Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

22 files changed, 3004 insertions, 0 deletions

diff --git a/net/6lowpan/6lowpan_i.h b/net/6lowpan/6lowpan_i.h
new file mode 100644
index 000000000..01853cec0
--- /dev/null
+++ b/net/6lowpan/6lowpan_i.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __6LOWPAN_I_H
+#define __6LOWPAN_I_H
+
+#include <linux/netdevice.h>
+
+#include <net/6lowpan.h>
+
+/* caller need to be sure it's dev->type is ARPHRD_6LOWPAN */
+static inline bool lowpan_is_ll(const struct net_device *dev,
+				enum lowpan_lltypes lltype)
+{
+	return lowpan_dev(dev)->lltype == lltype;
+}
+
+extern const struct ndisc_ops lowpan_ndisc_ops;
+
+int addrconf_ifid_802154_6lowpan(u8 *eui, struct net_device *dev);
+
+#ifdef CONFIG_6LOWPAN_DEBUGFS
+void lowpan_dev_debugfs_init(struct net_device *dev);
+void lowpan_dev_debugfs_exit(struct net_device *dev);
+
+void __init lowpan_debugfs_init(void);
+void lowpan_debugfs_exit(void);
+#else
+static inline void lowpan_dev_debugfs_init(struct net_device *dev) { }
+static inline void lowpan_dev_debugfs_exit(struct net_device *dev) { }
+
+static inline void __init lowpan_debugfs_init(void) { }
+static inline void lowpan_debugfs_exit(void) { }
+#endif /* CONFIG_6LOWPAN_DEBUGFS */
+
+#endif /* __6LOWPAN_I_H */
diff --git a/net/6lowpan/Kconfig b/net/6lowpan/Kconfig
new file mode 100644
index 000000000..d8fc45949
--- /dev/null
+++ b/net/6lowpan/Kconfig
@@ -0,0 +1,105 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menuconfig 6LOWPAN
+	tristate "6LoWPAN Support"
+	depends on IPV6
+	help
+	  This enables IPv6 over Low power Wireless Personal Area Network -
+	  "6LoWPAN" which is supported by IEEE 802.15.4 or Bluetooth stacks.
+
+config 6LOWPAN_DEBUGFS
+	bool "6LoWPAN debugfs support"
+	depends on 6LOWPAN
+	depends on DEBUG_FS
+	help
+	  This enables 6LoWPAN debugfs support. For example to manipulate
+	  IPHC context information at runtime.
+
+menuconfig 6LOWPAN_NHC
+	tristate "Next Header and Generic Header Compression Support"
+	depends on 6LOWPAN
+	default y
+	help
+	  Support for next header and generic header compression defined in
+	  RFC6282 and RFC7400.
+
+if 6LOWPAN_NHC
+
+config 6LOWPAN_NHC_DEST
+	tristate "Destination Options Header Support"
+	default y
+	help
+	  6LoWPAN IPv6 Destination Options Header compression according to
+	  RFC6282.
+
+config 6LOWPAN_NHC_FRAGMENT
+	tristate "Fragment Header Support"
+	default y
+	help
+	  6LoWPAN IPv6 Fragment Header compression according to RFC6282.
+
+config 6LOWPAN_NHC_HOP
+	tristate "Hop-by-Hop Options Header Support"
+	default y
+	help
+	  6LoWPAN IPv6 Hop-by-Hop Options Header compression according to
+	  RFC6282.
+
+config 6LOWPAN_NHC_IPV6
+	tristate "IPv6 Header Support"
+	default y
+	help
+	  6LoWPAN IPv6 Header compression according to RFC6282.
+
+config 6LOWPAN_NHC_MOBILITY
+	tristate "Mobility Header Support"
+	default y
+	help
+	  6LoWPAN IPv6 Mobility Header compression according to RFC6282.
+
+config 6LOWPAN_NHC_ROUTING
+	tristate "Routing Header Support"
+	default y
+	help
+	  6LoWPAN IPv6 Routing Header compression according to RFC6282.
+
+config 6LOWPAN_NHC_UDP
+	tristate "UDP Header Support"
+	default y
+	help
+	  6LoWPAN IPv6 UDP Header compression according to RFC6282.
+
+config 6LOWPAN_GHC_EXT_HDR_HOP
+	tristate "GHC Hop-by-Hop Options Header Support"
+	help
+	  6LoWPAN IPv6 Hop-by-Hop option generic header compression according
+	  to RFC7400.
+
+config 6LOWPAN_GHC_UDP
+	tristate "GHC UDP Support"
+	help
+	  6LoWPAN IPv6 UDP generic header compression according to RFC7400.
+
+config 6LOWPAN_GHC_ICMPV6
+	tristate "GHC ICMPv6 Support"
+	help
+	  6LoWPAN IPv6 ICMPv6 generic header compression according to RFC7400.
+
+config 6LOWPAN_GHC_EXT_HDR_DEST
+	tristate "GHC Destination Options Header Support"
+	help
+	  6LoWPAN IPv6 destination option generic header compression according
+	  to RFC7400.
+
+config 6LOWPAN_GHC_EXT_HDR_FRAG
+	tristate "GHC Fragmentation Options Header Support"
+	help
+	  6LoWPAN IPv6 fragmentation option generic header compression
+	  according to RFC7400.
+
+config 6LOWPAN_GHC_EXT_HDR_ROUTE
+	tristate "GHC Routing Options Header Support"
+	help
+	  6LoWPAN IPv6 routing option generic header compression according
+	  to RFC7400.
