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[~andy/linux] / net / batman-adv / send.c
1 /* Copyright (C) 2007-2014 B.A.T.M.A.N. contributors:
2  *
3  * Marek Lindner, Simon Wunderlich
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of version 2 of the GNU General Public
7  * License as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17
18 #include "main.h"
19 #include "distributed-arp-table.h"
20 #include "send.h"
21 #include "routing.h"
22 #include "translation-table.h"
23 #include "soft-interface.h"
24 #include "hard-interface.h"
25 #include "gateway_common.h"
26 #include "gateway_client.h"
27 #include "originator.h"
28 #include "network-coding.h"
29 #include "fragmentation.h"
30
31 static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
32
33 /* send out an already prepared packet to the given address via the
34  * specified batman interface
35  */
36 int batadv_send_skb_packet(struct sk_buff *skb,
37                            struct batadv_hard_iface *hard_iface,
38                            const uint8_t *dst_addr)
39 {
40         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
41         struct ethhdr *ethhdr;
42
43         if (hard_iface->if_status != BATADV_IF_ACTIVE)
44                 goto send_skb_err;
45
46         if (unlikely(!hard_iface->net_dev))
47                 goto send_skb_err;
48
49         if (!(hard_iface->net_dev->flags & IFF_UP)) {
50                 pr_warn("Interface %s is not up - can't send packet via that interface!\n",
51                         hard_iface->net_dev->name);
52                 goto send_skb_err;
53         }
54
55         /* push to the ethernet header. */
56         if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
57                 goto send_skb_err;
58
59         skb_reset_mac_header(skb);
60
61         ethhdr = eth_hdr(skb);
62         memcpy(ethhdr->h_source, hard_iface->net_dev->dev_addr, ETH_ALEN);
63         memcpy(ethhdr->h_dest, dst_addr, ETH_ALEN);
64         ethhdr->h_proto = htons(ETH_P_BATMAN);
65
66         skb_set_network_header(skb, ETH_HLEN);
67         skb->protocol = htons(ETH_P_BATMAN);
68
69         skb->dev = hard_iface->net_dev;
70
71         /* Save a clone of the skb to use when decoding coded packets */
72         batadv_nc_skb_store_for_decoding(bat_priv, skb);
73
74         /* dev_queue_xmit() returns a negative result on error.  However on
75          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
76          * (which is > 0). This will not be treated as an error.
77          */
78         return dev_queue_xmit(skb);
79 send_skb_err:
80         kfree_skb(skb);
81         return NET_XMIT_DROP;
82 }
83
84 /**
85  * batadv_send_skb_to_orig - Lookup next-hop and transmit skb.
86  * @skb: Packet to be transmitted.
87  * @orig_node: Final destination of the packet.
88  * @recv_if: Interface used when receiving the packet (can be NULL).
89  *
90  * Looks up the best next-hop towards the passed originator and passes the
91  * skb on for preparation of MAC header. If the packet originated from this
92  * host, NULL can be passed as recv_if and no interface alternating is
93  * attempted.
94  *
95  * Returns NET_XMIT_SUCCESS on success, NET_XMIT_DROP on failure, or
96  * NET_XMIT_POLICED if the skb is buffered for later transmit.
97  */
98 int batadv_send_skb_to_orig(struct sk_buff *skb,
99                             struct batadv_orig_node *orig_node,
100                             struct batadv_hard_iface *recv_if)
101 {
102         struct batadv_priv *bat_priv = orig_node->bat_priv;
103         struct batadv_neigh_node *neigh_node;
104         int ret = NET_XMIT_DROP;
105
106         /* batadv_find_router() increases neigh_nodes refcount if found. */
107         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
108         if (!neigh_node)
109                 goto out;
110
111         /* Check if the skb is too large to send in one piece and fragment
112          * it if needed.
113          */
114         if (atomic_read(&bat_priv->fragmentation) &&
115             skb->len > neigh_node->if_incoming->net_dev->mtu) {
116                 /* Fragment and send packet. */
117                 if (batadv_frag_send_packet(skb, orig_node, neigh_node))
118                         ret = NET_XMIT_SUCCESS;
119
120                 goto out;
121         }
122
123         /* try to network code the packet, if it is received on an interface
124          * (i.e. being forwarded). If the packet originates from this node or if
125          * network coding fails, then send the packet as usual.
