linux/net/bluetooth/6lowpan.c
<<
>>
Prefs
   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
  32static struct dentry *lowpan_enable_debugfs;
  33static struct dentry *lowpan_control_debugfs;
  34
  35#define IFACE_NAME_TEMPLATE "bt%d"
  36
  37struct 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 */
  52static LIST_HEAD(bt_6lowpan_devices);
  53static DEFINE_SPINLOCK(devices_lock);
  54
  55static bool enable_6lowpan;
  56
  57/* We are listening incoming connections via this channel
  58 */
  59static struct l2cap_chan *listen_chan;
  60
  61struct 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
  71struct lowpan_btle_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
  83static inline struct lowpan_btle_dev *
  84lowpan_btle_dev(const struct net_device *netdev)
  85{
  86        return (struct lowpan_btle_dev *)lowpan_dev(netdev)->priv;
  87}
  88
  89static inline void peer_add(struct lowpan_btle_dev *dev,
  90                            struct lowpan_peer *peer)
  91{
  92        list_add_rcu(&peer->list, &dev->peers);
  93        atomic_inc(&dev->peer_count);
  94}
  95
  96static inline bool peer_del(struct lowpan_btle_dev *dev,
  97                            struct lowpan_peer *peer)
  98{
  99        list_del_rcu(&peer->list);
 100        kfree_rcu(peer, rcu);
 101
 102        module_put(THIS_MODULE);
 103
 104        if (atomic_dec_and_test(&dev->peer_count)) {
 105                BT_DBG("last peer");
 106                return true;
 107        }
 108
 109        return false;
 110}
 111
 112static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_btle_dev *dev,
 113                                                 bdaddr_t *ba, __u8 type)
 114{
 115        struct lowpan_peer *peer;
 116
 117        BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
 118               ba, type);
 119
 120        rcu_read_lock();
 121
 122        list_for_each_entry_rcu(peer, &dev->peers, list) {
 123                BT_DBG("dst addr %pMR dst type %d",
 124                       &peer->chan->dst, peer->chan->dst_type);
 125
 126                if (bacmp(&peer->chan->dst, ba))
 127                        continue;
 128
 129                if (type == peer->chan->dst_type) {
 130                        rcu_read_unlock();
 131                        return peer;
 132                }
 133        }
 134
 135        rcu_read_unlock();
 136
 137        return NULL;
 138}
 139
 140static inline struct lowpan_peer *
 141__peer_lookup_chan(struct lowpan_btle_dev *dev, struct l2cap_chan *chan)
 142{
 143        struct lowpan_peer *peer;
 144
 145        list_for_each_entry_rcu(peer, &dev->peers, list) {
 146                if (peer->chan == chan)
 147                        return peer;
 148        }
 149
 150        return NULL;
 151}
 152
 153static inline struct lowpan_peer *
 154__peer_lookup_conn(struct lowpan_btle_dev *dev, struct l2cap_conn *conn)
 155{
 156        struct lowpan_peer *peer;
 157
 158        list_for_each_entry_rcu(peer, &dev->peers, list) {
 159                if (peer->chan->conn == conn)
 160                        return peer;
 161        }
 162
 163        return NULL;
 164}
 165
 166static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_btle_dev *dev,
 167                                                  struct in6_addr *daddr,
 168                                                  struct sk_buff *skb)
 169{
 170        struct lowpan_peer *peer;
 171        struct in6_addr *nexthop;
 172        struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
 173        int count = atomic_read(&dev->peer_count);
 174
 175        BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);
 176
 177        /* If we have multiple 6lowpan peers, then check where we should
 178         * send the packet. If only one peer exists, then we can send the
 179         * packet right away.
 180         */
 181        if (count == 1) {
 182                rcu_read_lock();
 183                peer = list_first_or_null_rcu(&dev->peers, struct lowpan_peer,
 184                                              list);
 185                rcu_read_unlock();
 186                return peer;
 187        }
 188
 189        if (!rt) {
 190                nexthop = &lowpan_cb(skb)->gw;
 191
 192                if (ipv6_addr_any(nexthop))
 193                        return NULL;
 194        } else {
 195                nexthop = rt6_nexthop(rt, daddr);
 196
 197                /* We need to remember the address because it is needed
 198                 * by bt_xmit() when sending the packet. In bt_xmit(), the
 199                 * destination routing info is not set.
