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 "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 batadv_hard_iface *hard_iface;
  36
  37         hard_iface = container_of(rcu, struct batadv_hard_iface, rcu);
  38         dev_put(hard_iface->net_dev);
  39         kfree(hard_iface);
  40 }
  41
  42 struct batadv_hard_iface *
  43 batadv_hardif_get_by_netdev(const struct net_device *net_dev)
  44 {
  45         struct batadv_hard_iface *hard_iface;
  46
  47         rcu_read_lock();
  48         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
  49                 if (hard_iface->net_dev == net_dev &&
  50                     atomic_inc_not_zero(&hard_iface->refcount))
  51                         goto out;
  52         }
  53
  54         hard_iface = NULL;
  55
  56 out:
  57         rcu_read_unlock();
  58         return hard_iface;
  59 }
  60
  61 static int batadv_is_valid_iface(const struct net_device *net_dev)
  62 {
  63         if (net_dev->flags & IFF_LOOPBACK)
  64                 return 0;
  65
  66         if (net_dev->type != ARPHRD_ETHER)
  67                 return 0;
  68
  69         if (net_dev->addr_len != ETH_ALEN)
  70                 return 0;
  71
  72         /* no batman over batman */
  73         if (batadv_softif_is_valid(net_dev))
  74                 return 0;
  75
  76         return 1;
  77 }
  78
  79 static struct batadv_hard_iface *
  80 batadv_hardif_get_active(const struct net_device *soft_iface)
  81 {
  82         struct batadv_hard_iface *hard_iface;
  83
  84         rcu_read_lock();
  85         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
  86                 if (hard_iface->soft_iface != soft_iface)
  87                         continue;
  88
  89                 if (hard_iface->if_status == BATADV_IF_ACTIVE &&
  90                     atomic_inc_not_zero(&hard_iface->refcount))
  91                         goto out;
  92         }
  93
  94         hard_iface = NULL;
  95
  96 out:
  97         rcu_read_unlock();
  98         return hard_iface;
  99 }
 100
 101 static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
 102                                           struct batadv_hard_iface *oldif)
 103 {
 104         struct batadv_vis_packet *vis_packet;
 105         struct batadv_hard_iface *primary_if;
 106
 107         primary_if = batadv_primary_if_get_selected(bat_priv);
 108         if (!primary_if)
 109                 goto out;
 110
 111         vis_packet = (struct batadv_vis_packet *)
 112                                 bat_priv->my_vis_info->skb_packet->data;
 113         memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 114         memcpy(vis_packet->sender_orig,
 115                primary_if->net_dev->dev_addr, ETH_ALEN);
 116
 117         batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
 118 out:
 119         if (primary_if)
 120                 batadv_hardif_free_ref(primary_if);
 121 }
 122
 123 static void batadv_primary_if_select(struct batadv_priv *bat_priv,
 124                                      struct batadv_hard_iface *new_hard_iface)
 125 {
 126         struct batadv_hard_iface *curr_hard_iface;
 127
 128         ASSERT_RTNL();
 129
 130         if (new_hard_iface && !atomic_inc_not_zero(&new_hard_iface->refcount))
 131                 new_hard_iface = NULL;
 132
 133         curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
 134         rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
 135
 136         if (!new_hard_iface)
 137                 goto out;
 138
 139         bat_priv->bat_algo_ops->bat_primary_iface_set(new_hard_iface);
 140         batadv_primary_if_update_addr(bat_priv, curr_hard_iface);
 141
 142 out:
 143         if (curr_hard_iface)
 144                 batadv_hardif_free_ref(curr_hard_iface);
 145 }
 146
 147 static bool
 148 batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
 149 {
 150         if (hard_iface->net_dev->flags & IFF_UP)
 151                 return true;
 152
 153         return false;
 154 }
 155
 156 static void batadv_check_known_mac_addr(const struct net_device *net_dev)
 157 {
 158         const struct batadv_hard_iface *hard_iface;
 159
 160         rcu_read_lock();
 161         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 162                 if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 163                     (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 164                         continue;
 165
 166                 if (hard_iface->net_dev == net_dev)
 167                         continue;
 168
 169                 if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
 170                                         net_dev->dev_addr))
 171                         continue;
 172
 173                 pr_warn("The newly added mac address (%pM) already exists on: %s\n",
 174                         net_dev->dev_addr, hard_iface->net_dev->name);
 175                 pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
 176         }
 177         rcu_read_unlock();
 178 }
 179
 180 int batadv_hardif_min_mtu(struct net_device *soft_iface)
