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TOMOYO Linux Cross Reference
Linux/net/batman-adv/send.c

Version: ~ [ linux-5.4 ] ~ [ linux-5.3.13 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.86 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.156 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.203 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.202 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.78 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /* Copyright (C) 2007-2017  B.A.T.M.A.N. contributors:
  2  *
  3  * Marek Lindner, Simon Wunderlich
  4  *
  5  * This program is free software; you can redistribute it and/or
  6  * modify it under the terms of version 2 of the GNU General Public
  7  * License as published by the Free Software Foundation.
  8  *
  9  * This program is distributed in the hope that it will be useful, but
 10  * WITHOUT ANY WARRANTY; without even the implied warranty of
 11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 12  * General Public License for more details.
 13  *
 14  * You should have received a copy of the GNU General Public License
 15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
 16  */
 17 
 18 #include "send.h"
 19 #include "main.h"
 20 
 21 #include <linux/atomic.h>
 22 #include <linux/bug.h>
 23 #include <linux/byteorder/generic.h>
 24 #include <linux/errno.h>
 25 #include <linux/etherdevice.h>
 26 #include <linux/fs.h>
 27 #include <linux/if.h>
 28 #include <linux/if_ether.h>
 29 #include <linux/jiffies.h>
 30 #include <linux/kernel.h>
 31 #include <linux/kref.h>
 32 #include <linux/list.h>
 33 #include <linux/netdevice.h>
 34 #include <linux/printk.h>
 35 #include <linux/rculist.h>
 36 #include <linux/rcupdate.h>
 37 #include <linux/skbuff.h>
 38 #include <linux/slab.h>
 39 #include <linux/spinlock.h>
 40 #include <linux/stddef.h>
 41 #include <linux/workqueue.h>
 42 
 43 #include "distributed-arp-table.h"
 44 #include "fragmentation.h"
 45 #include "gateway_client.h"
 46 #include "hard-interface.h"
 47 #include "log.h"
 48 #include "network-coding.h"
 49 #include "originator.h"
 50 #include "routing.h"
 51 #include "soft-interface.h"
 52 #include "translation-table.h"
 53 
 54 static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
 55 
 56 /**
 57  * batadv_send_skb_packet - send an already prepared packet
 58  * @skb: the packet to send
 59  * @hard_iface: the interface to use to send the broadcast packet
 60  * @dst_addr: the payload destination
 61  *
 62  * Send out an already prepared packet to the given neighbor or broadcast it
 63  * using the specified interface. Either hard_iface or neigh_node must be not
 64  * NULL.
 65  * If neigh_node is NULL, then the packet is broadcasted using hard_iface,
 66  * otherwise it is sent as unicast to the given neighbor.
 67  *
 68  * Regardless of the return value, the skb is consumed.
 69  *
 70  * Return: A negative errno code is returned on a failure. A success does not
 71  * guarantee the frame will be transmitted as it may be dropped due
 72  * to congestion or traffic shaping.
 73  */
 74 int batadv_send_skb_packet(struct sk_buff *skb,
 75                            struct batadv_hard_iface *hard_iface,
 76                            const u8 *dst_addr)
 77 {
 78         struct batadv_priv *bat_priv;
 79         struct ethhdr *ethhdr;
 80         int ret;
 81 
 82         bat_priv = netdev_priv(hard_iface->soft_iface);
 83 
 84         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 85                 goto send_skb_err;
 86 
 87         if (unlikely(!hard_iface->net_dev))
 88                 goto send_skb_err;
 89 
 90         if (!(hard_iface->net_dev->flags & IFF_UP)) {
 91                 pr_warn("Interface %s is not up - can't send packet via that interface!\n",
 92                         hard_iface->net_dev->name);
 93                 goto send_skb_err;
 94         }
 95 
 96         /* push to the ethernet header. */
 97         if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
 98                 goto send_skb_err;
 99 
100         skb_reset_mac_header(skb);
101 
102         ethhdr = eth_hdr(skb);
103         ether_addr_copy(ethhdr->h_source, hard_iface->net_dev->dev_addr);
104         ether_addr_copy(ethhdr->h_dest, dst_addr);
105         ethhdr->h_proto = htons(ETH_P_BATMAN);
106 
107         skb_set_network_header(skb, ETH_HLEN);
108         skb->protocol = htons(ETH_P_BATMAN);
109 
110         skb->dev = hard_iface->net_dev;
111 
112         /* Save a clone of the skb to use when decoding coded packets */
113         batadv_nc_skb_store_for_decoding(bat_priv, skb);
114 
115         /* dev_queue_xmit() returns a negative result on error.  However on
116          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
117          * (which is > 0). This will not be treated as an error.
