1 /* Copyright (C) 2009-2016 B.A.T.M.A.N. contributors: 2 * 3 * Marek Lindner 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of version 2 of the GNU General Public 7 * License as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, see <http://www.gnu.org/licenses/>. 16 */ 17 18 #include "gateway_client.h" 19 #include "main.h" 20 21 #include <linux/atomic.h> 22 #include <linux/byteorder/generic.h> 23 #include <linux/etherdevice.h> 24 #include <linux/fs.h> 25 #include <linux/if_ether.h> 26 #include <linux/if_vlan.h> 27 #include <linux/in.h> 28 #include <linux/ip.h> 29 #include <linux/ipv6.h> 30 #include <linux/kernel.h> 31 #include <linux/kref.h> 32 #include <linux/list.h> 33 #include <linux/netdevice.h> 34 #include <linux/rculist.h> 35 #include <linux/rcupdate.h> 36 #include <linux/seq_file.h> 37 #include <linux/skbuff.h> 38 #include <linux/slab.h> 39 #include <linux/spinlock.h> 40 #include <linux/stddef.h> 41 #include <linux/udp.h> 42 43 #include "gateway_common.h" 44 #include "hard-interface.h" 45 #include "log.h" 46 #include "originator.h" 47 #include "packet.h" 48 #include "routing.h" 49 #include "sysfs.h" 50 #include "translation-table.h" 51 52 /* These are the offsets of the "hw type" and "hw address length" in the dhcp 53 * packet starting at the beginning of the dhcp header 54 */ 55 #define BATADV_DHCP_HTYPE_OFFSET 1 56 #define BATADV_DHCP_HLEN_OFFSET 2 57 /* Value of htype representing Ethernet */ 58 #define BATADV_DHCP_HTYPE_ETHERNET 0x01 59 /* This is the offset of the "chaddr" field in the dhcp packet starting at the 60 * beginning of the dhcp header 61 */ 62 #define BATADV_DHCP_CHADDR_OFFSET 28 63 64 /** 65 * batadv_gw_node_release - release gw_node from lists and queue for free after 66 * rcu grace period 67 * @ref: kref pointer of the gw_node 68 */ 69 static void batadv_gw_node_release(struct kref *ref) 70 { 71 struct batadv_gw_node *gw_node; 72 73 gw_node = container_of(ref, struct batadv_gw_node, refcount); 74 75 batadv_orig_node_put(gw_node->orig_node); 76 kfree_rcu(gw_node, rcu); 77 } 78 79 /** 80 * batadv_gw_node_put - decrement the gw_node refcounter and possibly release it 81 * @gw_node: gateway node to free 82 */ 83 void batadv_gw_node_put(struct batadv_gw_node *gw_node) 84 { 85 kref_put(&gw_node->refcount, batadv_gw_node_release); 86 } 87 88 struct batadv_gw_node * 89 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv) 90 { 91 struct batadv_gw_node *gw_node; 92 93 rcu_read_lock(); 94 gw_node = rcu_dereference(bat_priv->gw.curr_gw); 95 if (!gw_node) 96 goto out; 97 98 if (!kref_get_unless_zero(&gw_node->refcount)) 99 gw_node = NULL; 100 101 out: 102 rcu_read_unlock(); 103 return gw_node; 104 } 105 106 struct batadv_orig_node * 107 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv) 108 { 109 struct batadv_gw_node *gw_node; 110 struct batadv_orig_node *orig_node = NULL; 111 112 gw_node = batadv_gw_get_selected_gw_node(bat_priv); 113 if (!gw_node) 114 goto out; 115 116 rcu_read_lock(); 117 orig_node = gw_node->orig_node; 118 if (!orig_node) 119 goto unlock; 120 121 if (!kref_get_unless_zero(&orig_node->refcount)) 122 orig_node = NULL; 123 124 unlock: 125 rcu_read_unlock(); 126 out: 127 if (gw_node) 128 batadv_gw_node_put(gw_node); 129 return orig_node; 130 } 131 132 static void batadv_gw_select(struct batadv_priv *bat_priv, 133 struct batadv_gw_node *new_gw_node) 134 { 135 struct batadv_gw_node *curr_gw_node; 136 137 spin_lock_bh(&bat_priv->gw.list_lock); 138 139 if (new_gw_node) 140 kref_get(&new_gw_node->refcount); 141 142 curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1); 143 rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node); 144 145 if (curr_gw_node) 146 batadv_gw_node_put(curr_gw_node); 147 148 spin_unlock_bh(&bat_priv->gw.list_lock); 149 } 150 151 /** 152 * batadv_gw_reselect - force a gateway reselection 153 * @bat_priv: the bat priv with all the soft interface information 154 * 155 * Set a flag to remind the GW component to perform a new gateway reselection. 156 * However this function does not ensure that the current gateway is going to be 157 * deselected. The reselection mechanism may elect the same gateway once again. 158 * 159 * This means that invoking batadv_gw_reselect() does not guarantee a gateway 160 * change and therefore a uevent is not necessarily expected. 161 */ 162 void batadv_gw_reselect(struct batadv_priv *bat_priv) 163 { 164 atomic_set(&bat_priv->gw.reselect, 1); 165 } 166 167 /** 168 * batadv_gw_check_client_stop - check if client mode has been switched off 169 * @bat_priv: the bat priv with all the soft interface information 170 * 171 * This function assumes the caller has checked that the gw state *is actually 172 * changing*. This function is not supposed to be called when there is no state 173 * change. 174 */ 175 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv) 176 { 177 struct batadv_gw_node *curr_gw; 178 179 if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT) 180 return; 181 182 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 183 if (!curr_gw) 184 return; 185 186 /* deselect the current gateway so that next time that client mode is 187 * enabled a proper GW_ADD event can be sent 188 */ 189 batadv_gw_select(bat_priv, NULL); 190 191 /* if batman-adv is switching the gw client mode off and a gateway was 192 * already selected, send a DEL uevent 193 */ 194 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL); 195 196 batadv_gw_node_put(curr_gw); 197 } 198 199 void batadv_gw_election(struct batadv_priv *bat_priv) 200 { 201 struct batadv_gw_node *curr_gw = NULL; 202 struct batadv_gw_node *next_gw = NULL; 203 struct batadv_neigh_node *router = NULL; 204 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 205 char gw_addr[18] = { '\0' }; 206 207 if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT) 208 goto out; 209 210 if (!bat_priv->algo_ops->gw.get_best_gw_node) 211 goto out; 212 213 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 214 215 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw) 216 goto out; 217 218 /* if gw.reselect is set to 1 it means that a previous call to 219 * gw.is_eligible() said that we have a new best GW, therefore it can 220 * now be picked from the list and selected 221 */ 222 next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv); 223 224 if (curr_gw == next_gw) 225 goto out; 226 227 if (next_gw) { 228 sprintf(gw_addr, "%pM", next_gw->orig_node->orig); 229 230 router = batadv_orig_router_get(next_gw->orig_node, 231 BATADV_IF_DEFAULT); 232 if (!router) { 233 batadv_gw_reselect(bat_priv); 234 goto out; 235 } 236 237 router_ifinfo = batadv_neigh_ifinfo_get(router, 238 BATADV_IF_DEFAULT); 239 if (!router_ifinfo) { 240 batadv_gw_reselect(bat_priv); 241 goto out; 242 } 243 } 244 245 if ((curr_gw) && (!next_gw)) { 246 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 247 "Removing selected gateway - no gateway in range\n"); 248 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, 249 NULL); 250 } else if ((!curr_gw) && (next_gw)) { 251 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 252 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 253 next_gw->orig_node->orig, 254 next_gw->bandwidth_down / 10, 255 next_gw->bandwidth_down % 10, 256 next_gw->bandwidth_up / 10, 257 next_gw->bandwidth_up % 10, 258 router_ifinfo->bat_iv.tq_avg); 259 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD, 260 gw_addr); 261 } else { 262 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 263 "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 264 next_gw->orig_node->orig, 265 next_gw->bandwidth_down / 10, 266 next_gw->bandwidth_down % 10, 267 next_gw->bandwidth_up / 10, 268 next_gw->bandwidth_up % 10, 269 router_ifinfo->bat_iv.tq_avg); 270 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE, 271 gw_addr); 272 } 273 274 batadv_gw_select(bat_priv, next_gw); 275 276 out: 277 if (curr_gw) 278 batadv_gw_node_put(curr_gw); 279 if (next_gw) 280 batadv_gw_node_put(next_gw); 281 if (router) 282 batadv_neigh_node_put(router); 283 if (router_ifinfo) 284 batadv_neigh_ifinfo_put(router_ifinfo); 285 } 286 287 void batadv_gw_check_election(struct batadv_priv *bat_priv, 288 struct batadv_orig_node *orig_node) 289 { 290 struct batadv_orig_node *curr_gw_orig; 291 292 /* abort immediately if the routing algorithm does not support gateway 293 * election 294 */ 295 if (!bat_priv->algo_ops->gw.is_eligible) 296 return; 297 298 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); 299 if (!curr_gw_orig) 300 goto