torrent/handshake.go

75 lines
1.6 KiB
Go

package torrent
import (
"bytes"
"fmt"
"io"
"net"
"time"
"github.com/anacrolix/torrent/mse"
pp "github.com/anacrolix/torrent/peer_protocol"
)
// Wraps a raw connection and provides the interface we want for using the
// connection in the message loop.
type deadlineReader struct {
nc net.Conn
r io.Reader
}
func (r deadlineReader) Read(b []byte) (int, error) {
// Keep-alives should be received every 2 mins. Give a bit of gracetime.
err := r.nc.SetReadDeadline(time.Now().Add(150 * time.Second))
if err != nil {
return 0, fmt.Errorf("error setting read deadline: %s", err)
}
return r.r.Read(b)
}
func handleEncryption(
rw io.ReadWriter,
skeys mse.SecretKeyIter,
policy EncryptionPolicy,
) (
ret io.ReadWriter,
headerEncrypted bool,
cryptoMethod mse.CryptoMethod,
err error,
) {
if !policy.ForceEncryption {
var protocol [len(pp.Protocol)]byte
_, err = io.ReadFull(rw, protocol[:])
if err != nil {
return
}
rw = struct {
io.Reader
io.Writer
}{
io.MultiReader(bytes.NewReader(protocol[:]), rw),
rw,
}
if string(protocol[:]) == pp.Protocol {
ret = rw
return
}
}
headerEncrypted = true
ret, cryptoMethod, err = mse.ReceiveHandshake(rw, skeys, func(provides mse.CryptoMethod) mse.CryptoMethod {
switch {
case policy.ForceEncryption:
return mse.CryptoMethodRC4
case policy.DisableEncryption:
return mse.CryptoMethodPlaintext
case policy.PreferNoEncryption && provides&mse.CryptoMethodPlaintext != 0:
return mse.CryptoMethodPlaintext
default:
return mse.DefaultCryptoSelector(provides)
}
})
return
}
type PeerExtensionBits = pp.PeerExtensionBits