flow_offload: add skip_hw and skip_sw to control if offload the action

We add skip_hw and skip_sw for user to control if offload the action
to hardware.

We also add in_hw_count for user to indicate if the action is offloaded
to any hardware.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/act_api.h

@@ -44,6 +44,7 @@ struct tc_action {
 	u8			hw_stats;
 	u8			used_hw_stats;
 	bool			used_hw_stats_valid;
+	u32			in_hw_count;
 };
 #define tcf_index	common.tcfa_index
 #define tcf_refcnt	common.tcfa_refcnt

include/uapi/linux/pkt_cls.h

@@ -19,13 +19,16 @@ enum {
 	TCA_ACT_FLAGS,
 	TCA_ACT_HW_STATS,
 	TCA_ACT_USED_HW_STATS,
+	TCA_ACT_IN_HW_COUNT,
 	__TCA_ACT_MAX
 };
 
 /* See other TCA_ACT_FLAGS_ * flags in include/net/act_api.h. */
-#define TCA_ACT_FLAGS_NO_PERCPU_STATS 1 /* Don't use percpu allocator for
-					 * actions stats.
-					 */
+#define TCA_ACT_FLAGS_NO_PERCPU_STATS (1 << 0) /* Don't use percpu allocator for
+						* actions stats.
+						*/
+#define TCA_ACT_FLAGS_SKIP_HW	(1 << 1) /* don't offload action to HW */
+#define TCA_ACT_FLAGS_SKIP_SW	(1 << 2) /* don't use action in SW */
 
 /* tca HW stats type
  * When user does not pass the attribute, he does not care.

net/sched/act_api.c

@@ -131,6 +131,12 @@ static void free_tcf(struct tc_action *p)
 	kfree(p);
 }
 
+static void offload_action_hw_count_set(struct tc_action *act,
+					u32 hw_count)
+{
+	act->in_hw_count = hw_count;
+}
+
 static unsigned int tcf_offload_act_num_actions_single(struct tc_action *act)
 {
 	if (is_tcf_pedit(act))
@@ -139,6 +145,29 @@ static unsigned int tcf_offload_act_num_actions_single(struct tc_action *act)
 		return 1;
 }
 
+static bool tc_act_skip_hw(u32 flags)
+{
+	return (flags & TCA_ACT_FLAGS_SKIP_HW) ? true : false;
+}
+
+static bool tc_act_skip_sw(u32 flags)
+{
+	return (flags & TCA_ACT_FLAGS_SKIP_SW) ? true : false;
+}
+
+static bool tc_act_in_hw(struct tc_action *act)
+{
+	return !!act->in_hw_count;
+}
+
+/* SKIP_HW and SKIP_SW are mutually exclusive flags. */
+static bool tc_act_flags_valid(u32 flags)
+{
+	flags &= TCA_ACT_FLAGS_SKIP_HW | TCA_ACT_FLAGS_SKIP_SW;
+
+	return flags ^ (TCA_ACT_FLAGS_SKIP_HW | TCA_ACT_FLAGS_SKIP_SW);
+}
+
 static int offload_action_init(struct flow_offload_action *fl_action,
 			       struct tc_action *act,
 			       enum offload_act_command  cmd,
@@ -155,6 +184,7 @@ static int offload_action_init(struct flow_offload_action *fl_action,
 }
 
 static int tcf_action_offload_cmd(struct flow_offload_action *fl_act,
+				  u32 *hw_count,
 				  struct netlink_ext_ack *extack)
 {
 	int err;
@@ -164,6 +194,9 @@ static int tcf_action_offload_cmd(struct flow_offload_action *fl_act,
 	if (err < 0)
 		return err;
 
+	if (hw_count)
+		*hw_count = err;
+
 	return 0;
 }
 
@@ -171,12 +204,17 @@ static int tcf_action_offload_cmd(struct flow_offload_action *fl_act,
 static int tcf_action_offload_add(struct tc_action *action,
 				  struct netlink_ext_ack *extack)
 {
+	bool skip_sw = tc_act_skip_sw(action->tcfa_flags);
 	struct tc_action *actions[TCA_ACT_MAX_PRIO] = {
 		[0] = action,
 	};
 	struct flow_offload_action *fl_action;
+	u32 in_hw_count = 0;
 	int num, err = 0;
 
