1 /* 2 * Copyright 2011, Siemens AG 3 * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com> 4 */ 5 6 /* Based on patches from Jon Smirl <jonsmirl@gmail.com> 7 * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 11 * as published by the Free Software Foundation. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 */ 19 20 /* Jon's code is based on 6lowpan implementation for Contiki which is: 21 * Copyright (c) 2008, Swedish Institute of Computer Science. 22 * All rights reserved. 23 * 24 * Redistribution and use in source and binary forms, with or without 25 * modification, are permitted provided that the following conditions 26 * are met: 27 * 1. Redistributions of source code must retain the above copyright 28 * notice, this list of conditions and the following disclaimer. 29 * 2. Redistributions in binary form must reproduce the above copyright 30 * notice, this list of conditions and the following disclaimer in the 31 * documentation and/or other materials provided with the distribution. 32 * 3. Neither the name of the Institute nor the names of its contributors 33 * may be used to endorse or promote products derived from this software 34 * without specific prior written permission. 35 * 36 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 37 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 39 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 40 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 41 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 42 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 44 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 45 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 46 * SUCH DAMAGE. 47 */ 48 49 #include <linux/bitops.h> 50 #include <linux/if_arp.h> 51 #include <linux/module.h> 52 #include <linux/netdevice.h> 53 #include <net/6lowpan.h> 54 #include <net/ipv6.h> 55 #include <net/af_ieee802154.h> 56 57 /* Uncompress address function for source and 58 * destination address(non-multicast). 59 * 60 * address_mode is sam value or dam value. 61 */ 62 static int uncompress_addr(struct sk_buff *skb, 63 struct in6_addr *ipaddr, const u8 address_mode, 64 const u8 *lladdr, const u8 addr_type, 65 const u8 addr_len) 66 { 67 bool fail; 68 69 switch (address_mode) { 70 case LOWPAN_IPHC_ADDR_00: 71 /* for global link addresses */ 72 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16); 73 break; 74 case LOWPAN_IPHC_ADDR_01: 75 /* fe:80::XXXX:XXXX:XXXX:XXXX */ 76 ipaddr->s6_addr[0] = 0xFE; 77 ipaddr->s6_addr[1] = 0x80; 78 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8); 79 break; 80 case LOWPAN_IPHC_ADDR_02: 81 /* fe:80::ff:fe00:XXXX */ 82 ipaddr->s6_addr[0] = 0xFE; 83 ipaddr->s6_addr[1] = 0x80; 84 ipaddr->s6_addr[11] = 0xFF; 85 ipaddr->s6_addr[12] = 0xFE; 86 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2); 87 break; 88 case LOWPAN_IPHC_ADDR_03: 89 fail = false; 90 switch (addr_type) { 91 case IEEE802154_ADDR_LONG: 92 /* fe:80::XXXX:XXXX:XXXX:XXXX 93 * \_________________/ 94 * hwaddr 95 */ 96 ipaddr->s6_addr[0] = 0xFE; 97 ipaddr->s6_addr[1] = 0x80; 98 memcpy(&ipaddr->s6_addr[8], lladdr, addr_len); 99 /* second bit-flip (Universe/Local) 100 * is done according RFC2464 101 */ 102 ipaddr->s6_addr[8] ^= 0x02; 103 break; 104 case IEEE802154_ADDR_SHORT: 105 /* fe:80::ff:fe00:XXXX 106 * \__/ 107 * short_addr 108 * 109 * Universe/Local bit is zero. 110 */ 111 ipaddr->s6_addr[0] = 0xFE; 112 ipaddr->s6_addr[1] = 0x80; 113 ipaddr->s6_addr[11] = 0xFF; 114 ipaddr->s6_addr[12] = 0xFE; 115 ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr)); 116 break; 117 default: 118 pr_debug("Invalid addr_type set\n"); 119 return -EINVAL; 120 } 121 break; 122 default: 123 pr_debug("Invalid address mode value: 0x%x\n", address_mode); 124 return -EINVAL; 125 } 126 127 if (fail) { 128 pr_debug("Failed to fetch skb data\n"); 129 return -EIO; 130 } 131 132 raw_dump_inline(NULL, "Reconstructed ipv6 addr is", 133 ipaddr->s6_addr, 16); 134 135 return 0; 136 } 137 138 /* Uncompress address function for source context 139 * based address(non-multicast). 