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         if (freq >= 58320 && freq <= 64800) {
 153                 if ((freq - 58320) % 2160)
 154                         return -1;
 155
 156                 *op_class = 180; /* 60 GHz, channels 1..4 */
 157                 *channel = (freq - 56160) / 2160;
 158                 return 0;
 159         }
 160
 161         return -1;
 162 }
 163
 164
 165 static void p2p_reg_class_intersect(const struct p2p_reg_class *a,
 166                                     const struct p2p_reg_class *b,
 167                                     struct p2p_reg_class *res)
 168 {
 169         size_t i, j;
 170
 171         res->reg_class = a->reg_class;
 172
 173         for (i = 0; i < a->channels; i++) {
 174                 for (j = 0; j < b->channels; j++) {
 175                         if (a->channel[i] != b->channel[j])
 176                                 continue;
 177                         res->channel[res->channels] = a->channel[i];
 178                         res->channels++;
 179                         if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)
 180                                 return;
 181                 }
 182         }
 183 }
 184
 185
 186 /**
 187  * p2p_channels_intersect - Intersection of supported channel lists
 188  * @a: First set of supported channels
 189  * @b: Second set of supported channels
 190  * @res: Data structure for returning the intersection of support channels
 191  *
 192  * This function can be used to find a common set of supported channels. Both
 193  * input channels sets are assumed to use the same country code. If different
 194  * country codes are used, the regulatory class numbers may not be matched
 195  * correctly and results are undefined.
 196  */
 197 void p2p_channels_intersect(const struct p2p_channels *a,
 198                             const struct p2p_channels *b,
 199                             struct p2p_channels *res)
 200 {
 201         size_t i, j;
 202
 203         os_memset(res, 0, sizeof(*res));
 204
 205         for (i = 0; i < a->reg_classes; i++) {
 206                 const struct p2p_reg_class *a_reg = &a->reg_class[i];
 207                 for (j = 0; j < b->reg_classes; j++) {
 208                         const struct p2p_reg_class *b_reg = &b->reg_class[j];
 209                         if (a_reg->reg_class != b_reg->reg_class)
 210                                 continue;
 211                         p2p_reg_class_intersect(
 212                                 a_reg, b_reg,
 213                                 &res->reg_class[res->reg_classes]);
 214                         if (res->reg_class[res->reg_classes].channels) {
 215                                 res->reg_classes++;
 216                                 if (res->reg_classes == P2P_MAX_REG_CLASSES)
 217                                         return;
 218                         }
 219                 }
 220         }
 221 }
 222
 223
 224 static void p2p_op_class_union(struct p2p_reg_class *cl,
 225                                const struct p2p_reg_class *b_cl)
 226 {
 227         size_t i, j;
 228
 229         for (i = 0; i < b_cl->channels; i++) {
 230                 for (j = 0; j < cl->channels; j++) {
 231                         if (b_cl->channel[i] == cl->channel[j])
 232                                 break;
 233                 }
 234                 if (j == cl->channels) {
 235                         if (cl->channels == P2P_MAX_REG_CLASS_CHANNELS)
 236                                 return;
 237                         cl->channel[cl->channels++] = b_cl->channel[i];
 238                 }
 239         }
 240 }
 241
 242
 243 /**
 244  * p2p_channels_union - Union of channel lists
 245  * @a: First set of channels
 246  * @b: Second set of channels
 247  * @res: Data structure for returning the union of channels
 248  */
 249 void p2p_channels_union(const struct p2p_channels *a,
 250                         const struct p2p_channels *b,
 251                         struct p2p_channels *res)
 252 {
 253         size_t i, j;
 254
 255         if (a != res)
 256                 os_memcpy(res, a, sizeof(*res));
 257
 258         for (i = 0; i < res->reg_classes; i++) {
 259                 struct p2p_reg_class *cl = &res->reg_class[i];
 260                 for (j = 0; j < b->reg_classes; j++) {
 261                         const struct p2p_reg_class *b_cl = &b->reg_class[j];
 262                         if (cl->reg_class != b_cl->reg_class)
 263                                 continue;
 264                         p2p_op_class_union(cl, b_cl);
 265                 }
 266         }
 267
 268         for (j = 0; j < b->reg_classes; j++) {
 269                 const struct p2p_reg_class *b_cl = &b->reg_class[j];
 270
 271                 for (i = 0; i < res->reg_classes; i++) {
 272                         struct p2p_reg_class *cl = &res->reg_class[i];
 273                         if (cl->reg_class == b_cl->reg_class)
