include/linux/sunrpc/xdr.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * XDR standard data types and function declarations
   4  *
   5  * Copyright (C) 1995-1997 Olaf Kirch <okir@monad.swb.de>
   6  *
   7  * Based on:
   8  *   RFC 4506 "XDR: External Data Representation Standard", May 2006
   9  */
  10
  11 #ifndef _SUNRPC_XDR_H_
  12 #define _SUNRPC_XDR_H_
  13
  14 #ifdef __KERNEL__
  15
  16 #include <linux/uio.h>
  17 #include <asm/byteorder.h>
  18 #include <asm/unaligned.h>
  19 #include <linux/scatterlist.h>
  20
  21 struct rpc_rqst;
  22
  23 /*
  24  * Buffer adjustment
  25  */
  26 #define XDR_QUADLEN(l)          (((l) + 3) >> 2)
  27
  28 /*
  29  * Generic opaque `network object.' At the kernel level, this type
  30  * is used only by lockd.
  31  */
  32 #define XDR_MAX_NETOBJ          1024
  33 struct xdr_netobj {
  34         unsigned int            len;
  35         u8 *                    data;
  36 };
  37
  38 /*
  39  * Basic structure for transmission/reception of a client XDR message.
  40  * Features a header (for a linear buffer containing RPC headers
  41  * and the data payload for short messages), and then an array of
  42  * pages.
  43  * The tail iovec allows you to append data after the page array. Its
  44  * main interest is for appending padding to the pages in order to
  45  * satisfy the int_32-alignment requirements in RFC1832.
  46  *
  47  * For the future, we might want to string several of these together
  48  * in a list if anybody wants to make use of NFSv4 COMPOUND
  49  * operations and/or has a need for scatter/gather involving pages.
  50  */
  51 struct xdr_buf {
  52         struct kvec     head[1],        /* RPC header + non-page data */
  53                         tail[1];        /* Appended after page data */
  54
  55         struct page **  pages;          /* Array of pages */
  56         unsigned int    page_base,      /* Start of page data */
  57                         page_len,       /* Length of page data */
  58                         flags;          /* Flags for data disposition */
  59 #define XDRBUF_READ             0x01            /* target of file read */
  60 #define XDRBUF_WRITE            0x02            /* source of file write */
  61
  62         unsigned int    buflen,         /* Total length of storage buffer */
  63                         len;            /* Length of XDR encoded message */
  64 };
  65
  66 static inline void
  67 xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
  68 {
  69         buf->head[0].iov_base = start;
  70         buf->head[0].iov_len = len;
  71         buf->tail[0].iov_len = 0;
  72         buf->page_len = 0;
  73         buf->flags = 0;
  74         buf->len = 0;
  75         buf->buflen = len;
  76 }
  77
  78 /*
  79  * pre-xdr'ed macros.
  80  */
  81
  82 #define xdr_zero        cpu_to_be32(0)
  83 #define xdr_one         cpu_to_be32(1)
  84 #define xdr_two         cpu_to_be32(2)
  85
  86 #define rpc_success             cpu_to_be32(RPC_SUCCESS)
  87 #define rpc_prog_unavail        cpu_to_be32(RPC_PROG_UNAVAIL)
  88 #define rpc_prog_mismatch       cpu_to_be32(RPC_PROG_MISMATCH)
  89 #define rpc_proc_unavail        cpu_to_be32(RPC_PROC_UNAVAIL)
  90 #define rpc_garbage_args        cpu_to_be32(RPC_GARBAGE_ARGS)
  91 #define rpc_system_err          cpu_to_be32(RPC_SYSTEM_ERR)
  92 #define rpc_drop_reply          cpu_to_be32(RPC_DROP_REPLY)
  93
  94 #define rpc_auth_ok             cpu_to_be32(RPC_AUTH_OK)
  95 #define rpc_autherr_badcred     cpu_to_be32(RPC_AUTH_BADCRED)
  96 #define rpc_autherr_rejectedcred cpu_to_be32(RPC_AUTH_REJECTEDCRED)
  97 #define rpc_autherr_badverf     cpu_to_be32(RPC_AUTH_BADVERF)
  98 #define rpc_autherr_rejectedverf cpu_to_be32(RPC_AUTH_REJECTEDVERF)
  99 #define rpc_autherr_tooweak     cpu_to_be32(RPC_AUTH_TOOWEAK)
 100 #define rpcsec_gsserr_credproblem       cpu_to_be32(RPCSEC_GSS_CREDPROBLEM)
 101 #define rpcsec_gsserr_ctxproblem        cpu_to_be32(RPCSEC_GSS_CTXPROBLEM)