118          */
119         ret = dev_queue_xmit(skb);
120         return net_xmit_eval(ret);
121 send_skb_err:
122         kfree_skb(skb);
123         return NET_XMIT_DROP;
124 }
125 
126 int batadv_send_broadcast_skb(struct sk_buff *skb,
127                               struct batadv_hard_iface *hard_iface)
128 {
129         return batadv_send_skb_packet(skb, hard_iface, batadv_broadcast_addr);
130 }
131 
132 int batadv_send_unicast_skb(struct sk_buff *skb,
133                             struct batadv_neigh_node *neigh)
134 {
135 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
136         struct batadv_hardif_neigh_node *hardif_neigh;
137 #endif
138         int ret;
139 
140         ret = batadv_send_skb_packet(skb, neigh->if_incoming, neigh->addr);
141 
142 #ifdef CONFIG_BATMAN_ADV_BATMAN_V
143         hardif_neigh = batadv_hardif_neigh_get(neigh->if_incoming, neigh->addr);
144 
145         if ((hardif_neigh) && (ret != NET_XMIT_DROP))
146                 hardif_neigh->bat_v.last_unicast_tx = jiffies;
147 
148         if (hardif_neigh)
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  */
170 int 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(&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         /* try to network code the packet, if it is received on an interface
199          * (i.e. being forwarded). If the packet originates from this node or if
200          * network coding fails, then send the packet as usual.
201          */
202         if (recv_if && batadv_nc_skb_forward(skb, neigh_node))
203                 ret = -EINPROGRESS;
204         else
205                 ret = batadv_send_unicast_skb(skb, neigh_node);
206 
207         /* skb was consumed */
208         skb = NULL;
209 
210 put_neigh_node:
211         batadv_neigh_node_put(neigh_node);
212 free_skb:
213         kfree_skb(skb);
214 
215         return ret;
216 }
217 
218 /**
219  * batadv_send_skb_push_fill_unicast - extend the buffer and initialize the
220  *  common fields for unicast packets
221  * @skb: the skb carrying the unicast header to initialize
222  * @hdr_size: amount of bytes to push at the beginning of the skb
223  * @orig_node: the destination node
224  *
225  * Return: false if the buffer extension was not possible or true otherwise.
226  */
227 static bool
228 batadv_send_skb_push_fill_unicast(struct sk_buff *skb, int hdr_size,
229                                   struct batadv_orig_node *orig_node)
230 {
231         struct batadv_unicast_packet *unicast_packet;
232         u8 ttvn = (u8)atomic_read(&orig_node->last_ttvn);
233 
234         if (batadv_skb_head_push(skb, hdr_size) < 0)
235                 return false;
236 
237         unicast_packet = (struct batadv_unicast_packet *)skb->data;
238         unicast_packet->version = BATADV_COMPAT_VERSION;
239         /* batman packet type: unicast */
240         unicast_packet->packet_type = BATADV_UNICAST;
241         /* set unicast ttl */
242         unicast_packet->ttl = BATADV_TTL;
243         /* copy the destination for faster routing */
244         ether_addr_copy(unicast_packet->dest, orig_node->orig);
245         /* set the destination tt version number */
246         unicast_packet->ttvn = ttvn;
247 
248         return true;
249 }
250 
251 /**
252  * batadv_send_skb_prepare_unicast - encapsulate an skb with a unicast header
253  * @skb: the skb containing the payload to encapsulate
254  * @orig_node: the destination node
255  *
256  * Return: false if the payload could not be encapsulated or true otherwise.
257  */
258 static bool batadv_send_skb_prepare_unicast(struct sk_buff *skb,
259                                             struct batadv_orig_node *orig_node)
260 {
261         size_t uni_size = sizeof(struct batadv_unicast_packet);
262 
263         return batadv_send_skb_push_fill_unicast(skb, uni_size, orig_node);
264 }
265 
266 /**
267  * batadv_send_skb_prepare_unicast_4addr - encapsulate an skb with a
268  *  unicast 4addr header
269  * @bat_priv: the bat priv with all the soft interface information
270  * @skb: the skb containing the payload to encapsulate
271  * @orig: the destination node
272  * @packet_subtype: the unicast 4addr packet subtype to use
273  *
274  * Return: false if the payload could not be encapsulated or true otherwise.
