These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

6 files changed, 567 insertions, 252 deletions

diff --git a/kernel/net/6lowpan/Makefile b/kernel/net/6lowpan/Makefile
index eb8baa72a..c6ffc55ee 100644
--- a/kernel/net/6lowpan/Makefile
+++ b/kernel/net/6lowpan/Makefile
@@ -1,6 +1,6 @@
 obj-$(CONFIG_6LOWPAN) += 6lowpan.o
 
-6lowpan-y := iphc.o nhc.o
+6lowpan-y := core.o iphc.o nhc.o
 
 #rfc6282 nhcs
 obj-$(CONFIG_6LOWPAN_NHC_DEST) += nhc_dest.o
diff --git a/kernel/net/6lowpan/core.c b/kernel/net/6lowpan/core.c
new file mode 100644
index 000000000..83b19e072
--- /dev/null
+++ b/kernel/net/6lowpan/core.c
@@ -0,0 +1,45 @@
+/* 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.
+ *
+ * Authors:
+ * (C) 2015 Pengutronix, Alexander Aring <aar@pengutronix.de>
+ */
+
+#include <linux/module.h>
+
+#include <net/6lowpan.h>
+
+void lowpan_netdev_setup(struct net_device *dev, enum lowpan_lltypes lltype)
+{
+	dev->addr_len = EUI64_ADDR_LEN;
+	dev->type = ARPHRD_6LOWPAN;
+	dev->mtu = IPV6_MIN_MTU;
+	dev->priv_flags |= IFF_NO_QUEUE;
+
+	lowpan_priv(dev)->lltype = lltype;
+}
+EXPORT_SYMBOL(lowpan_netdev_setup);
+
+static int __init lowpan_module_init(void)
+{
+	request_module_nowait("ipv6");
+
+	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");
diff --git a/kernel/net/6lowpan/iphc.c b/kernel/net/6lowpan/iphc.c
index 94a375c04..346b5c1a9 100644
--- a/kernel/net/6lowpan/iphc.c
+++ b/kernel/net/6lowpan/iphc.c
@@ -48,38 +48,179 @@
 
 #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>
+
+/* special link-layer handling */
+#include <net/mac802154.h>
 
 #include "nhc.h"
 