+
+endif
diff --git a/net/6lowpan/Makefile b/net/6lowpan/Makefile
new file mode 100644
index 000000000..2247b96db
--- /dev/null
+++ b/net/6lowpan/Makefile
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_6LOWPAN) += 6lowpan.o
+
+6lowpan-y := core.o iphc.o nhc.o ndisc.o
+6lowpan-$(CONFIG_6LOWPAN_DEBUGFS) += debugfs.o
+
+#rfc6282 nhcs
+obj-$(CONFIG_6LOWPAN_NHC_DEST) += nhc_dest.o
+obj-$(CONFIG_6LOWPAN_NHC_FRAGMENT) += nhc_fragment.o
+obj-$(CONFIG_6LOWPAN_NHC_HOP) += nhc_hop.o
+obj-$(CONFIG_6LOWPAN_NHC_IPV6) += nhc_ipv6.o
+obj-$(CONFIG_6LOWPAN_NHC_MOBILITY) += nhc_mobility.o
+obj-$(CONFIG_6LOWPAN_NHC_ROUTING) += nhc_routing.o
+obj-$(CONFIG_6LOWPAN_NHC_UDP) += nhc_udp.o
+
+#rfc7400 ghcs
+obj-$(CONFIG_6LOWPAN_GHC_EXT_HDR_HOP) += nhc_ghc_ext_hop.o
+obj-$(CONFIG_6LOWPAN_GHC_UDP) += nhc_ghc_udp.o
+obj-$(CONFIG_6LOWPAN_GHC_ICMPV6) += nhc_ghc_icmpv6.o
+obj-$(CONFIG_6LOWPAN_GHC_EXT_HDR_DEST) += nhc_ghc_ext_dest.o
+obj-$(CONFIG_6LOWPAN_GHC_EXT_HDR_FRAG) += nhc_ghc_ext_frag.o
+obj-$(CONFIG_6LOWPAN_GHC_EXT_HDR_ROUTE) += nhc_ghc_ext_route.o
diff --git a/net/6lowpan/core.c b/net/6lowpan/core.c
new file mode 100644
index 000000000..a068757ea
--- /dev/null
+++ b/net/6lowpan/core.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Authors:
+ * (C) 2015 Pengutronix, Alexander Aring <aar@pengutronix.de>
+ */
+
+#include <linux/module.h>
+
+#include <net/6lowpan.h>
+#include <net/addrconf.h>
+
+#include "6lowpan_i.h"
+
+int lowpan_register_netdevice(struct net_device *dev,
+			      enum lowpan_lltypes lltype)
+{
+	int i, ret;
+
+	switch (lltype) {
+	case LOWPAN_LLTYPE_IEEE802154:
+		dev->addr_len = EUI64_ADDR_LEN;
+		break;
+
+	case LOWPAN_LLTYPE_BTLE:
+		dev->addr_len = ETH_ALEN;
+		break;
+	}
+
+	dev->type = ARPHRD_6LOWPAN;
+	dev->mtu = IPV6_MIN_MTU;
+
+	lowpan_dev(dev)->lltype = lltype;
+
+	spin_lock_init(&lowpan_dev(dev)->ctx.lock);
+	for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++)
+		lowpan_dev(dev)->ctx.table[i].id = i;
+
+	dev->ndisc_ops = &lowpan_ndisc_ops;
+
+	ret = register_netdevice(dev);
+	if (ret < 0)
+		return ret;
+
+	lowpan_dev_debugfs_init(dev);
+
+	return ret;
+}
+EXPORT_SYMBOL(lowpan_register_netdevice);
+
+int lowpan_register_netdev(struct net_device *dev,
+			   enum lowpan_lltypes lltype)
+{
+	int ret;
+
+	rtnl_lock();
+	ret = lowpan_register_netdevice(dev, lltype);
+	rtnl_unlock();
+	return ret;
+}
+EXPORT_SYMBOL(lowpan_register_netdev);
+
+void lowpan_unregister_netdevice(struct net_device *dev)
+{
+	unregister_netdevice(dev);
+	lowpan_dev_debugfs_exit(dev);
+}
+EXPORT_SYMBOL(lowpan_unregister_netdevice);
+
+void lowpan_unregister_netdev(struct net_device *dev)
+{
+	rtnl_lock();
+	lowpan_unregister_netdevice(dev);
+	rtnl_unlock();
+}
+EXPORT_SYMBOL(lowpan_unregister_netdev);
+
+int addrconf_ifid_802154_6lowpan(u8 *eui, struct net_device *dev)
+{
+	struct wpan_dev *wpan_dev = lowpan_802154_dev(dev)->wdev->ieee802154_ptr;
+
+	/* Set short_addr autoconfiguration if short_addr is present only */
+	if (!lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr))
+		return -1;
+
+	/* For either address format, all zero addresses MUST NOT be used */
+	if (wpan_dev->pan_id == cpu_to_le16(0x0000) &&
+	    wpan_dev->short_addr == cpu_to_le16(0x0000))
+		return -1;
+
+	/* Alternatively, if no PAN ID is known, 16 zero bits may be used */
+	if (wpan_dev->pan_id == cpu_to_le16(IEEE802154_PAN_ID_BROADCAST))
+		memset(eui, 0, 2);
+	else
+		ieee802154_le16_to_be16(eui, &wpan_dev->pan_id);
+
+	/* The "Universal/Local" (U/L) bit shall be set to zero */
+	eui[0] &= ~2;
+	eui[2] = 0;
+	eui[3] = 0xFF;
+	eui[4] = 0xFE;
+	eui[5] = 0;
+	ieee802154_le16_to_be16(&eui[6], &wpan_dev->short_addr);
+	return 0;
+}
+
+static int lowpan_event(struct notifier_block *unused,
+			unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct inet6_dev *idev;
+	struct in6_addr addr;
+	int i;
+
+	if (dev->type != ARPHRD_6LOWPAN)
+		return NOTIFY_DONE;
+
+	idev = __in6_dev_get(dev);
+	if (!idev)
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UP:
+	case NETDEV_CHANGE:
+		/* (802.15.4 6LoWPAN short address slaac handling */
+		if (lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154) &&
+		    addrconf_ifid_802154_6lowpan(addr.s6_addr + 8, dev) == 0) {
+			__ipv6_addr_set_half(&addr.s6_addr32[0],
+					     htonl(0xFE800000), 0);
+			addrconf_add_linklocal(idev, &addr, 0);
+		}
+		break;
+	case NETDEV_DOWN:
+		for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++)
+			clear_bit(LOWPAN_IPHC_CTX_FLAG_ACTIVE,
+				  &lowpan_dev(dev)->ctx.table[i].flags);
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block lowpan_notifier = {
+	.notifier_call = lowpan_event,
