net/irda/parameters.c

   1 /*********************************************************************
   2  *
   3  * Filename:      parameters.c
   4  * Version:       1.0
   5  * Description:   A more general way to handle (pi,pl,pv) parameters
   6  * Status:        Experimental.
   7  * Author:        Dag Brattli <dagb@cs.uit.no>
   8  * Created at:    Mon Jun  7 10:25:11 1999
   9  * Modified at:   Sun Jan 30 14:08:39 2000
  10  * Modified by:   Dag Brattli <dagb@cs.uit.no>
  11  *
  12  *     Copyright (c) 1999-2000 Dag Brattli, All Rights Reserved.
  13  *
  14  *     This program is free software; you can redistribute it and/or
  15  *     modify it under the terms of the GNU General Public License as
  16  *     published by the Free Software Foundation; either version 2 of
  17  *     the License, or (at your option) any later version.
  18  *
  19  *     This program is distributed in the hope that it will be useful,
  20  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  22  *     GNU General Public License for more details.
  23  *
  24  *     You should have received a copy of the GNU General Public License
  25  *     along with this program; if not, see <http://www.gnu.org/licenses/>.
  26  *
  27  ********************************************************************/
  28
  29 #include <linux/types.h>
  30 #include <linux/module.h>
  31
  32 #include <asm/unaligned.h>
  33 #include <asm/byteorder.h>
  34
  35 #include <net/irda/irda.h>
  36 #include <net/irda/parameters.h>
  37
  38 static int irda_extract_integer(void *self, __u8 *buf, int len, __u8 pi,
  39                                 PV_TYPE type, PI_HANDLER func);
  40 static int irda_extract_string(void *self, __u8 *buf, int len, __u8 pi,
  41                                PV_TYPE type, PI_HANDLER func);
  42 static int irda_extract_octseq(void *self, __u8 *buf, int len, __u8 pi,
  43                                PV_TYPE type, PI_HANDLER func);
  44 static int irda_extract_no_value(void *self, __u8 *buf, int len, __u8 pi,
  45                                  PV_TYPE type, PI_HANDLER func);
  46
  47 static int irda_insert_integer(void *self, __u8 *buf, int len, __u8 pi,
  48                                PV_TYPE type, PI_HANDLER func);
  49 static int irda_insert_no_value(void *self, __u8 *buf, int len, __u8 pi,
  50                                 PV_TYPE type, PI_HANDLER func);
  51
  52 static int irda_param_unpack(__u8 *buf, char *fmt, ...);
  53
  54 /* Parameter value call table. Must match PV_TYPE */
  55 static const PV_HANDLER pv_extract_table[] = {
  56         irda_extract_integer, /* Handler for any length integers */
  57         irda_extract_integer, /* Handler for 8  bits integers */
  58         irda_extract_integer, /* Handler for 16 bits integers */
  59         irda_extract_string,  /* Handler for strings */
  60         irda_extract_integer, /* Handler for 32 bits integers */
  61         irda_extract_octseq,  /* Handler for octet sequences */
  62         irda_extract_no_value /* Handler for no value parameters */
  63 };
  64
  65 static const PV_HANDLER pv_insert_table[] = {
  66         irda_insert_integer, /* Handler for any length integers */
  67         irda_insert_integer, /* Handler for 8  bits integers */
  68         irda_insert_integer, /* Handler for 16 bits integers */
  69         NULL,                /* Handler for strings */
  70         irda_insert_integer, /* Handler for 32 bits integers */
  71         NULL,                /* Handler for octet sequences */
  72         irda_insert_no_value /* Handler for no value parameters */
  73 };
  74
  75 /*
  76  * Function irda_insert_no_value (self, buf, len, pi, type, func)
  77  */
  78 static int irda_insert_no_value(void *self, __u8 *buf, int len, __u8 pi,
  79                                 PV_TYPE type, PI_HANDLER func)
  80 {
  81         irda_param_t p;
  82         int ret;
  83
  84         p.pi = pi;
  85         p.pl = 0;
  86
  87         /* Call handler for this parameter */
  88         ret = (*func)(self, &p, PV_GET);
  89
  90         /* Extract values anyway, since handler may need them */
  91         irda_param_pack(buf, "bb", p.pi, p.pl);
  92
  93         if (ret < 0)
  94                 return ret;
  95
  96         return 2; /* Inserted pl+2 bytes */
  97 }
  98
  99 /*
 100  * Function irda_extract_no_value (self, buf, len, type, func)
 101  *
 102  *    Extracts a parameter without a pv field (pl=0)
 103  *
 104  */
 105 static int irda_extract_no_value(void *self, __u8 *buf, int len, __u8 pi,
 106                                  PV_TYPE type, PI_HANDLER func)
 107 {
 108         irda_param_t p;
 109         int ret;
 110
