src/p2p/p2p_utils.c

   1 /*
   2  * P2P - generic helper functions
   3  * Copyright (c) 2009, Atheros Communications
   4  *
   5  * This software may be distributed under the terms of the BSD license.
   6  * See README for more details.
   7  */
   8
   9 #include "includes.h"
  10
  11 #include "common.h"
  12 #include "p2p_i.h"
  13
  14
  15 /**
  16  * p2p_random - Generate random string for SSID and passphrase
  17  * @buf: Buffer for returning the result
  18  * @len: Number of octets to write to the buffer
  19  * Returns: 0 on success, -1 on failure
  20  *
  21  * This function generates a random string using the following character set:
  22  * 'A'-'Z', 'a'-'z', '0'-'9'.
  23  */
  24 int p2p_random(char *buf, size_t len)
  25 {
  26         u8 val;
  27         size_t i;
  28         u8 letters = 'Z' - 'A' + 1;
  29         u8 numbers = 10;
  30
  31         if (os_get_random((unsigned char *) buf, len))
  32                 return -1;
  33         /* Character set: 'A'-'Z', 'a'-'z', '0'-'9' */
  34         for (i = 0; i < len; i++) {
  35                 val = buf[i];
  36                 val %= 2 * letters + numbers;
  37                 if (val < letters)
  38                         buf[i] = 'A' + val;
  39                 else if (val < 2 * letters)
  40                         buf[i] = 'a' + (val - letters);
  41                 else
  42                         buf[i] = '0' + (val - 2 * letters);
  43         }
  44
  45         return 0;
  46 }
  47
  48
  49 /**
  50  * p2p_channel_to_freq - Convert channel info to frequency
  51  * @op_class: Operating class
  52  * @channel: Channel number
  53  * Returns: Frequency in MHz or -1 if the specified channel is unknown
  54  */
  55 int p2p_channel_to_freq(int op_class, int channel)
  56 {
  57         /* Table E-4 in IEEE Std 802.11-2012 - Global operating classes */
  58         /* TODO: more operating classes */
  59         switch (op_class) {
  60         case 81:
  61                 /* channels 1..13 */
  62                 if (channel < 1 || channel > 13)
  63                         return -1;
  64                 return 2407 + 5 * channel;
  65         case 82:
  66                 /* channel 14 */
  67                 if (channel != 14)
  68                         return -1;
  69                 return 2414 + 5 * channel;
  70         case 83: /* channels 1..9; 40 MHz */
  71         case 84: /* channels 5..13; 40 MHz */
  72                 if (channel < 1 || channel > 13)
  73                         return -1;
  74                 return 2407 + 5 * channel;
  75         case 115: /* channels 36,40,44,48; indoor only */
  76         case 118: /* channels 52,56,60,64; dfs */
  77                 if (channel < 36 || channel > 64)
  78                         return -1;
  79                 return 5000 + 5 * channel;
  80         case 124: /* channels 149,153,157,161 */
  81         case 125: /* channels 149,153,157,161,165,169 */
  82                 if (channel < 149 || channel > 161)
  83                         return -1;
  84                 return 5000 + 5 * channel;
  85         case 116: /* channels 36,44; 40 MHz; indoor only */
  86         case 117: /* channels 40,48; 40 MHz; indoor only */
  87         case 119: /* channels 52,60; 40 MHz; dfs */
  88         case 120: /* channels 56,64; 40 MHz; dfs */
  89                 if (channel < 36 || channel > 64)
  90                         return -1;
  91                 return 5000 + 5 * channel;
  92         case 126: /* channels 149,157; 40 MHz */
  93         case 127: /* channels 153,161; 40 MHz */
  94                 if (channel < 149 || channel > 161)
  95                         return -1;
  96                 return 5000 + 5 * channel;
  97         case 128: /* center freqs 42, 58, 106, 122, 138, 155; 80 MHz */
  98                 if (channel < 36 || channel > 161)
  99                         return -1;
 100                 return 5000 + 5 * channel;
 101         case 180: /* 60 GHz band, channels 1..4 */
 102                 if (channel < 1 || channel > 4)
 103                         return -1;
 104                 return 56160 + 2160 * channel;
 105         }
 106         return -1;
 107 }
 108
 109
 110 /**
 111  * p2p_freq_to_channel - Convert frequency into channel info
 112  * @op_class: Buffer for returning operating class
 113  * @channel: Buffer for returning channel number
 114  * Returns: 0 on success, -1 if the specified frequency is unknown
 115  */
 116 int p2p_freq_to_channel(unsigned int freq, u8 *op_class, u8 *channel)
 117 {
 118         /* TODO: more operating classes */
 119         if (freq >= 2412 && freq <= 2472) {
 120                 if ((freq - 2407) % 5)
 121                         return -1;
 122
 123                 *op_class = 81; /* 2.407 GHz, channels 1..13 */
 124                 *channel = (freq - 2407) / 5;
 125                 return 0;
 126         }
 127
 128         if (freq == 2484) {
 129                 *op_class = 82; /* channel 14 */
 130                 *channel = 14;
 131                 return 0;
 132         }
 133
