net/bluetooth/6lowpan.c

   1 /*
   2    Copyright (c) 2013-2014 Intel Corp.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License version 2 and
   6    only version 2 as published by the Free Software Foundation.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12 */
  13
  14 #include <linux/if_arp.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/module.h>
  18 #include <linux/debugfs.h>
  19
  20 #include <net/ipv6.h>
  21 #include <net/ip6_route.h>
  22 #include <net/addrconf.h>
  23
  24 #include <net/bluetooth/bluetooth.h>
  25 #include <net/bluetooth/hci_core.h>
  26 #include <net/bluetooth/l2cap.h>
  27
  28 #include <net/6lowpan.h> /* for the compression support */
  29
  30 #define VERSION "0.1"
  31
  32 static struct dentry *lowpan_enable_debugfs;
  33 static struct dentry *lowpan_control_debugfs;
  34
  35 #define IFACE_NAME_TEMPLATE "bt%d"
  36
  37 struct skb_cb {
  38         struct in6_addr addr;
  39         struct in6_addr gw;
  40         struct l2cap_chan *chan;
  41         int status;
  42 };
  43 #define lowpan_cb(skb) ((struct skb_cb *)((skb)->cb))
  44
  45 /* The devices list contains those devices that we are acting
  46  * as a proxy. The BT 6LoWPAN device is a virtual device that
  47  * connects to the Bluetooth LE device. The real connection to
  48  * BT device is done via l2cap layer. There exists one
  49  * virtual device / one BT 6LoWPAN network (=hciX device).
  50  * The list contains struct lowpan_dev elements.
  51  */
  52 static LIST_HEAD(bt_6lowpan_devices);
  53 static DEFINE_SPINLOCK(devices_lock);
  54
  55 static bool enable_6lowpan;
  56
  57 /* We are listening incoming connections via this channel
  58  */
  59 static struct l2cap_chan *listen_chan;
  60
  61 struct lowpan_peer {
  62         struct list_head list;
  63         struct rcu_head rcu;
  64         struct l2cap_chan *chan;
  65
  66         /* peer addresses in various formats */
  67         unsigned char eui64_addr[EUI64_ADDR_LEN];
  68         struct in6_addr peer_addr;
  69 };
  70
  71 struct lowpan_dev {
  72         struct list_head list;
  73
  74         struct hci_dev *hdev;
  75         struct net_device *netdev;
  76         struct list_head peers;
  77         atomic_t peer_count; /* number of items in peers list */
  78
  79         struct work_struct delete_netdev;
  80         struct delayed_work notify_peers;
  81 };
  82
  83 static inline struct lowpan_dev *lowpan_dev(const struct net_device *netdev)
  84 {
  85         return (struct lowpan_dev *)lowpan_priv(netdev)->priv;
  86 }
  87
  88 static inline void peer_add(struct lowpan_dev *dev, struct lowpan_peer *peer)
  89 {
  90         list_add_rcu(&peer->list, &dev->peers);
  91         atomic_inc(&dev->peer_count);
  92 }
  93
  94 static inline bool peer_del(struct lowpan_dev *dev, struct lowpan_peer *peer)
  95 {
  96         list_del_rcu(&peer->list);
  97         kfree_rcu(peer, rcu);
  98
  99         module_put(THIS_MODULE);
 100
 101         if (atomic_dec_and_test(&dev->peer_count)) {
 102                 BT_DBG("last peer");
 103                 return true;
 104         }
 105
 106         return false;
 107 }
 108
 109 static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_dev *dev,
 110                                                  bdaddr_t *ba, __u8 type)
 111 {
 112         struct lowpan_peer *peer;
 113
 114         BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
 115                ba, type);
 116
 117         rcu_read_lock();
 118
 119         list_for_each_entry_rcu(peer, &dev->peers, list) {
 120                 BT_DBG("dst addr %pMR dst type %d",
 121                        &peer->chan->dst, peer->chan->dst_type);
 122
 123                 if (bacmp(&peer->chan->dst, ba))
 124                         continue;
 125
 126                 if (type == peer->chan->dst_type) {
 127                         rcu_read_unlock();
 128                         return peer;
 129                 }
 130         }
 131
 132         rcu_read_unlock();
 133
 134         return NULL;
 135 }
 136
 137 static inline struct lowpan_peer *__peer_lookup_chan(struct lowpan_dev *dev,
 138                                                      struct l2cap_chan *chan)
 139 {
 140         struct lowpan_peer *peer;
 141
 142         list_for_each_entry_rcu(peer, &dev->peers, list) {
 143                 if (peer->chan == chan)
 144                         return peer;
 145         }
 146
 147         return NULL;
 148 }
 149
 150 static inline struct lowpan_peer *__peer_lookup_conn(struct lowpan_dev *dev,
 151                                                      struct l2cap_conn *conn)
 152 {
 153         struct lowpan_peer *peer;
 154
 155         list_for_each_entry_rcu(peer, &dev->peers, list) {
 156                 if (peer->chan->conn == conn)
 157                         return peer;
 158         }
 159
 160         return NULL;
 161 }
 162
 163 static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_dev *dev,
 164                                                   struct in6_addr *daddr,
 165                                                   struct sk_buff *skb)
 166 {
 167         struct lowpan_peer *peer;
 168         struct in6_addr *nexthop;
 169         struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 170         int count = atomic_read(&dev->peer_count);
 171
 172         BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);
 173
 174         /* If we have multiple 6lowpan peers, then check where we should
 175          * send the packet. If only one peer exists, then we can send the
 176          * packet right away.
