net-shapers: implement NL get operation

Introduce the basic infrastructure to implement the net-shaper
core functionality. Each network devices carries a net-shaper cache,
the NL get() operation fetches the data from such cache.

The cache is initially empty, will be fill by the set()/group()
operation implemented later and is destroyed at device cleanup time.

The net_shaper_fill_handle(), net_shaper_ctx_init(), and
net_shaper_generic_pre() implementations handle generic index type
attributes, despite the current caller always pass a constant value
to avoid more noise in later patches using them with different
attributes.

Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/ddd10fd645a9367803ad02fca4a5664ea5ace170.1728460186.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 120 insertions, 0 deletions

diff --git a/include/net/net_shaper.h b/include/net/net_shaper.h
new file mode 100644
index 000000000000..5c3f49b52fe9
--- /dev/null
+++ b/include/net/net_shaper.h
@@ -0,0 +1,120 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _NET_SHAPER_H_
+#define _NET_SHAPER_H_
+
+#include <linux/types.h>
+
+#include <uapi/linux/net_shaper.h>
+
+struct net_device;
+struct devlink;
+struct netlink_ext_ack;
+
+enum net_shaper_binding_type {
+	NET_SHAPER_BINDING_TYPE_NETDEV,
+	/* NET_SHAPER_BINDING_TYPE_DEVLINK_PORT */
+};
+
+struct net_shaper_binding {
+	enum net_shaper_binding_type type;
+	union {
+		struct net_device *netdev;
+		struct devlink *devlink;
+	};
+};
+
+struct net_shaper_handle {
+	enum net_shaper_scope scope;
+	u32 id;
+};
+
+/**
+ * struct net_shaper - represents a shaping node on the NIC H/W
+ * zeroed field are considered not set.
+ * @parent: Unique identifier for the shaper parent, usually implied
+ * @handle: Unique identifier for this shaper
+ * @metric: Specify if the rate limits refers to PPS or BPS
+ * @bw_min: Minimum guaranteed rate for this shaper
+ * @bw_max: Maximum peak rate allowed for this shaper
+ * @burst: Maximum burst for the peek rate of this shaper
+ * @priority: Scheduling priority for this shaper
+ * @weight: Scheduling weight for this shaper
+ */
+struct net_shaper {
+	struct net_shaper_handle parent;
+	struct net_shaper_handle handle;
+	enum net_shaper_metric metric;
+	u64 bw_min;
+	u64 bw_max;
+	u64 burst;
+	u32 priority;
+	u32 weight;
+
+	/* private: */
+	u32 leaves; /* accounted only for NODE scope */
+	struct rcu_head rcu;
+};
+
+/**
+ * struct net_shaper_ops - Operations on device H/W shapers
+ *
+ * The operations applies to either net_device and devlink objects.
+ * The initial shaping configuration at device initialization is empty:
+ * does not constraint the rate in any way.
+ * The network core keeps track of the applied user-configuration in
+ * the net_device or devlink structure.
+ * The operations are serialized via a per device lock.
+ *
+ * Device not supporting any kind of nesting should not provide the
+ * group operation.
+ *
+ * Each shaper is uniquely identified within the device with a 'handle'
+ * comprising the shaper scope and a scope-specific id.
+ */
+struct net_shaper_ops {
+	/**
+	 * @group: create the specified shapers scheduling group
+	 *
+	 * Nest the @leaves shapers identified under the * @node shaper.
+	 * All the shapers belong to the device specified by @binding.
+	 * The @leaves arrays size is specified by @leaves_count.
+	 * Create either the @leaves and the @node shaper; or if they already
+	 * exists, links them together in the desired way.
+	 * @leaves scope must be NET_SHAPER_SCOPE_QUEUE.
+	 */
+	int (*group)(struct net_shaper_binding *binding, int leaves_count,
+		     const struct net_shaper *leaves,
+		     const struct net_shaper *node,
+		     struct netlink_ext_ack *extack);
+
+	/**
+	 * @set: Updates the specified shaper
+	 *
+	 * Updates or creates the @shaper on the device specified by @binding.
+	 */
+	int (*set)(struct net_shaper_binding *binding,
+		   const struct net_shaper *shaper,
+		   struct netlink_ext_ack *extack);
+
+	/**
+	 * @delete: Removes the specified shaper
+	 *
+	 * Removes the shaper configuration as identified by the given @handle
+	 * on the device specified by @binding, restoring the default behavior.
+	 */
+	int (*delete)(struct net_shaper_binding *binding,
+		      const struct net_shaper_handle *handle,
+		      struct netlink_ext_ack *extack);
+
+	/**
+	 * @capabilities: get the shaper features supported by the device
+	 *
+	 * Fills the bitmask @cap with the supported capabilities for the
+	 * specified @scope and device specified by @binding.
+	 */
+	void (*capabilities)(struct net_shaper_binding *binding,
+			     enum net_shaper_scope scope, unsigned long *cap);
+};
+
+#endif