net/batman-adv/hard-interface.c

   1 /*
   2  * Copyright (C) 2007-2011 B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner, Simon Wunderlich
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #include "main.h"
  23 #include "hard-interface.h"
  24 #include "soft-interface.h"
  25 #include "send.h"
  26 #include "translation-table.h"
  27 #include "routing.h"
  28 #include "bat_sysfs.h"
  29 #include "originator.h"
  30 #include "hash.h"
  31
  32 #include <linux/if_arp.h>
  33
  34 /* protect update critical side of if_list - but not the content */
  35 static DEFINE_SPINLOCK(if_list_lock);
  36
  37
  38 static int batman_skb_recv(struct sk_buff *skb,
  39                            struct net_device *dev,
  40                            struct packet_type *ptype,
  41                            struct net_device *orig_dev);
  42
  43 static void hardif_free_rcu(struct rcu_head *rcu)
  44 {
  45         struct batman_if *batman_if;
  46
  47         batman_if = container_of(rcu, struct batman_if, rcu);
  48         dev_put(batman_if->net_dev);
  49         kref_put(&batman_if->refcount, hardif_free_ref);
  50 }
  51
  52 struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev)
  53 {
  54         struct batman_if *batman_if;
  55
  56         rcu_read_lock();
  57         list_for_each_entry_rcu(batman_if, &if_list, list) {
  58                 if (batman_if->net_dev == net_dev)
  59                         goto out;
  60         }
  61
  62         batman_if = NULL;
  63
  64 out:
  65         if (batman_if)
  66                 kref_get(&batman_if->refcount);
  67
  68         rcu_read_unlock();
  69         return batman_if;
  70 }
  71
  72 static int is_valid_iface(struct net_device *net_dev)
  73 {
  74         if (net_dev->flags & IFF_LOOPBACK)
  75                 return 0;
  76
  77         if (net_dev->type != ARPHRD_ETHER)
  78                 return 0;
  79
  80         if (net_dev->addr_len != ETH_ALEN)
  81                 return 0;
  82
  83         /* no batman over batman */
  84 #ifdef HAVE_NET_DEVICE_OPS
  85         if (net_dev->netdev_ops->ndo_start_xmit == interface_tx)
  86                 return 0;
  87 #else
  88         if (net_dev->hard_start_xmit == interface_tx)
  89                 return 0;
  90 #endif
  91
  92         /* Device is being bridged */
  93         /* if (net_dev->priv_flags & IFF_BRIDGE_PORT)
  94                 return 0; */
  95
  96         return 1;
  97 }
  98
  99 static struct batman_if *get_active_batman_if(struct net_device *soft_iface)
 100 {
 101         struct batman_if *batman_if;
 102
 103         rcu_read_lock();
 104         list_for_each_entry_rcu(batman_if, &if_list, list) {
 105                 if (batman_if->soft_iface != soft_iface)
 106                         continue;
 107
 108                 if (batman_if->if_status == IF_ACTIVE)
 109                         goto out;
 110         }
 111
 112         batman_if = NULL;
 113
 114 out:
 115         if (batman_if)
 116                 kref_get(&batman_if->refcount);
 117
 118         rcu_read_unlock();
 119         return batman_if;
 120 }
 121
 122 static void update_primary_addr(struct bat_priv *bat_priv)
 123 {
 124         struct vis_packet *vis_packet;
 125
 126         vis_packet = (struct vis_packet *)
 127                                 bat_priv->my_vis_info->skb_packet->data;
 128         memcpy(vis_packet->vis_orig,
 129                bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 130         memcpy(vis_packet->sender_orig,
 131                bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 132 }
 133
 134 static void set_primary_if(struct bat_priv *bat_priv,
 135                            struct batman_if *batman_if)
 136 {
 137         struct batman_packet *batman_packet;
 138         struct batman_if *old_if;
 139
 140         if (batman_if)
