xref: /openbmc/linux/tools/lib/bpf/bpf_endian.h (revision f9834f18)
1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 #ifndef __BPF_ENDIAN__
3 #define __BPF_ENDIAN__
4 
5 #include <linux/stddef.h>
6 #include <linux/swab.h>
7 
8 /* LLVM's BPF target selects the endianness of the CPU
9  * it compiles on, or the user specifies (bpfel/bpfeb),
10  * respectively. The used __BYTE_ORDER__ is defined by
11  * the compiler, we cannot rely on __BYTE_ORDER from
12  * libc headers, since it doesn't reflect the actual
13  * requested byte order.
14  *
15  * Note, LLVM's BPF target has different __builtin_bswapX()
16  * semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE
17  * in bpfel and bpfeb case, which means below, that we map
18  * to cpu_to_be16(). We could use it unconditionally in BPF
19  * case, but better not rely on it, so that this header here
20  * can be used from application and BPF program side, which
21  * use different targets.
22  */
23 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
24 # define __bpf_ntohs(x)			__builtin_bswap16(x)
25 # define __bpf_htons(x)			__builtin_bswap16(x)
26 # define __bpf_constant_ntohs(x)	___constant_swab16(x)
27 # define __bpf_constant_htons(x)	___constant_swab16(x)
28 # define __bpf_ntohl(x)			__builtin_bswap32(x)
29 # define __bpf_htonl(x)			__builtin_bswap32(x)
30 # define __bpf_constant_ntohl(x)	___constant_swab32(x)
31 # define __bpf_constant_htonl(x)	___constant_swab32(x)
32 # define __bpf_be64_to_cpu(x)		__builtin_bswap64(x)
33 # define __bpf_cpu_to_be64(x)		__builtin_bswap64(x)
34 # define __bpf_constant_be64_to_cpu(x)	___constant_swab64(x)
35 # define __bpf_constant_cpu_to_be64(x)	___constant_swab64(x)
36 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
37 # define __bpf_ntohs(x)			(x)
38 # define __bpf_htons(x)			(x)
39 # define __bpf_constant_ntohs(x)	(x)
40 # define __bpf_constant_htons(x)	(x)
41 # define __bpf_ntohl(x)			(x)
42 # define __bpf_htonl(x)			(x)
43 # define __bpf_constant_ntohl(x)	(x)
44 # define __bpf_constant_htonl(x)	(x)
45 # define __bpf_be64_to_cpu(x)		(x)
46 # define __bpf_cpu_to_be64(x)		(x)
47 # define __bpf_constant_be64_to_cpu(x)  (x)
48 # define __bpf_constant_cpu_to_be64(x)  (x)
49 #else
50 # error "Fix your compiler's __BYTE_ORDER__?!"
51 #endif
52 
53 #define bpf_htons(x)				\
54 	(__builtin_constant_p(x) ?		\
55 	 __bpf_constant_htons(x) : __bpf_htons(x))
56 #define bpf_ntohs(x)				\
57 	(__builtin_constant_p(x) ?		\
58 	 __bpf_constant_ntohs(x) : __bpf_ntohs(x))
59 #define bpf_htonl(x)				\
60 	(__builtin_constant_p(x) ?		\
61 	 __bpf_constant_htonl(x) : __bpf_htonl(x))
62 #define bpf_ntohl(x)				\
63 	(__builtin_constant_p(x) ?		\
64 	 __bpf_constant_ntohl(x) : __bpf_ntohl(x))
65 #define bpf_cpu_to_be64(x)			\
66 	(__builtin_constant_p(x) ?		\
67 	 __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
68 #define bpf_be64_to_cpu(x)			\
69 	(__builtin_constant_p(x) ?		\
70 	 __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))
71 
72 #endif /* __BPF_ENDIAN__ */
73