+/* Values of fields within the IPHC encoding first byte */
+#define LOWPAN_IPHC_TF_MASK	0x18
+#define LOWPAN_IPHC_TF_00	0x00
+#define LOWPAN_IPHC_TF_01	0x08
+#define LOWPAN_IPHC_TF_10	0x10
+#define LOWPAN_IPHC_TF_11	0x18
+
+#define LOWPAN_IPHC_NH		0x04
+
+#define LOWPAN_IPHC_HLIM_MASK	0x03
+#define LOWPAN_IPHC_HLIM_00	0x00
+#define LOWPAN_IPHC_HLIM_01	0x01
+#define LOWPAN_IPHC_HLIM_10	0x02
+#define LOWPAN_IPHC_HLIM_11	0x03
+
+/* Values of fields within the IPHC encoding second byte */
+#define LOWPAN_IPHC_CID		0x80
+
+#define LOWPAN_IPHC_SAC		0x40
+
+#define LOWPAN_IPHC_SAM_MASK	0x30
+#define LOWPAN_IPHC_SAM_00	0x00
+#define LOWPAN_IPHC_SAM_01	0x10
+#define LOWPAN_IPHC_SAM_10	0x20
+#define LOWPAN_IPHC_SAM_11	0x30
+
+#define LOWPAN_IPHC_M		0x08
+
+#define LOWPAN_IPHC_DAC		0x04
+
+#define LOWPAN_IPHC_DAM_MASK	0x03
+#define LOWPAN_IPHC_DAM_00	0x00
+#define LOWPAN_IPHC_DAM_01	0x01
+#define LOWPAN_IPHC_DAM_10	0x02
+#define LOWPAN_IPHC_DAM_11	0x03
+
+/* ipv6 address based on mac
+ * second bit-flip (Universe/Local) is done according RFC2464
+ */
+#define is_addr_mac_addr_based(a, m) \
+	((((a)->s6_addr[8])  == (((m)[0]) ^ 0x02)) &&	\
+	 (((a)->s6_addr[9])  == (m)[1]) &&		\
+	 (((a)->s6_addr[10]) == (m)[2]) &&		\
+	 (((a)->s6_addr[11]) == (m)[3]) &&		\
+	 (((a)->s6_addr[12]) == (m)[4]) &&		\
+	 (((a)->s6_addr[13]) == (m)[5]) &&		\
+	 (((a)->s6_addr[14]) == (m)[6]) &&		\
+	 (((a)->s6_addr[15]) == (m)[7]))
+
+/* check whether we can compress the IID to 16 bits,
+ * it's possible for unicast addresses with first 49 bits are zero only.
+ */
+#define lowpan_is_iid_16_bit_compressable(a)	\
+	((((a)->s6_addr16[4]) == 0) &&		\
+	 (((a)->s6_addr[10]) == 0) &&		\
+	 (((a)->s6_addr[11]) == 0xff) &&	\
+	 (((a)->s6_addr[12]) == 0xfe) &&	\
+	 (((a)->s6_addr[13]) == 0))
+
+/* check whether the 112-bit gid of the multicast address is mappable to: */
+
+/* 48 bits, FFXX::00XX:XXXX:XXXX */
+#define lowpan_is_mcast_addr_compressable48(a)	\
+	((((a)->s6_addr16[1]) == 0) &&		\
+	 (((a)->s6_addr16[2]) == 0) &&		\
+	 (((a)->s6_addr16[3]) == 0) &&		\
+	 (((a)->s6_addr16[4]) == 0) &&		\
+	 (((a)->s6_addr[10]) == 0))
+
+/* 32 bits, FFXX::00XX:XXXX */
+#define lowpan_is_mcast_addr_compressable32(a)	\
+	((((a)->s6_addr16[1]) == 0) &&		\
+	 (((a)->s6_addr16[2]) == 0) &&		\
+	 (((a)->s6_addr16[3]) == 0) &&		\
+	 (((a)->s6_addr16[4]) == 0) &&		\
+	 (((a)->s6_addr16[5]) == 0) &&		\
+	 (((a)->s6_addr[12]) == 0))
+
+/* 8 bits, FF02::00XX */
+#define lowpan_is_mcast_addr_compressable8(a)	\
+	((((a)->s6_addr[1])  == 2) &&		\
+	 (((a)->s6_addr16[1]) == 0) &&		\
+	 (((a)->s6_addr16[2]) == 0) &&		\
+	 (((a)->s6_addr16[3]) == 0) &&		\
+	 (((a)->s6_addr16[4]) == 0) &&		\
+	 (((a)->s6_addr16[5]) == 0) &&		\
+	 (((a)->s6_addr16[6]) == 0) &&		\
+	 (((a)->s6_addr[14]) == 0))
+
+static inline void iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
+						const void *lladdr)
+{
+	/* fe:80::XXXX:XXXX:XXXX:XXXX
+	 *        \_________________/
+	 *              hwaddr
+	 */
+	ipaddr->s6_addr[0] = 0xFE;
+	ipaddr->s6_addr[1] = 0x80;
+	memcpy(&ipaddr->s6_addr[8], lladdr, EUI64_ADDR_LEN);
+	/* second bit-flip (Universe/Local)
+	 * is done according RFC2464
+	 */
+	ipaddr->s6_addr[8] ^= 0x02;
+}
+
+static inline void iphc_uncompress_802154_lladdr(struct in6_addr *ipaddr,
+						 const void *lladdr)
+{
+	const struct ieee802154_addr *addr = lladdr;
+	u8 eui64[EUI64_ADDR_LEN] = { };
+
+	switch (addr->mode) {
+	case IEEE802154_ADDR_LONG:
+		ieee802154_le64_to_be64(eui64, &addr->extended_addr);
+		iphc_uncompress_eui64_lladdr(ipaddr, eui64);
+		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;
+		ieee802154_le16_to_be16(&ipaddr->s6_addr16[7],
+					&addr->short_addr);
+		break;
+	default:
+		/* should never handled and filtered by 802154 6lowpan */
+		WARN_ON_ONCE(1);
+		break;
+	}
+}
+
 /* Uncompress address function for source and
  * destination address(non-multicast).
  *
- * address_mode is sam value or dam value.
+ * address_mode is the masked value for sam 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)
+static int uncompress_addr(struct sk_buff *skb, const struct net_device *dev,
+			   struct in6_addr *ipaddr, u8 address_mode,
+			   const void *lladdr)
 {
 	bool fail;
 
