net/batman-adv/routing.c

   1 /* Copyright (C) 2007-2016  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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "routing.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/byteorder/generic.h>
  23 #include <linux/compiler.h>
  24 #include <linux/errno.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/if_ether.h>
  27 #include <linux/jiffies.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/printk.h>
  30 #include <linux/rculist.h>
  31 #include <linux/rcupdate.h>
  32 #include <linux/skbuff.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/stddef.h>
  35
  36 #include "bitarray.h"
  37 #include "bridge_loop_avoidance.h"
  38 #include "distributed-arp-table.h"
  39 #include "fragmentation.h"
  40 #include "hard-interface.h"
  41 #include "icmp_socket.h"
  42 #include "network-coding.h"
  43 #include "originator.h"
  44 #include "packet.h"
  45 #include "send.h"
  46 #include "soft-interface.h"
  47 #include "translation-table.h"
  48
  49 static int batadv_route_unicast_packet(struct sk_buff *skb,
  50                                        struct batadv_hard_iface *recv_if);
  51
  52 /**
  53  * _batadv_update_route - set the router for this originator
  54  * @bat_priv: the bat priv with all the soft interface information
  55  * @orig_node: orig node which is to be configured
  56  * @recv_if: the receive interface for which this route is set
  57  * @neigh_node: neighbor which should be the next router
  58  *
  59  * This function does not perform any error checks
  60  */
  61 static void _batadv_update_route(struct batadv_priv *bat_priv,
  62                                  struct batadv_orig_node *orig_node,
  63                                  struct batadv_hard_iface *recv_if,
  64                                  struct batadv_neigh_node *neigh_node)
  65 {
  66         struct batadv_orig_ifinfo *orig_ifinfo;
  67         struct batadv_neigh_node *curr_router;
  68
  69         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  70         if (!orig_ifinfo)
  71                 return;
  72
  73         rcu_read_lock();
  74         curr_router = rcu_dereference(orig_ifinfo->router);
  75         if (curr_router && !atomic_inc_not_zero(&curr_router->refcount))
  76                 curr_router = NULL;
  77         rcu_read_unlock();
  78
  79         /* route deleted */
  80         if ((curr_router) && (!neigh_node)) {
  81                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  82                            "Deleting route towards: %pM\n", orig_node->orig);
  83                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  84                                           "Deleted route towards originator");
  85
  86         /* route added */
  87         } else if ((!curr_router) && (neigh_node)) {
  88                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  89                            "Adding route towards: %pM (via %pM)\n",
  90                            orig_node->orig, neigh_node->addr);
  91         /* route changed */
  92         } else if (neigh_node && curr_router) {
  93                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  94                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  95                            orig_node->orig, neigh_node->addr,
  96                            curr_router->addr);
  97         }
  98
  99         if (curr_router)
 100                 batadv_neigh_node_free_ref(curr_router);
 101
 102         /* increase refcount of new best neighbor */
 103         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
 104                 neigh_node = NULL;
 105
 106         spin_lock_bh(&orig_node->neigh_list_lock);
 107         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
 108         spin_unlock_bh(&orig_node->neigh_list_lock);
 109         batadv_orig_ifinfo_free_ref(orig_ifinfo);
 110
 111         /* decrease refcount of previous best neighbor */
 112         if (curr_router)
 113                 batadv_neigh_node_free_ref(curr_router);
 114 }
 115
 116 /**
 117  * batadv_update_route - set the router for this originator
 118  * @bat_priv: the bat priv with all the soft interface information
 119  * @orig_node: orig node which is to be configured
 120  * @recv_if: the receive interface for which this route is set
 121  * @neigh_node: neighbor which should be the next router
 122  */
 123 void batadv_update_route(struct batadv_priv *bat_priv,
 124                          struct batadv_orig_node *orig_node,
 125                          struct batadv_hard_iface *recv_if,
 126                          struct batadv_neigh_node *neigh_node)
 127 {
 128         struct batadv_neigh_node *router = NULL;
 129
 130         if (!orig_node)
 131                 goto out;
 132
 133         router = batadv_orig_router_get(orig_node, recv_if);
 134
 135         if (router != neigh_node)
 136                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 137
 138 out:
 139         if (router)
 140                 batadv_neigh_node_free_ref(router);
 141 }
 142
 143 /**
 144  * batadv_window_protected - checks whether the host restarted and is in the
 145  *  protection time.