 274                                 break;
 275                 }
 276
 277                 if (i == res->reg_classes) {
 278                         if (res->reg_classes == P2P_MAX_REG_CLASSES)
 279                                 return;
 280                         os_memcpy(&res->reg_class[res->reg_classes++],
 281                                   b_cl, sizeof(struct p2p_reg_class));
 282                 }
 283         }
 284 }
 285
 286
 287 void p2p_channels_remove_freqs(struct p2p_channels *chan,
 288                                const struct wpa_freq_range_list *list)
 289 {
 290         size_t o, c;
 291
 292         if (list == NULL)
 293                 return;
 294
 295         o = 0;
 296         while (o < chan->reg_classes) {
 297                 struct p2p_reg_class *op = &chan->reg_class[o];
 298
 299                 c = 0;
 300                 while (c < op->channels) {
 301                         int freq = p2p_channel_to_freq(op->reg_class,
 302                                                        op->channel[c]);
 303                         if (freq > 0 && freq_range_list_includes(list, freq)) {
 304                                 op->channels--;
 305                                 os_memmove(&op->channel[c],
 306                                            &op->channel[c + 1],
 307                                            op->channels - c);
 308                         } else
 309                                 c++;
 310                 }
 311
 312                 if (op->channels == 0) {
 313                         chan->reg_classes--;
 314                         os_memmove(&chan->reg_class[o], &chan->reg_class[o + 1],
 315                                    (chan->reg_classes - o) *
 316                                    sizeof(struct p2p_reg_class));
 317                 } else
 318                         o++;
 319         }
 320 }
 321
 322
 323 /**
 324  * p2p_channels_includes - Check whether a channel is included in the list
 325  * @channels: List of supported channels
 326  * @reg_class: Regulatory class of the channel to search
 327  * @channel: Channel number of the channel to search
 328  * Returns: 1 if channel was found or 0 if not
 329  */
 330 int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,
 331                           u8 channel)
 332 {
 333         size_t i, j;
 334         for (i = 0; i < channels->reg_classes; i++) {
 335                 const struct p2p_reg_class *reg = &channels->reg_class[i];
 336                 if (reg->reg_class != reg_class)
 337                         continue;
 338                 for (j = 0; j < reg->channels; j++) {
 339                         if (reg->channel[j] == channel)
 340                                 return 1;
 341                 }
 342         }
 343         return 0;
 344 }
 345
 346
 347 int p2p_channels_includes_freq(const struct p2p_channels *channels,
 348                                unsigned int freq)
 349 {
 350         size_t i, j;
 351         for (i = 0; i < channels->reg_classes; i++) {
 352                 const struct p2p_reg_class *reg = &channels->reg_class[i];
 353                 for (j = 0; j < reg->channels; j++) {
 354                         if (p2p_channel_to_freq(reg->reg_class,
 355                                                 reg->channel[j]) == (int) freq)
 356                                 return 1;
 357                 }
 358         }
 359         return 0;
 360 }
 361
 362
 363 int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
 364 {
 365         u8 op_reg_class, op_channel;
 366         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 367                 return 0;
 368         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 369                                      op_channel);
 370 }
 371
 372
 373 int p2p_supported_freq_go(struct p2p_data *p2p, unsigned int freq)
 374 {
 375         u8 op_reg_class, op_channel;
 376         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 377                 return 0;
 378         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 379                                      op_channel) &&
 380                 !freq_range_list_includes(&p2p->no_go_freq, freq);
 381 }
 382
 383
 384 int p2p_supported_freq_cli(struct p2p_data *p2p, unsigned int freq)
 385 {
 386         u8 op_reg_class, op_channel;
 387         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 388                 return 0;
 389         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 390                                      op_channel) ||
 391                 p2p_channels_includes(&p2p->cfg->cli_channels, op_reg_class,
 392                                       op_channel);
 393 }
 394
 395
 396 unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
 397                                const struct p2p_channels *channels)
 398 {
 399         unsigned int i;
 400         int freq = 0;
 401         const struct p2p_channels *tmpc = channels ?
