path: root/fs/nfs/callback_xdr.c

// SPDX-License-Identifier: GPL-2.0
/*
 * linux/fs/nfs/callback_xdr.c
 *
 * Copyright (C) 2004 Trond Myklebust
 *
 * NFSv4 callback encode/decode procedures
 */
#include <linux/kernel.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/ratelimit.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/sunrpc/bc_xprt.h>
#include "nfs4_fs.h"
#include "callback.h"
#include "internal.h"
#include "nfs4session.h"
#include "nfs4trace.h"

#define CB_OP_TAGLEN_MAXSZ		(512)
#define CB_OP_HDR_RES_MAXSZ		(2 * 4) // opcode, status
#define CB_OP_GETATTR_BITMAP_MAXSZ	(4 * 4) // bitmap length, 3 bitmaps
#define CB_OP_GETATTR_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ + \
					 CB_OP_GETATTR_BITMAP_MAXSZ + \
					 /* change, size, atime, ctime,
					  * mtime, deleg_atime, deleg_mtime */\
					 (2 + 2 + 3 + 3 + 3 + 3 + 3) * 4)
#define CB_OP_RECALL_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ)

#if defined(CONFIG_NFS_V4_1)
#define CB_OP_LAYOUTRECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#define CB_OP_DEVICENOTIFY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
					 NFS4_MAX_SESSIONID_LEN + \
					 (1 + 3) * 4) // seqid, 3 slotids
#define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#define CB_OP_NOTIFY_LOCK_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
#endif /* CONFIG_NFS_V4_1 */
#ifdef CONFIG_NFS_V4_2
#define CB_OP_OFFLOAD_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ)
#endif /* CONFIG_NFS_V4_2 */

#define NFSDBG_FACILITY NFSDBG_CALLBACK

/* Internal error code */
#define NFS4ERR_RESOURCE_HDR	11050

struct callback_op {
	__be32 (*process_op)(void *, void *, struct cb_process_state *);
	__be32 (*decode_args)(struct svc_rqst *, struct xdr_stream *, void *);
	__be32 (*encode_res)(struct svc_rqst *, struct xdr_stream *,
			const void *);
	long res_maxsize;
};

static struct callback_op callback_ops[];

static __be32 nfs4_callback_null(struct svc_rqst *rqstp)
{
	return htonl(NFS4_OK);
}

/*
 * svc_process_common() looks for an XDR encoder to know when
 * not to drop a Reply.
 */
static bool nfs4_encode_void(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{
	return true;
}

static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len,
		const char **str, size_t maxlen)
{
	ssize_t err;

	err = xdr_stream_decode_opaque_inline(xdr, (void **)str, maxlen);
	if (err < 0)
		return cpu_to_be32(NFS4ERR_RESOURCE);
	*len = err;
	return 0;
}

static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
{
	__be32 *p;

	p = xdr_inline_decode(xdr, 4);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	fh->size = ntohl(*p);
	if (fh->size > NFS4_FHSIZE)
		return htonl(NFS4ERR_BADHANDLE);
	p = xdr_inline_decode(xdr, fh->size);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	memcpy(&fh->data[0], p, fh->size);
	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
	return 0;
}

static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
{
	__be32 *p;
	unsigned int attrlen;

	p = xdr_inline_decode(xdr, 4);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	attrlen = ntohl(*p);
	p = xdr_inline_decode(xdr, attrlen << 2);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	if (likely(attrlen > 0))
		bitmap[0] = ntohl(*p++);
	if (attrlen > 1)
		bitmap[1] = ntohl(*p++);
	if (attrlen > 2)
		bitmap[2] = ntohl(*p);
	return 0;
}

static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
{
	__be32 *p;

	p = xdr_inline_decode(xdr, NFS4_STATEID_SIZE);
	if (unlikely(p == NULL))
		return htonl(NFS4ERR_RESOURCE);
	memcpy(stateid->data, p, NFS4_STATEID_SIZE);
	return 0;
}

static __be32 decode_delegation_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
{
	stateid->type = NFS4_DELEGATION_STATEID_TYPE;
	return decode_stateid(xdr, stateid);
}

static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr</