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/jiffies.h> 31 #include <linux/kernel.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 static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node) 64 { 65 if (atomic_dec_and_test(&gw_node->refcount)) { 66 batadv_orig_node_free_ref(gw_node->orig_node); 67 kfree_rcu(gw_node, rcu); 68 } 69 } 70 71 static struct batadv_gw_node * 72 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv) 73 { 74 struct batadv_gw_node *gw_node; 75 76 rcu_read_lock(); 77 gw_node = rcu_dereference(bat_priv->gw.curr_gw); 78 if (!gw_node) 79 goto out; 80 81 if (!atomic_inc_not_zero(&gw_node->refcount)) 82 gw_node = NULL; 83 84 out: 85 rcu_read_unlock(); 86 return gw_node; 87 } 88 89 struct batadv_orig_node * 90 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv) 91 { 92 struct batadv_gw_node *gw_node; 93 struct batadv_orig_node *orig_node = NULL; 94 95 gw_node = batadv_gw_get_selected_gw_node(bat_priv); 96 if (!gw_node) 97 goto out; 98 99 rcu_read_lock(); 100 orig_node = gw_node->orig_node; 101 if (!orig_node) 102 goto unlock; 103 104 if (!atomic_inc_not_zero(&orig_node->refcount)) 105 orig_node = NULL; 106 107 unlock: 108 rcu_read_unlock(); 109 out: 110 if (gw_node) 111 batadv_gw_node_free_ref(gw_node); 112 return orig_node; 113 } 114 115 static void batadv_gw_select(struct batadv_priv *bat_priv, 116 struct batadv_gw_node *new_gw_node) 117 { 118 struct batadv_gw_node *curr_gw_node; 119 120 spin_lock_bh(&bat_priv->gw.list_lock); 121 122 if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount)) 123 new_gw_node = NULL; 124 125 curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1); 126 rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node); 127 128 if (curr_gw_node) 129 batadv_gw_node_free_ref(curr_gw_node); 130 131 spin_unlock_bh(&bat_priv->gw.list_lock); 132 } 133 134 /** 135 * batadv_gw_reselect - force a gateway reselection 136 * @bat_priv: the bat priv with all the soft interface information 137 * 138 * Set a flag to remind the GW component to perform a new gateway reselection. 139 * However this function does not ensure that the current gateway is going to be 140 * deselected. The reselection mechanism may elect the same gateway once again. 141 * 142 * This means that invoking batadv_gw_reselect() does not guarantee a gateway 143 * change and therefore a uevent is not necessarily expected. 144 */ 145 void batadv_gw_reselect(struct batadv_priv *bat_priv) 146 { 147 atomic_set(&bat_priv->gw.reselect, 1); 148 } 149 150 static struct batadv_gw_node * 151 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv) 152 { 153 struct batadv_neigh_node *router; 154 struct batadv_neigh_ifinfo *router_ifinfo; 155 struct batadv_gw_node *gw_node, *curr_gw = NULL; 156 uint32_t max_gw_factor = 0, tmp_gw_factor = 0; 157 uint32_t gw_divisor; 158 uint8_t max_tq = 0; 159 uint8_t tq_avg; 160 struct batadv_orig_node *orig_node; 161 162 gw_divisor = BATADV_TQ_LOCAL_WINDOW_SIZE * BATADV_TQ_LOCAL_WINDOW_SIZE; 163 gw_divisor *= 64; 164 165 rcu_read_lock(); 166 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 167 if (gw_node->deleted) 168 continue; 169 170 orig_node = gw_node->orig_node; 171 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 172 if (!router) 173 continue; 174 175 router_ifinfo = batadv_neigh_ifinfo_get(router, 176 BATADV_IF_DEFAULT); 177 if (!router_ifinfo) 178 goto next; 179 180 if (!atomic_inc_not_zero(&gw_node->refcount)) 181 goto next; 182 183 tq_avg = router_ifinfo->bat_iv.tq_avg; 184 185 switch (atomic_read(&bat_priv->gw_sel_class)) { 186 case 1: /* fast connection */ 187 tmp_gw_factor = tq_avg * tq_avg; 188 tmp_gw_factor *= gw_node->bandwidth_down; 189 tmp_gw_factor *= 100 * 100; 190 tmp_gw_factor /= gw_divisor; 191 192 if ((tmp_gw_factor > max_gw_factor) || 193 ((tmp_gw_factor == max_gw_factor) && 194 (tq_avg > max_tq))) { 195 if (curr_gw) 196 batadv_gw_node_free_ref(curr_gw); 197 curr_gw = gw_node; 198 atomic_inc(&curr_gw->refcount); 199 } 200 break; 201 202 default: /* 2: stable connection (use best statistic) 203 * 3: fast-switch (use best statistic but change as 204 * soon as a better gateway appears) 205 * XX: late-switch (use best statistic but change as 206 * soon as a better gateway appears which has 207 * $routing_class more tq points) 208 */ 209 if (tq_avg > max_tq) { 210 if (curr_gw) 211 batadv_gw_node_free_ref(curr_gw); 212 curr_gw = gw_node; 213 atomic_inc(&curr_gw->refcount); 214 } 215 break; 216 } 217 218 if (tq_avg > max_tq) 219 max_tq = tq_avg; 220 221 if (tmp_gw_factor > max_gw_factor) 222 max_gw_factor = tmp_gw_factor; 223 224 batadv_gw_node_free_ref(gw_node); 225 226 next: 227 batadv_neigh_node_free_ref(router); 228 if (router_ifinfo) 229 batadv_neigh_ifinfo_free_ref(router_ifinfo); 230 } 231 rcu_read_unlock(); 232 233 return curr_gw; 234 } 235 236 /** 237 * batadv_gw_check_client_stop - check if client mode has been switched off 238 * @bat_priv: the bat priv with all the soft interface information 239 * 240 * This function assumes the caller has checked that the gw state *is actually 241 * changing*. This function is not supposed to be called when there is no state 242 * change. 243 */ 244 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv) 245 { 246 struct batadv_gw_node *curr_gw; 247 248 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT) 249 return; 250 251 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 252 if (!curr_gw) 253 return; 254 255 /* deselect the current gateway so that next time that client mode is 256 * enabled a proper GW_ADD event can be sent 257 */ 258 batadv_gw_select(bat_priv, NULL); 259 260 /* if batman-adv is switching the gw client mode off and a gateway was 261 * already selected, send a DEL uevent 262 */ 263 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL); 264 265 batadv_gw_node_free_ref(curr_gw); 266 } 267 268 void batadv_gw_election(struct batadv_priv *bat_priv) 269 { 270 struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL; 271 struct batadv_neigh_node *router = NULL; 272 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 273 char gw_addr[18] = { '\0' }; 274 275 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT) 276 goto out; 277 278 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 279 280 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw) 281 goto out; 282 283 next_gw = batadv_gw_get_best_gw_node(bat_priv); 284 285 if (curr_gw == next_gw) 286 goto out; 287 288 if (next_gw) { 289 sprintf(gw_addr, "%pM", next_gw->orig_node->orig); 290 291 router = batadv_orig_router_get(next_gw->orig_node, 292 BATADV_IF_DEFAULT); 293 if (!router) { 294 batadv_gw_reselect(bat_priv); 295 goto out; 296 } 297 298 router_ifinfo = batadv_neigh_ifinfo_get(router, 299 BATADV_IF_DEFAULT); 300 if (!router_ifinfo) { 301 batadv_gw_reselect(bat_priv); 302 goto out; 303 } 304 } 305 306 if ((curr_gw) && (!next_gw)) { 307 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 308 "Removing selected gateway - no gateway in range\n"); 309 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, 310 NULL); 311 } else if ((!curr_gw) && (next_gw)) { 312 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 313 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 314 next_gw->orig_node->orig, 315 next_gw->bandwidth_down / 10, 316 next_gw->bandwidth_down % 10, 317 next_gw->bandwidth_up / 10, 318 next_gw->bandwidth_up % 10, 319 router_ifinfo->bat_iv.tq_avg); 320 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD, 321 gw_addr); 322 } else { 323 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 324 "Changing 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_CHANGE, 332 gw_addr); 333 } 334 335 batadv_gw_select(bat_priv, next_gw); 336 337 out: 338 if (curr_gw) 339 batadv_gw_node_free_ref(curr_gw); 340 if (next_gw) 341 batadv_gw_node_free_ref(next_gw); 342 if (router) 343 batadv_neigh_node_free_ref(router); 344 if (router_ifinfo) 345 batadv_neigh_ifinfo_free_ref(router_ifinfo); 346 } 347 348 void batadv_gw_check_election(struct batadv_priv *bat_priv, 349 struct batadv_orig_node *orig_node) 350 { 351 struct batadv_neigh_ifinfo *router_orig_tq = NULL; 352 struct batadv_neigh_ifinfo *router_gw_tq = NULL; 