btcd/msgpong.go
Dave Collins 4deb922c9d Export command constants.
Although it is possible to get the command name for each msg type by
creating an instances of the type and calling the Command method against
it, it's slightly more efficient to simply allows callers to have direct
access to the exported constants.

This is currently really useful for the reject message since callers need
to be able to examine the command type to determine whether or not the
hash field needs to be included.
2014-07-14 10:38:29 -05:00

89 lines
2.5 KiB
Go

// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package btcwire
import (
"fmt"
"io"
)
// MsgPong implements the Message interface and represents a bitcoin pong
// message which is used primarily to confirm that a connection is still valid
// in response to a bitcoin ping message (MsgPing).
//
// This message was not added until protocol versions AFTER BIP0031Version.
type MsgPong struct {
// Unique value associated with message that is used to identify
// specific ping message.
Nonce uint64
}
// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
// This is part of the Message interface implementation.
func (msg *MsgPong) BtcDecode(r io.Reader, pver uint32) error {
// NOTE: <= is not a mistake here. The BIP0031 was defined as AFTER
// the version unlike most others.
if pver <= BIP0031Version {
str := fmt.Sprintf("pong message invalid for protocol "+
"version %d", pver)
return messageError("MsgPong.BtcDecode", str)
}
err := readElement(r, &msg.Nonce)
if err != nil {
return err
}
return nil
}
// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
// This is part of the Message interface implementation.
func (msg *MsgPong) BtcEncode(w io.Writer, pver uint32) error {
// NOTE: <= is not a mistake here. The BIP0031 was defined as AFTER
// the version unlike most others.
if pver <= BIP0031Version {
str := fmt.Sprintf("pong message invalid for protocol "+
"version %d", pver)
return messageError("MsgPong.BtcEncode", str)
}
err := writeElement(w, msg.Nonce)
if err != nil {
return err
}
return nil
}
// Command returns the protocol command string for the message. This is part
// of the Message interface implementation.
func (msg *MsgPong) Command() string {
return CmdPong
}
// MaxPayloadLength returns the maximum length the payload can be for the
// receiver. This is part of the Message interface implementation.
func (msg *MsgPong) MaxPayloadLength(pver uint32) uint32 {
plen := uint32(0)
// The pong message did not exist for BIP0031Version and earlier.
// NOTE: > is not a mistake here. The BIP0031 was defined as AFTER
// the version unlike most others.
if pver > BIP0031Version {
// Nonce 8 bytes.
plen += 8
}
return plen
}
// NewMsgPong returns a new bitcoin pong message that conforms to the Message
// interface. See MsgPong for details.
func NewMsgPong(nonce uint64) *MsgPong {
return &MsgPong{
Nonce: nonce,
}
}