 146  * @bat_priv: the bat priv with all the soft interface information
 147  * @seq_num_diff: difference between the current/received sequence number and
 148  *  the last sequence number
 149  * @seq_old_max_diff: maximum age of sequence number not considered as restart
 150  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
 151  *  is detected
 152  * @protection_started: is set to true if the protection window was started,
 153  *   doesn't change otherwise.
 154  *
 155  * Return:
 156  *  0 if the packet is to be accepted.
 157  *  1 if the packet is to be ignored.
 158  */
 159 int batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 160                             s32 seq_old_max_diff, unsigned long *last_reset,
 161                             bool *protection_started)
 162 {
 163         if (seq_num_diff <= -seq_old_max_diff ||
 164             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 165                 if (!batadv_has_timed_out(*last_reset,
 166                                           BATADV_RESET_PROTECTION_MS))
 167                         return 1;
 168
 169                 *last_reset = jiffies;
 170                 if (protection_started)
 171                         *protection_started = true;
 172                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 173                            "old packet received, start protection\n");
 174         }
 175
 176         return 0;
 177 }
 178
 179 bool batadv_check_management_packet(struct sk_buff *skb,
 180                                     struct batadv_hard_iface *hard_iface,
 181                                     int header_len)
 182 {
 183         struct ethhdr *ethhdr;
 184
 185         /* drop packet if it has not necessary minimum size */
 186         if (unlikely(!pskb_may_pull(skb, header_len)))
 187                 return false;
 188
 189         ethhdr = eth_hdr(skb);
 190
 191         /* packet with broadcast indication but unicast recipient */
 192         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 193                 return false;
 194
 195         /* packet with broadcast sender address */
 196         if (is_broadcast_ether_addr(ethhdr->h_source))
 197                 return false;
 198
 199         /* create a copy of the skb, if needed, to modify it. */
 200         if (skb_cow(skb, 0) < 0)
 201                 return false;
 202
 203         /* keep skb linear */
 204         if (skb_linearize(skb) < 0)
 205                 return false;
 206
 207         return true;
 208 }
 209
 210 /**
 211  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 212  * @bat_priv: the bat priv with all the soft interface information
 213  * @skb: icmp packet to process
 214  *
 215  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 216  * otherwise.
 217  */
 218 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 219                                       struct sk_buff *skb)
 220 {
 221         struct batadv_hard_iface *primary_if = NULL;
 222         struct batadv_orig_node *orig_node = NULL;
 223         struct batadv_icmp_header *icmph;
 224         int res, ret = NET_RX_DROP;
 225
 226         icmph = (struct batadv_icmp_header *)skb->data;
 227
 228         switch (icmph->msg_type) {
 229         case BATADV_ECHO_REPLY:
 230         case BATADV_DESTINATION_UNREACHABLE:
 231         case BATADV_TTL_EXCEEDED:
 232                 /* receive the packet */
 233                 if (skb_linearize(skb) < 0)
 234                         break;
 235
 236                 batadv_socket_receive_packet(icmph, skb->len);
 237                 break;
 238         case BATADV_ECHO_REQUEST:
 239                 /* answer echo request (ping) */
 240                 primary_if = batadv_primary_if_get_selected(bat_priv);
 241                 if (!primary_if)
 242                         goto out;
 243
 244                 /* get routing information */
 245                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 246                 if (!orig_node)
 247                         goto out;
 248
 249                 /* create a copy of the skb, if needed, to modify it. */
 250                 if (skb_cow(skb, ETH_HLEN) < 0)
 251                         goto out;
 252
 253                 icmph = (struct batadv_icmp_header *)skb->data;
 254
 255                 ether_addr_copy(icmph->dst, icmph->orig);
 256                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 257                 icmph->msg_type = BATADV_ECHO_REPLY;
 258                 icmph->ttl = BATADV_TTL;
 259
 260                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 261                 if (res != NET_XMIT_DROP)
 262                         ret = NET_RX_SUCCESS;
 263
 264                 break;
 265         default:
 266                 /* drop unknown type */
 267                 goto out;
 268         }
 269 out:
 270         if (primary_if)
 271                 batadv_hardif_free_ref(primary_if);
 272         if (orig_node)
 273                 batadv_orig_node_free_ref(orig_node);
 274         return ret;
 275 }
 276
 277 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 278                                          struct sk_buff *skb)
 279 {
 280         struct batadv_hard_iface *primary_if = NULL;
 281         struct batadv_orig_node *orig_node = NULL;
