xref: /openbmc/linux/net/bluetooth/6lowpan.c (revision 1f0214a8)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3    Copyright (c) 2013-2014 Intel Corp.
4 
5 */
6 
7 #include <linux/if_arp.h>
8 #include <linux/netdevice.h>
9 #include <linux/etherdevice.h>
10 #include <linux/module.h>
11 #include <linux/debugfs.h>
12 
13 #include <net/ipv6.h>
14 #include <net/ip6_route.h>
15 #include <net/addrconf.h>
16 #include <net/pkt_sched.h>
17 
18 #include <net/bluetooth/bluetooth.h>
19 #include <net/bluetooth/hci_core.h>
20 #include <net/bluetooth/l2cap.h>
21 
22 #include <net/6lowpan.h> /* for the compression support */
23 
24 #define VERSION "0.1"
25 
26 static struct dentry *lowpan_enable_debugfs;
27 static struct dentry *lowpan_control_debugfs;
28 
29 #define IFACE_NAME_TEMPLATE "bt%d"
30 
31 struct skb_cb {
32 	struct in6_addr addr;
33 	struct in6_addr gw;
34 	struct l2cap_chan *chan;
35 };
36 #define lowpan_cb(skb) ((struct skb_cb *)((skb)->cb))
37 
38 /* The devices list contains those devices that we are acting
39  * as a proxy. The BT 6LoWPAN device is a virtual device that
40  * connects to the Bluetooth LE device. The real connection to
41  * BT device is done via l2cap layer. There exists one
42  * virtual device / one BT 6LoWPAN network (=hciX device).
43  * The list contains struct lowpan_dev elements.
44  */
45 static LIST_HEAD(bt_6lowpan_devices);
46 static DEFINE_SPINLOCK(devices_lock);
47 
48 static bool enable_6lowpan;
49 
50 /* We are listening incoming connections via this channel
51  */
52 static struct l2cap_chan *listen_chan;
53 static DEFINE_MUTEX(set_lock);
54 
55 struct lowpan_peer {
56 	struct list_head list;
57 	struct rcu_head rcu;
58 	struct l2cap_chan *chan;
59 
60 	/* peer addresses in various formats */
61 	unsigned char lladdr[ETH_ALEN];
62 	struct in6_addr peer_addr;
63 };
64 
65 struct lowpan_btle_dev {
66 	struct list_head list;
67 
68 	struct hci_dev *hdev;
69 	struct net_device *netdev;
70 	struct list_head peers;
71 	atomic_t peer_count; /* number of items in peers list */
72 
73 	struct work_struct delete_netdev;
74 	struct delayed_work notify_peers;
75 };
76 
77 static inline struct lowpan_btle_dev *
78 lowpan_btle_dev(const struct net_device *netdev)
79 {
80 	return (struct lowpan_btle_dev *)lowpan_dev(netdev)->priv;
81 }
82 
83 static inline void peer_add(struct lowpan_btle_dev *dev,
84 			    struct lowpan_peer *peer)
85 {
86 	list_add_rcu(&peer->list, &dev->peers);
87 	atomic_inc(&dev->peer_count);
88 }
89 
90 static inline bool peer_del(struct lowpan_btle_dev *dev,
91 			    struct lowpan_peer *peer)
92 {
93 	list_del_rcu(&peer->list);
94 	kfree_rcu(peer, rcu);
95 
96 	module_put(THIS_MODULE);
97 
98 	if (atomic_dec_and_test(&dev->peer_count)) {
99 		BT_DBG("last peer");
100 		return true;
101 	}
102 
103 	return false;
104 }
105 
106 static inline struct lowpan_peer *
107 __peer_lookup_chan(struct lowpan_btle_dev *dev, struct l2cap_chan *chan)
108 {
109 	struct lowpan_peer *peer;
110 
111 	list_for_each_entry_rcu(peer, &dev->peers, list) {
112 		if (peer->chan == chan)
113 			return peer;
114 	}
115 
116 	return NULL;
117 }
118 
119 static inline struct lowpan_peer *
120 __peer_lookup_conn(struct lowpan_btle_dev *dev, struct l2cap_conn *conn)
121 {
122 	struct lowpan_peer *peer;
123 
124 	list_for_each_entry_rcu(peer, &dev->peers, list) {
125 		if (peer->chan->conn == conn)
126 			return peer;
127 	}
128 
129 	return NULL;
130 }
131 
132 static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_btle_dev *dev,
133 						  struct in6_addr *daddr,
134 						  struct sk_buff *skb)
135 {
136 	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
137 	int count = atomic_read(&dev->peer_count);
138 	const struct in6_addr *nexthop;
139 	struct lowpan_peer *peer;
140 	struct neighbour *neigh;
141 
142 	BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);
143 
144 	if (!rt) {
145 		if (ipv6_addr_any(&lowpan_cb(skb)->gw)) {
146 			/* There is neither route nor gateway,
147 			 * probably the destination is a direct peer.
