4 #include <linux/swab.h>
6 /* LLVM's BPF target selects the endianness of the CPU
7 * it compiles on, or the user specifies (bpfel/bpfeb),
8 * respectively. The used __BYTE_ORDER__ is defined by
9 * the compiler, we cannot rely on __BYTE_ORDER from
10 * libc headers, since it doesn't reflect the actual
11 * requested byte order.
13 * Note, LLVM's BPF target has different __builtin_bswapX()
14 * semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE
15 * in bpfel and bpfeb case, which means below, that we map
16 * to cpu_to_be16(). We could use it unconditionally in BPF
17 * case, but better not rely on it, so that this header here
18 * can be used from application and BPF program side, which
19 * use different targets.
21 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
22 # define __bpf_ntohs(x) __builtin_bswap16(x)
23 # define __bpf_htons(x) __builtin_bswap16(x)
24 # define __bpf_constant_ntohs(x) ___constant_swab16(x)
25 # define __bpf_constant_htons(x) ___constant_swab16(x)
26 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
27 # define __bpf_ntohs(x) (x)
28 # define __bpf_htons(x) (x)
29 # define __bpf_constant_ntohs(x) (x)
30 # define __bpf_constant_htons(x) (x)
32 # error "Fix your compiler's __BYTE_ORDER__?!"
35 #define bpf_htons(x) \
36 (__builtin_constant_p(x) ? \
37 __bpf_constant_htons(x) : __bpf_htons(x))
38 #define bpf_ntohs(x) \
39 (__builtin_constant_p(x) ? \
40 __bpf_constant_ntohs(x) : __bpf_ntohs(x))
42 #endif /* __BPF_ENDIAN__ */