1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
 2#ifndef __BPF_ENDIAN__
 3#define __BPF_ENDIAN__
 4
 5/*
 6 * Isolate byte #n and put it into byte #m, for __u##b type.
 7 * E.g., moving byte #6 (nnnnnnnn) into byte #1 (mmmmmmmm) for __u64:
 8 * 1) xxxxxxxx nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx
 9 * 2) nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx 00000000
10 * 3) 00000000 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn
11 * 4) 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn 00000000
12 */
13#define ___bpf_mvb(x, b, n, m) ((__u##b)(x) << (b-(n+1)*8) >> (b-8) << (m*8))
14
15#define ___bpf_swab16(x) ((__u16)(			\
16			  ___bpf_mvb(x, 16, 0, 1) |	\
17			  ___bpf_mvb(x, 16, 1, 0)))
18
19#define ___bpf_swab32(x) ((__u32)(			\
20			  ___bpf_mvb(x, 32, 0, 3) |	\
21			  ___bpf_mvb(x, 32, 1, 2) |	\
22			  ___bpf_mvb(x, 32, 2, 1) |	\
23			  ___bpf_mvb(x, 32, 3, 0)))
24
25#define ___bpf_swab64(x) ((__u64)(			\
26			  ___bpf_mvb(x, 64, 0, 7) |	\
27			  ___bpf_mvb(x, 64, 1, 6) |	\
28			  ___bpf_mvb(x, 64, 2, 5) |	\
29			  ___bpf_mvb(x, 64, 3, 4) |	\
30			  ___bpf_mvb(x, 64, 4, 3) |	\
31			  ___bpf_mvb(x, 64, 5, 2) |	\
32			  ___bpf_mvb(x, 64, 6, 1) |	\
33			  ___bpf_mvb(x, 64, 7, 0)))
34
35/* LLVM's BPF target selects the endianness of the CPU
36 * it compiles on, or the user specifies (bpfel/bpfeb),
37 * respectively. The used __BYTE_ORDER__ is defined by
38 * the compiler, we cannot rely on __BYTE_ORDER from
39 * libc headers, since it doesn't reflect the actual
40 * requested byte order.
41 *
42 * Note, LLVM's BPF target has different __builtin_bswapX()
43 * semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE
44 * in bpfel and bpfeb case, which means below, that we map
45 * to cpu_to_be16(). We could use it unconditionally in BPF
46 * case, but better not rely on it, so that this header here
47 * can be used from application and BPF program side, which
48 * use different targets.
49 */
50#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
51# define __bpf_ntohs(x)			__builtin_bswap16(x)
52# define __bpf_htons(x)			__builtin_bswap16(x)
53# define __bpf_constant_ntohs(x)	___bpf_swab16(x)
54# define __bpf_constant_htons(x)	___bpf_swab16(x)
55# define __bpf_ntohl(x)			__builtin_bswap32(x)
56# define __bpf_htonl(x)			__builtin_bswap32(x)
57# define __bpf_constant_ntohl(x)	___bpf_swab32(x)
58# define __bpf_constant_htonl(x)	___bpf_swab32(x)
59# define __bpf_be64_to_cpu(x)		__builtin_bswap64(x)
60# define __bpf_cpu_to_be64(x)		__builtin_bswap64(x)
61# define __bpf_constant_be64_to_cpu(x)	___bpf_swab64(x)
62# define __bpf_constant_cpu_to_be64(x)	___bpf_swab64(x)
63#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
64# define __bpf_ntohs(x)			(x)
65# define __bpf_htons(x)			(x)
66# define __bpf_constant_ntohs(x)	(x)
67# define __bpf_constant_htons(x)	(x)
68# define __bpf_ntohl(x)			(x)
69# define __bpf_htonl(x)			(x)
70# define __bpf_constant_ntohl(x)	(x)
71# define __bpf_constant_htonl(x)	(x)
72# define __bpf_be64_to_cpu(x)		(x)
73# define __bpf_cpu_to_be64(x)		(x)
74# define __bpf_constant_be64_to_cpu(x)  (x)
75# define __bpf_constant_cpu_to_be64(x)  (x)
76#else
77# error "Fix your compiler's __BYTE_ORDER__?!"
78#endif
79
80#define bpf_htons(x)				\
81	(__builtin_constant_p(x) ?		\
82	 __bpf_constant_htons(x) : __bpf_htons(x))
83#define bpf_ntohs(x)				\
84	(__builtin_constant_p(x) ?		\
85	 __bpf_constant_ntohs(x) : __bpf_ntohs(x))
86#define bpf_htonl(x)				\
87	(__builtin_constant_p(x) ?		\
88	 __bpf_constant_htonl(x) : __bpf_htonl(x))
89#define bpf_ntohl(x)				\
90	(__builtin_constant_p(x) ?		\
91	 __bpf_constant_ntohl(x) : __bpf_ntohl(x))
92#define bpf_cpu_to_be64(x)			\
93	(__builtin_constant_p(x) ?		\
94	 __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
95#define bpf_be64_to_cpu(x)			\
96	(__builtin_constant_p(x) ?		\
97	 __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))
98
99#endif /* __BPF_ENDIAN__ */