 282         struct batadv_icmp_packet *icmp_packet;
 283         int ret = NET_RX_DROP;
 284
 285         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 286
 287         /* send TTL exceeded if packet is an echo request (traceroute) */
 288         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 289                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 290                          icmp_packet->orig, icmp_packet->dst);
 291                 goto out;
 292         }
 293
 294         primary_if = batadv_primary_if_get_selected(bat_priv);
 295         if (!primary_if)
 296                 goto out;
 297
 298         /* get routing information */
 299         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 300         if (!orig_node)
 301                 goto out;
 302
 303         /* create a copy of the skb, if needed, to modify it. */
 304         if (skb_cow(skb, ETH_HLEN) < 0)
 305                 goto out;
 306
 307         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 308
 309         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 310         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 311         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 312         icmp_packet->ttl = BATADV_TTL;
 313
 314         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 315                 ret = NET_RX_SUCCESS;
 316
 317 out:
 318         if (primary_if)
 319                 batadv_hardif_free_ref(primary_if);
 320         if (orig_node)
 321                 batadv_orig_node_free_ref(orig_node);
 322         return ret;
 323 }
 324
 325 int batadv_recv_icmp_packet(struct sk_buff *skb,
 326                             struct batadv_hard_iface *recv_if)
 327 {
 328         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 329         struct batadv_icmp_header *icmph;
 330         struct batadv_icmp_packet_rr *icmp_packet_rr;
 331         struct ethhdr *ethhdr;
 332         struct batadv_orig_node *orig_node = NULL;
 333         int hdr_size = sizeof(struct batadv_icmp_header);
 334         int ret = NET_RX_DROP;
 335
 336         /* drop packet if it has not necessary minimum size */
 337         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 338                 goto out;
 339
 340         ethhdr = eth_hdr(skb);
 341
 342         /* packet with unicast indication but broadcast recipient */
 343         if (is_broadcast_ether_addr(ethhdr->h_dest))
 344                 goto out;
 345
 346         /* packet with broadcast sender address */
 347         if (is_broadcast_ether_addr(ethhdr->h_source))
 348                 goto out;
 349
 350         /* not for me */
 351         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 352                 goto out;
 353
 354         icmph = (struct batadv_icmp_header *)skb->data;
 355
 356         /* add record route information if not full */
 357         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 358              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 359             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 360                 if (skb_linearize(skb) < 0)
 361                         goto out;
 362
 363                 /* create a copy of the skb, if needed, to modify it. */
 364                 if (skb_cow(skb, ETH_HLEN) < 0)
 365                         goto out;
 366
 367                 icmph = (struct batadv_icmp_header *)skb->data;
 368                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 369                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 370                         goto out;
 371
 372                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 373                                 ethhdr->h_dest);
 374                 icmp_packet_rr->rr_cur++;
 375         }
 376
 377         /* packet for me */
 378         if (batadv_is_my_mac(bat_priv, icmph->dst))
 379                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 380
 381         /* TTL exceeded */
 382         if (icmph->ttl < 2)
 383                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 384
 385         /* get routing information */
 386         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 387         if (!orig_node)
 388                 goto out;
 389
 390         /* create a copy of the skb, if needed, to modify it. */
 391         if (skb_cow(skb, ETH_HLEN) < 0)
 392                 goto out;
 393
 394         icmph = (struct batadv_icmp_header *)skb->data;
 395
 396         /* decrement ttl */
 397         icmph->ttl--;
 398
 399         /* route it */
 400         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 401                 ret = NET_RX_SUCCESS;
 402
 403 out:
 404         if (orig_node)
 405                 batadv_orig_node_free_ref(orig_node);
 406         return ret;
 407 }
 408
 409 /**
 410  * batadv_check_unicast_packet - Check for malformed unicast packets
 411  * @bat_priv: the bat priv with all the soft interface information
 412  * @skb: packet to check
 413  * @hdr_size: size of header to pull
 414  *
 415  * Check for short header and bad addresses in given packet.
 416  *
 417  * Return: negative value when check fails and 0 otherwise. The negative value
 418  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 419  * destination or source, and -EREMOTE for non-local (other host) destination.
