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TOMOYO Linux Cross Reference
Linux/net/batman-adv/routing.c

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Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0
  2 /* Copyright (C) B.A.T.M.A.N. contributors:
  3  *
  4  * Marek Lindner, Simon Wunderlich
  5  */
  6 
  7 #include "routing.h"
  8 #include "main.h"
  9 
 10 #include <linux/atomic.h>
 11 #include <linux/byteorder/generic.h>
 12 #include <linux/compiler.h>
 13 #include <linux/errno.h>
 14 #include <linux/etherdevice.h>
 15 #include <linux/if_ether.h>
 16 #include <linux/jiffies.h>
 17 #include <linux/kref.h>
 18 #include <linux/netdevice.h>
 19 #include <linux/printk.h>
 20 #include <linux/rculist.h>
 21 #include <linux/rcupdate.h>
 22 #include <linux/skbuff.h>
 23 #include <linux/spinlock.h>
 24 #include <linux/stddef.h>
 25 #include <uapi/linux/batadv_packet.h>
 26 
 27 #include "bitarray.h"
 28 #include "bridge_loop_avoidance.h"
 29 #include "distributed-arp-table.h"
 30 #include "fragmentation.h"
 31 #include "hard-interface.h"
 32 #include "log.h"
 33 #include "network-coding.h"
 34 #include "originator.h"
 35 #include "send.h"
 36 #include "soft-interface.h"
 37 #include "tp_meter.h"
 38 #include "translation-table.h"
 39 #include "tvlv.h"
 40 
 41 static int batadv_route_unicast_packet(struct sk_buff *skb,
 42                                        struct batadv_hard_iface *recv_if);
 43 
 44 /**
 45  * _batadv_update_route() - set the router for this originator
 46  * @bat_priv: the bat priv with all the soft interface information
 47  * @orig_node: orig node which is to be configured
 48  * @recv_if: the receive interface for which this route is set
 49  * @neigh_node: neighbor which should be the next router
 50  *
 51  * This function does not perform any error checks
 52  */
 53 static void _batadv_update_route(struct batadv_priv *bat_priv,
 54                                  struct batadv_orig_node *orig_node,
 55                                  struct batadv_hard_iface *recv_if,
 56                                  struct batadv_neigh_node *neigh_node)
 57 {
 58         struct batadv_orig_ifinfo *orig_ifinfo;
 59         struct batadv_neigh_node *curr_router;
 60 
 61         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
 62         if (!orig_ifinfo)
 63                 return;
 64 
 65         spin_lock_bh(&orig_node->neigh_list_lock);
 66         /* curr_router used earlier may not be the current orig_ifinfo->router
 67          * anymore because it was dereferenced outside of the neigh_list_lock
 68          * protected region. After the new best neighbor has replace the current
 69          * best neighbor the reference counter needs to decrease. Consequently,
 70          * the code needs to ensure the curr_router variable contains a pointer
 71          * to the replaced best neighbor.
 72          */
 73 
 74         /* increase refcount of new best neighbor */
 75         if (neigh_node)
 76                 kref_get(&neigh_node->refcount);
 77 
 78         curr_router = rcu_replace_pointer(orig_ifinfo->router, neigh_node,
 79                                           true);
 80         spin_unlock_bh(&orig_node->neigh_list_lock);
 81         batadv_orig_ifinfo_put(orig_ifinfo);
 82 
 83         /* route deleted */
 84         if (curr_router && !neigh_node) {
 85                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
 86                            "Deleting route towards: %pM\n", orig_node->orig);
 87                 batadv_tt_global_del_orig(bat_priv, orig_node, -1,
 88                                           "Deleted route towards originator");
 89 
 90         /* route added */
 91         } else if (!curr_router && neigh_node) {
 92                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
 93                            "Adding route towards: %pM (via %pM)\n",
 94                            orig_node->orig, neigh_node->addr);
 95         /* route changed */
 96         } else if (neigh_node && curr_router) {
 97                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
 98                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
 99                            orig_node->orig, neigh_node->addr,
100                            curr_router->addr);
101         }
102 
103         /* decrease refcount of previous best neighbor */
104         batadv_neigh_node_put(curr_router);
105 }
106 
107 /**
108  * batadv_update_route() - set the router for this originator
109  * @bat_priv: the bat priv with all the soft interface information
110  * @orig_node: orig node which is to be configured
111  * @recv_if: the receive interface for which this route is set
112  * @neigh_node: neighbor which should be the next router
113  */
114 void batadv_update_route(struct batadv_priv *bat_priv,
115                          struct batadv_orig_node *orig_node,
116                          struct batadv_hard_iface *recv_if,
117                          struct batadv_neigh_node *neigh_node)
118 {
119         struct batadv_neigh_node *router = NULL;
120 
121         if (!orig_node)
122                 goto out;
123 
124         router = batadv_orig_router_get(orig_node, recv_if);
125 
126         if (router != neigh_node)
127                 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
128 
129 out:
130         batadv_neigh_node_put(router);
131 }
132 
133 /**
134  * batadv_window_protected() - checks whether the host restarted and is in the
135  *  protection time.
136  * @bat_priv: the bat priv with all the soft interface information
137  * @seq_num_diff: difference between the current/received sequence number and
138  *  the last sequence number
139  * @seq_old_max_diff: maximum age of sequence number not considered as restart
140  * @last_reset: jiffies timestamp of the last reset, will be updated when reset
141  *  is detected
142  * @protection_started: is set to true if the protection window was started,
143  *   doesn't change otherwise.
