net/bluetooth/6lowpan.c

   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
  54 struct lowpan_peer {
  55         struct list_head list;
  56         struct rcu_head rcu;
  57         struct l2cap_chan *chan;
  58
  59         /* peer addresses in various formats */
  60         unsigned char lladdr[ETH_ALEN];
  61         struct in6_addr peer_addr;
  62 };
  63
  64 struct lowpan_btle_dev {
  65         struct list_head list;
  66
  67         struct hci_dev *hdev;
  68         struct net_device *netdev;
  69         struct list_head peers;
  70         atomic_t peer_count; /* number of items in peers list */
  71
  72         struct work_struct delete_netdev;
  73         struct delayed_work notify_peers;
  74 };
  75
  76 static inline struct lowpan_btle_dev *
  77 lowpan_btle_dev(const struct net_device *netdev)
  78 {
  79         return (struct lowpan_btle_dev *)lowpan_dev(netdev)->priv;
  80 }
  81
  82 static inline void peer_add(struct lowpan_btle_dev *dev,
  83                             struct lowpan_peer *peer)
  84 {
  85         list_add_rcu(&peer->list, &dev->peers);
  86         atomic_inc(&dev->peer_count);
  87 }
  88
  89 static inline bool peer_del(struct lowpan_btle_dev *dev,
  90                             struct lowpan_peer *peer)
  91 {
  92         list_del_rcu(&peer->list);
  93         kfree_rcu(peer, rcu);
  94
  95         module_put(THIS_MODULE);
  96
  97         if (atomic_dec_and_test(&dev->peer_count)) {
  98                 BT_DBG("last peer");
  99                 return true;
 100         }
 101
 102         return false;
 103 }
 104
 105 static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_btle_dev *dev,
 106                                                  bdaddr_t *ba, __u8 type)
 107 {
 108         struct lowpan_peer *peer;
 109
 110         BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
 111                ba, type);
 112
 113         rcu_read_lock();
 114
 115         list_for_each_entry_rcu(peer, &dev->peers, list) {
 116                 BT_DBG("dst addr %pMR dst type %d",
 117                        &peer->chan->dst, peer->chan->dst_type);
 118
 119                 if (bacmp(&peer->chan->dst, ba))
 120                         continue;
 121
 122                 if (type == peer->chan->dst_type) {
 123                         rcu_read_unlock();
 124                         return peer;
 125                 }
 126         }
 127
 128         rcu_read_unlock();
 129
 130         return NULL;
 131 }
 132
 133 static inline struct lowpan_peer *
 134 __peer_lookup_chan(struct lowpan_btle_dev *dev, struct l2cap_chan *chan)
 135 {
 136         struct lowpan_peer *peer;
 137
 138         list_for_each_entry_rcu(peer, &dev->peers, list) {
 139                 if (peer->chan == chan)
 140                         return peer;
 141         }
 142
 143         return NULL;
 144 }
 145
 146 static inline struct lowpan_peer *
 147 __peer_lookup_conn(struct lowpan_btle_dev *dev, struct l2cap_conn *conn)
 148 {
 149         struct lowpan_peer *peer;
 150
 151         list_for_each_entry_rcu(peer, &dev->peers, list) {
 152                 if (peer->chan->conn == conn)
 153                         return peer;
 154         }
 155
 156         return NULL;
 157 }
 158
 159 static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_btle_dev *dev,
 160                                                   struct in6_addr *daddr,
 161                                                   struct sk_buff *skb)
 162 {
 163         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 164         int count = atomic_read(&dev->peer_count);
 165         const struct in6_addr *nexthop;
 166         struct lowpan_peer *peer;
 167         struct neighbour *neigh;
 168
 169         BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);
 170
 171         if (!rt) {
 172                 if (ipv6_addr_any(&lowpan_cb(skb)->gw)) {
 173                         /* There is neither route nor gateway,
 174                          * probably the destination is a direct peer.
 175                          */
 176                         nexthop = daddr;
 177                 } else {
 178                         /* There is a known gateway
 179                          */
 180                         nexthop = &lowpan_cb(skb)->gw;
 181                 }
 182         } else {
 183                 nexthop = rt6_nexthop(rt, daddr);
 184
 185                 /* We need to remember the address because it is needed
 186                  * by bt_xmit() when sending the packet. In bt_xmit(), the
 187                  * destination routing info is not set.
 188                  */
 189                 memcpy(&lowpan_cb(skb)->gw, nexthop, sizeof(struct in6_addr));
 190         }
 191
 192         BT_DBG("gw %pI6c", nexthop);
 193
 194         rcu_read_lock();
 195
 196         list_for_each_entry_rcu(peer, &dev->peers, list) {
 197                 BT_DBG("dst addr %pMR dst type %d ip %pI6c",
 198                        &peer->chan->dst, peer->chan->dst_type,
 199                        &peer->peer_addr);
 200
 201                 if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
 202                         rcu_read_unlock();
 203                         return peer;
 204                 }
 205         }
 206
 207         /* use the neighbour cache for matching addresses assigned by SLAAC
 208         */
 209         neigh = __ipv6_neigh_lookup(dev->netdev, nexthop);
 210         if (neigh) {
 211                 list_for_each_entry_rcu(peer, &dev->peers, list) {
 212                         if (!memcmp(neigh->ha, peer->lladdr, ETH_ALEN)) {
 213                                 neigh_release(neigh);
 214                                 rcu_read_unlock();
 215                                 return peer;
 216                         }
 217                 }
 218                 neigh_release(neigh);
 219         }
 220
 221         rcu_read_unlock();
 222
 223         return NULL;
 224 }
 225
 226 static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
 227 {
 228         struct lowpan_btle_dev *entry;
 229         struct lowpan_peer *peer = NULL;
 230
 231         rcu_read_lock();
 232
 233         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 234                 peer = __peer_lookup_conn(entry, conn);
 235                 if (peer)
 236                         break;
 237         }
 238
 239         rcu_read_unlock();
 240
 241         return peer;
 242 }
 243
 244 static struct lowpan_btle_dev *lookup_dev(struct l2cap_conn *conn)
 245 {
 246         struct lowpan_btle_dev *entry;
 247         struct lowpan_btle_dev *dev = NULL;
 248
 249         rcu_read_lock();
 250
 251         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 252                 if (conn->hcon->hdev == entry->hdev) {
 253                         dev = entry;
 254                         break;
 255                 }
 256         }
 257
 258         rcu_read_unlock();
 259
 260         return dev;
 261 }
 262
 263 static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
 264 {
 265         struct sk_buff *skb_cp;
 266
 267         skb_cp = skb_copy(skb, GFP_ATOMIC);
 268         if (!skb_cp)
 269                 return NET_RX_DROP;
 270
 271         return netif_rx_ni(skb_cp);
 272 }
 273
 274 static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
 275                            struct lowpan_peer *peer)
 276 {
 277         const u8 *saddr;
 278
 279         saddr = peer->lladdr;
 280
 281         return lowpan_header_decompress(skb, netdev, netdev->dev_addr, saddr);
 282 }
 283
 284 static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 285                     struct lowpan_peer *peer)
 286 {
 287         struct sk_buff *local_skb;
 288         int ret;
 289
 290         if (!netif_running(dev))
 291                 goto drop;
 292
 293         if (dev->type != ARPHRD_6LOWPAN || !skb->len)
 294                 goto drop;
 295
 296         skb_reset_network_header(skb);
 297
 298         skb = skb_share_check(skb, GFP_ATOMIC);
 299         if (!skb)
 300                 goto drop;
 301
 302         /* check that it's our buffer */
 303         if (lowpan_is_ipv6(*skb_network_header(skb))) {
 304                 /* Pull off the 1-byte of 6lowpan header. */
 305                 skb_pull(skb, 1);
 306
 307                 /* Copy the packet so that the IPv6 header is
 308                  * properly aligned.
 309                  */
 310                 local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
 311                                             skb_tailroom(skb), GFP_ATOMIC);
 312                 if (!local_skb)
 313                         goto drop;
 314
 315                 local_skb->protocol = htons(ETH_P_IPV6);
 316                 local_skb->pkt_type = PACKET_HOST;
 317                 local_skb->dev = dev;
 318
 319                 skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
 320
 321                 if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
 322                         kfree_skb(local_skb);
 323                         goto drop;
 324                 }
 325
 326                 dev->stats.rx_bytes += skb->len;
 327                 dev->stats.rx_packets++;