 111         /* Extract values anyway, since handler may need them */
 112         irda_param_unpack(buf, "bb", &p.pi, &p.pl);
 113
 114         /* Call handler for this parameter */
 115         ret = (*func)(self, &p, PV_PUT);
 116
 117         if (ret < 0)
 118                 return ret;
 119
 120         return 2; /* Extracted pl+2 bytes */
 121 }
 122
 123 /*
 124  * Function irda_insert_integer (self, buf, len, pi, type, func)
 125  */
 126 static int irda_insert_integer(void *self, __u8 *buf, int len, __u8 pi,
 127                                PV_TYPE type, PI_HANDLER func)
 128 {
 129         irda_param_t p;
 130         int n = 0;
 131         int err;
 132
 133         p.pi = pi;             /* In case handler needs to know */
 134         p.pl = type & PV_MASK; /* The integer type codes the length as well */
 135         p.pv.i = 0;            /* Clear value */
 136
 137         /* Call handler for this parameter */
 138         err = (*func)(self, &p, PV_GET);
 139         if (err < 0)
 140                 return err;
 141
 142         /*
 143          * If parameter length is still 0, then (1) this is an any length
 144          * integer, and (2) the handler function does not care which length
 145          * we choose to use, so we pick the one the gives the fewest bytes.
 146          */
 147         if (p.pl == 0) {
 148                 if (p.pv.i < 0xff) {
 149                         pr_debug("%s(), using 1 byte\n", __func__);
 150                         p.pl = 1;
 151                 } else if (p.pv.i < 0xffff) {
 152                         pr_debug("%s(), using 2 bytes\n", __func__);
 153                         p.pl = 2;
 154                 } else {
 155                         pr_debug("%s(), using 4 bytes\n", __func__);
 156                         p.pl = 4; /* Default length */
 157                 }
 158         }
 159         /* Check if buffer is long enough for insertion */
 160         if (len < (2+p.pl)) {
 161                 net_warn_ratelimited("%s: buffer too short for insertion!\n",
 162                                      __func__);
 163                 return -1;
 164         }
 165         pr_debug("%s(), pi=%#x, pl=%d, pi=%d\n", __func__,
 166                  p.pi, p.pl, p.pv.i);
 167         switch (p.pl) {
 168         case 1:
 169                 n += irda_param_pack(buf, "bbb", p.pi, p.pl, (__u8) p.pv.i);
 170                 break;
 171         case 2:
 172                 if (type & PV_BIG_ENDIAN)
 173                         p.pv.i = cpu_to_be16((__u16) p.pv.i);
 174                 else
 175                         p.pv.i = cpu_to_le16((__u16) p.pv.i);
 176                 n += irda_param_pack(buf, "bbs", p.pi, p.pl, (__u16) p.pv.i);
 177                 break;
 178         case 4:
 179                 if (type & PV_BIG_ENDIAN)
 180                         cpu_to_be32s(&p.pv.i);
 181                 else
 182                         cpu_to_le32s(&p.pv.i);
 183                 n += irda_param_pack(buf, "bbi", p.pi, p.pl, p.pv.i);
 184
 185                 break;
 186         default:
 187                 net_warn_ratelimited("%s: length %d not supported\n",
 188                                      __func__, p.pl);
 189                 /* Skip parameter */
 190                 return -1;
 191         }
 192
 193         return p.pl+2; /* Inserted pl+2 bytes */
 194 }
 195
 196 /*
 197  * Function irda_extract integer (self, buf, len, pi, type, func)
 198  *
 199  *    Extract a possibly variable length integer from buffer, and call
 200  *    handler for processing of the parameter
 201  */
 202 static int irda_extract_integer(void *self, __u8 *buf, int len, __u8 pi,
 203                                 PV_TYPE type, PI_HANDLER func)
 204 {
 205         irda_param_t p;
 206         int n = 0;
 207         int extract_len;        /* Real length we extract */
 208         int err;
 209
 210         p.pi = pi;     /* In case handler needs to know */
 211         p.pl = buf[1]; /* Extract length of value */
 212         p.pv.i = 0;    /* Clear value */
 213         extract_len = p.pl;     /* Default : extract all */
 214
 215         /* Check if buffer is long enough for parsing */
 216         if (len < (2+p.pl)) {
 217                 net_warn_ratelimited("%s: buffer too short for parsing! Need %d bytes, but len is only %d\n",
 218                                      __func__, p.pl, len);
 219                 return -1;
 220         }
 221
 222         /*
 223          * Check that the integer length is what we expect it to be. If the
 224          * handler want a 16 bits integer then a 32 bits is not good enough
 225          * PV_INTEGER means that the handler is flexible.