144  *
145  * Return:
146  *  false if the packet is to be accepted.
147  *  true if the packet is to be ignored.
148  */
149 bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
150                              s32 seq_old_max_diff, unsigned long *last_reset,
151                              bool *protection_started)
152 {
153         if (seq_num_diff <= -seq_old_max_diff ||
154             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
155                 if (!batadv_has_timed_out(*last_reset,
156                                           BATADV_RESET_PROTECTION_MS))
157                         return true;
158 
159                 *last_reset = jiffies;
160                 if (protection_started)
161                         *protection_started = true;
162                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
163                            "old packet received, start protection\n");
164         }
165 
166         return false;
167 }
168 
169 /**
170  * batadv_check_management_packet() - Check preconditions for management packets
171  * @skb: incoming packet buffer
172  * @hard_iface: incoming hard interface
173  * @header_len: minimal header length of packet type
174  *
175  * Return: true when management preconditions are met, false otherwise
176  */
177 bool batadv_check_management_packet(struct sk_buff *skb,
178                                     struct batadv_hard_iface *hard_iface,
179                                     int header_len)
180 {
181         struct ethhdr *ethhdr;
182 
183         /* drop packet if it has not necessary minimum size */
184         if (unlikely(!pskb_may_pull(skb, header_len)))
185                 return false;
186 
187         ethhdr = eth_hdr(skb);
188 
189         /* packet with broadcast indication but unicast recipient */
190         if (!is_broadcast_ether_addr(ethhdr->h_dest))
191                 return false;
192 
193         /* packet with invalid sender address */
194         if (!is_valid_ether_addr(ethhdr->h_source))
195                 return false;
196 
197         /* create a copy of the skb, if needed, to modify it. */
198         if (skb_cow(skb, 0) < 0)
199                 return false;
200 
201         /* keep skb linear */
202         if (skb_linearize(skb) < 0)
203                 return false;
204 
205         return true;
206 }
207 
208 /**
209  * batadv_recv_my_icmp_packet() - receive an icmp packet locally
210  * @bat_priv: the bat priv with all the soft interface information
211  * @skb: icmp packet to process
212  *
213  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
214  * otherwise.
215  */
216 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
217                                       struct sk_buff *skb)
218 {
219         struct batadv_hard_iface *primary_if = NULL;
220         struct batadv_orig_node *orig_node = NULL;
221         struct batadv_icmp_header *icmph;
222         int res, ret = NET_RX_DROP;
223 
224         icmph = (struct batadv_icmp_header *)skb->data;
225 
226         switch (icmph->msg_type) {
227         case BATADV_ECHO_REQUEST:
228                 /* answer echo request (ping) */
229                 primary_if = batadv_primary_if_get_selected(bat_priv);
230                 if (!primary_if)
231                         goto out;
232 
233                 /* get routing information */
234                 orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
235                 if (!orig_node)
236                         goto out;
237 
238                 /* create a copy of the skb, if needed, to modify it. */
239                 if (skb_cow(skb, ETH_HLEN) < 0)
240                         goto out;
241 
242                 icmph = (struct batadv_icmp_header *)skb->data;
243 
244                 ether_addr_copy(icmph->dst, icmph->orig);
245                 ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
246                 icmph->msg_type = BATADV_ECHO_REPLY;
247                 icmph->ttl = BATADV_TTL;
248 
249                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
250                 if (res == NET_XMIT_SUCCESS)
251                         ret = NET_RX_SUCCESS;
252 
253                 /* skb was consumed */
254                 skb = NULL;
255                 break;
256         case BATADV_TP:
257                 if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet)))
258                         goto out;
259 
260                 batadv_tp_meter_recv(bat_priv, skb);
261                 ret = NET_RX_SUCCESS;
262                 /* skb was consumed */
263                 skb = NULL;
264                 goto out;
265         default:
266                 /* drop unknown type */
267                 goto out;
268         }
269 out:
270         batadv_hardif_put(primary_if);
271         batadv_orig_node_put(orig_node);
272 
273         kfree_skb(skb);
274 
275         return ret;
276 }
277 
278 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
279                                          struct sk_buff *skb)
280 {
281         struct batadv_hard_iface *primary_if = NULL;
282         struct batadv_orig_node *orig_node = NULL;
283         struct batadv_icmp_packet *icmp_packet;
284         int res, ret = NET_RX_DROP;
285 
286         icmp_packet = (struct batadv_icmp_packet *)skb->data;
287 
288         /* send TTL exceeded if packet is an echo request (traceroute) */
289         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
290                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
291                          icmp_packet->orig, icmp_packet->dst);
292                 goto out;
293         }
294 
295         primary_if = batadv_primary_if_get_selected(bat_priv);
296         if (!primary_if)
297                 goto out;
298 
299         /* get routing information */
300         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
301         if (!orig_node)
302                 goto out;
303 
304         /* create a copy of the skb, if needed, to modify it. */
305         if (skb_cow(skb, ETH_HLEN) < 0)
306                 goto out;