 328
 329                 consume_skb(local_skb);
 330                 consume_skb(skb);
 331         } else if (lowpan_is_iphc(*skb_network_header(skb))) {
 332                 local_skb = skb_clone(skb, GFP_ATOMIC);
 333                 if (!local_skb)
 334                         goto drop;
 335
 336                 local_skb->dev = dev;
 337
 338                 ret = iphc_decompress(local_skb, dev, peer);
 339                 if (ret < 0) {
 340                         BT_DBG("iphc_decompress failed: %d", ret);
 341                         kfree_skb(local_skb);
 342                         goto drop;
 343                 }
 344
 345                 local_skb->protocol = htons(ETH_P_IPV6);
 346                 local_skb->pkt_type = PACKET_HOST;
 347
 348                 if (give_skb_to_upper(local_skb, dev)
 349                                 != NET_RX_SUCCESS) {
 350                         kfree_skb(local_skb);
 351                         goto drop;
 352                 }
 353
 354                 dev->stats.rx_bytes += skb->len;
 355                 dev->stats.rx_packets++;
 356
 357                 consume_skb(local_skb);
 358                 consume_skb(skb);
 359         } else {
 360                 BT_DBG("unknown packet type");
 361                 goto drop;
 362         }
 363
 364         return NET_RX_SUCCESS;
 365
 366 drop:
 367         dev->stats.rx_dropped++;
 368         return NET_RX_DROP;
 369 }
 370
 371 /* Packet from BT LE device */
 372 static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
 373 {
 374         struct lowpan_btle_dev *dev;
 375         struct lowpan_peer *peer;
 376         int err;
 377
 378         peer = lookup_peer(chan->conn);
 379         if (!peer)
 380                 return -ENOENT;
 381
 382         dev = lookup_dev(chan->conn);
 383         if (!dev || !dev->netdev)
 384                 return -ENOENT;
 385
 386         err = recv_pkt(skb, dev->netdev, peer);
 387         if (err) {
 388                 BT_DBG("recv pkt %d", err);
 389                 err = -EAGAIN;
 390         }
 391
 392         return err;
 393 }
 394
 395 static int setup_header(struct sk_buff *skb, struct net_device *netdev,
 396                         bdaddr_t *peer_addr, u8 *peer_addr_type)
 397 {
 398         struct in6_addr ipv6_daddr;
 399         struct ipv6hdr *hdr;
 400         struct lowpan_btle_dev *dev;
 401         struct lowpan_peer *peer;
 402         u8 *daddr;
 403         int err, status = 0;
 404
 405         hdr = ipv6_hdr(skb);
 406
 407         dev = lowpan_btle_dev(netdev);
 408
 409         memcpy(&ipv6_daddr, &hdr->daddr, sizeof(ipv6_daddr));
 410
 411         if (ipv6_addr_is_multicast(&ipv6_daddr)) {
 412                 lowpan_cb(skb)->chan = NULL;
 413                 daddr = NULL;
 414         } else {
 415                 BT_DBG("dest IP %pI6c", &ipv6_daddr);
 416
 417                 /* The packet might be sent to 6lowpan interface
 418                  * because of routing (either via default route
 419                  * or user set route) so get peer according to
 420                  * the destination address.
 421                  */
 422                 peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
 423                 if (!peer) {
 424                         BT_DBG("no such peer");
 425                         return -ENOENT;
 426                 }
 427
 428                 daddr = peer->lladdr;
 429                 *peer_addr = peer->chan->dst;
 430                 *peer_addr_type = peer->chan->dst_type;
 431                 lowpan_cb(skb)->chan = peer->chan;
 432
 433                 status = 1;
 434         }
 435
 436         lowpan_header_compress(skb, netdev, daddr, dev->netdev->dev_addr);
 437
 438         err = dev_hard_header(skb, netdev, ETH_P_IPV6, NULL, NULL, 0);
 439         if (err < 0)
 440                 return err;
 441
 442         return status;
 443 }
 444
 445 static int header_create(struct sk_buff *skb, struct net_device *netdev,
 446                          unsigned short type, const void *_daddr,
 447                          const void *_saddr, unsigned int len)
 448 {
 449         if (type != ETH_P_IPV6)
 450                 return -EINVAL;
 451
 452         return 0;
 453 }
 454
 455 /* Packet to BT LE device */
 456 static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
 457                     struct net_device *netdev)
 458 {
 459         struct msghdr msg;
 460         struct kvec iv;
 461         int err;
 462
 463         /* Remember the skb so that we can send EAGAIN to the caller if
 464          * we run out of credits.
