erigon-pulse/p2p/peer.go
Felix Lange 5ba51594c7 p2p: use package rlp to encode messages
Message encoding functions have been renamed to catch any uses.
The switch to the new encoder can cause subtle incompatibilities.
If there are any users outside of our tree, they will at least be
alerted that there was a change.

NewMsg no longer exists. The replacements for EncodeMsg are called
Send and SendItems.
2015-03-19 15:11:02 +01:00

313 lines
7.2 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 = 3
baseProtocolLength = uint64(16)
baseProtocolMaxMsgSize = 10 * 1024 * 1024
pingInterval = 15 * time.Second
disconnectGracePeriod = 2 * time.Second
)
const (
// devp2p message codes
handshakeMsg = 0x00
discMsg = 0x01
pingMsg = 0x02
pongMsg = 0x03
getPeersMsg = 0x04
peersMsg = 0x05
)
// 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
conn net.Conn
rw *conn
running map[string]*protoRW
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 {
pipe, _ := net.Pipe()
msgpipe, _ := MsgPipe()
conn := &conn{msgpipe, &protoHandshake{ID: id, Name: name, Caps: caps}}
peer := newPeer(pipe, conn, nil)
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.rw.ID
}
// Name returns the node name that the remote node advertised.
func (p *Peer) Name() string {
return p.rw.Name
}
// Caps returns the capabilities (supported subprotocols) of the remote peer.
func (p *Peer) Caps() []Cap {
// TODO: maybe return copy
return p.rw.Caps
}
// RemoteAddr returns the remote address of the network connection.
func (p *Peer) RemoteAddr() net.Addr {
return p.conn.RemoteAddr()
}
// LocalAddr returns the local address of the network connection.
func (p *Peer) LocalAddr() net.Addr {
return p.conn.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.rw.ID[:], p.RemoteAddr())
}
func newPeer(fd net.Conn, conn *conn, protocols []Protocol) *Peer {
logtag := fmt.Sprintf("Peer %.8x %v", conn.ID[:], fd.RemoteAddr())
p := &Peer{
Logger: logger.NewLogger(logtag),
conn: fd,
rw: conn,
running: matchProtocols(protocols, conn.Caps, conn),
disc: make(chan DiscReason),
protoErr: make(chan error),
closed: make(chan struct{}),
}
return p
}
func (p *Peer) run() DiscReason {
var readErr = make(chan error, 1)
defer p.closeProtocols()
defer close(p.closed)
p.startProtocols()
go func() { readErr <- p.readLoop() }()
ping := time.NewTicker(pingInterval)
defer ping.Stop()
// Wait for an error or disconnect.
var reason DiscReason
loop:
for {
select {
case <-ping.C:
go func() {
if err := SendItems(p.rw, pingMsg); err != nil {
p.protoErr <- err
return
}
}()
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.conn.Close()
return DiscNetworkError
case err := <-p.protoErr:
reason = discReasonForError(err)
break loop
case reason = <-p.disc:
break loop
}
}
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() {
SendItems(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.conn)
close(done)
}()
select {
case <-done:
case <-time.After(disconnectGracePeriod):
}
p.conn.Close()
}
func (p *Peer) readLoop() error {
for {
p.conn.SetDeadline(time.Now().Add(frameReadTimeout))
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 SendItems(p.rw, pongMsg)
case msg.Code == discMsg:
var reason [1]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[0])
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
}
// matchProtocols creates structures for matching named subprotocols.
func matchProtocols(protocols []Protocol, caps []Cap, rw MsgReadWriter) map[string]*protoRW {
sort.Sort(capsByName(caps))
offset := baseProtocolLength
result := make(map[string]*protoRW)
outer:
for _, cap := range caps {
for _, proto := range protocols {
if proto.Name == cap.Name && proto.Version == cap.Version && result[cap.Name] == nil {
result[cap.Name] = &protoRW{Protocol: proto, offset: offset, in: make(chan Msg), w: rw}
offset += proto.Length
continue outer
}
}
}
return result
}
func (p *Peer) startProtocols() {
for _, proto := range p.running {
proto := proto
p.DebugDetailf("Starting protocol %s/%d\n", proto.Name, proto.Version)
p.protoWG.Add(1)
go func() {
err := proto.Run(p, proto)
if err == nil {
p.DebugDetailf("Protocol %s/%d returned\n", proto.Name, proto.Version)
err = errors.New("protocol returned")
} else {
p.DebugDetailf("Protocol %s/%d error: %v\n", proto.Name, proto.Version, err)
}
select {
case p.protoErr <- err:
case <-p.closed:
}
p.protoWG.Done()
}()
}
}
// getProto finds the protocol responsible for handling
// the given message code.
func (p *Peer) getProto(code uint64) (*protoRW, error) {
for _, proto := range p.running {
if code >= proto.offset && code < proto.offset+proto.Length {
return proto, nil
}
}
return nil, newPeerError(errInvalidMsgCode, "%d", code)
}
func (p *Peer) closeProtocols() {
for _, p := range p.running {
close(p.in)
}
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 {
proto, ok := p.running[protoName]
if !ok {
return fmt.Errorf("protocol %s not handled by peer", protoName)
}
if msg.Code >= proto.Length {
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 protoRW struct {
Protocol
in chan Msg
offset uint64
w MsgWriter
}
func (rw *protoRW) WriteMsg(msg Msg) error {
if msg.Code >= rw.Length {
return newPeerError(errInvalidMsgCode, "not handled")
}
msg.Code += rw.offset
return rw.w.WriteMsg(msg)
}
func (rw *protoRW) ReadMsg() (Msg, error) {
msg, ok := <-rw.in
if !ok {
return msg, io.EOF
}
msg.Code -= rw.offset
return msg, nil
}