iw.c

   1 /*
   2  * nl80211 userspace tool
   3  *
   4  * Copyright 2007, 2008 Johannes Berg <johannes@sipsolutions.net>
   5  */
   6
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <net/if.h>
  11 #include <sys/types.h>
  12 #include <sys/stat.h>
  13 #include <fcntl.h>
  14 #include <unistd.h>
  15 #include <stdbool.h>
  16
  17 #include <netlink/genl/genl.h>
  18 #include <netlink/genl/family.h>
  19 #include <netlink/genl/ctrl.h>
  20 #include <netlink/msg.h>
  21 #include <netlink/attr.h>
  22
  23 #include "nl80211.h"
  24 #include "iw.h"
  25
  26 #ifndef CONFIG_LIBNL20
  27 /* libnl 2.0 compatibility code */
  28
  29 static inline struct nl_handle *nl_socket_alloc(void)
  30 {
  31         return nl_handle_alloc();
  32 }
  33
  34 static inline void nl_socket_free(struct nl_sock *h)
  35 {
  36         nl_handle_destroy(h);
  37 }
  38
  39 static inline int __genl_ctrl_alloc_cache(struct nl_sock *h, struct nl_cache **cache)
  40 {
  41         struct nl_cache *tmp = genl_ctrl_alloc_cache(h);
  42         if (!tmp)
  43                 return -ENOMEM;
  44         *cache = tmp;
  45         return 0;
  46 }
  47 #define genl_ctrl_alloc_cache __genl_ctrl_alloc_cache
  48 #endif /* CONFIG_LIBNL20 */
  49
  50 int iw_debug = 0;
  51
  52 static int nl80211_init(struct nl80211_state *state)
  53 {
  54         int err;
  55
  56         state->nl_sock = nl_socket_alloc();
  57         if (!state->nl_sock) {
  58                 fprintf(stderr, "Failed to allocate netlink socket.\n");
  59                 return -ENOMEM;
  60         }
  61
  62         if (genl_connect(state->nl_sock)) {
  63                 fprintf(stderr, "Failed to connect to generic netlink.\n");
  64                 err = -ENOLINK;
  65                 goto out_handle_destroy;
  66         }
  67
  68         if (genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache)) {
  69                 fprintf(stderr, "Failed to allocate generic netlink cache.\n");
  70                 err = -ENOMEM;
  71                 goto out_handle_destroy;
  72         }
  73
  74         state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
  75         if (!state->nl80211) {
  76                 fprintf(stderr, "nl80211 not found.\n");
  77                 err = -ENOENT;
  78                 goto out_cache_free;
  79         }
  80
  81         return 0;
  82
  83  out_cache_free:
  84         nl_cache_free(state->nl_cache);
  85  out_handle_destroy:
  86         nl_socket_free(state->nl_sock);
  87         return err;
  88 }
  89
  90 static void nl80211_cleanup(struct nl80211_state *state)
  91 {
  92         genl_family_put(state->nl80211);
  93         nl_cache_free(state->nl_cache);
  94         nl_socket_free(state->nl_sock);
  95 }
  96
  97 static int cmd_size;
  98
  99 extern struct cmd __start___cmd;
 100 extern struct cmd __stop___cmd;
 101
 102 #define for_each_cmd(_cmd)                                      \
 103         for (_cmd = &__start___cmd; _cmd < &__stop___cmd;               \
 104              _cmd = (const struct cmd *)((char *)_cmd + cmd_size))
 105
 106
 107 static void __usage_cmd(const struct cmd *cmd, char *indent, bool full)
 108 {
 109         const char *start, *lend, *end;
 110
 111         printf("%s", indent);
 112
 113         switch (cmd->idby) {
 114         case CIB_NONE:
 115                 break;
 116         case CIB_PHY:
 117                 printf("phy <phyname> ");
 118                 break;
 119         case CIB_NETDEV:
 120                 printf("dev <devname> ");
 121                 break;
 122         }
 123         if (cmd->parent && cmd->parent->name)
 124                 printf("%s ", cmd->parent->name);
 125         printf("%s", cmd->name);
 126         if (cmd->args)
 127                 printf(" %s", cmd->args);
 128         printf("\n");
 129
 130         if (!full || !cmd->help)
 131                 return;
 132
 133         /* hack */
 134         if (strlen(indent))
 135                 indent = "\t\t";
 136         else
