[deliverable/linux.git] / net / 6lowpan / iphc.c

/*
 * 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.
 *
 */

/* 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/netdevice.h>
#include <net/6lowpan.h>
#include <net/ipv6.h>
#include <net/af_ieee802154.h>

#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] = (tmp & 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);
Commit	Line	Data
8df8c56a JR	1	/*
	2	* Copyright 2011, Siemens AG
	3	* written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
	4	*/
	5
4710d806	6	/* Based on patches from Jon Smirl <jonsmirl@gmail.com>
8df8c56a JR	7	* Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2
	11	* as published by the Free Software Foundation.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
8df8c56a JR	18	*/
	19
	20	/* Jon's code is based on 6lowpan implementation for Contiki which is:
	21	* Copyright (c) 2008, Swedish Institute of Computer Science.
	22	* All rights reserved.
	23	*
	24	* Redistribution and use in source and binary forms, with or without
	25	* modification, are permitted provided that the following conditions
	26	* are met:
	27	* 1. Redistributions of source code must retain the above copyright
	28	* notice, this list of conditions and the following disclaimer.
	29	* 2. Redistributions in binary form must reproduce the above copyright
	30	* notice, this list of conditions and the following disclaimer in the
	31	* documentation and/or other materials provided with the distribution.
	32	* 3. Neither the name of the Institute nor the names of its contributors
	33	* may be used to endorse or promote products derived from this software
	34	* without specific prior written permission.
	35	*
	36	* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
	37	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	38	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	39	* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
	40	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	41	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	42	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	43	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	44	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	45	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	46	* SUCH DAMAGE.
	47	*/
	48
	49	#include <linux/bitops.h>
	50	#include <linux/if_arp.h>
	51	#include <linux/netdevice.h>
cefc8c8a	52	#include <net/6lowpan.h>
8df8c56a JR	53	#include <net/ipv6.h>
	54	#include <net/af_ieee802154.h>
	55
cc6ed268 AA	56	#include "nhc.h"
cc6ed268 AA	57
4710d806	58	/* Uncompress address function for source and
8df8c56a JR	59	* destination address(non-multicast).
	60	*
	61	* address_mode is sam value or dam value.
	62	*/
	63	static int uncompress_addr(struct sk_buff *skb,
4710d806 VB	64	struct in6_addr *ipaddr, const u8 address_mode,
	65	const u8 *lladdr, const u8 addr_type,
	66	const u8 addr_len)
8df8c56a JR	67	{
	68	bool fail;
	69
	70	switch (address_mode) {
	71	case LOWPAN_IPHC_ADDR_00:
	72	/* for global link addresses */
	73	fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
	74	break;
	75	case LOWPAN_IPHC_ADDR_01:
	76	/* fe:80::XXXX:XXXX:XXXX:XXXX */
	77	ipaddr->s6_addr[0] = 0xFE;
	78	ipaddr->s6_addr[1] = 0x80;
	79	fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
	80	break;
	81	case LOWPAN_IPHC_ADDR_02:
	82	/* fe:80::ff:fe00:XXXX */
	83	ipaddr->s6_addr[0] = 0xFE;
	84	ipaddr->s6_addr[1] = 0x80;
	85	ipaddr->s6_addr[11] = 0xFF;
	86	ipaddr->s6_addr[12] = 0xFE;
	87	fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
	88	break;
	89	case LOWPAN_IPHC_ADDR_03:
	90	fail = false;
	91	switch (addr_type) {
	92	case IEEE802154_ADDR_LONG:
	93	/* fe:80::XXXX:XXXX:XXXX:XXXX
	94	* \_________________/
	95	* hwaddr
	96	*/
	97	ipaddr->s6_addr[0] = 0xFE;
	98	ipaddr->s6_addr[1] = 0x80;
	99	memcpy(&ipaddr->s6_addr[8], lladdr, addr_len);
	100	/* second bit-flip (Universe/Local)
	101	* is done according RFC2464
	102	*/
	103	ipaddr->s6_addr[8] ^= 0x02;
	104	break;
	105	case IEEE802154_ADDR_SHORT:
	106	/* fe:80::ff:fe00:XXXX
	107	* \__/
	108	* short_addr
	109	*
	110	* Universe/Local bit is zero.
