net/sched: cls_flower: Introduce support in SKIP SW flag

In order to make a filter processed only by hardware, skip_sw flag
should be supplied. This is an addition to the already existing skip_hw
flag (filter will be processed by software only). If no flag is
specified, filter will be processed by both software and hardware.

If only hardware offloaded filters exist, fl_classify() will return
without doing anything.

A following userspace patch will be sent once kernel patch is accepted.

Example:

tc filter add dev enp0s9 protocol ip prio 20 parent ffff: \
	flower \
		ip_proto 6 \
		indev enp0s9 \
		skip_sw \
	action skbedit mark 0x1234

Signed-off-by: Amir Vadai <amirva@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 730aaca..d737492 100644 (file)
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -66,6 +66,7 @@ struct cls_fl_filter {
        struct fl_flow_key key;
        struct list_head list;
        u32 handle;
+       u32 flags;
        struct rcu_head rcu;
 };
 
@@ -123,6 +124,9 @@ static int fl_classify(struct sk_buff *skb, const struct tcf_proto *tp,
        struct fl_flow_key skb_key;
        struct fl_flow_key skb_mkey;
 
+       if (!atomic_read(&head->ht.nelems))
+               return -1;
+
        fl_clear_masked_range(&skb_key, &head->mask);
        skb_key.indev_ifindex = skb->skb_iif;
        /* skb_flow_dissect() does not set n_proto in case an unknown protocol,
@@ -136,7 +140,7 @@ static int fl_classify(struct sk_buff *skb, const struct tcf_proto *tp,
        f = rhashtable_lookup_fast(&head->ht,
                                   fl_key_get_start(&skb_mkey, &head->mask),
                                   head->ht_params);
-       if (f) {
+       if (f && !(f->flags & TCA_CLS_FLAGS_SKIP_SW)) {
                *res = f->res;
                return tcf_exts_exec(skb, &f->exts, res);
        }
@@ -524,7 +528,6 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
        struct cls_fl_filter *fnew;
        struct nlattr *tb[TCA_FLOWER_MAX + 1];
        struct fl_flow_mask mask = {};
-       u32 flags = 0;
        int err;
 
        if (!tca[TCA_OPTIONS])
@@ -552,8 +555,14 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
        }
        fnew->handle = handle;
 
-       if (tb[TCA_FLOWER_FLAGS])
-               flags = nla_get_u32(tb[TCA_FLOWER_FLAGS]);
+       if (tb[TCA_FLOWER_FLAGS]) {
+               fnew->flags = nla_get_u32(tb[TCA_FLOWER_FLAGS]);
+
+               if (!tc_flags_valid(fnew->flags)) {
+                       err = -EINVAL;
+                       goto errout;
+               }
+       }
 
        err = fl_set_parms(net, tp, fnew, &mask, base, tb, tca[TCA_RATE], ovr);
        if (err)
@@ -563,10 +572,12 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
        if (err)
                goto errout;
 
-       err = rhashtable_insert_fast(&head->ht, &fnew->ht_node,
-                                    head->ht_params);
-       if (err)
-               goto errout;
+       if (!(fnew->flags & TCA_CLS_FLAGS_SKIP_SW)) {
+               err = rhashtable_insert_fast(&head->ht, &fnew->ht_node,
+                                            head->ht_params);
+               if (err)
+                       goto errout;
+       }
 
        fl_hw_replace_filter(tp,
                             &head->dissector,
@@ -574,7 +585,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
                             &fnew->key,
                             &fnew->exts,
                             (unsigned long)fnew,
-                            flags);
+                            fnew->flags);
 
        if (fold) {
                rhashtable_remove_fast(&head->ht, &fold->ht_node,
@@ -734,6 +745,8 @@ static int fl_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
                                  sizeof(key->tp.dst))))
                goto nla_put_failure;
 
+       nla_put_u32(skb, TCA_FLOWER_FLAGS, f->flags);
+
        if (tcf_exts_dump(skb, &f->exts))
                goto nla_put_failure;