Re: [PATCH]: setting bit-rate when injecting

[Johannes Berg <johannes@sipsolutions.net>]

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On Mon, 2009-11-09 at 17:07 +0100, Lorenzo Bianconi wrote:
> I and my Matteo Croce made a patch which adds the capability
> to set the bit-rate when injecting in monitor mode.
> 
> The code parse the bit-rate field from the radiotap header and passes the info
> to the struct ieee80211_tx_info
> 
> --- a/net/mac80211/tx.c	2009-11-09 16:41:15.000000000 +0100
> +++ b/net/mac80211/tx.c	2009-11-09 16:50:12.000000000 +0100
> @@ -505,6 +505,9 @@
>  	struct ieee80211_tx_rate_control txrc;
>  	u32 sta_flags;
> 
> +	if (info->control.vif->type == NL80211_IFTYPE_MONITOR)
> +		return TX_CONTINUE;

Sorry, can't do that, we need rate control for packets that are injected
from hostapd.

> -	int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
> +	int i, ret = ieee80211_radiotap_iterator_init(&iterator,
> +			rthdr, skb->len);
> +	struct ieee80211_rate *rates;

A separate "int i;" would be a lot cleaner I think.

>  	sband = tx->local->hw.wiphy->bands[tx->channel->band];
> 
> @@ -979,6 +984,25 @@
>  				tx->flags |= IEEE80211_TX_FRAGMENTED;
>  			break;
> 
> +		case IEEE80211_RADIOTAP_RATE:
> +			rates = sband->bitrates;
> +			for (i = 0; i < sband->n_bitrates; i++) {
> +				if (rates[i].bitrate/5 == *iterator.this_arg) {
> +					info->control.rates[0].idx = i;
> +					break;
> +				}
> +			}
> +			info->control.rates[0].flags = 0;

This leaves the number of retries at ... 0. That makes no sense. What
driver are you using that this actually works with?!

> @@ -1518,7 +1542,6 @@
>  					 struct net_device *dev)
>  {
>  	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
> -	struct ieee80211_channel *chan = local->hw.conf.channel;
>  	struct ieee80211_radiotap_header *prthdr =
>  		(struct ieee80211_radiotap_header *)skb->data;
>  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
> @@ -1540,9 +1563,6 @@
>  	 * radar detection by itself. We can do that later by adding a
>  	 * monitor flag interfaces used for AP support.
>  	 */
> -	if ((chan->flags & (IEEE80211_CHAN_NO_IBSS | IEEE80211_CHAN_RADAR |
> -	     IEEE80211_CHAN_PASSIVE_SCAN)))
> -		goto fail;

We don't want to break regulatory rules either ...

johannes

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