Pileus Git - ~andy/linux/blob - net/ieee802154/6lowpan.c

   1 /*
   2  * Copyright 2011, Siemens AG
   3  * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
   4  */
   5
   6 /*
   7  * Based on patches from Jon Smirl <jonsmirl@gmail.com>
   8  * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2
  12  * as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  22  */
  23
  24 /* Jon's code is based on 6lowpan implementation for Contiki which is:
  25  * Copyright (c) 2008, Swedish Institute of Computer Science.
  26  * All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. Neither the name of the Institute nor the names of its contributors
  37  *    may be used to endorse or promote products derived from this software
  38  *    without specific prior written permission.
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50  * SUCH DAMAGE.
  51  */
  52
  53 #include <linux/bitops.h>
  54 #include <linux/if_arp.h>
  55 #include <linux/module.h>
  56 #include <linux/moduleparam.h>
  57 #include <linux/netdevice.h>
  58 #include <net/af_ieee802154.h>
  59 #include <net/ieee802154.h>
  60 #include <net/ieee802154_netdev.h>
  61 #include <net/ipv6.h>
  62
  63 #include "6lowpan.h"
  64
  65 static LIST_HEAD(lowpan_devices);
  66
  67 /* private device info */
  68 struct lowpan_dev_info {
  69         struct net_device       *real_dev; /* real WPAN device ptr */
  70         struct mutex            dev_list_mtx; /* mutex for list ops */
  71         unsigned short          fragment_tag;
  72 };
  73
  74 struct lowpan_dev_record {
  75         struct net_device *ldev;
  76         struct list_head list;
  77 };
  78
  79 struct lowpan_fragment {
  80         struct sk_buff          *skb;           /* skb to be assembled */
  81         u16                     length;         /* length to be assemled */
  82         u32                     bytes_rcv;      /* bytes received */
  83         u16                     tag;            /* current fragment tag */
  84         struct timer_list       timer;          /* assembling timer */
  85         struct list_head        list;           /* fragments list */
  86 };
  87
  88 static LIST_HEAD(lowpan_fragments);
  89 static DEFINE_SPINLOCK(flist_lock);
  90
  91 static inline struct
  92 lowpan_dev_info *lowpan_dev_info(const struct net_device *dev)
  93 {
  94         return netdev_priv(dev);
  95 }
  96
  97 static inline void lowpan_address_flip(u8 *src, u8 *dest)
  98 {
  99         int i;
 100         for (i = 0; i < IEEE802154_ADDR_LEN; i++)
 101                 (dest)[IEEE802154_ADDR_LEN - i - 1] = (src)[i];
 102 }
 103
 104 static int lowpan_header_create(struct sk_buff *skb,
 105                            struct net_device *dev,
 106                            unsigned short type, const void *_daddr,
 107                            const void *_saddr, unsigned int len)
 108 {
 109         const u8 *saddr = _saddr;
 110         const u8 *daddr = _daddr;
 111         struct ieee802154_addr sa, da;
 112
 113         /* TODO:
 114          * if this package isn't ipv6 one, where should it be routed?
 115          */
 116         if (type != ETH_P_IPV6)
 117                 return 0;
 118
 119         if (!saddr)
 120                 saddr = dev->dev_addr;
 121
 122         raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);
 123         raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);
 124
 125         lowpan_header_compress(skb, dev, type, daddr, saddr, len);
 126
 127         /*
 128          * NOTE1: I'm still unsure about the fact that compression and WPAN
 129          * header are created here and not later in the xmit. So wait for
 130          * an opinion of net maintainers.
