From e69fe8459552f112d7327dff87953d40202c61f1 Mon Sep 17 00:00:00 2001
From: "Daniel T. Lee" <danieltimlee@gmail.com>
Date: Sun, 15 Jan 2023 16:16:10 +0900
Subject: [PATCH] samples/bpf: split common macros to net_shared.h

Currently, many programs under sample/bpf often include individual
macros by directly including the header under "linux/" rather than
using the "vmlinux.h" header.

However, there are some problems with migrating to "vmlinux.h" because
there is no definition for utility functions such as endianness
conversion (ntohs/htons). Fortunately, the xdp_sample program already
has a function that can be replaced to solve this problem.

Therefore, this commit attempts to separate these functions into a file
called net_shared.h to make them universally available. Additionally,
this file includes network-related macros that are not defined in
"vmlinux.h". (inspired by 'selftests' bpf_tracing_net.h)

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230115071613.125791-8-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 samples/bpf/net_shared.h     | 26 ++++++++++++++++++++++++++
 samples/bpf/xdp_sample.bpf.h | 22 +---------------------
 2 files changed, 27 insertions(+), 21 deletions(-)
 create mode 100644 samples/bpf/net_shared.h

diff --git a/samples/bpf/net_shared.h b/samples/bpf/net_shared.h
new file mode 100644
index 000000000000..04b29b217d25
--- /dev/null
+++ b/samples/bpf/net_shared.h
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef _NET_SHARED_H
+#define _NET_SHARED_H
+
+#define ETH_ALEN 6
+#define ETH_P_802_3_MIN 0x0600
+#define ETH_P_8021Q 0x8100
+#define ETH_P_8021AD 0x88A8
+#define ETH_P_IP 0x0800
+#define ETH_P_IPV6 0x86DD
+#define ETH_P_ARP 0x0806
+#define IPPROTO_ICMPV6 58
+
+#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \
+	__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define bpf_ntohs(x)		__builtin_bswap16(x)
+#define bpf_htons(x)		__builtin_bswap16(x)
+#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
+	__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define bpf_ntohs(x)		(x)
+#define bpf_htons(x)		(x)
+#else
+# error "Endianness detection needs to be set up for your compiler?!"
+#endif
+
+#endif
diff --git a/samples/bpf/xdp_sample.bpf.h b/samples/bpf/xdp_sample.bpf.h
index 25b1dbe9b37b..fecc41c5df04 100644
--- a/samples/bpf/xdp_sample.bpf.h
+++ b/samples/bpf/xdp_sample.bpf.h
@@ -7,17 +7,9 @@
 #include <bpf/bpf_core_read.h>
 #include <bpf/bpf_helpers.h>
 
+#include "net_shared.h"
 #include "xdp_sample_shared.h"
 
-#define ETH_ALEN 6
-#define ETH_P_802_3_MIN 0x0600
-#define ETH_P_8021Q 0x8100
-#define ETH_P_8021AD 0x88A8
-#define ETH_P_IP 0x0800
-#define ETH_P_IPV6 0x86DD
-#define ETH_P_ARP 0x0806
-#define IPPROTO_ICMPV6 58
-
 #define EINVAL 22
 #define ENETDOWN 100
 #define EMSGSIZE 90
@@ -55,18 +47,6 @@ static __always_inline void swap_src_dst_mac(void *data)
 	p[5] = dst[2];
 }
 
-#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \
-	__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-#define bpf_ntohs(x)		__builtin_bswap16(x)
-#define bpf_htons(x)		__builtin_bswap16(x)
-#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
-	__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-#define bpf_ntohs(x)		(x)
-#define bpf_htons(x)		(x)
-#else
-# error "Endianness detection needs to be set up for your compiler?!"
-#endif
-
 /*
  * Note: including linux/compiler.h or linux/kernel.h for the macros below
  * conflicts with vmlinux.h include in BPF files, so we define them here.