 177          */
 178         if (count == 1) {
 179                 rcu_read_lock();
 180                 peer = list_first_or_null_rcu(&dev->peers, struct lowpan_peer,
 181                                               list);
 182                 rcu_read_unlock();
 183                 return peer;
 184         }
 185
 186         if (!rt) {
 187                 nexthop = &lowpan_cb(skb)->gw;
 188
 189                 if (ipv6_addr_any(nexthop))
 190                         return NULL;
 191         } else {
 192                 nexthop = rt6_nexthop(rt, daddr);
 193
 194                 /* We need to remember the address because it is needed
 195                  * by bt_xmit() when sending the packet. In bt_xmit(), the
 196                  * destination routing info is not set.
 197                  */
 198                 memcpy(&lowpan_cb(skb)->gw, nexthop, sizeof(struct in6_addr));
 199         }
 200
 201         BT_DBG("gw %pI6c", nexthop);
 202
 203         rcu_read_lock();
 204
 205         list_for_each_entry_rcu(peer, &dev->peers, list) {
 206                 BT_DBG("dst addr %pMR dst type %d ip %pI6c",
 207                        &peer->chan->dst, peer->chan->dst_type,
 208                        &peer->peer_addr);
 209
 210                 if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
 211                         rcu_read_unlock();
 212                         return peer;
 213                 }
 214         }
 215
 216         rcu_read_unlock();
 217
 218         return NULL;
 219 }
 220
 221 static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
 222 {
 223         struct lowpan_dev *entry;
 224         struct lowpan_peer *peer = NULL;
 225
 226         rcu_read_lock();
 227
 228         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 229                 peer = __peer_lookup_conn(entry, conn);
 230                 if (peer)
 231                         break;
 232         }
 233
 234         rcu_read_unlock();
 235
 236         return peer;
 237 }
 238
 239 static struct lowpan_dev *lookup_dev(struct l2cap_conn *conn)
 240 {
 241         struct lowpan_dev *entry;
 242         struct lowpan_dev *dev = NULL;
 243
 244         rcu_read_lock();
 245
 246         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 247                 if (conn->hcon->hdev == entry->hdev) {
 248                         dev = entry;
 249                         break;
 250                 }
 251         }
 252
 253         rcu_read_unlock();
 254
 255         return dev;
 256 }
 257
 258 static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
 259 {
 260         struct sk_buff *skb_cp;
 261
 262         skb_cp = skb_copy(skb, GFP_ATOMIC);
 263         if (!skb_cp)
 264                 return NET_RX_DROP;
 265
 266         return netif_rx_ni(skb_cp);
 267 }
 268
 269 static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
 270                            struct l2cap_chan *chan)
 271 {
 272         const u8 *saddr, *daddr;
 273         struct lowpan_dev *dev;
 274         struct lowpan_peer *peer;
 275
 276         dev = lowpan_dev(netdev);
 277
 278         rcu_read_lock();
 279         peer = __peer_lookup_chan(dev, chan);
 280         rcu_read_unlock();
 281         if (!peer)
 282                 return -EINVAL;
 283
 284         saddr = peer->eui64_addr;
 285         daddr = dev->netdev->dev_addr;
 286
 287         return lowpan_header_decompress(skb, netdev, daddr, saddr);
 288 }
 289
 290 static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 291                     struct l2cap_chan *chan)
 292 {
 293         struct sk_buff *local_skb;
 294         int ret;
 295
 296         if (!netif_running(dev))
 297                 goto drop;
 298
 299         if (dev->type != ARPHRD_6LOWPAN || !skb->len)
 300                 goto drop;
 301
 302         skb_reset_network_header(skb);
 303
 304         skb = skb_share_check(skb, GFP_ATOMIC);
 305         if (!skb)
 306                 goto drop;
 307
 308         /* check that it's our buffer */
 309         if (lowpan_is_ipv6(*skb_network_header(skb))) {
 310                 /* Copy the packet so that the IPv6 header is
 311                  * properly aligned.
