From: Jiri Pirko <jiri@mellanox.com>
Date: Wed, 17 May 2017 11:08:03 +0200
Subject: net: sched: add termination action to allow goto chain
Patch-mainline: v4.13-rc1
Git-commit: db50514f9a9c7ef1f17e9921b1cc0902746872f3
References: bsc#1056657 FATE#322189 bsc#1056653 FATE#322190 bsc#1056787

Introduce new type of termination action called "goto_chain". This allows
user to specify a chain to be processed. This action type is
then processed as a return value in tcf_classify loop in similar
way as "reclassify" is, only it does not reset to the first filter
in chain but rather reset to the first filter of the desired chain.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Benjamin Poirier <bpoirier@suse.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/net/act_api.h        |    1 +
 include/net/sch_generic.h    |    9 +++++++--
 include/uapi/linux/pkt_cls.h |    1 +
 net/sched/act_api.c          |   40 ++++++++++++++++++++++++++++++++++++++++
 net/sched/cls_api.c          |    6 +++++-
 5 files changed, 54 insertions(+), 3 deletions(-)

--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -42,6 +42,7 @@ struct tc_action {
 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
 	struct gnet_stats_queue __percpu *cpu_qstats;
 	struct tc_cookie	*act_cookie;
+	struct tcf_chain	*goto_chain;
 };
 #define tcf_head	common.tcfa_head
 #define tcf_index	common.tcfa_index
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -193,8 +193,13 @@ struct Qdisc_ops {
 
 
 struct tcf_result {
-	unsigned long	class;
-	u32		classid;
+	union {
+		struct {
+			unsigned long	class;
+			u32		classid;
+		};
+		const struct tcf_proto *goto_tp;
+	};
 };
 
 struct tcf_proto_ops {
--- a/include/uapi/linux/pkt_cls.h
+++ b/include/uapi/linux/pkt_cls.h
@@ -51,6 +51,7 @@ enum {
 	(((combined) & (~TC_ACT_EXT_VAL_MASK)) == opcode)
 
 #define TC_ACT_JUMP __TC_ACT_EXT(1)
+#define TC_ACT_GOTO_CHAIN __TC_ACT_EXT(2)
 
 /* Action type identifiers*/
 enum {
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -28,6 +28,31 @@
 #include <net/act_api.h>
 #include <net/netlink.h>
 
+static int tcf_action_goto_chain_init(struct tc_action *a, struct tcf_proto *tp)
+{
+	u32 chain_index = a->tcfa_action & TC_ACT_EXT_VAL_MASK;
+
+	if (!tp)
+		return -EINVAL;
+	a->goto_chain = tcf_chain_get(tp->chain->block, chain_index);
+	if (!a->goto_chain)
+		return -ENOMEM;
+	return 0;
+}
+
+static void tcf_action_goto_chain_fini(struct tc_action *a)
+{
+	tcf_chain_put(a->goto_chain);
+}
+
+static void tcf_action_goto_chain_exec(const struct tc_action *a,
+				       struct tcf_result *res)
+{
+	const struct tcf_chain *chain = a->goto_chain;
+
+	res->goto_tp = rcu_dereference_bh(chain->filter_chain);
+}
+
 static void free_tcf(struct rcu_head *head)
 {
 	struct tc_action *p = container_of(head, struct tc_action, tcfa_rcu);
@@ -39,6 +64,8 @@ static void free_tcf(struct rcu_head *he
 		kfree(p->act_cookie->data);
 		kfree(p->act_cookie);
 	}
+	if (p->goto_chain)
+		tcf_action_goto_chain_fini(p);
 
 	kfree(p);
 }
@@ -465,6 +492,8 @@ repeat:
 				else /* faulty graph, stop pipeline */
 					return TC_ACT_OK;
 			}
+		} else if (TC_ACT_EXT_CMP(ret, TC_ACT_GOTO_CHAIN)) {
+			tcf_action_goto_chain_exec(a, res);
 		}
 
 		if (ret != TC_ACT_PIPE)
@@ -657,6 +686,17 @@ struct tc_action *tcf_action_init_1(stru
 	if (err != ACT_P_CREATED)
 		module_put(a_o->owner);
 
+	if (TC_ACT_EXT_CMP(a->tcfa_action, TC_ACT_GOTO_CHAIN)) {
+		err = tcf_action_goto_chain_init(a, tp);
+		if (err) {
+			LIST_HEAD(actions);
+
+			list_add_tail(&a->list, &actions);
+			tcf_action_destroy(&actions, bind);
+			return ERR_PTR(err);
+		}
+	}
+
 	return a;
 
 err_mod:
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -307,8 +307,12 @@ reclassify:
 
 		err = tp->classify(skb, tp, res);
 #ifdef CONFIG_NET_CLS_ACT
-		if (unlikely(err == TC_ACT_RECLASSIFY && !compat_mode))
+		if (unlikely(err == TC_ACT_RECLASSIFY && !compat_mode)) {
 			goto reset;
+		} else if (unlikely(TC_ACT_EXT_CMP(err, TC_ACT_GOTO_CHAIN))) {
+			old_tp = res->goto_tp;
+			goto reset;
+		}
 #endif
 		if (err >= 0)
 			return err;