1 /** 2 * @file 3 * 4 * Common 6LowPAN routines for IPv6. Uses ND tables for link-layer addressing. Fragments packets to 6LowPAN units. 5 * 6 * This implementation aims to conform to IEEE 802.15.4(-2015), RFC 4944 and RFC 6282. 7 * @todo: RFC 6775. 8 */ 9 10 /* 11 * Copyright (c) 2015 Inico Technologies Ltd. 12 * All rights reserved. 13 * 14 * Redistribution and use in source and binary forms, with or without modification, 15 * are permitted provided that the following conditions are met: 16 * 17 * 1. Redistributions of source code must retain the above copyright notice, 18 * this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright notice, 20 * this list of conditions and the following disclaimer in the documentation 21 * and/or other materials provided with the distribution. 22 * 3. The name of the author may not be used to endorse or promote products 23 * derived from this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 26 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 27 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 28 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 29 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 30 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 33 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 34 * OF SUCH DAMAGE. 35 * 36 * This file is part of the lwIP TCP/IP stack. 37 * 38 * Author: Ivan Delamer <[email protected]> 39 * 40 * 41 * Please coordinate changes and requests with Ivan Delamer 42 * <[email protected]> 43 */ 44 45 /** 46 * @defgroup sixlowpan 6LoWPAN (RFC4944) 47 * @ingroup netifs 48 * 6LowPAN netif implementation 49 */ 50 51 #include "netif/lowpan6_common.h" 52 53 #if LWIP_IPV6 54 55 #include "lwip/ip.h" 56 #include "lwip/pbuf.h" 57 #include "lwip/ip_addr.h" 58 #include "lwip/netif.h" 59 #include "lwip/udp.h" 60 61 #include <string.h> 62 63 /* Determine compression mode for unicast address. */ 64 s8_t 65 lowpan6_get_address_mode(const ip6_addr_t *ip6addr, const struct lowpan6_link_addr *mac_addr) 66 { 67 if (mac_addr->addr_len == 2) { 68 if ((ip6addr->addr[2] == (u32_t)PP_HTONL(0x000000ff)) && 69 ((ip6addr->addr[3] & PP_HTONL(0xffff0000)) == PP_NTOHL(0xfe000000))) { 70 if ((ip6addr->addr[3] & PP_HTONL(0x0000ffff)) == lwip_ntohl((mac_addr->addr[0] << 8) | mac_addr->addr[1])) { 71 return 3; 72 } 73 } 74 } else if (mac_addr->addr_len == 8) { 75 if ((ip6addr->addr[2] == lwip_ntohl(((mac_addr->addr[0] ^ 2) << 24) | (mac_addr->addr[1] << 16) | mac_addr->addr[2] << 8 | mac_addr->addr[3])) && 76 (ip6addr->addr[3] == lwip_ntohl((mac_addr->addr[4] << 24) | (mac_addr->addr[5] << 16) | mac_addr->addr[6] << 8 | mac_addr->addr[7]))) { 77 return 3; 78 } 79 } 80 81 if ((ip6addr->addr[2] == PP_HTONL(0x000000ffUL)) && 82 ((ip6addr->addr[3] & PP_HTONL(0xffff0000)) == PP_NTOHL(0xfe000000UL))) { 83 return 2; 84 } 85 86 return 1; 87 } 88 89 #if LWIP_6LOWPAN_IPHC 90 91 /* Determine compression mode for multicast address. */ 92 static s8_t 93 lowpan6_get_address_mode_mc(const ip6_addr_t *ip6addr) 94 { 95 if ((ip6addr->addr[0] == PP_HTONL(0xff020000)) && 96 (ip6addr->addr[1] == 0) && 97 (ip6addr->addr[2] == 0) && 98 ((ip6addr->addr[3] & PP_HTONL(0xffffff00)) == 0)) { 99 return 3; 100 } else if (((ip6addr->addr[0] & PP_HTONL(0xff00ffff)) == PP_HTONL(0xff000000)) && 101 (ip6addr->addr[1] == 0)) { 102 if ((ip6addr->addr[2] == 0) && 103 ((ip6addr->addr[3] & PP_HTONL(0xff000000)) == 0)) { 104 return 2; 105 } else if ((ip6addr->addr[2] & PP_HTONL(0xffffff00)) == 0) { 106 return 1; 107 } 108 } 109 110 return 0; 111 } 112 113 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0 114 static s8_t 115 lowpan6_context_lookup(const ip6_addr_t *lowpan6_contexts, const ip6_addr_t *ip6addr) 116 { 117 s8_t i; 118 119 for (i = 0; i < LWIP_6LOWPAN_NUM_CONTEXTS; i++) { 120 if (ip6_addr_netcmp(&lowpan6_contexts[i], ip6addr)) { 121 return i; 122 } 123 } 124 return -1; 125 } 126 #endif /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */ 127 128 /* 129 * Compress IPv6 and/or UDP headers. 