 312                  */
 313                 local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
 314                                             skb_tailroom(skb), GFP_ATOMIC);
 315                 if (!local_skb)
 316                         goto drop;
 317
 318                 local_skb->protocol = htons(ETH_P_IPV6);
 319                 local_skb->pkt_type = PACKET_HOST;
 320
 321                 skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
 322
 323                 if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
 324                         kfree_skb(local_skb);
 325                         goto drop;
 326                 }
 327
 328                 dev->stats.rx_bytes += skb->len;
 329                 dev->stats.rx_packets++;
 330
 331                 consume_skb(local_skb);
 332                 consume_skb(skb);
 333         } else if (lowpan_is_iphc(*skb_network_header(skb))) {
 334                 local_skb = skb_clone(skb, GFP_ATOMIC);
 335                 if (!local_skb)
 336                         goto drop;
 337
 338                 ret = iphc_decompress(local_skb, dev, chan);
 339                 if (ret < 0) {
 340                         kfree_skb(local_skb);
 341                         goto drop;
 342                 }
 343
 344                 local_skb->protocol = htons(ETH_P_IPV6);
 345                 local_skb->pkt_type = PACKET_HOST;
 346                 local_skb->dev = dev;
 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                 goto drop;
 361         }
 362
 363         return NET_RX_SUCCESS;
 364
 365 drop:
 366         dev->stats.rx_dropped++;
 367         return NET_RX_DROP;
 368 }
 369
 370 /* Packet from BT LE device */
 371 static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
 372 {
 373         struct lowpan_dev *dev;
 374         struct lowpan_peer *peer;
 375         int err;
 376
 377         peer = lookup_peer(chan->conn);
 378         if (!peer)
 379                 return -ENOENT;
 380
 381         dev = lookup_dev(chan->conn);
 382         if (!dev || !dev->netdev)
 383                 return -ENOENT;
 384
 385         err = recv_pkt(skb, dev->netdev, chan);
 386         if (err) {
 387                 BT_DBG("recv pkt %d", err);
 388                 err = -EAGAIN;
 389         }
 390
 391         return err;
 392 }
 393
 394 static u8 get_addr_type_from_eui64(u8 byte)
 395 {
 396         /* Is universal(0) or local(1) bit */
 397         return ((byte & 0x02) ? BDADDR_LE_RANDOM : BDADDR_LE_PUBLIC);
 398 }
 399
 400 static void copy_to_bdaddr(struct in6_addr *ip6_daddr, bdaddr_t *addr)
 401 {
 402         u8 *eui64 = ip6_daddr->s6_addr + 8;
 403
 404         addr->b[0] = eui64[7];
 405         addr->b[1] = eui64[6];
 406         addr->b[2] = eui64[5];
 407         addr->b[3] = eui64[2];
 408         addr->b[4] = eui64[1];
 409         addr->b[5] = eui64[0];
 410 }
 411
 412 static void convert_dest_bdaddr(struct in6_addr *ip6_daddr,
 413                                 bdaddr_t *addr, u8 *addr_type)
 414 {
 415         copy_to_bdaddr(ip6_daddr, addr);
 416
 417         /* We need to toggle the U/L bit that we got from IPv6 address
 418          * so that we get the proper address and type of the BD address.
 419          */
 420         addr->b[5] ^= 0x02;
 421
 422         *addr_type = get_addr_type_from_eui64(addr->b[5]);
 423 }
 424
 425 static int setup_header(struct sk_buff *skb, struct net_device *netdev,
 426                         bdaddr_t *peer_addr, u8 *peer_addr_type)
 427 {
 428         struct in6_addr ipv6_daddr;
 429         struct lowpan_dev *dev;
 430         struct lowpan_peer *peer;
 431         bdaddr_t addr, *any = BDADDR_ANY;
 432         u8 *daddr = any->b;
 433         int err, status = 0;
 434
 435         dev = lowpan_dev(netdev);
 436
 437         memcpy(&ipv6_daddr, &lowpan_cb(skb)->addr, sizeof(ipv6_daddr));
 438
 439         if (ipv6_addr_is_multicast(&ipv6_daddr)) {
 440                 lowpan_cb(skb)->chan = NULL;
 441         } else {
 442                 u8 addr_type;
 443
 444                 /* Get destination BT device from skb.
 445                  * If there is no such peer then discard the packet.
 446                  */
 447                 convert_dest_bdaddr(&ipv6_daddr, &addr, &addr_type);
 448
 449                 BT_DBG("dest addr %pMR type %d IP %pI6c", &addr,
 450                        addr_type, &ipv6_daddr);
 451
 452                 peer = peer_lookup_ba(dev, &addr, addr_type);
 453                 if (!peer) {
 454                         /* The packet might be sent to 6lowpan interface
 455                          * because of routing (either via default route
 456                          * or user set route) so get peer according to
 457                          * the destination address.
 458                          */
 459                         peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
 460                         if (!peer) {
 461                                 BT_DBG("no such peer %pMR found", &addr);
 462                                 return -ENOENT;
 463                         }
 464                 }
 465
 466                 daddr = peer->eui64_addr;
 467                 *peer_addr = addr;
 468                 *peer_addr_type = addr_type;
 469                 lowpan_cb(skb)->chan = peer->chan;
 470
 471                 status = 1;
 472         }
 473
 474         lowpan_header_compress(skb, netdev, daddr, dev->netdev->dev_addr);
 475
 476         err = dev_hard_header(skb, netdev, ETH_P_IPV6, NULL, NULL, 0);
 477         if (err < 0)
 478                 return err;
 479
 480         return status;
 481 }
 482
 483 static int header_create(struct sk_buff *skb, struct net_device *netdev,
 484                          unsigned short type, const void *_daddr,
 485                          const void *_saddr, unsigned int len)
 486 {
 487         struct ipv6hdr *hdr;
 488
 489         if (type != ETH_P_IPV6)
 490                 return -EINVAL;
 491
 492         hdr = ipv6_hdr(skb);
 493
 494         memcpy(&lowpan_cb(skb)->addr, &hdr->daddr, sizeof(struct in6_addr));
 495
 496         return 0;
 497 }
 498
 499 /* Packet to BT LE device */
 500 static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
 501                     struct net_device *netdev)
 502 {
 503         struct msghdr msg;
 504         struct kvec iv;
 505         int err;
 506
 507         /* Remember the skb so that we can send EAGAIN to the caller if
 508          * we run out of credits.
