linux/samples/bpf/xdp_sample.bpf.h

// SPDX-License-Identifier: GPL-2.0
#ifndef _XDP_SAMPLE_BPF_H
#define _XDP_SAMPLE_BPF_H

#include "vmlinux.h"
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_helpers.h>

#include "net_shared.h"
#include "xdp_sample_shared.h"

#define EINVAL 22
#define ENETDOWN 100
#define EMSGSIZE 90
#define EOPNOTSUPP 95
#define ENOSPC 28

typedef struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(map_flags, BPF_F_MMAPABLE);
	__type(key, unsigned int);
	__type(value, struct datarec);
} array_map;

extern array_map rx_cnt;
extern const volatile int nr_cpus;

enum {
	XDP_REDIRECT_SUCCESS = 0,
	XDP_REDIRECT_ERROR = 1
};

static __always_inline void swap_src_dst_mac(void *data)
{
	unsigned short *p = data;
	unsigned short dst[3];

	dst[0] = p[0];
	dst[1] = p[1];
	dst[2] = p[2];
	p[0] = p[3];
	p[1] = p[4];
	p[2] = p[5];
	p[3] = dst[0];
	p[4] = dst[1];
	p[5] = dst[2];
}

/*
 * Note: including linux/compiler.h or linux/kernel.h for the macros below
 * conflicts with vmlinux.h include in BPF files, so we define them here.
 *
 * Following functions are taken from kernel sources and
 * break aliasing rules in their original form.
 *
 * While kernel is compiled with -fno-strict-aliasing,
 * perf uses -Wstrict-aliasing=3 which makes build fail
 * under gcc 4.4.
 *
 * Using extra __may_alias__ type to allow aliasing
 * in this case.
 */
typedef __u8  __attribute__((__may_alias__))  __u8_alias_t;
typedef __u16 __attribute__((__may_alias__)) __u16_alias_t;
typedef __u32 __attribute__((__may_alias__)) __u32_alias_t;
typedef __u64 __attribute__((__may_alias__)) __u64_alias_t;

static __always_inline void __read_once_size(const volatile void *p, void *res, int size)
{
	switch (size) {
	case 1: *(__u8_alias_t  *) res = *(volatile __u8_alias_t  *) p; break;
	case 2: *(__u16_alias_t *) res = *(volatile __u16_alias_t *) p; break;
	case 4: *(__u32_alias_t *) res = *(volatile __u32_alias_t *) p; break;
	case 8: *(__u64_alias_t *) res = *(volatile __u64_alias_t *) p; break;
	default:
		asm volatile ("" : : : "memory");
		__builtin_memcpy((void *)res, (const void *)p, size);
		asm volatile ("" : : : "memory");
	}
}

static __always_inline void __write_once_size(volatile void *p, void *res, int size)
{
	switch (size) {
	case 1: *(volatile  __u8_alias_t *) p = *(__u8_alias_t  *) res; break;
	case 2: *(volatile __u16_alias_t *) p = *(__u16_alias_t *) res; break;
	case 4: *(volatile __u32_alias_t *) p = *(__u32_alias_t *) res; break;
	case 8: *(volatile __u64_alias_t *) p = *(__u64_alias_t *) res; break;
	default:
		asm volatile ("" : : : "memory");
		__builtin_memcpy((void *)p, (const void *)res, size);
		asm volatile ("" : : : "memory");
	}
}

#define READ_ONCE(x)					\
({							\
	union { typeof(x) __val; char __c[1]; } __u =	\
		{ .__c = { 0 } };			\
	__read_once_size(&(x), __u.__c, sizeof(x));	\
	__u.__val;					\
})

#define WRITE_ONCE(x, val)				\
({							\
	union { typeof(x) __val; char __c[1]; } __u =	\
		{ .__val = (val) }; 			\
	__write_once_size(&(x), __u.__c, sizeof(x));	\
	__u.__val;					\
})

/* Add a value using relaxed read and relaxed write. Less expensive than
 * fetch_add when there is no write concurrency.
 */
#define NO_TEAR_ADD(x, val) WRITE_ONCE((x), READ_ONCE(x) + (val))
#define NO_TEAR_INC(x) NO_TEAR_ADD((x), 1)

#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

#endif