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 /* TTL uncompression values */
  66 static const u8 lowpan_ttl_values[] = {0, 1, 64, 255};
  67
  68 static LIST_HEAD(lowpan_devices);
  69
  70 /* private device info */
  71 struct lowpan_dev_info {
  72         struct net_device       *real_dev; /* real WPAN device ptr */
  73         struct mutex            dev_list_mtx; /* mutex for list ops */
  74         unsigned short          fragment_tag;
  75 };
  76
  77 struct lowpan_dev_record {
  78         struct net_device *ldev;
  79         struct list_head list;
  80 };
  81
  82 struct lowpan_fragment {
  83         struct sk_buff          *skb;           /* skb to be assembled */
  84         u16                     length;         /* length to be assemled */
  85         u32                     bytes_rcv;      /* bytes received */
  86         u16                     tag;            /* current fragment tag */
  87         struct timer_list       timer;          /* assembling timer */
  88         struct list_head        list;           /* fragments list */
  89 };
  90
  91 static LIST_HEAD(lowpan_fragments);
  92 static DEFINE_SPINLOCK(flist_lock);
  93
  94 static inline struct
  95 lowpan_dev_info *lowpan_dev_info(const struct net_device *dev)
  96 {
  97         return netdev_priv(dev);
  98 }
  99
 100 static inline void lowpan_address_flip(u8 *src, u8 *dest)
 101 {
 102         int i;
 103         for (i = 0; i < IEEE802154_ADDR_LEN; i++)
 104                 (dest)[IEEE802154_ADDR_LEN - i - 1] = (src)[i];
 105 }
 106
 107 /* list of all 6lowpan devices, uses for package delivering */
 108 /* print data in line */
 109 static inline void lowpan_raw_dump_inline(const char *caller, char *msg,
 110                                    unsigned char *buf, int len)
 111 {
 112 #ifdef DEBUG
 113         if (msg)
 114                 pr_debug("(%s) %s: ", caller, msg);
 115         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE,
 116                        16, 1, buf, len, false);
 117 #endif /* DEBUG */
 118 }
 119
 120 /*
 121  * print data in a table format:
 122  *
 123  * addr: xx xx xx xx xx xx
 124  * addr: xx xx xx xx xx xx
 125  * ...
 126  */
 127 static inline void lowpan_raw_dump_table(const char *caller, char *msg,
 128                                    unsigned char *buf, int len)
 129 {
 130 #ifdef DEBUG
 131         if (msg)
 132                 pr_debug("(%s) %s:\n", caller, msg);
 133         print_hex_dump(KERN_DEBUG, "\t", DUMP_PREFIX_OFFSET,
 134                        16, 1, buf, len, false);
 135 #endif /* DEBUG */
 136 }
 137
 138 static u8
 139 lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift, const struct in6_addr *ipaddr,
 140                  const unsigned char *lladdr)
 141 {
 142         u8 val = 0;
 143
 144         if (is_addr_mac_addr_based(ipaddr, lladdr))
 145                 val = 3; /* 0-bits */
 146         else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
 147                 /* compress IID to 16 bits xxxx::XXXX */
 148                 memcpy(*hc06_ptr, &ipaddr->s6_addr16[7], 2);
 149                 *hc06_ptr += 2;
 150                 val = 2; /* 16-bits */
 151         } else {
 152                 /* do not compress IID => xxxx::IID */
 153                 memcpy(*hc06_ptr, &ipaddr->s6_addr16[4], 8);
 154                 *hc06_ptr += 8;
 155                 val = 1; /* 64-bits */
 156         }
 157
 158         return rol8(val, shift);
 159 }
 160
 161 /*
 162  * Uncompress address function for source and
 163  * destination address(non-multicast).
 164  *
 165  * address_mode is sam value or dam value.
 166  */
 167 static int
 168 lowpan_uncompress_addr(struct sk_buff *skb,
 169                 struct in6_addr *ipaddr,
 170                 const u8 address_mode,
 171                 const struct ieee802154_addr *lladdr)
 172 {
 173         bool fail;
 174
 175         switch (address_mode) {
 176         case LOWPAN_IPHC_ADDR_00:
 177                 /* for global link addresses */
 178                 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
 179                 break;
 180         case LOWPAN_IPHC_ADDR_01:
 181                 /* fe:80::XXXX:XXXX:XXXX:XXXX */
 182                 ipaddr->s6_addr[0] = 0xFE;
 183                 ipaddr->s6_addr[1] = 0x80;
 184                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
 185                 break;
 186         case LOWPAN_IPHC_ADDR_02:
 187                 /* fe:80::ff:fe00:XXXX */
 188                 ipaddr->s6_addr[0] = 0xFE;
 189                 ipaddr->s6_addr[1] = 0x80;
 190                 ipaddr->s6_addr[11] = 0xFF;
 191                 ipaddr->s6_addr[12] = 0xFE;
 192                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
 193                 break;
 194         case LOWPAN_IPHC_ADDR_03:
 195                 fail = false;
 196                 switch (lladdr->addr_type) {
 197                 case IEEE802154_ADDR_LONG:
 198                         /* fe:80::XXXX:XXXX:XXXX:XXXX
 199                          *        \_________________/
 200                          *              hwaddr
 201                          */
 202                         ipaddr->s6_addr[0] = 0xFE;
 203                         ipaddr->s6_addr[1] = 0x80;
 204                         memcpy(&ipaddr->s6_addr[8], lladdr->hwaddr,
 205                                         IEEE802154_ADDR_LEN);
 206                         /* second bit-flip (Universe/Local)
 207                          * is done according RFC2464
 208                          */
 209                         ipaddr->s6_addr[8] ^= 0x02;
 210                         break;
 211                 case IEEE802154_ADDR_SHORT:
 212                         /* fe:80::ff:fe00:XXXX
 213                          *                \__/
 214                          *             short_addr
 215                          *
 216                          * Universe/Local bit is zero.
 217                          */
 218                         ipaddr->s6_addr[0] = 0xFE;
 219                         ipaddr->s6_addr[1] = 0x80;
 220                         ipaddr->s6_addr[11] = 0xFF;
 221                         ipaddr->s6_addr[12] = 0xFE;
 222                         ipaddr->s6_addr16[7] = htons(lladdr->short_addr);
 223                         break;
 224                 default:
 225                         pr_debug("Invalid addr_type set\n");
 226                         return -EINVAL;
 227                 }
 228                 break;
 229         default:
 230                 pr_debug("Invalid address mode value: 0x%x\n", address_mode);
 231                 return -EINVAL;
 232         }
 233
 234         if (fail) {
 235                 pr_debug("Failed to fetch skb data\n");
 236                 return -EIO;
 237         }
 238
 239         lowpan_raw_dump_inline(NULL, "Reconstructed ipv6 addr is:\n",
 240                         ipaddr->s6_addr, 16);
 241
 242         return 0;
 243 }
 244
 245 /* Uncompress address function for source context
 246  * based address(non-multicast).
