mac80211: remove RX_FLAG_RADIOTAP

While there may be a case for a driver adding its
own bits of radiotap information, none currently
does. Also, drivers would have to copy the code
to generate the radiotap bits that now mac80211
generates. If some driver in the future needs to
add some driver-specific information I'd expect
that to be in a radiotap vendor namespace and we
can add a different way of passing such data up
and having mac80211 include it.

Additionally, rename IEEE80211_CONF_RADIOTAP to
IEEE80211_CONF_MONITOR since it's still used by
b43(legacy) to obtain per-frame timestamps.

The purpose of this patch is to simplify the RX
code in mac80211 to make it easier to add paged
skb support.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 16 insertions, 25 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 14f10eb..8495161 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -214,8 +214,8 @@ static int ieee80211_open(struct net_device *dev)
 		/* must be before the call to ieee80211_configure_filter */
 		local->monitors++;
 		if (local->monitors == 1) {
-			local->hw.conf.flags |= IEEE80211_CONF_RADIOTAP;
-			hw_reconf_flags |= IEEE80211_CONF_CHANGE_RADIOTAP;
+			local->hw.conf.flags |= IEEE80211_CONF_MONITOR;
+			hw_reconf_flags |= IEEE80211_CONF_CHANGE_MONITOR;
 		}
 
 		if (sdata->u.mntr_flags & MONITOR_FLAG_FCSFAIL)
@@ -435,8 +435,8 @@ static int ieee80211_stop(struct net_device *dev)
 
 		local->monitors--;
 		if (local->monitors == 0) {
-			local->hw.conf.flags &= ~IEEE80211_CONF_RADIOTAP;
-			hw_reconf_flags |= IEEE80211_CONF_CHANGE_RADIOTAP;
+			local->hw.conf.flags &= ~IEEE80211_CONF_MONITOR;
+			hw_reconf_flags |= IEEE80211_CONF_CHANGE_MONITOR;
 		}
 
 		if (sdata->u.mntr_flags & MONITOR_FLAG_FCSFAIL)
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 01df328..798fa82 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -39,11 +39,8 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
  * only useful for monitoring.
  */
 static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
-					   struct sk_buff *skb,
-					   int rtap_len)
+					   struct sk_buff *skb)
 {
-	skb_pull(skb, rtap_len);
-
 	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
 		if (likely(skb->len > FCS_LEN))
 			skb_trim(skb, skb->len - FCS_LEN);
@@ -59,15 +56,14 @@ static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
 }
 
 static inline int should_drop_frame(struct sk_buff *skb,
-				    int present_fcs_len,
-				    int radiotap_len)
+				    int present_fcs_len)
 {
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 
 	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
 		return 1;
-	if (unlikely(skb->len < 16 + present_fcs_len + radiotap_len))
+	if (unlikely(skb->len < 16 + present_fcs_len))
 		return 1;
 	if (ieee80211_is_ctl(hdr->frame_control) &&
 	    !ieee80211_is_pspoll(hdr->frame_control) &&
@@ -225,7 +221,6 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 	struct sk_buff *skb, *skb2;
 	struct net_device *prev_dev = NULL;
 	int present_fcs_len = 0;
-	int rtap_len = 0;
 
 	/*
 	 * First, we may need to make a copy of the skb because
@@ -235,25 +230,23 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 	 * We don't need to, of course, if we aren't going to return
 	 * the SKB because it has a bad FCS/PLCP checksum.
 	 */
-	if (status->flag & RX_FLAG_RADIOTAP)
-		rtap_len = ieee80211_get_radiotap_len(origskb->data);
-	else
-		/* room for the radiotap header based on driver features */
-		needed_headroom = ieee80211_rx_radiotap_len(local, status);
+
+	/* room for the radiotap header based on driver features */
+	needed_headroom = ieee80211_rx_radiotap_len(local, status);
 
 	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
 		present_fcs_len = FCS_LEN;
 
 	if (!local->monitors) {
-		if (should_drop_frame(origskb, present_fcs_len, rtap_len)) {
+		if (should_drop_frame(origskb, present_fcs_len)) {
 			dev_kfree_skb(origskb);
 			return NULL;
 		}
 
-		return remove_monitor_info(local, origskb, rtap_len);
+		return remove_monitor_info(local, origskb);
 	}
 
-	if (should_drop_frame(origskb, present_fcs_len, rtap_len)) {
+	if (should_drop_frame(origskb, present_fcs_len)) {
 		/* only need to expand headroom if necessary */
 		skb = origskb;
 		origskb = NULL;
@@ -277,16 +270,14 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 		 */
 		skb = skb_copy_expand(origskb, needed_headroom, 0, GFP_ATOMIC);
 
-		origskb = remove_monitor_info(local, origskb, rtap_len);
+		origskb = remove_monitor_info(local, origskb);
 
 		if (!skb)
 			return origskb;
 	}
 
-	/* if necessary, prepend radiotap information */
-	if (!(status->flag & RX_FLAG_RADIOTAP))
-		ieee80211_add_rx_radiotap_header(local, skb, rate,
-						 needed_headroom);
+	/* prepend radiotap information */
+	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom);
 
 	skb_reset_mac_header(skb);
 	skb->ip_summed = CHECKSUM_UNNECESSARY;