 	switch (address_mode) {
-	case LOWPAN_IPHC_ADDR_00:
+	/* SAM and DAM are the same here */
+	case LOWPAN_IPHC_DAM_00:
 		/* for global link addresses */
 		fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
 		break;
-	case LOWPAN_IPHC_ADDR_01:
+	case LOWPAN_IPHC_SAM_01:
+	case LOWPAN_IPHC_DAM_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:
+	case LOWPAN_IPHC_SAM_10:
+	case LOWPAN_IPHC_DAM_10:
 		/* fe:80::ff:fe00:XXXX */
 		ipaddr->s6_addr[0] = 0xFE;
 		ipaddr->s6_addr[1] = 0x80;
@@ -87,38 +228,16 @@ static int uncompress_addr(struct sk_buff *skb,
 		ipaddr->s6_addr[12] = 0xFE;
 		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
 		break;
-	case LOWPAN_IPHC_ADDR_03:
+	case LOWPAN_IPHC_SAM_11:
+	case LOWPAN_IPHC_DAM_11:
 		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));
+		switch (lowpan_priv(dev)->lltype) {
+		case LOWPAN_LLTYPE_IEEE802154:
+			iphc_uncompress_802154_lladdr(ipaddr, lladdr);
 			break;
 		default:
-			pr_debug("Invalid addr_type set\n");
-			return -EINVAL;
+			iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
+			break;
 		}
 		break;
 	default:
@@ -142,24 +261,25 @@ static int uncompress_addr(struct sk_buff *skb,
  */
 static int uncompress_context_based_src_addr(struct sk_buff *skb,
 					     struct in6_addr *ipaddr,
-					     const u8 sam)
+					     u8 address_mode)
 {
-	switch (sam) {
-	case LOWPAN_IPHC_ADDR_00:
+	switch (address_mode) {
+	case LOWPAN_IPHC_SAM_00:
 		/* unspec address ::
 		 * Do nothing, address is already ::
 		 */
 		break;
-	case LOWPAN_IPHC_ADDR_01:
+	case LOWPAN_IPHC_SAM_01:
 		/* TODO */
-	case LOWPAN_IPHC_ADDR_02:
+	case LOWPAN_IPHC_SAM_10:
 		/* TODO */
-	case LOWPAN_IPHC_ADDR_03:
+	case LOWPAN_IPHC_SAM_11:
 		/* TODO */
-		netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
+		netdev_warn(skb->dev, "SAM value 0x%x not supported\n",
+			    address_mode);
 		return -EINVAL;
 	default:
-		pr_debug("Invalid sam value: 0x%x\n", sam);
+		pr_debug("Invalid sam value: 0x%x\n", address_mode);
 		return -EINVAL;
 	}
 
@@ -175,11 +295,11 @@ static int uncompress_context_based_src_addr(struct sk_buff *skb,
  */
 static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 					     struct in6_addr *ipaddr,
-					     const u8 dam)
+					     u8 address_mode)
 {
 	bool fail;
 
-	switch (dam) {
+	switch (address_mode) {
 	case LOWPAN_IPHC_DAM_00:
 		/* 00:  128 bits.  The full address
 		 * is carried in-line.
@@ -211,7 +331,7 @@ static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
 		break;
 	default:
-		pr_debug("DAM value has a wrong value: 0x%x\n", dam);
+		pr_debug("DAM value has a wrong value: 0x%x\n", address_mode);
 		return -EINVAL;
 	}
 
@@ -226,77 +346,142 @@ static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
 	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)
+/* get the ecn values from iphc tf format and set it to ipv6hdr */
+static inline void lowpan_iphc_tf_set_ecn(struct ipv6hdr *hdr, const u8 *tf)
 {
-	struct ipv6hdr hdr = {};
-	u8 tmp, num_context = 0;
-	int err;
+	/* get the two higher bits which is ecn */
+	u8 ecn = tf[0] & 0xc0;
 
-	raw_dump_table(__func__, "raw skb data dump uncompressed",
-		       skb->data, skb->len);
+	/* ECN takes 0x30 in hdr->flow_lbl[0] */
+	hdr->flow_lbl[0] |= (ecn >> 2);
+}
 
-	/* 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;
-	}
+/* get the dscp values from iphc tf format and set it to ipv6hdr */
+static inline void lowpan_iphc_tf_set_dscp(struct ipv6hdr *hdr, const u8 *tf)
+{
+	/* DSCP is at place after ECN */
+	u8 dscp = tf[0] & 0x3f;
 
