iphc.c revision 85c71240a3e6c151038d9ed3fa88fc0fb80043fb
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/6lowpan.h> 58#include <net/ipv6.h> 59#include <net/af_ieee802154.h> 60 61/* 62 * Uncompress address function for source and 63 * destination address(non-multicast). 64 * 65 * address_mode is sam value or dam value. 66 */ 67static int uncompress_addr(struct sk_buff *skb, 68 struct in6_addr *ipaddr, const u8 address_mode, 69 const u8 *lladdr, const u8 addr_type, 70 const u8 addr_len) 71{ 72 bool fail; 73 74 switch (address_mode) { 75 case LOWPAN_IPHC_ADDR_00: 76 /* for global link addresses */ 77 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16); 78 break; 79 case LOWPAN_IPHC_ADDR_01: 80 /* fe:80::XXXX:XXXX:XXXX:XXXX */ 81 ipaddr->s6_addr[0] = 0xFE; 82 ipaddr->s6_addr[1] = 0x80; 83 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8); 84 break; 85 case LOWPAN_IPHC_ADDR_02: 86 /* fe:80::ff:fe00:XXXX */ 87 ipaddr->s6_addr[0] = 0xFE; 88 ipaddr->s6_addr[1] = 0x80; 89 ipaddr->s6_addr[11] = 0xFF; 90 ipaddr->s6_addr[12] = 0xFE; 91 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2); 92 break; 93 case LOWPAN_IPHC_ADDR_03: 94 fail = false; 95 switch (addr_type) { 96 case IEEE802154_ADDR_LONG: 97 /* fe:80::XXXX:XXXX:XXXX:XXXX 98 * \_________________/ 99 * hwaddr 100 */ 101 ipaddr->s6_addr[0] = 0xFE; 102 ipaddr->s6_addr[1] = 0x80; 103 memcpy(&ipaddr->s6_addr[8], lladdr, addr_len); 104 /* second bit-flip (Universe/Local) 105 * is done according RFC2464 106 */ 107 ipaddr->s6_addr[8] ^= 0x02; 108 break; 109 case IEEE802154_ADDR_SHORT: 110 /* fe:80::ff:fe00:XXXX 111 * \__/ 112 * short_addr 113 * 114 * Universe/Local bit is zero. 115 */ 116 ipaddr->s6_addr[0] = 0xFE; 117 ipaddr->s6_addr[1] = 0x80; 118 ipaddr->s6_addr[11] = 0xFF; 119 ipaddr->s6_addr[12] = 0xFE; 120 ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr)); 121 break; 122 default: 123 pr_debug("Invalid addr_type set\n"); 124 return -EINVAL; 125 } 126 break; 127 default: 128 pr_debug("Invalid address mode value: 0x%x\n", address_mode); 129 return -EINVAL; 130 } 131 132 if (fail) { 133 pr_debug("Failed to fetch skb data\n"); 134 return -EIO; 135 } 136 137 raw_dump_inline(NULL, "Reconstructed ipv6 addr is", 138 ipaddr->s6_addr, 16); 139 140 return 0; 141} 142 143/* 144 * Uncompress address function for source context 145 * based address(non-multicast). 146 */ 147static int uncompress_context_based_src_addr(struct sk_buff *skb, 148 struct in6_addr *ipaddr, 149 const u8 sam) 150{ 151 switch (sam) { 152 case LOWPAN_IPHC_ADDR_00: 153 /* unspec address :: 154 * Do nothing, address is already :: 155 */ 156 break; 157 case LOWPAN_IPHC_ADDR_01: 158 /* TODO */ 159 case LOWPAN_IPHC_ADDR_02: 160 /* TODO */ 161 case LOWPAN_IPHC_ADDR_03: 162 /* TODO */ 163 netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam); 164 return -EINVAL; 165 default: 166 pr_debug("Invalid sam value: 0x%x\n", sam); 167 return -EINVAL; 168 } 169 170 raw_dump_inline(NULL, 171 "Reconstructed context based ipv6 src addr is", 172 ipaddr->s6_addr, 16); 173 174 return 0; 175} 176 177static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr, 178 struct net_device *dev, skb_delivery_cb deliver_skb) 179{ 180 struct sk_buff *new; 181 int stat; 182 183 new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb), 184 GFP_ATOMIC); 185 kfree_skb(skb); 186 187 if (!new) 188 return -ENOMEM; 189 190 skb_push(new, sizeof(struct ipv6hdr)); 191 skb_reset_network_header(new); 192 skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr)); 193 194 new->protocol = htons(ETH_P_IPV6); 195 new->pkt_type = PACKET_HOST; 