 141                 kref_get(&batman_if->refcount);
 142
 143         old_if = bat_priv->primary_if;
 144         bat_priv->primary_if = batman_if;
 145
 146         if (old_if)
 147                 kref_put(&old_if->refcount, hardif_free_ref);
 148
 149         if (!bat_priv->primary_if)
 150                 return;
 151
 152         batman_packet = (struct batman_packet *)(batman_if->packet_buff);
 153         batman_packet->flags = PRIMARIES_FIRST_HOP;
 154         batman_packet->ttl = TTL;
 155
 156         update_primary_addr(bat_priv);
 157
 158         /***
 159          * hacky trick to make sure that we send the HNA information via
 160          * our new primary interface
 161          */
 162         atomic_set(&bat_priv->hna_local_changed, 1);
 163 }
 164
 165 static bool hardif_is_iface_up(struct batman_if *batman_if)
 166 {
 167         if (batman_if->net_dev->flags & IFF_UP)
 168                 return true;
 169
 170         return false;
 171 }
 172
 173 static void update_mac_addresses(struct batman_if *batman_if)
 174 {
 175         memcpy(((struct batman_packet *)(batman_if->packet_buff))->orig,
 176                batman_if->net_dev->dev_addr, ETH_ALEN);
 177         memcpy(((struct batman_packet *)(batman_if->packet_buff))->prev_sender,
 178                batman_if->net_dev->dev_addr, ETH_ALEN);
 179 }
 180
 181 static void check_known_mac_addr(struct net_device *net_dev)
 182 {
 183         struct batman_if *batman_if;
 184
 185         rcu_read_lock();
 186         list_for_each_entry_rcu(batman_if, &if_list, list) {
 187                 if ((batman_if->if_status != IF_ACTIVE) &&
 188                     (batman_if->if_status != IF_TO_BE_ACTIVATED))
 189                         continue;
 190
 191                 if (batman_if->net_dev == net_dev)
 192                         continue;
 193
 194                 if (!compare_orig(batman_if->net_dev->dev_addr,
 195                                   net_dev->dev_addr))
 196                         continue;
 197
 198                 pr_warning("The newly added mac address (%pM) already exists "
 199                            "on: %s\n", net_dev->dev_addr,
 200                            batman_if->net_dev->name);
 201                 pr_warning("It is strongly recommended to keep mac addresses "
 202                            "unique to avoid problems!\n");
 203         }
 204         rcu_read_unlock();
 205 }
 206
 207 int hardif_min_mtu(struct net_device *soft_iface)
 208 {
 209         struct bat_priv *bat_priv = netdev_priv(soft_iface);
 210         struct batman_if *batman_if;
 211         /* allow big frames if all devices are capable to do so
 212          * (have MTU > 1500 + BAT_HEADER_LEN) */
 213         int min_mtu = ETH_DATA_LEN;
 214
 215         if (atomic_read(&bat_priv->fragmentation))
 216                 goto out;
 217
 218         rcu_read_lock();
 219         list_for_each_entry_rcu(batman_if, &if_list, list) {
 220                 if ((batman_if->if_status != IF_ACTIVE) &&
 221                     (batman_if->if_status != IF_TO_BE_ACTIVATED))
 222                         continue;
 223
 224                 if (batman_if->soft_iface != soft_iface)
 225                         continue;
 226
 227                 min_mtu = min_t(int, batman_if->net_dev->mtu - BAT_HEADER_LEN,
 228                                 min_mtu);
 229         }
 230         rcu_read_unlock();
 231 out:
 232         return min_mtu;
 233 }
 234
 235 /* adjusts the MTU if a new interface with a smaller MTU appeared. */
 236 void update_min_mtu(struct net_device *soft_iface)
 237 {
 238         int min_mtu;
 239
 240         min_mtu = hardif_min_mtu(soft_iface);
 241         if (soft_iface->mtu != min_mtu)
 242                 soft_iface->mtu = min_mtu;
 243 }
 244
 245 static void hardif_activate_interface(struct batman_if *batman_if)
