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-rw-r--r--include/linux/sunrpc/xdr.h801
1 files changed, 801 insertions, 0 deletions
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
new file mode 100644
index 000000000..2f8dc47f1
--- /dev/null
+++ b/include/linux/sunrpc/xdr.h
@@ -0,0 +1,801 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * XDR standard data types and function declarations
+ *
+ * Copyright (C) 1995-1997 Olaf Kirch <okir@monad.swb.de>
+ *
+ * Based on:
+ * RFC 4506 "XDR: External Data Representation Standard", May 2006
+ */
+
+#ifndef _SUNRPC_XDR_H_
+#define _SUNRPC_XDR_H_
+
+#include <linux/uio.h>
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+#include <linux/scatterlist.h>
+
+struct bio_vec;
+struct rpc_rqst;
+
+/*
+ * Size of an XDR encoding unit in bytes, i.e. 32 bits,
+ * as defined in Section 3 of RFC 4506. All encoded
+ * XDR data items are aligned on a boundary of 32 bits.
+ */
+#define XDR_UNIT sizeof(__be32)
+
+/*
+ * Buffer adjustment
+ */
+#define XDR_QUADLEN(l) (((l) + 3) >> 2)
+
+/*
+ * Generic opaque `network object.'
+ */
+#define XDR_MAX_NETOBJ 1024
+struct xdr_netobj {
+ unsigned int len;
+ u8 * data;
+};
+
+/*
+ * Basic structure for transmission/reception of a client XDR message.
+ * Features a header (for a linear buffer containing RPC headers
+ * and the data payload for short messages), and then an array of
+ * pages.
+ * The tail iovec allows you to append data after the page array. Its
+ * main interest is for appending padding to the pages in order to
+ * satisfy the int_32-alignment requirements in RFC1832.
+ *
+ * For the future, we might want to string several of these together
+ * in a list if anybody wants to make use of NFSv4 COMPOUND
+ * operations and/or has a need for scatter/gather involving pages.
+ */
+struct xdr_buf {
+ struct kvec head[1], /* RPC header + non-page data */
+ tail[1]; /* Appended after page data */
+
+ struct bio_vec *bvec;
+ struct page ** pages; /* Array of pages */
+ unsigned int page_base, /* Start of page data */
+ page_len, /* Length of page data */
+ flags; /* Flags for data disposition */
+#define XDRBUF_READ 0x01 /* target of file read */
+#define XDRBUF_WRITE 0x02 /* source of file write */
+#define XDRBUF_SPARSE_PAGES 0x04 /* Page array is sparse */
+
+ unsigned int buflen, /* Total length of storage buffer */
+ len; /* Length of XDR encoded message */
+};
+
+static inline void
+xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
+{
+ buf->head[0].iov_base = start;
+ buf->head[0].iov_len = len;
+ buf->tail[0].iov_len = 0;
+ buf->pages = NULL;
+ buf->page_len = 0;
+ buf->flags = 0;
+ buf->len = 0;
+ buf->buflen = len;
+}
+
+/*
+ * pre-xdr'ed macros.
+ */
+
+#define xdr_zero cpu_to_be32(0)
+#define xdr_one cpu_to_be32(1)
+#define xdr_two cpu_to_be32(2)
+
+#define rpc_auth_null cpu_to_be32(RPC_AUTH_NULL)
+#define rpc_auth_unix cpu_to_be32(RPC_AUTH_UNIX)
+#define rpc_auth_short cpu_to_be32(RPC_AUTH_SHORT)
+#define rpc_auth_gss cpu_to_be32(RPC_AUTH_GSS)
+#define rpc_auth_tls cpu_to_be32(RPC_AUTH_TLS)
+
+#define rpc_call cpu_to_be32(RPC_CALL)
+#define rpc_reply cpu_to_be32(RPC_REPLY)
+
+#define rpc_msg_accepted cpu_to_be32(RPC_MSG_ACCEPTED)
+
+#define rpc_success cpu_to_be32(RPC_SUCCESS)
+#define rpc_prog_unavail cpu_to_be32(RPC_PROG_UNAVAIL)
+#define rpc_prog_mismatch cpu_to_be32(RPC_PROG_MISMATCH)
+#define rpc_proc_unavail cpu_to_be32(RPC_PROC_UNAVAIL)
+#define rpc_garbage_args cpu_to_be32(RPC_GARBAGE_ARGS)
+#define rpc_system_err cpu_to_be32(RPC_SYSTEM_ERR)
+#define rpc_drop_reply cpu_to_be32(RPC_DROP_REPLY)
+
+#define rpc_mismatch cpu_to_be32(RPC_MISMATCH)
