net/batman-adv/gateway_client.c

   1 /* Copyright (C) 2009-2016  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 "gateway_client.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/byteorder/generic.h>
  23 #include <linux/etherdevice.h>
  24 #include <linux/fs.h>
  25 #include <linux/if_ether.h>
  26 #include <linux/if_vlan.h>
  27 #include <linux/in.h>
  28 #include <linux/ip.h>
  29 #include <linux/ipv6.h>
  30 #include <linux/kernel.h>
  31 #include <linux/kref.h>
  32 #include <linux/list.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/rculist.h>
  35 #include <linux/rcupdate.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/skbuff.h>
  38 #include <linux/slab.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/stddef.h>
  41 #include <linux/udp.h>
  42
  43 #include "gateway_common.h"
  44 #include "hard-interface.h"
  45 #include "originator.h"
  46 #include "packet.h"
  47 #include "routing.h"
  48 #include "sysfs.h"
  49 #include "translation-table.h"
  50
  51 /* These are the offsets of the "hw type" and "hw address length" in the dhcp
  52  * packet starting at the beginning of the dhcp header
  53  */
  54 #define BATADV_DHCP_HTYPE_OFFSET        1
  55 #define BATADV_DHCP_HLEN_OFFSET         2
  56 /* Value of htype representing Ethernet */
  57 #define BATADV_DHCP_HTYPE_ETHERNET      0x01
  58 /* This is the offset of the "chaddr" field in the dhcp packet starting at the
  59  * beginning of the dhcp header
  60  */
  61 #define BATADV_DHCP_CHADDR_OFFSET       28
  62
  63 /**
  64  * batadv_gw_node_release - release gw_node from lists and queue for free after
  65  *  rcu grace period
  66  * @ref: kref pointer of the gw_node
  67  */
  68 static void batadv_gw_node_release(struct kref *ref)
  69 {
  70         struct batadv_gw_node *gw_node;
  71
  72         gw_node = container_of(ref, struct batadv_gw_node, refcount);
  73
  74         batadv_orig_node_put(gw_node->orig_node);
  75         kfree_rcu(gw_node, rcu);
  76 }
  77
  78 /**
  79  * batadv_gw_node_put - decrement the gw_node refcounter and possibly release it
  80  * @gw_node: gateway node to free
  81  */
  82 static void batadv_gw_node_put(struct batadv_gw_node *gw_node)
  83 {
  84         kref_put(&gw_node->refcount, batadv_gw_node_release);
  85 }
  86
  87 static struct batadv_gw_node *
  88 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
  89 {
  90         struct batadv_gw_node *gw_node;
  91
  92         rcu_read_lock();
  93         gw_node = rcu_dereference(bat_priv->gw.curr_gw);
  94         if (!gw_node)
  95                 goto out;
  96
  97         if (!kref_get_unless_zero(&gw_node->refcount))
  98                 gw_node = NULL;
  99
 100 out:
 101         rcu_read_unlock();
 102         return gw_node;
 103 }
 104
 105 struct batadv_orig_node *
 106 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
 107 {
 108         struct batadv_gw_node *gw_node;
 109         struct batadv_orig_node *orig_node = NULL;
 110
 111         gw_node = batadv_gw_get_selected_gw_node(bat_priv);
 112         if (!gw_node)
 113                 goto out;
 114
 115         rcu_read_lock();
 116         orig_node = gw_node->orig_node;
 117         if (!orig_node)
 118                 goto unlock;
 119
 120         if (!kref_get_unless_zero(&orig_node->refcount))
 121                 orig_node = NULL;
 122
 123 unlock:
 124         rcu_read_unlock();
 125 out:
 126         if (gw_node)
 127                 batadv_gw_node_put(gw_node);
 128         return orig_node;
 129 }
 130
 131 static void batadv_gw_select(struct batadv_priv *bat_priv,
 132                              struct batadv_gw_node *new_gw_node)
 133 {
 134         struct batadv_gw_node *curr_gw_node;
 135
 136         spin_lock_bh(&bat_priv->gw.list_lock);
 137
 138         if (new_gw_node && !kref_get_unless_zero(&new_gw_node->refcount))
 139                 new_gw_node = NULL;
 140
 141         curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1);
 142         rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node);
 143
 144         if (curr_gw_node)
 145                 batadv_gw_node_put(curr_gw_node);
 146
 147         spin_unlock_bh(&bat_priv->gw.list_lock);
 148 }
 149
 150 /**
 151  * batadv_gw_reselect - force a gateway reselection
 152  * @bat_priv: the bat priv with all the soft interface information
 153  *
 154  * Set a flag to remind the GW component to perform a new gateway reselection.
