1 /* Copyright (C) 2009-2016 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/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>
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
64 * batadv_gw_node_release - release gw_node from lists and queue for free after
66 * @ref: kref pointer of the gw_node
68 static void batadv_gw_node_release(struct kref *ref)
70 struct batadv_gw_node *gw_node;
72 gw_node = container_of(ref, struct batadv_gw_node, refcount);
74 batadv_orig_node_free_ref(gw_node->orig_node);
75 kfree_rcu(gw_node, rcu);
79 * batadv_gw_node_free_ref - decrement the gw_node refcounter and possibly
81 * @gw_node: gateway node to free
83 static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
85 kref_put(&gw_node->refcount, batadv_gw_node_release);
88 static struct batadv_gw_node *
89 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
91 struct batadv_gw_node *gw_node;
94 gw_node = rcu_dereference(bat_priv->gw.curr_gw);
98 if (!kref_get_unless_zero(&gw_node->refcount))
106 struct batadv_orig_node *
107 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
109 struct batadv_gw_node *gw_node;
110 struct batadv_orig_node *orig_node = NULL;
112 gw_node = batadv_gw_get_selected_gw_node(bat_priv);
117 orig_node = gw_node->orig_node;
121 if (!kref_get_unless_zero(&orig_node->refcount))
128 batadv_gw_node_free_ref(gw_node);
132 static void batadv_gw_select(struct batadv_priv *bat_priv,
133 struct batadv_gw_node *new_gw_node)
135 struct batadv_gw_node *curr_gw_node;
137 spin_lock_bh(&bat_priv->gw.list_lock);
139 if (new_gw_node && !kref_get_unless_zero(&new_gw_node->refcount))
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);
146 batadv_gw_node_free_ref(curr_gw_node);
148 spin_unlock_bh(&bat_priv->gw.list_lock);
152 * batadv_gw_reselect - force a gateway reselection
153 * @bat_priv: the bat priv with all the soft interface information
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.
159 * This means that invoking batadv_gw_reselect() does not guarantee a gateway
160 * change and therefore a uevent is not necessarily expected.
162 void batadv_gw_reselect(struct batadv_priv *bat_priv)
164 atomic_set(&bat_priv->gw.reselect, 1);
167 static struct batadv_gw_node *
168 batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
170 struct batadv_neigh_node *router;
171 struct batadv_neigh_ifinfo *router_ifinfo;
172 struct batadv_gw_node *gw_node, *curr_gw = NULL;
173 u64 max_gw_factor = 0;
174 u64 tmp_gw_factor = 0;
177 struct batadv_orig_node *orig_node;
180 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
181 orig_node = gw_node->orig_node;
182 router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
186 router_ifinfo = batadv_neigh_ifinfo_get(router,
191 if (!kref_get_unless_zero(&gw_node->refcount))
194 tq_avg = router_ifinfo->bat_iv.tq_avg;
196 switch (atomic_read(&bat_priv->gw_sel_class)) {
197 case 1: /* fast connection */
198 tmp_gw_factor = tq_avg * tq_avg;
199 tmp_gw_factor *= gw_node->bandwidth_down;
200 tmp_gw_factor *= 100 * 100;
201 tmp_gw_factor >>= 18;
203 if ((tmp_gw_factor > max_gw_factor) ||
204 ((tmp_gw_factor == max_gw_factor) &&
205 (tq_avg > max_tq))) {
207 batadv_gw_node_free_ref(curr_gw);
209 kref_get(&curr_gw->refcount);
213 default: /* 2: stable connection (use best statistic)
214 * 3: fast-switch (use best statistic but change as
215 * soon as a better gateway appears)
216 * XX: late-switch (use best statistic but change as
217 * soon as a better gateway appears which has
218 * $routing_class more tq points)
220 if (tq_avg > max_tq) {
222 batadv_gw_node_free_ref(curr_gw);
224 kref_get(&curr_gw->refcount);
232 if (tmp_gw_factor > max_gw_factor)
233 max_gw_factor = tmp_gw_factor;
235 batadv_gw_node_free_ref(gw_node);
