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/kref.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/printk.h>
  31 #include <linux/rculist.h>
  32 #include <linux/rcupdate.h>
  33 #include <linux/skbuff.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/stddef.h>
  36
  37 #include "bitarray.h"
  38 #include "bridge_loop_avoidance.h"
  39 #include "distributed-arp-table.h"
  40 #include "fragmentation.h"
  41 #include "hard-interface.h"
  42 #include "icmp_socket.h"
  43 #include "network-coding.h"
  44 #include "originator.h"
  45 #include "packet.h"
  46 #include "send.h"
  47 #include "soft-interface.h"
  48 #include "translation-table.h"
  49
  50 static int batadv_route_unicast_packet(struct sk_buff *skb,
  51                                        struct batadv_hard_iface *recv_if);
  52
  53 /**
  54  * _batadv_update_route - set the router for this originator
  55  * @bat_priv: the bat priv with all the soft interface information
  56  * @orig_node: orig node which is to be configured
  57  * @recv_if: the receive interface for which this route is set
  58  * @neigh_node: neighbor which should be the next router
  59  *
  60  * This function does not perform any error checks
  61  */
  62 static void _batadv_update_route(struct batadv_priv *bat_priv,
  63                                  struct batadv_orig_node *orig_node,
  64                                  struct batadv_hard_iface *recv_if,
  65                                  struct batadv_neigh_node *neigh_node)
  66 {
  67         struct batadv_orig_ifinfo *orig_ifinfo;
  68         struct batadv_neigh_node *curr_router;
  69
  70         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  71         if (!orig_ifinfo)
  72                 return;
  73
  74         rcu_read_lock();
  75         curr_router = rcu_dereference(orig_ifinfo->router);
  76         if (curr_router && !kref_get_unless_zero(&curr_router->refcount))
  77                 curr_router = NULL;
  78         rcu_read_unlock();
  79
  80         /* route deleted */
  81         if ((curr_router) && (!neigh_node)) {
  82                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  83                            "Deleting route towards: %pM\n", orig_node->orig);
  84                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  85                                           "Deleted route towards originator");
  86
  87         /* route added */
  88         } else if ((!curr_router) && (neigh_node)) {
  89                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  90                            "Adding route towards: %pM (via %pM)\n",
  91                            orig_node->orig, neigh_node->addr);
  92         /* route changed */
  93         } else if (neigh_node && curr_router) {
  94                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  95                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  96                            orig_node->orig, neigh_node->addr,
  97                            curr_router->addr);
  98         }
  99
 100         if (curr_router)
 101                 batadv_neigh_node_put(curr_router);
 102
 103         /* increase refcount of new best neighbor */
 104         if (neigh_node && !kref_get_unless_zero(&neigh_node->refcount))
 105                 neigh_node = NULL;
 106
 107         spin_lock_bh(&orig_node->neigh_list_lock);
 108         /* curr_router used earlier may not be the current orig_ifinfo->router
 109          * anymore because it was dereferenced outside of the neigh_list_lock
 110          * protected region. After the new best neighbor has replace the current
 111          * best neighbor the reference counter needs to decrease. Consequently,
 112          * the code needs to ensure the curr_router variable contains a pointer
 113          * to the replaced best neighbor.
 114          */
 115         curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
 116
 117         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
 118         spin_unlock_bh(&orig_node->neigh_list_lock);
 119         batadv_orig_ifinfo_put(orig_ifinfo);
 120
 121         /* decrease refcount of previous best neighbor */
 122         if (curr_router)
 123                 batadv_neigh_node_put(curr_router);
 124 }
 125
 126 /**
 127  * batadv_update_route - set the router for this originator
 128  * @bat_priv: the bat priv with all the soft interface information
 129  * @orig_node: orig node which is to be configured
 130  * @recv_if: the receive interface for which this route is set
 131  * @neigh_node: neighbor which should be the next router
 132  */
 133 void batadv_update_route(struct batadv_priv *bat_priv,
 134                          struct batadv_orig_node *orig_node,
 135                          struct batadv_hard_iface *recv_if,
 136                          struct batadv_neigh_node *neigh_node)
 137 {
 138         struct batadv_neigh_node *router = NULL;
 139
 140         if (!orig_node)
 141                 goto out;
 142
 143         router = batadv_orig_router_get(orig_node, recv_if);
 144
 145         if (router != neigh_node)
 146                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 147
 148 out:
 149         if (router)
 150                 batadv_neigh_node_put(router);
 151 }
 152
 153 /**
 154  * batadv_window_protected - checks whether the host restarted and is in the
 155  *  protection time.