 102 #define rpc_autherr_oldseqnum   cpu_to_be32(101)
 103
 104 /*
 105  * Miscellaneous XDR helper functions
 106  */
 107 __be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int len);
 108 __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int len);
 109 __be32 *xdr_encode_string(__be32 *p, const char *s);
 110 __be32 *xdr_decode_string_inplace(__be32 *p, char **sp, unsigned int *lenp,
 111                         unsigned int maxlen);
 112 __be32 *xdr_encode_netobj(__be32 *p, const struct xdr_netobj *);
 113 __be32 *xdr_decode_netobj(__be32 *p, struct xdr_netobj *);
 114
 115 void    xdr_inline_pages(struct xdr_buf *, unsigned int,
 116                          struct page **, unsigned int, unsigned int);
 117 void    xdr_terminate_string(struct xdr_buf *, const u32);
 118
 119 static inline __be32 *xdr_encode_array(__be32 *p, const void *s, unsigned int len)
 120 {
 121         return xdr_encode_opaque(p, s, len);
 122 }
 123
 124 /*
 125  * Decode 64bit quantities (NFSv3 support)
 126  */
 127 static inline __be32 *
 128 xdr_encode_hyper(__be32 *p, __u64 val)
 129 {
 130         put_unaligned_be64(val, p);
 131         return p + 2;
 132 }
 133
 134 static inline __be32 *
 135 xdr_decode_hyper(__be32 *p, __u64 *valp)
 136 {
 137         *valp = get_unaligned_be64(p);
 138         return p + 2;
 139 }
 140
 141 static inline __be32 *
 142 xdr_decode_opaque_fixed(__be32 *p, void *ptr, unsigned int len)
 143 {
 144         memcpy(ptr, p, len);
 145         return p + XDR_QUADLEN(len);
 146 }
 147
 148 /*
 149  * Adjust kvec to reflect end of xdr'ed data (RPC client XDR)
 150  */
 151 static inline int
 152 xdr_adjust_iovec(struct kvec *iov, __be32 *p)
 153 {
 154         return iov->iov_len = ((u8 *) p - (u8 *) iov->iov_base);
 155 }
 156
 157 /*
 158  * XDR buffer helper functions
 159  */
 160 extern void xdr_shift_buf(struct xdr_buf *, size_t);
 161 extern void xdr_buf_from_iov(struct kvec *, struct xdr_buf *);
 162 extern int xdr_buf_subsegment(struct xdr_buf *, struct xdr_buf *, unsigned int, unsigned int);
 163 extern void xdr_buf_trim(struct xdr_buf *, unsigned int);
 164 extern int xdr_buf_read_netobj(struct xdr_buf *, struct xdr_netobj *, unsigned int);
 165 extern int read_bytes_from_xdr_buf(struct xdr_buf *, unsigned int, void *, unsigned int);
 166 extern int write_bytes_to_xdr_buf(struct xdr_buf *, unsigned int, void *, unsigned int);
 167
 168 /*
 169  * Helper structure for copying from an sk_buff.
 170  */
 171 struct xdr_skb_reader {
 172         struct sk_buff  *skb;
 173         unsigned int    offset;
 174         size_t          count;
 175         __wsum          csum;
 176 };
 177
 178 typedef size_t (*xdr_skb_read_actor)(struct xdr_skb_reader *desc, void *to, size_t len);
 179
 180 size_t xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len);
 181 extern int csum_partial_copy_to_xdr(struct xdr_buf *, struct sk_buff *);
 182 extern ssize_t xdr_partial_copy_from_skb(struct xdr_buf *, unsigned int,
 183                 struct xdr_skb_reader *, xdr_skb_read_actor);
 184
 185 extern int xdr_encode_word(struct xdr_buf *, unsigned int, u32);
 186 extern int xdr_decode_word(struct xdr_buf *, unsigned int, u32 *);
 187
 188 struct xdr_array2_desc;
 189 typedef int (*xdr_xcode_elem_t)(struct xdr_array2_desc *desc, void *elem);
 190 struct xdr_array2_desc {
 191         unsigned int elem_size;
 192         unsigned int array_len;
 193         unsigned int array_maxlen;
 194         xdr_xcode_elem_t xcode;
 195 };
 196
 197 extern int xdr_decode_array2(struct xdr_buf *buf, unsigned int base,
 198                              struct xdr_array2_desc *desc);
 199 extern int xdr_encode_array2(struct xdr_buf *buf, unsigned int base,
 200                              struct xdr_array2_desc *desc);
 201 extern void _copy_from_pages(char *p, struct page **pages, size_t pgbase,
 202                              size_t len);
 203
 204 /*
 205  * Provide some simple tools for XDR buffer overflow-checking etc.
