LXR linux/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, write to the Free Software
  26 *     Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  27 *     MA 02111-1307 USA
  28 *
  29 ********************************************************************/
  30
  31#include <linux/types.h>
  32#include <linux/module.h>
  33
  34#include <asm/unaligned.h>
  35#include <asm/byteorder.h>
  36
  37#include <net/irda/irda.h>
  38#include <net/irda/parameters.h>
  39
  40static int irda_extract_integer(void *self, __u8 *buf, int len, __u8 pi,
  41                                PV_TYPE type, PI_HANDLER func);
  42static int irda_extract_string(void *self, __u8 *buf, int len, __u8 pi,
  43                               PV_TYPE type, PI_HANDLER func);
  44static int irda_extract_octseq(void *self, __u8 *buf, int len, __u8 pi,
  45                               PV_TYPE type, PI_HANDLER func);
  46static int irda_extract_no_value(void *self, __u8 *buf, int len, __u8 pi,
  47                                 PV_TYPE type, PI_HANDLER func);
  48
  49static int irda_insert_integer(void *self, __u8 *buf, int len, __u8 pi,
  50                               PV_TYPE type, PI_HANDLER func);
  51static int irda_insert_no_value(void *self, __u8 *buf, int len, __u8 pi,
  52                                PV_TYPE type, PI_HANDLER func);
  53
  54static int irda_param_unpack(__u8 *buf, char *fmt, ...);
  55
  56/* Parameter value call table. Must match PV_TYPE */
  57static PV_HANDLER pv_extract_table[] = {
  58        irda_extract_integer, /* Handler for any length integers */
  59        irda_extract_integer, /* Handler for 8  bits integers */
  60        irda_extract_integer, /* Handler for 16 bits integers */
  61        irda_extract_string,  /* Handler for strings */
  62        irda_extract_integer, /* Handler for 32 bits integers */
  63        irda_extract_octseq,  /* Handler for octet sequences */
  64        irda_extract_no_value /* Handler for no value parameters */
  65};
  66
  67static PV_HANDLER pv_insert_table[] = {
  68        irda_insert_integer, /* Handler for any length integers */
  69        irda_insert_integer, /* Handler for 8  bits integers */
  70        irda_insert_integer, /* Handler for 16 bits integers */
  71        NULL,                /* Handler for strings */
  72        irda_insert_integer, /* Handler for 32 bits integers */
  73        NULL,                /* Handler for octet sequences */
  74        irda_insert_no_value /* Handler for no value parameters */
  75};
  76
  77/*
  78 * Function irda_insert_no_value (self, buf, len, pi, type, func)
  79 */
  80static int irda_insert_no_value(void *self, __u8 *buf, int len, __u8 pi,
  81                                PV_TYPE type, PI_HANDLER func)
  82{
  83        irda_param_t p;
  84        int ret;
  85
  86        p.pi = pi;
  87        p.pl = 0;
  88
  89        /* Call handler for this parameter */
  90        ret = (*func)(self, &p, PV_GET);
  91
  92        /* Extract values anyway, since handler may need them */
  93        irda_param_pack(buf, "bb", p.pi, p.pl);
  94
  95        if (ret < 0)
  96                return ret;
  97
  98        return 2; /* Inserted pl+2 bytes */
  99}
 100
 101/*
 102 * Function irda_extract_no_value (self, buf, len, type, func)
 103 *
 104 *    Extracts a parameter without a pv field (pl=0)
 105 *
 106 */
 107static int irda_extract_no_value(void *self, __u8 *buf, int len, __u8 pi,
 108                                 PV_TYPE type, PI_HANDLER func)
 109{
 110        irda_param_t p;
 111        int ret;
 112
 113        /* Extract values anyway, since handler may need them */
 114        irda_param_unpack(buf, "bb", &p.pi, &p.pl);
 115
 116        /* Call handler for this parameter */
 117        ret = (*func)(self, &p, PV_PUT);
 118
 119        if (ret < 0)
 120                return ret;
 121
 122        return 2; /* Extracted pl+2 bytes */
 123}
 124
 125/*
 126 * Function irda_insert_integer (self, buf, len, pi, type, func)
 127 */
 128static int irda_insert_integer(void *self, __u8 *buf, int len, __u8 pi,
 129                               PV_TYPE type, PI_HANDLER func)
 130{
 131        irda_param_t p;
 132        int n = 0;
 133        int err;
 134
 135        p.pi = pi;             /* In case handler needs to know */
 136        p.pl = type & PV_MASK; /* The integer type codes the length as well */
 137        p.pv.i = 0;            /* Clear value */
 138
 139        /* Call handler for this parameter */
 140        err = (*func)(self, &p, PV_GET);
 141        if (err < 0)
 142                return err;
 143
 144        /*
 145         * If parameter length is still 0, then (1) this is an any length
 146         * integer, and (2) the handler function does not care which length
 147         * we choose to use, so we pick the one the gives the fewest bytes.
