1 /* Copyright (C) 2009-2015 B.A.T.M.A.N. contributors:
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.
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.
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/>.
18 #include "gateway_client.h"
21 #include <linux/atomic.h>
22 #include <linux/byteorder/generic.h>
23 #include <linux/etherdevice.h>
25 #include <linux/if_ether.h>
26 #include <linux/if_vlan.h>
29 #include <linux/ipv6.h>
30 #include <linux/kernel.h>
31 #include <linux/list.h>
32 #include <linux/lockdep.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>
43 #include "gateway_common.h"
44 #include "hard-interface.h"
45 #include "originator.h"
49 #include "translation-table.h"
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
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
61 #define BATADV_DHCP_CHADDR_OFFSET 28
63 static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
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);
71 static struct batadv_gw_node *
72 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
74 struct batadv_gw_node *gw_node;
77 gw_node = rcu_dereference(bat_priv->gw.curr_gw);
81 if (!atomic_inc_not_zero(&gw_node->refcount))
89 struct batadv_orig_node *
90 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
92 struct batadv_gw_node *gw_node;
93 struct batadv_orig_node *orig_node = NULL;
95 gw_node = batadv_gw_get_selected_gw_node(bat_priv);
100 orig_node = gw_node->orig_node;
104 if (!atomic_inc_not_zero(&orig_node->refcount))
111 batadv_gw_node_free_ref(gw_node);
115 static void batadv_gw_select(struct batadv_priv *bat_priv,
116 struct batadv_gw_node *new_gw_node)
118 struct batadv_gw_node *curr_gw_node;
120 spin_lock_bh(&bat_priv->gw.list_lock);
122 if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
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);
129 batadv_gw_node_free_ref(curr_gw_node);
131 spin_unlock_bh(&bat_priv->gw.list_lock);
135 * batadv_gw_reselect - force a gateway reselection
136 * @bat_priv: the bat priv with all the soft interface information
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.
142 * This means that invoking batadv_gw_reselect() does not guarantee a gateway
143 * change and therefore a uevent is not necessarily expected.
145 void batadv_gw_reselect(struct batadv_priv *bat_priv)
147 atomic_set(&bat_priv->gw.reselect, 1);
150 static struct batadv_gw_node *
151 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
153 struct batadv_neigh_node *router;
154 struct batadv_neigh_ifinfo *router_ifinfo;
155 struct batadv_gw_node *gw_node, *curr_gw = NULL;
156 u64 max_gw_factor = 0;
157 u64 tmp_gw_factor = 0;
160 struct batadv_orig_node *orig_node;
163 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
164 orig_node = gw_node->orig_node;
165 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
169 router_ifinfo = batadv_neigh_ifinfo_get(router,
174 if (!atomic_inc_not_zero(&gw_node->refcount))
177 tq_avg = router_ifinfo->bat_iv.tq_avg;
179 switch (atomic_read(&bat_priv->gw_sel_class)) {
180 case 1: /* fast connection */
181 tmp_gw_factor = tq_avg * tq_avg;
182 tmp_gw_factor *= gw_node->bandwidth_down;
183 tmp_gw_factor *= 100 * 100;
184 tmp_gw_factor >>= 18;
186 if ((tmp_gw_factor > max_gw_factor) ||
187 ((tmp_gw_factor == max_gw_factor) &&
188 (tq_avg > max_tq))) {
190 batadv_gw_node_free_ref(curr_gw);
192 atomic_inc(&curr_gw->refcount);
196 default: /* 2: stable connection (use best statistic)
197 * 3: fast-switch (use best statistic but change as
198 * soon as a better gateway appears)
199 * XX: late-switch (use best statistic but change as
200 * soon as a better gateway appears which has
201 * $routing_class more tq points)
203 if (tq_avg > max_tq) {
205 batadv_gw_node_free_ref(curr_gw);
207 atomic_inc(&curr_gw->refcount);
215 if (tmp_gw_factor > max_gw_factor)
