1 /* Copyright (C) 2009-2015 B.A.T.M.A.N. contributors: 2 * 3 * Marek Lindner 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of version 2 of the GNU General Public 7 * License as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, see <http://www.gnu.org/licenses/>. 16 */ 17 18 #include "gateway_client.h" 19 #include "main.h" 20 21 #include <linux/atomic.h> 22 #include <linux/byteorder/generic.h> 23 #include <linux/etherdevice.h> 24 #include <linux/fs.h> 25 #include <linux/if_ether.h> 26 #include <linux/if_vlan.h> 27 #include <linux/in.h> 28 #include <linux/ip.h> 29 #include <linux/ipv6.h> 30 #include <linux/kernel.h> 31 #include <linux/list.h> 32 #include <linux/netdevice.h> 33 #include <linux/rculist.h> 34 #include <linux/rcupdate.h> 35 #include <linux/seq_file.h> 36 #include <linux/skbuff.h> 37 #include <linux/slab.h> 38 #include <linux/spinlock.h> 39 #include <linux/stddef.h> 40 #include <linux/udp.h> 41 42 #include "gateway_common.h" 43 #include "hard-interface.h" 44 #include "originator.h" 45 #include "packet.h" 46 #include "routing.h" 47 #include "sysfs.h" 48 #include "translation-table.h" 49 50 /* These are the offsets of the "hw type" and "hw address length" in the dhcp 51 * packet starting at the beginning of the dhcp header 52 */ 53 #define BATADV_DHCP_HTYPE_OFFSET 1 54 #define BATADV_DHCP_HLEN_OFFSET 2 55 /* Value of htype representing Ethernet */ 56 #define BATADV_DHCP_HTYPE_ETHERNET 0x01 57 /* This is the offset of the "chaddr" field in the dhcp packet starting at the 58 * beginning of the dhcp header 59 */ 60 #define BATADV_DHCP_CHADDR_OFFSET 28 61 62 static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node) 63 { 64 if (atomic_dec_and_test(&gw_node->refcount)) { 65 batadv_orig_node_free_ref(gw_node->orig_node); 66 kfree_rcu(gw_node, rcu); 67 } 68 } 69 70 static struct batadv_gw_node * 71 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv) 72 { 73 struct batadv_gw_node *gw_node; 74 75 rcu_read_lock(); 76 gw_node = rcu_dereference(bat_priv->gw.curr_gw); 77 if (!gw_node) 78 goto out; 79 80 if (!atomic_inc_not_zero(&gw_node->refcount)) 81 gw_node = NULL; 82 83 out: 84 rcu_read_unlock(); 85 return gw_node; 86 } 87 88 struct batadv_orig_node * 89 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv) 90 { 91 struct batadv_gw_node *gw_node; 92 struct batadv_orig_node *orig_node = NULL; 93 94 gw_node = batadv_gw_get_selected_gw_node(bat_priv); 95 if (!gw_node) 96 goto out; 97 98 rcu_read_lock(); 99 orig_node = gw_node->orig_node; 100 if (!orig_node) 101 goto unlock; 102 103 if (!atomic_inc_not_zero(&orig_node->refcount)) 104 orig_node = NULL; 105 106 unlock: 107 rcu_read_unlock(); 108 out: 109 if (gw_node) 110 batadv_gw_node_free_ref(gw_node); 111 return orig_node; 112 } 113 114 static void batadv_gw_select(struct batadv_priv *bat_priv, 115 struct batadv_gw_node *new_gw_node) 116 { 117 struct batadv_gw_node *curr_gw_node; 118 119 spin_lock_bh(&bat_priv->gw.list_lock); 120 121 if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount)) 122 new_gw_node = NULL; 123 124 curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1); 125 rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node); 126 127 if (curr_gw_node) 128 batadv_gw_node_free_ref(curr_gw_node); 129 130 spin_unlock_bh(&bat_priv->gw.list_lock); 131 } 132 133 /** 134 * batadv_gw_reselect - force a gateway reselection 135 * @bat_priv: the bat priv with all the soft interface information 136 * 137 * Set a flag to remind the GW component to perform a new gateway reselection. 138 * However this function does not ensure that the current gateway is going to be 139 * deselected. The reselection mechanism may elect the same gateway once again. 