148 			 */
149 			nexthop = daddr;
150 		} else {
151 			/* There is a known gateway
152 			 */
153 			nexthop = &lowpan_cb(skb)->gw;
154 		}
155 	} else {
156 		nexthop = rt6_nexthop(rt, daddr);
157 
158 		/* We need to remember the address because it is needed
159 		 * by bt_xmit() when sending the packet. In bt_xmit(), the
160 		 * destination routing info is not set.
161 		 */
162 		memcpy(&lowpan_cb(skb)->gw, nexthop, sizeof(struct in6_addr));
163 	}
164 
165 	BT_DBG("gw %pI6c", nexthop);
166 
167 	rcu_read_lock();
168 
169 	list_for_each_entry_rcu(peer, &dev->peers, list) {
170 		BT_DBG("dst addr %pMR dst type %u ip %pI6c",
171 		       &peer->chan->dst, peer->chan->dst_type,
172 		       &peer->peer_addr);
173 
174 		if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
175 			rcu_read_unlock();
176 			return peer;
177 		}
178 	}
179 
180 	/* use the neighbour cache for matching addresses assigned by SLAAC */
181 	neigh = __ipv6_neigh_lookup(dev->netdev, nexthop);
182 	if (neigh) {
183 		list_for_each_entry_rcu(peer, &dev->peers, list) {
184 			if (!memcmp(neigh->ha, peer->lladdr, ETH_ALEN)) {
185 				neigh_release(neigh);
186 				rcu_read_unlock();
187 				return peer;
188 			}
189 		}
190 		neigh_release(neigh);
191 	}
192 
193 	rcu_read_unlock();
194 
195 	return NULL;
196 }
197 
198 static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
199 {
200 	struct lowpan_btle_dev *entry;
201 	struct lowpan_peer *peer = NULL;
202 
203 	rcu_read_lock();
204 
205 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
206 		peer = __peer_lookup_conn(entry, conn);
207 		if (peer)
208 			break;
209 	}
210 
211 	rcu_read_unlock();
212 
213 	return peer;
214 }
215 
216 static struct lowpan_btle_dev *lookup_dev(struct l2cap_conn *conn)
217 {
218 	struct lowpan_btle_dev *entry;
219 	struct lowpan_btle_dev *dev = NULL;
220 
221 	rcu_read_lock();
222 
223 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
224 		if (conn->hcon->hdev == entry->hdev) {
225 			dev = entry;
226 			break;
227 		}
228 	}
229 
230 	rcu_read_unlock();
231 
232 	return dev;
233 }
234 
235 static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
236 {
237 	struct sk_buff *skb_cp;
238 
239 	skb_cp = skb_copy(skb, GFP_ATOMIC);
240 	if (!skb_cp)
241 		return NET_RX_DROP;
242 
243 	return netif_rx(skb_cp);
244 }
245 
246 static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
247 			   struct lowpan_peer *peer)
248 {
249 	const u8 *saddr;
250 
251 	saddr = peer->lladdr;
252 
253 	return lowpan_header_decompress(skb, netdev, netdev->dev_addr, saddr);
254 }
255 
256 static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
257 		    struct lowpan_peer *peer)
258 {
259 	struct sk_buff *local_skb;
260 	int ret;
261 
262 	if (!netif_running(dev))
263 		goto drop;
264 
265 	if (dev->type != ARPHRD_6LOWPAN || !skb->len)
266 		goto drop;
267 
268 	skb_reset_network_header(skb);
269 
270 	skb = skb_share_check(skb, GFP_ATOMIC);
271 	if (!skb)
272 		goto drop;
273 
274 	/* check that it's our buffer */
275 	if (lowpan_is_ipv6(*skb_network_header(skb))) {
276 		/* Pull off the 1-byte of 6lowpan header. */
277 		skb_pull(skb, 1);
278 
279 		/* Copy the packet so that the IPv6 header is
280 		 * properly aligned.
