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Linux/net/batman-adv/send.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /* Copyright (C) 2007-2018  B.A.T.M.A.N. contributors:
  3  *
  4  * Marek Lindner, Simon Wunderlich
  5  *
  6  * This program is free software; you can redistribute it and/or
  7  * modify it under the terms of version 2 of the GNU General Public
  8  * License as published by the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful, but
 11  * WITHOUT ANY WARRANTY; without even the implied warranty of
 12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 13  * General Public License for more details.
 14  *
 15  * You should have received a copy of the GNU General Public License
 16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
 17  */
 18 
 19 #include "send.h"
 20 #include "main.h"
 21 
 22 #include <linux/atomic.h>
 23 #include <linux/bug.h>
 24 #include <linux/byteorder/generic.h>
 25 #include <linux/errno.h>
 26 #include <linux/etherdevice.h>
 27 #include <linux/gfp.h>
 28 #include <linux/if.h>
 29 #include <linux/if_ether.h>
 30 #include <linux/jiffies.h>
 31 #include <linux/kernel.h>
 32 #include <linux/kref.h>
 33 #include <linux/list.h>
 34 #include <linux/netdevice.h>
 35 #include <linux/printk.h>
 36 #include <linux/rculist.h>
 37 #include <linux/rcupdate.h>
 38 #include <linux/skbuff.h>
 39 #include <linux/slab.h>
 40 #include <linux/spinlock.h>
 41 #include <linux/stddef.h>
 42 #include <linux/workqueue.h>
 43 
 44 #include "distributed-arp-table.h"
 45 #include "fragmentation.h"
 46 #include "gateway_client.h"
 47 #include "hard-interface.h"
 48 #include "log.h"
 49 #include "network-coding.h"
 50 #include "originator.h"
 51 #include "routing.h"
 52 #include "soft-interface.h"
 53 #include "translation-table.h"
 54 
 55 static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
 56 
 57 /**
 58  * batadv_send_skb_packet() - send an already prepared packet
 59  * @skb: the packet to send
 60  * @hard_iface: the interface to use to send the broadcast packet
 61  * @dst_addr: the payload destination
 62  *
 63  * Send out an already prepared packet to the given neighbor or broadcast it
 64  * using the specified interface. Either hard_iface or neigh_node must be not
 65  * NULL.
 66  * If neigh_node is NULL, then the packet is broadcasted using hard_iface,
 67  * otherwise it is sent as unicast to the given neighbor.
 68  *
 69  * Regardless of the return value, the skb is consumed.
 70  *
 71  * Return: A negative errno code is returned on a failure. A success does not
 72  * guarantee the frame will be transmitted as it may be dropped due
 73  * to congestion or traffic shaping.
 74  */
 75 int batadv_send_skb_packet(struct sk_buff *skb,
 76                            struct batadv_hard_iface *hard_iface,
 77                            const u8 *dst_addr)
 78 {
 79         struct batadv_priv *bat_priv;
 80         struct ethhdr *ethhdr;
 81         int ret;
 82 
 83         bat_priv = netdev_priv(hard_iface->soft_iface);
 84 
 85         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 86                 goto send_skb_err;
 87 
 88         if (unlikely(!hard_iface->net_dev))
 89                 goto send_skb_err;
 90 
 91         if (!(hard_iface->net_dev->flags & IFF_UP)) {
 92                 pr_warn("Interface %s is not up - can't send packet via that interface!\n",
 93                         hard_iface->net_dev->name);
 94                 goto send_skb_err;
 95         }
 96 
 97         /* push to the ethernet header. */
 98         if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
 99                 goto send_skb_err;
100 
101         skb_reset_mac_header(skb);
102 
103         ethhdr = eth_hdr(skb);
104         ether_addr_copy(ethhdr->h_source, hard_iface->net_dev->dev_addr);
105         ether_addr_copy(ethhdr->h_dest, dst_addr);
106         ethhdr->h_proto = htons(ETH_P_BATMAN);
107 
108         skb_set_network_header(skb, ETH_HLEN);
109         skb->protocol = htons(ETH_P_BATMAN);
110 
111         skb->dev = hard_iface->net_dev;
112 
113         /* Save a clone of the skb to use when decoding coded packets */
114         batadv_nc_skb_store_for_decoding(bat_priv, skb);
115 
116         /* dev_queue_xmit() returns a negative result on error.  However on
117          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
118          * (which is > 0). This will not be treated as an error.
