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 "nl80211.h"
  20
  21 #include "regdb.h"
  22 #include "reglib.h"
  23
  24 #ifndef CONFIG_LIBNL20
  25 /* libnl 2.0 compatibility code */
  26 static inline struct nl_handle *nl_socket_alloc(void)
  27 {
  28        return nl_handle_alloc();
  29 }
  30
  31 static inline void nl_socket_free(struct nl_handle *h)
  32 {
  33        nl_handle_destroy(h);
  34 }
  35
  36 static inline int __genl_ctrl_alloc_cache(struct nl_handle *h, struct nl_cache **cache)
  37 {
  38        struct nl_cache *tmp = genl_ctrl_alloc_cache(h);
  39        if (!tmp)
  40                return -ENOMEM;
  41        *cache = tmp;
  42        return 0;
  43 }
  44
  45 #define genl_ctrl_alloc_cache __genl_ctrl_alloc_cache
  46 #endif /* CONFIG_LIBNL20 */
  47
  48 struct nl80211_state {
  49         struct nl_handle *nl_handle;
  50         struct nl_cache *nl_cache;
  51         struct genl_family *nl80211;
  52 };
  53
  54 static int nl80211_init(struct nl80211_state *state)
  55 {
  56         int err;
  57
  58         state->nl_handle = nl_socket_alloc();
  59         if (!state->nl_handle) {
  60                 fprintf(stderr, "Failed to allocate netlink handle.\n");
  61                 return -ENOMEM;
  62         }
  63
  64         if (genl_connect(state->nl_handle)) {
  65                 fprintf(stderr, "Failed to connect to generic netlink.\n");
  66                 err = -ENOLINK;
  67                 goto out_handle_destroy;
  68         }
  69
  70         if (genl_ctrl_alloc_cache(state->nl_handle, &state->nl_cache)) {
  71                 fprintf(stderr, "Failed to allocate generic netlink cache.\n");
  72                 err = -ENOMEM;
  73                 goto out_handle_destroy;
  74         }
  75
  76         state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
  77         if (!state->nl80211) {
  78                 fprintf(stderr, "nl80211 not found.\n");
  79                 err = -ENOENT;
  80                 goto out_cache_free;
  81         }
  82
  83         return 0;
  84
  85  out_cache_free:
  86         nl_cache_free(state->nl_cache);
  87  out_handle_destroy:
  88         nl_socket_free(state->nl_handle);
  89         return err;
  90 }
  91
  92 static void nl80211_cleanup(struct nl80211_state *state)
  93 {
  94         genl_family_put(state->nl80211);
  95         nl_cache_free(state->nl_cache);
  96         nl_socket_free(state->nl_handle);
  97 }
  98
  99 static int reg_handler(struct nl_msg __attribute__((unused)) *msg,
 100                         void __attribute__((unused)) *arg)
 101 {
 102         return NL_SKIP;
 103 }
 104
 105 static int wait_handler(struct nl_msg __attribute__((unused)) *msg, void *arg)
 106 {
 107         int *finished = arg;
 108         *finished = 1;
 109         return NL_STOP;
 110 }
 111
 112 static int error_handler(struct sockaddr_nl __attribute__((unused)) *nla,
 113                             struct nlmsgerr *err,
 114                             void __attribute__((unused)) *arg)
 115 {
 116         fprintf(stderr, "nl80211 error %d\n", err->error);
 117         exit(err->error);
 118 }
 119
 120 static int put_reg_rule(__u8 *db, int dblen, __be32 ruleptr, struct nl_msg *msg)
 121 {
 122         struct regdb_file_reg_rule *rule;
 123         struct regdb_file_freq_range *freq;
 124         struct regdb_file_power_rule *power;
 125
 126         rule  = crda_get_file_ptr(db, dblen, sizeof(*rule), ruleptr);
 127         freq  = crda_get_file_ptr(db, dblen, sizeof(*freq), rule->freq_range_ptr);
 128         power = crda_get_file_ptr(db, dblen, sizeof(*power), rule->power_rule_ptr);
