net/batman-adv/gateway_client.c

   1 /* Copyright (C) 2009-2013 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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "main.h"
  19 #include "sysfs.h"
  20 #include "gateway_client.h"
  21 #include "gateway_common.h"
  22 #include "hard-interface.h"
  23 #include "originator.h"
  24 #include "translation-table.h"
  25 #include "routing.h"
  26 #include <linux/ip.h>
  27 #include <linux/ipv6.h>
  28 #include <linux/udp.h>
  29 #include <linux/if_vlan.h>
  30
  31 /* These are the offsets of the "hw type" and "hw address length" in the dhcp
  32  * packet starting at the beginning of the dhcp header
  33  */
  34 #define BATADV_DHCP_HTYPE_OFFSET        1
  35 #define BATADV_DHCP_HLEN_OFFSET         2
  36 /* Value of htype representing Ethernet */
  37 #define BATADV_DHCP_HTYPE_ETHERNET      0x01
  38 /* This is the offset of the "chaddr" field in the dhcp packet starting at the
  39  * beginning of the dhcp header
  40  */
  41 #define BATADV_DHCP_CHADDR_OFFSET       28
  42
  43 static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
  44 {
  45         if (atomic_dec_and_test(&gw_node->refcount))
  46                 kfree_rcu(gw_node, rcu);
  47 }
  48
  49 static struct batadv_gw_node *
  50 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
  51 {
  52         struct batadv_gw_node *gw_node;
  53
  54         rcu_read_lock();
  55         gw_node = rcu_dereference(bat_priv->gw.curr_gw);
  56         if (!gw_node)
  57                 goto out;
  58
  59         if (!atomic_inc_not_zero(&gw_node->refcount))
  60                 gw_node = NULL;
  61
  62 out:
  63         rcu_read_unlock();
  64         return gw_node;
  65 }
  66
  67 struct batadv_orig_node *
  68 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
  69 {
  70         struct batadv_gw_node *gw_node;
  71         struct batadv_orig_node *orig_node = NULL;
  72
  73         gw_node = batadv_gw_get_selected_gw_node(bat_priv);
  74         if (!gw_node)
  75                 goto out;
  76
  77         rcu_read_lock();
  78         orig_node = gw_node->orig_node;
  79         if (!orig_node)
  80                 goto unlock;
  81
  82         if (!atomic_inc_not_zero(&orig_node->refcount))
  83                 orig_node = NULL;
  84
  85 unlock:
  86         rcu_read_unlock();
  87 out:
  88         if (gw_node)
  89                 batadv_gw_node_free_ref(gw_node);
  90         return orig_node;
  91 }
  92
  93 static void batadv_gw_select(struct batadv_priv *bat_priv,
  94                              struct batadv_gw_node *new_gw_node)
  95 {
  96         struct batadv_gw_node *curr_gw_node;
  97
  98         spin_lock_bh(&bat_priv->gw.list_lock);
  99
 100         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
 101                 new_gw_node = NULL;
 102
 103         curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1);
 104         rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node);
 105
 106         if (curr_gw_node)
 107                 batadv_gw_node_free_ref(curr_gw_node);
 108
 109         spin_unlock_bh(&bat_priv->gw.list_lock);
 110 }
 111
 112 /**
 113  * batadv_gw_reselect - force a gateway reselection
 114  * @bat_priv: the bat priv with all the soft interface information
 115  *
 116  * Set a flag to remind the GW component to perform a new gateway reselection.
 117  * However this function does not ensure that the current gateway is going to be
 118  * deselected. The reselection mechanism may elect the same gateway once again.
 119  *
 120  * This means that invoking batadv_gw_reselect() does not guarantee a gateway
 121  * change and therefore a uevent is not necessarily expected.