119          */
120         ret = dev_queue_xmit(skb);
121         return net_xmit_eval(ret);
122 send_skb_err:
123         kfree_skb(skb);
124         return NET_XMIT_DROP;
125 }
126 
127 /**
128  * batadv_send_broadcast_skb() - Send broadcast packet via hard interface
129  * @skb: packet to be transmitted (with batadv header and no outer eth header)
130  * @hard_iface: outgoing interface
131  *
132  * Return: A negative errno code is returned on a failure. A success does not
133  * guarantee the frame will be transmitted as it may be dropped due
134  * to congestion or traffic shaping.
135  */
136 int batadv_send_broadcast_skb(struct sk_buff *skb,
137                               struct batadv_hard_iface *hard_iface)
138 {
139         return batadv_send_skb_packet(skb, hard_iface, batadv_broadcast_addr);
140 }
141 
142 /**
143  * batadv_send_unicast_skb() - Send unicast packet to neighbor
144  * @skb: packet to be transmitted (with batadv header and no outer eth header)
145  * @neigh: neighbor which is used as next hop to destination
146  *
147  * Return: A negative errno code is returned on a failure. A success does not
148  * guarantee the frame will be transmitted as it may be dropped due
149  * to congestion or traffic shaping.
150  */
151 int batadv_send_unicast_skb(struct sk_buff *skb,
152                             struct batadv_neigh_node *neigh)
153 {
154 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
155         struct batadv_hardif_neigh_node *hardif_neigh;
156 #endif
157         int ret;
158 
159         ret = batadv_send_skb_packet(skb, neigh->if_incoming, neigh->addr);
160 
161 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
162         hardif_neigh = batadv_hardif_neigh_get(neigh->if_incoming, neigh->addr);
163 
164         if (hardif_neigh && ret != NET_XMIT_DROP)
165                 hardif_neigh->bat_v.last_unicast_tx = jiffies;
166 
167         if (hardif_neigh)
168                 batadv_hardif_neigh_put(hardif_neigh);
169 #endif
170 
171         return ret;
172 }
173 
174 /**
175  * batadv_send_skb_to_orig() - Lookup next-hop and transmit skb.
176  * @skb: Packet to be transmitted.
177  * @orig_node: Final destination of the packet.
178  * @recv_if: Interface used when receiving the packet (can be NULL).
179  *
180  * Looks up the best next-hop towards the passed originator and passes the
181  * skb on for preparation of MAC header. If the packet originated from this
182  * host, NULL can be passed as recv_if and no interface alternating is
183  * attempted.
184  *
185  * Return: negative errno code on a failure, -EINPROGRESS if the skb is
186  * buffered for later transmit or the NET_XMIT status returned by the
187  * lower routine if the packet has been passed down.
188  */
189 int batadv_send_skb_to_orig(struct sk_buff *skb,
190                             struct batadv_orig_node *orig_node,
191                             struct batadv_hard_iface *recv_if)
192 {
193         struct batadv_priv *bat_priv = orig_node->bat_priv;
194         struct batadv_neigh_node *neigh_node;
195         int ret;
196 
197         /* batadv_find_router() increases neigh_nodes refcount if found. */
198         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
199         if (!neigh_node) {
200                 ret = -EINVAL;
201                 goto free_skb;
202         }
203 
204         /* Check if the skb is too large to send in one piece and fragment
205          * it if needed.
206          */
207         if (atomic_read(&bat_priv->fragmentation) &&
208             skb->len > neigh_node->if_incoming->net_dev->mtu) {
209                 /* Fragment and send packet. */
210                 ret = batadv_frag_send_packet(skb, orig_node, neigh_node);
211                 /* skb was consumed */
212                 skb = NULL;
213 
214                 goto put_neigh_node;
215         }
216 
217         /* try to network code the packet, if it is received on an interface
218          * (i.e. being forwarded). If the packet originates from this node or if
219          * network coding fails, then send the packet as usual.
220          */
221         if (recv_if && batadv_nc_skb_forward(skb, neigh_node))
222                 ret = -EINPROGRESS;
223         else
224                 ret = batadv_send_unicast_skb(skb, neigh_node);
225 
226         /* skb was consumed */
227         skb = NULL;
228 
229 put_neigh_node:
230         batadv_neigh_node_put(neigh_node);
231 free_skb:
232         kfree_skb(skb);
233 
234         return ret;
235 }
236 
237 /**
238  * batadv_send_skb_push_fill_unicast() - extend the buffer and initialize the
239  *  common fields for unicast packets
240  * @skb: the skb carrying the unicast header to initialize
241  * @hdr_size: amount of bytes to push at the beginning of the skb
242  * @orig_node: the destination node
243  *
244  * Return: false if the buffer extension was not possible or true otherwise.
