kernel/net/batman-adv/gateway_client.c

   1 /* Copyright (C) 2009-2014 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                 batadv_orig_node_free_ref(gw_node->orig_node);
  47                 kfree_rcu(gw_node, rcu);
  48         }
  49 }
  50
  51 static struct batadv_gw_node *
  52 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
  53 {
  54         struct batadv_gw_node *gw_node;
  55
  56         rcu_read_lock();
  57         gw_node = rcu_dereference(bat_priv->gw.curr_gw);
  58         if (!gw_node)
  59                 goto out;
  60
  61         if (!atomic_inc_not_zero(&gw_node->refcount))
  62                 gw_node = NULL;
  63
  64 out:
  65         rcu_read_unlock();
  66         return gw_node;
  67 }
  68
  69 struct batadv_orig_node *
  70 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
  71 {
  72         struct batadv_gw_node *gw_node;
  73         struct batadv_orig_node *orig_node = NULL;
  74
  75         gw_node = batadv_gw_get_selected_gw_node(bat_priv);
  76         if (!gw_node)
  77                 goto out;
  78
  79         rcu_read_lock();
  80         orig_node = gw_node->orig_node;
  81         if (!orig_node)
  82                 goto unlock;
  83
  84         if (!atomic_inc_not_zero(&orig_node->refcount))
  85                 orig_node = NULL;
  86
  87 unlock:
  88         rcu_read_unlock();
  89 out:
  90         if (gw_node)
  91                 batadv_gw_node_free_ref(gw_node);
  92         return orig_node;
  93 }
  94
  95 static void batadv_gw_select(struct batadv_priv *bat_priv,
  96                              struct batadv_gw_node *new_gw_node)
  97 {
  98         struct batadv_gw_node *curr_gw_node;
  99
 100         spin_lock_bh(&bat_priv->gw.list_lock);
 101
 102         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
 103                 new_gw_node = NULL;
 104
 105         curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1);
 106         rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node);
 107
 108         if (curr_gw_node)
 109                 batadv_gw_node_free_ref(curr_gw_node);
 110
 111         spin_unlock_bh(&bat_priv->gw.list_lock);
 112 }
 113
 114 /**
 115  * batadv_gw_reselect - force a gateway reselection
 116  * @bat_priv: the bat priv with all the soft interface information
 117  *
 118  * Set a flag to remind the GW component to perform a new gateway reselection.
 119  * However this function does not ensure that the current gateway is going to be
 120  * deselected. The reselection mechanism may elect the same gateway once again.
 121  *
 122  * This means that invoking batadv_gw_reselect() does not guarantee a gateway
 123  * change and therefore a uevent is not necessarily expected.
 124  */
 125 void batadv_gw_reselect(struct batadv_priv *bat_priv)
 126 {
 127         atomic_set(&bat_priv->gw.reselect, 1);
 128 }
 129
 130 static struct batadv_gw_node *
 131 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
 132 {
 133         struct batadv_neigh_node *router;
 134         struct batadv_neigh_ifinfo *router_ifinfo;
 135         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 136         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 137         uint32_t gw_divisor;
 138         uint8_t max_tq = 0;
 139         uint8_t tq_avg;
 140         struct batadv_orig_node *orig_node;
 141
 142         gw_divisor = BATADV_TQ_LOCAL_WINDOW_SIZE * BATADV_TQ_LOCAL_WINDOW_SIZE;
 143         gw_divisor *= 64;
 144
 145         rcu_read_lock();
 146         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 147                 if (gw_node->deleted)
 148                         continue;
 149
 150                 orig_node = gw_node->orig_node;
 151                 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 152                 if (!router)
 153                         continue;
 154
 155                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 156                                                         BATADV_IF_DEFAULT);
 157                 if (!router_ifinfo)
 158                         goto next;
 159
 160                 if (!atomic_inc_not_zero(&gw_node->refcount))
 161                         goto next;
 162
 163                 tq_avg = router_ifinfo->bat_iv.tq_avg;
 164
 165                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 166                 case 1: /* fast connection */
 167                         tmp_gw_factor = tq_avg * tq_avg;
 168                         tmp_gw_factor *= gw_node->bandwidth_down;
 169                         tmp_gw_factor *= 100 * 100;
 170                         tmp_gw_factor /= gw_divisor;
 171
 172                         if ((tmp_gw_factor > max_gw_factor) ||
 173                             ((tmp_gw_factor == max_gw_factor) &&