307 
308         icmp_packet = (struct batadv_icmp_packet *)skb->data;
309 
310         ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
311         ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
312         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
313         icmp_packet->ttl = BATADV_TTL;
314 
315         res = batadv_send_skb_to_orig(skb, orig_node, NULL);
316         if (res == NET_RX_SUCCESS)
317                 ret = NET_XMIT_SUCCESS;
318 
319         /* skb was consumed */
320         skb = NULL;
321 
322 out:
323         batadv_hardif_put(primary_if);
324         batadv_orig_node_put(orig_node);
325 
326         kfree_skb(skb);
327 
328         return ret;
329 }
330 
331 /**
332  * batadv_recv_icmp_packet() - Process incoming icmp packet
333  * @skb: incoming packet buffer
334  * @recv_if: incoming hard interface
335  *
336  * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
337  */
338 int batadv_recv_icmp_packet(struct sk_buff *skb,
339                             struct batadv_hard_iface *recv_if)
340 {
341         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
342         struct batadv_icmp_header *icmph;
343         struct batadv_icmp_packet_rr *icmp_packet_rr;
344         struct ethhdr *ethhdr;
345         struct batadv_orig_node *orig_node = NULL;
346         int hdr_size = sizeof(struct batadv_icmp_header);
347         int res, ret = NET_RX_DROP;
348 
349         /* drop packet if it has not necessary minimum size */
350         if (unlikely(!pskb_may_pull(skb, hdr_size)))
351                 goto free_skb;
352 
353         ethhdr = eth_hdr(skb);
354 
355         /* packet with unicast indication but non-unicast recipient */
356         if (!is_valid_ether_addr(ethhdr->h_dest))
357                 goto free_skb;
358 
359         /* packet with broadcast/multicast sender address */
360         if (is_multicast_ether_addr(ethhdr->h_source))
361                 goto free_skb;
362 
363         /* not for me */
364         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
365                 goto free_skb;
366 
367         icmph = (struct batadv_icmp_header *)skb->data;
368 
369         /* add record route information if not full */
370         if ((icmph->msg_type == BATADV_ECHO_REPLY ||
371              icmph->msg_type == BATADV_ECHO_REQUEST) &&
372             skb->len >= sizeof(struct batadv_icmp_packet_rr)) {
373                 if (skb_linearize(skb) < 0)
374                         goto free_skb;
375 
376                 /* create a copy of the skb, if needed, to modify it. */
377                 if (skb_cow(skb, ETH_HLEN) < 0)
378                         goto free_skb;
379 
380                 ethhdr = eth_hdr(skb);
381                 icmph = (struct batadv_icmp_header *)skb->data;
382                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
383                 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
384                         goto free_skb;
385 
386                 ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
387                                 ethhdr->h_dest);
388                 icmp_packet_rr->rr_cur++;
389         }
390 
391         /* packet for me */
392         if (batadv_is_my_mac(bat_priv, icmph->dst))
393                 return batadv_recv_my_icmp_packet(bat_priv, skb);
394 
395         /* TTL exceeded */
396         if (icmph->ttl < 2)
397                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
398 
399         /* get routing information */
400         orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
401         if (!orig_node)
402                 goto free_skb;
403 
404         /* create a copy of the skb, if needed, to modify it. */
405         if (skb_cow(skb, ETH_HLEN) < 0)
406                 goto put_orig_node;
407 
408         icmph = (struct batadv_icmp_header *)skb->data;
409 
410         /* decrement ttl */
411         icmph->ttl--;
412 
413         /* route it */
414         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
415         if (res == NET_XMIT_SUCCESS)
416                 ret = NET_RX_SUCCESS;
417 
418         /* skb was consumed */
419         skb = NULL;
420 
421 put_orig_node:
422         batadv_orig_node_put(orig_node);
423 free_skb:
424         kfree_skb(skb);
425 
426         return ret;
427 }
428 
429 /**
430  * batadv_check_unicast_packet() - Check for malformed unicast packets
431  * @bat_priv: the bat priv with all the soft interface information
432  * @skb: packet to check
433  * @hdr_size: size of header to pull
434  *
435  * Checks for short header and bad addresses in the given packet.
436  *
437  * Return: negative value when check fails and 0 otherwise. The negative value
438  * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
439  * destination or source, and -EREMOTE for non-local (other host) destination.
440  */
441 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
442                                        struct sk_buff *skb, int hdr_size)
443 {
444         struct ethhdr *ethhdr;
445 
446         /* drop packet if it has not necessary minimum size */
447         if (unlikely(!pskb_may_pull(skb, hdr_size)))
448                 return -ENODATA;
449 
450         ethhdr = eth_hdr(skb);
451 
452         /* packet with unicast indication but non-unicast recipient */
453         if (!is_valid_ether_addr(ethhdr->h_dest))
454                 return -EBADR;
455 
456         /* packet with broadcast/multicast sender address */
457         if (is_multicast_ether_addr(ethhdr->h_source))
458                 return -EBADR;
459 
460         /* not for me */
461         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
462                 return -EREMOTE;
463 
464         return 0;
465 }
466 
467 /**
468  * batadv_last_bonding_get() - Get last_bonding_candidate of orig_node
469  * @orig_node: originator node whose last bonding candidate should be retrieved
470  *
471  * Return: last bonding candidate of router or NULL if not found
472  *
473  * The object is returned with refcounter increased by 1.
