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 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 const struct net_device_ops netdev_ops = {
 576         .ndo_start_xmit         = bt_xmit,
 577 };
 578
 579 static const struct header_ops header_ops = {
 580         .create = header_create,
 581 };
 582
 583 static void netdev_setup(struct net_device *dev)
 584 {
 585         dev->hard_header_len    = 0;
 586         dev->needed_tailroom    = 0;
 587         dev->flags              = IFF_RUNNING | IFF_MULTICAST;
 588         dev->watchdog_timeo     = 0;
 589         dev->tx_queue_len       = DEFAULT_TX_QUEUE_LEN;
 590
 591         dev->netdev_ops         = &netdev_ops;
 592         dev->header_ops         = &header_ops;
 593         dev->needs_free_netdev  = true;
 594 }
 595
 596 static struct device_type bt_type = {
 597         .name   = "bluetooth",
 598 };
 599
 600 static void ifup(struct net_device *netdev)
 601 {
 602         int err;
 603
 604         rtnl_lock();
 605         err = dev_open(netdev, NULL);
 606         if (err < 0)
 607                 BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
 608         rtnl_unlock();
 609 }
 610
 611 static void ifdown(struct net_device *netdev)
 612 {
 613         rtnl_lock();
 614         dev_close(netdev);
 615         rtnl_unlock();
 616 }
 617
 618 static void do_notify_peers(struct work_struct *work)
 619 {
 620         struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_dev,
 621                                                    notify_peers.work);
 622
 623         netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
 624 }
 625
 626 static bool is_bt_6lowpan(struct hci_conn *hcon)
 627 {
 628         if (hcon->type != LE_LINK)
 629                 return false;
 630
 631         if (!enable_6lowpan)
 632                 return false;
 633
 634         return true;
 635 }
 636
 637 static struct l2cap_chan *chan_create(void)
 638 {
 639         struct l2cap_chan *chan;
 640
 641         chan = l2cap_chan_create();
 642         if (!chan)
 643                 return NULL;
 644
 645         l2cap_chan_set_defaults(chan);
 646
 647         chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
 648         chan->mode = L2CAP_MODE_LE_FLOWCTL;
 649         chan->imtu = 1280;
 650
 651         return chan;
 652 }
 653
 654 static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
 655                                         struct lowpan_btle_dev *dev,
 656                                         bool new_netdev)
 657 {
 658         struct lowpan_peer *peer;
 659
 660         peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
 661         if (!peer)
 662                 return NULL;
 663
 664         peer->chan = chan;
 665         memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
 666
 667         baswap((void *)peer->lladdr, &chan->dst);
 668
 669         lowpan_iphc_uncompress_eui48_lladdr(&peer->peer_addr, peer->lladdr);
 670
 671         spin_lock(&devices_lock);
 672         INIT_LIST_HEAD(&peer->list);
 673         peer_add(dev, peer);
 674         spin_unlock(&devices_lock);
 675
 676         /* Notifying peers about us needs to be done without locks held */
 677         if (new_netdev)
 678                 INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
 679         schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
 680
 681         return peer->chan;
 682 }
 683
 684 static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
 685 {
 686         struct net_device *netdev;
 687         int err = 0;
 688
 689         netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
 690                               IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
 691                               netdev_setup);
 692         if (!netdev)
 693                 return -ENOMEM;
 694
 695         netdev->addr_assign_type = NET_ADDR_PERM;
 696         baswap((void *)netdev->dev_addr, &chan->src);
 697
 698         netdev->netdev_ops = &netdev_ops;
 699         SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
 700         SET_NETDEV_DEVTYPE(netdev, &bt_type);
 701
 702         *dev = lowpan_btle_dev(netdev);
 703         (*dev)->netdev = netdev;
 704         (*dev)->hdev = chan->conn->hcon->hdev;
 705         INIT_LIST_HEAD(&(*dev)->peers);
 706
 707         spin_lock(&devices_lock);
 708         INIT_LIST_HEAD(&(*dev)->list);
 709         list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
 710         spin_unlock(&devices_lock);
 711
 712         err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
 713         if (err < 0) {
 714                 BT_INFO("register_netdev failed %d", err);
