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TOMOYO Linux Cross Reference
Linux/net/bluetooth/6lowpan.c

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  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         struct lowpan_btle_dev *dev;
277 
278         dev = lowpan_btle_dev(netdev);
279 
280         saddr = peer->lladdr;
281 
282         return lowpan_header_decompress(skb, netdev, netdev->dev_addr, saddr);
283 }
284 
285 static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
286                     struct lowpan_peer *peer)
287 {
288         struct sk_buff *local_skb;
289         int ret;
290 
291         if (!netif_running(dev))
292                 goto drop;
293 
294         if (dev->type != ARPHRD_6LOWPAN || !skb->len)
295                 goto drop;
296 
297         skb_reset_network_header(skb);
298 
299         skb = skb_share_check(skb, GFP_ATOMIC);
300         if (!skb)
301                 goto drop;
302 
303         /* check that it's our buffer */
304         if (lowpan_is_ipv6(*skb_network_header(skb))) {
305                 /* Pull off the 1-byte of 6lowpan header. */
306                 skb_pull(skb, 1);
307 
308                 /* Copy the packet so that the IPv6 header is
309                  * properly aligned.
310                  */
311                 local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
312                                             skb_tailroom(skb), GFP_ATOMIC);
313                 if (!local_skb)
314                         goto drop;
315 
316                 local_skb->protocol = htons(ETH_P_IPV6);
317                 local_skb->pkt_type = PACKET_HOST;
318                 local_skb->dev = dev;
319 
320                 skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
321 
322                 if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
323                         kfree_skb(local_skb);
324                         goto drop;
325                 }
326 
327                 dev->stats.rx_bytes += skb->len;
328                 dev->stats.rx_packets++;
329 
330                 consume_skb(local_skb);
331                 consume_skb(skb);
332         } else if (lowpan_is_iphc(*skb_network_header(skb))) {
333                 local_skb = skb_clone(skb, GFP_ATOMIC);
334                 if (!local_skb)
335                         goto drop;
336 
337                 local_skb->dev = dev;
338 
339                 ret = iphc_decompress(local_skb, dev, peer);
340                 if (ret < 0) {
341                         BT_DBG("iphc_decompress failed: %d", ret);
342                         kfree_skb(local_skb);
343                         goto drop;
344                 }
345 
346                 local_skb->protocol = htons(ETH_P_IPV6);
347                 local_skb->pkt_type = PACKET_HOST;
348 
349                 if (give_skb_to_upper(local_skb, dev)
350                                 != NET_RX_SUCCESS) {
351                         kfree_skb(local_skb);
352                         goto drop;
353                 }
354 
355                 dev->stats.rx_bytes += skb->len;
356                 dev->stats.rx_packets++;
357 
358                 consume_skb(local_skb);
359                 consume_skb(skb);
360         } else {
361                 BT_DBG("unknown packet type");
362                 goto drop;
363         }
364 
365         return NET_RX_SUCCESS;
366 
367 drop:
368         dev->stats.rx_dropped++;
369         return NET_RX_DROP;
370 }
371 
372 /* Packet from BT LE device */
373 static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
374 {
375         struct lowpan_btle_dev *dev;
376         struct lowpan_peer *peer;
377         int err;
378 
379         peer = lookup_peer(chan->conn);
380         if (!peer)
381                 return -ENOENT;
382 
383         dev = lookup_dev(chan->conn);
384         if (!dev || !dev->netdev)
385                 return -ENOENT;
386 
387         err = recv_pkt(skb, dev->netdev, peer);
388         if (err) {
389                 BT_DBG("recv pkt %d", err);
390                 err = -EAGAIN;
391         }
392 
393         return err;
394 }
395 
396 static int setup_header(struct sk_buff *skb, struct net_device *netdev,
397                         bdaddr_t *peer_addr, u8 *peer_addr_type)
398 {
399         struct in6_addr ipv6_daddr;
400         struct ipv6hdr *hdr;
401         struct lowpan_btle_dev *dev;
402         struct lowpan_peer *peer;
403         u8 *daddr;
404         int err, status = 0;
405 
406         hdr = ipv6_hdr(skb);
407 
408         dev = lowpan_btle_dev(netdev);
409 
410         memcpy(&ipv6_daddr, &hdr->daddr, sizeof(ipv6_daddr));
411 
412         if (ipv6_addr_is_multicast(&ipv6_daddr)) {
413                 lowpan_cb(skb)->chan = NULL;
414                 daddr = NULL;
415         } else {
416                 BT_DBG("dest IP %pI6c", &ipv6_daddr);
417 
418                 /* The packet might be sent to 6lowpan interface
419                  * because of routing (either via default route
420                  * or user set route) so get peer according to
421                  * the destination address.
