lbcd/wire/msgpong.go

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// Copyright (c) 2013-2015 Conformal Systems LLC.
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// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package wire
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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)
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}
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)
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}
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
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}
// 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,
}
}