1/* Copyright (C) 2009-2014 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 "main.h" 19#include "sysfs.h" 20#include "gateway_client.h" 21#include "gateway_common.h" 22#include "hard-interface.h" 23#include "originator.h" 24#include "translation-table.h" 25#include "routing.h" 26#include <linux/ip.h> 27#include <linux/ipv6.h> 28#include <linux/udp.h> 29#include <linux/if_vlan.h> 30 31/* These are the offsets of the "hw type" and "hw address length" in the dhcp 32 * packet starting at the beginning of the dhcp header 33 */ 34#define BATADV_DHCP_HTYPE_OFFSET 1 35#define BATADV_DHCP_HLEN_OFFSET 2 36/* Value of htype representing Ethernet */ 37#define BATADV_DHCP_HTYPE_ETHERNET 0x01 38/* This is the offset of the "chaddr" field in the dhcp packet starting at the 39 * beginning of the dhcp header 40 */ 41#define BATADV_DHCP_CHADDR_OFFSET 28 42 43static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node) 44{ 45 if (atomic_dec_and_test(&gw_node->refcount)) { 46 batadv_orig_node_free_ref(gw_node->orig_node); 47 kfree_rcu(gw_node, rcu); 48 } 49} 50 51static struct batadv_gw_node * 52batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv) 53{ 54 struct batadv_gw_node *gw_node; 55 56 rcu_read_lock(); 57 gw_node = rcu_dereference(bat_priv->gw.curr_gw); 58 if (!gw_node) 59 goto out; 60 61 if (!atomic_inc_not_zero(&gw_node->refcount)) 62 gw_node = NULL; 63 64out: 65 rcu_read_unlock(); 66 return gw_node; 67} 68 69struct batadv_orig_node * 70batadv_gw_get_selected_orig(struct batadv_priv *bat_priv) 71{ 72 struct batadv_gw_node *gw_node; 73 struct batadv_orig_node *orig_node = NULL; 74 75 gw_node = batadv_gw_get_selected_gw_node(bat_priv); 76 if (!gw_node) 77 goto out; 78 79 rcu_read_lock(); 80 orig_node = gw_node->orig_node; 81 if (!orig_node) 82 goto unlock; 83 84 if (!atomic_inc_not_zero(&orig_node->refcount)) 85 orig_node = NULL; 86 87unlock: 88 rcu_read_unlock(); 89out: 90 if (gw_node) 91 batadv_gw_node_free_ref(gw_node); 92 return orig_node; 93} 94 95static void batadv_gw_select(struct batadv_priv *bat_priv, 96 struct batadv_gw_node *new_gw_node) 97{ 98 struct batadv_gw_node *curr_gw_node; 99 100 spin_lock_bh(&bat_priv->gw.list_lock); 101 102 if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount)) 103 new_gw_node = NULL; 104 105 curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1); 106 rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node); 107 108 if (curr_gw_node) 109 batadv_gw_node_free_ref(curr_gw_node); 110 111 spin_unlock_bh(&bat_priv->gw.list_lock); 112} 113 114/** 115 * batadv_gw_reselect - force a gateway reselection 116 * @bat_priv: the bat priv with all the soft interface information 117 * 118 * Set a flag to remind the GW component to perform a new gateway reselection. 119 * However this function does not ensure that the current gateway is going to be 120 * deselected. The reselection mechanism may elect the same gateway once again. 121 * 122 * This means that invoking batadv_gw_reselect() does not guarantee a gateway 123 * change and therefore a uevent is not necessarily expected. 124 */ 125void batadv_gw_reselect(struct batadv_priv *bat_priv) 126{ 127 atomic_set(&bat_priv->gw.reselect, 1); 128} 129 130static struct batadv_gw_node * 131batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv) 132{ 133 struct batadv_neigh_node *router; 134 struct batadv_neigh_ifinfo *router_ifinfo; 135 struct batadv_gw_node *gw_node, *curr_gw = NULL; 136 uint32_t max_gw_factor = 0, tmp_gw_factor = 0; 137 uint32_t gw_divisor; 138 uint8_t max_tq = 0; 139 uint8_t tq_avg; 140 struct batadv_orig_node *orig_node; 141 142 gw_divisor = BATADV_TQ_LOCAL_WINDOW_SIZE * BATADV_TQ_LOCAL_WINDOW_SIZE; 143 gw_divisor *= 64; 144 145 rcu_read_lock(); 146 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 147 if (gw_node->deleted) 148 continue; 149 150 orig_node = gw_node->orig_node; 151 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 152 if (!router) 153 continue; 154 155 router_ifinfo = batadv_neigh_ifinfo_get(router, 156 BATADV_IF_DEFAULT); 157 if (!router_ifinfo) 158 goto next; 159 160 if (!atomic_inc_not_zero(&gw_node->refcount)) 161 goto next; 162 163 tq_avg = router_ifinfo->bat_iv.tq_avg; 164 165 switch (atomic_read(&bat_priv->gw_sel_class)) { 166 case 1: /* fast connection */ 167 tmp_gw_factor = tq_avg * tq_avg; 168 tmp_gw_factor *= gw_node->bandwidth_down; 169 tmp_gw_factor *= 100 * 100; 170 tmp_gw_factor /= gw_divisor; 171 172 if ((tmp_gw_factor > max_gw_factor) || 173 ((tmp_gw_factor == max_gw_factor) && 174 (tq_avg > max_tq))) { 175 if (curr_gw) 176 batadv_gw_node_free_ref(curr_gw); 177 curr_gw = gw_node; 178 atomic_inc(&curr_gw->refcount); 179 } 180 break; 181 182 default: /* 2: stable connection (use best statistic) 183 * 3: fast-switch (use best statistic but change as 184 * soon as a better gateway appears) 185 * XX: late-switch (use best statistic but change as 186 * soon as a better gateway appears which has 187 * $routing_class more tq points) 188 */ 189 if (tq_avg > max_tq) { 190 if (curr_gw) 191 batadv_gw_node_free_ref(curr_gw); 192 curr_gw = gw_node; 193 atomic_inc(&curr_gw->refcount); 194 } 195 break; 196 } 197 198 if (tq_avg > max_tq) 199 max_tq = tq_avg; 200 201 if (tmp_gw_factor > max_gw_factor) 202 max_gw_factor = tmp_gw_factor; 203 204 batadv_gw_node_free_ref(gw_node); 205 206next: 207 batadv_neigh_node_free_ref(router); 208 if (router_ifinfo) 209 batadv_neigh_ifinfo_free_ref(router_ifinfo); 210 } 211 rcu_read_unlock(); 212 213 return curr_gw; 214} 215 216/** 217 * batadv_gw_check_client_stop - check if client mode has been switched off 218 * @bat_priv: the bat priv with all the soft interface information 219 * 220 * This function assumes the caller has checked that the gw state *is actually 221 * changing*. This function is not supposed to be called when there is no state 222 * change. 223 */ 224void batadv_gw_check_client_stop(struct batadv_priv *bat_priv) 225{ 226 struct batadv_gw_node *curr_gw; 227 228 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT) 229 return; 230 231 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 232 if (!curr_gw) 233 return; 234 235 /* deselect the current gateway so that next time that client mode is 236 * enabled a proper GW_ADD event can be sent 237 */ 238 batadv_gw_select(bat_priv, NULL); 239 240 /* if batman-adv is switching the gw client mode off and a gateway was 241 * already selected, send a DEL uevent 242 */ 243 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL); 244 245 batadv_gw_node_free_ref(curr_gw); 246} 247 248void batadv_gw_election(struct batadv_priv *bat_priv) 249{ 250 struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL; 251 struct batadv_neigh_node *router = NULL; 252 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 253 char gw_addr[18] = { '\0' }; 254 255 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT) 256 goto out; 257 258 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 259 260 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw) 261 goto out; 262 263 next_gw = batadv_gw_get_best_gw_node(bat_priv); 264 265 if (curr_gw == next_gw) 266 goto out; 267 268 if (next_gw) { 269 sprintf(gw_addr, "%pM", next_gw->orig_node->orig); 270 271 router = batadv_orig_router_get(next_gw->orig_node, 272 BATADV_IF_DEFAULT); 273 if (!router) { 274 batadv_gw_reselect(bat_priv); 275 goto out; 276 } 277 278 router_ifinfo = batadv_neigh_ifinfo_get(router, 279 BATADV_IF_DEFAULT); 280 if (!router_ifinfo) { 281 batadv_gw_reselect(bat_priv); 282 goto out; 283 } 284 } 285 286 if ((curr_gw) && (!next_gw)) { 287 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 288 "Removing selected gateway - no gateway in range\n"); 289 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, 290 NULL); 291 } else if ((!curr_gw) && (next_gw)) { 292 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 293 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 294 next_gw->orig_node->orig, 295 