	111	*/
	112	ipaddr->s6_addr[0] = 0xFE;
	113	ipaddr->s6_addr[1] = 0x80;
	114	ipaddr->s6_addr[11] = 0xFF;
	115	ipaddr->s6_addr[12] = 0xFE;
	116	ipaddr->s6_addr16[7] = htons(((u16 )lladdr));
	117	break;
	118	default:
	119	pr_debug("Invalid addr_type set\n");
	120	return -EINVAL;
	121	}
	122	break;
	123	default:
	124	pr_debug("Invalid address mode value: 0x%x\n", address_mode);
	125	return -EINVAL;
	126	}
	127
	128	if (fail) {
	129	pr_debug("Failed to fetch skb data\n");
	130	return -EIO;
131	}
132
133	raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
134	ipaddr->s6_addr, 16);
135
136	return 0;
137	}
138
4710d806	139	/* Uncompress address function for source context
8df8c56a JR	140	* based address(non-multicast).
	141	*/
	142	static int uncompress_context_based_src_addr(struct sk_buff *skb,
4710d806 VB	143	struct in6_addr *ipaddr,
4710d806 VB	144	const u8 sam)
8df8c56a JR	145	{
	146	switch (sam) {
	147	case LOWPAN_IPHC_ADDR_00:
	148	/* unspec address ::
	149	* Do nothing, address is already ::
	150	*/
	151	break;
	152	case LOWPAN_IPHC_ADDR_01:
	153	/* TODO */
	154	case LOWPAN_IPHC_ADDR_02:
	155	/* TODO */
	156	case LOWPAN_IPHC_ADDR_03:
	157	/* TODO */
	158	netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
	159	return -EINVAL;
	160	default:
	161	pr_debug("Invalid sam value: 0x%x\n", sam);
	162	return -EINVAL;
	163	}
	164
	165	raw_dump_inline(NULL,
	166	"Reconstructed context based ipv6 src addr is",
	167	ipaddr->s6_addr, 16);
	168
	169	return 0;
	170	}
	171
8df8c56a JR	172	/* Uncompress function for multicast destination address,
	173	* when M bit is set.
	174	*/
7fc4cfda MH	175	static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
	176	struct in6_addr *ipaddr,
	177	const u8 dam)
8df8c56a JR	178	{
	179	bool fail;
	180
	181	switch (dam) {
	182	case LOWPAN_IPHC_DAM_00:
	183	/* 00: 128 bits. The full address
	184	* is carried in-line.
	185	*/
	186	fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
	187	break;
	188	case LOWPAN_IPHC_DAM_01:
	189	/* 01: 48 bits. The address takes
	190	* the form ffXX::00XX:XXXX:XXXX.
	191	*/
	192	ipaddr->s6_addr[0] = 0xFF;
	193	fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
	194	fail \|= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
	195	break;
	196	case LOWPAN_IPHC_DAM_10:
	197	/* 10: 32 bits. The address takes
	198	* the form ffXX::00XX:XXXX.
	199	*/
	200	ipaddr->s6_addr[0] = 0xFF;
	201	fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
	202	fail \|= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
	203	break;
	204	case LOWPAN_IPHC_DAM_11:
	205	/* 11: 8 bits. The address takes
	206	* the form ff02::00XX.