 174                              (tq_avg > max_tq))) {
 175                                 if (curr_gw)
 176                                         batadv_gw_node_free_ref(curr_gw);
 177                                 curr_gw = gw_node;
 178                                 atomic_inc(&curr_gw->refcount);
 179                         }
 180                         break;
 181
 182                 default: /* 2:  stable connection (use best statistic)
 183                           * 3:  fast-switch (use best statistic but change as
 184                           *     soon as a better gateway appears)
 185                           * XX: late-switch (use best statistic but change as
 186                           *     soon as a better gateway appears which has
 187                           *     $routing_class more tq points)
 188                           */
 189                         if (tq_avg > max_tq) {
 190                                 if (curr_gw)
 191                                         batadv_gw_node_free_ref(curr_gw);
 192                                 curr_gw = gw_node;
 193                                 atomic_inc(&curr_gw->refcount);
 194                         }
 195                         break;
 196                 }
 197
 198                 if (tq_avg > max_tq)
 199                         max_tq = tq_avg;
 200
 201                 if (tmp_gw_factor > max_gw_factor)
 202                         max_gw_factor = tmp_gw_factor;
 203
 204                 batadv_gw_node_free_ref(gw_node);
 205
 206 next:
 207                 batadv_neigh_node_free_ref(router);
 208                 if (router_ifinfo)
 209                         batadv_neigh_ifinfo_free_ref(router_ifinfo);
 210         }
 211         rcu_read_unlock();
 212
 213         return curr_gw;
 214 }
 215
 216 /**
 217  * batadv_gw_check_client_stop - check if client mode has been switched off
 218  * @bat_priv: the bat priv with all the soft interface information
 219  *
 220  * This function assumes the caller has checked that the gw state *is actually
 221  * changing*. This function is not supposed to be called when there is no state
 222  * change.
 223  */
 224 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
 225 {
 226         struct batadv_gw_node *curr_gw;
 227
 228         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 229                 return;
 230
 231         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 232         if (!curr_gw)
 233                 return;
 234
 235         /* deselect the current gateway so that next time that client mode is
 236          * enabled a proper GW_ADD event can be sent
 237          */
 238         batadv_gw_select(bat_priv, NULL);
 239
 240         /* if batman-adv is switching the gw client mode off and a gateway was
 241          * already selected, send a DEL uevent
 242          */
 243         batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
 244
 245         batadv_gw_node_free_ref(curr_gw);
 246 }
 247
 248 void batadv_gw_election(struct batadv_priv *bat_priv)
 249 {
 250         struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL;
 251         struct batadv_neigh_node *router = NULL;
 252         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 253         char gw_addr[18] = { '\0' };
 254
 255         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 256                 goto out;
 257
 258         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 259
 260         if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
 261                 goto out;
 262
 263         next_gw = batadv_gw_get_best_gw_node(bat_priv);
 264
 265         if (curr_gw == next_gw)
 266                 goto out;
 267
 268         if (next_gw) {
 269                 sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
 270
 271                 router = batadv_orig_router_get(next_gw->orig_node,
 272                                                 BATADV_IF_DEFAULT);
 273                 if (!router) {
 274                         batadv_gw_reselect(bat_priv);
 275                         goto out;
 276                 }
 277
 278                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 279                                                         BATADV_IF_DEFAULT);
 280                 if (!router_ifinfo) {
 281                         batadv_gw_reselect(bat_priv);
 282                         goto out;
 283                 }
 284         }
 285
 286         if ((curr_gw) && (!next_gw)) {
 287                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 288                            "Removing selected gateway - no gateway in range\n");
 289                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
 290                                     NULL);