 465          */
 466         chan->data = skb;
 467
 468         iv.iov_base = skb->data;
 469         iv.iov_len = skb->len;
 470
 471         memset(&msg, 0, sizeof(msg));
 472         iov_iter_kvec(&msg.msg_iter, WRITE, &iv, 1, skb->len);
 473
 474         err = l2cap_chan_send(chan, &msg, skb->len);
 475         if (err > 0) {
 476                 netdev->stats.tx_bytes += err;
 477                 netdev->stats.tx_packets++;
 478                 return 0;
 479         }
 480
 481         if (err < 0)
 482                 netdev->stats.tx_errors++;
 483
 484         return err;
 485 }
 486
 487 static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
 488 {
 489         struct sk_buff *local_skb;
 490         struct lowpan_btle_dev *entry;
 491         int err = 0;
 492
 493         rcu_read_lock();
 494
 495         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 496                 struct lowpan_peer *pentry;
 497                 struct lowpan_btle_dev *dev;
 498
 499                 if (entry->netdev != netdev)
 500                         continue;
 501
 502                 dev = lowpan_btle_dev(entry->netdev);
 503
 504                 list_for_each_entry_rcu(pentry, &dev->peers, list) {
 505                         int ret;
 506
 507                         local_skb = skb_clone(skb, GFP_ATOMIC);
 508
 509                         BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
 510                                netdev->name,
 511                                &pentry->chan->dst, pentry->chan->dst_type,
 512                                &pentry->peer_addr, pentry->chan);
 513                         ret = send_pkt(pentry->chan, local_skb, netdev);
 514                         if (ret < 0)
 515                                 err = ret;
 516
 517                         kfree_skb(local_skb);
 518                 }
 519         }
 520
 521         rcu_read_unlock();
 522
 523         return err;
 524 }
 525
 526 static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
 527 {
 528         int err = 0;
 529         bdaddr_t addr;
 530         u8 addr_type;
 531
 532         /* We must take a copy of the skb before we modify/replace the ipv6
 533          * header as the header could be used elsewhere
 534          */
 535         skb = skb_unshare(skb, GFP_ATOMIC);
 536         if (!skb)
 537                 return NET_XMIT_DROP;
 538
 539         /* Return values from setup_header()
 540          *  <0 - error, packet is dropped
 541          *   0 - this is a multicast packet
 542          *   1 - this is unicast packet
 543          */
 544         err = setup_header(skb, netdev, &addr, &addr_type);
 545         if (err < 0) {
 546                 kfree_skb(skb);
 547                 return NET_XMIT_DROP;
 548         }
 549
 550         if (err) {
 551                 if (lowpan_cb(skb)->chan) {
 552                         BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
 553                                netdev->name, &addr, addr_type,
 554                                &lowpan_cb(skb)->addr, lowpan_cb(skb)->chan);
 555                         err = send_pkt(lowpan_cb(skb)->chan, skb, netdev);
 556                 } else {
 557                         err = -ENOENT;
 558                 }
 559         } else {
 560                 /* We need to send the packet to every device behind this
 561                  * interface.
 562                  */
 563                 err = send_mcast_pkt(skb, netdev);
 564         }
 565
 566         dev_kfree_skb(skb);
 567
 568         if (err)
 569                 BT_DBG("ERROR: xmit failed (%d)", err);
 570
 571         return err < 0 ? NET_XMIT_DROP : err;
 572 }
 573
 574 static const struct net_device_ops netdev_ops = {
 575         .ndo_start_xmit         = bt_xmit,
 576 };
 577
 578 static const struct header_ops header_ops = {
 579         .create = header_create,
 580 };
 581
 582 static void netdev_setup(struct net_device *dev)
 583 {
 584         dev->hard_header_len    = 0;
 585         dev->needed_tailroom    = 0;
 586         dev->flags              = IFF_RUNNING | IFF_MULTICAST;
 587         dev->watchdog_timeo     = 0;
 588         dev->tx_queue_len       = DEFAULT_TX_QUEUE_LEN;
 589
 590         dev->netdev_ops         = &netdev_ops;
 591         dev->header_ops         = &header_ops;
 592         dev->needs_free_netdev  = true;
 593 }
 594
 595 static struct device_type bt_type = {
 596         .name   = "bluetooth",
 597 };
 598
 599 static void ifup(struct net_device *netdev)
 600 {
 601         int err;
 602
 603         rtnl_lock();
 604         err = dev_open(netdev, NULL);
 605         if (err < 0)
 606                 BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
 607         rtnl_unlock();
 608 }
 609
 610 static void ifdown(struct net_device *netdev)
 611 {
 612         rtnl_lock();
 613         dev_close(netdev);
 614         rtnl_unlock();
 615 }
 616
 617 static void do_notify_peers(struct work_struct *work)
 618 {
 619         struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_dev,
 620                                                    notify_peers.work);
 621
 622         netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
 623 }
 624
 625 static bool is_bt_6lowpan(struct hci_conn *hcon)
 626 {
 627         if (hcon->type != LE_LINK)
 628                 return false;
 629
 630         if (!enable_6lowpan)
 631                 return false;
 632
 633         return true;
 634 }
 635
 636 static struct l2cap_chan *chan_create(void)
 637 {
 638         struct l2cap_chan *chan;
 639
 640         chan = l2cap_chan_create();
 641         if (!chan)
 642                 return NULL;
 643
 644         l2cap_chan_set_defaults(chan);
 645
 646         chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
 647         chan->mode = L2CAP_MODE_LE_FLOWCTL;
 648         chan->imtu = 1280;
 649
 650         return chan;
 651 }
 652
 653 static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
 654                                         struct lowpan_btle_dev *dev,
 655                                         bool new_netdev)
 656 {
 657         struct lowpan_peer *peer;
 658
 659         peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
 660         if (!peer)
 661                 return NULL;
 662
 663         peer->chan = chan;
 664         memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
 665
 666         baswap((void *)peer->lladdr, &chan->dst);
