diff options
Diffstat (limited to 'lwip/src/netif/lowpan6_common.c')
-rw-r--r-- | lwip/src/netif/lowpan6_common.c | 841 |
1 files changed, 841 insertions, 0 deletions
diff --git a/lwip/src/netif/lowpan6_common.c b/lwip/src/netif/lowpan6_common.c new file mode 100644 index 0000000..baea206 --- /dev/null +++ b/lwip/src/netif/lowpan6_common.c @@ -0,0 +1,841 @@ +/** + * @file + * + * Common 6LowPAN routines for IPv6. Uses ND tables for link-layer addressing. Fragments packets to 6LowPAN units. + * + * This implementation aims to conform to IEEE 802.15.4(-2015), RFC 4944 and RFC 6282. + * @todo: RFC 6775. + */ + +/* + * Copyright (c) 2015 Inico Technologies Ltd. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without modification, + * are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT + * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT + * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY + * OF SUCH DAMAGE. + * + * This file is part of the lwIP TCP/IP stack. + * + * Author: Ivan Delamer <delamer@inicotech.com> + * + * + * Please coordinate changes and requests with Ivan Delamer + * <delamer@inicotech.com> + */ + +/** + * @defgroup sixlowpan 6LoWPAN (RFC4944) + * @ingroup netifs + * 6LowPAN netif implementation + */ + +#include "netif/lowpan6_common.h" + +#if LWIP_IPV6 + +#include "lwip/ip.h" +#include "lwip/pbuf.h" +#include "lwip/ip_addr.h" +#include "lwip/netif.h" +#include "lwip/udp.h" + +#include <string.h> + +/* Determine compression mode for unicast address. */ +s8_t +lowpan6_get_address_mode(const ip6_addr_t *ip6addr, const struct lowpan6_link_addr *mac_addr) +{ + if (mac_addr->addr_len == 2) { + if ((ip6addr->addr[2] == (u32_t)PP_HTONL(0x000000ff)) && + ((ip6addr->addr[3] & PP_HTONL(0xffff0000)) == PP_NTOHL(0xfe000000))) { + if ((ip6addr->addr[3] & PP_HTONL(0x0000ffff)) == lwip_ntohl((mac_addr->addr[0] << 8) | mac_addr->addr[1])) { + return 3; + } + } + } else if (mac_addr->addr_len == 8) { + 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])) && + (ip6addr->addr[3] == lwip_ntohl((mac_addr->addr[4] << 24) | (mac_addr->addr[5] << 16) | mac_addr->addr[6] << 8 | mac_addr->addr[7]))) { + return 3; + } + } + + if ((ip6addr->addr[2] == PP_HTONL(0x000000ffUL)) && + ((ip6addr->addr[3] & PP_HTONL(0xffff0000)) == PP_NTOHL(0xfe000000UL))) { + return 2; + } + + return 1; +} + +#if LWIP_6LOWPAN_IPHC + +/* Determine compression mode for multicast address. */ +static s8_t +lowpan6_get_address_mode_mc(const ip6_addr_t *ip6addr) +{ + if ((ip6addr->addr[0] == PP_HTONL(0xff020000)) && + (ip6addr->addr[1] == 0) && + (ip6addr->addr[2] == 0) && + ((ip6addr->addr[3] & PP_HTONL(0xffffff00)) == 0)) { + return 3; + } else if (((ip6addr->addr[0] & PP_HTONL(0xff00ffff)) == PP_HTONL(0xff000000)) && + (ip6addr->addr[1] == 0)) { + if ((ip6addr->addr[2] == 0) && + ((ip6addr->addr[3] & PP_HTONL(0xff000000)) == 0)) { + return 2; + } else if ((ip6addr->addr[2] & PP_HTONL(0xffffff00)) == 0) { + return 1; + } + } + + return 0; +} + +#if LWIP_6LOWPAN_NUM_CONTEXTS > 0 +static s8_t +lowpan6_context_lookup(const ip6_addr_t *lowpan6_contexts, const ip6_addr_t *ip6addr) +{ + s8_t i; + + for (i = 0; i < LWIP_6LOWPAN_NUM_CONTEXTS; i++) { + if (ip6_addr_netcmp(&lowpan6_contexts[i], ip6addr)) { + return i; + } + } + return -1; +} +#endif /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */ + +/* + * Compress IPv6 and/or UDP headers. + * */ +err_t +lowpan6_compress_headers(struct netif *netif, u8_t *inbuf, size_t inbuf_size, u8_t *outbuf, size_t outbuf_size, + u8_t *lowpan6_header_len_out, u8_t *hidden_header_len_out, ip6_addr_t *lowpan6_contexts, + const struct lowpan6_link_addr *src, const struct lowpan6_link_addr *dst) +{ + u8_t *buffer, *inptr; + u8_t lowpan6_header_len; + u8_t hidden_header_len = 0; + s8_t i; + struct ip6_hdr *ip6hdr; + ip_addr_t ip6src, ip6dst; + + LWIP_ASSERT("netif != NULL", netif != NULL); + LWIP_ASSERT("inbuf != NULL", inbuf != NULL); + LWIP_ASSERT("outbuf != NULL", outbuf != NULL); + LWIP_ASSERT("lowpan6_header_len_out != NULL", lowpan6_header_len_out != NULL); + LWIP_ASSERT("hidden_header_len_out != NULL", hidden_header_len_out != NULL); + + /* Perform 6LowPAN IPv6 header compression according to RFC 6282 */ + buffer = outbuf; + inptr = inbuf; + + if (inbuf_size < IP6_HLEN) { + /* input buffer too short */ + return ERR_VAL; + } + if (outbuf_size < IP6_HLEN) { + /* output buffer too short for worst case */ + return ERR_MEM; + } + + /* Point to ip6 header and align copies of src/dest addresses. */ + ip6hdr = (struct ip6_hdr *)inptr; + ip_addr_copy_from_ip6_packed(ip6dst, ip6hdr->dest); + ip6_addr_assign_zone(ip_2_ip6(&ip6dst), IP6_UNKNOWN, netif); + ip_addr_copy_from_ip6_packed(ip6src, ip6hdr->src); + ip6_addr_assign_zone(ip_2_ip6(&ip6src), IP6_UNKNOWN, netif); + + /* Basic length of 6LowPAN header, set dispatch and clear fields. */ + lowpan6_header_len = 2; + buffer[0] = 0x60; + buffer[1] = 0; + + /* Determine whether there will be a Context Identifier Extension byte or not. + * If so, set it already. */ +#if LWIP_6LOWPAN_NUM_CONTEXTS > 0 + buffer[2] = 0; + + i = lowpan6_context_lookup(lowpan6_contexts, ip_2_ip6(&ip6src)); + if (i >= 0) { + /* Stateful source address compression. */ + buffer[1] |= 0x40; + buffer[2] |= (i & 0x0f) << 4; + } + + i = lowpan6_context_lookup(lowpan6_contexts, ip_2_ip6(&ip6dst)); + if (i >= 0) { + /* Stateful destination address compression. */ + buffer[1] |= 0x04; + buffer[2] |= i & 0x0f; + } + + if (buffer[2] != 0x00) { + /* Context identifier extension byte is appended. */ + buffer[1] |= 0x80; + lowpan6_header_len++; + } +#else /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */ + LWIP_UNUSED_ARG(lowpan6_contexts); +#endif /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */ + + /* Determine TF field: Traffic Class, Flow Label */ + if (IP6H_FL(ip6hdr) == 0) { + /* Flow label is elided. */ + buffer[0] |= 0x10; + if (IP6H_TC(ip6hdr) == 0) { + /* Traffic class (ECN+DSCP) elided too. */ + buffer[0] |= 0x08; + } else { + /* Traffic class (ECN+DSCP) appended. */ + buffer[lowpan6_header_len++] = IP6H_TC(ip6hdr); + } + } else { + if (((IP6H_TC(ip6hdr) & 0x3f) == 0)) { + /* DSCP portion of Traffic Class is elided, ECN and FL are appended (3 bytes) */ + buffer[0] |= 0x08; + + buffer[lowpan6_header_len] = IP6H_TC(ip6hdr) & 0xc0; + buffer[lowpan6_header_len++] |= (IP6H_FL(ip6hdr) >> 16) & 0x0f; + buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 8) & 0xff; + buffer[lowpan6_header_len++] = IP6H_FL(ip6hdr) & 0xff; + } else { + /* Traffic class and flow label are appended (4 bytes) */ + buffer[lowpan6_header_len++] = IP6H_TC(ip6hdr); + buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 16) & 0x0f; + buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 8) & 0xff; + buffer[lowpan6_header_len++] = IP6H_FL(ip6hdr) & 0xff; + } + } + + /* Compress NH? + * Only if UDP for now. @todo support other NH compression. */ + if (IP6H_NEXTH(ip6hdr) == IP6_NEXTH_UDP) { + buffer[0] |= 0x04; + } else { + /* append nexth. */ + buffer[lowpan6_header_len++] = IP6H_NEXTH(ip6hdr); + } + + /* Compress hop limit? */ + if (IP6H_HOPLIM(ip6hdr) == 255) { + buffer[0] |= 0x03; + } else if (IP6H_HOPLIM(ip6hdr) == 64) { + buffer[0] |= 0x02; + } else if (IP6H_HOPLIM(ip6hdr) == 1) { + buffer[0] |= 0x01; + } else { + /* append hop limit */ + buffer[lowpan6_header_len++] = IP6H_HOPLIM(ip6hdr); + } + + /* Compress source address */ + if (((buffer[1] & 0x40) != 0) || + (ip6_addr_islinklocal(ip_2_ip6(&ip6src)))) { + /* Context-based or link-local source address compression. */ + i = lowpan6_get_address_mode(ip_2_ip6(&ip6src), src); + buffer[1] |= (i & 0x03) << 4; + if (i == 1) { + MEMCPY(buffer + lowpan6_header_len, inptr + 16, 8); + lowpan6_header_len += 8; + } else if (i == 2) { + MEMCPY(buffer + lowpan6_header_len, inptr + 22, 2); + lowpan6_header_len += 2; + } + } else if (ip6_addr_isany(ip_2_ip6(&ip6src))) { + /* Special case: mark SAC and leave SAM=0 */ + buffer[1] |= 0x40; + } else { + /* Append full address. */ + MEMCPY(buffer + lowpan6_header_len, inptr + 8, 16); + lowpan6_header_len += 16; + } + + /* Compress destination address */ + if (ip6_addr_ismulticast(ip_2_ip6(&ip6dst))) { + /* @todo support stateful multicast address compression */ + + buffer[1] |= 0x08; + + i = lowpan6_get_address_mode_mc(ip_2_ip6(&ip6dst)); + buffer[1] |= i & 0x03; + if (i == 0) { + MEMCPY(buffer + lowpan6_header_len, inptr + 24, 16); + lowpan6_header_len += 16; + } else if (i == 1) { + buffer[lowpan6_header_len++] = inptr[25]; + MEMCPY(buffer + lowpan6_header_len, inptr + 35, 5); + lowpan6_header_len += 5; + } else if (i == 2) { + buffer[lowpan6_header_len++] = inptr[25]; + MEMCPY(buffer + lowpan6_header_len, inptr + 37, 3); + lowpan6_header_len += 3; + } else if (i == 3) { + buffer[lowpan6_header_len++] = (inptr)[39]; + } + } else if (((buffer[1] & 0x04) != 0) || + (ip6_addr_islinklocal(ip_2_ip6(&ip6dst)))) { + /* Context-based or link-local destination address compression. */ + i = lowpan6_get_address_mode(ip_2_ip6(&ip6dst), dst); + buffer[1] |= i & 0x03; + if (i == 1) { + MEMCPY(buffer + lowpan6_header_len, inptr + 32, 8); + lowpan6_header_len += 8; + } else if (i == 2) { + MEMCPY(buffer + lowpan6_header_len, inptr + 38, 2); + lowpan6_header_len += 2; + } + } else { + /* Append full address. */ + MEMCPY(buffer + lowpan6_header_len, inptr + 24, 16); + lowpan6_header_len += 16; + } + + /* Move to payload. */ + inptr += IP6_HLEN; + hidden_header_len += IP6_HLEN; + +#if LWIP_UDP + /* Compress UDP header? */ + if (IP6H_NEXTH(ip6hdr) == IP6_NEXTH_UDP) { + /* @todo support optional checksum compression */ + + if (inbuf_size < IP6_HLEN + UDP_HLEN) { + /* input buffer too short */ + return ERR_VAL; + } + if (outbuf_size < (size_t)(hidden_header_len + 7)) { + /* output buffer too short for worst case */ + return ERR_MEM; + } + + buffer[lowpan6_header_len] = 0xf0; + + /* determine port compression mode. */ + if ((inptr[0] == 0xf0) && ((inptr[1] & 0xf0) == 0xb0) && + (inptr[2] == 0xf0) && ((inptr[3] & 0xf0) == 0xb0)) { + /* Compress source and dest ports. */ + buffer[lowpan6_header_len++] |= 0x03; + buffer[lowpan6_header_len++] = ((inptr[1] & 0x0f) << 4) | (inptr[3] & 0x0f); + } else if (inptr[0] == 0xf0) { + /* Compress source port. */ + buffer[lowpan6_header_len++] |= 0x02; + buffer[lowpan6_header_len++] = inptr[1]; + buffer[lowpan6_header_len++] = inptr[2]; + buffer[lowpan6_header_len++] = inptr[3]; + } else if (inptr[2] == 0xf0) { + /* Compress dest port. */ + buffer[lowpan6_header_len++] |= 0x01; + buffer[lowpan6_header_len++] = inptr[0]; + buffer[lowpan6_header_len++] = inptr[1]; + buffer[lowpan6_header_len++] = inptr[3]; + } else { + /* append full ports. */ + lowpan6_header_len++; + buffer[lowpan6_header_len++] = inptr[0]; + buffer[lowpan6_header_len++] = inptr[1]; + buffer[lowpan6_header_len++] = inptr[2]; + buffer[lowpan6_header_len++] = inptr[3]; + } + + /* elide length and copy checksum */ + buffer[lowpan6_header_len++] = inptr[6]; + buffer[lowpan6_header_len++] = inptr[7]; + + hidden_header_len += UDP_HLEN; + } +#endif /* LWIP_UDP */ + + *lowpan6_header_len_out = lowpan6_header_len; + *hidden_header_len_out = hidden_header_len; + + return ERR_OK; +} + +/** Decompress IPv6 and UDP headers compressed according to RFC 6282 + * + * @param lowpan6_buffer compressed headers, first byte is the dispatch byte + * @param lowpan6_bufsize size of lowpan6_buffer (may include data after headers) + * @param decomp_buffer buffer where the decompressed headers are stored + * @param decomp_bufsize size of decomp_buffer + * @param hdr_size_comp returns the size of the compressed headers (skip to get to data) + * @param hdr_size_decomp returns