contrib/hostapd/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         }
 102         return -1;
 103 }
 104
 105
 106 /**
 107  * p2p_freq_to_channel - Convert frequency into channel info
 108  * @op_class: Buffer for returning operating class
 109  * @channel: Buffer for returning channel number
 110  * Returns: 0 on success, -1 if the specified frequency is unknown
 111  */
 112 int p2p_freq_to_channel(unsigned int freq, u8 *op_class, u8 *channel)
 113 {
 114         /* TODO: more operating classes */
 115         if (freq >= 2412 && freq <= 2472) {
 116                 if ((freq - 2407) % 5)
 117                         return -1;
 118
 119                 *op_class = 81; /* 2.407 GHz, channels 1..13 */
 120                 *channel = (freq - 2407) / 5;
 121                 return 0;
 122         }
 123
 124         if (freq == 2484) {
 125                 *op_class = 82; /* channel 14 */
 126                 *channel = 14;
 127                 return 0;
 128         }
 129
 130         if (freq >= 5180 && freq <= 5240) {
 131                 if ((freq - 5000) % 5)
 132                         return -1;
 133
 134                 *op_class = 115; /* 5 GHz, channels 36..48 */
 135                 *channel = (freq - 5000) / 5;
 136                 return 0;
 137         }
 138
 139         if (freq >= 5745 && freq <= 5805) {
 140                 if ((freq - 5000) % 5)
 141                         return -1;
 142
 143                 *op_class = 124; /* 5 GHz, channels 149..161 */
 144                 *channel = (freq - 5000) / 5;
 145                 return 0;
 146         }
 147
 148         return -1;
 149 }
 150
 151
 152 static void p2p_reg_class_intersect(const struct p2p_reg_class *a,
 153                                     const struct p2p_reg_class *b,
 154                                     struct p2p_reg_class *res)
 155 {
 156         size_t i, j;
 157
 158         res->reg_class = a->reg_class;
 159
 160         for (i = 0; i < a->channels; i++) {
 161                 for (j = 0; j < b->channels; j++) {
 162                         if (a->channel[i] != b->channel[j])
 163                                 continue;
 164                         res->channel[res->channels] = a->channel[i];
 165                         res->channels++;
 166                         if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)
 167                                 return;
 168                 }
 169         }
 170 }
 171
 172
 173 /**
 174  * p2p_channels_intersect - Intersection of supported channel lists
 175  * @a: First set of supported channels
 176  * @b: Second set of supported channels
 177  * @res: Data structure for returning the intersection of support channels
 178  *
 179  * This function can be used to find a common set of supported channels. Both
 180  * input channels sets are assumed to use the same country code. If different
 181  * country codes are used, the regulatory class numbers may not be matched
 182  * correctly and results are undefined.
 183  */
 184 void p2p_channels_intersect(const struct p2p_channels *a,
 185                             const struct p2p_channels *b,
 186                             struct p2p_channels *res)
 187 {
 188         size_t i, j;
 189
 190         os_memset(res, 0, sizeof(*res));
 191
 192         for (i = 0; i < a->reg_classes; i++) {
 193                 const struct p2p_reg_class *a_reg = &a->reg_class[i];
 194                 for (j = 0; j < b->reg_classes; j++) {
 195                         const struct p2p_reg_class *b_reg = &b->reg_class[j];
 196                         if (a_reg->reg_class != b_reg->reg_class)
 197                                 continue;
 198                         p2p_reg_class_intersect(
 199                                 a_reg, b_reg,
 200                                 &res->reg_class[res->reg_classes]);
 201                         if (res->reg_class[res->reg_classes].channels) {
 202                                 res->reg_classes++;
 203                                 if (res->reg_classes == P2P_MAX_REG_CLASSES)
 204                                         return;
 205                         }
 206                 }
 207         }
 208 }
 209
 210
 211 static void p2p_op_class_union(struct p2p_reg_class *cl,
 212                                const struct p2p_reg_class *b_cl)
 213 {
 214         size_t i, j;
 215
 216         for (i = 0; i < b_cl->channels; i++) {
 217                 for (j = 0; j < cl->channels; j++) {
 218                         if (b_cl->channel[i] == cl->channel[j])
 219                                 break;
 220                 }
 221                 if (j == cl->channels) {
 222                         if (cl->channels == P2P_MAX_REG_CLASS_CHANNELS)
 223                                 return;
