Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[~shefty/rdma-dev.git] / net / batman-adv / routing.c
1 /* Copyright (C) 2007-2013 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, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA
18  */
19
20 #include "main.h"
21 #include "routing.h"
22 #include "send.h"
23 #include "soft-interface.h"
24 #include "hard-interface.h"
25 #include "icmp_socket.h"
26 #include "translation-table.h"
27 #include "originator.h"
28 #include "vis.h"
29 #include "unicast.h"
30 #include "bridge_loop_avoidance.h"
31 #include "distributed-arp-table.h"
32 #include "network-coding.h"
33
34 static int batadv_route_unicast_packet(struct sk_buff *skb,
35                                        struct batadv_hard_iface *recv_if);
36
37 void batadv_slide_own_bcast_window(struct batadv_hard_iface *hard_iface)
38 {
39         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
40         struct batadv_hashtable *hash = bat_priv->orig_hash;
41         struct hlist_head *head;
42         struct batadv_orig_node *orig_node;
43         unsigned long *word;
44         uint32_t i;
45         size_t word_index;
46         uint8_t *w;
47
48         for (i = 0; i < hash->size; i++) {
49                 head = &hash->table[i];
50
51                 rcu_read_lock();
52                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
53                         spin_lock_bh(&orig_node->ogm_cnt_lock);
54                         word_index = hard_iface->if_num * BATADV_NUM_WORDS;
55                         word = &(orig_node->bcast_own[word_index]);
56
57                         batadv_bit_get_packet(bat_priv, word, 1, 0);
58                         w = &orig_node->bcast_own_sum[hard_iface->if_num];
59                         *w = bitmap_weight(word, BATADV_TQ_LOCAL_WINDOW_SIZE);
60                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
61                 }
62                 rcu_read_unlock();
63         }
64 }
65
66 static void _batadv_update_route(struct batadv_priv *bat_priv,
67                                  struct batadv_orig_node *orig_node,
68                                  struct batadv_neigh_node *neigh_node)
69 {
70         struct batadv_neigh_node *curr_router;
71
72         curr_router = batadv_orig_node_get_router(orig_node);
73
74         /* route deleted */
75         if ((curr_router) && (!neigh_node)) {
76                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
77                            "Deleting route towards: %pM\n", orig_node->orig);
78                 batadv_tt_global_del_orig(bat_priv, orig_node,
79                                           "Deleted route towards originator");
80
81         /* route added */
82         } else if ((!curr_router) && (neigh_node)) {
83                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
84                            "Adding route towards: %pM (via %pM)\n",
85                            orig_node->orig, neigh_node->addr);
86         /* route changed */
87         } else if (neigh_node && curr_router) {
88                 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
89                            "Changing route towards: %pM (now via %pM - was via %pM)\n",
90                            orig_node->orig, neigh_node->addr,
91                            curr_router->addr);
92         }
93
94         if (curr_router)
95                 batadv_neigh_node_free_ref(curr_router);
96
97         /* increase refcount of new best neighbor */
98         if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
99                 neigh_node = NULL;
100
101         spin_lock_bh(&orig_node->neigh_list_lock);
102         rcu_assign_pointer(orig_node->router, neigh_node);
103         spin_unlock_bh(&orig_node->neigh_list_lock);
104
105         /* decrease refcount of previous best neighbor */
106         if (curr_router)
107                 batadv_neigh_node_free_ref(curr_router);
108 }
109
110 void batadv_update_route(struct batadv_priv *bat_priv,
111                          struct batadv_orig_node *orig_node,
112                          struct batadv_neigh_node *neigh_node)
113 {
114         struct batadv_neigh_node *router = NULL;
115
116         if (!orig_node)
117                 goto out;
118
119         router = batadv_orig_node_get_router(orig_node);
120
121         if (router != neigh_node)
122                 _batadv_update_route(bat_priv, orig_node, neigh_node);
123
124 out:
125         if (router)
126                 batadv_neigh_node_free_ref(router);
127 }
128
129 /* caller must hold the neigh_list_lock */
130 void batadv_bonding_candidate_del(struct batadv_orig_node *orig_node,
131                                   struct batadv_neigh_node *neigh_node)
132 {
133         /* this neighbor is not part of our candidate list */
134         if (list_empty(&neigh_node->bonding_list))
135                 goto out;
136
137         list_del_rcu(&neigh_node->bonding_list);
138         INIT_LIST_HEAD(&neigh_node->bonding_list);
139         batadv_neigh_node_free_ref(neigh_node);
140         atomic_dec(&orig_node->bond_candidates);
141
142 out:
143         return;
144 }
145
146 void batadv_bonding_candidate_add(struct batadv_orig_node *orig_node,
147                                   struct batadv_neigh_node *neigh_node)
148 {
149         struct batadv_neigh_node *tmp_neigh_node, *router = NULL;
150         uint8_t interference_candidate = 0;
151
152         spin_lock_bh(&orig_node->neigh_list_lock);
153
154         /* only consider if it has the same primary address ...  */
155         if (!batadv_compare_eth(orig_node->orig,
156                                 neigh_node->orig_node->primary_addr))
157                 goto candidate_del;
158
159         router = batadv_orig_node_get_router(orig_node);
160         if (!router)
161                 goto candidate_del;
162
163         /* ... and is good enough to be considered */
164         if (neigh_node->tq_avg < router->tq_avg - BATADV_BONDING_TQ_THRESHOLD)
165                 goto candidate_del;
166
167         /* check if we have another candidate with the same mac address or
168          * interface. If we do, we won't select this candidate because of
169          * possible interference.