 137                 printf("\n");
 138
 139         /* print line by line */
 140         start = cmd->help;
 141         end = strchr(start, '\0');
 142         do {
 143                 lend = strchr(start, '\n');
 144                 if (!lend)
 145                         lend = end;
 146                 printf("%s", indent);
 147                 printf("%.*s\n", (int)(lend - start), start);
 148                 start = lend + 1;
 149         } while (end != lend);
 150
 151         printf("\n");
 152 }
 153
 154 static void usage_options(void)
 155 {
 156         printf("Options:\n");
 157         printf("\t--debug\t\tenable netlink debugging\n");
 158 }
 159
 160 static const char *argv0;
 161
 162 static void usage(bool full)
 163 {
 164         const struct cmd *section, *cmd;
 165
 166         printf("Usage:\t%s [options] command\n", argv0);
 167         usage_options();
 168         printf("\t--version\tshow version (%s)\n", iw_version);
 169         printf("Commands:\n");
 170         for_each_cmd(section) {
 171                 if (section->parent)
 172                         continue;
 173
 174                 if (section->handler && !section->hidden)
 175                         __usage_cmd(section, "\t", full);
 176
 177                 for_each_cmd(cmd) {
 178                         if (section != cmd->parent)
 179                                 continue;
 180                         if (!cmd->handler || cmd->hidden)
 181                                 continue;
 182                         __usage_cmd(cmd, "\t", full);
 183                 }
 184         }
 185         printf("\nYou can omit the 'phy' or 'dev' if "
 186                         "the identification is unique,\n"
 187                         "e.g. \"iw wlan0 info\" or \"iw phy0 info\". "
 188                         "(Don't when scripting.)\n\n"
 189                         "Do NOT screenscrape this tool, we don't "
 190                         "consider its output stable.\n\n");
 191 }
 192
 193 static int print_help(struct nl80211_state *state,
 194                       struct nl_cb *cb,
 195                       struct nl_msg *msg,
 196                       int argc, char **argv)
 197 {
 198         exit(3);
 199 }
 200 TOPLEVEL(help, NULL, 0, 0, CIB_NONE, print_help,
 201          "Print usage for each command.");
 202
 203 static void usage_cmd(const struct cmd *cmd)
 204 {
 205         printf("Usage:\t%s [options] ", argv0);
 206         __usage_cmd(cmd, "", true);
 207         usage_options();
 208 }
 209
 210 static void version(void)
 211 {
 212         printf("iw version %s\n", iw_version);
 213 }
 214
 215 static int phy_lookup(char *name)
 216 {
 217         char buf[200];
 218         int fd, pos;
 219
 220         snprintf(buf, sizeof(buf), "/sys/class/ieee80211/%s/index", name);
 221
 222         fd = open(buf, O_RDONLY);
 223         if (fd < 0)
 224                 return -1;
 225         pos = read(fd, buf, sizeof(buf) - 1);
 226         if (pos < 0) {
 227                 close(fd);
 228                 return -1;
 229         }
 230         buf[pos] = '\0';
 231         close(fd);
 232         return atoi(buf);
 233 }
 234
 235 static int error_handler(struct sockaddr_nl *nla, struct nlmsgerr *err,
 236                          void *arg)
 237 {
 238         int *ret = arg;
 239         *ret = err->error;
 240         return NL_STOP;
 241 }
 242
 243 static int finish_handler(struct nl_msg *msg, void *arg)
 244 {
 245         int *ret = arg;
 246         *ret = 0;
 247         return NL_SKIP;
 248 }
 249
 250 static int ack_handler(struct nl_msg *msg, void *arg)
 251 {
 252         int *ret = arg;
 253         *ret = 0;
 254         return NL_STOP;
 255 }
 256
 257 static int __handle_cmd(struct nl80211_state *state, enum id_input idby,
 258                         int argc, char **argv, const struct cmd **cmdout)
 259 {
 260         const struct cmd *cmd, *match = NULL, *sectcmd;
 261         struct nl_cb *cb;
 262         struct nl_msg *msg;
