <-s.unhandled
if !ok {
return 0, nil, errors.New("connection was closed")
}
l := len(packet.Data)
if l > len(b) {
l = len(b)
}
copy(b[:l], packet.Data[:l])
return l, packet.Addr, nil
}
// Close implements discover.UDPConn
func (s *sharedUDPConn) Close() error {
return nil
}
// Start starts running the server.
// Servers can not be re-used after stopping.
func (srv *Server) Start() (err error) {
srv.lock.Lock()
defer srv.lock.Unlock()
if srv.running {
return errors.New("server already running")
}
srv.running = true
srv.log = srv.Logger
if srv.log == nil {
srv.log = log.Root()
}
if srv.clock == nil {
srv.clock = mclock.System{}
}
if srv.NoDial && srv.ListenAddr == "" {
srv.log.Warn("P2P server will be useless, neither dialing nor listening")
}
// static fields
if srv.PrivateKey == nil {
return errors.New("Server.PrivateKey must be set to a non-nil key")
}
if srv.newTransport == nil {
srv.newTransport = newRLPX
}
if srv.listenFunc == nil {
srv.listenFunc = net.Listen
}
srv.quit = make(chan struct{})
srv.delpeer = make(chan peerDrop)
srv.checkpointPostHandshake = make(chan *conn)
srv.checkpointAddPeer = make(chan *conn)
srv.addtrusted = make(chan *enode.Node)
srv.removetrusted = make(chan *enode.Node)
srv.peerOp = make(chan peerOpFunc)
srv.peerOpDone = make(chan struct{})
if err := srv.setupLocalNode(); err != nil {
return err
}
srv.setupPortMapping()
if srv.ListenAddr != "" {
if err := srv.setupListening(); err != nil {
return err
}
}
if err := srv.setupDiscovery(); err != nil {
return err
}
srv.setupDialScheduler()
srv.loopWG.Add(1)
go srv.run()
return nil
}
func (srv *Server) setupLocalNode() error {
// Create the devp2p handshake.
pubkey := crypto.FromECDSAPub(&srv.PrivateKey.PublicKey)
srv.ourHandshake = &protoHandshake{Version: baseProtocolVersion, Name: srv.Name, ID: pubkey[1:]}
for _, p := range srv.Protocols {
srv.ourHandshake.Caps = append(srv.ourHandshake.Caps, p.cap())
}
slices.SortFunc(srv.ourHandshake.Caps, Cap.Cmp)
// Create the local node.
db, err := enode.OpenDB(srv.NodeDatabase)
if err != nil {
return err
}
srv.nodedb = db
srv.localnode = enode.NewLocalNode(db, srv.PrivateKey)
srv.localnode.SetFallbackIP(net.IP{127, 0, 0, 1})
// TODO: check conflicts
for _, p := range srv.Protocols {
for _, e := range p.Attributes {
srv.localnode.Set(e)
}
}
return nil
}
func (srv *Server) setupDiscovery() error {
srv.discmix = enode.NewFairMix(discmixTimeout)
// Don't listen on UDP endpoint if DHT is disabled.
if srv.NoDiscovery {
return nil
}
conn, err := srv.setupUDPListening()
if err != nil {
return err
}
var (
sconn discover.UDPConn = conn
unhandled chan discover.ReadPacket
)
// If both versions of discovery are running, setup a shared
// connection, so v5 can read unhandled messages from v4.
if srv.Config.DiscoveryV4 && srv.Config.DiscoveryV5 {
unhandled = make(chan discover.ReadPacket, 100)
sconn = &sharedUDPConn{conn, unhandled}
}
// Start discovery services.
if srv.Config.DiscoveryV4 {
cfg := discover.Config{
PrivateKey: srv.PrivateKey,
NetRestrict: srv.NetRestrict,
Bootnodes: srv.BootstrapNodes,
Unhandled: unhandled,
Log: srv.log,
}
ntab, err := discover.ListenV4(conn, srv.localnode, cfg)
if err != nil {
return err
}
srv.discv4 = ntab
srv.discmix.AddSource(ntab.RandomNodes())
}
if srv.Config.DiscoveryV5 {
cfg := discover.Config{
PrivateKey: srv.PrivateKey,
NetRestrict: srv.NetRestrict,
Bootnodes: srv.BootstrapNodesV5,
Log: srv.log,
}
srv.discv5, err = discover.ListenV5(sconn, srv.localnode, cfg)
if err != nil {
return err
}
}
// Add protocol-specific discovery sources.
