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 43 static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node) 44 { 45 if (atomic_dec_and_test(&gw_node->refcount)) 46 kfree_rcu(gw_node, rcu); 47 } 48 49 static struct batadv_gw_node * 50 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv) 51 { 52 struct batadv_gw_node *gw_node; 53 54 rcu_read_lock(); 55 gw_node = rcu_dereference(bat_priv->gw.curr_gw); 56 if (!gw_node) 57 goto out; 58 59 if (!atomic_inc_not_zero(&gw_node->refcount)) 60 gw_node = NULL; 61 62 out: 63 rcu_read_unlock(); 64 return gw_node; 65 } 66 67 struct batadv_orig_node * 68 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv) 69 { 70 struct batadv_gw_node *gw_node; 71 struct batadv_orig_node *orig_node = NULL; 72 73 gw_node = batadv_gw_get_selected_gw_node(bat_priv); 74 if (!gw_node) 75 goto out; 76 77 rcu_read_lock(); 78 orig_node = gw_node->orig_node; 79 if (!orig_node) 80 goto unlock; 81 82 if (!atomic_inc_not_zero(&orig_node->refcount)) 83 orig_node = NULL; 84 85 unlock: 86 rcu_read_unlock(); 87 out: 88 if (gw_node) 89 batadv_gw_node_free_ref(gw_node); 90 return orig_node; 91 } 92 93 static void batadv_gw_select(struct batadv_priv *bat_priv, 94 struct batadv_gw_node *new_gw_node) 95 { 96 struct batadv_gw_node *curr_gw_node; 97 98 spin_lock_bh(&bat_priv->gw.list_lock); 99 100 if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount)) 101 new_gw_node = NULL; 102 103 curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1); 104 rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node); 105 106 if (curr_gw_node) 107 batadv_gw_node_free_ref(curr_gw_node); 108 109 spin_unlock_bh(&bat_priv->gw.list_lock); 110 } 111 112 /** 113 * batadv_gw_reselect - force a gateway reselection 114 * @bat_priv: the bat priv with all the soft interface information 115 * 116 * Set a flag to remind the GW component to perform a new gateway reselection. 117 * However this function does not ensure that the current gateway is going to be 118 * deselected. The reselection mechanism may elect the same gateway once again. 119 * 120 * This means that invoking batadv_gw_reselect() does not guarantee a gateway 121 * change and therefore a uevent is not necessarily expected. 122 */ 123 void batadv_gw_reselect(struct batadv_priv *bat_priv) 124 { 125 atomic_set(&bat_priv->gw.reselect, 1); 126 } 127 128 static struct batadv_gw_node * 129 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv) 130 { 131 struct batadv_neigh_node *router; 132 struct batadv_neigh_ifinfo *router_ifinfo; 133 struct batadv_gw_node *gw_node, *curr_gw = NULL; 134 uint32_t max_gw_factor = 0, tmp_gw_factor = 0; 135 uint32_t gw_divisor; 136 uint8_t max_tq = 0; 137 uint8_t tq_avg; 138 struct batadv_orig_node *orig_node; 139 140 gw_divisor = BATADV_TQ_LOCAL_WINDOW_SIZE * BATADV_TQ_LOCAL_WINDOW_SIZE; 141 gw_divisor *= 64; 142 143 rcu_read_lock(); 144 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 145 if (gw_node->deleted) 146 continue; 147 148 orig_node = gw_node->orig_node; 149 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 150 if (!router) 151 continue; 152 153 router_ifinfo = batadv_neigh_ifinfo_get(router, 154 BATADV_IF_DEFAULT); 155 if (!router_ifinfo) 156 goto next; 157 158 if (!atomic_inc_not_zero(&gw_node->refcount)) 159 goto next; 160 161 tq_avg = router_ifinfo->bat_iv.tq_avg; 162 163 switch (atomic_read(&bat_priv->gw_sel_class)) { 164 case 1: /* fast connection */ 165 tmp_gw_factor = tq_avg * tq_avg; 166 tmp_gw_factor *= gw_node->bandwidth_down; 167 tmp_gw_factor *= 100 * 100; 168 tmp_gw_factor /= gw_divisor; 169 170 if ((tmp_gw_factor > max_gw_factor) || 171 ((tmp_gw_factor == max_gw_factor) && 172 (tq_avg > max_tq))) { 173 if (curr_gw) 174 batadv_gw_node_free_ref(curr_gw); 175 curr_gw = gw_node; 176 atomic_inc(&curr_gw->refcount); 177 } 178 break; 179 180 default: /* 2: stable connection (use best statistic) 181 * 3: fast-switch (use best statistic but change as 182 * soon as a better gateway appears) 183 * XX: late-switch (use best statistic but change as 184 * soon as a better gateway appears which