net/ieee802154/6lowpan_iphc.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/netdevice.h>
  57 #include <net/ipv6.h>
  58 #include <net/af_ieee802154.h>
  59
  60 #include "6lowpan.h"
  61
  62 /*
  63  * Uncompress address function for source and
  64  * destination address(non-multicast).
  65  *
  66  * address_mode is sam value or dam value.
  67  */
  68 static int uncompress_addr(struct sk_buff *skb,
  69                                 struct in6_addr *ipaddr, const u8 address_mode,
  70                                 const u8 *lladdr, const u8 addr_type,
  71                                 const u8 addr_len)
  72 {
  73         bool fail;
  74
  75         switch (address_mode) {
  76         case LOWPAN_IPHC_ADDR_00:
  77                 /* for global link addresses */
  78                 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
  79                 break;
  80         case LOWPAN_IPHC_ADDR_01:
  81                 /* fe:80::XXXX:XXXX:XXXX:XXXX */
  82                 ipaddr->s6_addr[0] = 0xFE;
  83                 ipaddr->s6_addr[1] = 0x80;
  84                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
  85                 break;
  86         case LOWPAN_IPHC_ADDR_02:
  87                 /* fe:80::ff:fe00:XXXX */
  88                 ipaddr->s6_addr[0] = 0xFE;
  89                 ipaddr->s6_addr[1] = 0x80;
  90                 ipaddr->s6_addr[11] = 0xFF;
  91                 ipaddr->s6_addr[12] = 0xFE;
  92                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
  93                 break;
  94         case LOWPAN_IPHC_ADDR_03:
  95                 fail = false;
  96                 switch (addr_type) {
  97                 case IEEE802154_ADDR_LONG:
  98                         /* fe:80::XXXX:XXXX:XXXX:XXXX
  99                          *        \_________________/
 100                          *              hwaddr
 101                          */
 102                         ipaddr->s6_addr[0] = 0xFE;
 103                         ipaddr->s6_addr[1] = 0x80;
 104                         memcpy(&ipaddr->s6_addr[8], lladdr, addr_len);
 105                         /* second bit-flip (Universe/Local)
 106                          * is done according RFC2464
 107                          */
 108                         ipaddr->s6_addr[8] ^= 0x02;
 109                         break;
 110                 case IEEE802154_ADDR_SHORT:
 111                         /* fe:80::ff:fe00:XXXX
 112                          *                \__/
 113                          *             short_addr
 114                          *
 115                          * Universe/Local bit is zero.
 116                          */
 117                         ipaddr->s6_addr[0] = 0xFE;
 118                         ipaddr->s6_addr[1] = 0x80;
 119                         ipaddr->s6_addr[11] = 0xFF;
 120                         ipaddr->s6_addr[12] = 0xFE;
 121                         ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr));
 122                         break;
 123                 default:
 124                         pr_debug("Invalid addr_type set\n");
 125                         return -EINVAL;
 126                 }
 127                 break;
 128         default:
 129                 pr_debug("Invalid address mode value: 0x%x\n", address_mode);
 130                 return -EINVAL;
 131         }
 132
 133         if (fail) {
 134                 pr_debug("Failed to fetch skb data\n");
 135                 return -EIO;
 136         }
 137
 138         raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
 139                         ipaddr->s6_addr, 16);
 140
 141         return 0;
 142 }
 143
 144 /*
 145  * Uncompress address function for source context
 146  * based address(non-multicast).
