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         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 int bt_dev_init(struct net_device *dev)
 575 {
 576         netdev_lockdep_set_classes(dev);
 577
 578         return 0;
 579 }
 580
 581 static const struct net_device_ops netdev_ops = {
 582         .ndo_init               = bt_dev_init,
 583         .ndo_start_xmit         = bt_xmit,
 584 };
 585
 586 static const struct header_ops header_ops = {
 587         .create = header_create,
 588 };
 589
 590 static void netdev_setup(struct net_device *dev)
 591 {
 592         dev->hard_header_len    = 0;
 593         dev->needed_tailroom    = 0;
 594         dev->flags              = IFF_RUNNING | IFF_MULTICAST;
 595         dev->watchdog_timeo     = 0;
 596         dev->tx_queue_len       = DEFAULT_TX_QUEUE_LEN;
 597
 598         dev->netdev_ops         = &netdev_ops;
 599         dev->header_ops         = &header_ops;
 600         dev->needs_free_netdev  = true;
 601 }
 602
 603 static struct device_type bt_type = {
 604         .name   = "bluetooth",
 605 };
 606
 607 static void ifup(struct net_device *netdev)
 608 {
 609         int err;
 610
 611         rtnl_lock();
 612         err = dev_open(netdev, NULL);
 613         if (err < 0)
 614                 BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
 615         rtnl_unlock();
 616 }
 617
 618 static void ifdown(struct net_device *netdev)
 619 {
 620         rtnl_lock();
 621         dev_close(netdev);
 622         rtnl_unlock();
 623 }
 624
 625 static void do_notify_peers(struct work_struct *work)
 626 {
 627         struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_dev,
 628                                                    notify_peers.work);
 629
 630         netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
 631 }
 632
 633 static bool is_bt_6lowpan(struct hci_conn *hcon)
 634 {
 635         if (hcon->type != LE_LINK)
 636                 return false;
 637
 638         if (!enable_6lowpan)
 639                 return false;
 640
 641         return true;
 642 }
 643
 644 static struct l2cap_chan *chan_create(void)
 645 {
 646         struct l2cap_chan *chan;
 647
 648         chan = l2cap_chan_create();
 649         if (!chan)
 650                 return NULL;
 651
 652         l2cap_chan_set_defaults(chan);
 653
 654         chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
 655         chan->mode = L2CAP_MODE_LE_FLOWCTL;
 656         chan->imtu = 1280;
 657
 658         return chan;
 659 }
 660
 661 static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
 662                                         struct lowpan_btle_dev *dev,
 663                                         bool new_netdev)
 664 {
 665         struct lowpan_peer *peer;
 666
 667         peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
 668         if (!peer)
 669                 return NULL;
 670
 671         peer->chan = chan;
 672         memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
 673
 674         baswap((void *)peer->lladdr, &chan->dst);
 675
 676         lowpan_iphc_uncompress_eui48_lladdr(&peer->peer_addr, peer->lladdr);
 677
 678         spin_lock(&devices_lock);
 679         INIT_LIST_HEAD(&peer->list);
 680         peer_add(dev, peer);
 681         spin_unlock(&devices_lock);
 682
 683         /* Notifying peers about us needs to be done without locks held */
 684         if (new_netdev)
 685                 INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
 686         schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
 687
 688         return peer->chan;
 689 }
 690
 691 static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
 692 {
 693         struct net_device *netdev;
 694         int err = 0;
 695
 696         netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
 697                               IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
 698                               netdev_setup);
 699         if (!netdev)
 700                 return -ENOMEM;
 701
 702         netdev->addr_assign_type = NET_ADDR_PERM;
 703         baswap((void *)netdev->dev_addr, &chan->src);
 704
 705         netdev->netdev_ops = &netdev_ops;
 706         SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
 707         SET_NETDEV_DEVTYPE(netdev, &bt_type);
 708
 709         *dev = lowpan_btle_dev(netdev);
 710         (*dev)->netdev = netdev;
 711         (*dev)->hdev = chan->conn->hcon->hdev;
 712         INIT_LIST_HEAD(&(*dev)->peers);
 713
 714         spin_lock(&devices_lock);
 715         INIT_LIST_HEAD(&(*dev)->list);
 716         list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
 717         spin_unlock(&devices_lock);
 718
 719         err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
