Re: Find all matches with DPDK ACL

["Дмитрий Степанов" <stepanov.dmit@gmail.com>]

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Hi!
I have a big number of IPv4 5-tuple rules, every rule corresponds to some
action. I need to find all matched rules and perform all tied actions.
The search time greatly affects overall system performance, so I can't just
scan all rules. ACL is based on multi-bit tries and provides great
performance, so I'm looking for nearly the same performance with the
ability to find all matches within a single request.

ср, 24 нояб. 2021 г. в 18:20, Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>:

> 2021-11-24 11:06 (UTC+0100), Steffen Weise:
> > > Hi folks!
> > >
> > > I'm using DPDK's ACL library to classify incoming packets by IPv4 5
> tuple
> > > match (src address, dst address, src port, dst port, protocol). Right
> now
> > > it is possible to find only the best match based on the rule's
> priority.
> > > Is there any way (maybe a custom patch for the ACL library exists?) to
> > > find all matches in a single request? Decreased performance and even
> some
> > > false-positive matches are acceptable.
> > > It could be a big number of matches so using categories is not an
> option.
> > >
> > > Thanks,
> > > Dmitriy Stepanov
> > >
> >
> > Hi,
> >
> > I have the very same question. Such a mechanism would help me in my
> > applications. Currently I go for lookup on multiple separate tables.
> >
> > Cheers,
> > Steffen Weise
>
> Hi,
>
> I wonder what is the original problem you're solving.
>
> A set of IPv4 5-tuple rules can be viewed as a set of regular expressions:
>
> ACL:    src 1.1.1.0/24 dst 2.2.2.2/32 sport any dport 0x0035 proto tcp
> Regex:  ^\x01\x01\x01.\x02\x02\x02\x02..\x00\x35\x06$
>
> Here, "." stands for "any byte".
> For masks/ranges not aligned on 8 bits regex ranges can be used, e.g.:
>
> ACL:    sport 100-200
>         # this one is easy, just one byte varies
> Regex:  \x00[\x64-\xC8]
>
> ACL:    sport 200-300
>         # this one is hard, needs an algorithm to transform
>         # 200-300 => 200-255,256-300 => 0xC8-0xFF,0x0100-0x012C
> Regex:  (?:\x00[\xC8-xFF]|\x01[\x00-\x2C])
>
> ACL:    src 192.0.2.64/26
>         # this one is easy, there are also hard examples like above
> Regex:  \xC0\x00\x02[\x40-\x7F]
>
> IIUC, you need all matching expressions for every packet,
> which is represented as a 4+4+2+2+1 byte "string".
> This is exactly what Hyperscan library does, for example:
> http://intel.github.io/hyperscan/dev-reference/runtime.html
>
> There is now regexdev in DPDK,
> take a look at it, maybe it will suit your needs and HW.
>

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