 147  */
 148 static int uncompress_context_based_src_addr(struct sk_buff *skb,
 149                                                 struct in6_addr *ipaddr,
 150                                                 const u8 sam)
 151 {
 152         switch (sam) {
 153         case LOWPAN_IPHC_ADDR_00:
 154                 /* unspec address ::
 155                  * Do nothing, address is already ::
 156                  */
 157                 break;
 158         case LOWPAN_IPHC_ADDR_01:
 159                 /* TODO */
 160         case LOWPAN_IPHC_ADDR_02:
 161                 /* TODO */
 162         case LOWPAN_IPHC_ADDR_03:
 163                 /* TODO */
 164                 netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
 165                 return -EINVAL;
 166         default:
 167                 pr_debug("Invalid sam value: 0x%x\n", sam);
 168                 return -EINVAL;
 169         }
 170
 171         raw_dump_inline(NULL,
 172                         "Reconstructed context based ipv6 src addr is",
 173                         ipaddr->s6_addr, 16);
 174
 175         return 0;
 176 }
 177
 178 static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
 179                 struct net_device *dev, skb_delivery_cb deliver_skb)
 180 {
 181         struct sk_buff *new;
 182         int stat;
 183
 184         new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
 185                                                                 GFP_ATOMIC);
 186         kfree_skb(skb);
 187
 188         if (!new)
 189                 return -ENOMEM;
 190
 191         skb_push(new, sizeof(struct ipv6hdr));
 192         skb_reset_network_header(new);
 193         skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
 194
 195         new->protocol = htons(ETH_P_IPV6);
 196         new->pkt_type = PACKET_HOST;
 197         new->dev = dev;
 198
 199         raw_dump_table(__func__, "raw skb data dump before receiving",
 200                         new->data, new->len);
 201
 202         stat = deliver_skb(new, dev);
 203
 204         kfree_skb(new);
 205
 206         return stat;
 207 }
 208
 209 /* Uncompress function for multicast destination address,
 210  * when M bit is set.
 211  */
 212 static int
 213 lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 214                 struct in6_addr *ipaddr,
 215                 const u8 dam)
 216 {
 217         bool fail;
 218
 219         switch (dam) {
 220         case LOWPAN_IPHC_DAM_00:
 221                 /* 00:  128 bits.  The full address
 222                  * is carried in-line.
 223                  */
 224                 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
 225                 break;
 226         case LOWPAN_IPHC_DAM_01:
 227                 /* 01:  48 bits.  The address takes
 228                  * the form ffXX::00XX:XXXX:XXXX.
 229                  */
 230                 ipaddr->s6_addr[0] = 0xFF;
 231                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
 232                 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
 233                 break;
 234         case LOWPAN_IPHC_DAM_10:
 235                 /* 10:  32 bits.  The address takes
 236                  * the form ffXX::00XX:XXXX.
 237                  */
 238                 ipaddr->s6_addr[0] = 0xFF;
 239                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
 240                 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
 241                 break;
 242         case LOWPAN_IPHC_DAM_11:
 243                 /* 11:  8 bits.  The address takes
 244                  * the form ff02::00XX.
 245                  */
 246                 ipaddr->s6_addr[0] = 0xFF;
 247                 ipaddr->s6_addr[1] = 0x02;
 248                 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
 249                 break;
 250         default:
 251                 pr_debug("DAM value has a wrong value: 0x%x\n", dam);
 252                 return -EINVAL;
 253         }
 254
 255         if (fail) {
 256                 pr_debug("Failed to fetch skb data\n");
 257                 return -EIO;
 258         }
 259
 260         raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
 261                                 ipaddr->s6_addr, 16);
 262
 263         return 0;
 264 }
 265
 266 static int
 267 uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
 268 {
 269         bool fail;
 270         u8 tmp = 0, val = 0;
 271
 272         if (!uh)
 273                 goto err;
 274
 275         fail = lowpan_fetch_skb(skb, &tmp, 1);
 276
 277         if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
 278                 pr_debug("UDP header uncompression\n");
