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         uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 157         uint32_t gw_divisor;
 158         uint8_t max_tq = 0;
 159         uint8_t tq_avg;
 160         struct batadv_orig_node *orig_node;
 161
 162         gw_divisor = BATADV_TQ_LOCAL_WINDOW_SIZE * BATADV_TQ_LOCAL_WINDOW_SIZE;
 163         gw_divisor *= 64;
 164
 165         rcu_read_lock();
 166         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 167                 if (gw_node->deleted)
 168                         continue;
 169
 170                 orig_node = gw_node->orig_node;
 171                 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 172                 if (!router)
 173                         continue;
 174
 175                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 176                                                         BATADV_IF_DEFAULT);
 177                 if (!router_ifinfo)
 178                         goto next;
 179
 180                 if (!atomic_inc_not_zero(&gw_node->refcount))
 181                         goto next;
 182
 183                 tq_avg = router_ifinfo->bat_iv.tq_avg;
 184
 185                 switch (atomic_read(&bat_priv->gw_sel_class)) {
 186                 case 1: /* fast connection */
 187                         tmp_gw_factor = tq_avg * tq_avg;
 188                         tmp_gw_factor *= gw_node->bandwidth_down;
 189                         tmp_gw_factor *= 100 * 100;
 190                         tmp_gw_factor /= gw_divisor;
 191
 192                         if ((tmp_gw_factor > max_gw_factor) ||
 193                             ((tmp_gw_factor == max_gw_factor) &&
 194                              (tq_avg > max_tq))) {
 195                                 if (curr_gw)
 196                                         batadv_gw_node_free_ref(curr_gw);
 197                                 curr_gw = gw_node;
 198                                 atomic_inc(&curr_gw->refcount);
 199                         }
 200                         break;
 201
 202                 default: /* 2:  stable connection (use best statistic)
 203                           * 3:  fast-switch (use best statistic but change as
 204                           *     soon as a better gateway appears)
 205                           * XX: late-switch (use best statistic but change as
 206                           *     soon as a better gateway appears which has
 207                           *     $routing_class more tq points)
 208                           */
 209                         if (tq_avg > max_tq) {
 210                                 if (curr_gw)
 211                                         batadv_gw_node_free_ref(curr_gw);
 212                                 curr_gw = gw_node;
 213                                 atomic_inc(&curr_gw->refcount);
 214                         }
 215                         break;
 216                 }
 217
 218                 if (tq_avg > max_tq)
 219                         max_tq = tq_avg;
 220
 221                 if (tmp_gw_factor > max_gw_factor)
 222                         max_gw_factor = tmp_gw_factor;
 223
 224                 batadv_gw_node_free_ref(gw_node);
 225
 226 next:
 227                 batadv_neigh_node_free_ref(router);
 228                 if (router_ifinfo)
 229                         batadv_neigh_ifinfo_free_ref(router_ifinfo);
 230         }
 231         rcu_read_unlock();
 232
 233         return curr_gw;
 234 }
 235
 236 /**
 237  * batadv_gw_check_client_stop - check if client mode has been switched off
 238  * @bat_priv: the bat priv with all the soft interface information
 239  *
 240  * This function assumes the caller has checked that the gw state *is actually
 241  * changing*. This function is not supposed to be called when there is no state
 242  * change.