 181 {
 182         const struct batadv_priv *bat_priv = netdev_priv(soft_iface);
 183         const struct batadv_hard_iface *hard_iface;
 184         /* allow big frames if all devices are capable to do so
 185          * (have MTU > 1500 + BAT_HEADER_LEN)
 186          */
 187         int min_mtu = ETH_DATA_LEN;
 188
 189         if (atomic_read(&bat_priv->fragmentation))
 190                 goto out;
 191
 192         rcu_read_lock();
 193         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 194                 if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 195                     (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 196                         continue;
 197
 198                 if (hard_iface->soft_iface != soft_iface)
 199                         continue;
 200
 201                 min_mtu = min_t(int,
 202                                 hard_iface->net_dev->mtu - BATADV_HEADER_LEN,
 203                                 min_mtu);
 204         }
 205         rcu_read_unlock();
 206 out:
 207         return min_mtu;
 208 }
 209
 210 /* adjusts the MTU if a new interface with a smaller MTU appeared. */
 211 void batadv_update_min_mtu(struct net_device *soft_iface)
 212 {
 213         int min_mtu;
 214
 215         min_mtu = batadv_hardif_min_mtu(soft_iface);
 216         if (soft_iface->mtu != min_mtu)
 217                 soft_iface->mtu = min_mtu;
 218 }
 219
 220 static void
 221 batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
 222 {
 223         struct batadv_priv *bat_priv;
 224         struct batadv_hard_iface *primary_if = NULL;
 225
 226         if (hard_iface->if_status != BATADV_IF_INACTIVE)
 227                 goto out;
 228
 229         bat_priv = netdev_priv(hard_iface->soft_iface);
 230
 231         bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
 232         hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;
 233
 234         /* the first active interface becomes our primary interface or
 235          * the next active interface after the old primary interface was removed
 236          */
 237         primary_if = batadv_primary_if_get_selected(bat_priv);
 238         if (!primary_if)
 239                 batadv_primary_if_select(bat_priv, hard_iface);
 240
 241         batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
 242                     hard_iface->net_dev->name);
 243
 244         batadv_update_min_mtu(hard_iface->soft_iface);
 245
 246 out:
 247         if (primary_if)
 248                 batadv_hardif_free_ref(primary_if);
 249 }
 250
 251 static void
 252 batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
 253 {
 254         if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 255             (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 256                 return;
 257
 258         hard_iface->if_status = BATADV_IF_INACTIVE;
 259
 260         batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
 261                     hard_iface->net_dev->name);
 262
 263         batadv_update_min_mtu(hard_iface->soft_iface);
 264 }
 265
 266 int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 267                                    const char *iface_name)
 268 {
 269         struct batadv_priv *bat_priv;
 270         struct net_device *soft_iface;
 271         __be16 ethertype = __constant_htons(BATADV_ETH_P_BATMAN);
 272         int ret;
 273
 274         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 275                 goto out;
 276
 277         if (!atomic_inc_not_zero(&hard_iface->refcount))
 278                 goto out;
 279
 280         /* hard-interface is part of a bridge */
 281         if (hard_iface->net_dev->priv_flags & IFF_BRIDGE_PORT)
 282                 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",
 283                        hard_iface->net_dev->name);
 284
 285         soft_iface = dev_get_by_name(&init_net, iface_name);
 286
 287         if (!soft_iface) {
 288                 soft_iface = batadv_softif_create(iface_name);
 289
 290                 if (!soft_iface) {
 291                         ret = -ENOMEM;
 292                         goto err;
 293                 }
 294
 295                 /* dev_get_by_name() increases the reference counter for us */
 296                 dev_hold(soft_iface);
 297         }
 298
 299         if (!batadv_softif_is_valid(soft_iface)) {
 300                 pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
 301                        soft_iface->name);
 302                 ret = -EINVAL;
 303                 goto err_dev;
 304         }
 305
 306         hard_iface->soft_iface = soft_iface;
 307         bat_priv = netdev_priv(hard_iface->soft_iface);
 308
 309         ret = bat_priv->bat_algo_ops->bat_iface_enable(hard_iface);
 310         if (ret < 0)
 311                 goto err_dev;
 312
 313         hard_iface->if_num = bat_priv->num_ifaces;
 314         bat_priv->num_ifaces++;
 315         hard_iface->if_status = BATADV_IF_INACTIVE;
 316         batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
