Re: [PATCH v2] fix compile errors due to unsync linux/in6.h and netinet/in.h

[Yonghong Song <yhs@fb.com>]

On 4/18/19 11:05 AM, Wang YanQing wrote:
> I meet below compile errors:
> "
> In file included from test_tcpnotify_kern.c:12:
> /usr/include/netinet/in.h:101:5: error: expected identifier
>      IPPROTO_HOPOPTS = 0,   /* IPv6 Hop-by-Hop options.  */
>      ^
> /usr/include/linux/in6.h:131:26: note: expanded from macro 'IPPROTO_HOPOPTS'
>                                  ^
> In file included from test_tcpnotify_kern.c:12:
> /usr/include/netinet/in.h:103:5: error: expected identifier
>      IPPROTO_ROUTING = 43,  /* IPv6 routing header.  */
>      ^
> /usr/include/linux/in6.h:132:26: note: expanded from macro 'IPPROTO_ROUTING'
>                                  ^
> In file included from test_tcpnotify_kern.c:12:
> /usr/include/netinet/in.h:105:5: error: expected identifier
>      IPPROTO_FRAGMENT = 44, /* IPv6 fragmentation header.  */
>      ^
> /usr/include/linux/in6.h:133:26: note: expanded from macro 'IPPROTO_FRAGMENT'
> "
> The same compile errors are reported for test_tcpbpf_kern.c too.
> 
> My environment:
> lsb_release -a:
> No LSB modules are available.
> Distributor ID: Ubuntu
> Description:    Ubuntu 16.04.6 LTS
> Release:        16.04
> Codename:       xenial
> 
> dpkg -l | grep libc-dev:
> ii  libc-dev-bin              2.23-0ubuntu11           amd64        GNU C Library: Development binaries
> ii  linux-libc-dev:amd64      4.4.0-145.171            amd64        Linux Kernel Headers for development.
> 
> The reason is linux/in6.h and netinet/in.h aren't synchronous about how to
> handle the same definitions, IPPROTO_HOPOPTS, etc.
> 
> This patch fixes the compile errors by moving <netinet/in.h> to before the
> <linux/*.h>.
> 
> Signed-off-by: Wang YanQing <udknight@gmail.com>

Tested and the change makes sense. By changing the include order, now we 
have linux checks the existence of macro _NETINET_IN_H instead of
certain versions of glibc checks _UAPI_LINUX_IN6_H which does not exist
for all recent kernels (at least 4.4 and onwards).

Acked-by: Yonghong Song <yhs@fb.com>


> ---
>   Changes
>   v1-v2:
>   1:Rewrite the changelog.
> 
>   tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c    | 2 +-
>   tools/testing/selftests/bpf/progs/test_tcpnotify_kern.c | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c b/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
> index 74f73b3..c7c3240 100644
> --- a/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
> +++ b/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
> @@ -1,6 +1,7 @@
>   // SPDX-License-Identifier: GPL-2.0
>   #include <stddef.h>
>   #include <string.h>
> +#include <netinet/in.h>
>   #include <linux/bpf.h>
>   #include <linux/if_ether.h>
>   #include <linux/if_packet.h>
> @@ -9,7 +10,6 @@
>   #include <linux/types.h>
>   #include <linux/socket.h>
>   #include <linux/tcp.h>
> -#include <netinet/in.h>
>   #include "bpf_helpers.h"
>   #include "bpf_endian.h"
>   #include "test_tcpbpf.h"
> diff --git a/tools/testing/selftests/bpf/progs/test_tcpnotify_kern.c b/tools/testing/selftests/bpf/progs/test_tcpnotify_kern.c
> index edbca20..ec6db6e 100644
> --- a/tools/testing/selftests/bpf/progs/test_tcpnotify_kern.c
> +++ b/tools/testing/selftests/bpf/progs/test_tcpnotify_kern.c
> @@ -1,6 +1,7 @@
>   // SPDX-License-Identifier: GPL-2.0
>   #include <stddef.h>
>   #include <string.h>
> +#include <netinet/in.h>
>   #include <linux/bpf.h>
>   #include <linux/if_ether.h>
>   #include <linux/if_packet.h>
> @@ -9,7 +10,6 @@
>   #include <linux/types.h>
>   #include <linux/socket.h>
>   #include <linux/tcp.h>
> -#include <netinet/in.h>
>   #include "bpf_helpers.h"
>   #include "bpf_endian.h"
>   #include "test_tcpnotify.h"
>