422                  */
423                 peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
424                 if (!peer) {
425                         BT_DBG("no such peer");
426                         return -ENOENT;
427                 }
428 
429                 daddr = peer->lladdr;
430                 *peer_addr = peer->chan->dst;
431                 *peer_addr_type = peer->chan->dst_type;
432                 lowpan_cb(skb)->chan = peer->chan;
433 
434                 status = 1;
435         }
436 
437         lowpan_header_compress(skb, netdev, daddr, dev->netdev->dev_addr);
438 
439         err = dev_hard_header(skb, netdev, ETH_P_IPV6, NULL, NULL, 0);
440         if (err < 0)
441                 return err;
442 
443         return status;
444 }
445 
446 static int header_create(struct sk_buff *skb, struct net_device *netdev,
447                          unsigned short type, const void *_daddr,
448                          const void *_saddr, unsigned int len)
449 {
450         if (type != ETH_P_IPV6)
451                 return -EINVAL;
452 
453         return 0;
454 }
455 
456 /* Packet to BT LE device */
457 static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
458                     struct net_device *netdev)
459 {
460         struct msghdr msg;
461         struct kvec iv;
462         int err;
463 
464         /* Remember the skb so that we can send EAGAIN to the caller if
465          * we run out of credits.
466          */
467         chan->data = skb;
468 
469         iv.iov_base = skb->data;
470         iv.iov_len = skb->len;
471 
472         memset(&msg, 0, sizeof(msg));
473         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, &iv, 1, skb->len);
474 
475         err = l2cap_chan_send(chan, &msg, skb->len);
476         if (err > 0) {
477                 netdev->stats.tx_bytes += err;
478                 netdev->stats.tx_packets++;
479                 return 0;
480         }
481 
482         if (err < 0)
483                 netdev->stats.tx_errors++;
484 
485         return err;
486 }
487 
488 static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
489 {
490         struct sk_buff *local_skb;
491         struct lowpan_btle_dev *entry;
492         int err = 0;
493 
494         rcu_read_lock();
495 
496         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
497                 struct lowpan_peer *pentry;
498                 struct lowpan_btle_dev *dev;
499 
500                 if (entry->netdev != netdev)
501                         continue;
502 
503                 dev = lowpan_btle_dev(entry->netdev);
504 
505                 list_for_each_entry_rcu(pentry, &dev->peers, list) {
506                         int ret;
507 
508                         local_skb = skb_clone(skb, GFP_ATOMIC);
509 
510                         BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
511                                netdev->name,
512                                &pentry->chan->dst, pentry->chan->dst_type,
513                                &pentry->peer_addr, pentry->chan);
514                         ret = send_pkt(pentry->chan, local_skb, netdev);
515                         if (ret < 0)
516                                 err = ret;
517 
518                         kfree_skb(local_skb);
519                 }
520         }
521 
522         rcu_read_unlock();
523 
524         return err;
525 }
526 
527 static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
528 {
529         int err = 0;
530         bdaddr_t addr;
531         u8 addr_type;
532 
533         /* We must take a copy of the skb before we modify/replace the ipv6
534          * header as the header could be used elsewhere
535          */
536         skb = skb_unshare(skb, GFP_ATOMIC);
537         if (!skb)
538                 return NET_XMIT_DROP;
539 
540         /* Return values from setup_header()
541          *  <0 - error, packet is dropped
542          *   0 - this is a multicast packet
543          *   1 - this is unicast packet
544          */
545         err = setup_header(skb, netdev, &addr, &addr_type);
546         if (err < 0) {
547                 kfree_skb(skb);
548                 return NET_XMIT_DROP;
549         }
550 
551         if (err) {
552                 if (lowpan_cb(skb)->chan) {
553                         BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
554                                netdev->name, &addr, addr_type,
555                                &lowpan_cb(skb)->addr, lowpan_cb(skb)->chan);
556                         err = send_pkt(lowpan_cb(skb)->chan, skb, netdev);
557                 } else {
558                         err = -ENOENT;
559                 }
560         } else {
561                 /* We need to send the packet to every device behind this
562                  * interface.