 247  */
 248 static int
 249 lowpan_uncompress_context_based_src_addr(struct sk_buff *skb,
 250                 struct in6_addr *ipaddr,
 251                 const u8 sam)
 252 {
 253         switch (sam) {
 254         case LOWPAN_IPHC_ADDR_00:
 255                 /* unspec address ::
 256                  * Do nothing, address is already ::
 257                  */
 258                 break;
 259         case LOWPAN_IPHC_ADDR_01:
 260                 /* TODO */
 261         case LOWPAN_IPHC_ADDR_02:
 262                 /* TODO */
 263         case LOWPAN_IPHC_ADDR_03:
 264                 /* TODO */
 265                 netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
 266                 return -EINVAL;
 267         default:
 268                 pr_debug("Invalid sam value: 0x%x\n", sam);
 269                 return -EINVAL;
 270         }
 271
 272         lowpan_raw_dump_inline(NULL,
 273                         "Reconstructed context based ipv6 src addr is:\n",
 274                         ipaddr->s6_addr, 16);
 275
 276         return 0;
 277 }
 278
 279 /* Uncompress function for multicast destination address,
 280  * when M bit is set.
 281  */
 282 static int
 283 lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 284                 struct in6_addr *ipaddr,
 285                 const u8 dam)
 286 {
 287         bool fail;
 288
 289         switch (dam) {
 290         case LOWPAN_IPHC_DAM_00:
 291                 /* 00:  128 bits.  The full address
 292                  * is carried in-line.
 293                  */
 294                 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
 295                 break;
 296         case LOWPAN_IPHC_DAM_01:
 297                 /* 01:  48 bits.  The address takes
 298                  * the form ffXX::00XX:XXXX:XXXX.
 299                  */
 300                 ipaddr->s6_addr[0] = 0xFF;
 301                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
 302                 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
 303                 break;
 304         case LOWPAN_IPHC_DAM_10:
 305                 /* 10:  32 bits.  The address takes
 306                  * the form ffXX::00XX:XXXX.
 307                  */
 308                 ipaddr->s6_addr[0] = 0xFF;
 309                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
 310                 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
 311                 break;
 312         case LOWPAN_IPHC_DAM_11:
 313                 /* 11:  8 bits.  The address takes
 314                  * the form ff02::00XX.
 315                  */
 316                 ipaddr->s6_addr[0] = 0xFF;
 317                 ipaddr->s6_addr[1] = 0x02;
 318                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
 319                 break;
 320         default:
 321                 pr_debug("DAM value has a wrong value: 0x%x\n", dam);
 322                 return -EINVAL;
 323         }
 324
 325         if (fail) {
 326                 pr_debug("Failed to fetch skb data\n");
 327                 return -EIO;
 328         }
 329
 330         lowpan_raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is:\n",
 331                         ipaddr->s6_addr, 16);
 332
 333         return 0;
 334 }
 335
 336 static void
 337 lowpan_compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb)
 338 {
 339         struct udphdr *uh = udp_hdr(skb);
 340
 341         if (((uh->source & LOWPAN_NHC_UDP_4BIT_MASK) ==
 342                                 LOWPAN_NHC_UDP_4BIT_PORT) &&
 343             ((uh->dest & LOWPAN_NHC_UDP_4BIT_MASK) ==
 344                                 LOWPAN_NHC_UDP_4BIT_PORT)) {
 345                 pr_debug("UDP header: both ports compression to 4 bits\n");
 346                 **hc06_ptr = LOWPAN_NHC_UDP_CS_P_11;
 347                 **(hc06_ptr + 1) = /* subtraction is faster */
 348                    (u8)((uh->dest - LOWPAN_NHC_UDP_4BIT_PORT) +
 349                        ((uh->source & LOWPAN_NHC_UDP_4BIT_PORT) << 4));
 350                 *hc06_ptr += 2;
 351         } else if ((uh->dest & LOWPAN_NHC_UDP_8BIT_MASK) ==
 352                         LOWPAN_NHC_UDP_8BIT_PORT) {
 353                 pr_debug("UDP header: remove 8 bits of dest\n");
 354                 **hc06_ptr = LOWPAN_NHC_UDP_CS_P_01;
 355                 memcpy(*hc06_ptr + 1, &uh->source, 2);
 356                 **(hc06_ptr + 3) = (u8)(uh->dest - LOWPAN_NHC_UDP_8BIT_PORT);
 357                 *hc06_ptr += 4;
 358         } else if ((uh->source & LOWPAN_NHC_UDP_8BIT_MASK) ==
 359                         LOWPAN_NHC_UDP_8BIT_PORT) {
 360                 pr_debug("UDP header: remove 8 bits of source\n");
 361                 **hc06_ptr = LOWPAN_NHC_UDP_CS_P_10;
 362                 memcpy(*hc06_ptr + 1, &uh->dest, 2);
 363                 **(hc06_ptr + 3) = (u8)(uh->source - LOWPAN_NHC_UDP_8BIT_PORT);
 364                 *hc06_ptr += 4;
 365         } else {
 366                 pr_debug("UDP header: can't compress\n");
 367                 **hc06_ptr = LOWPAN_NHC_UDP_CS_P_00;
 368                 memcpy(*hc06_ptr + 1, &uh->source, 2);
 369                 memcpy(*hc06_ptr + 3, &uh->dest, 2);
 370                 *hc06_ptr += 5;
 371         }
 372
 373         /* checksum is always inline */
 374         memcpy(*hc06_ptr, &uh->check, 2);
 375         *hc06_ptr += 2;
 376
 377         /* skip the UDP header */
 378         skb_pull(skb, sizeof(struct udphdr));
 379 }
 380
 381 static inline int lowpan_fetch_skb_u8(struct sk_buff *skb, u8 *val)
 382 {
 383         if (unlikely(!pskb_may_pull(skb, 1)))
 384                 return -EINVAL;
 385
 386         *val = skb->data[0];
 387         skb_pull(skb, 1);
 388
 389         return 0;
 390 }
 391
 392 static inline int lowpan_fetch_skb_u16(struct sk_buff *skb, u16 *val)
 393 {
 394         if (unlikely(!pskb_may_pull(skb, 2)))
 395                 return -EINVAL;
 396
 397         *val = (skb->data[0] << 8) | skb->data[1];
 398         skb_pull(skb, 2);
 399
 400         return 0;
 401 }
 402
 403 static int
 404 lowpan_uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
 405 {
 406         u8 tmp;
 407
 408         if (!uh)
 409                 goto err;
 410
 411         if (lowpan_fetch_skb_u8(skb, &tmp))
 412                 goto err;
 413
 414         if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
 415                 pr_debug("UDP header uncompression\n");
 416                 switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
 417                 case LOWPAN_NHC_UDP_CS_P_00:
 418                         memcpy(&uh->source, &skb->data[0], 2);
 419                         memcpy(&uh->dest, &skb->data[2], 2);
 420                         skb_pull(skb, 4);
 421                         break;
 422                 case LOWPAN_NHC_UDP_CS_P_01:
 423                         memcpy(&uh->source, &skb->data[0], 2);
 424                         uh->dest =
 425                            skb->data[2] + LOWPAN_NHC_UDP_8BIT_PORT;
 426                         skb_pull(skb, 3);