 129
 130         NLA_PUT_U32(msg, NL80211_ATTR_REG_RULE_FLAGS,           ntohl(rule->flags));
 131         NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_START,         ntohl(freq->start_freq));
 132         NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_END,           ntohl(freq->end_freq));
 133         NLA_PUT_U32(msg, NL80211_ATTR_FREQ_RANGE_MAX_BW,        ntohl(freq->max_bandwidth));
 134         NLA_PUT_U32(msg, NL80211_ATTR_POWER_RULE_MAX_ANT_GAIN,  ntohl(power->max_antenna_gain));
 135         NLA_PUT_U32(msg, NL80211_ATTR_POWER_RULE_MAX_EIRP,      ntohl(power->max_eirp));
 136
 137         return 0;
 138
 139 nla_put_failure:
 140         return -1;
 141 }
 142
 143 int main(int argc, char **argv)
 144 {
 145         int fd;
 146         struct stat stat;
 147         __u8 *db;
 148         struct regdb_file_header *header;
 149         struct regdb_file_reg_country *countries;
 150         int dblen, siglen, num_countries, i, j, r;
 151         char alpha2[2];
 152         char *env_country;
 153         struct nl80211_state nlstate;
 154         struct nl_cb *cb = NULL;
 155         struct nl_msg *msg;
 156         int found_country = 0;
 157         int finished = 0;
 158
 159         struct regdb_file_reg_rules_collection *rcoll;
 160         struct regdb_file_reg_country *country;
 161         struct nlattr *nl_reg_rules;
 162         int num_rules;
 163
 164         const char regdb[] = "/usr/lib/crda/regulatory.bin";
 165
 166         if (argc != 1) {
 167                 fprintf(stderr, "Usage: %s\n", argv[0]);
 168                 return -EINVAL;
 169         }
 170
 171         env_country = getenv("COUNTRY");
 172         if (!env_country) {
 173                 fprintf(stderr, "COUNTRY environment variable not set.\n");
 174                 return -EINVAL;
 175         }
 176
 177         if (!is_valid_regdom(env_country)) {
 178                 fprintf(stderr, "COUNTRY environment variable must be an "
 179                         "ISO ISO 3166-1-alpha-2 (uppercase) or 00\n");
 180                 return -EINVAL;
 181         }
 182
 183         memcpy(alpha2, env_country, 2);
 184
 185         fd = open(regdb, O_RDONLY);
 186         if (fd < 0) {
 187                 perror("failed to open db file");
 188                 return -ENOENT;
 189         }
 190
 191         if (fstat(fd, &stat)) {
 192                 perror("failed to fstat db file");
 193                 return -EIO;
 194         }
 195
 196         dblen = stat.st_size;
 197
 198         db = mmap(NULL, dblen, PROT_READ, MAP_PRIVATE, fd, 0);
 199         if (db == MAP_FAILED) {
 200                 perror("failed to mmap db file");
 201                 return -EIO;
 202         }
 203
 204         /* db file starts with a struct regdb_file_header */
 205         header = crda_get_file_ptr(db, dblen, sizeof(*header), 0);
 206
 207         if (ntohl(header->magic) != REGDB_MAGIC) {
 208                 fprintf(stderr, "Invalid database magic\n");
 209                 return -EINVAL;
 210         }
 211
 212         if (ntohl(header->version) != REGDB_VERSION) {
 213                 fprintf(stderr, "Invalid database version\n");
 214                 return -EINVAL;
 215         }
 216
 217         siglen = ntohl(header->signature_length);
 218         /* adjust dblen so later sanity checks don't run into the signature */
 219         dblen -= siglen;
 220
 221         if (dblen <= (int)sizeof(*header)) {
 222                 fprintf(stderr, "Invalid signature length %d\n", siglen);
 223                 return -EINVAL;
 224         }
 225
 226         /* verify signature */
