intersect.c

   1 #include <errno.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include <sys/mman.h>
   5 #include <sys/stat.h>
   6 #include <fcntl.h>
   7 #include <arpa/inet.h> /* ntohl */
   8 #include <string.h>
   9
  10 #include "reglib.h"
  11
  12 /* Intersects regulatory domains, this will skip any regulatory marked with
  13  * an alpha2 of '00', which is used to indicate a regulatory domain */
  14
  15 #define BUG_ON(foo) do { \
  16         if (foo) { \
  17                 printf("BUG\n"); \
  18                 exit(-1); \
  19         } \
  20         } while (0)
  21
  22 /* Helper for regdom_intersect(), this does the real
  23  * mathematical intersection fun */
  24 static int reg_rules_intersect(
  25         struct ieee80211_reg_rule *rule1,
  26         struct ieee80211_reg_rule *rule2,
  27         struct ieee80211_reg_rule *intersected_rule)
  28 {
  29         struct ieee80211_freq_range *freq_range1, *freq_range2, *freq_range;
  30         struct ieee80211_power_rule *power_rule1, *power_rule2, *power_rule;
  31         __u32 freq_diff;
  32
  33         freq_range1 = &rule1->freq_range;
  34         freq_range2 = &rule2->freq_range;
  35         freq_range = &intersected_rule->freq_range;
  36
  37         power_rule1 = &rule1->power_rule;
  38         power_rule2 = &rule2->power_rule;
  39         power_rule = &intersected_rule->power_rule;
  40
  41         freq_range->start_freq_khz = max(freq_range1->start_freq_khz,
  42                 freq_range2->start_freq_khz);
  43         freq_range->end_freq_khz = min(freq_range1->end_freq_khz,
  44                 freq_range2->end_freq_khz);
  45         freq_range->max_bandwidth_khz = min(freq_range1->max_bandwidth_khz,
  46                 freq_range2->max_bandwidth_khz);
  47
  48         freq_diff = freq_range->end_freq_khz - freq_range->start_freq_khz;
  49         if (freq_range->max_bandwidth_khz > freq_diff)
  50                 freq_range->max_bandwidth_khz = freq_diff;
  51
  52         power_rule->max_eirp = min(power_rule1->max_eirp,
  53                 power_rule2->max_eirp);
  54         power_rule->max_antenna_gain = min(power_rule1->max_antenna_gain,
  55                 power_rule2->max_antenna_gain);
  56
  57         intersected_rule->flags = (rule1->flags | rule2->flags);
  58
  59         if (!is_valid_reg_rule(intersected_rule))
  60                 return -EINVAL;
  61
  62         return 0;
  63 }
  64
  65 /**
  66  * regdom_intersect - do the intersection between two regulatory domains
  67  * @rd1: first regulatory domain
  68  * @rd2: second regulatory domain
  69  *
  70  * Use this function to get the intersection between two regulatory domains.
  71  * Once completed we will mark the alpha2 for the rd as intersected, "98",
  72  * as no one single alpha2 can represent this regulatory domain.
  73  *
  74  * Returns a pointer to the regulatory domain structure which will hold the
  75  * resulting intersection of rules between rd1 and rd2. We will
  76  * malloc() this structure for you.
  77  */
  78 struct ieee80211_regdomain *regdom_intersect(
  79         struct ieee80211_regdomain *rd1,
  80         struct ieee80211_regdomain *rd2)
  81 {
  82         int r, size_of_regd;
  83         unsigned int x, y;
  84         unsigned int num_rules = 0, rule_idx = 0;
  85         struct ieee80211_reg_rule *rule1, *rule2, *intersected_rule;
  86         struct ieee80211_regdomain *rd;
  87         /* This is just a dummy holder to help us count */
  88         struct ieee80211_reg_rule irule;
  89
  90         /* Uses the stack temporarily for counter arithmetic */
  91         intersected_rule = &irule;
  92
  93         memset(intersected_rule, 0, sizeof(struct ieee80211_reg_rule));
  94
  95         if (!rd1 || !rd2) {
  96                 fprintf(stderr, "rd1 or or rd2 is null\n");
  97                 return NULL;
  98         }
  99
 100         /* First we get a count of the rules we'll need, then we actually
 101          * build them. This is to so we can malloc() and free() a
 102          * regdomain once. The reason we use reg_rules_intersect() here
 103          * is it will return -EINVAL if the rule computed makes no sense.
