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

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  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 *peer_lookup_ba(struct lowpan_btle_dev *dev,
107                                                  bdaddr_t *ba, __u8 type)
108 {
109         struct lowpan_peer *peer;
110 
111         BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
112                ba, type);
113 
114         rcu_read_lock();
115 
116         list_for_each_entry_rcu(peer, &dev->peers, list) {
117                 BT_DBG("dst addr %pMR dst type %d",
118                        &peer->chan->dst, peer->chan->dst_type);
119 
120                 if (bacmp(&peer->chan->dst, ba))
121                         continue;
122 
123                 if (type == peer->chan->dst_type) {
124                         rcu_read_unlock();
125                         return peer;
126                 }
127         }
128 
129         rcu_read_unlock();
130 
131         return NULL;
132 }
133 
134 static inline struct lowpan_peer *
135 __peer_lookup_chan(struct lowpan_btle_dev *dev, struct l2cap_chan *chan)
136 {
137         struct lowpan_peer *peer;
138 
139         list_for_each_entry_rcu(peer, &dev->peers, list) {
140                 if (peer->chan == chan)
141                         return peer;
142         }
143 
144         return NULL;
145 }
146 
147 static inline struct lowpan_peer *
148 __peer_lookup_conn(struct lowpan_btle_dev *dev, struct l2cap_conn *conn)
149 {
150         struct lowpan_peer *peer;
151 
152         list_for_each_entry_rcu(peer, &dev->peers, list) {
153                 if (peer->chan->conn == conn)
154                         return peer;
155         }
156 
157         return NULL;
158 }
159 
160 static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_btle_dev *dev,
161                                                   struct in6_addr *daddr,
162                                                   struct sk_buff *skb)
163 {
164         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
165         int count = atomic_read(&dev->peer_count);
166         const struct in6_addr *nexthop;
167         struct lowpan_peer *peer;
168         struct neighbour *neigh;
169 
170         BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);
171 
172         if (!rt) {
173                 if (ipv6_addr_any(&lowpan_cb(skb)->gw)) {
174                         /* There is neither route nor gateway,
175                          * probably the destination is a direct peer.
176                          */
177                         nexthop = daddr;
178                 } else {
179                         /* There is a known gateway
180                          */
181                         nexthop = &lowpan_cb(skb)->gw;
182                 }
183         } else {
184                 nexthop = rt6_nexthop(rt, daddr);
185 
186                 /* We need to remember the address because it is needed
187                  * by bt_xmit() when sending the packet. In bt_xmit(), the
188                  * destination routing info is not set.
189                  */
190                 memcpy(&lowpan_cb(skb)->gw, nexthop, sizeof(struct in6_addr));
191         }
192 
193         BT_DBG("gw %pI6c", nexthop);
194 
195         rcu_read_lock();
196 
197         list_for_each_entry_rcu(peer, &dev->peers, list) {
198                 BT_DBG("dst addr %pMR dst type %d ip %pI6c",
199                        &peer->chan->dst, peer->chan->dst_type,
200                        &peer->peer_addr);
201 
202                 if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
203                         rcu_read_unlock();
204                         return peer;
205                 }
206         }
207 
208         /* use the neighbour cache for matching addresses assigned by SLAAC
209         */
210         neigh = __ipv6_neigh_lookup(dev->netdev, nexthop);
211         if (neigh) {
212                 list_for_each_entry_rcu(peer, &dev->peers, list) {
213                         if (!memcmp(neigh->ha, peer->lladdr, ETH_ALEN)) {
214                                 neigh_release(neigh);
215                                 rcu_read_unlock();
216                                 return peer;
217                         }
218                 }
219                 neigh_release(neigh);
220         }
221 
222         rcu_read_unlock();
223 
224         return NULL;
225 }
226 
227 static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
228 {
229         struct lowpan_btle_dev *entry;
230         struct lowpan_peer *peer = NULL;
231 
232         rcu_read_lock();
233 
234         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