140 * 141 * This means that invoking batadv_gw_reselect() does not guarantee a gateway 142 * change and therefore a uevent is not necessarily expected. 143 */ 144 void batadv_gw_reselect(struct batadv_priv *bat_priv) 145 { 146 atomic_set(&bat_priv->gw.reselect, 1); 147 } 148 149 static struct batadv_gw_node * 150 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv) 151 { 152 struct batadv_neigh_node *router; 153 struct batadv_neigh_ifinfo *router_ifinfo; 154 struct batadv_gw_node *gw_node, *curr_gw = NULL; 155 u64 max_gw_factor = 0; 156 u64 tmp_gw_factor = 0; 157 u8 max_tq = 0; 158 u8 tq_avg; 159 struct batadv_orig_node *orig_node; 160 161 rcu_read_lock(); 162 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 163 orig_node = gw_node->orig_node; 164 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 165 if (!router) 166 continue; 167 168 router_ifinfo = batadv_neigh_ifinfo_get(router, 169 BATADV_IF_DEFAULT); 170 if (!router_ifinfo) 171 goto next; 172 173 if (!atomic_inc_not_zero(&gw_node->refcount)) 174 goto next; 175 176 tq_avg = router_ifinfo->bat_iv.tq_avg; 177 178 switch (atomic_read(&bat_priv->gw_sel_class)) { 179 case 1: /* fast connection */ 180 tmp_gw_factor = tq_avg * tq_avg; 181 tmp_gw_factor *= gw_node->bandwidth_down; 182 tmp_gw_factor *= 100 * 100; 183 tmp_gw_factor >>= 18; 184 185 if ((tmp_gw_factor > max_gw_factor) || 186 ((tmp_gw_factor == max_gw_factor) && 187 (tq_avg > max_tq))) { 188 if (curr_gw) 189 batadv_gw_node_free_ref(curr_gw); 190 curr_gw = gw_node; 191 atomic_inc(&curr_gw->refcount); 192 } 193 break; 194 195 default: /* 2: stable connection (use best statistic) 196 * 3: fast-switch (use best statistic but change as 197 * soon as a better gateway appears) 198 * XX: late-switch (use best statistic but change as 199 * soon as a better gateway appears which has 200 * $routing_class more tq points) 201 */ 202 if (tq_avg > max_tq) { 203 if (curr_gw) 204 batadv_gw_node_free_ref(curr_gw); 205 curr_gw = gw_node; 206 atomic_inc(&curr_gw->refcount); 207 } 208 break; 209 } 210 211 if (tq_avg > max_tq) 212 max_tq = tq_avg; 213 214 if (tmp_gw_factor > max_gw_factor) 215 max_gw_factor = tmp_gw_factor; 216 217 batadv_gw_node_free_ref(gw_node); 218 219 next: 220 batadv_neigh_node_free_ref(router); 221 if (router_ifinfo) 222 batadv_neigh_ifinfo_free_ref(router_ifinfo); 223 } 224 rcu_read_unlock(); 225 226 return curr_gw; 227 } 228 229 /** 230 * batadv_gw_check_client_stop - check if client mode has been switched off 231 * @bat_priv: the bat priv with all the soft interface information 232 * 233 * This function assumes the caller has checked that the gw state *is actually 234 * changing*. This function is not supposed to be called when there is no state 235 * change. 236 */ 237 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv) 238 { 239 struct batadv_gw_node *curr_gw; 240 241 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT) 242 return; 243 244 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 245 if (!curr_gw) 246 return; 247 248 /* deselect the current gateway so that next time that client mode is 249 * enabled a proper GW_ADD event can be sent 250 */ 251 batadv_gw_select(bat_priv, NULL); 252 253 /* if batman-adv is switching the gw client mode off and a gateway was 254 * already selected, send a DEL uevent 255 */ 256 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL); 257 258 batadv_gw_node_free_ref(curr_gw); 259 } 260 261 void batadv_gw_election(struct batadv_priv *bat_priv) 262 { 263 struct batadv_gw_node *curr_gw = NULL; 264 struct batadv_gw_node *next_gw = NULL; 265 struct batadv_neigh_node *router = NULL; 266 