 291         } else if ((!curr_gw) && (next_gw)) {
 292                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 293                            "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 294                            next_gw->orig_node->orig,
 295                            next_gw->bandwidth_down / 10,
 296                            next_gw->bandwidth_down % 10,
 297                            next_gw->bandwidth_up / 10,
 298                            next_gw->bandwidth_up % 10,
 299                            router_ifinfo->bat_iv.tq_avg);
 300                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
 301                                     gw_addr);
 302         } else {
 303                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 304                            "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 305                            next_gw->orig_node->orig,
 306                            next_gw->bandwidth_down / 10,
 307                            next_gw->bandwidth_down % 10,
 308                            next_gw->bandwidth_up / 10,
 309                            next_gw->bandwidth_up % 10,
 310                            router_ifinfo->bat_iv.tq_avg);
 311                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
 312                                     gw_addr);
 313         }
 314
 315         batadv_gw_select(bat_priv, next_gw);
 316
 317 out:
 318         if (curr_gw)
 319                 batadv_gw_node_free_ref(curr_gw);
 320         if (next_gw)
 321                 batadv_gw_node_free_ref(next_gw);
 322         if (router)
 323                 batadv_neigh_node_free_ref(router);
 324         if (router_ifinfo)
 325                 batadv_neigh_ifinfo_free_ref(router_ifinfo);
 326 }
 327
 328 void batadv_gw_check_election(struct batadv_priv *bat_priv,
 329                               struct batadv_orig_node *orig_node)
 330 {
 331         struct batadv_neigh_ifinfo *router_orig_tq = NULL;
 332         struct batadv_neigh_ifinfo *router_gw_tq = NULL;
 333         struct batadv_orig_node *curr_gw_orig;
 334         struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL;
 335         uint8_t gw_tq_avg, orig_tq_avg;
 336
 337         curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 338         if (!curr_gw_orig)
 339                 goto reselect;
 340
 341         router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
 342         if (!router_gw)
 343                 goto reselect;
 344
 345         router_gw_tq = batadv_neigh_ifinfo_get(router_gw,
 346                                                BATADV_IF_DEFAULT);
 347         if (!router_gw_tq)
 348                 goto reselect;
 349
 350         /* this node already is the gateway */
 351         if (curr_gw_orig == orig_node)
 352                 goto out;
 353
 354         router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 355         if (!router_orig)
 356                 goto out;
 357
 358         router_orig_tq = batadv_neigh_ifinfo_get(router_orig,
 359                                                  BATADV_IF_DEFAULT);
 360         if (!router_orig_tq)
 361                 goto out;
 362
 363         gw_tq_avg = router_gw_tq->bat_iv.tq_avg;
 364         orig_tq_avg = router_orig_tq->bat_iv.tq_avg;
 365
 366         /* the TQ value has to be better */
 367         if (orig_tq_avg < gw_tq_avg)
 368                 goto out;
 369
 370         /* if the routing class is greater than 3 the value tells us how much
 371          * greater the TQ value of the new gateway must be
 372          */
 373         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 374             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 375                 goto out;
 376
 377         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 378                    "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
 379                    gw_tq_avg, orig_tq_avg);
 380
 381 reselect:
 382         batadv_gw_reselect(bat_priv);
 383 out:
 384         if (curr_gw_orig)
 385                 batadv_orig_node_free_ref(curr_gw_orig);
 386         if (router_gw)
 387                 batadv_neigh_node_free_ref(router_gw);
 388         if (router_orig)
 389                 batadv_neigh_node_free_ref(router_orig);
 390         if (router_gw_tq)
 391                 batadv_neigh_ifinfo_free_ref(router_gw_tq);
 392         if (router_orig_tq)
 393                 batadv_neigh_ifinfo_free_ref(router_orig_tq);
 394 }
 395
 396 /**
 397  * batadv_gw_node_add - add gateway node to list of available gateways
 398  * @bat_priv: the bat priv with all the soft interface information
 399  * @orig_node: originator announcing gateway capabilities