 200                 */
 201                memcpy(&lowpan_cb(skb)->gw, nexthop, sizeof(struct in6_addr));
 202        }
 203
 204        BT_DBG("gw %pI6c", nexthop);
 205
 206        rcu_read_lock();
 207
 208        list_for_each_entry_rcu(peer, &dev->peers, list) {
 209                BT_DBG("dst addr %pMR dst type %d ip %pI6c",
 210                       &peer->chan->dst, peer->chan->dst_type,
 211                       &peer->peer_addr);
 212
 213                if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
 214                        rcu_read_unlock();
 215                        return peer;
 216                }
 217        }
 218
 219        rcu_read_unlock();
 220
 221        return NULL;
 222}
 223
 224static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
 225{
 226        struct lowpan_btle_dev *entry;
 227        struct lowpan_peer *peer = NULL;
 228
 229        rcu_read_lock();
 230
 231        list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 232                peer = __peer_lookup_conn(entry, conn);
 233                if (peer)
 234                        break;
 235        }
 236
 237        rcu_read_unlock();
 238
 239        return peer;
 240}
 241
 242static struct lowpan_btle_dev *lookup_dev(struct l2cap_conn *conn)
 243{
 244        struct lowpan_btle_dev *entry;
 245        struct lowpan_btle_dev *dev = NULL;
 246
 247        rcu_read_lock();
 248
 249        list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 250                if (conn->hcon->hdev == entry->hdev) {
 251                        dev = entry;
 252                        break;
 253                }
 254        }
 255
 256        rcu_read_unlock();
 257
 258        return dev;
 259}
 260
 261static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
 262{
 263        struct sk_buff *skb_cp;
 264
 265        skb_cp = skb_copy(skb, GFP_ATOMIC);
 266        if (!skb_cp)
 267                return NET_RX_DROP;
 268
 269        return netif_rx_ni(skb_cp);
 270}
 271
 272static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
 273                           struct l2cap_chan *chan)
 274{
 275        const u8 *saddr, *daddr;
 276        struct lowpan_btle_dev *dev;
 277        struct lowpan_peer *peer;
 278
 279        dev = lowpan_btle_dev(netdev);
 280
 281        rcu_read_lock();
 282        peer = __peer_lookup_chan(dev, chan);
 283        rcu_read_unlock();
 284        if (!peer)
 285                return -EINVAL;
 286
 287        saddr = peer->eui64_addr;
 288        daddr = dev->netdev->dev_addr;
 289
 290        return lowpan_header_decompress(skb, netdev, daddr, saddr);
 291}
 292
 293static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 294                    struct l2cap_chan *chan)
 295{
 296        struct sk_buff *local_skb;
 297        int ret;
 298
 299        if (!netif_running(dev))
 300                goto drop;
 301
 302        if (dev->type != ARPHRD_6LOWPAN || !skb->len)
 303                goto drop;
 304
 305        skb_reset_network_header(skb);
 306
 307        skb = skb_share_check(skb, GFP_ATOMIC);
 308        if (!skb)
 309                goto drop;
 310
 311        /* check that it's our buffer */
 312        if (lowpan_is_ipv6(*skb_network_header(skb))) {
 313                /* Pull off the 1-byte of 6lowpan header. */
 314                skb_pull(skb, 1);
 315
 316                /* Copy the packet so that the IPv6 header is
 317                 * properly aligned.
 318                 */
 319                local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
 320                                            skb_tailroom(skb), GFP_ATOMIC);
 321                if (!local_skb)
 322                        goto drop;
 323
 324                local_skb->protocol = htons(ETH_P_IPV6);
 325                local_skb->pkt_type = PACKET_HOST;
 326                local_skb->dev = dev;
 327
 328                skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
 329
 330                if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
 331                        kfree_skb(local_skb);
 332                        goto drop;
 333                }
 334
 335                dev->stats.rx_bytes += skb->len;
 336                dev->stats.rx_packets++;
 337
 338                consume_skb(local_skb);
 339                consume_skb(skb);
 340        } else if (lowpan_is_iphc(*skb_network_header(skb))) {
 341                local_skb = skb_clone(skb, GFP_ATOMIC);
 342                if (!local_skb)
 343                        goto drop;
 344
 345                local_skb->dev = dev;
 346
 347                ret = iphc_decompress(local_skb, dev, chan);
 348                if (ret < 0) {
 349                        kfree_skb(local_skb);
 350                        goto drop;
 351                }
 352
 353                local_skb->protocol = htons(ETH_P_IPV6);
 354                local_skb->pkt_type = PACKET_HOST;
 355
 356                if (give_skb_to_upper(local_skb, dev)
 357                                != NET_RX_SUCCESS) {
 358                        kfree_skb(local_skb);
 359                        goto drop;
 360                }
 361
 362                dev->stats.rx_bytes += skb->len;
 363                dev->stats.rx_packets++;
 364
 365                consume_skb(local_skb);
 366                consume_skb(skb);
 367        } else {
 368                goto drop;
 369        }
 370
 371        return NET_RX_SUCCESS;
 372
 373drop:
 374        dev->stats.rx_dropped++;
 375        return NET_RX_DROP;
 376}
 377
 378/* Packet from BT LE device */
 379static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
 380{
 381        struct lowpan_btle_dev *dev;
 382        struct lowpan_peer *peer;
 383        int err;
 384
 385        peer = lookup_peer(chan->conn);
 386        if (!peer)
 387                return -ENOENT;
 388
 389        dev = lookup_dev(chan->conn);
 390        if (!dev || !dev->netdev)
 391                return -ENOENT;
 392
 393        err = recv_pkt(skb, dev->netdev, chan);
 394        if (err) {
 395                BT_DBG("recv pkt %d", err);
 396                err = -EAGAIN;
 397        }
 398
 399        return err;
 400}
 401
 402static u8 get_addr_type_from_eui64(u8 byte)
 403{
 404        /* Is universal(0) or local(1) bit */
 405        return ((byte & 0x02) ? BDADDR_LE_RANDOM : BDADDR_LE_PUBLIC);
 406}
 407
 408static void copy_to_bdaddr(struct in6_addr *ip6_daddr, bdaddr_t *addr)
 409{
 410        u8 *eui64 = ip6_daddr->s6_addr + 8;
 411
 412        addr->b[0] = eui64[7];
 413        addr->b[1] = eui64[6];
 414        addr->b[2] = eui64[5];
 415        addr->b[3] = eui64[2];
 416        addr->b[4] = eui64[1];
 417        addr->b[5] = eui64[0];
 418}
 419
 420static void convert_dest_bdaddr(struct in6_addr *ip6_daddr,
 421                                bdaddr_t *addr, u8 *addr_type)
 422{
 423        copy_to_bdaddr(ip6_daddr, addr);
 424
 425        /* We need to toggle the U/L bit that we got from IPv6 address
 426         * so that we get the proper address and type of the BD address.