238 batadv_neigh_node_free_ref(router);
240 batadv_neigh_ifinfo_free_ref(router_ifinfo);
248 * batadv_gw_check_client_stop - check if client mode has been switched off
249 * @bat_priv: the bat priv with all the soft interface information
251 * This function assumes the caller has checked that the gw state *is actually
252 * changing*. This function is not supposed to be called when there is no state
255 void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
257 struct batadv_gw_node *curr_gw;
259 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
262 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
266 /* deselect the current gateway so that next time that client mode is
267 * enabled a proper GW_ADD event can be sent
269 batadv_gw_select(bat_priv, NULL);
271 /* if batman-adv is switching the gw client mode off and a gateway was
272 * already selected, send a DEL uevent
274 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
276 batadv_gw_node_free_ref(curr_gw);
279 void batadv_gw_election(struct batadv_priv *bat_priv)
281 struct batadv_gw_node *curr_gw = NULL;
282 struct batadv_gw_node *next_gw = NULL;
283 struct batadv_neigh_node *router = NULL;
284 struct batadv_neigh_ifinfo *router_ifinfo = NULL;
285 char gw_addr[18] = { '\0' };
287 if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
290 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
292 if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
295 next_gw = batadv_gw_get_best_gw_node(bat_priv);
297 if (curr_gw == next_gw)
301 sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
303 router = batadv_orig_router_get(next_gw->orig_node,
306 batadv_gw_reselect(bat_priv);
310 router_ifinfo = batadv_neigh_ifinfo_get(router,
312 if (!router_ifinfo) {
313 batadv_gw_reselect(bat_priv);
318 if ((curr_gw) && (!next_gw)) {
319 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
320 "Removing selected gateway - no gateway in range\n");
321 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
323 } else if ((!curr_gw) && (next_gw)) {
324 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
325 "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
326 next_gw->orig_node->orig,
327 next_gw->bandwidth_down / 10,
328 next_gw->bandwidth_down % 10,
329 next_gw->bandwidth_up / 10,
330 next_gw->bandwidth_up % 10,
331 router_ifinfo->bat_iv.tq_avg);
332 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
335 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
336 "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
337 next_gw->orig_node->orig,
338 next_gw->bandwidth_down / 10,
339 next_gw->bandwidth_down % 10,
340 next_gw->bandwidth_up / 10,
341 next_gw->bandwidth_up % 10,
342 router_ifinfo->bat_iv.tq_avg);
343 batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
347 batadv_gw_select(bat_priv, next_gw);
351 batadv_gw_node_free_ref(curr_gw);
353 batadv_gw_node_free_ref(next_gw);
355 batadv_neigh_node_free_ref(router);
357 batadv_neigh_ifinfo_free_ref(router_ifinfo);
360 void batadv_gw_check_election(struct batadv_priv *bat_priv,
361 struct batadv_orig_node *orig_node)
363 struct batadv_neigh_ifinfo *router_orig_tq = NULL;
364 struct batadv_neigh_ifinfo *router_gw_tq = NULL;
365 struct batadv_orig_node *curr_gw_orig;
366 struct batadv_neigh_node *router_gw = NULL;
367 struct batadv_neigh_node *router_orig = NULL;
368 u8 gw_tq_avg, orig_tq_avg;
370 curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
374 router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
378 router_gw_tq = batadv_neigh_ifinfo_get(router_gw,
383 /* this node already is the gateway */
384 if (curr_gw_orig == orig_node)
387 router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
391 router_orig_tq = batadv_neigh_ifinfo_get(router_orig,
