xref: /openbmc/linux/net/bluetooth/6lowpan.c (revision ae213c44)
1 /*
2    Copyright (c) 2013-2014 Intel Corp.
3 
4    This program is free software; you can redistribute it and/or modify
5    it under the terms of the GNU General Public License version 2 and
6    only version 2 as published by the Free Software Foundation.
7 
8    This program is distributed in the hope that it will be useful,
9    but WITHOUT ANY WARRANTY; without even the implied warranty of
10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11    GNU General Public License for more details.
12 */
13 
14 #include <linux/if_arp.h>
15 #include <linux/netdevice.h>
16 #include <linux/etherdevice.h>
17 #include <linux/module.h>
18 #include <linux/debugfs.h>
19 
20 #include <net/ipv6.h>
21 #include <net/ip6_route.h>
22 #include <net/addrconf.h>
23 #include <net/pkt_sched.h>
24 
25 #include <net/bluetooth/bluetooth.h>
26 #include <net/bluetooth/hci_core.h>
27 #include <net/bluetooth/l2cap.h>
28 
29 #include <net/6lowpan.h> /* for the compression support */
30 
31 #define VERSION "0.1"
32 
33 static struct dentry *lowpan_enable_debugfs;
34 static struct dentry *lowpan_control_debugfs;
35 
36 #define IFACE_NAME_TEMPLATE "bt%d"
37 
38 struct skb_cb {
39 	struct in6_addr addr;
40 	struct in6_addr gw;
41 	struct l2cap_chan *chan;
42 };
43 #define lowpan_cb(skb) ((struct skb_cb *)((skb)->cb))
44 
45 /* The devices list contains those devices that we are acting
46  * as a proxy. The BT 6LoWPAN device is a virtual device that
47  * connects to the Bluetooth LE device. The real connection to
48  * BT device is done via l2cap layer. There exists one
49  * virtual device / one BT 6LoWPAN network (=hciX device).
50  * The list contains struct lowpan_dev elements.
51  */
52 static LIST_HEAD(bt_6lowpan_devices);
53 static DEFINE_SPINLOCK(devices_lock);
54 
55 static bool enable_6lowpan;
56 
57 /* We are listening incoming connections via this channel
58  */
59 static struct l2cap_chan *listen_chan;
60 
61 struct lowpan_peer {
62 	struct list_head list;
63 	struct rcu_head rcu;
64 	struct l2cap_chan *chan;
65 
66 	/* peer addresses in various formats */
67 	unsigned char lladdr[ETH_ALEN];
68 	struct in6_addr peer_addr;
69 };
70 
71 struct lowpan_btle_dev {
72 	struct list_head list;
73 
74 	struct hci_dev *hdev;
75 	struct net_device *netdev;
76 	struct list_head peers;
77 	atomic_t peer_count; /* number of items in peers list */
78 
79 	struct work_struct delete_netdev;
80 	struct delayed_work notify_peers;
81 };
82 
83 static inline struct lowpan_btle_dev *
84 lowpan_btle_dev(const struct net_device *netdev)
85 {
86 	return (struct lowpan_btle_dev *)lowpan_dev(netdev)->priv;
87 }
88 
89 static inline void peer_add(struct lowpan_btle_dev *dev,
90 			    struct lowpan_peer *peer)
91 {
92 	list_add_rcu(&peer->list, &dev->peers);
93 	atomic_inc(&dev->peer_count);
94 }
95 
96 static inline bool peer_del(struct lowpan_btle_dev *dev,
97 			    struct lowpan_peer *peer)
98 {
99 	list_del_rcu(&peer->list);
100 	kfree_rcu(peer, rcu);
101 
102 	module_put(THIS_MODULE);
103 
104 	if (atomic_dec_and_test(&dev->peer_count)) {
105 		BT_DBG("last peer");
106 		return true;
107 	}
108 
109 	return false;
110 }
111 
112 static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_btle_dev *dev,
113 						 bdaddr_t *ba, __u8 type)
114 {
115 	struct lowpan_peer *peer;
116 
117 	BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
118 	       ba, type);
119 
120 	rcu_read_lock();
121 
122 	list_for_each_entry_rcu(peer, &dev->peers, list) {
123 		BT_DBG("dst addr %pMR dst type %d",
124 		       &peer->chan->dst, peer->chan->dst_type);
125 
126 		if (bacmp(&peer->chan->dst, ba))
127 			continue;
128 
129 		if (type == peer->chan->dst_type) {
130 			rcu_read_unlock();
131 			return peer;
132 		}
133 	}
134 
135 	rcu_read_unlock();
136 
137 	return NULL;
138 }
139 
140 static inline struct lowpan_peer *
141 __peer_lookup_chan(struct lowpan_btle_dev *dev, struct l2cap_chan *chan)
142 {
143 	struct lowpan_peer *peer;
144 
145 	list_for_each_entry_rcu(peer, &dev->peers, list) {
146 		if (peer->chan == chan)
147 			return peer;
148 	}
149 
150 	return NULL;
151 }
152 
153 static inline struct lowpan_peer *
154 __peer_lookup_conn(struct lowpan_btle_dev *dev, struct l2cap_conn *conn)
155 {
156 	struct lowpan_peer *peer;
157 
158 	list_for_each_entry_rcu(peer, &dev->peers, list) {
159 		if (peer->chan->conn == conn)
160 			return peer;
161 	}
162 
163 	return NULL;
164 }
165 
166 static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_btle_dev *dev,
167 						  struct in6_addr *daddr,
168 						  struct sk_buff *skb)
169 {
170 	struct lowpan_peer *peer;
171 	struct in6_addr *nexthop;
172 	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
173 	int count = atomic_read(&dev->peer_count);
174 
175 	BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);
176 
177 	/* If we have multiple 6lowpan peers, then check where we should
178 	 * send the packet. If only one peer exists, then we can send the
179 	 * packet right away.
