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