281 		 */
282 		local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
283 					    skb_tailroom(skb), GFP_ATOMIC);
284 		if (!local_skb)
285 			goto drop;
286 
287 		local_skb->protocol = htons(ETH_P_IPV6);
288 		local_skb->pkt_type = PACKET_HOST;
289 		local_skb->dev = dev;
290 
291 		skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
292 
293 		if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
294 			kfree_skb(local_skb);
295 			goto drop;
296 		}
297 
298 		dev->stats.rx_bytes += skb->len;
299 		dev->stats.rx_packets++;
300 
301 		consume_skb(local_skb);
302 		consume_skb(skb);
303 	} else if (lowpan_is_iphc(*skb_network_header(skb))) {
304 		local_skb = skb_clone(skb, GFP_ATOMIC);
305 		if (!local_skb)
306 			goto drop;
307 
308 		local_skb->dev = dev;
309 
310 		ret = iphc_decompress(local_skb, dev, peer);
311 		if (ret < 0) {
312 			BT_DBG("iphc_decompress failed: %d", ret);
313 			kfree_skb(local_skb);
314 			goto drop;
315 		}
316 
317 		local_skb->protocol = htons(ETH_P_IPV6);
318 		local_skb->pkt_type = PACKET_HOST;
319 
320 		if (give_skb_to_upper(local_skb, dev)
321 				!= NET_RX_SUCCESS) {
322 			kfree_skb(local_skb);
323 			goto drop;
324 		}
325 
326 		dev->stats.rx_bytes += skb->len;
327 		dev->stats.rx_packets++;
328 
329 		consume_skb(local_skb);
330 		consume_skb(skb);
331 	} else {
332 		BT_DBG("unknown packet type");
333 		goto drop;
334 	}
335 
336 	return NET_RX_SUCCESS;
337 
338 drop:
339 	dev->stats.rx_dropped++;
340 	return NET_RX_DROP;
341 }
342 
343 /* Packet from BT LE device */
344 static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
345 {
346 	struct lowpan_btle_dev *dev;
347 	struct lowpan_peer *peer;
348 	int err;
349 
350 	peer = lookup_peer(chan->conn);
351 	if (!peer)
352 		return -ENOENT;
353 
354 	dev = lookup_dev(chan->conn);
355 	if (!dev || !dev->netdev)
356 		return -ENOENT;
357 
358 	err = recv_pkt(skb, dev->netdev, peer);
359 	if (err) {
360 		BT_DBG("recv pkt %d", err);
361 		err = -EAGAIN;
362 	}
363 
364 	return err;
365 }
366 
367 static int setup_header(struct sk_buff *skb, struct net_device *netdev,
368 			bdaddr_t *peer_addr, u8 *peer_addr_type)
369 {
370 	struct in6_addr ipv6_daddr;
371 	struct ipv6hdr *hdr;
372 	struct lowpan_btle_dev *dev;
373 	struct lowpan_peer *peer;
374 	u8 *daddr;
375 	int err, status = 0;
376 
377 	hdr = ipv6_hdr(skb);
378 
379 	dev = lowpan_btle_dev(netdev);
380 
381 	memcpy(&ipv6_daddr, &hdr->daddr, sizeof(ipv6_daddr));
382 
383 	if (ipv6_addr_is_multicast(&ipv6_daddr)) {
384 		lowpan_cb(skb)->chan = NULL;
385 		daddr = NULL;
386 	} else {
387 		BT_DBG("dest IP %pI6c", &ipv6_daddr);
388 
389 		/* The packet might be sent to 6lowpan interface
390 		 * because of routing (either via default route
391 		 * or user set route) so get peer according to
392 		 * the destination address.
393 		 */
394 		peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
395 		if (!peer) {
396 			BT_DBG("no such peer");
397 			return -ENOENT;
398 		}
399 
400 		daddr = peer->lladdr;
401 		*peer_addr = peer->chan->dst;
402 		*peer_addr_type = peer->chan->dst_type;
403 		lowpan_cb(skb)->chan = peer->chan;
404 
405 		status = 1;
406 	}
407 
408 	lowpan_header_compress(skb, netdev, daddr, dev->netdev->dev_addr);
409 
410 	err = dev_hard_header(skb, netdev, ETH_P_IPV6, NULL, NULL, 0);
411 	if (err < 0)
412 		return err;
413 
414 	return status;
415 }
416 
417 static int header_create(struct sk_buff *skb, struct net_device *netdev,
418 			 unsigned short type, const void *_daddr,
419 			 const void *_saddr, unsigned int len)
420 {
421 	if (type != ETH_P_IPV6)
422 		return -EINVAL;
423 
424 	return 0;
425 }
426 
427 /* Packet to BT LE device */
428 static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
429 		    struct net_device *netdev)
430 {
431 	struct msghdr msg;
432 	struct kvec iv;
433 	int err;
434 
435 	/* Remember the skb so that we can send EAGAIN to the caller if
436 	 * we run out of credits.