170          */
171         hlist_for_each_entry_rcu(tmp_neigh_node,
172                                  &orig_node->neigh_list, list) {
173                 if (tmp_neigh_node == neigh_node)
174                         continue;
175
176                 /* we only care if the other candidate is even
177                  * considered as candidate.
178                  */
179                 if (list_empty(&tmp_neigh_node->bonding_list))
180                         continue;
181
182                 if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
183                     (batadv_compare_eth(neigh_node->addr,
184                                         tmp_neigh_node->addr))) {
185                         interference_candidate = 1;
186                         break;
187                 }
188         }
189
190         /* don't care further if it is an interference candidate */
191         if (interference_candidate)
192                 goto candidate_del;
193
194         /* this neighbor already is part of our candidate list */
195         if (!list_empty(&neigh_node->bonding_list))
196                 goto out;
197
198         if (!atomic_inc_not_zero(&neigh_node->refcount))
199                 goto out;
200
201         list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
202         atomic_inc(&orig_node->bond_candidates);
203         goto out;
204
205 candidate_del:
206         batadv_bonding_candidate_del(orig_node, neigh_node);
207
208 out:
209         spin_unlock_bh(&orig_node->neigh_list_lock);
210
211         if (router)
212                 batadv_neigh_node_free_ref(router);
213 }
214
215 /* copy primary address for bonding */
216 void
217 batadv_bonding_save_primary(const struct batadv_orig_node *orig_node,
218                             struct batadv_orig_node *orig_neigh_node,
219                             const struct batadv_ogm_packet *batman_ogm_packet)
220 {
221         if (!(batman_ogm_packet->flags & BATADV_PRIMARIES_FIRST_HOP))
222                 return;
223
224         memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
225 }
226
227 /* checks whether the host restarted and is in the protection time.
228  * returns:
229  *  0 if the packet is to be accepted
230  *  1 if the packet is to be ignored.
231  */
232 int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
233                             unsigned long *last_reset)
234 {
235         if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
236             seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
237                 if (!batadv_has_timed_out(*last_reset,
238                                           BATADV_RESET_PROTECTION_MS))
239                         return 1;
240
241                 *last_reset = jiffies;
242                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
243                            "old packet received, start protection\n");
244         }
245
246         return 0;
247 }
248
249 bool batadv_check_management_packet(struct sk_buff *skb,
250                                     struct batadv_hard_iface *hard_iface,
251                                     int header_len)
252 {
253         struct ethhdr *ethhdr;
254
255         /* drop packet if it has not necessary minimum size */
256         if (unlikely(!pskb_may_pull(skb, header_len)))
257                 return false;
258
259         ethhdr = (struct ethhdr *)skb_mac_header(skb);
260
261         /* packet with broadcast indication but unicast recipient */
262         if (!is_broadcast_ether_addr(ethhdr->h_dest))
263                 return false;
264
265         /* packet with broadcast sender address */
266         if (is_broadcast_ether_addr(ethhdr->h_source))
267                 return false;
268
269         /* create a copy of the skb, if needed, to modify it. */
270         if (skb_cow(skb, 0) < 0)
271                 return false;
272
273         /* keep skb linear */
274         if (skb_linearize(skb) < 0)
275                 return false;
276
277         return true;
278 }
279
280 static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
281                                       struct sk_buff *skb, size_t icmp_len)
282 {
283         struct batadv_hard_iface *primary_if = NULL;
284         struct batadv_orig_node *orig_node = NULL;
285         struct batadv_icmp_packet_rr *icmp_packet;
286         int ret = NET_RX_DROP;
287
288         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
289
290         /* add data to device queue */
291         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
292                 batadv_socket_receive_packet(icmp_packet, icmp_len);
293                 goto out;
294         }
295
296         primary_if = batadv_primary_if_get_selected(bat_priv);
297         if (!primary_if)
298                 goto out;
299
300         /* answer echo request (ping) */
301         /* get routing information */
302         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
303         if (!orig_node)
304                 goto out;
305
306         /* create a copy of the skb, if needed, to modify it. */
307         if (skb_cow(skb, ETH_HLEN) < 0)
308                 goto out;
309
310         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
311
312         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
313         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
314         icmp_packet->msg_type = BATADV_ECHO_REPLY;
315         icmp_packet->header.ttl = BATADV_TTL;
316
317         if (batadv_send_skb_to_orig(skb, orig_node, NULL))
318                 ret = NET_RX_SUCCESS;
319
320 out:
321         if (primary_if)
322                 batadv_hardif_free_ref(primary_if);
323         if (orig_node)
324                 batadv_orig_node_free_ref(orig_node);
325         return ret;
326 }
327
328 static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
329                                          struct sk_buff *skb)
330 {
331         struct batadv_hard_iface *primary_if = NULL;
332         struct batadv_orig_node *orig_node = NULL;
333         struct batadv_icmp_packet *icmp_packet;
334         int ret = NET_RX_DROP;
335
336         icmp_packet = (struct batadv_icmp_packet *)skb->data;
337
338         /* send TTL exceeded if packet is an echo request (traceroute) */