235                 peer = __peer_lookup_conn(entry, conn);
236                 if (peer)
237                         break;
238         }
239 
240         rcu_read_unlock();
241 
242         return peer;
243 }
244 
245 static struct lowpan_btle_dev *lookup_dev(struct l2cap_conn *conn)
246 {
247         struct lowpan_btle_dev *entry;
248         struct lowpan_btle_dev *dev = NULL;
249 
250         rcu_read_lock();
251 
252         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
253                 if (conn->hcon->hdev == entry->hdev) {
254                         dev = entry;
255                         break;
256                 }
257         }
258 
259         rcu_read_unlock();
260 
261         return dev;
262 }
263 
264 static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
265 {
266         struct sk_buff *skb_cp;
267 
268         skb_cp = skb_copy(skb, GFP_ATOMIC);
269         if (!skb_cp)
270                 return NET_RX_DROP;
271 
272         return netif_rx_ni(skb_cp);
273 }
274 
275 static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
276                            struct lowpan_peer *peer)
277 {
278         const u8 *saddr;
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, &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 const 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, NULL);
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         rtnl_lock();
622         dev_close(netdev);
623         rtnl_unlock();
624 }
625 
626 static void do_notify_peers(struct work_struct *work)
627 {
628         struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_dev,
629                                                    notify_peers.work);
630 
631         netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
632 }
633 
634 static bool is_bt_6lowpan(struct hci_conn *hcon)
635 {
636         if (hcon->type != LE_LINK)
637                 return false;
638 
639         if (!enable_6lowpan)
640                 return false;
641 
642         return true;
643 }
644 
645 static struct l2cap_chan *chan_create(void)
646 {
647         struct l2cap_chan *chan;
648 
649         chan = l2cap_chan_create();
650         if (!chan)
651                 return NULL;
652 
653         l2cap_chan_set_defaults(chan);
654 
655         chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
656         chan->mode = L2CAP_MODE_LE_FLOWCTL;
657         chan->imtu = 1280;
658 
659         return chan;
660 }
661 
662 static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
663                                         struct lowpan_btle_dev *dev,
664                                         bool new_netdev)
665 {
666         struct lowpan_peer *peer;
667 
668         peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
669         if (!peer)
670                 return NULL;
671 
672         peer->chan = chan;
673         memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
674 
675         baswap((void *)peer->lladdr, &chan->dst);
676 
677         lowpan_iphc_uncompress_eui48_lladdr(&peer->peer_addr, peer->lladdr);
678 
679         spin_lock(&devices_lock);
680         INIT_LIST_HEAD(&peer->list);
681         peer_add(dev, peer);
682         spin_unlock(&devices_lock);
683 
684         /* Notifying peers about us needs to be done without locks held */
685         if (new_netdev)
686                 INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
687         schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
688 
689         return peer->chan;
690 }
691 
692 static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
693 {
694         struct net_device *netdev;
695         int err = 0;
696 
697         netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
698                               IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
699                               netdev_setup);
700         if (!netdev)
701                 return -ENOMEM;
702 
703         netdev->addr_assign_type = NET_ADDR_PERM;
704         baswap((void *)netdev->dev_addr, &chan->src);
705 
706         netdev->netdev_ops = &netdev_ops;
707         SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
708         SET_NETDEV_DEVTYPE(netdev, &bt_type);
709 
710         *dev = lowpan_btle_dev(netdev);
711         (*dev)->netdev = netdev;
712         (*dev)->hdev = chan->conn->hcon->hdev;
713         INIT_LIST_HEAD(&(*dev)->peers);
714 
715         spin_lock(&devices_lock);
716         INIT_LIST_HEAD(&(*dev)->list);
717         list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
718         spin_unlock(&devices_lock);
719 
720         err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
