Merge tag 'pinctrl-v5.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...
[linux-2.6-microblaze.git] / net / batman-adv / send.c
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/errno.h>
14 #include <linux/etherdevice.h>
15 #include <linux/gfp.h>
16 #include <linux/if.h>
17 #include <linux/if_ether.h>
18 #include <linux/jiffies.h>
19 #include <linux/kernel.h>
20 #include <linux/kref.h>
21 #include <linux/list.h>
22 #include <linux/netdevice.h>
23 #include <linux/printk.h>
24 #include <linux/rculist.h>
25 #include <linux/rcupdate.h>
26 #include <linux/skbuff.h>
27 #include <linux/slab.h>
28 #include <linux/spinlock.h>
29 #include <linux/stddef.h>
30 #include <linux/workqueue.h>
31
32 #include "distributed-arp-table.h"
33 #include "fragmentation.h"
34 #include "gateway_client.h"
35 #include "hard-interface.h"
36 #include "log.h"
37 #include "network-coding.h"
38 #include "originator.h"
39 #include "routing.h"
40 #include "soft-interface.h"
41 #include "translation-table.h"
42
43 static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
44
45 /**
46  * batadv_send_skb_packet() - send an already prepared packet
47  * @skb: the packet to send
48  * @hard_iface: the interface to use to send the broadcast packet
49  * @dst_addr: the payload destination
50  *
51  * Send out an already prepared packet to the given neighbor or broadcast it
52  * using the specified interface. Either hard_iface or neigh_node must be not
53  * NULL.
54  * If neigh_node is NULL, then the packet is broadcasted using hard_iface,
55  * otherwise it is sent as unicast to the given neighbor.
56  *
57  * Regardless of the return value, the skb is consumed.
58  *
59  * Return: A negative errno code is returned on a failure. A success does not
60  * guarantee the frame will be transmitted as it may be dropped due
61  * to congestion or traffic shaping.
62  */
63 int batadv_send_skb_packet(struct sk_buff *skb,
64                            struct batadv_hard_iface *hard_iface,
65                            const u8 *dst_addr)
66 {
67         struct batadv_priv *bat_priv;
68         struct ethhdr *ethhdr;
69         int ret;
70
71         bat_priv = netdev_priv(hard_iface->soft_iface);
72
73         if (hard_iface->if_status != BATADV_IF_ACTIVE)
74                 goto send_skb_err;
75
76         if (unlikely(!hard_iface->net_dev))
77                 goto send_skb_err;
78
79         if (!(hard_iface->net_dev->flags & IFF_UP)) {
80                 pr_warn("Interface %s is not up - can't send packet via that interface!\n",
81                         hard_iface->net_dev->name);
82                 goto send_skb_err;
83         }
84
85         /* push to the ethernet header. */
86         if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
87                 goto send_skb_err;
88
89         skb_reset_mac_header(skb);
90
91         ethhdr = eth_hdr(skb);
92         ether_addr_copy(ethhdr->h_source, hard_iface->net_dev->dev_addr);
93         ether_addr_copy(ethhdr->h_dest, dst_addr);
94         ethhdr->h_proto = htons(ETH_P_BATMAN);
95
96         skb_set_network_header(skb, ETH_HLEN);
97         skb->protocol = htons(ETH_P_BATMAN);
98
99         skb->dev = hard_iface->net_dev;
100
101         /* Save a clone of the skb to use when decoding coded packets */
102         batadv_nc_skb_store_for_decoding(bat_priv, skb);
103
104         /* dev_queue_xmit() returns a negative result on error.  However on
105          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
106          * (which is > 0). This will not be treated as an error.
107          */
108         ret = dev_queue_xmit(skb);
109         return net_xmit_eval(ret);
110 send_skb_err:
111         kfree_skb(skb);
112         return NET_XMIT_DROP;
113 }
114
115 /**
116  * batadv_send_broadcast_skb() - Send broadcast packet via hard interface
117  * @skb: packet to be transmitted (with batadv header and no outer eth header)
118  * @hard_iface: outgoing interface
119  *
120  * Return: A negative errno code is returned on a failure. A success does not
121  * guarantee the frame will be transmitted as it may be dropped due
122  * to congestion or traffic shaping.
123  */
124 int batadv_send_broadcast_skb(struct sk_buff *skb,
125                               struct batadv_hard_iface *hard_iface)
126 {
127         return batadv_send_skb_packet(skb, hard_iface, batadv_broadcast_addr);
128 }
129
130 /**
131  * batadv_send_unicast_skb() - Send unicast packet to neighbor
132  * @skb: packet to be transmitted (with batadv header and no outer eth header)
133  * @neigh: neighbor which is used as next hop to destination
134  *
135  * Return: A negative errno code is returned on a failure. A success does not
136  * guarantee the frame will be transmitted as it may be dropped due
137  * to congestion or traffic shaping.
