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.
128 lines
4.8 KiB
Go
128 lines
4.8 KiB
Go
// Copyright (c) 2013-2016 The btcsuite developers
|
|
// Use of this source code is governed by an ISC
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package wire
|
|
|
|
import (
|
|
"bytes"
|
|
"io"
|
|
"time"
|
|
|
|
"github.com/btcsuite/btcd/chaincfg/chainhash"
|
|
)
|
|
|
|
// MaxBlockHeaderPayload is the maximum number of bytes a block header can be.
|
|
// Version 4 bytes + Timestamp 4 bytes + Bits 4 bytes + Nonce 4 bytes +
|
|
// PrevBlock and MerkleRoot hashes.
|
|
const MaxBlockHeaderPayload = 16 + (chainhash.HashSize * 2)
|
|
|
|
// BlockHeader defines information about a block and is used in the bitcoin
|
|
// block (MsgBlock) and headers (MsgHeaders) messages.
|
|
type BlockHeader struct {
|
|
// Version of the block. This is not the same as the protocol version.
|
|
Version int32
|
|
|
|
// Hash of the previous block in the block chain.
|
|
PrevBlock chainhash.Hash
|
|
|
|
// Merkle tree reference to hash of all transactions for the block.
|
|
MerkleRoot chainhash.Hash
|
|
|
|
// Time the block was created. This is, unfortunately, encoded as a
|
|
// uint32 on the wire and therefore is limited to 2106.
|
|
Timestamp time.Time
|
|
|
|
// Difficulty target for the block.
|
|
Bits uint32
|
|
|
|
// Nonce used to generate the block.
|
|
Nonce uint32
|
|
}
|
|
|
|
// blockHeaderLen is a constant that represents the number of bytes for a block
|
|
// header.
|
|
const blockHeaderLen = 80
|
|
|
|
// BlockHash computes the block identifier hash for the given block header.
|
|
func (h *BlockHeader) BlockHash() chainhash.Hash {
|
|
// Encode the header and double sha256 everything prior to the number of
|
|
// transactions. Ignore the error returns since there is no way the
|
|
// encode could fail except being out of memory which would cause a
|
|
// run-time panic.
|
|
buf := bytes.NewBuffer(make([]byte, 0, MaxBlockHeaderPayload))
|
|
_ = writeBlockHeader(buf, 0, h)
|
|
|
|
return chainhash.DoubleHashH(buf.Bytes())
|
|
}
|
|
|
|
// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
|
|
// This is part of the Message interface implementation.
|
|
// See Deserialize for decoding block headers stored to disk, such as in a
|
|
// database, as opposed to decoding block headers from the wire.
|
|
func (h *BlockHeader) BtcDecode(r io.Reader, pver uint32, enc MessageEncoding) error {
|
|
return readBlockHeader(r, pver, h)
|
|
}
|
|
|
|
// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
|
|
// This is part of the Message interface implementation.
|
|
// See Serialize for encoding block headers to be stored to disk, such as in a
|
|
// database, as opposed to encoding block headers for the wire.
|
|
func (h *BlockHeader) BtcEncode(w io.Writer, pver uint32, enc MessageEncoding) error {
|
|
return writeBlockHeader(w, pver, h)
|
|
}
|
|
|
|
// Deserialize decodes a block header from r into the receiver using a format
|
|
// that is suitable for long-term storage such as a database while respecting
|
|
// the Version field.
|
|
func (h *BlockHeader) Deserialize(r io.Reader) error {
|
|
// At the current time, there is no difference between the wire encoding
|
|
// at protocol version 0 and the stable long-term storage format. As
|
|
// a result, make use of readBlockHeader.
|
|
return readBlockHeader(r, 0, h)
|
|
}
|
|
|
|
// Serialize encodes a block header from r into the receiver using a format
|
|
// that is suitable for long-term storage such as a database while respecting
|
|
// the Version field.
|
|
func (h *BlockHeader) Serialize(w io.Writer) error {
|
|
// At the current time, there is no difference between the wire encoding
|
|
// at protocol version 0 and the stable long-term storage format. As
|
|
// a result, make use of writeBlockHeader.
|
|
return writeBlockHeader(w, 0, h)
|
|
}
|
|
|
|
// NewBlockHeader returns a new BlockHeader using the provided version, previous
|
|
// block hash, merkle root hash, difficulty bits, and nonce used to generate the
|
|
// block with defaults for the remaining fields.
|
|
func NewBlockHeader(version int32, prevHash, merkleRootHash *chainhash.Hash,
|
|
bits uint32, nonce uint32) *BlockHeader {
|
|
|
|
// Limit the timestamp to one second precision since the protocol
|
|
// doesn't support better.
|
|
return &BlockHeader{
|
|
Version: version,
|
|
PrevBlock: *prevHash,
|
|
MerkleRoot: *merkleRootHash,
|
|
Timestamp: time.Unix(time.Now().Unix(), 0),
|
|
Bits: bits,
|
|
Nonce: nonce,
|
|
}
|
|
}
|
|
|
|
// readBlockHeader reads a bitcoin block header from r. See Deserialize for
|
|
// decoding block headers stored to disk, such as in a database, as opposed to
|
|
// decoding from the wire.
|
|
func readBlockHeader(r io.Reader, pver uint32, bh *BlockHeader) error {
|
|
return readElements(r, &bh.Version, &bh.PrevBlock, &bh.MerkleRoot,
|
|
(*uint32Time)(&bh.Timestamp), &bh.Bits, &bh.Nonce)
|
|
}
|
|
|
|
// writeBlockHeader writes a bitcoin block header to w. See Serialize for
|
|
// encoding block headers to be stored to disk, such as in a database, as
|
|
// opposed to encoding for the wire.
|
|
func writeBlockHeader(w io.Writer, pver uint32, bh *BlockHeader) error {
|
|
sec := uint32(bh.Timestamp.Unix())
|
|
return writeElements(w, bh.Version, &bh.PrevBlock, &bh.MerkleRoot,
|
|
sec, bh.Bits, bh.Nonce)
|
|
}
|