563                  */
564                 err = send_mcast_pkt(skb, netdev);
565         }
566 
567         dev_kfree_skb(skb);
568 
569         if (err)
570                 BT_DBG("ERROR: xmit failed (%d)", err);
571 
572         return err < 0 ? NET_XMIT_DROP : err;
573 }
574 
575 static int bt_dev_init(struct net_device *dev)
576 {
577         netdev_lockdep_set_classes(dev);
578 
579         return 0;
580 }
581 
582 static const struct net_device_ops netdev_ops = {
583         .ndo_init               = bt_dev_init,
584         .ndo_start_xmit         = bt_xmit,
585 };
586 
587 static struct header_ops header_ops = {
588         .create = header_create,
589 };
590 
591 static void netdev_setup(struct net_device *dev)
592 {
593         dev->hard_header_len    = 0;
594         dev->needed_tailroom    = 0;
595         dev->flags              = IFF_RUNNING | IFF_MULTICAST;
596         dev->watchdog_timeo     = 0;
597         dev->tx_queue_len       = DEFAULT_TX_QUEUE_LEN;
598 
599         dev->netdev_ops         = &netdev_ops;
600         dev->header_ops         = &header_ops;
601         dev->needs_free_netdev  = true;
602 }
603 
604 static struct device_type bt_type = {
605         .name   = "bluetooth",
606 };
607 
608 static void ifup(struct net_device *netdev)
609 {
610         int err;
611 
612         rtnl_lock();
613         err = dev_open(netdev);
614         if (err < 0)
615                 BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
616         rtnl_unlock();
617 }
618 
619 static void ifdown(struct net_device *netdev)
620 {
621         int err;
622 
623         rtnl_lock();
624         err = dev_close(netdev);
625         if (err < 0)
626                 BT_INFO("iface %s cannot be closed (%d)", netdev->name, err);
627         rtnl_unlock();
628 }
629 
630 static void do_notify_peers(struct work_struct *work)
631 {
632         struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_dev,
633                                                    notify_peers.work);
634 
635         netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
636 }
637 
638 static bool is_bt_6lowpan(struct hci_conn *hcon)
639 {
640         if (hcon->type != LE_LINK)
641                 return false;
642 
643         if (!enable_6lowpan)
644                 return false;
645 
646         return true;
647 }
648 
649 static struct l2cap_chan *chan_create(void)
650 {
651         struct l2cap_chan *chan;
652 
653         chan = l2cap_chan_create();
654         if (!chan)
655                 return NULL;
656 
657         l2cap_chan_set_defaults(chan);
658 
659         chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
660         chan->mode = L2CAP_MODE_LE_FLOWCTL;
661         chan->imtu = 1280;
662 
663         return chan;
664 }
665 
666 static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
667                                         struct lowpan_btle_dev *dev,
668                                         bool new_netdev)
669 {
670         struct lowpan_peer *peer;
671 
672         peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
673         if (!peer)
674                 return NULL;
675 
676         peer->chan = chan;
677         memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
678 
679         baswap((void *)peer->lladdr, &chan->dst);
680 
681         lowpan_iphc_uncompress_eui48_lladdr(&peer->peer_addr, peer->lladdr);
682 
683         spin_lock(&devices_lock);
684         INIT_LIST_HEAD(&peer->list);
685         peer_add(dev, peer);
686         spin_unlock(&devices_lock);
687 
688         /* Notifying peers about us needs to be done without locks held */
689         if (new_netdev)
690                 INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
691         schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
692 
693         return peer->chan;