396 gw_tq_avg = router_gw_tq->bat_iv.tq_avg;
397 orig_tq_avg = router_orig_tq->bat_iv.tq_avg;
399 /* the TQ value has to be better */
400 if (orig_tq_avg < gw_tq_avg)
403 /* if the routing class is greater than 3 the value tells us how much
404 * greater the TQ value of the new gateway must be
406 if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
407 (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
410 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
411 "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
412 gw_tq_avg, orig_tq_avg);
415 batadv_gw_reselect(bat_priv);
418 batadv_orig_node_free_ref(curr_gw_orig);
420 batadv_neigh_node_free_ref(router_gw);
422 batadv_neigh_node_free_ref(router_orig);
424 batadv_neigh_ifinfo_free_ref(router_gw_tq);
426 batadv_neigh_ifinfo_free_ref(router_orig_tq);
430 * batadv_gw_node_add - add gateway node to list of available gateways
431 * @bat_priv: the bat priv with all the soft interface information
432 * @orig_node: originator announcing gateway capabilities
433 * @gateway: announced bandwidth information
435 static void batadv_gw_node_add(struct batadv_priv *bat_priv,
436 struct batadv_orig_node *orig_node,
437 struct batadv_tvlv_gateway_data *gateway)
439 struct batadv_gw_node *gw_node;
441 if (gateway->bandwidth_down == 0)
444 if (!kref_get_unless_zero(&orig_node->refcount))
447 gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
449 batadv_orig_node_free_ref(orig_node);
453 INIT_HLIST_NODE(&gw_node->list);
454 gw_node->orig_node = orig_node;
455 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
456 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
457 kref_init(&gw_node->refcount);
459 spin_lock_bh(&bat_priv->gw.list_lock);
460 hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list);
461 spin_unlock_bh(&bat_priv->gw.list_lock);
463 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
464 "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
466 ntohl(gateway->bandwidth_down) / 10,
467 ntohl(gateway->bandwidth_down) % 10,
468 ntohl(gateway->bandwidth_up) / 10,
469 ntohl(gateway->bandwidth_up) % 10);
473 * batadv_gw_node_get - retrieve gateway node from list of available gateways
474 * @bat_priv: the bat priv with all the soft interface information
475 * @orig_node: originator announcing gateway capabilities
477 * Return: gateway node if found or NULL otherwise.
479 static struct batadv_gw_node *
480 batadv_gw_node_get(struct batadv_priv *bat_priv,
481 struct batadv_orig_node *orig_node)
483 struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
486 hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.list, list) {
487 if (gw_node_tmp->orig_node != orig_node)
490 if (!kref_get_unless_zero(&gw_node_tmp->refcount))
493 gw_node = gw_node_tmp;
502 * batadv_gw_node_update - update list of available gateways with changed
503 * bandwidth information
504 * @bat_priv: the bat priv with all the soft interface information
505 * @orig_node: originator announcing gateway capabilities
506 * @gateway: announced bandwidth information
508 void batadv_gw_node_update(struct batadv_priv *bat_priv,
509 struct batadv_orig_node *orig_node,
510 struct batadv_tvlv_gateway_data *gateway)
512 struct batadv_gw_node *gw_node, *curr_gw = NULL;
514 gw_node = batadv_gw_node_get(bat_priv, orig_node);
516 batadv_gw_node_add(bat_priv, orig_node, gateway);
520 if ((gw_node->bandwidth_down == ntohl(gateway->bandwidth_down)) &&
521 (gw_node->bandwidth_up == ntohl(gateway->bandwidth_up)))
524 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
525 "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
527 gw_node->bandwidth_down / 10,
528 gw_node->bandwidth_down % 10,
529 gw_node->bandwidth_up / 10,
530 gw_node->bandwidth_up % 10,