 667
 668         lowpan_iphc_uncompress_eui48_lladdr(&peer->peer_addr, peer->lladdr);
 669
 670         spin_lock(&devices_lock);
 671         INIT_LIST_HEAD(&peer->list);
 672         peer_add(dev, peer);
 673         spin_unlock(&devices_lock);
 674
 675         /* Notifying peers about us needs to be done without locks held */
 676         if (new_netdev)
 677                 INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
 678         schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
 679
 680         return peer->chan;
 681 }
 682
 683 static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
 684 {
 685         struct net_device *netdev;
 686         int err = 0;
 687
 688         netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
 689                               IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
 690                               netdev_setup);
 691         if (!netdev)
 692                 return -ENOMEM;
 693
 694         netdev->addr_assign_type = NET_ADDR_PERM;
 695         baswap((void *)netdev->dev_addr, &chan->src);
 696
 697         netdev->netdev_ops = &netdev_ops;
 698         SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
 699         SET_NETDEV_DEVTYPE(netdev, &bt_type);
 700
 701         *dev = lowpan_btle_dev(netdev);
 702         (*dev)->netdev = netdev;
 703         (*dev)->hdev = chan->conn->hcon->hdev;
 704         INIT_LIST_HEAD(&(*dev)->peers);
 705
 706         spin_lock(&devices_lock);
 707         INIT_LIST_HEAD(&(*dev)->list);
 708         list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
 709         spin_unlock(&devices_lock);
 710
 711         err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
 712         if (err < 0) {
 713                 BT_INFO("register_netdev failed %d", err);
 714                 spin_lock(&devices_lock);
 715                 list_del_rcu(&(*dev)->list);
 716                 spin_unlock(&devices_lock);
 717                 free_netdev(netdev);
 718                 goto out;
 719         }
 720
 721         BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
 722                netdev->ifindex, &chan->dst, chan->dst_type,
 723                &chan->src, chan->src_type);
 724         set_bit(__LINK_STATE_PRESENT, &netdev->state);
 725
 726         return 0;
 727
 728 out:
 729         return err;
 730 }
 731
 732 static inline void chan_ready_cb(struct l2cap_chan *chan)
 733 {
 734         struct lowpan_btle_dev *dev;
 735         bool new_netdev = false;
 736
 737         dev = lookup_dev(chan->conn);
 738
 739         BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
 740
 741         if (!dev) {
 742                 if (setup_netdev(chan, &dev) < 0) {
 743                         l2cap_chan_del(chan, -ENOENT);
 744                         return;
 745                 }
 746                 new_netdev = true;
 747         }
 748
 749         if (!try_module_get(THIS_MODULE))
 750                 return;
 751
 752         add_peer_chan(chan, dev, new_netdev);
 753         ifup(dev->netdev);
 754 }
 755
 756 static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
 757 {
 758         struct l2cap_chan *chan;
 759
 760         chan = chan_create();
 761         if (!chan)
 762                 return NULL;
 763
 764         chan->ops = pchan->ops;
 765
 766         BT_DBG("chan %p pchan %p", chan, pchan);
 767
 768         return chan;
 769 }
 770
 771 static void delete_netdev(struct work_struct *work)
 772 {
 773         struct lowpan_btle_dev *entry = container_of(work,
 774                                                      struct lowpan_btle_dev,
 775                                                      delete_netdev);
 776
 777         lowpan_unregister_netdev(entry->netdev);
 778
 779         /* The entry pointer is deleted by the netdev destructor. */
 780 }
 781
 782 static void chan_close_cb(struct l2cap_chan *chan)
 783 {
 784         struct lowpan_btle_dev *entry;
 785         struct lowpan_btle_dev *dev = NULL;
 786         struct lowpan_peer *peer;
 787         int err = -ENOENT;
 788         bool last = false, remove = true;
 789
 790         BT_DBG("chan %p conn %p", chan, chan->conn);
 791
 792         if (chan->conn && chan->conn->hcon) {
 793                 if (!is_bt_6lowpan(chan->conn->hcon))
 794                         return;
 795
 796                 /* If conn is set, then the netdev is also there and we should
 797                  * not remove it.
 798                  */
 799                 remove = false;
 800         }
 801
 802         spin_lock(&devices_lock);
 803
 804         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 805                 dev = lowpan_btle_dev(entry->netdev);
 806                 peer = __peer_lookup_chan(dev, chan);
 807                 if (peer) {
 808                         last = peer_del(dev, peer);
 809                         err = 0;
 810
 811                         BT_DBG("dev %p removing %speer %p", dev,
 812                                last ? "last " : "1 ", peer);
 813                         BT_DBG("chan %p orig refcnt %d", chan,
 814                                kref_read(&chan->kref));
 815
 816                         l2cap_chan_put(chan);
 817                         break;
 818                 }
 819         }
 820
 821         if (!err && last && dev && !atomic_read(&dev->peer_count)) {
 822                 spin_unlock(&devices_lock);
 823
 824                 cancel_delayed_work_sync(&dev->notify_peers);
 825
 826                 ifdown(dev->netdev);
 827
 828                 if (remove) {
 829                         INIT_WORK(&entry->delete_netdev, delete_netdev);
 830                         schedule_work(&entry->delete_netdev);
 831                 }
 832         } else {
 833                 spin_unlock(&devices_lock);
 834         }
 835
 836         return;
 837 }
 838
 839 static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
 840 {
 841         BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
 842                state_to_string(state), err);
 843 }
 844
 845 static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
 846                                          unsigned long hdr_len,
 847                                          unsigned long len, int nb)
 848 {
 849         /* Note that we must allocate using GFP_ATOMIC here as
 850          * this function is called originally from netdev hard xmit
 851          * function in atomic context.
