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

On Wed, 2021-06-02 at 19:58 +0200, Florian Weimer wrote:

* Andreas Roeseler:

quoted

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.