 206  */
 207 struct xdr_stream {
 208         __be32 *p;              /* start of available buffer */
 209         struct xdr_buf *buf;    /* XDR buffer to read/write */
 210
 211         __be32 *end;            /* end of available buffer space */
 212         struct kvec *iov;       /* pointer to the current kvec */
 213         struct kvec scratch;    /* Scratch buffer */
 214         struct page **page_ptr; /* pointer to the current page */
 215         unsigned int nwords;    /* Remaining decode buffer length */
 216 };
 217
 218 /*
 219  * These are the xdr_stream style generic XDR encode and decode functions.
 220  */
 221 typedef void    (*kxdreproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
 222                 const void *obj);
 223 typedef int     (*kxdrdproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
 224                 void *obj);
 225
 226 extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);
 227 extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
 228 extern void xdr_commit_encode(struct xdr_stream *xdr);
 229 extern void xdr_truncate_encode(struct xdr_stream *xdr, size_t len);
 230 extern int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen);
 231 extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,
 232                 unsigned int base, unsigned int len);
 233 extern unsigned int xdr_stream_pos(const struct xdr_stream *xdr);
 234 extern void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);
 235 extern void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
 236                 struct page **pages, unsigned int len);
 237 extern void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen);
 238 extern __be32 *xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes);
 239 extern unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len);
 240 extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len);
 241 extern int xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);
 242
 243 /**
 244  * xdr_stream_remaining - Return the number of bytes remaining in the stream
 245  * @xdr: pointer to struct xdr_stream
 246  *
 247  * Return value:
 248  *   Number of bytes remaining in @xdr before xdr->end
 249  */
 250 static inline size_t
 251 xdr_stream_remaining(const struct xdr_stream *xdr)
 252 {
 253         return xdr->nwords << 2;
 254 }
 255
 256 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
 257                 size_t maxlen, gfp_t gfp_flags);
 258 /**
 259  * xdr_align_size - Calculate padded size of an object
 260  * @n: Size of an object being XDR encoded (in bytes)
 261  *
 262  * Return value:
 263  *   Size (in bytes) of the object including xdr padding
 264  */
 265 static inline size_t
 266 xdr_align_size(size_t n)
 267 {
 268         const size_t mask = sizeof(__u32) - 1;
 269
 270         return (n + mask) & ~mask;
 271 }
 272
 273 /**
 274  * xdr_stream_encode_u32 - Encode a 32-bit integer
 275  * @xdr: pointer to xdr_stream
 276  * @n: integer to encode
 277  *
 278  * Return values:
 279  *   On success, returns length in bytes of XDR buffer consumed
 280  *   %-EMSGSIZE on XDR buffer overflow
 281  */
 282 static inline ssize_t
 283 xdr_stream_encode_u32(struct xdr_stream *xdr, __u32 n)
 284 {
 285         const size_t len = sizeof(n);
 286         __be32 *p = xdr_reserve_space(xdr, len);
 287
 288         if (unlikely(!p))
 289                 return -EMSGSIZE;
 290         *p = cpu_to_be32(n);
 291         return len;
 292 }
 293
 294 /**
 295  * xdr_stream_encode_u64 - Encode a 64-bit integer
 296  * @xdr: pointer to xdr_stream
 297  * @n: 64-bit integer to encode
 298  *
 299  * Return values:
 300  *   On success, returns length in bytes of XDR buffer consumed
 301  *   %-EMSGSIZE on XDR buffer overflow
 302  */
 303 static inline ssize_t
 304 xdr_stream_encode_u64(struct xdr_stream *xdr, __u64 n)
 305 {
 306         const size_t len = sizeof(n);
 307         __be32 *p = xdr_reserve_space(xdr, len);
 308
 309         if (unlikely(!p))
 310                 return -EMSGSIZE;
 311         xdr_encode_hyper(p, n);
 312         return len;
 313 }
 314
 315 /**
