net/batman-adv/gateway_client.c

   1 /* Copyright (C) 2009-2012 B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner
   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, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include "bat_sysfs.h"
  22 #include "gateway_client.h"
  23 #include "gateway_common.h"
  24 #include "hard-interface.h"
  25 #include "originator.h"
  26 #include "translation-table.h"
  27 #include "routing.h"
  28 #include <linux/ip.h>
  29 #include <linux/ipv6.h>
  30 #include <linux/udp.h>
  31 #include <linux/if_vlan.h>
  32
  33 /* This is the offset of the options field in a dhcp packet starting at
  34  * the beginning of the dhcp header
  35  */
  36 #define BATADV_DHCP_OPTIONS_OFFSET 240
  37 #define BATADV_DHCP_REQUEST 3
  38
  39 static void batadv_gw_node_free_ref(struct gw_node *gw_node)
  40 {
  41         if (atomic_dec_and_test(&gw_node->refcount))
  42                 kfree_rcu(gw_node, rcu);
  43 }
  44
  45 static struct gw_node *batadv_gw_get_selected_gw_node(struct bat_priv *bat_priv)
  46 {
  47         struct gw_node *gw_node;
  48
  49         rcu_read_lock();
  50         gw_node = rcu_dereference(bat_priv->curr_gw);
  51         if (!gw_node)
  52                 goto out;
  53
  54         if (!atomic_inc_not_zero(&gw_node->refcount))
  55                 gw_node = NULL;
  56
  57 out:
  58         rcu_read_unlock();
  59         return gw_node;
  60 }
  61
  62 struct orig_node *batadv_gw_get_selected_orig(struct bat_priv *bat_priv)
  63 {
  64         struct gw_node *gw_node;
  65         struct orig_node *orig_node = NULL;
  66
  67         gw_node = batadv_gw_get_selected_gw_node(bat_priv);
  68         if (!gw_node)
  69                 goto out;
  70
  71         rcu_read_lock();
  72         orig_node = gw_node->orig_node;
  73         if (!orig_node)
  74                 goto unlock;
  75
  76         if (!atomic_inc_not_zero(&orig_node->refcount))
  77                 orig_node = NULL;
  78
  79 unlock:
  80         rcu_read_unlock();
  81 out:
  82         if (gw_node)
  83                 batadv_gw_node_free_ref(gw_node);
  84         return orig_node;
  85 }
  86
  87 static void batadv_gw_select(struct bat_priv *bat_priv,
  88                              struct gw_node *new_gw_node)
  89 {
  90         struct gw_node *curr_gw_node;
  91
  92         spin_lock_bh(&bat_priv->gw_list_lock);
  93
  94         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
  95                 new_gw_node = NULL;
  96
  97         curr_gw_node = rcu_dereference_protected(bat_priv->curr_gw, 1);
  98         rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
  99
 100         if (curr_gw_node)
 101                 batadv_gw_node_free_ref(curr_gw_node);
 102
 103         spin_unlock_bh(&bat_priv->gw_list_lock);
 104 }
 105
 106 void batadv_gw_deselect(struct bat_priv *bat_priv)
 107 {
 108         atomic_set(&bat_priv->gw_reselect, 1);
 109 }
 110
 111 static struct gw_node *batadv_gw_get_best_gw_node(struct bat_priv *bat_priv)
 112 {
 113         struct neigh_node *router;
 114         struct hlist_node *node;
 115         struct gw_node *gw_node, *curr_gw = NULL;
 116         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 117         uint8_t max_tq = 0;
 118         int down, up;
 119         struct orig_node *orig_node;
 120
 121         rcu_read_lock();
 122         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 123                 if (gw_node->deleted)
 124                         continue;
 125
 126                 orig_node = gw_node->orig_node;
 127                 router = batadv_orig_node_get_router(orig_node);
 128                 if (!router)
 129                         continue;
 130
 131                 if (!atomic_inc_not_zero(&gw_node->refcount))
 132                         goto next;
 133
 134                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 135                 case 1: /* fast connection */
 136                         batadv_gw_bandwidth_to_kbit(orig_node->gw_flags,
 137                                                     &down, &up);
 138
 139                         tmp_gw_factor = (router->tq_avg * router->tq_avg *
