plugeth/p2p/peer.go
Felix Lange 5110f80bba p2p: improve read deadlines
There are now two deadlines, frameReadTimeout and payloadReadTimeout.

The frame timeout is longer and allows for connections that are idle.
The message timeout is still short and ensures that we don't get stuck
in the middle of a message.
2015-02-13 14:44:00 +01:00

398 lines
9.3 KiB
Go

package p2p
import (
"errors"
"fmt"
"io"
"io/ioutil"
"net"
"sort"
"sync"
"time"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/rlp"
)
const (
baseProtocolVersion = 2
baseProtocolLength = uint64(16)
baseProtocolMaxMsgSize = 10 * 1024 * 1024
disconnectGracePeriod = 2 * time.Second
)
const (
// devp2p message codes
handshakeMsg = 0x00
discMsg = 0x01
pingMsg = 0x02
pongMsg = 0x03
getPeersMsg = 0x04
peersMsg = 0x05
)
// handshake is the RLP structure of the protocol handshake.
type handshake struct {
Version uint64
Name string
Caps []Cap
ListenPort uint64
NodeID discover.NodeID
}
// Peer represents a connected remote node.
type Peer struct {
// Peers have all the log methods.
// Use them to display messages related to the peer.
*logger.Logger
infoMu sync.Mutex
name string
caps []Cap
ourID, remoteID *discover.NodeID
ourName string
rw *frameRW
// These fields maintain the running protocols.
protocols []Protocol
runlock sync.RWMutex // protects running
running map[string]*proto
// disables protocol handshake, for testing
noHandshake bool
protoWG sync.WaitGroup
protoErr chan error
closed chan struct{}
disc chan DiscReason
}
// NewPeer returns a peer for testing purposes.
func NewPeer(id discover.NodeID, name string, caps []Cap) *Peer {
conn, _ := net.Pipe()
peer := newPeer(conn, nil, "", nil, &id)
peer.setHandshakeInfo(name, caps)
close(peer.closed) // ensures Disconnect doesn't block
return peer
}
// ID returns the node's public key.
func (p *Peer) ID() discover.NodeID {
return *p.remoteID
}
// Name returns the node name that the remote node advertised.
func (p *Peer) Name() string {
// this needs a lock because the information is part of the
// protocol handshake.
p.infoMu.Lock()
name := p.name
p.infoMu.Unlock()
return name
}
// Caps returns the capabilities (supported subprotocols) of the remote peer.
func (p *Peer) Caps() []Cap {
// this needs a lock because the information is part of the
// protocol handshake.
p.infoMu.Lock()
caps := p.caps
p.infoMu.Unlock()
return caps
}
// RemoteAddr returns the remote address of the network connection.
func (p *Peer) RemoteAddr() net.Addr {
return p.rw.RemoteAddr()
}
// LocalAddr returns the local address of the network connection.
func (p *Peer) LocalAddr() net.Addr {
return p.rw.LocalAddr()
}
// Disconnect terminates the peer connection with the given reason.
// It returns immediately and does not wait until the connection is closed.
func (p *Peer) Disconnect(reason DiscReason) {
select {
case p.disc <- reason:
case <-p.closed:
}
}
// String implements fmt.Stringer.
func (p *Peer) String() string {
return fmt.Sprintf("Peer %.8x %v", p.remoteID[:], p.RemoteAddr())
}
func newPeer(conn net.Conn, protocols []Protocol, ourName string, ourID, remoteID *discover.NodeID) *Peer {
logtag := fmt.Sprintf("Peer %.8x %v", remoteID[:], conn.RemoteAddr())
return &Peer{
Logger: logger.NewLogger(logtag),
rw: newFrameRW(conn, msgWriteTimeout),
ourID: ourID,
ourName: ourName,
remoteID: remoteID,
protocols: protocols,
running: make(map[string]*proto),
disc: make(chan DiscReason),
protoErr: make(chan error),
closed: make(chan struct{}),
}
}
func (p *Peer) setHandshakeInfo(name string, caps []Cap) {
p.infoMu.Lock()
p.name = name
p.caps = caps
p.infoMu.Unlock()
}
func (p *Peer) run() DiscReason {
var readErr = make(chan error, 1)
defer p.closeProtocols()
defer close(p.closed)
go func() { readErr <- p.readLoop() }()
if !p.noHandshake {
if err := writeProtocolHandshake(p.rw, p.ourName, *p.ourID, p.protocols); err != nil {
p.DebugDetailf("Protocol handshake error: %v\n", err)
p.rw.Close()
return DiscProtocolError
}
}
// Wait for an error or disconnect.
var reason DiscReason
select {
case err := <-readErr:
// We rely on protocols to abort if there is a write error. It
// might be more robust to handle them here as well.
p.DebugDetailf("Read error: %v\n", err)
p.rw.Close()
return DiscNetworkError
case err := <-p.protoErr:
reason = discReasonForError(err)
case reason = <-p.disc:
}
p.politeDisconnect(reason)
// Wait for readLoop. It will end because conn is now closed.
<-readErr
p.Debugf("Disconnected: %v\n", reason)
return reason
}
func (p *Peer) politeDisconnect(reason DiscReason) {
done := make(chan struct{})
go func() {
EncodeMsg(p.rw, discMsg, uint(reason))