138  */
139 int batadv_send_unicast_skb(struct sk_buff *skb,
140                             struct batadv_neigh_node *neigh)
141 {
142 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
143         struct batadv_hardif_neigh_node *hardif_neigh;
144 #endif
145         int ret;
146
147         ret = batadv_send_skb_packet(skb, neigh->if_incoming, neigh->addr);
148
149 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
150         hardif_neigh = batadv_hardif_neigh_get(neigh->if_incoming, neigh->addr);
151
152         if (hardif_neigh && ret != NET_XMIT_DROP)
153                 hardif_neigh->bat_v.last_unicast_tx = jiffies;
154
155         batadv_hardif_neigh_put(hardif_neigh);
156 #endif
157
158         return ret;
159 }
160
161 /**
162  * batadv_send_skb_to_orig() - Lookup next-hop and transmit skb.
163  * @skb: Packet to be transmitted.
164  * @orig_node: Final destination of the packet.
165  * @recv_if: Interface used when receiving the packet (can be NULL).
166  *
167  * Looks up the best next-hop towards the passed originator and passes the
168  * skb on for preparation of MAC header. If the packet originated from this
169  * host, NULL can be passed as recv_if and no interface alternating is
170  * attempted.
171  *
172  * Return: negative errno code on a failure, -EINPROGRESS if the skb is
173  * buffered for later transmit or the NET_XMIT status returned by the
174  * lower routine if the packet has been passed down.
175  */
176 int batadv_send_skb_to_orig(struct sk_buff *skb,
177                             struct batadv_orig_node *orig_node,
178                             struct batadv_hard_iface *recv_if)
179 {
180         struct batadv_priv *bat_priv = orig_node->bat_priv;
181         struct batadv_neigh_node *neigh_node;
182         int ret;
183
184         /* batadv_find_router() increases neigh_nodes refcount if found. */
185         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
186         if (!neigh_node) {
187                 ret = -EINVAL;
188                 goto free_skb;
189         }
190
191         /* Check if the skb is too large to send in one piece and fragment
192          * it if needed.
193          */
194         if (atomic_read(&bat_priv->fragmentation) &&
195             skb->len > neigh_node->if_incoming->net_dev->mtu) {
196                 /* Fragment and send packet. */
197                 ret = batadv_frag_send_packet(skb, orig_node, neigh_node);
198                 /* skb was consumed */
199                 skb = NULL;
200
201                 goto put_neigh_node;
202         }
203
204         /* try to network code the packet, if it is received on an interface
205          * (i.e. being forwarded). If the packet originates from this node or if
206          * network coding fails, then send the packet as usual.
207          */
208         if (recv_if && batadv_nc_skb_forward(skb, neigh_node))
209                 ret = -EINPROGRESS;
210         else
211                 ret = batadv_send_unicast_skb(skb, neigh_node);
212
213         /* skb was consumed */
214         skb = NULL;
215
216 put_neigh_node:
217         batadv_neigh_node_put(neigh_node);
218 free_skb:
219         kfree_skb(skb);
220
221         return ret;
222 }
223
224 /**
225  * batadv_send_skb_push_fill_unicast() - extend the buffer and initialize the
226  *  common fields for unicast packets
227  * @skb: the skb carrying the unicast header to initialize
228  * @hdr_size: amount of bytes to push at the beginning of the skb
229  * @orig_node: the destination node
230  *
231  * Return: false if the buffer extension was not possible or true otherwise.
232  */
233 static bool
234 batadv_send_skb_push_fill_unicast(struct sk_buff *skb, int hdr_size,
235                                   struct batadv_orig_node *orig_node)
236 {
237         struct batadv_unicast_packet *unicast_packet;
238         u8 ttvn = (u8)atomic_read(&orig_node->last_ttvn);
239
240         if (batadv_skb_head_push(skb, hdr_size) < 0)
241                 return false;
242
243         unicast_packet = (struct batadv_unicast_packet *)skb->data;
244         unicast_packet->version = BATADV_COMPAT_VERSION;
245         /* batman packet type: unicast */
246         unicast_packet->packet_type = BATADV_UNICAST;
247         /* set unicast ttl */
248         unicast_packet->ttl = BATADV_TTL;
249         /* copy the destination for faster routing */
250         ether_addr_copy(unicast_packet->dest, orig_node->orig);
251         /* set the destination tt version number */
252         unicast_packet->ttvn = ttvn;
253
254         return true;
255 }
256
257 /**
258  * batadv_send_skb_prepare_unicast() - encapsulate an skb with a unicast header
259  * @skb: the skb containing the payload to encapsulate
260  * @orig_node: the destination node
261  *
262  * Return: false if the payload could not be encapsulated or true otherwise.
263  */
264 static bool batadv_send_skb_prepare_unicast(struct sk_buff *skb,
265                                             struct batadv_orig_node *orig_node)
266 {
267         size_t uni_size = sizeof(struct batadv_unicast_packet);
268
269         return batadv_send_skb_push_fill_unicast(skb, uni_size, orig_node);
270 }
271
272 /**
273  * batadv_send_skb_prepare_unicast_4addr() - encapsulate an skb with a
274  *  unicast 4addr header
275  * @bat_priv: the bat priv with all the soft interface information
276  * @skb: the skb containing the payload to encapsulate
277  * @orig: the destination node
278  * @packet_subtype: the unicast 4addr packet subtype to use
279  *
280  * Return: false if the payload could not be encapsulated or true otherwise.