245  */
246 static bool
247 batadv_send_skb_push_fill_unicast(struct sk_buff *skb, int hdr_size,
248                                   struct batadv_orig_node *orig_node)
249 {
250         struct batadv_unicast_packet *unicast_packet;
251         u8 ttvn = (u8)atomic_read(&orig_node->last_ttvn);
252 
253         if (batadv_skb_head_push(skb, hdr_size) < 0)
254                 return false;
255 
256         unicast_packet = (struct batadv_unicast_packet *)skb->data;
257         unicast_packet->version = BATADV_COMPAT_VERSION;
258         /* batman packet type: unicast */
259         unicast_packet->packet_type = BATADV_UNICAST;
260         /* set unicast ttl */
261         unicast_packet->ttl = BATADV_TTL;
262         /* copy the destination for faster routing */
263         ether_addr_copy(unicast_packet->dest, orig_node->orig);
264         /* set the destination tt version number */
265         unicast_packet->ttvn = ttvn;
266 
267         return true;
268 }
269 
270 /**
271  * batadv_send_skb_prepare_unicast() - encapsulate an skb with a unicast header
272  * @skb: the skb containing the payload to encapsulate
273  * @orig_node: the destination node
274  *
275  * Return: false if the payload could not be encapsulated or true otherwise.
276  */
277 static bool batadv_send_skb_prepare_unicast(struct sk_buff *skb,
278                                             struct batadv_orig_node *orig_node)
279 {
280         size_t uni_size = sizeof(struct batadv_unicast_packet);
281 
282         return batadv_send_skb_push_fill_unicast(skb, uni_size, orig_node);
283 }
284 
285 /**
286  * batadv_send_skb_prepare_unicast_4addr() - encapsulate an skb with a
287  *  unicast 4addr header
288  * @bat_priv: the bat priv with all the soft interface information
289  * @skb: the skb containing the payload to encapsulate
290  * @orig: the destination node
291  * @packet_subtype: the unicast 4addr packet subtype to use
292  *
293  * Return: false if the payload could not be encapsulated or true otherwise.
294  */
295 bool batadv_send_skb_prepare_unicast_4addr(struct batadv_priv *bat_priv,
296                                            struct sk_buff *skb,
297                                            struct batadv_orig_node *orig,
298                                            int packet_subtype)
299 {
300         struct batadv_hard_iface *primary_if;
301         struct batadv_unicast_4addr_packet *uc_4addr_packet;
302         bool ret = false;
303 
304         primary_if = batadv_primary_if_get_selected(bat_priv);
305         if (!primary_if)
306                 goto out;
307 
308         /* Pull the header space and fill the unicast_packet substructure.
309          * We can do that because the first member of the uc_4addr_packet
310          * is of type struct unicast_packet
311          */
312         if (!batadv_send_skb_push_fill_unicast(skb, sizeof(*uc_4addr_packet),
313                                                orig))
314                 goto out;
315 
316         uc_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
317         uc_4addr_packet->u.packet_type = BATADV_UNICAST_4ADDR;
318         ether_addr_copy(uc_4addr_packet->src, primary_if->net_dev->dev_addr);
319         uc_4addr_packet->subtype = packet_subtype;
320         uc_4addr_packet->reserved = 0;
321 
322         ret = true;
323 out:
324         if (primary_if)
325                 batadv_hardif_put(primary_if);
326         return ret;
327 }
328 
329 /**
330  * batadv_send_skb_unicast() - encapsulate and send an skb via unicast
331  * @bat_priv: the bat priv with all the soft interface information
332  * @skb: payload to send
333  * @packet_type: the batman unicast packet type to use
334  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
335  *  4addr packets)
336  * @orig_node: the originator to send the packet to
337  * @vid: the vid to be used to search the translation table
338  *
339  * Wrap the given skb into a batman-adv unicast or unicast-4addr header
340  * depending on whether BATADV_UNICAST or BATADV_UNICAST_4ADDR was supplied
341  * as packet_type. Then send this frame to the given orig_node.
