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 "log.h"
  44 #include "network-coding.h"
  45 #include "originator.h"
  46 #include "packet.h"
  47 #include "send.h"
  48 #include "soft-interface.h"
  49 #include "tp_meter.h"
  50 #include "translation-table.h"
  51 #include "tvlv.h"
  52
  53 static int batadv_route_unicast_packet(struct sk_buff *skb,
  54                                        struct batadv_hard_iface *recv_if);
  55
  56 /**
  57  * _batadv_update_route - set the router for this originator
  58  * @bat_priv: the bat priv with all the soft interface information
  59  * @orig_node: orig node which is to be configured
  60  * @recv_if: the receive interface for which this route is set
  61  * @neigh_node: neighbor which should be the next router
  62  *
  63  * This function does not perform any error checks
  64  */
  65 static void _batadv_update_route(struct batadv_priv *bat_priv,
  66                                  struct batadv_orig_node *orig_node,
  67                                  struct batadv_hard_iface *recv_if,
  68                                  struct batadv_neigh_node *neigh_node)
  69 {
  70         struct batadv_orig_ifinfo *orig_ifinfo;
  71         struct batadv_neigh_node *curr_router;
  72
  73         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
  74         if (!orig_ifinfo)
  75                 return;
  76
  77         rcu_read_lock();
  78         curr_router = rcu_dereference(orig_ifinfo->router);
  79         if (curr_router && !kref_get_unless_zero(&curr_router->refcount))
  80                 curr_router = NULL;
  81         rcu_read_unlock();
  82
  83         /* route deleted */
  84         if ((curr_router) && (!neigh_node)) {
  85                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  86                            "Deleting route towards: %pM\n", orig_node->orig);
  87                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
  88                                           "Deleted route towards originator");
  89
  90         /* route added */
  91         } else if ((!curr_router) && (neigh_node)) {
  92                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  93                            "Adding route towards: %pM (via %pM)\n",
  94                            orig_node->orig, neigh_node->addr);
  95         /* route changed */
  96         } else if (neigh_node && curr_router) {
  97                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
  98                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
  99                            orig_node->orig, neigh_node->addr,
 100                            curr_router->addr);
 101         }
 102
 103         if (curr_router)
 104                 batadv_neigh_node_put(curr_router);
 105
 106         spin_lock_bh(&orig_node->neigh_list_lock);
 107         /* curr_router used earlier may not be the current orig_ifinfo->router
 108          * anymore because it was dereferenced outside of the neigh_list_lock
 109          * protected region. After the new best neighbor has replace the current
 110          * best neighbor the reference counter needs to decrease. Consequently,
 111          * the code needs to ensure the curr_router variable contains a pointer
 112          * to the replaced best neighbor.
 113          */
 114         curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
 115
 116         /* increase refcount of new best neighbor */
 117         if (neigh_node)
 118                 kref_get(&neigh_node->refcount);
 119
 120         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
 121         spin_unlock_bh(&orig_node->neigh_list_lock);
 122         batadv_orig_ifinfo_put(orig_ifinfo);
 123
 124         /* decrease refcount of previous best neighbor */
 125         if (curr_router)
 126                 batadv_neigh_node_put(curr_router);
 127 }
 128
 129 /**
 130  * batadv_update_route - set the router for this originator
 131  * @bat_priv: the bat priv with all the soft interface information
 132  * @orig_node: orig node which is to be configured
 133  * @recv_if: the receive interface for which this route is set
 134  * @neigh_node: neighbor which should be the next router
 135  */
 136 void batadv_update_route(struct batadv_priv *bat_priv,
 137                          struct batadv_orig_node *orig_node,
 138                          struct batadv_hard_iface *recv_if,
 139                          struct batadv_neigh_node *neigh_node)
 140 {
 141         struct batadv_neigh_node *router = NULL;
 142
 143         if (!orig_node)
 144                 goto out;
 145
 146         router = batadv_orig_router_get(orig_node, recv_if);
 147
 148         if (router != neigh_node)
 149                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
 150
 151 out:
 152         if (router)
 153                 batadv_neigh_node_put(router);
 154 }
 155
 156 /**
 157  * batadv_window_protected - checks whether the host restarted and is in the
 158  *  protection time.
 159  * @bat_priv: the bat priv with all the soft interface information
 160  * @seq_num_diff: difference between the current/received sequence number and
 161  *  the last sequence number
 162  * @seq_old_max_diff: maximum age of sequence number not considered as restart
 163  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
 164  *  is detected
 165  * @protection_started: is set to true if the protection window was started,
 166  *   doesn't change otherwise.