reselect; 301 302 /* this node already is the gateway */ 303 if (curr_gw_orig == orig_node) 304 goto out; 305 306 if (!bat_priv->algo_ops->gw.is_eligible(bat_priv, curr_gw_orig, 307 orig_node)) 308 goto out; 309 310 reselect: 311 batadv_gw_reselect(bat_priv); 312 out: 313 if (curr_gw_orig) 314 batadv_orig_node_put(curr_gw_orig); 315 } 316 317 /** 318 * batadv_gw_node_add - add gateway node to list of available gateways 319 * @bat_priv: the bat priv with all the soft interface information 320 * @orig_node: originator announcing gateway capabilities 321 * @gateway: announced bandwidth information 322 */ 323 static void batadv_gw_node_add(struct batadv_priv *bat_priv, 324 struct batadv_orig_node *orig_node, 325 struct batadv_tvlv_gateway_data *gateway) 326 { 327 struct batadv_gw_node *gw_node; 328 329 if (gateway->bandwidth_down == 0) 330 return; 331 332 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); 333 if (!gw_node) 334 return; 335 336 kref_get(&orig_node->refcount); 337 INIT_HLIST_NODE(&gw_node->list); 338 gw_node->orig_node = orig_node; 339 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 340 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 341 kref_init(&gw_node->refcount); 342 343 spin_lock_bh(&bat_priv->gw.list_lock); 344 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list); 345 spin_unlock_bh(&bat_priv->gw.list_lock); 346 347 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 348 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", 349 orig_node->orig, 350 ntohl(gateway->bandwidth_down) / 10, 351 ntohl(gateway->bandwidth_down) % 10, 352 ntohl(gateway->bandwidth_up) / 10, 353 ntohl(gateway->bandwidth_up) % 10); 354 } 355 356 /** 357 * batadv_gw_node_get - retrieve gateway node from list of available gateways 358 * @bat_priv: the bat priv with all the soft interface information 359 * @orig_node: originator announcing gateway capabilities 360 * 361 * Return: gateway node if found or NULL otherwise. 362 */ 363 struct batadv_gw_node *batadv_gw_node_get(struct batadv_priv *bat_priv, 364 struct batadv_orig_node *orig_node) 365 { 366 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL; 367 368 rcu_read_lock(); 369 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) { 370 if (gw_node_tmp->orig_node != orig_node) 371 continue; 372 373 if (!kref_get_unless_zero(&gw_node_tmp->refcount)) 374 continue; 375 376 gw_node = gw_node_tmp; 377 break; 378 } 379 rcu_read_unlock(); 380 381 return gw_node; 382 } 383 384 /** 385 * batadv_gw_node_update - update list of available gateways with changed 386 * bandwidth information 387 * @bat_priv: the bat priv with all the soft interface information 388 * @orig_node: originator announcing gateway capabilities 389 * @gateway: announced bandwidth information 390 */ 391 void batadv_gw_node_update(struct batadv_priv *bat_priv, 392 struct batadv_orig_node *orig_node, 393 struct batadv_tvlv_gateway_data *gateway) 394 { 395 struct batadv_gw_node *gw_node, *curr_gw = NULL; 396 397 gw_node = batadv_gw_node_get(bat_priv, orig_node); 398 if (!gw_node) { 399 batadv_gw_node_add(bat_priv, orig_node, gateway); 400 goto out; 401 } 402 403 if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) && 404 (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))) 405 goto out; 406 407 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 408 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n", 409 orig_node->orig, 410 gw_node->bandwidth_down / 10, 411 gw_node->bandwidth_down % 10, 412 gw_node->bandwidth_up / 10, 413 gw_node->bandwidth_up % 10, 414 ntohl(gateway->bandwidth_down) / 10, 415 ntohl(gateway->bandwidth_down) % 10, 416 ntohl(gateway->bandwidth_up) / 10, 417 ntohl(gateway->bandwidth_up) % 10); 418 419 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 420 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 421 422 if (ntohl(gateway->bandwidth_down) == 0) { 423 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 424 "Gateway %pM removed from gateway list\n", 425 orig_node->orig); 426 427 /* Note: We don't need a NULL check here, since curr_gw never 428 * gets dereferenced. 