130 * */ 131 err_t 132 lowpan6_compress_headers(struct netif *netif, u8_t *inbuf, size_t inbuf_size, u8_t *outbuf, size_t outbuf_size, 133 u8_t *lowpan6_header_len_out, u8_t *hidden_header_len_out, ip6_addr_t *lowpan6_contexts, 134 const struct lowpan6_link_addr *src, const struct lowpan6_link_addr *dst) 135 { 136 u8_t *buffer, *inptr; 137 u8_t lowpan6_header_len; 138 u8_t hidden_header_len = 0; 139 s8_t i; 140 struct ip6_hdr *ip6hdr; 141 ip_addr_t ip6src, ip6dst; 142 143 LWIP_ASSERT("netif != NULL", netif != NULL); 144 LWIP_ASSERT("inbuf != NULL", inbuf != NULL); 145 LWIP_ASSERT("outbuf != NULL", outbuf != NULL); 146 LWIP_ASSERT("lowpan6_header_len_out != NULL", lowpan6_header_len_out != NULL); 147 LWIP_ASSERT("hidden_header_len_out != NULL", hidden_header_len_out != NULL); 148 149 /* Perform 6LowPAN IPv6 header compression according to RFC 6282 */ 150 buffer = outbuf; 151 inptr = inbuf; 152 153 if (inbuf_size < IP6_HLEN) { 154 /* input buffer too short */ 155 return ERR_VAL; 156 } 157 if (outbuf_size < IP6_HLEN) { 158 /* output buffer too short for worst case */ 159 return ERR_MEM; 160 } 161 162 /* Point to ip6 header and align copies of src/dest addresses. */ 163 ip6hdr = (struct ip6_hdr *)inptr; 164 ip_addr_copy_from_ip6_packed(ip6dst, ip6hdr->dest); 165 ip6_addr_assign_zone(ip_2_ip6(&ip6dst), IP6_UNKNOWN, netif); 166 ip_addr_copy_from_ip6_packed(ip6src, ip6hdr->src); 167 ip6_addr_assign_zone(ip_2_ip6(&ip6src), IP6_UNKNOWN, netif); 168 169 /* Basic length of 6LowPAN header, set dispatch and clear fields. */ 170 lowpan6_header_len = 2; 171 buffer[0] = 0x60; 172 buffer[1] = 0; 173 174 /* Determine whether there will be a Context Identifier Extension byte or not. 175 * If so, set it already. */ 176 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0 177 buffer[2] = 0; 178 179 i = lowpan6_context_lookup(lowpan6_contexts, ip_2_ip6(&ip6src)); 180 if (i >= 0) { 181 /* Stateful source address compression. */ 182 buffer[1] |= 0x40; 183 buffer[2] |= (i & 0x0f) << 4; 184 } 185 186 i = lowpan6_context_lookup(lowpan6_contexts, ip_2_ip6(&ip6dst)); 187 if (i >= 0) { 188 /* Stateful destination address compression. */ 189 buffer[1] |= 0x04; 190 buffer[2] |= i & 0x0f; 191 } 192 193 if (buffer[2] != 0x00) { 194 /* Context identifier extension byte is appended. */ 195 buffer[1] |= 0x80; 196 lowpan6_header_len++; 197 } 198 #else /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */ 199 LWIP_UNUSED_ARG(lowpan6_contexts); 200 #endif /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */ 201 202 /* Determine TF field: Traffic Class, Flow Label */ 203 if (IP6H_FL(ip6hdr) == 0) { 204 /* Flow label is elided. */ 205 buffer[0] |= 0x10; 206 if (IP6H_TC(ip6hdr) == 0) { 207 /* Traffic class (ECN+DSCP) elided too. */ 208 buffer[0] |= 0x08; 209 } else { 210 /* Traffic class (ECN+DSCP) appended. */ 211 buffer[lowpan6_header_len++] = IP6H_TC(ip6hdr); 212 } 213 } else { 214 if (((IP6H_TC(ip6hdr) & 0x3f) == 0)) { 215 /* DSCP portion of Traffic Class is elided, ECN and FL are appended (3 bytes) */ 216 buffer[0] |= 0x08; 217 218 buffer[lowpan6_header_len] = IP6H_TC(ip6hdr) & 0xc0; 219 buffer[lowpan6_header_len++] |= (IP6H_FL(ip6hdr) >> 16) & 0x0f; 220 buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 8) & 0xff; 221 buffer[lowpan6_header_len++] = IP6H_FL(ip6hdr) & 0xff; 222 } else { 223 /* Traffic class and flow label are appended (4 bytes) */ 224 buffer[lowpan6_header_len++] = IP6H_TC(ip6hdr); 225 buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 16) & 0x0f; 226 buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 8) & 0xff; 227 buffer[lowpan6_header_len++] = IP6H_FL(ip6hdr) & 0xff; 228 } 229 } 230 231 /* Compress NH? 232 * Only if UDP for now. @todo support other NH compression. */ 233 if (IP6H_NEXTH(ip6hdr) == IP6_NEXTH_UDP) { 234 buffer[0] |= 0x04; 235 } else { 236 /* append nexth. */ 237 buffer[lowpan6_header_len++] = IP6H_NEXTH(ip6hdr); 238 } 239 240 /* Compress hop limit? */ 241 if (IP6H_HOPLIM(ip6hdr) == 255) { 242 buffer[0] |= 0x03; 243 } else if (IP6H_HOPLIM(ip6hdr) == 64) { 244 buffer[0] |= 0x02; 245 } else if (IP6H_HOPLIM(ip6hdr) == 1) { 246 buffer[0] |= 0x01; 247 } else { 248 /* append hop limit */ 249 buffer[lowpan6_header_len++] = IP6H_HOPLIM(ip6hdr); 250 } 251 252 /* Compress source address */ 253 if (((buffer[1] & 0x40) != 0) || 254 (ip6_addr_islinklocal(ip_2_ip6(&ip6src)))) { 255 /* Context-based or