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