netdev-genl: create a simple family for netdev stuff

Add a Netlink spec-compatible family for netdevs.
This is a very simple implementation without much
thought going into it.

It allows us to reap all the benefits of Netlink specs,
one can use the generic client to issue the commands:

  $ ./cli.py --spec netdev.yaml --dump dev_get
  [{'ifindex': 1, 'xdp-features': set()},
   {'ifindex': 2, 'xdp-features': {'basic', 'ndo-xmit', 'redirect'}},
   {'ifindex': 3, 'xdp-features': {'rx-sg'}}]

the generic python library does not have flags-by-name
support, yet, but we also don't have to carry strings
in the messages, as user space can get the names from
the spec.

Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Co-developed-by: Marek Majtyka <alardam@gmail.com>
Signed-off-by: Marek Majtyka <alardam@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/327ad9c9868becbe1e601b580c962549c8cd81f2.1675245258.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 100 insertions, 0 deletions

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
new file mode 100644
index 00000000000000..b4dcdae54ffd2e
--- /dev/null
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -0,0 +1,100 @@
+name: netdev
+
+doc:
+  netdev configuration over generic netlink.
+
+definitions:
+  -
+    type: flags
+    name: xdp-act
+    entries:
+      -
+        name: basic
+        doc:
+          XDP feautues set supported by all drivers
+          (XDP_ABORTED, XDP_DROP, XDP_PASS, XDP_TX)
+      -
+        name: redirect
+        doc:
+          The netdev supports XDP_REDIRECT
+      -
+        name: ndo-xmit
+        doc:
+          This feature informs if netdev implements ndo_xdp_xmit callback.
+      -
+        name: xsk-zerocopy
+        doc:
+          This feature informs if netdev supports AF_XDP in zero copy mode.
+      -
+        name: hw-offload
+        doc:
+         This feature informs if netdev supports XDP hw oflloading.
+      -
+        name: rx-sg
+        doc:
+          This feature informs if netdev implements non-linear XDP buffer
+          support in the driver napi callback.
+      -
+        name: ndo-xmit-sg
+        doc:
+          This feature informs if netdev implements non-linear XDP buffer
+          support in ndo_xdp_xmit callback.
+
+attribute-sets:
+  -
+    name: dev
+    attributes:
+      -
+        name: ifindex
+        doc: netdev ifindex
+        type: u32
+        value: 1
+        checks:
+          min: 1
+      -
+        name: pad
+        type: pad
+      -
+        name: xdp-features
+        doc: Bitmask of enabled xdp-features.
+        type: u64
+        enum: xdp-act
+        enum-as-flags: true
+
+operations:
+  list:
+    -
+      name: dev-get
+      doc: Get / dump information about a netdev.
+      value: 1
+      attribute-set: dev
+      do:
+        request:
+          attributes:
+            - ifindex
+        reply: &dev-all
+          attributes:
+            - ifindex
+            - xdp-features
+      dump:
+        reply: *dev-all
+    -
+      name: dev-add-ntf
+      doc: Notification about device appearing.
+      notify: dev-get
+      mcgrp: mgmt
+    -
+      name: dev-del-ntf
+      doc: Notification about device disappearing.
+      notify: dev-get
+      mcgrp: mgmt
+    -
+      name: dev-change-ntf
+      doc: Notification about device configuration being changed.
+      notify: dev-get
+      mcgrp: mgmt
+
+mcast-groups:
+  list:
+    -
+      name: mgmt