GNU Linux-libre 4.14.266-gnu1
[releases.git] / net / batman-adv / routing.c
1 /* Copyright (C) 2007-2017  B.A.T.M.A.N. contributors:
2  *
3  * Marek Lindner, Simon Wunderlich
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 "routing.h"
19 #include "main.h"
20
21 #include <linux/atomic.h>
22 #include <linux/byteorder/generic.h>
23 #include <linux/compiler.h>
24 #include <linux/errno.h>
25 #include <linux/etherdevice.h>
26 #include <linux/if_ether.h>
27 #include <linux/jiffies.h>
28 #include <linux/kref.h>
29 #include <linux/netdevice.h>
30 #include <linux/printk.h>
31 #include <linux/rculist.h>
32 #include <linux/rcupdate.h>
33 #include <linux/skbuff.h>
34 #include <linux/spinlock.h>
35 #include <linux/stddef.h>
36
37 #include "bitarray.h"
38 #include "bridge_loop_avoidance.h"
39 #include "distributed-arp-table.h"
40 #include "fragmentation.h"
41 #include "hard-interface.h"
42 #include "icmp_socket.h"
43 #include "log.h"
44 #include "network-coding.h"
45 #include "originator.h"
46 #include "packet.h"
47 #include "send.h"
48 #include "soft-interface.h"
49 #include "tp_meter.h"
50 #include "translation-table.h"
51 #include "tvlv.h"
52
53 static int batadv_route_unicast_packet(struct sk_buff *skb,
54                                        struct batadv_hard_iface *recv_if);
55
56 /**
57  * _batadv_update_route - set the router for this originator
58  * @bat_priv: the bat priv with all the soft interface information
59  * @orig_node: orig node which is to be configured
60  * @recv_if: the receive interface for which this route is set
61  * @neigh_node: neighbor which should be the next router
62  *
63  * This function does not perform any error checks
64  */
65 static void _batadv_update_route(struct batadv_priv *bat_priv,
66                                  struct batadv_orig_node *orig_node,
67                                  struct batadv_hard_iface *recv_if,
68                                  struct batadv_neigh_node *neigh_node)
69 {
70         struct batadv_orig_ifinfo *orig_ifinfo;
71         struct batadv_neigh_node *curr_router;
72
73         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
74         if (!orig_ifinfo)
75                 return;
76
77         spin_lock_bh(&orig_node->neigh_list_lock);
78         /* curr_router used earlier may not be the current orig_ifinfo->router
79          * anymore because it was dereferenced outside of the neigh_list_lock
80          * protected region. After the new best neighbor has replace the current
81          * best neighbor the reference counter needs to decrease. Consequently,
82          * the code needs to ensure the curr_router variable contains a pointer
83          * to the replaced best neighbor.
84          */
85         curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
86
87         /* increase refcount of new best neighbor */
88         if (neigh_node)
89                 kref_get(&neigh_node->refcount);
90
91         rcu_assign_pointer(orig_ifinfo->router, neigh_node);
92         spin_unlock_bh(&orig_node->neigh_list_lock);
93         batadv_orig_ifinfo_put(orig_ifinfo);
94
95         /* route deleted */
96         if ((curr_router) && (!neigh_node)) {
97                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
98                            "Deleting route towards: %pM\n", orig_node->orig);
99                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
100                                           "Deleted route towards originator");
101
102         /* route added */
103         } else if ((!curr_router) && (neigh_node)) {
104                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
105                            "Adding route towards: %pM (via %pM)\n",
106                            orig_node->orig, neigh_node->addr);
107         /* route changed */
108         } else if (neigh_node && curr_router) {
109                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
110                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
111                            orig_node->orig, neigh_node->addr,
112                            curr_router->addr);
113         }
114
115         /* decrease refcount of previous best neighbor */
116         if (curr_router)
117                 batadv_neigh_node_put(curr_router);
118 }
119
120 /**
121  * batadv_update_route - set the router for this originator
122  * @bat_priv: the bat priv with all the soft interface information
123  * @orig_node: orig node which is to be configured
124  * @recv_if: the receive interface for which this route is set
125  * @neigh_node: neighbor which should be the next router
126  */
127 void batadv_update_route(struct batadv_priv *bat_priv,
128                          struct batadv_orig_node *orig_node,
129                          struct batadv_hard_iface *recv_if,
130                          struct batadv_neigh_node *neigh_node)
131 {
132         struct batadv_neigh_node *router = NULL;
133
134         if (!orig_node)
135                 goto out;
136
137         router = batadv_orig_router_get(orig_node, recv_if);
138
139         if (router != neigh_node)
140                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
141
142 out:
143         if (router)
144                 batadv_neigh_node_put(router);
145 }
146
147 /**
148  * batadv_window_protected - checks whether the host restarted and is in the
149  *  protection time.
