/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
/* Copyright Authors of Cilium */

#ifndef __LIB_ENDIAN_H_
#define __LIB_ENDIAN_H_

#include <bpf/ctx/ctx.h>
#include <bpf/api.h>

#define ___bpf_mvb(x, b, n, m) ((__u##b)(x) << (b-(n+1)*8) >> (b-8) << (m*8))

#define ___bpf_swab16(x) ((__u16)(			\
			  ___bpf_mvb(x, 16, 0, 1) |	\
			  ___bpf_mvb(x, 16, 1, 0)))

#define ___bpf_swab32(x) ((__u32)(			\
			  ___bpf_mvb(x, 32, 0, 3) |	\
			  ___bpf_mvb(x, 32, 1, 2) |	\
			  ___bpf_mvb(x, 32, 2, 1) |	\
			  ___bpf_mvb(x, 32, 3, 0)))

#define ___bpf_swab64(x) ((__u64)(			\
			  ___bpf_mvb(x, 64, 0, 7) |	\
			  ___bpf_mvb(x, 64, 1, 6) |	\
			  ___bpf_mvb(x, 64, 2, 5) |	\
			  ___bpf_mvb(x, 64, 3, 4) |	\
			  ___bpf_mvb(x, 64, 4, 3) |	\
			  ___bpf_mvb(x, 64, 5, 2) |	\
			  ___bpf_mvb(x, 64, 6, 1) |	\
			  ___bpf_mvb(x, 64, 7, 0)))

#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
# define __bpf_ntohs(x)			__builtin_bswap16(x)
# define __bpf_htons(x)			__builtin_bswap16(x)
# define __bpf_constant_ntohs(x)	___bpf_swab16(x)
# define __bpf_constant_htons(x)	___bpf_swab16(x)
# define __bpf_ntohl(x)			__builtin_bswap32(x)
# define __bpf_htonl(x)			__builtin_bswap32(x)
# define __bpf_constant_ntohl(x)	___bpf_swab32(x)
# define __bpf_constant_htonl(x)	___bpf_swab32(x)
# define __bpf_be64_to_cpu(x)		__builtin_bswap64(x)
# define __bpf_cpu_to_be64(x)		__builtin_bswap64(x)
# define __bpf_constant_be64_to_cpu(x)	___bpf_swab64(x)
# define __bpf_constant_cpu_to_be64(x)	___bpf_swab64(x)
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
# define __bpf_ntohs(x)			(x)
# define __bpf_htons(x)			(x)
# define __bpf_constant_ntohs(x)	(x)
# define __bpf_constant_htons(x)	(x)
# define __bpf_ntohl(x)			(x)
# define __bpf_htonl(x)			(x)
# define __bpf_constant_ntohl(x)	(x)
# define __bpf_constant_htonl(x)	(x)
# define __bpf_be64_to_cpu(x)		(x)
# define __bpf_cpu_to_be64(x)		(x)
# define __bpf_constant_be64_to_cpu(x)  (x)
# define __bpf_constant_cpu_to_be64(x)  (x)
#else
# error "Fix your compiler's __BYTE_ORDER__?!"
#endif

#define bpf_htons(x)				\
	(__builtin_constant_p(x) ?		\
	 __bpf_constant_htons(x) : __bpf_htons(x))
#define bpf_ntohs(x)				\
	(__builtin_constant_p(x) ?		\
	 __bpf_constant_ntohs(x) : __bpf_ntohs(x))
#define bpf_htonl(x)				\
	(__builtin_constant_p(x) ?		\
	 __bpf_constant_htonl(x) : __bpf_htonl(x))
#define bpf_ntohl(x)				\
	(__builtin_constant_p(x) ?		\
	 __bpf_constant_ntohl(x) : __bpf_ntohl(x))
#define bpf_cpu_to_be64(x)			\
	(__builtin_constant_p(x) ?		\
	 __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
#define bpf_be64_to_cpu(x)			\
	(__builtin_constant_p(x) ?		\
	 __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))

#endif /* __LIB_ENDIAN_H_ */