Since the protocol encodes timestamps differently depending on the
message, the code currently decodes into a local variable and then
converts it to a time.Time. However, this causes an allocation due to
the local having to escape to the heap in order for the readElement
function to write to it.
So, in order to avoid that, this introduces two new types for a
timestamp named uint32Time and int64Time that are encoded as the
respective type on the read. When calling the readElements function,
the time.Time field in the message is cast to a pointer of the
appropriate type which effectively allows the allocations to be avoided.
The following is a before and after comparison of the allocations
with the benchmarks that did not change removed:
benchmark old allocs new allocs delta
----------------------------------------------------------------------
ReadBlockHeader 1 0 -100.00%
DecodeHeaders 4001 2001 -49.99%
DecodeAddr 4001 3001 -24.99%
DecodeMerkleBlock 108 107 -0.93%
This implements the wire protocol encoding portion of a new
sendheaders message as described by BIP0130. It purpose is to request
that a peer sends header commands instead of inv commands when
announcing new blocks. This includes a protocol version bump to 70012
and a wire version bump to 0.4.0.
Note that this does not implement logic to handle the command in btcd,
rather it only makes the command available at the wire protocol level.
A future commit which honors the command and therefore provides full
BIP0130 support is still required.
This commit exports the ReadVarString and WriteVarString functions so
they are available for callers to use.
A variable length string is encoded as a variable length integer
containing the length of the string followed by the bytes that represent
the string itself.
SFNodeBloom is a new service flag that a node is required to use to
indicate that it supports bloom filtering. This includes a protocol
version bump to 70011 and a wire version bump to 0.3.0.
btcd:
The SFNodeBloom flag is set by default. A new configuration option
--nopeerbloomfilters has been added to to disable bloom filtering.
Any node advertising a version greater than or equal to 70011 that
attempts to use bloom filtering will be disconnected if bloom
filtering is disabled.
This mimics Bitcoin Core commit afb0ccaf9c9e4e8fac7db3564c4e19c9218c6b03
The Bitcoin wire protocol includes several fields with their lengths
encoded according to a variable length integer encoding scheme that does
not enforce a unique encoding for all numbers.
This can lead to a situation where deserializing and re-serializing the
same data can result in different bytes. There are no currently known
issues due to this, but it is safer to reject such subtle differences as
they could potentially lead to exploits.
Consequently, this commit modifies the varint decoding function to error
when the value is not canonically encoded which effectively means that
all messages with varints that are not canonically encoded will now be
rejected. This will not cause issues with old client versions in
regards to blocks and transactions since the data is deserialized into
memory and then reserialized before being relayed thereby effectively
erasing any non-canonical encodings.
Also, new tests have been added to ensure non-canonical encodings are
properly rejected and exercise the new code, and the default user agent
version for wire has been bumped to version 0.2.1 to differentiate the
new behavior.
The equivalent logic was implemented in Bitcoin Core by PR 2884.
This commit contains the entire btcwire repository along with several
changes needed to move all of the files into the wire directory in
order to prepare it for merging. This does NOT update btcd or any of the
other packages to use the new location as that will be done separately.
- All import paths in the old btcwire test files have been changed to the
new location
- All references to btcwire as the package name have been chagned to
wire
- The coveralls badge has been removed since it unfortunately doesn't
support coverage of sub-packages
This is ongoing work toward #214.