 427         */
 428        addr->b[5] ^= 0x02;
 429
 430        *addr_type = get_addr_type_from_eui64(addr->b[5]);
 431}
 432
 433static int setup_header(struct sk_buff *skb, struct net_device *netdev,
 434                        bdaddr_t *peer_addr, u8 *peer_addr_type)
 435{
 436        struct in6_addr ipv6_daddr;
 437        struct ipv6hdr *hdr;
 438        struct lowpan_btle_dev *dev;
 439        struct lowpan_peer *peer;
 440        bdaddr_t addr, *any = BDADDR_ANY;
 441        u8 *daddr = any->b;
 442        int err, status = 0;
 443
 444        hdr = ipv6_hdr(skb);
 445
 446        dev = lowpan_btle_dev(netdev);
 447
 448        memcpy(&ipv6_daddr, &hdr->daddr, sizeof(ipv6_daddr));
 449
 450        if (ipv6_addr_is_multicast(&ipv6_daddr)) {
 451                lowpan_cb(skb)->chan = NULL;
 452        } else {
 453                u8 addr_type;
 454
 455                /* Get destination BT device from skb.
 456                 * If there is no such peer then discard the packet.
 457                 */
 458                convert_dest_bdaddr(&ipv6_daddr, &addr, &addr_type);
 459
 460                BT_DBG("dest addr %pMR type %d IP %pI6c", &addr,
 461                       addr_type, &ipv6_daddr);
 462
 463                peer = peer_lookup_ba(dev, &addr, addr_type);
 464                if (!peer) {
 465                        /* The packet might be sent to 6lowpan interface
 466                         * because of routing (either via default route
 467                         * or user set route) so get peer according to
 468                         * the destination address.
 469                         */
 470                        peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
 471                        if (!peer) {
 472                                BT_DBG("no such peer %pMR found", &addr);
 473                                return -ENOENT;
 474                        }
 475                }
 476
 477                daddr = peer->eui64_addr;
 478                *peer_addr = addr;
 479                *peer_addr_type = addr_type;
 480                lowpan_cb(skb)->chan = peer->chan;
 481
 482                status = 1;
 483        }
 484
 485        lowpan_header_compress(skb, netdev, daddr, dev->netdev->dev_addr);
 486
 487        err = dev_hard_header(skb, netdev, ETH_P_IPV6, NULL, NULL, 0);
 488        if (err < 0)
 489                return err;
 490
 491        return status;
 492}
 493
 494static int header_create(struct sk_buff *skb, struct net_device *netdev,
 495                         unsigned short type, const void *_daddr,
 496                         const void *_saddr, unsigned int len)
 497{
 498        if (type != ETH_P_IPV6)
 499                return -EINVAL;
 500
 501        return 0;
 502}
 503
 504/* Packet to BT LE device */
 505static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
 506                    struct net_device *netdev)
 507{
 508        struct msghdr msg;
 509        struct kvec iv;
 510        int err;
 511
 512        /* Remember the skb so that we can send EAGAIN to the caller if
 513         * we run out of credits.
