flow_offload: add flow action infrastructure

This new infrastructure defines the nic actions that you can perform
from existing network drivers. This infrastructure allows us to avoid a
direct dependency with the native software TC action representation.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/flow_offload.h

@@ -100,11 +100,78 @@ 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);
 
-struct flow_rule {
-	struct flow_match	match;
+enum flow_action_id {
+	FLOW_ACTION_ACCEPT		= 0,
+	FLOW_ACTION_DROP,
+	FLOW_ACTION_TRAP,
+	FLOW_ACTION_GOTO,
+	FLOW_ACTION_REDIRECT,
+	FLOW_ACTION_MIRRED,
+	FLOW_ACTION_VLAN_PUSH,
+	FLOW_ACTION_VLAN_POP,
+	FLOW_ACTION_VLAN_MANGLE,
+	FLOW_ACTION_TUNNEL_ENCAP,
+	FLOW_ACTION_TUNNEL_DECAP,
+	FLOW_ACTION_MANGLE,
+	FLOW_ACTION_ADD,
+	FLOW_ACTION_CSUM,
+	FLOW_ACTION_MARK,
 };
 
-struct flow_rule *flow_rule_alloc(void);
+/* 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_action_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_entry {
+	enum flow_action_id		id;
+	union {
+		u32			chain_index;	/* FLOW_ACTION_GOTO */
+		struct net_device	*dev;		/* FLOW_ACTION_REDIRECT */
+		struct {				/* FLOW_ACTION_VLAN */
+			u16		vid;
+			__be16		proto;
+			u8		prio;
+		} vlan;
+		struct {				/* FLOW_ACTION_PACKET_EDIT */
+			enum flow_action_mangle_base htype;
+			u32		offset;
+			u32		mask;
+			u32		val;
+		} mangle;
+		const struct ip_tunnel_info *tunnel;	/* FLOW_ACTION_TUNNEL_ENCAP */
+		u32			csum_flags;	/* FLOW_ACTION_CSUM */
+		u32			mark;		/* FLOW_ACTION_MARK */
+	};
+};
+
+struct flow_action {
+	unsigned int			num_entries;
+	struct flow_action_entry 	entries[0];
+};
+
+static inline bool flow_action_has_entries(const struct flow_action *action)
+{
+	return action->num_entries;
+}
+
+#define flow_action_for_each(__i, __act, __actions)			\
+        for (__i = 0, __act = &(__actions)->entries[0]; __i < (__actions)->num_entries; __act = &(__actions)->entries[__i++])
+
+struct flow_rule {
+	struct flow_match	match;
+	struct flow_action	action;
+};
+
+struct flow_rule *flow_rule_alloc(unsigned int num_actions);
 
 static inline bool flow_rule_match_key(const struct flow_rule *rule,
 				       enum flow_dissector_key_id key)

include/net/pkt_cls.h

@@ -622,6 +622,7 @@ tcf_match_indev(struct sk_buff *skb, int ifindex)
 
 int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type,
 		     void *type_data, bool err_stop);
+unsigned int tcf_exts_num_actions(struct tcf_exts *exts);
 
 enum tc_block_command {
 	TC_BLOCK_BIND,

net/core/flow_offload.c

@@ -3,9 +3,19 @@
 #include <linux/slab.h>
 #include <net/flow_offload.h>
 
-struct flow_rule *flow_rule_alloc(void)
+struct flow_rule *flow_rule_alloc(unsigned int num_actions)
 {
-	return kzalloc(sizeof(struct flow_rule), GFP_KERNEL);
+	struct flow_rule *rule;
+
+	rule = kzalloc(sizeof(struct flow_rule) +
+		       sizeof(struct flow_action_entry) * num_actions,
+		       GFP_KERNEL);
+	if (!rule)
+		return NULL;
+
+	rule->action.num_entries = num_actions;
+
+	return rule;
 }
 EXPORT_SYMBOL(flow_rule_alloc);
 

net/sched/cls_api.c

@@ -31,6 +31,7 @@
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <net/pkt_cls.h>
+#include <net/tc_act/tc_pedit.h>
 
 extern const struct nla_policy rtm_tca_policy[TCA_MAX + 1];
 
@@ -2515,6 +2516,22 @@ int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type,
 }
 EXPORT_SYMBOL(tc_setup_cb_call);
 
+unsigned int tcf_exts_num_actions(struct tcf_exts *exts)
+{
+	unsigned int num_acts = 0;
+	struct tc_action *act;
+	int i;
+
+	tcf_exts_for_each_action(i, act, exts) {
+		if (is_tcf_pedit(act))
+			num_acts += tcf_pedit_nkeys(act);
+		else
+			num_acts++;
+	}
+	return num_acts;
+}
+EXPORT_SYMBOL(tcf_exts_num_actions);
+
 static __net_init int tcf_net_init(struct net *net)
 {
 	struct tcf_net *tn = net_generic(net, tcf_net_id);

net/sched/cls_flower.c

@@ -381,7 +381,7 @@ static int fl_hw_replace_filter(struct tcf_proto *tp,
 	bool skip_sw = tc_skip_sw(f->flags);
 	int err;
 
-	cls_flower.rule = flow_rule_alloc();
+	cls_flower.rule = flow_rule_alloc(tcf_exts_num_actions(&f->exts));
 	if (!cls_flower.rule)
 		return -ENOMEM;
 
@@ -1469,7 +1469,8 @@ static int fl_reoffload(struct tcf_proto *tp, bool add, tc_setup_cb_t *cb,
 			if (tc_skip_hw(f->flags))
 				continue;
 
-			cls_flower.rule = flow_rule_alloc();
+			cls_flower.rule =
+				flow_rule_alloc(tcf_exts_num_actions(&f->exts));
 			if (!cls_flower.rule)
 				return -ENOMEM;
 
@@ -1508,7 +1509,7 @@ static int fl_hw_create_tmplt(struct tcf_chain *chain,
 	struct tcf_block *block = chain->block;
 	struct tcf_exts dummy_exts = { 0, };
 
-	cls_flower.rule = flow_rule_alloc();
+	cls_flower.rule = flow_rule_alloc(0);
 	if (!cls_flower.rule)
 		return -ENOMEM;