474  */
475 static struct batadv_orig_ifinfo *
476 batadv_last_bonding_get(struct batadv_orig_node *orig_node)
477 {
478         struct batadv_orig_ifinfo *last_bonding_candidate;
479 
480         spin_lock_bh(&orig_node->neigh_list_lock);
481         last_bonding_candidate = orig_node->last_bonding_candidate;
482 
483         if (last_bonding_candidate)
484                 kref_get(&last_bonding_candidate->refcount);
485         spin_unlock_bh(&orig_node->neigh_list_lock);
486 
487         return last_bonding_candidate;
488 }
489 
490 /**
491  * batadv_last_bonding_replace() - Replace last_bonding_candidate of orig_node
492  * @orig_node: originator node whose bonding candidates should be replaced
493  * @new_candidate: new bonding candidate or NULL
494  */
495 static void
496 batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
497                             struct batadv_orig_ifinfo *new_candidate)
498 {
499         struct batadv_orig_ifinfo *old_candidate;
500 
501         spin_lock_bh(&orig_node->neigh_list_lock);
502         old_candidate = orig_node->last_bonding_candidate;
503 
504         if (new_candidate)
505                 kref_get(&new_candidate->refcount);
506         orig_node->last_bonding_candidate = new_candidate;
507         spin_unlock_bh(&orig_node->neigh_list_lock);
508 
509         batadv_orig_ifinfo_put(old_candidate);
510 }
511 
512 /**
513  * batadv_find_router() - find a suitable router for this originator
514  * @bat_priv: the bat priv with all the soft interface information
515  * @orig_node: the destination node
516  * @recv_if: pointer to interface this packet was received on
517  *
518  * Return: the router which should be used for this orig_node on
519  * this interface, or NULL if not available.
520  */
521 struct batadv_neigh_node *
522 batadv_find_router(struct batadv_priv *bat_priv,
523                    struct batadv_orig_node *orig_node,
524                    struct batadv_hard_iface *recv_if)
525 {
526         struct batadv_algo_ops *bao = bat_priv->algo_ops;
527         struct batadv_neigh_node *first_candidate_router = NULL;
528         struct batadv_neigh_node *next_candidate_router = NULL;
529         struct batadv_neigh_node *router, *cand_router = NULL;
530         struct batadv_neigh_node *last_cand_router = NULL;
531         struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
532         struct batadv_orig_ifinfo *next_candidate = NULL;
533         struct batadv_orig_ifinfo *last_candidate;
534         bool last_candidate_found = false;
535 
536         if (!orig_node)
537                 return NULL;
538 
539         router = batadv_orig_router_get(orig_node, recv_if);
540 
541         if (!router)
542                 return router;
543 
544         /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
545          * and if activated.
546          */
547         if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
548                 return router;
549 
550         /* bonding: loop through the list of possible routers found
551          * for the various outgoing interfaces and find a candidate after
552          * the last chosen bonding candidate (next_candidate). If no such
553          * router is found, use the first candidate found (the previously
554          * chosen bonding candidate might have been the last one in the list).
555          * If this can't be found either, return the previously chosen
556          * router - obviously there are no other candidates.
557          */
558         rcu_read_lock();
559         last_candidate = batadv_last_bonding_get(orig_node);
560         if (last_candidate)
561                 last_cand_router = rcu_dereference(last_candidate->router);
562 
563         hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
564                 /* acquire some structures and references ... */
565                 if (!kref_get_unless_zero(&cand->refcount))
566                         continue;
567 
568                 cand_router = rcu_dereference(cand->router);
569                 if (!cand_router)
570                         goto next;
571 
572                 if (!kref_get_unless_zero(&cand_router->refcount)) {
573                         cand_router = NULL;
574                         goto next;
575                 }
576 
577                 /* alternative candidate should be good enough to be
578                  * considered
579                  */
580                 if (!bao->neigh.is_similar_or_better(cand_router,
581                                                      cand->if_outgoing, router,
582                                                      recv_if))
583                         goto next;
584 
585                 /* don't use the same router twice */
586                 if (last_cand_router == cand_router)
587                         goto next;
588 
589                 /* mark the first possible candidate */
590                 if (!first_candidate) {
591                         kref_get(&cand_router->refcount);
592                         kref_get(&cand->refcount);
593                         first_candidate = cand;
594                         first_candidate_router = cand_router;
595                 }
596 
597                 /* check if the loop has already passed the previously selected
598                  * candidate ... this function should select the next candidate
599                  * AFTER the previously used bonding candidate.
600                  */
601                 if (!last_candidate || last_candidate_found) {
602                         next_candidate = cand;
603                         next_candidate_router = cand_router;
604                         break;
605                 }
606 
607                 if (last_candidate == cand)
608                         last_candidate_found = true;
609 next:
610                 /* free references */
611                 if (cand_router) {
612                         batadv_neigh_node_put(cand_router);
613                         cand_router = NULL;
614                 }
615                 batadv_orig_ifinfo_put(cand);
616         }
617         rcu_read_unlock();
618 
619         /* After finding candidates, handle the three cases:
620          * 1) there is a next candidate, use that
621          * 2) there is no next candidate, use the first of the list
622          * 3) there is no candidate at all, return the default router
623          */
624         if (next_candidate) {
625                 batadv_neigh_node_put(router);
626 
627                 kref_get(&next_candidate_router->refcount);
628                 router = next_candidate_router;
629                 batadv_last_bonding_replace(orig_node, next_candidate);
630         } else if (first_candidate) {
631                 batadv_neigh_node_put(router);
632 
633                 kref_get(&first_candidate_router->refcount);
634                 router = first_candidate_router;
635                 batadv_last_bonding_replace(orig_node, first_candidate);
636         } else {
637                 batadv_last_bonding_replace(orig_node, NULL);
638         }
639 
640         /* cleanup of candidates */
641         if (first_candidate) {
642                 batadv_neigh_node_put(first_candidate_router);
643                 batadv_orig_ifinfo_put(first_candidate);
644         }
645 
646         if (next_candidate) {
647                 batadv_neigh_node_put(next_candidate_router);
648                 batadv_orig_ifinfo_put(next_candidate);
649         }
650 
651         batadv_orig_ifinfo_put(last_candidate);
652 
653         return router;