150  * @bat_priv: the bat priv with all the soft interface information
151  * @seq_num_diff: difference between the current/received sequence number and
152  *  the last sequence number
153  * @seq_old_max_diff: maximum age of sequence number not considered as restart
154  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
155  *  is detected
156  * @protection_started: is set to true if the protection window was started,
157  *   doesn't change otherwise.
158  *
159  * Return:
160  *  false if the packet is to be accepted.
161  *  true if the packet is to be ignored.
162  */
163 bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
164                              s32 seq_old_max_diff, unsigned long *last_reset,
165                              bool *protection_started)
166 {
167         if (seq_num_diff <= -seq_old_max_diff ||
168             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
169                 if (!batadv_has_timed_out(*last_reset,
170                                           BATADV_RESET_PROTECTION_MS))
171                         return true;
172
173                 *last_reset = jiffies;
174                 if (protection_started)
175                         *protection_started = true;
176                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
177                            "old packet received, start protection\n");
178         }
179
180         return false;
181 }
182
183 bool batadv_check_management_packet(struct sk_buff *skb,
184                                     struct batadv_hard_iface *hard_iface,
185                                     int header_len)
186 {
187         struct ethhdr *ethhdr;
188
189         /* drop packet if it has not necessary minimum size */
190         if (unlikely(!pskb_may_pull(skb, header_len)))
191                 return false;
192
193         ethhdr = eth_hdr(skb);
194
195         /* packet with broadcast indication but unicast recipient */
196         if (!is_broadcast_ether_addr(ethhdr->h_dest))
197                 return false;
198
199         /* packet with invalid sender address */
200         if (!is_valid_ether_addr(ethhdr->h_source))
201                 return false;
202
203         /* create a copy of the skb, if needed, to modify it. */
204         if (skb_cow(skb, 0) < 0)
205                 return false;
206
207         /* keep skb linear */
208         if (skb_linearize(skb) < 0)
209                 return false;
210
211         return true;
212 }
213
214 /**
215  * batadv_recv_my_icmp_packet - receive an icmp packet locally
216  * @bat_priv: the bat priv with all the soft interface information
217  * @skb: icmp packet to process
218  *
219  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
220  * otherwise.
221  */
222 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
223                                       struct sk_buff *skb)
224 {
225         struct batadv_hard_iface *primary_if = NULL;
226         struct batadv_orig_node *orig_node = NULL;
227         struct batadv_icmp_header *icmph;
228         int res, ret = NET_RX_DROP;
229
230         icmph = (struct batadv_icmp_header *)skb->data;
231
232         switch (icmph->msg_type) {
233         case BATADV_ECHO_REPLY:
234         case BATADV_DESTINATION_UNREACHABLE:
235         case BATADV_TTL_EXCEEDED:
236                 /* receive the packet */
237                 if (skb_linearize(skb) < 0)
238                         break;
239
240                 batadv_socket_receive_packet(icmph, skb->len);
241                 break;
242         case BATADV_ECHO_REQUEST:
243                 /* answer echo request (ping) */
244                 primary_if = batadv_primary_if_get_selected(bat_priv);
245                 if (!primary_if)
246                         goto out;
247
248                 /* get routing information */
249                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
250                 if (!orig_node)
251                         goto out;
252
253                 /* create a copy of the skb, if needed, to modify it. */
254                 if (skb_cow(skb, ETH_HLEN) < 0)
255                         goto out;
256
257                 icmph = (struct batadv_icmp_header *)skb->data;
258
259                 ether_addr_copy(icmph->dst, icmph->orig);
260                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
261                 icmph->msg_type = BATADV_ECHO_REPLY;
262                 icmph->ttl = BATADV_TTL;
263
264                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
265                 if (res == NET_XMIT_SUCCESS)
266                         ret = NET_RX_SUCCESS;
267
268                 /* skb was consumed */
269                 skb = NULL;
270                 break;
271         case BATADV_TP:
272                 if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet)))
273                         goto out;
274
275                 batadv_tp_meter_recv(bat_priv, skb);
276                 ret = NET_RX_SUCCESS;
277                 /* skb was consumed */
278                 skb = NULL;
279                 goto out;
280         default:
281                 /* drop unknown type */
282                 goto out;
283         }
284 out:
285         if (primary_if)
286                 batadv_hardif_put(primary_if);
287         if (orig_node)
288                 batadv_orig_node_put(orig_node);
289
290         kfree_skb(skb);
291
292         return ret;
293 }
294
295 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
296                                          struct sk_buff *skb)
297 {
298         struct batadv_hard_iface *primary_if = NULL;
299         struct batadv_orig_node *orig_node = NULL;
300         struct batadv_icmp_packet *icmp_packet;
301         int res, ret = NET_RX_DROP;
302
303         icmp_packet = (struct batadv_icmp_packet *)skb->data;
304
305         /* send TTL exceeded if packet is an echo request (traceroute) */
306         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
307                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
308                          icmp_packet->orig, icmp_packet->dst);
309                 goto out;
310         }
311
312         primary_if = batadv_primary_if_get_selected(bat_priv);
313         if (!primary_if)