 420  */
 421 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 422                                        struct sk_buff *skb, int hdr_size)
 423 {
 424         struct ethhdr *ethhdr;
 425
 426         /* drop packet if it has not necessary minimum size */
 427         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 428                 return -ENODATA;
 429
 430         ethhdr = eth_hdr(skb);
 431
 432         /* packet with unicast indication but broadcast recipient */
 433         if (is_broadcast_ether_addr(ethhdr->h_dest))
 434                 return -EBADR;
 435
 436         /* packet with broadcast sender address */
 437         if (is_broadcast_ether_addr(ethhdr->h_source))
 438                 return -EBADR;
 439
 440         /* not for me */
 441         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 442                 return -EREMOTE;
 443
 444         return 0;
 445 }
 446
 447 /**
 448  * batadv_find_router - find a suitable router for this originator
 449  * @bat_priv: the bat priv with all the soft interface information
 450  * @orig_node: the destination node
 451  * @recv_if: pointer to interface this packet was received on
 452  *
 453  * Return: the router which should be used for this orig_node on
 454  * this interface, or NULL if not available.
 455  */
 456 struct batadv_neigh_node *
 457 batadv_find_router(struct batadv_priv *bat_priv,
 458                    struct batadv_orig_node *orig_node,
 459                    struct batadv_hard_iface *recv_if)
 460 {
 461         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 462         struct batadv_neigh_node *first_candidate_router = NULL;
 463         struct batadv_neigh_node *next_candidate_router = NULL;
 464         struct batadv_neigh_node *router, *cand_router = NULL;
 465         struct batadv_neigh_node *last_cand_router = NULL;
 466         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 467         struct batadv_orig_ifinfo *next_candidate = NULL;
 468         struct batadv_orig_ifinfo *last_candidate;
 469         bool last_candidate_found = false;
 470
 471         if (!orig_node)
 472                 return NULL;
 473
 474         router = batadv_orig_router_get(orig_node, recv_if);
 475
 476         if (!router)
 477                 return router;
 478
 479         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 480          * and if activated.
 481          */
 482         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 483                 return router;
 484
 485         /* bonding: loop through the list of possible routers found
 486          * for the various outgoing interfaces and find a candidate after
 487          * the last chosen bonding candidate (next_candidate). If no such
 488          * router is found, use the first candidate found (the previously
 489          * chosen bonding candidate might have been the last one in the list).
 490          * If this can't be found either, return the previously chosen
 491          * router - obviously there are no other candidates.
 492          */
 493         rcu_read_lock();
 494         last_candidate = orig_node->last_bonding_candidate;
 495         if (last_candidate)
 496                 last_cand_router = rcu_dereference(last_candidate->router);
 497
 498         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 499                 /* acquire some structures and references ... */
 500                 if (!atomic_inc_not_zero(&cand->refcount))
 501                         continue;
 502
 503                 cand_router = rcu_dereference(cand->router);
 504                 if (!cand_router)
 505                         goto next;
 506
 507                 if (!atomic_inc_not_zero(&cand_router->refcount)) {
 508                         cand_router = NULL;
 509                         goto next;
 510                 }
 511
 512                 /* alternative candidate should be good enough to be
 513                  * considered
 514                  */
 515                 if (!bao->bat_neigh_is_similar_or_better(cand_router,
 516                                                          cand->if_outgoing,
 517                                                          router, recv_if))
 518                         goto next;
 519
 520                 /* don't use the same router twice */
 521                 if (last_cand_router == cand_router)
 522                         goto next;
 523
 524                 /* mark the first possible candidate */
 525                 if (!first_candidate) {
 526                         atomic_inc(&cand_router->refcount);
 527                         atomic_inc(&cand->refcount);
 528                         first_candidate = cand;
 529                         first_candidate_router = cand_router;
 530                 }
 531
 532                 /* check if the loop has already passed the previously selected
 533                  * candidate ... this function should select the next candidate
 534                  * AFTER the previously used bonding candidate.