339         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
340                 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
341                          icmp_packet->orig, icmp_packet->dst);
342                 goto out;
343         }
344
345         primary_if = batadv_primary_if_get_selected(bat_priv);
346         if (!primary_if)
347                 goto out;
348
349         /* get routing information */
350         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
351         if (!orig_node)
352                 goto out;
353
354         /* create a copy of the skb, if needed, to modify it. */
355         if (skb_cow(skb, ETH_HLEN) < 0)
356                 goto out;
357
358         icmp_packet = (struct batadv_icmp_packet *)skb->data;
359
360         memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
361         memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
362         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
363         icmp_packet->header.ttl = BATADV_TTL;
364
365         if (batadv_send_skb_to_orig(skb, orig_node, NULL))
366                 ret = NET_RX_SUCCESS;
367
368 out:
369         if (primary_if)
370                 batadv_hardif_free_ref(primary_if);
371         if (orig_node)
372                 batadv_orig_node_free_ref(orig_node);
373         return ret;
374 }
375
376
377 int batadv_recv_icmp_packet(struct sk_buff *skb,
378                             struct batadv_hard_iface *recv_if)
379 {
380         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
381         struct batadv_icmp_packet_rr *icmp_packet;
382         struct ethhdr *ethhdr;
383         struct batadv_orig_node *orig_node = NULL;
384         int hdr_size = sizeof(struct batadv_icmp_packet);
385         int ret = NET_RX_DROP;
386
387         /* we truncate all incoming icmp packets if they don't match our size */
388         if (skb->len >= sizeof(struct batadv_icmp_packet_rr))
389                 hdr_size = sizeof(struct batadv_icmp_packet_rr);
390
391         /* drop packet if it has not necessary minimum size */
392         if (unlikely(!pskb_may_pull(skb, hdr_size)))
393                 goto out;
394
395         ethhdr = (struct ethhdr *)skb_mac_header(skb);
396
397         /* packet with unicast indication but broadcast recipient */
398         if (is_broadcast_ether_addr(ethhdr->h_dest))
399                 goto out;
400
401         /* packet with broadcast sender address */
402         if (is_broadcast_ether_addr(ethhdr->h_source))
403                 goto out;
404
405         /* not for me */
406         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
407                 goto out;
408
409         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
410
411         /* add record route information if not full */
412         if ((hdr_size == sizeof(struct batadv_icmp_packet_rr)) &&
413             (icmp_packet->rr_cur < BATADV_RR_LEN)) {
414                 memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
415                        ethhdr->h_dest, ETH_ALEN);
416                 icmp_packet->rr_cur++;
417         }
418
419         /* packet for me */
420         if (batadv_is_my_mac(bat_priv, icmp_packet->dst))
421                 return batadv_recv_my_icmp_packet(bat_priv, skb, hdr_size);
422
423         /* TTL exceeded */
424         if (icmp_packet->header.ttl < 2)
425                 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
426
427         /* get routing information */
428         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->dst);
429         if (!orig_node)
430                 goto out;
431
432         /* create a copy of the skb, if needed, to modify it. */
433         if (skb_cow(skb, ETH_HLEN) < 0)
434                 goto out;
435
436         icmp_packet = (struct batadv_icmp_packet_rr *)skb->data;
437
438         /* decrement ttl */
439         icmp_packet->header.ttl--;
440
441         /* route it */
442         if (batadv_send_skb_to_orig(skb, orig_node, recv_if))
443                 ret = NET_RX_SUCCESS;
444
445 out:
446         if (orig_node)
447                 batadv_orig_node_free_ref(orig_node);
448         return ret;
449 }
450
451 /* In the bonding case, send the packets in a round
452  * robin fashion over the remaining interfaces.
453  *
454  * This method rotates the bonding list and increases the
455  * returned router's refcount.
456  */
457 static struct batadv_neigh_node *
458 batadv_find_bond_router(struct batadv_orig_node *primary_orig,
459                         const struct batadv_hard_iface *recv_if)
460 {
461         struct batadv_neigh_node *tmp_neigh_node;
462         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
463
464         rcu_read_lock();
465         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
466                                 bonding_list) {
467                 if (!first_candidate)
468                         first_candidate = tmp_neigh_node;
469
470                 /* recv_if == NULL on the first node. */
471                 if (tmp_neigh_node->if_incoming == recv_if)
472                         continue;
473
474                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
475                         continue;
476
477                 router = tmp_neigh_node;
478                 break;
479         }
480
481         /* use the first candidate if nothing was found. */
482         if (!router && first_candidate &&
483             atomic_inc_not_zero(&first_candidate->refcount))
484                 router = first_candidate;
485
486         if (!router)
487                 goto out;
488
489         /* selected should point to the next element
490          * after the current router
491          */
492         spin_lock_bh(&primary_orig->neigh_list_lock);
493         /* this is a list_move(), which unfortunately
494          * does not exist as rcu version
495          */
496         list_del_rcu(&primary_orig->bond_list);
497         list_add_rcu(&primary_orig->bond_list,
498                      &router->bonding_list);
499         spin_unlock_bh(&primary_orig->neigh_list_lock);
500
501 out:
502         rcu_read_unlock();
503         return router;
504 }
505
506 /* Interface Alternating: Use the best of the
507  * remaining candidates which are not using
508  * this interface.
