crda.c

   1 /*
   2  * Central Regulatory Domain Agent for Linux
   3  *
   4  * Userspace helper which sends regulatory domains to Linux via nl80211
   5  */
   6
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <sys/mman.h>
  10 #include <sys/stat.h>
  11 #include <fcntl.h>
  12 #include <arpa/inet.h>
  13
  14 #include <netlink/genl/genl.h>
  15 #include <netlink/genl/family.h>
  16 #include <netlink/genl/ctrl.h>
  17 #include <netlink/msg.h>
  18 #include <netlink/attr.h>
  19 #include <linux/nl80211.h>
  20
  21 #include "regdb.h"
  22 #include "reglib.h"
  23
  24 struct nl80211_state {
  25         struct nl_handle *nl_handle;
  26         struct nl_cache *nl_cache;
  27         struct genl_family *nl80211;
  28 };
  29
  30 static int nl80211_init(struct nl80211_state *state)
  31 {
  32         int err;
  33
  34         state->nl_handle = nl_handle_alloc();
  35         if (!state->nl_handle) {
  36                 fprintf(stderr, "Failed to allocate netlink handle.\n");
  37                 return -ENOMEM;
  38         }
  39
  40         if (genl_connect(state->nl_handle)) {
  41                 fprintf(stderr, "Failed to connect to generic netlink.\n");
  42                 err = -ENOLINK;
  43                 goto out_handle_destroy;
  44         }
  45
  46         state->nl_cache = genl_ctrl_alloc_cache(state->nl_handle);
  47         if (!state->nl_cache) {
  48                 fprintf(stderr, "Failed to allocate generic netlink cache.\n");
  49                 err = -ENOMEM;
  50                 goto out_handle_destroy;
  51         }
  52
  53         state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
  54         if (!state->nl80211) {
  55                 fprintf(stderr, "nl80211 not found.\n");
  56                 err = -ENOENT;
  57                 goto out_cache_free;
  58         }
  59
  60         return 0;
  61
  62  out_cache_free:
  63         nl_cache_free(state->nl_cache);
  64  out_handle_destroy:
  65         nl_handle_destroy(state->nl_handle);
  66         return err;
  67 }
  68
  69 static void nl80211_cleanup(struct nl80211_state *state)
  70 {
  71         genl_family_put(state->nl80211);
  72         nl_cache_free(state->nl_cache);
  73         nl_handle_destroy(state->nl_handle);
  74 }
  75
  76 static int reg_handler(struct nl_msg __attribute__((unused)) *msg,
  77                         void __attribute__((unused)) *arg)
  78 {
  79         return NL_SKIP;
  80 }
  81
  82 static int wait_handler(struct nl_msg __attribute__((unused)) *msg, void *arg)
  83 {
  84         int *finished = arg;
  85         *finished = 1;
  86         return NL_STOP;
  87 }
  88
  89 static int error_handler(struct sockaddr_nl __attribute__((unused)) *nla,
  90                             struct nlmsgerr *err,
  91                             void __attribute__((unused)) *arg)
  92 {
  93         fprintf(stderr, "nl80211 error %d\n", err->error);
  94         exit(err->error);
  95 }
  96
  97 static int put_reg_rule(__u8 *db, int dblen, __be32 ruleptr, struct nl_msg *msg)
  98 {
  99         struct regdb_file_reg_rule *rule;
 100         struct regdb_file_freq_range *freq;
 101         struct regdb_file_power_rule *power;
 102
 103         rule  = crda_get_file_ptr(db, dblen, sizeof(*rule), ruleptr);
 104         freq  = crda_get_file_ptr(db, dblen, sizeof(*freq), rule->freq_range_ptr);
 105         power = crda_get_file_ptr(db, dblen, sizeof(*power), rule->power_rule_ptr);
 106
 107         NLA_PUT_U32(msg, NL80211_ATTR_REG_RULE_FLAGS,           ntohl(rule->flags));
 108         NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_START,         ntohl(freq->start_freq));
 109         NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_END,           ntohl(freq->end_freq));
 110         NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_MAX_BW,        ntohl(freq->max_bandwidth));
 111         NLA_PUT_U32(msg, NL80211_ATTR_POWER_RULE_MAX_ANT_GAIN,  ntohl(power->max_antenna_gain));
 112         NLA_PUT_U32(msg, NL80211_ATTR_POWER_RULE_MAX_EIRP,      ntohl(power->max_eirp));
 113
 114         return 0;
 115
 116 nla_put_failure:
 117         return -1;
 118 }
 119
 120 int main(int argc, char **argv)
 121 {
 122         int fd;
 123         struct stat stat;
 124         __u8 *db;
 125         struct regdb_file_header *header;
 126         struct regdb_file_reg_country *countries;
 127         int dblen, siglen, num_countries, i, j, r;
 128         char alpha2[2];
 129         char *env_country;
 130         struct nl80211_state nlstate;
 131         struct nl_cb *cb = NULL;
 132         struct nl_msg *msg;
 133         int found_country = 0;
 134         int finished = 0;
 135
 136         struct regdb_file_reg_rules_collection *rcoll;
 137         struct regdb_file_reg_country *country;
 138         struct nlattr *nl_reg_rules;
 139         int num_rules;
 140
 141         const char regdb[] = "/usr/lib/crda/regulatory.bin";
 142
 143         if (argc != 1) {
 144                 fprintf(stderr, "Usage: %s\n", argv[0]);
 145                 return -EINVAL;
 146         }
 147
 148         env_country = getenv("COUNTRY");
 149         if (!env_country) {
 150                 fprintf(stderr, "COUNTRY environment variable not set.\n");
 151                 return -EINVAL;
 152         }
 153
 154         if (!is_valid_regdom(env_country)) {