+	if (tc_act_skip_hw(action->tcfa_flags))
+		return 0;
+
 	num = tcf_offload_act_num_actions_single(action);
 	fl_action = offload_action_alloc(num);
 	if (!fl_action)
@@ -193,7 +231,13 @@ static int tcf_action_offload_add(struct tc_action *action,
 		goto fl_err;
 	}
 
-	err = tcf_action_offload_cmd(fl_action, extack);
+	err = tcf_action_offload_cmd(fl_action, &in_hw_count, extack);
+	if (!err)
+		offload_action_hw_count_set(action, in_hw_count);
+
+	if (skip_sw && !tc_act_in_hw(action))
+		err = -EINVAL;
+
 	tc_cleanup_offload_action(&fl_action->action);
 
 fl_err:
@@ -205,13 +249,24 @@ static int tcf_action_offload_add(struct tc_action *action,
 static int tcf_action_offload_del(struct tc_action *action)
 {
 	struct flow_offload_action fl_act = {};
+	u32 in_hw_count = 0;
 	int err = 0;
 
+	if (!tc_act_in_hw(action))
+		return 0;
+
 	err = offload_action_init(&fl_act, action, FLOW_ACT_DESTROY, NULL);
 	if (err)
 		return err;
 
-	return tcf_action_offload_cmd(&fl_act, NULL);
+	err = tcf_action_offload_cmd(&fl_act, &in_hw_count, NULL);
+	if (err)
+		return err;
+
+	if (action->in_hw_count != in_hw_count)
+		return -EINVAL;
+
+	return 0;
 }
 
 static void tcf_action_cleanup(struct tc_action *p)
@@ -821,6 +876,9 @@ int tcf_action_exec(struct sk_buff *skb, struct tc_action **actions,
 			jmp_prgcnt -= 1;
 			continue;
 		}
+
+		if (tc_act_skip_sw(a->tcfa_flags))
+			continue;
 repeat:
 		ret = a->ops->act(skb, a, res);
 		if (ret == TC_ACT_REPEAT)
@@ -926,6 +984,9 @@ tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 			       a->tcfa_flags, a->tcfa_flags))
 		goto nla_put_failure;
 
+	if (nla_put_u32(skb, TCA_ACT_IN_HW_COUNT, a->in_hw_count))
+		goto nla_put_failure;
+
 	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
 	if (nest == NULL)
 		goto nla_put_failure;
@@ -1005,7 +1066,9 @@ static const struct nla_policy tcf_action_policy[TCA_ACT_MAX + 1] = {
 	[TCA_ACT_COOKIE]	= { .type = NLA_BINARY,
 				    .len = TC_COOKIE_MAX_SIZE },
 	[TCA_ACT_OPTIONS]	= { .type = NLA_NESTED },
-	[TCA_ACT_FLAGS]		= NLA_POLICY_BITFIELD32(TCA_ACT_FLAGS_NO_PERCPU_STATS),
+	[TCA_ACT_FLAGS]		= NLA_POLICY_BITFIELD32(TCA_ACT_FLAGS_NO_PERCPU_STATS |
+							TCA_ACT_FLAGS_SKIP_HW |
+							TCA_ACT_FLAGS_SKIP_SW),
 	[TCA_ACT_HW_STATS]	= NLA_POLICY_BITFIELD32(TCA_ACT_HW_STATS_ANY),
 };
 
@@ -1118,8 +1181,13 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 			}
 		}
 		hw_stats = tcf_action_hw_stats_get(tb[TCA_ACT_HW_STATS]);
-		if (tb[TCA_ACT_FLAGS])
+		if (tb[TCA_ACT_FLAGS]) {
 			userflags = nla_get_bitfield32(tb[TCA_ACT_FLAGS]);
+			if (!tc_act_flags_valid(userflags.value)) {
+				err = -EINVAL;
+				goto err_out;
+			}
+		}
 
 		err = a_o->init(net, tb[TCA_ACT_OPTIONS], est, &a, tp,
 				userflags.value | flags, extack);
@@ -1194,8 +1262,11 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 		sz += tcf_action_fill_size(act);
 		/* Start from index 0 */
 		actions[i - 1] = act;
-		if (!tc_act_bind(flags))
-			tcf_action_offload_add(act, extack);
+		if (!tc_act_bind(flags)) {
+			err = tcf_action_offload_add(act, extack);
+			if (tc_act_skip_sw(act->tcfa_flags) && err)
+				goto err;
+		}
 	}
 
 	/* We have to commit them all together, because if any error happened in