 279                 switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
 280                 case LOWPAN_NHC_UDP_CS_P_00:
 281                         fail |= lowpan_fetch_skb(skb, &uh->source, 2);
 282                         fail |= lowpan_fetch_skb(skb, &uh->dest, 2);
 283                         break;
 284                 case LOWPAN_NHC_UDP_CS_P_01:
 285                         fail |= lowpan_fetch_skb(skb, &uh->source, 2);
 286                         fail |= lowpan_fetch_skb(skb, &val, 1);
 287                         uh->dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
 288                         break;
 289                 case LOWPAN_NHC_UDP_CS_P_10:
 290                         fail |= lowpan_fetch_skb(skb, &val, 1);
 291                         uh->source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
 292                         fail |= lowpan_fetch_skb(skb, &uh->dest, 2);
 293                         break;
 294                 case LOWPAN_NHC_UDP_CS_P_11:
 295                         fail |= lowpan_fetch_skb(skb, &val, 1);
 296                         uh->source = htons(LOWPAN_NHC_UDP_4BIT_PORT +
 297                                            (val >> 4));
 298                         uh->dest = htons(LOWPAN_NHC_UDP_4BIT_PORT +
 299                                          (val & 0x0f));
 300                         break;
 301                 default:
 302                         pr_debug("ERROR: unknown UDP format\n");
 303                         goto err;
 304                         break;
 305                 }
 306
 307                 pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
 308                          ntohs(uh->source), ntohs(uh->dest));
 309
 310                 /* checksum */
 311                 if (tmp & LOWPAN_NHC_UDP_CS_C) {
 312                         pr_debug_ratelimited("checksum elided currently not supported\n");
 313                         goto err;
 314                 } else {
 315                         fail |= lowpan_fetch_skb(skb, &uh->check, 2);
 316                 }
 317
 318                 /*
 319                  * UDP lenght needs to be infered from the lower layers
 320                  * here, we obtain the hint from the remaining size of the
 321                  * frame
 322                  */
 323                 uh->len = htons(skb->len + sizeof(struct udphdr));
 324                 pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len));
 325         } else {
 326                 pr_debug("ERROR: unsupported NH format\n");
 327                 goto err;
 328         }
 329
 330         if (fail)
 331                 goto err;
 332
 333         return 0;
 334 err:
 335         return -EINVAL;
 336 }
 337
 338 /* TTL uncompression values */
 339 static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
 340
 341 int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
 342                 const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
 343                 const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
 344                 u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
 345 {
 346         struct ipv6hdr hdr = {};
 347         u8 tmp, num_context = 0;
 348         int err;
 349
 350         raw_dump_table(__func__, "raw skb data dump uncompressed",
 351                                 skb->data, skb->len);
 352
 353         /* another if the CID flag is set */
 354         if (iphc1 & LOWPAN_IPHC_CID) {
 355                 pr_debug("CID flag is set, increase header with one\n");
 356                 if (lowpan_fetch_skb_u8(skb, &num_context))
 357                         goto drop;
 358         }
 359
 360         hdr.version = 6;
 361
 362         /* Traffic Class and Flow Label */
 363         switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
 364         /*
 365          * Traffic Class and FLow Label carried in-line
 366          * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
 367          */
 368         case 0: /* 00b */
 369                 if (lowpan_fetch_skb_u8(skb, &tmp))
 370                         goto drop;
 371
 372                 memcpy(&hdr.flow_lbl, &skb->data[0], 3);
 373                 skb_pull(skb, 3);
 374                 hdr.priority = ((tmp >> 2) & 0x0f);
 375                 hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
 376                                         (hdr.flow_lbl[0] & 0x0f);
 377                 break;
 378         /*
 379          * Traffic class carried in-line
 380          * ECN + DSCP (1 byte), Flow Label is elided
 381          */
 382         case 2: /* 10b */
 383                 if (lowpan_fetch_skb_u8(skb, &tmp))
 384                         goto drop;
 385