 131          */
 132         /*
 133          * NOTE2: to be absolutely correct, we must derive PANid information
 134          * from MAC subif of the 'dev' and 'real_dev' network devices, but
 135          * this isn't implemented in mainline yet, so currently we assign 0xff
 136          */
 137         mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
 138         mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
 139
 140         /* prepare wpan address data */
 141         sa.addr_type = IEEE802154_ADDR_LONG;
 142         sa.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);
 143
 144         memcpy(&(sa.hwaddr), saddr, 8);
 145         /* intra-PAN communications */
 146         da.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);
 147
 148         /*
 149          * if the destination address is the broadcast address, use the
 150          * corresponding short address
 151          */
 152         if (lowpan_is_addr_broadcast(daddr)) {
 153                 da.addr_type = IEEE802154_ADDR_SHORT;
 154                 da.short_addr = IEEE802154_ADDR_BROADCAST;
 155         } else {
 156                 da.addr_type = IEEE802154_ADDR_LONG;
 157                 memcpy(&(da.hwaddr), daddr, IEEE802154_ADDR_LEN);
 158
 159                 /* request acknowledgment */
 160                 mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
 161         }
 162
 163         return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
 164                         type, (void *)&da, (void *)&sa, skb->len);
 165 }
 166
 167 static int lowpan_give_skb_to_devices(struct sk_buff *skb,
 168                                         struct net_device *dev)
 169 {
 170         struct lowpan_dev_record *entry;
 171         struct sk_buff *skb_cp;
 172         int stat = NET_RX_SUCCESS;
 173
 174         rcu_read_lock();
 175         list_for_each_entry_rcu(entry, &lowpan_devices, list)
 176                 if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
 177                         skb_cp = skb_copy(skb, GFP_ATOMIC);
 178                         if (!skb_cp) {
 179                                 stat = -ENOMEM;
 180                                 break;
 181                         }
 182
 183                         skb_cp->dev = entry->ldev;
 184                         stat = netif_rx(skb_cp);
 185                 }
 186         rcu_read_unlock();
 187
 188         return stat;
 189 }
 190
 191 static void lowpan_fragment_timer_expired(unsigned long entry_addr)
 192 {
 193         struct lowpan_fragment *entry = (struct lowpan_fragment *)entry_addr;
 194
 195         pr_debug("timer expired for frame with tag %d\n", entry->tag);
 196
 197         list_del(&entry->list);
 198         dev_kfree_skb(entry->skb);
 199         kfree(entry);
 200 }
 201
 202 static struct lowpan_fragment *
 203 lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag)
 204 {
 205         struct lowpan_fragment *frame;
 206
 207         frame = kzalloc(sizeof(struct lowpan_fragment),
 208                         GFP_ATOMIC);
 209         if (!frame)
 210                 goto frame_err;
 211
 212         INIT_LIST_HEAD(&frame->list);
 213
 214         frame->length = len;
 215         frame->tag = tag;
 216
 217         /* allocate buffer for frame assembling */
 218         frame->skb = netdev_alloc_skb_ip_align(skb->dev, frame->length +
 219                                                sizeof(struct ipv6hdr));
 220
 221         if (!frame->skb)
 222                 goto skb_err;
 223
 224         frame->skb->priority = skb->priority;
 225
 226         /* reserve headroom for uncompressed ipv6 header */
 227         skb_reserve(frame->skb, sizeof(struct ipv6hdr));
 228         skb_put(frame->skb, frame->length);
 229
 230         /* copy the first control block to keep a
 231          * trace of the link-layer addresses in case
 232          * of a link-local compressed address
 233          */
 234         memcpy(frame->skb->cb, skb->cb, sizeof(skb->cb));
 235
 236         init_timer(&frame->timer);
 237         /* time out is the same as for ipv6 - 60 sec */
 238         frame->timer.expires = jiffies + LOWPAN_FRAG_TIMEOUT;
 239         frame->timer.data = (unsigned long)frame;
 240         frame->timer.function = lowpan_fragment_timer_expired;
 241
 242         add_timer(&frame->timer);
 243
 244         list_add_tail(&frame->list, &lowpan_fragments);
 245
 246         return frame;
 247
 248 skb_err:
 249         kfree(frame);
 250 frame_err:
 251         return NULL;
 252 }
 253
 254 static int process_data(struct sk_buff *skb)
 255 {
 256         u8 iphc0, iphc1;
 257         const struct ieee802154_addr *_saddr, *_daddr;
 258
 259         raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
 260         /* at least two bytes will be used for the encoding */
 261         if (skb->len < 2)
 262                 goto drop;
 263
 264         if (lowpan_fetch_skb_u8(skb, &iphc0))
 265                 goto drop;
 266
 267         /* fragments assembling */
 268         switch (iphc0 & LOWPAN_DISPATCH_MASK) {
 269         case LOWPAN_DISPATCH_FRAG1:
 270         case LOWPAN_DISPATCH_FRAGN:
 271         {
 272                 struct lowpan_fragment *frame;
 273                 /* slen stores the rightmost 8 bits of the 11 bits length */
 274                 u8 slen, offset = 0;
 275                 u16 len, tag;
 276                 bool found = false;
 277
 278                 if (lowpan_fetch_skb_u8(skb, &slen) || /* frame length */
 279                     lowpan_fetch_skb_u16(skb, &tag))  /* fragment tag */
 280                         goto drop;
 281
 282                 /* adds the 3 MSB to the 8 LSB to retrieve the 11 bits length */
 283                 len = ((iphc0 & 7) << 8) | slen;
 284
 285                 if ((iphc0 & LOWPAN_DISPATCH_MASK) == LOWPAN_DISPATCH_FRAG1) {
 286                         pr_debug("%s received a FRAG1 packet (tag: %d, "
 287                                  "size of the entire IP packet: %d)",
 288                                  __func__, tag, len);
 289                 } else { /* FRAGN */
 290                         if (lowpan_fetch_skb_u8(skb, &offset))
 291                                 goto unlock_and_drop;
 292                         pr_debug("%s received a FRAGN packet (tag: %d, "
 293                                  "size of the entire IP packet: %d, "
 294                                  "offset: %d)", __func__, tag, len, offset * 8);
 295                 }
 296
 297                 /*
 298                  * check if frame assembling with the same tag is
 299                  * already in progress
 300                  */
 301                 spin_lock_bh(&flist_lock);
 302
 303                 list_for_each_entry(frame, &lowpan_fragments, list)
 304                         if (frame->tag == tag) {
 305                                 found = true;
 306                                 break;
 307                         }
 308
 309                 /* alloc new frame structure */
 310                 if (!found) {
 311                         pr_debug("%s first fragment received for tag %d, "
 312                                  "begin packet reassembly", __func__, tag);
 313                         frame = lowpan_alloc_new_frame(skb, len, tag);
 314                         if (!frame)
 315                                 goto unlock_and_drop;
 316                 }
 317
 318                 /* if payload fits buffer, copy it */
 319                 if (likely((offset * 8 + skb->len) <= frame->length))
 320                         skb_copy_to_linear_data_offset(frame->skb, offset * 8,
 321                                                         skb->data, skb->len);
 322                 else
 323                         goto unlock_and_drop;
 324
 325                 frame->bytes_rcv += skb->len;
 326
 327                 /* frame assembling complete */
 328                 if ((frame->bytes_rcv == frame->length) &&
 329                      frame->timer.expires > jiffies) {
 330                         /* if timer haven't expired - first of all delete it */
 331                         del_timer_sync(&frame->timer);
 332                         list_del(&frame->list);
 333                         spin_unlock_bh(&flist_lock);
 334
 335                         pr_debug("%s successfully reassembled fragment "
 336                                  "(tag %d)", __func__, tag);
 337
 338                         dev_kfree_skb(skb);
 339                         skb = frame->skb;
 340                         kfree(frame);
 341
 342                         if (lowpan_fetch_skb_u8(skb, &iphc0))
 343                                 goto drop;
 344
 345                         break;
 346                 }
 347                 spin_unlock_bh(&flist_lock);
 348
 349                 return kfree_skb(skb), 0;
 350         }
 351         default:
 352                 break;
 353         }
 354
 355         if (lowpan_fetch_skb_u8(skb, &iphc1))
 356                 goto drop;
 357
 358         _saddr = &mac_cb(skb)->sa;
 359         _daddr = &mac_cb(skb)->da;
 360
 361         return lowpan_process_data(skb, skb->dev, (u8 *)_saddr->hwaddr,
 362                                 _saddr->addr_type, IEEE802154_ADDR_LEN,
 363                                 (u8 *)_daddr->hwaddr, _daddr->addr_type,
 364                                 IEEE802154_ADDR_LEN, iphc0, iphc1,
 365                                 lowpan_give_skb_to_devices);
 366
 367 unlock_and_drop:
 368         spin_unlock_bh(&flist_lock);
 369 drop:
 370         kfree_skb(skb);
 371         return -EINVAL;
 372 }
 373
 374 static int lowpan_set_address(struct net_device *dev, void *p)
 375 {
 376         struct sockaddr *sa = p;
 377
 378         if (netif_running(dev))
 379                 return -EBUSY;
 380
 381         /* TODO: validate addr */
 382         memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 383
 384         return 0;
 385 }
 386
 387 static int
 388 lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
 389                         int mlen, int plen, int offset, int type)
 390 {
 391         struct sk_buff *frag;
 392         int hlen;
 393
 394         hlen = (type == LOWPAN_DISPATCH_FRAG1) ?
