kernel: improve uapi headers coexistence with musl

Make some network uapi headers detect if they are included after
not only glibc but also musl headers.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>

SVN-Revision: 46161

1 files changed, 67 insertions, 0 deletions

diff --git a/target/linux/generic/patches-4.1/272-uapi-if_ether.h-prevent-redefinition-of-struct-ethhd.patch b/target/linux/generic/patches-4.1/272-uapi-if_ether.h-prevent-redefinition-of-struct-ethhd.patch
new file mode 100644
index 0000000000..257c9d7e99
--- /dev/null
+++ b/target/linux/generic/patches-4.1/272-uapi-if_ether.h-prevent-redefinition-of-struct-ethhd.patch
@@ -0,0 +1,67 @@
+From fcbb6fed85ea9ff4feb4f1ebd4f0f235fdaf06b6 Mon Sep 17 00:00:00 2001
+From: David Heidelberger <david.heidelberger@ixit.cz>
+Date: Mon, 29 Jun 2015 16:53:03 +0200
+Subject: [PATCH 3/3] 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.
+
+Signed-off-by: John Spencer <maillist-linux@barfooze.de>
+Tested-by: David Heidelberger <david.heidelberger@ixit.cz>
+Signed-off-by: Jonas Gorski <jogo@openwrt.org>
+---
+ include/uapi/linux/if_ether.h    |  3 +++
+ include/uapi/linux/libc-compat.h | 11 +++++++++++
+ 2 files changed, 14 insertions(+)
+
+--- 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
+@@ -134,11 +135,13 @@
+  *	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 */
+--- a/include/uapi/linux/libc-compat.h
++++ b/include/uapi/linux/libc-compat.h
+@@ -51,6 +51,14 @@
+ /* We have included libc headers... */
+ #if !defined(__KERNEL__)
+ 
++/* 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 libc netinet/in.h header. */
+ #if defined(_NETINET_IN_H)
+ 
+@@ -117,6 +125,9 @@
+  * that we need. */
+ #else /* defined(__KERNEL__) */
+ 
++/* 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