429 */ 430 spin_lock_bh(&bat_priv->gw.list_lock); 431 if (!hlist_unhashed(&gw_node->list)) { 432 hlist_del_init_rcu(&gw_node->list); 433 batadv_gw_node_put(gw_node); 434 } 435 spin_unlock_bh(&bat_priv->gw.list_lock); 436 437 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 438 if (gw_node == curr_gw) 439 batadv_gw_reselect(bat_priv); 440 441 if (curr_gw) 442 batadv_gw_node_put(curr_gw); 443 } 444 445 out: 446 if (gw_node) 447 batadv_gw_node_put(gw_node); 448 } 449 450 void batadv_gw_node_delete(struct batadv_priv *bat_priv, 451 struct batadv_orig_node *orig_node) 452 { 453 struct batadv_tvlv_gateway_data gateway; 454 455 gateway.bandwidth_down = 0; 456 gateway.bandwidth_up = 0; 457 458 batadv_gw_node_update(bat_priv, orig_node, &gateway); 459 } 460 461 void batadv_gw_node_free(struct batadv_priv *bat_priv) 462 { 463 struct batadv_gw_node *gw_node; 464 struct hlist_node *node_tmp; 465 466 spin_lock_bh(&bat_priv->gw.list_lock); 467 hlist_for_each_entry_safe(gw_node, node_tmp, 468 &bat_priv->gw.list, list) { 469 hlist_del_init_rcu(&gw_node->list); 470 batadv_gw_node_put(gw_node); 471 } 472 spin_unlock_bh(&bat_priv->gw.list_lock); 473 } 474 475 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset) 476 { 477 struct net_device *net_dev = (struct net_device *)seq->private; 478 struct batadv_priv *bat_priv = netdev_priv(net_dev); 479 struct batadv_hard_iface *primary_if; 480 481 primary_if = batadv_seq_print_text_primary_if_get(seq); 482 if (!primary_if) 483 return 0; 484 485 seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s %s)]\n", 486 BATADV_SOURCE_VERSION, primary_if->net_dev->name, 487 primary_if->net_dev->dev_addr, net_dev->name, 488 bat_priv->algo_ops->name); 489 490 batadv_hardif_put(primary_if); 491 492 if (!bat_priv->algo_ops->gw.print) { 493 seq_puts(seq, 494 "No printing function for this routing protocol\n"); 495 return 0; 496 } 497 498 bat_priv->algo_ops->gw.print(bat_priv, seq); 499 500 return 0; 501 } 502 503 /** 504 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message 505 * @skb: the packet to check 506 * @header_len: a pointer to the batman-adv header size 507 * @chaddr: buffer where the client address will be stored. Valid 508 * only if the function returns BATADV_DHCP_TO_CLIENT 509 * 510 * This function may re-allocate the data buffer of the skb passed as argument. 511 * 512 * Return: 513 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error 514 * while parsing it 515 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server 516 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client 517 */ 518 enum batadv_dhcp_recipient 519 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, 520 u8 *chaddr) 521 { 522 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO; 523 struct ethhdr *ethhdr; 524 struct iphdr *iphdr; 525 struct ipv6hdr *ipv6hdr; 526 struct udphdr *udphdr; 527 struct vlan_ethhdr *vhdr; 528 int chaddr_offset; 529 __be16 proto; 530 u8 *p; 531 532 /* check for ethernet header */ 533 if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) 534 return BATADV_DHCP_NO; 535 536 ethhdr = eth_hdr(skb); 537 proto = ethhdr->h_proto; 538 *header_len += ETH_HLEN; 539 540 /* check for initial vlan header */ 541 if (proto == htons(ETH_P_8021Q)) { 542 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) 543 return BATADV_DHCP_NO; 544 545 vhdr = vlan_eth_hdr(skb); 546 proto = vhdr->h_vlan_encapsulated_proto; 547 *header_len += VLAN_HLEN; 548 } 549 550 /* check for ip header */ 551 switch (proto) { 552 case htons(ETH_P_IP): 553 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) 554 return BATADV_DHCP_NO; 555 556 iphdr = (struct iphdr *)(skb->data + *header_len); 557 *header_len += iphdr->ihl * 4; 558 559 /* check for udp header */ 560 if (iphdr->protocol != IPPROTO_UDP) 561 return BATADV_DHCP_NO; 562 563 break; 564 case htons(ETH_P_IPV6): 565 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) 566 return BATADV_DHCP_NO; 567 568 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); 569 *header_len += sizeof(*ipv6hdr); 570 571 /* check for udp header */ 572 if (ipv6hdr->nexthdr != IPPROTO_UDP) 573 return BATADV_DHCP_NO; 574 575 break; 576 default: 577 return BATADV_DHCP_NO; 578 } 579 580 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) 581 return BATADV_DHCP_NO; 582 583 udphdr = (struct udphdr *)(skb->data + *header_len); 584 *header_len += sizeof(*udphdr); 585 