196 new->dev = dev; 197 198 raw_dump_table(__func__, "raw skb data dump before receiving", 199 new->data, new->len); 200 201 stat = deliver_skb(new, dev); 202 203 kfree_skb(new); 204 205 return stat; 206} 207 208/* Uncompress function for multicast destination address, 209 * when M bit is set. 210 */ 211static int 212lowpan_uncompress_multicast_daddr(struct sk_buff *skb, 213 struct in6_addr *ipaddr, 214 const u8 dam) 215{ 216 bool fail; 217 218 switch (dam) { 219 case LOWPAN_IPHC_DAM_00: 220 /* 00: 128 bits. The full address 221 * is carried in-line. 222 */ 223 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16); 224 break; 225 case LOWPAN_IPHC_DAM_01: 226 /* 01: 48 bits. The address takes 227 * the form ffXX::00XX:XXXX:XXXX. 228 */ 229 ipaddr->s6_addr[0] = 0xFF; 230 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1); 231 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5); 232 break; 233 case LOWPAN_IPHC_DAM_10: 234 /* 10: 32 bits. The address takes 235 * the form ffXX::00XX:XXXX. 236 */ 237 ipaddr->s6_addr[0] = 0xFF; 238 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1); 239 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3); 240 break; 241 case LOWPAN_IPHC_DAM_11: 242 /* 11: 8 bits. The address takes 243 * the form ff02::00XX. 244 */ 245 ipaddr->s6_addr[0] = 0xFF; 246 ipaddr->s6_addr[1] = 0x02; 247 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1); 248 break; 249 default: 250 pr_debug("DAM value has a wrong value: 0x%x\n", dam); 251 return -EINVAL; 252 } 253 254 if (fail) { 255 pr_debug("Failed to fetch skb data\n"); 256 return -EIO; 257 } 258 259 raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is", 260 ipaddr->s6_addr, 16); 261 262 return 0; 263} 264 265static int 266uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh) 267{ 268 bool fail; 269 u8 tmp = 0, val = 0; 270 271 if (!uh) 272 goto err; 273 274 fail = lowpan_fetch_skb(skb, &tmp, sizeof(tmp)); 275 276 if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) { 277 pr_debug("UDP header uncompression\n"); 278 switch (tmp & LOWPAN_NHC_UDP_CS_P_11) { 279 case LOWPAN_NHC_UDP_CS_P_00: 280 fail |= lowpan_fetch_skb(skb, &uh->source, 281 sizeof(uh->source)); 282 fail |= lowpan_fetch_skb(skb, &uh->dest, 283 sizeof(uh->dest)); 284 break; 285 case LOWPAN_NHC_UDP_CS_P_01: 286 fail |= lowpan_fetch_skb(skb, &uh->source, 287 sizeof(uh->source)); 288 fail |= lowpan_fetch_skb(skb, &val, sizeof(val)); 289 uh->dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT); 290 break; 291 case LOWPAN_NHC_UDP_CS_P_10: 292 fail |= lowpan_fetch_skb(skb, &val, sizeof(val)); 293 uh->source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT); 294 fail |= lowpan_fetch_skb(skb, &uh->dest, 295 sizeof(uh->dest)); 296 break; 297 case LOWPAN_NHC_UDP_CS_P_11: 298 fail |= lowpan_fetch_skb(skb, &val, sizeof(val)); 299 uh->source = htons(LOWPAN_NHC_UDP_4BIT_PORT + 300 (val >> 4)); 301 uh->dest = htons(LOWPAN_NHC_UDP_4BIT_PORT + 302 (val & 0x0f)); 303 break; 304 default: 305 pr_debug("ERROR: unknown UDP format\n"); 306 goto err; 307 break; 308 } 309 310 pr_debug("uncompressed UDP ports: src = %d, dst = %d\n", 311 ntohs(uh->source), ntohs(uh->dest)); 312 313 /* checksum */ 314 if (tmp & LOWPAN_NHC_UDP_CS_C) { 315 pr_debug_ratelimited("checksum elided currently not supported\n"); 316 goto err; 317 } else { 318 fail |= lowpan_fetch_skb(skb, &uh->check, 319 sizeof(uh->check)); 320 } 321 322 /* 323 * UDP lenght needs to be infered from the lower layers 324 * here, we obtain the hint from the remaining size of the 325 * frame 326 */ 327 uh->len = htons(skb->len + sizeof(struct udphdr)); 328 pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len)); 329 } else { 330 pr_debug("ERROR: unsupported NH format\n"); 331 goto err; 332 } 333 334 if (fail) 335 goto err; 336 337 return 0; 338err: 339 return -EINVAL; 340} 341 342/* TTL uncompression values */ 343static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 }; 344 345int lowpan_process_data(struct sk_buff *skb, struct net_device *dev, 346 const u8 *saddr, const u8 saddr_type, const u8 saddr_len, 347 const u8 *daddr, const u8 daddr_type, const u8 daddr_len, 348 u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb) 349{ 350 struct ipv6hdr hdr = {}; 351 u8 tmp, num_context = 0; 352 int err; 353 354 raw_dump_table(__func__, "raw skb data dump uncompressed", 355 skb->data, skb->len); 356 357 /* another if the CID flag is set */ 358 if (iphc1 & LOWPAN_IPHC_CID) { 359 pr_debug("CID flag is set, increase header with one\n"); 360 if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context))) 361 goto drop; 362 } 363 364 hdr.version = 6; 365 366 /* Traffic Class and Flow Label */ 367 switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) { 368 /* 369 * Traffic Class and FLow Label carried in-line 370 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) 371 */ 372 case 0: /* 00b */ 373 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) 374 goto drop; 375 376 memcpy(&hdr.flow_lbl, &skb->data[0], 3); 377 skb_pull(skb, 3); 378 hdr.priority = ((tmp >> 2) & 0x0f); 379 hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) | 380 (hdr.flow_lbl[0] & 0x0f); 381 break; 382 /* 383 * Traffic class carried in-line 384 * ECN + DSCP (1 byte), Flow Label is elided 385 */ 386 case 2: /* 10b */ 387 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) 388 goto drop; 389 390 hdr.priority = ((tmp >> 2) & 0x0f); 391 hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30); 392 break; 393 /* 394 * Flow Label carried in-line 395 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided 396 */ 397 case 1: /* 01b */ 398 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) 399 goto drop; 400 401 hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30); 402 memcpy(&hdr.flow_lbl[1], &skb->data[0], 2); 403 skb_pull(skb, 2); 404 break; 405 /* Traffic Class and Flow Label are elided */ 406 case 3: /* 11b */ 407 break; 408 default: 409 break; 410 } 411 412 /* Next Header */ 413 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) { 414 /* Next header is carried inline */ 415 if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr))) 416 goto drop; 417 418 pr_debug("NH flag is set, next header carried inline: %02x\n", 419 hdr.nexthdr); 420 } 421 422 /* Hop Limit */ 423 if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) 424 hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03]; 425 else { 426 if (lowpan_fetch_skb(skb, &hdr.hop_limit, 427 sizeof(hdr.hop_limit))) 428 goto drop; 429 } 430 431 /* Extract SAM to the tmp variable */ 432 tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03; 433 434 if (iphc1 & LOWPAN_IPHC_SAC) { 435 /* Source address context based uncompression */ 436 pr_debug("SAC bit is set. Handle context based source address.