216 max_gw_factor = tmp_gw_factor;
218 batadv_gw_node_free_ref(gw_node);
221 batadv_neigh_node_free_ref(router);
223 batadv_neigh_ifinfo_free_ref(router_ifinfo);
231 * batadv_gw_check_client_stop - check if client mode has been switched off
232 * @bat_priv: the bat priv with all the soft interface information
234 * This function assumes the caller has checked that the gw state *is actually
235 * changing*. This function is not supposed to be called when there is no state
238 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
240 struct batadv_gw_node *curr_gw;
242 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
245 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
249 /* deselect the current gateway so that next time that client mode is
250 * enabled a proper GW_ADD event can be sent
252 batadv_gw_select(bat_priv, NULL);
254 /* if batman-adv is switching the gw client mode off and a gateway was
255 * already selected, send a DEL uevent
257 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
259 batadv_gw_node_free_ref(curr_gw);
262 void batadv_gw_election(struct batadv_priv *bat_priv)
264 struct batadv_gw_node *curr_gw = NULL;
265 struct batadv_gw_node *next_gw = NULL;
266 struct batadv_neigh_node *router = NULL;
267 struct batadv_neigh_ifinfo *router_ifinfo = NULL;
268 char gw_addr[18] = { '\0' };
270 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
273 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
275 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
278 next_gw = batadv_gw_get_best_gw_node(bat_priv);
280 if (curr_gw == next_gw)
284 sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
286 router = batadv_orig_router_get(next_gw->orig_node,
289 batadv_gw_reselect(bat_priv);
293 router_ifinfo = batadv_neigh_ifinfo_get(router,
295 if (!router_ifinfo) {
296 batadv_gw_reselect(bat_priv);
301 if ((curr_gw) && (!next_gw)) {
302 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
303 "Removing selected gateway - no gateway in range\n");
304 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
306 } else if ((!curr_gw) && (next_gw)) {
307 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
308 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
309 next_gw->orig_node->orig,
310 next_gw->bandwidth_down / 10,
311 next_gw->bandwidth_down % 10,
312 next_gw->bandwidth_up / 10,
313 next_gw->bandwidth_up % 10,
314 router_ifinfo->bat_iv.tq_avg);
315 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
318 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
319 "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
320 next_gw->orig_node->orig,
321 next_gw->bandwidth_down / 10,
322 next_gw->bandwidth_down % 10,
323 next_gw->bandwidth_up / 10,
324 next_gw->bandwidth_up % 10,
325 router_ifinfo->bat_iv.tq_avg);
326 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
330 batadv_gw_select(bat_priv, next_gw);
334 batadv_gw_node_free_ref(curr_gw);
336 batadv_gw_node_free_ref(next_gw);
338 batadv_neigh_node_free_ref(router);
340 batadv_neigh_ifinfo_free_ref(router_ifinfo);
343 void batadv_gw_check_election(struct batadv_priv *bat_priv,
344 struct batadv_orig_node *orig_node)
346 struct batadv_neigh_ifinfo *router_orig_tq = NULL;
347 struct batadv_neigh_ifinfo *router_gw_tq = NULL;
348 struct batadv_orig_node *curr_gw_orig;
349 struct batadv_neigh_node *router_gw = NULL;
350 struct batadv_neigh_node *router_orig = NULL;
351 u8 gw_tq_avg, orig_tq_avg;
353 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
357 router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
361 router_gw_tq = batadv_neigh_ifinfo_get(router_gw,
366 /* this node already is the gateway */
367 if (curr_gw_orig == orig_node)
370 router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
374 router_orig_tq = batadv_neigh_ifinfo_get(router_orig,
379 gw_tq_avg = router_gw_tq->bat_iv.tq_avg;