281  */
282 bool batadv_send_skb_prepare_unicast_4addr(struct batadv_priv *bat_priv,
283                                            struct sk_buff *skb,
284                                            struct batadv_orig_node *orig,
285                                            int packet_subtype)
286 {
287         struct batadv_hard_iface *primary_if;
288         struct batadv_unicast_4addr_packet *uc_4addr_packet;
289         bool ret = false;
290
291         primary_if = batadv_primary_if_get_selected(bat_priv);
292         if (!primary_if)
293                 goto out;
294
295         /* Pull the header space and fill the unicast_packet substructure.
296          * We can do that because the first member of the uc_4addr_packet
297          * is of type struct unicast_packet
298          */
299         if (!batadv_send_skb_push_fill_unicast(skb, sizeof(*uc_4addr_packet),
300                                                orig))
301                 goto out;
302
303         uc_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
304         uc_4addr_packet->u.packet_type = BATADV_UNICAST_4ADDR;
305         ether_addr_copy(uc_4addr_packet->src, primary_if->net_dev->dev_addr);
306         uc_4addr_packet->subtype = packet_subtype;
307         uc_4addr_packet->reserved = 0;
308
309         ret = true;
310 out:
311         batadv_hardif_put(primary_if);
312         return ret;
313 }
314
315 /**
316  * batadv_send_skb_unicast() - encapsulate and send an skb via unicast
317  * @bat_priv: the bat priv with all the soft interface information
318  * @skb: payload to send
319  * @packet_type: the batman unicast packet type to use
320  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
321  *  4addr packets)
322  * @orig_node: the originator to send the packet to
323  * @vid: the vid to be used to search the translation table
324  *
325  * Wrap the given skb into a batman-adv unicast or unicast-4addr header
326  * depending on whether BATADV_UNICAST or BATADV_UNICAST_4ADDR was supplied
327  * as packet_type. Then send this frame to the given orig_node.
328  *
329  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
330  */
331 int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
332                             struct sk_buff *skb, int packet_type,
333                             int packet_subtype,
334                             struct batadv_orig_node *orig_node,
335                             unsigned short vid)
336 {
337         struct batadv_unicast_packet *unicast_packet;
338         struct ethhdr *ethhdr;
339         int ret = NET_XMIT_DROP;
340
341         if (!orig_node)
342                 goto out;
343
344         switch (packet_type) {
345         case BATADV_UNICAST:
346                 if (!batadv_send_skb_prepare_unicast(skb, orig_node))
347                         goto out;
348                 break;
349         case BATADV_UNICAST_4ADDR:
350                 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
351                                                            orig_node,
352                                                            packet_subtype))
353                         goto out;
354                 break;
355         default:
356                 /* this function supports UNICAST and UNICAST_4ADDR only. It
357                  * should never be invoked with any other packet type
358                  */
359                 goto out;
360         }
361
362         /* skb->data might have been reallocated by
363          * batadv_send_skb_prepare_unicast{,_4addr}()
364          */
365         ethhdr = eth_hdr(skb);
366         unicast_packet = (struct batadv_unicast_packet *)skb->data;
367
368         /* inform the destination node that we are still missing a correct route
369          * for this client. The destination will receive this packet and will
370          * try to reroute it because the ttvn contained in the header is less
371          * than the current one
372          */
373         if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest, vid))
374                 unicast_packet->ttvn = unicast_packet->ttvn - 1;
375
376         ret = batadv_send_skb_to_orig(skb, orig_node, NULL);
377          /* skb was consumed */
378         skb = NULL;
379
380 out:
381         kfree_skb(skb);
382         return ret;
383 }
384
385 /**
386  * batadv_send_skb_via_tt_generic() - send an skb via TT lookup
387  * @bat_priv: the bat priv with all the soft interface information
388  * @skb: payload to send
389  * @packet_type: the batman unicast packet type to use
390  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
391  *  4addr packets)
392  * @dst_hint: can be used to override the destination contained in the skb
393  * @vid: the vid to be used to search the translation table
394  *
395  * Look up the recipient node for the destination address in the ethernet
396  * header via the translation table. Wrap the given skb into a batman-adv
397  * unicast or unicast-4addr header depending on whether BATADV_UNICAST or
398  * BATADV_UNICAST_4ADDR was supplied as packet_type. Then send this frame
399  * to the according destination node.
400  *
401  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
402  */
403 int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
404                                    struct sk_buff *skb, int packet_type,
405                                    int packet_subtype, u8 *dst_hint,
406                                    unsigned short vid)
407 {
408         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
409         struct batadv_orig_node *orig_node;
410         u8 *src, *dst;
411         int ret;
412
413         src = ethhdr->h_source;
414         dst = ethhdr->h_dest;
415
416         /* if we got an hint! let's send the packet to this client (if any) */
417         if (dst_hint) {
418                 src = NULL;
419                 dst = dst_hint;
420         }
421         orig_node = batadv_transtable_search(bat_priv, src, dst, vid);
422
423         ret = batadv_send_skb_unicast(bat_priv, skb, packet_type,
424                                       packet_subtype, orig_node, vid);
425
426         batadv_orig_node_put(orig_node);
427
428         return ret;
429 }
430
431 /**
432  * batadv_send_skb_via_gw() - send an skb via gateway lookup
433  * @bat_priv: the bat priv with all the soft interface information
434  * @skb: payload to send
435  * @vid: the vid to be used to search the translation table
436  *
437  * Look up the currently selected gateway. Wrap the given skb into a batman-adv
438  * unicast header and send this frame to this gateway node.