140 */ 141 static int uncompress_context_based_src_addr(struct sk_buff *skb, 142 struct in6_addr *ipaddr, 143 const u8 sam) 144 { 145 switch (sam) { 146 case LOWPAN_IPHC_ADDR_00: 147 /* unspec address :: 148 * Do nothing, address is already :: 149 */ 150 break; 151 case LOWPAN_IPHC_ADDR_01: 152 /* TODO */ 153 case LOWPAN_IPHC_ADDR_02: 154 /* TODO */ 155 case LOWPAN_IPHC_ADDR_03: 156 /* TODO */ 157 netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam); 158 return -EINVAL; 159 default: 160 pr_debug("Invalid sam value: 0x%x\n", sam); 161 return -EINVAL; 162 } 163 164 raw_dump_inline(NULL, 165 "Reconstructed context based ipv6 src addr is", 166 ipaddr->s6_addr, 16); 167 168 return 0; 169 } 170 171 /* Uncompress function for multicast destination address, 172 * when M bit is set. 173 */ 174 static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb, 175 struct in6_addr *ipaddr, 176 const u8 dam) 177 { 178 bool fail; 179 180 switch (dam) { 181 case LOWPAN_IPHC_DAM_00: 182 /* 00: 128 bits. The full address 183 * is carried in-line. 184 */ 185 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16); 186 break; 187 case LOWPAN_IPHC_DAM_01: 188 /* 01: 48 bits. The address takes 189 * the form ffXX::00XX:XXXX:XXXX. 190 */ 191 ipaddr->s6_addr[0] = 0xFF; 192 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1); 193 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5); 194 break; 195 case LOWPAN_IPHC_DAM_10: 196 /* 10: 32 bits. The address takes 197 * the form ffXX::00XX:XXXX. 198 */ 199 ipaddr->s6_addr[0] = 0xFF; 200 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1); 201 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3); 202 break; 203 case LOWPAN_IPHC_DAM_11: 204 /* 11: 8 bits. The address takes 205 * the form ff02::00XX. 206 */ 207 ipaddr->s6_addr[0] = 0xFF; 208 ipaddr->s6_addr[1] = 0x02; 209 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1); 210 break; 211 default: 212 pr_debug("DAM value has a wrong value: 0x%x\n", dam); 213 return -EINVAL; 214 } 215 216 if (fail) { 217 pr_debug("Failed to fetch skb data\n"); 218 return -EIO; 219 } 220 221 raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is", 222 ipaddr->s6_addr, 16); 223 224 return 0; 225 } 226 227 static int uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh) 228 { 229 bool fail; 230 u8 tmp = 0, val = 0; 231 232 fail = lowpan_fetch_skb(skb, &tmp, sizeof(tmp)); 233 234 if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) { 235 pr_debug("UDP header uncompression\n"); 236 switch (tmp & LOWPAN_NHC_UDP_CS_P_11) { 237 case LOWPAN_NHC_UDP_CS_P_00: 238 fail |= lowpan_fetch_skb(skb, &uh->source, 239 sizeof(uh->source)); 240 fail |= lowpan_fetch_skb(skb, &uh->dest, 241 sizeof(uh->dest)); 242 break; 243 case LOWPAN_NHC_UDP_CS_P_01: 244 fail |= lowpan_fetch_skb(skb, &uh->source, 245 sizeof(uh->source)); 246 fail |= lowpan_fetch_skb(skb, &val, sizeof(val)); 247 uh->dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT); 248 break; 249 case LOWPAN_NHC_UDP_CS_P_10: 250 fail |= lowpan_fetch_skb(skb, &val, sizeof(val)); 251 uh->source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT); 252 fail |= lowpan_fetch_skb(skb, &uh->dest, 253 sizeof(uh->dest)); 254 break; 255 case LOWPAN_NHC_UDP_CS_P_11: 256 fail |= lowpan_fetch_skb(skb, &val, sizeof(val)); 257 uh->source = htons(LOWPAN_NHC_UDP_4BIT_PORT + 258 (val >> 4)); 259 uh->dest = htons(LOWPAN_NHC_UDP_4BIT_PORT + 260 (val & 0x0f)); 261 break; 262 default: 263 pr_debug("ERROR: unknown UDP format\n"); 264 goto err; 265 } 266 267 pr_debug("uncompressed UDP ports: src = %d, dst = %d\n", 268 ntohs(uh->source), ntohs(uh->dest)); 269 270 /* checksum */ 271 if (tmp & LOWPAN_NHC_UDP_CS_C) { 272 pr_debug_ratelimited("checksum