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         }
  98         return -1;
  99 }
 100
 101
 102 /**
 103  * p2p_freq_to_channel - Convert frequency into channel info
 104  * @op_class: Buffer for returning operating class
 105  * @channel: Buffer for returning channel number
 106  * Returns: 0 on success, -1 if the specified frequency is unknown
 107  */
 108 int p2p_freq_to_channel(unsigned int freq, u8 *op_class, u8 *channel)
 109 {
 110         /* TODO: more operating classes */
 111         if (freq >= 2412 && freq <= 2472) {
 112                 if ((freq - 2407) % 5)
 113                         return -1;
 114
 115                 *op_class = 81; /* 2.407 GHz, channels 1..13 */
 116                 *channel = (freq - 2407) / 5;
 117                 return 0;
 118         }
 119
 120         if (freq == 2484) {
 121                 *op_class = 82; /* channel 14 */
 122                 *channel = 14;
 123                 return 0;
 124         }
 125
 126         if (freq >= 5180 && freq <= 5240) {
 127                 if ((freq - 5000) % 5)
 128                         return -1;
 129
 130                 *op_class = 115; /* 5 GHz, channels 36..48 */
 131                 *channel = (freq - 5000) / 5;
 132                 return 0;
 133         }
 134
 135         if (freq >= 5745 && freq <= 5805) {
 136                 if ((freq - 5000) % 5)
 137                         return -1;
 138
 139                 *op_class = 124; /* 5 GHz, channels 149..161 */
 140                 *channel = (freq - 5000) / 5;
 141                 return 0;
 142         }
 143
 144         return -1;
 145 }
 146
 147
 148 static void p2p_reg_class_intersect(const struct p2p_reg_class *a,
 149                                     const struct p2p_reg_class *b,
 150                                     struct p2p_reg_class *res)
 151 {
 152         size_t i, j;
 153
 154         res->reg_class = a->reg_class;
 155
 156         for (i = 0; i < a->channels; i++) {
 157                 for (j = 0; j < b->channels; j++) {
 158                         if (a->channel[i] != b->channel[j])
 159                                 continue;
 160                         res->channel[res->channels] = a->channel[i];
 161                         res->channels++;
 162                         if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)
 163                                 return;
 164                 }
 165         }
 166 }
 167
 168
 169 /**
 170  * p2p_channels_intersect - Intersection of supported channel lists
 171  * @a: First set of supported channels
 172  * @b: Second set of supported channels
 173  * @res: Data structure for returning the intersection of support channels
 174  *
 175  * This function can be used to find a common set of supported channels. Both
 176  * input channels sets are assumed to use the same country code. If different
 177  * country codes are used, the regulatory class numbers may not be matched
 178  * correctly and results are undefined.
 179  */
 180 void p2p_channels_intersect(const struct p2p_channels *a,
 181                             const struct p2p_channels *b,
 182                             struct p2p_channels *res)
 183 {
 184         size_t i, j;
 185
 186         os_memset(res, 0, sizeof(*res));
 187
 188         for (i = 0; i < a->reg_classes; i++) {
 189                 const struct p2p_reg_class *a_reg = &a->reg_class[i];
 190                 for (j = 0; j < b->reg_classes; j++) {
 191                         const struct p2p_reg_class *b_reg = &b->reg_class[j];
 192                         if (a_reg->reg_class != b_reg->reg_class)
 193                                 continue;
 194                         p2p_reg_class_intersect(
 195                                 a_reg, b_reg,
 196                                 &res->reg_class[res->reg_classes]);
 197                         if (res->reg_class[res->reg_classes].channels) {
 198                                 res->reg_classes++;
 199                                 if (res->reg_classes == P2P_MAX_REG_CLASSES)
 200                                         return;
 201                         }
 202                 }
 203         }
 204 }
 205
 206
 207 /**
 208  * p2p_channels_includes - Check whether a channel is included in the list
 209  * @channels: List of supported channels
 210  * @reg_class: Regulatory class of the channel to search
 211  * @channel: Channel number of the channel to search
 212  * Returns: 1 if channel was found or 0 if not
 213  */
 214 int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,
 215                           u8 channel)
 216 {
 217         size_t i, j;
 218         for (i = 0; i < channels->reg_classes; i++) {
 219                 const struct p2p_reg_class *reg = &channels->reg_class[i];
 220                 if (reg->reg_class != reg_class)
 221                         continue;
 222                 for (j = 0; j < reg->channels; j++) {
 223                         if (reg->channel[j] == channel)
 224                                 return 1;
 225                 }
 226         }
 227         return 0;
 228 }
 229
 230
 231 int p2p_channels_includes_freq(const struct p2p_channels *channels,
 232                                unsigned int freq)
 233 {
 234         size_t i, j;
 235         for (i = 0; i < channels->reg_classes; i++) {
 236                 const struct p2p_reg_class *reg = &channels->reg_class[i];
 237                 for (j = 0; j < reg->channels; j++) {
 238                         if (p2p_channel_to_freq(reg->reg_class,
 239                                                 reg->channel[j]) == (int) freq)
 240                                 return 1;
 241                 }
 242         }
 243         return 0;
 244 }
 245
 246
 247 int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
 248 {
 249         u8 op_reg_class, op_channel;
 250         if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
 251                 return 0;
 252         return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
 253                                      op_channel);
 254 }
 255
 256
 257 unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
 258                                const struct p2p_channels *channels)
 259 {
 260         unsigned int i;
 261         int freq = 0;
 262
 263         if (channels == NULL) {
 264                 if (p2p->cfg->num_pref_chan) {
 265                         freq = p2p_channel_to_freq(
 266                                 p2p->cfg->pref_chan[0].op_class,
 267                                 p2p->cfg->pref_chan[0].chan);
 268                         if (freq < 0)
 269                                 freq = 0;
 270                 }
 271                 return freq;
 272         }
 273
 274         for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {
 275                 freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,
 276                                            p2p->cfg->pref_chan[i].chan);
 277                 if (p2p_channels_includes_freq(channels, freq))
 278                         return freq;
 279         }
 280
 281         return 0;
 282 }
 283
 284
 285 void p2p_channels_dump(struct p2p_data *p2p, const char *title,
 286                        const struct p2p_channels *chan)
 287 {
 288         char buf[500], *pos, *end;
 289         size_t i, j;
 290         int ret;
 291
 292         pos = buf;
 293         end = pos + sizeof(buf);
 294
 295         for (i = 0; i < chan->reg_classes; i++) {
 296                 const struct p2p_reg_class *c;
 297                 c = &chan->reg_class[i];
 298                 ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
 299                 if (ret < 0 || ret >= end - pos)
 300                         break;
 301                 pos += ret;
 302
 303                 for (j = 0; j < c->channels; j++) {
 304                         ret = os_snprintf(pos, end - pos, "%s%u",
 305                                           j == 0 ? "" : ",",
 306                                           c->channel[j]);
 307                         if (ret < 0 || ret >= end - pos)
 308                                 break;
 309                         pos += ret;
 310                 }
 311         }
 312         *pos = '\0';
 313
 314         p2p_dbg(p2p, "%s:%s", title, buf);
 315 }