1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) B.A.T.M.A.N. contributors:
3 *
4 * Marek Lindner, Simon Wunderlich
5 */
6
7#include "send.h"
8#include "main.h"
9
10#include <linux/atomic.h>
11#include <linux/bug.h>
12#include <linux/byteorder/generic.h>
13#include <linux/container_of.h>
14#include <linux/errno.h>
15#include <linux/etherdevice.h>
16#include <linux/gfp.h>
17#include <linux/if.h>
18#include <linux/if_ether.h>
19#include <linux/jiffies.h>
20#include <linux/kref.h>
21#include <linux/list.h>
22#include <linux/netdevice.h>
23#include <linux/printk.h>
24#include <linux/rcupdate.h>
25#include <linux/skbuff.h>
26#include <linux/slab.h>
27#include <linux/spinlock.h>
28#include <linux/stddef.h>
29#include <linux/workqueue.h>
30
31#include "distributed-arp-table.h"
32#include "fragmentation.h"
33#include "gateway_client.h"
34#include "hard-interface.h"
35#include "log.h"
36#include "mesh-interface.h"
37#include "originator.h"
38#include "routing.h"
39#include "translation-table.h"
40
41static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
42
43/**
44 * batadv_send_skb_packet() - send an already prepared packet
45 * @skb: the packet to send
46 * @hard_iface: the interface to use to send the broadcast packet
47 * @dst_addr: the payload destination
48 *
49 * Send out an already prepared packet to the given neighbor or broadcast it
50 * using the specified interface. Either hard_iface or neigh_node must be not
51 * NULL.
52 * If neigh_node is NULL, then the packet is broadcasted using hard_iface,
53 * otherwise it is sent as unicast to the given neighbor.
54 *
55 * Regardless of the return value, the skb is consumed.
56 *
57 * Return: A negative errno code is returned on a failure. A success does not
58 * guarantee the frame will be transmitted as it may be dropped due
59 * to congestion or traffic shaping.
60 */
61int batadv_send_skb_packet(struct sk_buff *skb,
62 struct batadv_hard_iface *hard_iface,
63 const u8 *dst_addr)
64{
65 struct ethhdr *ethhdr;
66 int ret;
67
68 if (hard_iface->if_status != BATADV_IF_ACTIVE)
69 goto send_skb_err;
70
71 if (unlikely(!hard_iface->net_dev))
72 goto send_skb_err;
73
74 if (!(hard_iface->net_dev->flags & IFF_UP)) {
75 pr_warn("Interface %s is not up - can't send packet via that interface!\n",
76 hard_iface->net_dev->name);
77 goto send_skb_err;
78 }
79
80 /* push to the ethernet header. */
81 if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
82 goto send_skb_err;
83
84 skb_reset_mac_header(skb);
85
86 ethhdr = eth_hdr(skb);
87 ether_addr_copy(dst: ethhdr->h_source, src: hard_iface->net_dev->dev_addr);
88 ether_addr_copy(dst: ethhdr->h_dest, src: dst_addr);
89 ethhdr->h_proto = htons(ETH_P_BATMAN);
90
91 skb_set_network_header(skb, ETH_HLEN);
92 skb->protocol = htons(ETH_P_BATMAN);
93
94 skb->dev = hard_iface->net_dev;
95
96 /* dev_queue_xmit() returns a negative result on error. However on
97 * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
98 * (which is > 0). This will not be treated as an error.
99 */
100 ret = dev_queue_xmit(skb);
101 return net_xmit_eval(ret);
102send_skb_err:
103 kfree_skb(skb);
104 return NET_XMIT_DROP;
105}
106
107/**
108 * batadv_send_broadcast_skb() - Send broadcast packet via hard interface
109 * @skb: packet to be transmitted (with batadv header and no outer eth header)
110 * @hard_iface: outgoing interface
111 *
112 * Return: A negative errno code is returned on a failure. A success does not
113 * guarantee the frame will be transmitted as it may be dropped due
114 * to congestion or traffic shaping.
115 */
116int batadv_send_broadcast_skb(struct sk_buff *skb,
117 struct batadv_hard_iface *hard_iface)
118{
119 static const u8 broadcast_addr[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
120
121 return batadv_send_skb_packet(skb, hard_iface, dst_addr: broadcast_addr);
122}
123
124/**
125 * batadv_send_unicast_skb() - Send unicast packet to neighbor
126 * @skb: packet to be transmitted (with batadv header and no outer eth header)
127 * @neigh: neighbor which is used as next hop to destination
128 *
129 * Return: A negative errno code is returned on a failure. A success does not
130 * guarantee the frame will be transmitted as it may be dropped due
131 * to congestion or traffic shaping.
132 */
133int batadv_send_unicast_skb(struct sk_buff *skb,
134 struct batadv_neigh_node *neigh)
135{
136#ifdef CONFIG_BATMAN_ADV_BATMAN_V
137 struct batadv_hardif_neigh_node *hardif_neigh;
138#endif
139 int ret;
140
141 ret = batadv_send_skb_packet(skb, hard_iface: neigh->if_incoming, dst_addr: neigh->addr);
142
143#ifdef CONFIG_BATMAN_ADV_BATMAN_V
144 hardif_neigh = batadv_hardif_neigh_get(hard_iface: neigh->if_incoming, neigh_addr: neigh->addr);
145
146 if (hardif_neigh && ret != NET_XMIT_DROP)
147 hardif_neigh->bat_v.last_unicast_tx = jiffies;
148
149 batadv_hardif_neigh_put(hardif_neigh);
150#endif
151
152 return ret;
153}
154
155/**
156 * batadv_send_skb_to_orig() - Lookup next-hop and transmit skb.