+#define rpc_auth_error cpu_to_be32(RPC_AUTH_ERROR)
+
+#define rpc_auth_ok cpu_to_be32(RPC_AUTH_OK)
+#define rpc_autherr_badcred cpu_to_be32(RPC_AUTH_BADCRED)
+#define rpc_autherr_rejectedcred cpu_to_be32(RPC_AUTH_REJECTEDCRED)
+#define rpc_autherr_badverf cpu_to_be32(RPC_AUTH_BADVERF)
+#define rpc_autherr_rejectedverf cpu_to_be32(RPC_AUTH_REJECTEDVERF)
+#define rpc_autherr_tooweak cpu_to_be32(RPC_AUTH_TOOWEAK)
+#define rpcsec_gsserr_credproblem cpu_to_be32(RPCSEC_GSS_CREDPROBLEM)
+#define rpcsec_gsserr_ctxproblem cpu_to_be32(RPCSEC_GSS_CTXPROBLEM)
+
+/*
+ * Miscellaneous XDR helper functions
+ */
+__be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int len);
+__be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int len);
+__be32 *xdr_encode_string(__be32 *p, const char *s);
+__be32 *xdr_decode_string_inplace(__be32 *p, char **sp, unsigned int *lenp,
+ unsigned int maxlen);
+__be32 *xdr_encode_netobj(__be32 *p, const struct xdr_netobj *);
+__be32 *xdr_decode_netobj(__be32 *p, struct xdr_netobj *);
+
+void xdr_inline_pages(struct xdr_buf *, unsigned int,
+ struct page **, unsigned int, unsigned int);
+void xdr_terminate_string(const struct xdr_buf *, const u32);
+size_t xdr_buf_pagecount(const struct xdr_buf *buf);
+int xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp);
+void xdr_free_bvec(struct xdr_buf *buf);
+unsigned int xdr_buf_to_bvec(struct bio_vec *bvec, unsigned int bvec_size,
+ const struct xdr_buf *xdr);
+
+static inline __be32 *xdr_encode_array(__be32 *p, const void *s, unsigned int len)
+{
+ return xdr_encode_opaque(p, s, len);
+}
+
+/*
+ * Decode 64bit quantities (NFSv3 support)
+ */
+static inline __be32 *
+xdr_encode_hyper(__be32 *p, __u64 val)
+{
+ put_unaligned_be64(val, p);
+ return p + 2;
+}
+
+static inline __be32 *
+xdr_decode_hyper(__be32 *p, __u64 *valp)
+{
+ *valp = get_unaligned_be64(p);
+ return p + 2;
+}
+
+static inline __be32 *
+xdr_decode_opaque_fixed(__be32 *p, void *ptr, unsigned int len)
+{
+ memcpy(ptr, p, len);
+ return p + XDR_QUADLEN(len);
+}
+
+static inline void xdr_netobj_dup(struct xdr_netobj *dst,
+ struct xdr_netobj *src, gfp_t gfp_mask)
+{
+ dst->data = kmemdup(src->data, src->len, gfp_mask);
+ dst->len = src->len;
+}
+
+/*
+ * Adjust kvec to reflect end of xdr'ed data (RPC client XDR)
+ */
+static inline int
+xdr_adjust_iovec(struct kvec *iov, __be32 *p)
+{
+ return iov->iov_len = ((u8 *) p - (u8 *) iov->iov_base);
+}
+
+/*
+ * XDR buffer helper functions
+ */
+extern void xdr_buf_from_iov(const struct kvec *, struct xdr_buf *);
+extern int xdr_buf_subsegment(const struct xdr_buf *, struct xdr_buf *, unsigned int, unsigned int);
+extern void xdr_buf_trim(struct xdr_buf *, unsigned int);
+extern int read_bytes_from_xdr_buf(const struct xdr_buf *, unsigned int, void *, unsigned int);
+extern int write_bytes_to_xdr_buf(const struct xdr_buf *, unsigned int, void *, unsigned int);
+
+extern int xdr_encode_word(const struct xdr_buf *, unsigned int, u32);
+extern int xdr_decode_word(const struct xdr_buf *, unsigned int, u32 *);
+
+struct xdr_array2_desc;
+typedef int (*xdr_xcode_elem_t)(struct xdr_array2_desc *desc, void *elem);
+struct xdr_array2_desc {
+ unsigned int elem_size;
+ unsigned int array_len;
+ unsigned int array_maxlen;
+ xdr_xcode_elem_t xcode;
+};
+
+extern int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
+ struct xdr_array2_desc *desc);
+extern int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
+ struct xdr_array2_desc *desc);
+extern void _copy_from_pages(char *p, struct page **pages, size_t pgbase,
+ size_t len);
+
+/*
+ * Provide some simple tools for XDR buffer overflow-checking etc.