342  *
343  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
344  */
345 int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
346                             struct sk_buff *skb, int packet_type,
347                             int packet_subtype,
348                             struct batadv_orig_node *orig_node,
349                             unsigned short vid)
350 {
351         struct batadv_unicast_packet *unicast_packet;
352         struct ethhdr *ethhdr;
353         int ret = NET_XMIT_DROP;
354 
355         if (!orig_node)
356                 goto out;
357 
358         switch (packet_type) {
359         case BATADV_UNICAST:
360                 if (!batadv_send_skb_prepare_unicast(skb, orig_node))
361                         goto out;
362                 break;
363         case BATADV_UNICAST_4ADDR:
364                 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
365                                                            orig_node,
366                                                            packet_subtype))
367                         goto out;
368                 break;
369         default:
370                 /* this function supports UNICAST and UNICAST_4ADDR only. It
371                  * should never be invoked with any other packet type
372                  */
373                 goto out;
374         }
375 
376         /* skb->data might have been reallocated by
377          * batadv_send_skb_prepare_unicast{,_4addr}()
378          */
379         ethhdr = eth_hdr(skb);
380         unicast_packet = (struct batadv_unicast_packet *)skb->data;
381 
382         /* inform the destination node that we are still missing a correct route
383          * for this client. The destination will receive this packet and will
384          * try to reroute it because the ttvn contained in the header is less
385          * than the current one
386          */
387         if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest, vid))
388                 unicast_packet->ttvn = unicast_packet->ttvn - 1;
389 
390         ret = batadv_send_skb_to_orig(skb, orig_node, NULL);
391          /* skb was consumed */
392         skb = NULL;
393 
394 out:
395         kfree_skb(skb);
396         return ret;
397 }
398 
399 /**
400  * batadv_send_skb_via_tt_generic() - send an skb via TT lookup
401  * @bat_priv: the bat priv with all the soft interface information
402  * @skb: payload to send
403  * @packet_type: the batman unicast packet type to use
404  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
405  *  4addr packets)
406  * @dst_hint: can be used to override the destination contained in the skb
407  * @vid: the vid to be used to search the translation table
408  *
409  * Look up the recipient node for the destination address in the ethernet
410  * header via the translation table. Wrap the given skb into a batman-adv
411  * unicast or unicast-4addr header depending on whether BATADV_UNICAST or
412  * BATADV_UNICAST_4ADDR was supplied as packet_type. Then send this frame
413  * to the according destination node.
414  *
415  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
416  */
417 int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
418                                    struct sk_buff *skb, int packet_type,
419                                    int packet_subtype, u8 *dst_hint,
420                                    unsigned short vid)
421 {
422         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
423         struct batadv_orig_node *orig_node;
424         u8 *src, *dst;
425         int ret;
426 
427         src = ethhdr->h_source;
428         dst = ethhdr->h_dest;
429 
430         /* if we got an hint! let's send the packet to this client (if any) */
431         if (dst_hint) {
432                 src = NULL;
433                 dst = dst_hint;
434         }
435         orig_node = batadv_transtable_search(bat_priv, src, dst, vid);
436 
437         ret = batadv_send_skb_unicast(bat_priv, skb, packet_type,
438                                       packet_subtype, orig_node, vid);
439 
440         if (orig_node)
441                 batadv_orig_node_put(orig_node);
442 
443         return ret;
444 }
445 
446 /**
447  * batadv_send_skb_via_gw() - send an skb via gateway lookup
448  * @bat_priv: the bat priv with all the soft interface information
449  * @skb: payload to send
450  * @vid: the vid to be used to search the translation table
451  *
452  * Look up the currently selected gateway. Wrap the given skb into a batman-adv
453  * unicast header and send this frame to this gateway node.
454  *
455  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
456  */
457 int batadv_send_skb_via_gw(struct batadv_priv *bat_priv, struct sk_buff *skb,
458                            unsigned short vid)
459 {
460         struct batadv_orig_node *orig_node;
461         int ret;
462 
463         orig_node = batadv_gw_get_selected_orig(bat_priv);
464         ret = batadv_send_skb_unicast(bat_priv, skb, BATADV_UNICAST_4ADDR,
465                                       BATADV_P_DATA, orig_node, vid);
466 
467         if (orig_node)
468                 batadv_orig_node_put(orig_node);
469 
470         return ret;
471 }
472 
473 /**
474  * batadv_forw_packet_free() - free a forwarding packet
475  * @forw_packet: The packet to free
476  * @dropped: whether the packet is freed because is is dropped
477  *
478  * This frees a forwarding packet and releases any resources it might
479  * have claimed.
480  */
481 void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet,
482                              bool dropped)
483 {
484         if (dropped)
485                 kfree_skb(forw_packet->skb);
486         else
487                 consume_skb(forw_packet->skb);
488 
489         if (forw_packet->if_incoming)
490                 batadv_hardif_put(forw_packet->if_incoming);
491         if (forw_packet->if_outgoing)
492                 batadv_hardif_put(forw_packet->if_outgoing);
493         if (forw_packet->queue_left)
494                 atomic_inc(forw_packet->queue_left);
495         kfree(forw_packet);
496 }
497 
498 /**
499  * batadv_forw_packet_alloc() - allocate a forwarding packet
500  * @if_incoming: The (optional) if_incoming to be grabbed
501  * @if_outgoing: The (optional) if_outgoing to be grabbed
502  * @queue_left: The (optional) queue counter to decrease
503  * @bat_priv: The bat_priv for the mesh of this forw_packet
504  * @skb: The raw packet this forwarding packet shall contain
505  *
506  * Allocates a forwarding packet and tries to get a reference to the
507  * (optional) if_incoming, if_outgoing and queue_left. If queue_left
508  * is NULL then bat_priv is optional, too.