157 * @skb: Packet to be transmitted.
158 * @orig_node: Final destination of the packet.
159 * @recv_if: Interface used when receiving the packet (can be NULL).
160 *
161 * Looks up the best next-hop towards the passed originator and passes the
162 * skb on for preparation of MAC header. If the packet originated from this
163 * host, NULL can be passed as recv_if and no interface alternating is
164 * attempted.
165 *
166 * Return: negative errno code on a failure, -EINPROGRESS if the skb is
167 * buffered for later transmit or the NET_XMIT status returned by the
168 * lower routine if the packet has been passed down.
169 */
170int batadv_send_skb_to_orig(struct sk_buff *skb,
171 struct batadv_orig_node *orig_node,
172 struct batadv_hard_iface *recv_if)
173{
174 struct batadv_priv *bat_priv = orig_node->bat_priv;
175 struct batadv_neigh_node *neigh_node;
176 int ret;
177
178 /* batadv_find_router() increases neigh_nodes refcount if found. */
179 neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
180 if (!neigh_node) {
181 ret = -EINVAL;
182 goto free_skb;
183 }
184
185 /* Check if the skb is too large to send in one piece and fragment
186 * it if needed.
187 */
188 if (atomic_read(v: &bat_priv->fragmentation) &&
189 skb->len > neigh_node->if_incoming->net_dev->mtu) {
190 /* Fragment and send packet. */
191 ret = batadv_frag_send_packet(skb, orig_node, neigh_node);
192 /* skb was consumed */
193 skb = NULL;
194
195 goto put_neigh_node;
196 }
197
198 ret = batadv_send_unicast_skb(skb, neigh: neigh_node);
199
200 /* skb was consumed */
201 skb = NULL;
202
203put_neigh_node:
204 batadv_neigh_node_put(neigh_node);
205free_skb:
206 kfree_skb(skb);
207
208 return ret;
209}
210
211/**
212 * batadv_send_skb_push_fill_unicast() - extend the buffer and initialize the
213 * common fields for unicast packets
214 * @skb: the skb carrying the unicast header to initialize
215 * @hdr_size: amount of bytes to push at the beginning of the skb
216 * @orig_node: the destination node
217 *
218 * Return: false if the buffer extension was not possible or true otherwise.
219 */
220static bool
221batadv_send_skb_push_fill_unicast(struct sk_buff *skb, int hdr_size,
222 struct batadv_orig_node *orig_node)
223{
224 struct batadv_unicast_packet *unicast_packet;
225 u8 ttvn = (u8)atomic_read(v: &orig_node->last_ttvn);
226
227 if (batadv_skb_head_push(skb, len: hdr_size) < 0)
228 return false;
229
230 unicast_packet = (struct batadv_unicast_packet *)skb->data;
231 unicast_packet->version = BATADV_COMPAT_VERSION;
232 /* batman packet type: unicast */
233 unicast_packet->packet_type = BATADV_UNICAST;
234 /* set unicast ttl */
235 unicast_packet->ttl = BATADV_TTL;
236 /* copy the destination for faster routing */
237 ether_addr_copy(dst: unicast_packet->dest, src: orig_node->orig);
238 /* set the destination tt version number */
239 unicast_packet->ttvn = ttvn;
240
241 return true;
242}
243
244/**
245 * batadv_send_skb_prepare_unicast() - encapsulate an skb with a unicast header
246 * @skb: the skb containing the payload to encapsulate
247 * @orig_node: the destination node
248 *
249 * Return: false if the payload could not be encapsulated or true otherwise.
250 */
251static bool batadv_send_skb_prepare_unicast(struct sk_buff *skb,
252 struct batadv_orig_node *orig_node)
253{
254 size_t uni_size = sizeof(struct batadv_unicast_packet);
255
256 return batadv_send_skb_push_fill_unicast(skb, hdr_size: uni_size, orig_node);
257}
258
259/**
260 * batadv_send_skb_prepare_unicast_4addr() - encapsulate an skb with a
261 * unicast 4addr header
262 * @bat_priv: the bat priv with all the mesh interface information
263 * @skb: the skb containing the payload to encapsulate
264 * @orig: the destination node
265 * @packet_subtype: the unicast 4addr packet subtype to use
266 *
267 * Return: false if the payload could not be encapsulated or true otherwise.
268 */
269bool batadv_send_skb_prepare_unicast_4addr(struct batadv_priv *bat_priv,
270 struct sk_buff *skb,
271 struct batadv_orig_node *orig,
272 int packet_subtype)
273{
274 struct batadv_hard_iface *primary_if;
275 struct batadv_unicast_4addr_packet *uc_4addr_packet;
276 bool ret = false;
277
278 primary_if = batadv_primary_if_get_selected(bat_priv);
279 if (!primary_if)
280 goto out;
281
282 /* Pull the header space and fill the unicast_packet substructure.
