net/batman-adv/hard-interface.c

   1 /* Copyright (C) 2007-2012 B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner, Simon Wunderlich
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include "hard-interface.h"
  22 #include "soft-interface.h"
  23 #include "send.h"
  24 #include "translation-table.h"
  25 #include "routing.h"
  26 #include "bat_sysfs.h"
  27 #include "originator.h"
  28 #include "hash.h"
  29 #include "bridge_loop_avoidance.h"
  30
  31 #include <linux/if_arp.h>
  32
  33 void batadv_hardif_free_rcu(struct rcu_head *rcu)
  34 {
  35         struct hard_iface *hard_iface;
  36
  37         hard_iface = container_of(rcu, struct hard_iface, rcu);
  38         dev_put(hard_iface->net_dev);
  39         kfree(hard_iface);
  40 }
  41
  42 struct hard_iface *batadv_hardif_get_by_netdev(const struct net_device *net_dev)
  43 {
  44         struct hard_iface *hard_iface;
  45
  46         rcu_read_lock();
  47         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
  48                 if (hard_iface->net_dev == net_dev &&
  49                     atomic_inc_not_zero(&hard_iface->refcount))
  50                         goto out;
  51         }
  52
  53         hard_iface = NULL;
  54
  55 out:
  56         rcu_read_unlock();
  57         return hard_iface;
  58 }
  59
  60 static int batadv_is_valid_iface(const struct net_device *net_dev)
  61 {
  62         if (net_dev->flags & IFF_LOOPBACK)
  63                 return 0;
  64
  65         if (net_dev->type != ARPHRD_ETHER)
  66                 return 0;
  67
  68         if (net_dev->addr_len != ETH_ALEN)
  69                 return 0;
  70
  71         /* no batman over batman */
  72         if (batadv_softif_is_valid(net_dev))
  73                 return 0;
  74
  75         return 1;
  76 }
  77
  78 static struct hard_iface *
  79 batadv_hardif_get_active(const struct net_device *soft_iface)
  80 {
  81         struct hard_iface *hard_iface;
  82
  83         rcu_read_lock();
  84         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
  85                 if (hard_iface->soft_iface != soft_iface)
  86                         continue;
  87
  88                 if (hard_iface->if_status == BATADV_IF_ACTIVE &&
  89                     atomic_inc_not_zero(&hard_iface->refcount))
  90                         goto out;
  91         }
  92
  93         hard_iface = NULL;
  94
  95 out:
  96         rcu_read_unlock();
  97         return hard_iface;
  98 }
  99
 100 static void batadv_primary_if_update_addr(struct bat_priv *bat_priv,
 101                                           struct hard_iface *oldif)
 102 {
 103         struct batadv_vis_packet *vis_packet;
 104         struct hard_iface *primary_if;
 105
 106         primary_if = batadv_primary_if_get_selected(bat_priv);
 107         if (!primary_if)
 108                 goto out;
 109
 110         vis_packet = (struct batadv_vis_packet *)
 111                                 bat_priv->my_vis_info->skb_packet->data;
 112         memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 113         memcpy(vis_packet->sender_orig,
 114                primary_if->net_dev->dev_addr, ETH_ALEN);
 115
 116         batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
 117 out:
 118         if (primary_if)
 119                 batadv_hardif_free_ref(primary_if);
 120 }
 121
 122 static void batadv_primary_if_select(struct bat_priv *bat_priv,
 123                                      struct hard_iface *new_hard_iface)
 124 {
 125         struct hard_iface *curr_hard_iface;
 126
 127         ASSERT_RTNL();
 128
 129         if (new_hard_iface && !atomic_inc_not_zero(&new_hard_iface->refcount))
 130                 new_hard_iface = NULL;
 131
 132         curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
 133         rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
 134
 135         if (!new_hard_iface)
 136                 goto out;
 137
 138         bat_priv->bat_algo_ops->bat_primary_iface_set(new_hard_iface);
 139         batadv_primary_if_update_addr(bat_priv, curr_hard_iface);
 140
 141 out:
 142         if (curr_hard_iface)
 143                 batadv_hardif_free_ref(curr_hard_iface);
 144 }
 145
 146 static bool batadv_hardif_is_iface_up(const struct hard_iface *hard_iface)
 147 {
 148         if (hard_iface->net_dev->flags & IFF_UP)
 149                 return true;
 150
 151         return false;
 152 }
 153
 154 static void batadv_check_known_mac_addr(const struct net_device *net_dev)
 155 {
 156         const struct hard_iface *hard_iface;
 157
 158         rcu_read_lock();
 159         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 160                 if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 161                     (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 162                         continue;
 163
 164                 if (hard_iface->net_dev == net_dev)
 165                         continue;
 166
 167                 if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
 168                                         net_dev->dev_addr))
 169                         continue;
 170
 171                 pr_warn("The newly added mac address (%pM) already exists on: %s\n",
 172                         net_dev->dev_addr, hard_iface->net_dev->name);