 720         if (err < 0) {
 721                 BT_INFO("register_netdev failed %d", err);
 722                 spin_lock(&devices_lock);
 723                 list_del_rcu(&(*dev)->list);
 724                 spin_unlock(&devices_lock);
 725                 free_netdev(netdev);
 726                 goto out;
 727         }
 728
 729         BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
 730                netdev->ifindex, &chan->dst, chan->dst_type,
 731                &chan->src, chan->src_type);
 732         set_bit(__LINK_STATE_PRESENT, &netdev->state);
 733
 734         return 0;
 735
 736 out:
 737         return err;
 738 }
 739
 740 static inline void chan_ready_cb(struct l2cap_chan *chan)
 741 {
 742         struct lowpan_btle_dev *dev;
 743         bool new_netdev = false;
 744
 745         dev = lookup_dev(chan->conn);
 746
 747         BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
 748
 749         if (!dev) {
 750                 if (setup_netdev(chan, &dev) < 0) {
 751                         l2cap_chan_del(chan, -ENOENT);
 752                         return;
 753                 }
 754                 new_netdev = true;
 755         }
 756
 757         if (!try_module_get(THIS_MODULE))
 758                 return;
 759
 760         add_peer_chan(chan, dev, new_netdev);
 761         ifup(dev->netdev);
 762 }
 763
 764 static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
 765 {
 766         struct l2cap_chan *chan;
 767
 768         chan = chan_create();
 769         if (!chan)
 770                 return NULL;
 771
 772         chan->ops = pchan->ops;
 773
 774         BT_DBG("chan %p pchan %p", chan, pchan);
 775
 776         return chan;
 777 }
 778
 779 static void delete_netdev(struct work_struct *work)
 780 {
 781         struct lowpan_btle_dev *entry = container_of(work,
 782                                                      struct lowpan_btle_dev,
 783                                                      delete_netdev);
 784
 785         lowpan_unregister_netdev(entry->netdev);
 786
 787         /* The entry pointer is deleted by the netdev destructor. */
 788 }
 789
 790 static void chan_close_cb(struct l2cap_chan *chan)
 791 {
 792         struct lowpan_btle_dev *entry;
 793         struct lowpan_btle_dev *dev = NULL;
 794         struct lowpan_peer *peer;
 795         int err = -ENOENT;
 796         bool last = false, remove = true;
 797
 798         BT_DBG("chan %p conn %p", chan, chan->conn);
 799
 800         if (chan->conn && chan->conn->hcon) {
 801                 if (!is_bt_6lowpan(chan->conn->hcon))
 802                         return;
 803
 804                 /* If conn is set, then the netdev is also there and we should
 805                  * not remove it.
 806                  */
 807                 remove = false;
 808         }
 809
 810         spin_lock(&devices_lock);
 811
 812         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 813                 dev = lowpan_btle_dev(entry->netdev);
 814                 peer = __peer_lookup_chan(dev, chan);
 815                 if (peer) {
 816                         last = peer_del(dev, peer);
 817                         err = 0;
 818
 819                         BT_DBG("dev %p removing %speer %p", dev,
 820                                last ? "last " : "1 ", peer);
 821                         BT_DBG("chan %p orig refcnt %d", chan,
 822                                kref_read(&chan->kref));
 823
 824                         l2cap_chan_put(chan);
 825                         break;
 826                 }
 827         }
 828
 829         if (!err && last && dev && !atomic_read(&dev->peer_count)) {
 830                 spin_unlock(&devices_lock);
 831
 832                 cancel_delayed_work_sync(&dev->notify_peers);
 833
 834                 ifdown(dev->netdev);
 835
 836                 if (remove) {
 837                         INIT_WORK(&entry->delete_netdev, delete_netdev);
 838                         schedule_work(&entry->delete_netdev);
 839                 }
 840         } else {
 841                 spin_unlock(&devices_lock);
 842         }
 843 }
 844
 845 static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
 846 {
 847         BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
 848                state_to_string(state), err);
 849 }
 850
 851 static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
 852                                          unsigned long hdr_len,
 853                                          unsigned long len, int nb)
 854 {
 855         /* Note that we must allocate using GFP_ATOMIC here as
 856          * this function is called originally from netdev hard xmit
 857          * function in atomic context.