 852          */
 853         return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
 854 }
 855
 856 static void chan_suspend_cb(struct l2cap_chan *chan)
 857 {
 858         struct lowpan_btle_dev *dev;
 859
 860         BT_DBG("chan %p suspend", chan);
 861
 862         dev = lookup_dev(chan->conn);
 863         if (!dev || !dev->netdev)
 864                 return;
 865
 866         netif_stop_queue(dev->netdev);
 867 }
 868
 869 static void chan_resume_cb(struct l2cap_chan *chan)
 870 {
 871         struct lowpan_btle_dev *dev;
 872
 873         BT_DBG("chan %p resume", chan);
 874
 875         dev = lookup_dev(chan->conn);
 876         if (!dev || !dev->netdev)
 877                 return;
 878
 879         netif_wake_queue(dev->netdev);
 880 }
 881
 882 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
 883 {
 884         return L2CAP_CONN_TIMEOUT;
 885 }
 886
 887 static const struct l2cap_ops bt_6lowpan_chan_ops = {
 888         .name                   = "L2CAP 6LoWPAN channel",
 889         .new_connection         = chan_new_conn_cb,
 890         .recv                   = chan_recv_cb,
 891         .close                  = chan_close_cb,
 892         .state_change           = chan_state_change_cb,
 893         .ready                  = chan_ready_cb,
 894         .resume                 = chan_resume_cb,
 895         .suspend                = chan_suspend_cb,
 896         .get_sndtimeo           = chan_get_sndtimeo_cb,
 897         .alloc_skb              = chan_alloc_skb_cb,
 898
 899         .teardown               = l2cap_chan_no_teardown,
 900         .defer                  = l2cap_chan_no_defer,
 901         .set_shutdown           = l2cap_chan_no_set_shutdown,
 902 };
 903
 904 static inline __u8 bdaddr_type(__u8 type)
 905 {
 906         if (type == ADDR_LE_DEV_PUBLIC)
 907                 return BDADDR_LE_PUBLIC;
 908         else
 909                 return BDADDR_LE_RANDOM;
 910 }
 911
 912 static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
 913 {
 914         struct l2cap_chan *chan;
 915         int err;
 916
 917         chan = chan_create();
 918         if (!chan)
 919                 return -EINVAL;
 920
 921         chan->ops = &bt_6lowpan_chan_ops;
 922
 923         err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
 924                                  addr, dst_type);
 925
 926         BT_DBG("chan %p err %d", chan, err);
 927         if (err < 0)
 928                 l2cap_chan_put(chan);
 929
 930         return err;
 931 }
 932
 933 static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
 934 {
 935         struct lowpan_peer *peer;
 936
 937         BT_DBG("conn %p dst type %d", conn, dst_type);
 938
 939         peer = lookup_peer(conn);
 940         if (!peer)
 941                 return -ENOENT;
 942
 943         BT_DBG("peer %p chan %p", peer, peer->chan);
 944
 945         l2cap_chan_close(peer->chan, ENOENT);
 946
 947         return 0;
 948 }
 949
 950 static struct l2cap_chan *bt_6lowpan_listen(void)
 951 {
 952         bdaddr_t *addr = BDADDR_ANY;
 953         struct l2cap_chan *chan;
 954         int err;
 955
 956         if (!enable_6lowpan)
 957                 return NULL;
 958
 959         chan = chan_create();
 960         if (!chan)
 961                 return NULL;
 962
 963         chan->ops = &bt_6lowpan_chan_ops;
 964         chan->state = BT_LISTEN;
 965         chan->src_type = BDADDR_LE_PUBLIC;
 966
 967         atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
 968
 969         BT_DBG("chan %p src type %d", chan, chan->src_type);
 970
 971         err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
 972         if (err) {
 973                 l2cap_chan_put(chan);
 974                 BT_ERR("psm cannot be added err %d", err);
 975                 return NULL;
 976         }
 977
 978         return chan;
 979 }
 980
 981 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
 982                           struct l2cap_conn **conn)
 983 {
 984         struct hci_conn *hcon;
 985         struct hci_dev *hdev;
 986         int n;
 987
 988         n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
 989                    &addr->b[5], &addr->b[4], &addr->b[3],
 990                    &addr->b[2], &addr->b[1], &addr->b[0],
 991                    addr_type);
 992
 993         if (n < 7)
 994                 return -EINVAL;
 995
 996         /* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
 997         hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
 998         if (!hdev)
 999                 return -ENOENT;
1000
1001         hci_dev_lock(hdev);
1002         hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
1003         hci_dev_unlock(hdev);
1004
1005         if (!hcon)
1006                 return -ENOENT;
1007
1008         *conn = (struct l2cap_conn *)hcon->l2cap_data;
1009
1010         BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);
1011
1012         return 0;
1013 }
1014
1015 static void disconnect_all_peers(void)
1016 {
1017         struct lowpan_btle_dev *entry;
1018         struct lowpan_peer *peer, *tmp_peer, *new_peer;
1019         struct list_head peers;
1020
1021         INIT_LIST_HEAD(&peers);
1022
1023         /* We make a separate list of peers as the close_cb() will
1024          * modify the device peers list so it is better not to mess
1025          * with the same list at the same time.