link-local source address compression. */ 256 i = lowpan6_get_address_mode(ip_2_ip6(&ip6src), src); 257 buffer[1] |= (i & 0x03) << 4; 258 if (i == 1) { 259 MEMCPY(buffer + lowpan6_header_len, inptr + 16, 8); 260 lowpan6_header_len += 8; 261 } else if (i == 2) { 262 MEMCPY(buffer + lowpan6_header_len, inptr + 22, 2); 263 lowpan6_header_len += 2; 264 } 265 } else if (ip6_addr_isany(ip_2_ip6(&ip6src))) { 266 /* Special case: mark SAC and leave SAM=0 */ 267 buffer[1] |= 0x40; 268 } else { 269 /* Append full address. */ 270 MEMCPY(buffer + lowpan6_header_len, inptr + 8, 16); 271 lowpan6_header_len += 16; 272 } 273 274 /* Compress destination address */ 275 if (ip6_addr_ismulticast(ip_2_ip6(&ip6dst))) { 276 /* @todo support stateful multicast address compression */ 277 278 buffer[1] |= 0x08; 279 280 i = lowpan6_get_address_mode_mc(ip_2_ip6(&ip6dst)); 281 buffer[1] |= i & 0x03; 282 if (i == 0) { 283 MEMCPY(buffer + lowpan6_header_len, inptr + 24, 16); 284 lowpan6_header_len += 16; 285 } else if (i == 1) { 286 buffer[lowpan6_header_len++] = inptr[25]; 287 MEMCPY(buffer + lowpan6_header_len, inptr + 35, 5); 288 lowpan6_header_len += 5; 289 } else if (i == 2) { 290 buffer[lowpan6_header_len++] = inptr[25]; 291 MEMCPY(buffer + lowpan6_header_len, inptr + 37, 3); 292 lowpan6_header_len += 3; 293 } else if (i == 3) { 294 buffer[lowpan6_header_len++] = (inptr)[39]; 295 } 296 } else if (((buffer[1] & 0x04) != 0) || 297 (ip6_addr_islinklocal(ip_2_ip6(&ip6dst)))) { 298 /* Context-based or link-local destination address compression. */ 299 i = lowpan6_get_address_mode(ip_2_ip6(&ip6dst), dst); 300 buffer[1] |= i & 0x03; 301 if (i == 1) { 302 MEMCPY(buffer + lowpan6_header_len, inptr + 32, 8); 303 lowpan6_header_len += 8; 304 } else if (i == 2) { 305 MEMCPY(buffer + lowpan6_header_len, inptr + 38, 2); 306 lowpan6_header_len += 2; 307 } 308 } else { 309 /* Append full address. */ 310 MEMCPY(buffer + lowpan6_header_len, inptr + 24, 16); 311 lowpan6_header_len += 16; 312 } 313 314 /* Move to payload. */ 315 inptr += IP6_HLEN; 316 hidden_header_len += IP6_HLEN; 317 318 #if LWIP_UDP 319 /* Compress UDP header? */ 320 if (IP6H_NEXTH(ip6hdr) == IP6_NEXTH_UDP) { 321 /* @todo support optional checksum compression */ 322 323 if (inbuf_size < IP6_HLEN + UDP_HLEN) { 324 /* input buffer too short */ 325 return ERR_VAL; 326 } 327 if (outbuf_size < (size_t)(hidden_header_len + 7)) { 328 /* output buffer too short for worst case */ 329 return ERR_MEM; 330 } 331 332 buffer[lowpan6_header_len] = 0xf0; 333 334 /* determine port compression mode. */ 335 if ((inptr[0] == 0xf0) && ((inptr[1] & 0xf0) == 0xb0) && 336 (inptr[2] == 0xf0) && ((inptr[3] & 0xf0) == 0xb0)) { 337 /* Compress source and dest ports. */ 338 buffer[lowpan6_header_len++] |= 0x03; 339 buffer[lowpan6_header_len++] = ((inptr[1] & 0x0f) << 4) | (inptr[3] & 0x0f); 340 } else if (inptr[0] == 0xf0) { 341 /* Compress source port. */ 342 buffer[lowpan6_header_len++] |= 0x02; 343 buffer[lowpan6_header_len++] = inptr[1]; 344 buffer[lowpan6_header_len++] = inptr[2]; 345 buffer[lowpan6_header_len++] = inptr[3]; 346 } else if (inptr[2] == 0xf0) { 347 /* Compress dest port. */ 348 buffer[lowpan6_header_len++] |= 0x01; 349 buffer[lowpan6_header_len++] = inptr[0]; 350 buffer[lowpan6_header_len++] = inptr[1]; 351 buffer[lowpan6_header_len++] = inptr[3]; 352 } else { 353 /* append full ports. */ 354 lowpan6_header_len++; 355 buffer[lowpan6_header_len++] = inptr[0]; 356 buffer[lowpan6_header_len++] = inptr[1]; 357 buffer[lowpan6_header_len++] = inptr[2]; 358 buffer[lowpan6_header_len++] = inptr[3]; 359 } 360 361 /* elide length and copy checksum */ 362 buffer[lowpan6_header_len++] = inptr[6]; 363 buffer[lowpan6_header_len++] = inptr[7]; 364 365 hidden_header_len += UDP_HLEN; 366 } 367 #endif /* LWIP_UDP */ 368 369 *lowpan6_header_len_out = lowpan6_header_len; 370 *hidden_header_len_out = hidden_header_len; 371 372 return ERR_OK; 373 } 374 375 /** Decompress IPv6 and UDP headers compressed according to RFC 6282 376 * 377 * @param lowpan6_buffer compressed headers, first byte is the dispatch byte 378 * @param lowpan6_bufsize size of lowpan6_buffer (may include data after headers) 379 * @param decomp_buffer