net/batman-adv/gateway_client.c

   1 /* Copyright (C) 2009-2015 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/jiffies.h>
  31 #include <linux/kernel.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 static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
  64 {
  65         if (atomic_dec_and_test(&gw_node->refcount)) {
  66                 batadv_orig_node_free_ref(gw_node->orig_node);
  67                 kfree_rcu(gw_node, rcu);
  68         }
  69 }
  70
  71 static struct batadv_gw_node *
  72 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
  73 {
  74         struct batadv_gw_node *gw_node;
  75
  76         rcu_read_lock();
  77         gw_node = rcu_dereference(bat_priv->gw.curr_gw);
  78         if (!gw_node)
  79                 goto out;
  80
  81         if (!atomic_inc_not_zero(&gw_node->refcount))
  82                 gw_node = NULL;
  83
  84 out:
  85         rcu_read_unlock();
  86         return gw_node;
  87 }
  88
  89 struct batadv_orig_node *
  90 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
  91 {
  92         struct batadv_gw_node *gw_node;
  93         struct batadv_orig_node *orig_node = NULL;
  94
  95         gw_node = batadv_gw_get_selected_gw_node(bat_priv);
  96         if (!gw_node)
  97                 goto out;
  98
  99         rcu_read_lock();
 100         orig_node = gw_node->orig_node;
 101         if (!orig_node)
 102                 goto unlock;
 103
 104         if (!atomic_inc_not_zero(&orig_node->refcount))
 105                 orig_node = NULL;
 106
 107 unlock:
 108         rcu_read_unlock();
 109 out:
 110         if (gw_node)
 111                 batadv_gw_node_free_ref(gw_node);
 112         return orig_node;
 113 }
 114
 115 static void batadv_gw_select(struct batadv_priv *bat_priv,
 116                              struct batadv_gw_node *new_gw_node)
 117 {
 118         struct batadv_gw_node *curr_gw_node;
 119
 120         spin_lock_bh(&bat_priv->gw.list_lock);
 121
 122         if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
 123                 new_gw_node = NULL;
 124
 125         curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1);
 126         rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node);
 127
 128         if (curr_gw_node)
 129                 batadv_gw_node_free_ref(curr_gw_node);
 130
 131         spin_unlock_bh(&bat_priv->gw.list_lock);
 132 }
 133
 134 /**
 135  * batadv_gw_reselect - force a gateway reselection
 136  * @bat_priv: the bat priv with all the soft interface information
 137  *
 138  * Set a flag to remind the GW component to perform a new gateway reselection.
 139  * However this function does not ensure that the current gateway is going to be
 140  * deselected. The reselection mechanism may elect the same gateway once again.
 141  *
 142  * This means that invoking batadv_gw_reselect() does not guarantee a gateway
 143  * change and therefore a uevent is not necessarily expected.
 144  */
 145 void batadv_gw_reselect(struct batadv_priv *bat_priv)
 146 {
 147         atomic_set(&bat_priv->gw.reselect, 1);
 148 }
 149
 150 static struct batadv_gw_node *
 151 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
 152 {
 153         struct batadv_neigh_node *router;
 154         struct batadv_neigh_ifinfo *router_ifinfo;
 155         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 156         u64 max_gw_factor = 0;
 157         u64 tmp_gw_factor = 0;
 158         u8 max_tq = 0;
 159         u8 tq_avg;
 160         struct batadv_orig_node *orig_node;
 161
 162         rcu_read_lock();
 163         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 164                 orig_node = gw_node->orig_node;
 165                 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 166                 if (!router)
 167                         continue;
 168
 169                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 170                                                         BATADV_IF_DEFAULT);
 171                 if (!router_ifinfo)
 172                         goto next;
 173
 174                 if (!atomic_inc_not_zero(&gw_node->refcount))
 175                         goto next;
 176
 177                 tq_avg = router_ifinfo->bat_iv.tq_avg;
 178
 179                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 180                 case 1: /* fast connection */
 181                         tmp_gw_factor = tq_avg * tq_avg;
 182                         tmp_gw_factor *= gw_node->bandwidth_down;
 183                         tmp_gw_factor *= 100 * 100;
 184                         tmp_gw_factor >>= 18;
 185
 186                         if ((tmp_gw_factor > max_gw_factor) ||
 187                             ((tmp_gw_factor == max_gw_factor) &&
 188                              (tq_avg > max_tq))) {
 189                                 if (curr_gw)
 190                                         batadv_gw_node_free_ref(curr_gw);
 191                                 curr_gw = gw_node;
 192                                 atomic_inc(&curr_gw->refcount);
 193                         }
 194                         break;
 195
 196                 default: /* 2:  stable connection (use best statistic)
 197                           * 3:  fast-switch (use best statistic but change as
 198                           *     soon as a better gateway appears)
 199                           * XX: late-switch (use best statistic but change as