the size of the decompressed headers (IPv6 + UDP) + * @param datagram_size datagram size from fragments or 0 if unfragmented + * @param compressed_size compressed datagram size (for unfragmented rx) + * @param lowpan6_contexts context addresses + * @param src source address of the outer layer, used for address compression + * @param dest destination address of the outer layer, used for address compression + * @return ERR_OK if decompression succeeded, an error otherwise + */ +static err_t +lowpan6_decompress_hdr(u8_t *lowpan6_buffer, size_t lowpan6_bufsize, + u8_t *decomp_buffer, size_t decomp_bufsize, + u16_t *hdr_size_comp, u16_t *hdr_size_decomp, + u16_t datagram_size, u16_t compressed_size, + ip6_addr_t *lowpan6_contexts, + struct lowpan6_link_addr *src, struct lowpan6_link_addr *dest) +{ + u16_t lowpan6_offset; + struct ip6_hdr *ip6hdr; + s8_t i; + u32_t header_temp; + u16_t ip6_offset = IP6_HLEN; + + LWIP_ASSERT("lowpan6_buffer != NULL", lowpan6_buffer != NULL); + LWIP_ASSERT("decomp_buffer != NULL", decomp_buffer != NULL); + LWIP_ASSERT("src != NULL", src != NULL); + LWIP_ASSERT("dest != NULL", dest != NULL); + LWIP_ASSERT("hdr_size_comp != NULL", hdr_size_comp != NULL); + LWIP_ASSERT("dehdr_size_decompst != NULL", hdr_size_decomp != NULL); + + ip6hdr = (struct ip6_hdr *)decomp_buffer; + if (decomp_bufsize < IP6_HLEN) { + return ERR_MEM; + } + + /* output the full compressed packet, if set in @see lowpan6_opts.h */ +#if LWIP_LOWPAN6_IP_COMPRESSED_DEBUG + { + u16_t j; + LWIP_DEBUGF(LWIP_LOWPAN6_IP_COMPRESSED_DEBUG, ("lowpan6_decompress_hdr: IP6 payload (compressed): \n")); + for (j = 0; j < lowpan6_bufsize; j++) { + if ((j % 4) == 0) { + LWIP_DEBUGF(LWIP_LOWPAN6_IP_COMPRESSED_DEBUG, ("\n")); + } + LWIP_DEBUGF(LWIP_LOWPAN6_IP_COMPRESSED_DEBUG, ("%2X ", lowpan6_buffer[j])); + } + LWIP_DEBUGF(LWIP_LOWPAN6_IP_COMPRESSED_DEBUG, ("\np->len: %d", lowpan6_bufsize)); + } +#endif + + /* offset for inline IP headers (RFC 6282 ch3)*/ + lowpan6_offset = 2; + /* if CID is set (context identifier), the context byte + * follows immediately after the header, so other IPHC fields are @+3 */ + if (lowpan6_buffer[1] & 0x80) { + lowpan6_offset++; + } + + /* Set IPv6 version, traffic class and flow label. (RFC6282, ch 3.1.1.)*/ + if ((lowpan6_buffer[0] & 0x18) == 0x00) { + header_temp = ((lowpan6_buffer[lowpan6_offset+1] & 0x0f) << 16) | \ + (lowpan6_buffer[lowpan6_offset + 2] << 8) | lowpan6_buffer[lowpan6_offset+3]; + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("TF: 00, ECN: 0x%2x, Flowlabel+DSCP: 0x%8X\n", \ + lowpan6_buffer[lowpan6_offset],header_temp)); + IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset], header_temp); + /* increase offset, processed 4 bytes here: + * TF=00: ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)*/ + lowpan6_offset += 4; + } else if ((lowpan6_buffer[0] & 0x18) == 0x08) { + header_temp = ((lowpan6_buffer[lowpan6_offset] & 0x0f) << 16) | (lowpan6_buffer[lowpan6_offset + 1] << 8) | lowpan6_buffer[lowpan6_offset+2]; + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("TF: 01, ECN: 0x%2x, Flowlabel: 0x%2X, DSCP ignored\n", \ + lowpan6_buffer[lowpan6_offset] & 0xc0,header_temp)); + IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset] & 0xc0, header_temp); + /* increase offset, processed 3 bytes here: + * TF=01: ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided.*/ + lowpan6_offset += 3; + } else if ((lowpan6_buffer[0] & 0x18) == 0x10) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("TF: 10, DCSP+ECN: 0x%2x, Flowlabel ignored\n", lowpan6_buffer[lowpan6_offset])); + IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset],0); + /* increase offset, processed 1 byte here: + * ECN + DSCP (1 byte), Flow Label is elided.