From: Dimitris Michailidis <dm@chelsio•com>
To: Ben Hutchings <bhutchings@solarflare•com>
Cc: Peter Waskiewicz <peter.p.waskiewicz.jr@intel•com>,
netdev@vger•kernel.org, David Miller <davem@davemloft•net>
Subject: Re: (Lack of) specification for RX n-tuple filtering
Date: Thu, 22 Jul 2010 14:50:18 -0700 [thread overview]
Message-ID: <4C48BD1A.4060409@chelsio.com> (raw)
In-Reply-To: <1279832544.2104.63.camel@achroite.uk.solarflarecom.com>
Ben Hutchings wrote:
> The n-tuple filtering facility is half-baked at present. There is an
> interface to add filters but none to remove them! And ETHTOOL_GRXNTUPLE
> is not at all symmetric with ETHTOOL_SRXNTUPLE (which I complained about
> at the time it was added, to no avail).
It's a bit worse than that. Currently one can only append filters, not
insert at a given position, as ethtool_rx_ntuple doesn't have an index
field. For devices that use TCAMs, where position matters, it's quite an
obstacle. It also means one cannot modify an existing filter by specifying
a new filter for the same index.
>
> An ETHTOOL_RESET command with flag ETH_RESET_FILTER set could be defined
> to clear all the filters, but that's a big hammer to use, and I think
> that in general drivers should push the same configuration back to the
> hardware after resetting it for whatever reason.
>
> So far as I can work out, ixgbe clears all the filters when the filter
> table fills up. Is that true? Is this really the intended behaviour of
> manually set filters?
>
> I also see this in the ixgbe implementation:
>
> /*
> * Program the relevant mask registers. If src/dst_port or src/dst_addr
> * are zero, then assume a full mask for that field. Also assume that
> * a VLAN of 0 is unspecified, so mask that out as well. L4type
> * cannot be masked out in this implementation.
> *
> * This also assumes IPv4 only. IPv6 masking isn't supported at this
> * point in time.
> */
>
> An IPv4 address of 0 is certainly valid, so this isn't a good rule. And
> in any case, such a rule should be specified *with the interface*, in
> <linux/ethtool.h>, not the implementation.
>
> This also implies that 'mask' specifies bits to be ignored, not bits to
> be matched. That also was not specified.
>
> Ben.`
>
next prev parent reply other threads:[~2010-07-22 21:50 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-22 21:02 (Lack of) specification for RX n-tuple filtering Ben Hutchings
2010-07-22 21:50 ` Dimitris Michailidis [this message]
2010-09-07 14:43 ` Ben Hutchings
2010-12-08 16:24 ` Vladislav Zolotarov
2010-12-08 16:39 ` David Miller
2010-12-08 17:29 ` Ben Hutchings
2010-12-08 17:31 ` David Miller
2010-12-09 10:31 ` Vladislav Zolotarov
2010-12-08 17:31 ` Vladislav Zolotarov
2010-12-08 17:22 ` Ben Hutchings
2010-12-08 18:39 ` Vladislav Zolotarov
2010-12-08 19:02 ` Ben Hutchings
2010-12-08 19:10 ` Vladislav Zolotarov
2010-12-08 19:14 ` Ben Hutchings
2010-12-08 19:39 ` Ben Hutchings
2010-12-08 18:54 ` Dimitris Michailidis
2010-12-08 19:14 ` Ben Hutchings
2010-12-08 19:26 ` Dimitris Michailidis
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