 427                         break;
 428                 case LOWPAN_NHC_UDP_CS_P_10:
 429                         uh->source = skb->data[0] + LOWPAN_NHC_UDP_8BIT_PORT;
 430                         memcpy(&uh->dest, &skb->data[1], 2);
 431                         skb_pull(skb, 3);
 432                         break;
 433                 case LOWPAN_NHC_UDP_CS_P_11:
 434                         uh->source =
 435                            LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] >> 4);
 436                         uh->dest =
 437                            LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] & 0x0f);
 438                         skb_pull(skb, 1);
 439                         break;
 440                 default:
 441                         pr_debug("ERROR: unknown UDP format\n");
 442                         goto err;
 443                 }
 444
 445                 pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
 446                          uh->source, uh->dest);
 447
 448                 /* copy checksum */
 449                 memcpy(&uh->check, &skb->data[0], 2);
 450                 skb_pull(skb, 2);
 451
 452                 /*
 453                  * UDP lenght needs to be infered from the lower layers
 454                  * here, we obtain the hint from the remaining size of the
 455                  * frame
 456                  */
 457                 uh->len = htons(skb->len + sizeof(struct udphdr));
 458                 pr_debug("uncompressed UDP length: src = %d", uh->len);
 459         } else {
 460                 pr_debug("ERROR: unsupported NH format\n");
 461                 goto err;
 462         }
 463
 464         return 0;
 465 err:
 466         return -EINVAL;
 467 }
 468
 469 static int lowpan_header_create(struct sk_buff *skb,
 470                            struct net_device *dev,
 471                            unsigned short type, const void *_daddr,
 472                            const void *_saddr, unsigned int len)
 473 {
 474         u8 tmp, iphc0, iphc1, *hc06_ptr;
 475         struct ipv6hdr *hdr;
 476         const u8 *saddr = _saddr;
 477         const u8 *daddr = _daddr;
 478         u8 head[100];
 479         struct ieee802154_addr sa, da;
 480
 481         /* TODO:
 482          * if this package isn't ipv6 one, where should it be routed?
 483          */
 484         if (type != ETH_P_IPV6)
 485                 return 0;
 486
 487         hdr = ipv6_hdr(skb);
 488         hc06_ptr = head + 2;
 489
 490         pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength  = %d\n"
 491                  "\tnexthdr = 0x%02x\n\thop_lim = %d\n", hdr->version,
 492                  ntohs(hdr->payload_len), hdr->nexthdr, hdr->hop_limit);
 493
 494         lowpan_raw_dump_table(__func__, "raw skb network header dump",
 495                 skb_network_header(skb), sizeof(struct ipv6hdr));
 496
 497         if (!saddr)
 498                 saddr = dev->dev_addr;
 499
 500         lowpan_raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);
 501
 502         /*
 503          * As we copy some bit-length fields, in the IPHC encoding bytes,
 504          * we sometimes use |=
 505          * If the field is 0, and the current bit value in memory is 1,
 506          * this does not work. We therefore reset the IPHC encoding here
 507          */
 508         iphc0 = LOWPAN_DISPATCH_IPHC;
 509         iphc1 = 0;
 510
 511         /* TODO: context lookup */
 512
 513         lowpan_raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);
 514
 515         /*
 516          * Traffic class, flow label
 517          * If flow label is 0, compress it. If traffic class is 0, compress it
 518          * We have to process both in the same time as the offset of traffic
 519          * class depends on the presence of version and flow label
 520          */
 521
 522         /* hc06 format of TC is ECN | DSCP , original one is DSCP | ECN */
 523         tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
 524         tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
 525
 526         if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
 527              (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
 528                 /* flow label can be compressed */
 529                 iphc0 |= LOWPAN_IPHC_FL_C;
 530                 if ((hdr->priority == 0) &&
 531                    ((hdr->flow_lbl[0] & 0xF0) == 0)) {
 532                         /* compress (elide) all */
 533                         iphc0 |= LOWPAN_IPHC_TC_C;
 534                 } else {
 535                         /* compress only the flow label */
 536                         *hc06_ptr = tmp;
 537                         hc06_ptr += 1;
 538                 }
 539         } else {
 540                 /* Flow label cannot be compressed */
 541                 if ((hdr->priority == 0) &&
 542                    ((hdr->flow_lbl[0] & 0xF0) == 0)) {
 543                         /* compress only traffic class */
 544                         iphc0 |= LOWPAN_IPHC_TC_C;
 545                         *hc06_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
 546                         memcpy(hc06_ptr + 1, &hdr->flow_lbl[1], 2);
 547                         hc06_ptr += 3;
 548                 } else {
 549                         /* compress nothing */
 550                         memcpy(hc06_ptr, &hdr, 4);
 551                         /* replace the top byte with new ECN | DSCP format */
 552                         *hc06_ptr = tmp;
 553                         hc06_ptr += 4;
 554                 }
 555         }
 556
 557         /* NOTE: payload length is always compressed */
 558
 559         /* Next Header is compress if UDP */
 560         if (hdr->nexthdr == UIP_PROTO_UDP)
 561                 iphc0 |= LOWPAN_IPHC_NH_C;
 562
 563         if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
 564                 *hc06_ptr = hdr->nexthdr;
 565                 hc06_ptr += 1;
 566         }
 567
 568         /*
 569          * Hop limit
 570          * if 1:   compress, encoding is 01
 571          * if 64:  compress, encoding is 10
 572          * if 255: compress, encoding is 11
 573          * else do not compress
 574          */
 575         switch (hdr->hop_limit) {
 576         case 1:
 577                 iphc0 |= LOWPAN_IPHC_TTL_1;
 578                 break;
 579         case 64:
 580                 iphc0 |= LOWPAN_IPHC_TTL_64;
 581                 break;
 582         case 255:
 583                 iphc0 |= LOWPAN_IPHC_TTL_255;
 584                 break;
 585         default:
 586                 *hc06_ptr = hdr->hop_limit;
 587                 hc06_ptr += 1;
 588                 break;
 589         }
 590
 591         /* source address compression */
 592         if (is_addr_unspecified(&hdr->saddr)) {
 593                 pr_debug("source address is unspecified, setting SAC\n");
 594                 iphc1 |= LOWPAN_IPHC_SAC;
 595         /* TODO: context lookup */