 167  *
 168  * Return:
 169  *  false if the packet is to be accepted.
 170  *  true if the packet is to be ignored.
 171  */
 172 bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
 173                              s32 seq_old_max_diff, unsigned long *last_reset,
 174                              bool *protection_started)
 175 {
 176         if (seq_num_diff <= -seq_old_max_diff ||
 177             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
 178                 if (!batadv_has_timed_out(*last_reset,
 179                                           BATADV_RESET_PROTECTION_MS))
 180                         return true;
 181
 182                 *last_reset = jiffies;
 183                 if (protection_started)
 184                         *protection_started = true;
 185                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 186                            "old packet received, start protection\n");
 187         }
 188
 189         return false;
 190 }
 191
 192 bool batadv_check_management_packet(struct sk_buff *skb,
 193                                     struct batadv_hard_iface *hard_iface,
 194                                     int header_len)
 195 {
 196         struct ethhdr *ethhdr;
 197
 198         /* drop packet if it has not necessary minimum size */
 199         if (unlikely(!pskb_may_pull(skb, header_len)))
 200                 return false;
 201
 202         ethhdr = eth_hdr(skb);
 203
 204         /* packet with broadcast indication but unicast recipient */
 205         if (!is_broadcast_ether_addr(ethhdr->h_dest))
 206                 return false;
 207
 208         /* packet with broadcast sender address */
 209         if (is_broadcast_ether_addr(ethhdr->h_source))
 210                 return false;
 211
 212         /* create a copy of the skb, if needed, to modify it. */
 213         if (skb_cow(skb, 0) < 0)
 214                 return false;
 215
 216         /* keep skb linear */
 217         if (skb_linearize(skb) < 0)
 218                 return false;
 219
 220         return true;
 221 }
 222
 223 /**
 224  * batadv_recv_my_icmp_packet - receive an icmp packet locally
 225  * @bat_priv: the bat priv with all the soft interface information
 226  * @skb: icmp packet to process
 227  *
 228  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 229  * otherwise.
 230  */
 231 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
 232                                       struct sk_buff *skb)
 233 {
 234         struct batadv_hard_iface *primary_if = NULL;
 235         struct batadv_orig_node *orig_node = NULL;
 236         struct batadv_icmp_header *icmph;
 237         int res, ret = NET_RX_DROP;
 238
 239         icmph = (struct batadv_icmp_header *)skb->data;
 240
 241         switch (icmph->msg_type) {
 242         case BATADV_ECHO_REPLY:
 243         case BATADV_DESTINATION_UNREACHABLE:
 244         case BATADV_TTL_EXCEEDED:
 245                 /* receive the packet */
 246                 if (skb_linearize(skb) < 0)
 247                         break;
 248
 249                 batadv_socket_receive_packet(icmph, skb->len);
 250                 break;
 251         case BATADV_ECHO_REQUEST:
 252                 /* answer echo request (ping) */
 253                 primary_if = batadv_primary_if_get_selected(bat_priv);
 254                 if (!primary_if)
 255                         goto out;
 256
 257                 /* get routing information */
 258                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
 259                 if (!orig_node)
 260                         goto out;
 261
 262                 /* create a copy of the skb, if needed, to modify it. */
 263                 if (skb_cow(skb, ETH_HLEN) < 0)
 264                         goto out;
 265
 266                 icmph = (struct batadv_icmp_header *)skb->data;
 267
 268                 ether_addr_copy(icmph->dst, icmph->orig);
 269                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
 270                 icmph->msg_type = BATADV_ECHO_REPLY;
 271                 icmph->ttl = BATADV_TTL;
 272
 273                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 274                 if (res == -1)
 275                         goto out;
 276
 277                 ret = NET_RX_SUCCESS;
 278
 279                 break;
 280         case BATADV_TP:
 281                 if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet)))
 282                         goto out;
 283
 284                 batadv_tp_meter_recv(bat_priv, skb);
 285                 ret = NET_RX_SUCCESS;
 286                 goto out;
 287         default:
 288                 /* drop unknown type */
 289                 goto out;
 290         }
 291 out:
 292         if (primary_if)
 293                 batadv_hardif_put(primary_if);
 294         if (orig_node)
 295                 batadv_orig_node_put(orig_node);
 296         return ret;
 297 }
 298
 299 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
 300                                          struct sk_buff *skb)
 301 {
 302         struct batadv_hard_iface *primary_if = NULL;
 303         struct batadv_orig_node *orig_node = NULL;
 304         struct batadv_icmp_packet *icmp_packet;
 305         int res, ret = NET_RX_DROP;
 306
 307         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 308