-	hdr.version = 6;
+	/* The four highest bits need to be set at hdr->priority */
+	hdr->priority |= ((dscp & 0x3c) >> 2);
+	/* The two lower bits is part of hdr->flow_lbl[0] */
+	hdr->flow_lbl[0] |= ((dscp & 0x03) << 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)
+/* get the flow label values from iphc tf format and set it to ipv6hdr */
+static inline void lowpan_iphc_tf_set_lbl(struct ipv6hdr *hdr, const u8 *lbl)
+{
+	/* flow label is always some array started with lower nibble of
+	 * flow_lbl[0] and followed with two bytes afterwards. Inside inline
+	 * data the flow_lbl position can be different, which will be handled
+	 * by lbl pointer. E.g. case "01" vs "00" the traffic class is 8 bit
+	 * shifted, the different lbl pointer will handle that.
+	 *
+	 * The flow label will started at lower nibble of flow_lbl[0], the
+	 * higher nibbles are part of DSCP + ECN.
 	 */
-	case 0: /* 00b */
-		if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
+	hdr->flow_lbl[0] |= lbl[0] & 0x0f;
+	memcpy(&hdr->flow_lbl[1], &lbl[1], 2);
+}
+
+/* lowpan_iphc_tf_decompress - decompress the traffic class.
+ *	This function will return zero on success, a value lower than zero if
+ *	failed.
+ */
+static int lowpan_iphc_tf_decompress(struct sk_buff *skb, struct ipv6hdr *hdr,
+				     u8 val)
+{
+	u8 tf[4];
+
+	/* Traffic Class and Flow Label */
+	switch (val) {
+	case LOWPAN_IPHC_TF_00:
+		/* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) */
+		if (lowpan_fetch_skb(skb, tf, 4))
 			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);
+		/*                      1                   2                   3
+		 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+		 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+		 * |ECN|   DSCP    |  rsv  |             Flow Label                |
+		 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+		 */
+		lowpan_iphc_tf_set_ecn(hdr, tf);
+		lowpan_iphc_tf_set_dscp(hdr, tf);
+		lowpan_iphc_tf_set_lbl(hdr, &tf[1]);
 		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)))
+	case LOWPAN_IPHC_TF_01:
+		/* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided. */
+		if (lowpan_fetch_skb(skb, tf, 3))
 			return -EINVAL;
 
-		hdr.priority = ((tmp >> 2) & 0x0f);
-		hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
+		/*                     1                   2
+		 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+		 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+		 * |ECN|rsv|             Flow Label                |
+		 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+		 */
+		lowpan_iphc_tf_set_ecn(hdr, tf);
+		lowpan_iphc_tf_set_lbl(hdr, &tf[0]);
 		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)))
+	case LOWPAN_IPHC_TF_10:
+		/* ECN + DSCP (1 byte), Flow Label is elided. */
+		if (lowpan_fetch_skb(skb, tf, 1))
 			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);
+		/*  0 1 2 3 4 5 6 7
+		 * +-+-+-+-+-+-+-+-+
+		 * |ECN|   DSCP    |
+		 * +-+-+-+-+-+-+-+-+
+		 */
+		lowpan_iphc_tf_set_ecn(hdr, tf);
+		lowpan_iphc_tf_set_dscp(hdr, tf);
 		break;
-	/* Traffic Class and Flow Label are elided */
-	case 3: /* 11b */
+	case LOWPAN_IPHC_TF_11:
+		/* Traffic Class and Flow Label are elided */
 		break;
 	default:
-		break;
+		WARN_ON_ONCE(1);
+		return -EINVAL;
 	}
 
+	return 0;
+}
+
+/* TTL uncompression values */
+static const u8 lowpan_ttl_values[] = {
+	[LOWPAN_IPHC_HLIM_01] = 1,
+	[LOWPAN_IPHC_HLIM_10] = 64,
+	[LOWPAN_IPHC_HLIM_11] = 255,
+};
+
+int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
+			     const void *daddr, const void *saddr)
+{
+	struct ipv6hdr hdr = {};
+	u8 iphc0, iphc1;
+	int err;
+
+	raw_dump_table(__func__, "raw skb data dump uncompressed",
+		       skb->data, skb->len);
+
+	if (lowpan_fetch_skb(skb, &iphc0, sizeof(iphc0)) ||
+	    lowpan_fetch_skb(skb, &iphc1, sizeof(iphc1)))
+		return -EINVAL;
+
+	/* another if the CID flag is set */
+	if (iphc1 & LOWPAN_IPHC_CID)
+		return -ENOTSUPP;
+
+	hdr.version = 6;
+
+	err = lowpan_iphc_tf_decompress(skb, &hdr,
+					iphc0 & LOWPAN_IPHC_TF_MASK);
+	if (err < 0)
+		return err;
+
 	/* Next Header */
-	if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
+	if (!(iphc0 & LOWPAN_IPHC_NH)) {
 		/* Next header is carried inline */
 		if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
 			return -EINVAL;
@@ -306,35 +491,30 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
 	}
 