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 267 char gw_addr[18] = { '\0' }; 268 269 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT) 270 goto out; 271 272 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 273 274 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw) 275 goto out; 276 277 next_gw = batadv_gw_get_best_gw_node(bat_priv); 278 279 if (curr_gw == next_gw) 280 goto out; 281 282 if (next_gw) { 283 sprintf(gw_addr, "%pM", next_gw->orig_node->orig); 284 285 router = batadv_orig_router_get(next_gw->orig_node, 286 BATADV_IF_DEFAULT); 287 if (!router) { 288 batadv_gw_reselect(bat_priv); 289 goto out; 290 } 291 292 router_ifinfo = batadv_neigh_ifinfo_get(router, 293 BATADV_IF_DEFAULT); 294 if (!router_ifinfo) { 295 batadv_gw_reselect(bat_priv); 296 goto out; 297 } 298 } 299 300 if ((curr_gw) && (!next_gw)) { 301 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 302 "Removing selected gateway - no gateway in range\n"); 303 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, 304 NULL); 305 } else if ((!curr_gw) && (next_gw)) { 306 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 307 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 308 next_gw->orig_node->orig, 309 next_gw->bandwidth_down / 10, 310 next_gw->bandwidth_down % 10, 311 next_gw->bandwidth_up / 10, 312 next_gw->bandwidth_up % 10, 313 router_ifinfo->bat_iv.tq_avg); 314 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD, 315 gw_addr); 316 } else { 317 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 318 "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 319 next_gw->orig_node->orig, 320 next_gw->bandwidth_down / 10, 321 next_gw->bandwidth_down % 10, 322 next_gw->bandwidth_up / 10, 323 next_gw->bandwidth_up % 10, 324 router_ifinfo->bat_iv.tq_avg); 325 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE, 326 gw_addr); 327 } 328 329 batadv_gw_select(bat_priv, next_gw); 330 331 out: 332 if (curr_gw) 333 batadv_gw_node_free_ref(curr_gw); 334 if (next_gw) 335 batadv_gw_node_free_ref(next_gw); 336 if (router) 337 batadv_neigh_node_free_ref(router); 338 if (router_ifinfo) 339 batadv_neigh_ifinfo_free_ref(router_ifinfo); 340 } 341 342 void batadv_gw_check_election(struct batadv_priv *bat_priv, 343 struct batadv_orig_node *orig_node) 344 { 345 struct batadv_neigh_ifinfo *router_orig_tq = NULL; 346 struct batadv_neigh_ifinfo *router_gw_tq = NULL; 347 struct batadv_orig_node *curr_gw_orig; 348 struct batadv_neigh_node *router_gw = NULL; 349 struct batadv_neigh_node *router_orig = NULL; 350 u8 gw_tq_avg, orig_tq_avg; 351 352 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); 353 if (!curr_gw_orig) 354 goto reselect; 355 356 router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT); 357 if (!router_gw) 358 goto reselect; 359 360 router_gw_tq = batadv_neigh_ifinfo_get(router_gw, 361 BATADV_IF_DEFAULT); 362 if (!router_gw_tq) 363 goto reselect; 364 365 /* this node already is the gateway */ 366 if (curr_gw_orig == orig_node) 367 goto out; 368 369 router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 370 if (!router_orig) 371 goto out; 372 373 router_orig_tq = batadv_neigh_ifinfo_get(router_orig, 374 BATADV_IF_DEFAULT); 375 if (!router_orig_tq) 376 goto out; 377 378 gw_tq_avg = router_gw_tq->bat_iv.tq_avg; 379 orig_tq_avg = router_orig_tq->bat_iv.tq_avg; 380 381 /* the TQ value has to be better */ 382 if (orig_tq_avg < gw_tq_avg) 383 goto out; 384 385 /* if the routing class is greater than 3 the value tells us how much 386 * greater the TQ value of the new gateway must be 387 */ 388 if ((atomic_read(&bat_priv->gw_sel_class) > 3) && 389 (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class))) 