314                 goto out;
315
316         /* get routing information */
317         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
318         if (!orig_node)
319                 goto out;
320
321         /* create a copy of the skb, if needed, to modify it. */
322         if (skb_cow(skb, ETH_HLEN) < 0)
323                 goto out;
324
325         icmp_packet = (struct batadv_icmp_packet *)skb->data;
326
327         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
328         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
329         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
330         icmp_packet->ttl = BATADV_TTL;
331
332         res = batadv_send_skb_to_orig(skb, orig_node, NULL);
333         if (res == NET_RX_SUCCESS)
334                 ret = NET_XMIT_SUCCESS;
335
336         /* skb was consumed */
337         skb = NULL;
338
339 out:
340         if (primary_if)
341                 batadv_hardif_put(primary_if);
342         if (orig_node)
343                 batadv_orig_node_put(orig_node);
344
345         kfree_skb(skb);
346
347         return ret;
348 }
349
350 int batadv_recv_icmp_packet(struct sk_buff *skb,
351                             struct batadv_hard_iface *recv_if)
352 {
353         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
354         struct batadv_icmp_header *icmph;
355         struct batadv_icmp_packet_rr *icmp_packet_rr;
356         struct ethhdr *ethhdr;
357         struct batadv_orig_node *orig_node = NULL;
358         int hdr_size = sizeof(struct batadv_icmp_header);
359         int res, ret = NET_RX_DROP;
360
361         /* drop packet if it has not necessary minimum size */
362         if (unlikely(!pskb_may_pull(skb, hdr_size)))
363                 goto free_skb;
364
365         ethhdr = eth_hdr(skb);
366
367         /* packet with unicast indication but non-unicast recipient */
368         if (!is_valid_ether_addr(ethhdr->h_dest))
369                 goto free_skb;
370
371         /* packet with broadcast/multicast sender address */
372         if (is_multicast_ether_addr(ethhdr->h_source))
373                 goto free_skb;
374
375         /* not for me */
376         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
377                 goto free_skb;
378
379         icmph = (struct batadv_icmp_header *)skb->data;
380
381         /* add record route information if not full */
382         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
383              icmph->msg_type == BATADV_ECHO_REQUEST) &&
384             (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
385                 if (skb_linearize(skb) < 0)
386                         goto free_skb;
387
388                 /* create a copy of the skb, if needed, to modify it. */
389                 if (skb_cow(skb, ETH_HLEN) < 0)
390                         goto free_skb;
391
392                 ethhdr = eth_hdr(skb);
393                 icmph = (struct batadv_icmp_header *)skb->data;
394                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
395                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
396                         goto free_skb;
397
398                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
399                                 ethhdr->h_dest);
400                 icmp_packet_rr->rr_cur++;
401         }
402
403         /* packet for me */
404         if (batadv_is_my_mac(bat_priv, icmph->dst))
405                 return batadv_recv_my_icmp_packet(bat_priv, skb);
406
407         /* TTL exceeded */
408         if (icmph->ttl < 2)
409                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
410
411         /* get routing information */
412         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
413         if (!orig_node)
414                 goto free_skb;
415
416         /* create a copy of the skb, if needed, to modify it. */
417         if (skb_cow(skb, ETH_HLEN) < 0)
418                 goto put_orig_node;
419
420         icmph = (struct batadv_icmp_header *)skb->data;
421
422         /* decrement ttl */
423         icmph->ttl--;
424
425         /* route it */
426         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
427         if (res == NET_XMIT_SUCCESS)
428                 ret = NET_RX_SUCCESS;
429
430         /* skb was consumed */
431         skb = NULL;
432
433 put_orig_node:
434         if (orig_node)
435                 batadv_orig_node_put(orig_node);
436 free_skb:
437         kfree_skb(skb);
438
439         return ret;
440 }
441
442 /**
443  * batadv_check_unicast_packet - Check for malformed unicast packets
444  * @bat_priv: the bat priv with all the soft interface information
445  * @skb: packet to check
446  * @hdr_size: size of header to pull
447  *
448  * Check for short header and bad addresses in given packet.
449  *
450  * Return: negative value when check fails and 0 otherwise. The negative value
451  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
452  * destination or source, and -EREMOTE for non-local (other host) destination.
453  */
454 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
455                                        struct sk_buff *skb, int hdr_size)
456 {
457         struct ethhdr *ethhdr;
458
459         /* drop packet if it has not necessary minimum size */
460         if (unlikely(!pskb_may_pull(skb, hdr_size)))
461                 return -ENODATA;
462
463         ethhdr = eth_hdr(skb);
464
465         /* packet with unicast indication but non-unicast recipient */
466         if (!is_valid_ether_addr(ethhdr->h_dest))
467                 return -EBADR;
468
469         /* packet with broadcast/multicast sender address */
470         if (is_multicast_ether_addr(ethhdr->h_source))
471                 return -EBADR;
472
473         /* not for me */
474         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
475                 return -EREMOTE;
476
477         return 0;
478 }
479
480 /**
481  * batadv_last_bonding_get - Get last_bonding_candidate of orig_node
482  * @orig_node: originator node whose last bonding candidate should be retrieved
483  *
484  * Return: last bonding candidate of router or NULL if not found
485  *
486  * The object is returned with refcounter increased by 1.
