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Netfilter updates for net-next
This batch contains Netfilter updates for net-next:
1) Add nft_setelem_parse_key() helper function.
2) Add NFTA_SET_ELEM_KEY_END to specify a range with one single element.
3) Add NFTA_SET_DESC_CONCAT to describe the set element concatenation,
from Stefano Brivio.
4) Add bitmap_cut() to copy n-bits from source to destination,
from Stefano Brivio.
5) Add set to match on arbitrary concatenations, from Stefano Brivio.
6) Add selftest for this new set type. An extract of Stefano's
description follows:
"Existing nftables set implementations allow matching entries with
interval expressions (rbtree), e.g. 192.0.2.1-192.0.2.4, entries
specifying field concatenation (hash, rhash), e.g. 192.0.2.1:22,
but not both.
In other words, none of the set types allows matching on range
expressions for more than one packet field at a time, such as ipset
does with types bitmap:ip,mac, and, to a more limited extent
(netmasks, not arbitrary ranges), with types hash:net,net,
hash:net,port, hash:ip,port,net, and hash:net,port,net.
As a pure hash-based approach is unsuitable for matching on ranges,
and "proxying" the existing red-black tree type looks impractical as
elements would need to be shared and managed across all employed
trees, this new set implementation intends to fill the functionality
gap by employing a relatively novel approach.
The fundamental idea, illustrated in deeper detail in patch 5/9, is to
use lookup tables classifying a small number of grouped bits from each
field, and map the lookup results in a way that yields a verdict for
the full set of specified fields.
The grouping bit aspect is loosely inspired by the Grouper algorithm,
by Jay Ligatti, Josh Kuhn, and Chris Gage (see patch 5/9 for the full
reference).
A reference, stand-alone implementation of the algorithm itself is
available at:
https://pipapo.lameexcu.se
Some notes about possible future optimisations are also mentioned
there. This algorithm reduces the matching problem to, essentially,
a repetitive sequence of simple bitwise operations, and is
particularly suitable to be optimised by leveraging SIMD instruction
sets."
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Signed-off-by: David S. Miller <davem@davemloft.net>
projects / kernel.git / commit