 122  */
 123 void batadv_gw_reselect(struct batadv_priv *bat_priv)
 124 {
 125         atomic_set(&bat_priv->gw.reselect, 1);
 126 }
 127
 128 static struct batadv_gw_node *
 129 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
 130 {
 131         struct batadv_neigh_node *router;
 132         struct batadv_neigh_ifinfo *router_ifinfo;
 133         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 134         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 135         uint32_t gw_divisor;
 136         uint8_t max_tq = 0;
 137         uint8_t tq_avg;
 138         struct batadv_orig_node *orig_node;
 139
 140         gw_divisor = BATADV_TQ_LOCAL_WINDOW_SIZE * BATADV_TQ_LOCAL_WINDOW_SIZE;
 141         gw_divisor *= 64;
 142
 143         rcu_read_lock();
 144         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 145                 if (gw_node->deleted)
 146                         continue;
 147
 148                 orig_node = gw_node->orig_node;
 149                 router = batadv_orig_node_get_router(orig_node);
 150                 if (!router)
 151                         continue;
 152
 153                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 154                                                         BATADV_IF_DEFAULT);
 155                 if (!router_ifinfo)
 156                         goto next;
 157
 158                 if (!atomic_inc_not_zero(&gw_node->refcount))
 159                         goto next;
 160
 161                 tq_avg = router_ifinfo->bat_iv.tq_avg;
 162
 163                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 164                 case 1: /* fast connection */
 165                         tmp_gw_factor = tq_avg * tq_avg;
 166                         tmp_gw_factor *= gw_node->bandwidth_down;
 167                         tmp_gw_factor *= 100 * 100;
 168                         tmp_gw_factor /= gw_divisor;
 169
 170                         if ((tmp_gw_factor > max_gw_factor) ||
 171                             ((tmp_gw_factor == max_gw_factor) &&
 172                              (tq_avg > max_tq))) {
 173                                 if (curr_gw)
 174                                         batadv_gw_node_free_ref(curr_gw);
 175                                 curr_gw = gw_node;
 176                                 atomic_inc(&curr_gw->refcount);
 177                         }
 178                         break;
 179
 180                 default: /* 2:  stable connection (use best statistic)
 181                           * 3:  fast-switch (use best statistic but change as
 182                           *     soon as a better gateway appears)
 183                           * XX: late-switch (use best statistic but change as
 184                           *     soon as a better gateway appears which has
 185                           *     $routing_class more tq points)
 186                           */
 187                         if (tq_avg > max_tq) {
 188                                 if (curr_gw)
 189                                         batadv_gw_node_free_ref(curr_gw);
 190                                 curr_gw = gw_node;
 191                                 atomic_inc(&curr_gw->refcount);
 192                         }
 193                         break;
 194                 }
 195
 196                 if (tq_avg > max_tq)
 197                         max_tq = tq_avg;
 198
 199                 if (tmp_gw_factor > max_gw_factor)
 200                         max_gw_factor = tmp_gw_factor;
 201
 202                 batadv_gw_node_free_ref(gw_node);
 203
 204 next:
 205                 batadv_neigh_node_free_ref(router);
 206                 if (router_ifinfo)
 207                         batadv_neigh_ifinfo_free_ref(router_ifinfo);
 208         }
 209         rcu_read_unlock();
 210
 211         return curr_gw;
 212 }
 213
 214 /**
 215  * batadv_gw_check_client_stop - check if client mode has been switched off
 216  * @bat_priv: the bat priv with all the soft interface information
 217  *
 218  * This function assumes the caller has checked that the gw state *is actually
 219  * changing*. This function is not supposed to be called when there is no state
 220  * change.
