include/linux/sunrpc/xdr.h

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