+};
+
+static int __init lowpan_module_init(void)
+{
+	int ret;
+
+	lowpan_debugfs_init();
+
+	ret = register_netdevice_notifier(&lowpan_notifier);
+	if (ret < 0) {
+		lowpan_debugfs_exit();
+		return ret;
+	}
+
+	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;
+}
+
+static void __exit lowpan_module_exit(void)
+{
+	lowpan_debugfs_exit();
+	unregister_netdevice_notifier(&lowpan_notifier);
+}
+
+module_init(lowpan_module_init);
+module_exit(lowpan_module_exit);
+
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/debugfs.c b/net/6lowpan/debugfs.c
new file mode 100644
index 000000000..600b9563b
--- /dev/null
+++ b/net/6lowpan/debugfs.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Authors:
+ * (C) 2015 Pengutronix, Alexander Aring <aar@pengutronix.de>
+ * Copyright (c)  2015 Nordic Semiconductor. All Rights Reserved.
+ */
+
+#include <net/6lowpan.h>
+
+#include "6lowpan_i.h"
+
+#define LOWPAN_DEBUGFS_CTX_PFX_NUM_ARGS	8
+
+static struct dentry *lowpan_debugfs;
+
+static int lowpan_ctx_flag_active_set(void *data, u64 val)
+{
+	struct lowpan_iphc_ctx *ctx = data;
+
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	if (val)
+		set_bit(LOWPAN_IPHC_CTX_FLAG_ACTIVE, &ctx->flags);
+	else
+		clear_bit(LOWPAN_IPHC_CTX_FLAG_ACTIVE, &ctx->flags);
+
+	return 0;
+}
+
+static int lowpan_ctx_flag_active_get(void *data, u64 *val)
+{
+	*val = lowpan_iphc_ctx_is_active(data);
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(lowpan_ctx_flag_active_fops,
+			 lowpan_ctx_flag_active_get,
+			 lowpan_ctx_flag_active_set, "%llu\n");
+
+static int lowpan_ctx_flag_c_set(void *data, u64 val)
+{
+	struct lowpan_iphc_ctx *ctx = data;
+
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	if (val)
+		set_bit(LOWPAN_IPHC_CTX_FLAG_COMPRESSION, &ctx->flags);
+	else
+		clear_bit(LOWPAN_IPHC_CTX_FLAG_COMPRESSION, &ctx->flags);
+
+	return 0;
+}
+
+static int lowpan_ctx_flag_c_get(void *data, u64 *val)
+{
+	*val = lowpan_iphc_ctx_is_compression(data);
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(lowpan_ctx_flag_c_fops, lowpan_ctx_flag_c_get,
+			 lowpan_ctx_flag_c_set, "%llu\n");
+
+static int lowpan_ctx_plen_set(void *data, u64 val)
+{
+	struct lowpan_iphc_ctx *ctx = data;
+	struct lowpan_iphc_ctx_table *t =
+		container_of(ctx, struct lowpan_iphc_ctx_table, table[ctx->id]);
+
+	if (val > 128)
+		return -EINVAL;
+
+	spin_lock_bh(&t->lock);
+	ctx->plen = val;
+	spin_unlock_bh(&t->lock);
+
+	return 0;
+}
+
+static int lowpan_ctx_plen_get(void *data, u64 *val)
+{
+	struct lowpan_iphc_ctx *ctx = data;
+	struct lowpan_iphc_ctx_table *t =
+		container_of(ctx, struct lowpan_iphc_ctx_table, table[ctx->id]);
+
+	spin_lock_bh(&t->lock);
+	*val = ctx->plen;
+	spin_unlock_bh(&t->lock);
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(lowpan_ctx_plen_fops, lowpan_ctx_plen_get,
+			 lowpan_ctx_plen_set, "%llu\n");
+
+static int lowpan_ctx_pfx_show(struct seq_file *file, void *offset)
+{
+	struct lowpan_iphc_ctx *ctx = file->private;
+	struct lowpan_iphc_ctx_table *t =
+		container_of(ctx, struct lowpan_iphc_ctx_table, table[ctx->id]);
+
+	spin_lock_bh(&t->lock);
+	seq_printf(file, "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
+		   be16_to_cpu(ctx->pfx.s6_addr16[0]),
+		   be16_to_cpu(ctx->pfx.s6_addr16[1]),
+		   be16_to_cpu(ctx->pfx.s6_addr16[2]),
+		   be16_to_cpu(ctx->pfx.s6_addr16[3]),
+		   be16_to_cpu(ctx->pfx.s6_addr16[4]),
+		   be16_to_cpu(ctx->pfx.s6_addr16[5]),
+		   be16_to_cpu(ctx->pfx.s6_addr16[6]),
+		   be16_to_cpu(ctx->pfx.s6_addr16[7]));
+	spin_unlock_bh(&t->lock);
+
+	return 0;
+}
+
+static int lowpan_ctx_pfx_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, lowpan_ctx_pfx_show, inode->i_private);
+}
+
+static ssize_t lowpan_ctx_pfx_write(struct file *fp,
+				    const char __user *user_buf, size_t count,
+				    loff_t *ppos)
+{
+	char buf[128] = {};
+	struct seq_file *file = fp->private_data;
+	struct lowpan_iphc_ctx *ctx = file->private;
+	struct lowpan_iphc_ctx_table *t =
+		container_of(ctx, struct lowpan_iphc_ctx_table, table[ctx->id]);
+	int status = count, n, i;
+	unsigned int addr[8];
+
+	if (copy_from_user(&buf, user_buf, min_t(size_t, sizeof(buf) - 1,
+						 count))) {
+		status = -EFAULT;
+		goto out;
+	}
+
+	n = sscanf(buf, "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x",
+		   &addr[0], &addr[1], &addr[2], &addr[3], &addr[4],
+		   &addr[5], &addr[6], &addr[7]);
+	if (n != LOWPAN_DEBUGFS_CTX_PFX_NUM_ARGS) {
+		status = -EINVAL;
+		goto out;
+	}
+
+	spin_lock_bh(&t->lock);
+	for (i = 0; i < 8; i++)
+		ctx->pfx.s6_addr16[i] = cpu_to_be16(addr[i] & 0xffff);
+	spin_unlock_bh(&t->lock);
+
+out:
+	return status;
+}
+
+static const struct file_operations lowpan_ctx_pfx_fops = {
+	.open		= lowpan_ctx_pfx_open,
+	.read		= seq_read,
+	.write		= lowpan_ctx_pfx_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static void lowpan_dev_debugfs_ctx_init(struct net_device *dev,
+					struct dentry *ctx, u8 id)
+{
+	struct lowpan_dev *ldev = lowpan_dev(dev);
+	struct dentry *root;
+	char buf[32];
+
+	if (WARN_ON_ONCE(id >= LOWPAN_IPHC_CTX_TABLE_SIZE))
+		return;
+
+	sprintf(buf, "%d", id);
+
+	root = debugfs_create_dir(buf, ctx);
+
+	debugfs_create_file("active", 0644, root, &ldev->ctx.table[id],
+			    &lowpan_ctx_flag_active_fops);
+
+	debugfs_create_file("compression", 0644, root, &ldev->ctx.table[id],
+			    &lowpan_ctx_flag_c_fops);
+
+	debugfs_create_file("prefix", 0644, root, &ldev->ctx.table[id],
+			    &lowpan_ctx_pfx_fops);
+
+	debugfs_create_file("prefix_len", 0644, root, &ldev->ctx.table[id],
+			    &lowpan_ctx_plen_fops);
+}
+
+static int lowpan_context_show(struct seq_file *file, void *offset)
+{
+	struct lowpan_iphc_ctx_table *t = file->private;
+	int i;
+
+	seq_printf(file, "%3s|%-43s|%c\n", "cid", "prefix", 'C');
+	seq_puts(file, "-------------------------------------------------\n");
+
+	spin_lock_bh(&t->lock);
+	for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++) {
+		if (!lowpan_iphc_ctx_is_active(&t->table[i]))
+			continue;
+
+		seq_printf(file, "%3d|%39pI6c/%-3d|%d\n", t->table[i].id,
+			   &t->table[i].pfx, t->table[i].plen,
+			   lowpan_iphc_ctx_is_compression(&t->table[i]));
+	}
+	spin_unlock_bh(&t->lock);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(lowpan_context);
+
+static int lowpan_short_addr_get(void *data, u64 *val)
+{
+	struct wpan_dev *wdev = data;
+
+	rtnl_lock();
+	*val = le16_to_cpu(wdev->short_addr);
+	rtnl_unlock();
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(lowpan_short_addr_fops, lowpan_short_addr_get, NULL,
+			 "0x%04llx\n");
+
+static void lowpan_dev_debugfs_802154_init(const struct net_device *dev,
+					  struct lowpan_dev *ldev)
+{
+	struct dentry *root;
+
+	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
+		return;
+
+	root = debugfs_create_dir("ieee802154", ldev->iface_debugfs);
+
+	debugfs_create_file("short_addr", 0444, root,
+			    lowpan_802154_dev(dev)->wdev->ieee802154_ptr,
+			    &lowpan_short_addr_fops);
+}
+
+void lowpan_dev_debugfs_init(struct net_device *dev)
+{
+	struct lowpan_dev *ldev = lowpan_dev(dev);
+	struct dentry *contexts;
+	int i;
+
+	/* creating the root */
+	ldev->iface_debugfs = debugfs_create_dir(dev->name, lowpan_debugfs);
+
+	contexts = debugfs_create_dir("contexts", ldev->iface_debugfs);
+
+	debugfs_create_file("show", 0644, contexts, &lowpan_dev(dev)->ctx,
+			    &lowpan_context_fops);
+
+	for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++)
+		lowpan_dev_debugfs_ctx_init(dev, contexts, i);
+
+	lowpan_dev_debugfs_802154_init(dev, ldev);
+}
+
+void lowpan_dev_debugfs_exit(struct net_device *dev)
+{
+	debugfs_remove_recursive(lowpan_dev(dev)->iface_debugfs);
+}
+
+void __init lowpan_debugfs_init(void)
+{
+	lowpan_debugfs = debugfs_create_dir("6lowpan", NULL);
+}
+
+void lowpan_debugfs_exit(void)
+{
+	debugfs_remove_recursive(lowpan_debugfs);
+}
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
new file mode 100644
index 000000000..52fad5dad
--- /dev/null
+++ b/net/6lowpan/iphc.c
@@ -0,0 +1,1313 @@
+/*
+ * 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 "6lowpan_i.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))
+
+#define lowpan_is_linklocal_zero_padded(a)	\
+	(!(hdr->saddr.s6_addr[1] & 0x3f) &&	\
+	 !hdr->saddr.s6_addr16[1] &&		\
+	 !hdr->saddr.s6_addr32[1])
+
+#define LOWPAN_IPHC_CID_DCI(cid)	(cid & 0x0f)
+#define LOWPAN_IPHC_CID_SCI(cid)	((cid & 0xf0) >> 4)
+
+static inline void
+lowpan_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);
+		lowpan_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;
+	}
+}
+
+static struct lowpan_iphc_ctx *
+lowpan_iphc_ctx_get_by_id(const struct net_device *dev, u8 id)
+{
+	struct lowpan_iphc_ctx *ret = &lowpan_dev(dev)->ctx.table[id];
+
+	if (!lowpan_iphc_ctx_is_active(ret))
+		return NULL;
+
+	return ret;
+}
+
+static struct lowpan_iphc_ctx *
+lowpan_iphc_ctx_get_by_addr(const struct net_device *dev,
+			    const struct in6_addr *addr)
+{
+	struct lowpan_iphc_ctx *table = lowpan_dev(dev)->ctx.table;
+	struct lowpan_iphc_ctx *ret = NULL;
+	struct in6_addr addr_pfx;
+	u8 addr_plen;
+	int i;
+
+	for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++) {
+		/* Check if context is valid. A context that is not valid
+		 * MUST NOT be used for compression.