 509          */
 510         chan->data = skb;
 511
 512         iv.iov_base = skb->data;
 513         iv.iov_len = skb->len;
 514
 515         memset(&msg, 0, sizeof(msg));
 516         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, &iv, 1, skb->len);
 517
 518         err = l2cap_chan_send(chan, &msg, skb->len);
 519         if (err > 0) {
 520                 netdev->stats.tx_bytes += err;
 521                 netdev->stats.tx_packets++;
 522                 return 0;
 523         }
 524
 525         if (!err)
 526                 err = lowpan_cb(skb)->status;
 527
 528         if (err < 0) {
 529                 if (err == -EAGAIN)
 530                         netdev->stats.tx_dropped++;
 531                 else
 532                         netdev->stats.tx_errors++;
 533         }
 534
 535         return err;
 536 }
 537
 538 static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
 539 {
 540         struct sk_buff *local_skb;
 541         struct lowpan_dev *entry;
 542         int err = 0;
 543
 544         rcu_read_lock();
 545
 546         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 547                 struct lowpan_peer *pentry;
 548                 struct lowpan_dev *dev;
 549
 550                 if (entry->netdev != netdev)
 551                         continue;
 552
 553                 dev = lowpan_dev(entry->netdev);
 554
 555                 list_for_each_entry_rcu(pentry, &dev->peers, list) {
 556                         int ret;
 557
 558                         local_skb = skb_clone(skb, GFP_ATOMIC);
 559
 560                         BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
 561                                netdev->name,
 562                                &pentry->chan->dst, pentry->chan->dst_type,
 563                                &pentry->peer_addr, pentry->chan);
 564                         ret = send_pkt(pentry->chan, local_skb, netdev);
 565                         if (ret < 0)
 566                                 err = ret;
 567
 568                         kfree_skb(local_skb);
 569                 }
 570         }
 571
 572         rcu_read_unlock();
 573
 574         return err;
 575 }
 576
 577 static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
 578 {
 579         int err = 0;
 580         bdaddr_t addr;
 581         u8 addr_type;
 582
 583         /* We must take a copy of the skb before we modify/replace the ipv6
 584          * header as the header could be used elsewhere
 585          */
 586         skb = skb_unshare(skb, GFP_ATOMIC);
 587         if (!skb)
 588                 return NET_XMIT_DROP;
 589
 590         /* Return values from setup_header()
 591          *  <0 - error, packet is dropped
 592          *   0 - this is a multicast packet
 593          *   1 - this is unicast packet
 594          */
 595         err = setup_header(skb, netdev, &addr, &addr_type);
 596         if (err < 0) {
 597                 kfree_skb(skb);
 598                 return NET_XMIT_DROP;
 599         }
 600
 601         if (err) {
 602                 if (lowpan_cb(skb)->chan) {
 603                         BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
 604                                netdev->name, &addr, addr_type,
 605                                &lowpan_cb(skb)->addr, lowpan_cb(skb)->chan);
 606                         err = send_pkt(lowpan_cb(skb)->chan, skb, netdev);
 607                 } else {
 608                         err = -ENOENT;
 609                 }
 610         } else {
 611                 /* We need to send the packet to every device behind this
 612                  * interface.
 613                  */
 614                 err = send_mcast_pkt(skb, netdev);
 615         }
 616
 617         dev_kfree_skb(skb);
 618
 619         if (err)
 620                 BT_DBG("ERROR: xmit failed (%d)", err);
 621
 622         return err < 0 ? NET_XMIT_DROP : err;
 623 }
 624
 625 static struct lock_class_key bt_tx_busylock;
 626 static struct lock_class_key bt_netdev_xmit_lock_key;
 627
 628 static void bt_set_lockdep_class_one(struct net_device *dev,
 629                                      struct netdev_queue *txq,
 630                                      void *_unused)
 631 {
 632         lockdep_set_class(&txq->_xmit_lock, &bt_netdev_xmit_lock_key);
 633 }
 634
 635 static int bt_dev_init(struct net_device *dev)
 636 {
 637         netdev_for_each_tx_queue(dev, bt_set_lockdep_class_one, NULL);
 638         dev->qdisc_tx_busylock = &bt_tx_busylock;
 639
 640         return 0;
 641 }
 642
 643 static const struct net_device_ops netdev_ops = {
 644         .ndo_init               = bt_dev_init,
 645         .ndo_start_xmit         = bt_xmit,
 646 };
 647
 648 static struct header_ops header_ops = {
 649         .create = header_create,
 650 };
 651
 652 static void netdev_setup(struct net_device *dev)
 653 {
 654         dev->hard_header_len    = 0;
 655         dev->needed_tailroom    = 0;
 656         dev->flags              = IFF_RUNNING | IFF_POINTOPOINT |
 657                                   IFF_MULTICAST;
 658         dev->watchdog_timeo     = 0;
 659
 660         dev->netdev_ops         = &netdev_ops;
 661         dev->header_ops         = &header_ops;
 662         dev->destructor         = free_netdev;
 663 }
 664
 665 static struct device_type bt_type = {
 666         .name   = "bluetooth",
 667 };
 668
 669 static void set_addr(u8 *eui, u8 *addr, u8 addr_type)
 670 {
 671         /* addr is the BT address in little-endian format */
 672         eui[0] = addr[5];
 673         eui[1] = addr[4];
 674         eui[2] = addr[3];
 675         eui[3] = 0xFF;
 676         eui[4] = 0xFE;
 677         eui[5] = addr[2];
 678         eui[6] = addr[1];
 679         eui[7] = addr[0];
 680
 681         /* Universal/local bit set, BT 6lowpan draft ch. 3.2.1 */
 682         if (addr_type == BDADDR_LE_PUBLIC)
 683                 eui[0] &= ~0x02;
 684         else
 685                 eui[0] |= 0x02;
 686
 687         BT_DBG("type %d addr %*phC", addr_type, 8, eui);
 688 }
 689
 690 static void set_dev_addr(struct net_device *netdev, bdaddr_t *addr,
 691                          u8 addr_type)
 692 {
 693         netdev->addr_assign_type = NET_ADDR_PERM;
 694         set_addr(netdev->dev_addr, addr->b, addr_type);
 695 }
 696
 697 static void ifup(struct net_device *netdev)
 698 {
 699         int err;
 700
 701         rtnl_lock();
 702         err = dev_open(netdev);
 703         if (err < 0)
 704                 BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
 705         rtnl_unlock();
 706 }
 707
 708 static void ifdown(struct net_device *netdev)
