Subject: Re: Commit 1fe8e0... (include more headers in if_tunnel.h) breaks my user-space build.

From: Stephen Hemminger <[email-masked]>
Date: Fri, 13 Jan 2017 11:41:58 -0800

On Fri, 13 Jan 2017 11:12:32 -0800
Ben Greear <[email-masked]> wrote:

> I am including netinet/ip.h, and also linux/if_tunnel.h, and the linux/ip.h conflicts with
> netinet/ip.h.
> 
> Maybe my build environment is screwed up, but maybe also it would be better to
> just let the user include appropriate headers before including if_tunnel.h
> and revert this patch?
> 
> 
> include/uapi/linux/if_tunnel.h: include linux/if.h, linux/ip.h and linux/in6.h
> 
>      Fixes userspace compilation errors like:
> 
>      error: field ‘iph’ has incomplete type
>      error: field ‘prefix’ has incomplete type
> 
>      Signed-off-by: Mikko Rapeli <[email-masked]>
>      Signed-off-by: David S. Miller <[email-masked]>
> 
> Thanks,
> Ben
> 

What I ended up doing for iproute2 was including all headers used by the source
based on sanitized kernel headers.  Basically
  $ git grep '^#include <linux/' | \
	awk -F: '{print $2}' | \
	sed -e 's/^#include <//' -e 's/>.*$//' | \
	sort -u >linux.headers
   $ for f in $(cat linux.headers)
     do cp ~/kernel/net-next/usr/include/$f include/$f
     done

You can't take only some of the headers, once you decide to diverge from glibc provided
headers, you got to take them all.