 156  * @bat_priv: the bat priv with all the soft interface information
 157  * @seq_num_diff: difference between the current/received sequence number and
 158  *  the last sequence number
 159  * @seq_old_max_diff: maximum age of sequence number not considered as restart
 160  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
 161  *  is detected
 162  * @protection_started: is set to true if the protection window was started,
 163  *   doesn't change otherwise.
 164  *
 165  * Return:
 166  *  0 if the packet is to be accepted.
 167  *  1 if the packet is to be ignored.
 168  */
 169 int batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 170                             s32 seq_old_max_diff, unsigned long *last_reset,
 171                             bool *protection_started)
 172 {
 173         if (seq_num_diff <= -seq_old_max_diff ||
 174             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 175                 if (!batadv_has_timed_out(*last_reset,
 176                                           BATADV_RESET_PROTECTION_MS))
 177                         return 1;
 178
 179                 *last_reset = jiffies;
 180                 if (protection_started)
 181                         *protection_started = true;
 182                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 183                            "old packet received, start protection\n");
 184         }
 185
 186         return 0;
 187 }
 188
 189 bool batadv_check_management_packet(struct sk_buff *skb,
 190                                     struct batadv_hard_iface *hard_iface,
 191                                     int header_len)
 192 {
 193         struct ethhdr *ethhdr;
 194
 195         /* drop packet if it has not necessary minimum size */
 196         if (unlikely(!pskb_may_pull(skb, header_len)))
 197                 return false;
 198
 199         ethhdr = eth_hdr(skb);
 200
 201         /* packet with broadcast indication but unicast recipient */
 202         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 203                 return false;
 204
 205         /* packet with broadcast sender address */
 206         if (is_broadcast_ether_addr(ethhdr->h_source))
 207                 return false;
 208
 209         /* create a copy of the skb, if needed, to modify it. */
 210         if (skb_cow(skb, 0) < 0)
 211                 return false;
 212
 213         /* keep skb linear */
 214         if (skb_linearize(skb) < 0)
 215                 return false;
 216
 217         return true;
 218 }
 219
 220 /**
 221  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 222  * @bat_priv: the bat priv with all the soft interface information
 223  * @skb: icmp packet to process
 224  *
 225  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 226  * otherwise.
 227  */
 228 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 229                                       struct sk_buff *skb)
 230 {
 231         struct batadv_hard_iface *primary_if = NULL;
 232         struct batadv_orig_node *orig_node = NULL;
 233         struct batadv_icmp_header *icmph;
 234         int res, ret = NET_RX_DROP;
 235
 236         icmph = (struct batadv_icmp_header *)skb->data;
 237
 238         switch (icmph->msg_type) {
 239         case BATADV_ECHO_REPLY:
 240         case BATADV_DESTINATION_UNREACHABLE:
 241         case BATADV_TTL_EXCEEDED:
 242                 /* receive the packet */
 243                 if (skb_linearize(skb) < 0)
 244                         break;
 245
 246                 batadv_socket_receive_packet(icmph, skb->len);
 247                 break;
 248         case BATADV_ECHO_REQUEST:
 249                 /* answer echo request (ping) */
 250                 primary_if = batadv_primary_if_get_selected(bat_priv);
 251                 if (!primary_if)
 252                         goto out;
 253
 254                 /* get routing information */
 255                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 256                 if (!orig_node)
 257                         goto out;
 258
 259                 /* create a copy of the skb, if needed, to modify it. */
 260                 if (skb_cow(skb, ETH_HLEN) < 0)
 261                         goto out;
 262
 263                 icmph = (struct batadv_icmp_header *)skb->data;
 264
 265                 ether_addr_copy(icmph->dst, icmph->orig);
 266                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 267                 icmph->msg_type = BATADV_ECHO_REPLY;
 268                 icmph->ttl = BATADV_TTL;
 269
 270                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 271                 if (res != NET_XMIT_DROP)
 272                         ret = NET_RX_SUCCESS;
 273
 274                 break;
 275         default:
 276                 /* drop unknown type */
 277                 goto out;
 278         }
 279 out:
 280         if (primary_if)
 281                 batadv_hardif_put(primary_if);
 282         if (orig_node)
 283                 batadv_orig_node_put(orig_node);
 284         return ret;
 285 }
 286
 287 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 288                                          struct sk_buff *skb)
 289 {
 290         struct batadv_hard_iface *primary_if = NULL;
 291         struct batadv_orig_node *orig_node = NULL;