180 	 */
181 	if (count == 1) {
182 		rcu_read_lock();
183 		peer = list_first_or_null_rcu(&dev->peers, struct lowpan_peer,
184 					      list);
185 		rcu_read_unlock();
186 		return peer;
187 	}
188 
189 	if (!rt) {
190 		nexthop = &lowpan_cb(skb)->gw;
191 
192 		if (ipv6_addr_any(nexthop))
193 			return NULL;
194 	} else {
195 		nexthop = rt6_nexthop(rt, daddr);
196 
197 		/* We need to remember the address because it is needed
198 		 * by bt_xmit() when sending the packet. In bt_xmit(), the
199 		 * destination routing info is not set.
200 		 */
201 		memcpy(&lowpan_cb(skb)->gw, nexthop, sizeof(struct in6_addr));
202 	}
203 
204 	BT_DBG("gw %pI6c", nexthop);
205 
206 	rcu_read_lock();
207 
208 	list_for_each_entry_rcu(peer, &dev->peers, list) {
209 		BT_DBG("dst addr %pMR dst type %d ip %pI6c",
210 		       &peer->chan->dst, peer->chan->dst_type,
211 		       &peer->peer_addr);
212 
213 		if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
214 			rcu_read_unlock();
215 			return peer;
216 		}
217 	}
218 
219 	rcu_read_unlock();
220 
221 	return NULL;
222 }
223 
224 static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
225 {
226 	struct lowpan_btle_dev *entry;
227 	struct lowpan_peer *peer = NULL;
228 
229 	rcu_read_lock();
230 
231 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
232 		peer = __peer_lookup_conn(entry, conn);
233 		if (peer)
234 			break;
235 	}
236 
237 	rcu_read_unlock();
238 
239 	return peer;
240 }
241 
242 static struct lowpan_btle_dev *lookup_dev(struct l2cap_conn *conn)
243 {
244 	struct lowpan_btle_dev *entry;
245 	struct lowpan_btle_dev *dev = NULL;
246 
247 	rcu_read_lock();
248 
249 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
250 		if (conn->hcon->hdev == entry->hdev) {
251 			dev = entry;
252 			break;
253 		}
254 	}
255 
256 	rcu_read_unlock();
257 
258 	return dev;
259 }
260 
261 static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
262 {
263 	struct sk_buff *skb_cp;
264 
265 	skb_cp = skb_copy(skb, GFP_ATOMIC);
266 	if (!skb_cp)
267 		return NET_RX_DROP;
268 
269 	return netif_rx_ni(skb_cp);
270 }
271 
272 static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
273 			   struct lowpan_peer *peer)
274 {
275 	const u8 *saddr;
276 
277 	saddr = peer->lladdr;
278 
279 	return lowpan_header_decompress(skb, netdev, netdev->dev_addr, saddr);
280 }
281 
282 static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
283 		    struct lowpan_peer *peer)
284 {
285 	struct sk_buff *local_skb;
286 	int ret;
287 
288 	if (!netif_running(dev))
289 		goto drop;
290 
291 	if (dev->type != ARPHRD_6LOWPAN || !skb->len)
292 		goto drop;
293 
294 	skb_reset_network_header(skb);
295 
296 	skb = skb_share_check(skb, GFP_ATOMIC);
297 	if (!skb)
298 		goto drop;
299 
300 	/* check that it's our buffer */
301 	if (lowpan_is_ipv6(*skb_network_header(skb))) {
302 		/* Pull off the 1-byte of 6lowpan header. */
303 		skb_pull(skb, 1);
304 
305 		/* Copy the packet so that the IPv6 header is
306 		 * properly aligned.