283 * We can do that because the first member of the uc_4addr_packet
284 * is of type struct unicast_packet
285 */
286 if (!batadv_send_skb_push_fill_unicast(skb, hdr_size: sizeof(*uc_4addr_packet),
287 orig_node: orig))
288 goto out;
289
290 uc_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
291 uc_4addr_packet->u.packet_type = BATADV_UNICAST_4ADDR;
292 ether_addr_copy(dst: uc_4addr_packet->src, src: primary_if->net_dev->dev_addr);
293 uc_4addr_packet->subtype = packet_subtype;
294 uc_4addr_packet->reserved = 0;
295
296 ret = true;
297out:
298 batadv_hardif_put(hard_iface: primary_if);
299 return ret;
300}
301
302/**
303 * batadv_send_skb_unicast() - encapsulate and send an skb via unicast
304 * @bat_priv: the bat priv with all the mesh interface information
305 * @skb: payload to send
306 * @packet_type: the batman unicast packet type to use
307 * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
308 * 4addr packets)
309 * @orig_node: the originator to send the packet to
310 * @vid: the vid to be used to search the translation table
311 *
312 * Wrap the given skb into a batman-adv unicast or unicast-4addr header
313 * depending on whether BATADV_UNICAST or BATADV_UNICAST_4ADDR was supplied
314 * as packet_type. Then send this frame to the given orig_node.
315 *
316 * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
317 */
318int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
319 struct sk_buff *skb, int packet_type,
320 int packet_subtype,
321 struct batadv_orig_node *orig_node,
322 unsigned short vid)
323{
324 struct batadv_unicast_packet *unicast_packet;
325 struct ethhdr *ethhdr;
326 int ret = NET_XMIT_DROP;
327
328 if (!orig_node)
329 goto out;
330
331 switch (packet_type) {
332 case BATADV_UNICAST:
333 if (!batadv_send_skb_prepare_unicast(skb, orig_node))
334 goto out;
335 break;
336 case BATADV_UNICAST_4ADDR:
337 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
338 orig: orig_node,
339 packet_subtype))
340 goto out;
341 break;
342 default:
343 /* this function supports UNICAST and UNICAST_4ADDR only. It
344 * should never be invoked with any other packet type
345 */
346 goto out;
347 }
348
349 /* skb->data might have been reallocated by
350 * batadv_send_skb_prepare_unicast{,_4addr}()
351 */
352 ethhdr = eth_hdr(skb);
353 unicast_packet = (struct batadv_unicast_packet *)skb->data;
354
355 /* inform the destination node that we are still missing a correct route
356 * for this client. The destination will receive this packet and will
357 * try to reroute it because the ttvn contained in the header is less
358 * than the current one
359 */
360 if (batadv_tt_global_client_is_roaming(bat_priv, addr: ethhdr->h_dest, vid))
361 unicast_packet->ttvn = unicast_packet->ttvn - 1;
362
363 ret = batadv_send_skb_to_orig(skb, orig_node, NULL);
364 /* skb was consumed */
365 skb = NULL;
366
367out:
368 kfree_skb(skb);
369 return ret;
370}
371
372/**
373 * batadv_send_skb_via_tt_generic() - send an skb via TT lookup
374 * @bat_priv: the bat priv with all the mesh interface information
375 * @skb: payload to send
376 * @packet_type: the batman unicast packet type to use
377 * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
378 * 4addr packets)
379 * @dst_hint: can be used to override the destination contained in the skb
380 * @vid: the vid to be used to search the translation table
381 *
382 * Look up the recipient node for the destination address in the ethernet
383 * header via the translation table. Wrap the given skb into a batman-adv
384 * unicast or unicast-4addr header depending on whether BATADV_UNICAST or
385 * BATADV_UNICAST_4ADDR was supplied as packet_type. Then send this frame
386 * to the according destination node.
387 *
388 * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
389 */
390int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
391 struct sk_buff *skb, int packet_type,
392 int packet_subtype, u8 *dst_hint,
393 unsigned short vid)
394{
395 struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
396 struct batadv_orig_node *orig_node;
397 u8 *src, *dst;
398 int ret;
399
400 src = ethhdr->h_source;
401 dst = ethhdr->h_dest;
402
403 /* if we got an hint! let's send the packet to this client (if any) */
404 if (dst_hint) {
405 src = NULL;
406 dst = dst_hint;
407 }
408 orig_node = batadv_transtable_search(bat_priv, src, addr: dst, vid);
409
410 ret = batadv_send_skb_unicast(bat_priv, skb, packet_type,
411 packet_subtype, orig_node, vid);
412
413 batadv_orig_node_put(orig_node);
414
415 return ret;
416}
417
418/**
419 * batadv_send_skb_via_gw() - send an skb via gateway lookup
420 * @bat_priv: the bat priv with all the mesh interface information
421 * @skb: payload to send
422 * @vid: the vid to be used to search the translation table
423 *
424 * Look up the currently selected gateway. Wrap the given skb into a batman-adv
425 * unicast header and send this frame to this gateway node.