509  *
510  * Return: An allocated forwarding packet on success, NULL otherwise.
511  */
512 struct batadv_forw_packet *
513 batadv_forw_packet_alloc(struct batadv_hard_iface *if_incoming,
514                          struct batadv_hard_iface *if_outgoing,
515                          atomic_t *queue_left,
516                          struct batadv_priv *bat_priv,
517                          struct sk_buff *skb)
518 {
519         struct batadv_forw_packet *forw_packet;
520         const char *qname;
521 
522         if (queue_left && !batadv_atomic_dec_not_zero(queue_left)) {
523                 qname = "unknown";
524 
525                 if (queue_left == &bat_priv->bcast_queue_left)
526                         qname = "bcast";
527 
528                 if (queue_left == &bat_priv->batman_queue_left)
529                         qname = "batman";
530 
531                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
532                            "%s queue is full\n", qname);
533 
534                 return NULL;
535         }
536 
537         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
538         if (!forw_packet)
539                 goto err;
540 
541         if (if_incoming)
542                 kref_get(&if_incoming->refcount);
543 
544         if (if_outgoing)
545                 kref_get(&if_outgoing->refcount);
546 
547         INIT_HLIST_NODE(&forw_packet->list);
548         INIT_HLIST_NODE(&forw_packet->cleanup_list);
549         forw_packet->skb = skb;
550         forw_packet->queue_left = queue_left;
551         forw_packet->if_incoming = if_incoming;
552         forw_packet->if_outgoing = if_outgoing;
553         forw_packet->num_packets = 0;
554 
555         return forw_packet;
556 
557 err:
558         if (queue_left)
559                 atomic_inc(queue_left);
560 
561         return NULL;
562 }
563 
564 /**
565  * batadv_forw_packet_was_stolen() - check whether someone stole this packet
566  * @forw_packet: the forwarding packet to check
567  *
568  * This function checks whether the given forwarding packet was claimed by
569  * someone else for free().
570  *
571  * Return: True if someone stole it, false otherwise.
572  */
573 static bool
574 batadv_forw_packet_was_stolen(struct batadv_forw_packet *forw_packet)
575 {
576         return !hlist_unhashed(&forw_packet->cleanup_list);
577 }
578 
579 /**
580  * batadv_forw_packet_steal() - claim a forw_packet for free()
581  * @forw_packet: the forwarding packet to steal
582  * @lock: a key to the store to steal from (e.g. forw_{bat,bcast}_list_lock)
583  *
584  * This function tries to steal a specific forw_packet from global
585  * visibility for the purpose of getting it for free(). That means
586  * the caller is *not* allowed to requeue it afterwards.
587  *
588  * Return: True if stealing was successful. False if someone else stole it
589  * before us.
590  */
591 bool batadv_forw_packet_steal(struct batadv_forw_packet *forw_packet,
592                               spinlock_t *lock)
593 {
594         /* did purging routine steal it earlier? */
595         spin_lock_bh(lock);
596         if (batadv_forw_packet_was_stolen(forw_packet)) {
597                 spin_unlock_bh(lock);
598                 return false;
599         }
600 
601         hlist_del_init(&forw_packet->list);
602 
603         /* Just to spot misuse of this function */
604         hlist_add_fake(&forw_packet->cleanup_list);
605 
606         spin_unlock_bh(lock);
607         return true;
608 }
609 
610 /**
611  * batadv_forw_packet_list_steal() - claim a list of forward packets for free()
612  * @forw_list: the to be stolen forward packets
613  * @cleanup_list: a backup pointer, to be able to dispose the packet later
614  * @hard_iface: the interface to steal forward packets from
615  *
616  * This function claims responsibility to free any forw_packet queued on the
617  * given hard_iface. If hard_iface is NULL forwarding packets on all hard
618  * interfaces will be claimed.
619  *
620  * The packets are being moved from the forw_list to the cleanup_list and
621  * by that allows already running threads to notice the claiming.
