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Date: Tue, 22 Oct 2002 17:39:59 -0700
To: Linux kernel mailing list <linux-kernel@vger.kernel.org>,
       Slavcho Nikolov <snikolov@okena.com>
Cc: Jeff Garzik <jgarzik@mandrakesoft.com>
Subject: Re: feature request - why not make netif_rx() a pointer?
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From: Jean Tourrilhes <jt@bougret.hpl.hp.com>
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Slavcho Nikolov wrote :
> Non GPL modules that want to attach themselves between all L2 drivers and
> upper layers would not have to incur a performance loss if netif_rx() is
> made a
> pointer instead of a function (whether or not NET filters are compiled in
> the kernel).
> Currently control can be easily wrested from netif_rx() and others through
> injection of a few instructions into the running kernel (SMC - self
> modifying code)

	Assuming that every L2 is Ethernet and every L3 is IP ?
	Well, I've got news for you : IrDA drivers are using
netif_rx() to pass IrLAP frames to the IrDA stack, and 802.11 driver
in the future will pass 802.11 frames to the 802.2 LLC layer via
netif_rx().
	Please don't do that, I don't want people breaking the IrDA
stack in weird ways just because some random clueless code hijacked
netif_rx(). Use netfilters, or define your own private protocol/packet
type to do what you want.

	Regards,

	Jean

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