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

[Daniel Borkmann]

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 <eric@xxxxxxxxx>
> Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> 
> remote rtne
> 
> Signed-off-by: Eric Leblond <eric@xxxxxxxxx>

Some leftover artifact from squashing commits?

>  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?

>  #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?

>  /*
>   * When building perf, unistd.h is overridden. __NR_bpf is
>   * required to be defined explicitly.
> @@ -441,6 +445,7 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
>  	struct nlmsghdr *nh;
>  	struct nlmsgerr *err;
>  	socklen_t addrlen;