+ */
+struct xdr_stream {
+ __be32 *p; /* start of available buffer */
+ struct xdr_buf *buf; /* XDR buffer to read/write */
+
+ __be32 *end; /* end of available buffer space */
+ struct kvec *iov; /* pointer to the current kvec */
+ struct kvec scratch; /* Scratch buffer */
+ struct page **page_ptr; /* pointer to the current page */
+ void *page_kaddr; /* kmapped address of the current page */
+ unsigned int nwords; /* Remaining decode buffer length */
+
+ struct rpc_rqst *rqst; /* For debugging */
+};
+
+/*
+ * These are the xdr_stream style generic XDR encode and decode functions.
+ */
+typedef void (*kxdreproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
+ const void *obj);
+typedef int (*kxdrdproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
+ void *obj);
+
+extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf,
+ __be32 *p, struct rpc_rqst *rqst);
+extern void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
+ struct page **pages, struct rpc_rqst *rqst);
+extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
+extern int xdr_reserve_space_vec(struct xdr_stream *xdr, size_t nbytes);
+extern void __xdr_commit_encode(struct xdr_stream *xdr);
+extern void xdr_truncate_encode(struct xdr_stream *xdr, size_t len);
+extern void xdr_truncate_decode(struct xdr_stream *xdr, size_t len);
+extern int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen);
+extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,
+ unsigned int base, unsigned int len);
+extern unsigned int xdr_stream_pos(const struct xdr_stream *xdr);
+extern unsigned int xdr_page_pos(const struct xdr_stream *xdr);
+extern void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf,
+ __be32 *p, struct rpc_rqst *rqst);
+extern void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
+ struct page **pages, unsigned int len);
+extern void xdr_finish_decode(struct xdr_stream *xdr);
+extern __be32 *xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes);
+extern unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len);
+extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len);
+extern int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);
+extern void xdr_set_pagelen(struct xdr_stream *, unsigned int len);
+extern bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
+ unsigned int len);
+extern unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset,
+ unsigned int target, unsigned int length);
+extern unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset,
+ unsigned int length);
+
+/**
+ * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
+ * @xdr: pointer to xdr_stream struct
+ * @buf: pointer to an empty buffer
+ * @buflen: size of 'buf'
+ *
+ * The scratch buffer is used when decoding from an array of pages.
+ * If an xdr_inline_decode() call spans across page boundaries, then
+ * we copy the data into the scratch buffer in order to allow linear
+ * access.
+ */
+static inline void
+xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
+{
+ xdr->scratch.iov_base = buf;
+ xdr->scratch.iov_len = buflen;
+}
+
+/**
+ * xdr_set_scratch_page - Attach a scratch buffer for decoding data
+ * @xdr: pointer to xdr_stream struct
+ * @page: an anonymous page
+ *
+ * See xdr_set_scratch_buffer().
+ */
+static inline void
+xdr_set_scratch_page(struct xdr_stream *xdr, struct page *page)
+{
+ xdr_set_scratch_buffer(xdr, page_address(page), PAGE_SIZE);
+}
+
+/**
+ * xdr_reset_scratch_buffer - Clear scratch buffer information
+ * @xdr: pointer to xdr_stream struct
+ *
+ * See xdr_set_scratch_buffer().
+ */
+static inline void
+xdr_reset_scratch_buffer(struct xdr_stream *xdr)
+{
+ xdr_set_scratch_buffer(xdr, NULL, 0);
+}
+
+/**
+ * xdr_commit_encode - Ensure all data is written to xdr->buf
+ * @xdr: pointer to xdr_stream
+ *
+ * Handle encoding across page boundaries by giving the caller a
+ * temporary location to write to, then later copying the data into
+ * place. __xdr_commit_encode() does that copying.