 715                 spin_lock(&devices_lock);
 716                 list_del_rcu(&(*dev)->list);
 717                 spin_unlock(&devices_lock);
 718                 free_netdev(netdev);
 719                 goto out;
 720         }
 721
 722         BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
 723                netdev->ifindex, &chan->dst, chan->dst_type,
 724                &chan->src, chan->src_type);
 725         set_bit(__LINK_STATE_PRESENT, &netdev->state);
 726
 727         return 0;
 728
 729 out:
 730         return err;
 731 }
 732
 733 static inline void chan_ready_cb(struct l2cap_chan *chan)
 734 {
 735         struct lowpan_btle_dev *dev;
 736         bool new_netdev = false;
 737
 738         dev = lookup_dev(chan->conn);
 739
 740         BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
 741
 742         if (!dev) {
 743                 if (setup_netdev(chan, &dev) < 0) {
 744                         l2cap_chan_del(chan, -ENOENT);
 745                         return;
 746                 }
 747                 new_netdev = true;
 748         }
 749
 750         if (!try_module_get(THIS_MODULE))
 751                 return;
 752
 753         add_peer_chan(chan, dev, new_netdev);
 754         ifup(dev->netdev);
 755 }
 756
 757 static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
 758 {
 759         struct l2cap_chan *chan;
 760
 761         chan = chan_create();
 762         if (!chan)
 763                 return NULL;
 764
 765         chan->ops = pchan->ops;
 766
 767         BT_DBG("chan %p pchan %p", chan, pchan);
 768
 769         return chan;
 770 }
 771
 772 static void delete_netdev(struct work_struct *work)
 773 {
 774         struct lowpan_btle_dev *entry = container_of(work,
 775                                                      struct lowpan_btle_dev,
 776                                                      delete_netdev);
 777
 778         lowpan_unregister_netdev(entry->netdev);
 779
 780         /* The entry pointer is deleted by the netdev destructor. */
 781 }
 782
 783 static void chan_close_cb(struct l2cap_chan *chan)
 784 {
 785         struct lowpan_btle_dev *entry;
 786         struct lowpan_btle_dev *dev = NULL;
 787         struct lowpan_peer *peer;
 788         int err = -ENOENT;
 789         bool last = false, remove = true;
 790
 791         BT_DBG("chan %p conn %p", chan, chan->conn);
 792
 793         if (chan->conn && chan->conn->hcon) {
 794                 if (!is_bt_6lowpan(chan->conn->hcon))
 795                         return;
 796
 797                 /* If conn is set, then the netdev is also there and we should
 798                  * not remove it.
 799                  */
 800                 remove = false;
 801         }
 802
 803         spin_lock(&devices_lock);
 804
 805         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 806                 dev = lowpan_btle_dev(entry->netdev);
 807                 peer = __peer_lookup_chan(dev, chan);
 808                 if (peer) {
 809                         last = peer_del(dev, peer);
 810                         err = 0;
 811
 812                         BT_DBG("dev %p removing %speer %p", dev,
 813                                last ? "last " : "1 ", peer);
 814                         BT_DBG("chan %p orig refcnt %d", chan,
 815                                kref_read(&chan->kref));
 816
 817                         l2cap_chan_put(chan);
 818                         break;
 819                 }
 820         }
 821
 822         if (!err && last && dev && !atomic_read(&dev->peer_count)) {
 823                 spin_unlock(&devices_lock);
 824
 825                 cancel_delayed_work_sync(&dev->notify_peers);
 826
 827                 ifdown(dev->netdev);
 828
 829                 if (remove) {
 830                         INIT_WORK(&entry->delete_netdev, delete_netdev);
 831                         schedule_work(&entry->delete_netdev);
 832                 }
 833         } else {
 834                 spin_unlock(&devices_lock);
 835         }
 836
 837         return;
 838 }
 839
 840 static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
 841 {
 842         BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
 843                state_to_string(state), err);
 844 }
 845
 846 static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
 847                                          unsigned long hdr_len,
 848                                          unsigned long len, int nb)
 849 {
 850         /* Note that we must allocate using GFP_ATOMIC here as
 851          * this function is called originally from netdev hard xmit
 852          * function in atomic context.