 514         */
 515        chan->data = skb;
 516
 517        iv.iov_base = skb->data;
 518        iv.iov_len = skb->len;
 519
 520        memset(&msg, 0, sizeof(msg));
 521        iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, &iv, 1, skb->len);
 522
 523        err = l2cap_chan_send(chan, &msg, skb->len);
 524        if (err > 0) {
 525                netdev->stats.tx_bytes += err;
 526                netdev->stats.tx_packets++;
 527                return 0;
 528        }
 529
 530        if (!err)
 531                err = lowpan_cb(skb)->status;
 532
 533        if (err < 0) {
 534                if (err == -EAGAIN)
 535                        netdev->stats.tx_dropped++;
 536                else
 537                        netdev->stats.tx_errors++;
 538        }
 539
 540        return err;
 541}
 542
 543static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
 544{
 545        struct sk_buff *local_skb;
 546        struct lowpan_btle_dev *entry;
 547        int err = 0;
 548
 549        rcu_read_lock();
 550
 551        list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 552                struct lowpan_peer *pentry;
 553                struct lowpan_btle_dev *dev;
 554
 555                if (entry->netdev != netdev)
 556                        continue;
 557
 558                dev = lowpan_btle_dev(entry->netdev);
 559
 560                list_for_each_entry_rcu(pentry, &dev->peers, list) {
 561                        int ret;
 562
 563                        local_skb = skb_clone(skb, GFP_ATOMIC);
 564
 565                        BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
 566                               netdev->name,
 567                               &pentry->chan->dst, pentry->chan->dst_type,
 568                               &pentry->peer_addr, pentry->chan);
 569                        ret = send_pkt(pentry->chan, local_skb, netdev);
 570                        if (ret < 0)
 571                                err = ret;
 572
 573                        kfree_skb(local_skb);
 574                }
 575        }
 576
 577        rcu_read_unlock();
 578
 579        return err;
 580}
 581
 582static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
 583{
 584        int err = 0;
 585        bdaddr_t addr;
 586        u8 addr_type;
 587
 588        /* We must take a copy of the skb before we modify/replace the ipv6
 589         * header as the header could be used elsewhere
 590         */
 591        skb = skb_unshare(skb, GFP_ATOMIC);
 592        if (!skb)
 593                return NET_XMIT_DROP;
 594
 595        /* Return values from setup_header()
 596         *  <0 - error, packet is dropped
 597         *   0 - this is a multicast packet
 598         *   1 - this is unicast packet
 599         */
 600        err = setup_header(skb, netdev, &addr, &addr_type);
 601        if (err < 0) {
 602                kfree_skb(skb);
 603                return NET_XMIT_DROP;
 604        }
 605
 606        if (err) {
 607                if (lowpan_cb(skb)->chan) {
 608                        BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
 609                               netdev->name, &addr, addr_type,
 610                               &lowpan_cb(skb)->addr, lowpan_cb(skb)->chan);
 611                        err = send_pkt(lowpan_cb(skb)->chan, skb, netdev);
 612                } else {
 613                        err = -ENOENT;
 614                }
 615        } else {
 616                /* We need to send the packet to every device behind this
 617                 * interface.
 618                 */
 619                err = send_mcast_pkt(skb, netdev);
 620        }
 621
 622        dev_kfree_skb(skb);
 623
 624        if (err)
 625                BT_DBG("ERROR: xmit failed (%d)", err);
 626
 627        return err < 0 ? NET_XMIT_DROP : err;
 628}
 629
 630static int bt_dev_init(struct net_device *dev)
 631{
 632        netdev_lockdep_set_classes(dev);
 633
 634        return 0;
 635}
 636
 637static const struct net_device_ops netdev_ops = {
 638        .ndo_init               = bt_dev_init,
 639        .ndo_start_xmit         = bt_xmit,
 640};
 641
 642static struct header_ops header_ops = {
 643        .create = header_create,
 644};
 645
 646static void netdev_setup(struct net_device *dev)
 647{
 648        dev->hard_header_len    = 0;
 649        dev->needed_tailroom    = 0;
 650        dev->flags              = IFF_RUNNING | IFF_POINTOPOINT |
 651                                  IFF_MULTICAST;
 652        dev->watchdog_timeo     = 0;
 653
 654        dev->netdev_ops         = &netdev_ops;
 655        dev->header_ops         = &header_ops;
 656        dev->destructor         = free_netdev;
 657}
 658
 659static struct device_type bt_type = {
 660        .name   = "bluetooth",
 661};
 662
 663static void set_addr(u8 *eui, u8 *addr, u8 addr_type)
 664{
 665        /* addr is the BT address in little-endian format */
 666        eui[0] = addr[5];
 667        eui[1] = addr[4];
 668        eui[2] = addr[3];
 669        eui[3] = 0xFF;
 670        eui[4] = 0xFE;
 671        eui[5] = addr[2];
 672        eui[6] = addr[1];
 673        eui[7] = addr[0];
 674
 675        /* Universal/local bit set, BT 6lowpan draft ch. 3.2.1 */
 676        if (addr_type == BDADDR_LE_PUBLIC)
 677                eui[0] &= ~0x02;
 678        else
 679                eui[0] |= 0x02;
 680
 681        BT_DBG("type %d addr %*phC", addr_type, 8, eui);
 682}
 683
 684static void set_dev_addr(struct net_device *netdev, bdaddr_t *addr,
 685                         u8 addr_type)
 686{
 687        netdev->addr_assign_type = NET_ADDR_PERM;
 688        set_addr(netdev->dev_addr, addr->b, addr_type);
 689}
 690
 691static void ifup(struct net_device *netdev)
 692{
 693        int err;
 694
 695        rtnl_lock();
 696        err = dev_open(netdev);
 697        if (err < 0)
 698                BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
 699        rtnl_unlock();
 700}
 701
 702static void ifdown(struct net_device *netdev)
 703{
 704        int err;
 705
 706        rtnl_lock();
 707        err = dev_close(netdev);
 708        if (err < 0)
 709                BT_INFO("iface %s cannot be closed (%d)", netdev->name, err);
 710        rtnl_unlock();
 711}
