1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (C) B.A.T.M.A.N. contributors: 3 * 4 * Marek Lindner 5 */ 6 7 #include "gateway_client.h" 8 #include "main.h" 9 10 #include <linux/atomic.h> 11 #include <linux/byteorder/generic.h> 12 #include <linux/errno.h> 13 #include <linux/etherdevice.h> 14 #include <linux/gfp.h> 15 #include <linux/if_ether.h> 16 #include <linux/if_vlan.h> 17 #include <linux/in.h> 18 #include <linux/ip.h> 19 #include <linux/ipv6.h> 20 #include <linux/kernel.h> 21 #include <linux/kref.h> 22 #include <linux/list.h> 23 #include <linux/lockdep.h> 24 #include <linux/netdevice.h> 25 #include <linux/netlink.h> 26 #include <linux/rculist.h> 27 #include <linux/rcupdate.h> 28 #include <linux/skbuff.h> 29 #include <linux/slab.h> 30 #include <linux/spinlock.h> 31 #include <linux/stddef.h> 32 #include <linux/udp.h> 33 #include <net/sock.h> 34 #include <uapi/linux/batadv_packet.h> 35 #include <uapi/linux/batman_adv.h> 36 37 #include "hard-interface.h" 38 #include "log.h" 39 #include "netlink.h" 40 #include "originator.h" 41 #include "routing.h" 42 #include "soft-interface.h" 43 #include "translation-table.h" 44 45 /* These are the offsets of the "hw type" and "hw address length" in the dhcp 46 * packet starting at the beginning of the dhcp header 47 */ 48 #define BATADV_DHCP_HTYPE_OFFSET 1 49 #define BATADV_DHCP_HLEN_OFFSET 2 50 /* Value of htype representing Ethernet */ 51 #define BATADV_DHCP_HTYPE_ETHERNET 0x01 52 /* This is the offset of the "chaddr" field in the dhcp packet starting at the 53 * beginning of the dhcp header 54 */ 55 #define BATADV_DHCP_CHADDR_OFFSET 28 56 57 /** 58 * batadv_gw_node_release() - release gw_node from lists and queue for free 59 * after rcu grace period 60 * @ref: kref pointer of the gw_node 61 */ 62 void batadv_gw_node_release(struct kref *ref) 63 { 64 struct batadv_gw_node *gw_node; 65 66 gw_node = container_of(ref, struct batadv_gw_node, refcount); 67 68 batadv_orig_node_put(gw_node->orig_node); 69 kfree_rcu(gw_node, rcu); 70 } 71 72 /** 73 * batadv_gw_get_selected_gw_node() - Get currently selected gateway 74 * @bat_priv: the bat priv with all the soft interface information 75 * 76 * Return: selected gateway (with increased refcnt), NULL on errors 77 */ 78 struct batadv_gw_node * 79 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv) 80 { 81 struct batadv_gw_node *gw_node; 82 83 rcu_read_lock(); 84 gw_node = rcu_dereference(bat_priv->gw.curr_gw); 85 if (!gw_node) 86 goto out; 87 88 if (!kref_get_unless_zero(&gw_node->refcount)) 89 gw_node = NULL; 90 91 out: 92 rcu_read_unlock(); 93 return gw_node; 94 } 95 96 /** 97 * batadv_gw_get_selected_orig() - Get originator of currently selected gateway 98 * @bat_priv: the bat priv with all the soft interface information 99 * 100 * Return: orig_node of selected gateway (with increased refcnt), NULL on errors 101 */ 102 struct batadv_orig_node * 103 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv) 104 { 105 struct batadv_gw_node *gw_node; 106 struct batadv_orig_node *orig_node = NULL; 107 108 gw_node = batadv_gw_get_selected_gw_node(bat_priv); 109 if (!gw_node) 110 goto out; 111 112 rcu_read_lock(); 113 orig_node = gw_node->orig_node; 114 if (!orig_node) 115 goto unlock; 116 117 if (!kref_get_unless_zero(&orig_node->refcount)) 118 orig_node = NULL; 119 120 unlock: 121 rcu_read_unlock(); 122 out: 123 batadv_gw_node_put(gw_node); 124 return orig_node; 125 } 126 127 static void batadv_gw_select(struct batadv_priv *bat_priv, 128 struct batadv_gw_node *new_gw_node) 129 { 130 struct batadv_gw_node *curr_gw_node; 131 132 spin_lock_bh(&bat_priv->gw.list_lock); 133 134 if (new_gw_node) 135 kref_get(&new_gw_node->refcount); 136 137 curr_gw_node = rcu_replace_pointer(bat_priv->gw.curr_gw, new_gw_node, 138 true); 139 140 batadv_gw_node_put(curr_gw_node); 141 142 spin_unlock_bh(&bat_priv->gw.list_lock); 143 } 144 145 /** 146 * batadv_gw_reselect() - force a gateway reselection 147 * @bat_priv: the bat priv with all the soft interface information 148 * 149 * Set a flag to remind the GW component to perform a new gateway reselection. 