Re: [PATCH 2/4] mac80211: Add radiotap support for Monitor mode RX

From: Johannes Berg <johannes@sipsolutions.net>
To: andy@warmcat.com
Cc: linux-wireless@vger.kernel.org, Michael Wu <flamingice@sourmilk.net>
Subject: Re: [PATCH 2/4] mac80211: Add radiotap support for Monitor mode RX
Date: Wed, 21 Mar 2007 19:51:31 +0100	[thread overview]
Message-ID: <1174503091.3944.42.camel@johannes.berg> (raw)
In-Reply-To: <20070320104104.318699229@warmcat.com>

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> +	/* Driver supports radiotap. */
> +#define IEEE80211_HW_RADIOTAP_SUPPORTED (1<<10)

> +	if (local->monitors &&
> +	    local->hw.flags & IEEE80211_HW_RADIOTAP_SUPPORTED) {
> +		radiotap_len = ieee80211_get_radiotap_len(skb);
> +		skb_pull(skb, radiotap_len);
> +	}

I don't think that can work. 

 1) it needs a lot more documentation on what a driver needs to do for
    this (for example that it should only add radiotap headers if a
    monitor interface was added)

 2) afaik local->monitors is increased even for soft monitor interfaces,
    thus this will really fall on its nose when the driver supports
    radiotap but not monitor during operation.

johannes

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