net: Make userland include of netlink.h more sane.

Currently userland will barf when including linux/netlink.h unless it
precisely includes sys/socket.h first.  The issue is where the
definition of "sa_family_t" comes from.

We've been back and forth on how to fix this issue in the past, see:

http://thread.gmane.org/gmane.linux.debian.devel.bugs.general/622621
http://thread.gmane.org/gmane.linux.network/143380

Ben Hutchings suggested we take a hint from how we handle the
sockaddr_storage type.  First we define a "__kernel_sa_family_t"
to linux/socket.h that is always defined.

Then if __KERNEL__ is defined, we also define "sa_family_t" as
equal to "__kernel_sa_family_t".

Then in places like linux/netlink.h we use __kernel_sa_family_t
in user visible datastructures.

Reported-by: Michel Machado <michel@digirati.com.br>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 2e17c5dbdcb8..180540a84d37 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -29,7 +29,7 @@
 #define MAX_LINKS 32            
 
 struct sockaddr_nl {
-        sa_family_t     nl_family;      /* AF_NETLINK   */
+        __kernel_sa_family_t    nl_family;      /* AF_NETLINK   */
         unsigned short  nl_pad;         /* zero         */
         __u32           nl_pid;         /* port ID      */
         __u32           nl_groups;      /* multicast groups mask */