390 goto out; 391 392 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 393 "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n", 394 gw_tq_avg, orig_tq_avg); 395 396 reselect: 397 batadv_gw_reselect(bat_priv); 398 out: 399 if (curr_gw_orig) 400 batadv_orig_node_free_ref(curr_gw_orig); 401 if (router_gw) 402 batadv_neigh_node_free_ref(router_gw); 403 if (router_orig) 404 batadv_neigh_node_free_ref(router_orig); 405 if (router_gw_tq) 406 batadv_neigh_ifinfo_free_ref(router_gw_tq); 407 if (router_orig_tq) 408 batadv_neigh_ifinfo_free_ref(router_orig_tq); 409 } 410 411 /** 412 * batadv_gw_node_add - add gateway node to list of available gateways 413 * @bat_priv: the bat priv with all the soft interface information 414 * @orig_node: originator announcing gateway capabilities 415 * @gateway: announced bandwidth information 416 */ 417 static void batadv_gw_node_add(struct batadv_priv *bat_priv, 418 struct batadv_orig_node *orig_node, 419 struct batadv_tvlv_gateway_data *gateway) 420 { 421 struct batadv_gw_node *gw_node; 422 423 if (gateway->bandwidth_down == 0) 424 return; 425 426 if (!atomic_inc_not_zero(&orig_node->refcount)) 427 return; 428 429 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); 430 if (!gw_node) { 431 batadv_orig_node_free_ref(orig_node); 432 return; 433 } 434 435 INIT_HLIST_NODE(&gw_node->list); 436 gw_node->orig_node = orig_node; 437 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 438 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 439 atomic_set(&gw_node->refcount, 1); 440 441 spin_lock_bh(&bat_priv->gw.list_lock); 442 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list); 443 spin_unlock_bh(&bat_priv->gw.list_lock); 444 445 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 446 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", 447 orig_node->orig, 448 ntohl(gateway->bandwidth_down) / 10, 449 ntohl(gateway->bandwidth_down) % 10, 450 ntohl(gateway->bandwidth_up) / 10, 451 ntohl(gateway->bandwidth_up) % 10); 452 } 453 454 /** 455 * batadv_gw_node_get - retrieve gateway node from list of available gateways 456 * @bat_priv: the bat priv with all the soft interface information 457 * @orig_node: originator announcing gateway capabilities 458 * 459 * Returns gateway node if found or NULL otherwise. 460 */ 461 static struct batadv_gw_node * 462 batadv_gw_node_get(struct batadv_priv *bat_priv, 463 struct batadv_orig_node *orig_node) 464 { 465 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL; 466 467 rcu_read_lock(); 468 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) { 469 if (gw_node_tmp->orig_node != orig_node) 470 continue; 471 472 if (!atomic_inc_not_zero(&gw_node_tmp->refcount)) 473 continue; 474 475 gw_node = gw_node_tmp; 476 break; 477 } 478 rcu_read_unlock(); 479 480 return gw_node; 481 } 482 483 /** 484 * batadv_gw_node_update - update list of available gateways with changed 485 * bandwidth information 486 * @bat_priv: the bat priv with all the soft interface information 487 * @orig_node: originator announcing gateway capabilities 488 * @gateway: announced bandwidth information 489 */ 490 void batadv_gw_node_update(struct batadv_priv *bat_priv, 491 struct batadv_orig_node *orig_node, 492 struct batadv_tvlv_gateway_data *gateway) 493 { 494 struct batadv_gw_node *gw_node, *curr_gw = NULL; 495 496 gw_node = batadv_gw_node_get(bat_priv, orig_node); 497 if (!gw_node) { 498 batadv_gw_node_add(bat_priv, orig_node, gateway); 499 goto out; 500 } 501 502 if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) && 503 (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))) 504 goto out; 505 506 