 173                 pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
 174         }
 175         rcu_read_unlock();
 176 }
 177
 178 int batadv_hardif_min_mtu(struct net_device *soft_iface)
 179 {
 180         const struct bat_priv *bat_priv = netdev_priv(soft_iface);
 181         const struct hard_iface *hard_iface;
 182         /* allow big frames if all devices are capable to do so
 183          * (have MTU > 1500 + BAT_HEADER_LEN)
 184          */
 185         int min_mtu = ETH_DATA_LEN;
 186
 187         if (atomic_read(&bat_priv->fragmentation))
 188                 goto out;
 189
 190         rcu_read_lock();
 191         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 192                 if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 193                     (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 194                         continue;
 195
 196                 if (hard_iface->soft_iface != soft_iface)
 197                         continue;
 198
 199                 min_mtu = min_t(int,
 200                                 hard_iface->net_dev->mtu - BATADV_HEADER_LEN,
 201                                 min_mtu);
 202         }
 203         rcu_read_unlock();
 204 out:
 205         return min_mtu;
 206 }
 207
 208 /* adjusts the MTU if a new interface with a smaller MTU appeared. */
 209 void batadv_update_min_mtu(struct net_device *soft_iface)
 210 {
 211         int min_mtu;
 212
 213         min_mtu = batadv_hardif_min_mtu(soft_iface);
 214         if (soft_iface->mtu != min_mtu)
 215                 soft_iface->mtu = min_mtu;
 216 }
 217
 218 static void batadv_hardif_activate_interface(struct hard_iface *hard_iface)
 219 {
 220         struct bat_priv *bat_priv;
 221         struct hard_iface *primary_if = NULL;
 222
 223         if (hard_iface->if_status != BATADV_IF_INACTIVE)
 224                 goto out;
 225
 226         bat_priv = netdev_priv(hard_iface->soft_iface);
 227
 228         bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
 229         hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;
 230
 231         /* the first active interface becomes our primary interface or
 232          * the next active interface after the old primary interface was removed
 233          */
 234         primary_if = batadv_primary_if_get_selected(bat_priv);
 235         if (!primary_if)
 236                 batadv_primary_if_select(bat_priv, hard_iface);
 237
 238         batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
 239                     hard_iface->net_dev->name);
 240
 241         batadv_update_min_mtu(hard_iface->soft_iface);
 242
 243 out:
 244         if (primary_if)
 245                 batadv_hardif_free_ref(primary_if);
 246 }
 247
 248 static void batadv_hardif_deactivate_interface(struct hard_iface *hard_iface)
 249 {
 250         if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 251             (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 252                 return;
 253
 254         hard_iface->if_status = BATADV_IF_INACTIVE;
 255
 256         batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
 257                     hard_iface->net_dev->name);
 258
 259         batadv_update_min_mtu(hard_iface->soft_iface);
 260 }
 261
 262 int batadv_hardif_enable_interface(struct hard_iface *hard_iface,
 263                                    const char *iface_name)
 264 {
 265         struct bat_priv *bat_priv;
 266         struct net_device *soft_iface;
 267         __be16 ethertype = __constant_htons(BATADV_ETH_P_BATMAN);
 268         int ret;
 269
 270         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 271                 goto out;
 272
 273         if (!atomic_inc_not_zero(&hard_iface->refcount))
 274                 goto out;
 275
 276         /* hard-interface is part of a bridge */
 277         if (hard_iface->net_dev->priv_flags & IFF_BRIDGE_PORT)
 278                 pr_err("You are about to enable batman-adv on '%s' which already is part of a bridge. Unless you know exactly what you are doing this is probably wrong and won't work the way you think it would.\n",
 279                        hard_iface->net_dev->name);
 280
 281         soft_iface = dev_get_by_name(&init_net, iface_name);
 282
 283         if (!soft_iface) {
 284                 soft_iface = batadv_softif_create(iface_name);
 285
 286                 if (!soft_iface) {
 287                         ret = -ENOMEM;
 288                         goto err;
 289                 }
 290
 291                 /* dev_get_by_name() increases the reference counter for us */
 292                 dev_hold(soft_iface);
 293         }
 294
 295         if (!batadv_softif_is_valid(soft_iface)) {
 296                 pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
 297                        soft_iface->name);
 298                 ret = -EINVAL;
 299                 goto err_dev;
 300         }
 301
 302         hard_iface->soft_iface = soft_iface;
 303         bat_priv = netdev_priv(hard_iface->soft_iface);
 304
 305         ret = bat_priv->bat_algo_ops->bat_iface_enable(hard_iface);
 306         if (ret < 0)
 307                 goto err_dev;
 308
 309         hard_iface->if_num = bat_priv->num_ifaces;
 310         bat_priv->num_ifaces++;