 386                 hdr.priority = ((tmp >> 2) & 0x0f);
 387                 hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
 388                 break;
 389         /*
 390          * Flow Label carried in-line
 391          * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
 392          */
 393         case 1: /* 01b */
 394                 if (lowpan_fetch_skb_u8(skb, &tmp))
 395                         goto drop;
 396
 397                 hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
 398                 memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
 399                 skb_pull(skb, 2);
 400                 break;
 401         /* Traffic Class and Flow Label are elided */
 402         case 3: /* 11b */
 403                 break;
 404         default:
 405                 break;
 406         }
 407
 408         /* Next Header */
 409         if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
 410                 /* Next header is carried inline */
 411                 if (lowpan_fetch_skb_u8(skb, &(hdr.nexthdr)))
 412                         goto drop;
 413
 414                 pr_debug("NH flag is set, next header carried inline: %02x\n",
 415                          hdr.nexthdr);
 416         }
 417
 418         /* Hop Limit */
 419         if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I)
 420                 hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
 421         else {
 422                 if (lowpan_fetch_skb_u8(skb, &(hdr.hop_limit)))
 423                         goto drop;
 424         }
 425
 426         /* Extract SAM to the tmp variable */
 427         tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
 428
 429         if (iphc1 & LOWPAN_IPHC_SAC) {
 430                 /* Source address context based uncompression */
 431                 pr_debug("SAC bit is set. Handle context based source address.\n");
 432                 err = uncompress_context_based_src_addr(
 433                                 skb, &hdr.saddr, tmp);
 434         } else {
 435                 /* Source address uncompression */
 436                 pr_debug("source address stateless compression\n");
 437                 err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
 438                                         saddr_type, saddr_len);
 439         }
 440
 441         /* Check on error of previous branch */
 442         if (err)
 443                 goto drop;
 444
 445         /* Extract DAM to the tmp variable */
 446         tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
 447
 448         /* check for Multicast Compression */
 449         if (iphc1 & LOWPAN_IPHC_M) {
 450                 if (iphc1 & LOWPAN_IPHC_DAC) {
 451                         pr_debug("dest: context-based mcast compression\n");
 452                         /* TODO: implement this */
 453                 } else {
 454                         err = lowpan_uncompress_multicast_daddr(
 455                                                 skb, &hdr.daddr, tmp);
 456                         if (err)
 457                                 goto drop;
 458                 }
 459         } else {
 460                 err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
 461                                         daddr_type, daddr_len);
 462                 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
 463                         tmp, &hdr.daddr);
 464                 if (err)
 465                         goto drop;
 466         }
 467
 468         /* UDP data uncompression */
 469         if (iphc0 & LOWPAN_IPHC_NH_C) {
 470                 struct udphdr uh;
 471                 struct sk_buff *new;
 472                 if (uncompress_udp_header(skb, &uh))
 473                         goto drop;
 474
 475                 /*
 476                  * replace the compressed UDP head by the uncompressed UDP
 477                  * header
 478                  */
 479                 new = skb_copy_expand(skb, sizeof(struct udphdr),
 480                                       skb_tailroom(skb), GFP_ATOMIC);
 481                 kfree_skb(skb);
 482
 483                 if (!new)
 484                         return -ENOMEM;
 485
 486                 skb = new;
 487
 488                 skb_push(skb, sizeof(struct udphdr));
 489                 skb_reset_transport_header(skb);
 490                 skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));
 491
 492                 raw_dump_table(__func__, "raw UDP header dump",
 493                                       (u8 *)&uh, sizeof(uh));
 494
 495                 hdr.nexthdr = UIP_PROTO_UDP;
 496         }
 497
 498         hdr.payload_len = htons(skb->len);
 499