694 }
695 
696 static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
697 {
698         struct net_device *netdev;
699         int err = 0;
700 
701         netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
702                               IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
703                               netdev_setup);
704         if (!netdev)
705                 return -ENOMEM;
706 
707         netdev->addr_assign_type = NET_ADDR_PERM;
708         baswap((void *)netdev->dev_addr, &chan->src);
709 
710         netdev->netdev_ops = &netdev_ops;
711         SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
712         SET_NETDEV_DEVTYPE(netdev, &bt_type);
713 
714         *dev = lowpan_btle_dev(netdev);
715         (*dev)->netdev = netdev;
716         (*dev)->hdev = chan->conn->hcon->hdev;
717         INIT_LIST_HEAD(&(*dev)->peers);
718 
719         spin_lock(&devices_lock);
720         INIT_LIST_HEAD(&(*dev)->list);
721         list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
722         spin_unlock(&devices_lock);
723 
724         err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
725         if (err < 0) {
726                 BT_INFO("register_netdev failed %d", err);
727                 spin_lock(&devices_lock);
728                 list_del_rcu(&(*dev)->list);
729                 spin_unlock(&devices_lock);
730                 free_netdev(netdev);
731                 goto out;
732         }
733 
734         BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
735                netdev->ifindex, &chan->dst, chan->dst_type,
736                &chan->src, chan->src_type);
737         set_bit(__LINK_STATE_PRESENT, &netdev->state);
738 
739         return 0;
740 
741 out:
742         return err;
743 }
744 
745 static inline void chan_ready_cb(struct l2cap_chan *chan)
746 {
747         struct lowpan_btle_dev *dev;
748         bool new_netdev = false;
749 
750         dev = lookup_dev(chan->conn);
751 
752         BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
753 
754         if (!dev) {
755                 if (setup_netdev(chan, &dev) < 0) {
756                         l2cap_chan_del(chan, -ENOENT);
757                         return;
758                 }
759                 new_netdev = true;
760         }
761 
762         if (!try_module_get(THIS_MODULE))
763                 return;
764 
765         add_peer_chan(chan, dev, new_netdev);
766         ifup(dev->netdev);
767 }
768 
769 static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
770 {
771         struct l2cap_chan *chan;
772 
773         chan = chan_create();
774         if (!chan)
775                 return NULL;
776 
777         chan->ops = pchan->ops;
778 
779         BT_DBG("chan %p pchan %p", chan, pchan);
780 
781         return chan;
782 }
783 
784 static void delete_netdev(struct work_struct *work)
785 {
786         struct lowpan_btle_dev *entry = container_of(work,
787                                                      struct lowpan_btle_dev,
788                                                      delete_netdev);
789 
790         lowpan_unregister_netdev(entry->netdev);
791 
792         /* The entry pointer is deleted by the netdev destructor. */
793 }
794 
795 static void chan_close_cb(struct l2cap_chan *chan)
796 {
797         struct lowpan_btle_dev *entry;
798         struct lowpan_btle_dev *dev = NULL;
799         struct lowpan_peer *peer;
800         int err = -ENOENT;
801         bool last = false, remove = true;
802 
803         BT_DBG("chan %p conn %p", chan, chan->conn);
804 
805         if (chan->conn && chan->conn->hcon) {
806                 if (!is_bt_6lowpan(chan->conn->hcon))
807                         return;
808 
809                 /* If conn is set, then the netdev is also there and we should
810                  * not remove it.