126          */
127         if (recv_if && batadv_nc_skb_forward(skb, neigh_node)) {
128                 ret = NET_XMIT_POLICED;
129         } else {
130                 batadv_send_skb_packet(skb, neigh_node->if_incoming,
131                                        neigh_node->addr);
132                 ret = NET_XMIT_SUCCESS;
133         }
134
135 out:
136         if (neigh_node)
137                 batadv_neigh_node_free_ref(neigh_node);
138
139         return ret;
140 }
141
142 /**
143  * batadv_send_skb_push_fill_unicast - extend the buffer and initialize the
144  *  common fields for unicast packets
145  * @skb: the skb carrying the unicast header to initialize
146  * @hdr_size: amount of bytes to push at the beginning of the skb
147  * @orig_node: the destination node
148  *
149  * Returns false if the buffer extension was not possible or true otherwise.
150  */
151 static bool
152 batadv_send_skb_push_fill_unicast(struct sk_buff *skb, int hdr_size,
153                                   struct batadv_orig_node *orig_node)
154 {
155         struct batadv_unicast_packet *unicast_packet;
156         uint8_t ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
157
158         if (batadv_skb_head_push(skb, hdr_size) < 0)
159                 return false;
160
161         unicast_packet = (struct batadv_unicast_packet *)skb->data;
162         unicast_packet->version = BATADV_COMPAT_VERSION;
163         /* batman packet type: unicast */
164         unicast_packet->packet_type = BATADV_UNICAST;
165         /* set unicast ttl */
166         unicast_packet->ttl = BATADV_TTL;
167         /* copy the destination for faster routing */
168         memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
169         /* set the destination tt version number */
170         unicast_packet->ttvn = ttvn;
171
172         return true;
173 }
174
175 /**
176  * batadv_send_skb_prepare_unicast - encapsulate an skb with a unicast header
177  * @skb: the skb containing the payload to encapsulate
178  * @orig_node: the destination node
179  *
180  * Returns false if the payload could not be encapsulated or true otherwise.
181  */
182 static bool batadv_send_skb_prepare_unicast(struct sk_buff *skb,
183                                             struct batadv_orig_node *orig_node)
184 {
185         size_t uni_size = sizeof(struct batadv_unicast_packet);
186
187         return batadv_send_skb_push_fill_unicast(skb, uni_size, orig_node);
188 }
189
190 /**
191  * batadv_send_skb_prepare_unicast_4addr - encapsulate an skb with a
192  *  unicast 4addr header
193  * @bat_priv: the bat priv with all the soft interface information
194  * @skb: the skb containing the payload to encapsulate
195  * @orig_node: the destination node
196  * @packet_subtype: the unicast 4addr packet subtype to use
197  *
198  * Returns false if the payload could not be encapsulated or true otherwise.
199  */
200 bool batadv_send_skb_prepare_unicast_4addr(struct batadv_priv *bat_priv,
201                                            struct sk_buff *skb,
202                                            struct batadv_orig_node *orig,
203                                            int packet_subtype)
204 {
205         struct batadv_hard_iface *primary_if;
206         struct batadv_unicast_4addr_packet *uc_4addr_packet;
207         bool ret = false;
208
209         primary_if = batadv_primary_if_get_selected(bat_priv);
210         if (!primary_if)
211                 goto out;
212
213         /* Pull the header space and fill the unicast_packet substructure.
214          * We can do that because the first member of the uc_4addr_packet
215          * is of type struct unicast_packet
216          */
217         if (!batadv_send_skb_push_fill_unicast(skb, sizeof(*uc_4addr_packet),
218                                                orig))
219                 goto out;
220
221         uc_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
222         uc_4addr_packet->u.packet_type = BATADV_UNICAST_4ADDR;
223         memcpy(uc_4addr_packet->src, primary_if->net_dev->dev_addr, ETH_ALEN);
224         uc_4addr_packet->subtype = packet_subtype;
225         uc_4addr_packet->reserved = 0;
226
227         ret = true;
228 out:
229         if (primary_if)
230                 batadv_hardif_free_ref(primary_if);
231         return ret;
232 }
233
234 /**
235  * batadv_send_skb_unicast - encapsulate and send an skb via unicast
236  * @bat_priv: the bat priv with all the soft interface information
237  * @skb: payload to send
238  * @packet_type: the batman unicast packet type to use
239  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
240  *  4addr packets)
241  * @orig_node: the originator to send the packet to
242  * @vid: the vid to be used to search the translation table
243  *
244  * Wrap the given skb into a batman-adv unicast or unicast-4addr header
245  * depending on whether BATADV_UNICAST or BATADV_UNICAST_4ADDR was supplied
246  * as packet_type. Then send this frame to the given orig_node and release a
247  * reference to this orig_node.