 155                 fprintf(stderr, "COUNTRY environment variable must be an "
 156                         "ISO ISO 3166-1-alpha-2 (uppercase) or 00\n");
 157                 return -EINVAL;
 158         }
 159
 160         memcpy(alpha2, env_country, 2);
 161
 162         fd = open(regdb, O_RDONLY);
 163         if (fd < 0) {
 164                 perror("failed to open db file");
 165                 return -ENOENT;
 166         }
 167
 168         if (fstat(fd, &stat)) {
 169                 perror("failed to fstat db file");
 170                 return -EIO;
 171         }
 172
 173         dblen = stat.st_size;
 174
 175         db = mmap(NULL, dblen, PROT_READ, MAP_PRIVATE, fd, 0);
 176         if (db == MAP_FAILED) {
 177                 perror("failed to mmap db file");
 178                 return -EIO;
 179         }
 180
 181         /* db file starts with a struct regdb_file_header */
 182         header = crda_get_file_ptr(db, dblen, sizeof(*header), 0);
 183
 184         if (ntohl(header->magic) != REGDB_MAGIC) {
 185                 fprintf(stderr, "Invalid database magic\n");
 186                 return -EINVAL;
 187         }
 188
 189         if (ntohl(header->version) != REGDB_VERSION) {
 190                 fprintf(stderr, "Invalid database version\n");
 191                 return -EINVAL;
 192         }
 193
 194         siglen = ntohl(header->signature_length);
 195         /* adjust dblen so later sanity checks don't run into the signature */
 196         dblen -= siglen;
 197
 198         if (dblen <= (int)sizeof(*header)) {
 199                 fprintf(stderr, "Invalid signature length %d\n", siglen);
 200                 return -EINVAL;
 201         }
 202
 203         /* verify signature */
 204         if (!crda_verify_db_signature(db, dblen, siglen))
 205                 return -EINVAL;
 206
 207         num_countries = ntohl(header->reg_country_num);
 208         countries = crda_get_file_ptr(db, dblen,
 209                         sizeof(struct regdb_file_reg_country) * num_countries,
 210                         header->reg_country_ptr);
 211
 212         for (i = 0; i < num_countries; i++) {
 213                 country = countries + i;
 214                 if (memcmp(country->alpha2, alpha2, 2) == 0) {
 215                         found_country = 1;
 216                         break;
 217                 }
 218         }
 219
 220         if (!found_country) {
 221                 fprintf(stderr, "No country match in regulatory database.\n");
 222                 return -1;
 223         }
 224
 225         r = nl80211_init(&nlstate);
 226         if (r)
 227                 return -EIO;
 228
 229         msg = nlmsg_alloc();
 230         if (!msg) {
 231                 fprintf(stderr, "Failed to allocate netlink message.\n");
 232                 r = -1;
 233                 goto out;
 234         }
 235
 236         genlmsg_put(msg, 0, 0, genl_family_get_id(nlstate.nl80211), 0,
 237                 0, NL80211_CMD_SET_REG, 0);
 238
 239         rcoll = crda_get_file_ptr(db, dblen, sizeof(*rcoll),
 240                                 country->reg_collection_ptr);
 241         num_rules = ntohl(rcoll->reg_rule_num);
 242         /* re-get pointer with sanity checking for num_rules */
 243         rcoll = crda_get_file_ptr(db, dblen,
 244                                 sizeof(*rcoll) + num_rules * sizeof(__be32),
 245                                 country->reg_collection_ptr);
 246
 247         NLA_PUT_STRING(msg, NL80211_ATTR_REG_ALPHA2, (char *) country->alpha2);
 248
 249         nl_reg_rules = nla_nest_start(msg, NL80211_ATTR_REG_RULES);
 250         if (!nl_reg_rules) {
 251                 r = -1;
 252                 goto nla_put_failure;
 253         }
 254
 255         for (j = 0; j < num_rules; j++) {
 256                 struct nlattr *nl_reg_rule;
 257                 nl_reg_rule = nla_nest_start(msg, i);
 258                 if (!nl_reg_rule)
 259                         goto nla_put_failure;
 260
 261                 r = put_reg_rule(db, dblen, rcoll->reg_rule_ptrs[j], msg);
 262                 if (r)
 263                         goto nla_put_failure;
 264
 265                 nla_nest_end(msg, nl_reg_rule);
 266         }
 267
 268         nla_nest_end(msg, nl_reg_rules);
 269
 270         cb = nl_cb_alloc(NL_CB_CUSTOM);
 271         if (!cb)
 272                 goto cb_out;
 273
 274         r = nl_send_auto_complete(nlstate.nl_handle, msg);
 275
 276         if (r < 0) {
 277                 fprintf(stderr, "Failed to send regulatory request: %d\n", r);
 278                 goto cb_out;
 279         }
 280
 281         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, reg_handler, NULL);
 282         nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, wait_handler, &finished);
 283         nl_cb_err(cb, NL_CB_CUSTOM, error_handler, NULL);
 284
 285         if (!finished) {
 286                 r = nl_wait_for_ack(nlstate.nl_handle);
 287                 if (r < 0) {
 288                         fprintf(stderr, "Failed to set regulatory domain: "
 289                                 "%d\n", r);
 290                         goto cb_out;
 291                 }
 292         }
 293
 294 cb_out:
 295         nl_cb_put(cb);
 296 nla_put_failure:
 297         nlmsg_free(msg);
 298 out:
 299         nl80211_cleanup(&nlstate);
 300         return r;
 301 }