 858          */
 859         return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
 860 }
 861
 862 static void chan_suspend_cb(struct l2cap_chan *chan)
 863 {
 864         struct lowpan_btle_dev *dev;
 865
 866         BT_DBG("chan %p suspend", chan);
 867
 868         dev = lookup_dev(chan->conn);
 869         if (!dev || !dev->netdev)
 870                 return;
 871
 872         netif_stop_queue(dev->netdev);
 873 }
 874
 875 static void chan_resume_cb(struct l2cap_chan *chan)
 876 {
 877         struct lowpan_btle_dev *dev;
 878
 879         BT_DBG("chan %p resume", chan);
 880
 881         dev = lookup_dev(chan->conn);
 882         if (!dev || !dev->netdev)
 883                 return;
 884
 885         netif_wake_queue(dev->netdev);
 886 }
 887
 888 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
 889 {
 890         return L2CAP_CONN_TIMEOUT;
 891 }
 892
 893 static const struct l2cap_ops bt_6lowpan_chan_ops = {
 894         .name                   = "L2CAP 6LoWPAN channel",
 895         .new_connection         = chan_new_conn_cb,
 896         .recv                   = chan_recv_cb,
 897         .close                  = chan_close_cb,
 898         .state_change           = chan_state_change_cb,
 899         .ready                  = chan_ready_cb,
 900         .resume                 = chan_resume_cb,
 901         .suspend                = chan_suspend_cb,
 902         .get_sndtimeo           = chan_get_sndtimeo_cb,
 903         .alloc_skb              = chan_alloc_skb_cb,
 904
 905         .teardown               = l2cap_chan_no_teardown,
 906         .defer                  = l2cap_chan_no_defer,
 907         .set_shutdown           = l2cap_chan_no_set_shutdown,
 908 };
 909
 910 static inline __u8 bdaddr_type(__u8 type)
 911 {
 912         if (type == ADDR_LE_DEV_PUBLIC)
 913                 return BDADDR_LE_PUBLIC;
 914         else
 915                 return BDADDR_LE_RANDOM;
 916 }
 917
 918 static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
 919 {
 920         struct l2cap_chan *chan;
 921         int err;
 922
 923         chan = chan_create();
 924         if (!chan)
 925                 return -EINVAL;
 926
 927         chan->ops = &bt_6lowpan_chan_ops;
 928
 929         err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
 930                                  addr, dst_type);
 931
 932         BT_DBG("chan %p err %d", chan, err);
 933         if (err < 0)
 934                 l2cap_chan_put(chan);
 935
 936         return err;
 937 }
 938
 939 static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
 940 {
 941         struct lowpan_peer *peer;
 942
 943         BT_DBG("conn %p dst type %d", conn, dst_type);
 944
 945         peer = lookup_peer(conn);
 946         if (!peer)
 947                 return -ENOENT;
 948
 949         BT_DBG("peer %p chan %p", peer, peer->chan);
 950
 951         l2cap_chan_close(peer->chan, ENOENT);
 952
 953         return 0;
 954 }
 955
 956 static struct l2cap_chan *bt_6lowpan_listen(void)
 957 {
 958         bdaddr_t *addr = BDADDR_ANY;
 959         struct l2cap_chan *chan;
 960         int err;
 961
 962         if (!enable_6lowpan)
 963                 return NULL;
 964
 965         chan = chan_create();
 966         if (!chan)
 967                 return NULL;
 968
 969         chan->ops = &bt_6lowpan_chan_ops;
 970         chan->state = BT_LISTEN;
 971         chan->src_type = BDADDR_LE_PUBLIC;
 972
 973         atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
 974
 975         BT_DBG("chan %p src type %d", chan, chan->src_type);
 976
 977         err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
 978         if (err) {
 979                 l2cap_chan_put(chan);
 980                 BT_ERR("psm cannot be added err %d", err);
 981                 return NULL;
 982         }
 983
 984         return chan;
 985 }
 986
 987 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
 988                           struct l2cap_conn **conn)
 989 {
 990         struct hci_conn *hcon;
 991         struct hci_dev *hdev;
 992         int n;
 993
 994         n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
 995                    &addr->b[5], &addr->b[4], &addr->b[3],
 996                    &addr->b[2], &addr->b[1], &addr->b[0],
 997                    addr_type);
 998
 999         if (n < 7)
1000                 return -EINVAL;
1001
1002         /* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
1003         hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
1004         if (!hdev)
1005                 return -ENOENT;
1006
1007         hci_dev_lock(hdev);
1008         hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
1009         hci_dev_unlock(hdev);
1010
1011         if (!hcon)
1012                 return -ENOENT;
1013
1014         *conn = (struct l2cap_conn *)hcon->l2cap_data;
1015
1016         BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);
1017
1018         return 0;
1019 }
1020
1021 static void disconnect_all_peers(void)
1022 {
1023         struct lowpan_btle_dev *entry;
1024         struct lowpan_peer *peer, *tmp_peer, *new_peer;
1025         struct list_head peers;
1026
1027         INIT_LIST_HEAD(&peers);
1028
1029         /* We make a separate list of peers as the close_cb() will
1030          * modify the device peers list so it is better not to mess
1031          * with the same list at the same time.
