drop_monitor: Add basic infrastructure for hardware drops

Export a function that can be invoked in order to report packets that
were dropped by the underlying hardware along with metadata.

Subsequent patches will add support for the different alert modes.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/drop_monitor.h

@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _NET_DROP_MONITOR_H_
+#define _NET_DROP_MONITOR_H_
+
+#include <linux/ktime.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+
+/**
+ * struct net_dm_hw_metadata - Hardware-supplied packet metadata.
+ * @trap_group_name: Hardware trap group name.
+ * @trap_name: Hardware trap name.
+ * @input_dev: Input netdevice.
+ */
+struct net_dm_hw_metadata {
+	const char *trap_group_name;
+	const char *trap_name;
+	struct net_device *input_dev;
+};
+
+#if IS_ENABLED(CONFIG_NET_DROP_MONITOR)
+void net_dm_hw_report(struct sk_buff *skb,
+		      const struct net_dm_hw_metadata *hw_metadata);
+#else
+static inline void
+net_dm_hw_report(struct sk_buff *skb,
+		 const struct net_dm_hw_metadata *hw_metadata)
+{
+}
+#endif
+
+#endif /* _NET_DROP_MONITOR_H_ */