added := make(map[string]bool)
for _, proto := range srv.Protocols {
if proto.DialCandidates != nil && !added[proto.Name] {
srv.discmix.AddSource(proto.DialCandidates)
added[proto.Name] = true
}
}
return nil
}
func (srv *Server) setupDialScheduler() {
config := dialConfig{
self: srv.localnode.ID(),
maxDialPeers: srv.maxDialedConns(),
maxActiveDials: srv.MaxPendingPeers,
log: srv.Logger,
netRestrict: srv.NetRestrict,
dialer: srv.Dialer,
clock: srv.clock,
}
if srv.discv4 != nil {
config.resolver = srv.discv4
}
if config.dialer == nil {
config.dialer = tcpDialer{&net.Dialer{Timeout: defaultDialTimeout}}
}
srv.dialsched = newDialScheduler(config, srv.discmix, srv.SetupConn)
for _, n := range srv.StaticNodes {
srv.dialsched.addStatic(n)
}
}
func (srv *Server) maxInboundConns() int {
return srv.MaxPeers - srv.maxDialedConns()
}
func (srv *Server) maxDialedConns() (limit int) {
if srv.NoDial || srv.MaxPeers == 0 {
return 0
}
if srv.DialRatio == 0 {
limit = srv.MaxPeers / defaultDialRatio
} else {
limit = srv.MaxPeers / srv.DialRatio
}
if limit == 0 {
limit = 1
}
return limit
}
func (srv *Server) setupListening() error {
// Launch the listener.
listener, err := srv.listenFunc("tcp", srv.ListenAddr)
if err != nil {
return err
}
srv.listener = listener
srv.ListenAddr = listener.Addr().String()
// Update the local node record and map the TCP listening port if NAT is configured.
tcp, isTCP := listener.Addr().(*net.TCPAddr)
if isTCP {
srv.localnode.Set(enr.TCP(tcp.Port))
if !tcp.IP.IsLoopback() && !tcp.IP.IsPrivate() {
srv.portMappingRegister <- &portMapping{
protocol: "TCP",
name: "ethereum p2p",
port: tcp.Port,
}
}
}
srv.loopWG.Add(1)
go srv.listenLoop()
return nil
}
func (srv *Server) setupUDPListening() (*net.UDPConn, error) {
listenAddr := srv.ListenAddr
// Use an alternate listening address for UDP if
// a custom discovery address is configured.
if srv.DiscAddr != "" {
listenAddr = srv.DiscAddr
}
addr, err := net.ResolveUDPAddr("udp", listenAddr)
if err != nil {
return nil, err
}
conn, err := net.ListenUDP("udp", addr)
if err != nil {
return nil, err
}
laddr := conn.LocalAddr().(*net.UDPAddr)
srv.localnode.SetFallbackUDP(laddr.Port)
srv.log.Debug("UDP listener up", "addr", laddr)
if !laddr.IP.IsLoopback() && !laddr.IP.IsPrivate() {
srv.portMappingRegister <- &portMapping{
protocol: "UDP",
name: "ethereum peer discovery",
port: laddr.Port,
}
}
return conn, nil
}
// doPeerOp runs fn on the main loop.
func (srv *Server) doPeerOp(fn peerOpFunc) {
select {
case srv.peerOp <- fn:
<-srv.peerOpDone
case <-srv.quit:
}
}
// run is the main loop of the server.
func (srv *Server) run() {
srv.log.Info("Started P2P networking", "self", srv.localnode.Node().URLv4())
defer srv.loopWG.Done()
defer srv.nodedb.Close()
defer srv.discmix.Close()
defer srv.dialsched.stop()
var (
peers = make(map[enode.ID]*Peer)
inboundCount = 0
trusted = make(map[enode.ID]bool, len(srv.TrustedNodes))
)
// Put trusted nodes into a map to speed up checks.
// Trusted peers are loaded on startup or added via AddTrustedPeer RPC.
for _, n := range srv.TrustedNodes {
trusted[n.ID()] = true
}
running:
for {
select {
case <-srv.quit:
// The server was stopped. Run the cleanup logic.
break running
case n := <-srv.addtrusted:
// This channel is used by AddTrustedPeer to add a node
// to the trusted node set.
srv.log.Trace("Adding trusted node", "node", n)
trusted[n.ID()] = true
if p, ok := peers[n.ID()]; ok {
p.rw.set(trustedConn, true)
}
case n := <-srv.removetrusted:
// This channel is used by RemoveTrustedPeer to remove a node
// from the trusted node set.