439  *
440  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
441  */
442 int batadv_send_skb_via_gw(struct batadv_priv *bat_priv, struct sk_buff *skb,
443                            unsigned short vid)
444 {
445         struct batadv_orig_node *orig_node;
446         int ret;
447
448         orig_node = batadv_gw_get_selected_orig(bat_priv);
449         ret = batadv_send_skb_unicast(bat_priv, skb, BATADV_UNICAST_4ADDR,
450                                       BATADV_P_DATA, orig_node, vid);
451
452         batadv_orig_node_put(orig_node);
453
454         return ret;
455 }
456
457 /**
458  * batadv_forw_packet_free() - free a forwarding packet
459  * @forw_packet: The packet to free
460  * @dropped: whether the packet is freed because is dropped
461  *
462  * This frees a forwarding packet and releases any resources it might
463  * have claimed.
464  */
465 void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet,
466                              bool dropped)
467 {
468         if (dropped)
469                 kfree_skb(forw_packet->skb);
470         else
471                 consume_skb(forw_packet->skb);
472
473         batadv_hardif_put(forw_packet->if_incoming);
474         batadv_hardif_put(forw_packet->if_outgoing);
475         if (forw_packet->queue_left)
476                 atomic_inc(forw_packet->queue_left);
477         kfree(forw_packet);
478 }
479
480 /**
481  * batadv_forw_packet_alloc() - allocate a forwarding packet
482  * @if_incoming: The (optional) if_incoming to be grabbed
483  * @if_outgoing: The (optional) if_outgoing to be grabbed
484  * @queue_left: The (optional) queue counter to decrease
485  * @bat_priv: The bat_priv for the mesh of this forw_packet
486  * @skb: The raw packet this forwarding packet shall contain
487  *
488  * Allocates a forwarding packet and tries to get a reference to the
489  * (optional) if_incoming, if_outgoing and queue_left. If queue_left
490  * is NULL then bat_priv is optional, too.
491  *
492  * Return: An allocated forwarding packet on success, NULL otherwise.
493  */
494 struct batadv_forw_packet *
495 batadv_forw_packet_alloc(struct batadv_hard_iface *if_incoming,
496                          struct batadv_hard_iface *if_outgoing,
497                          atomic_t *queue_left,
498                          struct batadv_priv *bat_priv,
499                          struct sk_buff *skb)
500 {
501         struct batadv_forw_packet *forw_packet;
502         const char *qname;
503
504         if (queue_left && !batadv_atomic_dec_not_zero(queue_left)) {
505                 qname = "unknown";
506
507                 if (queue_left == &bat_priv->bcast_queue_left)
508                         qname = "bcast";
509
510                 if (queue_left == &bat_priv->batman_queue_left)
511                         qname = "batman";
512
513                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
514                            "%s queue is full\n", qname);
515
516                 return NULL;
517         }
518
519         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
520         if (!forw_packet)
521                 goto err;
522
523         if (if_incoming)
524                 kref_get(&if_incoming->refcount);
525
526         if (if_outgoing)
527                 kref_get(&if_outgoing->refcount);
528
529         INIT_HLIST_NODE(&forw_packet->list);
530         INIT_HLIST_NODE(&forw_packet->cleanup_list);
531         forw_packet->skb = skb;
532         forw_packet->queue_left = queue_left;
533         forw_packet->if_incoming = if_incoming;
534         forw_packet->if_outgoing = if_outgoing;
535         forw_packet->num_packets = 0;
536
537         return forw_packet;
538
539 err:
540         if (queue_left)
541                 atomic_inc(queue_left);
542
543         return NULL;
544 }
545
546 /**
547  * batadv_forw_packet_was_stolen() - check whether someone stole this packet
548  * @forw_packet: the forwarding packet to check
549  *
550  * This function checks whether the given forwarding packet was claimed by
551  * someone else for free().
552  *
553  * Return: True if someone stole it, false otherwise.
554  */
555 static bool
556 batadv_forw_packet_was_stolen(struct batadv_forw_packet *forw_packet)
557 {
558         return !hlist_unhashed(&forw_packet->cleanup_list);
559 }
560
561 /**
562  * batadv_forw_packet_steal() - claim a forw_packet for free()
563  * @forw_packet: the forwarding packet to steal
564  * @lock: a key to the store to steal from (e.g. forw_{bat,bcast}_list_lock)
565  *
566  * This function tries to steal a specific forw_packet from global
567  * visibility for the purpose of getting it for free(). That means
568  * the caller is *not* allowed to requeue it afterwards.
569  *
570  * Return: True if stealing was successful. False if someone else stole it
571  * before us.
