[PATCH 01/18] net/sched: cls_flower: Disallow duplicate internal elements

[Talat Batheesh]

From: Paul Blakey <paulb at mellanox.com>

BugLink: https://bugs.launchpad.net/ubuntu/1668019

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 at mellanox.com>
Acked-by: Jiri Pirko <jiri at mellanox.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit a3308d8fd1f58c67aaae52d9468791c2082ab2c7)
Signed-off-by: Talat Batheesh <talatb at mellanox.com>
---
 net/sched/cls_flower.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 5752789..a9a3790 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -133,6 +133,14 @@ 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)
 {
@@ -180,9 +188,7 @@ 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);
@@ -845,6 +851,11 @@ 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)
-- 
2.5.0