811                  */
812                 remove = false;
813         }
814 
815         spin_lock(&devices_lock);
816 
817         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
818                 dev = lowpan_btle_dev(entry->netdev);
819                 peer = __peer_lookup_chan(dev, chan);
820                 if (peer) {
821                         last = peer_del(dev, peer);
822                         err = 0;
823 
824                         BT_DBG("dev %p removing %speer %p", dev,
825                                last ? "last " : "1 ", peer);
826                         BT_DBG("chan %p orig refcnt %d", chan,
827                                kref_read(&chan->kref));
828 
829                         l2cap_chan_put(chan);
830                         break;
831                 }
832         }
833 
834         if (!err && last && dev && !atomic_read(&dev->peer_count)) {
835                 spin_unlock(&devices_lock);
836 
837                 cancel_delayed_work_sync(&dev->notify_peers);
838 
839                 ifdown(dev->netdev);
840 
841                 if (remove) {
842                         INIT_WORK(&entry->delete_netdev, delete_netdev);
843                         schedule_work(&entry->delete_netdev);
844                 }
845         } else {
846                 spin_unlock(&devices_lock);
847         }
848 
849         return;
850 }
851 
852 static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
853 {
854         BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
855                state_to_string(state), err);
856 }
857 
858 static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
859                                          unsigned long hdr_len,
860                                          unsigned long len, int nb)
861 {
862         /* Note that we must allocate using GFP_ATOMIC here as
863          * this function is called originally from netdev hard xmit
864          * function in atomic context.
865          */
866         return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
867 }
868 
869 static void chan_suspend_cb(struct l2cap_chan *chan)
870 {
871         struct lowpan_btle_dev *dev;
872 
873         BT_DBG("chan %p suspend", chan);
874 
875         dev = lookup_dev(chan->conn);
876         if (!dev || !dev->netdev)
877                 return;
878 
879         netif_stop_queue(dev->netdev);
880 }
881 
882 static void chan_resume_cb(struct l2cap_chan *chan)
883 {
884         struct lowpan_btle_dev *dev;
885 
886         BT_DBG("chan %p resume", chan);
887 
888         dev = lookup_dev(chan->conn);
889         if (!dev || !dev->netdev)
890                 return;
891 
892         netif_wake_queue(dev->netdev);
893 }
894 
895 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
896 {
897         return L2CAP_CONN_TIMEOUT;
898 }
899 
900 static const struct l2cap_ops bt_6lowpan_chan_ops = {
901         .name                   = "L2CAP 6LoWPAN channel",
902         .new_connection         = chan_new_conn_cb,
903         .recv                   = chan_recv_cb,
904         .close                  = chan_close_cb,
905         .state_change           = chan_state_change_cb,
906         .ready                  = chan_ready_cb,
907         .resume                 = chan_resume_cb,
908         .suspend                = chan_suspend_cb,
909         .get_sndtimeo           = chan_get_sndtimeo_cb,
910         .alloc_skb              = chan_alloc_skb_cb,
911 
912         .teardown               = l2cap_chan_no_teardown,
913         .defer                  = l2cap_chan_no_defer,
914         .set_shutdown           = l2cap_chan_no_set_shutdown,
915 };