 155  * However this function does not ensure that the current gateway is going to be
 156  * deselected. The reselection mechanism may elect the same gateway once again.
 157  *
 158  * This means that invoking batadv_gw_reselect() does not guarantee a gateway
 159  * change and therefore a uevent is not necessarily expected.
 160  */
 161 void batadv_gw_reselect(struct batadv_priv *bat_priv)
 162 {
 163         atomic_set(&bat_priv->gw.reselect, 1);
 164 }
 165
 166 static struct batadv_gw_node *
 167 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
 168 {
 169         struct batadv_neigh_node *router;
 170         struct batadv_neigh_ifinfo *router_ifinfo;
 171         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 172         u64 max_gw_factor = 0;
 173         u64 tmp_gw_factor = 0;
 174         u8 max_tq = 0;
 175         u8 tq_avg;
 176         struct batadv_orig_node *orig_node;
 177
 178         rcu_read_lock();
 179         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 180                 orig_node = gw_node->orig_node;
 181                 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 182                 if (!router)
 183                         continue;
 184
 185                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 186                                                         BATADV_IF_DEFAULT);
 187                 if (!router_ifinfo)
 188                         goto next;
 189
 190                 if (!kref_get_unless_zero(&gw_node->refcount))
 191                         goto next;
 192
 193                 tq_avg = router_ifinfo->bat_iv.tq_avg;
 194
 195                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 196                 case 1: /* fast connection */
 197                         tmp_gw_factor = tq_avg * tq_avg;
 198                         tmp_gw_factor *= gw_node->bandwidth_down;
 199                         tmp_gw_factor *= 100 * 100;
 200                         tmp_gw_factor >>= 18;
 201
 202                         if ((tmp_gw_factor > max_gw_factor) ||
 203                             ((tmp_gw_factor == max_gw_factor) &&
 204                              (tq_avg > max_tq))) {
 205                                 if (curr_gw)
 206                                         batadv_gw_node_put(curr_gw);
 207                                 curr_gw = gw_node;
 208                                 kref_get(&curr_gw->refcount);
 209                         }
 210                         break;
 211
 212                 default: /* 2:  stable connection (use best statistic)
 213                           * 3:  fast-switch (use best statistic but change as
 214                           *     soon as a better gateway appears)
 215                           * XX: late-switch (use best statistic but change as
 216                           *     soon as a better gateway appears which has
 217                           *     $routing_class more tq points)
 218                           */
 219                         if (tq_avg > max_tq) {
 220                                 if (curr_gw)
 221                                         batadv_gw_node_put(curr_gw);
 222                                 curr_gw = gw_node;
 223                                 kref_get(&curr_gw->refcount);
 224                         }
 225                         break;
 226                 }
 227
 228                 if (tq_avg > max_tq)
 229                         max_tq = tq_avg;
 230
 231                 if (tmp_gw_factor > max_gw_factor)
 232                         max_gw_factor = tmp_gw_factor;
 233
 234                 batadv_gw_node_put(gw_node);
 235
 236 next:
 237                 batadv_neigh_node_put(router);
 238                 if (router_ifinfo)
 239                         batadv_neigh_ifinfo_put(router_ifinfo);
 240         }
 241         rcu_read_unlock();
 242
 243         return curr_gw;
 244 }
 245
 246 /**
 247  * batadv_gw_check_client_stop - check if client mode has been switched off
 248  * @bat_priv: the bat priv with all the soft interface information
 249  *
 250  * This function assumes the caller has checked that the gw state *is actually
 251  * changing*. This function is not supposed to be called when there is no state
 252  * change.
