[net PATCH v2 2/6] net sched: ipt action fix late binding

[Jamal Hadi Salim]

From: Jamal Hadi Salim <j...@mojatatu.com>

This was broken and is fixed with this patch.

//add an ipt action and give it an instance id of 1
sudo tc actions add action ipt -j mark --set-mark 2 index 1
//create a filter which binds to ipt 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 ipt index 1

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

Signed-off-by: Jamal Hadi Salim <j...@mojatatu.com>
---
 net/sched/act_ipt.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 350e134..8b52700 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -96,7 +96,7 @@ static int __tcf_ipt_init(struct tc_action_net *tn, struct 
nlattr *nla,
        struct tcf_ipt *ipt;
        struct xt_entry_target *td, *t;
        char *tname;
-       int ret = 0, err;
+       int ret = 0, err, exists = 0;
        u32 hook = 0;
        u32 index = 0;
 
@@ -107,18 +107,23 @@ static int __tcf_ipt_init(struct tc_action_net *tn, 
struct nlattr *nla,
        if (err < 0)
                return err;
 
-       if (tb[TCA_IPT_HOOK] == NULL)
-               return -EINVAL;
-       if (tb[TCA_IPT_TARG] == NULL)
+       if (tb[TCA_IPT_INDEX] != NULL)
+               index = nla_get_u32(tb[TCA_IPT_INDEX]);
+
+       exists = tcf_hash_check(tn, index, a, bind);
+       if (exists && bind)
+               return 0;
+
+       if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
+               if (exists)
+                       tcf_hash_release(a, bind);
                return -EINVAL;
+       }
 
        td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
        if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
                return -EINVAL;
 
-       if (tb[TCA_IPT_INDEX] != NULL)
-               index = nla_get_u32(tb[TCA_IPT_INDEX]);
-
        if (!tcf_hash_check(tn, index, a, bind)) {
                ret = tcf_hash_create(tn, index, est, a, sizeof(*ipt), bind,
                                      false);
-- 
1.9.1