next_gw->bandwidth_down / 10, 296 next_gw->bandwidth_down % 10, 297 next_gw->bandwidth_up / 10, 298 next_gw->bandwidth_up % 10, 299 router_ifinfo->bat_iv.tq_avg); 300 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD, 301 gw_addr); 302 } else { 303 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 304 "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 305 next_gw->orig_node->orig, 306 next_gw->bandwidth_down / 10, 307 next_gw->bandwidth_down % 10, 308 next_gw->bandwidth_up / 10, 309 next_gw->bandwidth_up % 10, 310 router_ifinfo->bat_iv.tq_avg); 311 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE, 312 gw_addr); 313 } 314 315 batadv_gw_select(bat_priv, next_gw); 316 317out: 318 if (curr_gw) 319 batadv_gw_node_free_ref(curr_gw); 320 if (next_gw) 321 batadv_gw_node_free_ref(next_gw); 322 if (router) 323 batadv_neigh_node_free_ref(router); 324 if (router_ifinfo) 325 batadv_neigh_ifinfo_free_ref(router_ifinfo); 326} 327 328void batadv_gw_check_election(struct batadv_priv *bat_priv, 329 struct batadv_orig_node *orig_node) 330{ 331 struct batadv_neigh_ifinfo *router_orig_tq = NULL; 332 struct batadv_neigh_ifinfo *router_gw_tq = NULL; 333 struct batadv_orig_node *curr_gw_orig; 334 struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL; 335 uint8_t gw_tq_avg, orig_tq_avg; 336 337 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); 338 if (!curr_gw_orig) 339 goto reselect; 340 341 router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT); 342 if (!router_gw) 343 goto reselect; 344 345 router_gw_tq = batadv_neigh_ifinfo_get(router_gw, 346 BATADV_IF_DEFAULT); 347 if (!router_gw_tq) 348 goto reselect; 349 350 /* this node already is the gateway */ 351 if (curr_gw_orig == orig_node) 352 goto out; 353 354 router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 355 if (!router_orig) 356 goto out; 357 358 router_orig_tq = batadv_neigh_ifinfo_get(router_orig, 359 BATADV_IF_DEFAULT); 360 if (!router_orig_tq) 361 goto out; 362 363 gw_tq_avg = router_gw_tq->bat_iv.tq_avg; 364 orig_tq_avg = router_orig_tq->bat_iv.tq_avg; 365 366 /* the TQ value has to be better */ 367 if (orig_tq_avg < gw_tq_avg) 368 goto out; 369 370 /* if the routing class is greater than 3 the value tells us how much 371 * greater the TQ value of the new gateway must be 372 */ 373 if ((atomic_read(&bat_priv->gw_sel_class) > 3) && 374 (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class))) 375 goto out; 376 377 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 378 "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n", 379 gw_tq_avg, orig_tq_avg); 380 381reselect: 382 batadv_gw_reselect(bat_priv); 383out: 384 if (curr_gw_orig) 385 batadv_orig_node_free_ref(curr_gw_orig); 386 if (router_gw) 387 batadv_neigh_node_free_ref(router_gw); 388 if (router_orig) 389 batadv_neigh_node_free_ref(router_orig); 390 if (router_gw_tq) 391 batadv_neigh_ifinfo_free_ref(router_gw_tq); 392 if (router_orig_tq) 393 batadv_neigh_ifinfo_free_ref(router_orig_tq); 394} 395 396/** 397 * batadv_gw_node_add - add gateway node to list of available gateways 398 * @bat_priv: the bat priv with all the soft interface information 399 * @orig_node: originator announcing gateway capabilities 400 * @gateway: announced bandwidth information 401 */ 402static void batadv_gw_node_add(struct batadv_priv *bat_priv, 403 struct batadv_orig_node *orig_node, 404 struct batadv_tvlv_gateway_data *gateway) 405{ 406 struct batadv_gw_node *gw_node; 407 408 if (gateway->bandwidth_down == 0) 409 return; 410 411 if (!atomic_inc_not_zero(&orig_node->refcount)) 412 return; 413 414 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); 415 if (!gw_node) { 416 batadv_orig_node_free_ref(orig_node); 417 return; 418 } 419 420 INIT_HLIST_NODE(&gw_node->list); 421 gw_node->orig_node = orig_node; 422 atomic_set(&gw_node->refcount, 1); 423 424 spin_lock_bh(&bat_priv->gw.list_lock); 425 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list); 426 