*/ + lowpan6_offset += 1; + } else if ((lowpan6_buffer[0] & 0x18) == 0x18) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("TF: 11, DCSP/ECN & Flowlabel ignored\n")); + /* don't increase offset, no bytes processed here */ + IP6H_VTCFL_SET(ip6hdr, 6, 0, 0); + } + + /* Set Next Header (NH) */ + if ((lowpan6_buffer[0] & 0x04) == 0x00) { + /* 0: full next header byte carried inline (increase offset)*/ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("NH: 0x%2X\n", lowpan6_buffer[lowpan6_offset+1])); + IP6H_NEXTH_SET(ip6hdr, lowpan6_buffer[lowpan6_offset++]); + } else { + /* 1: NH compression, LOWPAN_NHC (RFC6282, ch 4.1) */ + /* We should fill this later with NHC decoding */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("NH: skipped, later done with NHC\n")); + IP6H_NEXTH_SET(ip6hdr, 0); + } + + /* Set Hop Limit, either carried inline or 3 different hops (1,64,255) */ + if ((lowpan6_buffer[0] & 0x03) == 0x00) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Hops: full value: %d\n", lowpan6_buffer[lowpan6_offset+1])); + IP6H_HOPLIM_SET(ip6hdr, lowpan6_buffer[lowpan6_offset++]); + } else if ((lowpan6_buffer[0] & 0x03) == 0x01) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Hops: compressed: 1\n")); + IP6H_HOPLIM_SET(ip6hdr, 1); + } else if ((lowpan6_buffer[0] & 0x03) == 0x02) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Hops: compressed: 64\n")); + IP6H_HOPLIM_SET(ip6hdr, 64); + } else if ((lowpan6_buffer[0] & 0x03) == 0x03) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Hops: compressed: 255\n")); + IP6H_HOPLIM_SET(ip6hdr, 255); + } + + /* Source address decoding. */ + if ((lowpan6_buffer[1] & 0x40) == 0x00) { + /* Source address compression (SAC) = 0 -> stateless compression */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAC == 0, no context byte\n")); + /* Stateless compression */ + if ((lowpan6_buffer[1] & 0x30) == 0x00) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 00, no src compression, fetching 128bits inline\n")); + /* copy full address, increase offset by 16 Bytes */ + MEMCPY(&ip6hdr->src.addr[0], lowpan6_buffer + lowpan6_offset, 16); + lowpan6_offset += 16; + } else if ((lowpan6_buffer[1] & 0x30) == 0x10) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 01, src compression, 64bits inline\n")); + /* set 64 bits to link local */ + ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL); + ip6hdr->src.addr[1] = 0; + /* copy 8 Bytes, increase offset */ + MEMCPY(&ip6hdr->src.addr[2], lowpan6_buffer + lowpan6_offset, 8); + lowpan6_offset += 8; + } else if ((lowpan6_buffer[1] & 0x30) == 0x20) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 10, src compression, 16bits inline\n")); + /* set 96 bits to link local */ + ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL); + ip6hdr->src.addr[1] = 0; + ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL); + /* extract remaining 16bits from inline bytes, increase offset */ + ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | + lowpan6_buffer[lowpan6_offset + 1]); + lowpan6_offset += 2; + } else if ((lowpan6_buffer[1] & 0x30) == 0x30) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 11, src compression, 0bits inline, using other headers\n")); + /* no information avalaible, using other layers, see RFC6282 ch 3.2.2 */ + ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL); + ip6hdr->src.addr[1] = 0; + if (src->addr_len == 2) { + ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL); + ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (src->addr[0] << 8) | src->addr[1]); + } else if (src->addr_len == 8) { + ip6hdr->src.addr[2] = lwip_htonl(((src->addr[0] ^ 2) << 24) | (src->addr[1] << 16) | + (src->addr[2] << 8) | src->addr[3]); + ip6hdr->src.addr[3] = lwip_htonl((src->addr[4] << 24) | (src->addr[5] << 16) | + (src->addr[6] << 8) | src->addr[7]); + } else { + /* invalid source address length */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Invalid source address length\n")); + return ERR_VAL; + } + } + } else { + /* Source address