mirror of
https://github.com/bitcoin/bips.git
synced 2024-11-19 09:50:06 +01:00
86 lines
3.2 KiB
Plaintext
86 lines
3.2 KiB
Plaintext
<pre>
|
|
BIP: 111
|
|
Title: NODE_BLOOM service bit
|
|
Author: Matt Corallo <bip@bluematt.me>, Peter Todd <pete@petertodd.org>
|
|
Status: Draft
|
|
Type: Standards Track
|
|
Created: 2015-08-20
|
|
</pre>
|
|
|
|
== Abstract ==
|
|
|
|
This BIP extends BIP 37, Connection Bloom filtering, by defining a
|
|
service bit to allow peers to advertise that they support bloom filters
|
|
explicitly. It also bumps the protocol version to allow peers to
|
|
identify old nodes which allow bloom filtering of the connection despite
|
|
lacking the new service bit.
|
|
|
|
|
|
== Motivation ==
|
|
|
|
BIP 37 did not specify a service bit for the bloom filter service, thus
|
|
implicitly assuming that all nodes that serve peers data support it.
|
|
However, the connection filtering algorithm proposed in BIP 37, and
|
|
implemented in several clients today, has been shown to provide little
|
|
to no privacy<ref>http://eprint.iacr.org/2014/763</ref>, as well as being a large DoS risk on some nodes<ref>[http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2013-July/003044.html] is one example where the issues were found, though others independently discovered issues as well. Sample DoS exploit code available at https://github.com/petertodd/bloom-io-attack.</ref>.
|
|
Thus, allowing node operators to disable connection bloom filtering is a
|
|
much-needed feature.
|
|
|
|
|
|
== Specification ==
|
|
|
|
The following protocol bit is added:
|
|
|
|
<pre>
|
|
NODE_BLOOM = (1 << 2)
|
|
</pre>
|
|
|
|
Nodes which support bloom filters should set that protocol bit.
|
|
Otherwise it should remain unset. In addition the protocol version is
|
|
increased from 70002 to 70011 in the reference implementation. It is
|
|
often the case that nodes which have a protocol version smaller than
|
|
70011, but larger than 70000 support bloom filtered connections without
|
|
the NODE_BLOOM bit set, however clients which require bloom filtered
|
|
connections should avoid making this assumption.
|
|
|
|
NODE_BLOOM is distinct from NODE_NETWORK, and it is legal to advertise
|
|
NODE_BLOOM but not NODE_NETWORK (though there is little reason to do
|
|
so now, some proposals may make this more useful in the future)
|
|
|
|
If a node does not support bloom filters but receives a "filterload",
|
|
"filteradd", or "filterclear" message from a peer the node should
|
|
disconnect that peer immediately. For backwards compatibility, in
|
|
initial implementations, nodes may choose to only disconnect nodes which
|
|
have the new protocol version set and attempt to send a filter command.
|
|
|
|
While outside the scope of this BIP it is suggested that DNS seeds and
|
|
other peer discovery mechanisms support the ability to specify the
|
|
services required; current implementations simply check only that
|
|
NODE_NETWORK is set.
|
|
|
|
|
|
== Design rational ==
|
|
|
|
A service bit was chosen as applying a bloom filter is a service.
|
|
|
|
The increase in protocol version is for backwards compatibility. In
|
|
initial implementations, old nodes which are not yet aware of NODE_BLOOM
|
|
and use a protocol version < 70011 may still send filter messages to a
|
|
node without NODE_BLOOM. This feature may be removed after there are
|
|
sufficient NODE_BLOOM nodes available and SPV clients have upgraded,
|
|
allowing node operators to fully close the bloom-related DoS vectors.
|
|
|
|
|
|
== Reference Implementation ==
|
|
|
|
https://github.com/bitcoin/bitcoin/pull/6579
|
|
|
|
|
|
== Copyright ==
|
|
|
|
This document is placed in the public domain.
|
|
|
|
|
|
== References ==
|
|
<references>
|