[PATCH net] net/sched: cls_flower: Reject duplicated rules also under skip_sw

[Or Gerlitz]

Currently, duplicated rules are rejected only for skip_hw or "none",
hence allowing users to push duplicates into HW for no reason.

Use the flower tables to protect for that.

Signed-off-by: Or Gerlitz <ogerl...@mellanox.com>
Signed-off-by: Paul Blakey <pa...@mellanox.com>
Reported-by: Chris Mi <chr...@mellanox.com>
---
changes from RFC:
 - properly handle delete as well

 net/sched/cls_flower.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index c6c327874abc..71312d7bd8f4 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -1238,18 +1238,16 @@ static int fl_change(struct net *net, struct sk_buff 
*in_skb,
        if (err)
                goto errout_idr;
 
-       if (!tc_skip_sw(fnew->flags)) {
-               if (!fold && fl_lookup(fnew->mask, &fnew->mkey)) {
-                       err = -EEXIST;
-                       goto errout_mask;
-               }
-
-               err = rhashtable_insert_fast(&fnew->mask->ht, &fnew->ht_node,
-                                            fnew->mask->filter_ht_params);
-               if (err)
-                       goto errout_mask;
+       if (!fold && fl_lookup(fnew->mask, &fnew->mkey)) {
+               err = -EEXIST;
+               goto errout_mask;
        }
 
+       err = rhashtable_insert_fast(&fnew->mask->ht, &fnew->ht_node,
+                                    fnew->mask->filter_ht_params);
+       if (err)
+               goto errout_mask;
+
        if (!tc_skip_hw(fnew->flags)) {
                err = fl_hw_replace_filter(tp, fnew, extack);
                if (err)
@@ -1303,9 +1301,8 @@ static int fl_delete(struct tcf_proto *tp, void *arg, 
bool *last,
        struct cls_fl_head *head = rtnl_dereference(tp->root);
        struct cls_fl_filter *f = arg;
 
-       if (!tc_skip_sw(f->flags))
-               rhashtable_remove_fast(&f->mask->ht, &f->ht_node,
-                                      f->mask->filter_ht_params);
+       rhashtable_remove_fast(&f->mask->ht, &f->ht_node,
+                              f->mask->filter_ht_params);
        __fl_delete(tp, f, extack);
        *last = list_empty(&head->masks);
        return 0;
-- 
2.17.0.2884.g4ede3d4