srv.log.Trace("Removing trusted node", "node", n)
delete(trusted, n.ID())
if p, ok := peers[n.ID()]; ok {
p.rw.set(trustedConn, false)
}
case op := <-srv.peerOp:
// This channel is used by Peers and PeerCount.
op(peers)
srv.peerOpDone <- struct{}{}
case c := <-srv.checkpointPostHandshake:
// A connection has passed the encryption handshake so
// the remote identity is known (but hasn't been verified yet).
if trusted[c.node.ID()] {
// Ensure that the trusted flag is set before checking against MaxPeers.
c.flags |= trustedConn
}
// TODO: track in-progress inbound node IDs (pre-Peer) to avoid dialing them.
c.cont <- srv.postHandshakeChecks(peers, inboundCount, c)
case c := <-srv.checkpointAddPeer:
// At this point the connection is past the protocol handshake.
// Its capabilities are known and the remote identity is verified.
err := srv.addPeerChecks(peers, inboundCount, c)
if err == nil {
// The handshakes are done and it passed all checks.
p := srv.launchPeer(c)
peers[c.node.ID()] = p
srv.log.Debug("Adding p2p peer", "peercount", len(peers), "id", p.ID(), "conn", c.flags, "addr", p.RemoteAddr(), "name", p.Name())
srv.dialsched.peerAdded(c)
if p.Inbound() {
inboundCount++
serveSuccessMeter.Mark(1)
activeInboundPeerGauge.Inc(1)
} else {
dialSuccessMeter.Mark(1)
activeOutboundPeerGauge.Inc(1)
}
activePeerGauge.Inc(1)
}
c.cont <- err
case pd := <-srv.delpeer:
// A peer disconnected.
d := common.PrettyDuration(mclock.Now() - pd.created)
delete(peers, pd.ID())
srv.log.Debug("Removing p2p peer", "peercount", len(peers), "id", pd.ID(), "duration", d, "req", pd.requested, "err", pd.err)
srv.dialsched.peerRemoved(pd.rw)
if pd.Inbound() {
inboundCount--
activeInboundPeerGauge.Dec(1)
} else {
activeOutboundPeerGauge.Dec(1)
}
activePeerGauge.Dec(1)
}
}
srv.log.Trace("P2P networking is spinning down")
// Terminate discovery. If there is a running lookup it will terminate soon.
if srv.discv4 != nil {
srv.discv4.Close()
}
if srv.discv5 != nil {
srv.discv5.Close()
}
// Disconnect all peers.
for _, p := range peers {
p.Disconnect(DiscQuitting)
}
// Wait for peers to shut down. Pending connections and tasks are
// not handled here and will terminate soon-ish because srv.quit
// is closed.
for len(peers) > 0 {
p := <-srv.delpeer
p.log.Trace("<-delpeer (spindown)")
delete(peers, p.ID())
}
}
func (srv *Server) postHandshakeChecks(peers map[enode.ID]*Peer, inboundCount int, c *conn) error {
switch {
case !c.is(trustedConn) && len(peers) >= srv.MaxPeers:
return DiscTooManyPeers
case !c.is(trustedConn) && c.is(inboundConn) && inboundCount >= srv.maxInboundConns():
return DiscTooManyPeers
case peers[c.node.ID()] != nil:
return DiscAlreadyConnected
case c.node.ID() == srv.localnode.ID():
return DiscSelf
default:
return nil
}
}
func (srv *Server) addPeerChecks(peers map[enode.ID]*Peer, inboundCount int, c *conn) error {
// Drop connections with no matching protocols.
if len(srv.Protocols) > 0 && countMatchingProtocols(srv.Protocols, c.caps) == 0 {
return DiscUselessPeer
}
// Repeat the post-handshake checks because the
// peer set might have changed since those checks were performed.
return srv.postHandshakeChecks(peers, inboundCount, c)
}
// listenLoop runs in its own goroutine and accepts
// inbound connections.
func (srv *Server) listenLoop() {
srv.log.Debug("TCP listener up", "addr", srv.listener.Addr())
// The slots channel limits accepts of new connections.
tokens := defaultMaxPendingPeers
if srv.MaxPendingPeers > 0 {
tokens = srv.MaxPendingPeers
}
slots := make(chan struct{}, tokens)
for i := 0; i < tokens; i++ {
slots <- struct{}{}
}
// Wait for slots to be returned on exit. This ensures all connection goroutines
// are down before listenLoop returns.
defer srv.loopWG.Done()
defer func() {
for i := 0; i < cap(slots); i++ {
<-slots
}
}()
for {
// Wait for a free slot before accepting.
