Re: [PATCH net-next V6 1/6] icmp: add support for RFC 8335 PROBE

[Andreas Roeseler <andreas.a.roeseler@gmail.com>]

On Wed, 2021-06-02 at 19:58 +0200, Florian Weimer wrote:
> * Andreas Roeseler:
> 
> > diff --git a/include/uapi/linux/icmp.h b/include/uapi/linux/icmp.h
> > index fb169a50895e..222325d1d80e 100644
> > --- a/include/uapi/linux/icmp.h
> > +++ b/include/uapi/linux/icmp.h
> > @@ -20,6 +20,9 @@
> >  
> >  #include <linux/types.h>
> >  #include <asm/byteorder.h>
> > +#include <linux/in.h>
> > +#include <linux/if.h>
> > +#include <linux/in6.h>
> 
> We have received a report that this breaks compiliation of trinity
> because it includes <netinet/in.h> and <linux/icmp.h> at the same
> time,
> and there is no multiple-definition guard for struct in_addr and
> other
> definitions:
> 
> In file included from include/net.h:5,
>                  from net/proto-ip-raw.c:2:
> /usr/include/netinet/in.h:31:8: error: redefinition of ‘struct
> in_addr’
>    31 | struct in_addr
>       |        ^~~~~~~
> In file included from /usr/include/linux/icmp.h:23,
>                  from net/proto-ip-raw.c:1:
> /usr/include/linux/in.h:89:8: note: originally defined here
>    89 | struct in_addr {
>       |        ^~~~~~~
> In file included from /usr/include/netinet/in.h:37,
>                  from include/net.h:5,
>                  from net/proto-ip-raw.c:2:
> /usr/include/bits/in.h:150:8: error: redefinition of ‘struct
> ip_mreqn’
>   150 | struct ip_mreqn
>       |        ^~~~~~~~
> In file included from /usr/include/linux/icmp.h:23,
>                  from net/proto-ip-raw.c:1:
> /usr/include/linux/in.h:178:8: note: originally defined here
>   178 | struct ip_mreqn {
>       |        ^~~~~~~~
> 
> (More conflicts appear to follow.)
> 
> I do not know what the correct way forward is.  Adding the
> multiple-definition guards is quite a bit of work and requires
> updates
> in glibc and the kernel to work properly.
> 
> Thanks,
> Florian
> 

Are <netinet/in.h> and <linux/in.h> the only conflicting files?
<linux/in.h> is only included to gain use of the in_addr struct, but
that can be easily substituted out of the code in favor of __be32.
Therefore we would no longer need to include <linux/in.h> and would
remove the conflict.