 263         int devidx = 0;
 264         int err, o_argc;
 265         const char *command, *section;
 266         char *tmp, **o_argv;
 267         enum command_identify_by command_idby = CIB_NONE;
 268
 269         if (argc <= 1 && idby != II_NONE)
 270                 return 1;
 271
 272         o_argc = argc;
 273         o_argv = argv;
 274
 275         switch (idby) {
 276         case II_PHY_IDX:
 277                 command_idby = CIB_PHY;
 278                 devidx = strtoul(*argv + 4, &tmp, 0);
 279                 if (*tmp != '\0')
 280                         return 1;
 281                 argc--;
 282                 argv++;
 283                 break;
 284         case II_PHY_NAME:
 285                 command_idby = CIB_PHY;
 286                 devidx = phy_lookup(*argv);
 287                 argc--;
 288                 argv++;
 289                 break;
 290         case II_NETDEV:
 291                 command_idby = CIB_NETDEV;
 292                 devidx = if_nametoindex(*argv);
 293                 if (devidx == 0)
 294                         devidx = -1;
 295                 argc--;
 296                 argv++;
 297                 break;
 298         default:
 299                 break;
 300         }
 301
 302         if (devidx < 0)
 303                 return -errno;
 304
 305         section = *argv;
 306         argc--;
 307         argv++;
 308
 309         for_each_cmd(sectcmd) {
 310                 if (sectcmd->parent)
 311                         continue;
 312                 /* ok ... bit of a hack for the dupe 'info' section */
 313                 if (match && sectcmd->idby != command_idby)
 314                         continue;
 315                 if (strcmp(sectcmd->name, section) == 0)
 316                         match = sectcmd;
 317         }
 318
 319         sectcmd = match;
 320         match = NULL;
 321         if (!sectcmd)
 322                 return 1;
 323
 324         if (argc > 0) {
 325                 command = *argv;
 326
 327                 for_each_cmd(cmd) {
 328                         if (!cmd->handler)
 329                                 continue;
 330                         if (cmd->parent != sectcmd)
 331                                 continue;
 332                         if (cmd->idby != command_idby)
 333                                 continue;
 334                         if (strcmp(cmd->name, command))
 335                                 continue;
 336                         if (argc > 1 && !cmd->args)
 337                                 continue;
 338                         match = cmd;
 339                         break;
 340                 }
 341
 342                 if (match) {
 343                         argc--;
 344                         argv++;
 345                 }
 346         }
 347
 348         if (match)
 349                 cmd = match;
 350         else {
 351                 /* Use the section itself, if possible. */
 352                 cmd = sectcmd;
 353                 if (argc && !cmd->args)
 354                         return 1;
 355                 if (cmd->idby != command_idby)
 356                         return 1;
 357                 if (!cmd->handler)
 358                         return 1;
 359         }
 360
 361         if (cmdout)
 362                 *cmdout = cmd;
 363
 364         if (!cmd->cmd) {
 365                 argc = o_argc;
 366                 argv = o_argv;
 367                 return cmd->handler(state, NULL, NULL, argc, argv);
 368         }
 369
 370         msg = nlmsg_alloc();
 371         if (!msg) {
 372                 fprintf(stderr, "failed to allocate netlink message\n");
 373                 return 2;
 374         }
 375
 376         cb = nl_cb_alloc(iw_debug ? NL_CB_DEBUG : NL_CB_DEFAULT);
 377         if (!cb) {
 378                 fprintf(stderr, "failed to allocate netlink callbacks\n");
 379                 err = 2;
 380                 goto out_free_msg;
 381         }
 382
 383         genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
