1 /* Copyright (C) 2009-2016 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/kref.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 "log.h" 46 #include "originator.h" 47 #include "packet.h" 48 #include "routing.h" 49 #include "sysfs.h" 50 #include "translation-table.h" 51 52 /* These are the offsets of the "hw type" and "hw address length" in the dhcp 53 * packet starting at the beginning of the dhcp header 54 */ 55 #define BATADV_DHCP_HTYPE_OFFSET 1 56 #define BATADV_DHCP_HLEN_OFFSET 2 57 /* Value of htype representing Ethernet */ 58 #define BATADV_DHCP_HTYPE_ETHERNET 0x01 59 /* This is the offset of the "chaddr" field in the dhcp packet starting at the 60 * beginning of the dhcp header 61 */ 62 #define BATADV_DHCP_CHADDR_OFFSET 28 63 64 /** 65 * batadv_gw_node_release - release gw_node from lists and queue for free after 66 * rcu grace period 67 * @ref: kref pointer of the gw_node 68 */ 69 static void batadv_gw_node_release(struct kref *ref) 70 { 71 struct batadv_gw_node *gw_node; 72 73 gw_node = container_of(ref, struct batadv_gw_node, refcount); 74 75 batadv_orig_node_put(gw_node->orig_node); 76 kfree_rcu(gw_node, rcu); 77 } 78 79 /** 80 * batadv_gw_node_put - decrement the gw_node refcounter and possibly release it 81 * @gw_node: gateway node to free 82 */ 83 static void batadv_gw_node_put(struct batadv_gw_node *gw_node) 84 { 85 kref_put(&gw_node->refcount, batadv_gw_node_release); 86 } 87 88 static struct batadv_gw_node * 89 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv) 90 { 91 struct batadv_gw_node *gw_node; 92 93 rcu_read_lock(); 94 gw_node = rcu_dereference(bat_priv->gw.curr_gw); 95 if (!gw_node) 96 goto out; 97 98 if (!kref_get_unless_zero(&gw_node->refcount)) 99 gw_node = NULL; 100 101 out: 102 rcu_read_unlock(); 103 return gw_node; 104 } 105 106 struct batadv_orig_node * 107 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv) 108 { 109 struct batadv_gw_node *gw_node; 110 struct batadv_orig_node *orig_node = NULL; 111 112 gw_node = batadv_gw_get_selected_gw_node(bat_priv); 113 if (!gw_node) 114 goto out; 115 116 rcu_read_lock(); 117 orig_node = gw_node->orig_node; 118 if (!orig_node) 119 goto unlock; 120 121 if (!kref_get_unless_zero(&orig_node->refcount)) 122 orig_node = NULL; 123 124 unlock: 125 rcu_read_unlock(); 126 out: 127 if (gw_node) 128 batadv_gw_node_put(gw_node); 129 return orig_node; 130 } 131 132 static void batadv_gw_select(struct batadv_priv *bat_priv, 133 struct batadv_gw_node *new_gw_node) 134 { 135 struct batadv_gw_node *curr_gw_node; 136 137 spin_lock_bh(&bat_priv->gw.list_lock); 138 139 if (new_gw_node) 140 kref_get(&new_gw_node->refcount); 141 142 curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1); 143 rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node); 144 145 if (curr_gw_node) 146 batadv_gw_node_put(curr_gw_node); 147 148 spin_unlock_bh(&bat_priv->gw.list_lock); 149 } 150 151 /** 152 * batadv_gw_reselect - force a gateway reselection 153 * @bat_priv: the bat priv with all the soft interface information 154 * 155 * Set a flag to remind the GW component to perform a new gateway reselection. 156 * However this function does not ensure that the current gateway is going to be 157 * deselected. The reselection mechanism may elect the same gateway once again. 158 * 159 * This means that invoking batadv_gw_reselect() does not guarantee a gateway 160 * change and therefore a uevent is not necessarily expected. 161 */ 162 void batadv_gw_reselect(struct batadv_priv *bat_priv) 163 { 164 atomic_set(&bat_priv->gw.reselect, 1); 165 } 166 167 static struct batadv_gw_node * 168 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv) 169 { 170 struct batadv_neigh_node *router; 171 struct batadv_neigh_ifinfo *router_ifinfo; 172 struct batadv_gw_node *gw_node, *curr_gw = NULL; 173 u64 max_gw_factor = 0; 174 u64 tmp_gw_factor = 0; 175 u8 max_tq = 0; 176 u8 tq_avg; 177 struct batadv_orig_node *orig_node; 178 179 rcu_read_lock(); 180 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 181 orig_node = gw_node->orig_node; 182 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 183 if (!router) 184 continue; 185 186 router_ifinfo = batadv_neigh_ifinfo_get(router, 187 BATADV_IF_DEFAULT); 188 if (!router_ifinfo) 189 goto next; 190 191 if (!kref_get_unless_zero(&gw_node->refcount)) 192 goto next; 193 194 tq_avg = router_ifinfo->bat_iv.tq_avg; 195 196 switch (atomic_read(&bat_priv->gw.sel_class)) { 197 case 1: /* fast connection */ 198 tmp_gw_factor = tq_avg * tq_avg; 199 tmp_gw_factor *= gw_node->bandwidth_down; 200 tmp_gw_factor *= 100 * 100; 201 tmp_gw_factor >>= 18; 202 203 if ((tmp_gw_factor > max_gw_factor) || 204 ((tmp_gw_factor == max_gw_factor) && 205 (tq_avg > max_tq))) { 206 if (curr_gw) 207 batadv_gw_node_put(curr_gw); 208 curr_gw = gw_node; 209 kref_get(&curr_gw->refcount); 210 } 211 break; 212 213 default: /* 2: stable connection (use best statistic) 214 * 3: fast-switch (use best statistic but change as 215 * soon as a better gateway appears) 216 * XX: late-switch (use best statistic but change as 217 * soon as a better gateway appears which has 218 * $routing_class more tq points) 219 */ 220 if (tq_avg > max_tq) { 221 if (curr_gw) 222 batadv_gw_node_put(curr_gw); 223 curr_gw = gw_node; 224 kref_get(&curr_gw->refcount); 225 } 226 break; 227 } 228 229 if (tq_avg > max_tq) 230 max_tq = tq_avg; 231 232 if (tmp_gw_factor > max_gw_factor) 233 max_gw_factor = tmp_gw_factor; 234 235 batadv_gw_node_put(gw_node); 236 237 next: 238 batadv_neigh_node_put(router); 239 if (router_ifinfo) 240 batadv_neigh_ifinfo_put(router_ifinfo); 241 } 242 rcu_read_unlock(); 243 244 return curr_gw; 245 } 246 247 /** 248 * batadv_gw_check_client_stop - check if client mode has been switched off 249 * @bat_priv: the bat priv with all the soft interface information 250 * 251 * This function assumes the caller has checked that the gw state *is actually 252 * changing*. This function is not supposed to be called when there is no state 253 * change. 254 */ 255 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv) 256 { 257 struct batadv_gw_node *curr_gw; 258 259 if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT) 260 return; 261 262 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 263 if (!curr_gw) 264 return; 265 266 /* deselect the current gateway so that next time that client mode is 267 * enabled a proper GW_ADD event can be sent 268 */ 269 batadv_gw_select(bat_priv, NULL); 270 271 /* if batman-adv is switching the gw client mode off and a gateway was 272 * already selected, send a DEL uevent 273 */ 274 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL); 275 276 batadv_gw_node_put(curr_gw); 277 } 278 279 void batadv_gw_election(struct batadv_priv *bat_priv) 280 { 281 struct batadv_gw_node *curr_gw = NULL; 282 struct batadv_gw_node *next_gw = NULL; 283 struct batadv_neigh_node *router = NULL; 284 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 285 char gw_addr[18] = { '\0' }; 286 287 if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT) 288 goto out; 289 290 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 291 292 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw) 293 goto out; 294 295 next_gw = batadv_gw_get_best_gw_node(bat_priv); 296 297 if (curr_gw == next_gw) 298 goto out; 299 300 if (next_gw) { 301 sprintf(gw_addr, "%pM", next_gw->orig_node->orig); 302 303 router = batadv_orig_router_get(next_gw->orig_node, 304 BATADV_IF_DEFAULT); 305 if (!router) { 306 batadv_gw_reselect(bat_priv); 307 goto out; 308 } 309 310 router_ifinfo = batadv_neigh_ifinfo_get(router, 311 BATADV_IF_DEFAULT); 312 if (!router_ifinfo) { 313 batadv_gw_reselect(bat_priv); 314 goto out; 315 } 316 } 317 318 if ((curr_gw) && (!next_gw)) { 319 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 320 "Removing selected gateway - no gateway in range\n"); 321 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, 322 NULL); 323 } else if ((!curr_gw) && (next_gw)) { 324 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 325 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 326 next_gw->orig_node->orig, 327 next_gw->bandwidth_down / 10, 328 next_gw->bandwidth_down % 10, 329 next_gw->bandwidth_up / 10, 330 next_gw->bandwidth_up % 10, 331 router_ifinfo->bat_iv.tq_avg); 332 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD, 