spin_unlock_bh(&bat_priv->gw.list_lock); 427 428 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 429 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", 430 orig_node->orig, 431 ntohl(gateway->bandwidth_down) / 10, 432 ntohl(gateway->bandwidth_down) % 10, 433 ntohl(gateway->bandwidth_up) / 10, 434 ntohl(gateway->bandwidth_up) % 10); 435} 436 437/** 438 * batadv_gw_node_get - retrieve gateway node from list of available gateways 439 * @bat_priv: the bat priv with all the soft interface information 440 * @orig_node: originator announcing gateway capabilities 441 * 442 * Returns gateway node if found or NULL otherwise. 443 */ 444static struct batadv_gw_node * 445batadv_gw_node_get(struct batadv_priv *bat_priv, 446 struct batadv_orig_node *orig_node) 447{ 448 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL; 449 450 rcu_read_lock(); 451 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) { 452 if (gw_node_tmp->orig_node != orig_node) 453 continue; 454 455 if (gw_node_tmp->deleted) 456 continue; 457 458 if (!atomic_inc_not_zero(&gw_node_tmp->refcount)) 459 continue; 460 461 gw_node = gw_node_tmp; 462 break; 463 } 464 rcu_read_unlock(); 465 466 return gw_node; 467} 468 469/** 470 * batadv_gw_node_update - update list of available gateways with changed 471 * bandwidth information 472 * @bat_priv: the bat priv with all the soft interface information 473 * @orig_node: originator announcing gateway capabilities 474 * @gateway: announced bandwidth information 475 */ 476void batadv_gw_node_update(struct batadv_priv *bat_priv, 477 struct batadv_orig_node *orig_node, 478 struct batadv_tvlv_gateway_data *gateway) 479{ 480 struct batadv_gw_node *gw_node, *curr_gw = NULL; 481 482 gw_node = batadv_gw_node_get(bat_priv, orig_node); 483 if (!gw_node) { 484 batadv_gw_node_add(bat_priv, orig_node, gateway); 485 goto out; 486 } 487 488 if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) && 489 (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))) 490 goto out; 491 492 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 493 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n", 494 orig_node->orig, 495 gw_node->bandwidth_down / 10, 496 gw_node->bandwidth_down % 10, 497 gw_node->bandwidth_up / 10, 498 gw_node->bandwidth_up % 10, 499 ntohl(gateway->bandwidth_down) / 10, 500 ntohl(gateway->bandwidth_down) % 10, 501 ntohl(gateway->bandwidth_up) / 10, 502 ntohl(gateway->bandwidth_up) % 10); 503 504 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 505 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 506 507 gw_node->deleted = 0; 508 if (ntohl(gateway->bandwidth_down) == 0) { 509 gw_node->deleted = jiffies; 510 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 511 "Gateway %pM removed from gateway list\n", 512 orig_node->orig); 513 514 /* Note: We don't need a NULL check here, since curr_gw never 515 * gets dereferenced. 516 */ 517 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 518 if (gw_node == curr_gw) 519 batadv_gw_reselect(bat_priv); 520 } 521 522out: 523 if (curr_gw) 524 batadv_gw_node_free_ref(curr_gw); 525 if (gw_node) 526 batadv_gw_node_free_ref(gw_node); 527} 528 529void batadv_gw_node_delete(struct batadv_priv *bat_priv, 530 struct batadv_orig_node *orig_node) 531{ 532 struct batadv_tvlv_gateway_data gateway; 533 534 gateway.bandwidth_down = 0; 535 gateway.bandwidth_up = 0; 536 537 batadv_gw_node_update(bat_priv, orig_node, &gateway); 538} 539 540void batadv_gw_node_purge(struct batadv_priv *bat_priv) 541{ 542 struct batadv_gw_node *gw_node, *curr_gw; 543 struct hlist_node *node_tmp; 544 unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT); 545 int do_reselect = 0; 546 547 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 548 549 spin_lock_bh(&bat_priv->gw.list_lock); 550 551 hlist_for_each_entry_safe(gw_node, node_tmp, 552 &bat_priv->gw.list, list) { 553 if (((!gw_node->deleted) || 554 (time_before(jiffies, gw_node->deleted + timeout))) && 555 atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE) 556 continue; 557 558 if (curr_gw == gw_node) 559 do_reselect = 1; 560 561 hlist_del_rcu(&gw_node->list); 562 batadv_gw_node_free_ref(gw_node); 563 } 564 565 spin_unlock_bh(&bat_priv->gw.list_lock); 566 567 /* gw_reselect() needs to acquire the gw_list_lock */ 568 if (do_reselect) 569 batadv_gw_reselect(bat_priv); 570 571 if (curr_gw) 572 batadv_gw_node_free_ref(curr_gw); 573} 574 575/* fails if orig_node has no router */ 576static 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); 608out: 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 616int 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 if (gw_node->deleted) 637 continue; 638 639 /* fails if orig_node has no router */ 640 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0) 641 continue; 642 643 gw_count++; 644 } 645 rcu_read_unlock(); 646 647 if (gw_count == 0) 648 seq_puts(seq, "No gateways in range ...\n"); 649 650out: 651 if (primary_if) 652 batadv_hardif_free_ref(primary_if); 653 return 0; 654} 655 656/** 657 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message 658 * @skb: the packet to check 659 * @header_len: a pointer to the batman-adv header size 660 * @chaddr: buffer where the client address will be stored. Valid 661 * only if the function returns BATADV_DHCP_TO_CLIENT 662 * 663 * Returns: 664 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error 665 * while parsing it 666 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server 667 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client 668 * 669 * This function may re-allocate the data buffer of the skb passed as argument. 670 */ 671enum batadv_dhcp_recipient 672batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, 673 uint8_t *chaddr) 674{ 675 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO; 676 struct ethhdr *ethhdr; 677 struct iphdr *iphdr; 678 struct ipv6hdr *ipv6hdr; 679 struct udphdr *udphdr; 680 struct vlan_ethhdr *vhdr; 681 int chaddr_offset; 682 __be16 proto; 683 uint8_t *p; 684 685 /* check for ethernet header */ 686 if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) 687 return BATADV_DHCP_NO; 688 689 ethhdr = eth_hdr(skb); 690 proto = ethhdr->h_proto; 691 *header_len += ETH_HLEN; 692 693 /* check for initial vlan header */ 694 if (proto == htons(ETH_P_8021Q)) { 695 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) 696 return BATADV_DHCP_NO; 697 698 vhdr = vlan_eth_hdr(skb); 699 proto = vhdr->h_vlan_encapsulated_proto; 700 *header_len += VLAN_HLEN; 701 } 702 703 /* check for ip header */ 704 switch (proto) { 705 case htons(ETH_P_IP): 706 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) 707 return BATADV_DHCP_NO; 708 709 iphdr = (struct iphdr *)(skb->data + *header_len); 710 *header_len += iphdr->ihl * 4; 711 712 /* check for udp header */ 713 if (iphdr->protocol != IPPROTO_UDP) 714 return BATADV_DHCP_NO; 715 716 break; 717 case htons(ETH_P_IPV6): 718 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) 719 return BATADV_DHCP_NO; 720 721 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); 722 *header_len += sizeof(*ipv6hdr); 723 724 /* check for udp header */ 725 if (ipv6hdr->nexthdr != IPPROTO_UDP) 726 return BATADV_DHCP_NO; 727 728 break; 729 default: 730 return BATADV_DHCP_NO; 731 } 732 733 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) 734 return BATADV_DHCP_NO; 735 736 /* skb->data might have been reallocated by pskb_may_pull() */ 737 ethhdr = eth_hdr(skb); 738 if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) 739 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN); 740 741 udphdr = (struct udphdr *)(skb->data + *header_len); 742 *header_len += sizeof(*udphdr); 743 744 /* check for bootp port */ 745 switch (proto) { 746 case htons(ETH_P_IP): 747 if (udphdr->dest == htons(67)) 748 ret = BATADV_DHCP_TO_SERVER; 749 else if (udphdr->source == htons(67)) 750 ret = BATADV_DHCP_TO_CLIENT; 751 break; 752 case htons(ETH_P_IPV6): 753 