 246 {
 247         struct bat_priv *bat_priv;
 248
 249         if (batman_if->if_status != IF_INACTIVE)
 250                 return;
 251
 252         bat_priv = netdev_priv(batman_if->soft_iface);
 253
 254         update_mac_addresses(batman_if);
 255         batman_if->if_status = IF_TO_BE_ACTIVATED;
 256
 257         /**
 258          * the first active interface becomes our primary interface or
 259          * the next active interface after the old primay interface was removed
 260          */
 261         if (!bat_priv->primary_if)
 262                 set_primary_if(bat_priv, batman_if);
 263
 264         bat_info(batman_if->soft_iface, "Interface activated: %s\n",
 265                  batman_if->net_dev->name);
 266
 267         update_min_mtu(batman_if->soft_iface);
 268         return;
 269 }
 270
 271 static void hardif_deactivate_interface(struct batman_if *batman_if)
 272 {
 273         if ((batman_if->if_status != IF_ACTIVE) &&
 274            (batman_if->if_status != IF_TO_BE_ACTIVATED))
 275                 return;
 276
 277         batman_if->if_status = IF_INACTIVE;
 278
 279         bat_info(batman_if->soft_iface, "Interface deactivated: %s\n",
 280                  batman_if->net_dev->name);
 281
 282         update_min_mtu(batman_if->soft_iface);
 283 }
 284
 285 int hardif_enable_interface(struct batman_if *batman_if, char *iface_name)
 286 {
 287         struct bat_priv *bat_priv;
 288         struct batman_packet *batman_packet;
 289
 290         if (batman_if->if_status != IF_NOT_IN_USE)
 291                 goto out;
 292
 293         batman_if->soft_iface = dev_get_by_name(&init_net, iface_name);
 294
 295         if (!batman_if->soft_iface) {
 296                 batman_if->soft_iface = softif_create(iface_name);
 297
 298                 if (!batman_if->soft_iface)
 299                         goto err;
 300
 301                 /* dev_get_by_name() increases the reference counter for us */
 302                 dev_hold(batman_if->soft_iface);
 303         }
 304
 305         bat_priv = netdev_priv(batman_if->soft_iface);
 306         batman_if->packet_len = BAT_PACKET_LEN;
 307         batman_if->packet_buff = kmalloc(batman_if->packet_len, GFP_ATOMIC);
 308
 309         if (!batman_if->packet_buff) {
 310                 bat_err(batman_if->soft_iface, "Can't add interface packet "
 311                         "(%s): out of memory\n", batman_if->net_dev->name);
 312                 goto err;
 313         }
 314
 315         batman_packet = (struct batman_packet *)(batman_if->packet_buff);
 316         batman_packet->packet_type = BAT_PACKET;
 317         batman_packet->version = COMPAT_VERSION;
 318         batman_packet->flags = 0;
 319         batman_packet->ttl = 2;
 320         batman_packet->tq = TQ_MAX_VALUE;
 321         batman_packet->num_hna = 0;
 322
 323         batman_if->if_num = bat_priv->num_ifaces;
 324         bat_priv->num_ifaces++;
 325         batman_if->if_status = IF_INACTIVE;
 326         orig_hash_add_if(batman_if, bat_priv->num_ifaces);
 327
 328         batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
 329         batman_if->batman_adv_ptype.func = batman_skb_recv;
 330         batman_if->batman_adv_ptype.dev = batman_if->net_dev;
 331         kref_get(&batman_if->refcount);
 332         dev_add_pack(&batman_if->batman_adv_ptype);
 333
 334         atomic_set(&batman_if->seqno, 1);
 335         atomic_set(&batman_if->frag_seqno, 1);
 336         bat_info(batman_if->soft_iface, "Adding interface: %s\n",
 337                  batman_if->net_dev->name);
 338
 339         if (atomic_read(&bat_priv->fragmentation) && batman_if->net_dev->mtu <
 340                 ETH_DATA_LEN + BAT_HEADER_LEN)
 341                 bat_info(batman_if->soft_iface,
 342                         "The MTU of interface %s is too small (%i) to handle "