+		 */
+		if (!lowpan_iphc_ctx_is_active(&table[i]) ||
+		    !lowpan_iphc_ctx_is_compression(&table[i]))
+			continue;
+
+		ipv6_addr_prefix(&addr_pfx, addr, table[i].plen);
+
+		/* if prefix len < 64, the remaining bits until 64th bit is
+		 * zero. Otherwise we use table[i]->plen.
+		 */
+		if (table[i].plen < 64)
+			addr_plen = 64;
+		else
+			addr_plen = table[i].plen;
+
+		if (ipv6_prefix_equal(&addr_pfx, &table[i].pfx, addr_plen)) {
+			/* remember first match */
+			if (!ret) {
+				ret = &table[i];
+				continue;
+			}
+
+			/* get the context with longest prefix len */
+			if (table[i].plen > ret->plen)
+				ret = &table[i];
+		}
+	}
+
+	return ret;
+}
+
+static struct lowpan_iphc_ctx *
+lowpan_iphc_ctx_get_by_mcast_addr(const struct net_device *dev,
+				  const struct in6_addr *addr)
+{
+	struct lowpan_iphc_ctx *table = lowpan_dev(dev)->ctx.table;
+	struct lowpan_iphc_ctx *ret = NULL;
+	struct in6_addr addr_mcast, network_pfx = {};
+	int i;
+
+	/* init mcast address with  */
+	memcpy(&addr_mcast, addr, sizeof(*addr));
+
+	for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++) {
+		/* Check if context is valid. A context that is not valid
+		 * MUST NOT be used for compression.
+		 */
+		if (!lowpan_iphc_ctx_is_active(&table[i]) ||
+		    !lowpan_iphc_ctx_is_compression(&table[i]))
+			continue;
+
+		/* setting plen */
+		addr_mcast.s6_addr[3] = table[i].plen;
+		/* get network prefix to copy into multicast address */
+		ipv6_addr_prefix(&network_pfx, &table[i].pfx,
+				 table[i].plen);
+		/* setting network prefix */
+		memcpy(&addr_mcast.s6_addr[4], &network_pfx, 8);
+
+		if (ipv6_addr_equal(addr, &addr_mcast)) {
+			ret = &table[i];
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static void lowpan_iphc_uncompress_lladdr(const struct net_device *dev,
+					  struct in6_addr *ipaddr,
+					  const void *lladdr)
+{
+	switch (dev->addr_len) {
+	case ETH_ALEN:
+		lowpan_iphc_uncompress_eui48_lladdr(ipaddr, lladdr);
+		break;
+	case EUI64_ADDR_LEN:
+		lowpan_iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+}
+
+/* Uncompress address function for source and
+ * destination address(non-multicast).
+ *
+ * address_mode is the masked value for sam or dam value
+ */
+static int lowpan_iphc_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) {
+	/* 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_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_SAM_10:
+	case LOWPAN_IPHC_DAM_10:
+		/* 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_SAM_11:
+	case LOWPAN_IPHC_DAM_11:
+		fail = false;
+		switch (lowpan_dev(dev)->lltype) {
+		case LOWPAN_LLTYPE_IEEE802154:
+			lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
+			break;
+		default:
+			lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
+			break;
+		}
+		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 lowpan_iphc_uncompress_ctx_addr(struct sk_buff *skb,
+					   const struct net_device *dev,
+					   const struct lowpan_iphc_ctx *ctx,
+					   struct in6_addr *ipaddr,
+					   u8 address_mode, const void *lladdr)
+{
+	bool fail;
+
+	switch (address_mode) {
+	/* SAM and DAM are the same here */
+	case LOWPAN_IPHC_DAM_00:
+		fail = false;
+		/* SAM_00 -> unspec address ::
+		 * Do nothing, address is already ::
+		 *
+		 * DAM 00 -> reserved should never occur.