622  */
623 static void
624 batadv_forw_packet_list_steal(struct hlist_head *forw_list,
625                               struct hlist_head *cleanup_list,
626                               const struct batadv_hard_iface *hard_iface)
627 {
628         struct batadv_forw_packet *forw_packet;
629         struct hlist_node *safe_tmp_node;
630 
631         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
632                                   forw_list, list) {
633                 /* if purge_outstanding_packets() was called with an argument
634                  * we delete only packets belonging to the given interface
635                  */
636                 if (hard_iface &&
637                     forw_packet->if_incoming != hard_iface &&
638                     forw_packet->if_outgoing != hard_iface)
639                         continue;
640 
641                 hlist_del(&forw_packet->list);
642                 hlist_add_head(&forw_packet->cleanup_list, cleanup_list);
643         }
644 }
645 
646 /**
647  * batadv_forw_packet_list_free() - free a list of forward packets
648  * @head: a list of to be freed forw_packets
649  *
650  * This function cancels the scheduling of any packet in the provided list,
651  * waits for any possibly running packet forwarding thread to finish and
652  * finally, safely frees this forward packet.
653  *
654  * This function might sleep.
655  */
656 static void batadv_forw_packet_list_free(struct hlist_head *head)
657 {
658         struct batadv_forw_packet *forw_packet;
659         struct hlist_node *safe_tmp_node;
660 
661         hlist_for_each_entry_safe(forw_packet, safe_tmp_node, head,
662                                   cleanup_list) {
663                 cancel_delayed_work_sync(&forw_packet->delayed_work);
664 
665                 hlist_del(&forw_packet->cleanup_list);
666                 batadv_forw_packet_free(forw_packet, true);
667         }
668 }
669 
670 /**
671  * batadv_forw_packet_queue() - try to queue a forwarding packet
672  * @forw_packet: the forwarding packet to queue
673  * @lock: a key to the store (e.g. forw_{bat,bcast}_list_lock)
674  * @head: the shelve to queue it on (e.g. forw_{bat,bcast}_list)
675  * @send_time: timestamp (jiffies) when the packet is to be sent
676  *
677  * This function tries to (re)queue a forwarding packet. Requeuing
678  * is prevented if the according interface is shutting down
679  * (e.g. if batadv_forw_packet_list_steal() was called for this
680  * packet earlier).
681  *
682  * Calling batadv_forw_packet_queue() after a call to
683  * batadv_forw_packet_steal() is forbidden!
684  *
685  * Caller needs to ensure that forw_packet->delayed_work was initialized.
686  */
687 static void batadv_forw_packet_queue(struct batadv_forw_packet *forw_packet,
688                                      spinlock_t *lock, struct hlist_head *head,
689                                      unsigned long send_time)
690 {
691         spin_lock_bh(lock);
692 
693         /* did purging routine steal it from us? */
694         if (batadv_forw_packet_was_stolen(forw_packet)) {
695                 /* If you got it for free() without trouble, then
696                  * don't get back into the queue after stealing...
697                  */
698                 WARN_ONCE(hlist_fake(&forw_packet->cleanup_list),
699                           "Requeuing after batadv_forw_packet_steal() not allowed!\n");
700 
701                 spin_unlock_bh(lock);
702                 return;
703         }
704 
705         hlist_del_init(&forw_packet->list);
706         hlist_add_head(&forw_packet->list, head);
707 
708         queue_delayed_work(batadv_event_workqueue,
709                            &forw_packet->delayed_work,
710                            send_time - jiffies);
711         spin_unlock_bh(lock);
712 }
713 
714 /**
715  * batadv_forw_packet_bcast_queue() - try to queue a broadcast packet
716  * @bat_priv: the bat priv with all the soft interface information
717  * @forw_packet: the forwarding packet to queue
718  * @send_time: timestamp (jiffies) when the packet is to be sent
719  *
720  * This function tries to (re)queue a broadcast packet.
721  *
722  * Caller needs to ensure that forw_packet->delayed_work was initialized.
723  */
724 static void
725 batadv_forw_packet_bcast_queue(struct batadv_priv *bat_priv,
726                                struct batadv_forw_packet *forw_packet,
727                                unsigned long send_time)
728 {
729         batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bcast_list_lock,
730                                  &bat_priv->forw_bcast_list, send_time);
731 }
732 
733 /**
734  * batadv_forw_packet_ogmv1_queue() - try to queue an OGMv1 packet
735  * @bat_priv: the bat priv with all the soft interface information
736  * @forw_packet: the forwarding packet to queue
737  * @send_time: timestamp (jiffies) when the packet is to be sent
738  *
739  * This function tries to (re)queue an OGMv1 packet.
740  *
741  * Caller needs to ensure that forw_packet->delayed_work was initialized.