// Wait for the other side to close the connection.
// Discard any data that they send until then.
io.Copy(ioutil.Discard, p.rw)
close(done)
}()
select {
case <-done:
case <-time.After(disconnectGracePeriod):
}
p.rw.Close()
}
func (p *Peer) readLoop() error {
if !p.noHandshake {
if err := readProtocolHandshake(p, p.rw); err != nil {
return err
}
}
for {
msg, err := p.rw.ReadMsg()
if err != nil {
return err
}
if err = p.handle(msg); err != nil {
return err
}
}
return nil
}
func (p *Peer) handle(msg Msg) error {
switch {
case msg.Code == pingMsg:
msg.Discard()
go EncodeMsg(p.rw, pongMsg)
case msg.Code == discMsg:
var reason DiscReason
// no need to discard or for error checking, we'll close the
// connection after this.
rlp.Decode(msg.Payload, &reason)
p.Disconnect(DiscRequested)
return discRequestedError(reason)
case msg.Code < baseProtocolLength:
// ignore other base protocol messages
return msg.Discard()
default:
// it's a subprotocol message
proto, err := p.getProto(msg.Code)
if err != nil {
return fmt.Errorf("msg code out of range: %v", msg.Code)
}
proto.in <- msg
}
return nil
}
func readProtocolHandshake(p *Peer, rw MsgReadWriter) error {
// read and handle remote handshake
msg, err := rw.ReadMsg()
if err != nil {
return err
}
if msg.Code != handshakeMsg {
return newPeerError(errProtocolBreach, "expected handshake, got %x", msg.Code)
}
if msg.Size > baseProtocolMaxMsgSize {
return newPeerError(errInvalidMsg, "message too big")
}
var hs handshake
if err := msg.Decode(&hs); err != nil {
return err
}
// validate handshake info
if hs.Version != baseProtocolVersion {
return newPeerError(errP2PVersionMismatch, "required version %d, received %d\n",
baseProtocolVersion, hs.Version)
}
if hs.NodeID == *p.remoteID {
return newPeerError(errPubkeyForbidden, "node ID mismatch")
}
// TODO: remove Caps with empty name
p.setHandshakeInfo(hs.Name, hs.Caps)
p.startSubprotocols(hs.Caps)
return nil
}
func writeProtocolHandshake(w MsgWriter, name string, id discover.NodeID, ps []Protocol) error {
var caps []interface{}
for _, proto := range ps {
caps = append(caps, proto.cap())
}
return EncodeMsg(w, handshakeMsg, baseProtocolVersion, name, caps, 0, id)
}
// startProtocols starts matching named subprotocols.
func (p *Peer) startSubprotocols(caps []Cap) {
sort.Sort(capsByName(caps))
p.runlock.Lock()
defer p.runlock.Unlock()
offset := baseProtocolLength
outer:
for _, cap := range caps {
for _, proto := range p.protocols {
if proto.Name == cap.Name &&
proto.Version == cap.Version &&
p.running[cap.Name] == nil {
p.running[cap.Name] = p.startProto(offset, proto)
offset += proto.Length
continue outer
}
}
}
}
func (p *Peer) startProto(offset uint64, impl Protocol) *proto {
p.DebugDetailf("Starting protocol %s/%d\n", impl.Name, impl.Version)
rw := &proto{
name: impl.Name,
in: make(chan Msg),
offset: offset,
maxcode: impl.Length,
w: p.rw,
}
p.protoWG.Add(1)
go func() {
err := impl.Run(p, rw)
if err == nil {
p.DebugDetailf("Protocol %s/%d returned\n", impl.Name, impl.Version)
err = errors.New("protocol returned")
} else {
p.DebugDetailf("Protocol %s/%d error: %v\n", impl.Name, impl.Version, err)
}
select {
case p.protoErr <- err:
case <-p.closed:
}
p.protoWG.Done()
}()
return rw
}
// getProto finds the protocol responsible for handling
// the given message code.
func (p *Peer) getProto(code uint64) (*proto, error) {
p.runlock.RLock()
defer p.runlock.RUnlock()
for _, proto := range p.running {
if code >= proto.offset && code < proto.offset+proto.maxcode {
return proto, nil
}
}
return nil, newPeerError(errInvalidMsgCode, "%d", code)
}
func (p *Peer) closeProtocols() {
p.runlock.RLock()
for _, p := range p.running {
close(p.in)
}
p.runlock.RUnlock()
p.protoWG.Wait()
}
// writeProtoMsg sends the given message on behalf of the given named protocol.
// this exists because of Server.Broadcast.
func (p *Peer) writeProtoMsg(protoName string, msg Msg) error {
p.runlock.RLock()
proto, ok := p.running[protoName]
p.runlock.RUnlock()
if !ok {
return fmt.Errorf("protocol %s not handled by peer", protoName)
}
if msg.Code >= proto.maxcode {
return newPeerError(errInvalidMsgCode, "code %x is out of range for protocol %q", msg.Code, protoName)
}
msg.Code += proto.offset
return p.rw.WriteMsg(msg)
}
type proto struct {
name string
in chan Msg
maxcode, offset uint64
w MsgWriter
}
func (rw *proto) WriteMsg(msg Msg) error {
if msg.Code >= rw.maxcode {
return newPeerError(errInvalidMsgCode, "not handled")
}
msg.Code += rw.offset
return rw.w.WriteMsg(msg)
}
func (rw *proto) ReadMsg() (Msg, error) {
msg, ok := <-rw.in
if !ok {
return msg, io.EOF
}
msg.Code -= rw.offset
return msg, nil
}