neigh: Convert over to dst_neigh_lookup_skb().

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 3 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index a793af9af150..117afaf51268 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1201,10 +1201,23 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
                         write_unlock_bh(&neigh->lock);
 
                         rcu_read_lock();
-                        /* On shaper/eql skb->dst->neighbour != neigh :( */
-                        if (dst && (n2 = dst_get_neighbour_noref(dst)) != NULL)
-                                n1 = n2;
+
+                        /* Why not just use 'neigh' as-is?  The problem is that
+                         * things such as shaper, eql, and sch_teql can end up
+                         * using alternative, different, neigh objects to output
+                         * the packet in the output path.  So what we need to do
+                         * here is re-lookup the top-level neigh in the path so
+                         * we can reinject the packet there.
+                         */
+                        n2 = NULL;
+                        if (dst) {
+                                n2 = dst_neigh_lookup_skb(dst, skb);
+                                if (n2)
+                                        n1 = n2;
+                        }
                         n1->output(n1, skb);
+                        if (n2)
+                                neigh_release(n2);
                         rcu_read_unlock();
 
                         write_lock_bh(&neigh->lock);