 134         if (freq >= 5180 && freq <= 5240) {
 135                 if ((freq - 5000) % 5)
 136                         return -1;
 137
 138                 *op_class = 115; /* 5 GHz, channels 36..48 */
 139                 *channel = (freq - 5000) / 5;
 140                 return 0;
 141         }
 142
 143         if (freq >= 5745 && freq <= 5805) {
 144                 if ((freq - 5000) % 5)
 145                         return -1;
 146
 147                 *op_class = 124; /* 5 GHz, channels 149..161 */
 148                 *channel = (freq - 5000) / 5;
 149                 return 0;
 150         }
 151
 152         return -1;
 153 }
 154
 155
 156 static void p2p_reg_class_intersect(const struct p2p_reg_class *a,
 157                                     const struct p2p_reg_class *b,
 158                                     struct p2p_reg_class *res)
 159 {
 160         size_t i, j;
 161
 162         res->reg_class = a->reg_class;
 163
 164         for (i = 0; i < a->channels; i++) {
 165                 for (j = 0; j < b->channels; j++) {
 166                         if (a->channel[i] != b->channel[j])
 167                                 continue;
 168                         res->channel[res->channels] = a->channel[i];
 169                         res->channels++;
 170                         if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)
 171                                 return;
 172                 }
 173         }
 174 }
 175
 176
 177 /**
 178  * p2p_channels_intersect - Intersection of supported channel lists
 179  * @a: First set of supported channels
 180  * @b: Second set of supported channels
 181  * @res: Data structure for returning the intersection of support channels
 182  *
 183  * This function can be used to find a common set of supported channels. Both
 184  * input channels sets are assumed to use the same country code. If different
 185  * country codes are used, the regulatory class numbers may not be matched
 186  * correctly and results are undefined.
 187  */
 188 void p2p_channels_intersect(const struct p2p_channels *a,
 189                             const struct p2p_channels *b,
 190                             struct p2p_channels *res)
 191 {
 192         size_t i, j;
 193
 194         os_memset(res, 0, sizeof(*res));
 195
 196         for (i = 0; i < a->reg_classes; i++) {
 197                 const struct p2p_reg_class *a_reg = &a->reg_class[i];
 198                 for (j = 0; j < b->reg_classes; j++) {
 199                         const struct p2p_reg_class *b_reg = &b->reg_class[j];
 200                         if (a_reg->reg_class != b_reg->reg_class)
 201                                 continue;
 202                         p2p_reg_class_intersect(
 203                                 a_reg, b_reg,
 204                                 &res->reg_class[res->reg_classes]);
 205                         if (res->reg_class[res->reg_classes].channels) {
 206                                 res->reg_classes++;
 207                                 if (res->reg_classes == P2P_MAX_REG_CLASSES)
 208                                         return;
 209                         }
 210                 }
 211         }
 212 }
 213
 214
 215 static void p2p_op_class_union(struct p2p_reg_class *cl,
 216                                const struct p2p_reg_class *b_cl)
 217 {
 218         size_t i, j;
 219
 220         for (i = 0; i < b_cl->channels; i++) {
 221                 for (j = 0; j < cl->channels; j++) {
 222                         if (b_cl->channel[i] == cl->channel[j])
 223                                 break;
 224                 }
 225                 if (j == cl->channels) {
 226                         if (cl->channels == P2P_MAX_REG_CLASS_CHANNELS)
 227                                 return;
 228                         cl->channel[cl->channels++] = b_cl->channel[i];
 229                 }
 230         }
 231 }
 232
 233
 234 /**
 235  * p2p_channels_union - Union of channel lists
 236  * @a: First set of channels
 237  * @b: Second set of channels
 238  * @res: Data structure for returning the union of channels
 239  */
 240 void p2p_channels_union(const struct p2p_channels *a,
 241                         const struct p2p_channels *b,
 242                         struct p2p_channels *res)
 243 {
 244         size_t i, j;
 245
 246         if (a != res)
 247                 os_memcpy(res, a, sizeof(*res));
 248
 249         for (i = 0; i < res->reg_classes; i++) {
 250                 struct p2p_reg_class *cl = &res->reg_class[i];
 251                 for (j = 0; j < b->reg_classes; j++) {
 252                         const struct p2p_reg_class *b_cl = &b->reg_class[j];
 253                         if (cl->reg_class != b_cl->reg_class)
 254                                 continue;
 255                         p2p_op_class_union(cl, b_cl);
 256                 }
 257         }
 258
 259         for (j = 0; j < b->reg_classes; j++) {
 260                 const struct p2p_reg_class *b_cl = &b->reg_class[j];
 261
 262                 for (i = 0; i < res->reg_classes; i++) {