 221  */
 222 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
 223 {
 224         struct batadv_gw_node *curr_gw;
 225
 226         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 227                 return;
 228
 229         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 230         if (!curr_gw)
 231                 return;
 232
 233         /* deselect the current gateway so that next time that client mode is
 234          * enabled a proper GW_ADD event can be sent
 235          */
 236         batadv_gw_select(bat_priv, NULL);
 237
 238         /* if batman-adv is switching the gw client mode off and a gateway was
 239          * already selected, send a DEL uevent
 240          */
 241         batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
 242
 243         batadv_gw_node_free_ref(curr_gw);
 244 }
 245
 246 void batadv_gw_election(struct batadv_priv *bat_priv)
 247 {
 248         struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL;
 249         struct batadv_neigh_node *router = NULL;
 250         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 251         char gw_addr[18] = { '\0' };
 252
 253         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 254                 goto out;
 255
 256         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 257
 258         if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
 259                 goto out;
 260
 261         next_gw = batadv_gw_get_best_gw_node(bat_priv);
 262
 263         if (curr_gw == next_gw)
 264                 goto out;
 265
 266         if (next_gw) {
 267                 sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
 268
 269                 router = batadv_orig_node_get_router(next_gw->orig_node);
 270                 if (!router) {
 271                         batadv_gw_reselect(bat_priv);
 272                         goto out;
 273                 }
 274
 275                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 276                                                         BATADV_IF_DEFAULT);
 277                 if (!router_ifinfo) {
 278                         batadv_gw_reselect(bat_priv);
 279                         goto out;
 280                 }
 281         }
 282
 283         if ((curr_gw) && (!next_gw)) {
 284                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 285                            "Removing selected gateway - no gateway in range\n");
 286                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
 287                                     NULL);
 288         } else if ((!curr_gw) && (next_gw)) {
 289                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 290                            "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 291                            next_gw->orig_node->orig,
 292                            next_gw->bandwidth_down / 10,
 293                            next_gw->bandwidth_down % 10,
 294                            next_gw->bandwidth_up / 10,
 295                            next_gw->bandwidth_up % 10,
 296                            router_ifinfo->bat_iv.tq_avg);
 297                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
 298                                     gw_addr);
 299         } else {
 300                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 301                            "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 302                            next_gw->orig_node->orig,
 303                            next_gw->bandwidth_down / 10,
 304                            next_gw->bandwidth_down % 10,
 305                            next_gw->bandwidth_up / 10,
 306                            next_gw->bandwidth_up % 10,
 307                            router_ifinfo->bat_iv.tq_avg);
 308                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
 309                                     gw_addr);
 310         }
 311
 312         batadv_gw_select(bat_priv, next_gw);
 313
 314 out:
 315         if (curr_gw)
 316                 batadv_gw_node_free_ref(curr_gw);
 317         if (next_gw)
 318                 batadv_gw_node_free_ref(next_gw);
 319         if (router)
 320                 batadv_neigh_node_free_ref(router);
 321         if (router_ifinfo)
 322                 batadv_neigh_ifinfo_free_ref(router_ifinfo);
 323 }
 324
 325 void batadv_gw_check_election(struct batadv_priv *bat_priv,
 326                               struct batadv_orig_node *orig_node)
 327 {
 328         struct batadv_neigh_ifinfo *router_orig_tq = NULL;
 329         struct batadv_neigh_ifinfo *router_gw_tq = NULL;
 330         struct batadv_orig_node *curr_gw_orig;
 331         struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL;
 332         uint8_t gw_tq_avg, orig_tq_avg;
 333
 334         curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 335         if (!curr_gw_orig)
 336                 goto reselect;
 337
 338         router_gw = batadv_orig_node_get_router(curr_gw_orig);
 339         if (!router_gw)
 340                 goto reselect;
 341
 342         router_gw_tq = batadv_neigh_ifinfo_get(router_gw,
 343                                                BATADV_IF_DEFAULT);
 344         if (!router_gw_tq)
 345                 goto reselect;
 346
 347         /* this node already is the gateway */
 348         if (curr_gw_orig == orig_node)
 349                 goto out;
 350
 351         router_orig = batadv_orig_node_get_router(orig_node);
 352         if (!router_orig)
 353                 goto out;
 354
 355         router_orig_tq = batadv_neigh_ifinfo_get(router_orig,
 356                                                  BATADV_IF_DEFAULT);
 357         if (!router_orig_tq)
 358                 goto out;
 359
 360         gw_tq_avg = router_gw_tq->bat_iv.tq_avg;
 361         orig_tq_avg = router_orig_tq->bat_iv.tq_avg;
 362
 363         /* the TQ value has to be better */
 364         if (orig_tq_avg < gw_tq_avg)