 292         struct batadv_icmp_packet *icmp_packet;
 293         int ret = NET_RX_DROP;
 294
 295         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 296
 297         /* send TTL exceeded if packet is an echo request (traceroute) */
 298         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 299                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 300                          icmp_packet->orig, icmp_packet->dst);
 301                 goto out;
 302         }
 303
 304         primary_if = batadv_primary_if_get_selected(bat_priv);
 305         if (!primary_if)
 306                 goto out;
 307
 308         /* get routing information */
 309         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 310         if (!orig_node)
 311                 goto out;
 312
 313         /* create a copy of the skb, if needed, to modify it. */
 314         if (skb_cow(skb, ETH_HLEN) < 0)
 315                 goto out;
 316
 317         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 318
 319         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 320         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 321         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 322         icmp_packet->ttl = BATADV_TTL;
 323
 324         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
 325                 ret = NET_RX_SUCCESS;
 326
 327 out:
 328         if (primary_if)
 329                 batadv_hardif_put(primary_if);
 330         if (orig_node)
 331                 batadv_orig_node_put(orig_node);
 332         return ret;
 333 }
 334
 335 int batadv_recv_icmp_packet(struct sk_buff *skb,
 336                             struct batadv_hard_iface *recv_if)
 337 {
 338         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 339         struct batadv_icmp_header *icmph;
 340         struct batadv_icmp_packet_rr *icmp_packet_rr;
 341         struct ethhdr *ethhdr;
 342         struct batadv_orig_node *orig_node = NULL;
 343         int hdr_size = sizeof(struct batadv_icmp_header);
 344         int ret = NET_RX_DROP;
 345
 346         /* drop packet if it has not necessary minimum size */
 347         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 348                 goto out;
 349
 350         ethhdr = eth_hdr(skb);
 351
 352         /* packet with unicast indication but broadcast recipient */
 353         if (is_broadcast_ether_addr(ethhdr->h_dest))
 354                 goto out;
 355
 356         /* packet with broadcast sender address */
 357         if (is_broadcast_ether_addr(ethhdr->h_source))
 358                 goto out;
 359
 360         /* not for me */
 361         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 362                 goto out;
 363
 364         icmph = (struct batadv_icmp_header *)skb->data;
 365
 366         /* add record route information if not full */
 367         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 368              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 369             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 370                 if (skb_linearize(skb) < 0)
 371                         goto out;
 372
 373                 /* create a copy of the skb, if needed, to modify it. */
 374                 if (skb_cow(skb, ETH_HLEN) < 0)
 375                         goto out;
 376
 377                 icmph = (struct batadv_icmp_header *)skb->data;
 378                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 379                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 380                         goto out;
 381
 382                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 383                                 ethhdr->h_dest);
 384                 icmp_packet_rr->rr_cur++;
 385         }
 386
 387         /* packet for me */
 388         if (batadv_is_my_mac(bat_priv, icmph->dst))
 389                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 390
 391         /* TTL exceeded */
 392         if (icmph->ttl < 2)
 393                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 394
 395         /* get routing information */
 396         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 397         if (!orig_node)
 398                 goto out;
 399
 400         /* create a copy of the skb, if needed, to modify it. */
 401         if (skb_cow(skb, ETH_HLEN) < 0)
 402                 goto out;
 403
 404         icmph = (struct batadv_icmp_header *)skb->data;
 405
 406         /* decrement ttl */
 407         icmph->ttl--;
 408
 409         /* route it */
 410         if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
 411                 ret = NET_RX_SUCCESS;
 412
 413 out:
 414         if (orig_node)
 415                 batadv_orig_node_put(orig_node);
 416         return ret;
 417 }
 418
 419 /**
 420  * batadv_check_unicast_packet - Check for malformed unicast packets
 421  * @bat_priv: the bat priv with all the soft interface information
 422  * @skb: packet to check
 423  * @hdr_size: size of header to pull
 424  *
 425  * Check for short header and bad addresses in given packet.
 426  *
 427  * Return: negative value when check fails and 0 otherwise. The negative value
 428  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 429  * destination or source, and -EREMOTE for non-local (other host) destination.