 253  */
 254 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
 255 {
 256         struct batadv_gw_node *curr_gw;
 257
 258         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 259                 return;
 260
 261         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 262         if (!curr_gw)
 263                 return;
 264
 265         /* deselect the current gateway so that next time that client mode is
 266          * enabled a proper GW_ADD event can be sent
 267          */
 268         batadv_gw_select(bat_priv, NULL);
 269
 270         /* if batman-adv is switching the gw client mode off and a gateway was
 271          * already selected, send a DEL uevent
 272          */
 273         batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
 274
 275         batadv_gw_node_put(curr_gw);
 276 }
 277
 278 void batadv_gw_election(struct batadv_priv *bat_priv)
 279 {
 280         struct batadv_gw_node *curr_gw = NULL;
 281         struct batadv_gw_node *next_gw = NULL;
 282         struct batadv_neigh_node *router = NULL;
 283         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 284         char gw_addr[18] = { '\0' };
 285
 286         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 287                 goto out;
 288
 289         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 290
 291         if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
 292                 goto out;
 293
 294         next_gw = batadv_gw_get_best_gw_node(bat_priv);
 295
 296         if (curr_gw == next_gw)
 297                 goto out;
 298
 299         if (next_gw) {
 300                 sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
 301
 302                 router = batadv_orig_router_get(next_gw->orig_node,
 303                                                 BATADV_IF_DEFAULT);
 304                 if (!router) {
 305                         batadv_gw_reselect(bat_priv);
 306                         goto out;
 307                 }
 308
 309                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 310                                                         BATADV_IF_DEFAULT);
 311                 if (!router_ifinfo) {
 312                         batadv_gw_reselect(bat_priv);
 313                         goto out;
 314                 }
 315         }
 316
 317         if ((curr_gw) && (!next_gw)) {
 318                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 319                            "Removing selected gateway - no gateway in range\n");
 320                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
 321                                     NULL);
 322         } else if ((!curr_gw) && (next_gw)) {
 323                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 324                            "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 325                            next_gw->orig_node->orig,
 326                            next_gw->bandwidth_down / 10,
 327                            next_gw->bandwidth_down % 10,
 328                            next_gw->bandwidth_up / 10,
 329                            next_gw->bandwidth_up % 10,
 330                            router_ifinfo->bat_iv.tq_avg);
 331                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
 332                                     gw_addr);
 333         } else {
 334                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 335                            "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 336                            next_gw->orig_node->orig,
 337                            next_gw->bandwidth_down / 10,
 338                            next_gw->bandwidth_down % 10,
 339                            next_gw->bandwidth_up / 10,
 340                            next_gw->bandwidth_up % 10,
 341                            router_ifinfo->bat_iv.tq_avg);
 342                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
 343                                     gw_addr);
 344         }
 345
 346         batadv_gw_select(bat_priv, next_gw);
 347
 348 out:
 349         if (curr_gw)
 350                 batadv_gw_node_put(curr_gw);
 351         if (next_gw)
 352                 batadv_gw_node_put(next_gw);
 353         if (router)
 354                 batadv_neigh_node_put(router);
 355         if (router_ifinfo)
 356                 batadv_neigh_ifinfo_put(router_ifinfo);
 357 }
 358
 359 void batadv_gw_check_election(struct batadv_priv *bat_priv,
 360                               struct batadv_orig_node *orig_node)
 361 {
 362         struct batadv_neigh_ifinfo *router_orig_tq = NULL;
 363         struct batadv_neigh_ifinfo *router_gw_tq = NULL;
 364         struct batadv_orig_node *curr_gw_orig;
 365         struct batadv_neigh_node *router_gw = NULL;
 366         struct batadv_neigh_node *router_orig = NULL;
 367         u8 gw_tq_avg, orig_tq_avg;
 368
 369         curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 370         if (!curr_gw_orig)
 371                 goto reselect;
 372
 373         router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
 374         if (!router_gw)
 375                 goto reselect;
 376
 377         router_gw_tq = batadv_neigh_ifinfo_get(router_gw,
 378                                                BATADV_IF_DEFAULT);
 379         if (!router_gw_tq)
 380                 goto reselect;
 381
 382         /* this node already is the gateway */
 383         if (curr_gw_orig == orig_node)
 384                 goto out;
 385
 386         router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 387         if (!router_orig)
 388                 goto out;
 389
 390         router_orig_tq = batadv_neigh_ifinfo_get(router_orig,
 391                                                  BATADV_IF_DEFAULT);
 392         if (!router_orig_tq)
 393                 goto out;
 394
 395         gw_tq_avg = router_gw_tq->bat_iv.tq_avg;
 396         orig_tq_avg = router_orig_tq->bat_iv.tq_avg;
 397
 398         /* the TQ value has to be better */
 399         if (orig_tq_avg < gw_tq_avg)