 104          * All rules that do check out OK are valid. */
 105
 106         for (x = 0; x < rd1->n_reg_rules; x++) {
 107                 rule1 = &rd1->reg_rules[x];
 108                 for (y = 0; y < rd2->n_reg_rules; y++) {
 109                         rule2 = &rd2->reg_rules[y];
 110                         if (!reg_rules_intersect(rule1, rule2,
 111                                         intersected_rule))
 112                                 num_rules++;
 113                         memset(intersected_rule, 0,
 114                                         sizeof(struct ieee80211_reg_rule));
 115                 }
 116         }
 117
 118         if (!num_rules) {
 119                 fprintf(stderr, "error: num_rules == 0\n");
 120                 return NULL;
 121         }
 122
 123         size_of_regd = sizeof(struct ieee80211_regdomain) +
 124                 ((num_rules + 1) * sizeof(struct ieee80211_reg_rule));
 125
 126         rd = malloc(size_of_regd);
 127         if (!rd) {
 128                 fprintf(stderr, "no memory left\n");
 129                 return NULL;
 130         }
 131
 132         memset(rd, 0, size_of_regd);
 133
 134         for (x = 0; x < rd1->n_reg_rules; x++) {
 135                 rule1 = &rd1->reg_rules[x];
 136                 for (y = 0; y < rd2->n_reg_rules; y++) {
 137                         rule2 = &rd2->reg_rules[y];
 138                         /* This time around instead of using the stack lets
 139                          * write to the target rule directly saving ourselves
 140                          * a memcpy() */
 141                         intersected_rule = &rd->reg_rules[rule_idx];
 142                         r = reg_rules_intersect(rule1, rule2,
 143                                 intersected_rule);
 144                         if (r)
 145                                 continue;
 146                         rule_idx++;
 147                 }
 148         }
 149
 150         if (rule_idx != num_rules) {
 151                 fprintf(stderr, "Error while doing regdom interesection :(\n");
 152                 free(rd);
 153                 return NULL;
 154         }
 155
 156         rd->n_reg_rules = num_rules;
 157         rd->alpha2[0] = '9';
 158         rd->alpha2[1] = '9';
 159
 160         return rd;
 161 }
 162
 163 int main(int argc, char **argv)
 164 {
 165         int fd;
 166         struct stat stat;
 167         __u8 *db;
 168         struct regdb_file_header *header;
 169         struct regdb_file_reg_country *countries;
 170         int dblen, siglen, num_countries, i, r = 0;
 171         struct ieee80211_regdomain *prev_world = NULL, *rd = NULL, *world = NULL;
 172         int intersected = 0;
 173
 174         if (argc != 2) {
 175                 fprintf(stderr, "Usage: %s <filename>\n", argv[0]);
 176                 return 2;
 177         }
 178
 179         fd = open(argv[1], O_RDONLY);
 180         if (fd < 0) {
 181                 perror("failed to open db file");
 182                 return 2;
 183         }
 184
 185         if (fstat(fd, &stat)) {
 186                 perror("failed to fstat db file");
 187                 return 2;
 188         }
 189
 190         dblen = stat.st_size;
 191
 192         db = mmap(NULL, dblen, PROT_READ, MAP_PRIVATE, fd, 0);
 193         if (db == MAP_FAILED) {
 194                 perror("failed to mmap db file");
 195                 return 2;
 196         }
 197
 198         header = crda_get_file_ptr(db, dblen, sizeof(*header), 0);
 199
 200         if (ntohl(header->magic) != REGDB_MAGIC) {
 201                 fprintf(stderr, "Invalid database magic\n");
 202                 return 2;
 203         }
 204
 205         if (ntohl(header->version) != REGDB_VERSION) {
 206                 fprintf(stderr, "Invalid database version\n");
 207                 return 2;
 208         }
 209
 210         siglen = ntohl(header->signature_length);
 211         /* adjust dblen so later sanity checks don't run into the signature */
 212         dblen -= siglen;
 213
 214         if (dblen <= (int)sizeof(*header)) {
 215                 fprintf(stderr, "Invalid signature length %d\n", siglen);
 216                 return 2;
 217         }
 218