380 orig_tq_avg = router_orig_tq->bat_iv.tq_avg;
382 /* the TQ value has to be better */
383 if (orig_tq_avg < gw_tq_avg)
386 /* if the routing class is greater than 3 the value tells us how much
387 * greater the TQ value of the new gateway must be
389 if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
390 (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
393 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
394 "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
395 gw_tq_avg, orig_tq_avg);
398 batadv_gw_reselect(bat_priv);
401 batadv_orig_node_free_ref(curr_gw_orig);
403 batadv_neigh_node_free_ref(router_gw);
405 batadv_neigh_node_free_ref(router_orig);
407 batadv_neigh_ifinfo_free_ref(router_gw_tq);
409 batadv_neigh_ifinfo_free_ref(router_orig_tq);
413 * batadv_gw_node_add - add gateway node to list of available gateways
414 * @bat_priv: the bat priv with all the soft interface information
415 * @orig_node: originator announcing gateway capabilities
416 * @gateway: announced bandwidth information
418 * Has to be called with the appropriate locks being acquired
421 static void batadv_gw_node_add(struct batadv_priv *bat_priv,
422 struct batadv_orig_node *orig_node,
423 struct batadv_tvlv_gateway_data *gateway)
425 struct batadv_gw_node *gw_node;
427 lockdep_assert_held(&bat_priv->gw.list_lock);
429 if (gateway->bandwidth_down == 0)
432 if (!atomic_inc_not_zero(&orig_node->refcount))
435 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
437 batadv_orig_node_free_ref(orig_node);
441 INIT_HLIST_NODE(&gw_node->list);
442 gw_node->orig_node = orig_node;
443 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
444 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
445 atomic_set(&gw_node->refcount, 1);
447 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list);
449 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
450 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
452 ntohl(gateway->bandwidth_down) / 10,
453 ntohl(gateway->bandwidth_down) % 10,
454 ntohl(gateway->bandwidth_up) / 10,
455 ntohl(gateway->bandwidth_up) % 10);
459 * batadv_gw_node_get - retrieve gateway node from list of available gateways
460 * @bat_priv: the bat priv with all the soft interface information
461 * @orig_node: originator announcing gateway capabilities
463 * Returns gateway node if found or NULL otherwise.
465 static struct batadv_gw_node *
466 batadv_gw_node_get(struct batadv_priv *bat_priv,
467 struct batadv_orig_node *orig_node)
469 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
472 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) {
473 if (gw_node_tmp->orig_node != orig_node)
476 if (!atomic_inc_not_zero(&gw_node_tmp->refcount))
479 gw_node = gw_node_tmp;
488 * batadv_gw_node_update - update list of available gateways with changed
489 * bandwidth information
490 * @bat_priv: the bat priv with all the soft interface information
491 * @orig_node: originator announcing gateway capabilities
492 * @gateway: announced bandwidth information
494 void batadv_gw_node_update(struct batadv_priv *bat_priv,
495 struct batadv_orig_node *orig_node,
496 struct batadv_tvlv_gateway_data *gateway)
498 struct batadv_gw_node *gw_node, *curr_gw = NULL;
500 spin_lock_bh(&bat_priv->gw.list_lock);
501 gw_node = batadv_gw_node_get(bat_priv, orig_node);
503 batadv_gw_node_add(bat_priv, orig_node, gateway);
504 spin_unlock_bh(&bat_priv->gw.list_lock);
507 spin_unlock_bh(&bat_priv->gw.list_lock);
509 if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) &&
510 (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up)))
513 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
514 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
516 gw_node->bandwidth_down / 10,
517 gw_node->bandwidth_down % 10,
518 gw_node->bandwidth_up / 10,
519 gw_node->bandwidth_up % 10,
520 ntohl(gateway->bandwidth_down) / 10,