 400                 goto out;
 401
 402         /* if the routing class is greater than 3 the value tells us how much
 403          * greater the TQ value of the new gateway must be
 404          */
 405         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 406             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 407                 goto out;
 408
 409         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 410                    "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
 411                    gw_tq_avg, orig_tq_avg);
 412
 413 reselect:
 414         batadv_gw_reselect(bat_priv);
 415 out:
 416         if (curr_gw_orig)
 417                 batadv_orig_node_put(curr_gw_orig);
 418         if (router_gw)
 419                 batadv_neigh_node_put(router_gw);
 420         if (router_orig)
 421                 batadv_neigh_node_put(router_orig);
 422         if (router_gw_tq)
 423                 batadv_neigh_ifinfo_put(router_gw_tq);
 424         if (router_orig_tq)
 425                 batadv_neigh_ifinfo_put(router_orig_tq);
 426 }
 427
 428 /**
 429  * batadv_gw_node_add - add gateway node to list of available gateways
 430  * @bat_priv: the bat priv with all the soft interface information
 431  * @orig_node: originator announcing gateway capabilities
 432  * @gateway: announced bandwidth information
 433  */
 434 static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 435                                struct batadv_orig_node *orig_node,
 436                                struct batadv_tvlv_gateway_data *gateway)
 437 {
 438         struct batadv_gw_node *gw_node;
 439
 440         if (gateway->bandwidth_down == 0)
 441                 return;
 442
 443         if (!kref_get_unless_zero(&orig_node->refcount))
 444                 return;
 445
 446         gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 447         if (!gw_node) {
 448                 batadv_orig_node_put(orig_node);
 449                 return;
 450         }
 451
 452         INIT_HLIST_NODE(&gw_node->list);
 453         gw_node->orig_node = orig_node;
 454         gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 455         gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 456         kref_init(&gw_node->refcount);
 457
 458         spin_lock_bh(&bat_priv->gw.list_lock);
 459         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list);
 460         spin_unlock_bh(&bat_priv->gw.list_lock);
 461
 462         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 463                    "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
 464                    orig_node->orig,
 465                    ntohl(gateway->bandwidth_down) / 10,
 466                    ntohl(gateway->bandwidth_down) % 10,
 467                    ntohl(gateway->bandwidth_up) / 10,
 468                    ntohl(gateway->bandwidth_up) % 10);
 469 }
 470
 471 /**
 472  * batadv_gw_node_get - retrieve gateway node from list of available gateways
 473  * @bat_priv: the bat priv with all the soft interface information
 474  * @orig_node: originator announcing gateway capabilities
 475  *
 476  * Return: gateway node if found or NULL otherwise.
 477  */
 478 static struct batadv_gw_node *
 479 batadv_gw_node_get(struct batadv_priv *bat_priv,
 480                    struct batadv_orig_node *orig_node)
 481 {
 482         struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
 483
 484         rcu_read_lock();
 485         hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) {
 486                 if (gw_node_tmp->orig_node != orig_node)
 487                         continue;
 488
 489                 if (!kref_get_unless_zero(&gw_node_tmp->refcount))
 490                         continue;
 491
 492                 gw_node = gw_node_tmp;
 493                 break;
 494         }
 495         rcu_read_unlock();
 496
 497         return gw_node;
 498 }
 499
 500 /**
 501  * batadv_gw_node_update - update list of available gateways with changed
 502  *  bandwidth information
 503  * @bat_priv: the bat priv with all the soft interface information
 504  * @orig_node: originator announcing gateway capabilities
 505  * @gateway: announced bandwidth information
 506  */
 507 void batadv_gw_node_update(struct batadv_priv *bat_priv,
 508                            struct batadv_orig_node *orig_node,
 509                            struct batadv_tvlv_gateway_data *gateway)
 510 {
 511         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 512
 513         gw_node = batadv_gw_node_get(bat_priv, orig_node);
 514         if (!gw_node) {
 515                 batadv_gw_node_add(bat_priv, orig_node, gateway);
 516                 goto out;
 517         }
 518
 519         if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) &&
 520             (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up)))
 521                 goto out;
 522
 523         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 524                    "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
 525                    orig_node->orig,
 526                    gw_node->bandwidth_down / 10,
 527                    gw_node->bandwidth_down % 10,
 528                    gw_node->bandwidth_up / 10,
 529                    gw_node->bandwidth_up % 10,
 530                    ntohl(gateway->bandwidth_down) / 10,
 531                    ntohl(gateway->bandwidth_down) % 10,
 532                    ntohl(gateway->bandwidth_up) / 10,
 533                    ntohl(gateway->bandwidth_up) % 10);
 534
 535         gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 536         gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 537
 538         if (ntohl(gateway->bandwidth_down) == 0) {
 539                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 540                            "Gateway %pM removed from gateway list\n",
 541                            orig_node->orig);
 542
 543                 /* Note: We don't need a NULL check here, since curr_gw never
 544                  * gets dereferenced.