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 507 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n", 508 orig_node->orig, 509 gw_node->bandwidth_down / 10, 510 gw_node->bandwidth_down % 10, 511 gw_node->bandwidth_up / 10, 512 gw_node->bandwidth_up % 10, 513 ntohl(gateway->bandwidth_down) / 10, 514 ntohl(gateway->bandwidth_down) % 10, 515 ntohl(gateway->bandwidth_up) / 10, 516 ntohl(gateway->bandwidth_up) % 10); 517 518 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 519 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 520 521 if (ntohl(gateway->bandwidth_down) == 0) { 522 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 523 "Gateway %pM removed from gateway list\n", 524 orig_node->orig); 525 526 /* Note: We don't need a NULL check here, since curr_gw never 527 * gets dereferenced. 528 */ 529 spin_lock_bh(&bat_priv->gw.list_lock); 530 hlist_del_init_rcu(&gw_node->list); 531 spin_unlock_bh(&bat_priv->gw.list_lock); 532 533 batadv_gw_node_free_ref(gw_node); 534 535 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 536 if (gw_node == curr_gw) 537 batadv_gw_reselect(bat_priv); 538 539 if (curr_gw) 540 batadv_gw_node_free_ref(curr_gw); 541 } 542 543 out: 544 if (gw_node) 545 batadv_gw_node_free_ref(gw_node); 546 } 547 548 void batadv_gw_node_delete(struct batadv_priv *bat_priv, 549 struct batadv_orig_node *orig_node) 550 { 551 struct batadv_tvlv_gateway_data gateway; 552 553 gateway.bandwidth_down = 0; 554 gateway.bandwidth_up = 0; 555 556 batadv_gw_node_update(bat_priv, orig_node, &gateway); 557 } 558 559 void batadv_gw_node_free(struct batadv_priv *bat_priv) 560 { 561 struct batadv_gw_node *gw_node; 562 struct hlist_node *node_tmp; 563 564 spin_lock_bh(&bat_priv->gw.list_lock); 565 hlist_for_each_entry_safe(gw_node, node_tmp, 566 &bat_priv->gw.list, list) { 567 hlist_del_init_rcu(&gw_node->list); 568 batadv_gw_node_free_ref(gw_node); 569 } 570 spin_unlock_bh(&bat_priv->gw.list_lock); 571 } 572 573 /* fails if orig_node has no router */ 574 static int batadv_write_buffer_text(struct batadv_priv *bat_priv, 575 struct seq_file *seq, 576 const struct batadv_gw_node *gw_node) 577 { 578 struct batadv_gw_node *curr_gw; 579 struct batadv_neigh_node *router; 580 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 581 int ret = -1; 582 583 router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT); 584 if (!router) 585 goto out; 586 587 router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT); 588 if (!router_ifinfo) 589 goto out; 590 591 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 592 593 seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n", 594 (curr_gw == gw_node ? "=>" : " "), 595 gw_node->orig_node->orig, 596 router_ifinfo->bat_iv.tq_avg, router->addr, 597 router->if_incoming->net_dev->name, 598 gw_node->bandwidth_down / 10, 599 gw_node->bandwidth_down % 10, 600 gw_node->bandwidth_up / 10, 601 gw_node->bandwidth_up % 10); 602 ret = seq_has_overflowed(seq) ? -1 : 0; 603 604 if (curr_gw) 605 batadv_gw_node_free_ref(curr_gw); 606 out: 607 if (router_ifinfo) 608 batadv_neigh_ifinfo_free_ref(router_ifinfo); 609 if (router) 610 batadv_neigh_node_free_ref(router); 611 return ret; 612 } 613 614 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset) 615 { 616 struct net_device *net_dev = (struct net_device *)seq->private; 617 struct batadv_priv *bat_priv = netdev_priv(net_dev); 618 struct batadv_hard_iface *primary_if; 619 struct batadv_gw_node *gw_node; 620 int gw_count = 0; 621 622 primary_if = batadv_seq_print_text_primary_if_get(seq); 623 if (!primary_if) 624 goto out; 625 626 seq_printf(seq, 627 " %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n", 628 "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF", 629 BATADV_SOURCE_VERSION, primary_if->net_dev->name, 630 primary_if->net_dev->dev_addr, net_dev->name); 631 632 rcu_read_lock(); 633 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 634 /* fails if orig_node has no router */ 635 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0) 636 continue; 637 638 gw_count++; 639 } 640 rcu_read_unlock(); 641 642 if (gw_count == 0) 643 seq_puts(seq, "No gateways in range ...