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-rw-r--r--tools/lib/bpf/bpf_endian.h72
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diff --git a/tools/lib/bpf/bpf_endian.h b/tools/lib/bpf/bpf_endian.h
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+++ b/tools/lib/bpf/bpf_endian.h
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+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __BPF_ENDIAN__
+#define __BPF_ENDIAN__
+
+#include <linux/stddef.h>
+#include <linux/swab.h>
+
+/* LLVM's BPF target selects the endianness of the CPU
+ * it compiles on, or the user specifies (bpfel/bpfeb),
+ * respectively. The used __BYTE_ORDER__ is defined by
+ * the compiler, we cannot rely on __BYTE_ORDER from
+ * libc headers, since it doesn't reflect the actual
+ * requested byte order.
+ *
+ * Note, LLVM's BPF target has different __builtin_bswapX()
+ * semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE
+ * in bpfel and bpfeb case, which means below, that we map
+ * to cpu_to_be16(). We could use it unconditionally in BPF
+ * case, but better not rely on it, so that this header here
+ * can be used from application and BPF program side, which
+ * use different targets.
+ */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define __bpf_ntohs(x) __builtin_bswap16(x)
+# define __bpf_htons(x) __builtin_bswap16(x)
+# define __bpf_constant_ntohs(x) ___constant_swab16(x)
+# define __bpf_constant_htons(x) ___constant_swab16(x)
+# define __bpf_ntohl(x) __builtin_bswap32(x)
+# define __bpf_htonl(x) __builtin_bswap32(x)
+# define __bpf_constant_ntohl(x) ___constant_swab32(x)
+# define __bpf_constant_htonl(x) ___constant_swab32(x)
+# define __bpf_be64_to_cpu(x) __builtin_bswap64(x)
+# define __bpf_cpu_to_be64(x) __builtin_bswap64(x)
+# define __bpf_constant_be64_to_cpu(x) ___constant_swab64(x)
+# define __bpf_constant_cpu_to_be64(x) ___constant_swab64(x)
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define __bpf_ntohs(x) (x)
+# define __bpf_htons(x) (x)
+# define __bpf_constant_ntohs(x) (x)
+# define __bpf_constant_htons(x) (x)
+# define __bpf_ntohl(x) (x)
+# define __bpf_htonl(x) (x)
+# define __bpf_constant_ntohl(x) (x)
+# define __bpf_constant_htonl(x) (x)
+# define __bpf_be64_to_cpu(x) (x)
+# define __bpf_cpu_to_be64(x) (x)
+# define __bpf_constant_be64_to_cpu(x) (x)
+# define __bpf_constant_cpu_to_be64(x) (x)
+#else
+# error "Fix your compiler's __BYTE_ORDER__?!"
+#endif
+
+#define bpf_htons(x) \
+ (__builtin_constant_p(x) ? \
+ __bpf_constant_htons(x) : __bpf_htons(x))
+#define bpf_ntohs(x) \
+ (__builtin_constant_p(x) ? \
+ __bpf_constant_ntohs(x) : __bpf_ntohs(x))
+#define bpf_htonl(x) \
+ (__builtin_constant_p(x) ? \
+ __bpf_constant_htonl(x) : __bpf_htonl(x))
+#define bpf_ntohl(x) \
+ (__builtin_constant_p(x) ? \
+ __bpf_constant_ntohl(x) : __bpf_ntohl(x))
+#define bpf_cpu_to_be64(x) \
+ (__builtin_constant_p(x) ? \
+ __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
+#define bpf_be64_to_cpu(x) \
+ (__builtin_constant_p(x) ? \
+ __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))
+
+#endif /* __BPF_ENDIAN__ */