742  */
743 void batadv_forw_packet_ogmv1_queue(struct batadv_priv *bat_priv,
744                                     struct batadv_forw_packet *forw_packet,
745                                     unsigned long send_time)
746 {
747         batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bat_list_lock,
748                                  &bat_priv->forw_bat_list, send_time);
749 }
750 
751 /**
752  * batadv_add_bcast_packet_to_list() - queue broadcast packet for multiple sends
753  * @bat_priv: the bat priv with all the soft interface information
754  * @skb: broadcast packet to add
755  * @delay: number of jiffies to wait before sending
756  * @own_packet: true if it is a self-generated broadcast packet
757  *
758  * add a broadcast packet to the queue and setup timers. broadcast packets
759  * are sent multiple times to increase probability for being received.
760  *
761  * The skb is not consumed, so the caller should make sure that the
762  * skb is freed.
763  *
764  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
765  */
766 int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
767                                     const struct sk_buff *skb,
768                                     unsigned long delay,
769                                     bool own_packet)
770 {
771         struct batadv_hard_iface *primary_if;
772         struct batadv_forw_packet *forw_packet;
773         struct batadv_bcast_packet *bcast_packet;
774         struct sk_buff *newskb;
775 
776         primary_if = batadv_primary_if_get_selected(bat_priv);
777         if (!primary_if)
778                 goto err;
779 
780         newskb = skb_copy(skb, GFP_ATOMIC);
781         if (!newskb) {
782                 batadv_hardif_put(primary_if);
783                 goto err;
784         }
785 
786         forw_packet = batadv_forw_packet_alloc(primary_if, NULL,
787                                                &bat_priv->bcast_queue_left,
788                                                bat_priv, newskb);
789         batadv_hardif_put(primary_if);
790         if (!forw_packet)
791                 goto err_packet_free;
792 
793         /* as we have a copy now, it is safe to decrease the TTL */
794         bcast_packet = (struct batadv_bcast_packet *)newskb->data;
795         bcast_packet->ttl--;
796 
797         forw_packet->own = own_packet;
798 
799         INIT_DELAYED_WORK(&forw_packet->delayed_work,
800                           batadv_send_outstanding_bcast_packet);
801 
802         batadv_forw_packet_bcast_queue(bat_priv, forw_packet, jiffies + delay);
803         return NETDEV_TX_OK;
804 
805 err_packet_free:
806         kfree_skb(newskb);
807 err:
808         return NETDEV_TX_BUSY;
809 }
810 
811 /**
812  * batadv_forw_packet_bcasts_left() - check if a retransmission is necessary
813  * @forw_packet: the forwarding packet to check
814  * @hard_iface: the interface to check on
815  *
816  * Checks whether a given packet has any (re)transmissions left on the provided
817  * interface.
818  *
819  * hard_iface may be NULL: In that case the number of transmissions this skb had
820  * so far is compared with the maximum amount of retransmissions independent of
821  * any interface instead.
822  *
823  * Return: True if (re)transmissions are left, false otherwise.
824  */
825 static bool
826 batadv_forw_packet_bcasts_left(struct batadv_forw_packet *forw_packet,
827                                struct batadv_hard_iface *hard_iface)
828 {
829         unsigned int max;
830 
831         if (hard_iface)
832                 max = hard_iface->num_bcasts;
833         else
834                 max = BATADV_NUM_BCASTS_MAX;
835 
836         return BATADV_SKB_CB(forw_packet->skb)->num_bcasts < max;
837 }
838 
839 /**
840  * batadv_forw_packet_bcasts_inc() - increment retransmission counter of a
841  *  packet
842  * @forw_packet: the packet to increase the counter for
843  */
844 static void
845 batadv_forw_packet_bcasts_inc(struct batadv_forw_packet *forw_packet)
846 {
847         BATADV_SKB_CB(forw_packet->skb)->num_bcasts++;
848 }
849 
850 /**
851  * batadv_forw_packet_is_rebroadcast() - check packet for previous transmissions
852  * @forw_packet: the packet to check
853  *
854  * Return: True if this packet was transmitted before, false otherwise.