 545                  */
 546                 spin_lock_bh(&bat_priv->gw.list_lock);
 547                 if (!hlist_unhashed(&gw_node->list)) {
 548                         hlist_del_init_rcu(&gw_node->list);
 549                         batadv_gw_node_put(gw_node);
 550                 }
 551                 spin_unlock_bh(&bat_priv->gw.list_lock);
 552
 553                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 554                 if (gw_node == curr_gw)
 555                         batadv_gw_reselect(bat_priv);
 556
 557                 if (curr_gw)
 558                         batadv_gw_node_put(curr_gw);
 559         }
 560
 561 out:
 562         if (gw_node)
 563                 batadv_gw_node_put(gw_node);
 564 }
 565
 566 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 567                            struct batadv_orig_node *orig_node)
 568 {
 569         struct batadv_tvlv_gateway_data gateway;
 570
 571         gateway.bandwidth_down = 0;
 572         gateway.bandwidth_up = 0;
 573
 574         batadv_gw_node_update(bat_priv, orig_node, &gateway);
 575 }
 576
 577 void batadv_gw_node_free(struct batadv_priv *bat_priv)
 578 {
 579         struct batadv_gw_node *gw_node;
 580         struct hlist_node *node_tmp;
 581
 582         spin_lock_bh(&bat_priv->gw.list_lock);
 583         hlist_for_each_entry_safe(gw_node, node_tmp,
 584                                   &bat_priv->gw.list, list) {
 585                 hlist_del_init_rcu(&gw_node->list);
 586                 batadv_gw_node_put(gw_node);
 587         }
 588         spin_unlock_bh(&bat_priv->gw.list_lock);
 589 }
 590
 591 /* fails if orig_node has no router */
 592 static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
 593                                     struct seq_file *seq,
 594                                     const struct batadv_gw_node *gw_node)
 595 {
 596         struct batadv_gw_node *curr_gw;
 597         struct batadv_neigh_node *router;
 598         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 599         int ret = -1;
 600
 601         router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
 602         if (!router)
 603                 goto out;
 604
 605         router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
 606         if (!router_ifinfo)
 607                 goto out;
 608
 609         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 610
 611         seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
 612                    (curr_gw == gw_node ? "=>" : "  "),
 613                    gw_node->orig_node->orig,
 614                    router_ifinfo->bat_iv.tq_avg, router->addr,
 615                    router->if_incoming->net_dev->name,
 616                    gw_node->bandwidth_down / 10,
 617                    gw_node->bandwidth_down % 10,
 618                    gw_node->bandwidth_up / 10,
 619                    gw_node->bandwidth_up % 10);
 620         ret = seq_has_overflowed(seq) ? -1 : 0;
 621
 622         if (curr_gw)
 623                 batadv_gw_node_put(curr_gw);
 624 out:
 625         if (router_ifinfo)
 626                 batadv_neigh_ifinfo_put(router_ifinfo);
 627         if (router)
 628                 batadv_neigh_node_put(router);
 629         return ret;
 630 }
 631
 632 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 633 {
 634         struct net_device *net_dev = (struct net_device *)seq->private;
 635         struct batadv_priv *bat_priv = netdev_priv(net_dev);
 636         struct batadv_hard_iface *primary_if;
 637         struct batadv_gw_node *gw_node;
 638         int gw_count = 0;
 639
 640         primary_if = batadv_seq_print_text_primary_if_get(seq);
 641         if (!primary_if)
 642                 goto out;
 643
 644         seq_printf(seq,
 645                    "      %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 646                    "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
 647                    BATADV_SOURCE_VERSION, primary_if->net_dev->name,
 648                    primary_if->net_dev->dev_addr, net_dev->name);
 649
 650         rcu_read_lock();
 651         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 652                 /* fails if orig_node has no router */
 653                 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
 654                         continue;
 655
 656                 gw_count++;
 657         }
 658         rcu_read_unlock();
 659
 660         if (gw_count == 0)
 661                 seq_puts(seq, "No gateways in range ...\n");
 662
 663 out:
 664         if (primary_if)
 665                 batadv_hardif_put(primary_if);
 666         return 0;
 667 }
 668
 669 /**
 670  * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message
 671  * @skb: the packet to check
 672  * @header_len: a pointer to the batman-adv header size
 673  * @chaddr: buffer where the client address will be stored. Valid