 400  * @gateway: announced bandwidth information
 401  */
 402 static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 403                                struct batadv_orig_node *orig_node,
 404                                struct batadv_tvlv_gateway_data *gateway)
 405 {
 406         struct batadv_gw_node *gw_node;
 407
 408         if (gateway->bandwidth_down == 0)
 409                 return;
 410
 411         if (!atomic_inc_not_zero(&orig_node->refcount))
 412                 return;
 413
 414         gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 415         if (!gw_node) {
 416                 batadv_orig_node_free_ref(orig_node);
 417                 return;
 418         }
 419
 420         INIT_HLIST_NODE(&gw_node->list);
 421         gw_node->orig_node = orig_node;
 422         atomic_set(&gw_node->refcount, 1);
 423
 424         spin_lock_bh(&bat_priv->gw.list_lock);
 425         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list);
 426         spin_unlock_bh(&bat_priv->gw.list_lock);
 427
 428         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 429                    "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
 430                    orig_node->orig,
 431                    ntohl(gateway->bandwidth_down) / 10,
 432                    ntohl(gateway->bandwidth_down) % 10,
 433                    ntohl(gateway->bandwidth_up) / 10,
 434                    ntohl(gateway->bandwidth_up) % 10);
 435 }
 436
 437 /**
 438  * batadv_gw_node_get - retrieve gateway node from list of available gateways
 439  * @bat_priv: the bat priv with all the soft interface information
 440  * @orig_node: originator announcing gateway capabilities
 441  *
 442  * Returns gateway node if found or NULL otherwise.
 443  */
 444 static struct batadv_gw_node *
 445 batadv_gw_node_get(struct batadv_priv *bat_priv,
 446                    struct batadv_orig_node *orig_node)
 447 {
 448         struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
 449
 450         rcu_read_lock();
 451         hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) {
 452                 if (gw_node_tmp->orig_node != orig_node)
 453                         continue;
 454
 455                 if (gw_node_tmp->deleted)
 456                         continue;
 457
 458                 if (!atomic_inc_not_zero(&gw_node_tmp->refcount))
 459                         continue;
 460
 461                 gw_node = gw_node_tmp;
 462                 break;
 463         }
 464         rcu_read_unlock();
 465
 466         return gw_node;
 467 }
 468
 469 /**
 470  * batadv_gw_node_update - update list of available gateways with changed
 471  *  bandwidth information
 472  * @bat_priv: the bat priv with all the soft interface information
 473  * @orig_node: originator announcing gateway capabilities
 474  * @gateway: announced bandwidth information
 475  */
 476 void batadv_gw_node_update(struct batadv_priv *bat_priv,
 477                            struct batadv_orig_node *orig_node,
 478                            struct batadv_tvlv_gateway_data *gateway)
 479 {
 480         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 481
 482         gw_node = batadv_gw_node_get(bat_priv, orig_node);
 483         if (!gw_node) {
 484                 batadv_gw_node_add(bat_priv, orig_node, gateway);
 485                 goto out;
 486         }
 487
 488         if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) &&
 489             (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up)))
 490                 goto out;
 491
 492         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 493                    "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
 494                    orig_node->orig,
 495                    gw_node->bandwidth_down / 10,
 496                    gw_node->bandwidth_down % 10,
 497                    gw_node->bandwidth_up / 10,
 498                    gw_node->bandwidth_up % 10,
 499                    ntohl(gateway->bandwidth_down) / 10,
 500                    ntohl(gateway->bandwidth_down) % 10,
 501                    ntohl(gateway->bandwidth_up) / 10,
 502                    ntohl(gateway->bandwidth_up) % 10);
 503
 504         gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 505         gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 506
 507         gw_node->deleted = 0;
 508         if (ntohl(gateway->bandwidth_down) == 0) {
 509                 gw_node->deleted = jiffies;
 510                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 511                            "Gateway %pM removed from gateway list\n",
 512                            orig_node->orig);
 513
 514                 /* Note: We don't need a NULL check here, since curr_gw never
 515                  * gets dereferenced.
