linux-kernel - Re: [PATCH 2/3] x_tables: Use also dev->ifalias for interface matching

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Date:	Mon, 12 Jan 2015 08:46:08 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Jan Engelhardt <jengelh@...i.de>
Cc:	Richard Weinberger <richard@....at>, davem@...emloft.net,
	coreteam@...filter.org, netfilter-devel@...r.kernel.org,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	bhutchings@...arflare.com, john.fastabend@...il.com,
	herbert@...dor.apana.org.au, vyasevic@...hat.com, jiri@...nulli.us,
	vfalico@...il.com, therbert@...gle.com, edumazet@...gle.com,
	yoshfuji@...ux-ipv6.org, jmorris@...ei.org, kuznet@....inr.ac.ru,
	kadlec@...ckhole.kfki.hu, kaber@...sh.net, pablo@...filter.org,
	kay@...y.org, stephen@...workplumber.org
Subject: Re: [PATCH 2/3] x_tables: Use also dev->ifalias for interface
 matching

On Mon, 2015-01-12 at 17:32 +0100, Jan Engelhardt wrote:
> On Monday 2015-01-12 17:04, Eric Dumazet wrote:
> >
> >iptables should have used ifindex [for interface matching],
> >it[']s sad we allowed the substring match in first place.
> 
> How would you solve interface name wildcards with ifindices?
> (They come in handy if you have something like lots of tun+/veth+
> interfaces from openvpn/lxc.)


This is what I said : "it[']s sad we allowed the substring match in
first place."

This obviously referred to wildcards, in the in/out interface match for
every _single_ rule, consuming 64 bytes of memory per rule and per cpu !
Which is absolutely crazy in term of memory usage.

Matching tun+ or whatever could easily be done by a match (-m ...),
because you can factorize this quite easily (called once for a group of
rules)



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