 365                 goto out;
 366
 367         /* if the routing class is greater than 3 the value tells us how much
 368          * greater the TQ value of the new gateway must be
 369          */
 370         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 371             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 372                 goto out;
 373
 374         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 375                    "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
 376                    gw_tq_avg, orig_tq_avg);
 377
 378 reselect:
 379         batadv_gw_reselect(bat_priv);
 380 out:
 381         if (curr_gw_orig)
 382                 batadv_orig_node_free_ref(curr_gw_orig);
 383         if (router_gw)
 384                 batadv_neigh_node_free_ref(router_gw);
 385         if (router_orig)
 386                 batadv_neigh_node_free_ref(router_orig);
 387         if (router_gw_tq)
 388                 batadv_neigh_ifinfo_free_ref(router_gw_tq);
 389         if (router_orig_tq)
 390                 batadv_neigh_ifinfo_free_ref(router_orig_tq);
 391
 392         return;
 393 }
 394
 395 /**
 396  * batadv_gw_node_add - add gateway node to list of available gateways
 397  * @bat_priv: the bat priv with all the soft interface information
 398  * @orig_node: originator announcing gateway capabilities
 399  * @gateway: announced bandwidth information
 400  */
 401 static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 402                                struct batadv_orig_node *orig_node,
 403                                struct batadv_tvlv_gateway_data *gateway)
 404 {
 405         struct batadv_gw_node *gw_node;
 406
 407         if (gateway->bandwidth_down == 0)
 408                 return;
 409
 410         gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 411         if (!gw_node)
 412                 return;
 413
 414         INIT_HLIST_NODE(&gw_node->list);
 415         gw_node->orig_node = orig_node;
 416         atomic_set(&gw_node->refcount, 1);
 417
 418         spin_lock_bh(&bat_priv->gw.list_lock);
 419         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list);
 420         spin_unlock_bh(&bat_priv->gw.list_lock);
 421
 422         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 423                    "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
 424                    orig_node->orig,
 425                    ntohl(gateway->bandwidth_down) / 10,
 426                    ntohl(gateway->bandwidth_down) % 10,
 427                    ntohl(gateway->bandwidth_up) / 10,
 428                    ntohl(gateway->bandwidth_up) % 10);
 429 }
 430
 431 /**
 432  * batadv_gw_node_get - retrieve gateway node from list of available gateways
 433  * @bat_priv: the bat priv with all the soft interface information
 434  * @orig_node: originator announcing gateway capabilities
 435  *
 436  * Returns gateway node if found or NULL otherwise.
 437  */
 438 static struct batadv_gw_node *
 439 batadv_gw_node_get(struct batadv_priv *bat_priv,
 440                    struct batadv_orig_node *orig_node)
 441 {
 442         struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
 443
 444         rcu_read_lock();
 445         hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) {
 446                 if (gw_node_tmp->orig_node != orig_node)
 447                         continue;
 448
 449                 if (gw_node_tmp->deleted)
 450                         continue;
 451
 452                 if (!atomic_inc_not_zero(&gw_node_tmp->refcount))
 453                         continue;
 454
 455                 gw_node = gw_node_tmp;
 456                 break;
 457         }
 458         rcu_read_unlock();
 459
 460         return gw_node;
 461 }
 462
 463 /**
 464  * batadv_gw_node_update - update list of available gateways with changed
 465  *  bandwidth information
 466  * @bat_priv: the bat priv with all the soft interface information
 467  * @orig_node: originator announcing gateway capabilities
 468  * @gateway: announced bandwidth information
 469  */
 470 void batadv_gw_node_update(struct batadv_priv *bat_priv,
 471                            struct batadv_orig_node *orig_node,
 472                            struct batadv_tvlv_gateway_data *gateway)
 473 {
 474         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 475
 476         gw_node = batadv_gw_node_get(bat_priv, orig_node);
 477         if (!gw_node) {
 478                 batadv_gw_node_add(bat_priv, orig_node, gateway);
 479                 goto out;
 480         }
 481
 482         if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) &&
 483             (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up)))
 484                 goto out;
 485
 486         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 487                    "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
 488                    orig_node->orig,
 489                    gw_node->bandwidth_down / 10,
 490                    gw_node->bandwidth_down % 10,
 491                    gw_node->bandwidth_up / 10,
 492                    gw_node->bandwidth_up % 10,
 493                    ntohl(gateway->bandwidth_down) / 10,
 494                    ntohl(gateway->bandwidth_down) % 10,
 495                    ntohl(gateway->bandwidth_up) / 10,
 496                    ntohl(gateway->bandwidth_up) % 10);
 497
 498         gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 499         gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 500
 501         gw_node->deleted = 0;
 502         if (ntohl(gateway->bandwidth_down) == 0) {
 503                 gw_node->deleted = jiffies;
 504                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 505                            "Gateway %pM removed from gateway list\n",
 506                            orig_node->orig);
 507
 508                 /* Note: We don't need a NULL check here, since curr_gw never
 509                  * gets dereferenced.