 243  */
 244 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
 245 {
 246         struct batadv_gw_node *curr_gw;
 247
 248         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 249                 return;
 250
 251         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 252         if (!curr_gw)
 253                 return;
 254
 255         /* deselect the current gateway so that next time that client mode is
 256          * enabled a proper GW_ADD event can be sent
 257          */
 258         batadv_gw_select(bat_priv, NULL);
 259
 260         /* if batman-adv is switching the gw client mode off and a gateway was
 261          * already selected, send a DEL uevent
 262          */
 263         batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
 264
 265         batadv_gw_node_free_ref(curr_gw);
 266 }
 267
 268 void batadv_gw_election(struct batadv_priv *bat_priv)
 269 {
 270         struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL;
 271         struct batadv_neigh_node *router = NULL;
 272         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 273         char gw_addr[18] = { '\0' };
 274
 275         if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
 276                 goto out;
 277
 278         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 279
 280         if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
 281                 goto out;
 282
 283         next_gw = batadv_gw_get_best_gw_node(bat_priv);
 284
 285         if (curr_gw == next_gw)
 286                 goto out;
 287
 288         if (next_gw) {
 289                 sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
 290
 291                 router = batadv_orig_router_get(next_gw->orig_node,
 292                                                 BATADV_IF_DEFAULT);
 293                 if (!router) {
 294                         batadv_gw_reselect(bat_priv);
 295                         goto out;
 296                 }
 297
 298                 router_ifinfo = batadv_neigh_ifinfo_get(router,
 299                                                         BATADV_IF_DEFAULT);
 300                 if (!router_ifinfo) {
 301                         batadv_gw_reselect(bat_priv);
 302                         goto out;
 303                 }
 304         }
 305
 306         if ((curr_gw) && (!next_gw)) {
 307                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 308                            "Removing selected gateway - no gateway in range\n");
 309                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
 310                                     NULL);
 311         } else if ((!curr_gw) && (next_gw)) {
 312                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 313                            "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 314                            next_gw->orig_node->orig,
 315                            next_gw->bandwidth_down / 10,
 316                            next_gw->bandwidth_down % 10,
 317                            next_gw->bandwidth_up / 10,
 318                            next_gw->bandwidth_up % 10,
 319                            router_ifinfo->bat_iv.tq_avg);
 320                 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
 321                                     gw_addr);
 322         } else {
 323                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 324                            "Changing 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_CHANGE,
 332                                     gw_addr);
 333         }
 334
 335         batadv_gw_select(bat_priv, next_gw);
 336
 337 out:
 338         if (curr_gw)
 339                 batadv_gw_node_free_ref(curr_gw);
 340         if (next_gw)
 341                 batadv_gw_node_free_ref(next_gw);
 342         if (router)
 343                 batadv_neigh_node_free_ref(router);
 344         if (router_ifinfo)
 345                 batadv_neigh_ifinfo_free_ref(router_ifinfo);
 346 }
 347
 348 void batadv_gw_check_election(struct batadv_priv *bat_priv,
 349                               struct batadv_orig_node *orig_node)
 350 {
 351         struct batadv_neigh_ifinfo *router_orig_tq = NULL;
 352         struct batadv_neigh_ifinfo *router_gw_tq = NULL;
 353         struct batadv_orig_node *curr_gw_orig;
 354         struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL;
 355         uint8_t gw_tq_avg, orig_tq_avg;
 356
 357         curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 358         if (!curr_gw_orig)
 359                 goto reselect;
 360
 361         router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
 362         if (!router_gw)
 363                 goto reselect;
 364
 365         router_gw_tq = batadv_neigh_ifinfo_get(router_gw,
 366                                                BATADV_IF_DEFAULT);
 367         if (!router_gw_tq)
 368                 goto reselect;
 369
 370         /* this node already is the gateway */
 371         if (curr_gw_orig == orig_node)
 372                 goto out;
 373
 374         router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
 375         if (!router_orig)
 376                 goto out;
 377
 378         router_orig_tq = batadv_neigh_ifinfo_get(router_orig,
 379                                                  BATADV_IF_DEFAULT);
 380         if (!router_orig_tq)
 381                 goto out;
 382
 383         gw_tq_avg = router_gw_tq->bat_iv.tq_avg;
 384         orig_tq_avg = router_orig_tq->bat_iv.tq_avg;
 385
 386         /* the TQ value has to be better */
 387         if (orig_tq_avg < gw_tq_avg)
 388                 goto out;
 389
 390         /* if the routing class is greater than 3 the value tells us how much
 391          * greater the TQ value of the new gateway must be
 392          */
 393         if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 394             (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 395                 goto out;
