On Thu, Jan 26, 2023 at 4:59 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 | 99 +++++++++++++++++++++++++++++++++++++++++
> tools/lib/bpf/nlattr.h | 12 +++++
> 3 files changed, 113 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 898db26e42e9..29cb7040fa77 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -982,9 +982,10 @@ struct bpf_xdp_query_opts {
> __u32 hw_prog_id; /* output */
> __u32 skb_prog_id; /* output */
> __u8 attach_mode; /* output */
> + __u64 fflags; /* output */
> size_t :0;
> };
> -#define bpf_xdp_query_opts__last_field attach_mode
> +#define bpf_xdp_query_opts__last_field fflags
is "fflags" an obvious name in this context? I'd expect
"feature_flags", especially that there are already "flags". Is saving
a few characters worth the confusion?
>
> LIBBPF_API int bpf_xdp_attach(int ifindex, int prog_fd, __u32 flags,
> const struct bpf_xdp_attach_opts *opts);
> diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
> index d2468a04a6c3..674e4d61e67e 100644
> --- a/tools/lib/bpf/netlink.c
> +++ b/tools/lib/bpf/netlink.c
> @@ -9,6 +9,7 @@
> #include <linux/if_ether.h>
> #include <linux/pkt_cls.h>
> #include <linux/rtnetlink.h>
> +#include <linux/netdev.h>
> #include <sys/socket.h>
> #include <errno.h>
> #include <time.h>
> @@ -39,6 +40,12 @@ struct xdp_id_md {
> int ifindex;
> __u32 flags;
> struct xdp_link_info info;
> + __u64 fflags;
> +};
> +
> +struct xdp_features_md {
> + int ifindex;
> + __u64 flags;
> };
>
> static int libbpf_netlink_open(__u32 *nl_pid, int proto)
[...]
> int bpf_xdp_query(int ifindex, int xdp_flags, struct bpf_xdp_query_opts *opts)
> {
> struct libbpf_nla_req req = {
> @@ -393,6 +460,38 @@ 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, fflags)) {
maybe invert condition, return early, reduce nesting of the following code?
> + struct xdp_features_md md = {
> + .ifindex = ifindex,
> + };
> + __u16 id;
> +
> + err = libbpf_netlink_resolve_genl_family_id("netdev",
> + sizeof("netdev"),
> + &id);
nit: if it fits under 100 characters, let's leave it on a single line
> + 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;
> +
> + err = libbpf_netlink_send_recv(&req, NETLINK_GENERIC,
> + parse_xdp_features, NULL, &md);
> + if (err)
> + return libbpf_err(err);
> +
> + opts->fflags = md.flags;
> + }
> +
> return 0;
> }
>
[...]