 510                  */
 511                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 512                 if (gw_node == curr_gw)
 513                         batadv_gw_reselect(bat_priv);
 514         }
 515
 516 out:
 517         if (curr_gw)
 518                 batadv_gw_node_free_ref(curr_gw);
 519         if (gw_node)
 520                 batadv_gw_node_free_ref(gw_node);
 521 }
 522
 523 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 524                            struct batadv_orig_node *orig_node)
 525 {
 526         struct batadv_tvlv_gateway_data gateway;
 527
 528         gateway.bandwidth_down = 0;
 529         gateway.bandwidth_up = 0;
 530
 531         batadv_gw_node_update(bat_priv, orig_node, &gateway);
 532 }
 533
 534 void batadv_gw_node_purge(struct batadv_priv *bat_priv)
 535 {
 536         struct batadv_gw_node *gw_node, *curr_gw;
 537         struct hlist_node *node_tmp;
 538         unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT);
 539         int do_reselect = 0;
 540
 541         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 542
 543         spin_lock_bh(&bat_priv->gw.list_lock);
 544
 545         hlist_for_each_entry_safe(gw_node, node_tmp,
 546                                   &bat_priv->gw.list, list) {
 547                 if (((!gw_node->deleted) ||
 548                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 549                     atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE)
 550                         continue;
 551
 552                 if (curr_gw == gw_node)
 553                         do_reselect = 1;
 554
 555                 hlist_del_rcu(&gw_node->list);
 556                 batadv_gw_node_free_ref(gw_node);
 557         }
 558
 559         spin_unlock_bh(&bat_priv->gw.list_lock);
 560
 561         /* gw_reselect() needs to acquire the gw_list_lock */
 562         if (do_reselect)
 563                 batadv_gw_reselect(bat_priv);
 564
 565         if (curr_gw)
 566                 batadv_gw_node_free_ref(curr_gw);
 567 }
 568
 569 /* fails if orig_node has no router */
 570 static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
 571                                     struct seq_file *seq,
 572                                     const struct batadv_gw_node *gw_node)
 573 {
 574         struct batadv_gw_node *curr_gw;
 575         struct batadv_neigh_node *router;
 576         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 577         int ret = -1;
 578
 579         router = batadv_orig_node_get_router(gw_node->orig_node);
 580         if (!router)
 581                 goto out;
 582
 583         router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
 584         if (!router_ifinfo)
 585                 goto out;
 586
 587         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 588
 589         ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
 590                          (curr_gw == gw_node ? "=>" : "  "),
 591                          gw_node->orig_node->orig,
 592                          router_ifinfo->bat_iv.tq_avg, router->addr,
 593                          router->if_incoming->net_dev->name,
 594                          gw_node->bandwidth_down / 10,
 595                          gw_node->bandwidth_down % 10,
 596                          gw_node->bandwidth_up / 10,
 597                          gw_node->bandwidth_up % 10);
 598
 599         if (curr_gw)
 600                 batadv_gw_node_free_ref(curr_gw);
 601 out:
 602         if (router_ifinfo)
 603                 batadv_neigh_ifinfo_free_ref(router_ifinfo);
 604         if (router)
 605                 batadv_neigh_node_free_ref(router);
 606         return ret;
 607 }
 608
 609 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 610 {
 611         struct net_device *net_dev = (struct net_device *)seq->private;
 612         struct batadv_priv *bat_priv = netdev_priv(net_dev);
 613         struct batadv_hard_iface *primary_if;
 614         struct batadv_gw_node *gw_node;
 615         int gw_count = 0;
 616
 617         primary_if = batadv_seq_print_text_primary_if_get(seq);
 618         if (!primary_if)
 619                 goto out;
 620
 621         seq_printf(seq,
 622                    "      %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 623                    "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
 624                    BATADV_SOURCE_VERSION, primary_if->net_dev->name,
 625                    primary_if->net_dev->dev_addr, net_dev->name);
 626
 627         rcu_read_lock();
 628         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 629                 if (gw_node->deleted)
 630                         continue;
 631
 632                 /* fails if orig_node has no router */
 633                 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
 634                         continue;
 635
 636                 gw_count++;
 637         }
 638         rcu_read_unlock();
 639
 640         if (gw_count == 0)
 641                 seq_puts(seq, "No gateways in range ...\n");
 642
 643 out:
 644         if (primary_if)
 645                 batadv_hardif_free_ref(primary_if);
 646         return 0;
 647 }
 648
 649 /**
 650  * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message
 651  * @skb: the packet to check
 652  * @header_len: a pointer to the batman-adv header size
 653  * @chaddr: buffer where the client address will be stored. Valid
 654  *  only if the function returns BATADV_DHCP_TO_CLIENT
 655  *
 656  * Returns:
 657  * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
 658  *   while parsing it
 659  * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
 660  * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
 661  *
 662  * This function may re-allocate the data buffer of the skb passed as argument.