 396
 397         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 398                    "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
 399                    gw_tq_avg, orig_tq_avg);
 400
 401 reselect:
 402         batadv_gw_reselect(bat_priv);
 403 out:
 404         if (curr_gw_orig)
 405                 batadv_orig_node_free_ref(curr_gw_orig);
 406         if (router_gw)
 407                 batadv_neigh_node_free_ref(router_gw);
 408         if (router_orig)
 409                 batadv_neigh_node_free_ref(router_orig);
 410         if (router_gw_tq)
 411                 batadv_neigh_ifinfo_free_ref(router_gw_tq);
 412         if (router_orig_tq)
 413                 batadv_neigh_ifinfo_free_ref(router_orig_tq);
 414 }
 415
 416 /**
 417  * batadv_gw_node_add - add gateway node to list of available gateways
 418  * @bat_priv: the bat priv with all the soft interface information
 419  * @orig_node: originator announcing gateway capabilities
 420  * @gateway: announced bandwidth information
 421  */
 422 static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 423                                struct batadv_orig_node *orig_node,
 424                                struct batadv_tvlv_gateway_data *gateway)
 425 {
 426         struct batadv_gw_node *gw_node;
 427
 428         if (gateway->bandwidth_down == 0)
 429                 return;
 430
 431         if (!atomic_inc_not_zero(&orig_node->refcount))
 432                 return;
 433
 434         gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 435         if (!gw_node) {
 436                 batadv_orig_node_free_ref(orig_node);
 437                 return;
 438         }
 439
 440         INIT_HLIST_NODE(&gw_node->list);
 441         gw_node->orig_node = orig_node;
 442         gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 443         gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 444         atomic_set(&gw_node->refcount, 1);
 445
 446         spin_lock_bh(&bat_priv->gw.list_lock);
 447         hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list);
 448         spin_unlock_bh(&bat_priv->gw.list_lock);
 449
 450         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 451                    "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
 452                    orig_node->orig,
 453                    ntohl(gateway->bandwidth_down) / 10,
 454                    ntohl(gateway->bandwidth_down) % 10,
 455                    ntohl(gateway->bandwidth_up) / 10,
 456                    ntohl(gateway->bandwidth_up) % 10);
 457 }
 458
 459 /**
 460  * batadv_gw_node_get - retrieve gateway node from list of available gateways
 461  * @bat_priv: the bat priv with all the soft interface information
 462  * @orig_node: originator announcing gateway capabilities
 463  *
 464  * Returns gateway node if found or NULL otherwise.
 465  */
 466 static struct batadv_gw_node *
 467 batadv_gw_node_get(struct batadv_priv *bat_priv,
 468                    struct batadv_orig_node *orig_node)
 469 {
 470         struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
 471
 472         rcu_read_lock();
 473         hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) {
 474                 if (gw_node_tmp->orig_node != orig_node)
 475                         continue;
 476
 477                 if (gw_node_tmp->deleted)
 478                         continue;
 479
 480                 if (!atomic_inc_not_zero(&gw_node_tmp->refcount))
 481                         continue;
 482
 483                 gw_node = gw_node_tmp;
 484                 break;
 485         }
 486         rcu_read_unlock();
 487
 488         return gw_node;
 489 }
 490
 491 /**
 492  * batadv_gw_node_update - update list of available gateways with changed
 493  *  bandwidth information
 494  * @bat_priv: the bat priv with all the soft interface information
 495  * @orig_node: originator announcing gateway capabilities
 496  * @gateway: announced bandwidth information
 497  */
 498 void batadv_gw_node_update(struct batadv_priv *bat_priv,
 499                            struct batadv_orig_node *orig_node,
 500                            struct batadv_tvlv_gateway_data *gateway)
 501 {
 502         struct batadv_gw_node *gw_node, *curr_gw = NULL;
 503
 504         gw_node = batadv_gw_node_get(bat_priv, orig_node);
 505         if (!gw_node) {
 506                 batadv_gw_node_add(bat_priv, orig_node, gateway);
 507                 goto out;
 508         }
 509
 510         if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) &&
 511             (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up)))
 512                 goto out;
 513
 514         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 515                    "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
 516                    orig_node->orig,
 517                    gw_node->bandwidth_down / 10,
 518                    gw_node->bandwidth_down % 10,
 519                    gw_node->bandwidth_up / 10,
 520                    gw_node->bandwidth_up % 10,
 521                    ntohl(gateway->bandwidth_down) / 10,
 522                    ntohl(gateway->bandwidth_down) % 10,
 523                    ntohl(gateway->bandwidth_up) / 10,
 524                    ntohl(gateway->bandwidth_up) % 10);
 525
 526         gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 527         gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 528
 529         gw_node->deleted = 0;
 530         if (ntohl(gateway->bandwidth_down) == 0) {
 531                 gw_node->deleted = jiffies;
 532                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 533                            "Gateway %pM removed from gateway list\n",
 534                            orig_node->orig);
 535
 536                 /* Note: We don't need a NULL check here, since curr_gw never
 537                  * gets dereferenced.
