net sched: skbedit action fix late binding

The process below was broken and is fixed with this patch.

//add a skbedit action and give it an instance id of 1
sudo tc actions add action skbedit mark 10 index 1
//create a filter which binds to skbedit action id 1
sudo tc filter add dev $DEV parent ffff: protocol ip prio 1 u32\
match ip dst 17.0.0.1/32 flowid 1:10 action skbedit index 1

Message before fix was:
RTNETLINK answers: Invalid argument
We have an error talking to the kernel

Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 7 deletions

diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index cfcdbdc00c9b..69da5a8f0034 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -69,7 +69,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
         struct tcf_skbedit *d;
         u32 flags = 0, *priority = NULL, *mark = NULL;
         u16 *queue_mapping = NULL;
-        int ret = 0, err;
+        int ret = 0, err, exists = 0;
 
         if (nla == NULL)
                 return -EINVAL;
@@ -96,12 +96,18 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
                 mark = nla_data(tb[TCA_SKBEDIT_MARK]);
         }
 
-        if (!flags)
-                return -EINVAL;
-
         parm = nla_data(tb[TCA_SKBEDIT_PARMS]);
 
-        if (!tcf_hash_check(tn, parm->index, a, bind)) {
+        exists = tcf_hash_check(tn, parm->index, a, bind);
+        if (exists && bind)
+                return 0;
+
+        if (!flags) {
+                tcf_hash_release(a, bind);
+                return -EINVAL;
+        }
+
+        if (!exists) {
                 ret = tcf_hash_create(tn, parm->index, est, a,
                                       sizeof(*d), bind, false);
                 if (ret)
@@ -111,8 +117,6 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
                 ret = ACT_P_CREATED;
         } else {
                 d = to_skbedit(a);
-                if (bind)
-                        return 0;
                 tcf_hash_release(a, bind);
                 if (!ovr)
                         return -EEXIST;