mac80211: use common radiotap code for cooked monitors

There's no need to hardcode a subset of the
radiotap header for cooked monitor receive,
we can just reuse the normal monitor mode
radiotap code. This simplifies the code and
extends the information available on cooked
monitor interfaces.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/rx.c

@@ -228,7 +228,7 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 {
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
 	struct ieee80211_sub_if_data *sdata;
-	int needed_headroom = 0;
+	int needed_headroom;
 	struct sk_buff *skb, *skb2;
 	struct net_device *prev_dev = NULL;
 	int present_fcs_len = 0;
@@ -2544,16 +2544,10 @@ static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx,
 {
 	struct ieee80211_sub_if_data *sdata;
 	struct ieee80211_local *local = rx->local;
-	struct ieee80211_rtap_hdr {
-		struct ieee80211_radiotap_header hdr;
-		u8 flags;
-		u8 rate_or_pad;
-		__le16 chan_freq;
-		__le16 chan_flags;
-	} __packed *rthdr;
 	struct sk_buff *skb = rx->skb, *skb2;
 	struct net_device *prev_dev = NULL;
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
+	int needed_headroom;
 
 	/*
 	 * If cooked monitor has been processed already, then
@@ -2567,30 +2561,15 @@ static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx,
 	if (!local->cooked_mntrs)
 		goto out_free_skb;
 
-	if (skb_headroom(skb) < sizeof(*rthdr) &&
-	    pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC))
-		goto out_free_skb;
-
-	rthdr = (void *)skb_push(skb, sizeof(*rthdr));
-	memset(rthdr, 0, sizeof(*rthdr));
-	rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
-	rthdr->hdr.it_present =
-		cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
-			    (1 << IEEE80211_RADIOTAP_CHANNEL));
+	/* room for the radiotap header based on driver features */
+	needed_headroom = ieee80211_rx_radiotap_len(local, status);
 
-	if (rate) {
-		rthdr->rate_or_pad = rate->bitrate / 5;
-		rthdr->hdr.it_present |=
-			cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
-	}
-	rthdr->chan_freq = cpu_to_le16(status->freq);
+	if (skb_headroom(skb) < needed_headroom &&
+	    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC))
+		goto out_free_skb;
 
-	if (status->band == IEEE80211_BAND_5GHZ)
-		rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_OFDM |
-						IEEE80211_CHAN_5GHZ);
-	else
-		rthdr->chan_flags = cpu_to_le16(IEEE80211_CHAN_DYN |
-						IEEE80211_CHAN_2GHZ);
+	/* prepend radiotap information */
+	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom);
 
 	skb_set_mac_header(skb, 0);
 	skb->ip_summed = CHECKSUM_UNNECESSARY;