 538                  */
 539                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 540                 if (gw_node == curr_gw)
 541                         batadv_gw_reselect(bat_priv);
 542         }
 543
 544 out:
 545         if (curr_gw)
 546                 batadv_gw_node_free_ref(curr_gw);
 547         if (gw_node)
 548                 batadv_gw_node_free_ref(gw_node);
 549 }
 550
 551 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 552                            struct batadv_orig_node *orig_node)
 553 {
 554         struct batadv_tvlv_gateway_data gateway;
 555
 556         gateway.bandwidth_down = 0;
 557         gateway.bandwidth_up = 0;
 558
 559         batadv_gw_node_update(bat_priv, orig_node, &gateway);
 560 }
 561
 562 void batadv_gw_node_purge(struct batadv_priv *bat_priv)
 563 {
 564         struct batadv_gw_node *gw_node, *curr_gw;
 565         struct hlist_node *node_tmp;
 566         unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT);
 567         int do_reselect = 0;
 568
 569         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 570
 571         spin_lock_bh(&bat_priv->gw.list_lock);
 572
 573         hlist_for_each_entry_safe(gw_node, node_tmp,
 574                                   &bat_priv->gw.list, list) {
 575                 if (((!gw_node->deleted) ||
 576                      (time_before(jiffies, gw_node->deleted + timeout))) &&
 577                     atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE)
 578                         continue;
 579
 580                 if (curr_gw == gw_node)
 581                         do_reselect = 1;
 582
 583                 hlist_del_rcu(&gw_node->list);
 584                 batadv_gw_node_free_ref(gw_node);
 585         }
 586
 587         spin_unlock_bh(&bat_priv->gw.list_lock);
 588
 589         /* gw_reselect() needs to acquire the gw_list_lock */
 590         if (do_reselect)
 591                 batadv_gw_reselect(bat_priv);
 592
 593         if (curr_gw)
 594                 batadv_gw_node_free_ref(curr_gw);
 595 }
 596
 597 /* fails if orig_node has no router */
 598 static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
 599                                     struct seq_file *seq,
 600                                     const struct batadv_gw_node *gw_node)
 601 {
 602         struct batadv_gw_node *curr_gw;
 603         struct batadv_neigh_node *router;
 604         struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 605         int ret = -1;
 606
 607         router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
 608         if (!router)
 609                 goto out;
 610
 611         router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
 612         if (!router_ifinfo)
 613                 goto out;
 614
 615         curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 616
 617         seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
 618                    (curr_gw == gw_node ? "=>" : "  "),
 619                    gw_node->orig_node->orig,
 620                    router_ifinfo->bat_iv.tq_avg, router->addr,
 621                    router->if_incoming->net_dev->name,
 622                    gw_node->bandwidth_down / 10,
 623                    gw_node->bandwidth_down % 10,
 624                    gw_node->bandwidth_up / 10,
 625                    gw_node->bandwidth_up % 10);
 626         ret = seq_has_overflowed(seq) ? -1 : 0;
 627
 628         if (curr_gw)
 629                 batadv_gw_node_free_ref(curr_gw);
 630 out:
 631         if (router_ifinfo)
 632                 batadv_neigh_ifinfo_free_ref(router_ifinfo);
 633         if (router)
 634                 batadv_neigh_node_free_ref(router);
 635         return ret;
 636 }
 637
 638 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 639 {
 640         struct net_device *net_dev = (struct net_device *)seq->private;
 641         struct batadv_priv *bat_priv = netdev_priv(net_dev);
 642         struct batadv_hard_iface *primary_if;
 643         struct batadv_gw_node *gw_node;
 644         int gw_count = 0;
 645
 646         primary_if = batadv_seq_print_text_primary_if_get(seq);
 647         if (!primary_if)
 648                 goto out;
 649
 650         seq_printf(seq,
 651                    "      %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
 652                    "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
 653                    BATADV_SOURCE_VERSION, primary_if->net_dev->name,
 654                    primary_if->net_dev->dev_addr, net_dev->name);
 655
 656         rcu_read_lock();
 657         hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
 658                 if (gw_node->deleted)
 659                         continue;
 660
 661                 /* fails if orig_node has no router */
 662                 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
 663                         continue;
 664
 665                 gw_count++;
 666         }
 667         rcu_read_unlock();
 668
 669         if (gw_count == 0)
 670                 seq_puts(seq, "No gateways in range ...\n");
 671
 672 out:
 673         if (primary_if)
 674                 batadv_hardif_free_ref(primary_if);