509  *
510  * Increases the returned router's refcount
511  */
512 static struct batadv_neigh_node *
513 batadv_find_ifalter_router(struct batadv_orig_node *primary_orig,
514                            const struct batadv_hard_iface *recv_if)
515 {
516         struct batadv_neigh_node *tmp_neigh_node;
517         struct batadv_neigh_node *router = NULL, *first_candidate = NULL;
518
519         rcu_read_lock();
520         list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
521                                 bonding_list) {
522                 if (!first_candidate)
523                         first_candidate = tmp_neigh_node;
524
525                 /* recv_if == NULL on the first node. */
526                 if (tmp_neigh_node->if_incoming == recv_if)
527                         continue;
528
529                 if (router && tmp_neigh_node->tq_avg <= router->tq_avg)
530                         continue;
531
532                 if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
533                         continue;
534
535                 /* decrement refcount of previously selected router */
536                 if (router)
537                         batadv_neigh_node_free_ref(router);
538
539                 /* we found a better router (or at least one valid router) */
540                 router = tmp_neigh_node;
541         }
542
543         /* use the first candidate if nothing was found. */
544         if (!router && first_candidate &&
545             atomic_inc_not_zero(&first_candidate->refcount))
546                 router = first_candidate;
547
548         rcu_read_unlock();
549         return router;
550 }
551
552 /**
553  * batadv_check_unicast_packet - Check for malformed unicast packets
554  * @bat_priv: the bat priv with all the soft interface information
555  * @skb: packet to check
556  * @hdr_size: size of header to pull
557  *
558  * Check for short header and bad addresses in given packet. Returns negative
559  * value when check fails and 0 otherwise. The negative value depends on the
560  * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
561  * and -EREMOTE for non-local (other host) destination.
562  */
563 static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
564                                        struct sk_buff *skb, int hdr_size)
565 {
566         struct ethhdr *ethhdr;
567
568         /* drop packet if it has not necessary minimum size */
569         if (unlikely(!pskb_may_pull(skb, hdr_size)))
570                 return -ENODATA;
571
572         ethhdr = (struct ethhdr *)skb_mac_header(skb);
573
574         /* packet with unicast indication but broadcast recipient */
575         if (is_broadcast_ether_addr(ethhdr->h_dest))
576                 return -EBADR;
577
578         /* packet with broadcast sender address */
579         if (is_broadcast_ether_addr(ethhdr->h_source))
580                 return -EBADR;
581
582         /* not for me */
583         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
584                 return -EREMOTE;
585
586         return 0;
587 }
588
589 int batadv_recv_tt_query(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
590 {
591         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
592         struct batadv_tt_query_packet *tt_query;
593         uint16_t tt_size;
594         int hdr_size = sizeof(*tt_query);
595         char tt_flag;
596         size_t packet_size;
597
598         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
599                 return NET_RX_DROP;
600
601         /* I could need to modify it */
602         if (skb_cow(skb, sizeof(struct batadv_tt_query_packet)) < 0)
603                 goto out;
604
605         tt_query = (struct batadv_tt_query_packet *)skb->data;
606
607         switch (tt_query->flags & BATADV_TT_QUERY_TYPE_MASK) {
608         case BATADV_TT_REQUEST:
609                 batadv_inc_counter(bat_priv, BATADV_CNT_TT_REQUEST_RX);
610
611                 /* If we cannot provide an answer the tt_request is
612                  * forwarded
613                  */
614                 if (!batadv_send_tt_response(bat_priv, tt_query)) {
615                         if (tt_query->flags & BATADV_TT_FULL_TABLE)
616                                 tt_flag = 'F';
617                         else
618                                 tt_flag = '.';
619
620                         batadv_dbg(BATADV_DBG_TT, bat_priv,
621                                    "Routing TT_REQUEST to %pM [%c]\n",
622                                    tt_query->dst,
623                                    tt_flag);
624                         return batadv_route_unicast_packet(skb, recv_if);
625                 }
626                 break;
627         case BATADV_TT_RESPONSE:
628                 batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_RX);
629
630                 if (batadv_is_my_mac(bat_priv, tt_query->dst)) {
631                         /* packet needs to be linearized to access the TT
632                          * changes
633                          */
634                         if (skb_linearize(skb) < 0)
635                                 goto out;
636                         /* skb_linearize() possibly changed skb->data */
637                         tt_query = (struct batadv_tt_query_packet *)skb->data;
638
639                         tt_size = batadv_tt_len(ntohs(tt_query->tt_data));
640
641                         /* Ensure we have all the claimed data */
642                         packet_size = sizeof(struct batadv_tt_query_packet);
643                         packet_size += tt_size;
644                         if (unlikely(skb_headlen(skb) < packet_size))
645                                 goto out;
646
647                         batadv_handle_tt_response(bat_priv, tt_query);
648                 } else {
649                         if (tt_query->flags & BATADV_TT_FULL_TABLE)
650                                 tt_flag =  'F';
651                         else
652                                 tt_flag = '.';
653                         batadv_dbg(BATADV_DBG_TT, bat_priv,
654                                    "Routing TT_RESPONSE to %pM [%c]\n",
655                                    tt_query->dst,
656                                    tt_flag);
657                         return batadv_route_unicast_packet(skb, recv_if);
658                 }
659                 break;
660         }
661
662 out:
663         /* returning NET_RX_DROP will make the caller function kfree the skb */
664         return NET_RX_DROP;
665 }
666
667 int batadv_recv_roam_adv(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
668 {
669         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
670         struct batadv_roam_adv_packet *roam_adv_packet;
671         struct batadv_orig_node *orig_node;
672
673         if (batadv_check_unicast_packet(bat_priv, skb,
674                                         sizeof(*roam_adv_packet)) < 0)
675                 goto out;
676
677         batadv_inc_counter(bat_priv, BATADV_CNT_TT_ROAM_ADV_RX);
678
679         roam_adv_packet = (struct batadv_roam_adv_packet *)skb->data;
680
681         if (!batadv_is_my_mac(bat_priv, roam_adv_packet->dst))
682                 return batadv_route_unicast_packet(skb, recv_if);
683
684         /* check if it is a backbone gateway. we don't accept
685          * roaming advertisement from it, as it has the same
686          * entries as we have.