 200                           *     soon as a better gateway appears which has
 201                           *     $routing_class more tq points)
 202                           */
 203                         if (tq_avg > max_tq) {
 204                                 if (curr_gw)
 205                                         batadv_gw_node_free_ref(curr_gw);
 206                                 curr_gw = gw_node;
 207                                 atomic_inc(&curr_gw->refcount);
 208                         }
 209                         break;
 210                 }
 211
 212                 if (tq_avg > max_tq)
 213                         max_tq = tq_avg;
 214
 215                 if (tmp_gw_factor > max_gw_factor)
 216                         max_gw_factor = tmp_gw_factor;
 217
 218                 batadv_gw_node_free_ref(gw_node);
 219
 220 next:
 221                 batadv_neigh_node_free_ref(router);
 222                 if (router_ifinfo)
 223                         batadv_neigh_ifinfo_free_ref(router_ifinfo);
 224         }
 225         rcu_read_unlock();
 226
 227         return curr_gw;
 228 }
 229
 230 /**
 231  * batadv_gw_check_client_stop - check if client mode has been switched off
 232  * @bat_priv: the bat priv with all the soft interface information
 233  *
 234  * This function assumes the caller has checked that the gw state *is actually
 235  * changing*. This function is not supposed to be called when there is no state
 236  * change.
 237  */
 238 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
 239 {
 240         struct batadv_gw_node *curr_gw;
 241
 242         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 243                 return;
 244
 245         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 246         if (!curr_gw)
 247                 return;
 248
 249         /* deselect the current gateway so that next time that client mode is
 250          * enabled a proper GW_ADD event can be sent
 251          */
 252         batadv_gw_select(bat_priv, NULL);
 253
 254         /* if batman-adv is switching the gw client mode off and a gateway was
 255          * already selected, send a DEL uevent
 256          */
 257         batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
 258
 259         batadv_gw_node_free_ref(curr_gw);
 260 }
 261
 262 void batadv_gw_election(struct batadv_priv *bat_priv)
 263 {
 264         struct batadv_gw_node *curr_gw = NULL;
 265         struct batadv_gw_node *next_gw = NULL;
 266         struct batadv_neigh_node *router = NULL;
 267         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 268         char gw_addr[18] = { '\0' };
 269
 270         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 271                 goto out;
 272
 273         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 274
 275         if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
 276                 goto out;
 277
 278         next_gw = batadv_gw_get_best_gw_node(bat_priv);
 279
 280         if (curr_gw == next_gw)
 281                 goto out;
 282
 283         if (next_gw) {
 284                 sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
 285
 286                 router = batadv_orig_router_get(next_gw->orig_node,
 287                                                 BATADV_IF_DEFAULT);
 288                 if (!router) {
 289                         batadv_gw_reselect(bat_priv);
 290                         goto out;
 291                 }
 292
 293                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 294                                                         BATADV_IF_DEFAULT);
 295                 if (!router_ifinfo) {
 296                         batadv_gw_reselect(bat_priv);
 297                         goto out;
 298                 }
 299         }
 300
 301         if ((curr_gw) && (!next_gw)) {
 302                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 303                            "Removing selected gateway - no gateway in range\n");
 304                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
 305                                     NULL);
 306         } else if ((!curr_gw) && (next_gw)) {
 307                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 308                            "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 309                            next_gw->orig_node->orig,
 310                            next_gw->bandwidth_down / 10,
 311                            next_gw->bandwidth_down % 10,
 312                            next_gw->bandwidth_up / 10,
 313                            next_gw->bandwidth_up % 10,
 314                            router_ifinfo->bat_iv.tq_avg);
 315                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
 316                                     gw_addr);
 317         } else {
 318                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 319                            "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 320                            next_gw->orig_node->orig,
 321                            next_gw->bandwidth_down / 10,
 322                            next_gw->bandwidth_down % 10,
 323                            next_gw->bandwidth_up / 10,
 324                            next_gw->bandwidth_up % 10,
 325                            router_ifinfo->bat_iv.tq_avg);
