/* * Copyright 2011, Siemens AG * written by Alexander Smirnov */ /* Based on patches from Jon Smirl * Copyright (c) 2011 Jon Smirl * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * */ /* Jon's code is based on 6lowpan implementation for Contiki which is: * Copyright (c) 2008, Swedish Institute of Computer Science. * 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. Neither the name of the Institute nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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. */ #include #include #include #include #include #include #include #include "nhc.h" /* Uncompress address function for source and * destination address(non-multicast). * * address_mode is sam value or dam value. */ static int uncompress_addr(struct sk_buff *skb, struct in6_addr *ipaddr, const u8 address_mode, const u8 *lladdr, const u8 addr_type, const u8 addr_len) { bool fail; switch (address_mode) { case LOWPAN_IPHC_ADDR_00: /* for global link addresses */ fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16); break; case LOWPAN_IPHC_ADDR_01: /* fe:80::XXXX:XXXX:XXXX:XXXX */ ipaddr->s6_addr[0] = 0xFE; ipaddr->s6_addr[1] = 0x80; fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8); break; case LOWPAN_IPHC_ADDR_02: /* fe:80::ff:fe00:XXXX */ ipaddr->s6_addr[0] = 0xFE; ipaddr->s6_addr[1] = 0x80; ipaddr->s6_addr[11] = 0xFF; ipaddr->s6_addr[12] = 0xFE; fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2); break; case LOWPAN_IPHC_ADDR_03: fail = false; switch (addr_type) { case IEEE802154_ADDR_LONG: /* fe:80::XXXX:XXXX:XXXX:XXXX * \_________________/ * hwaddr */ ipaddr->s6_addr[0] = 0xFE; ipaddr->s6_addr[1] = 0x80; memcpy(&ipaddr->s6_addr[8], lladdr, addr_len); /* second bit-flip (Universe/Local) * is done according RFC2464 */ ipaddr->s6_addr[8] ^= 0x02; break; case IEEE802154_ADDR_SHORT: /* fe:80::ff:fe00:XXXX * \__/ * short_addr * * Universe/Local bit is zero. */ ipaddr->s6_addr[0] = 0xFE; ipaddr->s6_addr[1] = 0x80; ipaddr->s6_addr[11] = 0xFF; ipaddr->s6_addr[12] = 0xFE; ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr)); break; default: pr_debug("Invalid addr_type set\n"); return -EINVAL; } break; default: pr_debug("Invalid address mode value: 0x%x\n", address_mode); return -EINVAL; } if (fail) { pr_debug("Failed to fetch skb data\n"); return -EIO; } raw_dump_inline(NULL, "Reconstructed ipv6 addr is", ipaddr->s6_addr, 16); return 0; } /* Uncompress address function for source context * based address(non-multicast). */ static int uncompress_context_based_src_addr(struct sk_buff *skb, struct in6_addr *ipaddr, const u8 sam) { switch (sam) { case LOWPAN_IPHC_ADDR_00: /* unspec address :: * Do nothing, address is already :: */ break; case LOWPAN_IPHC_ADDR_01: /* TODO */ case LOWPAN_IPHC_ADDR_02: /* TODO */ case LOWPAN_IPHC_ADDR_03: /* TODO */ netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam); return -EINVAL; default: pr_debug("Invalid sam value: 0x%x\n", sam); return -EINVAL; } raw_dump_inline(NULL, "Reconstructed context based ipv6 src addr is", ipaddr->s6_addr, 16); return 0; } /* Uncompress function for multicast destination address, * when M bit is set. */ static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb, struct in6_addr *ipaddr, const u8 dam) { bool fail; switch (dam) { case LOWPAN_IPHC_DAM_00: /* 00: 128 bits. The full address * is carried in-line. */ fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16); break; case LOWPAN_IPHC_DAM_01: /* 01: 48 bits. The address takes * the form ffXX::00XX:XXXX:XXXX. */ ipaddr->s6_addr[0] = 0xFF; fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1); fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5); break; case LOWPAN_IPHC_DAM_10: /* 10: 32 bits. The address takes * the form ffXX::00XX:XXXX. */ ipaddr->s6_addr[0] = 