elided currently not supported\n"); 273 goto err; 274 } else { 275 fail |= lowpan_fetch_skb(skb, &uh->check, 276 sizeof(uh->check)); 277 } 278 279 /* UDP length needs to be infered from the lower layers 280 * here, we obtain the hint from the remaining size of the 281 * frame 282 */ 283 uh->len = htons(skb->len + sizeof(struct udphdr)); 284 pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len)); 285 } else { 286 pr_debug("ERROR: unsupported NH format\n"); 287 goto err; 288 } 289 290 if (fail) 291 goto err; 292 293 return 0; 294 err: 295 return -EINVAL; 296 } 297 298 /* TTL uncompression values */ 299 static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 }; 300 301 int 302 lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev, 303 const u8 *saddr, const u8 saddr_type, 304 const u8 saddr_len, const u8 *daddr, 305 const u8 daddr_type, const u8 daddr_len, 306 u8 iphc0, u8 iphc1) 307 { 308 struct ipv6hdr hdr = {}; 309 u8 tmp, num_context = 0; 310 int err; 311 312 raw_dump_table(__func__, "raw skb data dump uncompressed", 313 skb->data, skb->len); 314 315 /* another if the CID flag is set */ 316 if (iphc1 & LOWPAN_IPHC_CID) { 317 pr_debug("CID flag is set, increase header with one\n"); 318 if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context))) 319 return -EINVAL; 320 } 321 322 hdr.version = 6; 323 324 /* Traffic Class and Flow Label */ 325 switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) { 326 /* Traffic Class and FLow Label carried in-line 327 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) 328 */ 329 case 0: /* 00b */ 330 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) 331 return -EINVAL; 332 333 memcpy(&hdr.flow_lbl, &skb->data[0], 3); 334 skb_pull(skb, 3); 335 hdr.priority = ((tmp >> 2) & 0x0f); 336 hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) | 337 (hdr.flow_lbl[0] & 0x0f); 338 break; 339 /* Traffic class carried in-line 340 * ECN + DSCP (1 byte), Flow Label is elided 341 */ 342 case 2: /* 10b */ 343 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) 344 return -EINVAL; 345 346 hdr.priority = ((tmp >> 2) & 0x0f); 347 hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30); 348 break; 349 /* Flow Label carried in-line 350 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided 351 */ 352 case 1: /* 01b */ 353 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) 354 return -EINVAL; 355 356 hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30); 357 memcpy(&hdr.flow_lbl[1], &skb->data[0], 2); 358 skb_pull(skb, 2); 359 break; 360 /* Traffic Class and Flow Label are elided */ 361 case 3: /* 11b */ 362 break; 363 default: 364 break; 365 } 366 367 /* Next Header */ 368 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) { 369 /* Next header is carried inline */ 370 if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr))) 371 return -EINVAL; 372 373 pr_debug("NH flag is set, next header carried inline: %02x\n", 374 hdr.nexthdr); 375 } 376 377 /* Hop Limit */ 378 if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) { 379 hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03]; 380 } else { 381 if (lowpan_fetch_skb(skb, &hdr.hop_limit, 382 sizeof(hdr.hop_limit))) 383 return -EINVAL; 384 } 385 386 /* Extract SAM to the tmp variable */ 387 tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03; 388 389 if (iphc1 & LOWPAN_IPHC_SAC) { 390 /* Source address context based uncompression */ 391 pr_debug("SAC bit is set. Handle context based source address.