487  */
488 static struct batadv_orig_ifinfo *
489 batadv_last_bonding_get(struct batadv_orig_node *orig_node)
490 {
491         struct batadv_orig_ifinfo *last_bonding_candidate;
492
493         spin_lock_bh(&orig_node->neigh_list_lock);
494         last_bonding_candidate = orig_node->last_bonding_candidate;
495
496         if (last_bonding_candidate)
497                 kref_get(&last_bonding_candidate->refcount);
498         spin_unlock_bh(&orig_node->neigh_list_lock);
499
500         return last_bonding_candidate;
501 }
502
503 /**
504  * batadv_last_bonding_replace - Replace last_bonding_candidate of orig_node
505  * @orig_node: originator node whose bonding candidates should be replaced
506  * @new_candidate: new bonding candidate or NULL
507  */
508 static void
509 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
510                             struct batadv_orig_ifinfo *new_candidate)
511 {
512         struct batadv_orig_ifinfo *old_candidate;
513
514         spin_lock_bh(&orig_node->neigh_list_lock);
515         old_candidate = orig_node->last_bonding_candidate;
516
517         if (new_candidate)
518                 kref_get(&new_candidate->refcount);
519         orig_node->last_bonding_candidate = new_candidate;
520         spin_unlock_bh(&orig_node->neigh_list_lock);
521
522         if (old_candidate)
523                 batadv_orig_ifinfo_put(old_candidate);
524 }
525
526 /**
527  * batadv_find_router - find a suitable router for this originator
528  * @bat_priv: the bat priv with all the soft interface information
529  * @orig_node: the destination node
530  * @recv_if: pointer to interface this packet was received on
531  *
532  * Return: the router which should be used for this orig_node on
533  * this interface, or NULL if not available.
534  */
535 struct batadv_neigh_node *
536 batadv_find_router(struct batadv_priv *bat_priv,
537                    struct batadv_orig_node *orig_node,
538                    struct batadv_hard_iface *recv_if)
539 {
540         struct batadv_algo_ops *bao = bat_priv->algo_ops;
541         struct batadv_neigh_node *first_candidate_router = NULL;
542         struct batadv_neigh_node *next_candidate_router = NULL;
543         struct batadv_neigh_node *router, *cand_router = NULL;
544         struct batadv_neigh_node *last_cand_router = NULL;
545         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
546         struct batadv_orig_ifinfo *next_candidate = NULL;
547         struct batadv_orig_ifinfo *last_candidate;
548         bool last_candidate_found = false;
549
550         if (!orig_node)
551                 return NULL;
552
553         router = batadv_orig_router_get(orig_node, recv_if);
554
555         if (!router)
556                 return router;
557
558         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
559          * and if activated.
560          */
561         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
562                 return router;
563
564         /* bonding: loop through the list of possible routers found
565          * for the various outgoing interfaces and find a candidate after
566          * the last chosen bonding candidate (next_candidate). If no such
567          * router is found, use the first candidate found (the previously
568          * chosen bonding candidate might have been the last one in the list).
569          * If this can't be found either, return the previously chosen
570          * router - obviously there are no other candidates.
571          */
572         rcu_read_lock();
573         last_candidate = batadv_last_bonding_get(orig_node);
574         if (last_candidate)
575                 last_cand_router = rcu_dereference(last_candidate->router);
576
577         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
578                 /* acquire some structures and references ... */
579                 if (!kref_get_unless_zero(&cand->refcount))
580                         continue;
581
582                 cand_router = rcu_dereference(cand->router);
583                 if (!cand_router)
584                         goto next;
585
586                 if (!kref_get_unless_zero(&cand_router->refcount)) {
587                         cand_router = NULL;
588                         goto next;
589                 }
590
591                 /* alternative candidate should be good enough to be
592                  * considered
593                  */
594                 if (!bao->neigh.is_similar_or_better(cand_router,
595                                                      cand->if_outgoing, router,
596                                                      recv_if))
597                         goto next;
598
599                 /* don't use the same router twice */
600                 if (last_cand_router == cand_router)
601                         goto next;
602
603                 /* mark the first possible candidate */
604                 if (!first_candidate) {
605                         kref_get(&cand_router->refcount);
606                         kref_get(&cand->refcount);
607                         first_candidate = cand;
608                         first_candidate_router = cand_router;
609                 }
610
611                 /* check if the loop has already passed the previously selected
612                  * candidate ... this function should select the next candidate
613                  * AFTER the previously used bonding candidate.
