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