This commit implements the new block validation rules as defined by
BIP0141. The new rules include the constraints that if a block has
transactions with witness data, then there MUST be a commitment within
the conies transaction to the root of a new merkle tree which commits
to the wtxid of all transactions. Additionally, rather than limiting
the size of a block by size in bytes, blocks are now limited by their
total weight unit. Similarly, a newly define “sig op cost” is now used
to limit the signature validation cost of transactions found within
blocks.
This commit implements the new “weight” metric introduced as part of
the segwit soft-fork. Post-fork activation, rather than limiting the
size of blocks and transactions based purely on serialized size, a new
metric “weight” will instead be used as a way to more accurately
reflect the costs of a tx/block on the system. With blocks constrained
by weight, the maximum block-size increases to ~4MB.
This commit adds verification of the post-segwit standardness
requirement that all pubkeys involved in checks operations MUST be
serialized as compressed public keys. A new ScriptFlag has been added
to guard this behavior when executing scripts.
This commit modifies the op-code execution for OP_IF and OP_NOTIF to
enforce the additional “minimal if” constraints which require the
top-stack item when the op codes are encountered to be either an empty
vector, or exactly [0x01].
This commit adds a new function to btcec: IsCompressedPubKey. This
function returns true iff the passed serialized public key is encoded
in compressed format.
This commit implements the flag activation portion of BIP 0147. The
verification behavior triggered by the NULLDUMMY script verification
flag has been present within btcd for some time, however it wasn’t
activated by default.
With this commit, once segwit has activated, the ScriptStrictMultiSig
will also be activated within the Script VM. Additionally, the
ScriptStrictMultiSig is now a standard script verification flag which
is used unconditionally within the mempool.
This commit implements full witness program validation for the
currently defined version 0 witness programs. This includes validation
logic for nested p2sh, p2wsh, and p2wkh. Additionally, when in witness
validation mode, an additional set of constrains are enforced such as
using the new sighash digest algorithm and enforcing clean stack
behavior within witness programs.
This commit fixes an off-by-one error which is only manifested by the
new behavior of OP_CODESEPARATOR within sig hashes triggered by the
segwit behavior. The current behavior within the Script VM
(txscript.Engine) is known to be fully correct to the extent that it has
been verified. However, once segwit activates a consensus divergence
would emerge due to *when* the program counter was incremented in the
previous code (pre-this-commit).
Currently (pre-segwit) when calculating the pre-image to a transaction
sighash for signature verification, *all* instances of OP_CODESEPARATOR
are removed from the subScript being signed before generating the final
sighash. SegWit has additional nerfed the behavior of OP_CODESEPARATOR
by no longer removing them (and starting after the last instance), but
instead simply starting the subScript to be directly *after* the last
instance of an OP_CODESEPARATOR within the pkScript.
Due to this new behavior, without this commit, an off-by-one error
(which only matters post-segwit), would cause txscript to generate an
incorrect subScript since the instance of OP_CODESEPARATOR would remain
as part of the subScript instead of being sliced off as the new behavior
dictates. The off-by-one error itself is manifested due to a slight
divergence in txscript.Engine’s logic compared to Bitcoin Core. In
Bitcoin Core script verification is as follows: first the next op-code
is fetched, then program counter is incremented, and finally the op-code
itself is executed. Before this commit, btcd flipped the order
of the last two steps, executing the op-code *before* the program
counter was incremented.
This commit fixes the post-segwit consensus divergence by incrementing
the program-counter *before* the next op-code is executed. It is
important to note that this divergence is only significant post-segwit,
meaning that txscript.Engine is still consensus compliant independent of
this commit.
This commit introduces a series of internal and external helper
functions which enable the txscript package to be aware of the new
standard script templates introduced as part of BIP0141. The two new
standard script templates recognized are pay-to-witness-key-hash
(P2WKH) and pay-to-witness-script-hash (P2WSH).
This commit implements most of BIP0143 by adding logic to implement the
new sighash calculation, signing, and additionally introduces the
HashCache optimization which eliminates the O(N^2) computational
complexity for the SIGHASH_ALL sighash type.
The HashCache struct is the equivalent to the existing SigCache struct,
but for caching the reusable midstate for transactions which are
spending segwitty outputs.
This commit modifies the logic within the block manager and service to
preferentially fetch transactions and blocks which include witness data
from fully upgraded peers.
Once the initial version handshake has completed, the server now tracks
which of the connected peers are witness enabled (they advertise
SFNodeWitness). From then on, if a peer is witness enabled, then btcd
will always request full witness data when fetching
transactions/blocks.
This commit modifies the base peer struct to ascertain when a peer is
able to understand the new witness encoding, and specify the peer’s
supported encoding explicitly before/after the version handshake.
