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- Update all Accepted status to Proposed (renamed status) - The BIP Comments preamble headers added to every BIP - The License preamble headers have been added to all BIPs with a Copyright section
91 lines
3.4 KiB
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91 lines
3.4 KiB
Plaintext
<pre>
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BIP: 111
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Layer: Peer Services
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Title: NODE_BLOOM service bit
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Author: Matt Corallo <bip111@bluematt.me>
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Peter Todd <pete@petertodd.org>
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Comments-Summary: No comments yet.
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Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0111
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Status: Proposed
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Type: Standards Track
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Created: 2015-08-20
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License: PD
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</pre>
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== Abstract ==
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This BIP extends BIP 37, Connection Bloom filtering, by defining a
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service bit to allow peers to advertise that they support bloom filters
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explicitly. It also bumps the protocol version to allow peers to
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identify old nodes which allow bloom filtering of the connection despite
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lacking the new service bit.
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== Motivation ==
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BIP 37 did not specify a service bit for the bloom filter service, thus
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implicitly assuming that all nodes that serve peers data support it.
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However, the connection filtering algorithm proposed in BIP 37, and
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implemented in several clients today, has been shown to provide little
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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>.
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Thus, allowing node operators to disable connection bloom filtering is a
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much-needed feature.
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== Specification ==
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The following protocol bit is added:
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<pre>
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NODE_BLOOM = (1 << 2)
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</pre>
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Nodes which support bloom filters should set that protocol bit.
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Otherwise it should remain unset. In addition the protocol version is
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increased from 70002 to 70011 in the reference implementation. It is
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often the case that nodes which have a protocol version smaller than
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70011, but larger than 70000 support bloom filtered connections without
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the NODE_BLOOM bit set, however clients which require bloom filtered
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connections should avoid making this assumption.
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NODE_BLOOM is distinct from NODE_NETWORK, and it is legal to advertise
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NODE_BLOOM but not NODE_NETWORK (though there is little reason to do
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so now, some proposals may make this more useful in the future)
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If a node does not support bloom filters but receives a "filterload",
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"filteradd", or "filterclear" message from a peer the node should
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disconnect that peer immediately. For backwards compatibility, in
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initial implementations, nodes may choose to only disconnect nodes which
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have the new protocol version set and attempt to send a filter command.
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While outside the scope of this BIP it is suggested that DNS seeds and
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other peer discovery mechanisms support the ability to specify the
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services required; current implementations simply check only that
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NODE_NETWORK is set.
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== Design rational ==
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A service bit was chosen as applying a bloom filter is a service.
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The increase in protocol version is for backwards compatibility. In
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initial implementations, old nodes which are not yet aware of NODE_BLOOM
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and use a protocol version < 70011 may still send filter messages to a
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node without NODE_BLOOM. This feature may be removed after there are
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sufficient NODE_BLOOM nodes available and SPV clients have upgraded,
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allowing node operators to fully close the bloom-related DoS vectors.
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== Reference Implementation ==
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https://github.com/bitcoin/bitcoin/pull/6579
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== Copyright ==
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This document is placed in the public domain.
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== References ==
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<references>
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