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