307 		 */
308 		local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
309 					    skb_tailroom(skb), GFP_ATOMIC);
310 		if (!local_skb)
311 			goto drop;
312 
313 		local_skb->protocol = htons(ETH_P_IPV6);
314 		local_skb->pkt_type = PACKET_HOST;
315 		local_skb->dev = dev;
316 
317 		skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
318 
319 		if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
320 			kfree_skb(local_skb);
321 			goto drop;
322 		}
323 
324 		dev->stats.rx_bytes += skb->len;
325 		dev->stats.rx_packets++;
326 
327 		consume_skb(local_skb);
328 		consume_skb(skb);
329 	} else if (lowpan_is_iphc(*skb_network_header(skb))) {
330 		local_skb = skb_clone(skb, GFP_ATOMIC);
331 		if (!local_skb)
332 			goto drop;
333 
334 		local_skb->dev = dev;
335 
336 		ret = iphc_decompress(local_skb, dev, peer);
337 		if (ret < 0) {
338 			BT_DBG("iphc_decompress failed: %d", ret);
339 			kfree_skb(local_skb);
340 			goto drop;
341 		}
342 
343 		local_skb->protocol = htons(ETH_P_IPV6);
344 		local_skb->pkt_type = PACKET_HOST;
345 
346 		if (give_skb_to_upper(local_skb, dev)
347 				!= NET_RX_SUCCESS) {
348 			kfree_skb(local_skb);
349 			goto drop;
350 		}
351 
352 		dev->stats.rx_bytes += skb->len;
353 		dev->stats.rx_packets++;
354 
355 		consume_skb(local_skb);
356 		consume_skb(skb);
357 	} else {
358 		BT_DBG("unknown packet type");
359 		goto drop;
360 	}
361 
362 	return NET_RX_SUCCESS;
363 
364 drop:
365 	dev->stats.rx_dropped++;
366 	return NET_RX_DROP;
367 }
368 
369 /* Packet from BT LE device */
370 static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
371 {
372 	struct lowpan_btle_dev *dev;
373 	struct lowpan_peer *peer;
374 	int err;
375 
376 	peer = lookup_peer(chan->conn);
377 	if (!peer)
378 		return -ENOENT;
379 
380 	dev = lookup_dev(chan->conn);
381 	if (!dev || !dev->netdev)
382 		return -ENOENT;
383 
384 	err = recv_pkt(skb, dev->netdev, peer);
385 	if (err) {
386 		BT_DBG("recv pkt %d", err);
387 		err = -EAGAIN;
388 	}
389 
390 	return err;
391 }
392 
393 static int setup_header(struct sk_buff *skb, struct net_device *netdev,
394 			bdaddr_t *peer_addr, u8 *peer_addr_type)
395 {
396 	struct in6_addr ipv6_daddr;
397 	struct ipv6hdr *hdr;
398 	struct lowpan_btle_dev *dev;
399 	struct lowpan_peer *peer;
400 	u8 *daddr;
401 	int err, status = 0;
402 
403 	hdr = ipv6_hdr(skb);
404 
405 	dev = lowpan_btle_dev(netdev);
406 
407 	memcpy(&ipv6_daddr, &hdr->daddr, sizeof(ipv6_daddr));
408 
409 	if (ipv6_addr_is_multicast(&ipv6_daddr)) {
410 		lowpan_cb(skb)->chan = NULL;
411 		daddr = NULL;
412 	} else {
413 		BT_DBG("dest IP %pI6c", &ipv6_daddr);
414 
415 		/* The packet might be sent to 6lowpan interface
416 		 * because of routing (either via default route
417 		 * or user set route) so get peer according to
418 		 * the destination address.
419 		 */
420 		peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
421 		if (!peer) {
422 			BT_DBG("no such peer");
423 			return -ENOENT;
424 		}
425 
426 		daddr = peer->lladdr;
427 		*peer_addr = peer->chan->dst;
428 		*peer_addr_type = peer->chan->dst_type;
429 		lowpan_cb(skb)->chan = peer->chan;
430 
431 		status = 1;
432 	}
433 
434 	lowpan_header_compress(skb, netdev, daddr, dev->netdev->dev_addr);
435 
436 	err = dev_hard_header(skb, netdev, ETH_P_IPV6, NULL, NULL, 0);
437 	if (err < 0)
438 		return err;
439 
440 	return status;
441 }
442 
443 static int header_create(struct sk_buff *skb, struct net_device *netdev,
444 			 unsigned short type, const void *_daddr,
445 			 const void *_saddr, unsigned int len)
446 {
447 	if (type != ETH_P_IPV6)
448 		return -EINVAL;
449 
450 	return 0;
451 }
452 
453 /* Packet to BT LE device */
454 static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
455 		    struct net_device *netdev)
456 {
457 	struct msghdr msg;
458 	struct kvec iv;
459 	int err;
460 
461 	/* Remember the skb so that we can send EAGAIN to the caller if
462 	 * we run out of credits.