<-slots
var (
fd net.Conn
err error
lastLog time.Time
)
for {
fd, err = srv.listener.Accept()
if netutil.IsTemporaryError(err) {
if time.Since(lastLog) > 1*time.Second {
srv.log.Debug("Temporary read error", "err", err)
lastLog = time.Now()
}
time.Sleep(time.Millisecond * 200)
continue
} else if err != nil {
srv.log.Debug("Read error", "err", err)
slots <- struct{}{}
return
}
break
}
remoteIP := netutil.AddrIP(fd.RemoteAddr())
if err := srv.checkInboundConn(remoteIP); err != nil {
srv.log.Debug("Rejected inbound connection", "addr", fd.RemoteAddr(), "err", err)
fd.Close()
slots <- struct{}{}
continue
}
if remoteIP != nil {
fd = newMeteredConn(fd)
serveMeter.Mark(1)
srv.log.Trace("Accepted connection", "addr", fd.RemoteAddr())
}
go func() {
srv.SetupConn(fd, inboundConn, nil)
slots <- struct{}{}
}()
}
}
func (srv *Server) checkInboundConn(remoteIP net.IP) error {
if remoteIP == nil {
return nil
}
// Reject connections that do not match NetRestrict.
if srv.NetRestrict != nil && !srv.NetRestrict.Contains(remoteIP) {
return errors.New("not in netrestrict list")
}
// Reject Internet peers that try too often.
now := srv.clock.Now()
srv.inboundHistory.expire(now, nil)
if !netutil.IsLAN(remoteIP) && srv.inboundHistory.contains(remoteIP.String()) {
return errors.New("too many attempts")
}
srv.inboundHistory.add(remoteIP.String(), now.Add(inboundThrottleTime))
return nil
}
// SetupConn runs the handshakes and attempts to add the connection
// as a peer. It returns when the connection has been added as a peer
// or the handshakes have failed.
func (srv *Server) SetupConn(fd net.Conn, flags connFlag, dialDest *enode.Node) error {
c := &conn{fd: fd, flags: flags, cont: make(chan error)}
if dialDest == nil {
c.transport = srv.newTransport(fd, nil)
} else {
c.transport = srv.newTransport(fd, dialDest.Pubkey())
}
err := srv.setupConn(c, dialDest)
if err != nil {
if !c.is(inboundConn) {
markDialError(err)
}
c.close(err)
}
return err
}
func (srv *Server) setupConn(c *conn, dialDest *enode.Node) error {
// Prevent leftover pending conns from entering the handshake.
srv.lock.Lock()
running := srv.running
srv.lock.Unlock()
if !running {
return errServerStopped
}
// If dialing, figure out the remote public key.
if dialDest != nil {
dialPubkey := new(ecdsa.PublicKey)
if err := dialDest.Load((*enode.Secp256k1)(dialPubkey)); err != nil {
err = fmt.Errorf("%w: dial destination doesn't have a secp256k1 public key", errEncHandshakeError)
srv.log.Trace("Setting up connection failed", "addr", c.fd.RemoteAddr(), "conn", c.flags, "err", err)
return err
}
}
// Run the RLPx handshake.
remotePubkey, err := c.doEncHandshake(srv.PrivateKey)
if err != nil {
srv.log.Trace("Failed RLPx handshake", "addr", c.fd.RemoteAddr(), "conn", c.flags, "err", err)
return fmt.Errorf("%w: %v", errEncHandshakeError, err)
}
if dialDest != nil {
c.node = dialDest
} else {
c.node = nodeFromConn(remotePubkey, c.fd)
}
clog := srv.log.New("id", c.node.ID(), "addr", c.fd.RemoteAddr(), "conn", c.flags)
err = srv.checkpoint(c, srv.checkpointPostHandshake)
if err != nil {
clog.Trace("Rejected peer", "err", err)
return err
}
// Run the capability negotiation handshake.