 263                         struct p2p_reg_class *cl = &res->reg_class[i];
 264                         if (cl->reg_class == b_cl->reg_class)
 265                                 break;
 266                 }
 267
 268                 if (i == res->reg_classes) {
 269                         if (res->reg_classes == P2P_MAX_REG_CLASSES)
 270                                 return;
 271                         os_memcpy(&res->reg_class[res->reg_classes++],
 272                                   b_cl, sizeof(struct p2p_reg_class));
 273                 }
 274         }
 275 }
 276
 277
 278 void p2p_channels_remove_freqs(struct p2p_channels *chan,
 279                                const struct wpa_freq_range_list *list)
 280 {
 281         size_t o, c;
 282
 283         if (list == NULL)
 284                 return;
 285
 286         o = 0;
 287         while (o < chan->reg_classes) {
 288                 struct p2p_reg_class *op = &chan->reg_class[o];
 289
 290                 c = 0;
 291                 while (c < op->channels) {
 292                         int freq = p2p_channel_to_freq(op->reg_class,
 293                                                        op->channel[c]);
 294                         if (freq > 0 && freq_range_list_includes(list, freq)) {
 295                                 op->channels--;
 296                                 os_memmove(&op->channel[c],
 297                                            &op->channel[c + 1],
 298                                            op->channels - c);
 299                         } else
 300                                 c++;
 301                 }
 302
 303                 if (op->channels == 0) {
 304                         chan->reg_classes--;
 305                         os_memmove(&chan->reg_class[o], &chan->reg_class[o + 1],
 306                                    (chan->reg_classes - o) *
 307                                    sizeof(struct p2p_reg_class));
 308                 } else
 309                         o++;
 310         }
 311 }
 312
 313
 314 /**
 315  * p2p_channels_includes - Check whether a channel is included in the list
 316  * @channels: List of supported channels
 317  * @reg_class: Regulatory class of the channel to search
 318  * @channel: Channel number of the channel to search
 319  * Returns: 1 if channel was found or 0 if not
 320  */
 321 int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,
 322                           u8 channel)
 323 {
 324         size_t i, j;
 325         for (i = 0; i < channels->reg_classes; i++) {
 326                 const struct p2p_reg_class *reg = &channels->reg_class[i];
 327                 if (reg->reg_class != reg_class)
 328                         continue;
 329                 for (j = 0; j < reg->channels; j++) {
 330                         if (reg->channel[j] == channel)
 331                                 return 1;
 332                 }
 333         }
 334         return 0;
 335 }
 336
 337
 338 int p2p_channels_includes_freq(const struct p2p_channels *channels,
 339                                unsigned int freq)
 340 {
 341         size_t i, j;
 342         for (i = 0; i < channels->reg_classes; i++) {
 343                 const struct p2p_reg_class *reg = &channels->reg_class[i];
 344                 for (j = 0; j < reg->channels; j++) {
 345                         if (p2p_channel_to_freq(reg->reg_class,
 346                                                 reg->channel[j]) == (int) freq)
 347                                 return 1;
 348                 }
 349         }
 350         return 0;
 351 }
 352
 353
 354 int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
 355 {
 356         u8 op_reg_class, op_channel;
 357         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 358                 return 0;
 359         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 360                                      op_channel);
 361 }
 362
 363
 364 int p2p_supported_freq_go(struct p2p_data *p2p, unsigned int freq)
 365 {
 366         u8 op_reg_class, op_channel;
 367         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 368                 return 0;
 369         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 370                                      op_channel) &&
 371                 !freq_range_list_includes(&p2p->no_go_freq, freq);
 372 }
 373
 374
 375 int p2p_supported_freq_cli(struct p2p_data *p2p, unsigned int freq)
 376 {
 377         u8 op_reg_class, op_channel;
 378         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 379                 return 0;
 380         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 381                                      op_channel) ||
 382                 p2p_channels_includes(&p2p->cfg->cli_channels, op_reg_class,
 383                                       op_channel);
 384 }
 385
 386
 387 unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
 388                                const struct p2p_channels *channels)
 389 {
 390         unsigned int i;
 391         int freq = 0;
 392         const struct p2p_channels *tmpc = channels ?