 516                  */
 517                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 518                 if (gw_node == curr_gw)
 519                         batadv_gw_reselect(bat_priv);
 520         }
 521
 522 out:
 523         if (curr_gw)
 524                 batadv_gw_node_free_ref(curr_gw);
 525         if (gw_node)
 526                 batadv_gw_node_free_ref(gw_node);
 527 }
 528
 529 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 530                            struct batadv_orig_node *orig_node)
 531 {
 532         struct batadv_tvlv_gateway_data gateway;
 533
 534         gateway.bandwidth_down = 0;
 535         gateway.bandwidth_up = 0;
 536
 537         batadv_gw_node_update(bat_priv, orig_node, &gateway);
 538 }
 539
 540 void batadv_gw_node_purge(struct batadv_priv *bat_priv)
 541 {
 542         struct batadv_gw_node *gw_node, *curr_gw;
 543         struct hlist_node *node_tmp;
 544         unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT);
 545         int do_reselect = 0;
 546
 547         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 548
 549         spin_lock_bh(&bat_priv->gw.list_lock);
 550
 551         hlist_for_each_entry_safe(gw_node, node_tmp,
 552                                   &bat_priv->gw.list, list) {
 553                 if (((!gw_node->deleted) ||
 554                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 555                     atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE)
 556                         continue;
 557
 558                 if (curr_gw == gw_node)
 559                         do_reselect = 1;
 560
 561                 hlist_del_rcu(&gw_node->list);
 562                 batadv_gw_node_free_ref(gw_node);
 563         }
 564
 565         spin_unlock_bh(&bat_priv->gw.list_lock);
 566
 567         /* gw_reselect() needs to acquire the gw_list_lock */
 568         if (do_reselect)
 569                 batadv_gw_reselect(bat_priv);
 570
 571         if (curr_gw)
 572                 batadv_gw_node_free_ref(curr_gw);
 573 }
 574
 575 /* fails if orig_node has no router */
 576 static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
 577                                     struct seq_file *seq,
 578                                     const struct batadv_gw_node *gw_node)
 579 {
 580         struct batadv_gw_node *curr_gw;
 581         struct batadv_neigh_node *router;
 582         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 583         int ret = -1;
 584
 585         router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
 586         if (!router)
 587                 goto out;
 588
 589         router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
 590         if (!router_ifinfo)
 591                 goto out;
 592
 593         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 594
 595         seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
 596                    (curr_gw == gw_node ? "=>" : "  "),
 597                    gw_node->orig_node->orig,
 598                    router_ifinfo->bat_iv.tq_avg, router->addr,
 599                    router->if_incoming->net_dev->name,
 600                    gw_node->bandwidth_down / 10,
 601                    gw_node->bandwidth_down % 10,
 602                    gw_node->bandwidth_up / 10,
 603                    gw_node->bandwidth_up % 10);
 604         ret = seq_has_overflowed(seq) ? -1 : 0;
 605
 606         if (curr_gw)
 607                 batadv_gw_node_free_ref(curr_gw);
 608 out:
 609         if (router_ifinfo)
 610                 batadv_neigh_ifinfo_free_ref(router_ifinfo);
 611         if (router)
 612                 batadv_neigh_node_free_ref(router);
 613         return ret;
 614 }
 615
 616 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 617 {
 618         struct net_device *net_dev = (struct net_device *)seq->private;
 619         struct batadv_priv *bat_priv = netdev_priv(net_dev);
 620         struct batadv_hard_iface *primary_if;
 621         struct batadv_gw_node *gw_node;
 622         int gw_count = 0;
 623
 624         primary_if = batadv_seq_print_text_primary_if_get(seq);
 625         if (!primary_if)
 626                 goto out;
 627
 628         seq_printf(seq,
 629                    "      %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 630                    "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
 631                    BATADV_SOURCE_VERSION, primary_if->net_dev->name,
 632                    primary_if->net_dev->dev_addr, net_dev->name);
 633
 634         rcu_read_lock();
 635         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 636                 if (gw_node->deleted)
 637                         continue;
 638
 639                 /* fails if orig_node has no router */
 640                 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
 641                         continue;
 642
 643                 gw_count++;
 644         }
 645         rcu_read_unlock();
 646
 647         if (gw_count == 0)
 648                 seq_puts(seq, "No gateways in range ...\n");
 649
 650 out:
 651         if (primary_if)
 652                 batadv_hardif_free_ref(primary_if);
 653         return 0;
 654 }
 655
 656 /**
 657  * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message
 658  * @skb: the packet to check
 659  * @header_len: a pointer to the batman-adv header size
 660  * @chaddr: buffer where the client address will be stored. Valid
 661  *  only if the function returns BATADV_DHCP_TO_CLIENT
 662  *
 663  * Returns:
 664  * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
 665  *   while parsing it
 666  * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
 667  * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
 668  *
 669  * This function may re-allocate the data buffer of the skb passed as argument.