+ */
+static inline void xdr_commit_encode(struct xdr_stream *xdr)
+{
+ if (unlikely(xdr->scratch.iov_len))
+ __xdr_commit_encode(xdr);
+}
+
+/**
+ * xdr_stream_remaining - Return the number of bytes remaining in the stream
+ * @xdr: pointer to struct xdr_stream
+ *
+ * Return value:
+ * Number of bytes remaining in @xdr before xdr->end
+ */
+static inline size_t
+xdr_stream_remaining(const struct xdr_stream *xdr)
+{
+ return xdr->nwords << 2;
+}
+
+ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr,
+ size_t size);
+ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
+ size_t maxlen, gfp_t gfp_flags);
+ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str,
+ size_t size);
+ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
+ size_t maxlen, gfp_t gfp_flags);
+ssize_t xdr_stream_decode_opaque_auth(struct xdr_stream *xdr, u32 *flavor,
+ void **body, unsigned int *body_len);
+ssize_t xdr_stream_encode_opaque_auth(struct xdr_stream *xdr, u32 flavor,
+ void *body, unsigned int body_len);
+
+/**
+ * xdr_align_size - Calculate padded size of an object
+ * @n: Size of an object being XDR encoded (in bytes)
+ *
+ * Return value:
+ * Size (in bytes) of the object including xdr padding
+ */
+static inline size_t
+xdr_align_size(size_t n)
+{
+ const size_t mask = XDR_UNIT - 1;
+
+ return (n + mask) & ~mask;
+}
+
+/**
+ * xdr_pad_size - Calculate size of an object's pad
+ * @n: Size of an object being XDR encoded (in bytes)
+ *
+ * This implementation avoids the need for conditional
+ * branches or modulo division.
+ *
+ * Return value:
+ * Size (in bytes) of the needed XDR pad
+ */
+static inline size_t xdr_pad_size(size_t n)
+{
+ return xdr_align_size(n) - n;
+}
+
+/**
+ * xdr_stream_encode_item_present - Encode a "present" list item
+ * @xdr: pointer to xdr_stream
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline ssize_t xdr_stream_encode_item_present(struct xdr_stream *xdr)
+{
+ const size_t len = XDR_UNIT;
+ __be32 *p = xdr_reserve_space(xdr, len);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ *p = xdr_one;
+ return len;
+}
+
+/**
+ * xdr_stream_encode_item_absent - Encode a "not present" list item
+ * @xdr: pointer to xdr_stream
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline int xdr_stream_encode_item_absent(struct xdr_stream *xdr)
+{
+ const size_t len = XDR_UNIT;
+ __be32 *p = xdr_reserve_space(xdr, len);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ *p = xdr_zero;
+ return len;
+}
+
+/**
+ * xdr_encode_bool - Encode a boolean item
+ * @p: address in a buffer into which to encode
+ * @n: boolean value to encode
+ *
+ * Return value:
+ * Address of item following the encoded boolean
+ */
+static inline __be32 *xdr_encode_bool(__be32 *p, u32 n)
+{
+ *p++ = n ? xdr_one : xdr_zero;
+ return p;
+}
+
+/**
+ * xdr_stream_encode_bool - Encode a boolean item
+ * @xdr: pointer to xdr_stream
+ * @n: boolean value to encode
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline int xdr_stream_encode_bool(struct xdr_stream *xdr, __u32 n)
+{
+ const size_t len = XDR_UNIT;
+ __be32 *p = xdr_reserve_space(xdr, len);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ xdr_encode_bool(p, n);
+ return len;
+}
+
+/**
+ * xdr_stream_encode_u32 - Encode a 32-bit integer
+ * @xdr: pointer to xdr_stream
+ * @n: integer to encode
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_encode_u32(struct xdr_stream *xdr, __u32 n)
+{
+ const size_t len = sizeof(n);
+ __be32 *p = xdr_reserve_space(xdr, len);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ *p = cpu_to_be32(n);
+ return len;
+}
+
+/**
+ * xdr_stream_encode_be32 - Encode a big-endian 32-bit integer
+ * @xdr: pointer to xdr_stream
+ * @n: integer to encode
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_encode_be32(struct xdr_stream *xdr, __be32 n)