150 * However this function does not ensure that the current gateway is going to be 151 * deselected. The reselection mechanism may elect the same gateway once again. 152 * 153 * This means that invoking batadv_gw_reselect() does not guarantee a gateway 154 * change and therefore a uevent is not necessarily expected. 155 */ 156 void batadv_gw_reselect(struct batadv_priv *bat_priv) 157 { 158 atomic_set(&bat_priv->gw.reselect, 1); 159 } 160 161 /** 162 * batadv_gw_check_client_stop() - check if client mode has been switched off 163 * @bat_priv: the bat priv with all the soft interface information 164 * 165 * This function assumes the caller has checked that the gw state *is actually 166 * changing*. This function is not supposed to be called when there is no state 167 * change. 168 */ 169 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv) 170 { 171 struct batadv_gw_node *curr_gw; 172 173 if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT) 174 return; 175 176 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 177 if (!curr_gw) 178 return; 179 180 /* deselect the current gateway so that next time that client mode is 181 * enabled a proper GW_ADD event can be sent 182 */ 183 batadv_gw_select(bat_priv, NULL); 184 185 /* if batman-adv is switching the gw client mode off and a gateway was 186 * already selected, send a DEL uevent 187 */ 188 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL); 189 190 batadv_gw_node_put(curr_gw); 191 } 192 193 /** 194 * batadv_gw_election() - Elect the best gateway 195 * @bat_priv: the bat priv with all the soft interface information 196 */ 197 void batadv_gw_election(struct batadv_priv *bat_priv) 198 { 199 struct batadv_gw_node *curr_gw = NULL; 200 struct batadv_gw_node *next_gw = NULL; 201 struct batadv_neigh_node *router = NULL; 202 struct batadv_neigh_ifinfo *router_ifinfo = NULL; 203 char gw_addr[18] = { '\0' }; 204 205 if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT) 206 goto out; 207 208 if (!bat_priv->algo_ops->gw.get_best_gw_node) 209 goto out; 210 211 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 212 213 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw) 214 goto out; 215 216 /* if gw.reselect is set to 1 it means that a previous call to 217 * gw.is_eligible() said that we have a new best GW, therefore it can 218 * now be picked from the list and selected 219 */ 220 next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv); 221 222 if (curr_gw == next_gw) 223 goto out; 224 225 if (next_gw) { 226 sprintf(gw_addr, "%pM", next_gw->orig_node->orig); 227 228 router = batadv_orig_router_get(next_gw->orig_node, 229 BATADV_IF_DEFAULT); 230 if (!router) { 231 batadv_gw_reselect(bat_priv); 232 goto out; 233 } 234 235 router_ifinfo = batadv_neigh_ifinfo_get(router, 236 BATADV_IF_DEFAULT); 237 if (!router_ifinfo) { 238 batadv_gw_reselect(bat_priv); 239 goto out; 240 } 241 } 242 243 if (curr_gw && !next_gw) { 244 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 245 "Removing selected gateway - no gateway in range\n"); 246 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, 247 NULL); 248 } else if (!curr_gw && next_gw) { 249 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 250 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 251 next_gw->orig_node->orig, 252 next_gw->bandwidth_down / 10, 253 next_gw->bandwidth_down % 10, 254 next_gw->bandwidth_up / 10, 255 next_gw->bandwidth_up % 10, 256 router_ifinfo->bat_iv.tq_avg); 257 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD, 258 gw_addr); 259 } else { 260 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 261 "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n", 262 next_gw->orig_node->orig, 263 next_gw->bandwidth_down / 10, 264 next_gw->bandwidth_down % 10, 265 next_gw->bandwidth_up / 10, 266 next_gw->bandwidth_up % 10, 267 router_ifinfo->bat_iv.tq_avg); 268 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE, 269 gw_addr); 270 } 271 272 batadv_gw_select(bat_priv, next_gw); 273 274 out: 275 batadv_gw_node_put(curr_gw); 276 batadv_gw_node_put(next_gw); 277 batadv_neigh_node_put(router); 278 batadv_neigh_ifinfo_put(router_ifinfo); 279 } 280 281 /** 282 * batadv_gw_check_election() - Elect orig node as best gateway when eligible 283 * @bat_priv: the bat priv with all the soft interface information 284 * @orig_node: orig node which is to be checked 285 */ 286 void batadv_gw_check_election(struct batadv_priv *bat_priv, 287 struct batadv_orig_node *orig_node) 288 { 289 struct batadv_orig_node *curr_gw_orig; 290 291 /* abort immediately if the routing algorithm does not support gateway 292 * election 293 */ 294 if (!bat_priv->algo_ops->gw.is_eligible) 295 return; 296 297 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv); 298 if (!curr_gw_orig) 299 goto reselect; 300 301 /* this node already is the gateway */ 302 if (curr_gw_orig == orig_node) 303 goto out; 304 305 if (!bat_priv->algo_ops->gw.is_eligible(bat_priv, curr_gw_orig, 306 orig_node)) 307 goto out; 308 309 reselect: 310 batadv_gw_reselect(bat_priv); 311 out: 312 batadv_orig_node_put(curr_gw_orig); 313 } 314 315 /** 316 * batadv_gw_node_add() - add gateway node to list of available gateways 317 * @bat_priv: the bat priv with all the soft interface information 318 * @orig_node: originator announcing gateway capabilities 319 * @gateway: announced bandwidth information 320 * 321 * Has to be called with the appropriate locks being acquired 322 * (gw.list_lock). 323 */ 324 static void batadv_gw_node_add(struct batadv_priv *bat_priv, 325 struct batadv_orig_node *orig_node, 326 struct batadv_tvlv_gateway_data *gateway) 327 { 328 struct batadv_gw_node *gw_node; 329 330 lockdep_assert_held(&bat_priv->gw.list_lock); 331 332 if (gateway->bandwidth_down == 0) 333 return; 334 335 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC); 336 if (!gw_node) 337 return; 338 339 kref_init(&gw_node->refcount); 340 INIT_HLIST_NODE(&gw_node->list); 341 kref_get(&orig_node->refcount); 342 gw_node->orig_node = orig_node; 343 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 344 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 345 346 kref_get(&gw_node->refcount); 347 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.gateway_list); 348 bat_priv->gw.generation++; 349 350 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 351 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", 352 orig_node->orig, 353 ntohl(gateway->bandwidth_down) / 10, 354 ntohl(gateway->bandwidth_down) % 10, 355 ntohl(gateway->bandwidth_up) / 10, 356 ntohl(gateway->bandwidth_up) % 10); 357 358 /* don't return reference to new gw_node */ 359 batadv_gw_node_put(gw_node); 360 } 361 362 /** 363 * batadv_gw_node_get() - retrieve gateway node from list of available gateways 364 * @bat_priv: the bat priv with all the soft interface information 365 * @orig_node: originator announcing gateway capabilities 366 * 367 * Return: gateway node if found or NULL otherwise. 