Subject: Re: [RFC] mac80211: clean up frame receive handling
From: Johannes Berg <johannes@sipsolutions.net>
To: "John W. Linville" <linville@tuxdriver.com>
Cc: linux-wireless <linux-wireless@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	Michael Wu <flamingice@sourmilk.net>,
	Tomas Winkler <tomasw@gmail.com>, Jouni Malinen <j@w1.fi>
In-Reply-To: <20071213204933.GD3083@tuxdriver.com>
References: <1197483844.6558.158.camel@johannes.berg>
	 <20071213204933.GD3083@tuxdriver.com>
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Date: Fri, 14 Dec 2007 13:14:03 +0100
Message-Id: <1197634443.16079.36.camel@johannes.berg> (sfid-20071214_121758_220639_6ED59E94)
Mime-Version: 1.0
Sender: linux-wireless-owner@vger.kernel.org


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> > +static bool ieee80211_frame_allowed(struct ieee80211_txrx_data *rx)
> > +{
> > +	static const u8 pae_group_addr[ETH_ALEN]
> > +		=3D { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x03 };
> > +	struct ethhdr *ehdr =3D (struct ethhdr *)rx->skb->data;
> > +
> > +	if (rx->skb->protocol =3D=3D htons(ETH_P_PAE) &&
> > +	    (compare_ether_addr(ehdr->h_dest, pae_group_addr) =3D=3D 0 ||
> > +	     compare_ether_addr(ehdr->h_dest, rx->dev->dev_addr) =3D=3D 0))
> > +		return true;
>=20
> Should you reverse these two compare_ether_addr calls?
> rx->dev->dev_addr seems more likely for any given packet.  It probably
> makes little difference but it seems like checking for that first
> would still be better.

I think in theory all eapol frames are sent to the PAE group address,
but I have no idea which of the checks would be more efficient. It seems
that the first could be optimised a lot because it's constant too...

johannes

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