 596         } else if (is_addr_link_local(&hdr->saddr)) {
 597                 pr_debug("source address is link-local\n");
 598                 iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
 599                                 LOWPAN_IPHC_SAM_BIT, &hdr->saddr, saddr);
 600         } else {
 601                 pr_debug("send the full source address\n");
 602                 memcpy(hc06_ptr, &hdr->saddr.s6_addr16[0], 16);
 603                 hc06_ptr += 16;
 604         }
 605
 606         /* destination address compression */
 607         if (is_addr_mcast(&hdr->daddr)) {
 608                 pr_debug("destination address is multicast: ");
 609                 iphc1 |= LOWPAN_IPHC_M;
 610                 if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
 611                         pr_debug("compressed to 1 octet\n");
 612                         iphc1 |= LOWPAN_IPHC_DAM_11;
 613                         /* use last byte */
 614                         *hc06_ptr = hdr->daddr.s6_addr[15];
 615                         hc06_ptr += 1;
 616                 } else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
 617                         pr_debug("compressed to 4 octets\n");
 618                         iphc1 |= LOWPAN_IPHC_DAM_10;
 619                         /* second byte + the last three */
 620                         *hc06_ptr = hdr->daddr.s6_addr[1];
 621                         memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[13], 3);
 622                         hc06_ptr += 4;
 623                 } else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
 624                         pr_debug("compressed to 6 octets\n");
 625                         iphc1 |= LOWPAN_IPHC_DAM_01;
 626                         /* second byte + the last five */
 627                         *hc06_ptr = hdr->daddr.s6_addr[1];
 628                         memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[11], 5);
 629                         hc06_ptr += 6;
 630                 } else {
 631                         pr_debug("using full address\n");
 632                         iphc1 |= LOWPAN_IPHC_DAM_00;
 633                         memcpy(hc06_ptr, &hdr->daddr.s6_addr[0], 16);
 634                         hc06_ptr += 16;
 635                 }
 636         } else {
 637                 /* TODO: context lookup */
 638                 if (is_addr_link_local(&hdr->daddr)) {
 639                         pr_debug("dest address is unicast and link-local\n");
 640                         iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
 641                                 LOWPAN_IPHC_DAM_BIT, &hdr->daddr, daddr);
 642                 } else {
 643                         pr_debug("dest address is unicast: using full one\n");
 644                         memcpy(hc06_ptr, &hdr->daddr.s6_addr16[0], 16);
 645                         hc06_ptr += 16;
 646                 }
 647         }
 648
 649         /* UDP header compression */
 650         if (hdr->nexthdr == UIP_PROTO_UDP)
 651                 lowpan_compress_udp_header(&hc06_ptr, skb);
 652
 653         head[0] = iphc0;
 654         head[1] = iphc1;
 655
 656         skb_pull(skb, sizeof(struct ipv6hdr));
 657         skb_reset_transport_header(skb);
 658         memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head);
 659         skb_reset_network_header(skb);
 660
 661         lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
 662                                 skb->len);
 663
 664         /*
 665          * NOTE1: I'm still unsure about the fact that compression and WPAN
 666          * header are created here and not later in the xmit. So wait for
 667          * an opinion of net maintainers.
 668          */
 669         /*
 670          * NOTE2: to be absolutely correct, we must derive PANid information
 671          * from MAC subif of the 'dev' and 'real_dev' network devices, but
 672          * this isn't implemented in mainline yet, so currently we assign 0xff
 673          */
 674         {
 675                 mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
 676                 mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
 677
 678                 /* prepare wpan address data */
 679                 sa.addr_type = IEEE802154_ADDR_LONG;
 680                 sa.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);
 681
 682                 memcpy(&(sa.hwaddr), saddr, 8);
 683                 /* intra-PAN communications */
 684                 da.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);
 685
 686                 /*
 687                  * if the destination address is the broadcast address, use the
 688                  * corresponding short address
 689                  */
 690                 if (lowpan_is_addr_broadcast(daddr)) {
 691                         da.addr_type = IEEE802154_ADDR_SHORT;
 692                         da.short_addr = IEEE802154_ADDR_BROADCAST;
 693                 } else {
 694                         da.addr_type = IEEE802154_ADDR_LONG;
 695                         memcpy(&(da.hwaddr), daddr, IEEE802154_ADDR_LEN);
 696
 697                         /* request acknowledgment */
 698                         mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
 699                 }
 700
 701                 return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
 702                                 type, (void *)&da, (void *)&sa, skb->len);
 703         }
 704 }
 705
 706 static int lowpan_give_skb_to_devices(struct sk_buff *skb)
 707 {
 708         struct lowpan_dev_record *entry;
 709         struct sk_buff *skb_cp;
 710         int stat = NET_RX_SUCCESS;
 711
 712         rcu_read_lock();
 713         list_for_each_entry_rcu(entry, &lowpan_devices, list)
 714                 if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
 715                         skb_cp = skb_copy(skb, GFP_ATOMIC);
 716                         if (!skb_cp) {
 717                                 stat = -ENOMEM;
 718                                 break;
 719                         }
 720
 721                         skb_cp->dev = entry->ldev;
 722                         stat = netif_rx(skb_cp);
 723                 }
 724         rcu_read_unlock();
 725
 726         return stat;
 727 }
 728
 729 static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
 730 {
 731         struct sk_buff *new;
 732         int stat = NET_RX_SUCCESS;
 733
 734         new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
 735                                                                 GFP_ATOMIC);
 736         kfree_skb(skb);
 737
 738         if (!new)
 739                 return -ENOMEM;
 740
 741         skb_push(new, sizeof(struct ipv6hdr));
 742         skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
 743
 744         new->protocol = htons(ETH_P_IPV6);
 745         new->pkt_type = PACKET_HOST;
 746
 747         stat = lowpan_give_skb_to_devices(new);
 748
 749         kfree_skb(new);
 750
 751         return stat;
 752 }
 753