 853          */
 854         return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
 855 }
 856
 857 static void chan_suspend_cb(struct l2cap_chan *chan)
 858 {
 859         struct lowpan_btle_dev *dev;
 860
 861         BT_DBG("chan %p suspend", chan);
 862
 863         dev = lookup_dev(chan->conn);
 864         if (!dev || !dev->netdev)
 865                 return;
 866
 867         netif_stop_queue(dev->netdev);
 868 }
 869
 870 static void chan_resume_cb(struct l2cap_chan *chan)
 871 {
 872         struct lowpan_btle_dev *dev;
 873
 874         BT_DBG("chan %p resume", chan);
 875
 876         dev = lookup_dev(chan->conn);
 877         if (!dev || !dev->netdev)
 878                 return;
 879
 880         netif_wake_queue(dev->netdev);
 881 }
 882
 883 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
 884 {
 885         return L2CAP_CONN_TIMEOUT;
 886 }
 887
 888 static const struct l2cap_ops bt_6lowpan_chan_ops = {
 889         .name                   = "L2CAP 6LoWPAN channel",
 890         .new_connection         = chan_new_conn_cb,
 891         .recv                   = chan_recv_cb,
 892         .close                  = chan_close_cb,
 893         .state_change           = chan_state_change_cb,
 894         .ready                  = chan_ready_cb,
 895         .resume                 = chan_resume_cb,
 896         .suspend                = chan_suspend_cb,
 897         .get_sndtimeo           = chan_get_sndtimeo_cb,
 898         .alloc_skb              = chan_alloc_skb_cb,
 899
 900         .teardown               = l2cap_chan_no_teardown,
 901         .defer                  = l2cap_chan_no_defer,
 902         .set_shutdown           = l2cap_chan_no_set_shutdown,
 903 };
 904
 905 static inline __u8 bdaddr_type(__u8 type)
 906 {
 907         if (type == ADDR_LE_DEV_PUBLIC)
 908                 return BDADDR_LE_PUBLIC;
 909         else
 910                 return BDADDR_LE_RANDOM;
 911 }
 912
 913 static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
 914 {
 915         struct l2cap_chan *chan;
 916         int err;
 917
 918         chan = chan_create();
 919         if (!chan)
 920                 return -EINVAL;
 921
 922         chan->ops = &bt_6lowpan_chan_ops;
 923
 924         err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
 925                                  addr, dst_type);
 926
 927         BT_DBG("chan %p err %d", chan, err);
 928         if (err < 0)
 929                 l2cap_chan_put(chan);
 930
 931         return err;
 932 }
 933
 934 static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
 935 {
 936         struct lowpan_peer *peer;
 937
 938         BT_DBG("conn %p dst type %d", conn, dst_type);
 939
 940         peer = lookup_peer(conn);
 941         if (!peer)
 942                 return -ENOENT;
 943
 944         BT_DBG("peer %p chan %p", peer, peer->chan);
 945
 946         l2cap_chan_close(peer->chan, ENOENT);
 947
 948         return 0;
 949 }
 950
 951 static struct l2cap_chan *bt_6lowpan_listen(void)
 952 {
 953         bdaddr_t *addr = BDADDR_ANY;
 954         struct l2cap_chan *chan;
 955         int err;
 956
 957         if (!enable_6lowpan)
 958                 return NULL;
 959
 960         chan = chan_create();
 961         if (!chan)
 962                 return NULL;
 963
 964         chan->ops = &bt_6lowpan_chan_ops;
 965         chan->state = BT_LISTEN;
 966         chan->src_type = BDADDR_LE_PUBLIC;
 967
 968         atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
 969
 970         BT_DBG("chan %p src type %d", chan, chan->src_type);
 971
 972         err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
 973         if (err) {
 974                 l2cap_chan_put(chan);
 975                 BT_ERR("psm cannot be added err %d", err);
 976                 return NULL;
 977         }
 978
 979         return chan;
 980 }
 981
 982 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
 983                           struct l2cap_conn **conn)
 984 {
 985         struct hci_conn *hcon;
 986         struct hci_dev *hdev;
 987         int n;
 988
 989         n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
 990                    &addr->b[5], &addr->b[4], &addr->b[3],
 991                    &addr->b[2], &addr->b[1], &addr->b[0],
 992                    addr_type);
 993
 994         if (n < 7)
 995                 return -EINVAL;
 996
 997         /* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
 998         hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
 999         if (!hdev)
1000                 return -ENOENT;
1001
1002         hci_dev_lock(hdev);
1003         hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
1004         hci_dev_unlock(hdev);
1005
1006         if (!hcon)
1007                 return -ENOENT;
1008
1009         *conn = (struct l2cap_conn *)hcon->l2cap_data;
1010
1011         BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);
1012
1013         return 0;
1014 }
1015
1016 static void disconnect_all_peers(void)
1017 {
1018         struct lowpan_btle_dev *entry;
1019         struct lowpan_peer *peer, *tmp_peer, *new_peer;
1020         struct list_head peers;
1021
1022         INIT_LIST_HEAD(&peers);
1023
1024         /* We make a separate list of peers as the close_cb() will
1025          * modify the device peers list so it is better not to mess
1026          * with the same list at the same time.
