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         struct sk_buff *skb;
 107
 108         primary_if = batadv_primary_if_get_selected(bat_priv);
 109         if (!primary_if)
 110                 goto out;
 111
 112         skb = bat_priv->vis.my_info->skb_packet;
 113         vis_packet = (struct batadv_vis_packet *)skb->data;
 114         memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 115         memcpy(vis_packet->sender_orig,
 116                primary_if->net_dev->dev_addr, ETH_ALEN);
 117
 118         batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
 119 out:
 120         if (primary_if)
 121                 batadv_hardif_free_ref(primary_if);
 122 }
 123
 124 static void batadv_primary_if_select(struct batadv_priv *bat_priv,
 125                                      struct batadv_hard_iface *new_hard_iface)
 126 {
 127         struct batadv_hard_iface *curr_hard_iface;
 128
 129         ASSERT_RTNL();
 130
 131         if (new_hard_iface && !atomic_inc_not_zero(&new_hard_iface->refcount))
 132                 new_hard_iface = NULL;
 133
 134         curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
 135         rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
 136
 137         if (!new_hard_iface)
 138                 goto out;
 139
 140         bat_priv->bat_algo_ops->bat_primary_iface_set(new_hard_iface);
 141         batadv_primary_if_update_addr(bat_priv, curr_hard_iface);
 142
 143 out:
 144         if (curr_hard_iface)
 145                 batadv_hardif_free_ref(curr_hard_iface);
 146 }
 147
 148 static bool
 149 batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
 150 {
 151         if (hard_iface->net_dev->flags & IFF_UP)
 152                 return true;
 153
 154         return false;
 155 }
 156
 157 static void batadv_check_known_mac_addr(const struct net_device *net_dev)
 158 {
 159         const struct batadv_hard_iface *hard_iface;
 160
 161         rcu_read_lock();
 162         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 163                 if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 164                     (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 165                         continue;
 166
 167                 if (hard_iface->net_dev == net_dev)
 168                         continue;
 169
 170                 if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
 171                                         net_dev->dev_addr))
 172                         continue;
 173
 174                 pr_warn("The newly added mac address (%pM) already exists on: %s\n",
 175                         net_dev->dev_addr, hard_iface->net_dev->name);
 176                 pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
 177         }
 178         rcu_read_unlock();
 179 }
 180
 181 int batadv_hardif_min_mtu(struct net_device *soft_iface)
 182 {
 183         const struct batadv_priv *bat_priv = netdev_priv(soft_iface);
 184         const struct batadv_hard_iface *hard_iface;
 185         /* allow big frames if all devices are capable to do so
 186          * (have MTU > 1500 + BAT_HEADER_LEN)
 187          */
 188         int min_mtu = ETH_DATA_LEN;
 189
 190         if (atomic_read(&bat_priv->fragmentation))
 191                 goto out;
 192
 193         rcu_read_lock();
 194         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 195                 if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 196                     (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 197                         continue;
 198
 199                 if (hard_iface->soft_iface != soft_iface)
 200                         continue;
 201
 202                 min_mtu = min_t(int,
 203                                 hard_iface->net_dev->mtu - BATADV_HEADER_LEN,
 204                                 min_mtu);
 205         }
 206         rcu_read_unlock();
 207 out:
 208         return min_mtu;
 209 }
 210
 211 /* adjusts the MTU if a new interface with a smaller MTU appeared. */
 212 void batadv_update_min_mtu(struct net_device *soft_iface)
 213 {
 214         int min_mtu;
 215
 216         min_mtu = batadv_hardif_min_mtu(soft_iface);
 217         if (soft_iface->mtu != min_mtu)
 218                 soft_iface->mtu = min_mtu;
 219 }
 220
 221 static void
 222 batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
 223 {