333 gw_addr); 334 } else { 335 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 336 "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 337 next_gw->orig_node->orig, 338 next_gw->bandwidth_down / 10, 339 next_gw->bandwidth_down % 10, 340 next_gw->bandwidth_up / 10, 341 next_gw->bandwidth_up % 10, 342 router_ifinfo->bat_iv.tq_avg); 343 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE, 344 gw_addr); 345 } 346 347 batadv_gw_select(bat_priv, next_gw); 348 349 out: 350 if (curr_gw) 351 batadv_gw_node_put(curr_gw); 352 if (next_gw) 353 batadv_gw_node_put(next_gw); 354 if (router) 355 batadv_neigh_node_put(router); 356 if (router_ifinfo) 357 batadv_neigh_ifinfo_put(router_ifinfo); 358 } 359 360 void batadv_gw_check_election(struct batadv_priv *bat_priv, 361 struct batadv_orig_node *orig_node) 362 { 363 struct batadv_neigh_ifinfo *router_orig_tq = NULL; 364 struct batadv_neigh_ifinfo *router_gw_tq = NULL; 365 struct batadv_orig_node *curr_gw_orig; 366 struct batadv_neigh_node *router_gw = NULL; 367 struct batadv_neigh_node *router_orig = NULL; 368 u8 gw_tq_avg, orig_tq_avg; 369 370 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); 371 if (!curr_gw_orig) 372 goto reselect; 373 374 router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT); 375 if (!router_gw) 376 goto reselect; 377 378 router_gw_tq = batadv_neigh_ifinfo_get(router_gw, 379 BATADV_IF_DEFAULT); 380 if (!router_gw_tq) 381 goto reselect; 382 383 /* this node already is the gateway */ 384 if (curr_gw_orig == orig_node) 385 goto out; 386 387 router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 388 if (!router_orig) 389 goto out; 390 391 router_orig_tq = batadv_neigh_ifinfo_get(router_orig, 392 BATADV_IF_DEFAULT); 393 if (!router_orig_tq) 394 goto out; 395 396 gw_tq_avg = router_gw_tq->bat_iv.tq_avg; 397 orig_tq_avg = router_orig_tq->bat_iv.tq_avg; 398 399 /* the TQ value has to be better */ 400 if (orig_tq_avg < gw_tq_avg) 401 goto out; 402 403 /* if the routing class is greater than 3 the value tells us how much 404 * greater the TQ value of the new gateway must be 405 */ 406 if ((atomic_read(&bat_priv->gw.sel_class) > 3) && 407 (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw.sel_class))) 408 goto out; 409 410 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 411 "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n", 412 gw_tq_avg, orig_tq_avg); 413 414 reselect: 415 batadv_gw_reselect(bat_priv); 416 out: 417 if (curr_gw_orig) 418 batadv_orig_node_put(curr_gw_orig); 419 if (router_gw) 420 batadv_neigh_node_put(router_gw); 421 if (router_orig) 422 batadv_neigh_node_put(router_orig); 423 if (router_gw_tq) 424 batadv_neigh_ifinfo_put(router_gw_tq); 425 if (router_orig_tq) 426 batadv_neigh_ifinfo_put(router_orig_tq); 427 } 428 429 /** 430 * batadv_gw_node_add - add gateway node to list of available gateways 431 * @bat_priv: the bat priv with all the soft interface information 432 * @orig_node: originator announcing gateway capabilities 433 * @gateway: announced bandwidth information 434 */ 435 static void batadv_gw_node_add(struct batadv_priv *bat_priv, 436 struct batadv_orig_node *orig_node, 437 struct batadv_tvlv_gateway_data *gateway) 438 { 439 struct batadv_gw_node *gw_node; 440 441 if (gateway->bandwidth_down == 0) 442 return; 443 444 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); 445 if (!gw_node) 446 return; 447 448 kref_get(&orig_node->refcount); 449 INIT_HLIST_NODE(&gw_node->list); 450 gw_node->orig_node = orig_node; 451 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 452 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 453 kref_init(&gw_node->refcount); 454 455 spin_lock_bh(&bat_priv->gw.list_lock); 456 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list); 457 spin_unlock_bh(&bat_priv->gw.list_lock); 458 459 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 460 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", 461 orig_node->orig, 462 ntohl(gateway->bandwidth_down) / 10, 463 ntohl(gateway->bandwidth_down) % 10, 464 ntohl(gateway->bandwidth_up) / 10, 465 ntohl(gateway->bandwidth_up) % 10); 466 } 467 468 /** 469 * batadv_gw_node_get - retrieve gateway node from list of available gateways 470 * @bat_priv: the bat priv with all the soft interface information 471 * @orig_node: originator announcing gateway capabilities 472 * 473 * Return: gateway node if found or NULL otherwise. 