Re: [PATCH bpf-next 2/3] libbpf: add error reporting in XDP

[Alexei Starovoitov]

On Mon, Dec 25, 2017 at 11:13:24PM +0100, Eric Leblond wrote:
> Parse netlink ext attribute to get the error message returned by
> the card.
> 
> Signed-off-by: Eric Leblond <eric@xxxxxxxxx>
...
> diff --git a/tools/lib/bpf/nlattr.c b/tools/lib/bpf/nlattr.c
> new file mode 100644
> index 000000000000..962de14f74e3
> --- /dev/null
> +++ b/tools/lib/bpf/nlattr.c
> @@ -0,0 +1,188 @@
> +
> +/*
> + * NETLINK      Netlink attributes
> + *
> + *		Authors:	Thomas Graf <tgraf@xxxxxxx>
> + *				Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>
> + */
...
> diff --git a/tools/lib/bpf/nlattr.h b/tools/lib/bpf/nlattr.h
> new file mode 100644
> index 000000000000..b95f3e64c14d
> --- /dev/null
> +++ b/tools/lib/bpf/nlattr.h
> @@ -0,0 +1,164 @@
> +#ifndef __NLATTR_H
> +#define __NLATTR_H

Every file in kernel repo has to have SPDX license identifier.
Also note that tools/lib/bpf is LGPL whereas _if_ you're copying
these functions from kernel lib/nlattr.c then it's GPL which we cannot mix.
Probably easier to copy from libnl instead which is LGPL.