Subject: [PATCH RFC,net-next 03/10] flow_dissector: add flow action infrastructure

From: Pablo Neira Ayuso <[email-masked]>
Date: Tue, 25 Sep 2018 21:19:54 +0200

This patch adds new infrastructure that defines actions that you can
perform in existing network drivers. This infrastructure allows us to
avoid the direct dependency with the software TC action infrastructure.

Signed-off-by: Pablo Neira Ayuso <[email-masked]>
---
 include/net/flow_dissector.h | 70 ++++++++++++++++++++++++++++++++++++++++++++
 net/core/flow_dissector.c    | 18 ++++++++++++
 2 files changed, 88 insertions(+)

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 965a82b8d881..925c208816f1 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -402,8 +402,78 @@ void flow_rule_match_enc_keyid(const struct flow_rule *rule,
 void flow_rule_match_enc_opts(const struct flow_rule *rule,
 			      struct flow_match_enc_opts *out);
 
+enum flow_action_key_id {
+	FLOW_ACTION_KEY_ACCEPT		= 0,
+	FLOW_ACTION_KEY_DROP,
+	FLOW_ACTION_KEY_TRAP,
+	FLOW_ACTION_KEY_GOTO,
+	FLOW_ACTION_KEY_REDIRECT,
+	FLOW_ACTION_KEY_MIRRED,
+	FLOW_ACTION_KEY_VLAN_PUSH,
+	FLOW_ACTION_KEY_VLAN_POP,
+	FLOW_ACTION_KEY_VLAN_MANGLE,
+	FLOW_ACTION_KEY_TUNNEL_ENCAP,
+	FLOW_ACTION_KEY_TUNNEL_DECAP,
+	FLOW_ACTION_KEY_MANGLE,
+	FLOW_ACTION_KEY_ADD,
+	FLOW_ACTION_KEY_CSUM,
+	FLOW_ACTION_KEY_MARK,
+};
+
+/* This is mirroring enum pedit_header_type definition for easy mapping between
+ * tc pedit action. Legacy TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK is mapped to
+ * FLOW_ACT_MANGLE_UNSPEC, which is supported by no driver.
+ */
+enum flow_act_mangle_base {
+	FLOW_ACT_MANGLE_UNSPEC		= 0,
+	FLOW_ACT_MANGLE_HDR_TYPE_ETH,
+	FLOW_ACT_MANGLE_HDR_TYPE_IP4,
+	FLOW_ACT_MANGLE_HDR_TYPE_IP6,
+	FLOW_ACT_MANGLE_HDR_TYPE_TCP,
+	FLOW_ACT_MANGLE_HDR_TYPE_UDP,
+};
+
+struct flow_action_key {
+	enum flow_action_key_id		id;
+	union {
+		u32			chain_index;	/* FLOW_ACTION_KEY_GOTO */
+		struct net_device	*dev;		/* FLOW_ACTION_KEY_REDIRECT */
+		struct {				/* FLOW_ACTION_KEY_VLAN */
+			u16		vid;
+			__be16		proto;
+			u8		prio;
+		} vlan;
+		struct {				/* FLOW_ACTION_KEY_PACKET_EDIT */
+			enum flow_act_mangle_base htype;
+			u32		offset;
+			u32		mask;
+			u32		val;
+		} mangle;
+		const struct ip_tunnel_info *tunnel;	/* FLOW_ACTION_KEY_TUNNEL_ENCAP */
+		u32			csum_flags;	/* FLOW_ACTION_KEY_CSUM */
+		u32			mark;		/* FLOW_ACTION_KEY_MARK */
+	};
+};
+
+struct flow_action {
+	int			num_keys;
+	struct flow_action_key	*keys;
+};
+
+int flow_action_init(struct flow_action *flow_action, int num_acts);
+void flow_action_free(struct flow_action *flow_action);
+
+static inline bool flow_action_has_keys(const struct flow_action *action)
+{
+	return action->num_keys;
+}
+
+#define flow_action_for_each(__i, __act, __actions)			\
+        for (__i = 0, __act = &(__actions)->keys[0]; __i < (__actions)->num_keys; __act = &(__actions)->keys[++__i])
+
 struct flow_rule {
 	struct flow_match	match;
+	struct flow_action	action;
 };
 
 static inline bool flow_rule_match_key(const struct flow_rule *rule,
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 5a22381efccc..e25b235a8e10 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -195,6 +195,24 @@ void flow_rule_match_enc_opts(const struct flow_rule *rule,
 }
 EXPORT_SYMBOL(flow_rule_match_enc_opts);
 
+int flow_action_init(struct flow_action *flow_action, int num_acts)
+{
+	flow_action->keys = kmalloc(sizeof(struct flow_action_key) * num_acts,
+				    GFP_KERNEL);
+	if (!flow_action->keys)
+		return -ENOMEM;
+
+	flow_action->num_keys = num_acts;
+	return 0;
+}
+EXPORT_SYMBOL(flow_action_init);
+
+void flow_action_free(struct flow_action *flow_action)
+{
+	kfree(flow_action->keys);
+}
+EXPORT_SYMBOL(flow_action_free);
+
 /**
  * skb_flow_get_be16 - extract be16 entity
  * @skb: sk_buff to extract from
-- 
2.11.0