426 *
427 * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
428 */
429int batadv_send_skb_via_gw(struct batadv_priv *bat_priv, struct sk_buff *skb,
430 unsigned short vid)
431{
432 struct batadv_orig_node *orig_node;
433 int ret;
434
435 orig_node = batadv_gw_get_selected_orig(bat_priv);
436 ret = batadv_send_skb_unicast(bat_priv, skb, packet_type: BATADV_UNICAST_4ADDR,
437 packet_subtype: BATADV_P_DATA, orig_node, vid);
438
439 batadv_orig_node_put(orig_node);
440
441 return ret;
442}
443
444/**
445 * batadv_forw_packet_free() - free a forwarding packet
446 * @forw_packet: The packet to free
447 * @dropped: whether the packet is freed because is dropped
448 *
449 * This frees a forwarding packet and releases any resources it might
450 * have claimed.
451 */
452void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet,
453 bool dropped)
454{
455 if (dropped)
456 kfree_skb(skb: forw_packet->skb);
457 else
458 consume_skb(skb: forw_packet->skb);
459
460 batadv_hardif_put(hard_iface: forw_packet->if_incoming);
461 batadv_hardif_put(hard_iface: forw_packet->if_outgoing);
462 if (forw_packet->queue_left)
463 atomic_inc(v: forw_packet->queue_left);
464 kfree(objp: forw_packet);
465}
466
467/**
468 * batadv_forw_packet_alloc() - allocate a forwarding packet
469 * @if_incoming: The (optional) if_incoming to be grabbed
470 * @if_outgoing: The (optional) if_outgoing to be grabbed
471 * @queue_left: The (optional) queue counter to decrease
472 * @bat_priv: The bat_priv for the mesh of this forw_packet
473 * @skb: The raw packet this forwarding packet shall contain
474 *
475 * Allocates a forwarding packet and tries to get a reference to the
476 * (optional) if_incoming, if_outgoing and queue_left. If queue_left
477 * is NULL then bat_priv is optional, too.
478 *
479 * Return: An allocated forwarding packet on success, NULL otherwise.
480 */
481struct batadv_forw_packet *
482batadv_forw_packet_alloc(struct batadv_hard_iface *if_incoming,
483 struct batadv_hard_iface *if_outgoing,
484 atomic_t *queue_left,
485 struct batadv_priv *bat_priv,
486 struct sk_buff *skb)
487{
488 struct batadv_forw_packet *forw_packet;
489 const char *qname;
490
491 if (queue_left && !batadv_atomic_dec_not_zero(queue_left)) {
492 qname = "unknown";
493
494 if (queue_left == &bat_priv->bcast_queue_left)
495 qname = "bcast";
496
497 if (queue_left == &bat_priv->batman_queue_left)
498 qname = "batman";
499
500 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
501 "%s queue is full\n", qname);
502
503 return NULL;
504 }
505
506 forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
507 if (!forw_packet)
508 goto err;
509
510 if (if_incoming)
511 kref_get(kref: &if_incoming->refcount);
512
513 if (if_outgoing)
514 kref_get(kref: &if_outgoing->refcount);
515
516 INIT_HLIST_NODE(h: &forw_packet->list);
517 INIT_HLIST_NODE(h: &forw_packet->cleanup_list);
518 forw_packet->skb = skb;
519 forw_packet->queue_left = queue_left;
520 forw_packet->if_incoming = if_incoming;
521 forw_packet->if_outgoing = if_outgoing;
522 forw_packet->num_packets = 1;
523
524 return forw_packet;
525
526err:
527 if (queue_left)
528 atomic_inc(v: queue_left);
529
530 return NULL;
531}
532
533/**
534 * batadv_forw_packet_was_stolen() - check whether someone stole this packet
535 * @forw_packet: the forwarding packet to check
536 *
537 * This function checks whether the given forwarding packet was claimed by
538 * someone else for free().
539 *
540 * Return: True if someone stole it, false otherwise.
541 */
542static bool
543batadv_forw_packet_was_stolen(struct batadv_forw_packet *forw_packet)
544{
545 return !hlist_unhashed(h: &forw_packet->cleanup_list);
546}
547
548/**
549 * batadv_forw_packet_steal() - claim a forw_packet for free()
550 * @forw_packet: the forwarding packet to steal
551 * @lock: a key to the store to steal from (e.g. forw_{bat,bcast}_list_lock)
552 *
553 * This function tries to steal a specific forw_packet from global
554 * visibility for the purpose of getting it for free(). That means
555 * the caller is *not* allowed to requeue it afterwards.
556 *
557 * Return: True if stealing was successful. False if someone else stole it
558 * before us.
559 */
560bool batadv_forw_packet_steal(struct batadv_forw_packet *forw_packet,
561 spinlock_t *lock)
562{
563 /* did purging routine steal it earlier? */
564 spin_lock_bh(lock);
565 if (batadv_forw_packet_was_stolen(forw_packet)) {
566 spin_unlock_bh(lock);
567 return false;
568 }
569
570 hlist_del_init(n: &forw_packet->list);
571
572 /* Just to spot misuse of this function */
573 hlist_add_fake(n: &forw_packet->cleanup_list);
574
575 spin_unlock_bh(lock);
576 return true;
577}
578
579/**
580 * batadv_forw_packet_list_steal() - claim a list of forward packets for free()
581 * @forw_list: the to be stolen forward packets
582 * @cleanup_list: a backup pointer, to be able to dispose the packet later
583 * @hard_iface: the interface to steal forward packets from
584 *
585 * This function claims responsibility to free any forw_packet queued on the
586 * given hard_iface. If hard_iface is NULL forwarding packets on all hard
587 * interfaces will be claimed.