572  */
573 bool batadv_forw_packet_steal(struct batadv_forw_packet *forw_packet,
574                               spinlock_t *lock)
575 {
576         /* did purging routine steal it earlier? */
577         spin_lock_bh(lock);
578         if (batadv_forw_packet_was_stolen(forw_packet)) {
579                 spin_unlock_bh(lock);
580                 return false;
581         }
582
583         hlist_del_init(&forw_packet->list);
584
585         /* Just to spot misuse of this function */
586         hlist_add_fake(&forw_packet->cleanup_list);
587
588         spin_unlock_bh(lock);
589         return true;
590 }
591
592 /**
593  * batadv_forw_packet_list_steal() - claim a list of forward packets for free()
594  * @forw_list: the to be stolen forward packets
595  * @cleanup_list: a backup pointer, to be able to dispose the packet later
596  * @hard_iface: the interface to steal forward packets from
597  *
598  * This function claims responsibility to free any forw_packet queued on the
599  * given hard_iface. If hard_iface is NULL forwarding packets on all hard
600  * interfaces will be claimed.
601  *
602  * The packets are being moved from the forw_list to the cleanup_list. This
603  * makes it possible for already running threads to notice the claim.
604  */
605 static void
606 batadv_forw_packet_list_steal(struct hlist_head *forw_list,
607                               struct hlist_head *cleanup_list,
608                               const struct batadv_hard_iface *hard_iface)
609 {
610         struct batadv_forw_packet *forw_packet;
611         struct hlist_node *safe_tmp_node;
612
613         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
614                                   forw_list, list) {
615                 /* if purge_outstanding_packets() was called with an argument
616                  * we delete only packets belonging to the given interface
617                  */
618                 if (hard_iface &&
619                     forw_packet->if_incoming != hard_iface &&
620                     forw_packet->if_outgoing != hard_iface)
621                         continue;
622
623                 hlist_del(&forw_packet->list);
624                 hlist_add_head(&forw_packet->cleanup_list, cleanup_list);
625         }
626 }
627
628 /**
629  * batadv_forw_packet_list_free() - free a list of forward packets
630  * @head: a list of to be freed forw_packets
631  *
632  * This function cancels the scheduling of any packet in the provided list,
633  * waits for any possibly running packet forwarding thread to finish and
634  * finally, safely frees this forward packet.
635  *
636  * This function might sleep.
637  */
638 static void batadv_forw_packet_list_free(struct hlist_head *head)
639 {
640         struct batadv_forw_packet *forw_packet;
641         struct hlist_node *safe_tmp_node;
642
643         hlist_for_each_entry_safe(forw_packet, safe_tmp_node, head,
644                                   cleanup_list) {
645                 cancel_delayed_work_sync(&forw_packet->delayed_work);
646
647                 hlist_del(&forw_packet->cleanup_list);
648                 batadv_forw_packet_free(forw_packet, true);
649         }
650 }
651
652 /**
653  * batadv_forw_packet_queue() - try to queue a forwarding packet
654  * @forw_packet: the forwarding packet to queue
655  * @lock: a key to the store (e.g. forw_{bat,bcast}_list_lock)
656  * @head: the shelve to queue it on (e.g. forw_{bat,bcast}_list)
657  * @send_time: timestamp (jiffies) when the packet is to be sent
658  *
659  * This function tries to (re)queue a forwarding packet. Requeuing
660  * is prevented if the according interface is shutting down
661  * (e.g. if batadv_forw_packet_list_steal() was called for this
662  * packet earlier).
663  *
664  * Calling batadv_forw_packet_queue() after a call to
665  * batadv_forw_packet_steal() is forbidden!
666  *
667  * Caller needs to ensure that forw_packet->delayed_work was initialized.
668  */
669 static void batadv_forw_packet_queue(struct batadv_forw_packet *forw_packet,
670                                      spinlock_t *lock, struct hlist_head *head,
671                                      unsigned long send_time)
672 {
673         spin_lock_bh(lock);
674
675         /* did purging routine steal it from us? */
676         if (batadv_forw_packet_was_stolen(forw_packet)) {
677                 /* If you got it for free() without trouble, then
678                  * don't get back into the queue after stealing...
679                  */
680                 WARN_ONCE(hlist_fake(&forw_packet->cleanup_list),
681                           "Requeuing after batadv_forw_packet_steal() not allowed!\n");
682
683                 spin_unlock_bh(lock);
684                 return;
685         }
686
687         hlist_del_init(&forw_packet->list);
688         hlist_add_head(&forw_packet->list, head);
689
690         queue_delayed_work(batadv_event_workqueue,
691                            &forw_packet->delayed_work,
692                            send_time - jiffies);
693         spin_unlock_bh(lock);
694 }
695
696 /**
697  * batadv_forw_packet_bcast_queue() - try to queue a broadcast packet
698  * @bat_priv: the bat priv with all the soft interface information
699  * @forw_packet: the forwarding packet to queue
700  * @send_time: timestamp (jiffies) when the packet is to be sent
701  *
702  * This function tries to (re)queue a broadcast packet.
703  *
704  * Caller needs to ensure that forw_packet->delayed_work was initialized.
