xref: /linux/net/batman-adv/send.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
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/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  */
batadv_send_skb_packet(struct sk_buff * skb,struct batadv_hard_iface * hard_iface,const u8 * dst_addr)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  */
batadv_send_broadcast_skb(struct sk_buff * skb,struct batadv_hard_iface * hard_iface)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  */
batadv_send_unicast_skb(struct sk_buff * skb,struct batadv_neigh_node * neigh)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  */
batadv_send_skb_to_orig(struct sk_buff * skb,struct batadv_orig_node * orig_node,struct batadv_hard_iface * recv_if)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
batadv_send_skb_push_fill_unicast(struct sk_buff * skb,int hdr_size,struct batadv_orig_node * orig_node)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  */
batadv_send_skb_prepare_unicast(struct sk_buff * skb,struct batadv_orig_node * orig_node)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  */
batadv_send_skb_prepare_unicast_4addr(struct batadv_priv * bat_priv,struct sk_buff * skb,struct batadv_orig_node * orig,int packet_subtype)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  */
batadv_send_skb_unicast(struct batadv_priv * bat_priv,struct sk_buff * skb,int packet_type,int packet_subtype,struct batadv_orig_node * orig_node,unsigned short vid)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  */
batadv_send_skb_via_tt_generic(struct batadv_priv * bat_priv,struct sk_buff * skb,int packet_type,int packet_subtype,u8 * dst_hint,unsigned short vid)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  */
batadv_send_skb_via_gw(struct batadv_priv * bat_priv,struct sk_buff * skb,unsigned short vid)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  */
batadv_forw_packet_free(struct batadv_forw_packet * forw_packet,bool dropped)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 *
batadv_forw_packet_alloc(struct batadv_hard_iface * if_incoming,struct batadv_hard_iface * if_outgoing,atomic_t * queue_left,struct batadv_priv * bat_priv,struct sk_buff * skb)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
batadv_forw_packet_was_stolen(struct batadv_forw_packet * forw_packet)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  */
batadv_forw_packet_steal(struct batadv_forw_packet * forw_packet,spinlock_t * lock)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
batadv_forw_packet_list_steal(struct hlist_head * forw_list,struct hlist_head * cleanup_list,const struct batadv_hard_iface * hard_iface)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  */
batadv_forw_packet_list_free(struct hlist_head * head)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  */
batadv_forw_packet_queue(struct batadv_forw_packet * forw_packet,spinlock_t * lock,struct hlist_head * head,unsigned long send_time)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
batadv_forw_packet_bcast_queue(struct batadv_priv * bat_priv,struct batadv_forw_packet * forw_packet,unsigned long send_time)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  */
batadv_forw_packet_ogmv1_queue(struct batadv_priv * bat_priv,struct batadv_forw_packet * forw_packet,unsigned long send_time)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  */
batadv_forw_bcast_packet_to_list(struct batadv_priv * bat_priv,struct sk_buff * skb,unsigned long delay,bool own_packet,struct batadv_hard_iface * if_in,struct batadv_hard_iface * if_out)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  */
batadv_forw_bcast_packet_if(struct batadv_priv * bat_priv,struct sk_buff * skb,unsigned long delay,bool own_packet,struct batadv_hard_iface * if_in,struct batadv_hard_iface * if_out)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  */
batadv_send_no_broadcast(struct batadv_priv * bat_priv,struct sk_buff * skb,bool own_packet,struct batadv_hard_iface * if_out)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  */
__batadv_forw_bcast_packet(struct batadv_priv * bat_priv,struct sk_buff * skb,unsigned long delay,bool own_packet)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  */
batadv_forw_bcast_packet(struct batadv_priv * bat_priv,struct sk_buff * skb,unsigned long delay,bool own_packet)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  */
batadv_send_bcast_packet(struct batadv_priv * bat_priv,struct sk_buff * skb,unsigned long delay,bool own_packet)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
batadv_forw_packet_bcasts_left(struct batadv_forw_packet * forw_packet)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
batadv_forw_packet_bcasts_dec(struct batadv_forw_packet * forw_packet)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  */
batadv_forw_packet_is_rebroadcast(struct batadv_forw_packet * forw_packet)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  */
batadv_send_outstanding_bcast_packet(struct work_struct * work)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
batadv_purge_outstanding_packets(struct batadv_priv * bat_priv,const struct batadv_hard_iface * hard_iface)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 }
1136