+{
+ const size_t len = sizeof(n);
+ __be32 *p = xdr_reserve_space(xdr, len);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ *p = n;
+ return len;
+}
+
+/**
+ * xdr_stream_encode_u64 - Encode a 64-bit integer
+ * @xdr: pointer to xdr_stream
+ * @n: 64-bit integer to encode
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_encode_u64(struct xdr_stream *xdr, __u64 n)
+{
+ const size_t len = sizeof(n);
+ __be32 *p = xdr_reserve_space(xdr, len);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ xdr_encode_hyper(p, n);
+ return len;
+}
+
+/**
+ * xdr_stream_encode_opaque_inline - Encode opaque xdr data
+ * @xdr: pointer to xdr_stream
+ * @ptr: pointer to void pointer
+ * @len: size of object
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_encode_opaque_inline(struct xdr_stream *xdr, void **ptr, size_t len)
+{
+ size_t count = sizeof(__u32) + xdr_align_size(len);
+ __be32 *p = xdr_reserve_space(xdr, count);
+
+ if (unlikely(!p)) {
+ *ptr = NULL;
+ return -EMSGSIZE;
+ }
+ xdr_encode_opaque(p, NULL, len);
+ *ptr = ++p;
+ return count;
+}
+
+/**
+ * xdr_stream_encode_opaque_fixed - Encode fixed length opaque xdr data
+ * @xdr: pointer to xdr_stream
+ * @ptr: pointer to opaque data object
+ * @len: size of object pointed to by @ptr
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_encode_opaque_fixed(struct xdr_stream *xdr, const void *ptr, size_t len)
+{
+ __be32 *p = xdr_reserve_space(xdr, len);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ xdr_encode_opaque_fixed(p, ptr, len);
+ return xdr_align_size(len);
+}
+
+/**
+ * xdr_stream_encode_opaque - Encode variable length opaque xdr data
+ * @xdr: pointer to xdr_stream
+ * @ptr: pointer to opaque data object
+ * @len: size of object pointed to by @ptr
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_encode_opaque(struct xdr_stream *xdr, const void *ptr, size_t len)
+{
+ size_t count = sizeof(__u32) + xdr_align_size(len);
+ __be32 *p = xdr_reserve_space(xdr, count);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ xdr_encode_opaque(p, ptr, len);
+ return count;
+}
+
+/**
+ * xdr_stream_encode_uint32_array - Encode variable length array of integers
+ * @xdr: pointer to xdr_stream
+ * @array: array of integers
+ * @array_size: number of elements in @array
+ *
+ * Return values:
+ * On success, returns length in bytes of XDR buffer consumed
+ * %-EMSGSIZE on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_encode_uint32_array(struct xdr_stream *xdr,
+ const __u32 *array, size_t array_size)
+{
+ ssize_t ret = (array_size+1) * sizeof(__u32);
+ __be32 *p = xdr_reserve_space(xdr, ret);
+
+ if (unlikely(!p))
+ return -EMSGSIZE;
+ *p++ = cpu_to_be32(array_size);
+ for (; array_size > 0; p++, array++, array_size--)
+ *p = cpu_to_be32p(array);
+ return ret;
+}
+
+/**
+ * xdr_item_is_absent - symbolically handle XDR discriminators
+ * @p: pointer to undecoded discriminator
+ *
+ * Return values:
+ * %true if the following XDR item is absent
+ * %false if the following XDR item is present
+ */
+static inline bool xdr_item_is_absent(const __be32 *p)
+{
+ return *p == xdr_zero;
+}
+
+/**
+ * xdr_item_is_present - symbolically handle XDR discriminators
+ * @p: pointer to undecoded discriminator
+ *
+ * Return values:
+ * %true if the following XDR item is present
+ * %false if the following XDR item is absent
+ */
+static inline bool xdr_item_is_present(const __be32 *p)
+{
+ return *p != xdr_zero;
+}
+
+/**
+ * xdr_stream_decode_bool - Decode a boolean
+ * @xdr: pointer to xdr_stream
+ * @ptr: pointer to a u32 in which to store the result
+ *
+ * Return values:
+ * %0 on success
+ * %-EBADMSG on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_decode_bool(struct xdr_stream *xdr, __u32 *ptr)
+{
+ const size_t count = sizeof(*ptr);