855  */
856 bool batadv_forw_packet_is_rebroadcast(struct batadv_forw_packet *forw_packet)
857 {
858         return BATADV_SKB_CB(forw_packet->skb)->num_bcasts > 0;
859 }
860 
861 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
862 {
863         struct batadv_hard_iface *hard_iface;
864         struct batadv_hardif_neigh_node *neigh_node;
865         struct delayed_work *delayed_work;
866         struct batadv_forw_packet *forw_packet;
867         struct batadv_bcast_packet *bcast_packet;
868         struct sk_buff *skb1;
869         struct net_device *soft_iface;
870         struct batadv_priv *bat_priv;
871         unsigned long send_time = jiffies + msecs_to_jiffies(5);
872         bool dropped = false;
873         u8 *neigh_addr;
874         u8 *orig_neigh;
875         int ret = 0;
876 
877         delayed_work = to_delayed_work(work);
878         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
879                                    delayed_work);
880         soft_iface = forw_packet->if_incoming->soft_iface;
881         bat_priv = netdev_priv(soft_iface);
882 
883         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
884                 dropped = true;
885                 goto out;
886         }
887 
888         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet)) {
889                 dropped = true;
890                 goto out;
891         }
892 
893         bcast_packet = (struct batadv_bcast_packet *)forw_packet->skb->data;
894 
895         /* rebroadcast packet */
896         rcu_read_lock();
897         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
898                 if (hard_iface->soft_iface != soft_iface)
899                         continue;
900 
901                 if (!batadv_forw_packet_bcasts_left(forw_packet, hard_iface))
902                         continue;
903 
904                 if (forw_packet->own) {
905                         neigh_node = NULL;
906                 } else {
907                         neigh_addr = eth_hdr(forw_packet->skb)->h_source;
908                         neigh_node = batadv_hardif_neigh_get(hard_iface,
909                                                              neigh_addr);
910                 }
911 
912                 orig_neigh = neigh_node ? neigh_node->orig : NULL;
913 
914                 ret = batadv_hardif_no_broadcast(hard_iface, bcast_packet->orig,
915                                                  orig_neigh);
916 
917                 if (ret) {
918                         char *type;
919 
920                         switch (ret) {
921                         case BATADV_HARDIF_BCAST_NORECIPIENT:
922                                 type = "no neighbor";
923                                 break;
924                         case BATADV_HARDIF_BCAST_DUPFWD:
925                                 type = "single neighbor is source";
926                                 break;
927                         case BATADV_HARDIF_BCAST_DUPORIG:
928                                 type = "single neighbor is originator";
929                                 break;
930                         default:
931                                 type = "unknown";
932                         }
933 
934                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "BCAST packet from orig %pM on %s suppressed: %s\n",
935                                    bcast_packet->orig,
936                                    hard_iface->net_dev->name, type);
937 
938                         if (neigh_node)
939                                 batadv_hardif_neigh_put(neigh_node);
940 
941                         continue;
942                 }
943 
944                 if (neigh_node)
945                         batadv_hardif_neigh_put(neigh_node);
946 
947                 if (!kref_get_unless_zero(&hard_iface->refcount))
948                         continue;
949 
950                 /* send a copy of the saved skb */
951                 skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
952                 if (skb1)
953                         batadv_send_broadcast_skb(skb1, hard_iface);
954 
955                 batadv_hardif_put(hard_iface);
956         }
957         rcu_read_unlock();
958 
959         batadv_forw_packet_bcasts_inc(forw_packet);
960 
961         /* if we still have some more bcasts to send */
962         if (batadv_forw_packet_bcasts_left(forw_packet, NULL)) {
963                 batadv_forw_packet_bcast_queue(bat_priv, forw_packet,
964                                                send_time);
965                 return;
966         }
967 
968 out:
969         /* do we get something for free()? */
970         if (batadv_forw_packet_steal(forw_packet,
971                                      &bat_priv->forw_bcast_list_lock))
972                 batadv_forw_packet_free(forw_packet, dropped);
973 }
974 
975 /**
976  * batadv_purge_outstanding_packets() - stop/purge scheduled bcast/OGMv1 packets
977  * @bat_priv: the bat priv with all the soft interface information
978  * @hard_iface: the hard interface to cancel and purge bcast/ogm packets on
979  *
980  * This method cancels and purges any broadcast and OGMv1 packet on the given
981  * hard_iface. If hard_iface is NULL, broadcast and OGMv1 packets on all hard
982  * interfaces will be canceled and purged.
983  *
984  * This function might sleep.
985  */
986 void
987 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
988                                  const struct batadv_hard_iface *hard_iface)
989 {
990         struct hlist_head head = HLIST_HEAD_INIT;
991 
992         if (hard_iface)
993                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
994                            "%s(): %s\n",
995                            __func__, hard_iface->net_dev->name);
996         else
997                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
998                            "%s()\n", __func__);
999 
1000         /* claim bcast list for free() */
1001         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
1002         batadv_forw_packet_list_steal(&bat_priv->forw_bcast_list, &head,
1003                                       hard_iface);
1004         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
1005 
1006         /* claim batman packet list for free() */
1007         spin_lock_bh(&bat_priv->forw_bat_list_lock);
1008         batadv_forw_packet_list_steal(&bat_priv->forw_bat_list, &head,
1009                                       hard_iface);
1010         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
1011 
1012         /* then cancel or wait for packet workers to finish and free */
1013         batadv_forw_packet_list_free(&head);
1014 }
1015 

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