 309         /* send TTL exceeded if packet is an echo request (traceroute) */
 310         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 311                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
 312                          icmp_packet->orig, icmp_packet->dst);
 313                 goto out;
 314         }
 315
 316         primary_if = batadv_primary_if_get_selected(bat_priv);
 317         if (!primary_if)
 318                 goto out;
 319
 320         /* get routing information */
 321         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
 322         if (!orig_node)
 323                 goto out;
 324
 325         /* create a copy of the skb, if needed, to modify it. */
 326         if (skb_cow(skb, ETH_HLEN) < 0)
 327                 goto out;
 328
 329         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 330
 331         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
 332         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
 333         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
 334         icmp_packet->ttl = BATADV_TTL;
 335
 336         res = batadv_send_skb_to_orig(skb, orig_node, NULL);
 337         if (res != -1)
 338                 ret = NET_RX_SUCCESS;
 339
 340 out:
 341         if (primary_if)
 342                 batadv_hardif_put(primary_if);
 343         if (orig_node)
 344                 batadv_orig_node_put(orig_node);
 345         return ret;
 346 }
 347
 348 int batadv_recv_icmp_packet(struct sk_buff *skb,
 349                             struct batadv_hard_iface *recv_if)
 350 {
 351         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 352         struct batadv_icmp_header *icmph;
 353         struct batadv_icmp_packet_rr *icmp_packet_rr;
 354         struct ethhdr *ethhdr;
 355         struct batadv_orig_node *orig_node = NULL;
 356         int hdr_size = sizeof(struct batadv_icmp_header);
 357         int res, ret = NET_RX_DROP;
 358
 359         /* drop packet if it has not necessary minimum size */
 360         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 361                 goto out;
 362
 363         ethhdr = eth_hdr(skb);
 364
 365         /* packet with unicast indication but broadcast recipient */
 366         if (is_broadcast_ether_addr(ethhdr->h_dest))
 367                 goto out;
 368
 369         /* packet with broadcast sender address */
 370         if (is_broadcast_ether_addr(ethhdr->h_source))
 371                 goto out;
 372
 373         /* not for me */
 374         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 375                 goto out;
 376
 377         icmph = (struct batadv_icmp_header *)skb->data;
 378
 379         /* add record route information if not full */
 380         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
 381              icmph->msg_type == BATADV_ECHO_REQUEST) &&
 382             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
 383                 if (skb_linearize(skb) < 0)
 384                         goto out;
 385
 386                 /* create a copy of the skb, if needed, to modify it. */
 387                 if (skb_cow(skb, ETH_HLEN) < 0)
 388                         goto out;
 389
 390                 ethhdr = eth_hdr(skb);
 391                 icmph = (struct batadv_icmp_header *)skb->data;
 392                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
 393                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
 394                         goto out;
 395
 396                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
 397                                 ethhdr->h_dest);
 398                 icmp_packet_rr->rr_cur++;
 399         }
 400
 401         /* packet for me */
 402         if (batadv_is_my_mac(bat_priv, icmph->dst))
 403                 return batadv_recv_my_icmp_packet(bat_priv, skb);
 404
 405         /* TTL exceeded */
 406         if (icmph->ttl < 2)
 407                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
 408
 409         /* get routing information */
 410         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
 411         if (!orig_node)
 412                 goto out;
 413
 414         /* create a copy of the skb, if needed, to modify it. */
 415         if (skb_cow(skb, ETH_HLEN) < 0)
 416                 goto out;
 417
 418         icmph = (struct batadv_icmp_header *)skb->data;
 419
 420         /* decrement ttl */
 421         icmph->ttl--;
 422
 423         /* route it */
 424         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 425         if (res != -1)
 426                 ret = NET_RX_SUCCESS;
 427
 428 out:
 429         if (orig_node)
 430                 batadv_orig_node_put(orig_node);
 431         return ret;
 432 }
 433
 434 /**
 435  * batadv_check_unicast_packet - Check for malformed unicast packets
 436  * @bat_priv: the bat priv with all the soft interface information
 437  * @skb: packet to check
 438  * @hdr_size: size of header to pull
 439  *
 440  * Check for short header and bad addresses in given packet.
 441  *
 442  * Return: negative value when check fails and 0 otherwise. The negative value
 443  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
 444  * destination or source, and -EREMOTE for non-local (other host) destination.