 	/* Hop Limit */
-	if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) {
-		hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
+	if ((iphc0 & LOWPAN_IPHC_HLIM_MASK) != LOWPAN_IPHC_HLIM_00) {
+		hdr.hop_limit = lowpan_ttl_values[iphc0 & LOWPAN_IPHC_HLIM_MASK];
 	} 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);
+		err = uncompress_context_based_src_addr(skb, &hdr.saddr,
+							iphc1 & LOWPAN_IPHC_SAM_MASK);
 	} else {
 		/* Source address uncompression */
 		pr_debug("source address stateless compression\n");
-		err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
-				      saddr_type, saddr_len);
+		err = uncompress_addr(skb, dev, &hdr.saddr,
+				      iphc1 & LOWPAN_IPHC_SAM_MASK, saddr);
 	}
 
 	/* 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) {
@@ -342,22 +522,22 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
 			/* TODO: implement this */
 		} else {
 			err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
-								tmp);
+								iphc1 & LOWPAN_IPHC_DAM_MASK);
 
 			if (err)
 				return -EINVAL;
 		}
 	} else {
-		err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
-				      daddr_type, daddr_len);
+		err = uncompress_addr(skb, dev, &hdr.daddr,
+				      iphc1 & LOWPAN_IPHC_DAM_MASK, daddr);
 		pr_debug("dest: stateless compression mode %d dest %pI6c\n",
-			 tmp, &hdr.daddr);
+			 iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
 		if (err)
 			return -EINVAL;
 	}
 
 	/* Next header data uncompression */
-	if (iphc0 & LOWPAN_IPHC_NH_C) {
+	if (iphc0 & LOWPAN_IPHC_NH) {
 		err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
 		if (err < 0)
 			return err;
@@ -367,7 +547,18 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
 			return err;
 	}
 
-	hdr.payload_len = htons(skb->len);
+	switch (lowpan_priv(dev)->lltype) {
+	case LOWPAN_LLTYPE_IEEE802154:
+		if (lowpan_802154_cb(skb)->d_size)
+			hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -
+						sizeof(struct ipv6hdr));
+		else
+			hdr.payload_len = htons(skb->len);
+		break;
+	default:
+		hdr.payload_len = htons(skb->len);
+		break;
+	}
 
 	pr_debug("skb headroom size = %d, data length = %d\n",
 		 skb_headroom(skb), skb->len);
@@ -387,42 +578,176 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
 }
 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)
+static const u8 lowpan_iphc_dam_to_sam_value[] = {
+	[LOWPAN_IPHC_DAM_00] = LOWPAN_IPHC_SAM_00,
+	[LOWPAN_IPHC_DAM_01] = LOWPAN_IPHC_SAM_01,
+	[LOWPAN_IPHC_DAM_10] = LOWPAN_IPHC_SAM_10,
+	[LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
+};
+
+static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct in6_addr *ipaddr,
+				  const unsigned char *lladdr, bool sam)
 {
-	u8 val = 0;
+	u8 dam = LOWPAN_IPHC_DAM_00;
 
 	if (is_addr_mac_addr_based(ipaddr, lladdr)) {
-		val = 3; /* 0-bits */
+		dam = LOWPAN_IPHC_DAM_11; /* 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 */
+		dam = LOWPAN_IPHC_DAM_10; /* 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 */
+		dam = LOWPAN_IPHC_DAM_01; /* 64-bits */
 		raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
 				*hc_ptr - 8, 8);
 	}
 
