net/sched: cls_flower: Disallow duplicate internal elements

Flower currently allows having the same filter twice with the same
priority. Actions (and statistics update) will always execute on the
first inserted rule leaving the second rule unused.
This patch disallows that.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index a3bfda3091a48e5548f1ccd3cf9275ec4d391189..27934456d9840ee16d8e5f93e88a6ab82a5d823b 100644 (file)
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -134,6 +134,14 @@ static void fl_clear_masked_range(struct fl_flow_key *key,
        memset(fl_key_get_start(key, mask), 0, fl_mask_range(mask));
 }
 
+static struct cls_fl_filter *fl_lookup(struct cls_fl_head *head,
+                                      struct fl_flow_key *mkey)
+{
+       return rhashtable_lookup_fast(&head->ht,
+                                     fl_key_get_start(mkey, &head->mask),
+                                     head->ht_params);
+}
+
 static int fl_classify(struct sk_buff *skb, const struct tcf_proto *tp,
                       struct tcf_result *res)
 {
@@ -181,9 +189,7 @@ static int fl_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 
        fl_set_masked_key(&skb_mkey, &skb_key, &head->mask);
 
-       f = rhashtable_lookup_fast(&head->ht,
-                                  fl_key_get_start(&skb_mkey, &head->mask),
-                                  head->ht_params);
+       f = fl_lookup(head, &skb_mkey);
        if (f && !tc_skip_sw(f->flags)) {
                *res = f->res;
                return tcf_exts_exec(skb, &f->exts, res);
@@ -875,6 +881,11 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
                goto errout;
 
        if (!tc_skip_sw(fnew->flags)) {
+               if (!fold && fl_lookup(head, &fnew->mkey)) {
+                       err = -EEXIST;
+                       goto errout;
+               }
+
                err = rhashtable_insert_fast(&head->ht, &fnew->ht_node,
                                             head->ht_params);
                if (err)