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