phs, err := c.doProtoHandshake(srv.ourHandshake)
if err != nil {
clog.Trace("Failed p2p handshake", "err", err)
return fmt.Errorf("%w: %v", errProtoHandshakeError, err)
}
if id := c.node.ID(); !bytes.Equal(crypto.Keccak256(phs.ID), id[:]) {
clog.Trace("Wrong devp2p handshake identity", "phsid", hex.EncodeToString(phs.ID))
return DiscUnexpectedIdentity
}
c.caps, c.name = phs.Caps, phs.Name
err = srv.checkpoint(c, srv.checkpointAddPeer)
if err != nil {
clog.Trace("Rejected peer", "err", err)
return err
}
return nil
}
func nodeFromConn(pubkey *ecdsa.PublicKey, conn net.Conn) *enode.Node {
var ip net.IP
var port int
if tcp, ok := conn.RemoteAddr().(*net.TCPAddr); ok {
ip = tcp.IP
port = tcp.Port
}
return enode.NewV4(pubkey, ip, port, port)
}
// checkpoint sends the conn to run, which performs the
// post-handshake checks for the stage (posthandshake, addpeer).
func (srv *Server) checkpoint(c *conn, stage chan<- *conn) error {
select {
case stage <- c:
case <-srv.quit:
return errServerStopped
}
return <-c.cont
}
func (srv *Server) launchPeer(c *conn) *Peer {
p := newPeer(srv.log, c, srv.Protocols)
if srv.EnableMsgEvents {
// If message events are enabled, pass the peerFeed
// to the peer.
p.events = &srv.peerFeed
}
go srv.runPeer(p)
return p
}
// runPeer runs in its own goroutine for each peer.
func (srv *Server) runPeer(p *Peer) {
if srv.newPeerHook != nil {
srv.newPeerHook(p)
}
srv.peerFeed.Send(&PeerEvent{
Type: PeerEventTypeAdd,
Peer: p.ID(),
RemoteAddress: p.RemoteAddr().String(),
LocalAddress: p.LocalAddr().String(),
})
// Run the per-peer main loop.
remoteRequested, err := p.run()
// Announce disconnect on the main loop to update the peer set.
// The main loop waits for existing peers to be sent on srv.delpeer
// before returning, so this send should not select on srv.quit.
srv.delpeer <- peerDrop{p, err, remoteRequested}
// Broadcast peer drop to external subscribers. This needs to be
// after the send to delpeer so subscribers have a consistent view of
// the peer set (i.e. Server.Peers() doesn't include the peer when the
// event is received).
srv.peerFeed.Send(&PeerEvent{
Type: PeerEventTypeDrop,
Peer: p.ID(),
Error: err.Error(),
RemoteAddress: p.RemoteAddr().String(),
LocalAddress: p.LocalAddr().String(),
})
}
// NodeInfo represents a short summary of the information known about the host.
type NodeInfo struct {
ID string `json:"id"` // Unique node identifier (also the encryption key)
Name string `json:"name"` // Name of the node, including client type, version, OS, custom data
Enode string `json:"enode"` // Enode URL for adding this peer from remote peers
ENR string `json:"enr"` // Ethereum Node Record
IP string `json:"ip"` // IP address of the node
Ports struct {
Discovery int `json:"discovery"` // UDP listening port for discovery protocol
Listener int `json:"listener"` // TCP listening port for RLPx
} `json:"ports"`
ListenAddr string `json:"listenAddr"`
Protocols map[string]interface{} `json:"protocols"`
}
// NodeInfo gathers and returns a collection of metadata known about the host.
func (srv *Server) NodeInfo() *NodeInfo {
// Gather and assemble the generic node infos
node := srv.Self()
info := &NodeInfo{
Name: srv.Name,
Enode: node.URLv4(),
ID: node.ID().String(),
IP: node.IP().String(),
ListenAddr: srv.ListenAddr,
Protocols: make(map[string]interface{}),
}
info.Ports.Discovery = node.UDP()
info.Ports.Listener = node.TCP()
info.ENR = node.String()
// Gather all the running protocol infos (only once per protocol type)
for _, proto := range srv.Protocols {
if _, ok := info.Protocols[proto.Name]; !ok {
nodeInfo := interface{}("unknown")
if query := proto.NodeInfo; query != nil {
nodeInfo = proto.NodeInfo()
}
info.Protocols[proto.Name] = nodeInfo
}
}
return info
}
// PeersInfo returns an array of metadata objects describing connected peers.
func (srv *Server) PeersInfo() []*PeerInfo {
// Gather all the generic and sub-protocol specific infos
infos := make([]*PeerInfo, 0, srv.PeerCount())
for _, peer := range srv.Peers() {
if peer != nil {
infos = append(infos, peer.Info())
}
}
// Sort the result array alphabetically by node identifier
for i := 0; i < len(infos); i++ {
for j := i + 1; j < len(infos); j++ {
if infos[i].ID > infos[j].ID {
infos[i], infos[j] = infos[j], infos[i]
}
}
}
return infos
}