> 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?
ack, I will fix it.
>
>
> >
> > 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?
ack, fine, I will fix it.
>
> > + 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
ack, fine, I will fix it (I am still used to 79 char limits :))
Regards,
Lorenzo
>
> > + 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;
> > }
> >
>
> [...]
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