521 ntohl(gateway->bandwidth_down) % 10,
522 ntohl(gateway->bandwidth_up) / 10,
523 ntohl(gateway->bandwidth_up) % 10);
525 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
526 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
528 if (ntohl(gateway->bandwidth_down) == 0) {
529 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
530 "Gateway %pM removed from gateway list\n",
533 /* Note: We don't need a NULL check here, since curr_gw never
536 spin_lock_bh(&bat_priv->gw.list_lock);
537 if (!hlist_unhashed(&gw_node->list)) {
538 hlist_del_init_rcu(&gw_node->list);
539 batadv_gw_node_free_ref(gw_node);
541 spin_unlock_bh(&bat_priv->gw.list_lock);
543 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
544 if (gw_node == curr_gw)
545 batadv_gw_reselect(bat_priv);
548 batadv_gw_node_free_ref(curr_gw);
553 batadv_gw_node_free_ref(gw_node);
556 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
557 struct batadv_orig_node *orig_node)
559 struct batadv_tvlv_gateway_data gateway;
561 gateway.bandwidth_down = 0;
562 gateway.bandwidth_up = 0;
564 batadv_gw_node_update(bat_priv, orig_node, &gateway);
567 void batadv_gw_node_free(struct batadv_priv *bat_priv)
569 struct batadv_gw_node *gw_node;
570 struct hlist_node *node_tmp;
572 spin_lock_bh(&bat_priv->gw.list_lock);
573 hlist_for_each_entry_safe(gw_node, node_tmp,
574 &bat_priv->gw.list, list) {
575 hlist_del_init_rcu(&gw_node->list);
576 batadv_gw_node_free_ref(gw_node);
578 spin_unlock_bh(&bat_priv->gw.list_lock);
581 /* fails if orig_node has no router */
582 static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
583 struct seq_file *seq,
584 const struct batadv_gw_node *gw_node)
586 struct batadv_gw_node *curr_gw;
587 struct batadv_neigh_node *router;
588 struct batadv_neigh_ifinfo *router_ifinfo = NULL;
591 router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
595 router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
599 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
601 seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
602 (curr_gw == gw_node ? "=>" : " "),
603 gw_node->orig_node->orig,
604 router_ifinfo->bat_iv.tq_avg, router->addr,
605 router->if_incoming->net_dev->name,
606 gw_node->bandwidth_down / 10,
607 gw_node->bandwidth_down % 10,
608 gw_node->bandwidth_up / 10,
609 gw_node->bandwidth_up % 10);
610 ret = seq_has_overflowed(seq) ? -1 : 0;
613 batadv_gw_node_free_ref(curr_gw);
616 batadv_neigh_ifinfo_free_ref(router_ifinfo);
618 batadv_neigh_node_free_ref(router);
622 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
624 struct net_device *net_dev = (struct net_device *)seq->private;
625 struct batadv_priv *bat_priv = netdev_priv(net_dev);
626 struct batadv_hard_iface *primary_if;
627 struct batadv_gw_node *gw_node;
630 primary_if = batadv_seq_print_text_primary_if_get(seq);
635 " %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
636 "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
637 BATADV_SOURCE_VERSION, primary_if->net_dev->name,
638 primary_if->net_dev->dev_addr, net_dev->name);
641 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
642 /* fails if orig_node has no router */
643 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
651 seq_puts(seq, "No gateways in range ...\n");
655 batadv_hardif_free_ref(primary_if);
660 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message
661 * @skb: the packet to check
662 * @header_len: a pointer to the batman-adv header size
663 * @chaddr: buffer where the client address will be stored. Valid
664 * only if the function returns BATADV_DHCP_TO_CLIENT
667 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
669 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
670 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
672 * This function may re-allocate the data buffer of the skb passed as argument.