\n"); 437 err = uncompress_context_based_src_addr( 438 skb, &hdr.saddr, tmp); 439 } else { 440 /* Source address uncompression */ 441 pr_debug("source address stateless compression\n"); 442 err = uncompress_addr(skb, &hdr.saddr, tmp, saddr, 443 saddr_type, saddr_len); 444 } 445 446 /* Check on error of previous branch */ 447 if (err) 448 goto drop; 449 450 /* Extract DAM to the tmp variable */ 451 tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03; 452 453 /* check for Multicast Compression */ 454 if (iphc1 & LOWPAN_IPHC_M) { 455 if (iphc1 & LOWPAN_IPHC_DAC) { 456 pr_debug("dest: context-based mcast compression\n"); 457 /* TODO: implement this */ 458 } else { 459 err = lowpan_uncompress_multicast_daddr( 460 skb, &hdr.daddr, tmp); 461 if (err) 462 goto drop; 463 } 464 } else { 465 err = uncompress_addr(skb, &hdr.daddr, tmp, daddr, 466 daddr_type, daddr_len); 467 pr_debug("dest: stateless compression mode %d dest %pI6c\n", 468 tmp, &hdr.daddr); 469 if (err) 470 goto drop; 471 } 472 473 /* UDP data uncompression */ 474 if (iphc0 & LOWPAN_IPHC_NH_C) { 475 struct udphdr uh; 476 struct sk_buff *new; 477 if (uncompress_udp_header(skb, &uh)) 478 goto drop; 479 480 /* 481 * replace the compressed UDP head by the uncompressed UDP 482 * header 483 */ 484 new = skb_copy_expand(skb, sizeof(struct udphdr), 485 skb_tailroom(skb), GFP_ATOMIC); 486 kfree_skb(skb); 487 488 if (!new) 489 return -ENOMEM; 490 491 skb = new; 492 493 skb_push(skb, sizeof(struct udphdr)); 494 skb_reset_transport_header(skb); 495 skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr)); 496 497 raw_dump_table(__func__, "raw UDP header dump", 498 (u8 *)&uh, sizeof(uh)); 499 500 hdr.nexthdr = UIP_PROTO_UDP; 501 } 502 503 hdr.payload_len = htons(skb->len); 504 505 pr_debug("skb headroom size = %d, data length = %d\n", 506 skb_headroom(skb), skb->len); 507 508 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t" 509 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n", 510 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr, 511 hdr.hop_limit, &hdr.daddr); 512 513 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, 514 sizeof(hdr)); 515 516 return skb_deliver(skb, &hdr, dev, deliver_skb); 517 518drop: 519 kfree_skb(skb); 520 return -EINVAL; 521} 522EXPORT_SYMBOL_GPL(lowpan_process_data); 523 524static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift, 525 const struct in6_addr *ipaddr, 526 const unsigned char *lladdr) 527{ 528 u8 val = 0; 529 530 if (is_addr_mac_addr_based(ipaddr, lladdr)) { 531 val = 3; /* 0-bits */ 532 pr_debug("address compression 0 bits\n"); 533 } else if (lowpan_is_iid_16_bit_compressable(ipaddr)) { 534 /* compress IID to 16 bits xxxx::XXXX */ 535 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2); 536 val = 2; /* 16-bits */ 537 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)", 538 *hc_ptr - 2, 2); 539 } else { 540 /* do not compress IID => xxxx::IID */ 541 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8); 542 val = 1; /* 64-bits */ 543 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)", 544 *hc_ptr - 8, 8); 545 } 546 547 return rol8(val, shift); 548} 549 550static void compress_udp_header(u8 **hc_ptr, struct sk_buff *skb) 551{ 552 struct udphdr *uh = udp_hdr(skb); 553 u8 tmp; 554 555 if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) == 556 LOWPAN_NHC_UDP_4BIT_PORT) && 557 ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) == 558 LOWPAN_NHC_UDP_4BIT_PORT)) { 559 pr_debug("UDP header: both ports compression to 4 bits\n"); 560 /* compression value */ 561 tmp = LOWPAN_NHC_UDP_CS_P_11; 562 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 563 /* source and destination port */ 564 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT + 565 ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4); 566 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 567 } else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) == 568 LOWPAN_NHC_UDP_8BIT_PORT) { 569 pr_debug("UDP header: remove 8 bits of dest\n"); 570 /* compression value */ 571 tmp = LOWPAN_NHC_UDP_CS_P_01; 572 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 573 /* source port */ 574 lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source)); 575 /* destination port */ 576 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT; 577 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 578 } else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) == 579 LOWPAN_NHC_UDP_8BIT_PORT) { 580 pr_debug("UDP header: remove 8 bits of source\n"); 581 /* compression value */ 582 tmp = LOWPAN_NHC_UDP_CS_P_10; 583 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 584 /* source port */ 585 tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT; 586 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 587 /* destination port */ 588 lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest)); 589 } else { 590 pr_debug("UDP header: can't compress\n"); 591 /* compression value */ 592 tmp = LOWPAN_NHC_UDP_CS_P_00; 593 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp)); 594 /* source port */ 595 lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source)); 596 /* destination port */ 597 lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest)); 598 } 599 600 /* checksum is always inline */ 601 lowpan_push_hc_data(hc_ptr, &uh->check, sizeof(uh->check)); 602 603 /* skip the UDP header */ 604 skb_pull(skb, sizeof(struct udphdr)); 605} 606 607int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev, 608 unsigned short type, const void *_daddr, 609 const void *_saddr, unsigned int len) 610{ 611 u8 tmp, iphc0, iphc1, *hc_ptr; 612 struct ipv6hdr *hdr; 613 u8 head[100] = {}; 614 615 if (type != ETH_P_IPV6) 616 return -EINVAL; 617 618 hdr = ipv6_hdr(skb); 619 hc_ptr = head + 2; 620 621 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n" 622 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n", 623 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr, 624 hdr->hop_limit, &hdr->daddr); 625 626 raw_dump_table(__func__, "raw skb network header dump", 627 skb_network_header(skb), sizeof(struct ipv6hdr)); 628 629 /* 630 * As we copy some bit-length fields, in the IPHC encoding bytes, 631 * we sometimes use |= 632 * If the field is 0, and the current bit value in memory is 1, 633 * this does not work. We therefore reset the IPHC encoding here 634 */ 635 iphc0 = LOWPAN_DISPATCH_IPHC; 636 iphc1 = 0; 637 638 /* TODO: context lookup */ 639 640 raw_dump_inline(__func__, "saddr", 641 (unsigned char *)_saddr, IEEE802154_ADDR_LEN); 642 raw_dump_inline(__func__, "daddr", 643 (unsigned char *)_daddr, IEEE802154_ADDR_LEN); 644 645 raw_dump_table(__func__, 646 "sending raw skb network uncompressed packet", 647 skb->data, skb->len); 648 649 /* 650 * Traffic class, flow label 651 * If flow label is 0, compress it. If traffic class is 0, compress it 652 * We have to process both in the same time as the offset of traffic 653 * class depends on the presence of version and flow label 654 */ 655 656 /* hc format of TC is ECN | DSCP , original one is DSCP | ECN */ 657 tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4); 658 tmp = ((tmp & 0x03) << 6) | (tmp >> 2); 659 660 if (((hdr->flow_lbl[0] & 0x0F) == 0) && 661 (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) { 662 /* flow label can be compressed */ 663 iphc0 |= LOWPAN_IPHC_FL_C; 664 if ((hdr->priority == 0) && 665 ((hdr->flow_lbl[0] & 0xF0) == 0)) { 666 /* compress (elide) all */ 667 iphc0 |= LOWPAN_IPHC_TC_C; 668 } else { 669 /* compress only the flow label */ 670 *hc_ptr = tmp; 671 hc_ptr += 1; 672 } 673 } else { 674 /* Flow label cannot be compressed */ 675 if ((hdr->priority == 0) && 676 ((hdr->flow_lbl[0] & 0xF0) == 0)) { 677 /* compress only traffic class */ 678 iphc0 |= LOWPAN_IPHC_TC_C; 679 *hc_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F); 680 memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2); 681 hc_ptr += 3; 682 } else { 683 /* compress nothing */ 684 memcpy(hc_ptr, hdr, 4); 685 /* replace the top byte with new ECN | DSCP format */ 686 *hc_ptr = tmp; 687 hc_ptr += 4; 688 } 689 } 690 691 /* NOTE: payload length is always compressed */ 692 693 /* Next Header is compress if UDP */ 694 if (hdr->nexthdr == UIP_PROTO_UDP) 695 iphc0 |= LOWPAN_IPHC_NH_C; 696 697 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) 698 lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr, 699 sizeof(hdr->nexthdr)); 700 701 /* 702 * Hop limit 703 * if 1: compress, encoding is 01 704 * if 64: compress, encoding is 10 705 * if 255: compress, encoding is 11 706 * else do not compress 707 */ 708 switch (hdr->hop_limit) { 709 case 1: 710 iphc0 |= LOWPAN_IPHC_TTL_1; 711 break; 712 case 64: 713 iphc0 |= LOWPAN_IPHC_TTL_64; 714 break; 715 case 255: 716 iphc0 |= LOWPAN_IPHC_TTL_255; 717 break; 718 default: 719 lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit, 720 sizeof(hdr->hop_limit)); 721 } 722 723 /* source address compression */ 724 if (is_addr_unspecified(&hdr->saddr)) { 725 pr_debug("source address is unspecified, setting SAC\n"); 726 iphc1 |= LOWPAN_IPHC_SAC; 727 /* TODO: context lookup */ 728 } else if (is_addr_link_local(&hdr->saddr)) { 729 iphc1 |= lowpan_compress_addr_64(&hc_ptr, 730 LOWPAN_IPHC_SAM_BIT, &hdr->saddr, _saddr); 731 pr_debug("source address unicast link-local %pI6c " 732 "iphc1 0x%02x\n", &hdr->saddr, iphc1); 733 } else { 734 pr_debug("send the full source address\n"); 735 lowpan_push_hc_data(&hc_ptr, &hdr->saddr.s6_addr[0], 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 lowpan_push_hc_data(&hc_ptr, 747 &hdr->daddr.s6_addr[15], 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 lowpan_push_hc_data(&hc_ptr, 753 &hdr->daddr.s6_addr[1], 1); 754 lowpan_push_hc_data(&hc_ptr, 755 &hdr->daddr.s6_addr[13], 3); 756 } else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) { 757 pr_debug("compressed to 6 octets\n"); 758 iphc1 |= LOWPAN_IPHC_DAM_01; 759 /* second byte + the last five */ 760 lowpan_push_hc_data(&hc_ptr, 761 &hdr->daddr.s6_addr[1], 1); 762 lowpan_push_hc_data(&hc_ptr, 763 &hdr->daddr.s6_addr[11], 5); 764 } else { 765 pr_debug("using full address\n"); 766 iphc1 |= LOWPAN_IPHC_DAM_00; 767 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16); 768 } 769 } else { 770 /* TODO: context lookup */ 771 if (is_addr_link_local(&hdr->daddr)) { 772 iphc1 |= lowpan_compress_addr_64(&hc_ptr, 773 LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr); 774 pr_debug("dest address unicast link-local %pI6c " 775 "iphc1 0x%02x\n", &hdr->daddr, iphc1); 776 } else { 777 pr_debug("dest address unicast %pI6c\n", &hdr->daddr); 778 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16); 779 } 780 } 781 782 /* UDP header compression */ 783 if (hdr->nexthdr == UIP_PROTO_UDP) 784 compress_udp_header(&hc_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, hc_ptr - head), head, hc_ptr - head); 792 skb_reset_network_header(skb); 793 794 pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len); 795 796 raw_dump_table(__func__, "raw skb data dump compressed", 797 skb->data, skb->len); 798 return 0; 799} 800EXPORT_SYMBOL_GPL(lowpan_header_compress); 801 802MODULE_LICENSE("GPL"); 803