 445  */
 446 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
 447                                        struct sk_buff *skb, int hdr_size)
 448 {
 449         struct ethhdr *ethhdr;
 450
 451         /* drop packet if it has not necessary minimum size */
 452         if (unlikely(!pskb_may_pull(skb, hdr_size)))
 453                 return -ENODATA;
 454
 455         ethhdr = eth_hdr(skb);
 456
 457         /* packet with unicast indication but broadcast recipient */
 458         if (is_broadcast_ether_addr(ethhdr->h_dest))
 459                 return -EBADR;
 460
 461         /* packet with broadcast sender address */
 462         if (is_broadcast_ether_addr(ethhdr->h_source))
 463                 return -EBADR;
 464
 465         /* not for me */
 466         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
 467                 return -EREMOTE;
 468
 469         return 0;
 470 }
 471
 472 /**
 473  * batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
 474  * @orig_node: originator node whose bonding candidates should be replaced
 475  * @new_candidate: new bonding candidate or NULL
 476  */
 477 static void
 478 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
 479                             struct batadv_orig_ifinfo *new_candidate)
 480 {
 481         struct batadv_orig_ifinfo *old_candidate;
 482
 483         spin_lock_bh(&orig_node->neigh_list_lock);
 484         old_candidate = orig_node->last_bonding_candidate;
 485
 486         if (new_candidate)
 487                 kref_get(&new_candidate->refcount);
 488         orig_node->last_bonding_candidate = new_candidate;
 489         spin_unlock_bh(&orig_node->neigh_list_lock);
 490
 491         if (old_candidate)
 492                 batadv_orig_ifinfo_put(old_candidate);
 493 }
 494
 495 /**
 496  * batadv_find_router - find a suitable router for this originator
 497  * @bat_priv: the bat priv with all the soft interface information
 498  * @orig_node: the destination node
 499  * @recv_if: pointer to interface this packet was received on
 500  *
 501  * Return: the router which should be used for this orig_node on
 502  * this interface, or NULL if not available.
 503  */
 504 struct batadv_neigh_node *
 505 batadv_find_router(struct batadv_priv *bat_priv,
 506                    struct batadv_orig_node *orig_node,
 507                    struct batadv_hard_iface *recv_if)
 508 {
 509         struct batadv_algo_ops *bao = bat_priv->algo_ops;
 510         struct batadv_neigh_node *first_candidate_router = NULL;
 511         struct batadv_neigh_node *next_candidate_router = NULL;
 512         struct batadv_neigh_node *router, *cand_router = NULL;
 513         struct batadv_neigh_node *last_cand_router = NULL;
 514         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
 515         struct batadv_orig_ifinfo *next_candidate = NULL;
 516         struct batadv_orig_ifinfo *last_candidate;
 517         bool last_candidate_found = false;
 518
 519         if (!orig_node)
 520                 return NULL;
 521
 522         router = batadv_orig_router_get(orig_node, recv_if);
 523
 524         if (!router)
 525                 return router;
 526
 527         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
 528          * and if activated.
 529          */
 530         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
 531                 return router;
 532
 533         /* bonding: loop through the list of possible routers found
 534          * for the various outgoing interfaces and find a candidate after
 535          * the last chosen bonding candidate (next_candidate). If no such
 536          * router is found, use the first candidate found (the previously
 537          * chosen bonding candidate might have been the last one in the list).
 538          * If this can't be found either, return the previously chosen
 539          * router - obviously there are no other candidates.
 540          */
 541         rcu_read_lock();
 542         last_candidate = orig_node->last_bonding_candidate;
 543         if (last_candidate)
 544                 last_cand_router = rcu_dereference(last_candidate->router);
 545
 546         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
 547                 /* acquire some structures and references ... */
 548                 if (!kref_get_unless_zero(&cand->refcount))
 549                         continue;
 550
 551                 cand_router = rcu_dereference(cand->router);
 552                 if (!cand_router)
 553                         goto next;
 554
 555                 if (!kref_get_unless_zero(&cand_router->refcount)) {
 556                         cand_router = NULL;
 557                         goto next;
 558                 }
 559
 560                 /* alternative candidate should be good enough to be
 561                  * considered
 562                  */
 563                 if (!bao->neigh.is_similar_or_better(cand_router,
 564                                                      cand->if_outgoing, router,
 565                                                      recv_if))
 566                         goto next;
 567
 568                 /* don't use the same router twice */
 569                 if (last_cand_router == cand_router)
 570                         goto next;
 571
 572                 /* mark the first possible candidate */
 573                 if (!first_candidate) {
 574                         kref_get(&cand_router->refcount);
 575                         kref_get(&cand->refcount);
 576                         first_candidate = cand;
 577                         first_candidate_router = cand_router;
 578                 }
 579
 580                 /* check if the loop has already passed the previously selected
 581                  * candidate ... this function should select the next candidate
 582                  * AFTER the previously used bonding candidate.