275  */
276 bool batadv_send_skb_prepare_unicast_4addr(struct batadv_priv *bat_priv,
277                                            struct sk_buff *skb,
278                                            struct batadv_orig_node *orig,
279                                            int packet_subtype)
280 {
281         struct batadv_hard_iface *primary_if;
282         struct batadv_unicast_4addr_packet *uc_4addr_packet;
283         bool ret = false;
284 
285         primary_if = batadv_primary_if_get_selected(bat_priv);
286         if (!primary_if)
287                 goto out;
288 
289         /* Pull the header space and fill the unicast_packet substructure.
290          * We can do that because the first member of the uc_4addr_packet
291          * is of type struct unicast_packet
292          */
293         if (!batadv_send_skb_push_fill_unicast(skb, sizeof(*uc_4addr_packet),
294                                                orig))
295                 goto out;
296 
297         uc_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
298         uc_4addr_packet->u.packet_type = BATADV_UNICAST_4ADDR;
299         ether_addr_copy(uc_4addr_packet->src, primary_if->net_dev->dev_addr);
300         uc_4addr_packet->subtype = packet_subtype;
301         uc_4addr_packet->reserved = 0;
302 
303         ret = true;
304 out:
305         if (primary_if)
306                 batadv_hardif_put(primary_if);
307         return ret;
308 }
309 
310 /**
311  * batadv_send_skb_unicast - encapsulate and send an skb via unicast
312  * @bat_priv: the bat priv with all the soft interface information
313  * @skb: payload to send
314  * @packet_type: the batman unicast packet type to use
315  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
316  *  4addr packets)
317  * @orig_node: the originator to send the packet to
318  * @vid: the vid to be used to search the translation table
319  *
320  * Wrap the given skb into a batman-adv unicast or unicast-4addr header
321  * depending on whether BATADV_UNICAST or BATADV_UNICAST_4ADDR was supplied
322  * as packet_type. Then send this frame to the given orig_node.
323  *
324  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
325  */
326 int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
327                             struct sk_buff *skb, int packet_type,
328                             int packet_subtype,
329                             struct batadv_orig_node *orig_node,
330                             unsigned short vid)
331 {
332         struct batadv_unicast_packet *unicast_packet;
333         struct ethhdr *ethhdr;
334         int ret = NET_XMIT_DROP;
335 
336         if (!orig_node)
337                 goto out;
338 
339         switch (packet_type) {
340         case BATADV_UNICAST:
341                 if (!batadv_send_skb_prepare_unicast(skb, orig_node))
342                         goto out;
343                 break;
344         case BATADV_UNICAST_4ADDR:
345                 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
346                                                            orig_node,
347                                                            packet_subtype))
348                         goto out;
349                 break;
350         default:
351                 /* this function supports UNICAST and UNICAST_4ADDR only. It
352                  * should never be invoked with any other packet type
353                  */
354                 goto out;
355         }
356 
357         /* skb->data might have been reallocated by
358          * batadv_send_skb_prepare_unicast{,_4addr}()
359          */
360         ethhdr = eth_hdr(skb);
361         unicast_packet = (struct batadv_unicast_packet *)skb->data;
362 
363         /* inform the destination node that we are still missing a correct route
364          * for this client. The destination will receive this packet and will
365          * try to reroute it because the ttvn contained in the header is less
366          * than the current one
367          */
368         if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest, vid))
369                 unicast_packet->ttvn = unicast_packet->ttvn - 1;
370 
371         ret = batadv_send_skb_to_orig(skb, orig_node, NULL);
372          /* skb was consumed */
373         skb = NULL;
374 
375 out:
376         kfree_skb(skb);
377         return ret;
378 }
379 
380 /**
381  * batadv_send_skb_via_tt_generic - send an skb via TT lookup
382  * @bat_priv: the bat priv with all the soft interface information
383  * @skb: payload to send
384  * @packet_type: the batman unicast packet type to use
385  * @packet_subtype: the unicast 4addr packet subtype (only relevant for unicast
386  *  4addr packets)
387  * @dst_hint: can be used to override the destination contained in the skb
388  * @vid: the vid to be used to search the translation table
389  *
390  * Look up the recipient node for the destination address in the ethernet
391  * header via the translation table. Wrap the given skb into a batman-adv
392  * unicast or unicast-4addr header depending on whether BATADV_UNICAST or
393  * BATADV_UNICAST_4ADDR was supplied as packet_type. Then send this frame
394  * to the according destination node.