\n"); 644 645 out: 646 if (primary_if) 647 batadv_hardif_free_ref(primary_if); 648 return 0; 649 } 650 651 /** 652 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message 653 * @skb: the packet to check 654 * @header_len: a pointer to the batman-adv header size 655 * @chaddr: buffer where the client address will be stored. Valid 656 * only if the function returns BATADV_DHCP_TO_CLIENT 657 * 658 * Returns: 659 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error 660 * while parsing it 661 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server 662 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client 663 * 664 * This function may re-allocate the data buffer of the skb passed as argument. 665 */ 666 enum batadv_dhcp_recipient 667 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, 668 u8 *chaddr) 669 { 670 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO; 671 struct ethhdr *ethhdr; 672 struct iphdr *iphdr; 673 struct ipv6hdr *ipv6hdr; 674 struct udphdr *udphdr; 675 struct vlan_ethhdr *vhdr; 676 int chaddr_offset; 677 __be16 proto; 678 u8 *p; 679 680 /* check for ethernet header */ 681 if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) 682 return BATADV_DHCP_NO; 683 684 ethhdr = eth_hdr(skb); 685 proto = ethhdr->h_proto; 686 *header_len += ETH_HLEN; 687 688 /* check for initial vlan header */ 689 if (proto == htons(ETH_P_8021Q)) { 690 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) 691 return BATADV_DHCP_NO; 692 693 vhdr = vlan_eth_hdr(skb); 694 proto = vhdr->h_vlan_encapsulated_proto; 695 *header_len += VLAN_HLEN; 696 } 697 698 /* check for ip header */ 699 switch (proto) { 700 case htons(ETH_P_IP): 701 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) 702 return BATADV_DHCP_NO; 703 704 iphdr = (struct iphdr *)(skb->data + *header_len); 705 *header_len += iphdr->ihl * 4; 706 707 /* check for udp header */ 708 if (iphdr->protocol != IPPROTO_UDP) 709 return BATADV_DHCP_NO; 710 711 break; 712 case htons(ETH_P_IPV6): 713 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) 714 return BATADV_DHCP_NO; 715 716 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); 717 *header_len += sizeof(*ipv6hdr); 718 719 /* check for udp header */ 720 if (ipv6hdr->nexthdr != IPPROTO_UDP) 721 return BATADV_DHCP_NO; 722 723 break; 724 default: 725 return BATADV_DHCP_NO; 726 } 727 728 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) 729 return BATADV_DHCP_NO; 730 731 udphdr = (struct udphdr *)(skb->data + *header_len); 732 *header_len += sizeof(*udphdr); 733 734 /* check for bootp port */ 735 switch (proto) { 736 case htons(ETH_P_IP): 737 if (udphdr->dest == htons(67)) 738 ret = BATADV_DHCP_TO_SERVER; 739 else if (udphdr->source == htons(67)) 740 ret = BATADV_DHCP_TO_CLIENT; 741 break; 742 case htons(ETH_P_IPV6): 743 if (udphdr->dest == htons(547)) 744 ret = BATADV_DHCP_TO_SERVER; 745 else if (udphdr->source == htons(547)) 746 ret = BATADV_DHCP_TO_CLIENT; 747 break; 748 } 749 750 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; 751 /* store the client address if the message is going to a client */ 752 if (ret == BATADV_DHCP_TO_CLIENT && 753 pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { 754 /* check if the DHCP packet carries an Ethernet DHCP */ 755 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; 756 if (*p != BATADV_DHCP_HTYPE_ETHERNET) 757 return BATADV_DHCP_NO; 758 759 /* check if the DHCP packet carries a valid Ethernet address */ 760 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET; 761 if (*p != ETH_ALEN) 762 return BATADV_DHCP_NO; 763 764 ether_addr_copy(chaddr, skb->data + chaddr_offset); 765 } 766 767 return ret; 768 } 769 770 /** 771 * batadv_gw_out_of_range - check if the dhcp request destination is the best gw 772 * @bat_priv: the bat priv with all the soft interface information 773 * @skb: the outgoing packet 774 * 775 * Check if the skb is a DHCP request and if it is sent to the current best GW 776 * server. Due to topology changes it may be the case that the GW server 777 * previously selected is not the best one anymore. 778 * 779 * Returns true if the packet destination is unicast and it is not the best gw, 780 * false otherwise. 781 * 782 * This call might reallocate skb data. 783 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER. 784 */ 785 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, 786 struct sk_buff *skb) 787 { 788 struct batadv_neigh_node *neigh_curr = NULL; 789 struct batadv_neigh_node *neigh_old = NULL; 790 struct batadv_orig_node *orig_dst_node = NULL; 791 struct batadv_gw_node *gw_node = NULL; 792 struct batadv_gw_node *curr_gw = NULL; 793 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; 794 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 795 bool out_of_range = false; 796 u8 curr_tq_avg; 797 unsigned short vid; 798 799 vid = batadv_get_vid(skb, 0); 800 801 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 802 ethhdr->h_dest, vid); 803 if (!orig_dst_node) 804 goto out; 805 806 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node); 807 if (!gw_node) 808 goto out; 809 810 switch (atomic_read(&bat_priv->gw_mode)) { 811 case BATADV_GW_MODE_SERVER: 812 /* If we are a GW then we are our best GW. We can artificially 813 * set the tq towards ourself as the maximum value 814 */ 815 curr_tq_avg = BATADV_TQ_MAX_VALUE; 816 break; 817 case BATADV_GW_MODE_CLIENT: 818 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 819 if (!curr_gw) 820 goto out; 821 822 /* packet is going to our gateway */ 823 if (curr_gw->orig_node == orig_dst_node) 824 goto out; 825 826 /* If the dhcp packet has been sent to a different gw, 827 * we have to evaluate whether the old gw is still 828 * reliable enough 829 */ 830 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node, 831 NULL); 832 if (!neigh_curr) 833 goto out; 834 835 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr, 836 BATADV_IF_DEFAULT); 837 if (!curr_ifinfo) 838 goto out; 839 840 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg; 841 batadv_neigh_ifinfo_free_ref(curr_ifinfo); 842 843 break; 844 case BATADV_GW_MODE_OFF: 845 default: 846 goto out; 847 } 848 849 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL); 850 if (!neigh_old) 851 goto out; 852 853 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT); 854 if (!old_ifinfo) 855 goto out; 856 857 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD) 858 out_of_range = true; 859 batadv_neigh_ifinfo_free_ref(old_ifinfo); 860 861 out: 862 if (orig_dst_node) 863 batadv_orig_node_free_ref(orig_dst_node); 864 if (curr_gw) 865 batadv_gw_node_free_ref(curr_gw); 866 if (gw_node) 867 batadv_gw_node_free_ref(gw_node); 868 if (neigh_old) 869 batadv_neigh_node_free_ref(neigh_old); 870 if (neigh_curr) 871 batadv_neigh_node_free_ref(neigh_curr); 872 return out_of_range; 873 } 874