 430  */
 431 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 432                                        struct sk_buff *skb, int hdr_size)
 433 {
 434         struct ethhdr *ethhdr;
 435
 436         /* drop packet if it has not necessary minimum size */
 437         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 438                 return -ENODATA;
 439
 440         ethhdr = eth_hdr(skb);
 441
 442         /* packet with unicast indication but broadcast recipient */
 443         if (is_broadcast_ether_addr(ethhdr->h_dest))
 444                 return -EBADR;
 445
 446         /* packet with broadcast sender address */
 447         if (is_broadcast_ether_addr(ethhdr->h_source))
 448                 return -EBADR;
 449
 450         /* not for me */
 451         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 452                 return -EREMOTE;
 453
 454         return 0;
 455 }
 456
 457 /**
 458  * batadv_find_router - find a suitable router for this originator
 459  * @bat_priv: the bat priv with all the soft interface information
 460  * @orig_node: the destination node
 461  * @recv_if: pointer to interface this packet was received on
 462  *
 463  * Return: the router which should be used for this orig_node on
 464  * this interface, or NULL if not available.
 465  */
 466 struct batadv_neigh_node *
 467 batadv_find_router(struct batadv_priv *bat_priv,
 468                    struct batadv_orig_node *orig_node,
 469                    struct batadv_hard_iface *recv_if)
 470 {
 471         struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
 472         struct batadv_neigh_node *first_candidate_router = NULL;
 473         struct batadv_neigh_node *next_candidate_router = NULL;
 474         struct batadv_neigh_node *router, *cand_router = NULL;
 475         struct batadv_neigh_node *last_cand_router = NULL;
 476         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 477         struct batadv_orig_ifinfo *next_candidate = NULL;
 478         struct batadv_orig_ifinfo *last_candidate;
 479         bool last_candidate_found = false;
 480
 481         if (!orig_node)
 482                 return NULL;
 483
 484         router = batadv_orig_router_get(orig_node, recv_if);
 485
 486         if (!router)
 487                 return router;
 488
 489         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 490          * and if activated.
 491          */
 492         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 493                 return router;
 494
 495         /* bonding: loop through the list of possible routers found
 496          * for the various outgoing interfaces and find a candidate after
 497          * the last chosen bonding candidate (next_candidate). If no such
 498          * router is found, use the first candidate found (the previously
 499          * chosen bonding candidate might have been the last one in the list).
 500          * If this can't be found either, return the previously chosen
 501          * router - obviously there are no other candidates.
 502          */
 503         rcu_read_lock();
 504         last_candidate = orig_node->last_bonding_candidate;
 505         if (last_candidate)
 506                 last_cand_router = rcu_dereference(last_candidate->router);
 507
 508         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 509                 /* acquire some structures and references ... */
 510                 if (!kref_get_unless_zero(&cand->refcount))
 511                         continue;
 512
 513                 cand_router = rcu_dereference(cand->router);
 514                 if (!cand_router)
 515                         goto next;
 516
 517                 if (!kref_get_unless_zero(&cand_router->refcount)) {
 518                         cand_router = NULL;
 519                         goto next;
 520                 }
 521
 522                 /* alternative candidate should be good enough to be
 523                  * considered
 524                  */
 525                 if (!bao->bat_neigh_is_similar_or_better(cand_router,
 526                                                          cand->if_outgoing,
 527                                                          router, recv_if))
 528                         goto next;
 529
 530                 /* don't use the same router twice */
 531                 if (last_cand_router == cand_router)
 532                         goto next;
 533
 534                 /* mark the first possible candidate */
 535                 if (!first_candidate) {
 536                         kref_get(&cand_router->refcount);
 537                         kref_get(&cand->refcount);
 538                         first_candidate = cand;
 539                         first_candidate_router = cand_router;
 540                 }
 541
 542                 /* check if the loop has already passed the previously selected
 543                  * candidate ... this function should select the next candidate
 544                  * AFTER the previously used bonding candidate.