687          */
688         if (batadv_bla_is_backbone_gw_orig(bat_priv, roam_adv_packet->src))
689                 goto out;
690
691         orig_node = batadv_orig_hash_find(bat_priv, roam_adv_packet->src);
692         if (!orig_node)
693                 goto out;
694
695         batadv_dbg(BATADV_DBG_TT, bat_priv,
696                    "Received ROAMING_ADV from %pM (client %pM)\n",
697                    roam_adv_packet->src, roam_adv_packet->client);
698
699         batadv_tt_global_add(bat_priv, orig_node, roam_adv_packet->client,
700                              BATADV_TT_CLIENT_ROAM,
701                              atomic_read(&orig_node->last_ttvn) + 1);
702
703         batadv_orig_node_free_ref(orig_node);
704 out:
705         /* returning NET_RX_DROP will make the caller function kfree the skb */
706         return NET_RX_DROP;
707 }
708
709 /* find a suitable router for this originator, and use
710  * bonding if possible. increases the found neighbors
711  * refcount.
712  */
713 struct batadv_neigh_node *
714 batadv_find_router(struct batadv_priv *bat_priv,
715                    struct batadv_orig_node *orig_node,
716                    const struct batadv_hard_iface *recv_if)
717 {
718         struct batadv_orig_node *primary_orig_node;
719         struct batadv_orig_node *router_orig;
720         struct batadv_neigh_node *router;
721         static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
722         int bonding_enabled;
723         uint8_t *primary_addr;
724
725         if (!orig_node)
726                 return NULL;
727
728         router = batadv_orig_node_get_router(orig_node);
729         if (!router)
730                 goto err;
731
732         /* without bonding, the first node should
733          * always choose the default router.
734          */
735         bonding_enabled = atomic_read(&bat_priv->bonding);
736
737         rcu_read_lock();
738         /* select default router to output */
739         router_orig = router->orig_node;
740         if (!router_orig)
741                 goto err_unlock;
742
743         if ((!recv_if) && (!bonding_enabled))
744                 goto return_router;
745
746         primary_addr = router_orig->primary_addr;
747
748         /* if we have something in the primary_addr, we can search
749          * for a potential bonding candidate.
750          */
751         if (batadv_compare_eth(primary_addr, zero_mac))
752                 goto return_router;
753
754         /* find the orig_node which has the primary interface. might
755          * even be the same as our router_orig in many cases
756          */
757         if (batadv_compare_eth(primary_addr, router_orig->orig)) {
758                 primary_orig_node = router_orig;
759         } else {
760                 primary_orig_node = batadv_orig_hash_find(bat_priv,
761                                                           primary_addr);
762                 if (!primary_orig_node)
763                         goto return_router;
764
765                 batadv_orig_node_free_ref(primary_orig_node);
766         }
767
768         /* with less than 2 candidates, we can't do any
769          * bonding and prefer the original router.
770          */
771         if (atomic_read(&primary_orig_node->bond_candidates) < 2)
772                 goto return_router;
773
774         /* all nodes between should choose a candidate which
775          * is is not on the interface where the packet came
776          * in.