 326                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
 327                                     gw_addr);
 328         }
 329
 330         batadv_gw_select(bat_priv, next_gw);
 331
 332 out:
 333         if (curr_gw)
 334                 batadv_gw_node_free_ref(curr_gw);
 335         if (next_gw)
 336                 batadv_gw_node_free_ref(next_gw);
 337         if (router)
 338                 batadv_neigh_node_free_ref(router);
 339         if (router_ifinfo)
 340                 batadv_neigh_ifinfo_free_ref(router_ifinfo);
 341 }
 342
 343 void batadv_gw_check_election(struct batadv_priv *bat_priv,
 344                               struct batadv_orig_node *orig_node)
 345 {
 346         struct batadv_neigh_ifinfo *router_orig_tq = NULL;
 347         struct batadv_neigh_ifinfo *router_gw_tq = NULL;
 348         struct batadv_orig_node *curr_gw_orig;
 349         struct batadv_neigh_node *router_gw = NULL;
 350         struct batadv_neigh_node *router_orig = NULL;
 351         u8 gw_tq_avg, orig_tq_avg;
 352
 353         curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 354         if (!curr_gw_orig)
 355                 goto reselect;
 356
 357         router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
 358         if (!router_gw)
 359                 goto reselect;
 360
 361         router_gw_tq = batadv_neigh_ifinfo_get(router_gw,
 362                                                BATADV_IF_DEFAULT);
 363         if (!router_gw_tq)
 364                 goto reselect;
 365
 366         /* this node already is the gateway */
 367         if (curr_gw_orig == orig_node)
 368                 goto out;
 369
 370         router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 371         if (!router_orig)
 372                 goto out;
 373
 374         router_orig_tq = batadv_neigh_ifinfo_get(router_orig,
 375                                                  BATADV_IF_DEFAULT);
 376         if (!router_orig_tq)
 377                 goto out;
 378
 379         gw_tq_avg = router_gw_tq->bat_iv.tq_avg;
 380         orig_tq_avg = router_orig_tq->bat_iv.tq_avg;
 381
 382         /* the TQ value has to be better */
 383         if (orig_tq_avg < gw_tq_avg)
 384                 goto out;
 385
 386         /* if the routing class is greater than 3 the value tells us how much
 387          * greater the TQ value of the new gateway must be
 388          */
 389         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 390             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 391                 goto out;
 392
 393         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 394                    "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
 395                    gw_tq_avg, orig_tq_avg);
 396
 397 reselect:
 398         batadv_gw_reselect(bat_priv);
 399 out:
 400         if (curr_gw_orig)
 401                 batadv_orig_node_free_ref(curr_gw_orig);
 402         if (router_gw)
 403                 batadv_neigh_node_free_ref(router_gw);
 404         if (router_orig)
 405                 batadv_neigh_node_free_ref(router_orig);
 406         if (router_gw_tq)
 407                 batadv_neigh_ifinfo_free_ref(router_gw_tq);
 408         if (router_orig_tq)
 409                 batadv_neigh_ifinfo_free_ref(router_orig_tq);
 410 }
 411
 412 /**
 413  * batadv_gw_node_add - add gateway node to list of available gateways
 414  * @bat_priv: the bat priv with all the soft interface information
 415  * @orig_node: originator announcing gateway capabilities
 416  * @gateway: announced bandwidth information
 417  */
 418 static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 419                                struct batadv_orig_node *orig_node,
 420                                struct batadv_tvlv_gateway_data *gateway)
 421 {
 422         struct batadv_gw_node *gw_node;
 423
 424         if (gateway->bandwidth_down == 0)
 425                 return;
 426
 427         if (!atomic_inc_not_zero(&orig_node->refcount))
 428                 return;
 429
 430         gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 431         if (!gw_node) {
 432                 batadv_orig_node_free_ref(orig_node);
 433                 return;
 434         }
 435
 436         INIT_HLIST_NODE(&gw_node->list);
 437         gw_node->orig_node = orig_node;
 438         gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 439         gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 440         atomic_set(&gw_node->refcount, 1);
 441
 442         spin_lock_bh(&bat_priv->gw.list_lock);
 443         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list);
 444         spin_unlock_bh(&bat_priv->gw.list_lock);
 445
 446         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 447                    "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
 448                    orig_node->orig,
 449                    ntohl(gateway->bandwidth_down) / 10,
 450                    ntohl(gateway->bandwidth_down) % 10,
 451                    ntohl(gateway->bandwidth_up) / 10,
 452                    ntohl(gateway->bandwidth_up) % 10);
 453 }
 454
 455 /**
 456  * batadv_gw_node_get - retrieve gateway node from list of available gateways
 457  * @bat_priv: the bat priv with all the soft interface information
 458  * @orig_node: originator announcing gateway capabilities
 459  *
 460  * Returns gateway node if found or NULL otherwise.
