30ad688094
Make bpf_endian.h compatible with vmlinux.h. It is a frequent request from users wanting to use bpf_endian.h in their BPF applications using CO-RE and vmlinux.h. To achieve that, re-implement byte swap macros and drop all the header includes. This way it can be used both with linux header includes, as well as with a vmlinux.h. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200630152125.3631920-2-andriin@fb.com
100 lines
3.7 KiB
C
100 lines
3.7 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
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#ifndef __BPF_ENDIAN__
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#define __BPF_ENDIAN__
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/*
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* Isolate byte #n and put it into byte #m, for __u##b type.
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* E.g., moving byte #6 (nnnnnnnn) into byte #1 (mmmmmmmm) for __u64:
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* 1) xxxxxxxx nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx
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* 2) nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx 00000000
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* 3) 00000000 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn
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* 4) 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn 00000000
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*/
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#define ___bpf_mvb(x, b, n, m) ((__u##b)(x) << (b-(n+1)*8) >> (b-8) << (m*8))
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#define ___bpf_swab16(x) ((__u16)( \
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___bpf_mvb(x, 16, 0, 1) | \
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___bpf_mvb(x, 16, 1, 0)))
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#define ___bpf_swab32(x) ((__u32)( \
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___bpf_mvb(x, 32, 0, 3) | \
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___bpf_mvb(x, 32, 1, 2) | \
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___bpf_mvb(x, 32, 2, 1) | \
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___bpf_mvb(x, 32, 3, 0)))
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#define ___bpf_swab64(x) ((__u64)( \
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___bpf_mvb(x, 64, 0, 7) | \
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___bpf_mvb(x, 64, 1, 6) | \
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___bpf_mvb(x, 64, 2, 5) | \
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___bpf_mvb(x, 64, 3, 4) | \
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___bpf_mvb(x, 64, 4, 3) | \
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___bpf_mvb(x, 64, 5, 2) | \
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___bpf_mvb(x, 64, 6, 1) | \
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___bpf_mvb(x, 64, 7, 0)))
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/* LLVM's BPF target selects the endianness of the CPU
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* it compiles on, or the user specifies (bpfel/bpfeb),
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* respectively. The used __BYTE_ORDER__ is defined by
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* the compiler, we cannot rely on __BYTE_ORDER from
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* libc headers, since it doesn't reflect the actual
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* requested byte order.
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*
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* Note, LLVM's BPF target has different __builtin_bswapX()
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* semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE
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* in bpfel and bpfeb case, which means below, that we map
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* to cpu_to_be16(). We could use it unconditionally in BPF
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* case, but better not rely on it, so that this header here
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* can be used from application and BPF program side, which
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* use different targets.
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*/
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#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
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# define __bpf_ntohs(x) __builtin_bswap16(x)
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# define __bpf_htons(x) __builtin_bswap16(x)
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# define __bpf_constant_ntohs(x) ___bpf_swab16(x)
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# define __bpf_constant_htons(x) ___bpf_swab16(x)
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# define __bpf_ntohl(x) __builtin_bswap32(x)
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# define __bpf_htonl(x) __builtin_bswap32(x)
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# define __bpf_constant_ntohl(x) ___bpf_swab32(x)
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# define __bpf_constant_htonl(x) ___bpf_swab32(x)
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# define __bpf_be64_to_cpu(x) __builtin_bswap64(x)
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# define __bpf_cpu_to_be64(x) __builtin_bswap64(x)
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# define __bpf_constant_be64_to_cpu(x) ___bpf_swab64(x)
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# define __bpf_constant_cpu_to_be64(x) ___bpf_swab64(x)
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#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
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# define __bpf_ntohs(x) (x)
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# define __bpf_htons(x) (x)
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# define __bpf_constant_ntohs(x) (x)
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# define __bpf_constant_htons(x) (x)
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# define __bpf_ntohl(x) (x)
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# define __bpf_htonl(x) (x)
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# define __bpf_constant_ntohl(x) (x)
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# define __bpf_constant_htonl(x) (x)
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# define __bpf_be64_to_cpu(x) (x)
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# define __bpf_cpu_to_be64(x) (x)
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# define __bpf_constant_be64_to_cpu(x) (x)
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# define __bpf_constant_cpu_to_be64(x) (x)
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#else
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# error "Fix your compiler's __BYTE_ORDER__?!"
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#endif
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#define bpf_htons(x) \
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(__builtin_constant_p(x) ? \
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__bpf_constant_htons(x) : __bpf_htons(x))
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#define bpf_ntohs(x) \
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(__builtin_constant_p(x) ? \
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__bpf_constant_ntohs(x) : __bpf_ntohs(x))
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#define bpf_htonl(x) \
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(__builtin_constant_p(x) ? \
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__bpf_constant_htonl(x) : __bpf_htonl(x))
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#define bpf_ntohl(x) \
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(__builtin_constant_p(x) ? \
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__bpf_constant_ntohl(x) : __bpf_ntohl(x))
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#define bpf_cpu_to_be64(x) \
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(__builtin_constant_p(x) ? \
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__bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
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#define bpf_be64_to_cpu(x) \
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(__builtin_constant_p(x) ? \
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__bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))
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#endif /* __BPF_ENDIAN__ */
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