353 struct batadv_orig_node *curr_gw_orig; 354 struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL; 355 uint8_t gw_tq_avg, orig_tq_avg; 356 357 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); 358 if (!curr_gw_orig) 359 goto reselect; 360 361 router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT); 362 if (!router_gw) 363 goto reselect; 364 365 router_gw_tq = batadv_neigh_ifinfo_get(router_gw, 366 BATADV_IF_DEFAULT); 367 if (!router_gw_tq) 368 goto reselect; 369 370 /* this node already is the gateway */ 371 if (curr_gw_orig == orig_node) 372 goto out; 373 374 router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT); 375 if (!router_orig) 376 goto out; 377 378 router_orig_tq = batadv_neigh_ifinfo_get(router_orig, 379 BATADV_IF_DEFAULT); 380 if (!router_orig_tq) 381 goto out; 382 383 gw_tq_avg = router_gw_tq->bat_iv.tq_avg; 384 orig_tq_avg = router_orig_tq->bat_iv.tq_avg; 385 386 /* the TQ value has to be better */ 387 if (orig_tq_avg < gw_tq_avg) 388 goto out; 389 390 /* if the routing class is greater than 3 the value tells us how much 391 * greater the TQ value of the new gateway must be 392 */ 393 if ((atomic_read(&bat_priv->gw_sel_class) > 3) && 394 (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class))) 395 goto out; 396 397 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 398 "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n", 399 gw_tq_avg, orig_tq_avg); 400 401 reselect: 402 batadv_gw_reselect(bat_priv); 403 out: 404 if (curr_gw_orig) 405 batadv_orig_node_free_ref(curr_gw_orig); 406 if (router_gw) 407 batadv_neigh_node_free_ref(router_gw); 408 if (router_orig) 409 batadv_neigh_node_free_ref(router_orig); 410 if (router_gw_tq) 411 batadv_neigh_ifinfo_free_ref(router_gw_tq); 412 if (router_orig_tq) 413 batadv_neigh_ifinfo_free_ref(router_orig_tq); 414 } 415 416 /** 417 * batadv_gw_node_add - add gateway node to list of available gateways 418 * @bat_priv: the bat priv with all the soft interface information 419 * @orig_node: originator announcing gateway capabilities 420 * @gateway: announced bandwidth information 421 */ 422 static void batadv_gw_node_add(struct batadv_priv *bat_priv, 423 struct batadv_orig_node *orig_node, 424 struct batadv_tvlv_gateway_data *gateway) 425 { 426 struct batadv_gw_node *gw_node; 427 428 if (gateway->bandwidth_down == 0) 429 return; 430 431 if (!atomic_inc_not_zero(&orig_node->refcount)) 432 return; 433 434 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); 435 if (!gw_node) { 436 batadv_orig_node_free_ref(orig_node); 437 return; 438 } 439 440 INIT_HLIST_NODE(&gw_node->list); 441 gw_node->orig_node = orig_node; 442 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 443 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 444 atomic_set(&gw_node->refcount, 1); 445 446 spin_lock_bh(&bat_priv->gw.list_lock); 447 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list); 448 spin_unlock_bh(&bat_priv->gw.list_lock); 449 450 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 451 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", 452 orig_node->orig, 453 ntohl(gateway->bandwidth_down) / 10, 454 ntohl(gateway->bandwidth_down) % 10, 455 ntohl(gateway->bandwidth_up) / 10, 456 ntohl(gateway->bandwidth_up) % 10); 457 } 458 459 /** 460 * batadv_gw_node_get - retrieve gateway node from list of available gateways 461 * @bat_priv: the bat priv with all the soft interface information 462 * @orig_node: originator announcing gateway capabilities 463 * 464 * Returns gateway node if found or NULL otherwise. 