588 *
589 * The packets are being moved from the forw_list to the cleanup_list. This
590 * makes it possible for already running threads to notice the claim.
591 */
592static void
593batadv_forw_packet_list_steal(struct hlist_head *forw_list,
594 struct hlist_head *cleanup_list,
595 const struct batadv_hard_iface *hard_iface)
596{
597 struct batadv_forw_packet *forw_packet;
598 struct hlist_node *safe_tmp_node;
599
600 hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
601 forw_list, list) {
602 /* if purge_outstanding_packets() was called with an argument
603 * we delete only packets belonging to the given interface
604 */
605 if (hard_iface &&
606 forw_packet->if_incoming != hard_iface &&
607 forw_packet->if_outgoing != hard_iface)
608 continue;
609
610 hlist_del(n: &forw_packet->list);
611 hlist_add_head(n: &forw_packet->cleanup_list, h: cleanup_list);
612 }
613}
614
615/**
616 * batadv_forw_packet_list_free() - free a list of forward packets
617 * @head: a list of to be freed forw_packets
618 *
619 * This function cancels the scheduling of any packet in the provided list,
620 * waits for any possibly running packet forwarding thread to finish and
621 * finally, safely frees this forward packet.
622 *
623 * This function might sleep.
624 */
625static void batadv_forw_packet_list_free(struct hlist_head *head)
626{
627 struct batadv_forw_packet *forw_packet;
628 struct hlist_node *safe_tmp_node;
629
630 hlist_for_each_entry_safe(forw_packet, safe_tmp_node, head,
631 cleanup_list) {
632 cancel_delayed_work_sync(dwork: &forw_packet->delayed_work);
633
634 hlist_del(n: &forw_packet->cleanup_list);
635 batadv_forw_packet_free(forw_packet, dropped: true);
636 }
637}
638
639/**
640 * batadv_forw_packet_queue() - try to queue a forwarding packet
641 * @forw_packet: the forwarding packet to queue
642 * @lock: a key to the store (e.g. forw_{bat,bcast}_list_lock)
643 * @head: the shelve to queue it on (e.g. forw_{bat,bcast}_list)
644 * @send_time: timestamp (jiffies) when the packet is to be sent
645 *
646 * This function tries to (re)queue a forwarding packet. Requeuing
647 * is prevented if the according interface is shutting down
648 * (e.g. if batadv_forw_packet_list_steal() was called for this
649 * packet earlier).
650 *
651 * Calling batadv_forw_packet_queue() after a call to
652 * batadv_forw_packet_steal() is forbidden!
653 *
654 * Caller needs to ensure that forw_packet->delayed_work was initialized.
655 */
656static void batadv_forw_packet_queue(struct batadv_forw_packet *forw_packet,
657 spinlock_t *lock, struct hlist_head *head,
658 unsigned long send_time)
659{
660 spin_lock_bh(lock);
661
662 /* did purging routine steal it from us? */
663 if (batadv_forw_packet_was_stolen(forw_packet)) {
664 /* If you got it for free() without trouble, then
665 * don't get back into the queue after stealing...
666 */
667 WARN_ONCE(hlist_fake(&forw_packet->cleanup_list),
668 "Requeuing after batadv_forw_packet_steal() not allowed!\n");
669
670 spin_unlock_bh(lock);
671 return;
672 }
673
674 hlist_del_init(n: &forw_packet->list);
675 hlist_add_head(n: &forw_packet->list, h: head);
676
677 queue_delayed_work(wq: batadv_event_workqueue,
678 dwork: &forw_packet->delayed_work,
679 delay: send_time - jiffies);
680 spin_unlock_bh(lock);
681}
682
683/**
684 * batadv_forw_packet_bcast_queue() - try to queue a broadcast packet
685 * @bat_priv: the bat priv with all the mesh interface information
686 * @forw_packet: the forwarding packet to queue
687 * @send_time: timestamp (jiffies) when the packet is to be sent
688 *
689 * This function tries to (re)queue a broadcast packet.
690 *
691 * Caller needs to ensure that forw_packet->delayed_work was initialized.
692 */
693static void
694batadv_forw_packet_bcast_queue(struct batadv_priv *bat_priv,
695 struct batadv_forw_packet *forw_packet,
696 unsigned long send_time)
697{
698 batadv_forw_packet_queue(forw_packet, lock: &bat_priv->forw_bcast_list_lock,
699 head: &bat_priv->forw_bcast_list, send_time);
700}
701
702/**
703 * batadv_forw_packet_ogmv1_queue() - try to queue an OGMv1 packet
704 * @bat_priv: the bat priv with all the mesh interface information
705 * @forw_packet: the forwarding packet to queue
706 * @send_time: timestamp (jiffies) when the packet is to be sent
707 *
708 * This function tries to (re)queue an OGMv1 packet.