463 	 */
464 	chan->data = skb;
465 
466 	iv.iov_base = skb->data;
467 	iv.iov_len = skb->len;
468 
469 	memset(&msg, 0, sizeof(msg));
470 	iov_iter_kvec(&msg.msg_iter, WRITE, &iv, 1, skb->len);
471 
472 	err = l2cap_chan_send(chan, &msg, skb->len);
473 	if (err > 0) {
474 		netdev->stats.tx_bytes += err;
475 		netdev->stats.tx_packets++;
476 		return 0;
477 	}
478 
479 	if (err < 0)
480 		netdev->stats.tx_errors++;
481 
482 	return err;
483 }
484 
485 static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
486 {
487 	struct sk_buff *local_skb;
488 	struct lowpan_btle_dev *entry;
489 	int err = 0;
490 
491 	rcu_read_lock();
492 
493 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
494 		struct lowpan_peer *pentry;
495 		struct lowpan_btle_dev *dev;
496 
497 		if (entry->netdev != netdev)
498 			continue;
499 
500 		dev = lowpan_btle_dev(entry->netdev);
501 
502 		list_for_each_entry_rcu(pentry, &dev->peers, list) {
503 			int ret;
504 
505 			local_skb = skb_clone(skb, GFP_ATOMIC);
506 
507 			BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
508 			       netdev->name,
509 			       &pentry->chan->dst, pentry->chan->dst_type,
510 			       &pentry->peer_addr, pentry->chan);
511 			ret = send_pkt(pentry->chan, local_skb, netdev);
512 			if (ret < 0)
513 				err = ret;
514 
515 			kfree_skb(local_skb);
516 		}
517 	}
518 
519 	rcu_read_unlock();
520 
521 	return err;
522 }
523 
524 static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
525 {
526 	int err = 0;
527 	bdaddr_t addr;
528 	u8 addr_type;
529 
530 	/* We must take a copy of the skb before we modify/replace the ipv6
531 	 * header as the header could be used elsewhere
532 	 */
533 	skb = skb_unshare(skb, GFP_ATOMIC);
534 	if (!skb)
535 		return NET_XMIT_DROP;
536 
537 	/* Return values from setup_header()
538 	 *  <0 - error, packet is dropped
539 	 *   0 - this is a multicast packet
540 	 *   1 - this is unicast packet
541 	 */
542 	err = setup_header(skb, netdev, &addr, &addr_type);
543 	if (err < 0) {
544 		kfree_skb(skb);
545 		return NET_XMIT_DROP;
546 	}
547 
548 	if (err) {
549 		if (lowpan_cb(skb)->chan) {
550 			BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
551 			       netdev->name, &addr, addr_type,
552 			       &lowpan_cb(skb)->addr, lowpan_cb(skb)->chan);
553 			err = send_pkt(lowpan_cb(skb)->chan, skb, netdev);
554 		} else {
555 			err = -ENOENT;
556 		}
557 	} else {
558 		/* We need to send the packet to every device behind this
559 		 * interface.
560 		 */
561 		err = send_mcast_pkt(skb, netdev);
562 	}
563 
564 	dev_kfree_skb(skb);
565 
566 	if (err)
567 		BT_DBG("ERROR: xmit failed (%d)", err);
568 
569 	return err < 0 ? NET_XMIT_DROP : err;
570 }
571 
572 static int bt_dev_init(struct net_device *dev)
573 {
574 	netdev_lockdep_set_classes(dev);
575 
576 	return 0;
577 }
578 
579 static const struct net_device_ops netdev_ops = {
580 	.ndo_init		= bt_dev_init,
581 	.ndo_start_xmit		= bt_xmit,
582 };
583 
584 static struct header_ops header_ops = {
585 	.create	= header_create,
586 };
587 
588 static void netdev_setup(struct net_device *dev)
589 {
590 	dev->hard_header_len	= 0;
591 	dev->needed_tailroom	= 0;
592 	dev->flags		= IFF_RUNNING | IFF_MULTICAST;
593 	dev->watchdog_timeo	= 0;
594 	dev->tx_queue_len	= DEFAULT_TX_QUEUE_LEN;
595 
596 	dev->netdev_ops		= &netdev_ops;
597 	dev->header_ops		= &header_ops;
598 	dev->needs_free_netdev	= true;
599 }
600 
601 static struct device_type bt_type = {
602 	.name	= "bluetooth",
603 };
604 
605 static void ifup(struct net_device *netdev)
606 {
607 	int err;
608 
609 	rtnl_lock();
610 	err = dev_open(netdev, NULL);
611 	if (err < 0)
612 		BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
613 	rtnl_unlock();
614 }
615 
616 static void ifdown(struct net_device *netdev)
617 {
618 	rtnl_lock();
619 	dev_close(netdev);
620 	rtnl_unlock();
621 }
622 
623 static void do_notify_peers(struct work_struct *work)
624 {
625 	struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_dev,
626 						   notify_peers.work);
627 
628 	netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
629 }
630 
631 static bool is_bt_6lowpan(struct hci_conn *hcon)
632 {
633 	if (hcon->type != LE_LINK)
634 		return false;
635 
636 	if (!enable_6lowpan)
637 		return false;
638 
639 	return true;
640 }
641 