 500         pr_debug("skb headroom size = %d, data length = %d\n",
 501                  skb_headroom(skb), skb->len);
 502
 503         pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength  = %d\n\t"
 504                  "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest    = %pI6c\n",
 505                 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
 506                 hdr.hop_limit, &hdr.daddr);
 507
 508         raw_dump_table(__func__, "raw header dump", (u8 *)&hdr,
 509                                                         sizeof(hdr));
 510
 511         return skb_deliver(skb, &hdr, dev, deliver_skb);
 512
 513 drop:
 514         kfree_skb(skb);
 515         return -EINVAL;
 516 }
 517 EXPORT_SYMBOL_GPL(lowpan_process_data);
 518
 519 static u8 lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift,
 520                                 const struct in6_addr *ipaddr,
 521                                 const unsigned char *lladdr)
 522 {
 523         u8 val = 0;
 524
 525         if (is_addr_mac_addr_based(ipaddr, lladdr)) {
 526                 val = 3; /* 0-bits */
 527                 pr_debug("address compression 0 bits\n");
 528         } else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
 529                 /* compress IID to 16 bits xxxx::XXXX */
 530                 memcpy(*hc06_ptr, &ipaddr->s6_addr16[7], 2);
 531                 *hc06_ptr += 2;
 532                 val = 2; /* 16-bits */
 533                 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
 534                         *hc06_ptr - 2, 2);
 535         } else {
 536                 /* do not compress IID => xxxx::IID */
 537                 memcpy(*hc06_ptr, &ipaddr->s6_addr16[4], 8);
 538                 *hc06_ptr += 8;
 539                 val = 1; /* 64-bits */
 540                 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
 541                         *hc06_ptr - 8, 8);
 542         }
 543
 544         return rol8(val, shift);
 545 }
 546
 547 static void compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb)
 548 {
 549         struct udphdr *uh = udp_hdr(skb);
 550         u8 tmp;
 551
 552         if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) ==
 553              LOWPAN_NHC_UDP_4BIT_PORT) &&
 554             ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) ==
 555              LOWPAN_NHC_UDP_4BIT_PORT)) {
 556                 pr_debug("UDP header: both ports compression to 4 bits\n");
 557                 /* compression value */
 558                 tmp = LOWPAN_NHC_UDP_CS_P_11;
 559                 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
 560                 /* source and destination port */
 561                 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT +
 562                       ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4);
 563                 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
 564         } else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) ==
 565                         LOWPAN_NHC_UDP_8BIT_PORT) {
 566                 pr_debug("UDP header: remove 8 bits of dest\n");
 567                 /* compression value */
 568                 tmp = LOWPAN_NHC_UDP_CS_P_01;
 569                 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
 570                 /* source port */
 571                 lowpan_push_hc_data(hc06_ptr, &uh->source, sizeof(uh->source));
 572                 /* destination port */
 573                 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT;
 574                 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
 575         } else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) ==
 576                         LOWPAN_NHC_UDP_8BIT_PORT) {
 577                 pr_debug("UDP header: remove 8 bits of source\n");
 578                 /* compression value */
 579                 tmp = LOWPAN_NHC_UDP_CS_P_10;
 580                 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
 581                 /* source port */
 582                 tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT;
 583                 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
 584                 /* destination port */
 585                 lowpan_push_hc_data(hc06_ptr, &uh->dest, sizeof(uh->dest));
 586         } else {
 587                 pr_debug("UDP header: can't compress\n");
 588                 /* compression value */
 589                 tmp = LOWPAN_NHC_UDP_CS_P_00;
 590                 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
 591                 /* source port */
 592                 lowpan_push_hc_data(hc06_ptr, &uh->source, sizeof(uh->source));
