Initial import

1 files changed, 628 insertions, 0 deletions

diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
new file mode 100644
index 000000000..94a375c04
--- /dev/null
+++ b/net/6lowpan/iphc.c
@@ -0,0 +1,628 @@
+/*
+ * 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/module.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] = (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");