 226          */
 227         if (((type & PV_MASK) != PV_INTEGER) && ((type & PV_MASK) != p.pl)) {
 228                 net_err_ratelimited("%s: invalid parameter length! Expected %d bytes, but value had %d bytes!\n",
 229                                     __func__, type & PV_MASK, p.pl);
 230
 231                 /* Most parameters are bit/byte fields or little endian,
 232                  * so it's ok to only extract a subset of it (the subset
 233                  * that the handler expect). This is necessary, as some
 234                  * broken implementations seems to add extra undefined bits.
 235                  * If the parameter is shorter than we expect or is big
 236                  * endian, we can't play those tricks. Jean II */
 237                 if((p.pl < (type & PV_MASK)) || (type & PV_BIG_ENDIAN)) {
 238                         /* Skip parameter */
 239                         return p.pl+2;
 240                 } else {
 241                         /* Extract subset of it, fallthrough */
 242                         extract_len = type & PV_MASK;
 243                 }
 244         }
 245
 246
 247         switch (extract_len) {
 248         case 1:
 249                 n += irda_param_unpack(buf+2, "b", &p.pv.i);
 250                 break;
 251         case 2:
 252                 n += irda_param_unpack(buf+2, "s", &p.pv.i);
 253                 if (type & PV_BIG_ENDIAN)
 254                         p.pv.i = be16_to_cpu((__u16) p.pv.i);
 255                 else
 256                         p.pv.i = le16_to_cpu((__u16) p.pv.i);
 257                 break;
 258         case 4:
 259                 n += irda_param_unpack(buf+2, "i", &p.pv.i);
 260                 if (type & PV_BIG_ENDIAN)
 261                         be32_to_cpus(&p.pv.i);
 262                 else
 263                         le32_to_cpus(&p.pv.i);
 264                 break;
 265         default:
 266                 net_warn_ratelimited("%s: length %d not supported\n",
 267                                      __func__, p.pl);
 268
 269                 /* Skip parameter */
 270                 return p.pl+2;
 271         }
 272
 273         pr_debug("%s(), pi=%#x, pl=%d, pi=%d\n", __func__,
 274                  p.pi, p.pl, p.pv.i);
 275         /* Call handler for this parameter */
 276         err = (*func)(self, &p, PV_PUT);
 277         if (err < 0)
 278                 return err;
 279
 280         return p.pl+2; /* Extracted pl+2 bytes */
 281 }
 282
 283 /*
 284  * Function irda_extract_string (self, buf, len, type, func)
 285  */
 286 static int irda_extract_string(void *self, __u8 *buf, int len, __u8 pi,
 287                                PV_TYPE type, PI_HANDLER func)
 288 {
 289         char str[33];
 290         irda_param_t p;
 291         int err;
 292
 293         p.pi = pi;     /* In case handler needs to know */
 294         p.pl = buf[1]; /* Extract length of value */
 295         if (p.pl > 32)
 296                 p.pl = 32;
 297
 298         pr_debug("%s(), pi=%#x, pl=%d\n", __func__,
 299                  p.pi, p.pl);
 300
 301         /* Check if buffer is long enough for parsing */
 302         if (len < (2+p.pl)) {
 303                 net_warn_ratelimited("%s: buffer too short for parsing! Need %d bytes, but len is only %d\n",
 304                                      __func__, p.pl, len);
 305                 return -1;
 306         }
 307
 308         /* Should be safe to copy string like this since we have already
 309          * checked that the buffer is long enough */
 310         strncpy(str, buf+2, p.pl);
 311
 312         pr_debug("%s(), str=0x%02x 0x%02x\n",
 313                  __func__, (__u8)str[0], (__u8)str[1]);
 314
 315         /* Null terminate string */
 316         str[p.pl] = '\0';
 317
 318         p.pv.c = str; /* Handler will need to take a copy */
 319
 320         /* Call handler for this parameter */
 321         err = (*func)(self, &p, PV_PUT);
 322         if (err < 0)
 323                 return err;
 324
 325         return p.pl+2; /* Extracted pl+2 bytes */
 326 }
 327
 328 /*
 329  * Function irda_extract_octseq (self, buf, len, type, func)
 330  */
 331 static int irda_extract_octseq(void *self, __u8 *buf, int len, __u8 pi,
 332                                PV_TYPE type, PI_HANDLER func)
 333 {
 334         irda_param_t p;
 335
 336         p.pi = pi;     /* In case handler needs to know */
 337         p.pl = buf[1]; /* Extract length of value */
 338
 339         /* Check if buffer is long enough for parsing */
 340         if (len < (2+p.pl)) {
 341                 net_warn_ratelimited("%s: buffer too short for parsing! Need %d bytes, but len is only %d\n",
 342                                      __func__, p.pl, len);
 343                 return -1;
 344         }
 345
 346         pr_debug("%s(), not impl\n", __func__);
 347
 348         return p.pl+2; /* Extracted pl+2 bytes */
 349 }
 350
 351 /*
 352  * Function irda_param_pack (skb, fmt, ...)