 148         */
 149        if (p.pl == 0) {
 150                if (p.pv.i < 0xff) {
 151                        IRDA_DEBUG(2, "%s(), using 1 byte\n", __func__);
 152                        p.pl = 1;
 153                } else if (p.pv.i < 0xffff) {
 154                        IRDA_DEBUG(2, "%s(), using 2 bytes\n", __func__);
 155                        p.pl = 2;
 156                } else {
 157                        IRDA_DEBUG(2, "%s(), using 4 bytes\n", __func__);
 158                        p.pl = 4; /* Default length */
 159                }
 160        }
 161        /* Check if buffer is long enough for insertion */
 162        if (len < (2+p.pl)) {
 163                IRDA_WARNING("%s: buffer too short for insertion!\n",
 164                             __func__);
 165                return -1;
 166        }
 167        IRDA_DEBUG(2, "%s(), pi=%#x, pl=%d, pi=%d\n", __func__,
 168                   p.pi, p.pl, p.pv.i);
 169        switch (p.pl) {
 170        case 1:
 171                n += irda_param_pack(buf, "bbb", p.pi, p.pl, (__u8) p.pv.i);
 172                break;
 173        case 2:
 174                if (type & PV_BIG_ENDIAN)
 175                        p.pv.i = cpu_to_be16((__u16) p.pv.i);
 176                else
 177                        p.pv.i = cpu_to_le16((__u16) p.pv.i);
 178                n += irda_param_pack(buf, "bbs", p.pi, p.pl, (__u16) p.pv.i);
 179                break;
 180        case 4:
 181                if (type & PV_BIG_ENDIAN)
 182                        cpu_to_be32s(&p.pv.i);
 183                else
 184                        cpu_to_le32s(&p.pv.i);
 185                n += irda_param_pack(buf, "bbi", p.pi, p.pl, p.pv.i);
 186
 187                break;
 188        default:
 189                IRDA_WARNING("%s: length %d not supported\n",
 190                             __func__, p.pl);
 191                /* Skip parameter */
 192                return -1;
 193        }
 194
 195        return p.pl+2; /* Inserted pl+2 bytes */
 196}
 197
 198/*
 199 * Function irda_extract integer (self, buf, len, pi, type, func)
 200 *
 201 *    Extract a possibly variable length integer from buffer, and call
 202 *    handler for processing of the parameter
 203 */
 204static int irda_extract_integer(void *self, __u8 *buf, int len, __u8 pi,
 205                                PV_TYPE type, PI_HANDLER func)
 206{
 207        irda_param_t p;
 208        int n = 0;
 209        int extract_len;        /* Real length we extract */
 210        int err;
 211
 212        p.pi = pi;     /* In case handler needs to know */
 213        p.pl = buf[1]; /* Extract length of value */
 214        p.pv.i = 0;    /* Clear value */
 215        extract_len = p.pl;     /* Default : extract all */
 216
 217        /* Check if buffer is long enough for parsing */
 218        if (len < (2+p.pl)) {
 219                IRDA_WARNING("%s: buffer too short for parsing! "
 220                             "Need %d bytes, but len is only %d\n",
 221                             __func__, p.pl, len);
 222                return -1;
 223        }
 224
 225        /*
 226         * Check that the integer length is what we expect it to be. If the
 227         * handler want a 16 bits integer then a 32 bits is not good enough
 228         * PV_INTEGER means that the handler is flexible.
 229         */
 230        if (((type & PV_MASK) != PV_INTEGER) && ((type & PV_MASK) != p.pl)) {
 231                IRDA_ERROR("%s: invalid parameter length! "
 232                           "Expected %d bytes, but value had %d bytes!\n",
 233                           __func__, type & PV_MASK, p.pl);
 234
 235                /* Most parameters are bit/byte fields or little endian,
 236                 * so it's ok to only extract a subset of it (the subset
 237                 * that the handler expect). This is necessary, as some
 238                 * broken implementations seems to add extra undefined bits.