 317
 318         hard_iface->batman_adv_ptype.type = ethertype;
 319         hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
 320         hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
 321         dev_add_pack(&hard_iface->batman_adv_ptype);
 322
 323         atomic_set(&hard_iface->frag_seqno, 1);
 324         batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
 325                     hard_iface->net_dev->name);
 326
 327         if (atomic_read(&bat_priv->fragmentation) &&
 328             hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
 329                 batadv_info(hard_iface->soft_iface,
 330                             "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",
 331                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 332                             ETH_DATA_LEN + BATADV_HEADER_LEN);
 333
 334         if (!atomic_read(&bat_priv->fragmentation) &&
 335             hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
 336                 batadv_info(hard_iface->soft_iface,
 337                             "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",
 338                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 339                             ETH_DATA_LEN + BATADV_HEADER_LEN);
 340
 341         if (batadv_hardif_is_iface_up(hard_iface))
 342                 batadv_hardif_activate_interface(hard_iface);
 343         else
 344                 batadv_err(hard_iface->soft_iface,
 345                            "Not using interface %s (retrying later): interface not active\n",
 346                            hard_iface->net_dev->name);
 347
 348         /* begin scheduling originator messages on that interface */
 349         batadv_schedule_bat_ogm(hard_iface);
 350
 351 out:
 352         return 0;
 353
 354 err_dev:
 355         dev_put(soft_iface);
 356 err:
 357         batadv_hardif_free_ref(hard_iface);
 358         return ret;
 359 }
 360
 361 void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
 362 {
 363         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 364         struct batadv_hard_iface *primary_if = NULL;
 365
 366         if (hard_iface->if_status == BATADV_IF_ACTIVE)
 367                 batadv_hardif_deactivate_interface(hard_iface);
 368
 369         if (hard_iface->if_status != BATADV_IF_INACTIVE)
 370                 goto out;
 371
 372         batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
 373                     hard_iface->net_dev->name);
 374         dev_remove_pack(&hard_iface->batman_adv_ptype);
 375
 376         bat_priv->num_ifaces--;
 377         batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
 378
 379         primary_if = batadv_primary_if_get_selected(bat_priv);
 380         if (hard_iface == primary_if) {
 381                 struct batadv_hard_iface *new_if;
 382
 383                 new_if = batadv_hardif_get_active(hard_iface->soft_iface);
 384                 batadv_primary_if_select(bat_priv, new_if);
 385
 386                 if (new_if)
 387                         batadv_hardif_free_ref(new_if);
 388         }
 389
 390         bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
 391         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 392
 393         /* delete all references to this hard_iface */
 394         batadv_purge_orig_ref(bat_priv);
 395         batadv_purge_outstanding_packets(bat_priv, hard_iface);
 396         dev_put(hard_iface->soft_iface);
 397
 398         /* nobody uses this interface anymore */
 399         if (!bat_priv->num_ifaces)
 400                 batadv_softif_destroy(hard_iface->soft_iface);
 401
 402         hard_iface->soft_iface = NULL;
 403         batadv_hardif_free_ref(hard_iface);
 404
 405 out:
 406         if (primary_if)
 407                 batadv_hardif_free_ref(primary_if);
 408 }
 409
 410 static struct batadv_hard_iface *
 411 batadv_hardif_add_interface(struct net_device *net_dev)
 412 {
 413         struct batadv_hard_iface *hard_iface;
 414         int ret;
 415
 416         ASSERT_RTNL();
 417
 418         ret = batadv_is_valid_iface(net_dev);
 419         if (ret != 1)
 420                 goto out;
 421
 422         dev_hold(net_dev);
 423
 424         hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
 425         if (!hard_iface)
 426                 goto release_dev;
 427
 428         ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
 429         if (ret)
 430                 goto free_if;
 431
 432         hard_iface->if_num = -1;
 433         hard_iface->net_dev = net_dev;
 434         hard_iface->soft_iface = NULL;
 435         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 436         INIT_LIST_HEAD(&hard_iface->list);
 437         /* extra reference for return */
 438         atomic_set(&hard_iface->refcount, 2);
 439
 440         batadv_check_known_mac_addr(hard_iface->net_dev);
 441         list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
 442
 443         /* This can't be called via a bat_priv callback because
 444          * we have no bat_priv yet.