 663  */
 664 enum batadv_dhcp_recipient
 665 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
 666                              uint8_t *chaddr)
 667 {
 668         enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
 669         struct ethhdr *ethhdr;
 670         struct iphdr *iphdr;
 671         struct ipv6hdr *ipv6hdr;
 672         struct udphdr *udphdr;
 673         struct vlan_ethhdr *vhdr;
 674         int chaddr_offset;
 675         __be16 proto;
 676         uint8_t *p;
 677
 678         /* check for ethernet header */
 679         if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
 680                 return BATADV_DHCP_NO;
 681
 682         ethhdr = (struct ethhdr *)skb->data;
 683         proto = ethhdr->h_proto;
 684         *header_len += ETH_HLEN;
 685
 686         /* check for initial vlan header */
 687         if (proto == htons(ETH_P_8021Q)) {
 688                 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
 689                         return BATADV_DHCP_NO;
 690
 691                 vhdr = (struct vlan_ethhdr *)skb->data;
 692                 proto = vhdr->h_vlan_encapsulated_proto;
 693                 *header_len += VLAN_HLEN;
 694         }
 695
 696         /* check for ip header */
 697         switch (proto) {
 698         case htons(ETH_P_IP):
 699                 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
 700                         return BATADV_DHCP_NO;
 701
 702                 iphdr = (struct iphdr *)(skb->data + *header_len);
 703                 *header_len += iphdr->ihl * 4;
 704
 705                 /* check for udp header */
 706                 if (iphdr->protocol != IPPROTO_UDP)
 707                         return BATADV_DHCP_NO;
 708
 709                 break;
 710         case htons(ETH_P_IPV6):
 711                 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
 712                         return BATADV_DHCP_NO;
 713
 714                 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
 715                 *header_len += sizeof(*ipv6hdr);
 716
 717                 /* check for udp header */
 718                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 719                         return BATADV_DHCP_NO;
 720
 721                 break;
 722         default:
 723                 return BATADV_DHCP_NO;
 724         }
 725
 726         if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
 727                 return BATADV_DHCP_NO;
 728
 729         /* skb->data might have been reallocated by pskb_may_pull() */
 730         ethhdr = (struct ethhdr *)skb->data;
 731         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q)
 732                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 733
 734         udphdr = (struct udphdr *)(skb->data + *header_len);
 735         *header_len += sizeof(*udphdr);
 736
 737         /* check for bootp port */
 738         switch (proto) {
 739         case htons(ETH_P_IP):
 740                 if (udphdr->dest == htons(67))
 741                         ret = BATADV_DHCP_TO_SERVER;
 742                 else if (udphdr->source == htons(67))
 743                         ret = BATADV_DHCP_TO_CLIENT;
 744                 break;
 745         case htons(ETH_P_IPV6):
 746                 if (udphdr->dest == htons(547))
 747                         ret = BATADV_DHCP_TO_SERVER;
 748                 else if (udphdr->source == htons(547))
 749                         ret = BATADV_DHCP_TO_CLIENT;
 750                 break;
 751         }
 752
 753         chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
 754         /* store the client address if the message is going to a client */
 755         if (ret == BATADV_DHCP_TO_CLIENT &&
 756             pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) {
 757                 /* check if the DHCP packet carries an Ethernet DHCP */
 758                 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
 759                 if (*p != BATADV_DHCP_HTYPE_ETHERNET)
 760                         return BATADV_DHCP_NO;
 761
 762                 /* check if the DHCP packet carries a valid Ethernet address */
 763                 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
 764                 if (*p != ETH_ALEN)
 765                         return BATADV_DHCP_NO;
 766
 767                 memcpy(chaddr, skb->data + chaddr_offset, ETH_ALEN);
 768         }
 769
 770         return ret;
 771 }
 772 /**
 773  * batadv_gw_out_of_range - check if the dhcp request destination is the best gw
 774  * @bat_priv: the bat priv with all the soft interface information
 775  * @skb: the outgoing packet
 776  *
 777  * Check if the skb is a DHCP request and if it is sent to the current best GW
 778  * server. Due to topology changes it may be the case that the GW server
 779  * previously selected is not the best one anymore.