916 
917 static inline __u8 bdaddr_type(__u8 type)
918 {
919         if (type == ADDR_LE_DEV_PUBLIC)
920                 return BDADDR_LE_PUBLIC;
921         else
922                 return BDADDR_LE_RANDOM;
923 }
924 
925 static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
926 {
927         struct l2cap_chan *chan;
928         int err;
929 
930         chan = chan_create();
931         if (!chan)
932                 return -EINVAL;
933 
934         chan->ops = &bt_6lowpan_chan_ops;
935 
936         err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
937                                  addr, dst_type);
938 
939         BT_DBG("chan %p err %d", chan, err);
940         if (err < 0)
941                 l2cap_chan_put(chan);
942 
943         return err;
944 }
945 
946 static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
947 {
948         struct lowpan_peer *peer;
949 
950         BT_DBG("conn %p dst type %d", conn, dst_type);
951 
952         peer = lookup_peer(conn);
953         if (!peer)
954                 return -ENOENT;
955 
956         BT_DBG("peer %p chan %p", peer, peer->chan);
957 
958         l2cap_chan_close(peer->chan, ENOENT);
959 
960         return 0;
961 }
962 
963 static struct l2cap_chan *bt_6lowpan_listen(void)
964 {
965         bdaddr_t *addr = BDADDR_ANY;
966         struct l2cap_chan *chan;
967         int err;
968 
969         if (!enable_6lowpan)
970                 return NULL;
971 
972         chan = chan_create();
973         if (!chan)
974                 return NULL;
975 
976         chan->ops = &bt_6lowpan_chan_ops;
977         chan->state = BT_LISTEN;
978         chan->src_type = BDADDR_LE_PUBLIC;
979 
980         atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
981 
982         BT_DBG("chan %p src type %d", chan, chan->src_type);
983 
984         err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
985         if (err) {
986                 l2cap_chan_put(chan);
987                 BT_ERR("psm cannot be added err %d", err);
988                 return NULL;
989         }
990 
991         return chan;
992 }
993 
994 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
995                           struct l2cap_conn **conn)
996 {
997         struct hci_conn *hcon;
998         struct hci_dev *hdev;
999         int n;
1000 
1001         n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
1002                    &addr->b[5], &addr->b[4], &addr->b[3],
1003                    &addr->b[2], &addr->b[1], &addr->b[0],
1004                    addr_type);
1005 
1006         if (n < 7)
1007                 return -EINVAL;
1008 
1009         /* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
1010         hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
1011         if (!hdev)
1012                 return -ENOENT;
1013 
1014         hci_dev_lock(hdev);
1015         hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
1016         hci_dev_unlock(hdev);
1017 
1018         if (!hcon)
1019                 return -ENOENT;
1020 
1021         *conn = (struct l2cap_conn *)hcon->l2cap_data;
1022 
1023         BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);
1024 
1025         return 0;
1026 }
1027 
1028 static void disconnect_all_peers(void)
1029 {
1030         struct lowpan_btle_dev *entry;
1031         struct lowpan_peer *peer, *tmp_peer, *new_peer;
1032         struct list_head peers;
1033 
1034         INIT_LIST_HEAD(&peers);
1035 
1036         /* We make a separate list of peers as the close_cb() will
1037          * modify the device peers list so it is better not to mess
1038          * with the same list at the same time.