531 ntohl(gateway->bandwidth_down) / 10,
532 ntohl(gateway->bandwidth_down) % 10,
533 ntohl(gateway->bandwidth_up) / 10,
534 ntohl(gateway->bandwidth_up) % 10);
536 gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
537 gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
539 if (ntohl(gateway->bandwidth_down) == 0) {
540 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
541 "Gateway %pM removed from gateway list\n",
544 /* Note: We don't need a NULL check here, since curr_gw never
547 spin_lock_bh(&bat_priv->gw.list_lock);
548 if (!hlist_unhashed(&gw_node->list)) {
549 hlist_del_init_rcu(&gw_node->list);
550 batadv_gw_node_free_ref(gw_node);
552 spin_unlock_bh(&bat_priv->gw.list_lock);
554 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
555 if (gw_node == curr_gw)
556 batadv_gw_reselect(bat_priv);
559 batadv_gw_node_free_ref(curr_gw);
564 batadv_gw_node_free_ref(gw_node);
567 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
568 struct batadv_orig_node *orig_node)
570 struct batadv_tvlv_gateway_data gateway;
572 gateway.bandwidth_down = 0;
573 gateway.bandwidth_up = 0;
575 batadv_gw_node_update(bat_priv, orig_node, &gateway);
578 void batadv_gw_node_free(struct batadv_priv *bat_priv)
580 struct batadv_gw_node *gw_node;
581 struct hlist_node *node_tmp;
583 spin_lock_bh(&bat_priv->gw.list_lock);
584 hlist_for_each_entry_safe(gw_node, node_tmp,
585 &bat_priv->gw.list, list) {
586 hlist_del_init_rcu(&gw_node->list);
587 batadv_gw_node_free_ref(gw_node);
589 spin_unlock_bh(&bat_priv->gw.list_lock);
592 /* fails if orig_node has no router */
593 static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
594 struct seq_file *seq,
595 const struct batadv_gw_node *gw_node)
597 struct batadv_gw_node *curr_gw;
598 struct batadv_neigh_node *router;
599 struct batadv_neigh_ifinfo *router_ifinfo = NULL;
602 router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
606 router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
610 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
612 seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
613 (curr_gw == gw_node ? "=>" : " "),
614 gw_node->orig_node->orig,
615 router_ifinfo->bat_iv.tq_avg, router->addr,
616 router->if_incoming->net_dev->name,
617 gw_node->bandwidth_down / 10,
618 gw_node->bandwidth_down % 10,
619 gw_node->bandwidth_up / 10,
620 gw_node->bandwidth_up % 10);
621 ret = seq_has_overflowed(seq) ? -1 : 0;
624 batadv_gw_node_free_ref(curr_gw);
627 batadv_neigh_ifinfo_free_ref(router_ifinfo);
629 batadv_neigh_node_free_ref(router);
633 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
635 struct net_device *net_dev = (struct net_device *)seq->private;
636 struct batadv_priv *bat_priv = netdev_priv(net_dev);
637 struct batadv_hard_iface *primary_if;
638 struct batadv_gw_node *gw_node;
641 primary_if = batadv_seq_print_text_primary_if_get(seq);
646 " %-12s (%s/%i) %17s [%10s]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
647 "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
648 BATADV_SOURCE_VERSION, primary_if->net_dev->name,
649 primary_if->net_dev->dev_addr, net_dev->name);
652 hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
653 /* fails if orig_node has no router */
654 if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
662 seq_puts(seq, "No gateways in range ...\n");
666 batadv_hardif_free_ref(primary_if);
671 * batadv_gw_dhcp_recipient_get - check if a packet is a DHCP message
672 * @skb: the packet to check
673 * @header_len: a pointer to the batman-adv header size
674 * @chaddr: buffer where the client address will be stored. Valid
675 * only if the function returns BATADV_DHCP_TO_CLIENT
677 * This function may re-allocate the data buffer of the skb passed as argument.