\n"); 392 err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp); 393 } else { 394 /* Source address uncompression */ 395 pr_debug("source address stateless compression\n"); 396 err = uncompress_addr(skb, &hdr.saddr, tmp, saddr, 397 saddr_type, saddr_len); 398 } 399 400 /* Check on error of previous branch */ 401 if (err) 402 return -EINVAL; 403 404 /* Extract DAM to the tmp variable */ 405 tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03; 406 407 /* check for Multicast Compression */ 408 if (iphc1 & LOWPAN_IPHC_M) { 409 if (iphc1 & LOWPAN_IPHC_DAC) { 410 pr_debug("dest: context-based mcast compression\n"); 411 /* TODO: implement this */ 412 } else { 413 err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr, 414 tmp); 415 416 if (err) 417 return -EINVAL; 418 } 419 } else { 420 err = uncompress_addr(skb, &hdr.daddr, tmp, daddr, 421 daddr_type, daddr_len); 422 pr_debug("dest: stateless compression mode %d dest %pI6c\n", 423 tmp, &hdr.daddr); 424 if (err) 425 return -EINVAL; 426 } 427 428 /* UDP data uncompression */ 429 if (iphc0 & LOWPAN_IPHC_NH_C) { 430 struct udphdr uh; 431 const int needed = sizeof(struct udphdr) + sizeof(hdr); 432 433 if (uncompress_udp_header(skb, &uh)) 434 return -EINVAL; 435 436 /* replace the compressed UDP head by the uncompressed UDP 437 * header 438 */ 439 err = skb_cow(skb, needed); 440 if (unlikely(err)) 441 return err; 442 443 skb_push(skb, sizeof(struct udphdr)); 444 skb_reset_transport_header(skb); 445 skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr)); 446 447 raw_dump_table(__func__, "raw UDP header dump", 448 (u8 *)&uh, sizeof(uh)); 449 450 hdr.nexthdr = UIP_PROTO_UDP; 451 } else { 452 err = skb_cow(skb, sizeof(hdr)); 453 if (unlikely(err)) 454 return err; 455 } 456 457 hdr.payload_len = htons(skb->len); 458 459 pr_debug("skb headroom size = %d, data length = %d\n", 460 skb_headroom(skb), skb->len); 461 462 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t" 463 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n", 464 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr, 465 hdr.hop_limit, &hdr.daddr); 466 467 skb_push(skb, sizeof(hdr)); 468 skb_reset_network_header(skb); 469 skb_copy_to_linear_data(skb, &hdr, sizeof(hdr)); 470 471 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr)); 472 473 return 0; 474 } 475 EXPORT_SYMBOL_GPL(lowpan_header_decompress); 476 477 static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift, 478 const struct in6_addr *ipaddr, 479 const unsigned char *lladdr) 480 { 481 u8 val = 0; 482 483 if (is_addr_mac_addr_based(ipaddr, lladdr)) { 484 val = 3; /* 0-bits */ 485 pr_debug("address compression 0 bits\n"); 486 } else if (lowpan_is_iid_16_bit_compressable(ipaddr)) { 487 /* compress IID to 16 bits xxxx::XXXX */ 488 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2); 489 val = 2; /* 16-bits */ 490 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)", 491 *hc_ptr - 2, 2); 492 } else { 493 /* do not compress IID => xxxx::IID */ 494 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8); 495 val = 1; /* 64-bits */ 496 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)", 497 *hc_ptr - 8, 8); 498 } 499 500 return rol8(val, shift); 501 } 502 503 static void compress_udp_header(u8 **hc_ptr, struct sk_buff *skb) 504 { 505 struct udphdr *uh; 506 u8 tmp; 507 508 /* In the case of RAW sockets the transport header is not set by 509 * the ip6 stack so we must set it ourselves 510 */ 511 if (skb->transport_header == skb->network_header) 512 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 513 514 uh = udp_hdr(skb); 515 516 if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) == 517 LOWPAN_NHC_UDP_4BIT_PORT) && 518 ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) == 519 LOWPAN_NHC_UDP_4BIT_PORT)) { 520 pr_debug("UDP header: both ports compression to 4 bits\n"); 521 /* compression value */ 522 tmp = LOWPAN_NHC_UDP_CS_P_11; 523 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 524 /* source and destination port */ 525 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT + 526 ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4); 527 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 528 } else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) == 529 LOWPAN_NHC_UDP_8BIT_PORT) { 530 