net sched: mirred action fix late binding

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

//add an mirred action and give it an instance id of 1
sudo tc actions add action mirred egress mirror dev $MDEV  index 1
//create a filter which binds to mirred 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 mirred 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 <jhs@mojatatu.com>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index e8a760cf7775ea1e3c9522376c3e3111a54a2ba6..8f3948dd38b85f70e654e317280db09e66c23f5c 100644 (file)
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -61,7 +61,7 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
        struct tc_mirred *parm;
        struct tcf_mirred *m;
        struct net_device *dev;
-       int ret, ok_push = 0;
+       int ret, ok_push = 0, exists = 0;
 
        if (nla == NULL)
                return -EINVAL;
@@ -71,17 +71,27 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
        if (tb[TCA_MIRRED_PARMS] == NULL)
                return -EINVAL;
        parm = nla_data(tb[TCA_MIRRED_PARMS]);
+
+       exists = tcf_hash_check(tn, parm->index, a, bind);
+       if (exists && bind)
+               return 0;
+
        switch (parm->eaction) {
        case TCA_EGRESS_MIRROR:
        case TCA_EGRESS_REDIR:
                break;
        default:
+               if (exists)
+                       tcf_hash_release(a, bind);
                return -EINVAL;
        }
        if (parm->ifindex) {
                dev = __dev_get_by_index(net, parm->ifindex);
-               if (dev == NULL)
+               if (dev == NULL) {
+                       if (exists)
+                               tcf_hash_release(a, bind);
                        return -ENODEV;
+               }
                switch (dev->type) {
                case ARPHRD_TUNNEL:
                case ARPHRD_TUNNEL6:
@@ -99,7 +109,7 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
                dev = NULL;
        }
 
-       if (!tcf_hash_check(tn, parm->index, a, bind)) {
+       if (!exists) {
                if (dev == NULL)
                        return -EINVAL;
                ret = tcf_hash_create(tn, parm->index, est, a,
@@ -108,9 +118,6 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
                        return ret;
                ret = ACT_P_CREATED;
        } else {
-               if (bind)
-                       return 0;
-
                tcf_hash_release(a, bind);
                if (!ovr)
                        return -EEXIST;