 224         struct batadv_priv *bat_priv;
 225         struct batadv_hard_iface *primary_if = NULL;
 226
 227         if (hard_iface->if_status != BATADV_IF_INACTIVE)
 228                 goto out;
 229
 230         bat_priv = netdev_priv(hard_iface->soft_iface);
 231
 232         bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
 233         hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;
 234
 235         /* the first active interface becomes our primary interface or
 236          * the next active interface after the old primary interface was removed
 237          */
 238         primary_if = batadv_primary_if_get_selected(bat_priv);
 239         if (!primary_if)
 240                 batadv_primary_if_select(bat_priv, hard_iface);
 241
 242         batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
 243                     hard_iface->net_dev->name);
 244
 245         batadv_update_min_mtu(hard_iface->soft_iface);
 246
 247 out:
 248         if (primary_if)
 249                 batadv_hardif_free_ref(primary_if);
 250 }
 251
 252 static void
 253 batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
 254 {
 255         if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 256             (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 257                 return;
 258
 259         hard_iface->if_status = BATADV_IF_INACTIVE;
 260
 261         batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
 262                     hard_iface->net_dev->name);
 263
 264         batadv_update_min_mtu(hard_iface->soft_iface);
 265 }
 266
 267 int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 268                                    const char *iface_name)
 269 {
 270         struct batadv_priv *bat_priv;
 271         struct net_device *soft_iface;
 272         __be16 ethertype = __constant_htons(BATADV_ETH_P_BATMAN);
 273         int ret;
 274
 275         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 276                 goto out;
 277
 278         if (!atomic_inc_not_zero(&hard_iface->refcount))
 279                 goto out;
 280
 281         /* hard-interface is part of a bridge */
 282         if (hard_iface->net_dev->priv_flags & IFF_BRIDGE_PORT)
 283                 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",
 284                        hard_iface->net_dev->name);
 285
 286         soft_iface = dev_get_by_name(&init_net, iface_name);
 287
 288         if (!soft_iface) {
 289                 soft_iface = batadv_softif_create(iface_name);
 290
 291                 if (!soft_iface) {
 292                         ret = -ENOMEM;
 293                         goto err;
 294                 }
 295
 296                 /* dev_get_by_name() increases the reference counter for us */
 297                 dev_hold(soft_iface);
 298         }
 299
 300         if (!batadv_softif_is_valid(soft_iface)) {
 301                 pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
 302                        soft_iface->name);
 303                 ret = -EINVAL;
 304                 goto err_dev;
 305         }
 306
 307         hard_iface->soft_iface = soft_iface;
 308         bat_priv = netdev_priv(hard_iface->soft_iface);
 309
 310         ret = bat_priv->bat_algo_ops->bat_iface_enable(hard_iface);
 311         if (ret < 0)
 312                 goto err_dev;
 313
 314         hard_iface->if_num = bat_priv->num_ifaces;
 315         bat_priv->num_ifaces++;
 316         hard_iface->if_status = BATADV_IF_INACTIVE;
 317         ret = batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
 318         if (ret < 0) {
 319                 bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
 320                 bat_priv->num_ifaces--;
 321                 hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 322                 goto err_dev;
 323         }
 324
 325         hard_iface->batman_adv_ptype.type = ethertype;
 326         hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
 327         hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
 328         dev_add_pack(&hard_iface->batman_adv_ptype);
 329
 330         atomic_set(&hard_iface->frag_seqno, 1);
 331         batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
 332                     hard_iface->net_dev->name);
 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. 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",