if (udphdr->dest == htons(547)) 754 ret = BATADV_DHCP_TO_SERVER; 755 else if (udphdr->source == htons(547)) 756 ret = BATADV_DHCP_TO_CLIENT; 757 break; 758 } 759 760 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; 761 /* store the client address if the message is going to a client */ 762 if (ret == BATADV_DHCP_TO_CLIENT && 763 pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { 764 /* check if the DHCP packet carries an Ethernet DHCP */ 765 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; 766 if (*p != BATADV_DHCP_HTYPE_ETHERNET) 767 return BATADV_DHCP_NO; 768 769 /* check if the DHCP packet carries a valid Ethernet address */ 770 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET; 771 if (*p != ETH_ALEN) 772 return BATADV_DHCP_NO; 773 774 ether_addr_copy(chaddr, skb->data + chaddr_offset); 775 } 776 777 return ret; 778} 779 780/** 781 * batadv_gw_out_of_range - check if the dhcp request destination is the best gw 782 * @bat_priv: the bat priv with all the soft interface information 783 * @skb: the outgoing packet 784 * 785 * Check if the skb is a DHCP request and if it is sent to the current best GW 786 * server. Due to topology changes it may be the case that the GW server 787 * previously selected is not the best one anymore. 788 * 789 * Returns true if the packet destination is unicast and it is not the best gw, 790 * false otherwise. 791 * 792 * This call might reallocate skb data. 793 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER. 794 */ 795bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, 796 struct sk_buff *skb) 797{ 798 struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL; 799 struct batadv_orig_node *orig_dst_node = NULL; 800 struct batadv_gw_node *gw_node = NULL, *curr_gw = NULL; 801 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; 802 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 803 bool out_of_range = false; 804 uint8_t curr_tq_avg; 805 unsigned short vid; 806 807 vid = batadv_get_vid(skb, 0); 808 809 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 810 ethhdr->h_dest, vid); 811 if (!orig_dst_node) 812 goto out; 813 814 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node); 815 if (!gw_node) 816 goto out; 817 818 switch (atomic_read(&bat_priv->gw_mode)) { 819 case BATADV_GW_MODE_SERVER: 820 /* If we are a GW then we are our best GW. We can artificially 821 * set the tq towards ourself as the maximum value 822 */ 823 curr_tq_avg = BATADV_TQ_MAX_VALUE; 824 break; 825 case BATADV_GW_MODE_CLIENT: 826 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 827 if (!curr_gw) 828 goto out; 829 830 /* packet is going to our gateway */ 831 if (curr_gw->orig_node == orig_dst_node) 832 goto out; 833 834 /* If the dhcp packet has been sent to a different gw, 835 * we have to evaluate whether the old gw is still 836 * reliable enough 837 */ 838 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node, 839 NULL); 840 if (!neigh_curr) 841 goto out; 842 843 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr, 844 BATADV_IF_DEFAULT); 845 if (!curr_ifinfo) 846 goto out; 847 848 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg; 849 batadv_neigh_ifinfo_free_ref(curr_ifinfo); 850 851 break; 852 case BATADV_GW_MODE_OFF: 853 default: 854 goto out; 855 } 856 857 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL); 858 if (!neigh_old) 859 goto out; 860 861 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT); 862 if (!old_ifinfo) 863 goto out; 864 865 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD) 866 out_of_range = true; 867 batadv_neigh_ifinfo_free_ref(old_ifinfo); 868 869out: 870 if (orig_dst_node) 871 batadv_orig_node_free_ref(orig_dst_node); 872 if (curr_gw) 873 batadv_gw_node_free_ref(curr_gw); 874 if (gw_node) 875 batadv_gw_node_free_ref(gw_node); 876 if (neigh_old) 877 batadv_neigh_node_free_ref(neigh_old); 878 if (neigh_curr) 879 batadv_neigh_node_free_ref(neigh_curr); 880 return out_of_range; 881} 882