437 	 */
438 	chan->data = skb;
439 
440 	iv.iov_base = skb->data;
441 	iv.iov_len = skb->len;
442 
443 	memset(&msg, 0, sizeof(msg));
444 	iov_iter_kvec(&msg.msg_iter, WRITE, &iv, 1, skb->len);
445 
446 	err = l2cap_chan_send(chan, &msg, skb->len);
447 	if (err > 0) {
448 		netdev->stats.tx_bytes += err;
449 		netdev->stats.tx_packets++;
450 		return 0;
451 	}
452 
453 	if (err < 0)
454 		netdev->stats.tx_errors++;
455 
456 	return err;
457 }
458 
459 static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
460 {
461 	struct sk_buff *local_skb;
462 	struct lowpan_btle_dev *entry;
463 	int err = 0;
464 
465 	rcu_read_lock();
466 
467 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
468 		struct lowpan_peer *pentry;
469 		struct lowpan_btle_dev *dev;
470 
471 		if (entry->netdev != netdev)
472 			continue;
473 
474 		dev = lowpan_btle_dev(entry->netdev);
475 
476 		list_for_each_entry_rcu(pentry, &dev->peers, list) {
477 			int ret;
478 
479 			local_skb = skb_clone(skb, GFP_ATOMIC);
480 
481 			BT_DBG("xmit %s to %pMR type %u IP %pI6c chan %p",
482 			       netdev->name,
483 			       &pentry->chan->dst, pentry->chan->dst_type,
484 			       &pentry->peer_addr, pentry->chan);
485 			ret = send_pkt(pentry->chan, local_skb, netdev);
486 			if (ret < 0)
487 				err = ret;
488 
489 			kfree_skb(local_skb);
490 		}
491 	}
492 
493 	rcu_read_unlock();
494 
495 	return err;
496 }
497 
498 static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
499 {
500 	int err = 0;
501 	bdaddr_t addr;
502 	u8 addr_type;
503 
504 	/* We must take a copy of the skb before we modify/replace the ipv6
505 	 * header as the header could be used elsewhere
506 	 */
507 	skb = skb_unshare(skb, GFP_ATOMIC);
508 	if (!skb)
509 		return NET_XMIT_DROP;
510 
511 	/* Return values from setup_header()
512 	 *  <0 - error, packet is dropped
513 	 *   0 - this is a multicast packet
514 	 *   1 - this is unicast packet
515 	 */
516 	err = setup_header(skb, netdev, &addr, &addr_type);
517 	if (err < 0) {
518 		kfree_skb(skb);
519 		return NET_XMIT_DROP;
520 	}
521 
522 	if (err) {
523 		if (lowpan_cb(skb)->chan) {
524 			BT_DBG("xmit %s to %pMR type %u IP %pI6c chan %p",
525 			       netdev->name, &addr, addr_type,
526 			       &lowpan_cb(skb)->addr, lowpan_cb(skb)->chan);
527 			err = send_pkt(lowpan_cb(skb)->chan, skb, netdev);
528 		} else {
529 			err = -ENOENT;
530 		}
531 	} else {
532 		/* We need to send the packet to every device behind this
533 		 * interface.
534 		 */
535 		err = send_mcast_pkt(skb, netdev);
536 	}
537 
538 	dev_kfree_skb(skb);
539 
540 	if (err)
541 		BT_DBG("ERROR: xmit failed (%d)", err);
542 
543 	return err < 0 ? NET_XMIT_DROP : err;
544 }
545 
546 static int bt_dev_init(struct net_device *dev)
547 {
548 	netdev_lockdep_set_classes(dev);
549 
550 	return 0;
551 }
552 
553 static const struct net_device_ops netdev_ops = {
554 	.ndo_init		= bt_dev_init,
555 	.ndo_start_xmit		= bt_xmit,
556 };
557 
558 static const struct header_ops header_ops = {
559 	.create	= header_create,
560 };
561 
562 static void netdev_setup(struct net_device *dev)
563 {
564 	dev->hard_header_len	= 0;
565 	dev->needed_tailroom	= 0;
566 	dev->flags		= IFF_RUNNING | IFF_MULTICAST;
567 	dev->watchdog_timeo	= 0;
568 	dev->tx_queue_len	= DEFAULT_TX_QUEUE_LEN;
569 
570 	dev->netdev_ops		= &netdev_ops;
571 	dev->header_ops		= &header_ops;
572 	dev->needs_free_netdev	= true;
573 }
574 
575 static struct device_type bt_type = {
576 	.name	= "bluetooth",
577 };
578 
579 static void ifup(struct net_device *netdev)
580 {
581 	int err;
582 
583 	rtnl_lock();
584 	err = dev_open(netdev, NULL);
585 	if (err < 0)
586 		BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
587 	rtnl_unlock();
588 }
589 
590 static void ifdown(struct net_device *netdev)
591 {
592 	rtnl_lock();
593 	dev_close(netdev);
594 	rtnl_unlock();
595 }
596 
597 static void do_notify_peers(struct work_struct *work)
598 {
599 	struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_dev,
600 						   notify_peers.work);
601 
602 	netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
603 }
604 
605 static bool is_bt_6lowpan(struct hci_conn *hcon)
606 {
607 	if (hcon->type != LE_LINK)
608 		return false;
609 
610 	if (!enable_6lowpan)
611 		return false;
612 
613 	return true;
614 }
615 