474 */ 475 static struct batadv_gw_node * 476 batadv_gw_node_get(struct batadv_priv *bat_priv, 477 struct batadv_orig_node *orig_node) 478 { 479 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL; 480 481 rcu_read_lock(); 482 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) { 483 if (gw_node_tmp->orig_node != orig_node) 484 continue; 485 486 if (!kref_get_unless_zero(&gw_node_tmp->refcount)) 487 continue; 488 489 gw_node = gw_node_tmp; 490 break; 491 } 492 rcu_read_unlock(); 493 494 return gw_node; 495 } 496 497 /** 498 * batadv_gw_node_update - update list of available gateways with changed 499 * bandwidth information 500 * @bat_priv: the bat priv with all the soft interface information 501 * @orig_node: originator announcing gateway capabilities 502 * @gateway: announced bandwidth information 503 */ 504 void batadv_gw_node_update(struct batadv_priv *bat_priv, 505 struct batadv_orig_node *orig_node, 506 struct batadv_tvlv_gateway_data *gateway) 507 { 508 struct batadv_gw_node *gw_node, *curr_gw = NULL; 509 510 gw_node = batadv_gw_node_get(bat_priv, orig_node); 511 if (!gw_node) { 512 batadv_gw_node_add(bat_priv, orig_node, gateway); 513 goto out; 514 } 515 516 if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) && 517 (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))) 518 goto out; 519 520 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 521 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n", 522 orig_node->orig, 523 gw_node->bandwidth_down / 10, 524 gw_node->bandwidth_down % 10, 525 gw_node->bandwidth_up / 10, 526 gw_node->bandwidth_up % 10, 527 ntohl(gateway->bandwidth_down) / 10, 528 ntohl(gateway->bandwidth_down) % 10, 529 ntohl(gateway->bandwidth_up) / 10, 530 ntohl(gateway->bandwidth_up) % 10); 531 532 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 533 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 534 535 if (ntohl(gateway->bandwidth_down) == 0) { 536 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 537 "Gateway %pM removed from gateway list\n", 538 orig_node->orig); 539 540 /* Note: We don't need a NULL check here, since curr_gw never 541 * gets dereferenced. 542 */ 543 spin_lock_bh(&bat_priv->gw.list_lock); 544 if (!hlist_unhashed(&gw_node->list)) { 545 hlist_del_init_rcu(&gw_node->list); 546 batadv_gw_node_put(gw_node); 547 } 548 spin_unlock_bh(&bat_priv->gw.list_lock); 549 550 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 551 if (gw_node == curr_gw) 552 batadv_gw_reselect(bat_priv); 553 554 if (curr_gw) 555 batadv_gw_node_put(curr_gw); 556 } 557 558 out: 559 if (gw_node) 560 batadv_gw_node_put(gw_node); 561 } 562 563 void batadv_gw_node_delete(struct batadv_priv *bat_priv, 564 struct batadv_orig_node *orig_node) 565 { 566 struct batadv_tvlv_gateway_data gateway; 567 568 gateway.bandwidth_down = 0; 569 gateway.bandwidth_up = 0; 570 571 batadv_gw_node_update(bat_priv, orig_node, &gateway); 572 } 573 574 void batadv_gw_node_free(struct batadv_priv *bat_priv) 575 { 576 struct batadv_gw_node *gw_node; 577 struct hlist_node *node_tmp; 578 579 spin_lock_bh(&bat_priv->gw.list_lock); 580 hlist_for_each_entry_safe(gw_node, node_tmp, 581 &bat_priv->gw.list, list) { 582 hlist_del_init_rcu(&gw_node->list); 583 batadv_gw_node_put(gw_node); 584 } 585 spin_unlock_bh(&bat_priv->gw.list_lock); 586 } 587 588 /* fails if orig_node has no router */ 589 static int batadv_write_buffer_text(struct batadv_priv *bat_priv, 590 struct seq_file *seq, 591 const struct batadv_gw_node *gw_node) 592 { 593 struct batadv_gw_node *curr_gw; 594 struct batadv_neigh_node *router; 595 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 596 int ret = -1; 597 598 router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT); 599 if (!router) 600 goto out; 601 602 router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT); 603 if (!router_ifinfo) 604 goto out; 605 606 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 607 