 395                         LOWPAN_FRAG1_HEAD_SIZE : LOWPAN_FRAGN_HEAD_SIZE;
 396
 397         raw_dump_inline(__func__, "6lowpan fragment header", head, hlen);
 398
 399         frag = netdev_alloc_skb(skb->dev,
 400                                 hlen + mlen + plen + IEEE802154_MFR_SIZE);
 401         if (!frag)
 402                 return -ENOMEM;
 403
 404         frag->priority = skb->priority;
 405
 406         /* copy header, MFR and payload */
 407         skb_put(frag, mlen);
 408         skb_copy_to_linear_data(frag, skb_mac_header(skb), mlen);
 409
 410         skb_put(frag, hlen);
 411         skb_copy_to_linear_data_offset(frag, mlen, head, hlen);
 412
 413         skb_put(frag, plen);
 414         skb_copy_to_linear_data_offset(frag, mlen + hlen,
 415                                        skb_network_header(skb) + offset, plen);
 416
 417         raw_dump_table(__func__, " raw fragment dump", frag->data, frag->len);
 418
 419         return dev_queue_xmit(frag);
 420 }
 421
 422 static int
 423 lowpan_skb_fragmentation(struct sk_buff *skb, struct net_device *dev)
 424 {
 425         int  err, header_length, payload_length, tag, offset = 0;
 426         u8 head[5];
 427
 428         header_length = skb->mac_len;
 429         payload_length = skb->len - header_length;
 430         tag = lowpan_dev_info(dev)->fragment_tag++;
 431
 432         /* first fragment header */
 433         head[0] = LOWPAN_DISPATCH_FRAG1 | ((payload_length >> 8) & 0x7);
 434         head[1] = payload_length & 0xff;
 435         head[2] = tag >> 8;
 436         head[3] = tag & 0xff;
 437
 438         err = lowpan_fragment_xmit(skb, head, header_length, LOWPAN_FRAG_SIZE,
 439                                    0, LOWPAN_DISPATCH_FRAG1);
 440
 441         if (err) {
 442                 pr_debug("%s unable to send FRAG1 packet (tag: %d)",
 443                          __func__, tag);
 444                 goto exit;
 445         }
 446
 447         offset = LOWPAN_FRAG_SIZE;
 448
 449         /* next fragment header */
 450         head[0] &= ~LOWPAN_DISPATCH_FRAG1;
 451         head[0] |= LOWPAN_DISPATCH_FRAGN;
 452
 453         while (payload_length - offset > 0) {
 454                 int len = LOWPAN_FRAG_SIZE;
 455
 456                 head[4] = offset / 8;
 457
 458                 if (payload_length - offset < len)
 459                         len = payload_length - offset;
 460
 461                 err = lowpan_fragment_xmit(skb, head, header_length,
 462                                            len, offset, LOWPAN_DISPATCH_FRAGN);
 463                 if (err) {
 464                         pr_debug("%s unable to send a subsequent FRAGN packet "
 465                                  "(tag: %d, offset: %d", __func__, tag, offset);
 466                         goto exit;
 467                 }
 468
 469                 offset += len;
 470         }
 471
 472 exit:
 473         return err;
 474 }
 475
 476 static netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
 477 {
 478         int err = -1;
 479
 480         pr_debug("package xmit\n");
 481
 482         skb->dev = lowpan_dev_info(dev)->real_dev;
 483         if (skb->dev == NULL) {
 484                 pr_debug("ERROR: no real wpan device found\n");
 485                 goto error;
 486         }
 487
 488         /* Send directly if less than the MTU minus the 2 checksum bytes. */
 489         if (skb->len <= IEEE802154_MTU - IEEE802154_MFR_SIZE) {
 490                 err = dev_queue_xmit(skb);
 491                 goto out;
 492         }
 493
 494         pr_debug("frame is too big, fragmentation is needed\n");
 495         err = lowpan_skb_fragmentation(skb, dev);
 496 error:
 497         dev_kfree_skb(skb);
 498 out:
 499         if (err)
 500                 pr_debug("ERROR: xmit failed\n");
 501
 502         return (err < 0) ? NET_XMIT_DROP : err;
 503 }
 504
