mac80211: check if mesh frame is in RMC after decrypt

To check whether a frame is in the RMC, we need access to the mesh
header.  This header is encrypted in encrypted data frames, so make this
check after the frame has been decrypted.
Signed-off-by: NThomas Pedersen <thomas@cozybit.com>
Signed-off-by: NJavier Cardona <javier@cozybit.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

net/mac80211/rx.c

@@ -476,7 +476,6 @@ static ieee80211_rx_result
 ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
 {
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
-	unsigned int hdrlen = ieee80211_hdrlen(hdr->frame_control);
 	char *dev_addr = rx->sdata->vif.addr;
 
 	if (ieee80211_is_data(hdr->frame_control)) {
@@ -524,14 +523,6 @@ ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
 
 	}
 
-#define msh_h_get(h, l) ((struct ieee80211s_hdr *) ((u8 *)h + l))
-
-	if (ieee80211_is_data(hdr->frame_control) &&
-	    is_multicast_ether_addr(hdr->addr1) &&
-	    mesh_rmc_check(hdr->addr3, msh_h_get(hdr, hdrlen), rx->sdata))
-		return RX_DROP_MONITOR;
-#undef msh_h_get
-
 	return RX_CONTINUE;
 }
 
@@ -1840,6 +1831,12 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
 	mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 
+	/* frame is in RMC, don't forward */
+	if (ieee80211_is_data(hdr->frame_control) &&
+	    is_multicast_ether_addr(hdr->addr1) &&
+	    mesh_rmc_check(hdr->addr3, mesh_hdr, rx->sdata))
+		return RX_DROP_MONITOR;
+
 	if (!ieee80211_is_data(hdr->frame_control))
 		return RX_CONTINUE;