777          */
778         batadv_neigh_node_free_ref(router);
779
780         if (bonding_enabled)
781                 router = batadv_find_bond_router(primary_orig_node, recv_if);
782         else
783                 router = batadv_find_ifalter_router(primary_orig_node, recv_if);
784
785 return_router:
786         if (router && router->if_incoming->if_status != BATADV_IF_ACTIVE)
787                 goto err_unlock;
788
789         rcu_read_unlock();
790         return router;
791 err_unlock:
792         rcu_read_unlock();
793 err:
794         if (router)
795                 batadv_neigh_node_free_ref(router);
796         return NULL;
797 }
798
799 static int batadv_route_unicast_packet(struct sk_buff *skb,
800                                        struct batadv_hard_iface *recv_if)
801 {
802         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
803         struct batadv_orig_node *orig_node = NULL;
804         struct batadv_neigh_node *neigh_node = NULL;
805         struct batadv_unicast_packet *unicast_packet;
806         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
807         int ret = NET_RX_DROP;
808         struct sk_buff *new_skb;
809
810         unicast_packet = (struct batadv_unicast_packet *)skb->data;
811
812         /* TTL exceeded */
813         if (unicast_packet->header.ttl < 2) {
814                 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
815                          ethhdr->h_source, unicast_packet->dest);
816                 goto out;
817         }
818
819         /* get routing information */
820         orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
821
822         if (!orig_node)
823                 goto out;
824
825         /* find_router() increases neigh_nodes refcount if found. */
826         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
827
828         if (!neigh_node)
829                 goto out;
830
831         /* create a copy of the skb, if needed, to modify it. */
832         if (skb_cow(skb, ETH_HLEN) < 0)
833                 goto out;
834
835         unicast_packet = (struct batadv_unicast_packet *)skb->data;
836
837         if (unicast_packet->header.packet_type == BATADV_UNICAST &&
838             atomic_read(&bat_priv->fragmentation) &&
839             skb->len > neigh_node->if_incoming->net_dev->mtu) {
840                 ret = batadv_frag_send_skb(skb, bat_priv,
841                                            neigh_node->if_incoming,
842                                            neigh_node->addr);
843                 goto out;
844         }
845
846         if (unicast_packet->header.packet_type == BATADV_UNICAST_FRAG &&
847             batadv_frag_can_reassemble(skb,
848                                        neigh_node->if_incoming->net_dev->mtu)) {
849                 ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
850
851                 if (ret == NET_RX_DROP)
852                         goto out;
853
854                 /* packet was buffered for late merge */
855                 if (!new_skb) {
856                         ret = NET_RX_SUCCESS;
857                         goto out;
858                 }
859
860                 skb = new_skb;
861                 unicast_packet = (struct batadv_unicast_packet *)skb->data;
862         }
863
864         /* decrement ttl */
865         unicast_packet->header.ttl--;
866
867         /* network code packet if possible */
868         if (batadv_nc_skb_forward(skb, neigh_node, ethhdr)) {
869                 ret = NET_RX_SUCCESS;
870         } else if (batadv_send_skb_to_orig(skb, orig_node, recv_if)) {
871                 ret = NET_RX_SUCCESS;
872
873                 /* Update stats counter */
874                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
875                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
876                                    skb->len + ETH_HLEN);
877         }
878
879 out:
880         if (neigh_node)
881                 batadv_neigh_node_free_ref(neigh_node);
882         if (orig_node)
883                 batadv_orig_node_free_ref(orig_node);
884         return ret;
885 }
886
887 /**
888  * batadv_reroute_unicast_packet - update the unicast header for re-routing
889  * @bat_priv: the bat priv with all the soft interface information
890  * @unicast_packet: the unicast header to be updated
891  * @dst_addr: the payload destination
892  *
893  * Search the translation table for dst_addr and update the unicast header with
894  * the new corresponding information (originator address where the destination
895  * client currently is and its known TTVN)
896  *
897  * Returns true if the packet header has been updated, false otherwise
898  */
899 static bool
900 batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
901                               struct batadv_unicast_packet *unicast_packet,
902                               uint8_t *dst_addr)
903 {
904         struct batadv_orig_node *orig_node = NULL;
905         struct batadv_hard_iface *primary_if = NULL;
906         bool ret = false;
907         uint8_t *orig_addr, orig_ttvn;
908
909         if (batadv_is_my_client(bat_priv, dst_addr)) {
910                 primary_if = batadv_primary_if_get_selected(bat_priv);
911                 if (!primary_if)
912                         goto out;
913                 orig_addr = primary_if->net_dev->dev_addr;
914                 orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
915         } else {
916                 orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr);
917                 if (!orig_node)
918                         goto out;
919
920                 if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
921                         goto out;
922
923                 orig_addr = orig_node->orig;
924                 orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
925         }
926
927         /* update the packet header */
928         memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
929         unicast_packet->ttvn = orig_ttvn;
930
931         ret = true;
932 out:
933         if (primary_if)
934                 batadv_hardif_free_ref(primary_if);
935         if (orig_node)
936                 batadv_orig_node_free_ref(orig_node);
937
938         return ret;
939 }
940
941 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
942                                      struct sk_buff *skb, int hdr_len) {
943         uint8_t curr_ttvn, old_ttvn;
944         struct batadv_orig_node *orig_node;
945         struct ethhdr *ethhdr;
946         struct batadv_hard_iface *primary_if;
947         struct batadv_unicast_packet *unicast_packet;
948         int is_old_ttvn;
949
950         /* check if there is enough data before accessing it */
951         if (pskb_may_pull(skb, hdr_len + ETH_HLEN) < 0)
952                 return 0;
953
954         /* create a copy of the skb (in case of for re-routing) to modify it. */
955         if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
956                 return 0;
957
958         unicast_packet = (struct batadv_unicast_packet *)skb->data;
959         ethhdr = (struct ethhdr *)(skb->data + hdr_len);
960
