Merge branch 'mlxsw-Implement-ACL-dropped-packets-identification'

Jiri Pirko says:

====================
mlxsw: Implement ACL-dropped packets identification

mlxsw hardware allows to insert a ACL-drop action with a value defined
by user that would be later on passed with a dropped packet.

To implement this, use the existing TC action cookie and pass it to the
driver. As the cookie format coming down from TC and the mlxsw HW cookie
format is different, do the mapping of these two using idr and rhashtable.

The cookie is passed up from the HW through devlink_trap_report() to
drop_monitor code. A new metadata type is used for that.

Example:
$ tc qdisc add dev enp0s16np1 clsact
$ tc filter add dev enp0s16np1 ingress protocol ip pref 10 flower skip_sw dst_ip 192.168.1.2 action drop cookie 3b45fa38c8
                                                                                                                ^^^^^^^^^^
$ devlink trap set pci/0000:00:10.0 trap acl action trap
$ dropwatch
Initializing null lookup method
dropwatch> set hw true
setting hardware drops monitoring to 1
dropwatch> set alertmode packet
Setting alert mode
Alert mode successfully set
dropwatch> start
Enabling monitoring...
Kernel monitoring activated.
Issue Ctrl-C to stop monitoring
drop at: ingress_flow_action_drop (acl_drops)
origin: hardware
input port ifindex: 30
input port name: enp0s16np1
cookie: 3b45fa38c8    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
timestamp: Fri Jan 24 17:10:53 2020 715387671 nsec
protocol: 0x800
length: 98
original length: 98

This way the user may insert multiple drop rules and monitor the dropped
packets with the information of which action caused the drop.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core.h

@@ -473,7 +473,10 @@ enum mlxsw_devlink_param_id {
 };
 
 struct mlxsw_skb_cb {
-	struct mlxsw_tx_info tx_info;
+	union {
+		struct mlxsw_tx_info tx_info;
+		u32 cookie_index; /* Only used during receive */
+	};
 };
 
 static inline struct mlxsw_skb_cb *mlxsw_skb_cb(struct sk_buff *skb)

drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c

@@ -7,6 +7,9 @@
 #include <linux/errno.h>
 #include <linux/rhashtable.h>
 #include <linux/list.h>
+#include <linux/idr.h>
+#include <linux/refcount.h>
+#include <net/flow_offload.h>
 
 #include "item.h"
 #include "trap.h"
@@ -63,6 +66,8 @@ struct mlxsw_afa {
 	void *ops_priv;
 	struct rhashtable set_ht;
 	struct rhashtable fwd_entry_ht;
+	struct rhashtable cookie_ht;
+	struct idr cookie_idr;
 };
 
 #define MLXSW_AFA_SET_LEN 0xA8
@@ -121,6 +126,55 @@ static const struct rhashtable_params mlxsw_afa_fwd_entry_ht_params = {
 	.automatic_shrinking = true,
 };
 