1026          */
1027
1028         rcu_read_lock();
1029
1030         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1031                 list_for_each_entry_rcu(peer, &entry->peers, list) {
1032                         new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1033                         if (!new_peer)
1034                                 break;
1035
1036                         new_peer->chan = peer->chan;
1037                         INIT_LIST_HEAD(&new_peer->list);
1038
1039                         list_add(&new_peer->list, &peers);
1040                 }
1041         }
1042
1043         rcu_read_unlock();
1044
1045         spin_lock(&devices_lock);
1046         list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1047                 l2cap_chan_close(peer->chan, ENOENT);
1048
1049                 list_del_rcu(&peer->list);
1050                 kfree_rcu(peer, rcu);
1051         }
1052         spin_unlock(&devices_lock);
1053 }
1054
1055 struct set_enable {
1056         struct work_struct work;
1057         bool flag;
1058 };
1059
1060 static void do_enable_set(struct work_struct *work)
1061 {
1062         struct set_enable *set_enable = container_of(work,
1063                                                      struct set_enable, work);
1064
1065         if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1066                 /* Disconnect existing connections if 6lowpan is
1067                  * disabled
1068                  */
1069                 disconnect_all_peers();
1070
1071         enable_6lowpan = set_enable->flag;
1072
1073         if (listen_chan) {
1074                 l2cap_chan_close(listen_chan, 0);
1075                 l2cap_chan_put(listen_chan);
1076         }
1077
1078         listen_chan = bt_6lowpan_listen();
1079
1080         kfree(set_enable);
1081 }
1082
1083 static int lowpan_enable_set(void *data, u64 val)
1084 {
1085         struct set_enable *set_enable;
1086
1087         set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1088         if (!set_enable)
1089                 return -ENOMEM;
1090
1091         set_enable->flag = !!val;
1092         INIT_WORK(&set_enable->work, do_enable_set);
1093
1094         schedule_work(&set_enable->work);
1095
1096         return 0;
1097 }
1098
1099 static int lowpan_enable_get(void *data, u64 *val)
1100 {
1101         *val = enable_6lowpan;
1102         return 0;
1103 }
1104
1105 DEFINE_DEBUGFS_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1106                          lowpan_enable_set, "%llu\n");
1107
1108 static ssize_t lowpan_control_write(struct file *fp,
1109                                     const char __user *user_buffer,
1110                                     size_t count,
1111                                     loff_t *position)
1112 {
1113         char buf[32];
1114         size_t buf_size = min(count, sizeof(buf) - 1);
1115         int ret;
1116         bdaddr_t addr;
1117         u8 addr_type;
1118         struct l2cap_conn *conn = NULL;
1119
1120         if (copy_from_user(buf, user_buffer, buf_size))
1121                 return -EFAULT;
1122
1123         buf[buf_size] = '\0';
1124
1125         if (memcmp(buf, "connect ", 8) == 0) {
1126                 ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1127                 if (ret == -EINVAL)
1128                         return ret;
1129
1130                 if (listen_chan) {
1131                         l2cap_chan_close(listen_chan, 0);
1132                         l2cap_chan_put(listen_chan);
1133                         listen_chan = NULL;
1134                 }
1135
1136                 if (conn) {
1137                         struct lowpan_peer *peer;
1138
1139                         if (!is_bt_6lowpan(conn->hcon))
1140                                 return -EINVAL;
1141
1142                         peer = lookup_peer(conn);
1143                         if (peer) {
1144                                 BT_DBG("6LoWPAN connection already exists");
1145                                 return -EALREADY;
1146                         }
1147
1148                         BT_DBG("conn %p dst %pMR type %d user %d", conn,
1149                                &conn->hcon->dst, conn->hcon->dst_type,
1150                                addr_type);
1151                 }
1152
1153                 ret = bt_6lowpan_connect(&addr, addr_type);
1154                 if (ret < 0)
1155                         return ret;
1156
1157                 return count;
1158         }
1159
1160         if (memcmp(buf, "disconnect ", 11) == 0) {
1161                 ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
1162                 if (ret < 0)
1163                         return ret;
1164
1165                 ret = bt_6lowpan_disconnect(conn, addr_type);
1166                 if (ret < 0)
1167                         return ret;
1168
1169                 return count;