 239                 * If the parameter is shorter than we expect or is big
 240                 * endian, we can't play those tricks. Jean II */
 241                if((p.pl < (type & PV_MASK)) || (type & PV_BIG_ENDIAN)) {
 242                        /* Skip parameter */
 243                        return p.pl+2;
 244                } else {
 245                        /* Extract subset of it, fallthrough */
 246                        extract_len = type & PV_MASK;
 247                }
 248        }
 249
 250
 251        switch (extract_len) {
 252        case 1:
 253                n += irda_param_unpack(buf+2, "b", &p.pv.i);
 254                break;
 255        case 2:
 256                n += irda_param_unpack(buf+2, "s", &p.pv.i);
 257                if (type & PV_BIG_ENDIAN)
 258                        p.pv.i = be16_to_cpu((__u16) p.pv.i);
 259                else
 260                        p.pv.i = le16_to_cpu((__u16) p.pv.i);
 261                break;
 262        case 4:
 263                n += irda_param_unpack(buf+2, "i", &p.pv.i);
 264                if (type & PV_BIG_ENDIAN)
 265                        be32_to_cpus(&p.pv.i);
 266                else
 267                        le32_to_cpus(&p.pv.i);
 268                break;
 269        default:
 270                IRDA_WARNING("%s: length %d not supported\n",
 271                             __func__, p.pl);
 272
 273                /* Skip parameter */
 274                return p.pl+2;
 275        }
 276
 277        IRDA_DEBUG(2, "%s(), pi=%#x, pl=%d, pi=%d\n", __func__,
 278                   p.pi, p.pl, p.pv.i);
 279        /* Call handler for this parameter */
 280        err = (*func)(self, &p, PV_PUT);
 281        if (err < 0)
 282                return err;
 283
 284        return p.pl+2; /* Extracted pl+2 bytes */
 285}
 286
 287/*
 288 * Function irda_extract_string (self, buf, len, type, func)
 289 */
 290static int irda_extract_string(void *self, __u8 *buf, int len, __u8 pi,
 291                               PV_TYPE type, PI_HANDLER func)
 292{
 293        char str[33];
 294        irda_param_t p;
 295        int err;
 296
 297        IRDA_DEBUG(2, "%s()\n", __func__);
 298
 299        p.pi = pi;     /* In case handler needs to know */
 300        p.pl = buf[1]; /* Extract length of value */
 301
 302        IRDA_DEBUG(2, "%s(), pi=%#x, pl=%d\n", __func__,
 303                   p.pi, p.pl);
 304
 305        /* Check if buffer is long enough for parsing */
 306        if (len < (2+p.pl)) {
 307                IRDA_WARNING("%s: buffer too short for parsing! "
 308                             "Need %d bytes, but len is only %d\n",
 309                             __func__, p.pl, len);
 310                return -1;
 311        }
 312
 313        /* Should be safe to copy string like this since we have already
 314         * checked that the buffer is long enough */
 315        strncpy(str, buf+2, p.pl);
 316
 317        IRDA_DEBUG(2, "%s(), str=0x%02x 0x%02x\n", __func__,
 318                   (__u8) str[0], (__u8) str[1]);
 319
 320        /* Null terminate string */
 321        str[p.pl+1] = '\0';
 322
 323        p.pv.c = str; /* Handler will need to take a copy */
 324
 325        /* Call handler for this parameter */
 326        err = (*func)(self, &p, PV_PUT);
 327        if (err < 0)
 328                return err;
 329
 330        return p.pl+2; /* Extracted pl+2 bytes */
 331}
 332
 333/*
 334 * Function irda_extract_octseq (self, buf, len, type, func)
 335 */
 336static int irda_extract_octseq(void *self, __u8 *buf, int len, __u8 pi,
 337                               PV_TYPE type, PI_HANDLER func)
 338{
 339        irda_param_t p;
 340
 341        p.pi = pi;     /* In case handler needs to know */
 342        p.pl = buf[1]; /* Extract length of value */
 343
 344        /* Check if buffer is long enough for parsing */
 345        if (len < (2+p.pl)) {
 346                IRDA_WARNING("%s: buffer too short for parsing! "
 347                             "Need %d bytes, but len is only %d\n",
 348                             __func__, p.pl, len);
 349                return -1;
 350        }
 351
 352        IRDA_DEBUG(0, "%s(), not impl\n", __func__);
 353
 354        return p.pl+2; /* Extracted pl+2 bytes */
 355}
 356
 357/*
 358 * Function irda_param_pack (skb, fmt, ...)
