net: sched: implement terse dump support in act

Extend tcf_action_dump() with boolean argument 'terse' that is used to
request terse-mode action dump. In terse mode only essential data needed to
identify particular action (action kind, cookie, etc.) and its stats is put
to resulting skb and everything else is omitted. Implement
tcf_exts_terse_dump() helper in cls API that is intended to be used to
request terse dump of all exts (actions) attached to the filter.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/act_api.h

@@ -193,7 +193,7 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 				    bool rtnl_held,
 				    struct netlink_ext_ack *extack);
 int tcf_action_dump(struct sk_buff *skb, struct tc_action *actions[], int bind,
-		    int ref);
+		    int ref, bool terse);
 int tcf_action_dump_old(struct sk_buff *skb, struct tc_action *a, int, int);
 int tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int, int);
 

include/net/pkt_cls.h

@@ -325,6 +325,7 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp,
 void tcf_exts_destroy(struct tcf_exts *exts);
 void tcf_exts_change(struct tcf_exts *dst, struct tcf_exts *src);
 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts);
+int tcf_exts_terse_dump(struct sk_buff *skb, struct tcf_exts *exts);
 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts);
 
 /**

net/sched/act_api.c

@@ -766,12 +766,10 @@ tcf_action_dump_old(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 	return a->ops->dump(skb, a, bind, ref);
 }
 
-int
-tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
+static int
+tcf_action_dump_terse(struct sk_buff *skb, struct tc_action *a)
 {
-	int err = -EINVAL;
 	unsigned char *b = skb_tail_pointer(skb);
-	struct nlattr *nest;
 	struct tc_cookie *cookie;
 
 	if (nla_put_string(skb, TCA_KIND, a->ops->kind))
@@ -789,6 +787,23 @@ tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 	}
 	rcu_read_unlock();
 
+	return 0;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+int
+tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
+{
+	int err = -EINVAL;
+	unsigned char *b = skb_tail_pointer(skb);
+	struct nlattr *nest;
+
+	if (tcf_action_dump_terse(skb, a))
+		goto nla_put_failure;
+
 	if (a->hw_stats != TCA_ACT_HW_STATS_ANY &&
 	    nla_put_bitfield32(skb, TCA_ACT_HW_STATS,
 			       a->hw_stats, TCA_ACT_HW_STATS_ANY))
@@ -820,7 +835,7 @@ tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 EXPORT_SYMBOL(tcf_action_dump_1);
 
 int tcf_action_dump(struct sk_buff *skb, struct tc_action *actions[],
-		    int bind, int ref)
+		    int bind, int ref, bool terse)
 {
 	struct tc_action *a;
 	int err = -EINVAL, i;
@@ -831,7 +846,8 @@ int tcf_action_dump(struct sk_buff *skb, struct tc_action *actions[],
 		nest = nla_nest_start_noflag(skb, i + 1);
 		if (nest == NULL)
 			goto nla_put_failure;
-		err = tcf_action_dump_1(skb, a, bind, ref);
+		err = terse ? tcf_action_dump_terse(skb, a) :
+			tcf_action_dump_1(skb, a, bind, ref);
 		if (err < 0)
 			goto errout;
 		nla_nest_end(skb, nest);
@@ -1133,7 +1149,7 @@ static int tca_get_fill(struct sk_buff *skb, struct tc_action *actions[],
 	if (!nest)
 		goto out_nlmsg_trim;
 
-	if (tcf_action_dump(skb, actions, bind, ref) < 0)
+	if (tcf_action_dump(skb, actions, bind, ref, false) < 0)
 		goto out_nlmsg_trim;
 
 	nla_nest_end(skb, nest);

net/sched/cls_api.c

@@ -3179,7 +3179,8 @@ int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
 			if (nest == NULL)
 				goto nla_put_failure;
 
-			if (tcf_action_dump(skb, exts->actions, 0, 0) < 0)
+			if (tcf_action_dump(skb, exts->actions, 0, 0, false)
+			    < 0)
 				goto nla_put_failure;
 			nla_nest_end(skb, nest);
 		} else if (exts->police) {
@@ -3203,6 +3204,31 @@ int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
 }
 EXPORT_SYMBOL(tcf_exts_dump);
 
+int tcf_exts_terse_dump(struct sk_buff *skb, struct tcf_exts *exts)
+{
+#ifdef CONFIG_NET_CLS_ACT
+	struct nlattr *nest;
+
+	if (!exts->action || !tcf_exts_has_actions(exts))
+		return 0;
+
+	nest = nla_nest_start_noflag(skb, exts->action);
+	if (!nest)
+		goto nla_put_failure;
+
+	if (tcf_action_dump(skb, exts->actions, 0, 0, true) < 0)
+		goto nla_put_failure;
+	nla_nest_end(skb, nest);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(skb, nest);
+	return -1;
+#else
+	return 0;
+#endif
+}
+EXPORT_SYMBOL(tcf_exts_terse_dump);
 
 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
 {