674 enum batadv_dhcp_recipient
675 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
678 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
679 struct ethhdr *ethhdr;
681 struct ipv6hdr *ipv6hdr;
682 struct udphdr *udphdr;
683 struct vlan_ethhdr *vhdr;
688 /* check for ethernet header */
689 if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
690 return BATADV_DHCP_NO;
692 ethhdr = eth_hdr(skb);
693 proto = ethhdr->h_proto;
694 *header_len += ETH_HLEN;
696 /* check for initial vlan header */
697 if (proto == htons(ETH_P_8021Q)) {
698 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
699 return BATADV_DHCP_NO;
701 vhdr = vlan_eth_hdr(skb);
702 proto = vhdr->h_vlan_encapsulated_proto;
703 *header_len += VLAN_HLEN;
706 /* check for ip header */
708 case htons(ETH_P_IP):
709 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
710 return BATADV_DHCP_NO;
712 iphdr = (struct iphdr *)(skb->data + *header_len);
713 *header_len += iphdr->ihl * 4;
715 /* check for udp header */
716 if (iphdr->protocol != IPPROTO_UDP)
717 return BATADV_DHCP_NO;
720 case htons(ETH_P_IPV6):
721 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
722 return BATADV_DHCP_NO;
724 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
725 *header_len += sizeof(*ipv6hdr);
727 /* check for udp header */
728 if (ipv6hdr->nexthdr != IPPROTO_UDP)
729 return BATADV_DHCP_NO;
733 return BATADV_DHCP_NO;
736 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
737 return BATADV_DHCP_NO;
739 udphdr = (struct udphdr *)(skb->data + *header_len);
740 *header_len += sizeof(*udphdr);
742 /* check for bootp port */
744 case htons(ETH_P_IP):
745 if (udphdr->dest == htons(67))
746 ret = BATADV_DHCP_TO_SERVER;
747 else if (udphdr->source == htons(67))
748 ret = BATADV_DHCP_TO_CLIENT;
750 case htons(ETH_P_IPV6):
751 if (udphdr->dest == htons(547))
752 ret = BATADV_DHCP_TO_SERVER;
753 else if (udphdr->source == htons(547))
754 ret = BATADV_DHCP_TO_CLIENT;
758 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
759 /* store the client address if the message is going to a client */
760 if (ret == BATADV_DHCP_TO_CLIENT) {
761 if (!pskb_may_pull(skb, chaddr_offset + ETH_ALEN))
762 return BATADV_DHCP_NO;
764 /* check if the DHCP packet carries an Ethernet DHCP */
765 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
766 if (*p != BATADV_DHCP_HTYPE_ETHERNET)
767 return BATADV_DHCP_NO;
769 /* check if the DHCP packet carries a valid Ethernet address */
770 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
772 return BATADV_DHCP_NO;
774 ether_addr_copy(chaddr, skb->data + chaddr_offset);
781 * batadv_gw_out_of_range - check if the dhcp request destination is the best gw
782 * @bat_priv: the bat priv with all the soft interface information
783 * @skb: the outgoing packet
785 * Check if the skb is a DHCP request and if it is sent to the current best GW
786 * server. Due to topology changes it may be the case that the GW server
787 * previously selected is not the best one anymore.
789 * Returns true if the packet destination is unicast and it is not the best gw,
792 * This call might reallocate skb data.
793 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
795 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
798 struct batadv_neigh_node *neigh_curr = NULL;
799 struct batadv_neigh_node *neigh_old = NULL;
800 struct batadv_orig_node *orig_dst_node = NULL;
801 struct batadv_gw_node *gw_node = NULL;
802 struct batadv_gw_node *curr_gw = NULL;
803 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
804 struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
805 bool out_of_range = false;
809 vid = batadv_get_vid(skb, 0);
811 if (is_multicast_ether_addr(ethhdr->h_dest))
814 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
815 ethhdr->h_dest, vid);
819 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
823 switch (atomic_read(&bat_priv->gw_mode)) {
824 case BATADV_GW_MODE_SERVER:
825 /* If we are a GW then we are our best GW. We can artificially
826 * set the tq towards ourself as the maximum value
828 curr_tq_avg = BATADV_TQ_MAX_VALUE;
830 case BATADV_GW_MODE_CLIENT:
831 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
835 /* packet is going to our gateway */
836 if (curr_gw->orig_node == orig_dst_node)
839 /* If the dhcp packet has been sent to a different gw,
840 * we have to evaluate whether the old gw is still
843 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
848 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
853 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
854 batadv_neigh_ifinfo_free_ref(curr_ifinfo);
857 case BATADV_GW_MODE_OFF:
862 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
866 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
870 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
872 batadv_neigh_ifinfo_free_ref(old_ifinfo);
876 batadv_orig_node_free_ref(orig_dst_node);
878 batadv_gw_node_free_ref(curr_gw);
880 batadv_gw_node_free_ref(gw_node);
882 batadv_neigh_node_free_ref(neigh_old);
884 batadv_neigh_node_free_ref(neigh_curr);