961         /* check if the destination client was served by this node and it is now
962          * roaming. In this case, it means that the node has got a ROAM_ADV
963          * message and that it knows the new destination in the mesh to re-route
964          * the packet to
965          */
966         if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest)) {
967                 if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
968                                                   ethhdr->h_dest))
969                         net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
970                                                  bat_priv,
971                                                  "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
972                                                  unicast_packet->dest,
973                                                  ethhdr->h_dest);
974                 /* at this point the mesh destination should have been
975                  * substituted with the originator address found in the global
976                  * table. If not, let the packet go untouched anyway because
977                  * there is nothing the node can do
978                  */
979                 return 1;
980         }
981
982         /* retrieve the TTVN known by this node for the packet destination. This
983          * value is used later to check if the node which sent (or re-routed
984          * last time) the packet had an updated information or not
985          */
986         curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
987         if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
988                 orig_node = batadv_orig_hash_find(bat_priv,
989                                                   unicast_packet->dest);
990                 /* if it is not possible to find the orig_node representing the
991                  * destination, the packet can immediately be dropped as it will
992                  * not be possible to deliver it
993                  */
994                 if (!orig_node)
995                         return 0;
996
997                 curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
998                 batadv_orig_node_free_ref(orig_node);
999         }
1000
1001         /* check if the TTVN contained in the packet is fresher than what the
1002          * node knows
1003          */
1004         is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
1005         if (!is_old_ttvn)
1006                 return 1;
1007
1008         old_ttvn = unicast_packet->ttvn;
1009         /* the packet was forged based on outdated network information. Its
1010          * destination can possibly be updated and forwarded towards the new
1011          * target host
1012          */
1013         if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
1014                                           ethhdr->h_dest)) {
1015                 net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
1016                                          "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
1017                                          unicast_packet->dest, ethhdr->h_dest,
1018                                          old_ttvn, curr_ttvn);
1019                 return 1;
1020         }
1021
1022         /* the packet has not been re-routed: either the destination is
1023          * currently served by this node or there is no destination at all and
1024          * it is possible to drop the packet
1025          */
1026         if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
1027                 return 0;
1028
1029         /* update the header in order to let the packet be delivered to this
1030          * node's soft interface
1031          */
1032         primary_if = batadv_primary_if_get_selected(bat_priv);
1033         if (!primary_if)
1034                 return 0;
1035
1036         memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
1037
1038         batadv_hardif_free_ref(primary_if);
1039
1040         unicast_packet->ttvn = curr_ttvn;
1041
1042         return 1;
1043 }
1044
1045 int batadv_recv_unicast_packet(struct sk_buff *skb,
1046                                struct batadv_hard_iface *recv_if)
1047 {
1048         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1049         struct batadv_unicast_packet *unicast_packet;
1050         struct batadv_unicast_4addr_packet *unicast_4addr_packet;
1051         uint8_t *orig_addr;
1052         struct batadv_orig_node *orig_node = NULL;
1053         int check, hdr_size = sizeof(*unicast_packet);
1054         bool is4addr;
1055
1056         unicast_packet = (struct batadv_unicast_packet *)skb->data;
1057         unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
1058
1059         is4addr = unicast_packet->header.packet_type == BATADV_UNICAST_4ADDR;
1060         /* the caller function should have already pulled 2 bytes */
1061         if (is4addr)
1062                 hdr_size = sizeof(*unicast_4addr_packet);
1063
1064         /* function returns -EREMOTE for promiscuous packets */
1065         check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
1066
1067         /* Even though the packet is not for us, we might save it to use for
1068          * decoding a later received coded packet
1069          */
1070         if (check == -EREMOTE)
1071                 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
1072
1073         if (check < 0)
1074                 return NET_RX_DROP;
1075         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
1076                 return NET_RX_DROP;
1077
1078         /* packet for me */
1079         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
1080                 if (is4addr) {
1081                         batadv_dat_inc_counter(bat_priv,
1082                                                unicast_4addr_packet->subtype);
1083                         orig_addr = unicast_4addr_packet->src;
1084                         orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
1085                 }
1086
1087                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
1088                                                           hdr_size))
1089                         goto rx_success;
1090                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
1091                                                         hdr_size))
1092                         goto rx_success;
1093
1094                 batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1095                                     orig_node);
1096
1097 rx_success:
1098                 if (orig_node)
1099                         batadv_orig_node_free_ref(orig_node);
1100
1101                 return NET_RX_SUCCESS;
1102         }
1103
1104         return batadv_route_unicast_packet(skb, recv_if);
1105 }
1106
1107 int batadv_recv_ucast_frag_packet(struct sk_buff *skb,
1108                                   struct batadv_hard_iface *recv_if)
1109 {
1110         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1111         struct batadv_unicast_frag_packet *unicast_packet;
1112         int hdr_size = sizeof(*unicast_packet);
1113         struct sk_buff *new_skb = NULL;