395  *
396  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
397  */
398 int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
399                                    struct sk_buff *skb, int packet_type,
400                                    int packet_subtype, u8 *dst_hint,
401                                    unsigned short vid)
402 {
403         struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
404         struct batadv_orig_node *orig_node;
405         u8 *src, *dst;
406         int ret;
407 
408         src = ethhdr->h_source;
409         dst = ethhdr->h_dest;
410 
411         /* if we got an hint! let's send the packet to this client (if any) */
412         if (dst_hint) {
413                 src = NULL;
414                 dst = dst_hint;
415         }
416         orig_node = batadv_transtable_search(bat_priv, src, dst, vid);
417 
418         ret = batadv_send_skb_unicast(bat_priv, skb, packet_type,
419                                       packet_subtype, orig_node, vid);
420 
421         if (orig_node)
422                 batadv_orig_node_put(orig_node);
423 
424         return ret;
425 }
426 
427 /**
428  * batadv_send_skb_via_gw - send an skb via gateway lookup
429  * @bat_priv: the bat priv with all the soft interface information
430  * @skb: payload to send
431  * @vid: the vid to be used to search the translation table
432  *
433  * Look up the currently selected gateway. Wrap the given skb into a batman-adv
434  * unicast header and send this frame to this gateway node.
435  *
436  * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
437  */
438 int batadv_send_skb_via_gw(struct batadv_priv *bat_priv, struct sk_buff *skb,
439                            unsigned short vid)
440 {
441         struct batadv_orig_node *orig_node;
442         int ret;
443 
444         orig_node = batadv_gw_get_selected_orig(bat_priv);
445         ret = batadv_send_skb_unicast(bat_priv, skb, BATADV_UNICAST_4ADDR,
446                                       BATADV_P_DATA, orig_node, vid);
447 
448         if (orig_node)
449                 batadv_orig_node_put(orig_node);
450 
451         return ret;
452 }
453 
454 /**
455  * batadv_forw_packet_free - free a forwarding packet
456  * @forw_packet: The packet to free
457  * @dropped: whether the packet is freed because is is dropped
458  *
459  * This frees a forwarding packet and releases any resources it might
460  * have claimed.
461  */
462 void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet,
463                              bool dropped)
464 {
465         if (dropped)
466                 kfree_skb(forw_packet->skb);
467         else
468                 consume_skb(forw_packet->skb);
469 
470         if (forw_packet->if_incoming)
471                 batadv_hardif_put(forw_packet->if_incoming);
472         if (forw_packet->if_outgoing)
473                 batadv_hardif_put(forw_packet->if_outgoing);
474         if (forw_packet->queue_left)
475                 atomic_inc(forw_packet->queue_left);
476         kfree(forw_packet);
477 }
478 
479 /**
480  * batadv_forw_packet_alloc - allocate a forwarding packet
481  * @if_incoming: The (optional) if_incoming to be grabbed
482  * @if_outgoing: The (optional) if_outgoing to be grabbed
483  * @queue_left: The (optional) queue counter to decrease
484  * @bat_priv: The bat_priv for the mesh of this forw_packet
485  * @skb: The raw packet this forwarding packet shall contain
486  *
487  * Allocates a forwarding packet and tries to get a reference to the
488  * (optional) if_incoming, if_outgoing and queue_left. If queue_left
489  * is NULL then bat_priv is optional, too.
490  *
491  * Return: An allocated forwarding packet on success, NULL otherwise.