 709 {
 710         int err;
 711
 712         rtnl_lock();
 713         err = dev_close(netdev);
 714         if (err < 0)
 715                 BT_INFO("iface %s cannot be closed (%d)", netdev->name, err);
 716         rtnl_unlock();
 717 }
 718
 719 static void do_notify_peers(struct work_struct *work)
 720 {
 721         struct lowpan_dev *dev = container_of(work, struct lowpan_dev,
 722                                               notify_peers.work);
 723
 724         netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
 725 }
 726
 727 static bool is_bt_6lowpan(struct hci_conn *hcon)
 728 {
 729         if (hcon->type != LE_LINK)
 730                 return false;
 731
 732         if (!enable_6lowpan)
 733                 return false;
 734
 735         return true;
 736 }
 737
 738 static struct l2cap_chan *chan_create(void)
 739 {
 740         struct l2cap_chan *chan;
 741
 742         chan = l2cap_chan_create();
 743         if (!chan)
 744                 return NULL;
 745
 746         l2cap_chan_set_defaults(chan);
 747
 748         chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
 749         chan->mode = L2CAP_MODE_LE_FLOWCTL;
 750         chan->imtu = 1280;
 751
 752         return chan;
 753 }
 754
 755 static void set_ip_addr_bits(u8 addr_type, u8 *addr)
 756 {
 757         if (addr_type == BDADDR_LE_PUBLIC)
 758                 *addr |= 0x02;
 759         else
 760                 *addr &= ~0x02;
 761 }
 762
 763 static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
 764                                         struct lowpan_dev *dev)
 765 {
 766         struct lowpan_peer *peer;
 767
 768         peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
 769         if (!peer)
 770                 return NULL;
 771
 772         peer->chan = chan;
 773         memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
 774
 775         /* RFC 2464 ch. 5 */
 776         peer->peer_addr.s6_addr[0] = 0xFE;
 777         peer->peer_addr.s6_addr[1] = 0x80;
 778         set_addr((u8 *)&peer->peer_addr.s6_addr + 8, chan->dst.b,
 779                  chan->dst_type);
 780
 781         memcpy(&peer->eui64_addr, (u8 *)&peer->peer_addr.s6_addr + 8,
 782                EUI64_ADDR_LEN);
 783
 784         /* IPv6 address needs to have the U/L bit set properly so toggle
 785          * it back here.
 786          */
 787         set_ip_addr_bits(chan->dst_type, (u8 *)&peer->peer_addr.s6_addr + 8);
 788
 789         spin_lock(&devices_lock);
 790         INIT_LIST_HEAD(&peer->list);
 791         peer_add(dev, peer);
 792         spin_unlock(&devices_lock);
 793
 794         /* Notifying peers about us needs to be done without locks held */
 795         INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
 796         schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
 797
 798         return peer->chan;
 799 }
 800
 801 static int setup_netdev(struct l2cap_chan *chan, struct lowpan_dev **dev)
 802 {
 803         struct net_device *netdev;
 804         int err = 0;
 805
 806         netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_dev)),
 807                               IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
 808                               netdev_setup);
 809         if (!netdev)
 810                 return -ENOMEM;
 811
 812         set_dev_addr(netdev, &chan->src, chan->src_type);
 813
 814         netdev->netdev_ops = &netdev_ops;
 815         SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
 816         SET_NETDEV_DEVTYPE(netdev, &bt_type);
 817
 818         *dev = lowpan_dev(netdev);
 819         (*dev)->netdev = netdev;
 820         (*dev)->hdev = chan->conn->hcon->hdev;
 821         INIT_LIST_HEAD(&(*dev)->peers);
 822
 823         spin_lock(&devices_lock);
 824         INIT_LIST_HEAD(&(*dev)->list);
 825         list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
 826         spin_unlock(&devices_lock);
 827
 828         lowpan_netdev_setup(netdev, LOWPAN_LLTYPE_BTLE);
 829
 830         err = register_netdev(netdev);
 831         if (err < 0) {
 832                 BT_INFO("register_netdev failed %d", err);
 833                 spin_lock(&devices_lock);
 834                 list_del_rcu(&(*dev)->list);
 835                 spin_unlock(&devices_lock);
 836                 free_netdev(netdev);
 837                 goto out;
 838         }
 839
 840         BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
 841                netdev->ifindex, &chan->dst, chan->dst_type,
 842                &chan->src, chan->src_type);
 843         set_bit(__LINK_STATE_PRESENT, &netdev->state);
 844
 845         return 0;
 846
 847 out:
 848         return err;
 849 }
 850
 851 static inline void chan_ready_cb(struct l2cap_chan *chan)
 852 {
 853         struct lowpan_dev *dev;
 854
 855         dev = lookup_dev(chan->conn);
 856
 857         BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
 858
 859         if (!dev) {
 860                 if (setup_netdev(chan, &dev) < 0) {
 861                         l2cap_chan_del(chan, -ENOENT);
 862                         return;
 863                 }
 864         }
 865
 866         if (!try_module_get(THIS_MODULE))
 867                 return;
 868
 869         add_peer_chan(chan, dev);
 870         ifup(dev->netdev);
 871 }
 872
 873 static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
 874 {
 875         struct l2cap_chan *chan;
 876
 877         chan = chan_create();
 878         if (!chan)
 879                 return NULL;
 880
 881         chan->ops = pchan->ops;
 882
 883         BT_DBG("chan %p pchan %p", chan, pchan);
 884
 885         return chan;
 886 }
 887
 888 static void delete_netdev(struct work_struct *work)
 889 {
 890         struct lowpan_dev *entry = container_of(work, struct lowpan_dev,
 891                                                 delete_netdev);
 892
 893         unregister_netdev(entry->netdev);
 894
 895         /* The entry pointer is deleted by the netdev destructor. */
 896 }
 897
 898 static void chan_close_cb(struct l2cap_chan *chan)
 899 {
 900         struct lowpan_dev *entry;
 901         struct lowpan_dev *dev = NULL;
 902         struct lowpan_peer *peer;
 903         int err = -ENOENT;
 904         bool last = false, remove = true;
 905
 906         BT_DBG("chan %p conn %p", chan, chan->conn);
 907
 908         if (chan->conn && chan->conn->hcon) {
 909                 if (!is_bt_6lowpan(chan->conn->hcon))
 910                         return;
 911
 912                 /* If conn is set, then the netdev is also there and we should
 913                  * not remove it.