 593                 /* destination port */
 594                 lowpan_push_hc_data(hc06_ptr, &uh->dest, sizeof(uh->dest));
 595         }
 596
 597         /* checksum is always inline */
 598         lowpan_push_hc_data(hc06_ptr, &uh->check, sizeof(uh->check));
 599
 600         /* skip the UDP header */
 601         skb_pull(skb, sizeof(struct udphdr));
 602 }
 603
 604 int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
 605                         unsigned short type, const void *_daddr,
 606                         const void *_saddr, unsigned int len)
 607 {
 608         u8 tmp, iphc0, iphc1, *hc06_ptr;
 609         struct ipv6hdr *hdr;
 610         u8 head[100] = {};
 611
 612         if (type != ETH_P_IPV6)
 613                 return -EINVAL;
 614
 615         hdr = ipv6_hdr(skb);
 616         hc06_ptr = head + 2;
 617
 618         pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength  = %d\n"
 619                  "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest    = %pI6c\n",
 620                 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
 621                 hdr->hop_limit, &hdr->daddr);
 622
 623         raw_dump_table(__func__, "raw skb network header dump",
 624                 skb_network_header(skb), sizeof(struct ipv6hdr));
 625
 626         /*
 627          * As we copy some bit-length fields, in the IPHC encoding bytes,
 628          * we sometimes use |=
 629          * If the field is 0, and the current bit value in memory is 1,
 630          * this does not work. We therefore reset the IPHC encoding here
 631          */
 632         iphc0 = LOWPAN_DISPATCH_IPHC;
 633         iphc1 = 0;
 634
 635         /* TODO: context lookup */
 636
 637         raw_dump_inline(__func__, "saddr",
 638                         (unsigned char *)_saddr, IEEE802154_ADDR_LEN);
 639         raw_dump_inline(__func__, "daddr",
 640                         (unsigned char *)_daddr, IEEE802154_ADDR_LEN);
 641
 642         raw_dump_table(__func__,
 643                         "sending raw skb network uncompressed packet",
 644                         skb->data, skb->len);
 645
 646         /*
 647          * Traffic class, flow label
 648          * If flow label is 0, compress it. If traffic class is 0, compress it
 649          * We have to process both in the same time as the offset of traffic
 650          * class depends on the presence of version and flow label
 651          */
 652
 653         /* hc06 format of TC is ECN | DSCP , original one is DSCP | ECN */
 654         tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
 655         tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
 656
 657         if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
 658              (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
 659                 /* flow label can be compressed */
 660                 iphc0 |= LOWPAN_IPHC_FL_C;
 661                 if ((hdr->priority == 0) &&
 662                    ((hdr->flow_lbl[0] & 0xF0) == 0)) {
 663                         /* compress (elide) all */
 664                         iphc0 |= LOWPAN_IPHC_TC_C;
 665                 } else {
 666                         /* compress only the flow label */
 667                         *hc06_ptr = tmp;
 668                         hc06_ptr += 1;
 669                 }
 670         } else {
 671                 /* Flow label cannot be compressed */
 672                 if ((hdr->priority == 0) &&
 673                    ((hdr->flow_lbl[0] & 0xF0) == 0)) {
 674                         /* compress only traffic class */
 675                         iphc0 |= LOWPAN_IPHC_TC_C;
 676                         *hc06_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
 677                         memcpy(hc06_ptr + 1, &hdr->flow_lbl[1], 2);
 678                         hc06_ptr += 3;
 679                 } else {
 680                         /* compress nothing */
 681                         memcpy(hc06_ptr, hdr, 4);
 682                         /* replace the top byte with new ECN | DSCP format */
 683                         *hc06_ptr = tmp;
 684                         hc06_ptr += 4;
 685                 }
 686         }
 687
 688         /* NOTE: payload length is always compressed */
 689
 690         /* Next Header is compress if UDP */
 691         if (hdr->nexthdr == UIP_PROTO_UDP)
 692                 iphc0 |= LOWPAN_IPHC_NH_C;
 693
 694         if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
 695                 *hc06_ptr = hdr->nexthdr;
 696                 hc06_ptr += 1;
 697         }
 698
 699         /*
 700          * Hop limit
 701          * if 1:   compress, encoding is 01
 702          * if 64:  compress, encoding is 10