 140                                          down * 100 * 100) /
 141                                          (BATADV_TQ_LOCAL_WINDOW_SIZE *
 142                                           BATADV_TQ_LOCAL_WINDOW_SIZE * 64);
 143
 144                         if ((tmp_gw_factor > max_gw_factor) ||
 145                             ((tmp_gw_factor == max_gw_factor) &&
 146                              (router->tq_avg > max_tq))) {
 147                                 if (curr_gw)
 148                                         batadv_gw_node_free_ref(curr_gw);
 149                                 curr_gw = gw_node;
 150                                 atomic_inc(&curr_gw->refcount);
 151                         }
 152                         break;
 153
 154                 default: /* 2:  stable connection (use best statistic)
 155                           * 3:  fast-switch (use best statistic but change as
 156                           *     soon as a better gateway appears)
 157                           * XX: late-switch (use best statistic but change as
 158                           *     soon as a better gateway appears which has
 159                           *     $routing_class more tq points)
 160                           */
 161                         if (router->tq_avg > max_tq) {
 162                                 if (curr_gw)
 163                                         batadv_gw_node_free_ref(curr_gw);
 164                                 curr_gw = gw_node;
 165                                 atomic_inc(&curr_gw->refcount);
 166                         }
 167                         break;
 168                 }
 169
 170                 if (router->tq_avg > max_tq)
 171                         max_tq = router->tq_avg;
 172
 173                 if (tmp_gw_factor > max_gw_factor)
 174                         max_gw_factor = tmp_gw_factor;
 175
 176                 batadv_gw_node_free_ref(gw_node);
 177
 178 next:
 179                 batadv_neigh_node_free_ref(router);
 180         }
 181         rcu_read_unlock();
 182
 183         return curr_gw;
 184 }
 185
 186 void batadv_gw_election(struct bat_priv *bat_priv)
 187 {
 188         struct gw_node *curr_gw = NULL, *next_gw = NULL;
 189         struct neigh_node *router = NULL;
 190         char gw_addr[18] = { '\0' };
 191
 192         /* The batman daemon checks here if we already passed a full originator
 193          * cycle in order to make sure we don't choose the first gateway we
 194          * hear about. This check is based on the daemon's uptime which we
 195          * don't have.
 196          */
 197         if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 198                 goto out;
 199
 200         if (!batadv_atomic_dec_not_zero(&bat_priv->gw_reselect))
 201                 goto out;
 202
 203         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 204
 205         next_gw = batadv_gw_get_best_gw_node(bat_priv);
 206
 207         if (curr_gw == next_gw)
 208                 goto out;
 209
 210         if (next_gw) {
 211                 sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
 212
 213                 router = batadv_orig_node_get_router(next_gw->orig_node);
 214                 if (!router) {
 215                         batadv_gw_deselect(bat_priv);
 216                         goto out;
 217                 }
 218         }
 219
 220         if ((curr_gw) && (!next_gw)) {
 221                 batadv_dbg(DBG_BATMAN, bat_priv,
 222                            "Removing selected gateway - no gateway in range\n");
 223                 batadv_throw_uevent(bat_priv, UEV_GW, UEV_DEL, NULL);
 224         } else if ((!curr_gw) && (next_gw)) {
 225                 batadv_dbg(DBG_BATMAN, bat_priv,
 226                            "Adding route to gateway %pM (gw_flags: %i, tq: %i)\n",
 227                            next_gw->orig_node->orig,
 228                            next_gw->orig_node->gw_flags, router->tq_avg);
 229                 batadv_throw_uevent(bat_priv, UEV_GW, UEV_ADD, gw_addr);
 230         } else {
 231                 batadv_dbg(DBG_BATMAN, bat_priv,
 232                            "Changing route to gateway %pM (gw_flags: %i, tq: %i)\n",
