forked from cerc-io/plugeth
64564da20b
The previous limit was 10MB which is unacceptable for all kinds of reasons, the most important one being that we don't want to allow the remote side to make us allocate 10MB at handshake time.
301 lines
6.8 KiB
Go
301 lines
6.8 KiB
Go
package p2p
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import (
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"errors"
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"fmt"
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"io"
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"net"
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"sort"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/logger"
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"github.com/ethereum/go-ethereum/logger/glog"
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"github.com/ethereum/go-ethereum/p2p/discover"
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"github.com/ethereum/go-ethereum/rlp"
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)
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const (
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baseProtocolVersion = 4
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baseProtocolLength = uint64(16)
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baseProtocolMaxMsgSize = 2 * 1024
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pingInterval = 15 * time.Second
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)
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const (
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// devp2p message codes
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handshakeMsg = 0x00
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discMsg = 0x01
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pingMsg = 0x02
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pongMsg = 0x03
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getPeersMsg = 0x04
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peersMsg = 0x05
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)
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// Peer represents a connected remote node.
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type Peer struct {
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conn net.Conn
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rw *conn
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running map[string]*protoRW
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wg sync.WaitGroup
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protoErr chan error
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closed chan struct{}
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disc chan DiscReason
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}
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// NewPeer returns a peer for testing purposes.
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func NewPeer(id discover.NodeID, name string, caps []Cap) *Peer {
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pipe, _ := net.Pipe()
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msgpipe, _ := MsgPipe()
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conn := &conn{msgpipe, &protoHandshake{ID: id, Name: name, Caps: caps}}
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peer := newPeer(pipe, conn, nil)
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close(peer.closed) // ensures Disconnect doesn't block
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return peer
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}
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// ID returns the node's public key.
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func (p *Peer) ID() discover.NodeID {
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return p.rw.ID
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}
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// Name returns the node name that the remote node advertised.
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func (p *Peer) Name() string {
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return p.rw.Name
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}
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// Caps returns the capabilities (supported subprotocols) of the remote peer.
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func (p *Peer) Caps() []Cap {
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// TODO: maybe return copy
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return p.rw.Caps
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}
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// RemoteAddr returns the remote address of the network connection.
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func (p *Peer) RemoteAddr() net.Addr {
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return p.conn.RemoteAddr()
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}
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// LocalAddr returns the local address of the network connection.
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func (p *Peer) LocalAddr() net.Addr {
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return p.conn.LocalAddr()
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}
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// Disconnect terminates the peer connection with the given reason.
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// It returns immediately and does not wait until the connection is closed.
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func (p *Peer) Disconnect(reason DiscReason) {
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select {
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case p.disc <- reason:
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case <-p.closed:
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}
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}
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// String implements fmt.Stringer.
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func (p *Peer) String() string {
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return fmt.Sprintf("Peer %.8x %v", p.rw.ID[:], p.RemoteAddr())
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}
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func newPeer(fd net.Conn, conn *conn, protocols []Protocol) *Peer {
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protomap := matchProtocols(protocols, conn.Caps, conn)
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p := &Peer{
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conn: fd,
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rw: conn,
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running: protomap,
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disc: make(chan DiscReason),
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protoErr: make(chan error, len(protomap)+1), // protocols + pingLoop
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closed: make(chan struct{}),
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}
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return p
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}
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func (p *Peer) run() DiscReason {
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readErr := make(chan error, 1)
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p.wg.Add(2)
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go p.readLoop(readErr)
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go p.pingLoop()
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p.startProtocols()
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// Wait for an error or disconnect.
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var reason DiscReason
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select {
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case err := <-readErr:
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if r, ok := err.(DiscReason); ok {
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reason = r
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} else {
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// Note: We rely on protocols to abort if there is a write
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// error. It might be more robust to handle them here as well.