 311         hard_iface->if_status = BATADV_IF_INACTIVE;
 312         batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
 313
 314         hard_iface->batman_adv_ptype.type = ethertype;
 315         hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
 316         hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
 317         dev_add_pack(&hard_iface->batman_adv_ptype);
 318
 319         atomic_set(&hard_iface->frag_seqno, 1);
 320         batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
 321                     hard_iface->net_dev->name);
 322
 323         if (atomic_read(&bat_priv->fragmentation) && hard_iface->net_dev->mtu <
 324                 ETH_DATA_LEN + BATADV_HEADER_LEN)
 325                 batadv_info(hard_iface->soft_iface,
 326                             "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to %zi would solve the problem.\n",
 327                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 328                             ETH_DATA_LEN + BATADV_HEADER_LEN);
 329
 330         if (!atomic_read(&bat_priv->fragmentation) && hard_iface->net_dev->mtu <
 331                 ETH_DATA_LEN + BATADV_HEADER_LEN)
 332                 batadv_info(hard_iface->soft_iface,
 333                             "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. If you experience problems getting traffic through try increasing the MTU to %zi.\n",
 334                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 335                             ETH_DATA_LEN + BATADV_HEADER_LEN);
 336
 337         if (batadv_hardif_is_iface_up(hard_iface))
 338                 batadv_hardif_activate_interface(hard_iface);
 339         else
 340                 batadv_err(hard_iface->soft_iface,
 341                            "Not using interface %s (retrying later): interface not active\n",
 342                            hard_iface->net_dev->name);
 343
 344         /* begin scheduling originator messages on that interface */
 345         batadv_schedule_bat_ogm(hard_iface);
 346
 347 out:
 348         return 0;
 349
 350 err_dev:
 351         dev_put(soft_iface);
 352 err:
 353         batadv_hardif_free_ref(hard_iface);
 354         return ret;
 355 }
 356
 357 void batadv_hardif_disable_interface(struct hard_iface *hard_iface)
 358 {
 359         struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 360         struct hard_iface *primary_if = NULL;
 361
 362         if (hard_iface->if_status == BATADV_IF_ACTIVE)
 363                 batadv_hardif_deactivate_interface(hard_iface);
 364
 365         if (hard_iface->if_status != BATADV_IF_INACTIVE)
 366                 goto out;
 367
 368         batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
 369                     hard_iface->net_dev->name);
 370         dev_remove_pack(&hard_iface->batman_adv_ptype);
 371
 372         bat_priv->num_ifaces--;
 373         batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
 374
 375         primary_if = batadv_primary_if_get_selected(bat_priv);
 376         if (hard_iface == primary_if) {
 377                 struct hard_iface *new_if;
 378
 379                 new_if = batadv_hardif_get_active(hard_iface->soft_iface);
 380                 batadv_primary_if_select(bat_priv, new_if);
 381
 382                 if (new_if)
 383                         batadv_hardif_free_ref(new_if);
 384         }
 385
 386         bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
 387         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 388
 389         /* delete all references to this hard_iface */
 390         batadv_purge_orig_ref(bat_priv);
 391         batadv_purge_outstanding_packets(bat_priv, hard_iface);
 392         dev_put(hard_iface->soft_iface);
 393
 394         /* nobody uses this interface anymore */
 395         if (!bat_priv->num_ifaces)
 396                 batadv_softif_destroy(hard_iface->soft_iface);
 397
 398         hard_iface->soft_iface = NULL;
 399         batadv_hardif_free_ref(hard_iface);
 400
 401 out:
 402         if (primary_if)
 403                 batadv_hardif_free_ref(primary_if);
 404 }
 405
 406 static struct hard_iface *
 407 batadv_hardif_add_interface(struct net_device *net_dev)
 408 {
 409         struct hard_iface *hard_iface;
 410         int ret;
 411
 412         ASSERT_RTNL();
 413
 414         ret = batadv_is_valid_iface(net_dev);
 415         if (ret != 1)
 416                 goto out;
 417
 418         dev_hold(net_dev);
 419
 420         hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
 421         if (!hard_iface)
 422                 goto release_dev;
 423
 424         ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
 425         if (ret)
 426                 goto free_if;
 427
 428         hard_iface->if_num = -1;
 429         hard_iface->net_dev = net_dev;
 430         hard_iface->soft_iface = NULL;
 431         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 432         INIT_LIST_HEAD(&hard_iface->list);
 433         /* extra reference for return */
 434         atomic_set(&hard_iface->refcount, 2);
 435
 436         batadv_check_known_mac_addr(hard_iface->net_dev);
 437         list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
 438
 439         /* This can't be called via a bat_priv callback because
 440          * we have no bat_priv yet.