+struct mlxsw_afa_cookie {
+	struct rhash_head ht_node;
+	refcount_t ref_count;
+	struct rcu_head rcu;
+	u32 cookie_index;
+	struct flow_action_cookie fa_cookie;
+};
+
+static u32 mlxsw_afa_cookie_hash(const struct flow_action_cookie *fa_cookie,
+				 u32 seed)
+{
+	return jhash2((u32 *) fa_cookie->cookie,
+		      fa_cookie->cookie_len / sizeof(u32), seed);
+}
+
+static u32 mlxsw_afa_cookie_key_hashfn(const void *data, u32 len, u32 seed)
+{
+	const struct flow_action_cookie *fa_cookie = data;
+
+	return mlxsw_afa_cookie_hash(fa_cookie, seed);
+}
+
+static u32 mlxsw_afa_cookie_obj_hashfn(const void *data, u32 len, u32 seed)
+{
+	const struct mlxsw_afa_cookie *cookie = data;
+
+	return mlxsw_afa_cookie_hash(&cookie->fa_cookie, seed);
+}
+
+static int mlxsw_afa_cookie_obj_cmpfn(struct rhashtable_compare_arg *arg,
+				      const void *obj)
+{
+	const struct flow_action_cookie *fa_cookie = arg->key;
+	const struct mlxsw_afa_cookie *cookie = obj;
+
+	if (cookie->fa_cookie.cookie_len == fa_cookie->cookie_len)
+		return memcmp(cookie->fa_cookie.cookie, fa_cookie->cookie,
+			      fa_cookie->cookie_len);
+	return 1;
+}
+
+static const struct rhashtable_params mlxsw_afa_cookie_ht_params = {
+	.head_offset = offsetof(struct mlxsw_afa_cookie, ht_node),
+	.hashfn	= mlxsw_afa_cookie_key_hashfn,
+	.obj_hashfn = mlxsw_afa_cookie_obj_hashfn,
+	.obj_cmpfn = mlxsw_afa_cookie_obj_cmpfn,
+	.automatic_shrinking = true,
+};
+
 struct mlxsw_afa *mlxsw_afa_create(unsigned int max_acts_per_set,
 				   const struct mlxsw_afa_ops *ops,
 				   void *ops_priv)
@@ -138,11 +192,18 @@ struct mlxsw_afa *mlxsw_afa_create(unsigned int max_acts_per_set,
 			      &mlxsw_afa_fwd_entry_ht_params);
 	if (err)
 		goto err_fwd_entry_rhashtable_init;
+	err = rhashtable_init(&mlxsw_afa->cookie_ht,
+			      &mlxsw_afa_cookie_ht_params);
+	if (err)
+		goto err_cookie_rhashtable_init;
+	idr_init(&mlxsw_afa->cookie_idr);
 	mlxsw_afa->max_acts_per_set = max_acts_per_set;
 	mlxsw_afa->ops = ops;
 	mlxsw_afa->ops_priv = ops_priv;
 	return mlxsw_afa;
 
+err_cookie_rhashtable_init:
+	rhashtable_destroy(&mlxsw_afa->fwd_entry_ht);
 err_fwd_entry_rhashtable_init:
 	rhashtable_destroy(&mlxsw_afa->set_ht);
 err_set_rhashtable_init:
@@ -153,6 +214,9 @@ EXPORT_SYMBOL(mlxsw_afa_create);
 
 void mlxsw_afa_destroy(struct mlxsw_afa *mlxsw_afa)
 {
+	WARN_ON(!idr_is_empty(&mlxsw_afa->cookie_idr));
+	idr_destroy(&mlxsw_afa->cookie_idr);
+	rhashtable_destroy(&mlxsw_afa->cookie_ht);
 	rhashtable_destroy(&mlxsw_afa->fwd_entry_ht);
 	rhashtable_destroy(&mlxsw_afa->set_ht);
 	kfree(mlxsw_afa);
@@ -627,6 +691,151 @@ mlxsw_afa_counter_create(struct mlxsw_afa_block *block)
 	return ERR_PTR(err);
 }
 