 545                  */
 546                 if (!last_candidate || last_candidate_found) {
 547                         next_candidate = cand;
 548                         next_candidate_router = cand_router;
 549                         break;
 550                 }
 551
 552                 if (last_candidate == cand)
 553                         last_candidate_found = true;
 554 next:
 555                 /* free references */
 556                 if (cand_router) {
 557                         batadv_neigh_node_put(cand_router);
 558                         cand_router = NULL;
 559                 }
 560                 batadv_orig_ifinfo_put(cand);
 561         }
 562         rcu_read_unlock();
 563
 564         /* last_bonding_candidate is reset below, remove the old reference. */
 565         if (orig_node->last_bonding_candidate)
 566                 batadv_orig_ifinfo_put(orig_node->last_bonding_candidate);
 567
 568         /* After finding candidates, handle the three cases:
 569          * 1) there is a next candidate, use that
 570          * 2) there is no next candidate, use the first of the list
 571          * 3) there is no candidate at all, return the default router
 572          */
 573         if (next_candidate) {
 574                 batadv_neigh_node_put(router);
 575
 576                 /* remove references to first candidate, we don't need it. */
 577                 if (first_candidate) {
 578                         batadv_neigh_node_put(first_candidate_router);
 579                         batadv_orig_ifinfo_put(first_candidate);
 580                 }
 581                 router = next_candidate_router;
 582                 orig_node->last_bonding_candidate = next_candidate;
 583         } else if (first_candidate) {
 584                 batadv_neigh_node_put(router);
 585
 586                 /* refcounting has already been done in the loop above. */
 587                 router = first_candidate_router;
 588                 orig_node->last_bonding_candidate = first_candidate;
 589         } else {
 590                 orig_node->last_bonding_candidate = NULL;
 591         }
 592
 593         return router;
 594 }
 595
 596 static int batadv_route_unicast_packet(struct sk_buff *skb,
 597                                        struct batadv_hard_iface *recv_if)
 598 {
 599         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 600         struct batadv_orig_node *orig_node = NULL;
 601         struct batadv_unicast_packet *unicast_packet;
 602         struct ethhdr *ethhdr = eth_hdr(skb);
 603         int res, hdr_len, ret = NET_RX_DROP;
 604
 605         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 606
 607         /* TTL exceeded */
 608         if (unicast_packet->ttl < 2) {
 609                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 610                          ethhdr->h_source, unicast_packet->dest);
 611                 goto out;
 612         }
 613
 614         /* get routing information */
 615         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 616
 617         if (!orig_node)
 618                 goto out;
 619
 620         /* create a copy of the skb, if needed, to modify it. */
 621         if (skb_cow(skb, ETH_HLEN) < 0)
 622                 goto out;
 623
 624         /* decrement ttl */
 625         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 626         unicast_packet->ttl--;
 627
 628         switch (unicast_packet->packet_type) {
 629         case BATADV_UNICAST_4ADDR:
 630                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 631                 break;
 632         case BATADV_UNICAST:
 633                 hdr_len = sizeof(struct batadv_unicast_packet);
 634                 break;
 635         default:
 636                 /* other packet types not supported - yet */
 637                 hdr_len = -1;
 638                 break;
 639         }
 640
 641         if (hdr_len > 0)
 642                 batadv_skb_set_priority(skb, hdr_len);
 643
 644         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 645
 646         /* translate transmit result into receive result */
 647         if (res == NET_XMIT_SUCCESS) {
 648                 /* skb was transmitted and consumed */
 649                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 650                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 651                                    skb->len + ETH_HLEN);
 652
 653                 ret = NET_RX_SUCCESS;
 654         } else if (res == NET_XMIT_POLICED) {
 655                 /* skb was buffered and consumed */
 656                 ret = NET_RX_SUCCESS;
 657         }
 658
 659 out:
 660         if (orig_node)
 661                 batadv_orig_node_put(orig_node);
 662         return ret;
 663 }
 664
 665 /**
 666  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 667  * @bat_priv: the bat priv with all the soft interface information
 668  * @unicast_packet: the unicast header to be updated
 669  * @dst_addr: the payload destination
 670  * @vid: VLAN identifier
 671  *
 672  * Search the translation table for dst_addr and update the unicast header with
 673  * the new corresponding information (originator address where the destination
 674  * client currently is and its known TTVN)
 675  *
 676  * Return: true if the packet header has been updated, false otherwise
 677  */
 678 static bool
 679 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 680                               struct batadv_unicast_packet *unicast_packet,
 681                               u8 *dst_addr, unsigned short vid)
 682 {
 683         struct batadv_orig_node *orig_node = NULL;
 684         struct batadv_hard_iface *primary_if = NULL;
 685         bool ret = false;
 686         u8 *orig_addr, orig_ttvn;
 687
 688         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 689                 primary_if = batadv_primary_if_get_selected(bat_priv);
 690                 if (!primary_if)
 691                         goto out;
 692                 orig_addr = primary_if->net_dev->dev_addr;
 693                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 694         } else {