705  */
706 static void
707 batadv_forw_packet_bcast_queue(struct batadv_priv *bat_priv,
708                                struct batadv_forw_packet *forw_packet,
709                                unsigned long send_time)
710 {
711         batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bcast_list_lock,
712                                  &bat_priv->forw_bcast_list, send_time);
713 }
714
715 /**
716  * batadv_forw_packet_ogmv1_queue() - try to queue an OGMv1 packet
717  * @bat_priv: the bat priv with all the soft interface information
718  * @forw_packet: the forwarding packet to queue
719  * @send_time: timestamp (jiffies) when the packet is to be sent
720  *
721  * This function tries to (re)queue an OGMv1 packet.
722  *
723  * Caller needs to ensure that forw_packet->delayed_work was initialized.
724  */
725 void batadv_forw_packet_ogmv1_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_bat_list_lock,
730                                  &bat_priv->forw_bat_list, send_time);
731 }
732
733 /**
734  * batadv_forw_bcast_packet_to_list() - queue broadcast packet for transmissions
735  * @bat_priv: the bat priv with all the soft interface information
736  * @skb: broadcast packet to add
737  * @delay: number of jiffies to wait before sending
738  * @own_packet: true if it is a self-generated broadcast packet
739  * @if_in: the interface where the packet was received on
740  * @if_out: the outgoing interface to queue on
741  *
742  * Adds a broadcast packet to the queue and sets up timers. Broadcast packets
743  * are sent multiple times to increase probability for being received.
744  *
745  * This call clones the given skb, hence the caller needs to take into
746  * account that the data segment of the original skb might not be
747  * modifiable anymore.
748  *
749  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
750  */
751 static int batadv_forw_bcast_packet_to_list(struct batadv_priv *bat_priv,
752                                             struct sk_buff *skb,
753                                             unsigned long delay,
754                                             bool own_packet,
755                                             struct batadv_hard_iface *if_in,
756                                             struct batadv_hard_iface *if_out)
757 {
758         struct batadv_forw_packet *forw_packet;
759         unsigned long send_time = jiffies;
760         struct sk_buff *newskb;
761
762         newskb = skb_clone(skb, GFP_ATOMIC);
763         if (!newskb)
764                 goto err;
765
766         forw_packet = batadv_forw_packet_alloc(if_in, if_out,
767                                                &bat_priv->bcast_queue_left,
768                                                bat_priv, newskb);
769         if (!forw_packet)
770                 goto err_packet_free;
771
772         forw_packet->own = own_packet;
773
774         INIT_DELAYED_WORK(&forw_packet->delayed_work,
775                           batadv_send_outstanding_bcast_packet);
776
777         send_time += delay ? delay : msecs_to_jiffies(5);
778
779         batadv_forw_packet_bcast_queue(bat_priv, forw_packet, send_time);
780         return NETDEV_TX_OK;
781
782 err_packet_free:
783         kfree_skb(newskb);
784 err:
785         return NETDEV_TX_BUSY;
786 }
787
788 /**
789  * batadv_forw_bcast_packet_if() - forward and queue a broadcast packet
790  * @bat_priv: the bat priv with all the soft interface information
791  * @skb: broadcast packet to add
792  * @delay: number of jiffies to wait before sending
793  * @own_packet: true if it is a self-generated broadcast packet
794  * @if_in: the interface where the packet was received on
795  * @if_out: the outgoing interface to forward to
796  *
797  * Transmits a broadcast packet on the specified interface either immediately
798  * or if a delay is given after that. Furthermore, queues additional
799  * retransmissions if this interface is a wireless one.
800  *
801  * This call clones the given skb, hence the caller needs to take into
802  * account that the data segment of the original skb might not be
803  * modifiable anymore.
804  *
805  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
806  */
807 static int batadv_forw_bcast_packet_if(struct batadv_priv *bat_priv,
808                                        struct sk_buff *skb,
809                                        unsigned long delay,
810                                        bool own_packet,
811                                        struct batadv_hard_iface *if_in,
812                                        struct batadv_hard_iface *if_out)
813 {
814         unsigned int num_bcasts = if_out->num_bcasts;
815         struct sk_buff *newskb;
816         int ret = NETDEV_TX_OK;
817
818         if (!delay) {
819                 newskb = skb_clone(skb, GFP_ATOMIC);
820                 if (!newskb)
821                         return NETDEV_TX_BUSY;
822
823                 batadv_send_broadcast_skb(newskb, if_out);
824                 num_bcasts--;
825         }
826
827         /* delayed broadcast or rebroadcasts? */
828         if (num_bcasts >= 1) {
829                 BATADV_SKB_CB(skb)->num_bcasts = num_bcasts;
830
831                 ret = batadv_forw_bcast_packet_to_list(bat_priv, skb, delay,
832                                                        own_packet, if_in,
833                                                        if_out);
834         }
835
836         return ret;
837 }
838
839 /**
840  * batadv_send_no_broadcast() - check whether (re)broadcast is necessary
841  * @bat_priv: the bat priv with all the soft interface information
842  * @skb: broadcast packet to check
843  * @own_packet: true if it is a self-generated broadcast packet
844  * @if_out: the outgoing interface checked and considered for (re)broadcast
845  *
846  * Return: False if a packet needs to be (re)broadcasted on the given interface,
847  * true otherwise.
