mac80211: move ieee80211_get_bssid into RX file

This function is only used in the RX code, so moving it into
that file gives the compiler better optimisation possibilities
and also allows us to remove the check for short frames (which
in the RX path cannot happen, but as a generic utility needed
to be checked.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index aa57a2ab8245..dd6bb2a54d45 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -42,6 +42,51 @@ static inline void ieee80211_rx_stats(struct net_device *dev, u32 len)
 	u64_stats_update_end(&tstats->syncp);
 }
 
+static u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
+			       enum nl80211_iftype type)
+{
+	__le16 fc = hdr->frame_control;
+
+	if (ieee80211_is_data(fc)) {
+		if (len < 24) /* drop incorrect hdr len (data) */
+			return NULL;
+
+		if (ieee80211_has_a4(fc))
+			return NULL;
+		if (ieee80211_has_tods(fc))
+			return hdr->addr1;
+		if (ieee80211_has_fromds(fc))
+			return hdr->addr2;
+
+		return hdr->addr3;
+	}
+
+	if (ieee80211_is_mgmt(fc)) {
+		if (len < 24) /* drop incorrect hdr len (mgmt) */
+			return NULL;
+		return hdr->addr3;
+	}
+
+	if (ieee80211_is_ctl(fc)) {
+		if (ieee80211_is_pspoll(fc))
+			return hdr->addr1;
+
+		if (ieee80211_is_back_req(fc)) {
+			switch (type) {
+			case NL80211_IFTYPE_STATION:
+				return hdr->addr2;
+			case NL80211_IFTYPE_AP:
+			case NL80211_IFTYPE_AP_VLAN:
+				return hdr->addr1;
+			default:
+				break; /* fall through to the return */
+			}
+		}
+	}
+
+	return NULL;
+}
+
 /*
  * monitor mode reception
  *