This commit implements the new witness encoding/decoding for
transactions as specified by BIP0144. After segwit activation, a
special transaction encoding is used to signal to upgraded nodes that
the transaction being deserialized bares witness data. The prior
BtcEncode and BtcDecode methods have been extended to be aware of the
new signaling bytes and the encoding of witness data within
transactions.
Additionally, a new method has been added to calculate the “stripped
size” of a transaction/block which is defined as the size of a
transaction/block *excluding* any witness data.
This commit adds the new inventory types for segwit which are used by
the responder to explicitly request that transactions/blocks sent for a
particular inv hash should include all witness data.
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.
This commit introduces the new SFNodeWitness service bit which has been
added to the protocol as part of BIP0144. The new service bit allows
peers on the network to signal their acceptance and adherence to the
new rules defined as part of the segwit soft-fork package.
The IsBech32SegwitPrefix method takes a string prefix and
determines if it is a valid prefix for a Bech32 encoded segwit
address for any of the default or registered networks.
Version 0.15.0 of Bitcoin Core will include a new RPC command that will
allow us to obtain the amount of time (in seconds) that the server has
been running.
This modifies the goclean.sh script that is executed on Travis to
only run the tests without the race detector.
While it is nice to run the race detector on the tests, unfortunately
there is a limit to the number of goroutines that can be launched while
running it. Since Travis is now much slower than it once was, this
causes a ton of false positive failures.
This corrects the assertion in the decodeSpentTxOut function so it does
not improperly cause a panic when unwinding transactions during a reorg
under certain circumstances. In particular, the provided transaction
version that is passed when a stxo entry does not exist is now -1 in
order to properly distinguish it from the zero value.
It also updates the tests accordingly.
This was discovered by the reorg on testnet from block
00000000000018c58c2d2816f03dac327d975a18af6edf1a369df67ecddaf816 to
0000000000001c1161a367156465cc6226e9f862d9c585f94db5779fdf5455ff.
The btclog package has been changed to defining its own logging
interface (rather than seelog's) and provides a default implementation
for callers to use.
There are two primary advantages to the new logger implementation.
First, all log messages are created before the call returns. Compared
to seelog, this prevents data races when mutable variables are logged.
Second, the new logger does not implement any kind of artifical rate
limiting (what seelog refers to as "adaptive logging"). Log messages
are outputted as soon as possible and the application will appear to
perform much better when watching standard output.
Because log rotation is not a feature of the btclog logging
implementation, it is handled by the main package by importing a file
rotation package that provides an io.Reader interface for creating
output to a rotating file output. The rotator has been configured
with the same defaults that btcd previously used in the seelog config
(10MB file limits with maximum of 3 rolls) but now compresses newly
created roll files. Due to the high compressibility of log text, the
compressed files typically reduce to around 15-30% of the original
10MB file.
This slightly optimizes the NAF function by avoiding returning the
unused bit when there is not a carry.
It also adds a bunch of additional unit tests which I made while
debugging.
This modifies the normalize function of the internal field value to
both optimize it and address an issue where the reduction could
lead to an incorrect result with a small range of values. It also adds
tests to ensure the behavior is correct.
The following benchmark shows the relative speedups as a result of the
optimization on my system. In particular, the changes result in
approximately a 14% speedup in Normalize, which ultimately translates to
a 2% speedup in signature verifies.
benchmark old ns/op new ns/op delta
--------------------------------------------------------------------
BenchmarkAddJacobian 1364 1289 -5.50%
BenchmarkAddJacobianNotZOne 3150 3091 -1.87%
BenchmarkScalarBaseMult 134117 132816 -0.97%
BenchmarkScalarBaseMultLarge 135067 132966 -1.56%
BenchmarkScalarMult 411218 402217 -2.19%
BenchmarkSigVerify 671585 657833 -2.05%
BenchmarkFieldNormalize 36.0 31.0 -13.89%
The github markdown interpreter has been changed such that it no longer
allows spaces in between the brackets and parenthesis of links and now
requires a newline in between anchors and other formatting. This
updates all of the markdown files accordingly.
While here, it also corrects a couple of inconsistencies in some of the
README.md files.
This updates the GetNetworkInfoResult structure to include the latest
fields added to Core for compatibility purposes.
While here, also move the definitions of the subtypes for the result
before their use for consistency.
This changes the nonce generated to detect self connections over to use
pseudo randoms instead of a cryptographically random nonce.
There is really not a good reason for it to be cryptographically strong,
using the prng is much faster, and the prng also doesn't burn entropy.
This removes the field that tracks whether the version has been sent
since it is no longer used after the version negotiation was separated
from the main read and write code.