654 }
655 
656 static int batadv_route_unicast_packet(struct sk_buff *skb,
657                                        struct batadv_hard_iface *recv_if)
658 {
659         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
660         struct batadv_orig_node *orig_node = NULL;
661         struct batadv_unicast_packet *unicast_packet;
662         struct ethhdr *ethhdr = eth_hdr(skb);
663         int res, hdr_len, ret = NET_RX_DROP;
664         unsigned int len;
665 
666         unicast_packet = (struct batadv_unicast_packet *)skb->data;
667 
668         /* TTL exceeded */
669         if (unicast_packet->ttl < 2) {
670                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
671                          ethhdr->h_source, unicast_packet->dest);
672                 goto free_skb;
673         }
674 
675         /* get routing information */
676         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
677 
678         if (!orig_node)
679                 goto free_skb;
680 
681         /* create a copy of the skb, if needed, to modify it. */
682         if (skb_cow(skb, ETH_HLEN) < 0)
683                 goto put_orig_node;
684 
685         /* decrement ttl */
686         unicast_packet = (struct batadv_unicast_packet *)skb->data;
687         unicast_packet->ttl--;
688 
689         switch (unicast_packet->packet_type) {
690         case BATADV_UNICAST_4ADDR:
691                 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
692                 break;
693         case BATADV_UNICAST:
694                 hdr_len = sizeof(struct batadv_unicast_packet);
695                 break;
696         default:
697                 /* other packet types not supported - yet */
698                 hdr_len = -1;
699                 break;
700         }
701 
702         if (hdr_len > 0)
703                 batadv_skb_set_priority(skb, hdr_len);
704 
705         len = skb->len;
706         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
707 
708         /* translate transmit result into receive result */
709         if (res == NET_XMIT_SUCCESS) {
710                 ret = NET_RX_SUCCESS;
711                 /* skb was transmitted and consumed */
712                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
713                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
714                                    len + ETH_HLEN);
715         }
716 
717         /* skb was consumed */
718         skb = NULL;
719 
720 put_orig_node:
721         batadv_orig_node_put(orig_node);
722 free_skb:
723         kfree_skb(skb);
724 
725         return ret;
726 }
727 
728 /**
729  * batadv_reroute_unicast_packet() - update the unicast header for re-routing
730  * @bat_priv: the bat priv with all the soft interface information
731  * @skb: unicast packet to process
732  * @unicast_packet: the unicast header to be updated
733  * @dst_addr: the payload destination
734  * @vid: VLAN identifier
735  *
736  * Search the translation table for dst_addr and update the unicast header with
737  * the new corresponding information (originator address where the destination
738  * client currently is and its known TTVN)
739  *
740  * Return: true if the packet header has been updated, false otherwise
741  */
742 static bool
743 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
744                               struct batadv_unicast_packet *unicast_packet,
745                               u8 *dst_addr, unsigned short vid)
746 {
747         struct batadv_orig_node *orig_node = NULL;
748         struct batadv_hard_iface *primary_if = NULL;
749         bool ret = false;
750         const u8 *orig_addr;
751         u8 orig_ttvn;
752 
753         if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
754                 primary_if = batadv_primary_if_get_selected(bat_priv);
755                 if (!primary_if)
756                         goto out;
757                 orig_addr = primary_if->net_dev->dev_addr;
758                 orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
759         } else {
760                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
761                                                      vid);
762                 if (!orig_node)
763                         goto out;
764 
765                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
766                         goto out;
767 
768                 orig_addr = orig_node->orig;
769                 orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
770         }
771 
772         /* update the packet header */
773         skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
774         ether_addr_copy(unicast_packet->dest, orig_addr);
775         unicast_packet->ttvn = orig_ttvn;
776         skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
777 
778         ret = true;
779 out:
780         batadv_hardif_put(primary_if);
781         batadv_orig_node_put(orig_node);
782 
783         return ret;
784 }
785 
786 static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
787                                       struct sk_buff *skb, int hdr_len)
788 {
789         struct batadv_unicast_packet *unicast_packet;
790         struct batadv_hard_iface *primary_if;
791         struct batadv_orig_node *orig_node;
792         u8 curr_ttvn, old_ttvn;
793         struct ethhdr *ethhdr;
794         unsigned short vid;
795         int is_old_ttvn;
796 
797         /* check if there is enough data before accessing it */
798         if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
799                 return false;
800 
801         /* create a copy of the skb (in case of for re-routing) to modify it. */
802         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
803                 return false;
804 
805         unicast_packet = (struct batadv_unicast_packet *)skb->data;
806         vid = batadv_get_vid(skb, hdr_len);
807         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
808 
809         /* do not reroute multicast frames in a unicast header */
810         if (is_multicast_ether_addr(ethhdr->h_dest))
811                 return true;
812 
813         /* check if the destination client was served by this node and it is now
814          * roaming. In this case, it means that the node has got a ROAM_ADV
815          * message and that it knows the new destination in the mesh to re-route
816          * the packet to
817          */
818         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
819                 if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
820                                                   ethhdr->h_dest, vid))
821                         batadv_dbg_ratelimited(BATADV_DBG_TT,
822                                                bat_priv,
823                                                "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
824                                                unicast_packet->dest,
825                                                ethhdr->h_dest);
826                 /* at this point the mesh destination should have been
827                  * substituted with the originator address found in the global
828                  * table. If not, let the packet go untouched anyway because
829                  * there is nothing the node can do
830                  */
831                 return true;
832         }
833 
834         /* retrieve the TTVN known by this node for the packet destination. This
835          * value is used later to check if the node which sent (or re-routed