248  *
249  * Returns NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
250  */
251 static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
252                                    struct sk_buff *skb, int packet_type,
253                                    int packet_subtype,
254                                    struct batadv_orig_node *orig_node,
255                                    unsigned short vid)
256 {
257         struct ethhdr *ethhdr;
258         struct batadv_unicast_packet *unicast_packet;
259         int ret = NET_XMIT_DROP, hdr_size;
260
261         if (!orig_node)
262                 goto out;
263
264         switch (packet_type) {
265         case BATADV_UNICAST:
266                 if (!batadv_send_skb_prepare_unicast(skb, orig_node))
267                         goto out;
268
269                 hdr_size = sizeof(*unicast_packet);
270                 break;
271         case BATADV_UNICAST_4ADDR:
272                 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
273                                                            orig_node,
274                                                            packet_subtype))
275                         goto out;
276
277                 hdr_size = sizeof(struct batadv_unicast_4addr_packet);
278                 break;
279         default:
280                 /* this function supports UNICAST and UNICAST_4ADDR only. It
281                  * should never be invoked with any other packet type
282                  */
283                 goto out;
284         }
285
286         ethhdr = (struct ethhdr *)(skb->data + hdr_size);
287         unicast_packet = (struct batadv_unicast_packet *)skb->data;
288
289         /* inform the destination node that we are still missing a correct route
290          * for this client. The destination will receive this packet and will
291          * try to reroute it because the ttvn contained in the header is less
292          * than the current one
293          */
294         if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest, vid))
295                 unicast_packet->ttvn = unicast_packet->ttvn - 1;
296
297         if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
298                 ret = NET_XMIT_SUCCESS;
299
300 out:
301         if (orig_node)
302                 batadv_orig_node_free_ref(orig_node);
303         if (ret == NET_XMIT_DROP)
304                 kfree_skb(skb);
305         return ret;
306 }
307
308 /**
309  * batadv_send_skb_via_tt_generic - send an skb via TT lookup
310  * @bat_priv: the bat priv with all the soft interface information
311  * @skb: payload to send
312  * @packet_type: the batman unicast packet type to use
313  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
314  *  4addr packets)
315  * @vid: the vid to be used to search the translation table
316  *
317  * Look up the recipient node for the destination address in the ethernet
318  * header via the translation table. Wrap the given skb into a batman-adv
319  * unicast or unicast-4addr header depending on whether BATADV_UNICAST or
320  * BATADV_UNICAST_4ADDR was supplied as packet_type. Then send this frame
321  * to the according destination node.
322  *
323  * Returns NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
324  */
325 int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
326                                    struct sk_buff *skb, int packet_type,
327                                    int packet_subtype, uint8_t *dst_hint,
328                                    unsigned short vid)
329 {
330         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
331         struct batadv_orig_node *orig_node;
332         uint8_t *src, *dst;
333
334         src = ethhdr->h_source;
335         dst = ethhdr->h_dest;
336
337         /* if we got an hint! let's send the packet to this client (if any) */
338         if (dst_hint) {
339                 src = NULL;
340                 dst = dst_hint;
341         }
342         orig_node = batadv_transtable_search(bat_priv, src, dst, vid);
343
344         return batadv_send_skb_unicast(bat_priv, skb, packet_type,
345                                        packet_subtype, orig_node, vid);
346 }
347
348 /**
349  * batadv_send_skb_via_gw - send an skb via gateway lookup
350  * @bat_priv: the bat priv with all the soft interface information
351  * @skb: payload to send
352  * @vid: the vid to be used to search the translation table
353  *
354  * Look up the currently selected gateway. Wrap the given skb into a batman-adv
355  * unicast header and send this frame to this gateway node.
