Re: [PATCH iproute2 master] bpf: provide fallback defs for __NR_bpf when not avail

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 15 Jun 2017 00:47:15 +0200
Daniel Borkmann <daniel@iogearbox.net> wrote:

> panji reported that he wasn't able to build iproute2's bpf library
> due to lack of __NR_bpf in his system headers. Providing a fallback
> definition when __NR_bpf is not available in the system lets the
> loader compile just fine, so lets add them for majority of archs.
> 
> Reported-by: panji <jpan@live.nl>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> ---
>  lib/bpf.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/lib/bpf.c b/lib/bpf.c
> index ae4d97d..e1e29cc 100644
> --- a/lib/bpf.c
> +++ b/lib/bpf.c
> @@ -128,6 +128,26 @@ static inline __u64 bpf_ptr_to_u64(const void *ptr)
>  	return (__u64)(unsigned long)ptr;
>  }
>  
> +#ifndef __NR_bpf
> +# if defined(__i386__)
> +#  define __NR_bpf 357
> +# elif defined(__x86_64__)
> +#  define __NR_bpf 321
> +# elif defined(__aarch64__)
> +#  define __NR_bpf 280
> +# elif defined(__sparc__)
> +#  define __NR_bpf 349
> +# elif defined(__arm__)
> +#  define __NR_bpf 386
> +# elif defined(__powerpc__)
> +#  define __NR_bpf 361
> +# elif defined(__s390__)
> +#  define __NR_bpf 351
> +# else
> +#  error __NR_bpf not defined. Update kernel headers.
> +# endif
> +#endif
> +
>  static int bpf(int cmd, union bpf_attr *attr, unsigned int size)
>  {
>  #ifdef __NR_bpf

Sorry this looks like a mess. enumerating architectures in two different
projects is likely to break in future.