Subject: Re: [PATCH bpf-next v7 3/5] libbpf: add error reporting in XDP

From: Eric Leblond <[email-masked]>
Date: Sat, 27 Jan 2018 11:32:06 +0100

Hi,

On Sat, 2018-01-27 at 02:28 +0100, Daniel Borkmann wrote:
> On 01/25/2018 01:05 AM, Eric Leblond wrote:
> > Parse netlink ext attribute to get the error message returned by
> > the card. Code is partially take from libnl.
> > 
> > We add netlink.h to the uapi include of tools. And we need to
> > avoid include of userspace netlink header to have a successful
> > build of sample so nlattr.h has a define to avoid
> > the inclusion. Using a direct define could have been an issue
> > as NLMSGERR_ATTR_MAX can change in the future.
> > 
> > We also define SOL_NETLINK if not defined to avoid to have to
> > copy socket.h for a fixed value.
> > 
> > Signed-off-by: Eric Leblond <[email-masked]>
> > Acked-by: Alexei Starovoitov <[email-masked]>
> > 
> > remote rtne
> > 
> > Signed-off-by: Eric Leblond <[email-masked]>
> 
> Some leftover artifact from squashing commits?

Outch

> >  samples/bpf/Makefile   |   2 +-
> >  tools/lib/bpf/Build    |   2 +-
> >  tools/lib/bpf/bpf.c    |  13 +++-
> >  tools/lib/bpf/nlattr.c | 187
> > +++++++++++++++++++++++++++++++++++++++++++++++++
> >  tools/lib/bpf/nlattr.h |  72 +++++++++++++++++++
> >  5 files changed, 273 insertions(+), 3 deletions(-)
> >  create mode 100644 tools/lib/bpf/nlattr.c
> >  create mode 100644 tools/lib/bpf/nlattr.h
> > 
> > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> > index 7f61a3d57fa7..5c4cd3745282 100644
> > --- a/samples/bpf/Makefile
> > +++ b/samples/bpf/Makefile
> > @@ -45,7 +45,7 @@ hostprogs-y += xdp_rxq_info
> >  hostprogs-y += syscall_tp
> >  
> >  # Libbpf dependencies
> > -LIBBPF := ../../tools/lib/bpf/bpf.o
> > +LIBBPF := ../../tools/lib/bpf/bpf.o ../../tools/lib/bpf/nlattr.o
> >  CGROUP_HELPERS :=
> > ../../tools/testing/selftests/bpf/cgroup_helpers.o
> >  
> >  test_lru_dist-objs := test_lru_dist.o $(LIBBPF)
> > diff --git a/tools/lib/bpf/Build b/tools/lib/bpf/Build
> > index d8749756352d..64c679d67109 100644
> > --- a/tools/lib/bpf/Build
> > +++ b/tools/lib/bpf/Build
> > @@ -1 +1 @@
> > -libbpf-y := libbpf.o bpf.o
> > +libbpf-y := libbpf.o bpf.o nlattr.o
> > diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> > index 749a447ec9ed..765fd95b0657 100644
> > --- a/tools/lib/bpf/bpf.c
> > +++ b/tools/lib/bpf/bpf.c
> > @@ -27,7 +27,7 @@
> >  #include "bpf.h"
> >  #include "libbpf.h"
> >  #include "nlattr.h"
> > -#include <uapi/linux/rtnetlink.h>
> > +#include <linux/rtnetlink.h>
> 
> Okay, so here it's put back from prior added uapi/linux/rtnetlink.h
> into linux/rtnetlink.h. Could you add this properly in the first
> commit rather than relative adjustment/fix within the same set?

Yes, sure.

> >  #include <sys/socket.h>
> >  #include <errno.h>
> >  
> > @@ -37,6 +37,10 @@
> >  #define IFLA_XDP_FLAGS	3
> >  #endif
> >  
> > +#ifndef SOL_NETLINK
> > +#define SOL_NETLINK 270
> > +#endif
> 
> This would need include/linux/socket.h into tools/ include infra
> as well, no?

Yes, and I fear a lot of dependencies.

++
-- 
Eric Leblond <[email-masked]>
Blog: https://home.regit.org/