 675         return 0;
 676 }
 677
 678 /**
 679  * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message
 680  * @skb: the packet to check
 681  * @header_len: a pointer to the batman-adv header size
 682  * @chaddr: buffer where the client address will be stored. Valid
 683  *  only if the function returns BATADV_DHCP_TO_CLIENT
 684  *
 685  * Returns:
 686  * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
 687  *   while parsing it
 688  * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
 689  * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
 690  *
 691  * This function may re-allocate the data buffer of the skb passed as argument.
 692  */
 693 enum batadv_dhcp_recipient
 694 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
 695                              uint8_t *chaddr)
 696 {
 697         enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
 698         struct ethhdr *ethhdr;
 699         struct iphdr *iphdr;
 700         struct ipv6hdr *ipv6hdr;
 701         struct udphdr *udphdr;
 702         struct vlan_ethhdr *vhdr;
 703         int chaddr_offset;
 704         __be16 proto;
 705         uint8_t *p;
 706
 707         /* check for ethernet header */
 708         if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
 709                 return BATADV_DHCP_NO;
 710
 711         ethhdr = eth_hdr(skb);
 712         proto = ethhdr->h_proto;
 713         *header_len += ETH_HLEN;
 714
 715         /* check for initial vlan header */
 716         if (proto == htons(ETH_P_8021Q)) {
 717                 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
 718                         return BATADV_DHCP_NO;
 719
 720                 vhdr = vlan_eth_hdr(skb);
 721                 proto = vhdr->h_vlan_encapsulated_proto;
 722                 *header_len += VLAN_HLEN;
 723         }
 724
 725         /* check for ip header */
 726         switch (proto) {
 727         case htons(ETH_P_IP):
 728                 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
 729                         return BATADV_DHCP_NO;
 730
 731                 iphdr = (struct iphdr *)(skb->data + *header_len);
 732                 *header_len += iphdr->ihl * 4;
 733
 734                 /* check for udp header */
 735                 if (iphdr->protocol != IPPROTO_UDP)
 736                         return BATADV_DHCP_NO;
 737
 738                 break;
 739         case htons(ETH_P_IPV6):
 740                 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
 741                         return BATADV_DHCP_NO;
 742
 743                 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
 744                 *header_len += sizeof(*ipv6hdr);
 745
 746                 /* check for udp header */
 747                 if (ipv6hdr->nexthdr != IPPROTO_UDP)
 748                         return BATADV_DHCP_NO;
 749
 750                 break;
 751         default:
 752                 return BATADV_DHCP_NO;
 753         }
 754
 755         if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
 756                 return BATADV_DHCP_NO;
 757
 758         udphdr = (struct udphdr *)(skb->data + *header_len);
 759         *header_len += sizeof(*udphdr);
 760
 761         /* check for bootp port */
 762         switch (proto) {
 763         case htons(ETH_P_IP):
 764                 if (udphdr->dest == htons(67))
 765                         ret = BATADV_DHCP_TO_SERVER;
 766                 else if (udphdr->source == htons(67))
 767                         ret = BATADV_DHCP_TO_CLIENT;
 768                 break;
 769         case htons(ETH_P_IPV6):
 770                 if (udphdr->dest == htons(547))
 771                         ret = BATADV_DHCP_TO_SERVER;
 772                 else if (udphdr->source == htons(547))
 773                         ret = BATADV_DHCP_TO_CLIENT;
 774                 break;
 775         }
 776
 777         chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
 778         /* store the client address if the message is going to a client */
 779         if (ret == BATADV_DHCP_TO_CLIENT &&
 780             pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) {
 781                 /* check if the DHCP packet carries an Ethernet DHCP */
 782                 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
 783                 if (*p != BATADV_DHCP_HTYPE_ETHERNET)
 784                         return BATADV_DHCP_NO;
 785
 786                 /* check if the DHCP packet carries a valid Ethernet address */
 787                 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
 788                 if (*p != ETH_ALEN)
 789                         return BATADV_DHCP_NO;
 790
 791                 ether_addr_copy(chaddr, skb->data + chaddr_offset);
 792         }
 793
 794         return ret;
 795 }
 796
 797 /**
 798  * batadv_gw_out_of_range - check if the dhcp request destination is the best gw
 799  * @bat_priv: the bat priv with all the soft interface information
 800  * @skb: the outgoing packet
 801  *
 802  * Check if the skb is a DHCP request and if it is sent to the current best GW
 803  * server. Due to topology changes it may be the case that the GW server
 804  * previously selected is not the best one anymore.