492  */
493 struct batadv_forw_packet *
494 batadv_forw_packet_alloc(struct batadv_hard_iface *if_incoming,
495                          struct batadv_hard_iface *if_outgoing,
496                          atomic_t *queue_left,
497                          struct batadv_priv *bat_priv,
498                          struct sk_buff *skb)
499 {
500         struct batadv_forw_packet *forw_packet;
501         const char *qname;
502 
503         if (queue_left && !batadv_atomic_dec_not_zero(queue_left)) {
504                 qname = "unknown";
505 
506                 if (queue_left == &bat_priv->bcast_queue_left)
507                         qname = "bcast";
508 
509                 if (queue_left == &bat_priv->batman_queue_left)
510                         qname = "batman";
511 
512                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
513                            "%s queue is full\n", qname);
514 
515                 return NULL;
516         }
517 
518         forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
519         if (!forw_packet)
520                 goto err;
521 
522         if (if_incoming)
523                 kref_get(&if_incoming->refcount);
524 
525         if (if_outgoing)
526                 kref_get(&if_outgoing->refcount);
527 
528         INIT_HLIST_NODE(&forw_packet->list);
529         INIT_HLIST_NODE(&forw_packet->cleanup_list);
530         forw_packet->skb = skb;
531         forw_packet->queue_left = queue_left;
532         forw_packet->if_incoming = if_incoming;
533         forw_packet->if_outgoing = if_outgoing;
534         forw_packet->num_packets = 0;
535 
536         return forw_packet;
537 
538 err:
539         if (queue_left)
540                 atomic_inc(queue_left);
541 
542         return NULL;
543 }
544 
545 /**
546  * batadv_forw_packet_was_stolen - check whether someone stole this packet
547  * @forw_packet: the forwarding packet to check
548  *
549  * This function checks whether the given forwarding packet was claimed by
550  * someone else for free().
551  *
552  * Return: True if someone stole it, false otherwise.
553  */
554 static bool
555 batadv_forw_packet_was_stolen(struct batadv_forw_packet *forw_packet)
556 {
557         return !hlist_unhashed(&forw_packet->cleanup_list);
558 }
559 
560 /**
561  * batadv_forw_packet_steal - claim a forw_packet for free()
562  * @forw_packet: the forwarding packet to steal
563  * @lock: a key to the store to steal from (e.g. forw_{bat,bcast}_list_lock)
564  *
565  * This function tries to steal a specific forw_packet from global
566  * visibility for the purpose of getting it for free(). That means
567  * the caller is *not* allowed to requeue it afterwards.
568  *
569  * Return: True if stealing was successful. False if someone else stole it
570  * before us.
571  */
572 bool batadv_forw_packet_steal(struct batadv_forw_packet *forw_packet,
573                               spinlock_t *lock)
574 {
575         /* did purging routine steal it earlier? */
576         spin_lock_bh(lock);
577         if (batadv_forw_packet_was_stolen(forw_packet)) {
578                 spin_unlock_bh(lock);
579                 return false;
580         }
581 
582         hlist_del_init(&forw_packet->list);
583 
584         /* Just to spot misuse of this function */
585         hlist_add_fake(&forw_packet->cleanup_list);
586 
587         spin_unlock_bh(lock);
588         return true;
589 }
590 
591 /**
592  * batadv_forw_packet_list_steal - claim a list of forward packets for free()
593  * @forw_list: the to be stolen forward packets
594  * @cleanup_list: a backup pointer, to be able to dispose the packet later
595  * @hard_iface: the interface to steal forward packets from
596  *
597  * This function claims responsibility to free any forw_packet queued on the
598  * given hard_iface. If hard_iface is NULL forwarding packets on all hard
599  * interfaces will be claimed.
600  *
601  * The packets are being moved from the forw_list to the cleanup_list and
602  * by that allows already running threads to notice the claiming.
603  */
604 static void
605 batadv_forw_packet_list_steal(struct hlist_head *forw_list,
606                               struct hlist_head *cleanup_list,
607                               const struct batadv_hard_iface *hard_iface)
608 {
609         struct batadv_forw_packet *forw_packet;
610         struct hlist_node *safe_tmp_node;
611 
612         hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
613                                   forw_list, list) {
614                 /* if purge_outstanding_packets() was called with an argument
615                  * we delete only packets belonging to the given interface
616                  */
617                 if (hard_iface &&
618                     (forw_packet->if_incoming != hard_iface) &&
619                     (forw_packet->if_outgoing != hard_iface))
620                         continue;
621 
622                 hlist_del(&forw_packet->list);
623                 hlist_add_head(&forw_packet->cleanup_list, cleanup_list);
624         }
625 }
626 
627 /**
628  * batadv_forw_packet_list_free - free a list of forward packets
629  * @head: a list of to be freed forw_packets
630  *
631  * This function cancels the scheduling of any packet in the provided list,
632  * waits for any possibly running packet forwarding thread to finish and
633  * finally, safely frees this forward packet.
634  *
635  * This function might sleep.