 233                            next_gw->orig_node->orig,
 234                            next_gw->orig_node->gw_flags, router->tq_avg);
 235                 batadv_throw_uevent(bat_priv, UEV_GW, UEV_CHANGE, gw_addr);
 236         }
 237
 238         batadv_gw_select(bat_priv, next_gw);
 239
 240 out:
 241         if (curr_gw)
 242                 batadv_gw_node_free_ref(curr_gw);
 243         if (next_gw)
 244                 batadv_gw_node_free_ref(next_gw);
 245         if (router)
 246                 batadv_neigh_node_free_ref(router);
 247 }
 248
 249 void batadv_gw_check_election(struct bat_priv *bat_priv,
 250                               struct orig_node *orig_node)
 251 {
 252         struct orig_node *curr_gw_orig;
 253         struct neigh_node *router_gw = NULL, *router_orig = NULL;
 254         uint8_t gw_tq_avg, orig_tq_avg;
 255
 256         curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 257         if (!curr_gw_orig)
 258                 goto deselect;
 259
 260         router_gw = batadv_orig_node_get_router(curr_gw_orig);
 261         if (!router_gw)
 262                 goto deselect;
 263
 264         /* this node already is the gateway */
 265         if (curr_gw_orig == orig_node)
 266                 goto out;
 267
 268         router_orig = batadv_orig_node_get_router(orig_node);
 269         if (!router_orig)
 270                 goto out;
 271
 272         gw_tq_avg = router_gw->tq_avg;
 273         orig_tq_avg = router_orig->tq_avg;
 274
 275         /* the TQ value has to be better */
 276         if (orig_tq_avg < gw_tq_avg)
 277                 goto out;
 278
 279         /* if the routing class is greater than 3 the value tells us how much
 280          * greater the TQ value of the new gateway must be
 281          */
 282         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 283             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 284                 goto out;
 285
 286         batadv_dbg(DBG_BATMAN, bat_priv,
 287                    "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
 288                    gw_tq_avg, orig_tq_avg);
 289
 290 deselect:
 291         batadv_gw_deselect(bat_priv);
 292 out:
 293         if (curr_gw_orig)
 294                 batadv_orig_node_free_ref(curr_gw_orig);
 295         if (router_gw)
 296                 batadv_neigh_node_free_ref(router_gw);
 297         if (router_orig)
 298                 batadv_neigh_node_free_ref(router_orig);
 299
 300         return;
 301 }
 302
 303 static void batadv_gw_node_add(struct bat_priv *bat_priv,
 304                                struct orig_node *orig_node,
 305                                uint8_t new_gwflags)
 306 {
 307         struct gw_node *gw_node;
 308         int down, up;
 309
 310         gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 311         if (!gw_node)
 312                 return;
 313
 314         INIT_HLIST_NODE(&gw_node->list);
 315         gw_node->orig_node = orig_node;
 316         atomic_set(&gw_node->refcount, 1);
 317
 318         spin_lock_bh(&bat_priv->gw_list_lock);
 319         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
 320         spin_unlock_bh(&bat_priv->gw_list_lock);
 321
 322         batadv_gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 323         batadv_dbg(DBG_BATMAN, bat_priv,
 324                    "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
 325                    orig_node->orig, new_gwflags,
 326                    (down > 2048 ? down / 1024 : down),
 327                    (down > 2048 ? "MBit" : "KBit"),
 328                    (up > 2048 ? up / 1024 : up),
 329                    (up > 2048 ? "MBit" : "KBit"));
 330 }
 331
 332 void batadv_gw_node_update(struct bat_priv *bat_priv,
 333                            struct orig_node *orig_node, uint8_t new_gwflags)
 334 {
 335         struct hlist_node *node;
 336         struct gw_node *gw_node, *curr_gw;
 337
 338         /* Note: We don't need a NULL check here, since curr_gw never gets
 339          * dereferenced. If curr_gw is NULL we also should not exit as we may
 340          * have this gateway in our list (duplication check!) even though we
 341          * have no currently selected gateway.