848  */
849 static bool batadv_send_no_broadcast(struct batadv_priv *bat_priv,
850                                      struct sk_buff *skb, bool own_packet,
851                                      struct batadv_hard_iface *if_out)
852 {
853         struct batadv_hardif_neigh_node *neigh_node = NULL;
854         struct batadv_bcast_packet *bcast_packet;
855         u8 *orig_neigh;
856         u8 *neigh_addr;
857         char *type;
858         int ret;
859
860         if (!own_packet) {
861                 neigh_addr = eth_hdr(skb)->h_source;
862                 neigh_node = batadv_hardif_neigh_get(if_out,
863                                                      neigh_addr);
864         }
865
866         bcast_packet = (struct batadv_bcast_packet *)skb->data;
867         orig_neigh = neigh_node ? neigh_node->orig : NULL;
868
869         ret = batadv_hardif_no_broadcast(if_out, bcast_packet->orig,
870                                          orig_neigh);
871
872         batadv_hardif_neigh_put(neigh_node);
873
874         /* ok, may broadcast */
875         if (!ret)
876                 return false;
877
878         /* no broadcast */
879         switch (ret) {
880         case BATADV_HARDIF_BCAST_NORECIPIENT:
881                 type = "no neighbor";
882                 break;
883         case BATADV_HARDIF_BCAST_DUPFWD:
884                 type = "single neighbor is source";
885                 break;
886         case BATADV_HARDIF_BCAST_DUPORIG:
887                 type = "single neighbor is originator";
888                 break;
889         default:
890                 type = "unknown";
891         }
892
893         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
894                    "BCAST packet from orig %pM on %s suppressed: %s\n",
895                    bcast_packet->orig,
896                    if_out->net_dev->name, type);
897
898         return true;
899 }
900
901 /**
902  * __batadv_forw_bcast_packet() - forward and queue a broadcast packet
903  * @bat_priv: the bat priv with all the soft interface information
904  * @skb: broadcast packet to add
905  * @delay: number of jiffies to wait before sending
906  * @own_packet: true if it is a self-generated broadcast packet
907  *
908  * Transmits a broadcast packet either immediately or if a delay is given
909  * after that. Furthermore, queues additional retransmissions on wireless
910  * interfaces.
911  *
912  * This call clones the given skb, hence the caller needs to take into
913  * account that the data segment of the given skb might not be
914  * modifiable anymore.
915  *
916  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
917  */
918 static int __batadv_forw_bcast_packet(struct batadv_priv *bat_priv,
919                                       struct sk_buff *skb,
920                                       unsigned long delay,
921                                       bool own_packet)
922 {
923         struct batadv_hard_iface *hard_iface;
924         struct batadv_hard_iface *primary_if;
925         int ret = NETDEV_TX_OK;
926
927         primary_if = batadv_primary_if_get_selected(bat_priv);
928         if (!primary_if)
929                 return NETDEV_TX_BUSY;
930
931         rcu_read_lock();
932         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
933                 if (hard_iface->soft_iface != bat_priv->soft_iface)
934                         continue;
935
936                 if (!kref_get_unless_zero(&hard_iface->refcount))
937                         continue;
938
939                 if (batadv_send_no_broadcast(bat_priv, skb, own_packet,
940                                              hard_iface)) {
941                         batadv_hardif_put(hard_iface);
942                         continue;
943                 }
944
945                 ret = batadv_forw_bcast_packet_if(bat_priv, skb, delay,
946                                                   own_packet, primary_if,
947                                                   hard_iface);
948                 batadv_hardif_put(hard_iface);
949
950                 if (ret == NETDEV_TX_BUSY)
951                         break;
952         }
953         rcu_read_unlock();
954
955         batadv_hardif_put(primary_if);
956         return ret;
957 }
958
959 /**
960  * batadv_forw_bcast_packet() - forward and queue a broadcast packet
961  * @bat_priv: the bat priv with all the soft interface information
962  * @skb: broadcast packet to add
963  * @delay: number of jiffies to wait before sending
964  * @own_packet: true if it is a self-generated broadcast packet
965  *
966  * Transmits a broadcast packet either immediately or if a delay is given
967  * after that. Furthermore, queues additional retransmissions on wireless
968  * interfaces.
969  *
970  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
971  */
972 int batadv_forw_bcast_packet(struct batadv_priv *bat_priv,
973                              struct sk_buff *skb,
974                              unsigned long delay,
975                              bool own_packet)
976 {
977         return __batadv_forw_bcast_packet(bat_priv, skb, delay, own_packet);
978 }
979
980 /**
981  * batadv_send_bcast_packet() - send and queue a broadcast packet
982  * @bat_priv: the bat priv with all the soft interface information
983  * @skb: broadcast packet to add
984  * @delay: number of jiffies to wait before sending
985  * @own_packet: true if it is a self-generated broadcast packet
986  *
987  * Transmits a broadcast packet either immediately or if a delay is given
988  * after that. Furthermore, queues additional retransmissions on wireless
989  * interfaces.
990  *
991  * Consumes the provided skb.