614                  */
615                 if (!last_candidate || last_candidate_found) {
616                         next_candidate = cand;
617                         next_candidate_router = cand_router;
618                         break;
619                 }
620
621                 if (last_candidate == cand)
622                         last_candidate_found = true;
623 next:
624                 /* free references */
625                 if (cand_router) {
626                         batadv_neigh_node_put(cand_router);
627                         cand_router = NULL;
628                 }
629                 batadv_orig_ifinfo_put(cand);
630         }
631         rcu_read_unlock();
632
633         /* After finding candidates, handle the three cases:
634          * 1) there is a next candidate, use that
635          * 2) there is no next candidate, use the first of the list
636          * 3) there is no candidate at all, return the default router
637          */
638         if (next_candidate) {
639                 batadv_neigh_node_put(router);
640
641                 kref_get(&next_candidate_router->refcount);
642                 router = next_candidate_router;
643                 batadv_last_bonding_replace(orig_node, next_candidate);
644         } else if (first_candidate) {
645                 batadv_neigh_node_put(router);
646
647                 kref_get(&first_candidate_router->refcount);
648                 router = first_candidate_router;
649                 batadv_last_bonding_replace(orig_node, first_candidate);
650         } else {
651                 batadv_last_bonding_replace(orig_node, NULL);
652         }
653
654         /* cleanup of candidates */
655         if (first_candidate) {
656                 batadv_neigh_node_put(first_candidate_router);
657                 batadv_orig_ifinfo_put(first_candidate);
658         }
659
660         if (next_candidate) {
661                 batadv_neigh_node_put(next_candidate_router);
662                 batadv_orig_ifinfo_put(next_candidate);
663         }
664
665         if (last_candidate)
666                 batadv_orig_ifinfo_put(last_candidate);
667
668         return router;
669 }
670
671 static int batadv_route_unicast_packet(struct sk_buff *skb,
672                                        struct batadv_hard_iface *recv_if)
673 {
674         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
675         struct batadv_orig_node *orig_node = NULL;
676         struct batadv_unicast_packet *unicast_packet;
677         struct ethhdr *ethhdr = eth_hdr(skb);
678         int res, hdr_len, ret = NET_RX_DROP;
679         unsigned int len;
680
681         unicast_packet = (struct batadv_unicast_packet *)skb->data;
682
683         /* TTL exceeded */
684         if (unicast_packet->ttl < 2) {
685                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
686                          ethhdr->h_source, unicast_packet->dest);
687                 goto free_skb;
688         }
689
690         /* get routing information */
691         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
692
693         if (!orig_node)
694                 goto free_skb;
695
696         /* create a copy of the skb, if needed, to modify it. */
697         if (skb_cow(skb, ETH_HLEN) < 0)
698                 goto put_orig_node;
699
700         /* decrement ttl */
701         unicast_packet = (struct batadv_unicast_packet *)skb->data;
702         unicast_packet->ttl--;
703
704         switch (unicast_packet->packet_type) {
705         case BATADV_UNICAST_4ADDR:
706                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
707                 break;
708         case BATADV_UNICAST:
709                 hdr_len = sizeof(struct batadv_unicast_packet);
710                 break;
711         default:
712                 /* other packet types not supported - yet */
713                 hdr_len = -1;
714                 break;
715         }
716
717         if (hdr_len > 0)
718                 batadv_skb_set_priority(skb, hdr_len);
719
720         len = skb->len;
721         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
722
723         /* translate transmit result into receive result */
724         if (res == NET_XMIT_SUCCESS) {
725                 ret = NET_RX_SUCCESS;
726                 /* skb was transmitted and consumed */
727                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
728                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
729                                    len + ETH_HLEN);
730         }
731
732         /* skb was consumed */
733         skb = NULL;
734
735 put_orig_node:
736         batadv_orig_node_put(orig_node);
737 free_skb:
738         kfree_skb(skb);
739
740         return ret;
741 }
742
743 /**
744  * batadv_reroute_unicast_packet - update the unicast header for re-routing
745  * @bat_priv: the bat priv with all the soft interface information
746  * @skb: unicast packet to process
747  * @unicast_packet: the unicast header to be updated
748  * @dst_addr: the payload destination
749  * @vid: VLAN identifier
750  *
751  * Search the translation table for dst_addr and update the unicast header with
752  * the new corresponding information (originator address where the destination
753  * client currently is and its known TTVN)
754  *
755  * Return: true if the packet header has been updated, false otherwise
756  */
757 static bool
758 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
759                               struct batadv_unicast_packet *unicast_packet,
760                               u8 *dst_addr, unsigned short vid)
761 {
762         struct batadv_orig_node *orig_node = NULL;
763         struct batadv_hard_iface *primary_if = NULL;
764         bool ret = false;
765         u8 *orig_addr, orig_ttvn;
766
767         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
768                 primary_if = batadv_primary_if_get_selected(bat_priv);
769                 if (!primary_if)
770                         goto out;
771                 orig_addr = primary_if->net_dev->dev_addr;
772                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
773         } else {
774                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
775                                                      vid);
776                 if (!orig_node)
777                         goto out;
778