709 *
710 * Caller needs to ensure that forw_packet->delayed_work was initialized.
711 */
712void batadv_forw_packet_ogmv1_queue(struct batadv_priv *bat_priv,
713 struct batadv_forw_packet *forw_packet,
714 unsigned long send_time)
715{
716 batadv_forw_packet_queue(forw_packet, lock: &bat_priv->forw_bat_list_lock,
717 head: &bat_priv->forw_bat_list, send_time);
718}
719
720/**
721 * batadv_forw_bcast_packet_to_list() - queue broadcast packet for transmissions
722 * @bat_priv: the bat priv with all the mesh interface information
723 * @skb: broadcast packet to add
724 * @delay: number of jiffies to wait before sending
725 * @own_packet: true if it is a self-generated broadcast packet
726 * @if_in: the interface where the packet was received on
727 * @if_out: the outgoing interface to queue on
728 *
729 * Adds a broadcast packet to the queue and sets up timers. Broadcast packets
730 * are sent multiple times to increase probability for being received.
731 *
732 * This call clones the given skb, hence the caller needs to take into
733 * account that the data segment of the original skb might not be
734 * modifiable anymore.
735 *
736 * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
737 */
738static int batadv_forw_bcast_packet_to_list(struct batadv_priv *bat_priv,
739 struct sk_buff *skb,
740 unsigned long delay,
741 bool own_packet,
742 struct batadv_hard_iface *if_in,
743 struct batadv_hard_iface *if_out)
744{
745 struct batadv_forw_packet *forw_packet;
746 unsigned long send_time = jiffies;
747 struct sk_buff *newskb;
748
749 newskb = skb_clone(skb, GFP_ATOMIC);
750 if (!newskb)
751 goto err;
752
753 forw_packet = batadv_forw_packet_alloc(if_incoming: if_in, if_outgoing: if_out,
754 queue_left: &bat_priv->bcast_queue_left,
755 bat_priv, skb: newskb);
756 if (!forw_packet)
757 goto err_packet_free;
758
759 forw_packet->own = own_packet;
760
761 INIT_DELAYED_WORK(&forw_packet->delayed_work,
762 batadv_send_outstanding_bcast_packet);
763
764 send_time += delay ? delay : msecs_to_jiffies(m: 5);
765
766 batadv_forw_packet_bcast_queue(bat_priv, forw_packet, send_time);
767 return NETDEV_TX_OK;
768
769err_packet_free:
770 kfree_skb(skb: newskb);
771err:
772 return NETDEV_TX_BUSY;
773}
774
775/**
776 * batadv_forw_bcast_packet_if() - forward and queue a broadcast packet
777 * @bat_priv: the bat priv with all the mesh interface information
778 * @skb: broadcast packet to add
779 * @delay: number of jiffies to wait before sending
780 * @own_packet: true if it is a self-generated broadcast packet
781 * @if_in: the interface where the packet was received on
782 * @if_out: the outgoing interface to forward to
783 *
784 * Transmits a broadcast packet on the specified interface either immediately
785 * or if a delay is given after that. Furthermore, queues additional
786 * retransmissions if this interface is a wireless one.
787 *
788 * This call clones the given skb, hence the caller needs to take into
789 * account that the data segment of the original skb might not be
790 * modifiable anymore.
791 *
792 * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
793 */
794static int batadv_forw_bcast_packet_if(struct batadv_priv *bat_priv,
795 struct sk_buff *skb,
796 unsigned long delay,
797 bool own_packet,
798 struct batadv_hard_iface *if_in,
799 struct batadv_hard_iface *if_out)
800{
801 unsigned int num_bcasts = if_out->num_bcasts;
802 struct sk_buff *newskb;
803 int ret = NETDEV_TX_OK;
804
805 if (!delay) {
806 newskb = skb_clone(skb, GFP_ATOMIC);
807 if (!newskb)
808 return NETDEV_TX_BUSY;
809
810 batadv_send_broadcast_skb(skb: newskb, hard_iface: if_out);
811 num_bcasts--;
812 }
813
814 /* delayed broadcast or rebroadcasts? */
815 if (num_bcasts >= 1) {
816 BATADV_SKB_CB(skb)->num_bcasts = num_bcasts;
817
818 ret = batadv_forw_bcast_packet_to_list(bat_priv, skb, delay,
819 own_packet, if_in,
820 if_out);
821 }
822
823 return ret;
824}
825
826/**
827 * batadv_send_no_broadcast() - check whether (re)broadcast is necessary
828 * @bat_priv: the bat priv with all the mesh interface information
829 * @skb: broadcast packet to check
830 * @own_packet: true if it is a self-generated broadcast packet
831 * @if_out: the outgoing interface checked and considered for (re)broadcast
832 *
833 * Return: False if a packet needs to be (re)broadcasted on the given interface,
834 * true otherwise.