+/* 20 bits is a maximum that hardware can handle in trap with userdef action
+ * and carry along with the trapped packet.
+ */
+#define MLXSW_AFA_COOKIE_INDEX_BITS 20
+#define MLXSW_AFA_COOKIE_INDEX_MAX ((1 << MLXSW_AFA_COOKIE_INDEX_BITS) - 1)
+
+static struct mlxsw_afa_cookie *
+mlxsw_afa_cookie_create(struct mlxsw_afa *mlxsw_afa,
+			const struct flow_action_cookie *fa_cookie)
+{
+	struct mlxsw_afa_cookie *cookie;
+	u32 cookie_index;
+	int err;
+
+	cookie = kzalloc(sizeof(*cookie) + fa_cookie->cookie_len, GFP_KERNEL);
+	if (!cookie)
+		return ERR_PTR(-ENOMEM);
+	refcount_set(&cookie->ref_count, 1);
+	memcpy(&cookie->fa_cookie, fa_cookie,
+	       sizeof(*fa_cookie) + fa_cookie->cookie_len);
+
+	err = rhashtable_insert_fast(&mlxsw_afa->cookie_ht, &cookie->ht_node,
+				     mlxsw_afa_cookie_ht_params);
+	if (err)
+		goto err_rhashtable_insert;
+
+	/* Start cookie indexes with 1. Leave the 0 index unused. Packets
+	 * that come from the HW which are not dropped by drop-with-cookie
+	 * action are going to pass cookie_index 0 to lookup.
+	 */
+	cookie_index = 1;
+	err = idr_alloc_u32(&mlxsw_afa->cookie_idr, cookie, &cookie_index,
+			    MLXSW_AFA_COOKIE_INDEX_MAX, GFP_KERNEL);
+	if (err)
+		goto err_idr_alloc;
+	cookie->cookie_index = cookie_index;
+	return cookie;
+
+err_idr_alloc:
+	rhashtable_remove_fast(&mlxsw_afa->cookie_ht, &cookie->ht_node,
+			       mlxsw_afa_cookie_ht_params);
+err_rhashtable_insert:
+	kfree(cookie);
+	return ERR_PTR(err);
+}
+
+static void mlxsw_afa_cookie_destroy(struct mlxsw_afa *mlxsw_afa,
+				     struct mlxsw_afa_cookie *cookie)
+{
+	idr_remove(&mlxsw_afa->cookie_idr, cookie->cookie_index);
+	rhashtable_remove_fast(&mlxsw_afa->cookie_ht, &cookie->ht_node,
+			       mlxsw_afa_cookie_ht_params);
+	kfree_rcu(cookie, rcu);
+}
+
+static struct mlxsw_afa_cookie *
+mlxsw_afa_cookie_get(struct mlxsw_afa *mlxsw_afa,
+		     const struct flow_action_cookie *fa_cookie)
+{
+	struct mlxsw_afa_cookie *cookie;
+
+	cookie = rhashtable_lookup_fast(&mlxsw_afa->cookie_ht, fa_cookie,
+					mlxsw_afa_cookie_ht_params);
+	if (cookie) {
+		refcount_inc(&cookie->ref_count);
+		return cookie;
+	}
+	return mlxsw_afa_cookie_create(mlxsw_afa, fa_cookie);
+}
+
+static void mlxsw_afa_cookie_put(struct mlxsw_afa *mlxsw_afa,
+				 struct mlxsw_afa_cookie *cookie)
+{
+	if (!refcount_dec_and_test(&cookie->ref_count))
+		return;
+	mlxsw_afa_cookie_destroy(mlxsw_afa, cookie);
+}
+
+/* RCU read lock must be held */
+const struct flow_action_cookie *
+mlxsw_afa_cookie_lookup(struct mlxsw_afa *mlxsw_afa, u32 cookie_index)
+{
+	struct mlxsw_afa_cookie *cookie;
+
+	/* 0 index means no cookie */
+	if (!cookie_index)
+		return NULL;
+	cookie = idr_find(&mlxsw_afa->cookie_idr, cookie_index);
+	if (!cookie)
+		return NULL;
+	return &cookie->fa_cookie;
+}
+EXPORT_SYMBOL(mlxsw_afa_cookie_lookup);
+
+struct mlxsw_afa_cookie_ref {
+	struct mlxsw_afa_resource resource;
+	struct mlxsw_afa_cookie *cookie;
+};
+
+static void
+mlxsw_afa_cookie_ref_destroy(struct mlxsw_afa_block *block,
+			     struct mlxsw_afa_cookie_ref *cookie_ref)
+{
+	mlxsw_afa_resource_del(&cookie_ref->resource);
+	mlxsw_afa_cookie_put(block->afa, cookie_ref->cookie);
+	kfree(cookie_ref);
+}
+
+static void
+mlxsw_afa_cookie_ref_destructor(struct mlxsw_afa_block *block,
+				struct mlxsw_afa_resource *resource)
+{
+	struct mlxsw_afa_cookie_ref *cookie_ref;
+
+	cookie_ref = container_of(resource, struct mlxsw_afa_cookie_ref,
+				  resource);
+	mlxsw_afa_cookie_ref_destroy(block, cookie_ref);
+}
+
+static struct mlxsw_afa_cookie_ref *
+mlxsw_afa_cookie_ref_create(struct mlxsw_afa_block *block,
+			    const struct flow_action_cookie *fa_cookie)
+{
+	struct mlxsw_afa_cookie_ref *cookie_ref;
+	struct mlxsw_afa_cookie *cookie;
+	int err;
+
+	cookie_ref = kzalloc(sizeof(*cookie_ref), GFP_KERNEL);
+	if (!cookie_ref)
+		return ERR_PTR(-ENOMEM);
+	cookie = mlxsw_afa_cookie_get(block->afa, fa_cookie);
+	if (IS_ERR(cookie)) {
+		err = PTR_ERR(cookie);
+		goto err_cookie_get;
+	}
+	cookie_ref->cookie = cookie;
+	cookie_ref->resource.destructor = mlxsw_afa_cookie_ref_destructor;
+	mlxsw_afa_resource_add(block, &cookie_ref->resource);
+	return cookie_ref;
+
+err_cookie_get:
+	kfree(cookie_ref);
+	return ERR_PTR(err);
+}
+
 #define MLXSW_AFA_ONE_ACTION_LEN 32
 #define MLXSW_AFA_PAYLOAD_OFFSET 4
 
