48abfdf87c
This commit modifies the existing wire.Message interface to introduce a new MessageEncoding variant which dictates the exact encoding to be used when serializing and deserializing messages. Such an option is now necessary due to the segwit soft-fork package, as btcd will need to be able to optionally encode transactions/blocks without witness data to un-upgraded peers. Two new functions have been introduced: ReadMessageWithEncodingN and WriteMessageWithEncodingN which wrap BtcDecode/BtcEncode with the desired encoding format.
88 lines
2.6 KiB
Go
88 lines
2.6 KiB
Go
// Copyright (c) 2013-2015 The btcsuite developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package wire
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import (
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"io"
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)
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// MsgPing implements the Message interface and represents a bitcoin ping
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// message.
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//
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// For versions BIP0031Version and earlier, it is used primarily to confirm
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// that a connection is still valid. A transmission error is typically
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// interpreted as a closed connection and that the peer should be removed.
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// For versions AFTER BIP0031Version it contains an identifier which can be
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// returned in the pong message to determine network timing.
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//
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// The payload for this message just consists of a nonce used for identifying
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// it later.
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type MsgPing struct {
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// Unique value associated with message that is used to identify
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// specific ping message.
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Nonce uint64
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}
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// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
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// This is part of the Message interface implementation.
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func (msg *MsgPing) BtcDecode(r io.Reader, pver uint32, enc MessageEncoding) error {
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// There was no nonce for BIP0031Version and earlier.
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// NOTE: > is not a mistake here. The BIP0031 was defined as AFTER
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// the version unlike most others.
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if pver > BIP0031Version {
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err := readElement(r, &msg.Nonce)
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if err != nil {
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return err
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}
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}
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return nil
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}
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// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
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// This is part of the Message interface implementation.
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func (msg *MsgPing) BtcEncode(w io.Writer, pver uint32, enc MessageEncoding) error {
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// There was no nonce for BIP0031Version and earlier.
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// NOTE: > is not a mistake here. The BIP0031 was defined as AFTER
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// the version unlike most others.
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if pver > BIP0031Version {
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err := writeElement(w, msg.Nonce)
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if err != nil {
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return err
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}
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}
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return nil
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}
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// Command returns the protocol command string for the message. This is part
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// of the Message interface implementation.
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func (msg *MsgPing) Command() string {
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return CmdPing
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}
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// MaxPayloadLength returns the maximum length the payload can be for the
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// receiver. This is part of the Message interface implementation.
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func (msg *MsgPing) MaxPayloadLength(pver uint32) uint32 {
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plen := uint32(0)
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// There was no nonce for BIP0031Version and earlier.
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// NOTE: > is not a mistake here. The BIP0031 was defined as AFTER
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// the version unlike most others.
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if pver > BIP0031Version {
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// Nonce 8 bytes.
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plen += 8
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}
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return plen
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}
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// NewMsgPing returns a new bitcoin ping message that conforms to the Message
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// interface. See MsgPing for details.
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func NewMsgPing(nonce uint64) *MsgPing {
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return &MsgPing{
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Nonce: nonce,
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}
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}
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