has 185 * $routing_class more tq points) 186 */ 187 if (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 } 195 196 if (tq_avg > max_tq) 197 max_tq = tq_avg; 198 199 if (tmp_gw_factor > max_gw_factor) 200 max_gw_factor = tmp_gw_factor; 201 202 batadv_gw_node_free_ref(gw_node); 203 204 next: 205 batadv_neigh_node_free_ref(router); 206 if (router_ifinfo) 207 batadv_neigh_ifinfo_free_ref(router_ifinfo); 208 } 209 rcu_read_unlock(); 210 211 return curr_gw; 212 } 213 214 /** 215 * batadv_gw_check_client_stop - check if client mode has been switched off 216 * @bat_priv: the bat priv with all the soft interface information 217 * 218 * This function assumes the caller has checked that the gw state *is actually 219 * changing*. This function is not supposed to be called when there is no state 220 * change. 221 */ 222 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv) 223 { 224 struct batadv_gw_node *curr_gw; 225 226 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT) 227 return; 228 229 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 230 if (!curr_gw) 231 return; 232 233 /* deselect the current gateway so that next time that client mode is 234 * enabled a proper GW_ADD event can be sent 235 */ 236 batadv_gw_select(bat_priv, NULL); 237 238 /* if batman-adv is switching the gw client mode off and a gateway was 239 * already selected, send a DEL uevent 240 */ 241 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL); 242 243 batadv_gw_node_free_ref(curr_gw); 244 } 245 246 void batadv_gw_election(struct batadv_priv *bat_priv) 247 { 248 struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL; 249 struct batadv_neigh_node *router = NULL; 250 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 251 char gw_addr[18] = { '\0' }; 252 253 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT) 254 goto out; 255 256 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 257 258 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw) 259 goto out; 260 261 next_gw = batadv_gw_get_best_gw_node(bat_priv); 262 263 if (curr_gw == next_gw) 264 goto out; 265 266 if (next_gw) { 267 sprintf(gw_addr, "%pM", next_gw->orig_node->orig); 268 269 router = batadv_orig_router_get(next_gw->orig_node, 270 BATADV_IF_DEFAULT); 271 if (!router) { 272 batadv_gw_reselect(bat_priv); 273 goto out; 274 } 275 276 router_ifinfo = batadv_neigh_ifinfo_get(router, 277 BATADV_IF_DEFAULT); 278 if (!router_ifinfo) { 279 batadv_gw_reselect(bat_priv); 280 goto out; 281 } 282 } 283 284 if ((curr_gw) && (!next_gw)) { 285 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 286 "Removing selected gateway - no gateway in range\n"); 287 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, 288 NULL); 289 } else if ((!curr_gw) && (next_gw)) { 290 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 291 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 292 next_gw->orig_node->orig, 293 next_gw->bandwidth_down / 10, 294 next_gw->bandwidth_down % 10, 295 next_gw->bandwidth_up / 10, 296 next_gw->bandwidth_up % 10, 297 router_ifinfo->bat_iv.tq_avg); 298 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD, 299 gw_addr); 300 } else { 301 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 302 "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 303 next_gw->orig_node->orig, 304 next_gw->bandwidth_down / 10, 305 next_gw->bandwidth_down % 10, 306 next_gw->bandwidth_up / 10, 307 next_gw->bandwidth_up % 10, 308 router_ifinfo->bat_iv.tq_avg); 309 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE, 310 gw_addr); 311 } 312 313 batadv_gw_select(bat_priv, next_gw); 314 315 out: 316 if (curr_gw) 317 batadv_gw_node_free_ref(curr_gw); 318 if (next_gw) 319 batadv_gw_node_free_ref(next_gw); 320 if (router) 321 batadv_neigh_node_free_ref(router); 322 if (router_ifinfo) 323 batadv_neigh_ifinfo_free_ref(router_ifinfo); 324 } 325 326 void batadv_gw_check_election(struct batadv_priv *bat_priv, 327 struct batadv_orig_node *orig_node) 328 { 329 struct batadv_neigh_ifinfo *router_orig_tq = NULL; 330 struct batadv_neigh_ifinfo *router_gw_tq = NULL; 331 