 754 static void lowpan_fragment_timer_expired(unsigned long entry_addr)
 755 {
 756         struct lowpan_fragment *entry = (struct lowpan_fragment *)entry_addr;
 757
 758         pr_debug("timer expired for frame with tag %d\n", entry->tag);
 759
 760         list_del(&entry->list);
 761         dev_kfree_skb(entry->skb);
 762         kfree(entry);
 763 }
 764
 765 static struct lowpan_fragment *
 766 lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag)
 767 {
 768         struct lowpan_fragment *frame;
 769
 770         frame = kzalloc(sizeof(struct lowpan_fragment),
 771                         GFP_ATOMIC);
 772         if (!frame)
 773                 goto frame_err;
 774
 775         INIT_LIST_HEAD(&frame->list);
 776
 777         frame->length = len;
 778         frame->tag = tag;
 779
 780         /* allocate buffer for frame assembling */
 781         frame->skb = netdev_alloc_skb_ip_align(skb->dev, frame->length +
 782                                                sizeof(struct ipv6hdr));
 783
 784         if (!frame->skb)
 785                 goto skb_err;
 786
 787         frame->skb->priority = skb->priority;
 788
 789         /* reserve headroom for uncompressed ipv6 header */
 790         skb_reserve(frame->skb, sizeof(struct ipv6hdr));
 791         skb_put(frame->skb, frame->length);
 792
 793         /* copy the first control block to keep a
 794          * trace of the link-layer addresses in case
 795          * of a link-local compressed address
 796          */
 797         memcpy(frame->skb->cb, skb->cb, sizeof(skb->cb));
 798
 799         init_timer(&frame->timer);
 800         /* time out is the same as for ipv6 - 60 sec */
 801         frame->timer.expires = jiffies + LOWPAN_FRAG_TIMEOUT;
 802         frame->timer.data = (unsigned long)frame;
 803         frame->timer.function = lowpan_fragment_timer_expired;
 804
 805         add_timer(&frame->timer);
 806
 807         list_add_tail(&frame->list, &lowpan_fragments);
 808
 809         return frame;
 810
 811 skb_err:
 812         kfree(frame);
 813 frame_err:
 814         return NULL;
 815 }
 816
 817 static int
 818 lowpan_process_data(struct sk_buff *skb)
 819 {
 820         struct ipv6hdr hdr = {};
 821         u8 tmp, iphc0, iphc1, num_context = 0;
 822         const struct ieee802154_addr *_saddr, *_daddr;
 823         int err;
 824
 825         lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
 826                                 skb->len);
 827         /* at least two bytes will be used for the encoding */
 828         if (skb->len < 2)
 829                 goto drop;
 830
 831         if (lowpan_fetch_skb_u8(skb, &iphc0))
 832                 goto drop;
 833
 834         /* fragments assembling */
 835         switch (iphc0 & LOWPAN_DISPATCH_MASK) {
 836         case LOWPAN_DISPATCH_FRAG1:
 837         case LOWPAN_DISPATCH_FRAGN:
 838         {
 839                 struct lowpan_fragment *frame;
 840                 /* slen stores the rightmost 8 bits of the 11 bits length */
 841                 u8 slen, offset = 0;
 842                 u16 len, tag;
 843                 bool found = false;
 844
 845                 if (lowpan_fetch_skb_u8(skb, &slen) || /* frame length */
 846                     lowpan_fetch_skb_u16(skb, &tag))  /* fragment tag */
 847                         goto drop;
 848
 849                 /* adds the 3 MSB to the 8 LSB to retrieve the 11 bits length */
 850                 len = ((iphc0 & 7) << 8) | slen;
 851
 852                 if ((iphc0 & LOWPAN_DISPATCH_MASK) == LOWPAN_DISPATCH_FRAG1) {
 853                         pr_debug("%s received a FRAG1 packet (tag: %d, "
 854                                  "size of the entire IP packet: %d)",
 855                                  __func__, tag, len);
 856                 } else { /* FRAGN */
 857                         if (lowpan_fetch_skb_u8(skb, &offset))
 858                                 goto unlock_and_drop;
 859                         pr_debug("%s received a FRAGN packet (tag: %d, "
 860                                  "size of the entire IP packet: %d, "
 861                                  "offset: %d)", __func__, tag, len, offset * 8);
 862                 }
 863
 864                 /*
 865                  * check if frame assembling with the same tag is
 866                  * already in progress
 867                  */
 868                 spin_lock_bh(&flist_lock);
 869
 870                 list_for_each_entry(frame, &lowpan_fragments, list)
 871                         if (frame->tag == tag) {
 872                                 found = true;
 873                                 break;
 874                         }
 875
 876                 /* alloc new frame structure */
 877                 if (!found) {
 878                         pr_debug("%s first fragment received for tag %d, "
 879                                  "begin packet reassembly", __func__, tag);
 880                         frame = lowpan_alloc_new_frame(skb, len, tag);
 881                         if (!frame)
 882                                 goto unlock_and_drop;
 883                 }
 884
 885                 /* if payload fits buffer, copy it */
 886                 if (likely((offset * 8 + skb->len) <= frame->length))
 887                         skb_copy_to_linear_data_offset(frame->skb, offset * 8,
 888                                                         skb->data, skb->len);
 889                 else
 890                         goto unlock_and_drop;
 891
 892                 frame->bytes_rcv += skb->len;
 893
 894                 /* frame assembling complete */
 895                 if ((frame->bytes_rcv == frame->length) &&
 896                      frame->timer.expires > jiffies) {
 897                         /* if timer haven't expired - first of all delete it */
 898                         del_timer_sync(&frame->timer);
 899                         list_del(&frame->list);
 900                         spin_unlock_bh(&flist_lock);
 901
 902                         pr_debug("%s successfully reassembled fragment "
 903                                  "(tag %d)", __func__, tag);
 904
 905                         dev_kfree_skb(skb);
 906                         skb = frame->skb;
 907                         kfree(frame);
 908
 909                         if (lowpan_fetch_skb_u8(skb, &iphc0))
 910                                 goto drop;
 911
 912                         break;
 913                 }
 914                 spin_unlock_bh(&flist_lock);
 915
 916                 return kfree_skb(skb), 0;
 917         }
 918         default:
 919                 break;
 920         }
 921
 922         if (lowpan_fetch_skb_u8(skb, &iphc1))
 923                 goto drop;
 924
 925         _saddr = &mac_cb(skb)->sa;
 926         _daddr = &mac_cb(skb)->da;
 927
 928         pr_debug("iphc0 = %02x, iphc1 = %02x\n", iphc0, iphc1);
 929
 930         /* another if the CID flag is set */
 931         if (iphc1 & LOWPAN_IPHC_CID) {
 932                 pr_debug("CID flag is set, increase header with one\n");