buffer where the decompressed headers are stored 380 * @param decomp_bufsize size of decomp_buffer 381 * @param hdr_size_comp returns the size of the compressed headers (skip to get to data) 382 * @param hdr_size_decomp returns the size of the decompressed headers (IPv6 + UDP) 383 * @param datagram_size datagram size from fragments or 0 if unfragmented 384 * @param compressed_size compressed datagram size (for unfragmented rx) 385 * @param lowpan6_contexts context addresses 386 * @param src source address of the outer layer, used for address compression 387 * @param dest destination address of the outer layer, used for address compression 388 * @return ERR_OK if decompression succeeded, an error otherwise 389 */ 390 static err_t 391 lowpan6_decompress_hdr(u8_t *lowpan6_buffer, size_t lowpan6_bufsize, 392 u8_t *decomp_buffer, size_t decomp_bufsize, 393 u16_t *hdr_size_comp, u16_t *hdr_size_decomp, 394 u16_t datagram_size, u16_t compressed_size, 395 ip6_addr_t *lowpan6_contexts, 396 struct lowpan6_link_addr *src, struct lowpan6_link_addr *dest) 397 { 398 u16_t lowpan6_offset; 399 struct ip6_hdr *ip6hdr; 400 s8_t i; 401 u32_t header_temp; 402 u16_t ip6_offset = IP6_HLEN; 403 404 LWIP_ASSERT("lowpan6_buffer != NULL", lowpan6_buffer != NULL); 405 LWIP_ASSERT("decomp_buffer != NULL", decomp_buffer != NULL); 406 LWIP_ASSERT("src != NULL", src != NULL); 407 LWIP_ASSERT("dest != NULL", dest != NULL); 408 LWIP_ASSERT("hdr_size_comp != NULL", hdr_size_comp != NULL); 409 LWIP_ASSERT("dehdr_size_decompst != NULL", hdr_size_decomp != NULL); 410 411 ip6hdr = (struct ip6_hdr *)decomp_buffer; 412 if (decomp_bufsize < IP6_HLEN) { 413 return ERR_MEM; 414 } 415 416 /* output the full compressed packet, if set in @see lowpan6_opts.h */ 417 #if LWIP_LOWPAN6_IP_COMPRESSED_DEBUG 418 { 419 u16_t j; 420 LWIP_DEBUGF(LWIP_LOWPAN6_IP_COMPRESSED_DEBUG, ("lowpan6_decompress_hdr: IP6 payload (compressed): \n")); 421 for (j = 0; j < lowpan6_bufsize; j++) { 422 if ((j % 4) == 0) { 423 LWIP_DEBUGF(LWIP_LOWPAN6_IP_COMPRESSED_DEBUG, ("\n")); 424 } 425 LWIP_DEBUGF(LWIP_LOWPAN6_IP_COMPRESSED_DEBUG, ("%2X ", lowpan6_buffer[j])); 426 } 427 LWIP_DEBUGF(LWIP_LOWPAN6_IP_COMPRESSED_DEBUG, ("\np->len: %d", lowpan6_bufsize)); 428 } 429 #endif 430 431 /* offset for inline IP headers (RFC 6282 ch3)*/ 432 lowpan6_offset = 2; 433 /* if CID is set (context identifier), the context byte 434 * follows immediately after the header, so other IPHC fields are @+3 */ 435 if (lowpan6_buffer[1] & 0x80) { 436 lowpan6_offset++; 437 } 438 439 /* Set IPv6 version, traffic class and flow label. (RFC6282, ch 3.1.1.)*/ 440 if ((lowpan6_buffer[0] & 0x18) == 0x00) { 441 header_temp = ((lowpan6_buffer[lowpan6_offset+1] & 0x0f) << 16) | \ 442 (lowpan6_buffer[lowpan6_offset + 2] << 8) | lowpan6_buffer[lowpan6_offset+3]; 443 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("TF: 00, ECN: 0x%2x, Flowlabel+DSCP: 0x%8X\n", \ 444 lowpan6_buffer[lowpan6_offset],header_temp)); 445 IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset], header_temp); 446 /* increase offset, processed 4 bytes here: 447 * TF=00: ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)*/ 448 lowpan6_offset += 4; 449 } else if ((lowpan6_buffer[0] & 0x18) == 0x08) { 450 header_temp = ((lowpan6_buffer[lowpan6_offset] & 0x0f) << 16) | (lowpan6_buffer[lowpan6_offset + 1] << 8) | lowpan6_buffer[lowpan6_offset+2]; 451 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("TF: 01, ECN: 0x%2x, Flowlabel: 0x%2X, DSCP ignored\n", \ 452 lowpan6_buffer[lowpan6_offset] & 0xc0,header_temp)); 453 IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset] & 0xc0, header_temp); 454 /* increase offset, processed 3 bytes here: 455 * TF=01: ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided.*/ 456 lowpan6_offset += 3; 457 } else if ((lowpan6_buffer[0] & 0x18) == 0x10) { 458 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("TF: 10, DCSP+ECN: 0x%2x, Flowlabel ignored\n", lowpan6_buffer[lowpan6_offset])); 459 IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset],0); 460 /* increase offset, processed 1 byte here: 461 * ECN + DSCP (1 byte), Flow Label is elided.