 535                  */
 536                 if (!last_candidate || last_candidate_found) {
 537                         next_candidate = cand;
 538                         next_candidate_router = cand_router;
 539                         break;
 540                 }
 541
 542                 if (last_candidate == cand)
 543                         last_candidate_found = true;
 544 next:
 545                 /* free references */
 546                 if (cand_router) {
 547                         batadv_neigh_node_free_ref(cand_router);
 548                         cand_router = NULL;
 549                 }
 550                 batadv_orig_ifinfo_free_ref(cand);
 551         }
 552         rcu_read_unlock();
 553
 554         /* last_bonding_candidate is reset below, remove the old reference. */
 555         if (orig_node->last_bonding_candidate)
 556                 batadv_orig_ifinfo_free_ref(orig_node->last_bonding_candidate);
 557
 558         /* After finding candidates, handle the three cases:
 559          * 1) there is a next candidate, use that
 560          * 2) there is no next candidate, use the first of the list
 561          * 3) there is no candidate at all, return the default router
 562          */
 563         if (next_candidate) {
 564                 batadv_neigh_node_free_ref(router);
 565
 566                 /* remove references to first candidate, we don't need it. */
 567                 if (first_candidate) {
 568                         batadv_neigh_node_free_ref(first_candidate_router);
 569                         batadv_orig_ifinfo_free_ref(first_candidate);
 570                 }
 571                 router = next_candidate_router;
 572                 orig_node->last_bonding_candidate = next_candidate;
 573         } else if (first_candidate) {
 574                 batadv_neigh_node_free_ref(router);
 575
 576                 /* refcounting has already been done in the loop above. */
 577                 router = first_candidate_router;
 578                 orig_node->last_bonding_candidate = first_candidate;
 579         } else {
 580                 orig_node->last_bonding_candidate = NULL;
 581         }
 582
 583         return router;
 584 }
 585
 586 static int batadv_route_unicast_packet(struct sk_buff *skb,
 587                                        struct batadv_hard_iface *recv_if)
 588 {
 589         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 590         struct batadv_orig_node *orig_node = NULL;
 591         struct batadv_unicast_packet *unicast_packet;
 592         struct ethhdr *ethhdr = eth_hdr(skb);
 593         int res, hdr_len, ret = NET_RX_DROP;
 594
 595         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 596
 597         /* TTL exceeded */
 598         if (unicast_packet->ttl < 2) {
 599                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 600                          ethhdr->h_source, unicast_packet->dest);
 601                 goto out;
 602         }
 603
 604         /* get routing information */
 605         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 606
 607         if (!orig_node)
 608                 goto out;
 609
 610         /* create a copy of the skb, if needed, to modify it. */
 611         if (skb_cow(skb, ETH_HLEN) < 0)
 612                 goto out;
 613
 614         /* decrement ttl */
 615         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 616         unicast_packet->ttl--;
 617
 618         switch (unicast_packet->packet_type) {
 619         case BATADV_UNICAST_4ADDR:
 620                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 621                 break;
 622         case BATADV_UNICAST:
 623                 hdr_len = sizeof(struct batadv_unicast_packet);
 624                 break;
 625         default:
 626                 /* other packet types not supported - yet */
 627                 hdr_len = -1;
 628                 break;
 629         }
 630
 631         if (hdr_len > 0)
 632                 batadv_skb_set_priority(skb, hdr_len);
 633
 634         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 635
 636         /* translate transmit result into receive result */
 637         if (res == NET_XMIT_SUCCESS) {
 638                 /* skb was transmitted and consumed */
 639                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 640                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 641                                    skb->len + ETH_HLEN);
 642
 643                 ret = NET_RX_SUCCESS;
 644         } else if (res == NET_XMIT_POLICED) {
 645                 /* skb was buffered and consumed */
 646                 ret = NET_RX_SUCCESS;
 647         }
 648
 649 out:
 650         if (orig_node)
 651                 batadv_orig_node_free_ref(orig_node);
 652         return ret;
 653 }
 654
 655 /**
 656  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 657  * @bat_priv: the bat priv with all the soft interface information
 658  * @unicast_packet: the unicast header to be updated
 659  * @dst_addr: the payload destination
 660  * @vid: VLAN identifier
 661  *
 662  * Search the translation table for dst_addr and update the unicast header with
 663  * the new corresponding information (originator address where the destination
 664  * client currently is and its known TTVN)
 665  *
 666  * Return: true if the packet header has been updated, false otherwise
 667  */
 668 static bool
 669 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 670                               struct batadv_unicast_packet *unicast_packet,
 671                               u8 *dst_addr, unsigned short vid)
 672 {
 673         struct batadv_orig_node *orig_node = NULL;
 674         struct batadv_hard_iface *primary_if = NULL;
 675         bool ret = false;
 676         u8 *orig_addr, orig_ttvn;
 677
 678         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 679                 primary_if = batadv_primary_if_get_selected(bat_priv);
 680                 if (!primary_if)
 681                         goto out;
 682                 orig_addr = primary_if->net_dev->dev_addr;
 683                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 684         } else {