 342          */
 343         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 344
 345         rcu_read_lock();
 346         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 347                 if (gw_node->orig_node != orig_node)
 348                         continue;
 349
 350                 batadv_dbg(DBG_BATMAN, bat_priv,
 351                            "Gateway class of originator %pM changed from %i to %i\n",
 352                            orig_node->orig, gw_node->orig_node->gw_flags,
 353                            new_gwflags);
 354
 355                 gw_node->deleted = 0;
 356
 357                 if (new_gwflags == BATADV_NO_FLAGS) {
 358                         gw_node->deleted = jiffies;
 359                         batadv_dbg(DBG_BATMAN, bat_priv,
 360                                    "Gateway %pM removed from gateway list\n",
 361                                    orig_node->orig);
 362
 363                         if (gw_node == curr_gw)
 364                                 goto deselect;
 365                 }
 366
 367                 goto unlock;
 368         }
 369
 370         if (new_gwflags == BATADV_NO_FLAGS)
 371                 goto unlock;
 372
 373         batadv_gw_node_add(bat_priv, orig_node, new_gwflags);
 374         goto unlock;
 375
 376 deselect:
 377         batadv_gw_deselect(bat_priv);
 378 unlock:
 379         rcu_read_unlock();
 380
 381         if (curr_gw)
 382                 batadv_gw_node_free_ref(curr_gw);
 383 }
 384
 385 void batadv_gw_node_delete(struct bat_priv *bat_priv,
 386                            struct orig_node *orig_node)
 387 {
 388         batadv_gw_node_update(bat_priv, orig_node, 0);
 389 }
 390
 391 void batadv_gw_node_purge(struct bat_priv *bat_priv)
 392 {
 393         struct gw_node *gw_node, *curr_gw;
 394         struct hlist_node *node, *node_tmp;
 395         unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT);
 396         int do_deselect = 0;
 397
 398         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 399
 400         spin_lock_bh(&bat_priv->gw_list_lock);
 401
 402         hlist_for_each_entry_safe(gw_node, node, node_tmp,
 403                                   &bat_priv->gw_list, list) {
 404                 if (((!gw_node->deleted) ||
 405                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 406                     atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 407                         continue;
 408
 409                 if (curr_gw == gw_node)
 410                         do_deselect = 1;
 411
 412                 hlist_del_rcu(&gw_node->list);
 413                 batadv_gw_node_free_ref(gw_node);
 414         }
 415
 416         spin_unlock_bh(&bat_priv->gw_list_lock);
 417
 418         /* gw_deselect() needs to acquire the gw_list_lock */
 419         if (do_deselect)
 420                 batadv_gw_deselect(bat_priv);
 421
 422         if (curr_gw)
 423                 batadv_gw_node_free_ref(curr_gw);
 424 }
 425
 426 /* fails if orig_node has no router */
 427 static int batadv_write_buffer_text(struct bat_priv *bat_priv,
 428                                      struct seq_file *seq,
 429                                      const struct gw_node *gw_node)
 430 {
 431         struct gw_node *curr_gw;
 432         struct neigh_node *router;
 433         int down, up, ret = -1;
 434
 435         batadv_gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 436
 437         router = batadv_orig_node_get_router(gw_node->orig_node);
 438         if (!router)
 439                 goto out;
 440
 441         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 442
 443         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 444                          (curr_gw == gw_node ? "=>" : "  "),
 445                          gw_node->orig_node->orig,
 446                          router->tq_avg, router->addr,
 447                          router->if_incoming->net_dev->name,
 448                          gw_node->orig_node->gw_flags,
 449                          (down > 2048 ? down / 1024 : down),
 450                          (down > 2048 ? "MBit" : "KBit"),
 451                          (up > 2048 ? up / 1024 : up),
 452                          (up > 2048 ? "MBit" : "KBit"));
 453
 454         batadv_neigh_node_free_ref(router);
 455         if (curr_gw)
 456                 batadv_gw_node_free_ref(curr_gw);
 457 out:
 458         return ret;
 459 }
 460
 461 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 462 {
 463         struct net_device *net_dev = (struct net_device *)seq->private;
 464         struct bat_priv *bat_priv = netdev_priv(net_dev);
 465         struct hard_iface *primary_if;
 466         struct gw_node *gw_node;
 467         struct hlist_node *node;