836          * last time) the packet had an updated information or not
837          */
838         curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
839         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
840                 orig_node = batadv_orig_hash_find(bat_priv,
841                                                   unicast_packet->dest);
842                 /* if it is not possible to find the orig_node representing the
843                  * destination, the packet can immediately be dropped as it will
844                  * not be possible to deliver it
845                  */
846                 if (!orig_node)
847                         return false;
848 
849                 curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
850                 batadv_orig_node_put(orig_node);
851         }
852 
853         /* check if the TTVN contained in the packet is fresher than what the
854          * node knows
855          */
856         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
857         if (!is_old_ttvn)
858                 return true;
859 
860         old_ttvn = unicast_packet->ttvn;
861         /* the packet was forged based on outdated network information. Its
862          * destination can possibly be updated and forwarded towards the new
863          * target host
864          */
865         if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
866                                           ethhdr->h_dest, vid)) {
867                 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
868                                        "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
869                                        unicast_packet->dest, ethhdr->h_dest,
870                                        old_ttvn, curr_ttvn);
871                 return true;
872         }
873 
874         /* the packet has not been re-routed: either the destination is
875          * currently served by this node or there is no destination at all and
876          * it is possible to drop the packet
877          */
878         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
879                 return false;
880 
881         /* update the header in order to let the packet be delivered to this
882          * node's soft interface
883          */
884         primary_if = batadv_primary_if_get_selected(bat_priv);
885         if (!primary_if)
886                 return false;
887 
888         /* update the packet header */
889         skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
890         ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
891         unicast_packet->ttvn = curr_ttvn;
892         skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
893 
894         batadv_hardif_put(primary_if);
895 
896         return true;
897 }
898 
899 /**
900  * batadv_recv_unhandled_unicast_packet() - receive and process packets which
901  *      are in the unicast number space but not yet known to the implementation
902  * @skb: unicast tvlv packet to process
903  * @recv_if: pointer to interface this packet was received on
904  *
905  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
906  * otherwise.
907  */
908 int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
909                                          struct batadv_hard_iface *recv_if)
910 {
911         struct batadv_unicast_packet *unicast_packet;
912         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
913         int check, hdr_size = sizeof(*unicast_packet);
914 
915         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
916         if (check < 0)
917                 goto free_skb;
918 
919         /* we don't know about this type, drop it. */
920         unicast_packet = (struct batadv_unicast_packet *)skb->data;
921         if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
922                 goto free_skb;
923 
924         return batadv_route_unicast_packet(skb, recv_if);
925 
926 free_skb:
927         kfree_skb(skb);
928         return NET_RX_DROP;
929 }
930 
931 /**
932  * batadv_recv_unicast_packet() - Process incoming unicast packet
933  * @skb: incoming packet buffer
934  * @recv_if: incoming hard interface
935  *
936  * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
937  */
938 int batadv_recv_unicast_packet(struct sk_buff *skb,
939                                struct batadv_hard_iface *recv_if)
940 {
941         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
942         struct batadv_unicast_packet *unicast_packet;
943         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
944         u8 *orig_addr, *orig_addr_gw;
945         struct batadv_orig_node *orig_node = NULL, *orig_node_gw = NULL;
946         int check, hdr_size = sizeof(*unicast_packet);
947         enum batadv_subtype subtype;
948         int ret = NET_RX_DROP;
949         bool is4addr, is_gw;
950 
951         unicast_packet = (struct batadv_unicast_packet *)skb->data;
952         is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
953         /* the caller function should have already pulled 2 bytes */
954         if (is4addr)
955                 hdr_size = sizeof(*unicast_4addr_packet);
956 
957         /* function returns -EREMOTE for promiscuous packets */
958         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
959 
960         /* Even though the packet is not for us, we might save it to use for
961          * decoding a later received coded packet
962          */
963         if (check == -EREMOTE)
964                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
965 
966         if (check < 0)
967                 goto free_skb;
968         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
969                 goto free_skb;
970 
971         unicast_packet = (struct batadv_unicast_packet *)skb->data;
972 
973         /* packet for me */
974         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
975                 /* If this is a unicast packet from another backgone gw,
976                  * drop it.
977                  */
978                 orig_addr_gw = eth_hdr(skb)->h_source;
979                 orig_node_gw = batadv_orig_hash_find(bat_priv, orig_addr_gw);
980                 if (orig_node_gw) {
981                         is_gw = batadv_bla_is_backbone_gw(skb, orig_node_gw,
982                                                           hdr_size);
983                         batadv_orig_node_put(orig_node_gw);
984                         if (is_gw) {
985                                 batadv_dbg(BATADV_DBG_BLA, bat_priv,
986                                            "%s(): Dropped unicast pkt received from another backbone gw %pM.\n",
987                                            __func__, orig_addr_gw);
988                                 goto free_skb;
989                         }
990                 }
991 
992                 if (is4addr) {
993                         unicast_4addr_packet =
994                                 (struct batadv_unicast_4addr_packet *)skb->data;
995                         subtype = unicast_4addr_packet->subtype;
996                         batadv_dat_inc_counter(bat_priv, subtype);
997 
998                         /* Only payload data should be considered for speedy
999                          * join. For example, DAT also uses unicast 4addr
1000                          * types, but those packets should not be considered
1001                          * for speedy join, since the clients do not actually
1002                          * reside at the sending originator.