 695                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 696                                                      vid);
 697                 if (!orig_node)
 698                         goto out;
 699
 700                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 701                         goto out;
 702
 703                 orig_addr = orig_node->orig;
 704                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 705         }
 706
 707         /* update the packet header */
 708         ether_addr_copy(unicast_packet->dest, orig_addr);
 709         unicast_packet->ttvn = orig_ttvn;
 710
 711         ret = true;
 712 out:
 713         if (primary_if)
 714                 batadv_hardif_put(primary_if);
 715         if (orig_node)
 716                 batadv_orig_node_put(orig_node);
 717
 718         return ret;
 719 }
 720
 721 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 722                                      struct sk_buff *skb, int hdr_len) {
 723         struct batadv_unicast_packet *unicast_packet;
 724         struct batadv_hard_iface *primary_if;
 725         struct batadv_orig_node *orig_node;
 726         u8 curr_ttvn, old_ttvn;
 727         struct ethhdr *ethhdr;
 728         unsigned short vid;
 729         int is_old_ttvn;
 730
 731         /* check if there is enough data before accessing it */
 732         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 733                 return 0;
 734
 735         /* create a copy of the skb (in case of for re-routing) to modify it. */
 736         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 737                 return 0;
 738
 739         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 740         vid = batadv_get_vid(skb, hdr_len);
 741         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 742
 743         /* check if the destination client was served by this node and it is now
 744          * roaming. In this case, it means that the node has got a ROAM_ADV
 745          * message and that it knows the new destination in the mesh to re-route
 746          * the packet to
 747          */
 748         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 749                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 750                                                   ethhdr->h_dest, vid))
 751                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 752                                                bat_priv,
 753                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 754                                                unicast_packet->dest,
 755                                                ethhdr->h_dest);
 756                 /* at this point the mesh destination should have been
 757                  * substituted with the originator address found in the global
 758                  * table. If not, let the packet go untouched anyway because
 759                  * there is nothing the node can do
 760                  */
 761                 return 1;
 762         }
 763
 764         /* retrieve the TTVN known by this node for the packet destination. This
 765          * value is used later to check if the node which sent (or re-routed
 766          * last time) the packet had an updated information or not
 767          */
 768         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 769         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 770                 orig_node = batadv_orig_hash_find(bat_priv,
 771                                                   unicast_packet->dest);
 772                 /* if it is not possible to find the orig_node representing the
 773                  * destination, the packet can immediately be dropped as it will
 774                  * not be possible to deliver it
 775                  */
 776                 if (!orig_node)
 777                         return 0;
 778
 779                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 780                 batadv_orig_node_put(orig_node);
 781         }
 782
 783         /* check if the TTVN contained in the packet is fresher than what the
 784          * node knows
 785          */
 786         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 787         if (!is_old_ttvn)
 788                 return 1;
 789
 790         old_ttvn = unicast_packet->ttvn;
 791         /* the packet was forged based on outdated network information. Its
 792          * destination can possibly be updated and forwarded towards the new
 793          * target host
 794          */
 795         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 796                                           ethhdr->h_dest, vid)) {
 797                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 798                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 799                                        unicast_packet->dest, ethhdr->h_dest,
 800                                        old_ttvn, curr_ttvn);
 801                 return 1;
 802         }
 803
 804         /* the packet has not been re-routed: either the destination is
 805          * currently served by this node or there is no destination at all and
 806          * it is possible to drop the packet
 807          */
 808         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 809                 return 0;
 810
 811         /* update the header in order to let the packet be delivered to this
 812          * node's soft interface
 813          */
 814         primary_if = batadv_primary_if_get_selected(bat_priv);
 815         if (!primary_if)
 816                 return 0;
 817
 818         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 819
 820         batadv_hardif_put(primary_if);
 821
 822         unicast_packet->ttvn = curr_ttvn;
 823
 824         return 1;
 825 }
 826
 827 /**
 828  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 829  *      are in the unicast number space but not yet known to the implementation
 830  * @skb: unicast tvlv packet to process
 831  * @recv_if: pointer to interface this packet was received on
 832  *
 833  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 834  * otherwise.
