[PATCH 0/1] rtnetlink/netdevice include triggers userspace compiler errors

[PATCH 0/1] rtnetlink/netdevice include triggers userspace compiler errors

[Andy Whitcroft]

We have seen a number of reports of userspace applications (including
eglibc) which fail to compile when trying to use linux/rtnetlink.h.
It appears that a new helper function has necessitated the inclusion of
linux/netdevice.h which in turn causes a collision with userspace headers
from libc, with net/if.h.

It appears that this header is not required for the userspace exported
components of rtnetlink.h.  Following this email is a patch to pull this
include down in the the kernel specific section of this header.  It seems
to both fix this issue for userspace and still compiles correctly for
kernel use.

Against v2.6.37-rc1.

-apw

Andy Whitcroft (1):
  net: rtnetlink.h -- only include linux/netdevice.h when used by the
    kernel

 include/linux/rtnetlink.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

[PATCH 1/1] net: rtnetlink.h -- only include linux/netdevice.h when used by the kernel

[Andy Whitcroft]

The commit below added a new helper dev_ingress_queue to cleanly obtain the
ingress queue pointer.  This necessitated including 'linux/netdevice.h':

  commit 24824a09e35402b8d58dcc5be803a5ad3937bdba
  Author: Eric Dumazet <eric.dumazet@gmail.com>
  Date:   Sat Oct 2 06:11:55 2010 +0000

    net: dynamic ingress_queue allocation

However this include triggers issues for applications in userspace
which use the rtnetlink interfaces.  Commonly this requires they include
'net/if.h' and 'linux/rtnetlink.h' leading to a compiler error as below:

  In file included from /usr/include/linux/netdevice.h:28:0,
                   from /usr/include/linux/rtnetlink.h:9,
                   from t.c:2:
  /usr/include/linux/if.h:135:8: error: redefinition of ‘struct ifmap’
  /usr/include/net/if.h:112:8: note: originally defined here
  /usr/include/linux/if.h:169:8: error: redefinition of ‘struct ifreq’
  /usr/include/net/if.h:127:8: note: originally defined here
  /usr/include/linux/if.h:218:8: error: redefinition of ‘struct ifconf’
  /usr/include/net/if.h:177:8: note: originally defined here

The new helper is only defined for the kernel and protected by __KERNEL__
therefore we can simply pull the include down into the same protected
section.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
---
 include/linux/rtnetlink.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index d42f274..bbad657 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -6,7 +6,6 @@
 #include <linux/if_link.h>
 #include <linux/if_addr.h>
 #include <linux/neighbour.h>
-#include <linux/netdevice.h>
 
 /* rtnetlink families. Values up to 127 are reserved for real address
  * families, values above 128 may be used arbitrarily.
@@ -606,6 +605,7 @@ struct tcamsg {
 #ifdef __KERNEL__
 
 #include <linux/mutex.h>
+#include <linux/netdevice.h>
 
 static __inline__ int rtattr_strcmp(const struct rtattr *rta, const char *str)
 {
-- 
1.7.0.4

Re: [PATCH 1/1] net: rtnetlink.h -- only include linux/netdevice.h when used by the kernel

[David Miller]

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From: Andy Whitcroft <apw@canonical.com>
Date: Mon, 15 Nov 2010 16:01:59 +0000

> The commit below added a new helper dev_ingress_queue to cleanly obtain the
> ingress queue pointer.  This necessitated including 'linux/netdevice.h':
 ...
> However this include triggers issues for applications in userspace
> which use the rtnetlink interfaces.  Commonly this requires they include
> 'net/if.h' and 'linux/rtnetlink.h' leading to a compiler error as below:
> 
>   In file included from /usr/include/linux/netdevice.h:28:0,
>                    from /usr/include/linux/rtnetlink.h:9,
>                    from t.c:2:
>   /usr/include/linux/if.h:135:8: error: redefinition of ¡struct ifmap¢
>   /usr/include/net/if.h:112:8: note: originally defined here
>   /usr/include/linux/if.h:169:8: error: redefinition of ¡struct ifreq¢
>   /usr/include/net/if.h:127:8: note: originally defined here
>   /usr/include/linux/if.h:218:8: error: redefinition of ¡struct ifconf¢
>   /usr/include/net/if.h:177:8: note: originally defined here
> 
> The new helper is only defined for the kernel and protected by __KERNEL__
> therefore we can simply pull the include down into the same protected
> section.
> 
> Signed-off-by: Andy Whitcroft <apw@canonical.com>

Applied, thanks Andy.
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