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