@@ -747,18 +956,25 @@ int mlxsw_afa_block_append_vlan_modify(struct mlxsw_afa_block *block,
 }
 EXPORT_SYMBOL(mlxsw_afa_block_append_vlan_modify);
 
-/* Trap Action
- * -----------
+/* Trap Action / Trap With Userdef Action
+ * --------------------------------------
  * The Trap action enables trapping / mirroring packets to the CPU
  * as well as discarding packets.
  * The ACL Trap / Discard separates the forward/discard control from CPU
  * trap control. In addition, the Trap / Discard action enables activating
  * SPAN (port mirroring).
+ *
+ * The Trap with userdef action action has the same functionality as
+ * the Trap action with addition of user defined value that can be set
+ * and used by higher layer applications.
  */
 
 #define MLXSW_AFA_TRAP_CODE 0x03
 #define MLXSW_AFA_TRAP_SIZE 1
 
+#define MLXSW_AFA_TRAPWU_CODE 0x04
+#define MLXSW_AFA_TRAPWU_SIZE 2
+
 enum mlxsw_afa_trap_trap_action {
 	MLXSW_AFA_TRAP_TRAP_ACTION_NOP = 0,
 	MLXSW_AFA_TRAP_TRAP_ACTION_TRAP = 2,
@@ -794,6 +1010,15 @@ MLXSW_ITEM32(afa, trap, mirror_agent, 0x08, 29, 3);
  */
 MLXSW_ITEM32(afa, trap, mirror_enable, 0x08, 24, 1);
 
+/* user_def_val
+ * Value for the SW usage. Can be used to pass information of which
+ * rule has caused a trap. This may be overwritten by later traps.
+ * This field does a set on the packet's user_def_val only if this
+ * is the first trap_id or if the trap_id has replaced the previous
+ * packet's trap_id.
+ */
+MLXSW_ITEM32(afa, trap, user_def_val, 0x0C, 0, 20);
+
 static inline void
 mlxsw_afa_trap_pack(char *payload,
 		    enum mlxsw_afa_trap_trap_action trap_action,
@@ -805,6 +1030,16 @@ mlxsw_afa_trap_pack(char *payload,
 	mlxsw_afa_trap_trap_id_set(payload, trap_id);
 }
 