616 static struct l2cap_chan *chan_create(void)
617 {
618 	struct l2cap_chan *chan;
619 
620 	chan = l2cap_chan_create();
621 	if (!chan)
622 		return NULL;
623 
624 	l2cap_chan_set_defaults(chan);
625 
626 	chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
627 	chan->mode = L2CAP_MODE_LE_FLOWCTL;
628 	chan->imtu = 1280;
629 
630 	return chan;
631 }
632 
633 static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
634 					struct lowpan_btle_dev *dev,
635 					bool new_netdev)
636 {
637 	struct lowpan_peer *peer;
638 
639 	peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
640 	if (!peer)
641 		return NULL;
642 
643 	peer->chan = chan;
644 
645 	baswap((void *)peer->lladdr, &chan->dst);
646 
647 	lowpan_iphc_uncompress_eui48_lladdr(&peer->peer_addr, peer->lladdr);
648 
649 	spin_lock(&devices_lock);
650 	INIT_LIST_HEAD(&peer->list);
651 	peer_add(dev, peer);
652 	spin_unlock(&devices_lock);
653 
654 	/* Notifying peers about us needs to be done without locks held */
655 	if (new_netdev)
656 		INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
657 	schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
658 
659 	return peer->chan;
660 }
661 
662 static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
663 {
664 	struct net_device *netdev;
665 	bdaddr_t addr;
666 	int err;
667 
668 	netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
669 			      IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
670 			      netdev_setup);
671 	if (!netdev)
672 		return -ENOMEM;
673 
674 	netdev->addr_assign_type = NET_ADDR_PERM;
675 	baswap(&addr, &chan->src);
676 	__dev_addr_set(netdev, &addr, sizeof(addr));
677 
678 	netdev->netdev_ops = &netdev_ops;
679 	SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
680 	SET_NETDEV_DEVTYPE(netdev, &bt_type);
681 
682 	*dev = lowpan_btle_dev(netdev);
683 	(*dev)->netdev = netdev;
684 	(*dev)->hdev = chan->conn->hcon->hdev;
685 	INIT_LIST_HEAD(&(*dev)->peers);
686 
687 	spin_lock(&devices_lock);
688 	INIT_LIST_HEAD(&(*dev)->list);
689 	list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
690 	spin_unlock(&devices_lock);
691 
692 	err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
693 	if (err < 0) {
694 		BT_INFO("register_netdev failed %d", err);
695 		spin_lock(&devices_lock);
696 		list_del_rcu(&(*dev)->list);
697 		spin_unlock(&devices_lock);
698 		free_netdev(netdev);
699 		goto out;
700 	}
701 
702 	BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
703 	       netdev->ifindex, &chan->dst, chan->dst_type,
704 	       &chan->src, chan->src_type);
705 	set_bit(__LINK_STATE_PRESENT, &netdev->state);
706 
707 	return 0;
708 
709 out:
710 	return err;
711 }
712 
713 static inline void chan_ready_cb(struct l2cap_chan *chan)
714 {
715 	struct lowpan_btle_dev *dev;
716 	bool new_netdev = false;
717 
718 	dev = lookup_dev(chan->conn);
719 
720 	BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
721 
722 	if (!dev) {
723 		if (setup_netdev(chan, &dev) < 0) {
724 			l2cap_chan_del(chan, -ENOENT);
725 			return;
726 		}
727 		new_netdev = true;
728 	}
729 
730 	if (!try_module_get(THIS_MODULE))
731 		return;
732 
733 	add_peer_chan(chan, dev, new_netdev);
734 	ifup(dev->netdev);
735 }
736 
737 static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
738 {
739 	struct l2cap_chan *chan;
740 
741 	chan = chan_create();
742 	if (!chan)
743 		return NULL;
744 
745 	chan->ops = pchan->ops;
746 
747 	BT_DBG("chan %p pchan %p", chan, pchan);
748 
749 	return chan;
750 }
751 
752 static void delete_netdev(struct work_struct *work)
753 {
754 	struct lowpan_btle_dev *entry = container_of(work,
755 						     struct lowpan_btle_dev,
756 						     delete_netdev);
757 
758 	lowpan_unregister_netdev(entry->netdev);
759 
760 	/* The entry pointer is deleted by the netdev destructor. */
761 }
762 
763 static void chan_close_cb(struct l2cap_chan *chan)
764 {
765 	struct lowpan_btle_dev *entry;
766 	struct lowpan_btle_dev *dev = NULL;
767 	struct lowpan_peer *peer;
768 	int err = -ENOENT;
769 	bool last = false, remove = true;
770 
771 	BT_DBG("chan %p conn %p", chan, chan->conn);
772 
773 	if (chan->conn && chan->conn->hcon) {
774 		if (!is_bt_6lowpan(chan->conn->hcon))
775 			return;
776 
777 		/* If conn is set, then the netdev is also there and we should
778 		 * not remove it.