+		 */
+		break;
+	case LOWPAN_IPHC_SAM_01:
+	case LOWPAN_IPHC_DAM_01:
+		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
+		ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
+		break;
+	case LOWPAN_IPHC_SAM_10:
+	case LOWPAN_IPHC_DAM_10:
+		ipaddr->s6_addr[11] = 0xFF;
+		ipaddr->s6_addr[12] = 0xFE;
+		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
+		ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
+		break;
+	case LOWPAN_IPHC_SAM_11:
+	case LOWPAN_IPHC_DAM_11:
+		fail = false;
+		switch (lowpan_dev(dev)->lltype) {
+		case LOWPAN_LLTYPE_IEEE802154:
+			lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
+			break;
+		default:
+			lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
+			break;
+		}
+		ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
+		break;
+	default:
+		pr_debug("Invalid sam 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 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,
+					     u8 address_mode)
+{
+	bool fail;
+
+	switch (address_mode) {
+	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", address_mode);
+		return -EINVAL;
+	}
+
+	if (fail) {
+		pr_debug("Failed to fetch skb data\n");
+		return -EIO;
+	}
+
+	raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
+			ipaddr->s6_addr, 16);
+
+	return 0;
+}
+
+static int lowpan_uncompress_multicast_ctx_daddr(struct sk_buff *skb,
+						 struct lowpan_iphc_ctx *ctx,
+						 struct in6_addr *ipaddr,
+						 u8 address_mode)
+{
+	struct in6_addr network_pfx = {};
+	bool fail;
+
+	ipaddr->s6_addr[0] = 0xFF;
+	fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 2);
+	fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[12], 4);
+	if (fail)
+		return -EIO;
+
+	/* take prefix_len and network prefix from the context */
+	ipaddr->s6_addr[3] = ctx->plen;
+	/* get network prefix to copy into multicast address */
+	ipv6_addr_prefix(&network_pfx, &ctx->pfx, ctx->plen);
+	/* setting network prefix */
+	memcpy(&ipaddr->s6_addr[4], &network_pfx, 8);
+
+	return 0;
+}
+
+/* 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)
+{
+	/* get the two higher bits which is ecn */
+	u8 ecn = tf[0] & 0xc0;
+
+	/* ECN takes 0x30 in hdr->flow_lbl[0] */
+	hdr->flow_lbl[0] |= (ecn >> 2);
+}
+
+/* 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;
+
+	/* 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);
+}
+
+/* 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.
+	 */
+	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;
+
+		/*                      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;
+	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;
+
+		/*                     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;
+	case LOWPAN_IPHC_TF_10:
+		/* ECN + DSCP (1 byte), Flow Label is elided. */
+		if (lowpan_fetch_skb(skb, tf, 1))
+			return -EINVAL;
+
+		/*  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;
+	case LOWPAN_IPHC_TF_11:
+		/* Traffic Class and Flow Label are elided */
+		break;
+	default:
+		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 = {};
+	struct lowpan_iphc_ctx *ci;
+	u8 iphc0, iphc1, cid = 0;
+	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;
+
+	hdr.version = 6;
+
+	/* default CID = 0, another if the CID flag is set */
+	if (iphc1 & LOWPAN_IPHC_CID) {
+		if (lowpan_fetch_skb(skb, &cid, sizeof(cid)))
+			return -EINVAL;
+	}
+
+	err = lowpan_iphc_tf_decompress(skb, &hdr,
+					iphc0 & LOWPAN_IPHC_TF_MASK);
+	if (err < 0)
+		return err;
+
+	/* Next Header */
+	if (!(iphc0 & LOWPAN_IPHC_NH)) {
+		/* 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 & 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;
+	}
+
+	if (iphc1 & LOWPAN_IPHC_SAC) {
+		spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
+		ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_SCI(cid));
+		if (!ci) {
+			spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
+			return -EINVAL;
+		}
+
+		pr_debug("SAC bit is set. Handle context based source address.\n");
+		err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.saddr,
+						      iphc1 & LOWPAN_IPHC_SAM_MASK,
+						      saddr);
+		spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
+	} else {
+		/* Source address uncompression */
+		pr_debug("source address stateless compression\n");
+		err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.saddr,
+						  iphc1 & LOWPAN_IPHC_SAM_MASK,
+						  saddr);
+	}
+
+	/* Check on error of previous branch */
+	if (err)
+		return -EINVAL;
+
+	switch (iphc1 & (LOWPAN_IPHC_M | LOWPAN_IPHC_DAC)) {
+	case LOWPAN_IPHC_M | LOWPAN_IPHC_DAC:
+		skb->pkt_type = PACKET_BROADCAST;
+
+		spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
+		ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
+		if (!ci) {
+			spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
+			return -EINVAL;
+		}
+
+		/* multicast with context */
+		pr_debug("dest: context-based mcast compression\n");
+		err = lowpan_uncompress_multicast_ctx_daddr(skb, ci,
+							    &hdr.daddr,
+							    iphc1 & LOWPAN_IPHC_DAM_MASK);
+		spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
+		break;
+	case LOWPAN_IPHC_M:
+		skb->pkt_type = PACKET_BROADCAST;
+
+		/* multicast */
+		err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