 393                 channels : &p2p->cfg->channels;
 394
 395         if (tmpc == NULL)
 396                 return 0;
 397
 398         for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {
 399                 freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,
 400                                            p2p->cfg->pref_chan[i].chan);
 401                 if (p2p_channels_includes_freq(tmpc, freq))
 402                         return freq;
 403         }
 404         return 0;
 405 }
 406
 407
 408 void p2p_channels_dump(struct p2p_data *p2p, const char *title,
 409                        const struct p2p_channels *chan)
 410 {
 411         char buf[500], *pos, *end;
 412         size_t i, j;
 413         int ret;
 414
 415         pos = buf;
 416         end = pos + sizeof(buf);
 417
 418         for (i = 0; i < chan->reg_classes; i++) {
 419                 const struct p2p_reg_class *c;
 420                 c = &chan->reg_class[i];
 421                 ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
 422                 if (ret < 0 || ret >= end - pos)
 423                         break;
 424                 pos += ret;
 425
 426                 for (j = 0; j < c->channels; j++) {
 427                         ret = os_snprintf(pos, end - pos, "%s%u",
 428                                           j == 0 ? "" : ",",
 429                                           c->channel[j]);
 430                         if (ret < 0 || ret >= end - pos)
 431                                 break;
 432                         pos += ret;
 433                 }
 434         }
 435         *pos = '\0';
 436
 437         p2p_dbg(p2p, "%s:%s", title, buf);
 438 }
 439
 440
 441 static u8 p2p_channel_pick_random(const u8 *channels, unsigned int num_channels)
 442 {
 443         unsigned int r;
 444         if (os_get_random((u8 *) &r, sizeof(r)) < 0)
 445                 r = 0;
 446         r %= num_channels;
 447         return channels[r];
 448 }
 449
 450
 451 int p2p_channel_select(struct p2p_channels *chans, const int *classes,
 452                        u8 *op_class, u8 *op_channel)
 453 {
 454         unsigned int i, j;
 455
 456         for (j = 0; classes == NULL || classes[j]; j++) {
 457                 for (i = 0; i < chans->reg_classes; i++) {
 458                         struct p2p_reg_class *c = &chans->reg_class[i];
 459
 460                         if (c->channels == 0)
 461                                 continue;
 462
 463                         if (classes == NULL || c->reg_class == classes[j]) {
 464                                 /*
 465                                  * Pick one of the available channels in the
 466                                  * operating class at random.
 467                                  */
 468                                 *op_class = c->reg_class;
 469                                 *op_channel = p2p_channel_pick_random(
 470                                         c->channel, c->channels);
 471                                 return 0;
 472                         }
 473                 }
 474                 if (classes == NULL)
 475                         break;
 476         }
 477
 478         return -1;
 479 }
 480
 481
 482 int p2p_channel_random_social(struct p2p_channels *chans, u8 *op_class,
 483                               u8 *op_channel)
 484 {
 485         u8 chan[3];
 486         unsigned int num_channels = 0;
 487
 488         /* Try to find available social channels from 2.4 GHz */
 489         if (p2p_channels_includes(chans, 81, 1))
 490                 chan[num_channels++] = 1;
 491         if (p2p_channels_includes(chans, 81, 6))
 492                 chan[num_channels++] = 6;
 493         if (p2p_channels_includes(chans, 81, 11))
 494                 chan[num_channels++] = 11;
 495
 496         if (num_channels == 0)
 497                 return -1;
 498
 499         *op_class = 81;
 500         *op_channel = p2p_channel_pick_random(chan, num_channels);
 501
 502         return 0;
 503 }