 402                 channels : &p2p->cfg->channels;
 403
 404         if (tmpc == NULL)
 405                 return 0;
 406
 407         for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {
 408                 freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,
 409                                            p2p->cfg->pref_chan[i].chan);
 410                 if (p2p_channels_includes_freq(tmpc, freq))
 411                         return freq;
 412         }
 413         return 0;
 414 }
 415
 416
 417 void p2p_channels_dump(struct p2p_data *p2p, const char *title,
 418                        const struct p2p_channels *chan)
 419 {
 420         char buf[500], *pos, *end;
 421         size_t i, j;
 422         int ret;
 423
 424         pos = buf;
 425         end = pos + sizeof(buf);
 426
 427         for (i = 0; i < chan->reg_classes; i++) {
 428                 const struct p2p_reg_class *c;
 429                 c = &chan->reg_class[i];
 430                 ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
 431                 if (ret < 0 || ret >= end - pos)
 432                         break;
 433                 pos += ret;
 434
 435                 for (j = 0; j < c->channels; j++) {
 436                         ret = os_snprintf(pos, end - pos, "%s%u",
 437                                           j == 0 ? "" : ",",
 438                                           c->channel[j]);
 439                         if (ret < 0 || ret >= end - pos)
 440                                 break;
 441                         pos += ret;
 442                 }
 443         }
 444         *pos = '\0';
 445
 446         p2p_dbg(p2p, "%s:%s", title, buf);
 447 }
 448
 449
 450 static u8 p2p_channel_pick_random(const u8 *channels, unsigned int num_channels)
 451 {
 452         unsigned int r;
 453         if (os_get_random((u8 *) &r, sizeof(r)) < 0)
 454                 r = 0;
 455         r %= num_channels;
 456         return channels[r];
 457 }
 458
 459
 460 int p2p_channel_select(struct p2p_channels *chans, const int *classes,
 461                        u8 *op_class, u8 *op_channel)
 462 {
 463         unsigned int i, j;
 464
 465         for (j = 0; classes == NULL || classes[j]; j++) {
 466                 for (i = 0; i < chans->reg_classes; i++) {
 467                         struct p2p_reg_class *c = &chans->reg_class[i];
 468
 469                         if (c->channels == 0)
 470                                 continue;
 471
 472                         if (classes == NULL || c->reg_class == classes[j]) {
 473                                 /*
 474                                  * Pick one of the available channels in the
 475                                  * operating class at random.
 476                                  */
 477                                 *op_class = c->reg_class;
 478                                 *op_channel = p2p_channel_pick_random(
 479                                         c->channel, c->channels);
 480                                 return 0;
 481                         }
 482                 }
 483                 if (classes == NULL)
 484                         break;
 485         }
 486
 487         return -1;
 488 }
 489
 490
 491 int p2p_channel_random_social(struct p2p_channels *chans, u8 *op_class,
 492                               u8 *op_channel)
 493 {
 494         u8 chan[4];
 495         unsigned int num_channels = 0;
 496
 497         /* Try to find available social channels from 2.4 GHz */
 498         if (p2p_channels_includes(chans, 81, 1))
 499                 chan[num_channels++] = 1;
 500         if (p2p_channels_includes(chans, 81, 6))
 501                 chan[num_channels++] = 6;
 502         if (p2p_channels_includes(chans, 81, 11))
 503                 chan[num_channels++] = 11;
 504
 505         /* Try to find available social channels from 60 GHz */
 506         if (p2p_channels_includes(chans, 180, 2))
 507                 chan[num_channels++] = 2;
 508
 509         if (num_channels == 0)
 510                 return -1;
 511
 512         *op_channel = p2p_channel_pick_random(chan, num_channels);
 513         if (*op_channel == 2)
 514                 *op_class = 180;
 515         else
 516                 *op_class = 81;
 517
 518         return 0;
 519 }