 914                  */
 915                 remove = false;
 916         }
 917
 918         spin_lock(&devices_lock);
 919
 920         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 921                 dev = lowpan_dev(entry->netdev);
 922                 peer = __peer_lookup_chan(dev, chan);
 923                 if (peer) {
 924                         last = peer_del(dev, peer);
 925                         err = 0;
 926
 927                         BT_DBG("dev %p removing %speer %p", dev,
 928                                last ? "last " : "1 ", peer);
 929                         BT_DBG("chan %p orig refcnt %d", chan,
 930                                atomic_read(&chan->kref.refcount));
 931
 932                         l2cap_chan_put(chan);
 933                         break;
 934                 }
 935         }
 936
 937         if (!err && last && dev && !atomic_read(&dev->peer_count)) {
 938                 spin_unlock(&devices_lock);
 939
 940                 cancel_delayed_work_sync(&dev->notify_peers);
 941
 942                 ifdown(dev->netdev);
 943
 944                 if (remove) {
 945                         INIT_WORK(&entry->delete_netdev, delete_netdev);
 946                         schedule_work(&entry->delete_netdev);
 947                 }
 948         } else {
 949                 spin_unlock(&devices_lock);
 950         }
 951
 952         return;
 953 }
 954
 955 static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
 956 {
 957         BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
 958                state_to_string(state), err);
 959 }
 960
 961 static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
 962                                          unsigned long hdr_len,
 963                                          unsigned long len, int nb)
 964 {
 965         /* Note that we must allocate using GFP_ATOMIC here as
 966          * this function is called originally from netdev hard xmit
 967          * function in atomic context.
 968          */
 969         return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
 970 }
 971
 972 static void chan_suspend_cb(struct l2cap_chan *chan)
 973 {
 974         struct sk_buff *skb = chan->data;
 975
 976         BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);
 977
 978         if (!skb)
 979                 return;
 980
 981         lowpan_cb(skb)->status = -EAGAIN;
 982 }
 983
 984 static void chan_resume_cb(struct l2cap_chan *chan)
 985 {
 986         struct sk_buff *skb = chan->data;
 987
 988         BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);
 989
 990         if (!skb)
 991                 return;
 992
 993         lowpan_cb(skb)->status = 0;
 994 }
 995
 996 static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
 997 {
 998         return L2CAP_CONN_TIMEOUT;
 999 }
1000
1001 static const struct l2cap_ops bt_6lowpan_chan_ops = {
1002         .name                   = "L2CAP 6LoWPAN channel",
1003         .new_connection         = chan_new_conn_cb,
1004         .recv                   = chan_recv_cb,
1005         .close                  = chan_close_cb,
1006         .state_change           = chan_state_change_cb,
1007         .ready                  = chan_ready_cb,
1008         .resume                 = chan_resume_cb,
1009         .suspend                = chan_suspend_cb,
1010         .get_sndtimeo           = chan_get_sndtimeo_cb,
1011         .alloc_skb              = chan_alloc_skb_cb,
1012
1013         .teardown               = l2cap_chan_no_teardown,
1014         .defer                  = l2cap_chan_no_defer,
1015         .set_shutdown           = l2cap_chan_no_set_shutdown,
1016 };
1017
1018 static inline __u8 bdaddr_type(__u8 type)
1019 {
1020         if (type == ADDR_LE_DEV_PUBLIC)
1021                 return BDADDR_LE_PUBLIC;
1022         else
1023                 return BDADDR_LE_RANDOM;
1024 }
1025
1026 static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
1027 {
1028         struct l2cap_chan *chan;
1029         int err;
1030
1031         chan = chan_create();
1032         if (!chan)
1033                 return -EINVAL;
1034
1035         chan->ops = &bt_6lowpan_chan_ops;
1036
1037         err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
1038                                  addr, dst_type);
1039
1040         BT_DBG("chan %p err %d", chan, err);
1041         if (err < 0)
1042                 l2cap_chan_put(chan);
1043
1044         return err;
1045 }
1046
1047 static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
1048 {
1049         struct lowpan_peer *peer;
1050
1051         BT_DBG("conn %p dst type %d", conn, dst_type);
1052
1053         peer = lookup_peer(conn);
1054         if (!peer)
1055                 return -ENOENT;
1056
1057         BT_DBG("peer %p chan %p", peer, peer->chan);
1058
1059         l2cap_chan_close(peer->chan, ENOENT);
1060
1061         return 0;
1062 }
1063
1064 static struct l2cap_chan *bt_6lowpan_listen(void)
1065 {
1066         bdaddr_t *addr = BDADDR_ANY;
1067         struct l2cap_chan *chan;
1068         int err;
1069
1070         if (!enable_6lowpan)
1071                 return NULL;
1072
1073         chan = chan_create();
1074         if (!chan)
1075                 return NULL;
1076
1077         chan->ops = &bt_6lowpan_chan_ops;
1078         chan->state = BT_LISTEN;
1079         chan->src_type = BDADDR_LE_PUBLIC;
1080
1081         atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
1082
1083         BT_DBG("chan %p src type %d", chan, chan->src_type);
1084
1085         err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
1086         if (err) {
1087                 l2cap_chan_put(chan);
