bpf: XDP metadata RX kfuncs

Define a new kfunc set (xdp_metadata_kfunc_ids) which implements all possible
XDP metatada kfuncs. Not all devices have to implement them. If kfunc is not
supported by the target device, the default implementation is called instead.
The verifier, at load time, replaces a call to the generic kfunc with a call
to the per-device one. Per-device kfunc pointers are stored in separate
struct xdp_metadata_ops.

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-8-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

1 files changed, 16 insertions, 1 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index b97a05bb47be..bb26c2e18092 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2480,6 +2480,9 @@ bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev);
 void unpriv_ebpf_notify(int new_state);
 
 #if defined(CONFIG_NET) && defined(CONFIG_BPF_SYSCALL)
+int bpf_dev_bound_kfunc_check(struct bpf_verifier_log *log,
+			      struct bpf_prog_aux *prog_aux);
+void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog, u32 func_id);
 int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr);
 void bpf_dev_bound_netdev_unregister(struct net_device *dev);
 
@@ -2514,8 +2517,20 @@ void sock_map_unhash(struct sock *sk);
 void sock_map_destroy(struct sock *sk);
 void sock_map_close(struct sock *sk, long timeout);
 #else
+static inline int bpf_dev_bound_kfunc_check(struct bpf_verifier_log *log,
+					    struct bpf_prog_aux *prog_aux)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog,
+						u32 func_id)
+{
+	return NULL;
+}
+
 static inline int bpf_prog_dev_bound_init(struct bpf_prog *prog,
-					union bpf_attr *attr)
+					  union bpf_attr *attr)
 {
 	return -EOPNOTSUPP;
 }