 505 static struct wpan_phy *lowpan_get_phy(const struct net_device *dev)
 506 {
 507         struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
 508         return ieee802154_mlme_ops(real_dev)->get_phy(real_dev);
 509 }
 510
 511 static u16 lowpan_get_pan_id(const struct net_device *dev)
 512 {
 513         struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
 514         return ieee802154_mlme_ops(real_dev)->get_pan_id(real_dev);
 515 }
 516
 517 static u16 lowpan_get_short_addr(const struct net_device *dev)
 518 {
 519         struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
 520         return ieee802154_mlme_ops(real_dev)->get_short_addr(real_dev);
 521 }
 522
 523 static u8 lowpan_get_dsn(const struct net_device *dev)
 524 {
 525         struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
 526         return ieee802154_mlme_ops(real_dev)->get_dsn(real_dev);
 527 }
 528
 529 static struct header_ops lowpan_header_ops = {
 530         .create = lowpan_header_create,
 531 };
 532
 533 static struct lock_class_key lowpan_tx_busylock;
 534 static struct lock_class_key lowpan_netdev_xmit_lock_key;
 535
 536 static void lowpan_set_lockdep_class_one(struct net_device *dev,
 537                                          struct netdev_queue *txq,
 538                                          void *_unused)
 539 {
 540         lockdep_set_class(&txq->_xmit_lock,
 541                           &lowpan_netdev_xmit_lock_key);
 542 }
 543
 544
 545 static int lowpan_dev_init(struct net_device *dev)
 546 {
 547         netdev_for_each_tx_queue(dev, lowpan_set_lockdep_class_one, NULL);
 548         dev->qdisc_tx_busylock = &lowpan_tx_busylock;
 549         return 0;
 550 }
 551
 552 static const struct net_device_ops lowpan_netdev_ops = {
 553         .ndo_init               = lowpan_dev_init,
 554         .ndo_start_xmit         = lowpan_xmit,
 555         .ndo_set_mac_address    = lowpan_set_address,
 556 };
 557
 558 static struct ieee802154_mlme_ops lowpan_mlme = {
 559         .get_pan_id = lowpan_get_pan_id,
 560         .get_phy = lowpan_get_phy,
 561         .get_short_addr = lowpan_get_short_addr,
 562         .get_dsn = lowpan_get_dsn,
 563 };
 564
 565 static void lowpan_setup(struct net_device *dev)
 566 {
 567         dev->addr_len           = IEEE802154_ADDR_LEN;
 568         memset(dev->broadcast, 0xff, IEEE802154_ADDR_LEN);
 569         dev->type               = ARPHRD_IEEE802154;
 570         /* Frame Control + Sequence Number + Address fields + Security Header */
 571         dev->hard_header_len    = 2 + 1 + 20 + 14;
 572         dev->needed_tailroom    = 2; /* FCS */
 573         dev->mtu                = 1281;
 574         dev->tx_queue_len       = 0;
 575         dev->flags              = IFF_BROADCAST | IFF_MULTICAST;
 576         dev->watchdog_timeo     = 0;
 577
 578         dev->netdev_ops         = &lowpan_netdev_ops;
 579         dev->header_ops         = &lowpan_header_ops;
 580         dev->ml_priv            = &lowpan_mlme;
 581         dev->destructor         = free_netdev;
 582 }
 583
 584 static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[])
 585 {
 586         if (tb[IFLA_ADDRESS]) {
 587                 if (nla_len(tb[IFLA_ADDRESS]) != IEEE802154_ADDR_LEN)
 588                         return -EINVAL;
 589         }
 590         return 0;
 591 }
 592
 593 static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
 594         struct packet_type *pt, struct net_device *orig_dev)
 595 {
 596         struct sk_buff *local_skb;
 597
 598         if (!netif_running(dev))
 599                 goto drop;
 600
 601         if (dev->type != ARPHRD_IEEE802154)
 602                 goto drop;
 603
 604         /* check that it's our buffer */
 605         if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
 606                 /* Copy the packet so that the IPv6 header is
 607                  * properly aligned.