779                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
780                         goto out;
781
782                 orig_addr = orig_node->orig;
783                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
784         }
785
786         /* update the packet header */
787         skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
788         ether_addr_copy(unicast_packet->dest, orig_addr);
789         unicast_packet->ttvn = orig_ttvn;
790         skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
791
792         ret = true;
793 out:
794         if (primary_if)
795                 batadv_hardif_put(primary_if);
796         if (orig_node)
797                 batadv_orig_node_put(orig_node);
798
799         return ret;
800 }
801
802 static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
803                                       struct sk_buff *skb, int hdr_len)
804 {
805         struct batadv_unicast_packet *unicast_packet;
806         struct batadv_hard_iface *primary_if;
807         struct batadv_orig_node *orig_node;
808         u8 curr_ttvn, old_ttvn;
809         struct ethhdr *ethhdr;
810         unsigned short vid;
811         int is_old_ttvn;
812
813         /* check if there is enough data before accessing it */
814         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
815                 return false;
816
817         /* create a copy of the skb (in case of for re-routing) to modify it. */
818         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
819                 return false;
820
821         unicast_packet = (struct batadv_unicast_packet *)skb->data;
822         vid = batadv_get_vid(skb, hdr_len);
823         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
824
825         /* do not reroute multicast frames in a unicast header */
826         if (is_multicast_ether_addr(ethhdr->h_dest))
827                 return true;
828
829         /* check if the destination client was served by this node and it is now
830          * roaming. In this case, it means that the node has got a ROAM_ADV
831          * message and that it knows the new destination in the mesh to re-route
832          * the packet to
833          */
834         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
835                 if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
836                                                   ethhdr->h_dest, vid))
837                         batadv_dbg_ratelimited(BATADV_DBG_TT,
838                                                bat_priv,
839                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
840                                                unicast_packet->dest,
841                                                ethhdr->h_dest);
842                 /* at this point the mesh destination should have been
843                  * substituted with the originator address found in the global
844                  * table. If not, let the packet go untouched anyway because
845                  * there is nothing the node can do
846                  */
847                 return true;
848         }
849
850         /* retrieve the TTVN known by this node for the packet destination. This
851          * value is used later to check if the node which sent (or re-routed
852          * last time) the packet had an updated information or not
853          */
854         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
855         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
856                 orig_node = batadv_orig_hash_find(bat_priv,
857                                                   unicast_packet->dest);
858                 /* if it is not possible to find the orig_node representing the
859                  * destination, the packet can immediately be dropped as it will
860                  * not be possible to deliver it
861                  */
862                 if (!orig_node)
863                         return false;
864
865                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
866                 batadv_orig_node_put(orig_node);
867         }
868
869         /* check if the TTVN contained in the packet is fresher than what the
870          * node knows
871          */
872         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
873         if (!is_old_ttvn)
874                 return true;
875
876         old_ttvn = unicast_packet->ttvn;
877         /* the packet was forged based on outdated network information. Its
878          * destination can possibly be updated and forwarded towards the new
879          * target host
880          */
881         if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
882                                           ethhdr->h_dest, vid)) {
883                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
884                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
885                                        unicast_packet->dest, ethhdr->h_dest,
886                                        old_ttvn, curr_ttvn);
887                 return true;
888         }
889
890         /* the packet has not been re-routed: either the destination is
891          * currently served by this node or there is no destination at all and
892          * it is possible to drop the packet
893          */
894         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
895                 return false;
896
897         /* update the header in order to let the packet be delivered to this
898          * node's soft interface
899          */
900         primary_if = batadv_primary_if_get_selected(bat_priv);
901         if (!primary_if)
902                 return false;
903
904         /* update the packet header */
905         skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
906         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
907         unicast_packet->ttvn = curr_ttvn;
908         skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
909
910         batadv_hardif_put(primary_if);
911
912         return true;
913 }
914
915 /**
916  * batadv_recv_unhandled_unicast_packet - receive and process packets which
917  *      are in the unicast number space but not yet known to the implementation
918  * @skb: unicast tvlv packet to process
919  * @recv_if: pointer to interface this packet was received on
920  *
921  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
922  * otherwise.