779 		 */
780 		remove = false;
781 	}
782 
783 	spin_lock(&devices_lock);
784 
785 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
786 		dev = lowpan_btle_dev(entry->netdev);
787 		peer = __peer_lookup_chan(dev, chan);
788 		if (peer) {
789 			last = peer_del(dev, peer);
790 			err = 0;
791 
792 			BT_DBG("dev %p removing %speer %p", dev,
793 			       last ? "last " : "1 ", peer);
794 			BT_DBG("chan %p orig refcnt %u", chan,
795 			       kref_read(&chan->kref));
796 
797 			l2cap_chan_put(chan);
798 			break;
799 		}
800 	}
801 
802 	if (!err && last && dev && !atomic_read(&dev->peer_count)) {
803 		spin_unlock(&devices_lock);
804 
805 		cancel_delayed_work_sync(&dev->notify_peers);
806 
807 		ifdown(dev->netdev);
808 
809 		if (remove) {
810 			INIT_WORK(&entry->delete_netdev, delete_netdev);
811 			schedule_work(&entry->delete_netdev);
812 		}
813 	} else {
814 		spin_unlock(&devices_lock);
815 	}
816 }
817 
818 static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
819 {
820 	BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
821 	       state_to_string(state), err);
822 }
823 
824 static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
825 					 unsigned long hdr_len,
826 					 unsigned long len, int nb)
827 {
828 	/* Note that we must allocate using GFP_ATOMIC here as
829 	 * this function is called originally from netdev hard xmit
830 	 * function in atomic context.
831 	 */
832 	return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
833 }
834 
835 static void chan_suspend_cb(struct l2cap_chan *chan)
836 {
837 	struct lowpan_btle_dev *dev;
838 
839 	BT_DBG("chan %p suspend", chan);
840 
841 	dev = lookup_dev(chan->conn);
842 	if (!dev || !dev->netdev)
843 		return;
844 
845 	netif_stop_queue(dev->netdev);
846 }
847 
848 static void chan_resume_cb(struct l2cap_chan *chan)
849 {
850 	struct lowpan_btle_dev *dev;
851 
852 	BT_DBG("chan %p resume", chan);
853 
854 	dev = lookup_dev(chan->conn);
855 	if (!dev || !dev->netdev)
856 		return;
857 
858 	netif_wake_queue(dev->netdev);
859 }
860 
861 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
862 {
863 	return L2CAP_CONN_TIMEOUT;
864 }
865 
866 static const struct l2cap_ops bt_6lowpan_chan_ops = {
867 	.name			= "L2CAP 6LoWPAN channel",
868 	.new_connection		= chan_new_conn_cb,
869 	.recv			= chan_recv_cb,
870 	.close			= chan_close_cb,
871 	.state_change		= chan_state_change_cb,
872 	.ready			= chan_ready_cb,
873 	.resume			= chan_resume_cb,
874 	.suspend		= chan_suspend_cb,
875 	.get_sndtimeo		= chan_get_sndtimeo_cb,
876 	.alloc_skb		= chan_alloc_skb_cb,
877 
878 	.teardown		= l2cap_chan_no_teardown,
879 	.defer			= l2cap_chan_no_defer,
880 	.set_shutdown		= l2cap_chan_no_set_shutdown,
881 };
882 
883 static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
884 {
885 	struct l2cap_chan *chan;
886 	int err;
887 
888 	chan = chan_create();
889 	if (!chan)
890 		return -EINVAL;
891 
892 	chan->ops = &bt_6lowpan_chan_ops;
893 
894 	err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
895 				 addr, dst_type);
896 
897 	BT_DBG("chan %p err %d", chan, err);
898 	if (err < 0)
899 		l2cap_chan_put(chan);
900 
901 	return err;
902 }
903 
904 static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
905 {
906 	struct lowpan_peer *peer;
907 
908 	BT_DBG("conn %p dst type %u", conn, dst_type);
909 
910 	peer = lookup_peer(conn);
911 	if (!peer)
912 		return -ENOENT;
913 
914 	BT_DBG("peer %p chan %p", peer, peer->chan);
915 
916 	l2cap_chan_close(peer->chan, ENOENT);
917 
918 	return 0;
919 }
920 
921 static struct l2cap_chan *bt_6lowpan_listen(void)
922 {
923 	bdaddr_t *addr = BDADDR_ANY;
924 	struct l2cap_chan *chan;
925 	int err;
926 
927 	if (!enable_6lowpan)
928 		return NULL;
929 
930 	chan = chan_create();
931 	if (!chan)
932 		return NULL;
933 
934 	chan->ops = &bt_6lowpan_chan_ops;
935 	chan->state = BT_LISTEN;
936 	chan->src_type = BDADDR_LE_PUBLIC;
937 
938 	atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
939 
940 	BT_DBG("chan %p src type %u", chan, chan->src_type);
941 
942 	err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
943 	if (err) {
944 		l2cap_chan_put(chan);
945 		BT_ERR("psm cannot be added err %d", err);
946 		return NULL;
947 	}
948 
949 	return chan;
950 }
951 
952 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
953 			  struct l2cap_conn **conn)
954 {
955 	struct hci_conn *hcon;
956 	struct hci_dev *hdev;
957 	int n;
958 
959 	n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
960 		   &addr->b[5], &addr->b[4], &addr->b[3],
961 		   &addr->b[2], &addr->b[1], &addr->b[0],
962 		   addr_type);
963 
964 	if (n < 7)
965 		return -EINVAL;
966 
967 	/* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
968 	hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
969 	if (!hdev)
970 		return -ENOENT;
971 
972 	hci_dev_lock(hdev);
973 	hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
974 	hci_dev_unlock(hdev);
975 
976 	if (!hcon)
977 		return -ENOENT;
978 
979 	*conn = (struct l2cap_conn *)hcon->l2cap_data;
980 
981 	BT_DBG("conn %p dst %pMR type %u", *conn, &hcon->dst, hcon->dst_type);
982 
983 	return 0;
984 }
985 
986 static void disconnect_all_peers(void)
987 {
988 	struct lowpan_btle_dev *entry;
989 	struct lowpan_peer *peer, *tmp_peer, *new_peer;
990 	struct list_head peers;
991 
992 	INIT_LIST_HEAD(&peers);
993 
994 	/* We make a separate list of peers as the close_cb() will
995 	 * modify the device peers list so it is better not to mess
996 	 * with the same list at the same time.
