Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/tools/lib/bpf/bpf_endian.h
26282 views
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__ */

100


101