1039          */
1040 
1041         rcu_read_lock();
1042 
1043         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1044                 list_for_each_entry_rcu(peer, &entry->peers, list) {
1045                         new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1046                         if (!new_peer)
1047                                 break;
1048 
1049                         new_peer->chan = peer->chan;
1050                         INIT_LIST_HEAD(&new_peer->list);
1051 
1052                         list_add(&new_peer->list, &peers);
1053                 }
1054         }
1055 
1056         rcu_read_unlock();
1057 
1058         spin_lock(&devices_lock);
1059         list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1060                 l2cap_chan_close(peer->chan, ENOENT);
1061 
1062                 list_del_rcu(&peer->list);
1063                 kfree_rcu(peer, rcu);
1064         }
1065         spin_unlock(&devices_lock);
1066 }
1067 
1068 struct set_enable {
1069         struct work_struct work;
1070         bool flag;
1071 };
1072 
1073 static void do_enable_set(struct work_struct *work)
1074 {
1075         struct set_enable *set_enable = container_of(work,
1076                                                      struct set_enable, work);
1077 
1078         if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1079                 /* Disconnect existing connections if 6lowpan is
1080                  * disabled
1081                  */
1082                 disconnect_all_peers();
1083 
1084         enable_6lowpan = set_enable->flag;
1085 
1086         if (listen_chan) {
1087                 l2cap_chan_close(listen_chan, 0);
1088                 l2cap_chan_put(listen_chan);
1089         }
1090 
1091         listen_chan = bt_6lowpan_listen();
1092 
1093         kfree(set_enable);
1094 }
1095 
1096 static int lowpan_enable_set(void *data, u64 val)
1097 {
1098         struct set_enable *set_enable;
1099 
1100         set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1101         if (!set_enable)
1102                 return -ENOMEM;
1103 
1104         set_enable->flag = !!val;
1105         INIT_WORK(&set_enable->work, do_enable_set);
1106 
1107         schedule_work(&set_enable->work);
1108 
1109         return 0;
1110 }
1111 
1112 static int lowpan_enable_get(void *data, u64 *val)
1113 {
1114         *val = enable_6lowpan;
1115         return 0;
1116 }
1117 
1118 DEFINE_SIMPLE_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1119                         lowpan_enable_set, "%llu\n");
1120 
1121 static ssize_t lowpan_control_write(struct file *fp,
1122                                     const char __user *user_buffer,
1123                                     size_t count,
1124                                     loff_t *position)
1125 {
1126         char buf[32];
1127         size_t buf_size = min(count, sizeof(buf) - 1);
1128         int ret;
1129         bdaddr_t addr;
1130         u8 addr_type;
1131         struct l2cap_conn *conn = NULL;
1132 
1133         if (copy_from_user(buf, user_buffer, buf_size))
1134                 return -EFAULT;
1135 
1136         buf[buf_size] = '\0';
1137 
1138         if (memcmp(buf, "connect ", 8) == 0) {
1139                 ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1140                 if (ret == -EINVAL)
1141                         return ret;
1142 
1143                 if (listen_chan) {
1144                         l2cap_chan_close(listen_chan, 0);
1145                         l2cap_chan_put(listen_chan);
1146                         listen_chan = NULL;
1147                 }
1148 
1149                 if (conn) {
1150                         struct lowpan_peer *peer;
1151 
1152                         if (!is_bt_6lowpan(conn->hcon))
1153                                 return -EINVAL;
1154 
1155                         peer = lookup_peer(conn);
1156                         if (peer) {
1157                                 BT_DBG("6LoWPAN connection already exists");
1158                                 return -EALREADY;
1159                         }
1160 
1161                         BT_DBG("conn %p dst %pMR type %d user %d", conn,
1162                                &conn->hcon->dst, conn->hcon->dst_type,
1163                                addr_type);
1164                 }
1165 
1166                 ret = bt_6lowpan_connect(&addr, addr_type);
1167                 if (ret < 0)
1168                         return ret;
1169 
1170                 return count;
1171         }
1172 
1173         if (memcmp(buf, "disconnect ", 11) == 0) {
1174                 ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
1175                 if (ret < 0)
1176                         return ret;
1177 
1178                 ret = bt_6lowpan_disconnect(conn, addr_type);
1179                 if (ret < 0)
1180                         return ret;
1181 
1182                 return count;
1183         }
1184 
1185         return count;
1186 }
1187 
1188 static int lowpan_control_show(struct seq_file *f, void *ptr)
1189 {
1190         struct lowpan_btle_dev *entry;
1191         struct lowpan_peer *peer;
1192 
1193         spin_lock(&devices_lock);
1194 
1195         list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1196                 list_for_each_entry(peer, &entry->peers, list)
1197                         seq_printf(f, "%pMR (type %u)\n",
1198                                    &peer->chan->dst, peer->chan->dst_type);
1199         }
1200 
1201         spin_unlock(&devices_lock);
1202 
1203         return 0;
1204 }
1205 
1206 static int lowpan_control_open(struct inode *inode, struct file *file)
1207 {
1208         return single_open(file, lowpan_control_show, inode->i_private);
1209 }
1210 
1211 static const struct file_operations lowpan_control_fops = {
1212         .open           = lowpan_control_open,
1213         .read           = seq_read,
1214         .write          = lowpan_control_write,
1215         .llseek         = seq_lseek,
1216         .release        = single_release,
1217 };
1218 
1219 static void disconnect_devices(void)
1220 {
1221         struct lowpan_btle_dev *entry, *tmp, *new_dev;
1222         struct list_head devices;
1223 
1224         INIT_LIST_HEAD(&devices);
1225 
1226         /* We make a separate list of devices because the unregister_netdev()
1227          * will call device_event() which will also want to modify the same
1228          * devices list.