 583                  */
 584                 if (!last_candidate || last_candidate_found) {
 585                         next_candidate = cand;
 586                         next_candidate_router = cand_router;
 587                         break;
 588                 }
 589
 590                 if (last_candidate == cand)
 591                         last_candidate_found = true;
 592 next:
 593                 /* free references */
 594                 if (cand_router) {
 595                         batadv_neigh_node_put(cand_router);
 596                         cand_router = NULL;
 597                 }
 598                 batadv_orig_ifinfo_put(cand);
 599         }
 600         rcu_read_unlock();
 601
 602         /* After finding candidates, handle the three cases:
 603          * 1) there is a next candidate, use that
 604          * 2) there is no next candidate, use the first of the list
 605          * 3) there is no candidate at all, return the default router
 606          */
 607         if (next_candidate) {
 608                 batadv_neigh_node_put(router);
 609
 610                 kref_get(&next_candidate_router->refcount);
 611                 router = next_candidate_router;
 612                 batadv_last_bonding_replace(orig_node, next_candidate);
 613         } else if (first_candidate) {
 614                 batadv_neigh_node_put(router);
 615
 616                 kref_get(&first_candidate_router->refcount);
 617                 router = first_candidate_router;
 618                 batadv_last_bonding_replace(orig_node, first_candidate);
 619         } else {
 620                 batadv_last_bonding_replace(orig_node, NULL);
 621         }
 622
 623         /* cleanup of candidates */
 624         if (first_candidate) {
 625                 batadv_neigh_node_put(first_candidate_router);
 626                 batadv_orig_ifinfo_put(first_candidate);
 627         }
 628
 629         if (next_candidate) {
 630                 batadv_neigh_node_put(next_candidate_router);
 631                 batadv_orig_ifinfo_put(next_candidate);
 632         }
 633
 634         return router;
 635 }
 636
 637 static int batadv_route_unicast_packet(struct sk_buff *skb,
 638                                        struct batadv_hard_iface *recv_if)
 639 {
 640         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 641         struct batadv_orig_node *orig_node = NULL;
 642         struct batadv_unicast_packet *unicast_packet;
 643         struct ethhdr *ethhdr = eth_hdr(skb);
 644         int res, hdr_len, ret = NET_RX_DROP;
 645         unsigned int len;
 646
 647         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 648
 649         /* TTL exceeded */
 650         if (unicast_packet->ttl < 2) {
 651                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
 652                          ethhdr->h_source, unicast_packet->dest);
 653                 goto out;
 654         }
 655
 656         /* get routing information */
 657         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
 658
 659         if (!orig_node)
 660                 goto out;
 661
 662         /* create a copy of the skb, if needed, to modify it. */
 663         if (skb_cow(skb, ETH_HLEN) < 0)
 664                 goto out;
 665
 666         /* decrement ttl */
 667         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 668         unicast_packet->ttl--;
 669
 670         switch (unicast_packet->packet_type) {
 671         case BATADV_UNICAST_4ADDR:
 672                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
 673                 break;
 674         case BATADV_UNICAST:
 675                 hdr_len = sizeof(struct batadv_unicast_packet);
 676                 break;
 677         default:
 678                 /* other packet types not supported - yet */
 679                 hdr_len = -1;
 680                 break;
 681         }
 682
 683         if (hdr_len > 0)
 684                 batadv_skb_set_priority(skb, hdr_len);
 685
 686         len = skb->len;
 687         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 688         if (res == -1)
 689                 goto out;
 690
 691         /* translate transmit result into receive result */
 692         if (res == NET_XMIT_SUCCESS) {
 693                 /* skb was transmitted and consumed */
 694                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 695                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 696                                    len + ETH_HLEN);
 697         }
 698
 699         ret = NET_RX_SUCCESS;
 700
 701 out:
 702         if (orig_node)
 703                 batadv_orig_node_put(orig_node);
 704         return ret;
 705 }
 706
 707 /**
 708  * batadv_reroute_unicast_packet - update the unicast header for re-routing
 709  * @bat_priv: the bat priv with all the soft interface information
 710  * @unicast_packet: the unicast header to be updated
 711  * @dst_addr: the payload destination
 712  * @vid: VLAN identifier
 713  *
 714  * Search the translation table for dst_addr and update the unicast header with
 715  * the new corresponding information (originator address where the destination
 716  * client currently is and its known TTVN)
 717  *
 718  * Return: true if the packet header has been updated, false otherwise
 719  */
 720 static bool
 721 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
 722                               struct batadv_unicast_packet *unicast_packet,
 723                               u8 *dst_addr, unsigned short vid)
 724 {
 725         struct batadv_orig_node *orig_node = NULL;
 726         struct batadv_hard_iface *primary_if = NULL;
 727         bool ret = false;
 728         u8 *orig_addr, orig_ttvn;
 729
 730         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
 731                 primary_if = batadv_primary_if_get_selected(bat_priv);
 732                 if (!primary_if)
 733                         goto out;
 734                 orig_addr = primary_if->net_dev->dev_addr;
 735                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 736         } else {
 737                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