356  *
357  * Returns NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
358  */
359 int batadv_send_skb_via_gw(struct batadv_priv *bat_priv, struct sk_buff *skb,
360                            unsigned short vid)
361 {
362         struct batadv_orig_node *orig_node;
363
364         orig_node = batadv_gw_get_selected_orig(bat_priv);
365         return batadv_send_skb_unicast(bat_priv, skb, BATADV_UNICAST, 0,
366                                        orig_node, vid);
367 }
368
369 void batadv_schedule_bat_ogm(struct batadv_hard_iface *hard_iface)
370 {
371         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
372
373         if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
374             (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
375                 return;
376
377         /* the interface gets activated here to avoid race conditions between
378          * the moment of activating the interface in
379          * hardif_activate_interface() where the originator mac is set and
380          * outdated packets (especially uninitialized mac addresses) in the
381          * packet queue
382          */
383         if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
384                 hard_iface->if_status = BATADV_IF_ACTIVE;
385
386         bat_priv->bat_algo_ops->bat_ogm_schedule(hard_iface);
387 }
388
389 static void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet)
390 {
391         if (forw_packet->skb)
392                 kfree_skb(forw_packet->skb);
393         if (forw_packet->if_incoming)
394                 batadv_hardif_free_ref(forw_packet->if_incoming);
395         if (forw_packet->if_outgoing)
396                 batadv_hardif_free_ref(forw_packet->if_outgoing);
397         kfree(forw_packet);
398 }
399
400 static void
401 _batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
402                                  struct batadv_forw_packet *forw_packet,
403                                  unsigned long send_time)
404 {
405         /* add new packet to packet list */
406         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
407         hlist_add_head(&forw_packet->list, &bat_priv->forw_bcast_list);
408         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
409
410         /* start timer for this packet */
411         queue_delayed_work(batadv_event_workqueue, &forw_packet->delayed_work,
412                            send_time);
413 }
414
415 /* add a broadcast packet to the queue and setup timers. broadcast packets
416  * are sent multiple times to increase probability for being received.
417  *
418  * This function returns NETDEV_TX_OK on success and NETDEV_TX_BUSY on
419  * errors.
420  *
421  * The skb is not consumed, so the caller should make sure that the
422  * skb is freed.
423  */
424 int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
425                                     const struct sk_buff *skb,
426                                     unsigned long delay)
427 {
428         struct batadv_hard_iface *primary_if = NULL;
429         struct batadv_forw_packet *forw_packet;
430         struct batadv_bcast_packet *bcast_packet;
431         struct sk_buff *newskb;
432
433         if (!batadv_atomic_dec_not_zero(&bat_priv->bcast_queue_left)) {
434                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
435                            "bcast packet queue full\n");
436                 goto out;
437         }
438
439         primary_if = batadv_primary_if_get_selected(bat_priv);
440         if (!primary_if)
441                 goto out_and_inc;
442
443         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
444
445         if (!forw_packet)
446                 goto out_and_inc;
447
448         newskb = skb_copy(skb, GFP_ATOMIC);
449         if (!newskb)
450                 goto packet_free;
451
452         /* as we have a copy now, it is safe to decrease the TTL */
453         bcast_packet = (struct batadv_bcast_packet *)newskb->data;
454         bcast_packet->ttl--;
455
456         skb_reset_mac_header(newskb);
457
458         forw_packet->skb = newskb;
459         forw_packet->if_incoming = primary_if;
460         forw_packet->if_outgoing = NULL;
461
462         /* how often did we send the bcast packet ? */
463         forw_packet->num_packets = 0;
464
465         INIT_DELAYED_WORK(&forw_packet->delayed_work,
466                           batadv_send_outstanding_bcast_packet);
467
468         _batadv_add_bcast_packet_to_list(bat_priv, forw_packet, delay);
469         return NETDEV_TX_OK;
470
471 packet_free:
472         kfree(forw_packet);
473 out_and_inc:
474         atomic_inc(&bat_priv->bcast_queue_left);
475 out:
476         if (primary_if)
477                 batadv_hardif_free_ref(primary_if);
478         return NETDEV_TX_BUSY;
479 }
480
481 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
482 {
483         struct batadv_hard_iface *hard_iface;
484         struct delayed_work *delayed_work;
485         struct batadv_forw_packet *forw_packet;
486         struct sk_buff *skb1;
487         struct net_device *soft_iface;
488         struct batadv_priv *bat_priv;
489
490         delayed_work = container_of(work, struct delayed_work, work);
491         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
492                                    delayed_work);
493         soft_iface = forw_packet->if_incoming->soft_iface;
494         bat_priv = netdev_priv(soft_iface);
495
496         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
497         hlist_del(&forw_packet->list);
498         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
499
500         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
501                 goto out;
502
503         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet))
504                 goto out;
505
506         /* rebroadcast packet */
507         rcu_read_lock();
508         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