923  */
924 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
925                                          struct batadv_hard_iface *recv_if)
926 {
927         struct batadv_unicast_packet *unicast_packet;
928         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
929         int check, hdr_size = sizeof(*unicast_packet);
930
931         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
932         if (check < 0)
933                 goto free_skb;
934
935         /* we don't know about this type, drop it. */
936         unicast_packet = (struct batadv_unicast_packet *)skb->data;
937         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
938                 goto free_skb;
939
940         return batadv_route_unicast_packet(skb, recv_if);
941
942 free_skb:
943         kfree_skb(skb);
944         return NET_RX_DROP;
945 }
946
947 int batadv_recv_unicast_packet(struct sk_buff *skb,
948                                struct batadv_hard_iface *recv_if)
949 {
950         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
951         struct batadv_unicast_packet *unicast_packet;
952         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
953         u8 *orig_addr, *orig_addr_gw;
954         struct batadv_orig_node *orig_node = NULL, *orig_node_gw = NULL;
955         int check, hdr_size = sizeof(*unicast_packet);
956         enum batadv_subtype subtype;
957         int ret = NET_RX_DROP;
958         bool is4addr, is_gw;
959
960         unicast_packet = (struct batadv_unicast_packet *)skb->data;
961         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
962         /* the caller function should have already pulled 2 bytes */
963         if (is4addr)
964                 hdr_size = sizeof(*unicast_4addr_packet);
965
966         /* function returns -EREMOTE for promiscuous packets */
967         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
968
969         /* Even though the packet is not for us, we might save it to use for
970          * decoding a later received coded packet
971          */
972         if (check == -EREMOTE)
973                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
974
975         if (check < 0)
976                 goto free_skb;
977         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
978                 goto free_skb;
979
980         unicast_packet = (struct batadv_unicast_packet *)skb->data;
981
982         /* packet for me */
983         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
984                 /* If this is a unicast packet from another backgone gw,
985                  * drop it.
986                  */
987                 orig_addr_gw = eth_hdr(skb)->h_source;
988                 orig_node_gw = batadv_orig_hash_find(bat_priv, orig_addr_gw);
989                 if (orig_node_gw) {
990                         is_gw = batadv_bla_is_backbone_gw(skb, orig_node_gw,
991                                                           hdr_size);
992                         batadv_orig_node_put(orig_node_gw);
993                         if (is_gw) {
994                                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
995                                            "%s(): Dropped unicast pkt received from another backbone gw %pM.\n",
996                                            __func__, orig_addr_gw);
997                                 goto free_skb;
998                         }
999                 }
1000
1001                 if (is4addr) {
1002                         unicast_4addr_packet =
1003                                 (struct batadv_unicast_4addr_packet *)skb->data;
1004                         subtype = unicast_4addr_packet->subtype;
1005                         batadv_dat_inc_counter(bat_priv, subtype);
1006
1007                         /* Only payload data should be considered for speedy
1008                          * join. For example, DAT also uses unicast 4addr
1009                          * types, but those packets should not be considered
1010                          * for speedy join, since the clients do not actually
1011                          * reside at the sending originator.
1012                          */
1013                         if (subtype == BATADV_P_DATA) {
1014                                 orig_addr = unicast_4addr_packet->src;
1015                                 orig_node = batadv_orig_hash_find(bat_priv,
1016                                                                   orig_addr);
1017                         }
1018                 }
1019
1020                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
1021                                                           hdr_size))
1022                         goto rx_success;
1023                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
1024                                                         hdr_size))
1025                         goto rx_success;
1026
1027                 batadv_interface_rx(recv_if->soft_iface, skb, hdr_size,
1028                                     orig_node);
1029
1030 rx_success:
1031                 if (orig_node)
1032                         batadv_orig_node_put(orig_node);
1033
1034                 return NET_RX_SUCCESS;
1035         }
1036
1037         ret = batadv_route_unicast_packet(skb, recv_if);
1038         /* skb was consumed */
1039         skb = NULL;
1040
1041 free_skb:
1042         kfree_skb(skb);
1043
1044         return ret;
1045 }
1046
1047 /**
1048  * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
1049  * @skb: unicast tvlv packet to process
1050  * @recv_if: pointer to interface this packet was received on
1051  *
1052  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1053  * otherwise.