997 	 */
998 
999 	rcu_read_lock();
1000 
1001 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1002 		list_for_each_entry_rcu(peer, &entry->peers, list) {
1003 			new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1004 			if (!new_peer)
1005 				break;
1006 
1007 			new_peer->chan = peer->chan;
1008 			INIT_LIST_HEAD(&new_peer->list);
1009 
1010 			list_add(&new_peer->list, &peers);
1011 		}
1012 	}
1013 
1014 	rcu_read_unlock();
1015 
1016 	spin_lock(&devices_lock);
1017 	list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1018 		l2cap_chan_close(peer->chan, ENOENT);
1019 
1020 		list_del_rcu(&peer->list);
1021 		kfree_rcu(peer, rcu);
1022 	}
1023 	spin_unlock(&devices_lock);
1024 }
1025 
1026 struct set_enable {
1027 	struct work_struct work;
1028 	bool flag;
1029 };
1030 
1031 static void do_enable_set(struct work_struct *work)
1032 {
1033 	struct set_enable *set_enable = container_of(work,
1034 						     struct set_enable, work);
1035 
1036 	if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1037 		/* Disconnect existing connections if 6lowpan is
1038 		 * disabled
1039 		 */
1040 		disconnect_all_peers();
1041 
1042 	enable_6lowpan = set_enable->flag;
1043 
1044 	mutex_lock(&set_lock);
1045 	if (listen_chan) {
1046 		l2cap_chan_close(listen_chan, 0);
1047 		l2cap_chan_put(listen_chan);
1048 	}
1049 
1050 	listen_chan = bt_6lowpan_listen();
1051 	mutex_unlock(&set_lock);
1052 
1053 	kfree(set_enable);
1054 }
1055 
1056 static int lowpan_enable_set(void *data, u64 val)
1057 {
1058 	struct set_enable *set_enable;
1059 
1060 	set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1061 	if (!set_enable)
1062 		return -ENOMEM;
1063 
1064 	set_enable->flag = !!val;
1065 	INIT_WORK(&set_enable->work, do_enable_set);
1066 
1067 	schedule_work(&set_enable->work);
1068 
1069 	return 0;
1070 }
1071 
1072 static int lowpan_enable_get(void *data, u64 *val)
1073 {
1074 	*val = enable_6lowpan;
1075 	return 0;
1076 }
1077 
1078 DEFINE_DEBUGFS_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1079 			 lowpan_enable_set, "%llu\n");
1080 
1081 static ssize_t lowpan_control_write(struct file *fp,
1082 				    const char __user *user_buffer,
1083 				    size_t count,
1084 				    loff_t *position)
1085 {
1086 	char buf[32];
1087 	size_t buf_size = min(count, sizeof(buf) - 1);
1088 	int ret;
1089 	bdaddr_t addr;
1090 	u8 addr_type;
1091 	struct l2cap_conn *conn = NULL;
1092 
1093 	if (copy_from_user(buf, user_buffer, buf_size))
1094 		return -EFAULT;
1095 
1096 	buf[buf_size] = '\0';
1097 
1098 	if (memcmp(buf, "connect ", 8) == 0) {
1099 		ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1100 		if (ret == -EINVAL)
1101 			return ret;
1102 
1103 		mutex_lock(&set_lock);
1104 		if (listen_chan) {
1105 			l2cap_chan_close(listen_chan, 0);
1106 			l2cap_chan_put(listen_chan);
1107 			listen_chan = NULL;
1108 		}
1109 		mutex_unlock(&set_lock);
1110 
1111 		if (conn) {
1112 			struct lowpan_peer *peer;
1113 
1114 			if (!is_bt_6lowpan(conn->hcon))
1115 				return -EINVAL;
1116 
1117 			peer = lookup_peer(conn);
1118 			if (peer) {
1119 				BT_DBG("6LoWPAN connection already exists");
1120 				return -EALREADY;
1121 			}
1122 
1123 			BT_DBG("conn %p dst %pMR type %d user %u", conn,
1124 			       &conn->hcon->dst, conn->hcon->dst_type,
1125 			       addr_type);
1126 		}
1127 
1128 		ret = bt_6lowpan_connect(&addr, addr_type);
1129 		if (ret < 0)
1130 			return ret;
1131 
1132 		return count;
1133 	}
1134 
1135 	if (memcmp(buf, "disconnect ", 11) == 0) {
1136 		ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
1137 		if (ret < 0)
1138 			return ret;
1139 
1140 		ret = bt_6lowpan_disconnect(conn, addr_type);
1141 		if (ret < 0)
1142 			return ret;
1143 
1144 		return count;
1145 	}
1146 
1147 	return count;
1148 }
1149 
