Documentation: Add the RPC language description of NLM version 4

In order to generate source code to encode and decode NLMv4 protocol
elements, include a copy of the RPC language description of NLMv4
for xdrgen to process. The language description is an amalgam of
RFC 1813 and the Open Group's XNFS specification:

  https://pubs.opengroup.org/onlinepubs/9629799/chap10.htm

The C code committed here was generated from the new nlm4.x file
using tools/net/sunrpc/xdrgen/xdrgen.

The goals of replacing hand-written XDR functions with ones that
are tool-generated are to improve memory safety and make XDR
encoding and decoding less brittle to maintain.

The xdrgen utility derives both the type definitions and the
encode/decode functions directly from protocol specifications,
using names and symbols familiar to anyone who knows those specs.
Unlike hand-written code that can inadvertently diverge from the
specification, xdrgen guarantees that the generated code matches
the specification exactly.

We would eventually like xdrgen to generate Rust code as well,
making the conversion of the kernel's NFS stacks to use Rust just
a little easier for us.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

1 files changed, 233 insertions, 0 deletions

diff --git a/include/linux/sunrpc/xdrgen/nlm4.h b/include/linux/sunrpc/xdrgen/nlm4.h
new file mode 100644
index 000000000000..e95e8f105624
--- /dev/null
+++ b/include/linux/sunrpc/xdrgen/nlm4.h
@@ -0,0 +1,233 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Generated by xdrgen. Manual edits will be lost. */
+/* XDR specification file: ../../Documentation/sunrpc/xdr/nlm4.x */
+/* XDR specification modification time: Thu Dec 25 13:10:19 2025 */
+
+#ifndef _LINUX_XDRGEN_NLM4_DEF_H
+#define _LINUX_XDRGEN_NLM4_DEF_H
+
+#include <linux/types.h>
+#include <linux/sunrpc/xdrgen/_defs.h>
+
+enum { LM_MAXSTRLEN = 1024 };
+
+enum { LM_MAXNAMELEN = 1025 };
+
+enum { MAXNETOBJ_SZ = 1024 };
+
+typedef opaque netobj;
+
+enum fsh4_mode {
+	fsm_DN = 0,
+	fsm_DR = 1,
+	fsm_DW = 2,
+	fsm_DRW = 3,
+};
+
+typedef enum fsh4_mode fsh4_mode;
+
+enum fsh4_access {
+	fsa_NONE = 0,
+	fsa_R = 1,
+	fsa_W = 2,
+	fsa_RW = 3,
+};
+
+typedef enum fsh4_access fsh4_access;
+
+enum { SM_MAXSTRLEN = 1024 };
+
+typedef u64 uint64;
+
+typedef s64 int64;
+
+typedef u32 uint32;
+
+typedef s32 int32;
+
+enum nlm4_stats {
+	NLM4_GRANTED = 0,
+	NLM4_DENIED = 1,
+	NLM4_DENIED_NOLOCKS = 2,
+	NLM4_BLOCKED = 3,
+	NLM4_DENIED_GRACE_PERIOD = 4,
+	NLM4_DEADLCK = 5,
+	NLM4_ROFS = 6,
+	NLM4_STALE_FH = 7,
+	NLM4_FBIG = 8,
+	NLM4_FAILED = 9,
+};
+
+typedef __be32 nlm4_stats;
+
+struct nlm4_holder {
+	bool exclusive;
+	int32 svid;
+	netobj oh;
+	uint64 l_offset;
+	uint64 l_len;
+};
+
+struct nlm4_testrply {
+	nlm4_stats stat;
+	union {
+		struct nlm4_holder holder;
+	} u;
+};
+
+struct nlm4_stat {
+	nlm4_stats stat;
+};
+
+struct nlm4_res {
+	netobj cookie;
+	struct nlm4_stat stat;
+};
+
+struct nlm4_testres {
+	netobj cookie;
+	struct nlm4_testrply stat;
+};
+
+struct nlm4_lock {
+	string caller_name;
+	netobj fh;
+	netobj oh;
+	int32 svid;
+	uint64 l_offset;
+	uint64 l_len;
+};
+
+struct nlm4_lockargs {
+	netobj cookie;
+	bool block;
+	bool exclusive;
+	struct nlm4_lock alock;
+	bool reclaim;
+	int32 state;
+};
+
+struct nlm4_cancargs {
+	netobj cookie;
+	bool block;
+	bool exclusive;
+	struct nlm4_lock alock;
+};
+
+struct nlm4_testargs {