1003                          */
1004                         if (subtype == BATADV_P_DATA) {
1005                                 orig_addr = unicast_4addr_packet->src;
1006                                 orig_node = batadv_orig_hash_find(bat_priv,
1007                                                                   orig_addr);
1008                         }
1009                 }
1010 
1011                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
1012                                                           hdr_size))
1013                         goto rx_success;
1014                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
1015                                                         hdr_size))
1016                         goto rx_success;
1017 
1018                 batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size);
1019 
1020                 batadv_interface_rx(recv_if->soft_iface, skb, hdr_size,
1021                                     orig_node);
1022 
1023 rx_success:
1024                 batadv_orig_node_put(orig_node);
1025 
1026                 return NET_RX_SUCCESS;
1027         }
1028 
1029         ret = batadv_route_unicast_packet(skb, recv_if);
1030         /* skb was consumed */
1031         skb = NULL;
1032 
1033 free_skb:
1034         kfree_skb(skb);
1035 
1036         return ret;
1037 }
1038 
1039 /**
1040  * batadv_recv_unicast_tvlv() - receive and process unicast tvlv packets
1041  * @skb: unicast tvlv packet to process
1042  * @recv_if: pointer to interface this packet was received on
1043  *
1044  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1045  * otherwise.
1046  */
1047 int batadv_recv_unicast_tvlv(struct sk_buff *skb,
1048                              struct batadv_hard_iface *recv_if)
1049 {
1050         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1051         struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
1052         unsigned char *tvlv_buff;
1053         u16 tvlv_buff_len;
1054         int hdr_size = sizeof(*unicast_tvlv_packet);
1055         int ret = NET_RX_DROP;
1056 
1057         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1058                 goto free_skb;
1059 
1060         /* the header is likely to be modified while forwarding */
1061         if (skb_cow(skb, hdr_size) < 0)
1062                 goto free_skb;
1063 
1064         /* packet needs to be linearized to access the tvlv content */
1065         if (skb_linearize(skb) < 0)
1066                 goto free_skb;
1067 
1068         unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1069 
1070         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1071         tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1072 
1073         if (tvlv_buff_len > skb->len - hdr_size)
1074                 goto free_skb;
1075 
1076         ret = batadv_tvlv_containers_process(bat_priv, BATADV_UNICAST_TVLV,
1077                                              NULL, skb, tvlv_buff,
1078                                              tvlv_buff_len);
1079 
1080         if (ret != NET_RX_SUCCESS) {
1081                 ret = batadv_route_unicast_packet(skb, recv_if);
1082                 /* skb was consumed */
1083                 skb = NULL;
1084         }
1085 
1086 free_skb:
1087         kfree_skb(skb);
1088 
1089         return ret;
1090 }
1091 
1092 /**
1093  * batadv_recv_frag_packet() - process received fragment
1094  * @skb: the received fragment
1095  * @recv_if: interface that the skb is received on
1096  *
1097  * This function does one of the three following things: 1) Forward fragment, if
1098  * the assembled packet will exceed our MTU; 2) Buffer fragment, if we still
1099  * lack further fragments; 3) Merge fragments, if we have all needed parts.
1100  *
1101  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1102  */
1103 int batadv_recv_frag_packet(struct sk_buff *skb,
1104                             struct batadv_hard_iface *recv_if)
1105 {
1106         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1107         struct batadv_orig_node *orig_node_src = NULL;
1108         struct batadv_frag_packet *frag_packet;
1109         int ret = NET_RX_DROP;
1110 
1111         if (batadv_check_unicast_packet(bat_priv, skb,
1112                                         sizeof(*frag_packet)) < 0)
1113                 goto free_skb;
1114 
1115         frag_packet = (struct batadv_frag_packet *)skb->data;
1116         orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
1117         if (!orig_node_src)
1118                 goto free_skb;
1119 
1120         skb->priority = frag_packet->priority + 256;
1121 
1122         /* Route the fragment if it is not for us and too big to be merged. */
1123         if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
1124             batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1125                 /* skb was consumed */
1126                 skb = NULL;
1127                 ret = NET_RX_SUCCESS;
1128                 goto put_orig_node;
1129         }
1130 
1131         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1132         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
1133 
1134         /* Add fragment to buffer and merge if possible. */
1135         if (!batadv_frag_skb_buffer(&skb, orig_node_src))
1136                 goto put_orig_node;
1137 
1138         /* Deliver merged packet to the appropriate handler, if it was
1139          * merged
1140          */
1141         if (skb) {
1142                 batadv_batman_skb_recv(skb, recv_if->net_dev,
1143                                        &recv_if->batman_adv_ptype, NULL);
1144                 /* skb was consumed */
1145                 skb = NULL;
1146         }
1147 
1148         ret = NET_RX_SUCCESS;
1149 
1150 put_orig_node:
1151         batadv_orig_node_put(orig_node_src);
1152 free_skb:
1153         kfree_skb(skb);
1154 
1155         return ret;
1156 }
1157 
1158 /**
1159  * batadv_recv_bcast_packet() - Process incoming broadcast packet
1160  * @skb: incoming packet buffer
1161  * @recv_if: incoming hard interface
1162  *
1163  * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
1164  */
1165 int batadv_recv_bcast_packet(struct sk_buff *skb,
1166                              struct batadv_hard_iface *recv_if)
1167 {
1168         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1169         struct batadv_orig_node *orig_node = NULL;
1170         struct batadv_bcast_packet *bcast_packet;
1171         struct ethhdr *ethhdr;
1172         int hdr_size = sizeof(*bcast_packet);
1173         s32 seq_diff;
1174         u32 seqno;
1175         int ret;
1176 
1177         /* drop packet if it has not necessary minimum size */
1178         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1179                 goto free_skb;
1180 
1181         ethhdr = eth_hdr(skb);
1182 
1183         /* packet with broadcast indication but unicast recipient */
1184         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1185                 goto free_skb;
1186 
1187         /* packet with broadcast/multicast sender address */
1188         if (is_multicast_ether_addr(ethhdr->h_source))
1189                 goto free_skb;
1190 
1191         /* ignore broadcasts sent by myself */
1192         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1193                 goto free_skb;
1194 
1195         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1196 
1197         /* ignore broadcasts originated by myself */
1198         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1199                 goto free_skb;
1200 
1201         if (bcast_packet->ttl-- < 2)
1202                 goto free_skb;
1203 
1204         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1205 
1206         if (!orig_node)
1207                 goto free_skb;
1208 
1209         spin_lock_bh(&orig_node->bcast_seqno_lock);
1210 
1211         seqno = ntohl(bcast_packet->seqno);
1212         /* check whether the packet is a duplicate */
1213         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1214                             seqno))
1215                 goto spin_unlock;
1216 
1217         seq_diff = seqno - orig_node->last_bcast_seqno;
1218 
1219         /* check whether the packet is old and the host just restarted. */
1220         if (batadv_window_protected(bat_priv, seq_diff,
1221                                     BATADV_BCAST_MAX_AGE,
1222                                     &orig_node->bcast_seqno_reset, NULL))
1223                 goto spin_unlock;
1224 
1225         /* mark broadcast in flood history, update window position
1226          * if required.