 219         /* verify signature */
 220         if (!crda_verify_db_signature(db, dblen, siglen))
 221                 return -EINVAL;
 222
 223         num_countries = ntohl(header->reg_country_num);
 224
 225         if (num_countries <= 0)
 226                 return 0;
 227
 228         countries = crda_get_file_ptr(db, dblen,
 229                         sizeof(struct regdb_file_reg_country) * num_countries,
 230                         header->reg_country_ptr);
 231
 232         /* We intersect only when we have to rd structures ready */
 233         for (i = 0; i < num_countries; i++) {
 234                 struct regdb_file_reg_country *country = countries + i;
 235
 236                 if (is_world_regdom((const char *) country->alpha2))
 237                         continue;
 238
 239                 /* Gets the rd for the current country */
 240                 rd = country2rd(db, dblen, country);
 241                 if (!rd) {
 242                         r = -ENOMEM;
 243                         fprintf(stderr, "Could not covert country "
 244                                 "(%.2s) to rd\n", country->alpha2);
 245                         goto out;
 246                 }
 247
 248                 if (num_countries == 1) {
 249                         world = rd;
 250                         rd = NULL;
 251                         break;
 252                 }
 253
 254                 if (!prev_world) {
 255                         prev_world = rd;
 256                         continue;
 257                 }
 258
 259
 260                 if (world) {
 261                         free(prev_world);
 262                         prev_world = world;
 263                 }
 264
 265                 world = regdom_intersect(prev_world, rd);
 266                 if (!world) {
 267                         /* Could be something else but we'll live with this */
 268                         r = -ENOMEM;
 269                         if (intersected)
 270                                 fprintf(stderr, "Could not intersect world "
 271                                         "with country (%.2s)\n",
 272                                         rd->alpha2);
 273                         else
 274                                 fprintf(stderr, "Could not intersect country (%.2s) "
 275                                         "with country (%.2s)\n",
 276                                         prev_world->alpha2,
 277                                         rd->alpha2);
 278                         goto out;
 279                 }
 280
 281                 if (intersected)
 282                         /* Use UTF-8 Intersection symbol ? (0xE2,0x88,0xA9) :) */
 283                         printf("WW (%d) intersect %c%c (%d) ==> %d rules\n",
 284                                 prev_world->n_reg_rules,
 285                                 rd->alpha2[0],
 286                                 rd->alpha2[1],
 287                                 rd->n_reg_rules,
 288                                 world->n_reg_rules);
 289                 else
 290                         printf("%c%c (%d) intersect %c%c (%d) ==> %d rules\n",
 291                                 prev_world->alpha2[0],
 292                                 prev_world->alpha2[1],
 293                                 prev_world->n_reg_rules,
 294                                 rd->alpha2[0],
 295                                 rd->alpha2[1],
 296                                 rd->n_reg_rules,
 297                                 world->n_reg_rules);
 298                 intersected++;
 299         }
 300
 301         if (intersected > 1)
 302                 printf("%d regulatory domains intersected\n", intersected);
 303         else
 304                 printf("Only one intersection completed\n");
 305
 306         /* Tada! */
 307         printf("== World regulatory domain: ==\n");
 308         print_regdom(world);
 309
 310 out:
 311         if (!intersected) {
 312                 free(world);
 313                 return r;
 314         }
 315         if (intersected > 1) {
 316                 free(rd);
 317                 free(prev_world);
 318         }
 319         free(world);
 320         return r;
 321 }