compression (SAC) = 1 -> stateful/context-based compression */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAC == 1, additional context byte\n")); + if ((lowpan6_buffer[1] & 0x30) == 0x00) { + /* SAM=00, address=> :: (ANY) */ + ip6hdr->src.addr[0] = 0; + ip6hdr->src.addr[1] = 0; + ip6hdr->src.addr[2] = 0; + ip6hdr->src.addr[3] = 0; + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 00, context compression, ANY (::)\n")); + } else { + /* Set prefix from context info */ + if (lowpan6_buffer[1] & 0x80) { + i = (lowpan6_buffer[2] >> 4) & 0x0f; + } else { + i = 0; + } + if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) { + /* Error */ + return ERR_VAL; + } +#if LWIP_6LOWPAN_NUM_CONTEXTS > 0 + ip6hdr->src.addr[0] = lowpan6_contexts[i].addr[0]; + ip6hdr->src.addr[1] = lowpan6_contexts[i].addr[1]; + 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])); +#else + LWIP_UNUSED_ARG(lowpan6_contexts); +#endif + } + + /* determine further address bits */ + if ((lowpan6_buffer[1] & 0x30) == 0x10) { + /* SAM=01, load additional 64bits */ + MEMCPY(&ip6hdr->src.addr[2], lowpan6_buffer + lowpan6_offset, 8); + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 01, context compression, 64bits inline\n")); + lowpan6_offset += 8; + } else if ((lowpan6_buffer[1] & 0x30) == 0x20) { + /* SAM=01, load additional 16bits */ + ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL); + ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | lowpan6_buffer[lowpan6_offset + 1]); + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 10, context compression, 16bits inline\n")); + lowpan6_offset += 2; + } else if ((lowpan6_buffer[1] & 0x30) == 0x30) { + /* SAM=11, address is fully elided, load from other layers */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("SAM == 11, context compression, 0bits inline, using other headers\n")); + if (src->addr_len == 2) { + ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL); + ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (src->addr[0] << 8) | src->addr[1]); + } else if (src->addr_len == 8) { + ip6hdr->src.addr[2] = lwip_htonl(((src->addr[0] ^ 2) << 24) | (src->addr[1] << 16) | (src->addr[2] << 8) | src->addr[3]); + ip6hdr->src.addr[3] = lwip_htonl((src->addr[4] << 24) | (src->addr[5] << 16) | (src->addr[6] << 8) | src->addr[7]); + } else { + /* invalid source address length */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Invalid source address length\n")); + return ERR_VAL; + } + } + } + + /* Destination address decoding. */ + if (lowpan6_buffer[1] & 0x08) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("M=1: multicast\n")); + /* Multicast destination */ + if (lowpan6_buffer[1] & 0x04) { + LWIP_DEBUGF(LWIP_DBG_ON,("DAC == 1, context multicast: unsupported!!!\n")); + /* @todo support stateful multicast addressing */ + return ERR_VAL; + } + + if ((lowpan6_buffer[1] & 0x03) == 0x00) { + /* DAM = 00, copy full address (128bits) */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 00, no dst compression, fetching 128bits inline\n")); + MEMCPY(&ip6hdr->dest.addr[0], lowpan6_buffer + lowpan6_offset, 16); + lowpan6_offset += 16; + } else if ((lowpan6_buffer[1] & 0x03) == 0x01) { + /* DAM = 01, copy 4 bytes (32bits) */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 01, dst address form (48bits): ffXX::00XX:XXXX:XXXX\n")); + ip6hdr->dest.addr[0] = lwip_htonl(0xff000000UL | (lowpan6_buffer[lowpan6_offset++] << 16)); + ip6hdr->dest.addr[1] = 0; + ip6hdr->dest.addr[2] = lwip_htonl(lowpan6_buffer[lowpan6_offset++]); + 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]); + lowpan6_offset += 4; + } else if ((lowpan6_buffer[1] & 0x03) == 0x02) { + /* DAM = 10, copy 3 bytes (24bits) */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 10, dst address form (32bits): ffXX::00XX:XXXX\n")); + ip6hdr->dest.addr[0] = lwip_htonl(0xff000000UL | (lowpan6_buffer[lowpan6_offset++] << 