642 static struct l2cap_chan *chan_create(void)
643 {
644 	struct l2cap_chan *chan;
645 
646 	chan = l2cap_chan_create();
647 	if (!chan)
648 		return NULL;
649 
650 	l2cap_chan_set_defaults(chan);
651 
652 	chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
653 	chan->mode = L2CAP_MODE_LE_FLOWCTL;
654 	chan->imtu = 1280;
655 
656 	return chan;
657 }
658 
659 static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
660 					struct lowpan_btle_dev *dev,
661 					bool new_netdev)
662 {
663 	struct lowpan_peer *peer;
664 
665 	peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
666 	if (!peer)
667 		return NULL;
668 
669 	peer->chan = chan;
670 	memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
671 
672 	baswap((void *)peer->lladdr, &chan->dst);
673 
674 	lowpan_iphc_uncompress_eui48_lladdr(&peer->peer_addr, peer->lladdr);
675 
676 	spin_lock(&devices_lock);
677 	INIT_LIST_HEAD(&peer->list);
678 	peer_add(dev, peer);
679 	spin_unlock(&devices_lock);
680 
681 	/* Notifying peers about us needs to be done without locks held */
682 	if (new_netdev)
683 		INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
684 	schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
685 
686 	return peer->chan;
687 }
688 
689 static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
690 {
691 	struct net_device *netdev;
692 	int err = 0;
693 
694 	netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
695 			      IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
696 			      netdev_setup);
697 	if (!netdev)
698 		return -ENOMEM;
699 
700 	netdev->addr_assign_type = NET_ADDR_PERM;
701 	baswap((void *)netdev->dev_addr, &chan->src);
702 
703 	netdev->netdev_ops = &netdev_ops;
704 	SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
705 	SET_NETDEV_DEVTYPE(netdev, &bt_type);
706 
707 	*dev = lowpan_btle_dev(netdev);
708 	(*dev)->netdev = netdev;
709 	(*dev)->hdev = chan->conn->hcon->hdev;
710 	INIT_LIST_HEAD(&(*dev)->peers);
711 
712 	spin_lock(&devices_lock);
713 	INIT_LIST_HEAD(&(*dev)->list);
714 	list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
715 	spin_unlock(&devices_lock);
716 
717 	err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
718 	if (err < 0) {
719 		BT_INFO("register_netdev failed %d", err);
720 		spin_lock(&devices_lock);
721 		list_del_rcu(&(*dev)->list);
722 		spin_unlock(&devices_lock);
723 		free_netdev(netdev);
724 		goto out;
725 	}
726 
727 	BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
728 	       netdev->ifindex, &chan->dst, chan->dst_type,
729 	       &chan->src, chan->src_type);
730 	set_bit(__LINK_STATE_PRESENT, &netdev->state);
731 
732 	return 0;
733 
734 out:
735 	return err;
736 }
737 
738 static inline void chan_ready_cb(struct l2cap_chan *chan)
739 {
740 	struct lowpan_btle_dev *dev;
741 	bool new_netdev = false;
742 
743 	dev = lookup_dev(chan->conn);
744 
745 	BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
746 
747 	if (!dev) {
748 		if (setup_netdev(chan, &dev) < 0) {
749 			l2cap_chan_del(chan, -ENOENT);
750 			return;
751 		}
752 		new_netdev = true;
753 	}
754 
755 	if (!try_module_get(THIS_MODULE))
756 		return;
757 
758 	add_peer_chan(chan, dev, new_netdev);
759 	ifup(dev->netdev);
760 }
761 
762 static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
763 {
764 	struct l2cap_chan *chan;
765 
766 	chan = chan_create();
767 	if (!chan)
768 		return NULL;
769 
770 	chan->ops = pchan->ops;
771 
772 	BT_DBG("chan %p pchan %p", chan, pchan);
773 
774 	return chan;
775 }
776 
777 static void delete_netdev(struct work_struct *work)
778 {
779 	struct lowpan_btle_dev *entry = container_of(work,
780 						     struct lowpan_btle_dev,
781 						     delete_netdev);
782 
783 	lowpan_unregister_netdev(entry->netdev);
784 
785 	/* The entry pointer is deleted by the netdev destructor. */
786 }
787 
788 static void chan_close_cb(struct l2cap_chan *chan)
789 {
790 	struct lowpan_btle_dev *entry;
791 	struct lowpan_btle_dev *dev = NULL;
792 	struct lowpan_peer *peer;
793 	int err = -ENOENT;
794 	bool last = false, remove = true;
795 
796 	BT_DBG("chan %p conn %p", chan, chan->conn);
797 
798 	if (chan->conn && chan->conn->hcon) {
799 		if (!is_bt_6lowpan(chan->conn->hcon))
800 			return;
801 
802 		/* If conn is set, then the netdev is also there and we should
803 		 * not remove it.