 343                         "the transport of batman-adv packets. Packets going "
 344                         "over this interface will be fragmented on layer2 "
 345                         "which could impact the performance. Setting the MTU "
 346                         "to %zi would solve the problem.\n",
 347                         batman_if->net_dev->name, batman_if->net_dev->mtu,
 348                         ETH_DATA_LEN + BAT_HEADER_LEN);
 349
 350         if (!atomic_read(&bat_priv->fragmentation) && batman_if->net_dev->mtu <
 351                 ETH_DATA_LEN + BAT_HEADER_LEN)
 352                 bat_info(batman_if->soft_iface,
 353                         "The MTU of interface %s is too small (%i) to handle "
 354                         "the transport of batman-adv packets. If you experience"
 355                         " problems getting traffic through try increasing the "
 356                         "MTU to %zi.\n",
 357                         batman_if->net_dev->name, batman_if->net_dev->mtu,
 358                         ETH_DATA_LEN + BAT_HEADER_LEN);
 359
 360         if (hardif_is_iface_up(batman_if))
 361                 hardif_activate_interface(batman_if);
 362         else
 363                 bat_err(batman_if->soft_iface, "Not using interface %s "
 364                         "(retrying later): interface not active\n",
 365                         batman_if->net_dev->name);
 366
 367         /* begin scheduling originator messages on that interface */
 368         schedule_own_packet(batman_if);
 369
 370 out:
 371         return 0;
 372
 373 err:
 374         return -ENOMEM;
 375 }
 376
 377 void hardif_disable_interface(struct batman_if *batman_if)
 378 {
 379         struct bat_priv *bat_priv = netdev_priv(batman_if->soft_iface);
 380
 381         if (batman_if->if_status == IF_ACTIVE)
 382                 hardif_deactivate_interface(batman_if);
 383
 384         if (batman_if->if_status != IF_INACTIVE)
 385                 return;
 386
 387         bat_info(batman_if->soft_iface, "Removing interface: %s\n",
 388                  batman_if->net_dev->name);
 389         dev_remove_pack(&batman_if->batman_adv_ptype);
 390         kref_put(&batman_if->refcount, hardif_free_ref);
 391
 392         bat_priv->num_ifaces--;
 393         orig_hash_del_if(batman_if, bat_priv->num_ifaces);
 394
 395         if (batman_if == bat_priv->primary_if) {
 396                 struct batman_if *new_if;
 397
 398                 new_if = get_active_batman_if(batman_if->soft_iface);
 399                 set_primary_if(bat_priv, new_if);
 400
 401                 if (new_if)
 402                         kref_put(&new_if->refcount, hardif_free_ref);
 403         }
 404
 405         kfree(batman_if->packet_buff);
 406         batman_if->packet_buff = NULL;
 407         batman_if->if_status = IF_NOT_IN_USE;
 408
 409         /* delete all references to this batman_if */
 410         purge_orig_ref(bat_priv);
 411         purge_outstanding_packets(bat_priv, batman_if);
 412         dev_put(batman_if->soft_iface);
 413
 414         /* nobody uses this interface anymore */
 415         if (!bat_priv->num_ifaces)
 416                 softif_destroy(batman_if->soft_iface);
 417
 418         batman_if->soft_iface = NULL;
 419 }
 420
 421 static struct batman_if *hardif_add_interface(struct net_device *net_dev)
 422 {
 423         struct batman_if *batman_if;
 424         int ret;
 425
 426         ret = is_valid_iface(net_dev);
 427         if (ret != 1)
 428                 goto out;
 429
 430         dev_hold(net_dev);
 431
 432         batman_if = kmalloc(sizeof(struct batman_if), GFP_ATOMIC);
 433         if (!batman_if) {
 434                 pr_err("Can't add interface (%s): out of memory\n",
 435                        net_dev->name);
 436                 goto release_dev;