465 */ 466 static struct batadv_gw_node * 467 batadv_gw_node_get(struct batadv_priv *bat_priv, 468 struct batadv_orig_node *orig_node) 469 { 470 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL; 471 472 rcu_read_lock(); 473 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) { 474 if (gw_node_tmp->orig_node != orig_node) 475 continue; 476 477 if (gw_node_tmp->deleted) 478 continue; 479 480 if (!atomic_inc_not_zero(&gw_node_tmp->refcount)) 481 continue; 482 483 gw_node = gw_node_tmp; 484 break; 485 } 486 rcu_read_unlock(); 487 488 return gw_node; 489 } 490 491 /** 492 * batadv_gw_node_update - update list of available gateways with changed 493 * bandwidth information 494 * @bat_priv: the bat priv with all the soft interface information 495 * @orig_node: originator announcing gateway capabilities 496 * @gateway: announced bandwidth information 497 */ 498 void batadv_gw_node_update(struct batadv_priv *bat_priv, 499 struct batadv_orig_node *orig_node, 500 struct batadv_tvlv_gateway_data *gateway) 501 { 502 struct batadv_gw_node *gw_node, *curr_gw = NULL; 503 504 gw_node = batadv_gw_node_get(bat_priv, orig_node); 505 if (!gw_node) { 506 batadv_gw_node_add(bat_priv, orig_node, gateway); 507 goto out; 508 } 509 510 if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) && 511 (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))) 512 goto out; 513 514 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 515 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n", 516 orig_node->orig, 517 gw_node->bandwidth_down / 10, 518 gw_node->bandwidth_down % 10, 519 gw_node->bandwidth_up / 10, 520 gw_node->bandwidth_up % 10, 521 ntohl(gateway->bandwidth_down) / 10, 522 ntohl(gateway->bandwidth_down) % 10, 523 ntohl(gateway->bandwidth_up) / 10, 524 ntohl(gateway->bandwidth_up) % 10); 525 526 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 527 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 528 529 gw_node->deleted = 0; 530 if (ntohl(gateway->bandwidth_down) == 0) { 531 gw_node->deleted = jiffies; 532 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 533 "Gateway %pM removed from gateway list\n", 534 orig_node->orig); 535 536 /* Note: We don't need a NULL check here, since curr_gw never 537 * gets dereferenced. 538 */ 539 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 540 if (gw_node == curr_gw) 541 batadv_gw_reselect(bat_priv); 542 } 543 544 out: 545 if (curr_gw) 546 batadv_gw_node_free_ref(curr_gw); 547 if (gw_node) 548 batadv_gw_node_free_ref(gw_node); 549 } 550 551 void batadv_gw_node_delete(struct batadv_priv *bat_priv, 552 struct batadv_orig_node *orig_node) 553 { 554 struct batadv_tvlv_gateway_data gateway; 555 556 gateway.bandwidth_down = 0; 557 gateway.bandwidth_up = 0; 558 559 batadv_gw_node_update(bat_priv, orig_node, &gateway); 560 } 561 562 void batadv_gw_node_purge(struct batadv_priv *bat_priv) 563 { 564 struct batadv_gw_node *gw_node, *curr_gw; 565 struct hlist_node *node_tmp; 566 unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT); 567 int do_reselect = 0; 568 569 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 570 571 spin_lock_bh(&bat_priv->gw.list_lock); 572 573 hlist_for_each_entry_safe(gw_node, node_tmp, 574 &bat_priv->gw.list, list) { 575 if (((!gw_node->deleted) || 576 (time_before(jiffies, gw_node->deleted + timeout))) && 577 atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE) 578 continue; 579 580 if (curr_gw == gw_node) 581 do_reselect = 1; 582 583 hlist_del_rcu(&gw_node->list); 584 batadv_gw_node_free_ref(gw_node); 585 } 586 587 spin_unlock_bh(&bat_priv->gw.list_lock); 588 589 /* gw_reselect() needs to acquire the gw_list_lock */ 590 if (do_reselect) 591 batadv_gw_reselect(bat_priv); 592 593 if (curr_gw) 594 batadv_gw_node_free_ref(curr_gw); 595 } 596 597 /* fails if orig_node has no router */ 598 static int batadv_write_buffer_text(struct batadv_priv *bat_priv, 599 struct seq_file *seq, 600 const struct batadv_gw_node *gw_node) 601 { 602 struct batadv_gw_node *curr_gw; 603 struct batadv_neigh_node *router; 604 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 605 int ret = -1; 606 607 router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT); 608 if (!router) 609 goto out; 610 611 router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT); 612 if (!router_ifinfo) 613 goto out; 614 615 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 616 617 seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n", 618 (curr_gw == gw_node ? "=>" : " "), 619 gw_node->orig_node->orig, 620 router_ifinfo->bat_iv.tq_avg, router->addr, 621 router->if_incoming->net_dev->name, 622 