 674  *  only if the function returns BATADV_DHCP_TO_CLIENT
 675  *
 676  * This function may re-allocate the data buffer of the skb passed as argument.
 677  *
 678  * Return:
 679  * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
 680  *   while parsing it
 681  * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
 682  * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
 683  */
 684 enum batadv_dhcp_recipient
 685 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
 686                              u8 *chaddr)
 687 {
 688         enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
 689         struct ethhdr *ethhdr;
 690         struct iphdr *iphdr;
 691         struct ipv6hdr *ipv6hdr;
 692         struct udphdr *udphdr;
 693         struct vlan_ethhdr *vhdr;
 694         int chaddr_offset;
 695         __be16 proto;
 696         u8 *p;
 697
 698         /* check for ethernet header */
 699         if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
 700                 return BATADV_DHCP_NO;
 701
 702         ethhdr = eth_hdr(skb);
 703         proto = ethhdr->h_proto;
 704         *header_len += ETH_HLEN;
 705
 706         /* check for initial vlan header */
 707         if (proto == htons(ETH_P_8021Q)) {
 708                 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
 709                         return BATADV_DHCP_NO;
 710
 711                 vhdr = vlan_eth_hdr(skb);
 712                 proto = vhdr->h_vlan_encapsulated_proto;
 713                 *header_len += VLAN_HLEN;
 714         }
 715
 716         /* check for ip header */
 717         switch (proto) {
 718         case htons(ETH_P_IP):
 719                 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
 720                         return BATADV_DHCP_NO;
 721
 722                 iphdr = (struct iphdr *)(skb->data + *header_len);
 723                 *header_len += iphdr->ihl * 4;
 724
 725                 /* check for udp header */
 726                 if (iphdr->protocol != IPPROTO_UDP)
 727                         return BATADV_DHCP_NO;
 728
 729                 break;
 730         case htons(ETH_P_IPV6):
 731                 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
 732                         return BATADV_DHCP_NO;
 733
 734                 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
 735                 *header_len += sizeof(*ipv6hdr);
 736
 737                 /* check for udp header */
 738                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 739                         return BATADV_DHCP_NO;
 740
 741                 break;
 742         default:
 743                 return BATADV_DHCP_NO;
 744         }
 745
 746         if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
 747                 return BATADV_DHCP_NO;
 748
 749         udphdr = (struct udphdr *)(skb->data + *header_len);
 750         *header_len += sizeof(*udphdr);
 751
 752         /* check for bootp port */
 753         switch (proto) {
 754         case htons(ETH_P_IP):
 755                 if (udphdr->dest == htons(67))
 756                         ret = BATADV_DHCP_TO_SERVER;
 757                 else if (udphdr->source == htons(67))
 758                         ret = BATADV_DHCP_TO_CLIENT;
 759                 break;
 760         case htons(ETH_P_IPV6):
 761                 if (udphdr->dest == htons(547))
 762                         ret = BATADV_DHCP_TO_SERVER;
 763                 else if (udphdr->source == htons(547))
 764                         ret = BATADV_DHCP_TO_CLIENT;
 765                 break;
 766         }
 767
 768         chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
 769         /* store the client address if the message is going to a client */
 770         if (ret == BATADV_DHCP_TO_CLIENT &&
 771             pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) {
 772                 /* check if the DHCP packet carries an Ethernet DHCP */
 773                 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
 774                 if (*p != BATADV_DHCP_HTYPE_ETHERNET)
 775                         return BATADV_DHCP_NO;
 776
 777                 /* check if the DHCP packet carries a valid Ethernet address */
 778                 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
 779                 if (*p != ETH_ALEN)
 780                         return BATADV_DHCP_NO;
 781
 782                 ether_addr_copy(chaddr, skb->data + chaddr_offset);
 783         }
 784
 785         return ret;
 786 }
 787
 788 /**
 789  * batadv_gw_out_of_range - check if the dhcp request destination is the best gw
 790  * @bat_priv: the bat priv with all the soft interface information
 791  * @skb: the outgoing packet
 792  *
 793  * Check if the skb is a DHCP request and if it is sent to the current best GW
 794  * server. Due to topology changes it may be the case that the GW server
 795  * previously selected is not the best one anymore.