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glog.V(logger.Detail).Infof("%v: Read error: %v\n", p, err)
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reason = DiscNetworkError
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}
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case err := <-p.protoErr:
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reason = discReasonForError(err)
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case reason = <-p.disc:
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p.politeDisconnect(reason)
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reason = DiscRequested
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}
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close(p.closed)
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p.wg.Wait()
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glog.V(logger.Debug).Infof("%v: Disconnected: %v\n", p, reason)
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return reason
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}
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func (p *Peer) politeDisconnect(reason DiscReason) {
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if reason != DiscNetworkError {
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SendItems(p.rw, discMsg, uint(reason))
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}
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p.conn.Close()
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}
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func (p *Peer) pingLoop() {
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ping := time.NewTicker(pingInterval)
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defer p.wg.Done()
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defer ping.Stop()
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for {
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select {
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case <-ping.C:
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if err := SendItems(p.rw, pingMsg); err != nil {
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p.protoErr <- err
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return
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}
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case <-p.closed:
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return
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}
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}
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}
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func (p *Peer) readLoop(errc chan<- error) {
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defer p.wg.Done()
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for {
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msg, err := p.rw.ReadMsg()
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if err != nil {
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errc <- err
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return
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}
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msg.ReceivedAt = time.Now()
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if err = p.handle(msg); err != nil {
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errc <- err
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return
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}
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}
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}
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func (p *Peer) handle(msg Msg) error {
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switch {
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case msg.Code == pingMsg:
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msg.Discard()
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go SendItems(p.rw, pongMsg)
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case msg.Code == discMsg:
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var reason [1]DiscReason
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// This is the last message. We don't need to discard or
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// check errors because, the connection will be closed after it.
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rlp.Decode(msg.Payload, &reason)
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glog.V(logger.Debug).Infof("%v: Disconnect Requested: %v\n", p, reason[0])
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return reason[0]
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case msg.Code < baseProtocolLength:
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// ignore other base protocol messages
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return msg.Discard()
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default:
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// it's a subprotocol message
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proto, err := p.getProto(msg.Code)
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if err != nil {
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return fmt.Errorf("msg code out of range: %v", msg.Code)
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}
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select {
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case proto.in <- msg:
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return nil
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case <-p.closed:
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return io.EOF
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}
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}
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return nil
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}
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func countMatchingProtocols(protocols []Protocol, caps []Cap) int {
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n := 0
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for _, cap := range caps {
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for _, proto := range protocols {
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if proto.Name == cap.Name && proto.Version == cap.Version {
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n++
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}
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}
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}
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return n
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}
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// matchProtocols creates structures for matching named subprotocols.
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func matchProtocols(protocols []Protocol, caps []Cap, rw MsgReadWriter) map[string]*protoRW {
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sort.Sort(capsByName(caps))
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offset := baseProtocolLength
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result := make(map[string]*protoRW)
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outer:
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for _, cap := range caps {
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for _, proto := range protocols {
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if proto.Name == cap.Name && proto.Version == cap.Version && result[cap.Name] == nil {
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result[cap.Name] = &protoRW{Protocol: proto, offset: offset, in: make(chan Msg), w: rw}
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offset += proto.Length
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continue outer
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}
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}
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}
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return result
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}
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func (p *Peer) startProtocols() {
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p.wg.Add(len(p.running))
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for _, proto := range p.running {
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proto := proto
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proto.closed = p.closed
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glog.V(logger.Detail).Infof("%v: Starting protocol %s/%d\n", p, proto.Name, proto.Version)
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go func() {
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err := proto.Run(p, proto)
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if err == nil {
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glog.V(logger.Detail).Infof("%v: Protocol %s/%d returned\n", p, proto.Name, proto.Version)
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err = errors.New("protocol returned")
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} else if err != io.EOF {
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glog.V(logger.Detail).Infof("%v: Protocol %s/%d error: \n", p, proto.Name, proto.Version, err)
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}
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p.protoErr <- err
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p.wg.Done()
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}()
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}
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}
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// getProto finds the protocol responsible for handling
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// the given message code.
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func (p *Peer) getProto(code uint64) (*protoRW, error) {
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for _, proto := range p.running {
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if code >= proto.offset && code < proto.offset+proto.Length {
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return proto, nil
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}
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}
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return nil, newPeerError(errInvalidMsgCode, "%d", code)
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}
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type protoRW struct {
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Protocol
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in chan Msg
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closed <-chan struct{}
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offset uint64
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w MsgWriter
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}
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func (rw *protoRW) WriteMsg(msg Msg) error {
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if msg.Code >= rw.Length {
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return newPeerError(errInvalidMsgCode, "not handled")
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}
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msg.Code += rw.offset
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return rw.w.WriteMsg(msg)
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}
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func (rw *protoRW) ReadMsg() (Msg, error) {
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select {
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case msg := <-rw.in:
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msg.Code -= rw.offset
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return msg, nil
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case <-rw.closed:
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return Msg{}, io.EOF
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}
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}
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