 384                     cmd->nl_msg_flags, cmd->cmd, 0);
 385
 386         switch (command_idby) {
 387         case CIB_PHY:
 388                 NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, devidx);
 389                 break;
 390         case CIB_NETDEV:
 391                 NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, devidx);
 392                 break;
 393         default:
 394                 break;
 395         }
 396
 397         err = cmd->handler(state, cb, msg, argc, argv);
 398         if (err)
 399                 goto out;
 400
 401         err = nl_send_auto_complete(state->nl_sock, msg);
 402         if (err < 0)
 403                 goto out;
 404
 405         err = 1;
 406
 407         nl_cb_err(cb, NL_CB_CUSTOM, error_handler, &err);
 408         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, finish_handler, &err);
 409         nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_handler, &err);
 410
 411         while (err > 0)
 412                 nl_recvmsgs(state->nl_sock, cb);
 413  out:
 414         nl_cb_put(cb);
 415  out_free_msg:
 416         nlmsg_free(msg);
 417         return err;
 418  nla_put_failure:
 419         fprintf(stderr, "building message failed\n");
 420         return 2;
 421 }
 422
 423 int handle_cmd(struct nl80211_state *state, enum id_input idby,
 424                int argc, char **argv)
 425 {
 426         return __handle_cmd(state, idby, argc, argv, NULL);
 427 }
 428
 429 int main(int argc, char **argv)
 430 {
 431         struct nl80211_state nlstate;
 432         int err;
 433         const struct cmd *cmd = NULL;
 434
 435         /* calculate command size including padding */
 436         cmd_size = abs((long)&__section_set - (long)&__section_get);
 437         /* strip off self */
 438         argc--;
 439         argv0 = *argv++;
 440
 441         if (argc > 0 && strcmp(*argv, "--debug") == 0) {
 442                 iw_debug = 1;
 443                 argc--;
 444                 argv++;
 445         }
 446
 447         if (argc > 0 && strcmp(*argv, "--version") == 0) {
 448                 version();
 449                 return 0;
 450         }
 451
 452         /* need to treat "help" command specially so it works w/o nl80211 */
 453         if (argc == 0 || strcmp(*argv, "help") == 0) {
 454                 usage(argc != 0);
 455                 return 0;
 456         }
 457
 458         err = nl80211_init(&nlstate);
 459         if (err)
 460                 return 1;
 461
 462         if (strcmp(*argv, "dev") == 0 && argc > 1) {
 463                 argc--;
 464                 argv++;
 465                 err = __handle_cmd(&nlstate, II_NETDEV, argc, argv, &cmd);
 466         } else if (strncmp(*argv, "phy", 3) == 0 && argc > 1) {
 467                 if (strlen(*argv) == 3) {
 468                         argc--;
 469                         argv++;
 470                         err = __handle_cmd(&nlstate, II_PHY_NAME, argc, argv, &cmd);
 471                 } else if (*(*argv + 3) == '#')
 472                         err = __handle_cmd(&nlstate, II_PHY_IDX, argc, argv, &cmd);
 473                 else
 474                         goto detect;
 475         } else {
 476                 int idx;
 477                 enum id_input idby = II_NONE;
 478  detect:
 479                 if ((idx = if_nametoindex(argv[0])) != 0)
 480                         idby = II_NETDEV;
 481                 else if ((idx = phy_lookup(argv[0])) >= 0)
 482                         idby = II_PHY_NAME;
 483                 err = __handle_cmd(&nlstate, idby, argc, argv, &cmd);
 484         }
 485
 486         if (err == 1) {
 487                 if (cmd)
 488                         usage_cmd(cmd);
 489                 else
 490                         usage(false);
 491         } else if (err < 0)
 492                 fprintf(stderr, "command failed: %s (%d)\n", strerror(-err), err);
 493
 494         nl80211_cleanup(&nlstate);
 495
 496         return err;
 497 }