1027          */
1028
1029         rcu_read_lock();
1030
1031         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1032                 list_for_each_entry_rcu(peer, &entry->peers, list) {
1033                         new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1034                         if (!new_peer)
1035                                 break;
1036
1037                         new_peer->chan = peer->chan;
1038                         INIT_LIST_HEAD(&new_peer->list);
1039
1040                         list_add(&new_peer->list, &peers);
1041                 }
1042         }
1043
1044         rcu_read_unlock();
1045
1046         spin_lock(&devices_lock);
1047         list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1048                 l2cap_chan_close(peer->chan, ENOENT);
1049
1050                 list_del_rcu(&peer->list);
1051                 kfree_rcu(peer, rcu);
1052         }
1053         spin_unlock(&devices_lock);
1054 }
1055
1056 struct set_enable {
1057         struct work_struct work;
1058         bool flag;
1059 };
1060
1061 static void do_enable_set(struct work_struct *work)
1062 {
1063         struct set_enable *set_enable = container_of(work,
1064                                                      struct set_enable, work);
1065
1066         if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1067                 /* Disconnect existing connections if 6lowpan is
1068                  * disabled
1069                  */
1070                 disconnect_all_peers();
1071
1072         enable_6lowpan = set_enable->flag;
1073
1074         mutex_lock(&set_lock);
1075         if (listen_chan) {
1076                 l2cap_chan_close(listen_chan, 0);
1077                 l2cap_chan_put(listen_chan);
1078         }
1079
1080         listen_chan = bt_6lowpan_listen();
1081         mutex_unlock(&set_lock);
1082
1083         kfree(set_enable);
1084 }
1085
1086 static int lowpan_enable_set(void *data, u64 val)
1087 {
1088         struct set_enable *set_enable;
1089
1090         set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1091         if (!set_enable)
1092                 return -ENOMEM;
1093
1094         set_enable->flag = !!val;
1095         INIT_WORK(&set_enable->work, do_enable_set);
1096
1097         schedule_work(&set_enable->work);
1098
1099         return 0;
1100 }
1101
1102 static int lowpan_enable_get(void *data, u64 *val)
1103 {
1104         *val = enable_6lowpan;
1105         return 0;
1106 }
1107
1108 DEFINE_DEBUGFS_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1109                          lowpan_enable_set, "%llu\n");
1110
1111 static ssize_t lowpan_control_write(struct file *fp,
1112                                     const char __user *user_buffer,
1113                                     size_t count,
1114                                     loff_t *position)
1115 {
1116         char buf[32];
1117         size_t buf_size = min(count, sizeof(buf) - 1);
1118         int ret;
1119         bdaddr_t addr;
1120         u8 addr_type;
1121         struct l2cap_conn *conn = NULL;
1122
1123         if (copy_from_user(buf, user_buffer, buf_size))
1124                 return -EFAULT;
1125
1126         buf[buf_size] = '\0';
1127
1128         if (memcmp(buf, "connect ", 8) == 0) {
1129                 ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1130                 if (ret == -EINVAL)
1131                         return ret;
1132
1133                 mutex_lock(&set_lock);
1134                 if (listen_chan) {
1135                         l2cap_chan_close(listen_chan, 0);
1136                         l2cap_chan_put(listen_chan);
1137                         listen_chan = NULL;
1138                 }
1139                 mutex_unlock(&set_lock);
1140
1141                 if (conn) {
1142                         struct lowpan_peer *peer;
1143
1144                         if (!is_bt_6lowpan(conn->hcon))
1145                                 return -EINVAL;
1146
1147                         peer = lookup_peer(conn);
1148                         if (peer) {
1149                                 BT_DBG("6LoWPAN connection already exists");
1150                                 return -EALREADY;
1151                         }
1152
1153                         BT_DBG("conn %p dst %pMR type %d user %d", conn,
1154                                &conn->hcon->dst, conn->hcon->dst_type,
1155                                addr_type);
1156                 }
1157
1158                 ret = bt_6lowpan_connect(&addr, addr_type);
1159                 if (ret < 0)
1160                         return ret;
1161
1162                 return count;
1163         }
1164
1165         if (memcmp(buf, "disconnect ", 11) == 0) {
1166                 ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
1167                 if (ret < 0)
1168                         return ret;
1169
1170                 ret = bt_6lowpan_disconnect(conn, addr_type);
1171                 if (ret < 0)
