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118 lines
2.5 KiB
118 lines
2.5 KiB
package p2p
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import (
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"bytes"
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"errors"
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"io"
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. "github.com/tendermint/tendermint/binary"
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)
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var pexErrInvalidMessage = errors.New("Invalid PEX message")
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const pexCh = "PEX"
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/*
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The PexHandler routine should be started separately from the Switch.
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It handles basic PEX communciation.
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The application is responsible for sending out a PexRequestMessage.
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*/
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func PexHandler(s *Switch, addrBook *AddrBook) {
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for {
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inPkt := s.Receive(pexCh) // {Peer, Time, Packet}
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if inPkt == nil {
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// Client has stopped
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break
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}
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// decode message
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msg := decodeMessage(inPkt.Bytes)
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switch msg.(type) {
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case *PexRequestMessage:
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// inPkt.Peer requested some peers.
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// TODO: prevent abuse.
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addrs := addrBook.GetSelection()
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response := &pexResponseMessage{Addrs: addrs}
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pkt := NewPacket(pexCh, BinaryBytes(response))
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queued := inPkt.Peer.TryQueue(pkt)
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if !queued {
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// ignore
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}
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case *pexResponseMessage:
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// We received some peer addresses from inPkt.Peer.
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// TODO: prevent abuse.
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// (We don't want to get spammed with bad peers)
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srcAddr := inPkt.Peer.RemoteAddress()
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for _, addr := range msg.(*pexResponseMessage).Addrs {
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addrBook.AddAddress(addr, srcAddr)
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}
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default:
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// Bad peer.
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s.StopPeerForError(inPkt.Peer, pexErrInvalidMessage)
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}
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}
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// cleanup
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}
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/* Messages */
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const (
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pexTypeUnknown = Byte(0x00)
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pexTypeRequest = Byte(0x01)
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pexTypeResponse = Byte(0x02)
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)
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// TODO: check for unnecessary extra bytes at the end.
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func decodeMessage(bz ByteSlice) (msg Message) {
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switch Byte(bz[0]) {
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case pexTypeRequest:
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return &PexRequestMessage{}
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case pexTypeResponse:
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return readPexResponseMessage(bytes.NewReader(bz[1:]))
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default:
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return nil
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}
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}
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/*
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A response with peer addresses
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*/
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type PexRequestMessage struct {
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}
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func (m *PexRequestMessage) WriteTo(w io.Writer) (n int64, err error) {
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n, err = WriteOnto(pexTypeRequest, w, n, err)
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return
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}
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/*
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A response with peer addresses
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*/
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type pexResponseMessage struct {
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Addrs []*NetAddress
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}
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func readPexResponseMessage(r io.Reader) *pexResponseMessage {
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numAddrs := int(ReadUInt32(r))
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addrs := []*NetAddress{}
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for i := 0; i < numAddrs; i++ {
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addr := ReadNetAddress(r)
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addrs = append(addrs, addr)
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}
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return &pexResponseMessage{
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Addrs: addrs,
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}
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}
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func (m *pexResponseMessage) WriteTo(w io.Writer) (n int64, err error) {
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n, err = WriteOnto(pexTypeResponse, w, n, err)
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n, err = WriteOnto(UInt32(len(m.Addrs)), w, n, err)
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for _, addr := range m.Addrs {
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n, err = WriteOnto(addr, w, n, err)
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}
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return
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}
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