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