 468         int gw_count = 0, ret = 0;
 469
 470         primary_if = batadv_primary_if_get_selected(bat_priv);
 471         if (!primary_if) {
 472                 ret = seq_printf(seq,
 473                                  "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
 474                                  net_dev->name);
 475                 goto out;
 476         }
 477
 478         if (primary_if->if_status != IF_ACTIVE) {
 479                 ret = seq_printf(seq,
 480                                  "BATMAN mesh %s disabled - primary interface not active\n",
 481                                  net_dev->name);
 482                 goto out;
 483         }
 484
 485         seq_printf(seq,
 486                    "      %-12s (%s/%i) %17s [%10s]: gw_class ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 487                    "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
 488                    BATADV_SOURCE_VERSION, primary_if->net_dev->name,
 489                    primary_if->net_dev->dev_addr, net_dev->name);
 490
 491         rcu_read_lock();
 492         hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 493                 if (gw_node->deleted)
 494                         continue;
 495
 496                 /* fails if orig_node has no router */
 497                 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
 498                         continue;
 499
 500                 gw_count++;
 501         }
 502         rcu_read_unlock();
 503
 504         if (gw_count == 0)
 505                 seq_printf(seq, "No gateways in range ...\n");
 506
 507 out:
 508         if (primary_if)
 509                 batadv_hardif_free_ref(primary_if);
 510         return ret;
 511 }
 512
 513 static bool batadv_is_type_dhcprequest(struct sk_buff *skb, int header_len)
 514 {
 515         int ret = false;
 516         unsigned char *p;
 517         int pkt_len;
 518
 519         if (skb_linearize(skb) < 0)
 520                 goto out;
 521
 522         pkt_len = skb_headlen(skb);
 523
 524         if (pkt_len < header_len + BATADV_DHCP_OPTIONS_OFFSET + 1)
 525                 goto out;
 526
 527         p = skb->data + header_len + BATADV_DHCP_OPTIONS_OFFSET;
 528         pkt_len -= header_len + BATADV_DHCP_OPTIONS_OFFSET + 1;
 529
 530         /* Access the dhcp option lists. Each entry is made up by:
 531          * - octet 1: option type
 532          * - octet 2: option data len (only if type != 255 and 0)
 533          * - octet 3: option data
 534          */
 535         while (*p != 255 && !ret) {
 536                 /* p now points to the first octet: option type */
 537                 if (*p == 53) {
 538                         /* type 53 is the message type option.
 539                          * Jump the len octet and go to the data octet
 540                          */
 541                         if (pkt_len < 2)
 542                                 goto out;
 543                         p += 2;
 544
 545                         /* check if the message type is what we need */
 546                         if (*p == BATADV_DHCP_REQUEST)
 547                                 ret = true;
 548                         break;
 549                 } else if (*p == 0) {
 550                         /* option type 0 (padding), just go forward */
 551                         if (pkt_len < 1)
 552                                 goto out;
 553                         pkt_len--;
 554                         p++;
 555                 } else {
 556                         /* This is any other option. So we get the length... */
 557                         if (pkt_len < 1)
 558                                 goto out;
 559                         pkt_len--;
 560                         p++;
 561
 562                         /* ...and then we jump over the data */
 563                         if (pkt_len < 1 + (*p))
 564                                 goto out;
 565                         pkt_len -= 1 + (*p);
 566                         p += 1 + (*p);
 567                 }
 568         }
 569 out:
 570         return ret;
 571 }
 572
 573 bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len)
 574 {
 575         struct ethhdr *ethhdr;
 576         struct iphdr *iphdr;
 577         struct ipv6hdr *ipv6hdr;
 578         struct udphdr *udphdr;
 579
 580         /* check for ethernet header */
 581         if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
 582                 return false;
 583         ethhdr = (struct ethhdr *)skb->data;
 584         *header_len += ETH_HLEN;
 585
 586         /* check for initial vlan header */
 587         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 588                 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
 589                         return false;