1114         int ret;
1115
1116         if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1117                 return NET_RX_DROP;
1118
1119         if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
1120                 return NET_RX_DROP;
1121
1122         unicast_packet = (struct batadv_unicast_frag_packet *)skb->data;
1123
1124         /* packet for me */
1125         if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
1126                 ret = batadv_frag_reassemble_skb(skb, bat_priv, &new_skb);
1127
1128                 if (ret == NET_RX_DROP)
1129                         return NET_RX_DROP;
1130
1131                 /* packet was buffered for late merge */
1132                 if (!new_skb)
1133                         return NET_RX_SUCCESS;
1134
1135                 if (batadv_dat_snoop_incoming_arp_request(bat_priv, new_skb,
1136                                                           hdr_size))
1137                         goto rx_success;
1138                 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, new_skb,
1139                                                         hdr_size))
1140                         goto rx_success;
1141
1142                 batadv_interface_rx(recv_if->soft_iface, new_skb, recv_if,
1143                                     sizeof(struct batadv_unicast_packet), NULL);
1144
1145 rx_success:
1146                 return NET_RX_SUCCESS;
1147         }
1148
1149         return batadv_route_unicast_packet(skb, recv_if);
1150 }
1151
1152
1153 int batadv_recv_bcast_packet(struct sk_buff *skb,
1154                              struct batadv_hard_iface *recv_if)
1155 {
1156         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1157         struct batadv_orig_node *orig_node = NULL;
1158         struct batadv_bcast_packet *bcast_packet;
1159         struct ethhdr *ethhdr;
1160         int hdr_size = sizeof(*bcast_packet);
1161         int ret = NET_RX_DROP;
1162         int32_t seq_diff;
1163
1164         /* drop packet if it has not necessary minimum size */
1165         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1166                 goto out;
1167
1168         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1169
1170         /* packet with broadcast indication but unicast recipient */
1171         if (!is_broadcast_ether_addr(ethhdr->h_dest))
1172                 goto out;
1173
1174         /* packet with broadcast sender address */
1175         if (is_broadcast_ether_addr(ethhdr->h_source))
1176                 goto out;
1177
1178         /* ignore broadcasts sent by myself */
1179         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1180                 goto out;
1181
1182         bcast_packet = (struct batadv_bcast_packet *)skb->data;
1183
1184         /* ignore broadcasts originated by myself */
1185         if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1186                 goto out;
1187
1188         if (bcast_packet->header.ttl < 2)
1189                 goto out;
1190
1191         orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1192
1193         if (!orig_node)
1194                 goto out;
1195
1196         spin_lock_bh(&orig_node->bcast_seqno_lock);
1197
1198         /* check whether the packet is a duplicate */
1199         if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1200                             ntohl(bcast_packet->seqno)))
1201                 goto spin_unlock;
1202
1203         seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
1204
1205         /* check whether the packet is old and the host just restarted. */
1206         if (batadv_window_protected(bat_priv, seq_diff,
1207                                     &orig_node->bcast_seqno_reset))
1208                 goto spin_unlock;
1209
1210         /* mark broadcast in flood history, update window position
1211          * if required.
1212          */
1213         if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1214                 orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);
1215
1216         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1217
1218         /* check whether this has been sent by another originator before */
1219         if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1220                 goto out;
1221
1222         /* rebroadcast packet */
1223         batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1224
1225         /* don't hand the broadcast up if it is from an originator
1226          * from the same backbone.
1227          */
1228         if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1229                 goto out;
1230
1231         if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1232                 goto rx_success;
1233         if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1234                 goto rx_success;
1235
1236         /* broadcast for me */
1237         batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1238                             orig_node);
1239
1240 rx_success:
1241         ret = NET_RX_SUCCESS;
1242         goto out;
1243
1244 spin_unlock:
1245         spin_unlock_bh(&orig_node->bcast_seqno_lock);
1246 out:
1247         if (orig_node)
1248                 batadv_orig_node_free_ref(orig_node);
1249         return ret;
1250 }
1251
1252 int batadv_recv_vis_packet(struct sk_buff *skb,
1253                            struct batadv_hard_iface *recv_if)
1254 {
1255         struct batadv_vis_packet *vis_packet;
1256         struct ethhdr *ethhdr;
1257         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1258         int hdr_size = sizeof(*vis_packet);
1259
1260         /* keep skb linear */
1261         if (skb_linearize(skb) < 0)
1262                 return NET_RX_DROP;
1263
1264         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1265                 return NET_RX_DROP;
1266
1267         vis_packet = (struct batadv_vis_packet *)skb->data;
1268         ethhdr = (struct ethhdr *)skb_mac_header(skb);
1269
1270         /* not for me */
1271         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1272                 return NET_RX_DROP;
1273
1274         /* ignore own packets */
1275         if (batadv_is_my_mac(bat_priv, vis_packet->vis_orig))
1276                 return NET_RX_DROP;
1277
1278         if (batadv_is_my_mac(bat_priv, vis_packet->sender_orig))
1279                 return NET_RX_DROP;
1280
1281         switch (vis_packet->vis_type) {
1282         case BATADV_VIS_TYPE_SERVER_SYNC:
1283                 batadv_receive_server_sync_packet(bat_priv, vis_packet,
1284                                                   skb_headlen(skb));
1285                 break;
1286
1287         case BATADV_VIS_TYPE_CLIENT_UPDATE:
1288                 batadv_receive_client_update_packet(bat_priv, vis_packet,
1289                                                     skb_headlen(skb));
1290                 break;
1291
1292         default:        /* ignore unknown packet */
1293                 break;
1294         }
1295
1296         /* We take a copy of the data in the packet, so we should
1297          * always free the skbuf.
1298          */
1299         return NET_RX_DROP;
1300 }