 805  *
 806  * Returns true if the packet destination is unicast and it is not the best gw,
 807  * false otherwise.
 808  *
 809  * This call might reallocate skb data.
 810  * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
 811  */
 812 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 813                             struct sk_buff *skb)
 814 {
 815         struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL;
 816         struct batadv_orig_node *orig_dst_node = NULL;
 817         struct batadv_gw_node *gw_node = NULL, *curr_gw = NULL;
 818         struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
 819         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 820         bool out_of_range = false;
 821         uint8_t curr_tq_avg;
 822         unsigned short vid;
 823
 824         vid = batadv_get_vid(skb, 0);
 825
 826         orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
 827                                                  ethhdr->h_dest, vid);
 828         if (!orig_dst_node)
 829                 goto out;
 830
 831         gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
 832         if (!gw_node)
 833                 goto out;
 834
 835         switch (atomic_read(&bat_priv->gw_mode)) {
 836         case BATADV_GW_MODE_SERVER:
 837                 /* If we are a GW then we are our best GW. We can artificially
 838                  * set the tq towards ourself as the maximum value
 839                  */
 840                 curr_tq_avg = BATADV_TQ_MAX_VALUE;
 841                 break;
 842         case BATADV_GW_MODE_CLIENT:
 843                 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 844                 if (!curr_gw)
 845                         goto out;
 846
 847                 /* packet is going to our gateway */
 848                 if (curr_gw->orig_node == orig_dst_node)
 849                         goto out;
 850
 851                 /* If the dhcp packet has been sent to a different gw,
 852                  * we have to evaluate whether the old gw is still
 853                  * reliable enough
 854                  */
 855                 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
 856                                                 NULL);
 857                 if (!neigh_curr)
 858                         goto out;
 859
 860                 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
 861                                                       BATADV_IF_DEFAULT);
 862                 if (!curr_ifinfo)
 863                         goto out;
 864
 865                 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
 866                 batadv_neigh_ifinfo_free_ref(curr_ifinfo);
 867
 868                 break;
 869         case BATADV_GW_MODE_OFF:
 870         default:
 871                 goto out;
 872         }
 873
 874         neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
 875         if (!neigh_old)
 876                 goto out;
 877
 878         old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
 879         if (!old_ifinfo)
 880                 goto out;
 881
 882         if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
 883                 out_of_range = true;
 884         batadv_neigh_ifinfo_free_ref(old_ifinfo);
 885
 886 out:
 887         if (orig_dst_node)
 888                 batadv_orig_node_free_ref(orig_dst_node);
 889         if (curr_gw)
 890                 batadv_gw_node_free_ref(curr_gw);
 891         if (gw_node)
 892                 batadv_gw_node_free_ref(gw_node);
 893         if (neigh_old)
 894                 batadv_neigh_node_free_ref(neigh_old);
 895         if (neigh_curr)
 896                 batadv_neigh_node_free_ref(neigh_curr);
 897         return out_of_range;
 898 }