 608                  */
 609                 local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
 610                                             skb_tailroom(skb), GFP_ATOMIC);
 611                 if (!local_skb)
 612                         goto drop;
 613
 614                 local_skb->protocol = htons(ETH_P_IPV6);
 615                 local_skb->pkt_type = PACKET_HOST;
 616
 617                 /* Pull off the 1-byte of 6lowpan header. */
 618                 skb_pull(local_skb, 1);
 619
 620                 lowpan_give_skb_to_devices(local_skb, NULL);
 621
 622                 kfree_skb(local_skb);
 623                 kfree_skb(skb);
 624         } else {
 625                 switch (skb->data[0] & 0xe0) {
 626                 case LOWPAN_DISPATCH_IPHC:      /* ipv6 datagram */
 627                 case LOWPAN_DISPATCH_FRAG1:     /* first fragment header */
 628                 case LOWPAN_DISPATCH_FRAGN:     /* next fragments headers */
 629                         local_skb = skb_clone(skb, GFP_ATOMIC);
 630                         if (!local_skb)
 631                                 goto drop;
 632                         process_data(local_skb);
 633
 634                         kfree_skb(skb);
 635                         break;
 636                 default:
 637                         break;
 638                 }
 639         }
 640
 641         return NET_RX_SUCCESS;
 642
 643 drop:
 644         kfree_skb(skb);
 645         return NET_RX_DROP;
 646 }
 647
 648 static int lowpan_newlink(struct net *src_net, struct net_device *dev,
 649                           struct nlattr *tb[], struct nlattr *data[])
 650 {
 651         struct net_device *real_dev;
 652         struct lowpan_dev_record *entry;
 653
 654         pr_debug("adding new link\n");
 655
 656         if (!tb[IFLA_LINK])
 657                 return -EINVAL;
 658         /* find and hold real wpan device */
 659         real_dev = dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
 660         if (!real_dev)
 661                 return -ENODEV;
 662         if (real_dev->type != ARPHRD_IEEE802154) {
 663                 dev_put(real_dev);
 664                 return -EINVAL;
 665         }
 666
 667         lowpan_dev_info(dev)->real_dev = real_dev;
 668         lowpan_dev_info(dev)->fragment_tag = 0;
 669         mutex_init(&lowpan_dev_info(dev)->dev_list_mtx);
 670
 671         entry = kzalloc(sizeof(struct lowpan_dev_record), GFP_KERNEL);
 672         if (!entry) {
 673                 dev_put(real_dev);
 674                 lowpan_dev_info(dev)->real_dev = NULL;
 675                 return -ENOMEM;
 676         }
 677
 678         entry->ldev = dev;
 679
 680         /* Set the lowpan harware address to the wpan hardware address. */
 681         memcpy(dev->dev_addr, real_dev->dev_addr, IEEE802154_ADDR_LEN);
 682
 683         mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
 684         INIT_LIST_HEAD(&entry->list);
 685         list_add_tail(&entry->list, &lowpan_devices);
 686         mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);
 687
 688         register_netdevice(dev);
 689
 690         return 0;
 691 }
 692
 693 static void lowpan_dellink(struct net_device *dev, struct list_head *head)
 694 {
 695         struct lowpan_dev_info *lowpan_dev = lowpan_dev_info(dev);
 696         struct net_device *real_dev = lowpan_dev->real_dev;
 697         struct lowpan_dev_record *entry, *tmp;
 698
 699         ASSERT_RTNL();
 700
 701         mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
 702         list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
