net/sched: act_vlan: Introduce TCA_VLAN_ACT_MODIFY vlan action

TCA_VLAN_ACT_MODIFY allows one to change an existing tag.

It accepts same attributes as TCA_VLAN_ACT_PUSH (protocol, id,
priority).
If packet is vlan tagged, then the tag gets overwritten according to
user specified attributes.

For example, this allows user to replace a tag's vid while preserving
its priority bits (as opposed to "action vlan pop pipe action vlan push").

Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/tc_act/tc_vlan.h b/include/uapi/linux/tc_act/tc_vlan.h
index be72b6e..bddb272 100644 (file)
--- a/include/uapi/linux/tc_act/tc_vlan.h
+++ b/include/uapi/linux/tc_act/tc_vlan.h
@@ -16,6 +16,7 @@
 
 #define TCA_VLAN_ACT_POP       1
 #define TCA_VLAN_ACT_PUSH      2
+#define TCA_VLAN_ACT_MODIFY    3
 
 struct tc_vlan {
        tc_gen;

diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index 59a8d31..a95c00b 100644 (file)
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -30,6 +30,7 @@ static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
        struct tcf_vlan *v = to_vlan(a);
        int action;
        int err;
+       u16 tci;
 
        spin_lock(&v->tcf_lock);
        tcf_lastuse_update(&v->tcf_tm);
@@ -48,6 +49,30 @@ static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
                if (err)
                        goto drop;
                break;
+       case TCA_VLAN_ACT_MODIFY:
+               /* No-op if no vlan tag (either hw-accel or in-payload) */
+               if (!skb_vlan_tagged(skb))
+                       goto unlock;
+               /* extract existing tag (and guarantee no hw-accel tag) */
+               if (skb_vlan_tag_present(skb)) {
+                       tci = skb_vlan_tag_get(skb);
+                       skb->vlan_tci = 0;
+               } else {
+                       /* in-payload vlan tag, pop it */
+                       err = __skb_vlan_pop(skb, &tci);
+                       if (err)
+                               goto drop;
+               }
+               /* replace the vid */
+               tci = (tci & ~VLAN_VID_MASK) | v->tcfv_push_vid;
+               /* replace prio bits, if tcfv_push_prio specified */
+               if (v->tcfv_push_prio) {
+                       tci &= ~VLAN_PRIO_MASK;
+                       tci |= v->tcfv_push_prio << VLAN_PRIO_SHIFT;
+               }
+               /* put updated tci as hwaccel tag */
+               __vlan_hwaccel_put_tag(skb, v->tcfv_push_proto, tci);
+               break;
        default:
                BUG();
        }
@@ -102,6 +127,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
        case TCA_VLAN_ACT_POP:
                break;
        case TCA_VLAN_ACT_PUSH:
+       case TCA_VLAN_ACT_MODIFY:
                if (!tb[TCA_VLAN_PUSH_VLAN_ID]) {
                        if (exists)
                                tcf_hash_release(*a, bind);
@@ -185,7 +211,8 @@ static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,
        if (nla_put(skb, TCA_VLAN_PARMS, sizeof(opt), &opt))
                goto nla_put_failure;
 
-       if (v->tcfv_action == TCA_VLAN_ACT_PUSH &&
+       if ((v->tcfv_action == TCA_VLAN_ACT_PUSH ||
+            v->tcfv_action == TCA_VLAN_ACT_MODIFY) &&
            (nla_put_u16(skb, TCA_VLAN_PUSH_VLAN_ID, v->tcfv_push_vid) ||
             nla_put_be16(skb, TCA_VLAN_PUSH_VLAN_PROTOCOL,
                          v->tcfv_push_proto) ||