 353  *
 354  *    Format:
 355  *        'i' = 32 bits integer
 356  *        's' = string
 357  *
 358  */
 359 int irda_param_pack(__u8 *buf, char *fmt, ...)
 360 {
 361         irda_pv_t arg;
 362         va_list args;
 363         char *p;
 364         int n = 0;
 365
 366         va_start(args, fmt);
 367
 368         for (p = fmt; *p != '\0'; p++) {
 369                 switch (*p) {
 370                 case 'b':  /* 8 bits unsigned byte */
 371                         buf[n++] = (__u8)va_arg(args, int);
 372                         break;
 373                 case 's':  /* 16 bits unsigned short */
 374                         arg.i = (__u16)va_arg(args, int);
 375                         put_unaligned((__u16)arg.i, (__u16 *)(buf+n)); n+=2;
 376                         break;
 377                 case 'i':  /* 32 bits unsigned integer */
 378                         arg.i = va_arg(args, __u32);
 379                         put_unaligned(arg.i, (__u32 *)(buf+n)); n+=4;
 380                         break;
 381 #if 0
 382                 case 'c': /* \0 terminated string */
 383                         arg.c = va_arg(args, char *);
 384                         strcpy(buf+n, arg.c);
 385                         n += strlen(arg.c) + 1;
 386                         break;
 387 #endif
 388                 default:
 389                         va_end(args);
 390                         return -1;
 391                 }
 392         }
 393         va_end(args);
 394
 395         return 0;
 396 }
 397 EXPORT_SYMBOL(irda_param_pack);
 398
 399 /*
 400  * Function irda_param_unpack (skb, fmt, ...)
 401  */
 402 static int irda_param_unpack(__u8 *buf, char *fmt, ...)
 403 {
 404         irda_pv_t arg;
 405         va_list args;
 406         char *p;
 407         int n = 0;
 408
 409         va_start(args, fmt);
 410
 411         for (p = fmt; *p != '\0'; p++) {
 412                 switch (*p) {
 413                 case 'b':  /* 8 bits byte */
 414                         arg.ip = va_arg(args, __u32 *);
 415                         *arg.ip = buf[n++];
 416                         break;
 417                 case 's':  /* 16 bits short */
 418                         arg.ip = va_arg(args, __u32 *);
 419                         *arg.ip = get_unaligned((__u16 *)(buf+n)); n+=2;
 420                         break;
 421                 case 'i':  /* 32 bits unsigned integer */
 422                         arg.ip = va_arg(args, __u32 *);
 423                         *arg.ip = get_unaligned((__u32 *)(buf+n)); n+=4;
 424                         break;
 425 #if 0
 426                 case 'c':   /* \0 terminated string */
 427                         arg.c = va_arg(args, char *);
 428                         strcpy(arg.c, buf+n);
 429                         n += strlen(arg.c) + 1;
 430                         break;
 431 #endif
 432                 default:
 433                         va_end(args);
 434                         return -1;
 435                 }
 436
 437         }
 438         va_end(args);
 439
 440         return 0;
 441 }
 442
 443 /*
 444  * Function irda_param_insert (self, pi, buf, len, info)
 445  *
 446  *    Insert the specified parameter (pi) into buffer. Returns number of
 447  *    bytes inserted
 448  */
 449 int irda_param_insert(void *self, __u8 pi, __u8 *buf, int len,
 450                       pi_param_info_t *info)
 451 {
 452         const pi_minor_info_t *pi_minor_info;
 453         __u8 pi_minor;
 454         __u8 pi_major;
 455         int type;
 456         int ret = -1;
 457         int n = 0;
 458
 459         IRDA_ASSERT(buf != NULL, return ret;);
 460         IRDA_ASSERT(info != NULL, return ret;);
 461
 462         pi_minor = pi & info->pi_mask;
 463         pi_major = pi >> info->pi_major_offset;
 464
 465         /* Check if the identifier value (pi) is valid */
 466         if ((pi_major > info->len-1) ||
 467             (pi_minor > info->tables[pi_major].len-1))
 468         {
 469                 pr_debug("%s(), no handler for parameter=0x%02x\n",
 470                          __func__, pi);
 471
 472                 /* Skip this parameter */