gw_node->bandwidth_down / 10, 623 gw_node->bandwidth_down % 10, 624 gw_node->bandwidth_up / 10, 625 gw_node->bandwidth_up % 10); 626 ret = seq_has_overflowed(seq) ? -1 : 0; 627 628 if (curr_gw) 629 batadv_gw_node_free_ref(curr_gw); 630 out: 631 if (router_ifinfo) 632 batadv_neigh_ifinfo_free_ref(router_ifinfo); 633 if (router) 634 batadv_neigh_node_free_ref(router); 635 return ret; 636 } 637 638 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset) 639 { 640 struct net_device *net_dev = (struct net_device *)seq->private; 641 struct batadv_priv *bat_priv = netdev_priv(net_dev); 642 struct batadv_hard_iface *primary_if; 643 struct batadv_gw_node *gw_node; 644 int gw_count = 0; 645 646 primary_if = batadv_seq_print_text_primary_if_get(seq); 647 if (!primary_if) 648 goto out; 649 650 seq_printf(seq, 651 " %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n", 652 "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF", 653 BATADV_SOURCE_VERSION, primary_if->net_dev->name, 654 primary_if->net_dev->dev_addr, net_dev->name); 655 656 rcu_read_lock(); 657 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) { 658 if (gw_node->deleted) 659 continue; 660 661 /* fails if orig_node has no router */ 662 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0) 663 continue; 664 665 gw_count++; 666 } 667 rcu_read_unlock(); 668 669 if (gw_count == 0) 670 seq_puts(seq, "No gateways in range ...\n"); 671 672 out: 673 if (primary_if) 674 batadv_hardif_free_ref(primary_if); 675 return 0; 676 } 677 678 /** 679 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message 680 * @skb: the packet to check 681 * @header_len: a pointer to the batman-adv header size 682 * @chaddr: buffer where the client address will be stored. Valid 683 * only if the function returns BATADV_DHCP_TO_CLIENT 684 * 685 * Returns: 686 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error 687 * while parsing it 688 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server 689 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client 690 * 691 * This function may re-allocate the data buffer of the skb passed as argument. 692 */ 693 enum batadv_dhcp_recipient 694 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, 695 uint8_t *chaddr) 696 { 697 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO; 698 struct ethhdr *ethhdr; 699 struct iphdr *iphdr; 700 struct ipv6hdr *ipv6hdr; 701 struct udphdr *udphdr; 702 struct vlan_ethhdr *vhdr; 703 int chaddr_offset; 704 __be16 proto; 705 uint8_t *p; 706 707 /* check for ethernet header */ 708 if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) 709 return BATADV_DHCP_NO; 710 711 ethhdr = eth_hdr(skb); 712 proto = ethhdr->h_proto; 713 *header_len += ETH_HLEN; 714 715 /* check for initial vlan header */ 716 if (proto == htons(ETH_P_8021Q)) { 717 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) 718 return BATADV_DHCP_NO; 719 720 vhdr = vlan_eth_hdr(skb); 721 proto = vhdr->h_vlan_encapsulated_proto; 722 *header_len += VLAN_HLEN; 723 } 724 725 /* check for ip header */ 726 switch (proto) { 727 case htons(ETH_P_IP): 728 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) 729 return BATADV_DHCP_NO; 730 731 iphdr = (struct iphdr *)(skb->data + *header_len); 732 *header_len += iphdr->ihl * 4; 733 734 /* check for udp header */ 735 if (iphdr->protocol != IPPROTO_UDP) 736 return BATADV_DHCP_NO; 737 738 break; 739 case htons(ETH_P_IPV6): 740 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) 741 return BATADV_DHCP_NO; 742 743 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); 744 *header_len += sizeof(*ipv6hdr); 745 746 /* check for udp header */ 747 if (ipv6hdr->nexthdr != IPPROTO_UDP) 748 return BATADV_DHCP_NO; 749 750 break; 751 default: 752 return BATADV_DHCP_NO; 753 } 754 755 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) 756 return BATADV_DHCP_NO; 757 758 udphdr = (struct udphdr *)(skb->data + *header_len); 759 *header_len += sizeof(*udphdr); 760 761 /* check for bootp port */ 762 switch (proto) { 763 case htons(ETH_P_IP): 764 if (udphdr->dest == htons(67)) 765 ret = BATADV_DHCP_TO_SERVER; 