eBPF for Windows
•All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Pages
bpf_endian.h
Go to the documentation of this file.
1// Copyright (c) eBPF for Windows contributors
2// SPDX-License-Identifier: MIT
3#pragma once
4
5#include <stdint.h>
6
7// copied from linux kernel v6.1 tools/lib/bpf/bpf_endian.h
8// https://github.com/torvalds/linux/blob/v6.1/tools/lib/bpf/bpf_endian.h
9// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
10
11/*
12 * Isolate byte #n and put it into byte #m, for __u##b type.
13 * E.g., moving byte #6 (nnnnnnnn) into byte #1 (mmmmmmmm) for __u64:
14 * 1) xxxxxxxx nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx
15 * 2) nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx 00000000
16 * 3) 00000000 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn
17 * 4) 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn 00000000
18 */
19
20#define ___bpf_mvb(x, b, n, m) ((__u##b)(x) << (b - (n + 1) * 8) >> (b - 8) << (m * 8))
21
22#define ___bpf_swab16(x) ((__u16)(___bpf_mvb(x, 16, 0, 1) | ___bpf_mvb(x, 16, 1, 0)))
23
24#define ___bpf_swab32(x) \
25 ((__u32)(___bpf_mvb(x, 32, 0, 3) | ___bpf_mvb(x, 32, 1, 2) | ___bpf_mvb(x, 32, 2, 1) | ___bpf_mvb(x, 32, 3, 0)))
26
27#define ___bpf_swab64(x) \
28 ((__u64)(___bpf_mvb(x, 64, 0, 7) | ___bpf_mvb(x, 64, 1, 6) | ___bpf_mvb(x, 64, 2, 5) | ___bpf_mvb(x, 64, 3, 4) | \
29 ___bpf_mvb(x, 64, 4, 3) | ___bpf_mvb(x, 64, 5, 2) | ___bpf_mvb(x, 64, 6, 1) | ___bpf_mvb(x, 64, 7, 0)))
30
31/* LLVM's BPF target selects the endianness of the CPU
32 * it compiles on, or the user specifies (bpfel/bpfeb),
33 * respectively. The used __BYTE_ORDER__ is defined by
34 * the compiler, we cannot rely on __BYTE_ORDER from
35 * libc headers, since it doesn't reflect the actual
36 * requested byte order.
37 *
38 * Note, LLVM's BPF target has different __builtin_bswapX()
39 * semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE
40 * in bpfel and bpfeb case, which means below, that we map
41 * to cpu_to_be16(). We could use it unconditionally in BPF
42 * case, but better not rely on it, so that this header here
43 * can be used from application and BPF program side, which
44 * use different targets.
45 */
46#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
47#define __bpf_ntohs(x) __builtin_bswap16(x)
48#define __bpf_htons(x) __builtin_bswap16(x)
49#define __bpf_constant_ntohs(x) ___bpf_swab16(x)
50#define __bpf_constant_htons(x) ___bpf_swab16(x)
51#define __bpf_ntohl(x) __builtin_bswap32(x)
52#define __bpf_htonl(x) __builtin_bswap32(x)
53#define __bpf_constant_ntohl(x) ___bpf_swab32(x)
54#define __bpf_constant_htonl(x) ___bpf_swab32(x)
55#define __bpf_be64_to_cpu(x) __builtin_bswap64(x)
56#define __bpf_cpu_to_be64(x) __builtin_bswap64(x)
57#define __bpf_constant_be64_to_cpu(x) ___bpf_swab64(x)
58#define __bpf_constant_cpu_to_be64(x) ___bpf_swab64(x)
59#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
60#define __bpf_ntohs(x) (x)
61#define __bpf_htons(x) (x)
62#define __bpf_constant_ntohs(x) (x)
63#define __bpf_constant_htons(x) (x)
64#define __bpf_ntohl(x) (x)
65#define __bpf_htonl(x) (x)
66#define __bpf_constant_ntohl(x) (x)
67#define __bpf_constant_htonl(x) (x)
68#define __bpf_be64_to_cpu(x) (x)
69#define __bpf_cpu_to_be64(x) (x)
70#define __bpf_constant_be64_to_cpu(x) (x)
71#define __bpf_constant_cpu_to_be64(x) (x)
72#else
73#error "Fix your compiler's __BYTE_ORDER__?!"
74#endif
75
76#define bpf_htons(x) (__builtin_constant_p(x) ? __bpf_constant_htons(x) : __bpf_htons(x))
77#define bpf_ntohs(x) (__builtin_constant_p(x) ? __bpf_constant_ntohs(x) : __bpf_ntohs(x))
78#define bpf_htonl(x) (__builtin_constant_p(x) ? __bpf_constant_htonl(x) : __bpf_htonl(x))
79#define bpf_ntohl(x) (__builtin_constant_p(x) ? __bpf_constant_ntohl(x) : __bpf_ntohl(x))
80#define bpf_cpu_to_be64(x) (__builtin_constant_p(x) ? __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
81#define bpf_be64_to_cpu(x) (__builtin_constant_p(x) ? __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))
82
83#ifndef ntohs
84#define ntohs bpf_ntohs
85#endif
86#ifndef htons
87#define htons bpf_htons
88#endif
89
90#ifndef ntohl
91#define ntohl bpf_ntohl
92#endif
93#ifndef htonl
94#define htonl bpf_htonl
95#endif
Generated by doxygen 1.9.8