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