-	return rol8(val, shift);
+	if (sam)
+		return lowpan_iphc_dam_to_sam_value[dam];
+	else
+		return dam;
+}
+
+/* lowpan_iphc_get_tc - get the ECN + DCSP fields in hc format */
+static inline u8 lowpan_iphc_get_tc(const struct ipv6hdr *hdr)
+{
+	u8 dscp, ecn;
+
+	/* hdr->priority contains the higher bits of dscp, lower are part of
+	 * flow_lbl[0]. Note ECN, DCSP is swapped in ipv6 hdr.
+	 */
+	dscp = (hdr->priority << 2) | ((hdr->flow_lbl[0] & 0xc0) >> 6);
+	/* ECN is at the two lower bits from first nibble of flow_lbl[0] */
+	ecn = (hdr->flow_lbl[0] & 0x30);
+	/* for pretty debug output, also shift ecn to get the ecn value */
+	pr_debug("ecn 0x%02x dscp 0x%02x\n", ecn >> 4, dscp);
+	/* ECN is at 0x30 now, shift it to have ECN + DCSP */
+	return (ecn << 2) | dscp;
+}
+
+/* lowpan_iphc_is_flow_lbl_zero - check if flow label is zero */
+static inline bool lowpan_iphc_is_flow_lbl_zero(const struct ipv6hdr *hdr)
+{
+	return ((!(hdr->flow_lbl[0] & 0x0f)) &&
+		!hdr->flow_lbl[1] && !hdr->flow_lbl[2]);
+}
+
+/* lowpan_iphc_tf_compress - compress the traffic class which is set by
+ *	ipv6hdr. Return the corresponding format identifier which is used.
+ */
+static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
+{
+	/* get ecn dscp data in a byteformat as: ECN(hi) + DSCP(lo) */
+	u8 tc = lowpan_iphc_get_tc(hdr), tf[4], val;
+
+	/* printout the traffic class in hc format */
+	pr_debug("tc 0x%02x\n", tc);
+
+	if (lowpan_iphc_is_flow_lbl_zero(hdr)) {
+		if (!tc) {
+			/* 11:  Traffic Class and Flow Label are elided. */
+			val = LOWPAN_IPHC_TF_11;
+		} else {
+			/* 10:  ECN + DSCP (1 byte), Flow Label is elided.
+			 *
+			 *  0 1 2 3 4 5 6 7
+			 * +-+-+-+-+-+-+-+-+
+			 * |ECN|   DSCP    |
+			 * +-+-+-+-+-+-+-+-+
+			 */
+			lowpan_push_hc_data(hc_ptr, &tc, sizeof(tc));
+			val = LOWPAN_IPHC_TF_10;
+		}
+	} else {
+		/* check if dscp is zero, it's after the first two bit */
+		if (!(tc & 0x3f)) {
+			/* 01:  ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
+			 *
+			 *                     1                   2
+			 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+			 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+			 * |ECN|rsv|             Flow Label                |
+			 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+			 */
+			memcpy(&tf[0], &hdr->flow_lbl[0], 3);
+			/* zero the highest 4-bits, contains DCSP + ECN */
+			tf[0] &= ~0xf0;
+			/* set ECN */
+			tf[0] |= (tc & 0xc0);
+
+			lowpan_push_hc_data(hc_ptr, tf, 3);
+			val = LOWPAN_IPHC_TF_01;
+		} else {
+			/* 00:  ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
+			 *
+			 *                      1                   2                   3
+			 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+			 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+			 * |ECN|   DSCP    |  rsv  |             Flow Label                |
+			 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+			 */
+			memcpy(&tf[0], &tc, sizeof(tc));
+			/* highest nibble of flow_lbl[0] is part of DSCP + ECN
+			 * which will be the 4-bit pad and will be filled with
+			 * zeros afterwards.
+			 */
+			memcpy(&tf[1], &hdr->flow_lbl[0], 3);
+			/* zero the 4-bit pad, which is reserved */
+			tf[1] &= ~0xf0;
+
+			lowpan_push_hc_data(hc_ptr, tf, 4);
+			val = LOWPAN_IPHC_TF_00;
+		}
+	}
+
+	return val;
 }
 
-int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
-			   unsigned short type, const void *_daddr,
-			   const void *_saddr, unsigned int len)
+static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
+					  const struct in6_addr *ipaddr)
 {
-	u8 tmp, iphc0, iphc1, *hc_ptr;
+	u8 val;
+
+	if (lowpan_is_mcast_addr_compressable8(ipaddr)) {
+		pr_debug("compressed to 1 octet\n");
+		/* use last byte */
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[15], 1);
+		val = LOWPAN_IPHC_DAM_11;
+	} else if (lowpan_is_mcast_addr_compressable32(ipaddr)) {
+		pr_debug("compressed to 4 octets\n");
+		/* second byte + the last three */
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[13], 3);
+		val = LOWPAN_IPHC_DAM_10;
+	} else if (lowpan_is_mcast_addr_compressable48(ipaddr)) {
+		pr_debug("compressed to 6 octets\n");
+		/* second byte + the last five */
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[11], 5);
+		val = LOWPAN_IPHC_DAM_01;
+	} else {
+		pr_debug("using full address\n");
+		lowpan_push_hc_data(hc_ptr, ipaddr->s6_addr, 16);
+		val = LOWPAN_IPHC_DAM_00;
+	}
+
+	return val;
+}
+
+int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
+			   const void *daddr, const void *saddr)
+{
+	u8 iphc0, iphc1, *hc_ptr;
 	struct ipv6hdr *hdr;
-	u8 head[100] = {};
+	u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
 	int ret, addr_type;
 