1054  */
1055 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
1056                              struct batadv_hard_iface *recv_if)
1057 {
1058         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1059         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
1060         unsigned char *tvlv_buff;
1061         u16 tvlv_buff_len;
1062         int hdr_size = sizeof(*unicast_tvlv_packet);
1063         int ret = NET_RX_DROP;
1064
1065         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1066                 goto free_skb;
1067
1068         /* the header is likely to be modified while forwarding */
1069         if (skb_cow(skb, hdr_size) < 0)
1070                 goto free_skb;
1071
1072         /* packet needs to be linearized to access the tvlv content */
1073         if (skb_linearize(skb) < 0)
1074                 goto free_skb;
1075
1076         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1077
1078         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1079         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1080
1081         if (tvlv_buff_len > skb->len - hdr_size)
1082                 goto free_skb;
1083
1084         ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
1085                                              unicast_tvlv_packet->src,
1086                                              unicast_tvlv_packet->dst,
1087                                              tvlv_buff, tvlv_buff_len);
1088
1089         if (ret != NET_RX_SUCCESS) {
1090                 ret = batadv_route_unicast_packet(skb, recv_if);
1091                 /* skb was consumed */
1092                 skb = NULL;
1093         }
1094
1095 free_skb:
1096         kfree_skb(skb);
1097
1098         return ret;
1099 }
1100
1101 /**
1102  * batadv_recv_frag_packet - process received fragment
1103  * @skb: the received fragment
1104  * @recv_if: interface that the skb is received on
1105  *
1106  * This function does one of the three following things: 1) Forward fragment, if
1107  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
1108  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1109  *
1110  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1111  */
1112 int batadv_recv_frag_packet(struct sk_buff *skb,
1113                             struct batadv_hard_iface *recv_if)
1114 {
1115         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1116         struct batadv_orig_node *orig_node_src = NULL;
1117         struct batadv_frag_packet *frag_packet;
1118         int ret = NET_RX_DROP;
1119
1120         if (batadv_check_unicast_packet(bat_priv, skb,
1121                                         sizeof(*frag_packet)) < 0)
1122                 goto free_skb;
1123
1124         frag_packet = (struct batadv_frag_packet *)skb->data;
1125         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1126         if (!orig_node_src)
1127                 goto free_skb;
1128
1129         skb->priority = frag_packet->priority + 256;
1130
1131         /* Route the fragment if it is not for us and too big to be merged. */
1132         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1133             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1134                 /* skb was consumed */
1135                 skb = NULL;
1136                 ret = NET_RX_SUCCESS;
1137                 goto put_orig_node;
1138         }
1139
1140         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1141         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1142
1143         /* Add fragment to buffer and merge if possible. */
1144         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1145                 goto put_orig_node;
1146
1147         /* Deliver merged packet to the appropriate handler, if it was
1148          * merged
1149          */
1150         if (skb) {
1151                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1152                                        &recv_if->batman_adv_ptype, NULL);
1153                 /* skb was consumed */
1154                 skb = NULL;
1155         }
1156
1157         ret = NET_RX_SUCCESS;
1158
1159 put_orig_node:
1160         batadv_orig_node_put(orig_node_src);
1161 free_skb:
1162         kfree_skb(skb);
1163
1164         return ret;
1165 }
1166
1167 int batadv_recv_bcast_packet(struct sk_buff *skb,
1168                              struct batadv_hard_iface *recv_if)
1169 {
1170         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1171         struct batadv_orig_node *orig_node = NULL;
1172         struct batadv_bcast_packet *bcast_packet;
1173         struct ethhdr *ethhdr;
1174         int hdr_size = sizeof(*bcast_packet);
1175         int ret = NET_RX_DROP;
1176         s32 seq_diff;
1177         u32 seqno;
1178
1179         /* drop packet if it has not necessary minimum size */
1180         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1181                 goto free_skb;
1182
1183         ethhdr = eth_hdr(skb);
1184
1185         /* packet with broadcast indication but unicast recipient */
1186         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1187                 goto free_skb;
1188
1189         /* packet with broadcast/multicast sender address */
1190         if (is_multicast_ether_addr(ethhdr->h_source))
1191                 goto free_skb;
1192
1193         /* ignore broadcasts sent by myself */
1194         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1195                 goto free_skb;
1196
1197         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1198
1199         /* ignore broadcasts originated by myself */
1200         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1201                 goto free_skb;
1202
1203         if (bcast_packet->ttl < 2)
1204                 goto free_skb;
1205
1206         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1207
1208         if (!orig_node)
1209                 goto free_skb;
1210
1211         spin_lock_bh(&orig_node->bcast_seqno_lock);
1212
1213         seqno = ntohl(bcast_packet->seqno);
1214         /* check whether the packet is a duplicate */
1215         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1216                             seqno))
1217                 goto spin_unlock;
1218
1219         seq_diff = seqno - orig_node->last_bcast_seqno;
1220
1221         /* check whether the packet is old and the host just restarted. */
1222         if (batadv_window_protected(bat_priv, seq_diff,
1223                                     BATADV_BCAST_MAX_AGE,
1224                                     &orig_node->bcast_seqno_reset, NULL))
1225                 goto spin_unlock;
1226
1227         /* mark broadcast in flood history, update window position
1228          * if required.
1229          */
1230         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1231                 orig_node->last_bcast_seqno = seqno;
1232
1233         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1234
1235         /* check whether this has been sent by another originator before */
1236         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1237                 goto free_skb;
1238
1239         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1240
1241         /* rebroadcast packet */
1242         batadv_add_bcast_packet_to_list(bat_priv, skb, 1, false);
1243
1244         /* don't hand the broadcast up if it is from an originator
1245          * from the same backbone.
1246          */
1247         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1248                 goto free_skb;
1249
1250         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1251                 goto rx_success;
1252         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1253                 goto rx_success;
1254
1255         /* broadcast for me */
1256         batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node);
1257
1258 rx_success:
1259         ret = NET_RX_SUCCESS;
1260         goto out;
1261
1262 spin_unlock:
1263         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1264 free_skb:
1265         kfree_skb(skb);
1266 out:
1267         if (orig_node)
1268                 batadv_orig_node_put(orig_node);
1269         return ret;
1270 }