835 */
836static bool batadv_send_no_broadcast(struct batadv_priv *bat_priv,
837 struct sk_buff *skb, bool own_packet,
838 struct batadv_hard_iface *if_out)
839{
840 struct batadv_hardif_neigh_node *neigh_node = NULL;
841 struct batadv_bcast_packet *bcast_packet;
842 u8 *orig_neigh;
843 u8 *neigh_addr;
844 char *type;
845 int ret;
846
847 if (!own_packet) {
848 neigh_addr = eth_hdr(skb)->h_source;
849 neigh_node = batadv_hardif_neigh_get(hard_iface: if_out,
850 neigh_addr);
851 }
852
853 bcast_packet = (struct batadv_bcast_packet *)skb->data;
854 orig_neigh = neigh_node ? neigh_node->orig : NULL;
855
856 ret = batadv_hardif_no_broadcast(if_outgoing: if_out, orig_addr: bcast_packet->orig,
857 orig_neigh);
858
859 batadv_hardif_neigh_put(hardif_neigh: neigh_node);
860
861 /* ok, may broadcast */
862 if (!ret)
863 return false;
864
865 /* no broadcast */
866 switch (ret) {
867 case BATADV_HARDIF_BCAST_NORECIPIENT:
868 type = "no neighbor";
869 break;
870 case BATADV_HARDIF_BCAST_DUPFWD:
871 type = "single neighbor is source";
872 break;
873 case BATADV_HARDIF_BCAST_DUPORIG:
874 type = "single neighbor is originator";
875 break;
876 default:
877 type = "unknown";
878 }
879
880 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
881 "BCAST packet from orig %pM on %s suppressed: %s\n",
882 bcast_packet->orig,
883 if_out->net_dev->name, type);
884
885 return true;
886}
887
888/**
889 * __batadv_forw_bcast_packet() - forward and queue a broadcast packet
890 * @bat_priv: the bat priv with all the mesh interface information
891 * @skb: broadcast packet to add
892 * @delay: number of jiffies to wait before sending
893 * @own_packet: true if it is a self-generated broadcast packet
894 *
895 * Transmits a broadcast packet either immediately or if a delay is given
896 * after that. Furthermore, queues additional retransmissions on wireless
897 * interfaces.
898 *
899 * This call clones the given skb, hence the caller needs to take into
900 * account that the data segment of the given skb might not be
901 * modifiable anymore.
902 *
903 * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
904 */
905static int __batadv_forw_bcast_packet(struct batadv_priv *bat_priv,
906 struct sk_buff *skb,
907 unsigned long delay,
908 bool own_packet)
909{
910 struct batadv_hard_iface *hard_iface;
911 struct batadv_hard_iface *primary_if;
912 struct list_head *iter;
913 int ret = NETDEV_TX_OK;
914
915 primary_if = batadv_primary_if_get_selected(bat_priv);
916 if (!primary_if)
917 return NETDEV_TX_BUSY;
918
919 rcu_read_lock();
920 netdev_for_each_lower_private_rcu(bat_priv->mesh_iface, hard_iface, iter) {
921 if (!kref_get_unless_zero(kref: &hard_iface->refcount))
922 continue;
923
924 if (batadv_send_no_broadcast(bat_priv, skb, own_packet,
925 if_out: hard_iface)) {
926 batadv_hardif_put(hard_iface);
927 continue;
928 }
929
930 ret = batadv_forw_bcast_packet_if(bat_priv, skb, delay,
931 own_packet, if_in: primary_if,
932 if_out: hard_iface);
933 batadv_hardif_put(hard_iface);
934
935 if (ret == NETDEV_TX_BUSY)
936 break;
937 }
938 rcu_read_unlock();
939
940 batadv_hardif_put(hard_iface: primary_if);
941 return ret;
942}
943
944/**
945 * batadv_forw_bcast_packet() - forward and queue a broadcast packet
946 * @bat_priv: the bat priv with all the mesh interface information
947 * @skb: broadcast packet to add
948 * @delay: number of jiffies to wait before sending
949 * @own_packet: true if it is a self-generated broadcast packet
950 *
951 * Transmits a broadcast packet either immediately or if a delay is given
952 * after that. Furthermore, queues additional retransmissions on wireless
953 * interfaces.
954 *
955 * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
956 */
957int batadv_forw_bcast_packet(struct batadv_priv *bat_priv,
958 struct sk_buff *skb,
959 unsigned long delay,
960 bool own_packet)
961{
962 return __batadv_forw_bcast_packet(bat_priv, skb, delay, own_packet);
963}
964
965/**
966 * batadv_send_bcast_packet() - send and queue a broadcast packet
967 * @bat_priv: the bat priv with all the mesh interface information
968 * @skb: broadcast packet to add
969 * @delay: number of jiffies to wait before sending
970 * @own_packet: true if it is a self-generated broadcast packet
971 *
972 * Transmits a broadcast packet either immediately or if a delay is given
973 * after that. Furthermore, queues additional retransmissions on wireless
974 * interfaces.
975 *
976 * Consumes the provided skb.
977 */
978void batadv_send_bcast_packet(struct batadv_priv *bat_priv,
979 struct sk_buff *skb,
980 unsigned long delay,
981 bool own_packet)
982{
983 __batadv_forw_bcast_packet(bat_priv, skb, delay, own_packet);
984 consume_skb(skb);
985}
986
987/**
988 * batadv_forw_packet_bcasts_left() - check if a retransmission is necessary
989 * @forw_packet: the forwarding packet to check
990 *
991 * Checks whether a given packet has any (re)transmissions left on the provided
992 * interface.