368 */ 369 struct batadv_gw_node *batadv_gw_node_get(struct batadv_priv *bat_priv, 370 struct batadv_orig_node *orig_node) 371 { 372 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL; 373 374 rcu_read_lock(); 375 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.gateway_list, 376 list) { 377 if (gw_node_tmp->orig_node != orig_node) 378 continue; 379 380 if (!kref_get_unless_zero(&gw_node_tmp->refcount)) 381 continue; 382 383 gw_node = gw_node_tmp; 384 break; 385 } 386 rcu_read_unlock(); 387 388 return gw_node; 389 } 390 391 /** 392 * batadv_gw_node_update() - update list of available gateways with changed 393 * bandwidth information 394 * @bat_priv: the bat priv with all the soft interface information 395 * @orig_node: originator announcing gateway capabilities 396 * @gateway: announced bandwidth information 397 */ 398 void batadv_gw_node_update(struct batadv_priv *bat_priv, 399 struct batadv_orig_node *orig_node, 400 struct batadv_tvlv_gateway_data *gateway) 401 { 402 struct batadv_gw_node *gw_node, *curr_gw = NULL; 403 404 spin_lock_bh(&bat_priv->gw.list_lock); 405 gw_node = batadv_gw_node_get(bat_priv, orig_node); 406 if (!gw_node) { 407 batadv_gw_node_add(bat_priv, orig_node, gateway); 408 spin_unlock_bh(&bat_priv->gw.list_lock); 409 goto out; 410 } 411 spin_unlock_bh(&bat_priv->gw.list_lock); 412 413 if (gw_node->bandwidth_down == ntohl(gateway->bandwidth_down) && 414 gw_node->bandwidth_up == ntohl(gateway->bandwidth_up)) 415 goto out; 416 417 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 418 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n", 419 orig_node->orig, 420 gw_node->bandwidth_down / 10, 421 gw_node->bandwidth_down % 10, 422 gw_node->bandwidth_up / 10, 423 gw_node->bandwidth_up % 10, 424 ntohl(gateway->bandwidth_down) / 10, 425 ntohl(gateway->bandwidth_down) % 10, 426 ntohl(gateway->bandwidth_up) / 10, 427 ntohl(gateway->bandwidth_up) % 10); 428 429 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down); 430 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up); 431 432 if (ntohl(gateway->bandwidth_down) == 0) { 433 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, 434 "Gateway %pM removed from gateway list\n", 435 orig_node->orig); 436 437 /* Note: We don't need a NULL check here, since curr_gw never 438 * gets dereferenced. 439 */ 440 spin_lock_bh(&bat_priv->gw.list_lock); 441 if (!hlist_unhashed(&gw_node->list)) { 442 hlist_del_init_rcu(&gw_node->list); 443 batadv_gw_node_put(gw_node); 444 bat_priv->gw.generation++; 445 } 446 spin_unlock_bh(&bat_priv->gw.list_lock); 447 448 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 449 if (gw_node == curr_gw) 450 batadv_gw_reselect(bat_priv); 451 452 batadv_gw_node_put(curr_gw); 453 } 454 455 out: 456 batadv_gw_node_put(gw_node); 457 } 458 459 /** 460 * batadv_gw_node_delete() - Remove orig_node from gateway list 461 * @bat_priv: the bat priv with all the soft interface information 462 * @orig_node: orig node which is currently in process of being removed 463 */ 464 void batadv_gw_node_delete(struct batadv_priv *bat_priv, 465 struct batadv_orig_node *orig_node) 466 { 467 struct batadv_tvlv_gateway_data gateway; 468 469 gateway.bandwidth_down = 0; 470 gateway.bandwidth_up = 0; 471 472 batadv_gw_node_update(bat_priv, orig_node, &gateway); 473 } 474 475 /** 476 * batadv_gw_node_free() - Free gateway information from soft interface 477 * @bat_priv: the bat priv with all the soft interface information 478 */ 479 void batadv_gw_node_free(struct batadv_priv *bat_priv) 480 { 481 struct batadv_gw_node *gw_node; 482 struct hlist_node *node_tmp; 483 484 spin_lock_bh(&bat_priv->gw.list_lock); 485 hlist_for_each_entry_safe(gw_node, node_tmp, 486 &bat_priv->gw.gateway_list, list) { 487 hlist_del_init_rcu(&gw_node->list); 488 batadv_gw_node_put(gw_node); 489 bat_priv->gw.generation++; 490 } 491 spin_unlock_bh(&bat_priv->gw.list_lock); 492 } 493 494 /** 495 * batadv_gw_dump() - Dump gateways into a message 496 * @msg: Netlink message to dump into 497 * @cb: Control block containing additional options 498 * 499 * Return: Error code, or length of message 500 */ 501 int batadv_gw_dump(struct sk_buff *msg, struct netlink_callback *cb) 502 { 503 struct batadv_hard_iface *primary_if = NULL; 504 struct net *net = sock_net(cb->skb->sk); 505 struct net_device *soft_iface; 506 struct batadv_priv *bat_priv; 507 int ifindex; 508 int ret; 509 510 ifindex = batadv_netlink_get_ifindex(cb->nlh, 511 BATADV_ATTR_MESH_IFINDEX); 512 if (!ifindex) 513 return -EINVAL; 514 515 soft_iface = dev_get_by_index(net, ifindex); 516 if (!soft_iface || !batadv_softif_is_valid(soft_iface)) { 517 ret = -ENODEV; 518 goto out; 519 } 520 521 bat_priv = netdev_priv(soft_iface); 522 523 primary_if = batadv_primary_if_get_selected(bat_priv); 524 if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) { 525 ret = -ENOENT; 526 goto out; 527 } 528 529 if (!bat_priv->algo_ops->gw.dump) { 530 ret = -EOPNOTSUPP; 531 goto out; 532 } 533 534 bat_priv->algo_ops->gw.dump(msg, cb, bat_priv); 535 536 ret = msg->len; 537 538 out: 539 batadv_hardif_put(primary_if); 540 dev_put(soft_iface); 541 542 return ret; 543 } 544 545 /** 546 * batadv_gw_dhcp_recipient_get() - check if a packet is a DHCP message 547 * @skb: the packet to check 548 * @header_len: a pointer to the batman-adv header size 549 * @chaddr: buffer where the client address will be stored. Valid 550 * only if the function returns BATADV_DHCP_TO_CLIENT 551 * 552 * This function may re-allocate the data buffer of the skb passed as argument. 553 * 554 * Return: 555 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error 556 * while parsing it 557 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server 558 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client 559 */ 560 enum batadv_dhcp_recipient 561 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, 562 u8 *chaddr) 563 { 564 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO; 565 struct ethhdr *ethhdr; 566 struct iphdr *iphdr; 567 struct ipv6hdr *ipv6hdr; 568 struct udphdr *udphdr; 569 struct vlan_ethhdr *vhdr; 570 int chaddr_offset; 571 __be16 proto; 572 u8 *p; 573 574 /* check for ethernet header */ 575 if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) 576 return BATADV_DHCP_NO; 577 578 ethhdr = eth_hdr(skb); 579 proto = ethhdr->h_proto; 580 *header_len += ETH_HLEN; 581 582 /* check for initial vlan header */ 583 if (proto == htons(ETH_P_8021Q)) { 584 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) 585 return BATADV_DHCP_NO; 586 587 vhdr = vlan_eth_hdr(skb); 588 proto = vhdr->h_vlan_encapsulated_proto; 589 *header_len += VLAN_HLEN; 590 } 591 592 /* check for ip header */ 593 switch (proto) { 594 case htons(ETH_P_IP): 595 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) 596 return BATADV_DHCP_NO; 597 598 iphdr = (struct iphdr *)(skb->data + *header_len); 599 *header_len += iphdr->ihl * 4; 600 601 /* check for udp header */ 602 if (iphdr->protocol != IPPROTO_UDP) 603 return BATADV_DHCP_NO; 604 605 break; 606 case htons(ETH_P_IPV6): 607 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) 608 return BATADV_DHCP_NO; 609 610 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); 611 *header_len += sizeof(*ipv6hdr); 612 613 /* check for udp header */ 614 if (ipv6hdr->nexthdr != IPPROTO_UDP) 615 return BATADV_DHCP_NO; 616 617 break; 618 default: 619 return BATADV_DHCP_NO; 620 } 621 622 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) 623 return BATADV_DHCP_NO; 624 625 udphdr = (struct udphdr *)(skb->data + *header_len); 626 *header_len += sizeof(*udphdr); 627 628 /* check for bootp port */ 629 switch (proto) { 630 case htons(ETH_P_IP): 631 if (udphdr->dest == htons(67)) 632 ret = BATADV_DHCP_TO_SERVER; 633 else if (udphdr->source == htons(67)) 634 ret = BATADV_DHCP_TO_CLIENT; 635 break; 636 case htons(ETH_P_IPV6): 637 if (udphdr->dest == htons(547)) 638 ret = BATADV_DHCP_TO_SERVER; 639 else if (udphdr->source == htons(547)) 640 ret = BATADV_DHCP_TO_CLIENT; 641 break; 642 } 643 644 