 224                         cl->channel[cl->channels++] = b_cl->channel[i];
 225                 }
 226         }
 227 }
 228
 229
 230 /**
 231  * p2p_channels_union - Union of channel lists
 232  * @a: First set of channels
 233  * @b: Second set of channels
 234  * @res: Data structure for returning the union of channels
 235  */
 236 void p2p_channels_union(const struct p2p_channels *a,
 237                         const struct p2p_channels *b,
 238                         struct p2p_channels *res)
 239 {
 240         size_t i, j;
 241
 242         if (a != res)
 243                 os_memcpy(res, a, sizeof(*res));
 244
 245         for (i = 0; i < res->reg_classes; i++) {
 246                 struct p2p_reg_class *cl = &res->reg_class[i];
 247                 for (j = 0; j < b->reg_classes; j++) {
 248                         const struct p2p_reg_class *b_cl = &b->reg_class[j];
 249                         if (cl->reg_class != b_cl->reg_class)
 250                                 continue;
 251                         p2p_op_class_union(cl, b_cl);
 252                 }
 253         }
 254
 255         for (j = 0; j < b->reg_classes; j++) {
 256                 const struct p2p_reg_class *b_cl = &b->reg_class[j];
 257
 258                 for (i = 0; i < res->reg_classes; i++) {
 259                         struct p2p_reg_class *cl = &res->reg_class[i];
 260                         if (cl->reg_class == b_cl->reg_class)
 261                                 break;
 262                 }
 263
 264                 if (i == res->reg_classes) {
 265                         if (res->reg_classes == P2P_MAX_REG_CLASSES)
 266                                 return;
 267                         os_memcpy(&res->reg_class[res->reg_classes++],
 268                                   b_cl, sizeof(struct p2p_reg_class));
 269                 }
 270         }
 271 }
 272
 273
 274 void p2p_channels_remove_freqs(struct p2p_channels *chan,
 275                                const struct wpa_freq_range_list *list)
 276 {
 277         size_t o, c;
 278
 279         if (list == NULL)
 280                 return;
 281
 282         o = 0;
 283         while (o < chan->reg_classes) {
 284                 struct p2p_reg_class *op = &chan->reg_class[o];
 285
 286                 c = 0;
 287                 while (c < op->channels) {
 288                         int freq = p2p_channel_to_freq(op->reg_class,
 289                                                        op->channel[c]);
 290                         if (freq > 0 && freq_range_list_includes(list, freq)) {
 291                                 op->channels--;
 292                                 os_memmove(&op->channel[c],
 293                                            &op->channel[c + 1],
 294                                            op->channels - c);
 295                         } else
 296                                 c++;
 297                 }
 298
 299                 if (op->channels == 0) {
 300                         chan->reg_classes--;
 301                         os_memmove(&chan->reg_class[o], &chan->reg_class[o + 1],
 302                                    (chan->reg_classes - o) *
 303                                    sizeof(struct p2p_reg_class));
 304                 } else
 305                         o++;
 306         }
 307 }
 308
 309
 310 /**
 311  * p2p_channels_includes - Check whether a channel is included in the list
 312  * @channels: List of supported channels
 313  * @reg_class: Regulatory class of the channel to search
 314  * @channel: Channel number of the channel to search
 315  * Returns: 1 if channel was found or 0 if not
 316  */
 317 int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,
 318                           u8 channel)
 319 {
 320         size_t i, j;
 321         for (i = 0; i < channels->reg_classes; i++) {
 322                 const struct p2p_reg_class *reg = &channels->reg_class[i];
 323                 if (reg->reg_class != reg_class)
 324                         continue;
 325                 for (j = 0; j < reg->channels; j++) {
 326                         if (reg->channel[j] == channel)
 327                                 return 1;
 328                 }
 329         }
 330         return 0;
 331 }
 332
 333
 334 int p2p_channels_includes_freq(const struct p2p_channels *channels,
 335                                unsigned int freq)
 336 {
 337         size_t i, j;
 338         for (i = 0; i < channels->reg_classes; i++) {
 339                 const struct p2p_reg_class *reg = &channels->reg_class[i];
 340                 for (j = 0; j < reg->channels; j++) {
 341                         if (p2p_channel_to_freq(reg->reg_class,
 342                                                 reg->channel[j]) == (int) freq)