509                 if (hard_iface->soft_iface != soft_iface)
510                         continue;
511
512                 if (forw_packet->num_packets >= hard_iface->num_bcasts)
513                         continue;
514
515                 /* send a copy of the saved skb */
516                 skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
517                 if (skb1)
518                         batadv_send_skb_packet(skb1, hard_iface,
519                                                batadv_broadcast_addr);
520         }
521         rcu_read_unlock();
522
523         forw_packet->num_packets++;
524
525         /* if we still have some more bcasts to send */
526         if (forw_packet->num_packets < BATADV_NUM_BCASTS_MAX) {
527                 _batadv_add_bcast_packet_to_list(bat_priv, forw_packet,
528                                                  msecs_to_jiffies(5));
529                 return;
530         }
531
532 out:
533         batadv_forw_packet_free(forw_packet);
534         atomic_inc(&bat_priv->bcast_queue_left);
535 }
536
537 void batadv_send_outstanding_bat_ogm_packet(struct work_struct *work)
538 {
539         struct delayed_work *delayed_work;
540         struct batadv_forw_packet *forw_packet;
541         struct batadv_priv *bat_priv;
542
543         delayed_work = container_of(work, struct delayed_work, work);
544         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
545                                    delayed_work);
546         bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
547         spin_lock_bh(&bat_priv->forw_bat_list_lock);
548         hlist_del(&forw_packet->list);
549         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
550
551         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
552                 goto out;
553
554         bat_priv->bat_algo_ops->bat_ogm_emit(forw_packet);
555
556         /* we have to have at least one packet in the queue to determine the
557          * queues wake up time unless we are shutting down.
558          *
559          * only re-schedule if this is the "original" copy, e.g. the OGM of the
560          * primary interface should only be rescheduled once per period, but
561          * this function will be called for the forw_packet instances of the
562          * other secondary interfaces as well.
563          */
564         if (forw_packet->own &&
565             forw_packet->if_incoming == forw_packet->if_outgoing)
566                 batadv_schedule_bat_ogm(forw_packet->if_incoming);
567
568 out:
569         /* don't count own packet */
570         if (!forw_packet->own)
571                 atomic_inc(&bat_priv->batman_queue_left);
572
573         batadv_forw_packet_free(forw_packet);
574 }
575
576 void
577 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
578                                  const struct batadv_hard_iface *hard_iface)
579 {
580         struct batadv_forw_packet *forw_packet;
581         struct hlist_node *safe_tmp_node;
582         bool pending;
583
584         if (hard_iface)
585                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
586                            "purge_outstanding_packets(): %s\n",
587                            hard_iface->net_dev->name);
588         else
589                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
590                            "purge_outstanding_packets()\n");
591
592         /* free bcast list */
593         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
594         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
595                                   &bat_priv->forw_bcast_list, list) {
596                 /* if purge_outstanding_packets() was called with an argument
597                  * we delete only packets belonging to the given interface
598                  */
599                 if ((hard_iface) &&
600                     (forw_packet->if_incoming != hard_iface))
601                         continue;
602
603                 spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
604
605                 /* batadv_send_outstanding_bcast_packet() will lock the list to
606                  * delete the item from the list
607                  */
608                 pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
609                 spin_lock_bh(&bat_priv->forw_bcast_list_lock);
610
611                 if (pending) {
612                         hlist_del(&forw_packet->list);
613                         batadv_forw_packet_free(forw_packet);
614                 }
615         }
616         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
617
618         /* free batman packet list */
619         spin_lock_bh(&bat_priv->forw_bat_list_lock);
620         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
621                                   &bat_priv->forw_bat_list, list) {
622                 /* if purge_outstanding_packets() was called with an argument
623                  * we delete only packets belonging to the given interface
624                  */
625                 if ((hard_iface) &&
626                     (forw_packet->if_incoming != hard_iface) &&
627                     (forw_packet->if_outgoing != hard_iface))
628                         continue;
629
630                 spin_unlock_bh(&bat_priv->forw_bat_list_lock);
631
632                 /* send_outstanding_bat_packet() will lock the list to
633                  * delete the item from the list
634                  */
635                 pending = cancel_delayed_work_sync(&forw_packet->delayed_work);
636                 spin_lock_bh(&bat_priv->forw_bat_list_lock);
637
638                 if (pending) {
639                         hlist_del(&forw_packet->list);
640                         batadv_forw_packet_free(forw_packet);
641                 }
642         }
643         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
644 }