0xFF; fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1); fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3); break; case LOWPAN_IPHC_DAM_11: /* 11: 8 bits. The address takes * the form ff02::00XX. */ ipaddr->s6_addr[0] = 0xFF; ipaddr->s6_addr[1] = 0x02; fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1); break; default: pr_debug("DAM value has a wrong value: 0x%x\n", dam); return -EINVAL; } if (fail) { pr_debug("Failed to fetch skb data\n"); return -EIO; } raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is", ipaddr->s6_addr, 16); return 0; } /* TTL uncompression values */ static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 }; int lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev, const u8 *saddr, const u8 saddr_type, const u8 saddr_len, const u8 *daddr, const u8 daddr_type, const u8 daddr_len, u8 iphc0, u8 iphc1) { struct ipv6hdr hdr = {}; u8 tmp, num_context = 0; int err; raw_dump_table(__func__, "raw skb data dump uncompressed", skb->data, skb->len); /* another if the CID flag is set */ if (iphc1 & LOWPAN_IPHC_CID) { pr_debug("CID flag is set, increase header with one\n"); if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context))) return -EINVAL; } hdr.version = 6; /* Traffic Class and Flow Label */ switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) { /* Traffic Class and FLow Label carried in-line * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) */ case 0: /* 00b */ if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) return -EINVAL; memcpy(&hdr.flow_lbl, &skb->data[0], 3); skb_pull(skb, 3); hdr.priority = ((tmp >> 2) & 0x0f); hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) | (hdr.flow_lbl[0] & 0x0f); break; /* Traffic class carried in-line * ECN + DSCP (1 byte), Flow Label is elided */ case 2: /* 10b */ if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) return -EINVAL; hdr.priority = ((tmp >> 2) & 0x0f); hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30); break; /* Flow Label carried in-line * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided */ case 1: /* 01b */ if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp))) return -EINVAL; hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30); memcpy(&hdr.flow_lbl[1], &skb->data[0], 2); skb_pull(skb, 2); break; /* Traffic Class and Flow Label are elided */ case 3: /* 11b */ break; default: break; } /* Next Header */ if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) { /* Next header is carried inline */ if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr))) return -EINVAL; pr_debug("NH flag is set, next header carried inline: %02x\n", hdr.nexthdr); } /* Hop Limit */ if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) { hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03]; } else { if (lowpan_fetch_skb(skb, &hdr.hop_limit, sizeof(hdr.hop_limit))) return -EINVAL; } /* Extract SAM to the tmp variable */ tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03; if (iphc1 & LOWPAN_IPHC_SAC) { /* Source address context based uncompression */ pr_debug("SAC bit is set. Handle context based source address.\n"); err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp); } else { /* Source address uncompression */ pr_debug("source address stateless compression\n"); err = uncompress_addr(skb, &hdr.saddr, tmp, saddr, saddr_type, saddr_len); } /* Check on error of previous branch */ if (err) return -EINVAL; /* Extract DAM to the tmp variable */ tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03; /* check for Multicast Compression */ if (iphc1 & LOWPAN_IPHC_M) { if (iphc1 & LOWPAN_IPHC_DAC) { pr_debug("dest: context-based mcast compression\n"); /* TODO: implement this */ } else { err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr, tmp); if (err) return -EINVAL; } } else { err = uncompress_addr(skb, &hdr.daddr, tmp, daddr, daddr_type, daddr_len); pr_debug("dest: stateless compression mode %d dest %pI6c\n", tmp, &hdr.daddr); if (err) return -EINVAL; } /* Next header data uncompression */ if (iphc0 & LOWPAN_IPHC_NH_C) { err = lowpan_nhc_do_uncompression(skb, dev, &hdr); if (err < 0) return err; } else { err = skb_cow(skb, sizeof(hdr)); if (unlikely(err)) return err; } hdr.payload_len = htons(skb->len); pr_debug("skb headroom size = %d, data length = %d\n", skb_headroom(skb), skb->len); pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t" "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n", hdr.version, ntohs(hdr.payload_len), hdr.nexthdr, hdr.hop_limit, &hdr.daddr); skb_push(skb, sizeof(hdr)); skb_reset_network_header(skb); skb_copy_to_linear_data(skb, &hdr, sizeof(hdr)); raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr)); return 0; } EXPORT_SYMBOL_GPL(lowpan_header_decompress); static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift, const struct in6_addr *ipaddr, const unsigned char *lladdr) { u8 val = 0; if (is_addr_mac_addr_based(ipaddr, lladdr)) { val = 3; /* 0-bits */ pr_debug("address compression 0 bits\n"); } else if (lowpan_is_iid_16_bit_compressable(ipaddr)) { /* compress IID to 16 bits xxxx::XXXX */ lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2); val = 2; /* 16-bits */ raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)", *hc_ptr - 2, 2); } else { /* do not compress IID => xxxx::IID */ lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8); val = 1; /* 64-bits */ raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)", *hc_ptr - 8, 8); } return rol8(val, shift); } int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev, unsigned short type, const void *_daddr, const void *_saddr, unsigned int len) { u8 tmp, iphc0, iphc1, *hc_ptr; struct ipv6hdr *hdr; u8 head[100] = {}; int ret, addr_type; if (type != ETH_P_IPV6) return -EINVAL; hdr = ipv6_hdr(skb); hc_ptr = head + 2; pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n" "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n", hdr->version, ntohs(hdr->payload_len), hdr->nexthdr, hdr->hop_limit, &hdr->daddr); raw_dump_table(__func__, "raw skb network header dump", skb_network_header(skb), sizeof(struct ipv6hdr)); /* As we copy some bit-length fields, in the IPHC encoding bytes, * we sometimes use |= * If the field is 0, and the current bit value in memory is 1, * this does not work. We therefore reset the IPHC encoding here */ iphc0 = LOWPAN_DISPATCH_IPHC; iphc1 = 0; /* TODO: context lookup */ raw_dump_inline(__func__, "saddr", (unsigned char *)_saddr, IEEE802154_ADDR_LEN); raw_dump_inline(__func__, "daddr", (unsigned char *)_daddr, IEEE802154_ADDR_LEN); raw_dump_table(__func__, "sending raw skb network uncompressed packet", skb->data, skb->len); /* Traffic class, flow label * If flow label is 0, compress it. If traffic class is 0, compress it * We have to process both in the same time as the offset of traffic * class depends on the presence of version and flow label */ /* hc format of TC is ECN | DSCP , original one is DSCP | ECN */ tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4); tmp = ((tmp & 0x03) << 6) | (tmp >> 2); if (((hdr->flow_lbl[0] & 0x0F) == 0) && (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) { /* flow label can be compressed */ iphc0 |= LOWPAN_IPHC_FL_C; if ((hdr->priority == 0) && ((hdr->flow_lbl[0] & 0xF0) == 0)) { /* compress (elide) all */ iphc0 |= LOWPAN_IPHC_TC_C; } else { /* compress only the flow label */ *hc_ptr = tmp; hc_ptr += 1; } } else { /* Flow label cannot be compressed */ if ((hdr->priority == 0) && ((hdr->flow_lbl[0] & 0xF0) == 0)) { /* compress only traffic class */ iphc0 |= LOWPAN_IPHC_TC_C; *hc_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F); memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2); hc_ptr += 3; } else { /* compress nothing */ memcpy(hc_ptr, hdr, 4); /* replace the top byte with new ECN | DSCP format */ *hc_ptr = tmp; hc_ptr += 4; } } /* NOTE: payload length is always compressed */ /* Check if we provide the nhc format for nexthdr and compression * functionality. If not nexthdr is handled inline and not compressed. */ ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr, &iphc0); if (ret < 0) return ret; /* Hop limit * if 1: compress, encoding is 01 * if 64: compress, encoding is 10 * if 255: compress, encoding is 11 * else do not compress */ switch (hdr->hop_limit) { case 1: iphc0 |= LOWPAN_IPHC_TTL_1; break; case 64: iphc0 |= LOWPAN_IPHC_TTL_64; break; case 255: iphc0 |= LOWPAN_IPHC_TTL_255; break; default: lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit, sizeof(hdr->hop_limit)); } addr_type = ipv6_addr_type(&hdr->saddr); /* source address compression */ if (addr_type == IPV6_ADDR_ANY) { pr_debug("source address is unspecified, setting SAC\n"); iphc1 |= LOWPAN_IPHC_SAC; } else { if (addr_type & IPV6_ADDR_LINKLOCAL) { iphc1 |= lowpan_compress_addr_64(&hc_ptr, LOWPAN_IPHC_SAM_BIT, &hdr->saddr, _saddr); pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n", &hdr->saddr, iphc1); } else { pr_debug("send the full source address\n"); lowpan_push_hc_data(&hc_ptr, hdr->saddr.s6_addr, 16); } } addr_type = ipv6_addr_type(&hdr->daddr); /* destination address compression */ if (addr_type & IPV6_ADDR_MULTICAST) { pr_debug("destination address is multicast: "); iphc1 |= LOWPAN_IPHC_M; if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) { pr_debug("compressed to 1 octet\n"); iphc1 |= LOWPAN_IPHC_DAM_11; /* use last byte */ lowpan_push_hc_data(&hc_ptr, &hdr->daddr.s6_addr[15], 1); } else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) { pr_debug("compressed to 4 octets\n"); iphc1 |= LOWPAN_IPHC_DAM_10; /* second byte + the last three */ lowpan_push_hc_data(&hc_ptr, &hdr->daddr.s6_addr[1], 1); lowpan_push_hc_data(&hc_ptr, &hdr->daddr.s6_addr[13], 3); } else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) { pr_debug("compressed to 6 octets\n"); iphc1 |= LOWPAN_IPHC_DAM_01; /* second byte + the last five */ lowpan_push_hc_data(&hc_ptr, &hdr->daddr.s6_addr[1], 1); lowpan_push_hc_data(&hc_ptr, &hdr->daddr.s6_addr[11], 5); } else { pr_debug("using full address\n"); iphc1 |= LOWPAN_IPHC_DAM_00; lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16); } } else { if (addr_type & IPV6_ADDR_LINKLOCAL) { /* TODO: context lookup */ iphc1 |= lowpan_compress_addr_64(&hc_ptr, LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr); pr_debug("dest address unicast link-local %pI6c " "iphc1 0x%02x\n", &hdr->daddr, iphc1); } else { pr_debug("dest address unicast %pI6c\n", &hdr->daddr); lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16); } } /* next header compression */ if (iphc0 & LOWPAN_IPHC_NH_C) { ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr); if (ret < 0) return ret; } head[0] = iphc0; head[1] = iphc1; skb_pull(skb, sizeof(struct ipv6hdr)); skb_reset_transport_header(skb); memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head); skb_reset_network_header(skb); pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len); raw_dump_table(__func__, "raw skb data dump compressed", skb->data, skb->len); return 0; } EXPORT_SYMBOL_GPL(lowpan_header_compress); static int __init lowpan_module_init(void) { request_module_nowait("nhc_dest"); request_module_nowait("nhc_fragment"); request_module_nowait("nhc_hop"); request_module_nowait("nhc_ipv6"); request_module_nowait("nhc_mobility"); request_module_nowait("nhc_routing"); request_module_nowait("nhc_udp"); return 0; } module_init(lowpan_module_init); MODULE_LICENSE("GPL");