636  */
637 static void batadv_forw_packet_list_free(struct hlist_head *head)
638 {
639         struct batadv_forw_packet *forw_packet;
640         struct hlist_node *safe_tmp_node;
641 
642         hlist_for_each_entry_safe(forw_packet, safe_tmp_node, head,
643                                   cleanup_list) {
644                 cancel_delayed_work_sync(&forw_packet->delayed_work);
645 
646                 hlist_del(&forw_packet->cleanup_list);
647                 batadv_forw_packet_free(forw_packet, true);
648         }
649 }
650 
651 /**
652  * batadv_forw_packet_queue - try to queue a forwarding packet
653  * @forw_packet: the forwarding packet to queue
654  * @lock: a key to the store (e.g. forw_{bat,bcast}_list_lock)
655  * @head: the shelve to queue it on (e.g. forw_{bat,bcast}_list)
656  * @send_time: timestamp (jiffies) when the packet is to be sent
657  *
658  * This function tries to (re)queue a forwarding packet. Requeuing
659  * is prevented if the according interface is shutting down
660  * (e.g. if batadv_forw_packet_list_steal() was called for this
661  * packet earlier).
662  *
663  * Calling batadv_forw_packet_queue() after a call to
664  * batadv_forw_packet_steal() is forbidden!
665  *
666  * Caller needs to ensure that forw_packet->delayed_work was initialized.
667  */
668 static void batadv_forw_packet_queue(struct batadv_forw_packet *forw_packet,
669                                      spinlock_t *lock, struct hlist_head *head,
670                                      unsigned long send_time)
671 {
672         spin_lock_bh(lock);
673 
674         /* did purging routine steal it from us? */
675         if (batadv_forw_packet_was_stolen(forw_packet)) {
676                 /* If you got it for free() without trouble, then
677                  * don't get back into the queue after stealing...
678                  */
679                 WARN_ONCE(hlist_fake(&forw_packet->cleanup_list),
680                           "Requeuing after batadv_forw_packet_steal() not allowed!\n");
681 
682                 spin_unlock_bh(lock);
683                 return;
684         }
685 
686         hlist_del_init(&forw_packet->list);
687         hlist_add_head(&forw_packet->list, head);
688 
689         queue_delayed_work(batadv_event_workqueue,
690                            &forw_packet->delayed_work,
691                            send_time - jiffies);
692         spin_unlock_bh(lock);
693 }
694 
695 /**
696  * batadv_forw_packet_bcast_queue - try to queue a broadcast packet
697  * @bat_priv: the bat priv with all the soft interface information
698  * @forw_packet: the forwarding packet to queue
699  * @send_time: timestamp (jiffies) when the packet is to be sent
700  *
701  * This function tries to (re)queue a broadcast packet.
702  *
703  * Caller needs to ensure that forw_packet->delayed_work was initialized.
704  */
705 static void
706 batadv_forw_packet_bcast_queue(struct batadv_priv *bat_priv,
707                                struct batadv_forw_packet *forw_packet,
708                                unsigned long send_time)
709 {
710         batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bcast_list_lock,
711                                  &bat_priv->forw_bcast_list, send_time);
712 }
713 
714 /**
715  * batadv_forw_packet_ogmv1_queue - try to queue an OGMv1 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 an OGMv1 packet.
721  *
722  * Caller needs to ensure that forw_packet->delayed_work was initialized.
723  */
724 void batadv_forw_packet_ogmv1_queue(struct batadv_priv *bat_priv,
725                                     struct batadv_forw_packet *forw_packet,
726                                     unsigned long send_time)
727 {
728         batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bat_list_lock,
729                                  &bat_priv->forw_bat_list, send_time);
730 }
731 
732 /**
733  * batadv_add_bcast_packet_to_list - queue broadcast packet for multiple sends
734  * @bat_priv: the bat priv with all the soft interface information
735  * @skb: broadcast packet to add
736  * @delay: number of jiffies to wait before sending
737  * @own_packet: true if it is a self-generated broadcast packet
738  *
739  * add a broadcast packet to the queue and setup timers. broadcast packets
740  * are sent multiple times to increase probability for being received.
741  *
742  * The skb is not consumed, so the caller should make sure that the
743  * skb is freed.