1088                 BT_ERR("psm cannot be added err %d", err);
1089                 return NULL;
1090         }
1091
1092         return chan;
1093 }
1094
1095 static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
1096                           struct l2cap_conn **conn)
1097 {
1098         struct hci_conn *hcon;
1099         struct hci_dev *hdev;
1100         bdaddr_t *src = BDADDR_ANY;
1101         int n;
1102
1103         n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
1104                    &addr->b[5], &addr->b[4], &addr->b[3],
1105                    &addr->b[2], &addr->b[1], &addr->b[0],
1106                    addr_type);
1107
1108         if (n < 7)
1109                 return -EINVAL;
1110
1111         hdev = hci_get_route(addr, src);
1112         if (!hdev)
1113                 return -ENOENT;
1114
1115         hci_dev_lock(hdev);
1116         hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
1117         hci_dev_unlock(hdev);
1118
1119         if (!hcon)
1120                 return -ENOENT;
1121
1122         *conn = (struct l2cap_conn *)hcon->l2cap_data;
1123
1124         BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);
1125
1126         return 0;
1127 }
1128
1129 static void disconnect_all_peers(void)
1130 {
1131         struct lowpan_dev *entry;
1132         struct lowpan_peer *peer, *tmp_peer, *new_peer;
1133         struct list_head peers;
1134
1135         INIT_LIST_HEAD(&peers);
1136
1137         /* We make a separate list of peers as the close_cb() will
1138          * modify the device peers list so it is better not to mess
1139          * with the same list at the same time.
1140          */
1141
1142         rcu_read_lock();
1143
1144         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1145                 list_for_each_entry_rcu(peer, &entry->peers, list) {
1146                         new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1147                         if (!new_peer)
1148                                 break;
1149
1150                         new_peer->chan = peer->chan;
1151                         INIT_LIST_HEAD(&new_peer->list);
1152
1153                         list_add(&new_peer->list, &peers);
1154                 }
1155         }
1156
1157         rcu_read_unlock();
1158
1159         spin_lock(&devices_lock);
1160         list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1161                 l2cap_chan_close(peer->chan, ENOENT);
1162
1163                 list_del_rcu(&peer->list);
1164                 kfree_rcu(peer, rcu);
1165         }
1166         spin_unlock(&devices_lock);
1167 }
1168
1169 struct set_enable {
1170         struct work_struct work;
1171         bool flag;
1172 };
1173
1174 static void do_enable_set(struct work_struct *work)
1175 {
1176         struct set_enable *set_enable = container_of(work,
1177                                                      struct set_enable, work);
1178
1179         if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1180                 /* Disconnect existing connections if 6lowpan is
1181                  * disabled
1182                  */
1183                 disconnect_all_peers();
1184
1185         enable_6lowpan = set_enable->flag;
1186
1187         if (listen_chan) {
1188                 l2cap_chan_close(listen_chan, 0);
1189                 l2cap_chan_put(listen_chan);
1190         }
1191
1192         listen_chan = bt_6lowpan_listen();
1193
1194         kfree(set_enable);
1195 }
1196
1197 static int lowpan_enable_set(void *data, u64 val)
1198 {
1199         struct set_enable *set_enable;
1200
1201         set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1202         if (!set_enable)
1203                 return -ENOMEM;
1204
1205         set_enable->flag = !!val;
1206         INIT_WORK(&set_enable->work, do_enable_set);
1207
1208         schedule_work(&set_enable->work);
1209
1210         return 0;
1211 }
1212
1213 static int lowpan_enable_get(void *data, u64 *val)
1214 {
1215         *val = enable_6lowpan;
1216         return 0;
1217 }
1218
1219 DEFINE_SIMPLE_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1220                         lowpan_enable_set, "%llu\n");
1221
1222 static ssize_t lowpan_control_write(struct file *fp,
1223                                     const char __user *user_buffer,
1224                                     size_t count,
1225                                     loff_t *position)
1226 {
1227         char buf[32];
1228         size_t buf_size = min(count, sizeof(buf) - 1);
1229         int ret;
1230         bdaddr_t addr;
1231         u8 addr_type;
1232         struct l2cap_conn *conn = NULL;
1233
1234         if (copy_from_user(buf, user_buffer, buf_size))
1235                 return -EFAULT;
1236
1237         buf[buf_size] = '\0';
1238
1239         if (memcmp(buf, "connect ", 8) == 0) {
1240                 ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1241                 if (ret == -EINVAL)
1242                         return ret;
1243
1244                 if (listen_chan) {
1245                         l2cap_chan_close(listen_chan, 0);
1246                         l2cap_chan_put(listen_chan);
1247                         listen_chan = NULL;
1248                 }
1249
1250                 if (conn) {
1251                         struct lowpan_peer *peer;
1252
1253                         if (!is_bt_6lowpan(conn->hcon))
1254                                 return -EINVAL;
1255
1256                         peer = lookup_peer(conn);
1257                         if (peer) {
1258                                 BT_DBG("6LoWPAN connection already exists");
1259                                 return -EALREADY;