804 		 */
805 		remove = false;
806 	}
807 
808 	spin_lock(&devices_lock);
809 
810 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
811 		dev = lowpan_btle_dev(entry->netdev);
812 		peer = __peer_lookup_chan(dev, chan);
813 		if (peer) {
814 			last = peer_del(dev, peer);
815 			err = 0;
816 
817 			BT_DBG("dev %p removing %speer %p", dev,
818 			       last ? "last " : "1 ", peer);
819 			BT_DBG("chan %p orig refcnt %d", chan,
820 			       kref_read(&chan->kref));
821 
822 			l2cap_chan_put(chan);
823 			break;
824 		}
825 	}
826 
827 	if (!err && last && dev && !atomic_read(&dev->peer_count)) {
828 		spin_unlock(&devices_lock);
829 
830 		cancel_delayed_work_sync(&dev->notify_peers);
831 
832 		ifdown(dev->netdev);
833 
834 		if (remove) {
835 			INIT_WORK(&entry->delete_netdev, delete_netdev);
836 			schedule_work(&entry->delete_netdev);
837 		}
838 	} else {
839 		spin_unlock(&devices_lock);
840 	}
841 
842 	return;
843 }
844 
845 static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
846 {
847 	BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
848 	       state_to_string(state), err);
849 }
850 
851 static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
852 					 unsigned long hdr_len,
853 					 unsigned long len, int nb)
854 {
855 	/* Note that we must allocate using GFP_ATOMIC here as
856 	 * this function is called originally from netdev hard xmit
857 	 * function in atomic context.
858 	 */
859 	return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
860 }
861 
862 static void chan_suspend_cb(struct l2cap_chan *chan)
863 {
864 	struct lowpan_btle_dev *dev;
865 
866 	BT_DBG("chan %p suspend", chan);
867 
868 	dev = lookup_dev(chan->conn);
869 	if (!dev || !dev->netdev)
870 		return;
871 
872 	netif_stop_queue(dev->netdev);
873 }
874 
875 static void chan_resume_cb(struct l2cap_chan *chan)
876 {
877 	struct lowpan_btle_dev *dev;
878 
879 	BT_DBG("chan %p resume", chan);
880 
881 	dev = lookup_dev(chan->conn);
882 	if (!dev || !dev->netdev)
883 		return;
884 
885 	netif_wake_queue(dev->netdev);
886 }
887 
888 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
889 {
890 	return L2CAP_CONN_TIMEOUT;
891 }
892 
893 static const struct l2cap_ops bt_6lowpan_chan_ops = {
894 	.name			= "L2CAP 6LoWPAN channel",
895 	.new_connection		= chan_new_conn_cb,
896 	.recv			= chan_recv_cb,
897 	.close			= chan_close_cb,
898 	.state_change		= chan_state_change_cb,
899 	.ready			= chan_ready_cb,
900 	.resume			= chan_resume_cb,
901 	.suspend		= chan_suspend_cb,
902 	.get_sndtimeo		= chan_get_sndtimeo_cb,
903 	.alloc_skb		= chan_alloc_skb_cb,
904 
905 	.teardown		= l2cap_chan_no_teardown,
906 	.defer			= l2cap_chan_no_defer,
907 	.set_shutdown		= l2cap_chan_no_set_shutdown,
908 };
909 
910 static inline __u8 bdaddr_type(__u8 type)
911 {
912 	if (type == ADDR_LE_DEV_PUBLIC)
913 		return BDADDR_LE_PUBLIC;
914 	else
915 		return BDADDR_LE_RANDOM;
916 }
917 
918 static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
919 {
920 	struct l2cap_chan *chan;
921 	int err;
922 
923 	chan = chan_create();
924 	if (!chan)
925 		return -EINVAL;
926 
927 	chan->ops = &bt_6lowpan_chan_ops;
928 
929 	err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
930 				 addr, dst_type);
931 
932 	BT_DBG("chan %p err %d", chan, err);
933 	if (err < 0)
934 		l2cap_chan_put(chan);
935 
936 	return err;
937 }
938 
939 static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
940 {
941 	struct lowpan_peer *peer;
942 
943 	BT_DBG("conn %p dst type %d", conn, dst_type);
944 
945 	peer = lookup_peer(conn);
946 	if (!peer)
947 		return -ENOENT;
948 
949 	BT_DBG("peer %p chan %p", peer, peer->chan);
950 
951 	l2cap_chan_close(peer->chan, ENOENT);
952 
953 	return 0;
954 }
955 
956 static struct l2cap_chan *bt_6lowpan_listen(void)
957 {
958 	bdaddr_t *addr = BDADDR_ANY;
959 	struct l2cap_chan *chan;
960 	int err;
961 
962 	if (!enable_6lowpan)
963 		return NULL;
964 
965 	chan = chan_create();
966 	if (!chan)
967 		return NULL;
968 
969 	chan->ops = &bt_6lowpan_chan_ops;
970 	chan->state = BT_LISTEN;
971 	chan->src_type = BDADDR_LE_PUBLIC;
972 
973 	atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
974 
975 	BT_DBG("chan %p src type %d", chan, chan->src_type);
976 
977 	err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
978 	if (err) {
979 		l2cap_chan_put(chan);
980 		BT_ERR("psm cannot be added err %d", err);
981 		return NULL;
982 	}
983 
984 	return chan;
985 }
986 
987 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
988 			  struct l2cap_conn **conn)
989 {
990 	struct hci_conn *hcon;
991 	struct hci_dev *hdev;
992 	int n;
993 
994 	n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
995 		   &addr->b[5], &addr->b[4], &addr->b[3],
996 		   &addr->b[2], &addr->b[1], &addr->b[0],
997 		   addr_type);
998 
999 	if (n < 7)
1000 		return -EINVAL;
1001 
1002 	/* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
1003 	hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
1004 	if (!hdev)
1005 		return -ENOENT;
1006 
1007 	hci_dev_lock(hdev);
1008 	hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
1009 	hci_dev_unlock(hdev);
1010 
1011 	if (!hcon)
1012 		return -ENOENT;
1013 
1014 	*conn = (struct l2cap_conn *)hcon->l2cap_data;
1015 
1016 	BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);
1017 
1018 	return 0;
1019 }
1020 
1021 static void disconnect_all_peers(void)
1022 {
1023 	struct lowpan_btle_dev *entry;
1024 	struct lowpan_peer *peer, *tmp_peer, *new_peer;
1025 	struct list_head peers;
1026 
1027 	INIT_LIST_HEAD(&peers);
1028 
1029 	/* We make a separate list of peers as the close_cb() will
1030 	 * modify the device peers list so it is better not to mess
1031 	 * with the same list at the same time.