	207	*/
	208	ipaddr->s6_addr[0] = 0xFF;
	209	ipaddr->s6_addr[1] = 0x02;
	210	fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
	211	break;
	212	default:
	213	pr_debug("DAM value has a wrong value: 0x%x\n", dam);
	214	return -EINVAL;
	215	}
	216
	217	if (fail) {
	218	pr_debug("Failed to fetch skb data\n");
	219	return -EIO;
	220	}
	221
	222	raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
7fc4cfda	223	ipaddr->s6_addr, 16);
8df8c56a JR	224
	225	return 0;
	226	}
	227
8df8c56a JR	228	/* TTL uncompression values */
	229	static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
	230
01141234 MT	231	int
	232	lowpan_header_decompress(struct sk_buff skb, struct net_device dev,
	233	const u8 *saddr, const u8 saddr_type,
	234	const u8 saddr_len, const u8 *daddr,
	235	const u8 daddr_type, const u8 daddr_len,
	236	u8 iphc0, u8 iphc1)
8df8c56a JR	237	{
	238	struct ipv6hdr hdr = {};
	239	u8 tmp, num_context = 0;
	240	int err;
	241
	242	raw_dump_table(__func__, "raw skb data dump uncompressed",
4710d806	243	skb->data, skb->len);
8df8c56a JR	244
	245	/* another if the CID flag is set */
	246	if (iphc1 & LOWPAN_IPHC_CID) {
	247	pr_debug("CID flag is set, increase header with one\n");
4ebc960f	248	if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context)))
56b2c3ee	249	return -EINVAL;
8df8c56a JR	250	}
	251
	252	hdr.version = 6;
	253
	254	/* Traffic Class and Flow Label */
	255	switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
4710d806	256	/* Traffic Class and FLow Label carried in-line
8df8c56a JR	257	* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
	258	*/
	259	case 0: /* 00b */
4ebc960f	260	if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
56b2c3ee	261	return -EINVAL;
8df8c56a JR	262
	263	memcpy(&hdr.flow_lbl, &skb->data[0], 3);
	264	skb_pull(skb, 3);
	265	hdr.priority = ((tmp >> 2) & 0x0f);
	266	hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) \| (tmp << 6) \|
	267	(hdr.flow_lbl[0] & 0x0f);
	268	break;
4710d806	269	/* Traffic class carried in-line
8df8c56a JR	270	* ECN + DSCP (1 byte), Flow Label is elided
	271	*/
	272	case 2: /* 10b */
4ebc960f	273	if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
56b2c3ee	274	return -EINVAL;
8df8c56a JR	275
	276	hdr.priority = ((tmp >> 2) & 0x0f);
	277	hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) \| ((tmp >> 2) & 0x30);
	278	break;
4710d806	279	/* Flow Label carried in-line
8df8c56a JR	280	* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
	281	*/
	282	case 1: /* 01b */
4ebc960f	283	if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
56b2c3ee	284	return -EINVAL;
8df8c56a	285
77e867b5	286	hdr.flow_lbl[0] = (tmp & 0x0F) \| ((tmp >> 2) & 0x30);
8df8c56a JR	287	memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
	288	skb_pull(skb, 2);
	289	break;
	290	/* Traffic Class and Flow Label are elided */
	291	case 3: /* 11b */
	292	break;
	293	default:
	294	break;
	295	}
	296
	297	/* Next Header */
	298	if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
	299	/* Next header is carried inline */
4ebc960f	300	if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
56b2c3ee	301	return -EINVAL;
8df8c56a JR	302
	303	pr_debug("NH flag is set, next header carried inline: %02x\n",
	304	hdr.nexthdr);
	305	}
	306
	307	/* Hop Limit */
4710d806	308	if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) {
8df8c56a	309	hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
4710d806	310	} else {
4ebc960f AA	311	if (lowpan_fetch_skb(skb, &hdr.hop_limit,
4ebc960f AA	312	sizeof(hdr.hop_limit)))