 338                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 339                             ETH_DATA_LEN + BATADV_HEADER_LEN);
 340
 341         if (!atomic_read(&bat_priv->fragmentation) &&
 342             hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
 343                 batadv_info(hard_iface->soft_iface,
 344                             "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",
 345                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 346                             ETH_DATA_LEN + BATADV_HEADER_LEN);
 347
 348         if (batadv_hardif_is_iface_up(hard_iface))
 349                 batadv_hardif_activate_interface(hard_iface);
 350         else
 351                 batadv_err(hard_iface->soft_iface,
 352                            "Not using interface %s (retrying later): interface not active\n",
 353                            hard_iface->net_dev->name);
 354
 355         /* begin scheduling originator messages on that interface */
 356         batadv_schedule_bat_ogm(hard_iface);
 357
 358 out:
 359         return 0;
 360
 361 err_dev:
 362         dev_put(soft_iface);
 363 err:
 364         batadv_hardif_free_ref(hard_iface);
 365         return ret;
 366 }
 367
 368 void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
 369 {
 370         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 371         struct batadv_hard_iface *primary_if = NULL;
 372
 373         if (hard_iface->if_status == BATADV_IF_ACTIVE)
 374                 batadv_hardif_deactivate_interface(hard_iface);
 375
 376         if (hard_iface->if_status != BATADV_IF_INACTIVE)
 377                 goto out;
 378
 379         batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
 380                     hard_iface->net_dev->name);
 381         dev_remove_pack(&hard_iface->batman_adv_ptype);
 382
 383         bat_priv->num_ifaces--;
 384         batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
 385
 386         primary_if = batadv_primary_if_get_selected(bat_priv);
 387         if (hard_iface == primary_if) {
 388                 struct batadv_hard_iface *new_if;
 389
 390                 new_if = batadv_hardif_get_active(hard_iface->soft_iface);
 391                 batadv_primary_if_select(bat_priv, new_if);
 392
 393                 if (new_if)
 394                         batadv_hardif_free_ref(new_if);
 395         }
 396
 397         bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
 398         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 399
 400         /* delete all references to this hard_iface */
 401         batadv_purge_orig_ref(bat_priv);
 402         batadv_purge_outstanding_packets(bat_priv, hard_iface);
 403         dev_put(hard_iface->soft_iface);
 404
 405         /* nobody uses this interface anymore */
 406         if (!bat_priv->num_ifaces)
 407                 batadv_softif_destroy(hard_iface->soft_iface);
 408
 409         hard_iface->soft_iface = NULL;
 410         batadv_hardif_free_ref(hard_iface);
 411
 412 out:
 413         if (primary_if)
 414                 batadv_hardif_free_ref(primary_if);
 415 }
 416
 417 static struct batadv_hard_iface *
 418 batadv_hardif_add_interface(struct net_device *net_dev)
 419 {
 420         struct batadv_hard_iface *hard_iface;
 421         int ret;
 422
 423         ASSERT_RTNL();
 424
 425         ret = batadv_is_valid_iface(net_dev);
 426         if (ret != 1)
 427                 goto out;
 428
 429         dev_hold(net_dev);
 430
 431         hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
 432         if (!hard_iface)
 433                 goto release_dev;
 434
 435         ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
 436         if (ret)
 437                 goto free_if;
 438
 439         hard_iface->if_num = -1;
 440         hard_iface->net_dev = net_dev;
 441         hard_iface->soft_iface = NULL;
 442         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 443         INIT_LIST_HEAD(&hard_iface->list);
 444         /* extra reference for return */
 445         atomic_set(&hard_iface->refcount, 2);
 446
 447         batadv_check_known_mac_addr(hard_iface->net_dev);
 448         list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
 449
 450         /* This can't be called via a bat_priv callback because
 451          * we have no bat_priv yet.
