net: Make userland include of netlink.h more sane.
authorDavid S. Miller <davem@davemloft.net>
Mon, 8 Aug 2011 05:48:07 +0000 (22:48 -0700)
committerDavid S. Miller <davem@davemloft.net>
Mon, 8 Aug 2011 05:48:07 +0000 (22:48 -0700)
commit6602a4baf4d1a73cc4685a39ef859e1c5ddf654c
treed25eac2abeb52608af77e55b1acd56c8904aecea
parentdd23198e58cd35259dd09e8892bbdb90f1d57748
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>
include/linux/netlink.h
include/linux/socket.h