*/ 462 lowpan6_offset += 1; 463 } else if ((lowpan6_buffer[0] & 0x18) == 0x18) { 464 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("TF: 11, DCSP/ECN & Flowlabel ignored\n")); 465 /* don't increase offset, no bytes processed here */ 466 IP6H_VTCFL_SET(ip6hdr, 6, 0, 0); 467 } 468 469 /* Set Next Header (NH) */ 470 if ((lowpan6_buffer[0] & 0x04) == 0x00) { 471 /* 0: full next header byte carried inline (increase offset)*/ 472 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("NH: 0x%2X\n", lowpan6_buffer[lowpan6_offset+1])); 473 IP6H_NEXTH_SET(ip6hdr, lowpan6_buffer[lowpan6_offset++]); 474 } else { 475 /* 1: NH compression, LOWPAN_NHC (RFC6282, ch 4.1) */ 476 /* We should fill this later with NHC decoding */ 477 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("NH: skipped, later done with NHC\n")); 478 IP6H_NEXTH_SET(ip6hdr, 0); 479 } 480 481 /* Set Hop Limit, either carried inline or 3 different hops (1,64,255) */ 482 if ((lowpan6_buffer[0] & 0x03) == 0x00) { 483 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Hops: full value: %d\n", lowpan6_buffer[lowpan6_offset+1])); 484 IP6H_HOPLIM_SET(ip6hdr, lowpan6_buffer[lowpan6_offset++]); 485 } else if ((lowpan6_buffer[0] & 0x03) == 0x01) { 486 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Hops: compressed: 1\n")); 487 IP6H_HOPLIM_SET(ip6hdr, 1); 488 } else if ((lowpan6_buffer[0] & 0x03) == 0x02) { 489 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Hops: compressed: 64\n")); 490 IP6H_HOPLIM_SET(ip6hdr, 64); 491 } else if ((lowpan6_buffer[0] & 0x03) == 0x03) { 492 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Hops: compressed: 255\n")); 493 IP6H_HOPLIM_SET(ip6hdr, 255); 494 } 495 496 /* Source address decoding. */ 497 if ((lowpan6_buffer[1] & 0x40) == 0x00) { 498 /* Source address compression (SAC) = 0 -> stateless compression */ 499 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAC == 0, no context byte\n")); 500 /* Stateless compression */ 501 if ((lowpan6_buffer[1] & 0x30) == 0x00) { 502 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 00, no src compression, fetching 128bits inline\n")); 503 /* copy full address, increase offset by 16 Bytes */ 504 MEMCPY(&ip6hdr->src.addr[0], lowpan6_buffer + lowpan6_offset, 16); 505 lowpan6_offset += 16; 506 } else if ((lowpan6_buffer[1] & 0x30) == 0x10) { 507 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 01, src compression, 64bits inline\n")); 508 /* set 64 bits to link local */ 509 ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL); 510 ip6hdr->src.addr[1] = 0; 511 /* copy 8 Bytes, increase offset */ 512 MEMCPY(&ip6hdr->src.addr[2], lowpan6_buffer + lowpan6_offset, 8); 513 lowpan6_offset += 8; 514 } else if ((lowpan6_buffer[1] & 0x30) == 0x20) { 515 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 10, src compression, 16bits inline\n")); 516 /* set 96 bits to link local */ 517 ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL); 518 ip6hdr->src.addr[1] = 0; 519 ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL); 520 /* extract remaining 16bits from inline bytes, increase offset */ 521 ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | 522 lowpan6_buffer[lowpan6_offset + 1]); 523 lowpan6_offset += 2; 524 } else if ((lowpan6_buffer[1] & 0x30) == 0x30) { 525 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 11, src compression, 0bits inline, using other headers\n")); 526 /* no information avalaible, using other layers, see RFC6282 ch 3.2.2 */ 527 ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL); 528 ip6hdr->src.addr[1] = 0; 529 if (src->addr_len == 2) { 530 ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL); 531 ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (src->addr[0] << 8) | src->addr[1]); 532 } else if (src->addr_len == 8) { 533 ip6hdr->src.addr[2] = lwip_htonl(((src->addr[0] ^ 2) << 24) | (src->addr[1] << 16) | 534 (src->addr[2] << 8) | src->addr[3]); 535 ip6hdr->src.addr[3] = lwip_htonl((src->addr[4] << 24) | (src->addr[5] << 16) | 536 (src->addr[6] << 8) | src->addr[7]); 537 } else { 538 /* invalid source address length */ 539 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Invalid source address length\n")); 540 return ERR_VAL; 541 } 542 } 543 } else { 544 /* Source address compression (SAC) = 1 -> stateful/context-based compression */ 545 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAC == 1, additional context byte\n")); 546 if ((lowpan6_buffer[1] & 0x30) == 0x00) { 547 /* SAM=00, address=> :: (ANY) */ 548 ip6hdr->src.addr[0] = 0; 549 ip6hdr->src.addr[1] = 0; 550 ip6hdr->src.addr[2] = 0; 551 ip6hdr->src.addr[3] = 0; 552 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 00, context compression, ANY (::)\n")); 553 } else { 554 /* Set prefix from context info */ 555 if (lowpan6_buffer[1] & 0x80) { 556 i = (lowpan6_buffer[2] >> 4) & 0x0f; 557 } else { 558 i = 0; 559 } 560 if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) { 561 /* Error */ 562 return ERR_VAL; 563 } 564 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0 565 ip6hdr->src.addr[0] = lowpan6_contexts[i].addr[0]; 566 ip6hdr->src.addr[1] = lowpan6_contexts[i].addr[1]; 567 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == xx, context compression found @%d: %8X, %8X\n", (int)i, ip6hdr->src.addr[0], ip6hdr->src.addr[1])); 568 #else 569 LWIP_UNUSED_ARG(lowpan6_contexts); 570 #endif 571 } 572 573 /* determine further address bits */ 574 if ((lowpan6_buffer[1] & 0x30) == 0x10) { 575 /* SAM=01, load additional 64bits */ 576 MEMCPY(&ip6hdr->src.addr[2], lowpan6_buffer + lowpan6_offset, 8); 577 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 01, context compression, 64bits inline\n")); 578 lowpan6_offset += 8; 579 } else if ((lowpan6_buffer[1] & 0x30) == 0x20) { 580 /* SAM=01, load additional 16bits */ 581 ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL); 582 ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | lowpan6_buffer[lowpan6_offset + 1]); 583 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 10, context compression, 16bits inline\n")); 584 lowpan6_offset += 2; 585 } else if ((lowpan6_buffer[1] & 0x30) == 0x30) { 586 /* SAM=11, address is fully elided, load from other layers */ 587 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 11, context compression, 0bits inline, using other headers\n")); 588 if (src->addr_len == 2) { 589 ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL); 590 ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (src->addr[0] << 8) | src->addr[1]); 591 } else if (src->addr_len == 8) { 592 ip6hdr->src.addr[2] = lwip_htonl(((src->addr[0] ^ 2) << 24) | (src->addr[1] << 16) | (src->addr[2] << 8) | src->addr[3]); 593 ip6hdr->src.addr[3] = lwip_htonl((src->addr[4] << 24) | (src->addr[5] << 16) | (src->addr[6] << 8) | src->addr[7]); 594 } else { 595 /* invalid source address length */ 596 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Invalid source address length\n")); 597 return ERR_VAL; 598 } 599 } 600 } 601 602 /* Destination address decoding. */ 603 if (lowpan6_buffer[1] & 0x08) { 604 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("M=1: multicast\n")); 605 /* Multicast destination */ 606 if (lowpan6_buffer[1] & 0x04) { 607 LWIP_DEBUGF(LWIP_DBG_ON,("DAC == 1, context multicast: unsupported!!!\n")); 608 /* @todo support stateful multicast addressing */ 609 return ERR_VAL; 610 } 611 612 if ((lowpan6_buffer[1] & 0x03) == 0x00) { 613 /* DAM = 00, copy full address (128bits) */ 614 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 00, no dst compression, fetching 128bits inline\n")); 615 MEMCPY(&ip6hdr->dest.addr[0], lowpan6_buffer + lowpan6_offset, 16); 616 lowpan6_offset += 16; 617 } else if ((lowpan6_buffer[1] & 0x03) == 0x01) { 618 /* DAM = 01, copy 4 bytes (32bits) */ 619 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 01, dst address form (48bits): ffXX::00XX:XXXX:XXXX\n")); 620 ip6hdr->dest.addr[0] = lwip_htonl(0xff000000UL | (lowpan6_buffer[lowpan6_offset++] << 16)); 621 ip6hdr->dest.addr[1] = 0; 622 ip6hdr->dest.addr[2] = lwip_htonl(lowpan6_buffer[lowpan6_offset++]); 623 ip6hdr->dest.addr[3] = lwip_htonl((lowpan6_buffer[lowpan6_offset] << 24) | (lowpan6_buffer[lowpan6_offset + 1] << 16) | (lowpan6_buffer[lowpan6_offset + 2] << 8) | lowpan6_buffer[lowpan6_offset + 3]); 624 lowpan6_offset += 4; 625 } else if ((lowpan6_buffer[1] & 0x03) == 0x02) { 626 /* DAM = 10, copy 3 bytes (24bits) */ 627 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 