[PATCH 4/4] uapi/if_ether.h: prevent redefinition of struct ethhdr

From: Hauke Mehrtens
Date: Sun Mar 12 2017 - 18:02:49 EST


From: David Heidelberger <david.heidelberger@xxxxxxx>

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

Signed-off-by: John Spencer <maillist-linux@xxxxxxxxxxx>
Tested-by: David Heidelberger <david.heidelberger@xxxxxxx>
Signed-off-by: Jonas Gorski <jogo@xxxxxxxxxxx>
---
include/uapi/linux/if_ether.h | 3 +++
include/uapi/linux/libc-compat.h | 11 +++++++++++
2 files changed, 14 insertions(+)

diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index 5bc9bfd816b7..fb5ab8c1e753 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -22,6 +22,7 @@
#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
@@ -142,11 +143,13 @@
* 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 ce2fa8a4ced6..c92d32f213d1 100644
--- a/include/uapi/linux/libc-compat.h
+++ b/include/uapi/linux/libc-compat.h
@@ -87,6 +87,14 @@

#endif /* _NET_IF_H */

+/* musl defines the ethhdr struct itself in its netinet/if_ether.h.
+ * Glibc just includes the kernel header and uses a different guard. */
+#if defined(_NETINET_IF_ETHER_H)
+#define __UAPI_DEF_ETHHDR 0
+#else
+#define __UAPI_DEF_ETHHDR 1
+#endif
+
/* Coordinate with glibc netinet/in.h header. */
#if defined(_NETINET_IN_H)

@@ -182,6 +190,9 @@
/* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1

+/* Definitions for if_ether.h */
+#define __UAPI_DEF_ETHHDR 1
+
/* Definitions for in.h */
#define __UAPI_DEF_IN_ADDR 1
#define __UAPI_DEF_IN_IPPROTO 1
--
2.11.0