pr_debug("UDP header: remove 8 bits of dest\n"); 531 /* compression value */ 532 tmp = LOWPAN_NHC_UDP_CS_P_01; 533 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 534 /* source port */ 535 lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source)); 536 /* destination port */ 537 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT; 538 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 539 } else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) == 540 LOWPAN_NHC_UDP_8BIT_PORT) { 541 pr_debug("UDP header: remove 8 bits of source\n"); 542 /* compression value */ 543 tmp = LOWPAN_NHC_UDP_CS_P_10; 544 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 545 /* source port */ 546 tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT; 547 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 548 /* destination port */ 549 lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest)); 550 } else { 551 pr_debug("UDP header: can't compress\n"); 552 /* compression value */ 553 tmp = LOWPAN_NHC_UDP_CS_P_00; 554 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 555 /* source port */ 556 lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source)); 557 /* destination port */ 558 lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest)); 559 } 560 561 /* checksum is always inline */ 562 lowpan_push_hc_data(hc_ptr, &uh->check, sizeof(uh->check)); 563 564 /* skip the UDP header */ 565 skb_pull(skb, sizeof(struct udphdr)); 566 } 567 568 int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev, 569 unsigned short type, const void *_daddr, 570 const void *_saddr, unsigned int len) 571 { 572 u8 tmp, iphc0, iphc1, *hc_ptr; 573 struct ipv6hdr *hdr; 574 u8 head[100] = {}; 575 int addr_type; 576 577 if (type != ETH_P_IPV6) 578 return -EINVAL; 579 580 hdr = ipv6_hdr(skb); 581 hc_ptr = head + 2; 582 583 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n" 584 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n", 585 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr, 586 hdr->hop_limit, &hdr->daddr); 587 588 raw_dump_table(__func__, "raw skb network header dump", 589 skb_network_header(skb), sizeof(struct ipv6hdr)); 590 591 /* As we copy some bit-length fields, in the IPHC encoding bytes, 592 * we sometimes use |= 593 * If the field is 0, and the current bit value in memory is 1, 594 * this does not work. We therefore reset the IPHC encoding here 595 */ 596 iphc0 = LOWPAN_DISPATCH_IPHC; 597 iphc1 = 0; 598 599 /* TODO: context lookup */ 600 601 raw_dump_inline(__func__, "saddr", 602 (unsigned char *)_saddr, IEEE802154_ADDR_LEN); 603 raw_dump_inline(__func__, "daddr", 604 (unsigned char *)_daddr, IEEE802154_ADDR_LEN); 605 606 raw_dump_table(__func__, "sending raw skb network uncompressed packet", 607 skb->data, skb->len); 608 609 /* Traffic class, flow label 610 * If flow label is 0, compress it. If traffic class is 0, compress it 611 * We have to process both in the same time as the offset of traffic 612 * class depends on the presence of version and flow label 613 */ 614 615 /* hc format of TC is ECN | DSCP , original one is DSCP | ECN */ 616 tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4); 617 tmp = ((tmp & 0x03) << 6) | (tmp >> 2); 618 619 if (((hdr->flow_lbl[0] & 0x0F) == 0) && 620 (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) { 621 /* flow label can be compressed */ 622 iphc0 |= LOWPAN_IPHC_FL_C; 623 if ((hdr->priority == 0) && 624 ((hdr->flow_lbl[0] & 0xF0) == 0)) { 625 /* compress (elide) all */ 626 iphc0 |= LOWPAN_IPHC_TC_C; 627 } else { 628 /* compress only the flow label */ 629 *hc_ptr = tmp; 630 hc_ptr += 1; 631 } 632 } else { 633 /* Flow label cannot be compressed */ 634 if ((hdr->priority == 0) && 635 ((hdr->flow_lbl[0] & 0xF0) == 0)) { 636 /* compress only traffic class */ 637 iphc0 |= LOWPAN_IPHC_TC_C; 638 *hc_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F); 639 memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2); 640 hc_ptr += 3; 641 } else { 642 /* compress nothing */ 643 memcpy(hc_ptr, hdr, 4); 644 /* replace the top byte with new ECN | DSCP format */ 645 *hc_ptr = tmp; 646 hc_ptr += 4; 647 } 648 } 649 650 /* NOTE: payload length is always compressed */ 651 652 /* Next Header is compress if UDP */ 653 if (hdr->nexthdr == UIP_PROTO_UDP) 654 iphc0 |= LOWPAN_IPHC_NH_C; 655 656 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) 657 lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr, 658 sizeof(hdr->nexthdr)); 659 660 /* Hop limit 661 * if 1: compress, encoding is 01 662 * if 64: compress, encoding is 10 663 * if 255: compress, encoding is 11 664 * else do not compress 665 */ 666 switch (hdr->hop_limit) { 667 case 1: 668 iphc0 |= LOWPAN_IPHC_TTL_1; 669 break; 670 case 64: 671 iphc0 |= LOWPAN_IPHC_TTL_64; 672 break; 673 case 255: 674 iphc0 |= LOWPAN_IPHC_TTL_255; 675 break; 676 default: 677 lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit, 678 sizeof(hdr->hop_limit)); 679 } 680 681 addr_type = ipv6_addr_type(&hdr->saddr); 682 /* source address compression */ 683 if (addr_type == IPV6_ADDR_ANY) { 684 pr_debug("source address is unspecified, setting SAC\n"); 685 iphc1 |= LOWPAN_IPHC_SAC; 686 } else { 687 if (addr_type & IPV6_ADDR_LINKLOCAL) { 688 iphc1 |= lowpan_compress_addr_64(&hc_ptr, 689 LOWPAN_IPHC_SAM_BIT, 690 &hdr->saddr, _saddr); 691 pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n", 692 &hdr->saddr, iphc1); 693 } else { 694 pr_debug("send the full source address\n"); 695 lowpan_push_hc_data(&hc_ptr, hdr->saddr.s6_addr, 16); 696 } 697 } 698 699 addr_type = ipv6_addr_type(&hdr->daddr); 700 /* destination address compression */ 701 if (addr_type & IPV6_ADDR_MULTICAST) { 702 pr_debug("destination address is multicast: "); 703 iphc1 |= LOWPAN_IPHC_M; 704 if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) { 705 pr_debug("compressed to 1 octet\n"); 706 iphc1 |= LOWPAN_IPHC_DAM_11; 707 /* use last byte */ 708 lowpan_push_hc_data(&hc_ptr, 709 &hdr->daddr.s6_addr[15], 1); 710 } else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) { 711 pr_debug("compressed to 4 octets\n"); 712 iphc1 |= LOWPAN_IPHC_DAM_10; 713 /* second byte + the last three */ 714 lowpan_push_hc_data(&hc_ptr, 715 &hdr->daddr.s6_addr[1], 1); 716 lowpan_push_hc_data(&hc_ptr, 717 &hdr->daddr.s6_addr[13], 3); 718 } else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) { 719 pr_debug("compressed to 6 octets\n"); 720 iphc1 |= LOWPAN_IPHC_DAM_01; 721 /* second byte + the last five */ 722 lowpan_push_hc_data(&hc_ptr, 723 &hdr->daddr.s6_addr[1], 1); 724 lowpan_push_hc_data(&hc_ptr, 725 &hdr->daddr.s6_addr[11], 5); 726 } else { 727 pr_debug("using full address\n"); 728 iphc1 |= LOWPAN_IPHC_DAM_00; 729 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16); 730 } 731 } else { 732 if (addr_type & IPV6_ADDR_LINKLOCAL) { 733 /* TODO: context lookup */ 734 iphc1 |= lowpan_compress_addr_64(&hc_ptr, 735 LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr); 736 pr_debug("dest address unicast link-local %pI6c " 737 "iphc1 0x%02x\n", &hdr->daddr, iphc1); 738 } else { 739 pr_debug("dest address unicast %pI6c\n", &hdr->daddr); 740 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16); 741 } 742 } 743 744 /* UDP header compression */ 745 if (hdr->nexthdr == UIP_PROTO_UDP) 746 compress_udp_header(&hc_ptr, skb); 747 748 head[0] = iphc0; 749 head[1] = iphc1; 750 751 skb_pull(skb, sizeof(struct ipv6hdr)); 752 skb_reset_transport_header(skb); 753 memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head); 754 skb_reset_network_header(skb); 755 756 pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len); 757 758 raw_dump_table(__func__, "raw skb data dump compressed", 759 skb->data, skb->len); 760 return 0; 761 } 762 EXPORT_SYMBOL_GPL(lowpan_header_compress); 763 764 MODULE_LICENSE("GPL"); 765