1032          */
1033
1034         rcu_read_lock();
1035
1036         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1037                 list_for_each_entry_rcu(peer, &entry->peers, list) {
1038                         new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1039                         if (!new_peer)
1040                                 break;
1041
1042                         new_peer->chan = peer->chan;
1043                         INIT_LIST_HEAD(&new_peer->list);
1044
1045                         list_add(&new_peer->list, &peers);
1046                 }
1047         }
1048
1049         rcu_read_unlock();
1050
1051         spin_lock(&devices_lock);
1052         list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1053                 l2cap_chan_close(peer->chan, ENOENT);
1054
1055                 list_del_rcu(&peer->list);
1056                 kfree_rcu(peer, rcu);
1057         }
1058         spin_unlock(&devices_lock);
1059 }
1060
1061 struct set_enable {
1062         struct work_struct work;
1063         bool flag;
1064 };
1065
1066 static void do_enable_set(struct work_struct *work)
1067 {
1068         struct set_enable *set_enable = container_of(work,
1069                                                      struct set_enable, work);
1070
1071         if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1072                 /* Disconnect existing connections if 6lowpan is
1073                  * disabled
1074                  */
1075                 disconnect_all_peers();
1076
1077         enable_6lowpan = set_enable->flag;
1078
1079         mutex_lock(&set_lock);
1080         if (listen_chan) {
1081                 l2cap_chan_close(listen_chan, 0);
1082                 l2cap_chan_put(listen_chan);
1083         }
1084
1085         listen_chan = bt_6lowpan_listen();
1086         mutex_unlock(&set_lock);
1087
1088         kfree(set_enable);
1089 }
1090
1091 static int lowpan_enable_set(void *data, u64 val)
1092 {
1093         struct set_enable *set_enable;
1094
1095         set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1096         if (!set_enable)
1097                 return -ENOMEM;
1098
1099         set_enable->flag = !!val;
1100         INIT_WORK(&set_enable->work, do_enable_set);
1101
1102         schedule_work(&set_enable->work);
1103
1104         return 0;
1105 }
1106
1107 static int lowpan_enable_get(void *data, u64 *val)
1108 {
1109         *val = enable_6lowpan;
1110         return 0;
1111 }
1112
1113 DEFINE_DEBUGFS_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1114                          lowpan_enable_set, "%llu\n");
1115
1116 static ssize_t lowpan_control_write(struct file *fp,
1117                                     const char __user *user_buffer,
1118                                     size_t count,
1119                                     loff_t *position)
1120 {
1121         char buf[32];
1122         size_t buf_size = min(count, sizeof(buf) - 1);
1123         int ret;
1124         bdaddr_t addr;
1125         u8 addr_type;
1126         struct l2cap_conn *conn = NULL;
1127
1128         if (copy_from_user(buf, user_buffer, buf_size))
1129                 return -EFAULT;
1130
1131         buf[buf_size] = '\0';
1132
1133         if (memcmp(buf, "connect ", 8) == 0) {
1134                 ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1135                 if (ret == -EINVAL)
1136                         return ret;
1137
1138                 mutex_lock(&set_lock);
1139                 if (listen_chan) {
1140                         l2cap_chan_close(listen_chan, 0);
1141                         l2cap_chan_put(listen_chan);
1142                         listen_chan = NULL;
1143                 }
1144                 mutex_unlock(&set_lock);
1145
1146                 if (conn) {
1147                         struct lowpan_peer *peer;
1148
1149                         if (!is_bt_6lowpan(conn->hcon))
1150                                 return -EINVAL;
1151
1152                         peer = lookup_peer(conn);
1153                         if (peer) {
1154                                 BT_DBG("6LoWPAN connection already exists");
1155                                 return -EALREADY;
1156                         }
1157
1158                         BT_DBG("conn %p dst %pMR type %d user %d", conn,
1159                                &conn->hcon->dst, conn->hcon->dst_type,
1160                                addr_type);
1161                 }
1162
1163                 ret = bt_6lowpan_connect(&addr, addr_type);
1164                 if (ret < 0)
1165                         return ret;
1166
1167                 return count;
1168         }
1169
1170         if (memcmp(buf, "disconnect ", 11) == 0) {
1171                 ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
1172                 if (ret < 0)
1173                         return ret;
1174
1175                 ret = bt_6lowpan_disconnect(conn, addr_type);
1176                 if (ret < 0)