 712
 713static void do_notify_peers(struct work_struct *work)
 714{
 715        struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_dev,
 716                                                   notify_peers.work);
 717
 718        netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
 719}
 720
 721static bool is_bt_6lowpan(struct hci_conn *hcon)
 722{
 723        if (hcon->type != LE_LINK)
 724                return false;
 725
 726        if (!enable_6lowpan)
 727                return false;
 728
 729        return true;
 730}
 731
 732static struct l2cap_chan *chan_create(void)
 733{
 734        struct l2cap_chan *chan;
 735
 736        chan = l2cap_chan_create();
 737        if (!chan)
 738                return NULL;
 739
 740        l2cap_chan_set_defaults(chan);
 741
 742        chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
 743        chan->mode = L2CAP_MODE_LE_FLOWCTL;
 744        chan->imtu = 1280;
 745
 746        return chan;
 747}
 748
 749static void set_ip_addr_bits(u8 addr_type, u8 *addr)
 750{
 751        if (addr_type == BDADDR_LE_PUBLIC)
 752                *addr |= 0x02;
 753        else
 754                *addr &= ~0x02;
 755}
 756
 757static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
 758                                        struct lowpan_btle_dev *dev)
 759{
 760        struct lowpan_peer *peer;
 761
 762        peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
 763        if (!peer)
 764                return NULL;
 765
 766        peer->chan = chan;
 767        memset(&peer->peer_addr, 0, sizeof(struct in6_addr));
 768
 769        /* RFC 2464 ch. 5 */
 770        peer->peer_addr.s6_addr[0] = 0xFE;
 771        peer->peer_addr.s6_addr[1] = 0x80;
 772        set_addr((u8 *)&peer->peer_addr.s6_addr + 8, chan->dst.b,
 773                 chan->dst_type);
 774
 775        memcpy(&peer->eui64_addr, (u8 *)&peer->peer_addr.s6_addr + 8,
 776               EUI64_ADDR_LEN);
 777
 778        /* IPv6 address needs to have the U/L bit set properly so toggle
 779         * it back here.
 780         */
 781        set_ip_addr_bits(chan->dst_type, (u8 *)&peer->peer_addr.s6_addr + 8);
 782
 783        spin_lock(&devices_lock);
 784        INIT_LIST_HEAD(&peer->list);
 785        peer_add(dev, peer);
 786        spin_unlock(&devices_lock);
 787
 788        /* Notifying peers about us needs to be done without locks held */
 789        INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
 790        schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
 791
 792        return peer->chan;
 793}
 794
 795static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
 796{
 797        struct net_device *netdev;
 798        int err = 0;
 799
 800        netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
 801                              IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
 802                              netdev_setup);
 803        if (!netdev)
 804                return -ENOMEM;
 805
 806        set_dev_addr(netdev, &chan->src, chan->src_type);
 807
 808        netdev->netdev_ops = &netdev_ops;
 809        SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
 810        SET_NETDEV_DEVTYPE(netdev, &bt_type);
 811
 812        *dev = lowpan_btle_dev(netdev);
 813        (*dev)->netdev = netdev;
 814        (*dev)->hdev = chan->conn->hcon->hdev;
 815        INIT_LIST_HEAD(&(*dev)->peers);
 816
 817        spin_lock(&devices_lock);
 818        INIT_LIST_HEAD(&(*dev)->list);
 819        list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
 820        spin_unlock(&devices_lock);
 821
 822        err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
 823        if (err < 0) {
 824                BT_INFO("register_netdev failed %d", err);
 825                spin_lock(&devices_lock);
 826                list_del_rcu(&(*dev)->list);
 827                spin_unlock(&devices_lock);
 828                free_netdev(netdev);
 829                goto out;
 830        }
 831
 832        BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
 833               netdev->ifindex, &chan->dst, chan->dst_type,
 834               &chan->src, chan->src_type);
 835        set_bit(__LINK_STATE_PRESENT, &netdev->state);
 836
 837        return 0;
 838
 839out:
 840        return err;
 841}
 842
 843static inline void chan_ready_cb(struct l2cap_chan *chan)
 844{
 845        struct lowpan_btle_dev *dev;
 846
 847        dev = lookup_dev(chan->conn);
 848
 849        BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);
 850
 851        if (!dev) {
 852                if (setup_netdev(chan, &dev) < 0) {
 853                        l2cap_chan_del(chan, -ENOENT);
 854                        return;
 855                }
 856        }
 857
 858        if (!try_module_get(THIS_MODULE))
 859                return;
 860
 861        add_peer_chan(chan, dev);
 862        ifup(dev->netdev);
 863}
 864
 865static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
 866{
 867        struct l2cap_chan *chan;
 868
 869        chan = chan_create();
 870        if (!chan)
 871                return NULL;
 872
 873        chan->ops = pchan->ops;
 874
 875        BT_DBG("chan %p pchan %p", chan, pchan);
 876
 877        return chan;
 878}
 879
 880static void delete_netdev(struct work_struct *work)
 881{
 882        struct lowpan_btle_dev *entry = container_of(work,
 883                                                     struct lowpan_btle_dev,
 884                                                     delete_netdev);
 885
 886        lowpan_unregister_netdev(entry->netdev);
 887
 888        /* The entry pointer is deleted by the netdev destructor. */
 889}
 890
 891static void chan_close_cb(struct l2cap_chan *chan)
 892{
 893        struct lowpan_btle_dev *entry;
 894        struct lowpan_btle_dev *dev = NULL;
 895        struct lowpan_peer *peer;
 896        int err = -ENOENT;
 897        bool last = false, remove = true;
 898
 899        BT_DBG("chan %p conn %p", chan, chan->conn);
 900
 901        if (chan->conn && chan->conn->hcon) {
 902                if (!is_bt_6lowpan(chan->conn->hcon))
 903                        return;
 904
 905                /* If conn is set, then the netdev is also there and we should
 906                 * not remove it.