 473                 return -1;
 474         }
 475
 476         /* Lookup the info on how to parse this parameter */
 477         pi_minor_info = &info->tables[pi_major].pi_minor_call_table[pi_minor];
 478
 479         /* Find expected data type for this parameter identifier (pi)*/
 480         type = pi_minor_info->type;
 481
 482         /*  Check if handler has been implemented */
 483         if (!pi_minor_info->func) {
 484                 net_info_ratelimited("%s: no handler for pi=%#x\n",
 485                                      __func__, pi);
 486                 /* Skip this parameter */
 487                 return -1;
 488         }
 489
 490         /* Insert parameter value */
 491         ret = (*pv_insert_table[type & PV_MASK])(self, buf+n, len, pi, type,
 492                                                  pi_minor_info->func);
 493         return ret;
 494 }
 495 EXPORT_SYMBOL(irda_param_insert);
 496
 497 /*
 498  * Function irda_param_extract (self, buf, len, info)
 499  *
 500  *    Parse all parameters. If len is correct, then everything should be
 501  *    safe. Returns the number of bytes that was parsed
 502  *
 503  */
 504 static int irda_param_extract(void *self, __u8 *buf, int len,
 505                               pi_param_info_t *info)
 506 {
 507         const pi_minor_info_t *pi_minor_info;
 508         __u8 pi_minor;
 509         __u8 pi_major;
 510         int type;
 511         int ret = -1;
 512         int n = 0;
 513
 514         IRDA_ASSERT(buf != NULL, return ret;);
 515         IRDA_ASSERT(info != NULL, return ret;);
 516
 517         pi_minor = buf[n] & info->pi_mask;
 518         pi_major = buf[n] >> info->pi_major_offset;
 519
 520         /* Check if the identifier value (pi) is valid */
 521         if ((pi_major > info->len-1) ||
 522             (pi_minor > info->tables[pi_major].len-1))
 523         {
 524                 pr_debug("%s(), no handler for parameter=0x%02x\n",
 525                          __func__, buf[0]);
 526
 527                 /* Skip this parameter */
 528                 return 2 + buf[n + 1];  /* Continue */
 529         }
 530
 531         /* Lookup the info on how to parse this parameter */
 532         pi_minor_info = &info->tables[pi_major].pi_minor_call_table[pi_minor];
 533
 534         /* Find expected data type for this parameter identifier (pi)*/
 535         type = pi_minor_info->type;
 536
 537         pr_debug("%s(), pi=[%d,%d], type=%d\n", __func__,
 538                  pi_major, pi_minor, type);
 539
 540         /*  Check if handler has been implemented */
 541         if (!pi_minor_info->func) {
 542                 net_info_ratelimited("%s: no handler for pi=%#x\n",
 543                                      __func__, buf[n]);
 544                 /* Skip this parameter */
 545                 return 2 + buf[n + 1]; /* Continue */
 546         }
 547
 548         /* Parse parameter value */
 549         ret = (*pv_extract_table[type & PV_MASK])(self, buf+n, len, buf[n],
 550                                                   type, pi_minor_info->func);
 551         return ret;
 552 }
 553
 554 /*
 555  * Function irda_param_extract_all (self, buf, len, info)
 556  *
 557  *    Parse all parameters. If len is correct, then everything should be
 558  *    safe. Returns the number of bytes that was parsed
 559  *
 560  */
 561 int irda_param_extract_all(void *self, __u8 *buf, int len,
 562                            pi_param_info_t *info)
 563 {
 564         int ret = -1;
 565         int n = 0;
 566
 567         IRDA_ASSERT(buf != NULL, return ret;);
 568         IRDA_ASSERT(info != NULL, return ret;);
 569
 570         /*
 571          * Parse all parameters. Each parameter must be at least two bytes
 572          * long or else there is no point in trying to parse it
 573          */
 574         while (len > 2) {
 575                 ret = irda_param_extract(self, buf+n, len, info);
 576                 if (ret < 0)
 577                         return ret;
 578
 579                 n += ret;
 580                 len -= ret;
 581         }
 582         return n;
 583 }
 584 EXPORT_SYMBOL(irda_param_extract_all);