uapi/if_ether.h: prevent redefinition of struct ethhdr

Musl provides its own ethhdr struct definition. Add a guard to prevent
its definition of the appropriate musl header has already been included.

glibc does not implement this header, but when glibc will implement this
they can just define __UAPI_DEF_ETHHDR 0 to make it work with the
kernel.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 0 deletions

diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index 3ee3bf7c8526..144de4d2f385 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -23,6 +23,7 @@
 #define _UAPI_LINUX_IF_ETHER_H
 
 #include <linux/types.h>
+#include <linux/libc-compat.h>
 
 /*
  *      IEEE 802.3 Ethernet magic constants.  The frame sizes omit the preamble
@@ -149,11 +150,13 @@
  *      This is an Ethernet frame header.
  */
 
+#if __UAPI_DEF_ETHHDR
 struct ethhdr {
         unsigned char   h_dest[ETH_ALEN];       /* destination eth addr */
         unsigned char   h_source[ETH_ALEN];     /* source ether addr    */
         __be16          h_proto;                /* packet type ID field */
 } __attribute__((packed));
+#endif
 
 
 #endif /* _UAPI_LINUX_IF_ETHER_H */
diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-compat.h
index 8254c937c9f4..fc29efaa918c 100644
--- a/include/uapi/linux/libc-compat.h
+++ b/include/uapi/linux/libc-compat.h
@@ -264,4 +264,10 @@
 
 #endif /* __GLIBC__ */
 
+/* Definitions for if_ether.h */
+/* allow libcs like musl to deactivate this, glibc does not implement this. */
+#ifndef __UAPI_DEF_ETHHDR
+#define __UAPI_DEF_ETHHDR               1
+#endif
+
 #endif /* _UAPI_LIBC_COMPAT_H */