LXR linux/tools/lib/bpf/bpf

   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