mac80211: fix miscounting of ttl-dropped frames

In ieee80211_rx_h_mesh_fwding, we increment the 'dropped_frames_ttl'
counter when we decrement the ttl to zero.  For unicast frames
destined for other hosts, we stop processing the frame at that point.

For multicast frames, we do not rebroadcast it in this case, but we
do pass the frame up the stack to process it on this STA.  That
doesn't match the usual definition of "dropped," so don't count
those as such.

With this change, something like `ping6 -i0.2 ff02::1%mesh0` from a
peer in a ttl=1 network no longer increments the counter rapidly.

Signed-off-by: Bob Copeland <bobcopeland@fb.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 45aad3d3108cccce9626c2682ae390a8b0991568..27a337bc8acfd1af9385c4cee5149b939d331278 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2723,7 +2723,9 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
        skb_set_queue_mapping(skb, q);
 
        if (!--mesh_hdr->ttl) {
-               IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_ttl);
+               if (!is_multicast_ether_addr(hdr->addr1))
+                       IEEE80211_IFSTA_MESH_CTR_INC(ifmsh,
+                                                    dropped_frames_ttl);
                goto out;
        }