 316  * xdr_stream_encode_opaque_fixed - Encode fixed length opaque xdr data
 317  * @xdr: pointer to xdr_stream
 318  * @ptr: pointer to opaque data object
 319  * @len: size of object pointed to by @ptr
 320  *
 321  * Return values:
 322  *   On success, returns length in bytes of XDR buffer consumed
 323  *   %-EMSGSIZE on XDR buffer overflow
 324  */
 325 static inline ssize_t
 326 xdr_stream_encode_opaque_fixed(struct xdr_stream *xdr, const void *ptr, size_t len)
 327 {
 328         __be32 *p = xdr_reserve_space(xdr, len);
 329
 330         if (unlikely(!p))
 331                 return -EMSGSIZE;
 332         xdr_encode_opaque_fixed(p, ptr, len);
 333         return xdr_align_size(len);
 334 }
 335
 336 /**
 337  * xdr_stream_encode_opaque - Encode variable length opaque xdr data
 338  * @xdr: pointer to xdr_stream
 339  * @ptr: pointer to opaque data object
 340  * @len: size of object pointed to by @ptr
 341  *
 342  * Return values:
 343  *   On success, returns length in bytes of XDR buffer consumed
 344  *   %-EMSGSIZE on XDR buffer overflow
 345  */
 346 static inline ssize_t
 347 xdr_stream_encode_opaque(struct xdr_stream *xdr, const void *ptr, size_t len)
 348 {
 349         size_t count = sizeof(__u32) + xdr_align_size(len);
 350         __be32 *p = xdr_reserve_space(xdr, count);
 351
 352         if (unlikely(!p))
 353                 return -EMSGSIZE;
 354         xdr_encode_opaque(p, ptr, len);
 355         return count;
 356 }
 357
 358 /**
 359  * xdr_stream_decode_u32 - Decode a 32-bit integer
 360  * @xdr: pointer to xdr_stream
 361  * @ptr: location to store integer
 362  *
 363  * Return values:
 364  *   %0 on success
 365  *   %-EBADMSG on XDR buffer overflow
 366  */
 367 static inline ssize_t
 368 xdr_stream_decode_u32(struct xdr_stream *xdr, __u32 *ptr)
 369 {
 370         const size_t count = sizeof(*ptr);
 371         __be32 *p = xdr_inline_decode(xdr, count);
 372
 373         if (unlikely(!p))
 374                 return -EBADMSG;
 375         *ptr = be32_to_cpup(p);
 376         return 0;
 377 }
 378
 379 /**
 380  * xdr_stream_decode_opaque_fixed - Decode fixed length opaque xdr data
 381  * @xdr: pointer to xdr_stream
 382  * @ptr: location to store data
 383  * @len: size of buffer pointed to by @ptr
 384  *
 385  * Return values:
 386  *   On success, returns size of object stored in @ptr
 387  *   %-EBADMSG on XDR buffer overflow
 388  */
 389 static inline ssize_t
 390 xdr_stream_decode_opaque_fixed(struct xdr_stream *xdr, void *ptr, size_t len)
 391 {
 392         __be32 *p = xdr_inline_decode(xdr, len);
 393
 394         if (unlikely(!p))
 395                 return -EBADMSG;
 396         xdr_decode_opaque_fixed(p, ptr, len);
 397         return len;
 398 }
 399
 400 /**
 401  * xdr_stream_decode_opaque_inline - Decode variable length opaque xdr data
 402  * @xdr: pointer to xdr_stream
 403  * @ptr: location to store pointer to opaque data
 404  * @maxlen: maximum acceptable object size
 405  *
 406  * Note: the pointer stored in @ptr cannot be assumed valid after the XDR
 407  * buffer has been destroyed, or even after calling xdr_inline_decode()
 408  * on @xdr. It is therefore expected that the object it points to should
 409  * be processed immediately.
 410  *
 411  * Return values:
 412  *   On success, returns size of object stored in *@ptr
 413  *   %-EBADMSG on XDR buffer overflow
 414  *   %-EMSGSIZE if the size of the object would exceed @maxlen
 415  */
 416 static inline ssize_t
 417 xdr_stream_decode_opaque_inline(struct xdr_stream *xdr, void **ptr, size_t maxlen)
 418 {
 419         __be32 *p;
 420         __u32 len;
 421
 422         *ptr = NULL;
 423         if (unlikely(xdr_stream_decode_u32(xdr, &len) < 0))
 424                 return -EBADMSG;
 425         if (len != 0) {
 426                 p = xdr_inline_decode(xdr, len);
 427                 if (unlikely(!p))
 428                         return -EBADMSG;
 429                 if (unlikely(len > maxlen))
 430                         return -EMSGSIZE;
 431                 *ptr = p;
 432         }
 433         return len;
 434 }
 435 #endif /* __KERNEL__ */
 436
 437 #endif /* _SUNRPC_XDR_H_ */