1229          */
1230 
1231         rcu_read_lock();
1232 
1233         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1234                 new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
1235                 if (!new_dev)
1236                         break;
1237 
1238                 new_dev->netdev = entry->netdev;
1239                 INIT_LIST_HEAD(&new_dev->list);
1240 
1241                 list_add_rcu(&new_dev->list, &devices);
1242         }
1243 
1244         rcu_read_unlock();
1245 
1246         list_for_each_entry_safe(entry, tmp, &devices, list) {
1247                 ifdown(entry->netdev);
1248                 BT_DBG("Unregistering netdev %s %p",
1249                        entry->netdev->name, entry->netdev);
1250                 lowpan_unregister_netdev(entry->netdev);
1251                 kfree(entry);
1252         }
1253 }
1254 
1255 static int device_event(struct notifier_block *unused,
1256                         unsigned long event, void *ptr)
1257 {
1258         struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
1259         struct lowpan_btle_dev *entry;
1260 
1261         if (netdev->type != ARPHRD_6LOWPAN)
1262                 return NOTIFY_DONE;
1263 
1264         switch (event) {
1265         case NETDEV_UNREGISTER:
1266                 spin_lock(&devices_lock);
1267                 list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1268                         if (entry->netdev == netdev) {
1269                                 BT_DBG("Unregistered netdev %s %p",
1270                                        netdev->name, netdev);
1271                                 list_del(&entry->list);
1272                                 break;
1273                         }
1274                 }
1275                 spin_unlock(&devices_lock);
1276                 break;
1277         }
1278 
1279         return NOTIFY_DONE;
1280 }
1281 
1282 static struct notifier_block bt_6lowpan_dev_notifier = {
1283         .notifier_call = device_event,
1284 };
1285 
1286 static int __init bt_6lowpan_init(void)
1287 {
1288         lowpan_enable_debugfs = debugfs_create_file("6lowpan_enable", 0644,
1289                                                     bt_debugfs, NULL,
1290                                                     &lowpan_enable_fops);
1291         lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1292                                                      bt_debugfs, NULL,
1293                                                      &lowpan_control_fops);
1294 
1295         return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1296 }
1297 
1298 static void __exit bt_6lowpan_exit(void)
1299 {
1300         debugfs_remove(lowpan_enable_debugfs);
1301         debugfs_remove(lowpan_control_debugfs);
1302 
1303         if (listen_chan) {
1304                 l2cap_chan_close(listen_chan, 0);
1305                 l2cap_chan_put(listen_chan);
1306         }
1307 
1308         disconnect_devices();
1309 
1310         unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1311 }
1312 
1313 module_init(bt_6lowpan_init);
1314 module_exit(bt_6lowpan_exit);
1315 
1316 MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1317 MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1318 MODULE_VERSION(VERSION);
1319 MODULE_LICENSE("GPL");
1320 

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