1227          */
1228         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1229                 orig_node->last_bcast_seqno = seqno;
1230 
1231         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1232 
1233         /* check whether this has been sent by another originator before */
1234         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1235                 goto free_skb;
1236 
1237         batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1238 
1239         /* rebroadcast packet */
1240         ret = batadv_forw_bcast_packet(bat_priv, skb, 0, false);
1241         if (ret == NETDEV_TX_BUSY)
1242                 goto free_skb;
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         batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size);
1256 
1257         /* broadcast for me */
1258         batadv_interface_rx(recv_if->soft_iface, skb, hdr_size, orig_node);
1259 
1260 rx_success:
1261         ret = NET_RX_SUCCESS;
1262         goto out;
1263 
1264 spin_unlock:
1265         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1266 free_skb:
1267         kfree_skb(skb);
1268         ret = NET_RX_DROP;
1269 out:
1270         batadv_orig_node_put(orig_node);
1271         return ret;
1272 }
1273 
1274 #ifdef CONFIG_BATMAN_ADV_MCAST
1275 /**
1276  * batadv_recv_mcast_packet() - process received batman-adv multicast packet
1277  * @skb: the received batman-adv multicast packet
1278  * @recv_if: interface that the skb is received on
1279  *
1280  * Parses the given, received batman-adv multicast packet. Depending on the
1281  * contents of its TVLV forwards it and/or decapsulates it to hand it to the
1282  * soft interface.
1283  *
1284  * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1285  */
1286 int batadv_recv_mcast_packet(struct sk_buff *skb,
1287                              struct batadv_hard_iface *recv_if)
1288 {
1289         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1290         struct batadv_mcast_packet *mcast_packet;
1291         int hdr_size = sizeof(*mcast_packet);
1292         unsigned char *tvlv_buff;
1293         int ret = NET_RX_DROP;
1294         u16 tvlv_buff_len;
1295 
1296         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1297                 goto free_skb;
1298 
1299         /* create a copy of the skb, if needed, to modify it. */
1300         if (skb_cow(skb, ETH_HLEN) < 0)
1301                 goto free_skb;
1302 
1303         /* packet needs to be linearized to access the tvlv content */
1304         if (skb_linearize(skb) < 0)
1305                 goto free_skb;
1306 
1307         mcast_packet = (struct batadv_mcast_packet *)skb->data;
1308         if (mcast_packet->ttl-- < 2)
1309                 goto free_skb;
1310 
1311         tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1312         tvlv_buff_len = ntohs(mcast_packet->tvlv_len);
1313 
1314         if (tvlv_buff_len > skb->len - hdr_size)
1315                 goto free_skb;
1316 
1317         ret = batadv_tvlv_containers_process(bat_priv, BATADV_MCAST, NULL, skb,
1318                                              tvlv_buff, tvlv_buff_len);
1319         if (ret >= 0) {
1320                 batadv_inc_counter(bat_priv, BATADV_CNT_MCAST_RX);
1321                 batadv_add_counter(bat_priv, BATADV_CNT_MCAST_RX_BYTES,
1322                                    skb->len + ETH_HLEN);
1323         }
1324 
1325         hdr_size += tvlv_buff_len;
1326 
1327         if (ret == NET_RX_SUCCESS && (skb->len - hdr_size >= ETH_HLEN)) {
1328                 batadv_inc_counter(bat_priv, BATADV_CNT_MCAST_RX_LOCAL);
1329                 batadv_add_counter(bat_priv, BATADV_CNT_MCAST_RX_LOCAL_BYTES,
1330                                    skb->len - hdr_size);
1331 
1332                 batadv_interface_rx(bat_priv->soft_iface, skb, hdr_size, NULL);
1333                 /* skb was consumed */
1334                 skb = NULL;
1335         }
1336 
1337 free_skb:
1338         kfree_skb(skb);
1339 
1340         return ret;
1341 }
1342 #endif /* CONFIG_BATMAN_ADV_MCAST */
1343 

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