 685                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 686                                                      vid);
 687                 if (!orig_node)
 688                         goto out;
 689
 690                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 691                         goto out;
 692
 693                 orig_addr = orig_node->orig;
 694                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 695         }
 696
 697         /* update the packet header */
 698         ether_addr_copy(unicast_packet->dest, orig_addr);
 699         unicast_packet->ttvn = orig_ttvn;
 700
 701         ret = true;
 702 out:
 703         if (primary_if)
 704                 batadv_hardif_free_ref(primary_if);
 705         if (orig_node)
 706                 batadv_orig_node_free_ref(orig_node);
 707
 708         return ret;
 709 }
 710
 711 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 712                                      struct sk_buff *skb, int hdr_len) {
 713         struct batadv_unicast_packet *unicast_packet;
 714         struct batadv_hard_iface *primary_if;
 715         struct batadv_orig_node *orig_node;
 716         u8 curr_ttvn, old_ttvn;
 717         struct ethhdr *ethhdr;
 718         unsigned short vid;
 719         int is_old_ttvn;
 720
 721         /* check if there is enough data before accessing it */
 722         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 723                 return 0;
 724
 725         /* create a copy of the skb (in case of for re-routing) to modify it. */
 726         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 727                 return 0;
 728
 729         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 730         vid = batadv_get_vid(skb, hdr_len);
 731         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 732
 733         /* check if the destination client was served by this node and it is now
 734          * roaming. In this case, it means that the node has got a ROAM_ADV
 735          * message and that it knows the new destination in the mesh to re-route
 736          * the packet to
 737          */
 738         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 739                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 740                                                   ethhdr->h_dest, vid))
 741                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 742                                                bat_priv,
 743                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 744                                                unicast_packet->dest,
 745                                                ethhdr->h_dest);
 746                 /* at this point the mesh destination should have been
 747                  * substituted with the originator address found in the global
 748                  * table. If not, let the packet go untouched anyway because
 749                  * there is nothing the node can do
 750                  */
 751                 return 1;
 752         }
 753
 754         /* retrieve the TTVN known by this node for the packet destination. This
 755          * value is used later to check if the node which sent (or re-routed
 756          * last time) the packet had an updated information or not
 757          */
 758         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 759         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 760                 orig_node = batadv_orig_hash_find(bat_priv,
 761                                                   unicast_packet->dest);
 762                 /* if it is not possible to find the orig_node representing the
 763                  * destination, the packet can immediately be dropped as it will
 764                  * not be possible to deliver it
 765                  */
 766                 if (!orig_node)
 767                         return 0;
 768
 769                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 770                 batadv_orig_node_free_ref(orig_node);
 771         }
 772
 773         /* check if the TTVN contained in the packet is fresher than what the
 774          * node knows
 775          */
 776         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 777         if (!is_old_ttvn)
 778                 return 1;
 779
 780         old_ttvn = unicast_packet->ttvn;
 781         /* the packet was forged based on outdated network information. Its
 782          * destination can possibly be updated and forwarded towards the new
 783          * target host
 784          */
 785         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 786                                           ethhdr->h_dest, vid)) {
 787                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 788                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 789                                        unicast_packet->dest, ethhdr->h_dest,
 790                                        old_ttvn, curr_ttvn);
 791                 return 1;
 792         }
 793
 794         /* the packet has not been re-routed: either the destination is
 795          * currently served by this node or there is no destination at all and
 796          * it is possible to drop the packet
 797          */
 798         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 799                 return 0;
 800
 801         /* update the header in order to let the packet be delivered to this
 802          * node's soft interface
 803          */
 804         primary_if = batadv_primary_if_get_selected(bat_priv);
 805         if (!primary_if)
 806                 return 0;
 807
 808         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 809
 810         batadv_hardif_free_ref(primary_if);
 811
 812         unicast_packet->ttvn = curr_ttvn;
 813
 814         return 1;
 815 }
 816
 817 /**
 818  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 819  *      are in the unicast number space but not yet known to the implementation
 820  * @skb: unicast tvlv packet to process
 821  * @recv_if: pointer to interface this packet was received on
 822  *
 823  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 824  * otherwise.