56b2c3ee	313	return -EINVAL;
8df8c56a JR	314	}
	315
	316	/* Extract SAM to the tmp variable */
	317	tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
	318
	319	if (iphc1 & LOWPAN_IPHC_SAC) {
	320	/* Source address context based uncompression */
	321	pr_debug("SAC bit is set. Handle context based source address.\n");
7fc4cfda	322	err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp);
8df8c56a JR	323	} else {
	324	/* Source address uncompression */
	325	pr_debug("source address stateless compression\n");
	326	err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
4710d806	327	saddr_type, saddr_len);
8df8c56a JR	328	}
	329
	330	/* Check on error of previous branch */
	331	if (err)
56b2c3ee	332	return -EINVAL;
8df8c56a JR	333
	334	/* Extract DAM to the tmp variable */
	335	tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
	336
	337	/* check for Multicast Compression */
	338	if (iphc1 & LOWPAN_IPHC_M) {
	339	if (iphc1 & LOWPAN_IPHC_DAC) {
	340	pr_debug("dest: context-based mcast compression\n");
	341	/* TODO: implement this */
	342	} else {
7fc4cfda MH	343	err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
	344	tmp);
	345
8df8c56a	346	if (err)
56b2c3ee	347	return -EINVAL;
8df8c56a JR	348	}
	349	} else {
	350	err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
4710d806	351	daddr_type, daddr_len);
8df8c56a	352	pr_debug("dest: stateless compression mode %d dest %pI6c\n",
4710d806	353	tmp, &hdr.daddr);
8df8c56a	354	if (err)
56b2c3ee	355	return -EINVAL;
8df8c56a JR	356	}
8df8c56a JR	357
cc6ed268	358	/* Next header data uncompression */
8df8c56a	359	if (iphc0 & LOWPAN_IPHC_NH_C) {
cc6ed268 AA	360	err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
cc6ed268 AA	361	if (err < 0)
11e3ff70	362	return err;
11e3ff70 MT	363	} else {
11e3ff70 MT	364	err = skb_cow(skb, sizeof(hdr));
56b2c3ee	365	if (unlikely(err))
11e3ff70	366	return err;
8df8c56a JR	367	}
	368
	369	hdr.payload_len = htons(skb->len);
	370
	371	pr_debug("skb headroom size = %d, data length = %d\n",
	372	skb_headroom(skb), skb->len);
	373
	374	pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
	375	"nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
	376	hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
	377	hdr.hop_limit, &hdr.daddr);
	378
f8b36176 MT	379	skb_push(skb, sizeof(hdr));
	380	skb_reset_network_header(skb);
	381	skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
8df8c56a	382
f8b36176	383	raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
8df8c56a	384
f8b36176	385	return 0;
8df8c56a	386	}
01141234	387	EXPORT_SYMBOL_GPL(lowpan_header_decompress);
8df8c56a	388
84ca5e03	389	static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift,
4710d806 VB	390	const struct in6_addr *ipaddr,
4710d806 VB	391	const unsigned char *lladdr)
8df8c56a JR	392	{
	393	u8 val = 0;
	394
	395	if (is_addr_mac_addr_based(ipaddr, lladdr)) {
	396	val = 3; /* 0-bits */
	397	pr_debug("address compression 0 bits\n");
	398	} else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
	399	/* compress IID to 16 bits xxxx::XXXX */
85c71240	400	lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
8df8c56a JR	401	val = 2; /* 16-bits */
8df8c56a JR	402	raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
84ca5e03	403	*hc_ptr - 2, 2);
8df8c56a JR	404	} else {
8df8c56a JR	405	/* do not compress IID => xxxx::IID */
85c71240	406	lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
8df8c56a JR	407	val = 1; /* 64-bits */
8df8c56a JR	408	raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