 437         }
 438
 439         ret = sysfs_add_hardif(&batman_if->hardif_obj, net_dev);
 440         if (ret)
 441                 goto free_if;
 442
 443         batman_if->if_num = -1;
 444         batman_if->net_dev = net_dev;
 445         batman_if->soft_iface = NULL;
 446         batman_if->if_status = IF_NOT_IN_USE;
 447         INIT_LIST_HEAD(&batman_if->list);
 448         kref_init(&batman_if->refcount);
 449
 450         check_known_mac_addr(batman_if->net_dev);
 451
 452         spin_lock(&if_list_lock);
 453         list_add_tail_rcu(&batman_if->list, &if_list);
 454         spin_unlock(&if_list_lock);
 455
 456         /* extra reference for return */
 457         kref_get(&batman_if->refcount);
 458         return batman_if;
 459
 460 free_if:
 461         kfree(batman_if);
 462 release_dev:
 463         dev_put(net_dev);
 464 out:
 465         return NULL;
 466 }
 467
 468 static void hardif_remove_interface(struct batman_if *batman_if)
 469 {
 470         /* first deactivate interface */
 471         if (batman_if->if_status != IF_NOT_IN_USE)
 472                 hardif_disable_interface(batman_if);
 473
 474         if (batman_if->if_status != IF_NOT_IN_USE)
 475                 return;
 476
 477         batman_if->if_status = IF_TO_BE_REMOVED;
 478         sysfs_del_hardif(&batman_if->hardif_obj);
 479         call_rcu(&batman_if->rcu, hardif_free_rcu);
 480 }
 481
 482 void hardif_remove_interfaces(void)
 483 {
 484         struct batman_if *batman_if, *batman_if_tmp;
 485         struct list_head if_queue;
 486
 487         INIT_LIST_HEAD(&if_queue);
 488
 489         spin_lock(&if_list_lock);
 490         list_for_each_entry_safe(batman_if, batman_if_tmp, &if_list, list) {
 491                 list_del_rcu(&batman_if->list);
 492                 list_add_tail(&batman_if->list, &if_queue);
 493         }
 494         spin_unlock(&if_list_lock);
 495
 496         rtnl_lock();
 497         list_for_each_entry_safe(batman_if, batman_if_tmp, &if_queue, list) {
 498                 hardif_remove_interface(batman_if);
 499         }
 500         rtnl_unlock();
 501 }
 502
 503 static int hard_if_event(struct notifier_block *this,
 504                          unsigned long event, void *ptr)
 505 {
 506         struct net_device *net_dev = (struct net_device *)ptr;
 507         struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
 508         struct bat_priv *bat_priv;
 509
 510         if (!batman_if && event == NETDEV_REGISTER)
 511                 batman_if = hardif_add_interface(net_dev);
 512
 513         if (!batman_if)
 514                 goto out;
 515
 516         switch (event) {
 517         case NETDEV_UP:
 518                 hardif_activate_interface(batman_if);
 519                 break;
 520         case NETDEV_GOING_DOWN:
 521         case NETDEV_DOWN:
 522                 hardif_deactivate_interface(batman_if);
 523                 break;
 524         case NETDEV_UNREGISTER:
 525                 spin_lock(&if_list_lock);
 526                 list_del_rcu(&batman_if->list);
 527                 spin_unlock(&if_list_lock);
 528
 529                 hardif_remove_interface(batman_if);
 530                 break;
 531         case NETDEV_CHANGEMTU:
 532                 if (batman_if->soft_iface)
 533                         update_min_mtu(batman_if->soft_iface);
 534                 break;
 535         case NETDEV_CHANGEADDR:
 536                 if (batman_if->if_status == IF_NOT_IN_USE)
 537                         goto hardif_put;
 538
 539                 check_known_mac_addr(batman_if->net_dev);
 540                 update_mac_addresses(batman_if);
 541
 542                 bat_priv = netdev_priv(batman_if->soft_iface);
 543                 if (batman_if == bat_priv->primary_if)
 544                         update_primary_addr(bat_priv);
 545                 break;