 825  */
 826 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 827                                          struct batadv_hard_iface *recv_if)
 828 {
 829         struct batadv_unicast_packet *unicast_packet;
 830         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 831         int check, hdr_size = sizeof(*unicast_packet);
 832
 833         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 834         if (check < 0)
 835                 return NET_RX_DROP;
 836
 837         /* we don't know about this type, drop it. */
 838         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 839         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 840                 return NET_RX_DROP;
 841
 842         return batadv_route_unicast_packet(skb, recv_if);
 843 }
 844
 845 int batadv_recv_unicast_packet(struct sk_buff *skb,
 846                                struct batadv_hard_iface *recv_if)
 847 {
 848         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 849         struct batadv_unicast_packet *unicast_packet;
 850         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 851         u8 *orig_addr;
 852         struct batadv_orig_node *orig_node = NULL;
 853         int check, hdr_size = sizeof(*unicast_packet);
 854         enum batadv_subtype subtype;
 855         bool is4addr;
 856
 857         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 858         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 859
 860         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 861         /* the caller function should have already pulled 2 bytes */
 862         if (is4addr)
 863                 hdr_size = sizeof(*unicast_4addr_packet);
 864
 865         /* function returns -EREMOTE for promiscuous packets */
 866         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 867
 868         /* Even though the packet is not for us, we might save it to use for
 869          * decoding a later received coded packet
 870          */
 871         if (check == -EREMOTE)
 872                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 873
 874         if (check < 0)
 875                 return NET_RX_DROP;
 876         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 877                 return NET_RX_DROP;
 878
 879         /* packet for me */
 880         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 881                 if (is4addr) {
 882                         subtype = unicast_4addr_packet->subtype;
 883                         batadv_dat_inc_counter(bat_priv, subtype);
 884
 885                         /* Only payload data should be considered for speedy
 886                          * join. For example, DAT also uses unicast 4addr
 887                          * types, but those packets should not be considered
 888                          * for speedy join, since the clients do not actually
 889                          * reside at the sending originator.
 890                          */
 891                         if (subtype == BATADV_P_DATA) {
 892                                 orig_addr = unicast_4addr_packet->src;
 893                                 orig_node = batadv_orig_hash_find(bat_priv,
 894                                                                   orig_addr);
 895                         }
 896                 }
 897
 898                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 899                                                           hdr_size))
 900                         goto rx_success;
 901                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 902                                                         hdr_size))
 903                         goto rx_success;
 904
 905                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 906                                     orig_node);
 907
 908 rx_success:
 909                 if (orig_node)
 910                         batadv_orig_node_free_ref(orig_node);
 911
 912                 return NET_RX_SUCCESS;
 913         }
 914
 915         return batadv_route_unicast_packet(skb, recv_if);
 916 }
 917
 918 /**
 919  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 920  * @skb: unicast tvlv packet to process
 921  * @recv_if: pointer to interface this packet was received on
 922  *
 923  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 924  * otherwise.
 925  */
 926 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 927                              struct batadv_hard_iface *recv_if)
 928 {
 929         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 930         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 931         unsigned char *tvlv_buff;
 932         u16 tvlv_buff_len;
 933         int hdr_size = sizeof(*unicast_tvlv_packet);
 934         int ret = NET_RX_DROP;
 935
 936         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 937                 return NET_RX_DROP;
 938
 939         /* the header is likely to be modified while forwarding */
 940         if (skb_cow(skb, hdr_size) < 0)
 941                 return NET_RX_DROP;
 942
 943         /* packet needs to be linearized to access the tvlv content */
 944         if (skb_linearize(skb) < 0)
 945                 return NET_RX_DROP;
 946
 947         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 948
 949         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 950         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 951
 952         if (tvlv_buff_len > skb->len - hdr_size)
 953                 return NET_RX_DROP;
 954
 955         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
 956                                              unicast_tvlv_packet->src,
 957                                              unicast_tvlv_packet->dst,
 958                                              tvlv_buff, tvlv_buff_len);
 959
 960         if (ret != NET_RX_SUCCESS)
 961                 ret = batadv_route_unicast_packet(skb, recv_if);
 962         else
 963                 consume_skb(skb);
 964
 965         return ret;
 966 }
 967
 968 /**
 969  * batadv_recv_frag_packet - process received fragment
 970  * @skb: the received fragment
 971  * @recv_if: interface that the skb is received on
 972  *
 973  * This function does one of the three following things: 1) Forward fragment, if
 974  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
 975  * lack further fragments; 3) Merge fragments, if we have all needed parts.