992  */
993 void batadv_send_bcast_packet(struct batadv_priv *bat_priv,
994                               struct sk_buff *skb,
995                               unsigned long delay,
996                               bool own_packet)
997 {
998         __batadv_forw_bcast_packet(bat_priv, skb, delay, own_packet);
999         consume_skb(skb);
1000 }
1001
1002 /**
1003  * batadv_forw_packet_bcasts_left() - check if a retransmission is necessary
1004  * @forw_packet: the forwarding packet to check
1005  *
1006  * Checks whether a given packet has any (re)transmissions left on the provided
1007  * interface.
1008  *
1009  * hard_iface may be NULL: In that case the number of transmissions this skb had
1010  * so far is compared with the maximum amount of retransmissions independent of
1011  * any interface instead.
1012  *
1013  * Return: True if (re)transmissions are left, false otherwise.
1014  */
1015 static bool
1016 batadv_forw_packet_bcasts_left(struct batadv_forw_packet *forw_packet)
1017 {
1018         return BATADV_SKB_CB(forw_packet->skb)->num_bcasts;
1019 }
1020
1021 /**
1022  * batadv_forw_packet_bcasts_dec() - decrement retransmission counter of a
1023  *  packet
1024  * @forw_packet: the packet to decrease the counter for
1025  */
1026 static void
1027 batadv_forw_packet_bcasts_dec(struct batadv_forw_packet *forw_packet)
1028 {
1029         BATADV_SKB_CB(forw_packet->skb)->num_bcasts--;
1030 }
1031
1032 /**
1033  * batadv_forw_packet_is_rebroadcast() - check packet for previous transmissions
1034  * @forw_packet: the packet to check
1035  *
1036  * Return: True if this packet was transmitted before, false otherwise.
1037  */
1038 bool batadv_forw_packet_is_rebroadcast(struct batadv_forw_packet *forw_packet)
1039 {
1040         unsigned char num_bcasts = BATADV_SKB_CB(forw_packet->skb)->num_bcasts;
1041
1042         return num_bcasts != forw_packet->if_outgoing->num_bcasts;
1043 }
1044
1045 /**
1046  * batadv_send_outstanding_bcast_packet() - transmit a queued broadcast packet
1047  * @work: work queue item
1048  *
1049  * Transmits a queued broadcast packet and if necessary reschedules it.
1050  */
1051 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
1052 {
1053         unsigned long send_time = jiffies + msecs_to_jiffies(5);
1054         struct batadv_forw_packet *forw_packet;
1055         struct delayed_work *delayed_work;
1056         struct batadv_priv *bat_priv;
1057         struct sk_buff *skb1;
1058         bool dropped = false;
1059
1060         delayed_work = to_delayed_work(work);
1061         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
1062                                    delayed_work);
1063         bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
1064
1065         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
1066                 dropped = true;
1067                 goto out;
1068         }
1069
1070         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet)) {
1071                 dropped = true;
1072                 goto out;
1073         }
1074
1075         /* send a copy of the saved skb */
1076         skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
1077         if (!skb1)
1078                 goto out;
1079
1080         batadv_send_broadcast_skb(skb1, forw_packet->if_outgoing);
1081         batadv_forw_packet_bcasts_dec(forw_packet);
1082
1083         if (batadv_forw_packet_bcasts_left(forw_packet)) {
1084                 batadv_forw_packet_bcast_queue(bat_priv, forw_packet,
1085                                                send_time);
1086                 return;
1087         }
1088
1089 out:
1090         /* do we get something for free()? */
1091         if (batadv_forw_packet_steal(forw_packet,
1092                                      &bat_priv->forw_bcast_list_lock))
1093                 batadv_forw_packet_free(forw_packet, dropped);
1094 }
1095
1096 /**
1097  * batadv_purge_outstanding_packets() - stop/purge scheduled bcast/OGMv1 packets
1098  * @bat_priv: the bat priv with all the soft interface information
1099  * @hard_iface: the hard interface to cancel and purge bcast/ogm packets on
1100  *
1101  * This method cancels and purges any broadcast and OGMv1 packet on the given
1102  * hard_iface. If hard_iface is NULL, broadcast and OGMv1 packets on all hard
1103  * interfaces will be canceled and purged.
1104  *
1105  * This function might sleep.
1106  */
1107 void
1108 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
1109                                  const struct batadv_hard_iface *hard_iface)
1110 {
1111         struct hlist_head head = HLIST_HEAD_INIT;
1112
1113         if (hard_iface)
1114                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
1115                            "%s(): %s\n",
1116                            __func__, hard_iface->net_dev->name);
1117         else
1118                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
1119                            "%s()\n", __func__);
1120
1121         /* claim bcast list for free() */
1122         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
1123         batadv_forw_packet_list_steal(&bat_priv->forw_bcast_list, &head,
1124                                       hard_iface);
1125         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
1126
1127         /* claim batman packet list for free() */
1128         spin_lock_bh(&bat_priv->forw_bat_list_lock);
1129         batadv_forw_packet_list_steal(&bat_priv->forw_bat_list, &head,
1130                                       hard_iface);
1131         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
1132
1133         /* then cancel or wait for packet workers to finish and free */
1134         batadv_forw_packet_list_free(&head);
1135 }