16)); + ip6hdr->dest.addr[1] = 0; + ip6hdr->dest.addr[2] = 0; + ip6hdr->dest.addr[3] = lwip_htonl((lowpan6_buffer[lowpan6_offset] << 16) | (lowpan6_buffer[lowpan6_offset + 1] << 8) | lowpan6_buffer[lowpan6_offset + 2]); + lowpan6_offset += 3; + } else if ((lowpan6_buffer[1] & 0x03) == 0x03) { + /* DAM = 11, copy 1 byte (8bits) */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 11, dst address form (8bits): ff02::00XX\n")); + ip6hdr->dest.addr[0] = PP_HTONL(0xff020000UL); + ip6hdr->dest.addr[1] = 0; + ip6hdr->dest.addr[2] = 0; + ip6hdr->dest.addr[3] = lwip_htonl(lowpan6_buffer[lowpan6_offset++]); + } + + } else { + /* no Multicast (M=0) */ + if (lowpan6_buffer[1] & 0x04) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAC == 1, stateful compression\n")); + /* Stateful destination compression */ + /* Set prefix from context info */ + if (lowpan6_buffer[1] & 0x80) { + i = lowpan6_buffer[2] & 0x0f; + } else { + i = 0; + } + if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) { + /* Error */ + return ERR_VAL; + } +#if LWIP_6LOWPAN_NUM_CONTEXTS > 0 + ip6hdr->dest.addr[0] = lowpan6_contexts[i].addr[0]; + ip6hdr->dest.addr[1] = lowpan6_contexts[i].addr[1]; +#endif + } else { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAC == 0, stateless compression, setting link local prefix\n")); + /* Link local address compression */ + ip6hdr->dest.addr[0] = PP_HTONL(0xfe800000UL); + ip6hdr->dest.addr[1] = 0; + } + + /* M=0, DAC=0, determining destination address length via DAM=xx */ + if ((lowpan6_buffer[1] & 0x03) == 0x00) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 00, no dst compression, fetching 128bits inline")); + /* DAM=00, copy full address */ + MEMCPY(&ip6hdr->dest.addr[0], lowpan6_buffer + lowpan6_offset, 16); + lowpan6_offset += 16; + } else if ((lowpan6_buffer[1] & 0x03) == 0x01) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 01, dst compression, 64bits inline\n")); + /* DAM=01, copy 64 inline bits, increase offset */ + MEMCPY(&ip6hdr->dest.addr[2], lowpan6_buffer + lowpan6_offset, 8); + lowpan6_offset += 8; + } else if ((lowpan6_buffer[1] & 0x03) == 0x02) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("DAM == 01, dst compression, 16bits inline\n")); + /* DAM=10, copy 16 inline bits, increase offset */ + ip6hdr->dest.addr[2] = PP_HTONL(0x000000ffUL); + ip6hdr->dest.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | lowpan6_buffer[lowpan6_offset + 1]); + lowpan6_offset += 2; + } else if ((lowpan6_buffer[1] & 0x03) == 0x03) { + /* DAM=11, no bits available, use other headers (not done here) */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG,("DAM == 01, dst compression, 0bits inline, using other headers\n")); + if (dest->addr_len == 2) { + ip6hdr->dest.addr[2] = PP_HTONL(0x000000ffUL); + ip6hdr->dest.addr[3] = lwip_htonl(0xfe000000UL | (dest->addr[0] << 8) | dest->addr[1]); + } else if (dest->addr_len == 8) { + ip6hdr->dest.addr[2] = lwip_htonl(((dest->addr[0] ^ 2) << 24) | (dest->addr[1] << 16) | dest->addr[2] << 8 | dest->addr[3]); + ip6hdr->dest.addr[3] = lwip_htonl((dest->addr[4] << 24) | (dest->addr[5] << 16) | dest->addr[6] << 8 | dest->addr[7]); + } else { + /* invalid destination address length */ + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Invalid destination address length\n")); + return ERR_VAL; + } + } + } + + + /* Next Header Compression (NHC) decoding? */ + if (lowpan6_buffer[0] & 0x04) { + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("NHC decoding\n")); +#if LWIP_UDP + if ((lowpan6_buffer[lowpan6_offset] & 0xf8) == 0xf0) { + /* NHC: UDP */ + struct udp_hdr *udphdr; + LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("NHC: UDP\n")); + + /* UDP compression */ + IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_UDP); + udphdr = (struct udp_hdr *)((u8_t *)decomp_buffer + ip6_offset); + if (decomp_bufsize < IP6_HLEN + UDP_HLEN) { + return ERR_MEM; + } + + /* Checksum decompression */ + if (lowpan6_buffer[lowpan6_offset] & 0x04) { + /* @todo support checksum decompress */ + LWIP_DEBUGF(LWIP_DBG_ON, ("NHC: UDP chechsum decompression UNSUPPORTED\n")); + return ERR_VAL; + } + + /* Decompress ports, according to RFC4944 */ + i = lowpan6_buffer[lowpan6_offset++] & 0x03; + if (i == 0) { + udphdr->src = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]); + udphdr->dest = lwip_htons(lowpan6_buffer[lowpan6_offset + 2] << 8 | lowpan6_buffer[lowpan6_offset + 3]); + lowpan6_offset += 4; + } else if (i == 0x01) { + udphdr->src = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]); + udphdr->dest = lwip_htons(0xf000 | lowpan6_buffer[lowpan6_offset + 2]); + lowpan6_offset += 3; + } else if (i == 0x02) { + udphdr->src = lwip_htons(0xf000 | lowpan6_buffer[lowpan6_offset]); + udphdr->dest = lwip_htons(lowpan6_buffer[lowpan6_offset + 1] << 8 | lowpan6_buffer[lowpan6_offset + 2]); + lowpan6_offset += 3; + } else if (i == 0x03) { + udphdr->src = lwip_htons(0xf0b0 | ((lowpan6_buffer[lowpan6_offset] >> 4) & 0x0f)); + udphdr->dest = lwip_htons(0xf0b0 | (lowpan6_buffer[lowpan6_offset] & 0x0f)); + lowpan6_offset += 1; + } + + udphdr->chksum = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]); + lowpan6_offset += 2; + ip6_offset += UDP_HLEN; + if (datagram_size == 0) { + datagram_size = compressed_size - lowpan6_offset + ip6_offset; + } + udphdr->len = lwip_htons(datagram_size - IP6_HLEN); + + } else +#endif /* LWIP_UDP */ + { + LWIP_DEBUGF(LWIP_DBG_ON,("NHC: unsupported protocol!\n")); + /* @todo support NHC other than UDP */ + return ERR_VAL; + } + } + if (datagram_size == 0) { + datagram_size = compressed_size - lowpan6_offset + ip6_offset; + } + /* Infer IPv6 payload length for header */ + IP6H_PLEN_SET(ip6hdr, datagram_size - IP6_HLEN); + + if (lowpan6_offset > lowpan6_bufsize) { + /* input buffer overflow */ + return ERR_VAL; + } + *hdr_size_comp = lowpan6_offset; + *hdr_size_decomp = ip6_offset; + + return ERR_OK; +} + +struct pbuf * +lowpan6_decompress(struct pbuf *p, u16_t datagram_size, ip6_addr_t *lowpan6_contexts, + struct lowpan6_link_addr *src, struct lowpan6_link_addr *dest) +{ + struct pbuf *q; + u16_t lowpan6_offset, ip6_offset; + err_t err; + +#if LWIP_UDP +#define UDP_HLEN_ALLOC UDP_HLEN +#else +#define UDP_HLEN_ALLOC 0 +#endif + + /* Allocate a buffer for decompression. This buffer will be too big and will be + trimmed once the final size is known. */ + q = pbuf_alloc(PBUF_IP, p->len + IP6_HLEN + UDP_HLEN_ALLOC, PBUF_POOL); + if (q == NULL) { + pbuf_free(p); + return NULL; + } + if (q->len < IP6_HLEN + UDP_HLEN_ALLOC) { + /* The headers need to fit into the first pbuf */ + pbuf_free(p); + pbuf_free(q); + return NULL; + } + + /* Decompress the IPv6 (and possibly UDP) header(s) into the new pbuf */ + err = lowpan6_decompress_hdr((u8_t *)p->payload, p->len, (u8_t *)q->payload, q->len, + &lowpan6_offset, &ip6_offset, datagram_size, p->tot_len, lowpan6_contexts, src, dest); + if (err != ERR_OK) { + pbuf_free(p); + pbuf_free(q); + return NULL; + } + + /* Now we copy leftover contents from p to q, so we have all L2 and L3 headers + (and L4?) in a single pbuf: */ + + /* Hide the compressed headers in p */ + pbuf_remove_header(p, lowpan6_offset); + /* Temporarily hide the headers in q... */ + pbuf_remove_header(q, ip6_offset); + /* ... copy the rest of p into q... */ + pbuf_copy(q, p); + /* ... and reveal the headers again... */ + pbuf_add_header_force(q, ip6_offset); + /* ... trim the pbuf to its correct size... */ + pbuf_realloc(q, ip6_offset + p->len); + /* ... and cat possibly remaining (data-only) pbufs */ + if (p->next != NULL) { + pbuf_cat(q, p->next); + } + /* the original (first) pbuf can now be freed */ + p->next = NULL; + pbuf_free(p); + + /* all done */ + return q; +} + +#endif /* LWIP_6LOWPAN_IPHC */ +#endif /* LWIP_IPV6 */ |