 452          */
 453         atomic_set(&hard_iface->seqno, 1);
 454         hard_iface->packet_buff = NULL;
 455
 456         return hard_iface;
 457
 458 free_if:
 459         kfree(hard_iface);
 460 release_dev:
 461         dev_put(net_dev);
 462 out:
 463         return NULL;
 464 }
 465
 466 static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
 467 {
 468         ASSERT_RTNL();
 469
 470         /* first deactivate interface */
 471         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 472                 batadv_hardif_disable_interface(hard_iface);
 473
 474         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 475                 return;
 476
 477         hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
 478         batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
 479         batadv_hardif_free_ref(hard_iface);
 480 }
 481
 482 void batadv_hardif_remove_interfaces(void)
 483 {
 484         struct batadv_hard_iface *hard_iface, *hard_iface_tmp;
 485
 486         rtnl_lock();
 487         list_for_each_entry_safe(hard_iface, hard_iface_tmp,
 488                                  &batadv_hardif_list, list) {
 489                 list_del_rcu(&hard_iface->list);
 490                 batadv_hardif_remove_interface(hard_iface);
 491         }
 492         rtnl_unlock();
 493 }
 494
 495 static int batadv_hard_if_event(struct notifier_block *this,
 496                                 unsigned long event, void *ptr)
 497 {
 498         struct net_device *net_dev = ptr;
 499         struct batadv_hard_iface *hard_iface;
 500         struct batadv_hard_iface *primary_if = NULL;
 501         struct batadv_priv *bat_priv;
 502
 503         hard_iface = batadv_hardif_get_by_netdev(net_dev);
 504         if (!hard_iface && event == NETDEV_REGISTER)
 505                 hard_iface = batadv_hardif_add_interface(net_dev);
 506
 507         if (!hard_iface)
 508                 goto out;
 509
 510         switch (event) {
 511         case NETDEV_UP:
 512                 batadv_hardif_activate_interface(hard_iface);
 513                 break;
 514         case NETDEV_GOING_DOWN:
 515         case NETDEV_DOWN:
 516                 batadv_hardif_deactivate_interface(hard_iface);
 517                 break;
 518         case NETDEV_UNREGISTER:
 519                 list_del_rcu(&hard_iface->list);
 520
 521                 batadv_hardif_remove_interface(hard_iface);
 522                 break;
 523         case NETDEV_CHANGEMTU:
 524                 if (hard_iface->soft_iface)
 525                         batadv_update_min_mtu(hard_iface->soft_iface);
 526                 break;
 527         case NETDEV_CHANGEADDR:
 528                 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
 529                         goto hardif_put;
 530
 531                 batadv_check_known_mac_addr(hard_iface->net_dev);
 532
 533                 bat_priv = netdev_priv(hard_iface->soft_iface);
 534                 bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
 535
 536                 primary_if = batadv_primary_if_get_selected(bat_priv);
 537                 if (!primary_if)
 538                         goto hardif_put;
 539
 540                 if (hard_iface == primary_if)
 541                         batadv_primary_if_update_addr(bat_priv, NULL);
 542                 break;
 543         default:
 544                 break;
 545         }
 546
 547 hardif_put:
 548         batadv_hardif_free_ref(hard_iface);
 549 out:
 550         if (primary_if)
 551                 batadv_hardif_free_ref(primary_if);
 552         return NOTIFY_DONE;
 553 }
 554
 555 /* This function returns true if the interface represented by ifindex is a
 556  * 802.11 wireless device
 557  */
 558 bool batadv_is_wifi_iface(int ifindex)
 559 {
 560         struct net_device *net_device = NULL;
 561         bool ret = false;
 562
 563         if (ifindex == BATADV_NULL_IFINDEX)
 564                 goto out;
 565
 566         net_device = dev_get_by_index(&init_net, ifindex);
 567         if (!net_device)
 568                 goto out;
 569
 570 #ifdef CONFIG_WIRELESS_EXT
 571         /* pre-cfg80211 drivers have to implement WEXT, so it is possible to
 572          * check for wireless_handlers != NULL
 573          */
 574         if (net_device->wireless_handlers)
 575                 ret = true;
 576         else
 577 #endif
 578                 /* cfg80211 drivers have to set ieee80211_ptr */
 579                 if (net_device->ieee80211_ptr)
 580                         ret = true;
 581 out:
 582         if (net_device)
 583                 dev_put(net_device);
 584         return ret;
 585 }
 586
 587 struct notifier_block batadv_hard_if_notifier = {
 588         .notifier_call = batadv_hard_if_event,
 589 };