 738                                                      vid);
 739                 if (!orig_node)
 740                         goto out;
 741
 742                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
 743                         goto out;
 744
 745                 orig_addr = orig_node->orig;
 746                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 747         }
 748
 749         /* update the packet header */
 750         ether_addr_copy(unicast_packet->dest, orig_addr);
 751         unicast_packet->ttvn = orig_ttvn;
 752
 753         ret = true;
 754 out:
 755         if (primary_if)
 756                 batadv_hardif_put(primary_if);
 757         if (orig_node)
 758                 batadv_orig_node_put(orig_node);
 759
 760         return ret;
 761 }
 762
 763 static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 764                                       struct sk_buff *skb, int hdr_len)
 765 {
 766         struct batadv_unicast_packet *unicast_packet;
 767         struct batadv_hard_iface *primary_if;
 768         struct batadv_orig_node *orig_node;
 769         u8 curr_ttvn, old_ttvn;
 770         struct ethhdr *ethhdr;
 771         unsigned short vid;
 772         int is_old_ttvn;
 773
 774         /* check if there is enough data before accessing it */
 775         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
 776                 return false;
 777
 778         /* create a copy of the skb (in case of for re-routing) to modify it. */
 779         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
 780                 return false;
 781
 782         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 783         vid = batadv_get_vid(skb, hdr_len);
 784         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
 785
 786         /* check if the destination client was served by this node and it is now
 787          * roaming. In this case, it means that the node has got a ROAM_ADV
 788          * message and that it knows the new destination in the mesh to re-route
 789          * the packet to
 790          */
 791         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
 792                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 793                                                   ethhdr->h_dest, vid))
 794                         batadv_dbg_ratelimited(BATADV_DBG_TT,
 795                                                bat_priv,
 796                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
 797                                                unicast_packet->dest,
 798                                                ethhdr->h_dest);
 799                 /* at this point the mesh destination should have been
 800                  * substituted with the originator address found in the global
 801                  * table. If not, let the packet go untouched anyway because
 802                  * there is nothing the node can do
 803                  */
 804                 return true;
 805         }
 806
 807         /* retrieve the TTVN known by this node for the packet destination. This
 808          * value is used later to check if the node which sent (or re-routed
 809          * last time) the packet had an updated information or not
 810          */
 811         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
 812         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 813                 orig_node = batadv_orig_hash_find(bat_priv,
 814                                                   unicast_packet->dest);
 815                 /* if it is not possible to find the orig_node representing the
 816                  * destination, the packet can immediately be dropped as it will
 817                  * not be possible to deliver it
 818                  */
 819                 if (!orig_node)
 820                         return false;
 821
 822                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
 823                 batadv_orig_node_put(orig_node);
 824         }
 825
 826         /* check if the TTVN contained in the packet is fresher than what the
 827          * node knows
 828          */
 829         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
 830         if (!is_old_ttvn)
 831                 return true;
 832
 833         old_ttvn = unicast_packet->ttvn;
 834         /* the packet was forged based on outdated network information. Its
 835          * destination can possibly be updated and forwarded towards the new
 836          * target host
 837          */
 838         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
 839                                           ethhdr->h_dest, vid)) {
 840                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
 841                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
 842                                        unicast_packet->dest, ethhdr->h_dest,
 843                                        old_ttvn, curr_ttvn);
 844                 return true;
 845         }
 846
 847         /* the packet has not been re-routed: either the destination is
 848          * currently served by this node or there is no destination at all and
 849          * it is possible to drop the packet
 850          */
 851         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
 852                 return false;
 853
 854         /* update the header in order to let the packet be delivered to this
 855          * node's soft interface
 856          */
 857         primary_if = batadv_primary_if_get_selected(bat_priv);
 858         if (!primary_if)
 859                 return false;
 860
 861         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
 862
 863         batadv_hardif_put(primary_if);
 864
 865         unicast_packet->ttvn = curr_ttvn;
 866
 867         return true;
 868 }
 869
 870 /**
 871  * batadv_recv_unhandled_unicast_packet - receive and process packets which
 872  *      are in the unicast number space but not yet known to the implementation
 873  * @skb: unicast tvlv packet to process
 874  * @recv_if: pointer to interface this packet was received on
 875  *
 876  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 877  * otherwise.