+static inline void
+mlxsw_afa_trapwu_pack(char *payload,
+		      enum mlxsw_afa_trap_trap_action trap_action,
+		      enum mlxsw_afa_trap_forward_action forward_action,
+		      u16 trap_id, u32 user_def_val)
+{
+	mlxsw_afa_trap_pack(payload, trap_action, forward_action, trap_id);
+	mlxsw_afa_trap_user_def_val_set(payload, user_def_val);
+}
+
 static inline void
 mlxsw_afa_trap_mirror_pack(char *payload, bool mirror_enable,
 			   u8 mirror_agent)
@@ -813,7 +1048,8 @@ mlxsw_afa_trap_mirror_pack(char *payload, bool mirror_enable,
 	mlxsw_afa_trap_mirror_agent_set(payload, mirror_agent);
 }
 
-int mlxsw_afa_block_append_drop(struct mlxsw_afa_block *block, bool ingress)
+static int mlxsw_afa_block_append_drop_plain(struct mlxsw_afa_block *block,
+					     bool ingress)
 {
 	char *act = mlxsw_afa_block_append_action(block, MLXSW_AFA_TRAP_CODE,
 						  MLXSW_AFA_TRAP_SIZE);
@@ -826,6 +1062,53 @@ int mlxsw_afa_block_append_drop(struct mlxsw_afa_block *block, bool ingress)
 				      MLXSW_TRAP_ID_DISCARD_EGRESS_ACL);
 	return 0;
 }
+
+static int
+mlxsw_afa_block_append_drop_with_cookie(struct mlxsw_afa_block *block,
+					bool ingress,
+					const struct flow_action_cookie *fa_cookie,
+					struct netlink_ext_ack *extack)
+{
+	struct mlxsw_afa_cookie_ref *cookie_ref;
+	u32 cookie_index;
+	char *act;
+	int err;
+
+	cookie_ref = mlxsw_afa_cookie_ref_create(block, fa_cookie);
+	if (IS_ERR(cookie_ref)) {
+		NL_SET_ERR_MSG_MOD(extack, "Cannot create cookie for drop action");
+		return PTR_ERR(cookie_ref);
+	}
+	cookie_index = cookie_ref->cookie->cookie_index;
+
+	act = mlxsw_afa_block_append_action(block, MLXSW_AFA_TRAPWU_CODE,
+					    MLXSW_AFA_TRAPWU_SIZE);
+	if (IS_ERR(act)) {
+		NL_SET_ERR_MSG_MOD(extack, "Cannot append drop with cookie action");
+		err = PTR_ERR(act);
+		goto err_append_action;
+	}
+	mlxsw_afa_trapwu_pack(act, MLXSW_AFA_TRAP_TRAP_ACTION_TRAP,
+			      MLXSW_AFA_TRAP_FORWARD_ACTION_DISCARD,
+			      ingress ? MLXSW_TRAP_ID_DISCARD_INGRESS_ACL :
+					MLXSW_TRAP_ID_DISCARD_EGRESS_ACL,
+			      cookie_index);
+	return 0;
+
+err_append_action:
+	mlxsw_afa_cookie_ref_destroy(block, cookie_ref);
+	return err;
+}
+
+int mlxsw_afa_block_append_drop(struct mlxsw_afa_block *block, bool ingress,
+				const struct flow_action_cookie *fa_cookie,
+				struct netlink_ext_ack *extack)
+{
+	return fa_cookie ?
+	       mlxsw_afa_block_append_drop_with_cookie(block, ingress,
+						       fa_cookie, extack) :
+	       mlxsw_afa_block_append_drop_plain(block, ingress);
+}
 EXPORT_SYMBOL(mlxsw_afa_block_append_drop);
 
 int mlxsw_afa_block_append_trap(struct mlxsw_afa_block *block, u16 trap_id)