10, dst address form (32bits): ffXX::00XX:XXXX\n")); 628 ip6hdr->dest.addr[0] = lwip_htonl(0xff000000UL | (lowpan6_buffer[lowpan6_offset++] << 16)); 629 ip6hdr->dest.addr[1] = 0; 630 ip6hdr->dest.addr[2] = 0; 631 ip6hdr->dest.addr[3] = lwip_htonl((lowpan6_buffer[lowpan6_offset] << 16) | (lowpan6_buffer[lowpan6_offset + 1] << 8) | lowpan6_buffer[lowpan6_offset + 2]); 632 lowpan6_offset += 3; 633 } else if ((lowpan6_buffer[1] & 0x03) == 0x03) { 634 /* DAM = 11, copy 1 byte (8bits) */ 635 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 11, dst address form (8bits): ff02::00XX\n")); 636 ip6hdr->dest.addr[0] = PP_HTONL(0xff020000UL); 637 ip6hdr->dest.addr[1] = 0; 638 ip6hdr->dest.addr[2] = 0; 639 ip6hdr->dest.addr[3] = lwip_htonl(lowpan6_buffer[lowpan6_offset++]); 640 } 641 642 } else { 643 /* no Multicast (M=0) */ 644 if (lowpan6_buffer[1] & 0x04) { 645 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAC == 1, stateful compression\n")); 646 /* Stateful destination compression */ 647 /* Set prefix from context info */ 648 if (lowpan6_buffer[1] & 0x80) { 649 i = lowpan6_buffer[2] & 0x0f; 650 } else { 651 i = 0; 652 } 653 if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) { 654 /* Error */ 655 return ERR_VAL; 656 } 657 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0 658 ip6hdr->dest.addr[0] = lowpan6_contexts[i].addr[0]; 659 ip6hdr->dest.addr[1] = lowpan6_contexts[i].addr[1]; 660 #endif 661 } else { 662 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAC == 0, stateless compression, setting link local prefix\n")); 663 /* Link local address compression */ 664 ip6hdr->dest.addr[0] = PP_HTONL(0xfe800000UL); 665 ip6hdr->dest.addr[1] = 0; 666 } 667 668 /* M=0, DAC=0, determining destination address length via DAM=xx */ 669 if ((lowpan6_buffer[1] & 0x03) == 0x00) { 670 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 00, no dst compression, fetching 128bits inline")); 671 /* DAM=00, copy full address */ 672 MEMCPY(&ip6hdr->dest.addr[0], lowpan6_buffer + lowpan6_offset, 16); 673 lowpan6_offset += 16; 674 } else if ((lowpan6_buffer[1] & 0x03) == 0x01) { 675 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 01, dst compression, 64bits inline\n")); 676 /* DAM=01, copy 64 inline bits, increase offset */ 677 MEMCPY(&ip6hdr->dest.addr[2], lowpan6_buffer + lowpan6_offset, 8); 678 lowpan6_offset += 8; 679 } else if ((lowpan6_buffer[1] & 0x03) == 0x02) { 680 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 01, dst compression, 16bits inline\n")); 681 /* DAM=10, copy 16 inline bits, increase offset */ 682 ip6hdr->dest.addr[2] = PP_HTONL(0x000000ffUL); 683 ip6hdr->dest.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | lowpan6_buffer[lowpan6_offset + 1]); 684 lowpan6_offset += 2; 685 } else if ((lowpan6_buffer[1] & 0x03) == 0x03) { 686 /* DAM=11, no bits available, use other headers (not done here) */ 687 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG,("DAM == 01, dst compression, 0bits inline, using other headers\n")); 688 if (dest->addr_len == 2) { 689 ip6hdr->dest.addr[2] = PP_HTONL(0x000000ffUL); 690 ip6hdr->dest.addr[3] = lwip_htonl(0xfe000000UL | (dest->addr[0] << 8) | dest->addr[1]); 691 } else if (dest->addr_len == 8) { 692 ip6hdr->dest.addr[2] = lwip_htonl(((dest->addr[0] ^ 2) << 24) | (dest->addr[1] << 16) | dest->addr[2] << 8 | dest->addr[3]); 693 ip6hdr->dest.addr[3] = lwip_htonl((dest->addr[4] << 24) | (dest->addr[5] << 16) | dest->addr[6] << 8 | dest->addr[7]); 694 } else { 695 /* invalid destination address length */ 696 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Invalid destination address length\n")); 697 return ERR_VAL; 698 } 699 } 700 } 701 702 703 /* Next Header Compression (NHC) decoding? */ 704 if (lowpan6_buffer[0] & 0x04) { 705 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("NHC decoding\n")); 706 #if LWIP_UDP 707 if ((lowpan6_buffer[lowpan6_offset] & 0xf8) == 0xf0) { 708 /* NHC: UDP */ 709 struct udp_hdr *udphdr; 710 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("NHC: UDP\n")); 711 712 /* UDP compression */ 713 IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_UDP); 714 udphdr = (struct udp_hdr *)((u8_t *)decomp_buffer + ip6_offset); 