xdp_stats_kern.h

/* SPDX-License-Identifier: GPL-2.0 */

/* Used *ONLY* by BPF-prog running kernel side. */
#ifndef __XDP_STATS_KERN_H
#define __XDP_STATS_KERN_H

/* Data record type 'struct datarec' is defined in common/xdp_stats_kern_user.h,
 * programs using this header must first include that file.
 */
#ifndef __XDP_STATS_KERN_USER_H
#warning "You forgot to #include <../common/xdp_stats_kern_user.h>"
#include <../common/xdp_stats_kern_user.h>
#endif

/* Keeps stats per (enum) xdp_action */
struct bpf_map_def SEC("maps") xdp_stats_map = {
	.type        = BPF_MAP_TYPE_PERCPU_ARRAY,
	.key_size    = sizeof(__u32),
	.value_size  = sizeof(struct datarec),
	.max_entries = XDP_ACTION_MAX,
};

static __always_inline
__u32 xdp_stats_record_action(struct xdp_md *ctx, __u32 action)
{
	if (action >= XDP_ACTION_MAX)
		return XDP_ABORTED;

	/* Lookup in kernel BPF-side return pointer to actual data record */
	struct datarec *rec = bpf_map_lookup_elem(&xdp_stats_map, &action);
	if (!rec)
		return XDP_ABORTED;

	/* BPF_MAP_TYPE_PERCPU_ARRAY returns a data record specific to current
	 * CPU and XDP hooks runs under Softirq, which makes it safe to update
	 * without atomic operations.
	 */
	rec->rx_packets++;
	rec->rx_bytes += (ctx->data_end - ctx->data);

	return action;
}

#endif /* __XDP_STATS_KERN_H */