1150 static int lowpan_control_show(struct seq_file *f, void *ptr)
1151 {
1152 	struct lowpan_btle_dev *entry;
1153 	struct lowpan_peer *peer;
1154 
1155 	spin_lock(&devices_lock);
1156 
1157 	list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1158 		list_for_each_entry(peer, &entry->peers, list)
1159 			seq_printf(f, "%pMR (type %u)\n",
1160 				   &peer->chan->dst, peer->chan->dst_type);
1161 	}
1162 
1163 	spin_unlock(&devices_lock);
1164 
1165 	return 0;
1166 }
1167 
1168 static int lowpan_control_open(struct inode *inode, struct file *file)
1169 {
1170 	return single_open(file, lowpan_control_show, inode->i_private);
1171 }
1172 
1173 static const struct file_operations lowpan_control_fops = {
1174 	.open		= lowpan_control_open,
1175 	.read		= seq_read,
1176 	.write		= lowpan_control_write,
1177 	.llseek		= seq_lseek,
1178 	.release	= single_release,
1179 };
1180 
1181 static void disconnect_devices(void)
1182 {
1183 	struct lowpan_btle_dev *entry, *tmp, *new_dev;
1184 	struct list_head devices;
1185 
1186 	INIT_LIST_HEAD(&devices);
1187 
1188 	/* We make a separate list of devices because the unregister_netdev()
1189 	 * will call device_event() which will also want to modify the same
1190 	 * devices list.
1191 	 */
1192 
1193 	rcu_read_lock();
1194 
1195 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1196 		new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
1197 		if (!new_dev)
1198 			break;
1199 
1200 		new_dev->netdev = entry->netdev;
1201 		INIT_LIST_HEAD(&new_dev->list);
1202 
1203 		list_add_rcu(&new_dev->list, &devices);
1204 	}
1205 
1206 	rcu_read_unlock();
1207 
1208 	list_for_each_entry_safe(entry, tmp, &devices, list) {
1209 		ifdown(entry->netdev);
1210 		BT_DBG("Unregistering netdev %s %p",
1211 		       entry->netdev->name, entry->netdev);
1212 		lowpan_unregister_netdev(entry->netdev);
1213 		kfree(entry);
1214 	}
1215 }
1216 
1217 static int device_event(struct notifier_block *unused,
1218 			unsigned long event, void *ptr)
1219 {
1220 	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
1221 	struct lowpan_btle_dev *entry;
1222 
1223 	if (netdev->type != ARPHRD_6LOWPAN)
1224 		return NOTIFY_DONE;
1225 
1226 	switch (event) {
1227 	case NETDEV_UNREGISTER:
1228 		spin_lock(&devices_lock);
1229 		list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1230 			if (entry->netdev == netdev) {
1231 				BT_DBG("Unregistered netdev %s %p",
1232 				       netdev->name, netdev);
1233 				list_del(&entry->list);
1234 				break;
1235 			}
1236 		}
1237 		spin_unlock(&devices_lock);
1238 		break;
1239 	}
1240 
1241 	return NOTIFY_DONE;
1242 }
1243 
1244 static struct notifier_block bt_6lowpan_dev_notifier = {
1245 	.notifier_call = device_event,
1246 };
1247 
1248 static int __init bt_6lowpan_init(void)
1249 {
1250 	lowpan_enable_debugfs = debugfs_create_file_unsafe("6lowpan_enable",
1251 							   0644, bt_debugfs,
1252 							   NULL,
1253 							   &lowpan_enable_fops);
1254 	lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1255 						     bt_debugfs, NULL,
1256 						     &lowpan_control_fops);
1257 
1258 	return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1259 }
1260 
1261 static void __exit bt_6lowpan_exit(void)
1262 {
1263 	debugfs_remove(lowpan_enable_debugfs);
1264 	debugfs_remove(lowpan_control_debugfs);
1265 
1266 	if (listen_chan) {
1267 		l2cap_chan_close(listen_chan, 0);
1268 		l2cap_chan_put(listen_chan);
1269 	}
1270 
1271 	disconnect_devices();
1272 
1273 	unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1274 }
1275 
1276 module_init(bt_6lowpan_init);
1277 module_exit(bt_6lowpan_exit);
1278 
1279 MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1280 MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1281 MODULE_VERSION(VERSION);
1282 MODULE_LICENSE("GPL");
1283