 670  */
 671 enum batadv_dhcp_recipient
 672 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
 673                              uint8_t *chaddr)
 674 {
 675         enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
 676         struct ethhdr *ethhdr;
 677         struct iphdr *iphdr;
 678         struct ipv6hdr *ipv6hdr;
 679         struct udphdr *udphdr;
 680         struct vlan_ethhdr *vhdr;
 681         int chaddr_offset;
 682         __be16 proto;
 683         uint8_t *p;
 684
 685         /* check for ethernet header */
 686         if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
 687                 return BATADV_DHCP_NO;
 688
 689         ethhdr = eth_hdr(skb);
 690         proto = ethhdr->h_proto;
 691         *header_len += ETH_HLEN;
 692
 693         /* check for initial vlan header */
 694         if (proto == htons(ETH_P_8021Q)) {
 695                 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
 696                         return BATADV_DHCP_NO;
 697
 698                 vhdr = vlan_eth_hdr(skb);
 699                 proto = vhdr->h_vlan_encapsulated_proto;
 700                 *header_len += VLAN_HLEN;
 701         }
 702
 703         /* check for ip header */
 704         switch (proto) {
 705         case htons(ETH_P_IP):
 706                 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
 707                         return BATADV_DHCP_NO;
 708
 709                 iphdr = (struct iphdr *)(skb->data + *header_len);
 710                 *header_len += iphdr->ihl * 4;
 711
 712                 /* check for udp header */
 713                 if (iphdr->protocol != IPPROTO_UDP)
 714                         return BATADV_DHCP_NO;
 715
 716                 break;
 717         case htons(ETH_P_IPV6):
 718                 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
 719                         return BATADV_DHCP_NO;
 720
 721                 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
 722                 *header_len += sizeof(*ipv6hdr);
 723
 724                 /* check for udp header */
 725                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 726                         return BATADV_DHCP_NO;
 727
 728                 break;
 729         default:
 730                 return BATADV_DHCP_NO;
 731         }
 732
 733         if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
 734                 return BATADV_DHCP_NO;
 735
 736         /* skb->data might have been reallocated by pskb_may_pull() */
 737         ethhdr = eth_hdr(skb);
 738         if (ntohs(ethhdr->h_proto) == ETH_P_8021Q)
 739                 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 740
 741         udphdr = (struct udphdr *)(skb->data + *header_len);
 742         *header_len += sizeof(*udphdr);
 743
 744         /* check for bootp port */
 745         switch (proto) {
 746         case htons(ETH_P_IP):
 747                 if (udphdr->dest == htons(67))
 748                         ret = BATADV_DHCP_TO_SERVER;
 749                 else if (udphdr->source == htons(67))
 750                         ret = BATADV_DHCP_TO_CLIENT;
 751                 break;
 752         case htons(ETH_P_IPV6):
 753                 if (udphdr->dest == htons(547))
 754                         ret = BATADV_DHCP_TO_SERVER;
 755                 else if (udphdr->source == htons(547))
 756                         ret = BATADV_DHCP_TO_CLIENT;
 757                 break;
 758         }
 759
 760         chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
 761         /* store the client address if the message is going to a client */
 762         if (ret == BATADV_DHCP_TO_CLIENT &&
 763             pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) {
 764                 /* check if the DHCP packet carries an Ethernet DHCP */
 765                 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
 766                 if (*p != BATADV_DHCP_HTYPE_ETHERNET)
 767                         return BATADV_DHCP_NO;
 768
 769                 /* check if the DHCP packet carries a valid Ethernet address */
 770                 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
 771                 if (*p != ETH_ALEN)
 772                         return BATADV_DHCP_NO;
 773
 774                 ether_addr_copy(chaddr, skb->data + chaddr_offset);
 775         }
 776
 777         return ret;
 778 }
 779
 780 /**
 781  * batadv_gw_out_of_range - check if the dhcp request destination is the best gw
 782  * @bat_priv: the bat priv with all the soft interface information
 783  * @skb: the outgoing packet
 784  *
 785  * Check if the skb is a DHCP request and if it is sent to the current best GW
 786  * server. Due to topology changes it may be the case that the GW server
 787  * previously selected is not the best one anymore.