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; 645 /* store the client address if the message is going to a client */ 646 if (ret == BATADV_DHCP_TO_CLIENT) { 647 if (!pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) 648 return BATADV_DHCP_NO; 649 650 /* check if the DHCP packet carries an Ethernet DHCP */ 651 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; 652 if (*p != BATADV_DHCP_HTYPE_ETHERNET) 653 return BATADV_DHCP_NO; 654 655 /* check if the DHCP packet carries a valid Ethernet address */ 656 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET; 657 if (*p != ETH_ALEN) 658 return BATADV_DHCP_NO; 659 660 ether_addr_copy(chaddr, skb->data + chaddr_offset); 661 } 662 663 return ret; 664 } 665 666 /** 667 * batadv_gw_out_of_range() - check if the dhcp request destination is the best 668 * gateway 669 * @bat_priv: the bat priv with all the soft interface information 670 * @skb: the outgoing packet 671 * 672 * Check if the skb is a DHCP request and if it is sent to the current best GW 673 * server. Due to topology changes it may be the case that the GW server 674 * previously selected is not the best one anymore. 675 * 676 * This call might reallocate skb data. 677 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER. 678 * 679 * Return: true if the packet destination is unicast and it is not the best gw, 680 * false otherwise. 681 */ 682 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, 683 struct sk_buff *skb) 684 { 685 struct batadv_neigh_node *neigh_curr = NULL; 686 struct batadv_neigh_node *neigh_old = NULL; 687 struct batadv_orig_node *orig_dst_node = NULL; 688 struct batadv_gw_node *gw_node = NULL; 689 struct batadv_gw_node *curr_gw = NULL; 690 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; 691 struct ethhdr *ethhdr = (struct ethhdr *)skb->data; 692 bool out_of_range = false; 693 u8 curr_tq_avg; 694 unsigned short vid; 695 696 vid = batadv_get_vid(skb, 0); 697 698 if (is_multicast_ether_addr(ethhdr->h_dest)) 699 goto out; 700 701 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, 702 ethhdr->h_dest, vid); 703 if (!orig_dst_node) 704 goto out; 705 706 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node); 707 if (!gw_node) 708 goto out; 709 710 switch (atomic_read(&bat_priv->gw.mode)) { 711 case BATADV_GW_MODE_SERVER: 712 /* If we are a GW then we are our best GW. We can artificially 713 * set the tq towards ourself as the maximum value 714 */ 715 curr_tq_avg = BATADV_TQ_MAX_VALUE; 716 break; 717 case BATADV_GW_MODE_CLIENT: 718 curr_gw = batadv_gw_get_selected_gw_node(bat_priv); 719 if (!curr_gw) 720 goto out; 721 722 /* packet is going to our gateway */ 723 if (curr_gw->orig_node == orig_dst_node) 724 goto out; 725 726 /* If the dhcp packet has been sent to a different gw, 727 * we have to evaluate whether the old gw is still 728 * reliable enough 729 */ 730 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node, 731 NULL); 732 if (!neigh_curr) 733 goto out; 734 735 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr, 736 BATADV_IF_DEFAULT); 737 if (!curr_ifinfo) 738 goto out; 739 740 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg; 741 batadv_neigh_ifinfo_put(curr_ifinfo); 742 743 break; 744 case BATADV_GW_MODE_OFF: 745 default: 746 goto out; 747 } 748 749 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL); 750 if (!neigh_old) 751 goto out; 752 753 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT); 754 if (!old_ifinfo) 755 goto out; 756 757 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD) 758 out_of_range = true; 759 batadv_neigh_ifinfo_put(old_ifinfo); 760 761 out: 762 batadv_orig_node_put(orig_dst_node); 763 batadv_gw_node_put(curr_gw); 764 batadv_gw_node_put(gw_node); 765 batadv_neigh_node_put(neigh_old); 766 batadv_neigh_node_put(neigh_curr); 767 return out_of_range; 768 } 769