 907                 */
 908                remove = false;
 909        }
 910
 911        spin_lock(&devices_lock);
 912
 913        list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
 914                dev = lowpan_btle_dev(entry->netdev);
 915                peer = __peer_lookup_chan(dev, chan);
 916                if (peer) {
 917                        last = peer_del(dev, peer);
 918                        err = 0;
 919
 920                        BT_DBG("dev %p removing %speer %p", dev,
 921                               last ? "last " : "1 ", peer);
 922                        BT_DBG("chan %p orig refcnt %d", chan,
 923                               kref_read(&chan->kref));
 924
 925                        l2cap_chan_put(chan);
 926                        break;
 927                }
 928        }
 929
 930        if (!err && last && dev && !atomic_read(&dev->peer_count)) {
 931                spin_unlock(&devices_lock);
 932
 933                cancel_delayed_work_sync(&dev->notify_peers);
 934
 935                ifdown(dev->netdev);
 936
 937                if (remove) {
 938                        INIT_WORK(&entry->delete_netdev, delete_netdev);
 939                        schedule_work(&entry->delete_netdev);
 940                }
 941        } else {
 942                spin_unlock(&devices_lock);
 943        }
 944
 945        return;
 946}
 947
 948static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
 949{
 950        BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
 951               state_to_string(state), err);
 952}
 953
 954static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
 955                                         unsigned long hdr_len,
 956                                         unsigned long len, int nb)
 957{
 958        /* Note that we must allocate using GFP_ATOMIC here as
 959         * this function is called originally from netdev hard xmit
 960         * function in atomic context.
 961         */
 962        return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
 963}
 964
 965static void chan_suspend_cb(struct l2cap_chan *chan)
 966{
 967        struct sk_buff *skb = chan->data;
 968
 969        BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);
 970
 971        if (!skb)
 972                return;
 973
 974        lowpan_cb(skb)->status = -EAGAIN;
 975}
 976
 977static void chan_resume_cb(struct l2cap_chan *chan)
 978{
 979        struct sk_buff *skb = chan->data;
 980
 981        BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);
 982
 983        if (!skb)
 984                return;
 985
 986        lowpan_cb(skb)->status = 0;
 987}
 988
 989static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
 990{
 991        return L2CAP_CONN_TIMEOUT;
 992}
 993
 994static const struct l2cap_ops bt_6lowpan_chan_ops = {
 995        .name                   = "L2CAP 6LoWPAN channel",
 996        .new_connection         = chan_new_conn_cb,
 997        .recv                   = chan_recv_cb,
 998        .close                  = chan_close_cb,
 999        .state_change           = chan_state_change_cb,
1000        .ready                  = chan_ready_cb,
1001        .resume                 = chan_resume_cb,
1002        .suspend                = chan_suspend_cb,
1003        .get_sndtimeo           = chan_get_sndtimeo_cb,
1004        .alloc_skb              = chan_alloc_skb_cb,
1005
1006        .teardown               = l2cap_chan_no_teardown,
1007        .defer                  = l2cap_chan_no_defer,
1008        .set_shutdown           = l2cap_chan_no_set_shutdown,
1009};
1010
1011static inline __u8 bdaddr_type(__u8 type)
1012{
1013        if (type == ADDR_LE_DEV_PUBLIC)
1014                return BDADDR_LE_PUBLIC;
1015        else
1016                return BDADDR_LE_RANDOM;
1017}
1018
1019static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
1020{
1021        struct l2cap_chan *chan;
1022        int err;
1023
1024        chan = chan_create();
1025        if (!chan)
1026                return -EINVAL;
1027
1028        chan->ops = &bt_6lowpan_chan_ops;
1029
1030        err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
1031                                 addr, dst_type);
1032
1033        BT_DBG("chan %p err %d", chan, err);
1034        if (err < 0)
1035                l2cap_chan_put(chan);
1036
1037        return err;
1038}
1039
1040static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
1041{
1042        struct lowpan_peer *peer;
1043
1044        BT_DBG("conn %p dst type %d", conn, dst_type);
1045
1046        peer = lookup_peer(conn);
1047        if (!peer)
1048                return -ENOENT;
1049
1050        BT_DBG("peer %p chan %p", peer, peer->chan);
1051
1052        l2cap_chan_close(peer->chan, ENOENT);
1053
1054        return 0;
1055}
1056
1057static struct l2cap_chan *bt_6lowpan_listen(void)
1058{
1059        bdaddr_t *addr = BDADDR_ANY;
1060        struct l2cap_chan *chan;
1061        int err;
1062
1063        if (!enable_6lowpan)
1064                return NULL;
1065
1066        chan = chan_create();
1067        if (!chan)
1068                return NULL;
1069
1070        chan->ops = &bt_6lowpan_chan_ops;
1071        chan->state = BT_LISTEN;
1072        chan->src_type = BDADDR_LE_PUBLIC;
1073
1074        atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
1075
1076        BT_DBG("chan %p src type %d", chan, chan->src_type);
1077
1078        err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
1079        if (err) {
1080                l2cap_chan_put(chan);
1081                BT_ERR("psm cannot be added err %d", err);