 788  *
 789  * Returns true if the packet destination is unicast and it is not the best gw,
 790  * false otherwise.
 791  *
 792  * This call might reallocate skb data.
 793  * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
 794  */
 795 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 796                             struct sk_buff *skb)
 797 {
 798         struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL;
 799         struct batadv_orig_node *orig_dst_node = NULL;
 800         struct batadv_gw_node *gw_node = NULL, *curr_gw = NULL;
 801         struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
 802         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 803         bool out_of_range = false;
 804         uint8_t curr_tq_avg;
 805         unsigned short vid;
 806
 807         vid = batadv_get_vid(skb, 0);
 808
 809         orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
 810                                                  ethhdr->h_dest, vid);
 811         if (!orig_dst_node)
 812                 goto out;
 813
 814         gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
 815         if (!gw_node)
 816                 goto out;
 817
 818         switch (atomic_read(&bat_priv->gw_mode)) {
 819         case BATADV_GW_MODE_SERVER:
 820                 /* If we are a GW then we are our best GW. We can artificially
 821                  * set the tq towards ourself as the maximum value
 822                  */
 823                 curr_tq_avg = BATADV_TQ_MAX_VALUE;
 824                 break;
 825         case BATADV_GW_MODE_CLIENT:
 826                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 827                 if (!curr_gw)
 828                         goto out;
 829
 830                 /* packet is going to our gateway */
 831                 if (curr_gw->orig_node == orig_dst_node)
 832                         goto out;
 833
 834                 /* If the dhcp packet has been sent to a different gw,
 835                  * we have to evaluate whether the old gw is still
 836                  * reliable enough
 837                  */
 838                 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
 839                                                 NULL);
 840                 if (!neigh_curr)
 841                         goto out;
 842
 843                 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
 844                                                       BATADV_IF_DEFAULT);
 845                 if (!curr_ifinfo)
 846                         goto out;
 847
 848                 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
 849                 batadv_neigh_ifinfo_free_ref(curr_ifinfo);
 850
 851                 break;
 852         case BATADV_GW_MODE_OFF:
 853         default:
 854                 goto out;
 855         }
 856
 857         neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
 858         if (!neigh_old)
 859                 goto out;
 860
 861         old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
 862         if (!old_ifinfo)
 863                 goto out;
 864
 865         if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
 866                 out_of_range = true;
 867         batadv_neigh_ifinfo_free_ref(old_ifinfo);
 868
 869 out:
 870         if (orig_dst_node)
 871                 batadv_orig_node_free_ref(orig_dst_node);
 872         if (curr_gw)
 873                 batadv_gw_node_free_ref(curr_gw);
 874         if (gw_node)
 875                 batadv_gw_node_free_ref(gw_node);
 876         if (neigh_old)
 877                 batadv_neigh_node_free_ref(neigh_old);
 878         if (neigh_curr)
 879                 batadv_neigh_node_free_ref(neigh_curr);
 880         return out_of_range;
 881 }