 227         if (!crda_verify_db_signature(db, dblen, siglen))
 228                 return -EINVAL;
 229
 230         num_countries = ntohl(header->reg_country_num);
 231         countries = crda_get_file_ptr(db, dblen,
 232                         sizeof(struct regdb_file_reg_country) * num_countries,
 233                         header->reg_country_ptr);
 234
 235         for (i = 0; i < num_countries; i++) {
 236                 country = countries + i;
 237                 if (memcmp(country->alpha2, alpha2, 2) == 0) {
 238                         found_country = 1;
 239                         break;
 240                 }
 241         }
 242
 243         if (!found_country) {
 244                 fprintf(stderr, "No country match in regulatory database.\n");
 245                 return -1;
 246         }
 247
 248         r = nl80211_init(&nlstate);
 249         if (r)
 250                 return -EIO;
 251
 252         msg = nlmsg_alloc();
 253         if (!msg) {
 254                 fprintf(stderr, "Failed to allocate netlink message.\n");
 255                 r = -1;
 256                 goto out;
 257         }
 258
 259         genlmsg_put(msg, 0, 0, genl_family_get_id(nlstate.nl80211), 0,
 260                 0, NL80211_CMD_SET_REG, 0);
 261
 262         rcoll = crda_get_file_ptr(db, dblen, sizeof(*rcoll),
 263                                 country->reg_collection_ptr);
 264         num_rules = ntohl(rcoll->reg_rule_num);
 265         /* re-get pointer with sanity checking for num_rules */
 266         rcoll = crda_get_file_ptr(db, dblen,
 267                                 sizeof(*rcoll) + num_rules * sizeof(__be32),
 268                                 country->reg_collection_ptr);
 269
 270         NLA_PUT_STRING(msg, NL80211_ATTR_REG_ALPHA2, (char *) country->alpha2);
 271
 272         nl_reg_rules = nla_nest_start(msg, NL80211_ATTR_REG_RULES);
 273         if (!nl_reg_rules) {
 274                 r = -1;
 275                 goto nla_put_failure;
 276         }
 277
 278         for (j = 0; j < num_rules; j++) {
 279                 struct nlattr *nl_reg_rule;
 280                 nl_reg_rule = nla_nest_start(msg, i);
 281                 if (!nl_reg_rule)
 282                         goto nla_put_failure;
 283
 284                 r = put_reg_rule(db, dblen, rcoll->reg_rule_ptrs[j], msg);
 285                 if (r)
 286                         goto nla_put_failure;
 287
 288                 nla_nest_end(msg, nl_reg_rule);
 289         }
 290
 291         nla_nest_end(msg, nl_reg_rules);
 292
 293         cb = nl_cb_alloc(NL_CB_CUSTOM);
 294         if (!cb)
 295                 goto cb_out;
 296
 297         r = nl_send_auto_complete(nlstate.nl_handle, msg);
 298
 299         if (r < 0) {
 300                 fprintf(stderr, "Failed to send regulatory request: %d\n", r);
 301                 goto cb_out;
 302         }
 303
 304         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, reg_handler, NULL);
 305         nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, wait_handler, &finished);
 306         nl_cb_err(cb, NL_CB_CUSTOM, error_handler, NULL);
 307
 308         if (!finished) {
 309                 r = nl_wait_for_ack(nlstate.nl_handle);
 310                 if (r < 0) {
 311                         fprintf(stderr, "Failed to set regulatory domain: "
 312                                 "%d\n", r);
 313                         goto cb_out;
 314                 }
 315         }
 316
 317 cb_out:
 318         nl_cb_put(cb);
 319 nla_put_failure:
 320         nlmsg_free(msg);
 321 out:
 322         nl80211_cleanup(&nlstate);
 323         return r;
 324 }