+							iphc1 & LOWPAN_IPHC_DAM_MASK);
+		break;
+	case LOWPAN_IPHC_DAC:
+		skb->pkt_type = PACKET_HOST;
+
+		spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
+		ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
+		if (!ci) {
+			spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
+			return -EINVAL;
+		}
+
+		/* Destination address context based uncompression */
+		pr_debug("DAC bit is set. Handle context based destination address.\n");
+		err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.daddr,
+						      iphc1 & LOWPAN_IPHC_DAM_MASK,
+						      daddr);
+		spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
+		break;
+	default:
+		skb->pkt_type = PACKET_HOST;
+
+		err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.daddr,
+						  iphc1 & LOWPAN_IPHC_DAM_MASK,
+						  daddr);
+		pr_debug("dest: stateless compression mode %d dest %pI6c\n",
+			 iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
+		break;
+	}
+
+	if (err)
+		return -EINVAL;
+
+	/* Next header data uncompression */
+	if (iphc0 & LOWPAN_IPHC_NH) {
+		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;
+	}
+
+	switch (lowpan_dev(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);
+
+	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_mac_header(skb);
+	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 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 inline bool
+lowpan_iphc_compress_ctx_802154_lladdr(const struct in6_addr *ipaddr,
+				       const struct lowpan_iphc_ctx *ctx,
+				       const void *lladdr)
+{
+	const struct ieee802154_addr *addr = lladdr;
+	unsigned char extended_addr[EUI64_ADDR_LEN];
+	bool lladdr_compress = false;
+	struct in6_addr tmp = {};
+
+	switch (addr->mode) {
+	case IEEE802154_ADDR_LONG:
+		ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
+		/* check for SAM/DAM = 11 */
+		memcpy(&tmp.s6_addr[8], &extended_addr, EUI64_ADDR_LEN);
+		/* second bit-flip (Universe/Local) is done according RFC2464 */
+		tmp.s6_addr[8] ^= 0x02;
+		/* context information are always used */
+		ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
+		if (ipv6_addr_equal(&tmp, ipaddr))
+			lladdr_compress = true;
+		break;
+	case IEEE802154_ADDR_SHORT:
+		tmp.s6_addr[11] = 0xFF;
+		tmp.s6_addr[12] = 0xFE;
+		ieee802154_le16_to_be16(&tmp.s6_addr16[7],
+					&addr->short_addr);
+		/* context information are always used */
+		ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
+		if (ipv6_addr_equal(&tmp, ipaddr))
+			lladdr_compress = true;
+		break;
+	default:
+		/* should never handled and filtered by 802154 6lowpan */
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	return lladdr_compress;
+}
+
+static bool lowpan_iphc_addr_equal(const struct net_device *dev,
+				   const struct lowpan_iphc_ctx *ctx,
+				   const struct in6_addr *ipaddr,
+				   const void *lladdr)
+{
+	struct in6_addr tmp = {};
+
+	lowpan_iphc_uncompress_lladdr(dev, &tmp, lladdr);
+
+	if (ctx)
+		ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
+
+	return ipv6_addr_equal(&tmp, ipaddr);
+}
+
+static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
+				   const struct in6_addr *ipaddr,
+				   const struct lowpan_iphc_ctx *ctx,
+				   const unsigned char *lladdr, bool sam)
+{
+	struct in6_addr tmp = {};
+	u8 dam;
+
+	switch (lowpan_dev(dev)->lltype) {
+	case LOWPAN_LLTYPE_IEEE802154:
+		if (lowpan_iphc_compress_ctx_802154_lladdr(ipaddr, ctx,
+							   lladdr)) {
+			dam = LOWPAN_IPHC_DAM_11;
+			goto out;
+		}
+		break;
+	default:
+		if (lowpan_iphc_addr_equal(dev, ctx, ipaddr, lladdr)) {
+			dam = LOWPAN_IPHC_DAM_11;
+			goto out;
+		}
+		break;
+	}
+
+	memset(&tmp, 0, sizeof(tmp));
+	/* check for SAM/DAM = 10 */
+	tmp.s6_addr[11] = 0xFF;
+	tmp.s6_addr[12] = 0xFE;
+	memcpy(&tmp.s6_addr[14], &ipaddr->s6_addr[14], 2);
+	/* context information are always used */
+	ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
+	if (ipv6_addr_equal(&tmp, ipaddr)) {
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[14], 2);
+		dam = LOWPAN_IPHC_DAM_10;
+		goto out;
+	}
+
+	memset(&tmp, 0, sizeof(tmp));
+	/* check for SAM/DAM = 01, should always match */
+	memcpy(&tmp.s6_addr[8], &ipaddr->s6_addr[8], 8);
+	/* context information are always used */
+	ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
+	if (ipv6_addr_equal(&tmp, ipaddr)) {
+		lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[8], 8);
+		dam = LOWPAN_IPHC_DAM_01;
+		goto out;
+	}
+
+	WARN_ONCE(1, "context found but no address mode matched\n");
+	return LOWPAN_IPHC_DAM_00;
+out:
+
+	if (sam)
+		return lowpan_iphc_dam_to_sam_value[dam];
+	else
+		return dam;
+}
+
+static inline bool
+lowpan_iphc_compress_802154_lladdr(const struct in6_addr *ipaddr,
+				   const void *lladdr)
+{
+	const struct ieee802154_addr *addr = lladdr;
+	unsigned char extended_addr[EUI64_ADDR_LEN];
+	bool lladdr_compress = false;
+	struct in6_addr tmp = {};
+
+	switch (addr->mode) {
+	case IEEE802154_ADDR_LONG:
+		ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
+		if (is_addr_mac_addr_based(ipaddr, extended_addr))
+			lladdr_compress = true;
+		break;
+	case IEEE802154_ADDR_SHORT:
+		/* fe:80::ff:fe00:XXXX
+		 *                \__/
+		 *             short_addr
+		 *
+		 * Universe/Local bit is zero.