 441          */
 442         atomic_set(&hard_iface->seqno, 1);
 443         hard_iface->packet_buff = NULL;
 444
 445         return hard_iface;
 446
 447 free_if:
 448         kfree(hard_iface);
 449 release_dev:
 450         dev_put(net_dev);
 451 out:
 452         return NULL;
 453 }
 454
 455 static void batadv_hardif_remove_interface(struct hard_iface *hard_iface)
 456 {
 457         ASSERT_RTNL();
 458
 459         /* first deactivate interface */
 460         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 461                 batadv_hardif_disable_interface(hard_iface);
 462
 463         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 464                 return;
 465
 466         hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
 467         batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
 468         batadv_hardif_free_ref(hard_iface);
 469 }
 470
 471 void batadv_hardif_remove_interfaces(void)
 472 {
 473         struct hard_iface *hard_iface, *hard_iface_tmp;
 474
 475         rtnl_lock();
 476         list_for_each_entry_safe(hard_iface, hard_iface_tmp,
 477                                  &batadv_hardif_list, list) {
 478                 list_del_rcu(&hard_iface->list);
 479                 batadv_hardif_remove_interface(hard_iface);
 480         }
 481         rtnl_unlock();
 482 }
 483
 484 static int batadv_hard_if_event(struct notifier_block *this,
 485                                 unsigned long event, void *ptr)
 486 {
 487         struct net_device *net_dev = ptr;
 488         struct hard_iface *hard_iface = batadv_hardif_get_by_netdev(net_dev);
 489         struct hard_iface *primary_if = NULL;
 490         struct bat_priv *bat_priv;
 491
 492         if (!hard_iface && event == NETDEV_REGISTER)
 493                 hard_iface = batadv_hardif_add_interface(net_dev);
 494
 495         if (!hard_iface)
 496                 goto out;
 497
 498         switch (event) {
 499         case NETDEV_UP:
 500                 batadv_hardif_activate_interface(hard_iface);
 501                 break;
 502         case NETDEV_GOING_DOWN:
 503         case NETDEV_DOWN:
 504                 batadv_hardif_deactivate_interface(hard_iface);
 505                 break;
 506         case NETDEV_UNREGISTER:
 507                 list_del_rcu(&hard_iface->list);
 508
 509                 batadv_hardif_remove_interface(hard_iface);
 510                 break;
 511         case NETDEV_CHANGEMTU:
 512                 if (hard_iface->soft_iface)
 513                         batadv_update_min_mtu(hard_iface->soft_iface);
 514                 break;
 515         case NETDEV_CHANGEADDR:
 516                 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
 517                         goto hardif_put;
 518
 519                 batadv_check_known_mac_addr(hard_iface->net_dev);
 520
 521                 bat_priv = netdev_priv(hard_iface->soft_iface);
 522                 bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
 523
 524                 primary_if = batadv_primary_if_get_selected(bat_priv);
 525                 if (!primary_if)
 526                         goto hardif_put;
 527
 528                 if (hard_iface == primary_if)
 529                         batadv_primary_if_update_addr(bat_priv, NULL);
 530                 break;
 531         default:
 532                 break;
 533         }
 534
 535 hardif_put:
 536         batadv_hardif_free_ref(hard_iface);
 537 out:
 538         if (primary_if)
 539                 batadv_hardif_free_ref(primary_if);
 540         return NOTIFY_DONE;
 541 }
 542
 543 /* This function returns true if the interface represented by ifindex is a
 544  * 802.11 wireless device
 545  */
 546 bool batadv_is_wifi_iface(int ifindex)
 547 {
 548         struct net_device *net_device = NULL;
 549         bool ret = false;
 550
 551         if (ifindex == BATADV_NULL_IFINDEX)
 552                 goto out;
 553
 554         net_device = dev_get_by_index(&init_net, ifindex);
 555         if (!net_device)
 556                 goto out;
 557
 558 #ifdef CONFIG_WIRELESS_EXT
 559         /* pre-cfg80211 drivers have to implement WEXT, so it is possible to
 560          * check for wireless_handlers != NULL
 561          */
 562         if (net_device->wireless_handlers)
 563                 ret = true;
 564         else
 565 #endif
 566                 /* cfg80211 drivers have to set ieee80211_ptr */
 567                 if (net_device->ieee80211_ptr)
 568                         ret = true;
 569 out:
 570         if (net_device)
 571                 dev_put(net_device);
 572         return ret;
 573 }
 574
 575 struct notifier_block batadv_hard_if_notifier = {
 576         .notifier_call = batadv_hard_if_event,
 577 };