 546         default:
 547                 break;
 548         };
 549
 550 hardif_put:
 551         kref_put(&batman_if->refcount, hardif_free_ref);
 552 out:
 553         return NOTIFY_DONE;
 554 }
 555
 556 /* receive a packet with the batman ethertype coming on a hard
 557  * interface */
 558 static int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
 559                            struct packet_type *ptype,
 560                            struct net_device *orig_dev)
 561 {
 562         struct bat_priv *bat_priv;
 563         struct batman_packet *batman_packet;
 564         struct batman_if *batman_if;
 565         int ret;
 566
 567         batman_if = container_of(ptype, struct batman_if, batman_adv_ptype);
 568         skb = skb_share_check(skb, GFP_ATOMIC);
 569
 570         /* skb was released by skb_share_check() */
 571         if (!skb)
 572                 goto err_out;
 573
 574         /* packet should hold at least type and version */
 575         if (unlikely(!pskb_may_pull(skb, 2)))
 576                 goto err_free;
 577
 578         /* expect a valid ethernet header here. */
 579         if (unlikely(skb->mac_len != sizeof(struct ethhdr)
 580                                 || !skb_mac_header(skb)))
 581                 goto err_free;
 582
 583         if (!batman_if->soft_iface)
 584                 goto err_free;
 585
 586         bat_priv = netdev_priv(batman_if->soft_iface);
 587
 588         if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
 589                 goto err_free;
 590
 591         /* discard frames on not active interfaces */
 592         if (batman_if->if_status != IF_ACTIVE)
 593                 goto err_free;
 594
 595         batman_packet = (struct batman_packet *)skb->data;
 596
 597         if (batman_packet->version != COMPAT_VERSION) {
 598                 bat_dbg(DBG_BATMAN, bat_priv,
 599                         "Drop packet: incompatible batman version (%i)\n",
 600                         batman_packet->version);
 601                 goto err_free;
 602         }
 603
 604         /* all receive handlers return whether they received or reused
 605          * the supplied skb. if not, we have to free the skb. */
 606
 607         switch (batman_packet->packet_type) {
 608                 /* batman originator packet */
 609         case BAT_PACKET:
 610                 ret = recv_bat_packet(skb, batman_if);
 611                 break;
 612
 613                 /* batman icmp packet */
 614         case BAT_ICMP:
 615                 ret = recv_icmp_packet(skb, batman_if);
 616                 break;
 617
 618                 /* unicast packet */
 619         case BAT_UNICAST:
 620                 ret = recv_unicast_packet(skb, batman_if);
 621                 break;
 622
 623                 /* fragmented unicast packet */
 624         case BAT_UNICAST_FRAG:
 625                 ret = recv_ucast_frag_packet(skb, batman_if);
 626                 break;
 627
 628                 /* broadcast packet */
 629         case BAT_BCAST:
 630                 ret = recv_bcast_packet(skb, batman_if);
 631                 break;
 632
 633                 /* vis packet */
 634         case BAT_VIS:
 635                 ret = recv_vis_packet(skb, batman_if);
 636                 break;
 637         default:
 638                 ret = NET_RX_DROP;
 639         }
 640
 641         if (ret == NET_RX_DROP)
 642                 kfree_skb(skb);
 643
 644         /* return NET_RX_SUCCESS in any case as we
 645          * most probably dropped the packet for
 646          * routing-logical reasons. */
 647
 648         return NET_RX_SUCCESS;
 649
 650 err_free:
 651         kfree_skb(skb);
 652 err_out:
 653         return NET_RX_DROP;
 654 }
 655
 656 struct notifier_block hard_if_notifier = {
 657         .notifier_call = hard_if_event,
 658 };