721         if (err < 0) {
722                 BT_INFO("register_netdev failed %d", err);
723                 spin_lock(&devices_lock);
724                 list_del_rcu(&(*dev)->list);
725                 spin_unlock(&devices_lock);
726                 free_netdev(netdev);
727                 goto out;
728         }
729 
730         BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
731                netdev->ifindex, &chan->dst, chan->dst_type,
732                &chan->src, chan->src_type);
733         set_bit(__LINK_STATE_PRESENT, &netdev->state);
734 
735         return 0;
736 
737 out:
738         return err;
739 }
740 
741 static inline void chan_ready_cb(struct l2cap_chan *chan)
742 {
743         struct lowpan_btle_dev *dev;
744         bool new_netdev = false;
745 
746         dev = lookup_dev(chan->conn);
747 
748         BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
749 
750         if (!dev) {
751                 if (setup_netdev(chan, &dev) < 0) {
752                         l2cap_chan_del(chan, -ENOENT);
753                         return;
754                 }
755                 new_netdev = true;
756         }
757 
758         if (!try_module_get(THIS_MODULE))
759                 return;
760 
761         add_peer_chan(chan, dev, new_netdev);
762         ifup(dev->netdev);
763 }
764 
765 static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
766 {
767         struct l2cap_chan *chan;
768 
769         chan = chan_create();
770         if (!chan)
771                 return NULL;
772 
773         chan->ops = pchan->ops;
774 
775         BT_DBG("chan %p pchan %p", chan, pchan);
776 
777         return chan;
778 }
779 
780 static void delete_netdev(struct work_struct *work)
781 {
782         struct lowpan_btle_dev *entry = container_of(work,
783                                                      struct lowpan_btle_dev,
784                                                      delete_netdev);
785 
786         lowpan_unregister_netdev(entry->netdev);
787 
788         /* The entry pointer is deleted by the netdev destructor. */
789 }
790 
791 static void chan_close_cb(struct l2cap_chan *chan)
792 {
793         struct lowpan_btle_dev *entry;
794         struct lowpan_btle_dev *dev = NULL;
795         struct lowpan_peer *peer;
796         int err = -ENOENT;
797         bool last = false, remove = true;
798 
799         BT_DBG("chan %p conn %p", chan, chan->conn);
800 
801         if (chan->conn && chan->conn->hcon) {
802                 if (!is_bt_6lowpan(chan->conn->hcon))
803                         return;
804 
805                 /* If conn is set, then the netdev is also there and we should
806                  * not remove it.
807                  */
808                 remove = false;
809         }
810 
811         spin_lock(&devices_lock);
812 
813         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
814                 dev = lowpan_btle_dev(entry->netdev);
815                 peer = __peer_lookup_chan(dev, chan);
816                 if (peer) {
817                         last = peer_del(dev, peer);
818                         err = 0;
819 
820                         BT_DBG("dev %p removing %speer %p", dev,
821                                last ? "last " : "1 ", peer);
822                         BT_DBG("chan %p orig refcnt %d", chan,
823                                kref_read(&chan->kref));
824 
825                         l2cap_chan_put(chan);
826                         break;
827                 }
828         }
829 
830         if (!err && last && dev && !atomic_read(&dev->peer_count)) {
831                 spin_unlock(&devices_lock);
832 
833                 cancel_delayed_work_sync(&dev->notify_peers);
834 
835                 ifdown(dev->netdev);
836 
837                 if (remove) {
838                         INIT_WORK(&entry->delete_netdev, delete_netdev);
839                         schedule_work(&entry->delete_netdev);
840                 }
841         } else {
842                 spin_unlock(&devices_lock);
843         }
844 
845         return;
846 }
847 
848 static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
849 {
850         BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
851                state_to_string(state), err);
852 }
853 
854 static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
855                                          unsigned long hdr_len,
856                                          unsigned long len, int nb)
857 {
858         /* Note that we must allocate using GFP_ATOMIC here as
859          * this function is called originally from netdev hard xmit
860          * function in atomic context.