608 seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n", 609 (curr_gw == gw_node ? "=>" : " "), 610 gw_node->orig_node->orig, 611 router_ifinfo->bat_iv.tq_avg, router->addr, 612 router->if_incoming->net_dev->name, 613 gw_node->bandwidth_down / 10, 614 gw_node->bandwidth_down % 10, 615 gw_node->bandwidth_up / 10, 616 gw_node->bandwidth_up % 10); 617 ret = seq_has_overflowed(seq) ? -1 : 0; 618 619 if (curr_gw) 620 batadv_gw_node_put(curr_gw); 621 out: 622 if (router_ifinfo) 623 batadv_neigh_ifinfo_put(router_ifinfo); 624 if (router) 625 batadv_neigh_node_put(router); 626 return ret; 627 } 628 629 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset) 630 { 631 struct net_device *net_dev = (struct net_device *)seq->private; 632 struct batadv_priv *bat_priv = netdev_priv(net_dev); 633 struct batadv_hard_iface *primary_if; 634 struct batadv_gw_node *gw_node; 635 int gw_count = 0; 636 637 primary_if = batadv_seq_print_text_primary_if_get(seq); 638 if (!primary_if) 639 goto out; 640 641 seq_printf(seq, 642 " Gateway (#/255) Nexthop [outgoingIF]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n", 643 BATADV_SOURCE_VERSION, primary_if->net_dev->name, 644 primary_if->net_dev->dev_addr, net_dev->name); 645 646 rcu_read_lock(); 647 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 648 /* fails if orig_node has no router */ 649 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0) 650 continue; 651 652 gw_count++; 653 } 654 rcu_read_unlock(); 655 656 if (gw_count == 0) 657 seq_puts(seq, "No gateways in range ...\n"); 658 659 out: 660 if (primary_if) 661 batadv_hardif_put(primary_if); 662 return 0; 663 } 664 665 /** 666 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message 667 * @skb: the packet to check 668 * @header_len: a pointer to the batman-adv header size 669 * @chaddr: buffer where the client address will be stored. Valid 670 * only if the function returns BATADV_DHCP_TO_CLIENT 671 * 672 * This function may re-allocate the data buffer of the skb passed as argument. 673 * 674 * Return: 675 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error 676 * while parsing it 677 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server 678 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client 679 */ 680 enum batadv_dhcp_recipient 681 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, 682 u8 *chaddr) 683 { 684 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO; 685 struct ethhdr *ethhdr; 686 struct iphdr *iphdr; 687 struct ipv6hdr *ipv6hdr; 688 struct udphdr *udphdr; 689 struct vlan_ethhdr *vhdr; 690 int chaddr_offset; 691 __be16 proto; 692 u8 *p; 693 694 /* check for ethernet header */ 695 if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) 696 return BATADV_DHCP_NO; 697 698 ethhdr = eth_hdr(skb); 699 proto = ethhdr->h_proto; 700 *header_len += ETH_HLEN; 701 702 /* check for initial vlan header */ 703 if (proto == htons(ETH_P_8021Q)) { 704 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) 705 return BATADV_DHCP_NO; 706 707 vhdr = vlan_eth_hdr(skb); 708 proto = vhdr->h_vlan_encapsulated_proto; 709 *header_len += VLAN_HLEN; 710 } 711 712 /* check for ip header */ 713 switch (proto) { 714 case htons(ETH_P_IP): 715 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) 716 return BATADV_DHCP_NO; 717 718 iphdr = (struct iphdr *)(skb->data + *header_len); 719 *header_len += iphdr->ihl * 4; 720 721 /* check for udp header */ 722 if (iphdr->protocol != IPPROTO_UDP) 723 return BATADV_DHCP_NO; 724 725 break; 726 case htons(ETH_P_IPV6): 727 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) 728 return BATADV_DHCP_NO; 729 730 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); 731 *header_len += sizeof(*ipv6hdr); 732 733 /* check for udp header */ 734 if (ipv6hdr->nexthdr != IPPROTO_UDP) 735 return BATADV_DHCP_NO; 736 737 break; 738 default: 739 return BATADV_DHCP_NO; 740 } 741 742 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) 743 return BATADV_DHCP_NO; 744 745 udphdr = (struct udphdr *)(skb->data + *header_len); 746 *header_len += sizeof(*udphdr); 747 748 /* check for bootp port */ 749 switch (proto) { 750 case htons(ETH_P_IP): 751 if (udphdr->dest == htons(67)) 752 ret = BATADV_DHCP_TO_SERVER; 753 else if (udphdr->source == htons(67)) 754 ret = BATADV_DHCP_TO_CLIENT; 755 break; 756 case htons(ETH_P_IPV6): 757 if (udphdr->dest == htons(547)) 758 ret = BATADV_DHCP_TO_SERVER; 759 else if (udphdr->source == htons(547)) 760 ret = BATADV_DHCP_TO_CLIENT; 761 break; 762 } 763 764 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; 765 /* store the client address if the message is going to a client */ 766 if (ret == BATADV_DHCP_TO_CLIENT && 767 pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { 768 /* check if the DHCP packet carries an Ethernet DHCP */ 769 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; 770 if (*p != BATADV_DHCP_HTYPE_ETHERNET) 771 return BATADV_DHCP_NO; 772 773 /* check if the DHCP packet carries a valid Ethernet address */ 774 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET; 775 if (*p != ETH_ALEN) 776 return BATADV_DHCP_NO; 777 778 ether_addr_copy(chaddr, skb->data + chaddr_offset); 779 } 780 781 return ret; 782 } 783 784 /** 785 * batadv_gw_out_of_range - check if the dhcp request destination is the best gw 786 * @bat_priv: the bat priv with all the soft interface information 787 * @skb: the outgoing packet 788 * 789 * Check if the skb is a DHCP request and if it is sent to the current best GW 790 * server. Due to topology changes it may be the case that the GW server 791 * previously selected is not the best one anymore. 792 * 793 * This call might reallocate skb data. 794 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER. 795 * 796 * Return: true if the packet destination is unicast and it is not the best gw, 797 * false otherwise. 798 */ 799 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, 800 struct sk_buff *skb) 801 { 802 struct batadv_neigh_node *neigh_curr = NULL; 803 struct batadv_neigh_node *neigh_old = NULL; 804 struct batadv_orig_node *orig_dst_node = NULL; 805 struct batadv_gw_node *gw_node = NULL; 806 struct batadv_gw_node *curr_gw = NULL; 807 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; 808 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 809 bool out_of_range = false; 810 u8 curr_tq_avg; 811 unsigned short vid; 812 813 vid = batadv_get_vid(skb, 0); 814 815 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 816 ethhdr->h_dest, vid); 817 if (!orig_dst_node) 818 goto out; 819 820 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node); 821 if (!gw_node) 822 goto out; 823 824 switch (atomic_read(&bat_priv->gw.mode)) { 825 case BATADV_GW_MODE_SERVER: 826 /* If we are a GW then we are our best GW. We can artificially 827 * set the tq towards ourself as the maximum value 828 */ 829 curr_tq_avg = BATADV_TQ_MAX_VALUE; 830 break; 831 case BATADV_GW_MODE_CLIENT: 832 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 833 if (!curr_gw) 834 goto out; 835 836 /* packet is going to our gateway */ 837 if (curr_gw->orig_node == orig_dst_node) 838 goto out; 839 840 /* If the dhcp packet has been sent to a different gw, 841 * we have to evaluate whether the old gw is still 842 * reliable enough 843 */ 844 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node, 845 NULL); 846 if (!neigh_curr) 847 goto out; 848 849 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr, 850 BATADV_IF_DEFAULT); 851 if (!curr_ifinfo) 852 goto out; 853 854 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg; 855 batadv_neigh_ifinfo_put(curr_ifinfo); 856 857 break; 858 case BATADV_GW_MODE_OFF: 859 default: 860 goto out; 861 } 862 863 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL); 864 if (!neigh_old) 865 goto out; 866 867 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT); 868 if (!old_ifinfo) 869 goto out; 870 871 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD) 872 out_of_range = true; 873 batadv_neigh_ifinfo_put(old_ifinfo); 874 875 out: 876 if (orig_dst_node) 877 batadv_orig_node_put(orig_dst_node); 878 if (curr_gw) 879 batadv_gw_node_put(curr_gw); 880 if (gw_node) 881 batadv_gw_node_put(gw_node); 882 if (neigh_old) 883 batadv_neigh_node_put(neigh_old); 884 if (neigh_curr) 885 batadv_neigh_node_put(neigh_curr); 886 return out_of_range; 887 } 888