NFSD: introduce netlink stubs

Generate stubs and uAPI for nfsd netlink protocol. For the moment,
the new protocol has one operation: rpc_status.

The generated header and source files are created by running:

  tools/net/ynl/ynl-regen.sh

Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Documentation/netlink/specs/nfsd.yaml

+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+
+name: nfsd
+protocol: genetlink
+uapi-header: linux/nfsd_netlink.h
+
+doc: NFSD configuration over generic netlink.
+
+attribute-sets:
+  -
+    name: rpc-status
+    attributes:
+      -
+        name: xid
+        type: u32
+        byte-order: big-endian
+      -
+        name: flags
+        type: u32
+      -
+        name: prog
+        type: u32
+      -
+        name: version
+        type: u8
+      -
+        name: proc
+        type: u32
+      -
+        name: service_time
+        type: s64
+      -
+        name: pad
+        type: pad
+      -
+        name: saddr4
+        type: u32
+        byte-order: big-endian
+        display-hint: ipv4
+      -
+        name: daddr4
+        type: u32
+        byte-order: big-endian
+        display-hint: ipv4
+      -
+        name: saddr6
+        type: binary
+        display-hint: ipv6
+      -
+        name: daddr6
+        type: binary
+        display-hint: ipv6
+      -
+        name: sport
+        type: u16
+        byte-order: big-endian
+      -
+        name: dport
+        type: u16
+        byte-order: big-endian
+      -
+        name: compound-ops
+        type: u32
+        multi-attr: true
+
+operations:
+  list:
+    -
+      name: rpc-status-get
+      doc: dump pending nfsd rpc
+      attribute-set: rpc-status
+      dump:
+        pre: nfsd-nl-rpc-status-get-start
+        post: nfsd-nl-rpc-status-get-done
+        reply:
+          attributes:
+            - xid
+            - flags
+            - prog
+            - version
+            - proc
+            - service_time
+            - saddr4
+            - daddr4
+            - saddr6
+            - daddr6
+            - sport
+            - dport
+            - compound-ops

fs/nfsd/Makefile

@@ -12,7 +12,8 @@ nfsd-y			+= trace.o
 
 nfsd-y 			+= nfssvc.o nfsctl.o nfsfh.o vfs.o \
 			   export.o auth.o lockd.o nfscache.o \
-			   stats.o filecache.o nfs3proc.o nfs3xdr.o
+			   stats.o filecache.o nfs3proc.o nfs3xdr.o \
+			   netlink.o
 nfsd-$(CONFIG_NFSD_V2) += nfsproc.o nfsxdr.o
 nfsd-$(CONFIG_NFSD_V2_ACL) += nfs2acl.o
 nfsd-$(CONFIG_NFSD_V3_ACL) += nfs3acl.o

fs/nfsd/netlink.c

+// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/nfsd.yaml */
+/* YNL-GEN kernel source */
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "netlink.h"
+
+#include <uapi/linux/nfsd_netlink.h>
+
+/* Ops table for nfsd */
+static const struct genl_split_ops nfsd_nl_ops[] = {
+	{
+		.cmd	= NFSD_CMD_RPC_STATUS_GET,
+		.start	= nfsd_nl_rpc_status_get_start,
+		.dumpit	= nfsd_nl_rpc_status_get_dumpit,
+		.done	= nfsd_nl_rpc_status_get_done,
+		.flags	= GENL_CMD_CAP_DUMP,
+	},
+};
+
+struct genl_family nfsd_nl_family __ro_after_init = {
+	.name		= NFSD_FAMILY_NAME,
+	.version	= NFSD_FAMILY_VERSION,
+	.netnsok	= true,
+	.parallel_ops	= true,
+	.module		= THIS_MODULE,
+	.split_ops	= nfsd_nl_ops,
+	.n_split_ops	= ARRAY_SIZE(nfsd_nl_ops),
+};

fs/nfsd/netlink.h

+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/nfsd.yaml */
+/* YNL-GEN kernel header */
+
+#ifndef _LINUX_NFSD_GEN_H
+#define _LINUX_NFSD_GEN_H
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <uapi/linux/nfsd_netlink.h>
+
+int nfsd_nl_rpc_status_get_start(struct netlink_callback *cb);
+int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb);
+
+int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
+				  struct netlink_callback *cb);
+
+extern struct genl_family nfsd_nl_family;
+
+#endif /* _LINUX_NFSD_GEN_H */

fs/nfsd/nfsctl.c

@@ -26,6 +26,7 @@
 #include "pnfs.h"
 #include "filecache.h"
 #include "trace.h"
+#include "netlink.h"
 
 /*
  *	We have a single directory with several nodes in it.
@@ -1495,6 +1496,22 @@ static int create_proc_exports_entry(void)
 
 unsigned int nfsd_net_id;
 
+int nfsd_nl_rpc_status_get_start(struct netlink_callback *cb)
+{
+	return 0;
+}
+
+int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
+				  struct netlink_callback *cb)
+{
+	return 0;
+}
+
+int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
+{
+	return 0;
+}
+
 /**
  * nfsd_net_init - Prepare the nfsd_net portion of a new net namespace
  * @net: a freshly-created network namespace

include/uapi/linux/nfsd_netlink.h

+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/nfsd.yaml */
+/* YNL-GEN uapi header */
+
+#ifndef _UAPI_LINUX_NFSD_H
+#define _UAPI_LINUX_NFSD_H
+
+#define NFSD_FAMILY_NAME	"nfsd"
+#define NFSD_FAMILY_VERSION	1
+
+enum {
+	NFSD_A_RPC_STATUS_XID = 1,
+	NFSD_A_RPC_STATUS_FLAGS,
+	NFSD_A_RPC_STATUS_PROG,
+	NFSD_A_RPC_STATUS_VERSION,
+	NFSD_A_RPC_STATUS_PROC,
+	NFSD_A_RPC_STATUS_SERVICE_TIME,
+	NFSD_A_RPC_STATUS_PAD,
+	NFSD_A_RPC_STATUS_SADDR4,
+	NFSD_A_RPC_STATUS_DADDR4,
+	NFSD_A_RPC_STATUS_SADDR6,
+	NFSD_A_RPC_STATUS_DADDR6,
+	NFSD_A_RPC_STATUS_SPORT,
+	NFSD_A_RPC_STATUS_DPORT,
+	NFSD_A_RPC_STATUS_COMPOUND_OPS,
+
+	__NFSD_A_RPC_STATUS_MAX,
+	NFSD_A_RPC_STATUS_MAX = (__NFSD_A_RPC_STATUS_MAX - 1)
+};
+
+enum {
+	NFSD_CMD_RPC_STATUS_GET = 1,
+
+	__NFSD_CMD_MAX,
+	NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)
+};
+
+#endif /* _UAPI_LINUX_NFSD_H */