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 if (!hlist_unhashed(&gw_node->list)) { 531 hlist_del_init_rcu(&gw_node->list); 532 batadv_gw_node_free_ref(gw_node); 533 } 534 spin_unlock_bh(&bat_priv->gw.list_lock); 535 536 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 537 if (gw_node == curr_gw) 538 batadv_gw_reselect(bat_priv); 539 540 if (curr_gw) 541 batadv_gw_node_free_ref(curr_gw); 542 } 543 544 out: 545 if (gw_node) 546 batadv_gw_node_free_ref(gw_node); 547 } 548 549 void batadv_gw_node_delete(struct batadv_priv *bat_priv, 550 struct batadv_orig_node *orig_node) 551 { 552 struct batadv_tvlv_gateway_data gateway; 553 554 gateway.bandwidth_down = 0; 555 gateway.bandwidth_up = 0; 556 557 batadv_gw_node_update(bat_priv, orig_node, &gateway); 558 } 559 560 void batadv_gw_node_free(struct batadv_priv *bat_priv) 561 { 562 struct batadv_gw_node *gw_node; 563 struct hlist_node *node_tmp; 564 565 spin_lock_bh(&bat_priv->gw.list_lock); 566 hlist_for_each_entry_safe(gw_node, node_tmp, 567 &bat_priv->gw.list, list) { 568 hlist_del_init_rcu(&gw_node->list); 569 batadv_gw_node_free_ref(gw_node); 570 } 571 spin_unlock_bh(&bat_priv->gw.list_lock); 572 } 573 574 /* fails if orig_node has no router */ 575 static int batadv_write_buffer_text(struct batadv_priv *bat_priv, 576 struct seq_file *seq, 577 const struct batadv_gw_node *gw_node) 578 { 579 struct batadv_gw_node *curr_gw; 580 struct batadv_neigh_node *router; 581 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 582 int ret = -1; 583 584 router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT); 585 if (!router) 586 goto out; 587 588 router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT); 589 if (!router_ifinfo) 590 goto out; 591 592 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 593 594 seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n", 595 (curr_gw == gw_node ? "=>" : " "), 596 gw_node->orig_node->orig, 597 router_ifinfo->bat_iv.tq_avg, router->addr, 598 router->if_incoming->net_dev->name, 599 gw_node->bandwidth_down / 10, 600 gw_node->bandwidth_down % 10, 601 gw_node->bandwidth_up / 10, 602 gw_node->bandwidth_up % 10); 603 ret = seq_has_overflowed(seq) ? -1 : 0; 604 605 if (curr_gw) 606 batadv_gw_node_free_ref(curr_gw); 607 out: 608 if (router_ifinfo) 609 batadv_neigh_ifinfo_free_ref(router_ifinfo); 610 if (router) 611 batadv_neigh_node_free_ref(router); 612 return ret; 613 } 614 615 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset) 616 { 617 struct net_device *net_dev = (struct net_device *)seq->private; 618 struct batadv_priv *bat_priv = netdev_priv(net_dev); 619 struct batadv_hard_iface *primary_if; 620 struct batadv_gw_node *gw_node; 621 int gw_count = 0; 622 623 primary_if = batadv_seq_print_text_primary_if_get(seq); 624 if (!primary_if) 625 goto out; 626 627 seq_printf(seq, 628 " %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n", 629 "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF", 630 BATADV_SOURCE_VERSION, primary_if->net_dev->name, 631 primary_if->net_dev->dev_addr, net_dev->name); 632 633 rcu_read_lock(); 634 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 635 /* fails if orig_node has no router */ 636 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0) 637 continue; 638 639 gw_count++; 640 } 641 rcu_read_unlock(); 642 643 if (gw_count == 0) 644 seq_puts(seq, "No gateways in range ...\n"); 645 646 out: 647 if (primary_if) 648 batadv_hardif_free_ref(primary_if); 649 return 0; 650 } 651 652 /** 653 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message 654 * @skb: the packet to check 655 * @header_len: a pointer to the batman-adv header size 656 * @chaddr: buffer where the client address will be stored. Valid 657 * only if the function returns BATADV_DHCP_TO_CLIENT 658 * 659 * Returns: 660 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error 661 * while parsing it 662 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server 663 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client 664 * 665 * This function may re-allocate the data buffer of the skb passed as argument. 