 835  */
 836 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 837                                          struct batadv_hard_iface *recv_if)
 838 {
 839         struct batadv_unicast_packet *unicast_packet;
 840         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 841         int check, hdr_size = sizeof(*unicast_packet);
 842
 843         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 844         if (check < 0)
 845                 return NET_RX_DROP;
 846
 847         /* we don't know about this type, drop it. */
 848         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 849         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 850                 return NET_RX_DROP;
 851
 852         return batadv_route_unicast_packet(skb, recv_if);
 853 }
 854
 855 int batadv_recv_unicast_packet(struct sk_buff *skb,
 856                                struct batadv_hard_iface *recv_if)
 857 {
 858         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 859         struct batadv_unicast_packet *unicast_packet;
 860         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 861         u8 *orig_addr;
 862         struct batadv_orig_node *orig_node = NULL;
 863         int check, hdr_size = sizeof(*unicast_packet);
 864         enum batadv_subtype subtype;
 865         bool is4addr;
 866
 867         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 868         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 869
 870         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 871         /* the caller function should have already pulled 2 bytes */
 872         if (is4addr)
 873                 hdr_size = sizeof(*unicast_4addr_packet);
 874
 875         /* function returns -EREMOTE for promiscuous packets */
 876         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 877
 878         /* Even though the packet is not for us, we might save it to use for
 879          * decoding a later received coded packet
 880          */
 881         if (check == -EREMOTE)
 882                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 883
 884         if (check < 0)
 885                 return NET_RX_DROP;
 886         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 887                 return NET_RX_DROP;
 888
 889         /* packet for me */
 890         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 891                 if (is4addr) {
 892                         subtype = unicast_4addr_packet->subtype;
 893                         batadv_dat_inc_counter(bat_priv, subtype);
 894
 895                         /* Only payload data should be considered for speedy
 896                          * join. For example, DAT also uses unicast 4addr
 897                          * types, but those packets should not be considered
 898                          * for speedy join, since the clients do not actually
 899                          * reside at the sending originator.
 900                          */
 901                         if (subtype == BATADV_P_DATA) {
 902                                 orig_addr = unicast_4addr_packet->src;
 903                                 orig_node = batadv_orig_hash_find(bat_priv,
 904                                                                   orig_addr);
 905                         }
 906                 }
 907
 908                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 909                                                           hdr_size))
 910                         goto rx_success;
 911                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 912                                                         hdr_size))
 913                         goto rx_success;
 914
 915                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 916                                     orig_node);
 917
 918 rx_success:
 919                 if (orig_node)
 920                         batadv_orig_node_put(orig_node);
 921
 922                 return NET_RX_SUCCESS;
 923         }
 924
 925         return batadv_route_unicast_packet(skb, recv_if);
 926 }
 927
 928 /**
 929  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 930  * @skb: unicast tvlv packet to process
 931  * @recv_if: pointer to interface this packet was received on
 932  *
 933  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 934  * otherwise.
 935  */
 936 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
 937                              struct batadv_hard_iface *recv_if)
 938 {
 939         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 940         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
 941         unsigned char *tvlv_buff;
 942         u16 tvlv_buff_len;
 943         int hdr_size = sizeof(*unicast_tvlv_packet);
 944         int ret = NET_RX_DROP;
 945
 946         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 947                 return NET_RX_DROP;
 948
 949         /* the header is likely to be modified while forwarding */
 950         if (skb_cow(skb, hdr_size) < 0)
 951                 return NET_RX_DROP;
 952
 953         /* packet needs to be linearized to access the tvlv content */
 954         if (skb_linearize(skb) < 0)
 955                 return NET_RX_DROP;
 956
 957         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
 958
 959         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
 960         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
 961
 962         if (tvlv_buff_len > skb->len - hdr_size)
 963                 return NET_RX_DROP;
 964
 965         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
 966                                              unicast_tvlv_packet->src,
 967                                              unicast_tvlv_packet->dst,
 968                                              tvlv_buff, tvlv_buff_len);
 969
 970         if (ret != NET_RX_SUCCESS)
 971                 ret = batadv_route_unicast_packet(skb, recv_if);
 972         else
 973                 consume_skb(skb);
 974
 975         return ret;
 976 }
 977
 978 /**
 979  * batadv_recv_frag_packet - process received fragment
 980  * @skb: the received fragment
 981  * @recv_if: interface that the skb is received on
 982  *
 983  * This function does one of the three following things: 1) Forward fragment, if
 984  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
 985  * lack further fragments; 3) Merge fragments, if we have all needed parts.