744  *
745  * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
746  */
747 int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
748                                     const struct sk_buff *skb,
749                                     unsigned long delay,
750                                     bool own_packet)
751 {
752         struct batadv_hard_iface *primary_if;
753         struct batadv_forw_packet *forw_packet;
754         struct batadv_bcast_packet *bcast_packet;
755         struct sk_buff *newskb;
756 
757         primary_if = batadv_primary_if_get_selected(bat_priv);
758         if (!primary_if)
759                 goto err;
760 
761         newskb = skb_copy(skb, GFP_ATOMIC);
762         if (!newskb) {
763                 batadv_hardif_put(primary_if);
764                 goto err;
765         }
766 
767         forw_packet = batadv_forw_packet_alloc(primary_if, NULL,
768                                                &bat_priv->bcast_queue_left,
769                                                bat_priv, newskb);
770         batadv_hardif_put(primary_if);
771         if (!forw_packet)
772                 goto err_packet_free;
773 
774         /* as we have a copy now, it is safe to decrease the TTL */
775         bcast_packet = (struct batadv_bcast_packet *)newskb->data;
776         bcast_packet->ttl--;
777 
778         forw_packet->own = own_packet;
779 
780         INIT_DELAYED_WORK(&forw_packet->delayed_work,
781                           batadv_send_outstanding_bcast_packet);
782 
783         batadv_forw_packet_bcast_queue(bat_priv, forw_packet, jiffies + delay);
784         return NETDEV_TX_OK;
785 
786 err_packet_free:
787         kfree_skb(newskb);
788 err:
789         return NETDEV_TX_BUSY;
790 }
791 
792 /**
793  * batadv_forw_packet_bcasts_left - check if a retransmission is necessary
794  * @forw_packet: the forwarding packet to check
795  * @hard_iface: the interface to check on
796  *
797  * Checks whether a given packet has any (re)transmissions left on the provided
798  * interface.
799  *
800  * hard_iface may be NULL: In that case the number of transmissions this skb had
801  * so far is compared with the maximum amount of retransmissions independent of
802  * any interface instead.
803  *
804  * Return: True if (re)transmissions are left, false otherwise.
805  */
806 static bool
807 batadv_forw_packet_bcasts_left(struct batadv_forw_packet *forw_packet,
808                                struct batadv_hard_iface *hard_iface)
809 {
810         unsigned int max;
811 
812         if (hard_iface)
813                 max = hard_iface->num_bcasts;
814         else
815                 max = BATADV_NUM_BCASTS_MAX;
816 
817         return BATADV_SKB_CB(forw_packet->skb)->num_bcasts < max;
818 }
819 
820 /**
821  * batadv_forw_packet_bcasts_inc - increment retransmission counter of a packet
822  * @forw_packet: the packet to increase the counter for
823  */
824 static void
825 batadv_forw_packet_bcasts_inc(struct batadv_forw_packet *forw_packet)
826 {
827         BATADV_SKB_CB(forw_packet->skb)->num_bcasts++;
828 }
829 
830 /**
831  * batadv_forw_packet_is_rebroadcast - check packet for previous transmissions
832  * @forw_packet: the packet to check
833  *
834  * Return: True if this packet was transmitted before, false otherwise.
835  */
836 bool batadv_forw_packet_is_rebroadcast(struct batadv_forw_packet *forw_packet)
837 {
838         return BATADV_SKB_CB(forw_packet->skb)->num_bcasts > 0;
839 }
840 
841 static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
842 {
843         struct batadv_hard_iface *hard_iface;
844         struct batadv_hardif_neigh_node *neigh_node;
845         struct delayed_work *delayed_work;
846         struct batadv_forw_packet *forw_packet;
847         struct batadv_bcast_packet *bcast_packet;
848         struct sk_buff *skb1;
849         struct net_device *soft_iface;
850         struct batadv_priv *bat_priv;
851         unsigned long send_time = jiffies + msecs_to_jiffies(5);
852         bool dropped = false;
853         u8 *neigh_addr;
854         u8 *orig_neigh;
855         int ret = 0;
856 
857         delayed_work = to_delayed_work(work);
858         forw_packet = container_of(delayed_work, struct batadv_forw_packet,
859                                    delayed_work);
860         soft_iface = forw_packet->if_incoming->soft_iface;
861         bat_priv = netdev_priv(soft_iface);
862 
863         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
864                 dropped = true;
865                 goto out;
866         }
867 
868         if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet)) {
869                 dropped = true;
870                 goto out;
871         }
872 
873         bcast_packet = (struct batadv_bcast_packet *)forw_packet->skb->data;
874 
875         /* rebroadcast packet */
876         rcu_read_lock();
877         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
878                 if (hard_iface->soft_iface != soft_iface)
879                         continue;
880 