 359 *
 360 *    Format:
 361 *        'i' = 32 bits integer
 362 *        's' = string
 363 *
 364 */
 365int irda_param_pack(__u8 *buf, char *fmt, ...)
 366{
 367        irda_pv_t arg;
 368        va_list args;
 369        char *p;
 370        int n = 0;
 371
 372        va_start(args, fmt);
 373
 374        for (p = fmt; *p != '\0'; p++) {
 375                switch (*p) {
 376                case 'b':  /* 8 bits unsigned byte */
 377                        buf[n++] = (__u8)va_arg(args, int);
 378                        break;
 379                case 's':  /* 16 bits unsigned short */
 380                        arg.i = (__u16)va_arg(args, int);
 381                        put_unaligned((__u16)arg.i, (__u16 *)(buf+n)); n+=2;
 382                        break;
 383                case 'i':  /* 32 bits unsigned integer */
 384                        arg.i = va_arg(args, __u32);
 385                        put_unaligned(arg.i, (__u32 *)(buf+n)); n+=4;
 386                        break;
 387#if 0
 388                case 'c': /* \0 terminated string */
 389                        arg.c = va_arg(args, char *);
 390                        strcpy(buf+n, arg.c);
 391                        n += strlen(arg.c) + 1;
 392                        break;
 393#endif
 394                default:
 395                        va_end(args);
 396                        return -1;
 397                }
 398        }
 399        va_end(args);
 400
 401        return 0;
 402}
 403EXPORT_SYMBOL(irda_param_pack);
 404
 405/*
 406 * Function irda_param_unpack (skb, fmt, ...)
 407 */
 408static int irda_param_unpack(__u8 *buf, char *fmt, ...)
 409{
 410        irda_pv_t arg;
 411        va_list args;
 412        char *p;
 413        int n = 0;
 414
 415        va_start(args, fmt);
 416
 417        for (p = fmt; *p != '\0'; p++) {
 418                switch (*p) {
 419                case 'b':  /* 8 bits byte */
 420                        arg.ip = va_arg(args, __u32 *);
 421                        *arg.ip = buf[n++];
 422                        break;
 423                case 's':  /* 16 bits short */
 424                        arg.ip = va_arg(args, __u32 *);
 425                        *arg.ip = get_unaligned((__u16 *)(buf+n)); n+=2;
 426                        break;
 427                case 'i':  /* 32 bits unsigned integer */
 428                        arg.ip = va_arg(args, __u32 *);
 429                        *arg.ip = get_unaligned((__u32 *)(buf+n)); n+=4;
 430                        break;
 431#if 0
 432                case 'c':   /* \0 terminated string */
 433                        arg.c = va_arg(args, char *);
 434                        strcpy(arg.c, buf+n);
 435                        n += strlen(arg.c) + 1;
 436                        break;
 437#endif
 438                default:
 439                        va_end(args);
 440                        return -1;
 441                }
 442
 443        }
 444        va_end(args);
 445
 446        return 0;
 447}
 448
 449/*
 450 * Function irda_param_insert (self, pi, buf, len, info)
 451 *
 452 *    Insert the specified parameter (pi) into buffer. Returns number of
 453 *    bytes inserted
 454 */
 455int irda_param_insert(void *self, __u8 pi, __u8 *buf, int len,
 456                      pi_param_info_t *info)
 457{
 458        pi_minor_info_t *pi_minor_info;
 459        __u8 pi_minor;
 460        __u8 pi_major;
 461        int type;
 462        int ret = -1;
 463        int n = 0;
 464
 465        IRDA_ASSERT(buf != NULL, return ret;);
 466        IRDA_ASSERT(info != NULL, return ret;);
 467
 468        pi_minor = pi & info->pi_mask;
 469        pi_major = pi >> info->pi_major_offset;
 470
 471        /* Check if the identifier value (pi) is valid */
 472        if ((pi_major > info->len-1) ||
 473            (pi_minor > info->tables[pi_major].len-1))
 474        {
 475                IRDA_DEBUG(0, "%s(), no handler for parameter=0x%02x\n",
 476                           __func__, pi);
 477
 478                /* Skip this parameter */