 461  */
 462 static struct batadv_gw_node *
 463 batadv_gw_node_get(struct batadv_priv *bat_priv,
 464                    struct batadv_orig_node *orig_node)
 465 {
 466         struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
 467
 468         rcu_read_lock();
 469         hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) {
 470                 if (gw_node_tmp->orig_node != orig_node)
 471                         continue;
 472
 473                 if (!atomic_inc_not_zero(&gw_node_tmp->refcount))
 474                         continue;
 475
 476                 gw_node = gw_node_tmp;
 477                 break;
 478         }
 479         rcu_read_unlock();
 480
 481         return gw_node;
 482 }
 483
 484 /**
 485  * batadv_gw_node_update - update list of available gateways with changed
 486  *  bandwidth information
 487  * @bat_priv: the bat priv with all the soft interface information
 488  * @orig_node: originator announcing gateway capabilities
 489  * @gateway: announced bandwidth information
 490  */
 491 void batadv_gw_node_update(struct batadv_priv *bat_priv,
 492                            struct batadv_orig_node *orig_node,
 493                            struct batadv_tvlv_gateway_data *gateway)
 494 {
 495         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 496
 497         gw_node = batadv_gw_node_get(bat_priv, orig_node);
 498         if (!gw_node) {
 499                 batadv_gw_node_add(bat_priv, orig_node, gateway);
 500                 goto out;
 501         }
 502
 503         if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) &&
 504             (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up)))
 505                 goto out;
 506
 507         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 508                    "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
 509                    orig_node->orig,
 510                    gw_node->bandwidth_down / 10,
 511                    gw_node->bandwidth_down % 10,
 512                    gw_node->bandwidth_up / 10,
 513                    gw_node->bandwidth_up % 10,
 514                    ntohl(gateway->bandwidth_down) / 10,
 515                    ntohl(gateway->bandwidth_down) % 10,
 516                    ntohl(gateway->bandwidth_up) / 10,
 517                    ntohl(gateway->bandwidth_up) % 10);
 518
 519         gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 520         gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 521
 522         if (ntohl(gateway->bandwidth_down) == 0) {
 523                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 524                            "Gateway %pM removed from gateway list\n",
 525                            orig_node->orig);
 526
 527                 /* Note: We don't need a NULL check here, since curr_gw never
 528                  * gets dereferenced.