 986  *
 987  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
 988  */
 989 int batadv_recv_frag_packet(struct sk_buff *skb,
 990                             struct batadv_hard_iface *recv_if)
 991 {
 992         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 993         struct batadv_orig_node *orig_node_src = NULL;
 994         struct batadv_frag_packet *frag_packet;
 995         int ret = NET_RX_DROP;
 996
 997         if (batadv_check_unicast_packet(bat_priv, skb,
 998                                         sizeof(*frag_packet)) < 0)
 999                 goto out;
1000
1001         frag_packet = (struct batadv_frag_packet *)skb->data;
1002         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1003         if (!orig_node_src)
1004                 goto out;
1005
1006         /* Route the fragment if it is not for us and too big to be merged. */
1007         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1008             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1009                 ret = NET_RX_SUCCESS;
1010                 goto out;
1011         }
1012
1013         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1014         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1015
1016         /* Add fragment to buffer and merge if possible. */
1017         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1018                 goto out;
1019
1020         /* Deliver merged packet to the appropriate handler, if it was
1021          * merged
1022          */
1023         if (skb)
1024                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1025                                        &recv_if->batman_adv_ptype, NULL);
1026
1027         ret = NET_RX_SUCCESS;
1028
1029 out:
1030         if (orig_node_src)
1031                 batadv_orig_node_put(orig_node_src);
1032
1033         return ret;
1034 }
1035
1036 int batadv_recv_bcast_packet(struct sk_buff *skb,
1037                              struct batadv_hard_iface *recv_if)
1038 {
1039         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1040         struct batadv_orig_node *orig_node = NULL;
1041         struct batadv_bcast_packet *bcast_packet;
1042         struct ethhdr *ethhdr;
1043         int hdr_size = sizeof(*bcast_packet);
1044         int ret = NET_RX_DROP;
1045         s32 seq_diff;
1046         u32 seqno;
1047
1048         /* drop packet if it has not necessary minimum size */
1049         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1050                 goto out;
1051
1052         ethhdr = eth_hdr(skb);
1053
1054         /* packet with broadcast indication but unicast recipient */
1055         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1056                 goto out;
1057
1058         /* packet with broadcast sender address */
1059         if (is_broadcast_ether_addr(ethhdr->h_source))
1060                 goto out;
1061
1062         /* ignore broadcasts sent by myself */
1063         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1064                 goto out;
1065
1066         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1067
1068         /* ignore broadcasts originated by myself */
1069         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1070                 goto out;
1071
1072         if (bcast_packet->ttl < 2)
1073                 goto out;
1074
1075         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1076
1077         if (!orig_node)
1078                 goto out;
1079
1080         spin_lock_bh(&orig_node->bcast_seqno_lock);
1081
1082         seqno = ntohl(bcast_packet->seqno);
1083         /* check whether the packet is a duplicate */
1084         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1085                             seqno))
1086                 goto spin_unlock;
1087
1088         seq_diff = seqno - orig_node->last_bcast_seqno;
1089
1090         /* check whether the packet is old and the host just restarted. */
1091         if (batadv_window_protected(bat_priv, seq_diff,
1092                                     BATADV_BCAST_MAX_AGE,
1093                                     &orig_node->bcast_seqno_reset, NULL))
1094                 goto spin_unlock;
1095
1096         /* mark broadcast in flood history, update window position
1097          * if required.
1098          */
1099         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1100                 orig_node->last_bcast_seqno = seqno;
1101
1102         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1103
1104         /* check whether this has been sent by another originator before */
1105         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1106                 goto out;
1107
1108         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1109
1110         /* rebroadcast packet */
1111         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1112
1113         /* don't hand the broadcast up if it is from an originator
1114          * from the same backbone.
1115          */
1116         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1117                 goto out;
1118
1119         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1120                 goto rx_success;
1121         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1122                 goto rx_success;
1123
1124         /* broadcast for me */
1125         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1126                             orig_node);
1127
1128 rx_success:
1129         ret = NET_RX_SUCCESS;
1130         goto out;
1131
1132 spin_unlock:
1133         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1134 out:
1135         if (orig_node)
1136                 batadv_orig_node_put(orig_node);
1137         return ret;
1138 }