diff options
Diffstat (limited to 'net/6lowpan/iphc.c')
| -rw-r--r-- | net/6lowpan/iphc.c | 801 |
1 files changed, 801 insertions, 0 deletions
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c new file mode 100644 index 000000000000..211b5686d719 --- /dev/null +++ b/net/6lowpan/iphc.c @@ -0,0 +1,801 @@ +/* + * Copyright 2011, Siemens AG + * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com> + */ + +/* + * Based on patches from Jon Smirl <jonsmirl@gmail.com> + * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com> + * + * 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. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/* 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 <linux/bitops.h> +#include <linux/if_arp.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <net/6lowpan.h> +#include <net/ipv6.h> +#include <net/af_ieee802154.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; +} + +static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr, + struct net_device *dev, skb_delivery_cb deliver_skb) +{ + struct sk_buff *new; + int stat; + + new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb), + GFP_ATOMIC); + kfree_skb(skb); + + if (!new) + return -ENOMEM; + + skb_push(new, sizeof(struct ipv6hdr)); + skb_reset_network_header(new); + skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr)); + + new->protocol = htons(ETH_P_IPV6); + new->pkt_type = PACKET_HOST; + new->dev = dev; + + raw_dump_table(__func__, "raw skb data dump before receiving", + new->data, new->len); + + stat = deliver_skb(new, dev); + + kfree_skb(new); + + return stat; +} + +/* 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; +} + +static int +uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh) +{ + bool fail; + u8 tmp = 0, val = 0; + + if (!uh) + goto err; + + fail = lowpan_fetch_skb(skb, &tmp, 1); + + if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) { + pr_debug("UDP header uncompression\n"); + switch (tmp & LOWPAN_NHC_UDP_CS_P_11) { + case LOWPAN_NHC_UDP_CS_P_00: + fail |= lowpan_fetch_skb(skb, &uh->source, 2); + fail |= lowpan_fetch_skb(skb, &uh->dest, 2); + break; + case LOWPAN_NHC_UDP_CS_P_01: + fail |= lowpan_fetch_skb(skb, &uh->source, 2); + fail |= lowpan_fetch_skb(skb, &val, 1); + uh->dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT); + break; + case LOWPAN_NHC_UDP_CS_P_10: + fail |= lowpan_fetch_skb(skb, &val, 1); + uh->source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT); + fail |= lowpan_fetch_skb(skb, &uh->dest, 2); + break; + case LOWPAN_NHC_UDP_CS_P_11: + fail |= lowpan_fetch_skb(skb, &val, 1); + uh->source = htons(LOWPAN_NHC_UDP_4BIT_PORT + + (val >> 4)); + uh->dest = htons(LOWPAN_NHC_UDP_4BIT_PORT + + (val & 0x0f)); + break; + default: + pr_debug("ERROR: unknown UDP format\n"); + goto err; + break; + } + + pr_debug("uncompressed UDP ports: src = %d, dst = %d\n", + ntohs(uh->source), ntohs(uh->dest)); + + /* checksum */ + if (tmp & LOWPAN_NHC_UDP_CS_C) { + pr_debug_ratelimited("checksum elided currently not supported\n"); + goto err; + } else { + fail |= lowpan_fetch_skb(skb, &uh->check, 2); + } + + /* + * UDP lenght needs to be infered from the lower layers + * here, we obtain the hint from the remaining size of the + * frame + */ + uh->len = htons(skb->len + sizeof(struct udphdr)); + pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len)); + } else { + pr_debug("ERROR: unsupported NH format\n"); + goto err; + } + + if (fail) + goto err; + + return 0; +err: + return -EINVAL; +} + +/* TTL uncompression values */ +static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 }; + +int lowpan_process_data(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, skb_delivery_cb deliver_skb) +{ + 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_u8(skb, &num_context)) + goto drop; + } + + 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_u8(skb, &tmp)) + goto drop; + + 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_u8(skb, &tmp)) + goto drop; + + 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_u8(skb, &tmp)) + goto drop; + + 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_u8(skb, &(hdr.nexthdr))) + goto drop; + + 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_u8(skb, &(hdr.hop_limit))) + goto drop; + } + + /* 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) + goto drop; + + /* 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) + goto drop; + } + } 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) + goto drop; + } + + /* UDP data uncompression */ + if (iphc0 & LOWPAN_IPHC_NH_C) { + struct udphdr uh; + struct sk_buff *new; + if (uncompress_udp_header(skb, &uh)) + goto drop; + + /* + * replace the compressed UDP head by the uncompressed UDP + * header + */ + new = skb_copy_expand(skb, sizeof(struct udphdr), + skb_tailroom(skb), GFP_ATOMIC); + kfree_skb(skb); + + if (!new) + return -ENOMEM; + + skb = new; + + skb_push(skb, sizeof(struct udphdr)); + skb_reset_transport_header(skb); + skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr)); + + raw_dump_table(__func__, "raw UDP header dump", + (u8 *)&uh, sizeof(uh)); + + hdr.nexthdr = UIP_PROTO_UDP; + } + + 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); + + raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, + sizeof(hdr)); + + return skb_deliver(skb, &hdr, dev, deliver_skb); + +drop: + kfree_skb(skb); + return -EINVAL; +} +EXPORT_SYMBOL_GPL(lowpan_process_data); + +static u8 lowpan_compress_addr_64(u8 **hc06_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 */ + memcpy(*hc06_ptr, &ipaddr->s6_addr16[7], 2); + *hc06_ptr += 2; + val = 2; /* 16-bits */ + raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)", + *hc06_ptr - 2, 2); + } else { + /* do not compress IID => xxxx::IID */ + memcpy(*hc06_ptr, &ipaddr->s6_addr16[4], 8); + *hc06_ptr += 8; + val = 1; /* 64-bits */ + raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)", + *hc06_ptr - 8, 8); + } + + return rol8(val, shift); +} + +static void compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb) +{ + struct udphdr *uh = udp_hdr(skb); + u8 tmp; + + if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) == + LOWPAN_NHC_UDP_4BIT_PORT) && + ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) == + LOWPAN_NHC_UDP_4BIT_PORT)) { + pr_debug("UDP header: both ports compression to 4 bits\n"); + /* compression value */ + tmp = LOWPAN_NHC_UDP_CS_P_11; + lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp)); + /* source and destination port */ + tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT + + ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4); + lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp)); + } else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) == + LOWPAN_NHC_UDP_8BIT_PORT) { + pr_debug("UDP header: remove 8 bits of dest\n"); + /* compression value */ + tmp = LOWPAN_NHC_UDP_CS_P_01; + lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp)); + /* source port */ + lowpan_push_hc_data(hc06_ptr, &uh->source, sizeof(uh->source)); + /* destination port */ + tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT; + lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp)); + } else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) == + LOWPAN_NHC_UDP_8BIT_PORT) { + pr_debug("UDP header: remove 8 bits of source\n"); + /* compression value */ + tmp = LOWPAN_NHC_UDP_CS_P_10; + lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp)); + /* source port */ + tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT; + lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp)); + /* destination port */ + lowpan_push_hc_data(hc06_ptr, &uh->dest, sizeof(uh->dest)); + } else { + pr_debug("UDP header: can't compress\n"); + /* compression value */ + tmp = LOWPAN_NHC_UDP_CS_P_00; + lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp)); + /* source port */ + lowpan_push_hc_data(hc06_ptr, &uh->source, sizeof(uh->source)); + /* destination port */ + lowpan_push_hc_data(hc06_ptr, &uh->dest, sizeof(uh->dest)); + } + + /* checksum is always inline */ + lowpan_push_hc_data(hc06_ptr, &uh->check, sizeof(uh->check)); + + /* skip the UDP header */ + skb_pull(skb, sizeof(struct udphdr)); +} + +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, *hc06_ptr; + struct ipv6hdr *hdr; + u8 head[100] = {}; + + if (type != ETH_P_IPV6) + return -EINVAL; + + hdr = ipv6_hdr(skb); + hc06_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 + */ + + /* hc06 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 */ + *hc06_ptr = tmp; + hc06_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; + *hc06_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F); + memcpy(hc06_ptr + 1, &hdr->flow_lbl[1], 2); + hc06_ptr += 3; + } else { + /* compress nothing */ + memcpy(hc06_ptr, hdr, 4); + /* replace the top byte with new ECN | DSCP format */ + *hc06_ptr = tmp; + hc06_ptr += 4; + } + } + + /* NOTE: payload length is always compressed */ + + /* Next Header is compress if UDP */ + if (hdr->nexthdr == UIP_PROTO_UDP) + iphc0 |= LOWPAN_IPHC_NH_C; + + if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) { + *hc06_ptr = hdr->nexthdr; + hc06_ptr += 1; + } + + /* + * 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: + *hc06_ptr = hdr->hop_limit; + hc06_ptr += 1; + break; + } + + /* source address compression */ + if (is_addr_unspecified(&hdr->saddr)) { + pr_debug("source address is unspecified, setting SAC\n"); + iphc1 |= LOWPAN_IPHC_SAC; + /* TODO: context lookup */ + } else if (is_addr_link_local(&hdr->saddr)) { + iphc1 |= lowpan_compress_addr_64(&hc06_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"); + memcpy(hc06_ptr, &hdr->saddr.s6_addr16[0], 16); + hc06_ptr += 16; + } + + /* destination address compression */ + if (is_addr_mcast(&hdr->daddr)) { + 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 */ + *hc06_ptr = hdr->daddr.s6_addr[15]; + hc06_ptr += 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 */ + *hc06_ptr = hdr->daddr.s6_addr[1]; + memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[13], 3); + hc06_ptr += 4; + } 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 */ + *hc06_ptr = hdr->daddr.s6_addr[1]; + memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[11], 5); + hc06_ptr += 6; + } else { + pr_debug("using full address\n"); + iphc1 |= LOWPAN_IPHC_DAM_00; + memcpy(hc06_ptr, &hdr->daddr.s6_addr[0], 16); + hc06_ptr += 16; + } + } else { + /* TODO: context lookup */ + if (is_addr_link_local(&hdr->daddr)) { + iphc1 |= lowpan_compress_addr_64(&hc06_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); + memcpy(hc06_ptr, &hdr->daddr.s6_addr16[0], 16); + hc06_ptr += 16; + } + } + + /* UDP header compression */ + if (hdr->nexthdr == UIP_PROTO_UDP) + compress_udp_header(&hc06_ptr, skb); + + head[0] = iphc0; + head[1] = iphc1; + + skb_pull(skb, sizeof(struct ipv6hdr)); + skb_reset_transport_header(skb); + memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head); + skb_reset_network_header(skb); + + pr_debug("header len %d skb %u\n", (int)(hc06_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); + +MODULE_LICENSE("GPL"); |