@@ -2,8 +2,35 @@
#ifndef __BPF_ENDIAN__
#define __BPF_ENDIAN__
-#include <linux/stddef.h>
-#include <linux/swab.h>
+/*
+ * Isolate byte #n and put it into byte #m, for __u##b type.
+ * E.g., moving byte #6 (nnnnnnnn) into byte #1 (mmmmmmmm) for __u64:
+ * 1) xxxxxxxx nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx
+ * 2) nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx 00000000
+ * 3) 00000000 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn
+ * 4) 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn 00000000
+ */
+#define ___bpf_mvb(x, b, n, m) ((__u##b)(x) << (b-(n+1)*8) >> (b-8) << (m*8))
+
+#define ___bpf_swab16(x) ((__u16)( \
+ ___bpf_mvb(x, 16, 0, 1) | \
+ ___bpf_mvb(x, 16, 1, 0)))
+
+#define ___bpf_swab32(x) ((__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)))
+
+#define ___bpf_swab64(x) ((__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) | \
+ ___bpf_mvb(x, 64, 4, 3) | \
+ ___bpf_mvb(x, 64, 5, 2) | \
+ ___bpf_mvb(x, 64, 6, 1) | \
+ ___bpf_mvb(x, 64, 7, 0)))
/* LLVM's BPF target selects the endianness of the CPU
* it compiles on, or the user specifies (bpfel/bpfeb),
@@ -23,16 +50,16 @@
#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_constant_ntohs(x) ___bpf_swab16(x)
+# define __bpf_constant_htons(x) ___bpf_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_constant_ntohl(x) ___bpf_swab32(x)
+# define __bpf_constant_htonl(x) ___bpf_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)
+# define __bpf_constant_be64_to_cpu(x) ___bpf_swab64(x)
+# define __bpf_constant_cpu_to_be64(x) ___bpf_swab64(x)
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
# define __bpf_ntohs(x) (x)
# define __bpf_htons(x) (x)
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> --- tools/lib/bpf/bpf_endian.h | 43 +++++++++++++++++++++++++++++++------- 1 file changed, 35 insertions(+), 8 deletions(-)