 878  */
 879 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
 880                                          struct batadv_hard_iface *recv_if)
 881 {
 882         struct batadv_unicast_packet *unicast_packet;
 883         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 884         int check, hdr_size = sizeof(*unicast_packet);
 885
 886         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 887         if (check < 0)
 888                 return NET_RX_DROP;
 889
 890         /* we don't know about this type, drop it. */
 891         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 892         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
 893                 return NET_RX_DROP;
 894
 895         return batadv_route_unicast_packet(skb, recv_if);
 896 }
 897
 898 int batadv_recv_unicast_packet(struct sk_buff *skb,
 899                                struct batadv_hard_iface *recv_if)
 900 {
 901         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 902         struct batadv_unicast_packet *unicast_packet;
 903         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
 904         u8 *orig_addr;
 905         struct batadv_orig_node *orig_node = NULL;
 906         int check, hdr_size = sizeof(*unicast_packet);
 907         enum batadv_subtype subtype;
 908         bool is4addr;
 909
 910         unicast_packet = (struct batadv_unicast_packet *)skb->data;
 911         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 912
 913         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
 914         /* the caller function should have already pulled 2 bytes */
 915         if (is4addr)
 916                 hdr_size = sizeof(*unicast_4addr_packet);
 917
 918         /* function returns -EREMOTE for promiscuous packets */
 919         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
 920
 921         /* Even though the packet is not for us, we might save it to use for
 922          * decoding a later received coded packet
 923          */
 924         if (check == -EREMOTE)
 925                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
 926
 927         if (check < 0)
 928                 return NET_RX_DROP;
 929         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
 930                 return NET_RX_DROP;
 931
 932         /* packet for me */
 933         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
 934                 if (is4addr) {
 935                         subtype = unicast_4addr_packet->subtype;
 936                         batadv_dat_inc_counter(bat_priv, subtype);
 937
 938                         /* Only payload data should be considered for speedy
 939                          * join. For example, DAT also uses unicast 4addr
 940                          * types, but those packets should not be considered
 941                          * for speedy join, since the clients do not actually
 942                          * reside at the sending originator.
 943                          */
 944                         if (subtype == BATADV_P_DATA) {
 945                                 orig_addr = unicast_4addr_packet->src;
 946                                 orig_node = batadv_orig_hash_find(bat_priv,
 947                                                                   orig_addr);
 948                         }
 949                 }
 950
 951                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
 952                                                           hdr_size))
 953                         goto rx_success;
 954                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
 955                                                         hdr_size))
 956                         goto rx_success;
 957
 958                 batadv_interface_rx(recv_if->soft_iface, skb, hdr_size,
 959                                     orig_node);
 960
 961 rx_success:
 962                 if (orig_node)
 963                         batadv_orig_node_put(orig_node);
 964
 965                 return NET_RX_SUCCESS;
 966         }
 967
 968         return batadv_route_unicast_packet(skb, recv_if);
 969 }
 970
 971 /**
 972  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
 973  * @skb: unicast tvlv packet to process
 974  * @recv_if: pointer to interface this packet was received on
 975  *
 976  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
 977  * otherwise.