861          */
862         return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
863 }
864 
865 static void chan_suspend_cb(struct l2cap_chan *chan)
866 {
867         struct lowpan_btle_dev *dev;
868 
869         BT_DBG("chan %p suspend", chan);
870 
871         dev = lookup_dev(chan->conn);
872         if (!dev || !dev->netdev)
873                 return;
874 
875         netif_stop_queue(dev->netdev);
876 }
877 
878 static void chan_resume_cb(struct l2cap_chan *chan)
879 {
880         struct lowpan_btle_dev *dev;
881 
882         BT_DBG("chan %p resume", chan);
883 
884         dev = lookup_dev(chan->conn);
885         if (!dev || !dev->netdev)
886                 return;
887 
888         netif_wake_queue(dev->netdev);
889 }
890 
891 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
892 {
893         return L2CAP_CONN_TIMEOUT;
894 }
895 
896 static const struct l2cap_ops bt_6lowpan_chan_ops = {
897         .name                   = "L2CAP 6LoWPAN channel",
898         .new_connection         = chan_new_conn_cb,
899         .recv                   = chan_recv_cb,
900         .close                  = chan_close_cb,
901         .state_change           = chan_state_change_cb,
902         .ready                  = chan_ready_cb,
903         .resume                 = chan_resume_cb,
904         .suspend                = chan_suspend_cb,
905         .get_sndtimeo           = chan_get_sndtimeo_cb,
906         .alloc_skb              = chan_alloc_skb_cb,
907 
908         .teardown               = l2cap_chan_no_teardown,
909         .defer                  = l2cap_chan_no_defer,
910         .set_shutdown           = l2cap_chan_no_set_shutdown,
911 };
912 
913 static inline __u8 bdaddr_type(__u8 type)
914 {
915         if (type == ADDR_LE_DEV_PUBLIC)
916                 return BDADDR_LE_PUBLIC;
917         else
918                 return BDADDR_LE_RANDOM;
919 }
920 
921 static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
922 {
923         struct l2cap_chan *chan;
924         int err;
925 
926         chan = chan_create();
927         if (!chan)
928                 return -EINVAL;
929 
930         chan->ops = &bt_6lowpan_chan_ops;
931 
932         err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
933                                  addr, dst_type);
934 
935         BT_DBG("chan %p err %d", chan, err);
936         if (err < 0)
937                 l2cap_chan_put(chan);
938 
939         return err;
940 }
941 
942 static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
943 {
944         struct lowpan_peer *peer;
945 
946         BT_DBG("conn %p dst type %d", conn, dst_type);
947 
948         peer = lookup_peer(conn);
949         if (!peer)
950                 return -ENOENT;
951 
952         BT_DBG("peer %p chan %p", peer, peer->chan);
953 
954         l2cap_chan_close(peer->chan, ENOENT);
955 
956         return 0;
957 }
958 
959 static struct l2cap_chan *bt_6lowpan_listen(void)
960 {
961         bdaddr_t *addr = BDADDR_ANY;
962         struct l2cap_chan *chan;
963         int err;
964 
965         if (!enable_6lowpan)
966                 return NULL;
967 
968         chan = chan_create();
969         if (!chan)
970                 return NULL;
971 
972         chan->ops = &bt_6lowpan_chan_ops;
973         chan->state = BT_LISTEN;
974         chan->src_type = BDADDR_LE_PUBLIC;
975 
976         atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
977 
978         BT_DBG("chan %p src type %d", chan, chan->src_type);
979 
980         err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
981         if (err) {
982                 l2cap_chan_put(chan);
983                 BT_ERR("psm cannot be added err %d", err);
984                 return NULL;
985         }
986 
987         return chan;
988 }
989 
990 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
991                           struct l2cap_conn **conn)
992 {
993         struct hci_conn *hcon;
994         struct hci_dev *hdev;
995         int n;
996 
997         n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
998                    &addr->b[5], &addr->b[4], &addr->b[3],
999                    &addr->b[2], &addr->b[1], &addr->b[0],
1000                    addr_type);
1001 
1002         if (n < 7)
1003                 return -EINVAL;
1004 
1005         /* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
1006         hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
1007         if (!hdev)
1008                 return -ENOENT;
1009 
1010         hci_dev_lock(hdev);
1011         hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
1012         hci_dev_unlock(hdev);
1013 
1014         if (!hcon)
1015                 return -ENOENT;
1016 
1017         *conn = (struct l2cap_conn *)hcon->l2cap_data;
1018 
1019         BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);
1020 
1021         return 0;
1022 }
1023 
1024 static void disconnect_all_peers(void)
1025 {
1026         struct lowpan_btle_dev *entry;
1027         struct lowpan_peer *peer, *tmp_peer, *new_peer;
1028         struct list_head peers;
1029 
1030         INIT_LIST_HEAD(&peers);
1031 
1032         /* We make a separate list of peers as the close_cb() will
1033          * modify the device peers list so it is better not to mess
1034          * with the same list at the same time.