 933                 if (lowpan_fetch_skb_u8(skb, &num_context))
 934                         goto drop;
 935         }
 936
 937         hdr.version = 6;
 938
 939         /* Traffic Class and Flow Label */
 940         switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
 941         /*
 942          * Traffic Class and FLow Label carried in-line
 943          * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
 944          */
 945         case 0: /* 00b */
 946                 if (lowpan_fetch_skb_u8(skb, &tmp))
 947                         goto drop;
 948
 949                 memcpy(&hdr.flow_lbl, &skb->data[0], 3);
 950                 skb_pull(skb, 3);
 951                 hdr.priority = ((tmp >> 2) & 0x0f);
 952                 hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
 953                                         (hdr.flow_lbl[0] & 0x0f);
 954                 break;
 955         /*
 956          * Traffic class carried in-line
 957          * ECN + DSCP (1 byte), Flow Label is elided
 958          */
 959         case 2: /* 10b */
 960                 if (lowpan_fetch_skb_u8(skb, &tmp))
 961                         goto drop;
 962
 963                 hdr.priority = ((tmp >> 2) & 0x0f);
 964                 hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
 965                 break;
 966         /*
 967          * Flow Label carried in-line
 968          * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
 969          */
 970         case 1: /* 01b */
 971                 if (lowpan_fetch_skb_u8(skb, &tmp))
 972                         goto drop;
 973
 974                 hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
 975                 memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
 976                 skb_pull(skb, 2);
 977                 break;
 978         /* Traffic Class and Flow Label are elided */
 979         case 3: /* 11b */
 980                 break;
 981         default:
 982                 break;
 983         }
 984
 985         /* Next Header */
 986         if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
 987                 /* Next header is carried inline */
 988                 if (lowpan_fetch_skb_u8(skb, &(hdr.nexthdr)))
 989                         goto drop;
 990
 991                 pr_debug("NH flag is set, next header carried inline: %02x\n",
 992                          hdr.nexthdr);
 993         }
 994
 995         /* Hop Limit */
 996         if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I)
 997                 hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
 998         else {
 999                 if (lowpan_fetch_skb_u8(skb, &(hdr.hop_limit)))
1000                         goto drop;
1001         }
1002
1003         /* Extract SAM to the tmp variable */
1004         tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
1005
1006         if (iphc1 & LOWPAN_IPHC_SAC) {
1007                 /* Source address context based uncompression */
1008                 pr_debug("SAC bit is set. Handle context based source address.\n");
1009                 err = lowpan_uncompress_context_based_src_addr(
1010                                 skb, &hdr.saddr, tmp);
1011         } else {
1012                 /* Source address uncompression */
1013                 pr_debug("source address stateless compression\n");
1014                 err = lowpan_uncompress_addr(skb, &hdr.saddr, tmp, _saddr);
1015         }
1016
1017         /* Check on error of previous branch */
1018         if (err)
1019                 goto drop;
1020
1021         /* Extract DAM to the tmp variable */
1022         tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
1023
1024         /* check for Multicast Compression */
1025         if (iphc1 & LOWPAN_IPHC_M) {
1026                 if (iphc1 & LOWPAN_IPHC_DAC) {
1027                         pr_debug("dest: context-based mcast compression\n");
1028                         /* TODO: implement this */
1029                 } else {
1030                         err = lowpan_uncompress_multicast_daddr(
1031                                         skb, &hdr.daddr, tmp);
1032                         if (err)
1033                                 goto drop;
1034                 }
1035         } else {
1036                 pr_debug("dest: stateless compression\n");
1037                 err = lowpan_uncompress_addr(skb, &hdr.daddr, tmp, _daddr);
1038                 if (err)
1039                         goto drop;
1040         }
1041
1042         /* UDP data uncompression */
1043         if (iphc0 & LOWPAN_IPHC_NH_C) {
1044                 struct udphdr uh;
1045                 struct sk_buff *new;
1046                 if (lowpan_uncompress_udp_header(skb, &uh))
1047                         goto drop;
1048
1049                 /*
1050                  * replace the compressed UDP head by the uncompressed UDP
1051                  * header
1052                  */
1053                 new = skb_copy_expand(skb, sizeof(struct udphdr),
1054                                       skb_tailroom(skb), GFP_ATOMIC);
1055                 kfree_skb(skb);
1056
1057                 if (!new)
1058                         return -ENOMEM;
1059
1060                 skb = new;
1061
1062                 skb_push(skb, sizeof(struct udphdr));
1063                 skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));
1064
1065                 lowpan_raw_dump_table(__func__, "raw UDP header dump",
1066                                       (u8 *)&uh, sizeof(uh));
1067
1068                 hdr.nexthdr = UIP_PROTO_UDP;
1069         }
1070
1071         /* Not fragmented package */
1072         hdr.payload_len = htons(skb->len);
1073
1074         pr_debug("skb headroom size = %d, data length = %d\n",
1075                  skb_headroom(skb), skb->len);
1076
1077         pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength  = %d\n\t"
1078                  "nexthdr = 0x%02x\n\thop_lim = %d\n", hdr.version,
1079                  ntohs(hdr.payload_len), hdr.nexthdr, hdr.hop_limit);
1080
1081         lowpan_raw_dump_table(__func__, "raw header dump", (u8 *)&hdr,
1082                                                         sizeof(hdr));
1083         return lowpan_skb_deliver(skb, &hdr);
1084
1085 unlock_and_drop:
1086         spin_unlock_bh(&flist_lock);
1087 drop:
1088         kfree_skb(skb);
1089         return -EINVAL;
1090 }
1091
1092 static int lowpan_set_address(struct net_device *dev, void *p)
1093 {
1094         struct sockaddr *sa = p;
1095
1096         if (netif_running(dev))
1097                 return -EBUSY;
1098
1099         /* TODO: validate addr */
1100         memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
1101
1102         return 0;
1103 }
1104
1105 static int
1106 lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
1107                         int mlen, int plen, int offset, int type)
1108 {
1109         struct sk_buff *frag;
1110         int hlen;
1111
1112         hlen = (type == LOWPAN_DISPATCH_FRAG1) ?