 780  *
 781  * Returns true if the packet destination is unicast and it is not the best gw,
 782  * false otherwise.
 783  *
 784  * This call might reallocate skb data.
 785  * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
 786  */
 787 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 788                             struct sk_buff *skb)
 789 {
 790         struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL;
 791         struct batadv_orig_node *orig_dst_node = NULL;
 792         struct batadv_gw_node *gw_node = NULL, *curr_gw = NULL;
 793         struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
 794         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 795         bool out_of_range = false;
 796         uint8_t curr_tq_avg;
 797         unsigned short vid;
 798
 799         vid = batadv_get_vid(skb, 0);
 800
 801         orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
 802                                                  ethhdr->h_dest, vid);
 803         if (!orig_dst_node)
 804                 goto out;
 805
 806         gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
 807         if (!gw_node->bandwidth_down == 0)
 808                 goto out;
 809
 810         switch (atomic_read(&bat_priv->gw_mode)) {
 811         case BATADV_GW_MODE_SERVER:
 812                 /* If we are a GW then we are our best GW. We can artificially
 813                  * set the tq towards ourself as the maximum value
 814                  */
 815                 curr_tq_avg = BATADV_TQ_MAX_VALUE;
 816                 break;
 817         case BATADV_GW_MODE_CLIENT:
 818                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 819                 if (!curr_gw)
 820                         goto out;
 821
 822                 /* packet is going to our gateway */
 823                 if (curr_gw->orig_node == orig_dst_node)
 824                         goto out;
 825
 826                 /* If the dhcp packet has been sent to a different gw,
 827                  * we have to evaluate whether the old gw is still
 828                  * reliable enough
 829                  */
 830                 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
 831                                                 NULL);
 832                 if (!neigh_curr)
 833                         goto out;
 834
 835                 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
 836                                                       BATADV_IF_DEFAULT);
 837                 if (!curr_ifinfo)
 838                         goto out;
 839
 840                 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
 841                 batadv_neigh_ifinfo_free_ref(curr_ifinfo);
 842
 843                 break;
 844         case BATADV_GW_MODE_OFF:
 845         default:
 846                 goto out;
 847         }
 848
 849         neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
 850         if (!neigh_old)
 851                 goto out;
 852
 853         old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
 854         if (!old_ifinfo)
 855                 goto out;
 856
 857         if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
 858                 out_of_range = true;
 859         batadv_neigh_ifinfo_free_ref(old_ifinfo);
 860
 861 out:
 862         if (orig_dst_node)
 863                 batadv_orig_node_free_ref(orig_dst_node);
 864         if (curr_gw)
 865                 batadv_gw_node_free_ref(curr_gw);
 866         if (gw_node)
 867                 batadv_gw_node_free_ref(gw_node);
 868         if (neigh_old)
 869                 batadv_neigh_node_free_ref(neigh_old);
 870         if (neigh_curr)
 871                 batadv_neigh_node_free_ref(neigh_curr);
 872         return out_of_range;
 873 }