1260                         }
1261
1262                         BT_DBG("conn %p dst %pMR type %d user %d", conn,
1263                                &conn->hcon->dst, conn->hcon->dst_type,
1264                                addr_type);
1265                 }
1266
1267                 ret = bt_6lowpan_connect(&addr, addr_type);
1268                 if (ret < 0)
1269                         return ret;
1270
1271                 return count;
1272         }
1273
1274         if (memcmp(buf, "disconnect ", 11) == 0) {
1275                 ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
1276                 if (ret < 0)
1277                         return ret;
1278
1279                 ret = bt_6lowpan_disconnect(conn, addr_type);
1280                 if (ret < 0)
1281                         return ret;
1282
1283                 return count;
1284         }
1285
1286         return count;
1287 }
1288
1289 static int lowpan_control_show(struct seq_file *f, void *ptr)
1290 {
1291         struct lowpan_dev *entry;
1292         struct lowpan_peer *peer;
1293
1294         spin_lock(&devices_lock);
1295
1296         list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1297                 list_for_each_entry(peer, &entry->peers, list)
1298                         seq_printf(f, "%pMR (type %u)\n",
1299                                    &peer->chan->dst, peer->chan->dst_type);
1300         }
1301
1302         spin_unlock(&devices_lock);
1303
1304         return 0;
1305 }
1306
1307 static int lowpan_control_open(struct inode *inode, struct file *file)
1308 {
1309         return single_open(file, lowpan_control_show, inode->i_private);
1310 }
1311
1312 static const struct file_operations lowpan_control_fops = {
1313         .open           = lowpan_control_open,
1314         .read           = seq_read,
1315         .write          = lowpan_control_write,
1316         .llseek         = seq_lseek,
1317         .release        = single_release,
1318 };
1319
1320 static void disconnect_devices(void)
1321 {
1322         struct lowpan_dev *entry, *tmp, *new_dev;
1323         struct list_head devices;
1324
1325         INIT_LIST_HEAD(&devices);
1326
1327         /* We make a separate list of devices because the unregister_netdev()
1328          * will call device_event() which will also want to modify the same
1329          * devices list.
1330          */
1331
1332         rcu_read_lock();
1333
1334         list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1335                 new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
1336                 if (!new_dev)
1337                         break;
1338
1339                 new_dev->netdev = entry->netdev;
1340                 INIT_LIST_HEAD(&new_dev->list);
1341
1342                 list_add_rcu(&new_dev->list, &devices);
1343         }
1344
1345         rcu_read_unlock();
1346
1347         list_for_each_entry_safe(entry, tmp, &devices, list) {
1348                 ifdown(entry->netdev);
1349                 BT_DBG("Unregistering netdev %s %p",
1350                        entry->netdev->name, entry->netdev);
1351                 unregister_netdev(entry->netdev);
1352                 kfree(entry);
1353         }
1354 }
1355
1356 static int device_event(struct notifier_block *unused,
1357                         unsigned long event, void *ptr)
1358 {
1359         struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
1360         struct lowpan_dev *entry;
1361
1362         if (netdev->type != ARPHRD_6LOWPAN)
1363                 return NOTIFY_DONE;
1364
1365         switch (event) {
1366         case NETDEV_UNREGISTER:
1367                 spin_lock(&devices_lock);
1368                 list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1369                         if (entry->netdev == netdev) {
1370                                 BT_DBG("Unregistered netdev %s %p",
1371                                        netdev->name, netdev);
1372                                 list_del(&entry->list);
1373                                 break;
1374                         }
1375                 }
1376                 spin_unlock(&devices_lock);
1377                 break;
1378         }
1379
1380         return NOTIFY_DONE;
1381 }
1382
1383 static struct notifier_block bt_6lowpan_dev_notifier = {
1384         .notifier_call = device_event,
1385 };
1386
1387 static int __init bt_6lowpan_init(void)
1388 {
1389         lowpan_enable_debugfs = debugfs_create_file("6lowpan_enable", 0644,
1390                                                     bt_debugfs, NULL,
1391                                                     &lowpan_enable_fops);
1392         lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1393                                                      bt_debugfs, NULL,
1394                                                      &lowpan_control_fops);
1395
1396         return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1397 }
1398
1399 static void __exit bt_6lowpan_exit(void)
1400 {
1401         debugfs_remove(lowpan_enable_debugfs);
1402         debugfs_remove(lowpan_control_debugfs);
1403
1404         if (listen_chan) {
1405                 l2cap_chan_close(listen_chan, 0);
1406                 l2cap_chan_put(listen_chan);
1407         }
1408
1409         disconnect_devices();
1410
1411         unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1412 }
1413
1414 module_init(bt_6lowpan_init);
1415 module_exit(bt_6lowpan_exit);
1416
1417 MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1418 MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1419 MODULE_VERSION(VERSION);
1420 MODULE_LICENSE("GPL");