1082                return NULL;
1083        }
1084
1085        return chan;
1086}
1087
1088static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
1089                          struct l2cap_conn **conn)
1090{
1091        struct hci_conn *hcon;
1092        struct hci_dev *hdev;
1093        int n;
1094
1095        n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
1096                   &addr->b[5], &addr->b[4], &addr->b[3],
1097                   &addr->b[2], &addr->b[1], &addr->b[0],
1098                   addr_type);
1099
1100        if (n < 7)
1101                return -EINVAL;
1102
1103        /* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
1104        hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
1105        if (!hdev)
1106                return -ENOENT;
1107
1108        hci_dev_lock(hdev);
1109        hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
1110        hci_dev_unlock(hdev);
1111
1112        if (!hcon)
1113                return -ENOENT;
1114
1115        *conn = (struct l2cap_conn *)hcon->l2cap_data;
1116
1117        BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);
1118
1119        return 0;
1120}
1121
1122static void disconnect_all_peers(void)
1123{
1124        struct lowpan_btle_dev *entry;
1125        struct lowpan_peer *peer, *tmp_peer, *new_peer;
1126        struct list_head peers;
1127
1128        INIT_LIST_HEAD(&peers);
1129
1130        /* We make a separate list of peers as the close_cb() will
1131         * modify the device peers list so it is better not to mess
1132         * with the same list at the same time.
1133         */
1134
1135        rcu_read_lock();
1136
1137        list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1138                list_for_each_entry_rcu(peer, &entry->peers, list) {
1139                        new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
1140                        if (!new_peer)
1141                                break;
1142
1143                        new_peer->chan = peer->chan;
1144                        INIT_LIST_HEAD(&new_peer->list);
1145
1146                        list_add(&new_peer->list, &peers);
1147                }
1148        }
1149
1150        rcu_read_unlock();
1151
1152        spin_lock(&devices_lock);
1153        list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
1154                l2cap_chan_close(peer->chan, ENOENT);
1155
1156                list_del_rcu(&peer->list);
1157                kfree_rcu(peer, rcu);
1158        }
1159        spin_unlock(&devices_lock);
1160}
1161
1162struct set_enable {
1163        struct work_struct work;
1164        bool flag;
1165};
1166
1167static void do_enable_set(struct work_struct *work)
1168{
1169        struct set_enable *set_enable = container_of(work,
1170                                                     struct set_enable, work);
1171
1172        if (!set_enable->flag || enable_6lowpan != set_enable->flag)
1173                /* Disconnect existing connections if 6lowpan is
1174                 * disabled
1175                 */
1176                disconnect_all_peers();
1177
1178        enable_6lowpan = set_enable->flag;
1179
1180        if (listen_chan) {
1181                l2cap_chan_close(listen_chan, 0);
1182                l2cap_chan_put(listen_chan);
1183        }
1184
1185        listen_chan = bt_6lowpan_listen();
1186
1187        kfree(set_enable);
1188}
1189
1190static int lowpan_enable_set(void *data, u64 val)
1191{
1192        struct set_enable *set_enable;
1193
1194        set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
1195        if (!set_enable)
1196                return -ENOMEM;
1197
1198        set_enable->flag = !!val;
1199        INIT_WORK(&set_enable->work, do_enable_set);
1200
1201        schedule_work(&set_enable->work);
1202
1203        return 0;
1204}
1205
1206static int lowpan_enable_get(void *data, u64 *val)
1207{
1208        *val = enable_6lowpan;
1209        return 0;
1210}
1211
1212DEFINE_SIMPLE_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
1213                        lowpan_enable_set, "%llu\n");
1214
1215static ssize_t lowpan_control_write(struct file *fp,
1216                                    const char __user *user_buffer,
1217                                    size_t count,
1218                                    loff_t *position)
1219{
1220        char buf[32];
1221        size_t buf_size = min(count, sizeof(buf) - 1);
1222        int ret;
1223        bdaddr_t addr;
1224        u8 addr_type;
1225        struct l2cap_conn *conn = NULL;
1226
1227        if (copy_from_user(buf, user_buffer, buf_size))
1228                return -EFAULT;
1229
1230        buf[buf_size] = '\0';
1231
1232        if (memcmp(buf, "connect ", 8) == 0) {
1233                ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
1234                if (ret == -EINVAL)
1235                        return ret;
1236
1237                if (listen_chan) {
1238                        l2cap_chan_close(listen_chan, 0);
1239                        l2cap_chan_put(listen_chan);
1240                        listen_chan = NULL;
1241                }
1242
1243                if (conn) {
1244                        struct lowpan_peer *peer;
1245
1246                        if (!is_bt_6lowpan(conn->hcon))
1247                                return -EINVAL;
1248
1249                        peer = lookup_peer(conn);
1250                        if (peer) {
1251                                BT_DBG("6LoWPAN connection already exists");
1252                                return -EALREADY;