1170         }
1171
1172         return count;
1173 }
1174
1175 static int lowpan_control_show(struct seq_file *f, void *ptr)
1176 {
1177         struct lowpan_btle_dev *entry;
1178         struct lowpan_peer *peer;
1179
1180         spin_lock(&devices_lock);
1181
1182         list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1183                 list_for_each_entry(peer, &entry->peers, list)
1184                         seq_printf(f, "%pMR (type %u)\n",
1185                                    &peer->chan->dst, peer->chan->dst_type);
1186         }
1187
1188         spin_unlock(&devices_lock);
1189
1190         return 0;
1191 }
1192
1193 static int lowpan_control_open(struct inode *inode, struct file *file)
1194 {
1195         return single_open(file, lowpan_control_show, inode->i_private);
1196 }
1197
1198 static const struct file_operations lowpan_control_fops = {
1199         .open           = lowpan_control_open,
1200         .read           = seq_read,
1201         .write          = lowpan_control_write,
1202         .llseek         = seq_lseek,
1203         .release        = single_release,
1204 };
1205
1206 static void disconnect_devices(void)
1207 {
1208         struct lowpan_btle_dev *entry, *tmp, *new_dev;
1209         struct list_head devices;
1210
1211         INIT_LIST_HEAD(&devices);
1212
1213         /* We make a separate list of devices because the unregister_netdev()
1214          * will call device_event() which will also want to modify the same
1215          * devices list.
1216          */
1217
1218         rcu_read_lock();
1219
1220         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1221                 new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
1222                 if (!new_dev)
1223                         break;
1224
1225                 new_dev->netdev = entry->netdev;
1226                 INIT_LIST_HEAD(&new_dev->list);
1227
1228                 list_add_rcu(&new_dev->list, &devices);
1229         }
1230
1231         rcu_read_unlock();
1232
1233         list_for_each_entry_safe(entry, tmp, &devices, list) {
1234                 ifdown(entry->netdev);
1235                 BT_DBG("Unregistering netdev %s %p",
1236                        entry->netdev->name, entry->netdev);
1237                 lowpan_unregister_netdev(entry->netdev);
1238                 kfree(entry);
1239         }
1240 }
1241
1242 static int device_event(struct notifier_block *unused,
1243                         unsigned long event, void *ptr)
1244 {
1245         struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
1246         struct lowpan_btle_dev *entry;
1247
1248         if (netdev->type != ARPHRD_6LOWPAN)
1249                 return NOTIFY_DONE;
1250
1251         switch (event) {
1252         case NETDEV_UNREGISTER:
1253                 spin_lock(&devices_lock);
1254                 list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1255                         if (entry->netdev == netdev) {
1256                                 BT_DBG("Unregistered netdev %s %p",
1257                                        netdev->name, netdev);
1258                                 list_del(&entry->list);
1259                                 break;
1260                         }
1261                 }
1262                 spin_unlock(&devices_lock);
1263                 break;
1264         }
1265
1266         return NOTIFY_DONE;
1267 }
1268
1269 static struct notifier_block bt_6lowpan_dev_notifier = {
1270         .notifier_call = device_event,
1271 };
1272
1273 static int __init bt_6lowpan_init(void)
1274 {
1275         lowpan_enable_debugfs = debugfs_create_file_unsafe("6lowpan_enable",
1276                                                            0644, bt_debugfs,
1277                                                            NULL,
1278                                                            &lowpan_enable_fops);
1279         lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1280                                                      bt_debugfs, NULL,
1281                                                      &lowpan_control_fops);
1282
1283         return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1284 }
1285
1286 static void __exit bt_6lowpan_exit(void)
1287 {
1288         debugfs_remove(lowpan_enable_debugfs);
1289         debugfs_remove(lowpan_control_debugfs);
1290
1291         if (listen_chan) {
1292                 l2cap_chan_close(listen_chan, 0);
1293                 l2cap_chan_put(listen_chan);
1294         }
1295
1296         disconnect_devices();
1297
1298         unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1299 }
1300
1301 module_init(bt_6lowpan_init);
1302 module_exit(bt_6lowpan_exit);
1303
1304 MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1305 MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1306 MODULE_VERSION(VERSION);
1307 MODULE_LICENSE("GPL");