+	netobj cookie;
+	bool exclusive;
+	struct nlm4_lock alock;
+};
+
+struct nlm4_unlockargs {
+	netobj cookie;
+	struct nlm4_lock alock;
+};
+
+struct nlm4_share {
+	string caller_name;
+	netobj fh;
+	netobj oh;
+	fsh4_mode mode;
+	fsh4_access access;
+};
+
+struct nlm4_shareargs {
+	netobj cookie;
+	struct nlm4_share share;
+	bool reclaim;
+};
+
+struct nlm4_shareres {
+	netobj cookie;
+	nlm4_stats stat;
+	int32 sequence;
+};
+
+struct nlm4_notify {
+	string name;
+	int32 state;
+};
+
+enum { SM_PRIV_SIZE = 16 };
+
+struct nlm4_notifyargs {
+	struct nlm4_notify notify;
+	u8 private[SM_PRIV_SIZE];
+};
+
+enum {
+	NLMPROC4_NULL = 0,
+	NLMPROC4_TEST = 1,
+	NLMPROC4_LOCK = 2,
+	NLMPROC4_CANCEL = 3,
+	NLMPROC4_UNLOCK = 4,
+	NLMPROC4_GRANTED = 5,
+	NLMPROC4_TEST_MSG = 6,
+	NLMPROC4_LOCK_MSG = 7,
+	NLMPROC4_CANCEL_MSG = 8,
+	NLMPROC4_UNLOCK_MSG = 9,
+	NLMPROC4_GRANTED_MSG = 10,
+	NLMPROC4_TEST_RES = 11,
+	NLMPROC4_LOCK_RES = 12,
+	NLMPROC4_CANCEL_RES = 13,
+	NLMPROC4_UNLOCK_RES = 14,
+	NLMPROC4_GRANTED_RES = 15,
+	NLMPROC4_SM_NOTIFY = 16,
+	NLMPROC4_SHARE = 20,
+	NLMPROC4_UNSHARE = 21,
+	NLMPROC4_NM_LOCK = 22,
+	NLMPROC4_FREE_ALL = 23,
+};
+
+#ifndef NLM4_PROG
+#define NLM4_PROG (100021)
+#endif
+
+#define NLM4_netobj_sz                  (XDR_unsigned_int + XDR_QUADLEN(MAXNETOBJ_SZ))
+#define NLM4_fsh4_mode_sz               (XDR_int)
+#define NLM4_fsh4_access_sz             (XDR_int)
+#define NLM4_uint64_sz                  \
+	(XDR_unsigned_hyper)
+#define NLM4_int64_sz                   \
+	(XDR_hyper)
+#define NLM4_uint32_sz                  \
+	(XDR_unsigned_long)
+#define NLM4_int32_sz                   \
+	(XDR_long)
+#define NLM4_nlm4_stats_sz              (XDR_int)
+#define NLM4_nlm4_holder_sz             \
+	(XDR_bool + NLM4_int32_sz + NLM4_netobj_sz + NLM4_uint64_sz + NLM4_uint64_sz)
+#define NLM4_nlm4_testrply_sz           \
+	(NLM4_nlm4_stats_sz + NLM4_nlm4_holder_sz)
+#define NLM4_nlm4_stat_sz               \
+	(NLM4_nlm4_stats_sz)
+#define NLM4_nlm4_res_sz                \
+	(NLM4_netobj_sz + NLM4_nlm4_stat_sz)
+#define NLM4_nlm4_testres_sz            \
+	(NLM4_netobj_sz + NLM4_nlm4_testrply_sz)
+#define NLM4_nlm4_lock_sz               \
+	(XDR_unsigned_int + XDR_QUADLEN(LM_MAXSTRLEN) + NLM4_netobj_sz + NLM4_netobj_sz + NLM4_int32_sz + NLM4_uint64_sz + NLM4_uint64_sz)
+#define NLM4_nlm4_lockargs_sz           \
+	(NLM4_netobj_sz + XDR_bool + XDR_bool + NLM4_nlm4_lock_sz + XDR_bool + NLM4_int32_sz)
+#define NLM4_nlm4_cancargs_sz           \
+	(NLM4_netobj_sz + XDR_bool + XDR_bool + NLM4_nlm4_lock_sz)
+#define NLM4_nlm4_testargs_sz           \
+	(NLM4_netobj_sz + XDR_bool + NLM4_nlm4_lock_sz)
+#define NLM4_nlm4_unlockargs_sz         \
+	(NLM4_netobj_sz + NLM4_nlm4_lock_sz)
+#define NLM4_nlm4_share_sz              \
+	(XDR_unsigned_int + XDR_QUADLEN(LM_MAXSTRLEN) + NLM4_netobj_sz + NLM4_netobj_sz + NLM4_fsh4_mode_sz + NLM4_fsh4_access_sz)
+#define NLM4_nlm4_shareargs_sz          \
+	(NLM4_netobj_sz + NLM4_nlm4_share_sz + XDR_bool)
+#define NLM4_nlm4_shareres_sz           \
+	(NLM4_netobj_sz + NLM4_nlm4_stats_sz + NLM4_int32_sz)
+#define NLM4_nlm4_notify_sz             \
+	(XDR_unsigned_int + XDR_QUADLEN(LM_MAXNAMELEN) + NLM4_int32_sz)
+#define NLM4_nlm4_notifyargs_sz         \
+	(NLM4_nlm4_notify_sz + XDR_QUADLEN(SM_PRIV_SIZE))
+#define NLM4_MAX_ARGS_SZ                \
+	(NLM4_nlm4_lockargs_sz)
+
+#endif /* _LINUX_XDRGEN_NLM4_DEF_H */