 529                  */
 530                 spin_lock_bh(&bat_priv->gw.list_lock);
 531                 hlist_del_init_rcu(&gw_node->list);
 532                 spin_unlock_bh(&bat_priv->gw.list_lock);
 533
 534                 batadv_gw_node_free_ref(gw_node);
 535
 536                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 537                 if (gw_node == curr_gw)
 538                         batadv_gw_reselect(bat_priv);
 539
 540                 if (curr_gw)
 541                         batadv_gw_node_free_ref(curr_gw);
 542         }
 543
 544 out:
 545         if (gw_node)
 546                 batadv_gw_node_free_ref(gw_node);
 547 }
 548
 549 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 550                            struct batadv_orig_node *orig_node)
 551 {
 552         struct batadv_tvlv_gateway_data gateway;
 553
 554         gateway.bandwidth_down = 0;
 555         gateway.bandwidth_up = 0;
 556
 557         batadv_gw_node_update(bat_priv, orig_node, &gateway);
 558 }
 559
 560 void batadv_gw_node_free(struct batadv_priv *bat_priv)
 561 {
 562         struct batadv_gw_node *gw_node;
 563         struct hlist_node *node_tmp;
 564
 565         spin_lock_bh(&bat_priv->gw.list_lock);
 566         hlist_for_each_entry_safe(gw_node, node_tmp,
 567                                   &bat_priv->gw.list, list) {
 568
 569                 hlist_del_init_rcu(&gw_node->list);
 570                 batadv_gw_node_free_ref(gw_node);
 571         }
 572         spin_unlock_bh(&bat_priv->gw.list_lock);
 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                 /* fails if orig_node has no router */
 637                 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
 638                         continue;
 639
 640                 gw_count++;
 641         }
 642         rcu_read_unlock();
 643
 644         if (gw_count == 0)
 645                 seq_puts(seq, "No gateways in range ...\n");
 646
 647 out:
 648         if (primary_if)
 649                 batadv_hardif_free_ref(primary_if);
 650         return 0;
 651 }
 652
 653 /**
 654  * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message
 655  * @skb: the packet to check
 656  * @header_len: a pointer to the batman-adv header size
 657  * @chaddr: buffer where the client address will be stored. Valid
 658  *  only if the function returns BATADV_DHCP_TO_CLIENT
 659  *
 660  * Returns:
 661  * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
 662  *   while parsing it
 663  * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
 664  * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
 665  *
 666  * This function may re-allocate the data buffer of the skb passed as argument.
 667  */
 668 enum batadv_dhcp_recipient
 669 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
 670                              u8 *chaddr)
 671 {
 672         enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
 673         struct ethhdr *ethhdr;
 674         struct iphdr *iphdr;
 675         struct ipv6hdr *ipv6hdr;
 676         struct udphdr *udphdr;
 677         struct vlan_ethhdr *vhdr;
 678         int chaddr_offset;
 679         __be16 proto;
 680         u8 *p;
 681
 682         /* check for ethernet header */
 683         if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
 684                 return BATADV_DHCP_NO;
 685
 686         ethhdr = eth_hdr(skb);
 687         proto = ethhdr->h_proto;
 688         *header_len += ETH_HLEN;
 689
 690         /* check for initial vlan header */
 691         if (proto == htons(ETH_P_8021Q)) {
 692                 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
 693                         return BATADV_DHCP_NO;
 694
 695                 vhdr = vlan_eth_hdr(skb);
 696                 proto = vhdr->h_vlan_encapsulated_proto;
 697                 *header_len += VLAN_HLEN;
 698         }
 699
 700         /* check for ip header */
 701         switch (proto) {
 702         case htons(ETH_P_IP):
 703                 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
 704                         return BATADV_DHCP_NO;
 705
 706                 iphdr = (struct iphdr *)(skb->data + *header_len);
 707                 *header_len += iphdr->ihl * 4;
 708
 709                 /* check for udp header */
 710                 if (iphdr->protocol != IPPROTO_UDP)
 711                         return BATADV_DHCP_NO;
 712
 713                 break;
 714         case htons(ETH_P_IPV6):
 715                 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
 716                         return BATADV_DHCP_NO;
 717
 718                 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
 719                 *header_len += sizeof(*ipv6hdr);
 720
 721                 /* check for udp header */
 722                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 723                         return BATADV_DHCP_NO;
 724
 725                 break;
 726         default:
 727                 return BATADV_DHCP_NO;
 728         }
 729
 730         if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
 731                 return BATADV_DHCP_NO;
 732
 733         udphdr = (struct udphdr *)(skb->data + *header_len);
 734         *header_len += sizeof(*udphdr);
 735
 736         /* check for bootp port */
 737         switch (proto) {
 738         case htons(ETH_P_IP):
 739                 if (udphdr->dest == htons(67))
 740                         ret = BATADV_DHCP_TO_SERVER;
 741                 else if (udphdr->source == htons(67))
 742                         ret = BATADV_DHCP_TO_CLIENT;
 743                 break;
 744         case htons(ETH_P_IPV6):
 745                 if (udphdr->dest == htons(547))
 746                         ret = BATADV_DHCP_TO_SERVER;
 747                 else if (udphdr->source == htons(547))
 748                         ret = BATADV_DHCP_TO_CLIENT;
 749                 break;
 750         }
 751
 752         chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
 753         /* store the client address if the message is going to a client */
 754         if (ret == BATADV_DHCP_TO_CLIENT &&
 755             pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) {
 756                 /* check if the DHCP packet carries an Ethernet DHCP */
 757                 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
 758                 if (*p != BATADV_DHCP_HTYPE_ETHERNET)
 759                         return BATADV_DHCP_NO;
 760
 761                 /* check if the DHCP packet carries a valid Ethernet address */
 762                 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
 763                 if (*p != ETH_ALEN)
 764                         return BATADV_DHCP_NO;
 765
 766                 ether_addr_copy(chaddr, skb->data + chaddr_offset);
 767         }
 768
 769         return ret;
 770 }
 771
 772 /**
 773  * batadv_gw_out_of_range - check if the dhcp request destination is the best gw
 774  * @bat_priv: the bat priv with all the soft interface information
 775  * @skb: the outgoing packet
 776  *
 777  * Check if the skb is a DHCP request and if it is sent to the current best GW
 778  * server. Due to topology changes it may be the case that the GW server
 779  * previously selected is not the best one anymore.