766 else if (udphdr->source == htons(67)) 767 ret = BATADV_DHCP_TO_CLIENT; 768 break; 769 case htons(ETH_P_IPV6): 770 if (udphdr->dest == htons(547)) 771 ret = BATADV_DHCP_TO_SERVER; 772 else if (udphdr->source == htons(547)) 773 ret = BATADV_DHCP_TO_CLIENT; 774 break; 775 } 776 777 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; 778 /* store the client address if the message is going to a client */ 779 if (ret == BATADV_DHCP_TO_CLIENT && 780 pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { 781 /* check if the DHCP packet carries an Ethernet DHCP */ 782 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; 783 if (*p != BATADV_DHCP_HTYPE_ETHERNET) 784 return BATADV_DHCP_NO; 785 786 /* check if the DHCP packet carries a valid Ethernet address */ 787 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET; 788 if (*p != ETH_ALEN) 789 return BATADV_DHCP_NO; 790 791 ether_addr_copy(chaddr, skb->data + chaddr_offset); 792 } 793 794 return ret; 795 } 796 797 /** 798 * batadv_gw_out_of_range - check if the dhcp request destination is the best gw 799 * @bat_priv: the bat priv with all the soft interface information 800 * @skb: the outgoing packet 801 * 802 * Check if the skb is a DHCP request and if it is sent to the current best GW 803 * server. Due to topology changes it may be the case that the GW server 804 * previously selected is not the best one anymore. 805 * 806 * Returns true if the packet destination is unicast and it is not the best gw, 807 * false otherwise. 808 * 809 * This call might reallocate skb data. 810 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER. 811 */ 812 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, 813 struct sk_buff *skb) 814 { 815 struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL; 816 struct batadv_orig_node *orig_dst_node = NULL; 817 struct batadv_gw_node *gw_node = NULL, *curr_gw = NULL; 818 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; 819 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 820 bool out_of_range = false; 821 uint8_t curr_tq_avg; 822 unsigned short vid; 823 824 vid = batadv_get_vid(skb, 0); 825 826 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 827 ethhdr->h_dest, vid); 828 if (!orig_dst_node) 829 goto out; 830 831 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node); 832 if (!gw_node) 833 goto out; 834 835 switch (atomic_read(&bat_priv->gw_mode)) { 836 case BATADV_GW_MODE_SERVER: 837 /* If we are a GW then we are our best GW. We can artificially 838 * set the tq towards ourself as the maximum value 839 */ 840 curr_tq_avg = BATADV_TQ_MAX_VALUE; 841 break; 842 case BATADV_GW_MODE_CLIENT: 843 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 844 if (!curr_gw) 845 goto out; 846 847 /* packet is going to our gateway */ 848 if (curr_gw->orig_node == orig_dst_node) 849 goto out; 850 851 /* If the dhcp packet has been sent to a different gw, 852 * we have to evaluate whether the old gw is still 853 * reliable enough 854 */ 855 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node, 856 NULL); 857 if (!neigh_curr) 858 goto out; 859 860 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr, 861 BATADV_IF_DEFAULT); 862 if (!curr_ifinfo) 863 goto out; 864 865 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg; 866 batadv_neigh_ifinfo_free_ref(curr_ifinfo); 867 868 break; 869 case BATADV_GW_MODE_OFF: 870 default: 871 goto out; 872 } 873 874 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL); 875 if (!neigh_old) 876 goto out; 877 878 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT); 879 if (!old_ifinfo) 880 goto out; 881 882 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD) 883 out_of_range = true; 884 batadv_neigh_ifinfo_free_ref(old_ifinfo); 885 886 out: 887 if (orig_dst_node) 888 batadv_orig_node_free_ref(orig_dst_node); 889 if (curr_gw) 890 batadv_gw_node_free_ref(curr_gw); 891 if (gw_node) 892 batadv_gw_node_free_ref(gw_node); 893 if (neigh_old) 894 batadv_neigh_node_free_ref(neigh_old); 895 if (neigh_curr) 896 batadv_neigh_node_free_ref(neigh_curr); 897 return out_of_range; 898 } 899