84ca5e03	409	*hc_ptr - 8, 8);
8df8c56a JR	410	}
	411
	412	return rol8(val, shift);
	413	}
	414
8df8c56a	415	int lowpan_header_compress(struct sk_buff skb, struct net_device dev,
4710d806 VB	416	unsigned short type, const void *_daddr,
4710d806 VB	417	const void *_saddr, unsigned int len)
8df8c56a	418	{
84ca5e03	419	u8 tmp, iphc0, iphc1, *hc_ptr;
8df8c56a JR	420	struct ipv6hdr *hdr;
8df8c56a JR	421	u8 head[100] = {};
cc6ed268	422	int ret, addr_type;
8df8c56a JR	423
	424	if (type != ETH_P_IPV6)
	425	return -EINVAL;
	426
	427	hdr = ipv6_hdr(skb);
84ca5e03	428	hc_ptr = head + 2;
8df8c56a JR	429
	430	pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
	431	"\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
4710d806 VB	432	hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
4710d806 VB	433	hdr->hop_limit, &hdr->daddr);
8df8c56a JR	434
8df8c56a JR	435	raw_dump_table(__func__, "raw skb network header dump",
4710d806	436	skb_network_header(skb), sizeof(struct ipv6hdr));
8df8c56a	437
4710d806	438	/* As we copy some bit-length fields, in the IPHC encoding bytes,
8df8c56a JR	439	* we sometimes use \|=
	440	* If the field is 0, and the current bit value in memory is 1,
	441	* this does not work. We therefore reset the IPHC encoding here
	442	*/
	443	iphc0 = LOWPAN_DISPATCH_IPHC;
	444	iphc1 = 0;
	445
	446	/* TODO: context lookup */
	447
	448	raw_dump_inline(__func__, "saddr",
	449	(unsigned char *)_saddr, IEEE802154_ADDR_LEN);
	450	raw_dump_inline(__func__, "daddr",
	451	(unsigned char *)_daddr, IEEE802154_ADDR_LEN);
	452
7fc4cfda	453	raw_dump_table(__func__, "sending raw skb network uncompressed packet",
4710d806	454	skb->data, skb->len);
8df8c56a	455
4710d806	456	/* Traffic class, flow label
8df8c56a JR	457	* If flow label is 0, compress it. If traffic class is 0, compress it
	458	* We have to process both in the same time as the offset of traffic
	459	* class depends on the presence of version and flow label
	460	*/
	461
84ca5e03	462	/* hc format of TC is ECN \| DSCP , original one is DSCP \| ECN */
8df8c56a JR	463	tmp = (hdr->priority << 4) \| (hdr->flow_lbl[0] >> 4);
	464	tmp = ((tmp & 0x03) << 6) \| (tmp >> 2);
	465
	466	if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
4710d806	467	(hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
8df8c56a JR	468	/* flow label can be compressed */
	469	iphc0 \|= LOWPAN_IPHC_FL_C;
	470	if ((hdr->priority == 0) &&
4710d806	471	((hdr->flow_lbl[0] & 0xF0) == 0)) {
8df8c56a JR	472	/* compress (elide) all */
	473	iphc0 \|= LOWPAN_IPHC_TC_C;
	474	} else {
	475	/* compress only the flow label */
84ca5e03 AA	476	*hc_ptr = tmp;
84ca5e03 AA	477	hc_ptr += 1;
8df8c56a JR	478	}
	479	} else {
	480	/* Flow label cannot be compressed */
	481	if ((hdr->priority == 0) &&
4710d806	482	((hdr->flow_lbl[0] & 0xF0) == 0)) {
8df8c56a JR	483	/* compress only traffic class */
8df8c56a JR	484	iphc0 \|= LOWPAN_IPHC_TC_C;
84ca5e03 AA	485	*hc_ptr = (tmp & 0xc0) \| (hdr->flow_lbl[0] & 0x0F);
	486	memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2);
	487	hc_ptr += 3;
8df8c56a JR	488	} else {
8df8c56a JR	489	/* compress nothing */
84ca5e03	490	memcpy(hc_ptr, hdr, 4);
8df8c56a	491	/* replace the top byte with new ECN \| DSCP format */
84ca5e03 AA	492	*hc_ptr = tmp;
84ca5e03 AA	493	hc_ptr += 4;
8df8c56a JR	494	}
	495	}
	496
	497	/* NOTE: payload length is always compressed */
	498
cc6ed268 AA	499	/* Check if we provide the nhc format for nexthdr and compression
	500	* functionality. If not nexthdr is handled inline and not compressed.