1253                        }
1254
1255                        BT_DBG("conn %p dst %pMR type %d user %d", conn,
1256                               &conn->hcon->dst, conn->hcon->dst_type,
1257                               addr_type);
1258                }
1259
1260                ret = bt_6lowpan_connect(&addr, addr_type);
1261                if (ret < 0)
1262                        return ret;
1263
1264                return count;
1265        }
1266
1267        if (memcmp(buf, "disconnect ", 11) == 0) {
1268                ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
1269                if (ret < 0)
1270                        return ret;
1271
1272                ret = bt_6lowpan_disconnect(conn, addr_type);
1273                if (ret < 0)
1274                        return ret;
1275
1276                return count;
1277        }
1278
1279        return count;
1280}
1281
1282static int lowpan_control_show(struct seq_file *f, void *ptr)
1283{
1284        struct lowpan_btle_dev *entry;
1285        struct lowpan_peer *peer;
1286
1287        spin_lock(&devices_lock);
1288
1289        list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1290                list_for_each_entry(peer, &entry->peers, list)
1291                        seq_printf(f, "%pMR (type %u)\n",
1292                                   &peer->chan->dst, peer->chan->dst_type);
1293        }
1294
1295        spin_unlock(&devices_lock);
1296
1297        return 0;
1298}
1299
1300static int lowpan_control_open(struct inode *inode, struct file *file)
1301{
1302        return single_open(file, lowpan_control_show, inode->i_private);
1303}
1304
1305static const struct file_operations lowpan_control_fops = {
1306        .open           = lowpan_control_open,
1307        .read           = seq_read,
1308        .write          = lowpan_control_write,
1309        .llseek         = seq_lseek,
1310        .release        = single_release,
1311};
1312
1313static void disconnect_devices(void)
1314{
1315        struct lowpan_btle_dev *entry, *tmp, *new_dev;
1316        struct list_head devices;
1317
1318        INIT_LIST_HEAD(&devices);
1319
1320        /* We make a separate list of devices because the unregister_netdev()
1321         * will call device_event() which will also want to modify the same
1322         * devices list.
1323         */
1324
1325        rcu_read_lock();
1326
1327        list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
1328                new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
1329                if (!new_dev)
1330                        break;
1331
1332                new_dev->netdev = entry->netdev;
1333                INIT_LIST_HEAD(&new_dev->list);
1334
1335                list_add_rcu(&new_dev->list, &devices);
1336        }
1337
1338        rcu_read_unlock();
1339
1340        list_for_each_entry_safe(entry, tmp, &devices, list) {
1341                ifdown(entry->netdev);
1342                BT_DBG("Unregistering netdev %s %p",
1343                       entry->netdev->name, entry->netdev);
1344                lowpan_unregister_netdev(entry->netdev);
1345                kfree(entry);
1346        }
1347}
1348
1349static int device_event(struct notifier_block *unused,
1350                        unsigned long event, void *ptr)
1351{
1352        struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
1353        struct lowpan_btle_dev *entry;
1354
1355        if (netdev->type != ARPHRD_6LOWPAN)
1356                return NOTIFY_DONE;
1357
1358        switch (event) {
1359        case NETDEV_UNREGISTER:
1360                spin_lock(&devices_lock);
1361                list_for_each_entry(entry, &bt_6lowpan_devices, list) {
1362                        if (entry->netdev == netdev) {
1363                                BT_DBG("Unregistered netdev %s %p",
1364                                       netdev->name, netdev);
1365                                list_del(&entry->list);
1366                                break;
1367                        }
1368                }
1369                spin_unlock(&devices_lock);
1370                break;
1371        }
1372
1373        return NOTIFY_DONE;
1374}
1375
1376static struct notifier_block bt_6lowpan_dev_notifier = {
1377        .notifier_call = device_event,
1378};
1379
1380static int __init bt_6lowpan_init(void)
1381{
1382        lowpan_enable_debugfs = debugfs_create_file("6lowpan_enable", 0644,
1383                                                    bt_debugfs, NULL,
1384                                                    &lowpan_enable_fops);
1385        lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
1386                                                     bt_debugfs, NULL,
1387                                                     &lowpan_control_fops);
1388
1389        return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
1390}
1391
1392static void __exit bt_6lowpan_exit(void)
1393{
1394        debugfs_remove(lowpan_enable_debugfs);
1395        debugfs_remove(lowpan_control_debugfs);
1396
1397        if (listen_chan) {
1398                l2cap_chan_close(listen_chan, 0);
1399                l2cap_chan_put(listen_chan);
1400        }
1401
1402        disconnect_devices();
1403
1404        unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
1405}
1406
1407module_init(bt_6lowpan_init);
1408module_exit(bt_6lowpan_exit);
1409
1410MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
1411MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
1412MODULE_VERSION(VERSION);
1413MODULE_LICENSE("GPL");
1414