-	if (type != ETH_P_IPV6)
+	if (skb->protocol != htons(ETH_P_IPV6))
 		return -EINVAL;
 
 	hdr = ipv6_hdr(skb);
@@ -446,63 +771,26 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
 
 	/* 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_inline(__func__, "saddr", saddr, EUI64_ADDR_LEN);
+	raw_dump_inline(__func__, "daddr", daddr, EUI64_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;
-		}
-	}
+	/* Traffic Class, Flow Label compression */
+	iphc0 |= lowpan_iphc_tf_compress(&hc_ptr, hdr);
 
 	/* 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;
+	ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr);
+	if (ret == -ENOENT)
+		lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
+				    sizeof(hdr->nexthdr));
+	else
+		iphc0 |= LOWPAN_IPHC_NH;
 
 	/* Hop limit
 	 * if 1:   compress, encoding is 01
@@ -512,13 +800,13 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
 	 */
 	switch (hdr->hop_limit) {
 	case 1:
-		iphc0 |= LOWPAN_IPHC_TTL_1;
+		iphc0 |= LOWPAN_IPHC_HLIM_01;
 		break;
 	case 64:
-		iphc0 |= LOWPAN_IPHC_TTL_64;
+		iphc0 |= LOWPAN_IPHC_HLIM_10;
 		break;
 	case 255:
-		iphc0 |= LOWPAN_IPHC_TTL_255;
+		iphc0 |= LOWPAN_IPHC_HLIM_11;
 		break;
 	default:
 		lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
@@ -532,9 +820,8 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
 		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);
+			iphc1 |= lowpan_compress_addr_64(&hc_ptr, &hdr->saddr,
+							 saddr, true);
 			pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
 				 &hdr->saddr, iphc1);
 		} else {
@@ -548,38 +835,12 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
 	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);
-		}
+		iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr, &hdr->daddr);
 	} else {
 		if (addr_type & IPV6_ADDR_LINKLOCAL) {
 			/* TODO: context lookup */
-			iphc1 |= lowpan_compress_addr_64(&hc_ptr,
-				LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr);
+			iphc1 |= lowpan_compress_addr_64(&hc_ptr, &hdr->daddr,
+							 daddr, false);
 			pr_debug("dest address unicast link-local %pI6c "
 				 "iphc1 0x%02x\n", &hdr->daddr, iphc1);
 		} else {
@@ -589,7 +850,7 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
 	}
 
 	/* next header compression */
-	if (iphc0 & LOWPAN_IPHC_NH_C) {
+	if (iphc0 & LOWPAN_IPHC_NH) {
 		ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
 		if (ret < 0)
 			return ret;
@@ -610,19 +871,3 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
 	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");
diff --git a/kernel/net/6lowpan/nhc.c b/kernel/net/6lowpan/nhc.c
index fd20fc51a..7008d53e4 100644
--- a/kernel/net/6lowpan/nhc.c
+++ b/kernel/net/6lowpan/nhc.c
@@ -95,23 +95,20 @@ static struct lowpan_nhc *lowpan_nhc_by_nhcid(const struct sk_buff *skb)
 }
 
 int lowpan_nhc_check_compression(struct sk_buff *skb,
-				 const struct ipv6hdr *hdr, u8 **hc_ptr,
-				 u8 *iphc0)
+				 const struct ipv6hdr *hdr, u8 **hc_ptr)
 {
 	struct lowpan_nhc *nhc;
+	int ret = 0;
 
 	spin_lock_bh(&lowpan_nhc_lock);
 
 	nhc = lowpan_nexthdr_nhcs[hdr->nexthdr];
-	if (nhc && nhc->compress)
-		*iphc0 |= LOWPAN_IPHC_NH_C;
-	else
-		lowpan_push_hc_data(hc_ptr, &hdr->nexthdr,
-				    sizeof(hdr->nexthdr));
+	if (!(nhc && nhc->compress))
+		ret = -ENOENT;
 
 	spin_unlock_bh(&lowpan_nhc_lock);
 
-	return 0;
+	return ret;
 }
 
 int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
@@ -157,7 +154,8 @@ out:
 	return ret;
 }
 
-int lowpan_nhc_do_uncompression(struct sk_buff *skb, struct net_device *dev,
+int lowpan_nhc_do_uncompression(struct sk_buff *skb,
+				const struct net_device *dev,
 				struct ipv6hdr *hdr)
 {
 	struct lowpan_nhc *nhc;
diff --git a/kernel/net/6lowpan/nhc.h b/kernel/net/6lowpan/nhc.h
index ed44938eb..803041400 100644
--- a/kernel/net/6lowpan/nhc.h
+++ b/kernel/net/6lowpan/nhc.h
@@ -8,8 +8,6 @@
 #include <net/6lowpan.h>
 #include <net/ipv6.h>
 