586 /* check for bootp port */ 587 switch (proto) { 588 case htons(ETH_P_IP): 589 if (udphdr->dest == htons(67)) 590 ret = BATADV_DHCP_TO_SERVER; 591 else if (udphdr->source == htons(67)) 592 ret = BATADV_DHCP_TO_CLIENT; 593 break; 594 case htons(ETH_P_IPV6): 595 if (udphdr->dest == htons(547)) 596 ret = BATADV_DHCP_TO_SERVER; 597 else if (udphdr->source == htons(547)) 598 ret = BATADV_DHCP_TO_CLIENT; 599 break; 600 } 601 602 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; 603 /* store the client address if the message is going to a client */ 604 if (ret == BATADV_DHCP_TO_CLIENT && 605 pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { 606 /* check if the DHCP packet carries an Ethernet DHCP */ 607 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; 608 if (*p != BATADV_DHCP_HTYPE_ETHERNET) 609 return BATADV_DHCP_NO; 610 611 /* check if the DHCP packet carries a valid Ethernet address */ 612 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET; 613 if (*p != ETH_ALEN) 614 return BATADV_DHCP_NO; 615 616 ether_addr_copy(chaddr, skb->data + chaddr_offset); 617 } 618 619 return ret; 620 } 621 622 /** 623 * batadv_gw_out_of_range - check if the dhcp request destination is the best gw 624 * @bat_priv: the bat priv with all the soft interface information 625 * @skb: the outgoing packet 626 * 627 * Check if the skb is a DHCP request and if it is sent to the current best GW 628 * server. Due to topology changes it may be the case that the GW server 629 * previously selected is not the best one anymore. 630 * 631 * This call might reallocate skb data. 632 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER. 633 * 634 * Return: true if the packet destination is unicast and it is not the best gw, 635 * false otherwise. 636 */ 637 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, 638 struct sk_buff *skb) 639 { 640 struct batadv_neigh_node *neigh_curr = NULL; 641 struct batadv_neigh_node *neigh_old = NULL; 642 struct batadv_orig_node *orig_dst_node = NULL; 643 struct batadv_gw_node *gw_node = NULL; 644 struct batadv_gw_node *curr_gw = NULL; 645 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; 646 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 647 bool out_of_range = false; 648 u8 curr_tq_avg; 649 unsigned short vid; 650 651 vid = batadv_get_vid(skb, 0); 652 653 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 654 ethhdr->h_dest, vid); 655 if (!orig_dst_node) 656 goto out; 657 658 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node); 659 if (!gw_node) 660 goto out; 661 662 switch (atomic_read(&bat_priv->gw.mode)) { 663 case BATADV_GW_MODE_SERVER: 664 /* If we are a GW then we are our best GW. We can artificially 665 * set the tq towards ourself as the maximum value 666 */ 667 curr_tq_avg = BATADV_TQ_MAX_VALUE; 668 break; 669 case BATADV_GW_MODE_CLIENT: 670 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 671 if (!curr_gw) 672 goto out; 673 674 /* packet is going to our gateway */ 675 if (curr_gw->orig_node == orig_dst_node) 676 goto out; 677 678 /* If the dhcp packet has been sent to a different gw, 679 * we have to evaluate whether the old gw is still 680 * reliable enough 681 */ 682 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node, 683 NULL); 684 if (!neigh_curr) 685 goto out; 686 687 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr, 688 BATADV_IF_DEFAULT); 689 if (!curr_ifinfo) 690 goto out; 691 692 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg; 693 batadv_neigh_ifinfo_put(curr_ifinfo); 694 695 break; 696 case BATADV_GW_MODE_OFF: 697 default: 698 goto out; 699 } 700 701 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL); 702 if (!neigh_old) 703 goto out; 704 705 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT); 706 if (!old_ifinfo) 707 goto out; 708 709 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD) 710 out_of_range = true; 711 batadv_neigh_ifinfo_put(old_ifinfo); 712 713 out: 714 if (orig_dst_node) 715 batadv_orig_node_put(orig_dst_node); 716 if (curr_gw) 717 batadv_gw_node_put(curr_gw); 718 if (gw_node) 719 batadv_gw_node_put(gw_node); 720 if (neigh_old) 721 batadv_neigh_node_put(neigh_old); 722 if (neigh_curr) 723 batadv_neigh_node_put(neigh_curr); 724 return out_of_range; 725 } 726