 796  *
 797  * This call might reallocate skb data.
 798  * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
 799  *
 800  * Return: true if the packet destination is unicast and it is not the best gw,
 801  * false otherwise.
 802  */
 803 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 804                             struct sk_buff *skb)
 805 {
 806         struct batadv_neigh_node *neigh_curr = NULL;
 807         struct batadv_neigh_node *neigh_old = NULL;
 808         struct batadv_orig_node *orig_dst_node = NULL;
 809         struct batadv_gw_node *gw_node = NULL;
 810         struct batadv_gw_node *curr_gw = NULL;
 811         struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
 812         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 813         bool out_of_range = false;
 814         u8 curr_tq_avg;
 815         unsigned short vid;
 816
 817         vid = batadv_get_vid(skb, 0);
 818
 819         orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
 820                                                  ethhdr->h_dest, vid);
 821         if (!orig_dst_node)
 822                 goto out;
 823
 824         gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
 825         if (!gw_node)
 826                 goto out;
 827
 828         switch (atomic_read(&bat_priv->gw_mode)) {
 829         case BATADV_GW_MODE_SERVER:
 830                 /* If we are a GW then we are our best GW. We can artificially
 831                  * set the tq towards ourself as the maximum value
 832                  */
 833                 curr_tq_avg = BATADV_TQ_MAX_VALUE;
 834                 break;
 835         case BATADV_GW_MODE_CLIENT:
 836                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 837                 if (!curr_gw)
 838                         goto out;
 839
 840                 /* packet is going to our gateway */
 841                 if (curr_gw->orig_node == orig_dst_node)
 842                         goto out;
 843
 844                 /* If the dhcp packet has been sent to a different gw,
 845                  * we have to evaluate whether the old gw is still
 846                  * reliable enough
 847                  */
 848                 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
 849                                                 NULL);
 850                 if (!neigh_curr)
 851                         goto out;
 852
 853                 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
 854                                                       BATADV_IF_DEFAULT);
 855                 if (!curr_ifinfo)
 856                         goto out;
 857
 858                 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
 859                 batadv_neigh_ifinfo_put(curr_ifinfo);
 860
 861                 break;
 862         case BATADV_GW_MODE_OFF:
 863         default:
 864                 goto out;
 865         }
 866
 867         neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
 868         if (!neigh_old)
 869                 goto out;
 870
 871         old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
 872         if (!old_ifinfo)
 873                 goto out;
 874
 875         if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
 876                 out_of_range = true;
 877         batadv_neigh_ifinfo_put(old_ifinfo);
 878
 879 out:
 880         if (orig_dst_node)
 881                 batadv_orig_node_put(orig_dst_node);
 882         if (curr_gw)
 883                 batadv_gw_node_put(curr_gw);
 884         if (gw_node)
 885                 batadv_gw_node_put(gw_node);
 886         if (neigh_old)
 887                 batadv_neigh_node_put(neigh_old);
 888         if (neigh_curr)
 889                 batadv_neigh_node_put(neigh_curr);
 890         return out_of_range;
 891 }