On Wed, Feb 1, 2023 at 2:25 AM Lorenzo Bianconi <lorenzo@xxxxxxxxxx> wrote:
>
> Extend bpf_xdp_query routine in order to get XDP/XSK supported features
> of netdev over route netlink interface.
> Extend libbpf netlink implementation in order to support netlink_generic
> protocol.
>
> Co-developed-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
> Co-developed-by: Marek Majtyka <alardam@xxxxxxxxx>
> Signed-off-by: Marek Majtyka <alardam@xxxxxxxxx>
> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> ---
> tools/lib/bpf/libbpf.h | 3 +-
> tools/lib/bpf/netlink.c | 96 +++++++++++++++++++++++++++++++++++++++++
> tools/lib/bpf/nlattr.h | 12 ++++++
> 3 files changed, 110 insertions(+), 1 deletion(-)
>
[...]
> @@ -366,6 +433,10 @@ int bpf_xdp_query(int ifindex, int xdp_flags, struct bpf_xdp_query_opts *opts)
> .ifinfo.ifi_family = AF_PACKET,
> };
> struct xdp_id_md xdp_id = {};
> + struct xdp_features_md md = {
> + .ifindex = ifindex,
> + };
> + __u16 id;
> int err;
>
> if (!OPTS_VALID(opts, bpf_xdp_query_opts))
> @@ -393,6 +464,31 @@ int bpf_xdp_query(int ifindex, int xdp_flags, struct bpf_xdp_query_opts *opts)
> OPTS_SET(opts, skb_prog_id, xdp_id.info.skb_prog_id);
> OPTS_SET(opts, attach_mode, xdp_id.info.attach_mode);
>
> + if (!OPTS_HAS(opts, feature_flags))
> + return 0;
> +
> + err = libbpf_netlink_resolve_genl_family_id("netdev", sizeof("netdev"), &id);
> + if (err < 0)
> + return libbpf_err(err);
> +
> + memset(&req, 0, sizeof(req));
> + req.nh.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
> + req.nh.nlmsg_flags = NLM_F_REQUEST;
> + req.nh.nlmsg_type = id;
> + req.gnl.cmd = NETDEV_CMD_DEV_GET;
> + req.gnl.version = 2;
> +
> + err = nlattr_add(&req, NETDEV_A_DEV_IFINDEX, &ifindex, sizeof(ifindex));
> + if (err < 0)
> + return err;
just noticed this, we need to use libbpf_err(err) here like in other
error cases to set errno properly. Can you please send a follow up?
> +
> + err = libbpf_netlink_send_recv(&req, NETLINK_GENERIC,
> + parse_xdp_features, NULL, &md);
> + if (err)
> + return libbpf_err(err);
> +
> + opts->feature_flags = md.flags;
> +
> return 0;
> }
>
[...]