 976  *
 977  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
 978  */
 979 int batadv_recv_frag_packet(struct sk_buff *skb,
 980                             struct batadv_hard_iface *recv_if)
 981 {
 982         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 983         struct batadv_orig_node *orig_node_src = NULL;
 984         struct batadv_frag_packet *frag_packet;
 985         int ret = NET_RX_DROP;
 986
 987         if (batadv_check_unicast_packet(bat_priv, skb,
 988                                         sizeof(*frag_packet)) < 0)
 989                 goto out;
 990
 991         frag_packet = (struct batadv_frag_packet *)skb->data;
 992         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
 993         if (!orig_node_src)
 994                 goto out;
 995
 996         /* Route the fragment if it is not for us and too big to be merged. */
 997         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
 998             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
 999                 ret = NET_RX_SUCCESS;
1000                 goto out;
1001         }
1002
1003         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1004         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1005
1006         /* Add fragment to buffer and merge if possible. */
1007         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1008                 goto out;
1009
1010         /* Deliver merged packet to the appropriate handler, if it was
1011          * merged
1012          */
1013         if (skb)
1014                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1015                                        &recv_if->batman_adv_ptype, NULL);
1016
1017         ret = NET_RX_SUCCESS;
1018
1019 out:
1020         if (orig_node_src)
1021                 batadv_orig_node_free_ref(orig_node_src);
1022
1023         return ret;
1024 }
1025
1026 int batadv_recv_bcast_packet(struct sk_buff *skb,
1027                              struct batadv_hard_iface *recv_if)
1028 {
1029         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1030         struct batadv_orig_node *orig_node = NULL;
1031         struct batadv_bcast_packet *bcast_packet;
1032         struct ethhdr *ethhdr;
1033         int hdr_size = sizeof(*bcast_packet);
1034         int ret = NET_RX_DROP;
1035         s32 seq_diff;
1036         u32 seqno;
1037
1038         /* drop packet if it has not necessary minimum size */
1039         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1040                 goto out;
1041
1042         ethhdr = eth_hdr(skb);
1043
1044         /* packet with broadcast indication but unicast recipient */
1045         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1046                 goto out;
1047
1048         /* packet with broadcast sender address */
1049         if (is_broadcast_ether_addr(ethhdr->h_source))
1050                 goto out;
1051
1052         /* ignore broadcasts sent by myself */
1053         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1054                 goto out;
1055
1056         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1057
1058         /* ignore broadcasts originated by myself */
1059         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1060                 goto out;
1061
1062         if (bcast_packet->ttl < 2)
1063                 goto out;
1064
1065         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1066
1067         if (!orig_node)
1068                 goto out;
1069
1070         spin_lock_bh(&orig_node->bcast_seqno_lock);
1071
1072         seqno = ntohl(bcast_packet->seqno);
1073         /* check whether the packet is a duplicate */
1074         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1075                             seqno))
1076                 goto spin_unlock;
1077
1078         seq_diff = seqno - orig_node->last_bcast_seqno;
1079
1080         /* check whether the packet is old and the host just restarted. */
1081         if (batadv_window_protected(bat_priv, seq_diff,
1082                                     BATADV_BCAST_MAX_AGE,
1083                                     &orig_node->bcast_seqno_reset, NULL))
1084                 goto spin_unlock;
1085
1086         /* mark broadcast in flood history, update window position
1087          * if required.
1088          */
1089         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1090                 orig_node->last_bcast_seqno = seqno;
1091
1092         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1093
1094         /* check whether this has been sent by another originator before */
1095         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1096                 goto out;
1097
1098         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1099
1100         /* rebroadcast packet */
1101         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1102
1103         /* don't hand the broadcast up if it is from an originator
1104          * from the same backbone.
1105          */
1106         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1107                 goto out;
1108
1109         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1110                 goto rx_success;
1111         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1112                 goto rx_success;
1113
1114         /* broadcast for me */
1115         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1116                             orig_node);
1117
1118 rx_success:
1119         ret = NET_RX_SUCCESS;
1120         goto out;
1121
1122 spin_unlock:
1123         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1124 out:
1125         if (orig_node)
1126                 batadv_orig_node_free_ref(orig_node);
1127         return ret;
1128 }