715 if (decomp_bufsize < IP6_HLEN + UDP_HLEN) { 716 return ERR_MEM; 717 } 718 719 /* Checksum decompression */ 720 if (lowpan6_buffer[lowpan6_offset] & 0x04) { 721 /* @todo support checksum decompress */ 722 LWIP_DEBUGF(LWIP_DBG_ON, ("NHC: UDP chechsum decompression UNSUPPORTED\n")); 723 return ERR_VAL; 724 } 725 726 /* Decompress ports, according to RFC4944 */ 727 i = lowpan6_buffer[lowpan6_offset++] & 0x03; 728 if (i == 0) { 729 udphdr->src = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]); 730 udphdr->dest = lwip_htons(lowpan6_buffer[lowpan6_offset + 2] << 8 | lowpan6_buffer[lowpan6_offset + 3]); 731 lowpan6_offset += 4; 732 } else if (i == 0x01) { 733 udphdr->src = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]); 734 udphdr->dest = lwip_htons(0xf000 | lowpan6_buffer[lowpan6_offset + 2]); 735 lowpan6_offset += 3; 736 } else if (i == 0x02) { 737 udphdr->src = lwip_htons(0xf000 | lowpan6_buffer[lowpan6_offset]); 738 udphdr->dest = lwip_htons(lowpan6_buffer[lowpan6_offset + 1] << 8 | lowpan6_buffer[lowpan6_offset + 2]); 739 lowpan6_offset += 3; 740 } else if (i == 0x03) { 741 udphdr->src = lwip_htons(0xf0b0 | ((lowpan6_buffer[lowpan6_offset] >> 4) & 0x0f)); 742 udphdr->dest = lwip_htons(0xf0b0 | (lowpan6_buffer[lowpan6_offset] & 0x0f)); 743 lowpan6_offset += 1; 744 } 745 746 udphdr->chksum = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]); 747 lowpan6_offset += 2; 748 ip6_offset += UDP_HLEN; 749 if (datagram_size == 0) { 750 datagram_size = compressed_size - lowpan6_offset + ip6_offset; 751 } 752 udphdr->len = lwip_htons(datagram_size - IP6_HLEN); 753 754 } else 755 #endif /* LWIP_UDP */ 756 { 757 LWIP_DEBUGF(LWIP_DBG_ON,("NHC: unsupported protocol!\n")); 758 /* @todo support NHC other than UDP */ 759 return ERR_VAL; 760 } 761 } 762 if (datagram_size == 0) { 763 datagram_size = compressed_size - lowpan6_offset + ip6_offset; 764 } 765 /* Infer IPv6 payload length for header */ 766 IP6H_PLEN_SET(ip6hdr, datagram_size - IP6_HLEN); 767 768 if (lowpan6_offset > lowpan6_bufsize) { 769 /* input buffer overflow */ 770 return ERR_VAL; 771 } 772 *hdr_size_comp = lowpan6_offset; 773 *hdr_size_decomp = ip6_offset; 774 775 return ERR_OK; 776 } 777 778 struct pbuf * 779 lowpan6_decompress(struct pbuf *p, u16_t datagram_size, ip6_addr_t *lowpan6_contexts, 780 struct lowpan6_link_addr *src, struct lowpan6_link_addr *dest) 781 { 782 struct pbuf *q; 783 u16_t lowpan6_offset, ip6_offset; 784 err_t err; 785 786 #if LWIP_UDP 787 #define UDP_HLEN_ALLOC UDP_HLEN 788 #else 789 #define UDP_HLEN_ALLOC 0 790 #endif 791 792 /* Allocate a buffer for decompression. This buffer will be too big and will be 793 trimmed once the final size is known. */ 794 q = pbuf_alloc(PBUF_IP, p->len + IP6_HLEN + UDP_HLEN_ALLOC, PBUF_POOL); 795 if (q == NULL) { 796 pbuf_free(p); 797 return NULL; 798 } 799 if (q->len < IP6_HLEN + UDP_HLEN_ALLOC) { 800 /* The headers need to fit into the first pbuf */ 801 pbuf_free(p); 802 pbuf_free(q); 803 return NULL; 804 } 805 806 /* Decompress the IPv6 (and possibly UDP) header(s) into the new pbuf */ 807 err = lowpan6_decompress_hdr((u8_t *)p->payload, p->len, (u8_t *)q->payload, q->len, 808 &lowpan6_offset, &ip6_offset, datagram_size, p->tot_len, lowpan6_contexts, src, dest); 809 if (err != ERR_OK) { 810 pbuf_free(p); 811 pbuf_free(q); 812 return NULL; 813 } 814 815 /* Now we copy leftover contents from p to q, so we have all L2 and L3 headers 816 (and L4?) in a single pbuf: */ 817 818 /* Hide the compressed headers in p */ 819 pbuf_remove_header(p, lowpan6_offset); 820 /* Temporarily hide the headers in q... */ 821 pbuf_remove_header(q, ip6_offset); 822 /* ... copy the rest of p into q... */ 823 pbuf_copy(q, p); 824 /* ... and reveal the headers again... */ 825 pbuf_add_header_force(q, ip6_offset); 826 /* ... trim the pbuf to its correct size... */ 827 pbuf_realloc(q, ip6_offset + p->len); 828 /* ... and cat possibly remaining (data-only) pbufs */ 829 if (p->next != NULL) { 830 pbuf_cat(q, p->next); 831 } 832 /* the original (first) pbuf can now be freed */ 833 p->next = NULL; 834 pbuf_free(p); 835 836 /* all done */ 837 return q; 838 } 839 840 #endif /* LWIP_6LOWPAN_IPHC */ 841 #endif /* LWIP_IPV6 */ 842