1177                         return ret;
1178
1179                 return count;
1180         }
1181
1182         return count;
1183 }
1184
1185 static int lowpan_control_show(struct seq_file *f, void *ptr)
1186 {
1187         struct lowpan_btle_dev *entry;
1188         struct lowpan_peer *peer;
1189
1190         spin_lock(&devices_lock);
1191
1192         list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1193                 list_for_each_entry(peer, &entry->peers, list)
1194                         seq_printf(f, "%pMR (type %u)\n",
1195                                    &peer->chan->dst, peer->chan->dst_type);
1196         }
1197
1198         spin_unlock(&devices_lock);
1199
1200         return 0;
1201 }
1202
1203 static int lowpan_control_open(struct inode *inode, struct file *file)
1204 {
1205         return single_open(file, lowpan_control_show, inode->i_private);
1206 }
1207
1208 static const struct file_operations lowpan_control_fops = {
1209         .open           = lowpan_control_open,
1210         .read           = seq_read,
1211         .write          = lowpan_control_write,
1212         .llseek         = seq_lseek,
1213         .release        = single_release,
1214 };
1215
1216 static void disconnect_devices(void)
1217 {
1218         struct lowpan_btle_dev *entry, *tmp, *new_dev;
1219         struct list_head devices;
1220
1221         INIT_LIST_HEAD(&devices);
1222
1223         /* We make a separate list of devices because the unregister_netdev()
1224          * will call device_event() which will also want to modify the same
1225          * devices list.
1226          */
1227
1228         rcu_read_lock();
1229
1230         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1231                 new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
1232                 if (!new_dev)
1233                         break;
1234
1235                 new_dev->netdev = entry->netdev;
1236                 INIT_LIST_HEAD(&new_dev->list);
1237
1238                 list_add_rcu(&new_dev->list, &devices);
1239         }
1240
1241         rcu_read_unlock();
1242
1243         list_for_each_entry_safe(entry, tmp, &devices, list) {
1244                 ifdown(entry->netdev);
1245                 BT_DBG("Unregistering netdev %s %p",
1246                        entry->netdev->name, entry->netdev);
1247                 lowpan_unregister_netdev(entry->netdev);
1248                 kfree(entry);
1249         }
1250 }
1251
1252 static int device_event(struct notifier_block *unused,
1253                         unsigned long event, void *ptr)
1254 {
1255         struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
1256         struct lowpan_btle_dev *entry;
1257
1258         if (netdev->type != ARPHRD_6LOWPAN)
1259                 return NOTIFY_DONE;
1260
1261         switch (event) {
1262         case NETDEV_UNREGISTER:
1263                 spin_lock(&devices_lock);
1264                 list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1265                         if (entry->netdev == netdev) {
1266                                 BT_DBG("Unregistered netdev %s %p",
1267                                        netdev->name, netdev);
1268                                 list_del(&entry->list);
1269                                 break;
1270                         }
1271                 }
1272                 spin_unlock(&devices_lock);
1273                 break;
1274         }
1275
1276         return NOTIFY_DONE;
1277 }
1278
1279 static struct notifier_block bt_6lowpan_dev_notifier = {
1280         .notifier_call = device_event,
1281 };
1282
1283 static int __init bt_6lowpan_init(void)
1284 {
1285         lowpan_enable_debugfs = debugfs_create_file_unsafe("6lowpan_enable",
1286                                                            0644, bt_debugfs,
1287                                                            NULL,
1288                                                            &lowpan_enable_fops);
1289         lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1290                                                      bt_debugfs, NULL,
1291                                                      &lowpan_control_fops);
1292
1293         return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1294 }
1295
1296 static void __exit bt_6lowpan_exit(void)
1297 {
1298         debugfs_remove(lowpan_enable_debugfs);
1299         debugfs_remove(lowpan_control_debugfs);
1300
1301         if (listen_chan) {
1302                 l2cap_chan_close(listen_chan, 0);
1303                 l2cap_chan_put(listen_chan);
1304         }
1305
1306         disconnect_devices();
1307
1308         unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1309 }
1310
1311 module_init(bt_6lowpan_init);
1312 module_exit(bt_6lowpan_exit);
1313
1314 MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1315 MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1316 MODULE_VERSION(VERSION);
1317 MODULE_LICENSE("GPL");