handshake.go

   1 package torrent
   2
   3 import (
   4         "bytes"
   5         "fmt"
   6         "io"
   7         "net"
   8         "time"
   9
  10         "github.com/anacrolix/torrent/mse"
  11         pp "github.com/anacrolix/torrent/peer_protocol"
  12 )
  13
  14 // Wraps a raw connection and provides the interface we want for using the
  15 // connection in the message loop.
  16 type deadlineReader struct {
  17         nc net.Conn
  18         r  io.Reader
  19 }
  20
  21 func (r deadlineReader) Read(b []byte) (int, error) {
  22         // Keep-alives should be received every 2 mins. Give a bit of gracetime.
  23         err := r.nc.SetReadDeadline(time.Now().Add(150 * time.Second))
  24         if err != nil {
  25                 return 0, fmt.Errorf("error setting read deadline: %s", err)
  26         }
  27         return r.r.Read(b)
  28 }
  29
  30 func handleEncryption(
  31         rw io.ReadWriter,
  32         skeys mse.SecretKeyIter,
  33         policy HeaderObfuscationPolicy,
  34         selector mse.CryptoSelector,
  35 ) (
  36         ret io.ReadWriter,
  37         headerEncrypted bool,
  38         cryptoMethod mse.CryptoMethod,
  39         err error,
  40 ) {
  41         if !policy.RequirePreferred || !policy.Preferred {
  42                 var protocol [len(pp.Protocol)]byte
  43                 _, err = io.ReadFull(rw, protocol[:])
  44                 if err != nil {
  45                         return
  46                 }
  47                 rw = struct {
  48                         io.Reader
  49                         io.Writer
  50                 }{
  51                         io.MultiReader(bytes.NewReader(protocol[:]), rw),
  52                         rw,
  53                 }
  54                 if string(protocol[:]) == pp.Protocol {
  55                         ret = rw
  56                         return
  57                 }
  58                 if policy.RequirePreferred {
  59                         err = fmt.Errorf("unexpected protocol string %q and header obfuscation disabled", protocol)
  60                         return
  61                 }
  62         }
  63         headerEncrypted = true
  64         ret, cryptoMethod, err = mse.ReceiveHandshake(rw, skeys, selector)
  65         return
  66 }
  67
  68 type PeerExtensionBits = pp.PeerExtensionBits