 479                return -1;
 480        }
 481
 482        /* Lookup the info on how to parse this parameter */
 483        pi_minor_info = &info->tables[pi_major].pi_minor_call_table[pi_minor];
 484
 485        /* Find expected data type for this parameter identifier (pi)*/
 486        type = pi_minor_info->type;
 487
 488        /*  Check if handler has been implemented */
 489        if (!pi_minor_info->func) {
 490                IRDA_MESSAGE("%s: no handler for pi=%#x\n", __func__, pi);
 491                /* Skip this parameter */
 492                return -1;
 493        }
 494
 495        /* Insert parameter value */
 496        ret = (*pv_insert_table[type & PV_MASK])(self, buf+n, len, pi, type,
 497                                                 pi_minor_info->func);
 498        return ret;
 499}
 500EXPORT_SYMBOL(irda_param_insert);
 501
 502/*
 503 * Function irda_param_extract (self, buf, len, info)
 504 *
 505 *    Parse all parameters. If len is correct, then everything should be
 506 *    safe. Returns the number of bytes that was parsed
 507 *
 508 */
 509static int irda_param_extract(void *self, __u8 *buf, int len,
 510                              pi_param_info_t *info)
 511{
 512        pi_minor_info_t *pi_minor_info;
 513        __u8 pi_minor;
 514        __u8 pi_major;
 515        int type;
 516        int ret = -1;
 517        int n = 0;
 518
 519        IRDA_ASSERT(buf != NULL, return ret;);
 520        IRDA_ASSERT(info != NULL, return ret;);
 521
 522        pi_minor = buf[n] & info->pi_mask;
 523        pi_major = buf[n] >> info->pi_major_offset;
 524
 525        /* Check if the identifier value (pi) is valid */
 526        if ((pi_major > info->len-1) ||
 527            (pi_minor > info->tables[pi_major].len-1))
 528        {
 529                IRDA_DEBUG(0, "%s(), no handler for parameter=0x%02x\n",
 530                           __func__, buf[0]);
 531
 532                /* Skip this parameter */
 533                return 2 + buf[n + 1];  /* Continue */
 534        }
 535
 536        /* Lookup the info on how to parse this parameter */
 537        pi_minor_info = &info->tables[pi_major].pi_minor_call_table[pi_minor];
 538
 539        /* Find expected data type for this parameter identifier (pi)*/
 540        type = pi_minor_info->type;
 541
 542        IRDA_DEBUG(3, "%s(), pi=[%d,%d], type=%d\n", __func__,
 543                   pi_major, pi_minor, type);
 544
 545        /*  Check if handler has been implemented */
 546        if (!pi_minor_info->func) {
 547                IRDA_MESSAGE("%s: no handler for pi=%#x\n",
 548                             __func__, buf[n]);
 549                /* Skip this parameter */
 550                return 2 + buf[n + 1]; /* Continue */
 551        }
 552
 553        /* Parse parameter value */
 554        ret = (*pv_extract_table[type & PV_MASK])(self, buf+n, len, buf[n],
 555                                                  type, pi_minor_info->func);
 556        return ret;
 557}
 558
 559/*
 560 * Function irda_param_extract_all (self, buf, len, info)
 561 *
 562 *    Parse all parameters. If len is correct, then everything should be
 563 *    safe. Returns the number of bytes that was parsed
 564 *
 565 */
 566int irda_param_extract_all(void *self, __u8 *buf, int len,
 567                           pi_param_info_t *info)
 568{
 569        int ret = -1;
 570        int n = 0;
 571
 572        IRDA_ASSERT(buf != NULL, return ret;);
 573        IRDA_ASSERT(info != NULL, return ret;);
 574
 575        /*
 576         * Parse all parameters. Each parameter must be at least two bytes
 577         * long or else there is no point in trying to parse it
 578         */
 579        while (len > 2) {
 580                ret = irda_param_extract(self, buf+n, len, info);
 581                if (ret < 0)
 582                        return ret;
 583
 584                n += ret;
 585                len -= ret;
 586        }
 587        return n;
 588}
 589EXPORT_SYMBOL(irda_param_extract_all);
 590