xdp: T2666: switch to example code provided by xdp-tutorial

1 files changed, 58 insertions, 0 deletions

diff --git a/src/xdp/include/bpf_endian.h b/src/xdp/include/bpf_endian.h
new file mode 100644
index 000000000..2b0ede3d5
--- /dev/null
+++ b/src/xdp/include/bpf_endian.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copied from $(LINUX)/tools/testing/selftests/bpf/bpf_endian.h */
+#ifndef __BPF_ENDIAN__
+#define __BPF_ENDIAN__
+
+#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)
+#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)
+#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))
+
+#endif /* __BPF_ENDIAN__ */