 445          */
 446         atomic_set(&hard_iface->seqno, 1);
 447         hard_iface->packet_buff = NULL;
 448
 449         return hard_iface;
 450
 451 free_if:
 452         kfree(hard_iface);
 453 release_dev:
 454         dev_put(net_dev);
 455 out:
 456         return NULL;
 457 }
 458
 459 static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
 460 {
 461         ASSERT_RTNL();
 462
 463         /* first deactivate interface */
 464         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 465                 batadv_hardif_disable_interface(hard_iface);
 466
 467         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 468                 return;
 469
 470         hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
 471         batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
 472         batadv_hardif_free_ref(hard_iface);
 473 }
 474
 475 void batadv_hardif_remove_interfaces(void)
 476 {
 477         struct batadv_hard_iface *hard_iface, *hard_iface_tmp;
 478
 479         rtnl_lock();
 480         list_for_each_entry_safe(hard_iface, hard_iface_tmp,
 481                                  &batadv_hardif_list, list) {
 482                 list_del_rcu(&hard_iface->list);
 483                 batadv_hardif_remove_interface(hard_iface);
 484         }
 485         rtnl_unlock();
 486 }
 487
 488 static int batadv_hard_if_event(struct notifier_block *this,
 489                                 unsigned long event, void *ptr)
 490 {
 491         struct net_device *net_dev = ptr;
 492         struct batadv_hard_iface *hard_iface;
 493         struct batadv_hard_iface *primary_if = NULL;
 494         struct batadv_priv *bat_priv;
 495
 496         hard_iface = batadv_hardif_get_by_netdev(net_dev);
 497         if (!hard_iface && event == NETDEV_REGISTER)
 498                 hard_iface = batadv_hardif_add_interface(net_dev);
 499
 500         if (!hard_iface)
 501                 goto out;
 502
 503         switch (event) {
 504         case NETDEV_UP:
 505                 batadv_hardif_activate_interface(hard_iface);
 506                 break;
 507         case NETDEV_GOING_DOWN:
 508         case NETDEV_DOWN:
 509                 batadv_hardif_deactivate_interface(hard_iface);
 510                 break;
 511         case NETDEV_UNREGISTER:
 512                 list_del_rcu(&hard_iface->list);
 513
 514                 batadv_hardif_remove_interface(hard_iface);
 515                 break;
 516         case NETDEV_CHANGEMTU:
 517                 if (hard_iface->soft_iface)
 518                         batadv_update_min_mtu(hard_iface->soft_iface);
 519                 break;
 520         case NETDEV_CHANGEADDR:
 521                 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
 522                         goto hardif_put;
 523
 524                 batadv_check_known_mac_addr(hard_iface->net_dev);
 525
 526                 bat_priv = netdev_priv(hard_iface->soft_iface);
 527                 bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
 528
 529                 primary_if = batadv_primary_if_get_selected(bat_priv);
 530                 if (!primary_if)
 531                         goto hardif_put;
 532
 533                 if (hard_iface == primary_if)
 534                         batadv_primary_if_update_addr(bat_priv, NULL);
 535                 break;
 536         default:
 537                 break;
 538         }
 539
 540 hardif_put:
 541         batadv_hardif_free_ref(hard_iface);
 542 out:
 543         if (primary_if)
 544                 batadv_hardif_free_ref(primary_if);
 545         return NOTIFY_DONE;
 546 }
 547
 548 /* This function returns true if the interface represented by ifindex is a
 549  * 802.11 wireless device
 550  */
 551 bool batadv_is_wifi_iface(int ifindex)
 552 {
 553         struct net_device *net_device = NULL;
 554         bool ret = false;
 555
 556         if (ifindex == BATADV_NULL_IFINDEX)
 557                 goto out;
 558
 559         net_device = dev_get_by_index(&init_net, ifindex);
 560         if (!net_device)
 561                 goto out;
 562
 563 #ifdef CONFIG_WIRELESS_EXT
 564         /* pre-cfg80211 drivers have to implement WEXT, so it is possible to
 565          * check for wireless_handlers != NULL
 566          */
 567         if (net_device->wireless_handlers)
 568                 ret = true;
 569         else
 570 #endif
 571                 /* cfg80211 drivers have to set ieee80211_ptr */
 572                 if (net_device->ieee80211_ptr)
 573                         ret = true;
 574 out:
 575         if (net_device)
 576                 dev_put(net_device);
 577         return ret;
 578 }
 579
 580 struct notifier_block batadv_hard_if_notifier = {
 581         .notifier_call = batadv_hard_if_event,
 582 };