666 */ 667 enum batadv_dhcp_recipient 668 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, 669 u8 *chaddr) 670 { 671 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO; 672 struct ethhdr *ethhdr; 673 struct iphdr *iphdr; 674 struct ipv6hdr *ipv6hdr; 675 struct udphdr *udphdr; 676 struct vlan_ethhdr *vhdr; 677 int chaddr_offset; 678 __be16 proto; 679 u8 *p; 680 681 /* check for ethernet header */ 682 if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) 683 return BATADV_DHCP_NO; 684 685 ethhdr = eth_hdr(skb); 686 proto = ethhdr->h_proto; 687 *header_len += ETH_HLEN; 688 689 /* check for initial vlan header */ 690 if (proto == htons(ETH_P_8021Q)) { 691 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) 692 return BATADV_DHCP_NO; 693 694 vhdr = vlan_eth_hdr(skb); 695 proto = vhdr->h_vlan_encapsulated_proto; 696 *header_len += VLAN_HLEN; 697 } 698 699 /* check for ip header */ 700 switch (proto) { 701 case htons(ETH_P_IP): 702 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) 703 return BATADV_DHCP_NO; 704 705 iphdr = (struct iphdr *)(skb->data + *header_len); 706 *header_len += iphdr->ihl * 4; 707 708 /* check for udp header */ 709 if (iphdr->protocol != IPPROTO_UDP) 710 return BATADV_DHCP_NO; 711 712 break; 713 case htons(ETH_P_IPV6): 714 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) 715 return BATADV_DHCP_NO; 716 717 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); 718 *header_len += sizeof(*ipv6hdr); 719 720 /* check for udp header */ 721 if (ipv6hdr->nexthdr != IPPROTO_UDP) 722 return BATADV_DHCP_NO; 723 724 break; 725 default: 726 return BATADV_DHCP_NO; 727 } 728 729 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) 730 return BATADV_DHCP_NO; 731 732 udphdr = (struct udphdr *)(skb->data + *header_len); 733 *header_len += sizeof(*udphdr); 734 735 /* check for bootp port */ 736 switch (proto) { 737 case htons(ETH_P_IP): 738 if (udphdr->dest == htons(67)) 739 ret = BATADV_DHCP_TO_SERVER; 740 else if (udphdr->source == htons(67)) 741 ret = BATADV_DHCP_TO_CLIENT; 742 break; 743 case htons(ETH_P_IPV6): 744 if (udphdr->dest == htons(547)) 745 ret = BATADV_DHCP_TO_SERVER; 746 else if (udphdr->source == htons(547)) 747 ret = BATADV_DHCP_TO_CLIENT; 748 break; 749 } 750 751 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; 752 /* store the client address if the message is going to a client */ 753 if (ret == BATADV_DHCP_TO_CLIENT && 754 pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { 755 /* check if the DHCP packet carries an Ethernet DHCP */ 756 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; 757 if (*p != BATADV_DHCP_HTYPE_ETHERNET) 758 return BATADV_DHCP_NO; 759 760 /* check if the DHCP packet carries a valid Ethernet address */ 761 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET; 762 if (*p != ETH_ALEN) 763 return BATADV_DHCP_NO; 764 765 ether_addr_copy(chaddr, skb->data + chaddr_offset); 766 } 767 768 return ret; 769 } 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; 790 struct batadv_neigh_node *neigh_old = NULL; 791 struct batadv_orig_node *orig_dst_node = NULL; 792 struct batadv_gw_node *gw_node = NULL; 793 struct batadv_gw_node *curr_gw = NULL; 794 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; 795 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 796 bool out_of_range = false; 797 u8 curr_tq_avg; 798 unsigned short vid; 799 800 vid = batadv_get_vid(skb, 0); 801 802 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 803 ethhdr->h_dest, vid); 804 if (!orig_dst_node) 805 goto out; 806 807 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node); 808 if (!gw_node) 809 goto out; 810 811 switch (atomic_read(&bat_priv->gw_mode)) { 812 case BATADV_GW_MODE_SERVER: 813 /* If we are a GW then we are our best GW. We can artificially 814 * set the tq towards ourself as the maximum value 815 */ 816 curr_tq_avg = BATADV_TQ_MAX_VALUE; 817 break; 818 case BATADV_GW_MODE_CLIENT: 819 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 820 if (!curr_gw) 821 goto out; 822 823 /* packet is going to our gateway */ 824 if (curr_gw->orig_node == orig_dst_node) 825 goto out; 826 827 /* If the dhcp packet has been sent to a different gw, 828 * we have to evaluate whether the old gw is still 829 * reliable enough 830 */ 831 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node, 832 NULL); 833 if (!neigh_curr) 834 goto out; 835 836 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr, 837 BATADV_IF_DEFAULT); 838 if (!curr_ifinfo) 839 goto out; 840 841 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg; 842 batadv_neigh_ifinfo_free_ref(curr_ifinfo); 843 844 break; 845 case BATADV_GW_MODE_OFF: 846 default: 847 goto out; 848 } 849 850 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL); 851 if (!neigh_old) 852 goto out; 853 854 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT); 855 if (!old_ifinfo) 856 goto out; 857 858 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD) 859 out_of_range = true; 860 batadv_neigh_ifinfo_free_ref(old_ifinfo); 861 862 out: 863 if (orig_dst_node) 864 batadv_orig_node_free_ref(orig_dst_node); 865 if (curr_gw) 866 batadv_gw_node_free_ref(curr_gw); 867 if (gw_node) 868 batadv_gw_node_free_ref(gw_node); 869 if (neigh_old) 870 batadv_neigh_node_free_ref(neigh_old); 871 if (neigh_curr) 872 batadv_neigh_node_free_ref(neigh_curr); 873 return out_of_range; 874 } 875