1113                         LOWPAN_FRAG1_HEAD_SIZE : LOWPAN_FRAGN_HEAD_SIZE;
1114
1115         lowpan_raw_dump_inline(__func__, "6lowpan fragment header", head, hlen);
1116
1117         frag = netdev_alloc_skb(skb->dev,
1118                                 hlen + mlen + plen + IEEE802154_MFR_SIZE);
1119         if (!frag)
1120                 return -ENOMEM;
1121
1122         frag->priority = skb->priority;
1123
1124         /* copy header, MFR and payload */
1125         skb_put(frag, mlen);
1126         skb_copy_to_linear_data(frag, skb_mac_header(skb), mlen);
1127
1128         skb_put(frag, hlen);
1129         skb_copy_to_linear_data_offset(frag, mlen, head, hlen);
1130
1131         skb_put(frag, plen);
1132         skb_copy_to_linear_data_offset(frag, mlen + hlen,
1133                                        skb_network_header(skb) + offset, plen);
1134
1135         lowpan_raw_dump_table(__func__, " raw fragment dump", frag->data,
1136                                                                 frag->len);
1137
1138         return dev_queue_xmit(frag);
1139 }
1140
1141 static int
1142 lowpan_skb_fragmentation(struct sk_buff *skb, struct net_device *dev)
1143 {
1144         int  err, header_length, payload_length, tag, offset = 0;
1145         u8 head[5];
1146
1147         header_length = skb->mac_len;
1148         payload_length = skb->len - header_length;
1149         tag = lowpan_dev_info(dev)->fragment_tag++;
1150
1151         /* first fragment header */
1152         head[0] = LOWPAN_DISPATCH_FRAG1 | ((payload_length >> 8) & 0x7);
1153         head[1] = payload_length & 0xff;
1154         head[2] = tag >> 8;
1155         head[3] = tag & 0xff;
1156
1157         err = lowpan_fragment_xmit(skb, head, header_length, LOWPAN_FRAG_SIZE,
1158                                    0, LOWPAN_DISPATCH_FRAG1);
1159
1160         if (err) {
1161                 pr_debug("%s unable to send FRAG1 packet (tag: %d)",
1162                          __func__, tag);
1163                 goto exit;
1164         }
1165
1166         offset = LOWPAN_FRAG_SIZE;
1167
1168         /* next fragment header */
1169         head[0] &= ~LOWPAN_DISPATCH_FRAG1;
1170         head[0] |= LOWPAN_DISPATCH_FRAGN;
1171
1172         while (payload_length - offset > 0) {
1173                 int len = LOWPAN_FRAG_SIZE;
1174
1175                 head[4] = offset / 8;
1176
1177                 if (payload_length - offset < len)
1178                         len = payload_length - offset;
1179
1180                 err = lowpan_fragment_xmit(skb, head, header_length,
1181                                            len, offset, LOWPAN_DISPATCH_FRAGN);
1182                 if (err) {
1183                         pr_debug("%s unable to send a subsequent FRAGN packet "
1184                                  "(tag: %d, offset: %d", __func__, tag, offset);
1185                         goto exit;
1186                 }
1187
1188                 offset += len;
1189         }
1190
1191 exit:
1192         return err;
1193 }
1194
1195 static netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
1196 {
1197         int err = -1;
1198
1199         pr_debug("package xmit\n");
1200
1201         skb->dev = lowpan_dev_info(dev)->real_dev;
1202         if (skb->dev == NULL) {
1203                 pr_debug("ERROR: no real wpan device found\n");
1204                 goto error;
1205         }
1206
1207         /* Send directly if less than the MTU minus the 2 checksum bytes. */
1208         if (skb->len <= IEEE802154_MTU - IEEE802154_MFR_SIZE) {
1209                 err = dev_queue_xmit(skb);
1210                 goto out;
1211         }
1212
1213         pr_debug("frame is too big, fragmentation is needed\n");
1214         err = lowpan_skb_fragmentation(skb, dev);
1215 error:
1216         dev_kfree_skb(skb);
1217 out:
1218         if (err)
1219                 pr_debug("ERROR: xmit failed\n");
1220
1221         return (err < 0) ? NET_XMIT_DROP : err;
1222 }
1223
1224 static struct wpan_phy *lowpan_get_phy(const struct net_device *dev)
1225 {
1226         struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
1227         return ieee802154_mlme_ops(real_dev)->get_phy(real_dev);
1228 }
1229
1230 static u16 lowpan_get_pan_id(const struct net_device *dev)
1231 {
1232         struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
1233         return ieee802154_mlme_ops(real_dev)->get_pan_id(real_dev);
1234 }
1235
1236 static u16 lowpan_get_short_addr(const struct net_device *dev)
1237 {
1238         struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
1239         return ieee802154_mlme_ops(real_dev)->get_short_addr(real_dev);
1240 }
1241
1242 static u8 lowpan_get_dsn(const struct net_device *dev)
1243 {
1244         struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
1245         return ieee802154_mlme_ops(real_dev)->get_dsn(real_dev);
1246 }
1247
1248 static struct header_ops lowpan_header_ops = {
1249         .create = lowpan_header_create,
1250 };
1251
1252 static const struct net_device_ops lowpan_netdev_ops = {
1253         .ndo_start_xmit         = lowpan_xmit,
1254         .ndo_set_mac_address    = lowpan_set_address,
1255 };
1256
1257 static struct ieee802154_mlme_ops lowpan_mlme = {
1258         .get_pan_id = lowpan_get_pan_id,
1259         .get_phy = lowpan_get_phy,
1260         .get_short_addr = lowpan_get_short_addr,
1261         .get_dsn = lowpan_get_dsn,
1262 };
1263
1264 static void lowpan_setup(struct net_device *dev)
1265 {
1266         dev->addr_len           = IEEE802154_ADDR_LEN;
1267         memset(dev->broadcast, 0xff, IEEE802154_ADDR_LEN);
1268         dev->type               = ARPHRD_IEEE802154;
1269         /* Frame Control + Sequence Number + Address fields + Security Header */
1270         dev->hard_header_len    = 2 + 1 + 20 + 14;
1271         dev->needed_tailroom    = 2; /* FCS */
1272         dev->mtu                = 1281;
1273         dev->tx_queue_len       = 0;
1274         dev->flags              = IFF_BROADCAST | IFF_MULTICAST;
1275         dev->watchdog_timeo     = 0;
1276
1277         dev->netdev_ops         = &lowpan_netdev_ops;
1278         dev->header_ops         = &lowpan_header_ops;
1279         dev->ml_priv            = &lowpan_mlme;
1280         dev->destructor         = free_netdev;
1281 }
1282
1283 static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[])
1284 {
1285         if (tb[IFLA_ADDRESS]) {
1286                 if (nla_len(tb[IFLA_ADDRESS]) != IEEE802154_ADDR_LEN)
1287                         return -EINVAL;
1288         }
1289         return 0;
1290 }
1291
1292 static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
1293         struct packet_type *pt, struct net_device *orig_dev)
1294 {
1295         struct sk_buff *local_skb;
1296
1297         if (!netif_running(dev))
1298                 goto drop;
1299
1300         if (dev->type != ARPHRD_IEEE802154)
1301                 goto drop;
1302
1303         /* check that it's our buffer */
1304         if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
1305                 /* Copy the packet so that the IPv6 header is
1306                  * properly aligned.