1032 	 */
1033 
1034 	rcu_read_lock();
1035 
1036 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1037 		list_for_each_entry_rcu(peer, &entry->peers, list) {
1038 			new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1039 			if (!new_peer)
1040 				break;
1041 
1042 			new_peer->chan = peer->chan;
1043 			INIT_LIST_HEAD(&new_peer->list);
1044 
1045 			list_add(&new_peer->list, &peers);
1046 		}
1047 	}
1048 
1049 	rcu_read_unlock();
1050 
1051 	spin_lock(&devices_lock);
1052 	list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1053 		l2cap_chan_close(peer->chan, ENOENT);
1054 
1055 		list_del_rcu(&peer->list);
1056 		kfree_rcu(peer, rcu);
1057 	}
1058 	spin_unlock(&devices_lock);
1059 }
1060 
1061 struct set_enable {
1062 	struct work_struct work;
1063 	bool flag;
1064 };
1065 
1066 static void do_enable_set(struct work_struct *work)
1067 {
1068 	struct set_enable *set_enable = container_of(work,
1069 						     struct set_enable, work);
1070 
1071 	if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1072 		/* Disconnect existing connections if 6lowpan is
1073 		 * disabled
1074 		 */
1075 		disconnect_all_peers();
1076 
1077 	enable_6lowpan = set_enable->flag;
1078 
1079 	if (listen_chan) {
1080 		l2cap_chan_close(listen_chan, 0);
1081 		l2cap_chan_put(listen_chan);
1082 	}
1083 
1084 	listen_chan = bt_6lowpan_listen();
1085 
1086 	kfree(set_enable);
1087 }
1088 
1089 static int lowpan_enable_set(void *data, u64 val)
1090 {
1091 	struct set_enable *set_enable;
1092 
1093 	set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1094 	if (!set_enable)
1095 		return -ENOMEM;
1096 
1097 	set_enable->flag = !!val;
1098 	INIT_WORK(&set_enable->work, do_enable_set);
1099 
1100 	schedule_work(&set_enable->work);
1101 
1102 	return 0;
1103 }
1104 
1105 static int lowpan_enable_get(void *data, u64 *val)
1106 {
1107 	*val = enable_6lowpan;
1108 	return 0;
1109 }
1110 
1111 DEFINE_DEBUGFS_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1112 			 lowpan_enable_set, "%llu\n");
1113 
1114 static ssize_t lowpan_control_write(struct file *fp,
1115 				    const char __user *user_buffer,
1116 				    size_t count,
1117 				    loff_t *position)
1118 {
1119 	char buf[32];
1120 	size_t buf_size = min(count, sizeof(buf) - 1);
1121 	int ret;
1122 	bdaddr_t addr;
1123 	u8 addr_type;
1124 	struct l2cap_conn *conn = NULL;
1125 
1126 	if (copy_from_user(buf, user_buffer, buf_size))
1127 		return -EFAULT;
1128 
1129 	buf[buf_size] = '\0';
1130 
1131 	if (memcmp(buf, "connect ", 8) == 0) {
1132 		ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1133 		if (ret == -EINVAL)
1134 			return ret;
1135 
1136 		if (listen_chan) {
1137 			l2cap_chan_close(listen_chan, 0);
1138 			l2cap_chan_put(listen_chan);
1139 			listen_chan = NULL;
1140 		}
1141 
1142 		if (conn) {
1143 			struct lowpan_peer *peer;
1144 
1145 			if (!is_bt_6lowpan(conn->hcon))
1146 				return -EINVAL;
1147 
1148 			peer = lookup_peer(conn);
1149 			if (peer) {
1150 				BT_DBG("6LoWPAN connection already exists");
1151 				return -EALREADY;
1152 			}
1153 
1154 			BT_DBG("conn %p dst %pMR type %d user %d", conn,
1155 			       &conn->hcon->dst, conn->hcon->dst_type,
1156 			       addr_type);
1157 		}
1158 
1159 		ret = bt_6lowpan_connect(&addr, addr_type);
1160 		if (ret < 0)
1161 			return ret;
1162 
1163 		return count;
1164 	}
1165 
1166 	if (memcmp(buf, "disconnect ", 11) == 0) {
1167 		ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
1168 		if (ret < 0)
1169 			return ret;
1170 
1171 		ret = bt_6lowpan_disconnect(conn, addr_type);
1172 		if (ret < 0)
1173 			return ret;
1174 
1175 		return count;
1176 	}
1177 
1178 	return count;
1179 }
1180 
1181 static int lowpan_control_show(struct seq_file *f, void *ptr)