	501	*/
	502	ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr, &iphc0);
	503	if (ret < 0)
	504	return ret;
8df8c56a	505
4710d806	506	/* Hop limit
8df8c56a JR	507	* if 1: compress, encoding is 01
	508	* if 64: compress, encoding is 10
	509	* if 255: compress, encoding is 11
	510	* else do not compress
	511	*/
	512	switch (hdr->hop_limit) {
	513	case 1:
	514	iphc0 \|= LOWPAN_IPHC_TTL_1;
	515	break;
	516	case 64:
	517	iphc0 \|= LOWPAN_IPHC_TTL_64;
	518	break;
	519	case 255:
	520	iphc0 \|= LOWPAN_IPHC_TTL_255;
	521	break;
	522	default:
85c71240 AA	523	lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
85c71240 AA	524	sizeof(hdr->hop_limit));
8df8c56a JR	525	}
8df8c56a JR	526
556a5bfc	527	addr_type = ipv6_addr_type(&hdr->saddr);
8df8c56a	528	/* source address compression */
556a5bfc	529	if (addr_type == IPV6_ADDR_ANY) {
8df8c56a JR	530	pr_debug("source address is unspecified, setting SAC\n");
8df8c56a JR	531	iphc1 \|= LOWPAN_IPHC_SAC;
8df8c56a	532	} else {
556a5bfc AA	533	if (addr_type & IPV6_ADDR_LINKLOCAL) {
	534	iphc1 \|= lowpan_compress_addr_64(&hc_ptr,
	535	LOWPAN_IPHC_SAM_BIT,
	536	&hdr->saddr, _saddr);
	537	pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
	538	&hdr->saddr, iphc1);
	539	} else {
	540	pr_debug("send the full source address\n");
	541	lowpan_push_hc_data(&hc_ptr, hdr->saddr.s6_addr, 16);
	542	}
8df8c56a JR	543	}
8df8c56a JR	544
556a5bfc	545	addr_type = ipv6_addr_type(&hdr->daddr);
8df8c56a	546	/* destination address compression */
556a5bfc	547	if (addr_type & IPV6_ADDR_MULTICAST) {
8df8c56a JR	548	pr_debug("destination address is multicast: ");
	549	iphc1 \|= LOWPAN_IPHC_M;
	550	if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
	551	pr_debug("compressed to 1 octet\n");
	552	iphc1 \|= LOWPAN_IPHC_DAM_11;
	553	/* use last byte */
85c71240 AA	554	lowpan_push_hc_data(&hc_ptr,
85c71240 AA	555	&hdr->daddr.s6_addr[15], 1);
8df8c56a JR	556	} else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
	557	pr_debug("compressed to 4 octets\n");
	558	iphc1 \|= LOWPAN_IPHC_DAM_10;
	559	/* second byte + the last three */
85c71240 AA	560	lowpan_push_hc_data(&hc_ptr,
	561	&hdr->daddr.s6_addr[1], 1);
	562	lowpan_push_hc_data(&hc_ptr,
	563	&hdr->daddr.s6_addr[13], 3);
8df8c56a JR	564	} else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
	565	pr_debug("compressed to 6 octets\n");
	566	iphc1 \|= LOWPAN_IPHC_DAM_01;
	567	/* second byte + the last five */
85c71240 AA	568	lowpan_push_hc_data(&hc_ptr,
	569	&hdr->daddr.s6_addr[1], 1);
	570	lowpan_push_hc_data(&hc_ptr,
	571	&hdr->daddr.s6_addr[11], 5);
8df8c56a JR	572	} else {
	573	pr_debug("using full address\n");
	574	iphc1 \|= LOWPAN_IPHC_DAM_00;
85c71240	575	lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
8df8c56a JR	576	}
8df8c56a JR	577	} else {
556a5bfc AA	578	if (addr_type & IPV6_ADDR_LINKLOCAL) {
556a5bfc AA	579	/* TODO: context lookup */
84ca5e03	580	iphc1 \|= lowpan_compress_addr_64(&hc_ptr,
8df8c56a JR	581	LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr);
8df8c56a JR	582	pr_debug("dest address unicast link-local %pI6c "
7fc4cfda	583	"iphc1 0x%02x\n", &hdr->daddr, iphc1);
8df8c56a JR	584	} else {
8df8c56a JR	585	pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
85c71240	586	lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
8df8c56a JR	587	}
	588	}
	589
cc6ed268 AA	590	/* next header compression */
	591	if (iphc0 & LOWPAN_IPHC_NH_C) {
	592	ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
	593	if (ret < 0)
	594	return ret;
	595	}
8df8c56a JR	596
	597	head[0] = iphc0;
	598	head[1] = iphc1;
	599
	600	skb_pull(skb, sizeof(struct ipv6hdr));
	601	skb_reset_transport_header(skb);
84ca5e03	602	memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head);
8df8c56a JR	603	skb_reset_network_header(skb);
8df8c56a JR	604
84ca5e03	605	pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len);
8df8c56a JR	606
8df8c56a JR	607	raw_dump_table(__func__, "raw skb data dump compressed",
4710d806	608	skb->data, skb->len);
8df8c56a JR	609	return 0;
	610	}
	611	EXPORT_SYMBOL_GPL(lowpan_header_compress);