1172                         return ret;
1173
1174                 return count;
1175         }
1176
1177         return count;
1178 }
1179
1180 static int lowpan_control_show(struct seq_file *f, void *ptr)
1181 {
1182         struct lowpan_btle_dev *entry;
1183         struct lowpan_peer *peer;
1184
1185         spin_lock(&devices_lock);
1186
1187         list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1188                 list_for_each_entry(peer, &entry->peers, list)
1189                         seq_printf(f, "%pMR (type %u)\n",
1190                                    &peer->chan->dst, peer->chan->dst_type);
1191         }
1192
1193         spin_unlock(&devices_lock);
1194
1195         return 0;
1196 }
1197
1198 static int lowpan_control_open(struct inode *inode, struct file *file)
1199 {
1200         return single_open(file, lowpan_control_show, inode->i_private);
1201 }
1202
1203 static const struct file_operations lowpan_control_fops = {
1204         .open           = lowpan_control_open,
1205         .read           = seq_read,
1206         .write          = lowpan_control_write,
1207         .llseek         = seq_lseek,
1208         .release        = single_release,
1209 };
1210
1211 static void disconnect_devices(void)
1212 {
1213         struct lowpan_btle_dev *entry, *tmp, *new_dev;
1214         struct list_head devices;
1215
1216         INIT_LIST_HEAD(&devices);
1217
1218         /* We make a separate list of devices because the unregister_netdev()
1219          * will call device_event() which will also want to modify the same
1220          * devices list.
1221          */
1222
1223         rcu_read_lock();
1224
1225         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1226                 new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
1227                 if (!new_dev)
1228                         break;
1229
1230                 new_dev->netdev = entry->netdev;
1231                 INIT_LIST_HEAD(&new_dev->list);
1232
1233                 list_add_rcu(&new_dev->list, &devices);
1234         }
1235
1236         rcu_read_unlock();
1237
1238         list_for_each_entry_safe(entry, tmp, &devices, list) {
1239                 ifdown(entry->netdev);
1240                 BT_DBG("Unregistering netdev %s %p",
1241                        entry->netdev->name, entry->netdev);
1242                 lowpan_unregister_netdev(entry->netdev);
1243                 kfree(entry);
1244         }
1245 }
1246
1247 static int device_event(struct notifier_block *unused,
1248                         unsigned long event, void *ptr)
1249 {
1250         struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
1251         struct lowpan_btle_dev *entry;
1252
1253         if (netdev->type != ARPHRD_6LOWPAN)
1254                 return NOTIFY_DONE;
1255
1256         switch (event) {
1257         case NETDEV_UNREGISTER:
1258                 spin_lock(&devices_lock);
1259                 list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1260                         if (entry->netdev == netdev) {
1261                                 BT_DBG("Unregistered netdev %s %p",
1262                                        netdev->name, netdev);
1263                                 list_del(&entry->list);
1264                                 break;
1265                         }
1266                 }
1267                 spin_unlock(&devices_lock);
1268                 break;
1269         }
1270
1271         return NOTIFY_DONE;
1272 }
1273
1274 static struct notifier_block bt_6lowpan_dev_notifier = {
1275         .notifier_call = device_event,
1276 };
1277
1278 static int __init bt_6lowpan_init(void)
1279 {
1280         lowpan_enable_debugfs = debugfs_create_file_unsafe("6lowpan_enable",
1281                                                            0644, bt_debugfs,
1282                                                            NULL,
1283                                                            &lowpan_enable_fops);
1284         lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1285                                                      bt_debugfs, NULL,
1286                                                      &lowpan_control_fops);
1287
1288         return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1289 }
1290
1291 static void __exit bt_6lowpan_exit(void)
1292 {
1293         debugfs_remove(lowpan_enable_debugfs);
1294         debugfs_remove(lowpan_control_debugfs);
1295
1296         if (listen_chan) {
1297                 l2cap_chan_close(listen_chan, 0);
1298                 l2cap_chan_put(listen_chan);
1299         }
1300
1301         disconnect_devices();
1302
1303         unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1304 }
1305
1306 module_init(bt_6lowpan_init);
1307 module_exit(bt_6lowpan_exit);
1308
1309 MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1310 MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1311 MODULE_VERSION(VERSION);
1312 MODULE_LICENSE("GPL");