 978  */
 979 int batadv_recv_unicast_tvlv(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_unicast_tvlv_packet *unicast_tvlv_packet;
 984         unsigned char *tvlv_buff;
 985         u16 tvlv_buff_len;
 986         int hdr_size = sizeof(*unicast_tvlv_packet);
 987         int ret = NET_RX_DROP;
 988
 989         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
 990                 return NET_RX_DROP;
 991
 992         /* the header is likely to be modified while forwarding */
 993         if (skb_cow(skb, hdr_size) < 0)
 994                 return NET_RX_DROP;
 995
 996         /* packet needs to be linearized to access the tvlv content */
 997         if (skb_linearize(skb) < 0)
 998                 return NET_RX_DROP;
 999
1000         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1001
1002         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1003         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1004
1005         if (tvlv_buff_len > skb->len - hdr_size)
1006                 return NET_RX_DROP;
1007
1008         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1009                                              unicast_tvlv_packet->src,
1010                                              unicast_tvlv_packet->dst,
1011                                              tvlv_buff, tvlv_buff_len);
1012
1013         if (ret != NET_RX_SUCCESS)
1014                 ret = batadv_route_unicast_packet(skb, recv_if);
1015         else
1016                 consume_skb(skb);
1017
1018         return ret;
1019 }
1020
1021 /**
1022  * batadv_recv_frag_packet - process received fragment
1023  * @skb: the received fragment
1024  * @recv_if: interface that the skb is received on
1025  *
1026  * This function does one of the three following things: 1) Forward fragment, if
1027  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1028  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1029  *
1030  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1031  */
1032 int batadv_recv_frag_packet(struct sk_buff *skb,
1033                             struct batadv_hard_iface *recv_if)
1034 {
1035         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1036         struct batadv_orig_node *orig_node_src = NULL;
1037         struct batadv_frag_packet *frag_packet;
1038         int ret = NET_RX_DROP;
1039
1040         if (batadv_check_unicast_packet(bat_priv, skb,
1041                                         sizeof(*frag_packet)) < 0)
1042                 goto out;
1043
1044         frag_packet = (struct batadv_frag_packet *)skb->data;
1045         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1046         if (!orig_node_src)
1047                 goto out;
1048
1049         skb->priority = frag_packet->priority + 256;
1050
1051         /* Route the fragment if it is not for us and too big to be merged. */
1052         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1053             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1054                 ret = NET_RX_SUCCESS;
1055                 goto out;
1056         }
1057
1058         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1059         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1060
1061         /* Add fragment to buffer and merge if possible. */
1062         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1063                 goto out;
1064
1065         /* Deliver merged packet to the appropriate handler, if it was
1066          * merged
1067          */
1068         if (skb)
1069                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1070                                        &recv_if->batman_adv_ptype, NULL);
1071
1072         ret = NET_RX_SUCCESS;
1073
1074 out:
1075         if (orig_node_src)
1076                 batadv_orig_node_put(orig_node_src);
1077
1078         return ret;
1079 }
1080
1081 int batadv_recv_bcast_packet(struct sk_buff *skb,
1082                              struct batadv_hard_iface *recv_if)
1083 {
1084         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1085         struct batadv_orig_node *orig_node = NULL;
1086         struct batadv_bcast_packet *bcast_packet;
1087         struct ethhdr *ethhdr;
1088         int hdr_size = sizeof(*bcast_packet);
1089         int ret = NET_RX_DROP;
1090         s32 seq_diff;
1091         u32 seqno;
1092
1093         /* drop packet if it has not necessary minimum size */
1094         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1095                 goto out;
1096
1097         ethhdr = eth_hdr(skb);
1098
1099         /* packet with broadcast indication but unicast recipient */
1100         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1101                 goto out;
1102
1103         /* packet with broadcast sender address */
1104         if (is_broadcast_ether_addr(ethhdr->h_source))
1105                 goto out;
1106
1107         /* ignore broadcasts sent by myself */
1108         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1109                 goto out;
1110
1111         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1112
1113         /* ignore broadcasts originated by myself */
1114         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1115                 goto out;
1116
1117         if (bcast_packet->ttl < 2)
1118                 goto out;
1119
1120         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1121
1122         if (!orig_node)
1123                 goto out;
1124
1125         spin_lock_bh(&orig_node->bcast_seqno_lock);
1126
1127         seqno = ntohl(bcast_packet->seqno);
1128         /* check whether the packet is a duplicate */
1129         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1130                             seqno))
1131                 goto spin_unlock;
1132
1133         seq_diff = seqno - orig_node->last_bcast_seqno;
1134
1135         /* check whether the packet is old and the host just restarted. */
1136         if (batadv_window_protected(bat_priv, seq_diff,
1137                                     BATADV_BCAST_MAX_AGE,
1138                                     &orig_node->bcast_seqno_reset, NULL))
1139                 goto spin_unlock;
1140
1141         /* mark broadcast in flood history, update window position
1142          * if required.
1143          */
1144         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1145                 orig_node->last_bcast_seqno = seqno;
1146
1147         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1148
1149         /* check whether this has been sent by another originator before */
1150         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1151                 goto out;
1152
1153         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1154
1155         /* rebroadcast packet */
1156         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1157
1158         /* don't hand the broadcast up if it is from an originator
1159          * from the same backbone.
1160          */
1161         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1162                 goto out;
1163
1164         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1165                 goto rx_success;
1166         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1167                 goto rx_success;
1168
1169         /* broadcast for me */
1170         batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node);
1171
1172 rx_success:
1173         ret = NET_RX_SUCCESS;
1174         goto out;
1175
1176 spin_unlock:
1177         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1178 out:
1179         if (orig_node)
1180                 batadv_orig_node_put(orig_node);
1181         return ret;
1182 }