p2p_utils.c revision a0d265f81180f341d22511538fa18166e1bbce9f
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 */ 24int 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 */ 55int 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 */ 112int 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 152static 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 */ 184void 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 211static 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 */ 236void 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 274void 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 */ 317int 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 334int 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 350int 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 360int 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 371int 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 383unsigned 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 411void 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 444int 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} 472