Re: [PATCH] af_unix: implement socket filter

Le Tue, 18 Jan 2011 18:22:41 +0100,
Eric Dumazet [off-list ref] a écrit :

Le mardi 18 janvier 2011 à 16:39 +0000, Ian Molton a écrit :

quoted

From: Alban Crequy <redacted>

Linux Socket Filters can already be successfully attached and
detached on unix sockets with setsockopt(sockfd, SOL_SOCKET,
SO_{ATTACH,DETACH}_FILTER, ....). See:
Documentation/networking/filter.txt

But the filter was never used in the unix socket code so it did not
work. This patch uses sk_filter() to filter buffers before delivery.

This short program demonstrates the problem on SOCK_DGRAM.

By the way, the patch implements socket filters on SOCK_DGRAM and
SOCK_SEQPACKET but not SOCK_STREAM. Socket filters does not make sense
to me when there is no packet boundaries. But if there is a need for
it, the code for SOCK_STREAM could be added easily.

Any idea on performance cost adding sk_filter() call ?

Ian will write a performance test and repost the patch with some stats.
I don't know about the performance cost.

Hmm, looking at it, I have no idea why sk_filter() needs to block BH.

I don't know neither.

I'll send a patch to relax this requirement.

Thanks for your review!

Alban