680 * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
682 * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
683 * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
685 enum batadv_dhcp_recipient
686 batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
689 enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
690 struct ethhdr *ethhdr;
692 struct ipv6hdr *ipv6hdr;
693 struct udphdr *udphdr;
694 struct vlan_ethhdr *vhdr;
699 /* check for ethernet header */
700 if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
701 return BATADV_DHCP_NO;
703 ethhdr = eth_hdr(skb);
704 proto = ethhdr->h_proto;
705 *header_len += ETH_HLEN;
707 /* check for initial vlan header */
708 if (proto == htons(ETH_P_8021Q)) {
709 if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
710 return BATADV_DHCP_NO;
712 vhdr = vlan_eth_hdr(skb);
713 proto = vhdr->h_vlan_encapsulated_proto;
714 *header_len += VLAN_HLEN;
717 /* check for ip header */
719 case htons(ETH_P_IP):
720 if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
721 return BATADV_DHCP_NO;
723 iphdr = (struct iphdr *)(skb->data + *header_len);
724 *header_len += iphdr->ihl * 4;
726 /* check for udp header */
727 if (iphdr->protocol != IPPROTO_UDP)
728 return BATADV_DHCP_NO;
731 case htons(ETH_P_IPV6):
732 if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
733 return BATADV_DHCP_NO;
735 ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
736 *header_len += sizeof(*ipv6hdr);
738 /* check for udp header */
739 if (ipv6hdr->nexthdr != IPPROTO_UDP)
740 return BATADV_DHCP_NO;
744 return BATADV_DHCP_NO;
747 if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
748 return BATADV_DHCP_NO;
750 udphdr = (struct udphdr *)(skb->data + *header_len);
751 *header_len += sizeof(*udphdr);
753 /* check for bootp port */
755 case htons(ETH_P_IP):
756 if (udphdr->dest == htons(67))
757 ret = BATADV_DHCP_TO_SERVER;
758 else if (udphdr->source == htons(67))
759 ret = BATADV_DHCP_TO_CLIENT;
761 case htons(ETH_P_IPV6):
762 if (udphdr->dest == htons(547))
763 ret = BATADV_DHCP_TO_SERVER;
764 else if (udphdr->source == htons(547))
765 ret = BATADV_DHCP_TO_CLIENT;
769 chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
770 /* store the client address if the message is going to a client */
771 if (ret == BATADV_DHCP_TO_CLIENT &&
772 pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) {
773 /* check if the DHCP packet carries an Ethernet DHCP */
774 p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
775 if (*p != BATADV_DHCP_HTYPE_ETHERNET)
776 return BATADV_DHCP_NO;
778 /* check if the DHCP packet carries a valid Ethernet address */
779 p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
781 return BATADV_DHCP_NO;
783 ether_addr_copy(chaddr, skb->data + chaddr_offset);
790 * batadv_gw_out_of_range - check if the dhcp request destination is the best gw
791 * @bat_priv: the bat priv with all the soft interface information
792 * @skb: the outgoing packet
794 * Check if the skb is a DHCP request and if it is sent to the current best GW
795 * server. Due to topology changes it may be the case that the GW server
796 * previously selected is not the best one anymore.
798 * This call might reallocate skb data.
799 * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
801 * Return: true if the packet destination is unicast and it is not the best gw,
804 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
807 struct batadv_neigh_node *neigh_curr = NULL;
808 struct batadv_neigh_node *neigh_old = NULL;
809 struct batadv_orig_node *orig_dst_node = NULL;
810 struct batadv_gw_node *gw_node = NULL;
811 struct batadv_gw_node *curr_gw = NULL;
812 struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
813 struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
814 bool out_of_range = false;
818 vid = batadv_get_vid(skb, 0);
820 orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
821 ethhdr->h_dest, vid);
825 gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
829 switch (atomic_read(&bat_priv->gw_mode)) {
830 case BATADV_GW_MODE_SERVER:
831 /* If we are a GW then we are our best GW. We can artificially
832 * set the tq towards ourself as the maximum value
834 curr_tq_avg = BATADV_TQ_MAX_VALUE;
836 case BATADV_GW_MODE_CLIENT:
837 curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
841 /* packet is going to our gateway */
842 if (curr_gw->orig_node == orig_dst_node)
845 /* If the dhcp packet has been sent to a different gw,
846 * we have to evaluate whether the old gw is still
849 neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
854 curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
859 curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
860 batadv_neigh_ifinfo_free_ref(curr_ifinfo);
863 case BATADV_GW_MODE_OFF:
868 neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
872 old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
876 if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
878 batadv_neigh_ifinfo_free_ref(old_ifinfo);
882 batadv_orig_node_free_ref(orig_dst_node);
884 batadv_gw_node_free_ref(curr_gw);
886 batadv_gw_node_free_ref(gw_node);
888 batadv_neigh_node_free_ref(neigh_old);
890 batadv_neigh_node_free_ref(neigh_curr);