1307                  */
1308                 local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
1309                                             skb_tailroom(skb), GFP_ATOMIC);
1310                 if (!local_skb)
1311                         goto drop;
1312
1313                 local_skb->protocol = htons(ETH_P_IPV6);
1314                 local_skb->pkt_type = PACKET_HOST;
1315
1316                 /* Pull off the 1-byte of 6lowpan header. */
1317                 skb_pull(local_skb, 1);
1318
1319                 lowpan_give_skb_to_devices(local_skb);
1320
1321                 kfree_skb(local_skb);
1322                 kfree_skb(skb);
1323         } else {
1324                 switch (skb->data[0] & 0xe0) {
1325                 case LOWPAN_DISPATCH_IPHC:      /* ipv6 datagram */
1326                 case LOWPAN_DISPATCH_FRAG1:     /* first fragment header */
1327                 case LOWPAN_DISPATCH_FRAGN:     /* next fragments headers */
1328                         local_skb = skb_clone(skb, GFP_ATOMIC);
1329                         if (!local_skb)
1330                                 goto drop;
1331                         lowpan_process_data(local_skb);
1332
1333                         kfree_skb(skb);
1334                         break;
1335                 default:
1336                         break;
1337                 }
1338         }
1339
1340         return NET_RX_SUCCESS;
1341
1342 drop:
1343         kfree_skb(skb);
1344         return NET_RX_DROP;
1345 }
1346
1347 static int lowpan_newlink(struct net *src_net, struct net_device *dev,
1348                           struct nlattr *tb[], struct nlattr *data[])
1349 {
1350         struct net_device *real_dev;
1351         struct lowpan_dev_record *entry;
1352
1353         pr_debug("adding new link\n");
1354
1355         if (!tb[IFLA_LINK])
1356                 return -EINVAL;
1357         /* find and hold real wpan device */
1358         real_dev = dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
1359         if (!real_dev)
1360                 return -ENODEV;
1361         if (real_dev->type != ARPHRD_IEEE802154) {
1362                 dev_put(real_dev);
1363                 return -EINVAL;
1364         }
1365
1366         lowpan_dev_info(dev)->real_dev = real_dev;
1367         lowpan_dev_info(dev)->fragment_tag = 0;
1368         mutex_init(&lowpan_dev_info(dev)->dev_list_mtx);
1369
1370         entry = kzalloc(sizeof(struct lowpan_dev_record), GFP_KERNEL);
1371         if (!entry) {
1372                 dev_put(real_dev);
1373                 lowpan_dev_info(dev)->real_dev = NULL;
1374                 return -ENOMEM;
1375         }
1376
1377         entry->ldev = dev;
1378
1379         /* Set the lowpan harware address to the wpan hardware address. */
1380         memcpy(dev->dev_addr, real_dev->dev_addr, IEEE802154_ADDR_LEN);
1381
1382         mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
1383         INIT_LIST_HEAD(&entry->list);
1384         list_add_tail(&entry->list, &lowpan_devices);
1385         mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);
1386
1387         register_netdevice(dev);
1388
1389         return 0;
1390 }
1391
1392 static void lowpan_dellink(struct net_device *dev, struct list_head *head)
1393 {
1394         struct lowpan_dev_info *lowpan_dev = lowpan_dev_info(dev);
1395         struct net_device *real_dev = lowpan_dev->real_dev;
1396         struct lowpan_dev_record *entry, *tmp;
1397
1398         ASSERT_RTNL();
1399
1400         mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
1401         list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
1402                 if (entry->ldev == dev) {
1403                         list_del(&entry->list);
1404                         kfree(entry);
1405                 }
1406         }
1407         mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);
1408
1409         mutex_destroy(&lowpan_dev_info(dev)->dev_list_mtx);
1410
1411         unregister_netdevice_queue(dev, head);
1412
1413         dev_put(real_dev);
1414 }
1415
1416 static struct rtnl_link_ops lowpan_link_ops __read_mostly = {
1417         .kind           = "lowpan",
1418         .priv_size      = sizeof(struct lowpan_dev_info),
1419         .setup          = lowpan_setup,
1420         .newlink        = lowpan_newlink,
1421         .dellink        = lowpan_dellink,
1422         .validate       = lowpan_validate,
1423 };
1424
1425 static inline int __init lowpan_netlink_init(void)
1426 {
1427         return rtnl_link_register(&lowpan_link_ops);
1428 }
1429
1430 static inline void lowpan_netlink_fini(void)
1431 {
1432         rtnl_link_unregister(&lowpan_link_ops);
1433 }
1434
1435 static int lowpan_device_event(struct notifier_block *unused,
1436                                unsigned long event, void *ptr)
1437 {
1438         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1439         LIST_HEAD(del_list);
1440         struct lowpan_dev_record *entry, *tmp;
1441
1442         if (dev->type != ARPHRD_IEEE802154)
1443                 goto out;
1444
1445         if (event == NETDEV_UNREGISTER) {
1446                 list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
1447                         if (lowpan_dev_info(entry->ldev)->real_dev == dev)
1448                                 lowpan_dellink(entry->ldev, &del_list);
1449                 }
1450
1451                 unregister_netdevice_many(&del_list);
1452         }
1453
1454 out:
1455         return NOTIFY_DONE;
1456 }
1457
1458 static struct notifier_block lowpan_dev_notifier = {
1459         .notifier_call = lowpan_device_event,
1460 };
1461
1462 static struct packet_type lowpan_packet_type = {
1463         .type = __constant_htons(ETH_P_IEEE802154),
1464         .func = lowpan_rcv,
1465 };
1466
1467 static int __init lowpan_init_module(void)
1468 {
1469         int err = 0;
1470
1471         err = lowpan_netlink_init();
1472         if (err < 0)
1473                 goto out;
1474
1475         dev_add_pack(&lowpan_packet_type);
1476
1477         err = register_netdevice_notifier(&lowpan_dev_notifier);
1478         if (err < 0) {
1479                 dev_remove_pack(&lowpan_packet_type);
1480                 lowpan_netlink_fini();
1481         }
1482 out:
1483         return err;
1484 }
1485
1486 static void __exit lowpan_cleanup_module(void)
1487 {
1488         struct lowpan_fragment *frame, *tframe;
1489
1490         lowpan_netlink_fini();
1491
1492         dev_remove_pack(&lowpan_packet_type);
1493
1494         unregister_netdevice_notifier(&lowpan_dev_notifier);
1495
1496         /* Now 6lowpan packet_type is removed, so no new fragments are
1497          * expected on RX, therefore that's the time to clean incomplete
1498          * fragments.
1499          */
1500         spin_lock_bh(&flist_lock);
1501         list_for_each_entry_safe(frame, tframe, &lowpan_fragments, list) {
1502                 del_timer_sync(&frame->timer);
1503                 list_del(&frame->list);
1504                 dev_kfree_skb(frame->skb);
1505                 kfree(frame);
1506         }
1507         spin_unlock_bh(&flist_lock);
1508 }
1509
1510 module_init(lowpan_init_module);
1511 module_exit(lowpan_cleanup_module);
1512 MODULE_LICENSE("GPL");
1513 MODULE_ALIAS_RTNL_LINK("lowpan");