struct batadv_orig_node *curr_gw_orig; 332 struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL; 333 uint8_t gw_tq_avg, orig_tq_avg; 334 335 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); 336 if (!curr_gw_orig) 337 goto reselect; 338 339 router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT); 340 if (!router_gw) 341 goto reselect; 342 343 router_gw_tq = batadv_neigh_ifinfo_get(router_gw, 344 BATADV_IF_DEFAULT); 345 if (!router_gw_tq) 346 goto reselect; 347 348 /* this node already is the gateway */ 349 if (curr_gw_orig == orig_node) 350 goto out; 351 352 router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 353 if (!router_orig) 354 goto out; 355 356 router_orig_tq = batadv_neigh_ifinfo_get(router_orig, 357 BATADV_IF_DEFAULT); 358 if (!router_orig_tq) 359 goto out; 360 361 gw_tq_avg = router_gw_tq->bat_iv.tq_avg; 362 orig_tq_avg = router_orig_tq->bat_iv.tq_avg; 363 364 /* the TQ value has to be better */ 365 if (orig_tq_avg < gw_tq_avg) 366 goto out; 367 368 /* if the routing class is greater than 3 the value tells us how much 369 * greater the TQ value of the new gateway must be 370 */ 371 if ((atomic_read(&bat_priv->gw_sel_class) > 3) && 372 (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class))) 373 goto out; 374 375 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 376 "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n", 377 gw_tq_avg, orig_tq_avg); 378 379 reselect: 380 batadv_gw_reselect(bat_priv); 381 out: 382 if (curr_gw_orig) 383 batadv_orig_node_free_ref(curr_gw_orig); 384 if (router_gw) 385 batadv_neigh_node_free_ref(router_gw); 386 if (router_orig) 387 batadv_neigh_node_free_ref(router_orig); 388 if (router_gw_tq) 389 batadv_neigh_ifinfo_free_ref(router_gw_tq); 390 if (router_orig_tq) 391 batadv_neigh_ifinfo_free_ref(router_orig_tq); 392 } 393 394 /** 395 * batadv_gw_node_add - add gateway node to list of available gateways 396 * @bat_priv: the bat priv with all the soft interface information 397 * @orig_node: originator announcing gateway capabilities 398 * @gateway: announced bandwidth information 399 */ 400 static void batadv_gw_node_add(struct batadv_priv *bat_priv, 401 struct batadv_orig_node *orig_node, 402 struct batadv_tvlv_gateway_data *gateway) 403 { 404 struct batadv_gw_node *gw_node; 405 406 if (gateway->bandwidth_down == 0) 407 return; 408 409 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); 410 if (!gw_node) 411 return; 412 413 INIT_HLIST_NODE(&gw_node->list); 414 gw_node->orig_node = orig_node; 415 atomic_set(&gw_node->refcount, 1); 416 417 spin_lock_bh(&bat_priv->gw.list_lock); 418 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list); 419 spin_unlock_bh(&bat_priv->gw.list_lock); 420 421 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 422 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", 423 orig_node->orig, 424 ntohl(gateway->bandwidth_down) / 10, 425 ntohl(gateway->bandwidth_down) % 10, 426 ntohl(gateway->bandwidth_up) / 10, 427 ntohl(gateway->bandwidth_up) % 10); 428 } 429 430 /** 431 * batadv_gw_node_get - retrieve gateway node from list of available gateways 432 * @bat_priv: the bat priv with all the soft interface information 433 * @orig_node: originator announcing gateway capabilities 434 * 435 * Returns gateway node if found or NULL otherwise. 436 */ 437 static struct batadv_gw_node * 438 batadv_gw_node_get(struct batadv_priv *bat_priv, 439 struct batadv_orig_node *orig_node) 440 { 441 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL; 442 443 rcu_read_lock(); 444 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) { 445 if (gw_node_tmp->orig_node != orig_node) 446 continue; 447 448 if (gw_node_tmp->deleted) 449 continue; 450 451 if (!atomic_inc_not_zero(&gw_node_tmp->refcount)) 452 continue; 453 454 gw_node = gw_node_tmp; 455 break; 456 } 457 rcu_read_unlock(); 458 459 return gw_node; 460 } 461 462 /** 463 * batadv_gw_node_update - update list of available gateways with changed 464 * bandwidth information 465 * @bat_priv: the bat priv with all the soft interface information 466 * @orig_node: originator announcing gateway capabilities 467 * @gateway: announced bandwidth information 468 */ 469 void batadv_gw_node_update(struct batadv_priv *bat_priv, 470 struct batadv_orig_node *orig_node, 471 struct batadv_tvlv_gateway_data *gateway) 472 { 473 struct batadv_gw_node *gw_node, *curr_gw = NULL; 474 475 gw_node = batadv_gw_node_get(bat_priv, orig_node); 476 if (!gw_node) { 477 batadv_gw_node_add(bat_priv, orig_node, gateway); 478 goto out; 479 } 480 481 if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) && 482 (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))) 483 goto out; 484 485 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 486 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n", 487 orig_node->orig, 488 gw_node->bandwidth_down / 10, 489 gw_node->bandwidth_down % 10, 490 gw_node->bandwidth_up / 10, 491 gw_node->bandwidth_up % 10, 492 ntohl(gateway->bandwidth_down) / 10, 493 ntohl(gateway->bandwidth_down) % 10, 494 ntohl(gateway->bandwidth_up) / 10, 495 ntohl(gateway->bandwidth_up) % 10); 496 497 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 498 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 499 500 gw_node->deleted = 0; 501 if (ntohl(gateway->bandwidth_down) == 0) { 502 gw_node->deleted = jiffies; 503 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 504 "Gateway %pM removed from gateway list\n", 505 orig_node->orig); 506 507 /* Note: We don't need a NULL check here, since curr_gw never 508 * gets dereferenced. 509 */ 510 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 511 if (gw_node == curr_gw) 512 batadv_gw_reselect(bat_priv); 513 } 514 515 out: 516 if (curr_gw) 517 batadv_gw_node_free_ref(curr_gw); 518 if (gw_node) 519 batadv_gw_node_free_ref(gw_node); 520 } 521 522 void batadv_gw_node_delete(struct batadv_priv *bat_priv, 523 struct batadv_orig_node *orig_node) 524 { 525 struct batadv_tvlv_gateway_data gateway; 526 527 gateway.bandwidth_down = 0; 528 gateway.bandwidth_up = 0; 529 530 batadv_gw_node_update(bat_priv, orig_node, &gateway); 531 } 532 533 void batadv_gw_node_purge(struct batadv_priv *bat_priv) 534 { 535 struct batadv_gw_node *gw_node, *curr_gw; 536 struct hlist_node *node_tmp; 537 unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT); 538 int do_reselect = 0; 539 540 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 541 542 spin_lock_bh(&bat_priv->gw.list_lock); 543 544 hlist_for_each_entry_safe(gw_node, node_tmp, 545 &bat_priv->gw.list, list) { 546 if (((!gw_node->deleted) || 547 (time_before(jiffies, gw_node->deleted + timeout))) && 548 atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE) 549 continue; 550 551 if (curr_gw == gw_node) 552 do_reselect = 1; 553 554 hlist_del_rcu(&gw_node->list); 555 batadv_gw_node_free_ref(gw_node); 556 } 557 558 spin_unlock_bh(&bat_priv->gw.list_lock); 559 560 /* gw_reselect() needs to acquire the gw_list_lock */ 561 if (do_reselect) 562 batadv_gw_reselect(bat_priv); 563 564 if (curr_gw) 565 batadv_gw_node_free_ref(curr_gw); 566 } 567 568 /* fails if orig_node has no router */ 569 static int batadv_write_buffer_text(struct batadv_priv *bat_priv, 570 struct seq_file *seq, 571 const struct batadv_gw_node *gw_node) 572 { 573 struct batadv_gw_node *curr_gw; 574 struct batadv_neigh_node *router; 575 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 576 int ret = -1; 577 578 router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT); 579 if (!router) 580 goto out; 581 582 router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT); 583 if (!router_ifinfo) 584 goto out; 585 586 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 587 588 ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n", 589 (curr_gw == gw_node ? "=>" : " "), 590 gw_node->orig_node->orig, 591 router_ifinfo->bat_iv.tq_avg, router->addr, 592 router->if_incoming->net_dev->name, 593 gw_node->bandwidth_down / 10, 594 gw_node->bandwidth_down % 10, 595 gw_node->bandwidth_up / 10, 596 gw_node->bandwidth_up % 10); 597 598 if (curr_gw) 599 batadv_gw_node_free_ref(curr_gw); 600 out: 601 if (router_ifinfo) 602 