 703                 if (entry->ldev == dev) {
 704                         list_del(&entry->list);
 705                         kfree(entry);
 706                 }
 707         }
 708         mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);
 709
 710         mutex_destroy(&lowpan_dev_info(dev)->dev_list_mtx);
 711
 712         unregister_netdevice_queue(dev, head);
 713
 714         dev_put(real_dev);
 715 }
 716
 717 static struct rtnl_link_ops lowpan_link_ops __read_mostly = {
 718         .kind           = "lowpan",
 719         .priv_size      = sizeof(struct lowpan_dev_info),
 720         .setup          = lowpan_setup,
 721         .newlink        = lowpan_newlink,
 722         .dellink        = lowpan_dellink,
 723         .validate       = lowpan_validate,
 724 };
 725
 726 static inline int __init lowpan_netlink_init(void)
 727 {
 728         return rtnl_link_register(&lowpan_link_ops);
 729 }
 730
 731 static inline void lowpan_netlink_fini(void)
 732 {
 733         rtnl_link_unregister(&lowpan_link_ops);
 734 }
 735
 736 static int lowpan_device_event(struct notifier_block *unused,
 737                                unsigned long event, void *ptr)
 738 {
 739         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 740         LIST_HEAD(del_list);
 741         struct lowpan_dev_record *entry, *tmp;
 742
 743         if (dev->type != ARPHRD_IEEE802154)
 744                 goto out;
 745
 746         if (event == NETDEV_UNREGISTER) {
 747                 list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
 748                         if (lowpan_dev_info(entry->ldev)->real_dev == dev)
 749                                 lowpan_dellink(entry->ldev, &del_list);
 750                 }
 751
 752                 unregister_netdevice_many(&del_list);
 753         }
 754
 755 out:
 756         return NOTIFY_DONE;
 757 }
 758
 759 static struct notifier_block lowpan_dev_notifier = {
 760         .notifier_call = lowpan_device_event,
 761 };
 762
 763 static struct packet_type lowpan_packet_type = {
 764         .type = __constant_htons(ETH_P_IEEE802154),
 765         .func = lowpan_rcv,
 766 };
 767
 768 static int __init lowpan_init_module(void)
 769 {
 770         int err = 0;
 771
 772         err = lowpan_netlink_init();
 773         if (err < 0)
 774                 goto out;
 775
 776         dev_add_pack(&lowpan_packet_type);
 777
 778         err = register_netdevice_notifier(&lowpan_dev_notifier);
 779         if (err < 0) {
 780                 dev_remove_pack(&lowpan_packet_type);
 781                 lowpan_netlink_fini();
 782         }
 783 out:
 784         return err;
 785 }
 786
 787 static void __exit lowpan_cleanup_module(void)
 788 {
 789         struct lowpan_fragment *frame, *tframe;
 790
 791         lowpan_netlink_fini();
 792
 793         dev_remove_pack(&lowpan_packet_type);
 794
 795         unregister_netdevice_notifier(&lowpan_dev_notifier);
 796
 797         /* Now 6lowpan packet_type is removed, so no new fragments are
 798          * expected on RX, therefore that's the time to clean incomplete
 799          * fragments.
 800          */
 801         spin_lock_bh(&flist_lock);
 802         list_for_each_entry_safe(frame, tframe, &lowpan_fragments, list) {
 803                 del_timer_sync(&frame->timer);
 804                 list_del(&frame->list);
 805                 dev_kfree_skb(frame->skb);
 806                 kfree(frame);
 807         }
 808         spin_unlock_bh(&flist_lock);
 809 }
 810
 811 module_init(lowpan_init_module);
 812 module_exit(lowpan_cleanup_module);
 813 MODULE_LICENSE("GPL");
 814 MODULE_ALIAS_RTNL_LINK("lowpan");