993 *
994 * hard_iface may be NULL: In that case the number of transmissions this skb had
995 * so far is compared with the maximum amount of retransmissions independent of
996 * any interface instead.
997 *
998 * Return: True if (re)transmissions are left, false otherwise.
999 */
1000static bool
1001batadv_forw_packet_bcasts_left(struct batadv_forw_packet *forw_packet)
1002{
1003 return BATADV_SKB_CB(forw_packet->skb)->num_bcasts;
1004}
1005
1006/**
1007 * batadv_forw_packet_bcasts_dec() - decrement retransmission counter of a
1008 * packet
1009 * @forw_packet: the packet to decrease the counter for
1010 */
1011static void
1012batadv_forw_packet_bcasts_dec(struct batadv_forw_packet *forw_packet)
1013{
1014 BATADV_SKB_CB(forw_packet->skb)->num_bcasts--;
1015}
1016
1017/**
1018 * batadv_forw_packet_is_rebroadcast() - check packet for previous transmissions
1019 * @forw_packet: the packet to check
1020 *
1021 * Return: True if this packet was transmitted before, false otherwise.
1022 */
1023bool batadv_forw_packet_is_rebroadcast(struct batadv_forw_packet *forw_packet)
1024{
1025 unsigned char num_bcasts = BATADV_SKB_CB(forw_packet->skb)->num_bcasts;
1026
1027 return num_bcasts != forw_packet->if_outgoing->num_bcasts;
1028}
1029
1030/**
1031 * batadv_send_outstanding_bcast_packet() - transmit a queued broadcast packet
1032 * @work: work queue item
1033 *
1034 * Transmits a queued broadcast packet and if necessary reschedules it.
1035 */
1036static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
1037{
1038 unsigned long send_time = jiffies + msecs_to_jiffies(m: 5);
1039 struct batadv_forw_packet *forw_packet;
1040 struct delayed_work *delayed_work;
1041 struct batadv_priv *bat_priv;
1042 struct sk_buff *skb1;
1043 bool dropped = false;
1044
1045 delayed_work = to_delayed_work(work);
1046 forw_packet = container_of(delayed_work, struct batadv_forw_packet,
1047 delayed_work);
1048 bat_priv = netdev_priv(dev: forw_packet->if_incoming->mesh_iface);
1049
1050 if (atomic_read(v: &bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
1051 dropped = true;
1052 goto out;
1053 }
1054
1055 if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet)) {
1056 dropped = true;
1057 goto out;
1058 }
1059
1060 /* send a copy of the saved skb */
1061 skb1 = skb_clone(skb: forw_packet->skb, GFP_ATOMIC);
1062 if (!skb1)
1063 goto out;
1064
1065 batadv_send_broadcast_skb(skb: skb1, hard_iface: forw_packet->if_outgoing);
1066 batadv_forw_packet_bcasts_dec(forw_packet);
1067
1068 if (batadv_forw_packet_bcasts_left(forw_packet)) {
1069 batadv_forw_packet_bcast_queue(bat_priv, forw_packet,
1070 send_time);
1071 return;
1072 }
1073
1074out:
1075 /* do we get something for free()? */
1076 if (batadv_forw_packet_steal(forw_packet,
1077 lock: &bat_priv->forw_bcast_list_lock))
1078 batadv_forw_packet_free(forw_packet, dropped);
1079}
1080
1081/**
1082 * batadv_purge_outstanding_packets() - stop/purge scheduled bcast/OGMv1 packets
1083 * @bat_priv: the bat priv with all the mesh interface information
1084 * @hard_iface: the hard interface to cancel and purge bcast/ogm packets on
1085 *
1086 * This method cancels and purges any broadcast and OGMv1 packet on the given
1087 * hard_iface. If hard_iface is NULL, broadcast and OGMv1 packets on all hard
1088 * interfaces will be canceled and purged.
1089 *
1090 * This function might sleep.
1091 */
1092void
1093batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
1094 const struct batadv_hard_iface *hard_iface)
1095{
1096 struct hlist_head head = HLIST_HEAD_INIT;
1097
1098 if (hard_iface)
1099 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
1100 "%s(): %s\n",
1101 __func__, hard_iface->net_dev->name);
1102 else
1103 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
1104 "%s()\n", __func__);
1105
1106 /* claim bcast list for free() */
1107 spin_lock_bh(lock: &bat_priv->forw_bcast_list_lock);
1108 batadv_forw_packet_list_steal(forw_list: &bat_priv->forw_bcast_list, cleanup_list: &head,
1109 hard_iface);
1110 spin_unlock_bh(lock: &bat_priv->forw_bcast_list_lock);
1111
1112 /* claim batman packet list for free() */
1113 spin_lock_bh(lock: &bat_priv->forw_bat_list_lock);
1114 batadv_forw_packet_list_steal(forw_list: &bat_priv->forw_bat_list, cleanup_list: &head,
1115 hard_iface);
1116 spin_unlock_bh(lock: &bat_priv->forw_bat_list_lock);
1117
1118 /* then cancel or wait for packet workers to finish and free */
1119 batadv_forw_packet_list_free(head: &head);
1120}
1121

source code of linux/net/batman-adv/send.c