batadv_neigh_ifinfo_free_ref(router_ifinfo); 603 if (router) 604 batadv_neigh_node_free_ref(router); 605 return ret; 606 } 607 608 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset) 609 { 610 struct net_device *net_dev = (struct net_device *)seq->private; 611 struct batadv_priv *bat_priv = netdev_priv(net_dev); 612 struct batadv_hard_iface *primary_if; 613 struct batadv_gw_node *gw_node; 614 int gw_count = 0; 615 616 primary_if = batadv_seq_print_text_primary_if_get(seq); 617 if (!primary_if) 618 goto out; 619 620 seq_printf(seq, 621 " %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n", 622 "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF", 623 BATADV_SOURCE_VERSION, primary_if->net_dev->name, 624 primary_if->net_dev->dev_addr, net_dev->name); 625 626 rcu_read_lock(); 627 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 628 if (gw_node->deleted) 629 continue; 630 631 /* fails if orig_node has no router */ 632 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0) 633 continue; 634 635 gw_count++; 636 } 637 rcu_read_unlock(); 638 639 if (gw_count == 0) 640 seq_puts(seq, "No gateways in range ...\n"); 641 642 out: 643 if (primary_if) 644 batadv_hardif_free_ref(primary_if); 645 return 0; 646 } 647 648 /** 649 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message 650 * @skb: the packet to check 651 * @header_len: a pointer to the batman-adv header size 652 * @chaddr: buffer where the client address will be stored. Valid 653 * only if the function returns BATADV_DHCP_TO_CLIENT 654 * 655 * Returns: 656 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error 657 * while parsing it 658 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server 659 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client 660 * 661 * This function may re-allocate the data buffer of the skb passed as argument. 662 */ 663 enum batadv_dhcp_recipient 664 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, 665 uint8_t *chaddr) 666 { 667 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO; 668 struct ethhdr *ethhdr; 669 struct iphdr *iphdr; 670 struct ipv6hdr *ipv6hdr; 671 struct udphdr *udphdr; 672 struct vlan_ethhdr *vhdr; 673 int chaddr_offset; 674 __be16 proto; 675 uint8_t *p; 676 677 /* check for ethernet header */ 678 if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) 679 return BATADV_DHCP_NO; 680 681 ethhdr = eth_hdr(skb); 682 proto = ethhdr->h_proto; 683 *header_len += ETH_HLEN; 684 685 /* check for initial vlan header */ 686 if (proto == htons(ETH_P_8021Q)) { 687 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) 688 return BATADV_DHCP_NO; 689 690 vhdr = vlan_eth_hdr(skb); 691 proto = vhdr->h_vlan_encapsulated_proto; 692 *header_len += VLAN_HLEN; 693 } 694 695 /* check for ip header */ 696 switch (proto) { 697 case htons(ETH_P_IP): 698 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) 699 return BATADV_DHCP_NO; 700 701 iphdr = (struct iphdr *)(skb->data + *header_len); 702 *header_len += iphdr->ihl * 4; 703 704 /* check for udp header */ 705 if (iphdr->protocol != IPPROTO_UDP) 706 return BATADV_DHCP_NO; 707 708 break; 709 case htons(ETH_P_IPV6): 710 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) 711 return BATADV_DHCP_NO; 712 713 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); 714 *header_len += sizeof(*ipv6hdr); 715 716 /* check for udp header */ 717 if (ipv6hdr->nexthdr != IPPROTO_UDP) 718 return BATADV_DHCP_NO; 719 720 break; 721 default: 722 return BATADV_DHCP_NO; 723 } 724 725 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) 726 return BATADV_DHCP_NO; 727 728 /* skb->data might have been reallocated by pskb_may_pull() */ 729 ethhdr = eth_hdr(skb); 730 if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) 731 ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN); 732 733 udphdr = (struct udphdr *)(skb->data + *header_len); 734 *header_len += sizeof(*udphdr); 735 736 /* check for bootp port */ 737 switch (proto) { 738 case htons(ETH_P_IP): 739 if (udphdr->dest == htons(67)) 740 ret = BATADV_DHCP_TO_SERVER; 741 else if (udphdr->source == htons(67)) 742 ret = BATADV_DHCP_TO_CLIENT; 743 break; 744 case htons(ETH_P_IPV6): 745 if (udphdr->dest == htons(547)) 746 ret = BATADV_DHCP_TO_SERVER; 747 else if (udphdr->source == htons(547)) 748 ret = BATADV_DHCP_TO_CLIENT; 749 break; 750 } 751 752 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; 753 /* store the client address if the message is going to a client */ 754 if (ret == BATADV_DHCP_TO_CLIENT && 755 pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { 756 /* check if the DHCP packet carries an Ethernet DHCP */ 757 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; 758 if (*p != BATADV_DHCP_HTYPE_ETHERNET) 759 return BATADV_DHCP_NO; 760 761 /* check if the DHCP packet carries a valid Ethernet address */ 762 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET; 763 if (*p != ETH_ALEN) 764 return BATADV_DHCP_NO; 765 766 ether_addr_copy(chaddr, skb->data + chaddr_offset); 767 } 768 769 return ret; 770 } 771 /** 772 * batadv_gw_out_of_range - check if the dhcp request destination is the best gw 773 * @bat_priv: the bat priv with all the soft interface information 774 * @skb: the outgoing packet 775 * 776 * Check if the skb is a DHCP request and if it is sent to the current best GW 777 * server. Due to topology changes it may be the case that the GW server 778 * previously selected is not the best one anymore. 779 * 780 * Returns true if the packet destination is unicast and it is not the best gw, 781 * false otherwise. 782 * 783 * This call might reallocate skb data. 784 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER. 785 */ 786 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, 787 struct sk_buff *skb) 788 { 789 struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL; 790 struct batadv_orig_node *orig_dst_node = NULL; 791 struct batadv_gw_node *gw_node = NULL, *curr_gw = NULL; 792 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; 793 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 794 bool out_of_range = false; 795 uint8_t curr_tq_avg; 796 unsigned short vid; 797 798 vid = batadv_get_vid(skb, 0); 799 800 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 801 ethhdr->h_dest, vid); 802 if (!orig_dst_node) 803 goto out; 804 805 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node); 806 if (!gw_node->bandwidth_down == 0) 807 goto out; 808 809 switch (atomic_read(&bat_priv->gw_mode)) { 810 case BATADV_GW_MODE_SERVER: 811 /* If we are a GW then we are our best GW. We can artificially 812 * set the tq towards ourself as the maximum value 813 */ 814 curr_tq_avg = BATADV_TQ_MAX_VALUE; 815 break; 816 case BATADV_GW_MODE_CLIENT: 817 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 818 if (!curr_gw) 819 goto out; 820 821 /* packet is going to our gateway */ 822 if (curr_gw->orig_node == orig_dst_node) 823 goto out; 824 825 /* If the dhcp packet has been sent to a different gw, 826 * we have to evaluate whether the old gw is still 827 * reliable enough 828 */ 829 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node, 830 NULL); 831 if (!neigh_curr) 832 goto out; 833 834 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr, 835 BATADV_IF_DEFAULT); 836 if (!curr_ifinfo) 837 goto out; 838 839 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg; 840 batadv_neigh_ifinfo_free_ref(curr_ifinfo); 841 842 break; 843 case BATADV_GW_MODE_OFF: 844 default: 845 goto out; 846 } 847 848 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL); 849 if (!neigh_old) 850 goto out; 851 852 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT); 853 if (!old_ifinfo) 854 goto out; 855 856 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD) 857 out_of_range = true; 858 batadv_neigh_ifinfo_free_ref(old_ifinfo); 859 860 out: 861 if (orig_dst_node) 862 batadv_orig_node_free_ref(orig_dst_node); 863 if (curr_gw) 864 batadv_gw_node_free_ref(curr_gw); 865 if (gw_node) 866 batadv_gw_node_free_ref(gw_node); 867 if (neigh_old) 868 batadv_neigh_node_free_ref(neigh_old); 869 if (neigh_curr) 870 batadv_neigh_node_free_ref(neigh_curr); 871 return out_of_range; 872 } 873