 780  *
 781  * Returns true if the packet destination is unicast and it is not the best gw,
 782  * false otherwise.
 783  *
 784  * This call might reallocate skb data.
 785  * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
 786  */
 787 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 788                             struct sk_buff *skb)
 789 {
 790         struct batadv_neigh_node *neigh_curr = NULL;
 791         struct batadv_neigh_node *neigh_old = NULL;
 792         struct batadv_orig_node *orig_dst_node = NULL;
 793         struct batadv_gw_node *gw_node = NULL;
 794         struct batadv_gw_node *curr_gw = NULL;
 795         struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
 796         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 797         bool out_of_range = false;
 798         u8 curr_tq_avg;
 799         unsigned short vid;
 800
 801         vid = batadv_get_vid(skb, 0);
 802
 803         orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
 804                                                  ethhdr->h_dest, vid);
 805         if (!orig_dst_node)
 806                 goto out;
 807
 808         gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
 809         if (!gw_node)
 810                 goto out;
 811
 812         switch (atomic_read(&bat_priv->gw_mode)) {
 813         case BATADV_GW_MODE_SERVER:
 814                 /* If we are a GW then we are our best GW. We can artificially
 815                  * set the tq towards ourself as the maximum value
 816                  */
 817                 curr_tq_avg = BATADV_TQ_MAX_VALUE;
 818                 break;
 819         case BATADV_GW_MODE_CLIENT:
 820                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 821                 if (!curr_gw)
 822                         goto out;
 823
 824                 /* packet is going to our gateway */
 825                 if (curr_gw->orig_node == orig_dst_node)
 826                         goto out;
 827
 828                 /* If the dhcp packet has been sent to a different gw,
 829                  * we have to evaluate whether the old gw is still
 830                  * reliable enough
 831                  */
 832                 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
 833                                                 NULL);
 834                 if (!neigh_curr)
 835                         goto out;
 836
 837                 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
 838                                                       BATADV_IF_DEFAULT);
 839                 if (!curr_ifinfo)
 840                         goto out;
 841
 842                 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
 843                 batadv_neigh_ifinfo_free_ref(curr_ifinfo);
 844
 845                 break;
 846         case BATADV_GW_MODE_OFF:
 847         default:
 848                 goto out;
 849         }
 850
 851         neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
 852         if (!neigh_old)
 853                 goto out;
 854
 855         old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
 856         if (!old_ifinfo)
 857                 goto out;
 858
 859         if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
 860                 out_of_range = true;
 861         batadv_neigh_ifinfo_free_ref(old_ifinfo);
 862
 863 out:
 864         if (orig_dst_node)
 865                 batadv_orig_node_free_ref(orig_dst_node);
 866         if (curr_gw)
 867                 batadv_gw_node_free_ref(curr_gw);
 868         if (gw_node)
 869                 batadv_gw_node_free_ref(gw_node);
 870         if (neigh_old)
 871                 batadv_neigh_node_free_ref(neigh_old);
 872         if (neigh_curr)
 873                 batadv_neigh_node_free_ref(neigh_curr);
 874         return out_of_range;
 875 }