 703          * if 255: compress, encoding is 11
 704          * else do not compress
 705          */
 706         switch (hdr->hop_limit) {
 707         case 1:
 708                 iphc0 |= LOWPAN_IPHC_TTL_1;
 709                 break;
 710         case 64:
 711                 iphc0 |= LOWPAN_IPHC_TTL_64;
 712                 break;
 713         case 255:
 714                 iphc0 |= LOWPAN_IPHC_TTL_255;
 715                 break;
 716         default:
 717                 *hc06_ptr = hdr->hop_limit;
 718                 hc06_ptr += 1;
 719                 break;
 720         }
 721
 722         /* source address compression */
 723         if (is_addr_unspecified(&hdr->saddr)) {
 724                 pr_debug("source address is unspecified, setting SAC\n");
 725                 iphc1 |= LOWPAN_IPHC_SAC;
 726         /* TODO: context lookup */
 727         } else if (is_addr_link_local(&hdr->saddr)) {
 728                 iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
 729                                 LOWPAN_IPHC_SAM_BIT, &hdr->saddr, _saddr);
 730                 pr_debug("source address unicast link-local %pI6c "
 731                         "iphc1 0x%02x\n", &hdr->saddr, iphc1);
 732         } else {
 733                 pr_debug("send the full source address\n");
 734                 memcpy(hc06_ptr, &hdr->saddr.s6_addr16[0], 16);
 735                 hc06_ptr += 16;
 736         }
 737
 738         /* destination address compression */
 739         if (is_addr_mcast(&hdr->daddr)) {
 740                 pr_debug("destination address is multicast: ");
 741                 iphc1 |= LOWPAN_IPHC_M;
 742                 if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
 743                         pr_debug("compressed to 1 octet\n");
 744                         iphc1 |= LOWPAN_IPHC_DAM_11;
 745                         /* use last byte */
 746                         *hc06_ptr = hdr->daddr.s6_addr[15];
 747                         hc06_ptr += 1;
 748                 } else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
 749                         pr_debug("compressed to 4 octets\n");
 750                         iphc1 |= LOWPAN_IPHC_DAM_10;
 751                         /* second byte + the last three */
 752                         *hc06_ptr = hdr->daddr.s6_addr[1];
 753                         memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[13], 3);
 754                         hc06_ptr += 4;
 755                 } else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
 756                         pr_debug("compressed to 6 octets\n");
 757                         iphc1 |= LOWPAN_IPHC_DAM_01;
 758                         /* second byte + the last five */
 759                         *hc06_ptr = hdr->daddr.s6_addr[1];
 760                         memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[11], 5);
 761                         hc06_ptr += 6;
 762                 } else {
 763                         pr_debug("using full address\n");
 764                         iphc1 |= LOWPAN_IPHC_DAM_00;
 765                         memcpy(hc06_ptr, &hdr->daddr.s6_addr[0], 16);
 766                         hc06_ptr += 16;
 767                 }
 768         } else {
 769                 /* TODO: context lookup */
 770                 if (is_addr_link_local(&hdr->daddr)) {
 771                         iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
 772                                 LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr);
 773                         pr_debug("dest address unicast link-local %pI6c "
 774                                 "iphc1 0x%02x\n", &hdr->daddr, iphc1);
 775                 } else {
 776                         pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
 777                         memcpy(hc06_ptr, &hdr->daddr.s6_addr16[0], 16);
 778                         hc06_ptr += 16;
 779                 }
 780         }
 781
 782         /* UDP header compression */
 783         if (hdr->nexthdr == UIP_PROTO_UDP)
 784                 compress_udp_header(&hc06_ptr, skb);
 785
 786         head[0] = iphc0;
 787         head[1] = iphc1;
 788
 789         skb_pull(skb, sizeof(struct ipv6hdr));
 790         skb_reset_transport_header(skb);
 791         memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head);
 792         skb_reset_network_header(skb);
 793
 794         pr_debug("header len %d skb %u\n", (int)(hc06_ptr - head), skb->len);
 795
 796         raw_dump_table(__func__, "raw skb data dump compressed",
 797                                 skb->data, skb->len);
 798         return 0;
 799 }
 800 EXPORT_SYMBOL_GPL(lowpan_header_compress);
 801
 802 MODULE_LICENSE("GPL");