Re: [PATCH] mac80211: Add radiotap support

[Johannes Berg <johannes@sipsolutions.net>]

[-- Attachment #1: Type: text/plain, Size: 1291 bytes --]

On Fri, 2007-04-06 at 00:48 -0400, Michael Wu wrote:

> @@ -3756,6 +3802,12 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
>  	struct ieee80211_txrx_data rx;
>  	u16 type;
>  	int multicast;
> +	int radiotap_len = 0;
> +
> +	if (status->flag & RX_FLAG_RADIOTAP) {
> +		radiotap_len = ieee80211_get_radiotap_len(skb);
> +		skb_pull(skb, radiotap_len);
> +	}
>  
>  	hdr = (struct ieee80211_hdr *) skb->data;
>  	memset(&rx, 0, sizeof(rx));
> @@ -3792,6 +3844,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
>  		goto end;
>  	skb = rx.skb;
>  
> +	skb_push(skb, radiotap_len);

I don't like this trick. It's so non-obvious. And inbetween, the only
thing we ever use is skb->data (once, to get hdr assigned) and skb->len
(which we could also load into a local variable.

> @@ -3800,7 +3853,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
>  	} else {
>  		struct ieee80211_sub_if_data *prev = NULL;
>  		struct sk_buff *skb_new;
> -		u8 *bssid = ieee80211_get_bssid(hdr, skb->len);
> +		u8 *bssid = ieee80211_get_bssid(hdr, skb->len - radiotap_len);

and here you still need to do the subtraction. If you had the local
variable, then you could just write frame_len or something.

johannes

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 190 bytes --]