-#define LOWPAN_NHC_MAX_ID_LEN	1
-
 /**
  * LOWPAN_NHC - helper macro to generate nh id fields and lowpan_nhc struct
  *
@@ -88,19 +86,16 @@ struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr);
 
 /**
  * lowpan_nhc_check_compression - checks if we support compression format. If
- *	we support the nhc by nexthdr field, the 6LoWPAN iphc NHC bit will be
- *	set. If we don't support nexthdr will be added as inline data to the
- *	6LoWPAN header.
+ *	we support the nhc by nexthdr field, the function will return 0. If we
+ *	don't support the nhc by nexthdr this function will return -ENOENT.
  *
  * @skb: skb of 6LoWPAN header to read nhc and replace header.
  * @hdr: ipv6hdr to check the nexthdr value
  * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
  *	    replaced header.
- * @iphc0: iphc0 pointer to set the 6LoWPAN NHC bit
  */
 int lowpan_nhc_check_compression(struct sk_buff *skb,
-				 const struct ipv6hdr *hdr, u8 **hc_ptr,
-				 u8 *iphc0);
+				 const struct ipv6hdr *hdr, u8 **hc_ptr);
 
 /**
  * lowpan_nhc_do_compression - calling compress callback for nhc
@@ -121,7 +116,8 @@ int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
  * @dev: netdevice for print logging information.
  * @hdr: ipv6hdr for setting nexthdr value.
  */
-int lowpan_nhc_do_uncompression(struct sk_buff *skb, struct net_device *dev,
+int lowpan_nhc_do_uncompression(struct sk_buff *skb,
+				const struct net_device *dev,
 				struct ipv6hdr *hdr);
 
 /**
diff --git a/kernel/net/6lowpan/nhc_udp.c b/kernel/net/6lowpan/nhc_udp.c
index c6bcaeb42..69537a2ea 100644
--- a/kernel/net/6lowpan/nhc_udp.c
+++ b/kernel/net/6lowpan/nhc_udp.c
@@ -17,7 +17,27 @@
 
 #include "nhc.h"
 
-#define LOWPAN_NHC_UDP_IDLEN	1
+#define LOWPAN_NHC_UDP_MASK		0xF8
+#define LOWPAN_NHC_UDP_ID		0xF0
+#define LOWPAN_NHC_UDP_IDLEN		1
+
+#define LOWPAN_NHC_UDP_4BIT_PORT	0xF0B0
+#define LOWPAN_NHC_UDP_4BIT_MASK	0xFFF0
+#define LOWPAN_NHC_UDP_8BIT_PORT	0xF000
+#define LOWPAN_NHC_UDP_8BIT_MASK	0xFF00
+
+/* values for port compression, _with checksum_ ie bit 5 set to 0 */
+
+/* all inline */
+#define LOWPAN_NHC_UDP_CS_P_00	0xF0
+/* source 16bit inline, dest = 0xF0 + 8 bit inline */
+#define LOWPAN_NHC_UDP_CS_P_01	0xF1
+/* source = 0xF0 + 8bit inline, dest = 16 bit inline */
+#define LOWPAN_NHC_UDP_CS_P_10	0xF2
+/* source & dest = 0xF0B + 4bit inline */
+#define LOWPAN_NHC_UDP_CS_P_11	0xF3
+/* checksum elided */
+#define LOWPAN_NHC_UDP_CS_C	0x04
 
 static int udp_uncompress(struct sk_buff *skb, size_t needed)
 {
@@ -71,7 +91,18 @@ static int udp_uncompress(struct sk_buff *skb, size_t needed)
 	 * here, we obtain the hint from the remaining size of the
 	 * frame
 	 */
-	uh.len = htons(skb->len + sizeof(struct udphdr));
+	switch (lowpan_priv(skb->dev)->lltype) {
+	case LOWPAN_LLTYPE_IEEE802154:
+		if (lowpan_802154_cb(skb)->d_size)
+			uh.len = htons(lowpan_802154_cb(skb)->d_size -
+				       sizeof(struct ipv6hdr));
+		else
+			uh.len = htons(skb->len + sizeof(struct udphdr));
+		break;
+	default:
+		uh.len = htons(skb->len + sizeof(struct udphdr));
+		break;
+	}
 	pr_debug("uncompressed UDP length: src = %d", ntohs(uh.len));
 
 	/* replace the compressed UDP head by the uncompressed UDP