 590                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 591                 *header_len += VLAN_HLEN;
 592         }
 593
 594         /* check for ip header */
 595         switch (ntohs(ethhdr->h_proto)) {
 596         case ETH_P_IP:
 597                 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
 598                         return false;
 599                 iphdr = (struct iphdr *)(skb->data + *header_len);
 600                 *header_len += iphdr->ihl * 4;
 601
 602                 /* check for udp header */
 603                 if (iphdr->protocol != IPPROTO_UDP)
 604                         return false;
 605
 606                 break;
 607         case ETH_P_IPV6:
 608                 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
 609                         return false;
 610                 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
 611                 *header_len += sizeof(*ipv6hdr);
 612
 613                 /* check for udp header */
 614                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 615                         return false;
 616
 617                 break;
 618         default:
 619                 return false;
 620         }
 621
 622         if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
 623                 return false;
 624         udphdr = (struct udphdr *)(skb->data + *header_len);
 625         *header_len += sizeof(*udphdr);
 626
 627         /* check for bootp port */
 628         if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
 629             (ntohs(udphdr->dest) != 67))
 630                 return false;
 631
 632         if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
 633             (ntohs(udphdr->dest) != 547))
 634                 return false;
 635
 636         return true;
 637 }
 638
 639 bool batadv_gw_out_of_range(struct bat_priv *bat_priv,
 640                             struct sk_buff *skb, struct ethhdr *ethhdr)
 641 {
 642         struct neigh_node *neigh_curr = NULL, *neigh_old = NULL;
 643         struct orig_node *orig_dst_node = NULL;
 644         struct gw_node *curr_gw = NULL;
 645         bool ret, out_of_range = false;
 646         unsigned int header_len = 0;
 647         uint8_t curr_tq_avg;
 648
 649         ret = batadv_gw_is_dhcp_target(skb, &header_len);
 650         if (!ret)
 651                 goto out;
 652
 653         orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
 654                                                  ethhdr->h_dest);
 655         if (!orig_dst_node)
 656                 goto out;
 657
 658         if (!orig_dst_node->gw_flags)
 659                 goto out;
 660
 661         ret = batadv_is_type_dhcprequest(skb, header_len);
 662         if (!ret)
 663                 goto out;
 664
 665         switch (atomic_read(&bat_priv->gw_mode)) {
 666         case GW_MODE_SERVER:
 667                 /* If we are a GW then we are our best GW. We can artificially
 668                  * set the tq towards ourself as the maximum value
 669                  */
 670                 curr_tq_avg = BATADV_TQ_MAX_VALUE;
 671                 break;
 672         case GW_MODE_CLIENT:
 673                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 674                 if (!curr_gw)
 675                         goto out;
 676
 677                 /* packet is going to our gateway */
 678                 if (curr_gw->orig_node == orig_dst_node)
 679                         goto out;
 680
 681                 /* If the dhcp packet has been sent to a different gw,
 682                  * we have to evaluate whether the old gw is still
 683                  * reliable enough
 684                  */
 685                 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
 686                                                 NULL);
 687                 if (!neigh_curr)
 688                         goto out;
 689
 690                 curr_tq_avg = neigh_curr->tq_avg;
 691                 break;
 692         case GW_MODE_OFF:
 693         default:
 694                 goto out;
 695         }
 696
 697         neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
 698         if (!neigh_old)
 699                 goto out;
 700
 701         if (curr_tq_avg - neigh_old->tq_avg > BATADV_GW_THRESHOLD)
 702                 out_of_range = true;
 703
 704 out:
 705         if (orig_dst_node)
 706                 batadv_orig_node_free_ref(orig_dst_node);
 707         if (curr_gw)
 708                 batadv_gw_node_free_ref(curr_gw);
 709         if (neigh_old)
 710                 batadv_neigh_node_free_ref(neigh_old);
 711         if (neigh_curr)
 712                 batadv_neigh_node_free_ref(neigh_curr);
 713         return out_of_range;
 714 }