1182 {
1183 	struct lowpan_btle_dev *entry;
1184 	struct lowpan_peer *peer;
1185 
1186 	spin_lock(&devices_lock);
1187 
1188 	list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1189 		list_for_each_entry(peer, &entry->peers, list)
1190 			seq_printf(f, "%pMR (type %u)\n",
1191 				   &peer->chan->dst, peer->chan->dst_type);
1192 	}
1193 
1194 	spin_unlock(&devices_lock);
1195 
1196 	return 0;
1197 }
1198 
1199 static int lowpan_control_open(struct inode *inode, struct file *file)
1200 {
1201 	return single_open(file, lowpan_control_show, inode->i_private);
1202 }
1203 
1204 static const struct file_operations lowpan_control_fops = {
1205 	.open		= lowpan_control_open,
1206 	.read		= seq_read,
1207 	.write		= lowpan_control_write,
1208 	.llseek		= seq_lseek,
1209 	.release	= single_release,
1210 };
1211 
1212 static void disconnect_devices(void)
1213 {
1214 	struct lowpan_btle_dev *entry, *tmp, *new_dev;
1215 	struct list_head devices;
1216 
1217 	INIT_LIST_HEAD(&devices);
1218 
1219 	/* We make a separate list of devices because the unregister_netdev()
1220 	 * will call device_event() which will also want to modify the same
1221 	 * devices list.
1222 	 */
1223 
1224 	rcu_read_lock();
1225 
1226 	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1227 		new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
1228 		if (!new_dev)
1229 			break;
1230 
1231 		new_dev->netdev = entry->netdev;
1232 		INIT_LIST_HEAD(&new_dev->list);
1233 
1234 		list_add_rcu(&new_dev->list, &devices);
1235 	}
1236 
1237 	rcu_read_unlock();
1238 
1239 	list_for_each_entry_safe(entry, tmp, &devices, list) {
1240 		ifdown(entry->netdev);
1241 		BT_DBG("Unregistering netdev %s %p",
1242 		       entry->netdev->name, entry->netdev);
1243 		lowpan_unregister_netdev(entry->netdev);
1244 		kfree(entry);
1245 	}
1246 }
1247 
1248 static int device_event(struct notifier_block *unused,
1249 			unsigned long event, void *ptr)
1250 {
1251 	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
1252 	struct lowpan_btle_dev *entry;
1253 
1254 	if (netdev->type != ARPHRD_6LOWPAN)
1255 		return NOTIFY_DONE;
1256 
1257 	switch (event) {
1258 	case NETDEV_UNREGISTER:
1259 		spin_lock(&devices_lock);
1260 		list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1261 			if (entry->netdev == netdev) {
1262 				BT_DBG("Unregistered netdev %s %p",
1263 				       netdev->name, netdev);
1264 				list_del(&entry->list);
1265 				break;
1266 			}
1267 		}
1268 		spin_unlock(&devices_lock);
1269 		break;
1270 	}
1271 
1272 	return NOTIFY_DONE;
1273 }
1274 
1275 static struct notifier_block bt_6lowpan_dev_notifier = {
1276 	.notifier_call = device_event,
1277 };
1278 
1279 static int __init bt_6lowpan_init(void)
1280 {
1281 	lowpan_enable_debugfs = debugfs_create_file_unsafe("6lowpan_enable",
1282 							   0644, bt_debugfs,
1283 							   NULL,
1284 							   &lowpan_enable_fops);
1285 	lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1286 						     bt_debugfs, NULL,
1287 						     &lowpan_control_fops);
1288 
1289 	return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1290 }
1291 
1292 static void __exit bt_6lowpan_exit(void)
1293 {
1294 	debugfs_remove(lowpan_enable_debugfs);
1295 	debugfs_remove(lowpan_control_debugfs);
1296 
1297 	if (listen_chan) {
1298 		l2cap_chan_close(listen_chan, 0);
1299 		l2cap_chan_put(listen_chan);
1300 	}
1301 
1302 	disconnect_devices();
1303 
1304 	unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1305 }
1306 
1307 module_init(bt_6lowpan_init);
1308 module_exit(bt_6lowpan_exit);
1309 
1310 MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1311 MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1312 MODULE_VERSION(VERSION);
1313 MODULE_LICENSE("GPL");
1314