 343                                 return 1;
 344                 }
 345         }
 346         return 0;
 347 }
 348
 349
 350 int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
 351 {
 352         u8 op_reg_class, op_channel;
 353         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 354                 return 0;
 355         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 356                                      op_channel);
 357 }
 358
 359
 360 int p2p_supported_freq_go(struct p2p_data *p2p, unsigned int freq)
 361 {
 362         u8 op_reg_class, op_channel;
 363         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 364                 return 0;
 365         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 366                                      op_channel) &&
 367                 !freq_range_list_includes(&p2p->no_go_freq, freq);
 368 }
 369
 370
 371 int p2p_supported_freq_cli(struct p2p_data *p2p, unsigned int freq)
 372 {
 373         u8 op_reg_class, op_channel;
 374         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 375                 return 0;
 376         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 377                                      op_channel) ||
 378                 p2p_channels_includes(&p2p->cfg->cli_channels, op_reg_class,
 379                                       op_channel);
 380 }
 381
 382
 383 unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
 384                                const struct p2p_channels *channels)
 385 {
 386         unsigned int i;
 387         int freq = 0;
 388
 389         if (channels == NULL) {
 390                 if (p2p->cfg->num_pref_chan) {
 391                         freq = p2p_channel_to_freq(
 392                                 p2p->cfg->pref_chan[0].op_class,
 393                                 p2p->cfg->pref_chan[0].chan);
 394                         if (freq < 0)
 395                                 freq = 0;
 396                 }
 397                 return freq;
 398         }
 399
 400         for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {
 401                 freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,
 402                                            p2p->cfg->pref_chan[i].chan);
 403                 if (p2p_channels_includes_freq(channels, freq))
 404                         return freq;
 405         }
 406
 407         return 0;
 408 }
 409
 410
 411 void p2p_channels_dump(struct p2p_data *p2p, const char *title,
 412                        const struct p2p_channels *chan)
 413 {
 414         char buf[500], *pos, *end;
 415         size_t i, j;
 416         int ret;
 417
 418         pos = buf;
 419         end = pos + sizeof(buf);
 420
 421         for (i = 0; i < chan->reg_classes; i++) {
 422                 const struct p2p_reg_class *c;
 423                 c = &chan->reg_class[i];
 424                 ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
 425                 if (ret < 0 || ret >= end - pos)
 426                         break;
 427                 pos += ret;
 428
 429                 for (j = 0; j < c->channels; j++) {
 430                         ret = os_snprintf(pos, end - pos, "%s%u",
 431                                           j == 0 ? "" : ",",
 432                                           c->channel[j]);
 433                         if (ret < 0 || ret >= end - pos)
 434                                 break;
 435                         pos += ret;
 436                 }
 437         }
 438         *pos = '\0';
 439
 440         p2p_dbg(p2p, "%s:%s", title, buf);
 441 }
 442
 443
 444 int p2p_channel_select(struct p2p_channels *chans, const int *classes,
 445                        u8 *op_class, u8 *op_channel)
 446 {
 447         unsigned int i, j, r;
 448
 449         for (j = 0; classes[j]; j++) {
 450                 for (i = 0; i < chans->reg_classes; i++) {
 451                         struct p2p_reg_class *c = &chans->reg_class[i];
 452
 453                         if (c->channels == 0)
 454                                 continue;
 455
 456                         if (c->reg_class == classes[j]) {
 457                                 /*
 458                                  * Pick one of the available channels in the
 459                                  * operating class at random.
 460                                  */
 461                                 os_get_random((u8 *) &r, sizeof(r));
 462                                 r %= c->channels;
 463                                 *op_class = c->reg_class;
 464                                 *op_channel = c->channel[r];
 465                                 return 0;
 466                         }
 467                 }
 468         }
 469
 470         return -1;
 471 }