+ __be32 *p = xdr_inline_decode(xdr, count);
+
+ if (unlikely(!p))
+ return -EBADMSG;
+ *ptr = (*p != xdr_zero);
+ return 0;
+}
+
+/**
+ * xdr_stream_decode_u32 - Decode a 32-bit integer
+ * @xdr: pointer to xdr_stream
+ * @ptr: location to store integer
+ *
+ * Return values:
+ * %0 on success
+ * %-EBADMSG on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_decode_u32(struct xdr_stream *xdr, __u32 *ptr)
+{
+ const size_t count = sizeof(*ptr);
+ __be32 *p = xdr_inline_decode(xdr, count);
+
+ if (unlikely(!p))
+ return -EBADMSG;
+ *ptr = be32_to_cpup(p);
+ return 0;
+}
+
+/**
+ * xdr_stream_decode_u64 - Decode a 64-bit integer
+ * @xdr: pointer to xdr_stream
+ * @ptr: location to store 64-bit integer
+ *
+ * Return values:
+ * %0 on success
+ * %-EBADMSG on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_decode_u64(struct xdr_stream *xdr, __u64 *ptr)
+{
+ const size_t count = sizeof(*ptr);
+ __be32 *p = xdr_inline_decode(xdr, count);
+
+ if (unlikely(!p))
+ return -EBADMSG;
+ xdr_decode_hyper(p, ptr);
+ return 0;
+}
+
+/**
+ * xdr_stream_decode_opaque_fixed - Decode fixed length opaque xdr data
+ * @xdr: pointer to xdr_stream
+ * @ptr: location to store data
+ * @len: size of buffer pointed to by @ptr
+ *
+ * Return values:
+ * On success, returns size of object stored in @ptr
+ * %-EBADMSG on XDR buffer overflow
+ */
+static inline ssize_t
+xdr_stream_decode_opaque_fixed(struct xdr_stream *xdr, void *ptr, size_t len)
+{
+ __be32 *p = xdr_inline_decode(xdr, len);
+
+ if (unlikely(!p))
+ return -EBADMSG;
+ xdr_decode_opaque_fixed(p, ptr, len);
+ return len;
+}
+
+/**
+ * xdr_stream_decode_opaque_inline - Decode variable length opaque xdr data
+ * @xdr: pointer to xdr_stream
+ * @ptr: location to store pointer to opaque data
+ * @maxlen: maximum acceptable object size
+ *
+ * Note: the pointer stored in @ptr cannot be assumed valid after the XDR
+ * buffer has been destroyed, or even after calling xdr_inline_decode()
+ * on @xdr. It is therefore expected that the object it points to should
+ * be processed immediately.
+ *
+ * Return values:
+ * On success, returns size of object stored in *@ptr
+ * %-EBADMSG on XDR buffer overflow
+ * %-EMSGSIZE if the size of the object would exceed @maxlen
+ */
+static inline ssize_t
+xdr_stream_decode_opaque_inline(struct xdr_stream *xdr, void **ptr, size_t maxlen)
+{
+ __be32 *p;
+ __u32 len;
+
+ *ptr = NULL;
+ if (unlikely(xdr_stream_decode_u32(xdr, &len) < 0))
+ return -EBADMSG;
+ if (len != 0) {
+ p = xdr_inline_decode(xdr, len);
+ if (unlikely(!p))
+ return -EBADMSG;
+ if (unlikely(len > maxlen))
+ return -EMSGSIZE;
+ *ptr = p;
+ }
+ return len;
+}
+
+/**
+ * xdr_stream_decode_uint32_array - Decode variable length array of integers
+ * @xdr: pointer to xdr_stream
+ * @array: location to store the integer array or NULL
+ * @array_size: number of elements to store
+ *
+ * Return values:
+ * On success, returns number of elements stored in @array
+ * %-EBADMSG on XDR buffer overflow
+ * %-EMSGSIZE if the size of the array exceeds @array_size
+ */
+static inline ssize_t
+xdr_stream_decode_uint32_array(struct xdr_stream *xdr,
+ __u32 *array, size_t array_size)
+{
+ __be32 *p;
+ __u32 len;
+ ssize_t retval;
+
+ if (unlikely(xdr_stream_decode_u32(xdr, &len) < 0))
+ return -EBADMSG;
+ if (U32_MAX >= SIZE_MAX / sizeof(*p) && len > SIZE_MAX / sizeof(*p))
+ return -EBADMSG;
+ p = xdr_inline_decode(xdr, len * sizeof(*p));
+ if (unlikely(!p))
+ return -EBADMSG;
+ if (array == NULL)
+ return len;
+ if (len <= array_size) {
+ if (len < array_size)
+ memset(array+len, 0, (array_size-len)*sizeof(*array));
+ array_size = len;
+ retval = len;
+ } else
+ retval = -EMSGSIZE;
+ for (; array_size > 0; p++, array++, array_size--)
+ *array = be32_to_cpup(p);
+ return retval;
+}
+
+#endif /* _SUNRPC_XDR_H_ */