1035          */
1036 
1037         rcu_read_lock();
1038 
1039         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1040                 list_for_each_entry_rcu(peer, &entry->peers, list) {
1041                         new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1042                         if (!new_peer)
1043                                 break;
1044 
1045                         new_peer->chan = peer->chan;
1046                         INIT_LIST_HEAD(&new_peer->list);
1047 
1048                         list_add(&new_peer->list, &peers);
1049                 }
1050         }
1051 
1052         rcu_read_unlock();
1053 
1054         spin_lock(&devices_lock);
1055         list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1056                 l2cap_chan_close(peer->chan, ENOENT);
1057 
1058                 list_del_rcu(&peer->list);
1059                 kfree_rcu(peer, rcu);
1060         }
1061         spin_unlock(&devices_lock);
1062 }
1063 
1064 struct set_enable {
1065         struct work_struct work;
1066         bool flag;
1067 };
1068 
1069 static void do_enable_set(struct work_struct *work)
1070 {
1071         struct set_enable *set_enable = container_of(work,
1072                                                      struct set_enable, work);
1073 
1074         if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1075                 /* Disconnect existing connections if 6lowpan is
1076                  * disabled
1077                  */
1078                 disconnect_all_peers();
1079 
1080         enable_6lowpan = set_enable->flag;
1081 
1082         mutex_lock(&set_lock);
1083         if (listen_chan) {
1084                 l2cap_chan_close(listen_chan, 0);
1085                 l2cap_chan_put(listen_chan);
1086         }
1087 
1088         listen_chan = bt_6lowpan_listen();
1089         mutex_unlock(&set_lock);
1090 
1091         kfree(set_enable);
1092 }
1093 
1094 static int lowpan_enable_set(void *data, u64 val)
1095 {
1096         struct set_enable *set_enable;
1097 
1098         set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1099         if (!set_enable)
1100                 return -ENOMEM;
1101 
1102         set_enable->flag = !!val;
1103         INIT_WORK(&set_enable->work, do_enable_set);
1104 
1105         schedule_work(&set_enable->work);
1106 
1107         return 0;
1108 }
1109 
1110 static int lowpan_enable_get(void *data, u64 *val)
1111 {
1112         *val = enable_6lowpan;
1113         return 0;
1114 }
1115 
1116 DEFINE_DEBUGFS_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1117                          lowpan_enable_set, "%llu\n");
1118 
1119 static ssize_t lowpan_control_write(struct file *fp,
1120                                     const char __user *user_buffer,
1121                                     size_t count,
1122                                     loff_t *position)
1123 {
1124         char buf[32];
1125         size_t buf_size = min(count, sizeof(buf) - 1);
1126         int ret;
1127         bdaddr_t addr;
1128         u8 addr_type;
1129         struct l2cap_conn *conn = NULL;
1130 
1131         if (copy_from_user(buf, user_buffer, buf_size))
1132                 return -EFAULT;
1133 
1134         buf[buf_size] = '\0';
1135 
1136         if (memcmp(buf, "connect ", 8) == 0) {
1137                 ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1138                 if (ret == -EINVAL)
1139                         return ret;
1140 
1141                 mutex_lock(&set_lock);
1142                 if (listen_chan) {
1143                         l2cap_chan_close(listen_chan, 0);
1144                         l2cap_chan_put(listen_chan);
1145                         listen_chan = NULL;
1146                 }
1147                 mutex_unlock(&set_lock);
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_unsafe("6lowpan_enable",
1289                                                            0644, bt_debugfs,
1290                                                            NULL,
1291                                                            &lowpan_enable_fops);
1292         lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1293                                                      bt_debugfs, NULL,
1294                                                      &lowpan_control_fops);
1295 
1296         return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1297 }
1298 
1299 static void __exit bt_6lowpan_exit(void)
1300 {
1301         debugfs_remove(lowpan_enable_debugfs);
1302         debugfs_remove(lowpan_control_debugfs);
1303 
1304         if (listen_chan) {
1305                 l2cap_chan_close(listen_chan, 0);
1306                 l2cap_chan_put(listen_chan);
1307         }
1308 
1309         disconnect_devices();
1310 
1311         unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1312 }
1313 
1314 module_init(bt_6lowpan_init);
1315 module_exit(bt_6lowpan_exit);
1316 
1317 MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1318 MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1319 MODULE_VERSION(VERSION);
1320 MODULE_LICENSE("GPL");
1321 

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