881                 if (!batadv_forw_packet_bcasts_left(forw_packet, hard_iface))
882                         continue;
883 
884                 if (forw_packet->own) {
885                         neigh_node = NULL;
886                 } else {
887                         neigh_addr = eth_hdr(forw_packet->skb)->h_source;
888                         neigh_node = batadv_hardif_neigh_get(hard_iface,
889                                                              neigh_addr);
890                 }
891 
892                 orig_neigh = neigh_node ? neigh_node->orig : NULL;
893 
894                 ret = batadv_hardif_no_broadcast(hard_iface, bcast_packet->orig,
895                                                  orig_neigh);
896 
897                 if (ret) {
898                         char *type;
899 
900                         switch (ret) {
901                         case BATADV_HARDIF_BCAST_NORECIPIENT:
902                                 type = "no neighbor";
903                                 break;
904                         case BATADV_HARDIF_BCAST_DUPFWD:
905                                 type = "single neighbor is source";
906                                 break;
907                         case BATADV_HARDIF_BCAST_DUPORIG:
908                                 type = "single neighbor is originator";
909                                 break;
910                         default:
911                                 type = "unknown";
912                         }
913 
914                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "BCAST packet from orig %pM on %s surpressed: %s\n",
915                                    bcast_packet->orig,
916                                    hard_iface->net_dev->name, type);
917 
918                         if (neigh_node)
919                                 batadv_hardif_neigh_put(neigh_node);
920 
921                         continue;
922                 }
923 
924                 if (neigh_node)
925                         batadv_hardif_neigh_put(neigh_node);
926 
927                 if (!kref_get_unless_zero(&hard_iface->refcount))
928                         continue;
929 
930                 /* send a copy of the saved skb */
931                 skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
932                 if (skb1)
933                         batadv_send_broadcast_skb(skb1, hard_iface);
934 
935                 batadv_hardif_put(hard_iface);
936         }
937         rcu_read_unlock();
938 
939         batadv_forw_packet_bcasts_inc(forw_packet);
940 
941         /* if we still have some more bcasts to send */
942         if (batadv_forw_packet_bcasts_left(forw_packet, NULL)) {
943                 batadv_forw_packet_bcast_queue(bat_priv, forw_packet,
944                                                send_time);
945                 return;
946         }
947 
948 out:
949         /* do we get something for free()? */
950         if (batadv_forw_packet_steal(forw_packet,
951                                      &bat_priv->forw_bcast_list_lock))
952                 batadv_forw_packet_free(forw_packet, dropped);
953 }
954 
955 /**
956  * batadv_purge_outstanding_packets - stop/purge scheduled bcast/OGMv1 packets
957  * @bat_priv: the bat priv with all the soft interface information
958  * @hard_iface: the hard interface to cancel and purge bcast/ogm packets on
959  *
960  * This method cancels and purges any broadcast and OGMv1 packet on the given
961  * hard_iface. If hard_iface is NULL, broadcast and OGMv1 packets on all hard
962  * interfaces will be canceled and purged.
963  *
964  * This function might sleep.
965  */
966 void
967 batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
968                                  const struct batadv_hard_iface *hard_iface)
969 {
970         struct hlist_head head = HLIST_HEAD_INIT;
971 
972         if (hard_iface)
973                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
974                            "purge_outstanding_packets(): %s\n",
975                            hard_iface->net_dev->name);
976         else
977                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
978                            "purge_outstanding_packets()\n");
979 
980         /* claim bcast list for free() */
981         spin_lock_bh(&bat_priv->forw_bcast_list_lock);
982         batadv_forw_packet_list_steal(&bat_priv->forw_bcast_list, &head,
983                                       hard_iface);
984         spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
985 
986         /* claim batman packet list for free() */
987         spin_lock_bh(&bat_priv->forw_bat_list_lock);
988         batadv_forw_packet_list_steal(&bat_priv->forw_bat_list, &head,
989                                       hard_iface);
990         spin_unlock_bh(&bat_priv->forw_bat_list_lock);
991 
992         /* then cancel or wait for packet workers to finish and free */
993         batadv_forw_packet_list_free(&head);
994 }
995 

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