+		 */
+		tmp.s6_addr[0] = 0xFE;
+		tmp.s6_addr[1] = 0x80;
+		tmp.s6_addr[11] = 0xFF;
+		tmp.s6_addr[12] = 0xFE;
+		ieee802154_le16_to_be16(&tmp.s6_addr16[7],
+					&addr->short_addr);
+		if (ipv6_addr_equal(&tmp, ipaddr))
+			lladdr_compress = true;
+		break;
+	default:
+		/* should never handled and filtered by 802154 6lowpan */
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	return lladdr_compress;
+}
+
+static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct net_device *dev,
+				  const struct in6_addr *ipaddr,
+				  const unsigned char *lladdr, bool sam)
+{
+	u8 dam = LOWPAN_IPHC_DAM_01;
+
+	switch (lowpan_dev(dev)->lltype) {
+	case LOWPAN_LLTYPE_IEEE802154:
+		if (lowpan_iphc_compress_802154_lladdr(ipaddr, lladdr)) {
+			dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
+			pr_debug("address compression 0 bits\n");
+			goto out;
+		}
+		break;
+	default:
+		if (lowpan_iphc_addr_equal(dev, NULL, ipaddr, lladdr)) {
+			dam = LOWPAN_IPHC_DAM_11;
+			pr_debug("address compression 0 bits\n");
+			goto out;
+		}
+
+		break;
+	}
+
+	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);
+		dam = LOWPAN_IPHC_DAM_10; /* 16-bits */
+		raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
+				*hc_ptr - 2, 2);
+		goto out;
+	}
+
+	/* do not compress IID => xxxx::IID */
+	lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
+	raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
+			*hc_ptr - 8, 8);
+
+out:
+
+	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;
+}
+
+static u8 lowpan_iphc_mcast_ctx_addr_compress(u8 **hc_ptr,
+					      const struct lowpan_iphc_ctx *ctx,
+					      const struct in6_addr *ipaddr)
+{
+	u8 data[6];
+
+	/* flags/scope, reserved (RIID) */
+	memcpy(data, &ipaddr->s6_addr[1], 2);
+	/* group ID */
+	memcpy(&data[1], &ipaddr->s6_addr[11], 4);
+	lowpan_push_hc_data(hc_ptr, data, 6);
+
+	return LOWPAN_IPHC_DAM_00;
+}
+
+static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
+					  const struct in6_addr *ipaddr)
+{
+	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, cid = 0;
+	struct ipv6hdr *hdr;
+	u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
+	struct lowpan_iphc_ctx *dci, *sci, dci_entry, sci_entry;
+	int ret, ipv6_daddr_type, ipv6_saddr_type;
+
+	if (skb->protocol != htons(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;
+
+	raw_dump_table(__func__, "sending raw skb network uncompressed packet",
+		       skb->data, skb->len);
+
+	ipv6_daddr_type = ipv6_addr_type(&hdr->daddr);
+	spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
+	if (ipv6_daddr_type & IPV6_ADDR_MULTICAST)
+		dci = lowpan_iphc_ctx_get_by_mcast_addr(dev, &hdr->daddr);
+	else
+		dci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->daddr);
+	if (dci) {
+		memcpy(&dci_entry, dci, sizeof(*dci));
+		cid |= dci->id;
+	}
+	spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
+
+	spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
+	sci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->saddr);
+	if (sci) {
+		memcpy(&sci_entry, sci, sizeof(*sci));
+		cid |= (sci->id << 4);
+	}
+	spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
+
+	/* if cid is zero it will be compressed */
+	if (cid) {
+		iphc1 |= LOWPAN_IPHC_CID;
+		lowpan_push_hc_data(&hc_ptr, &cid, sizeof(cid));
+	}
+
+	/* 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);
+	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
+	 * 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_HLIM_01;
+		break;
+	case 64:
+		iphc0 |= LOWPAN_IPHC_HLIM_10;
+		break;
+	case 255:
+		iphc0 |= LOWPAN_IPHC_HLIM_11;
+		break;
+	default:
+		lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
+				    sizeof(hdr->hop_limit));
+	}
+
+	ipv6_saddr_type = ipv6_addr_type(&hdr->saddr);
+	/* source address compression */
+	if (ipv6_saddr_type == IPV6_ADDR_ANY) {
+		pr_debug("source address is unspecified, setting SAC\n");
+		iphc1 |= LOWPAN_IPHC_SAC;
+	} else {
+		if (sci) {
+			iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
+							  &hdr->saddr,
+							  &sci_entry, saddr,
+							  true);
+			iphc1 |= LOWPAN_IPHC_SAC;
+		} else {
+			if (ipv6_saddr_type & IPV6_ADDR_LINKLOCAL &&
+			    lowpan_is_linklocal_zero_padded(hdr->saddr)) {
+				iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
+								 &hdr->saddr,
+								 saddr, true);
+				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);
+			}
+		}
+	}
+
+	/* destination address compression */
+	if (ipv6_daddr_type & IPV6_ADDR_MULTICAST) {
+		pr_debug("destination address is multicast: ");
+		iphc1 |= LOWPAN_IPHC_M;
+		if (dci) {
+			iphc1 |= lowpan_iphc_mcast_ctx_addr_compress(&hc_ptr,
+								     &dci_entry,
+								     &hdr->daddr);
+			iphc1 |= LOWPAN_IPHC_DAC;
+		} else {
+			iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr,
+								 &hdr->daddr);
+		}
+	} else {
+		if (dci) {
+			iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
+							  &hdr->daddr,
+							  &dci_entry, daddr,
+							  false);
+			iphc1 |= LOWPAN_IPHC_DAC;
+		} else {
+			if (ipv6_daddr_type & IPV6_ADDR_LINKLOCAL &&
+			    lowpan_is_linklocal_zero_padded(hdr->daddr)) {
+				iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
+								 &hdr->daddr,
+								 daddr, false);
+				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) {
+		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);
diff --git a/net/6lowpan/ndisc.c b/net/6lowpan/ndisc.c
new file mode 100644
index 000000000..16be8f8b2
--- /dev/null
+++ b/net/6lowpan/ndisc.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Authors:
+ * (C) 2016 Pengutronix, Alexander Aring <aar@pengutronix.de>
+ */
+
+#include <net/6lowpan.h>
+#include <net/addrconf.h>
+#include <net/ndisc.h>
+
+#include "6lowpan_i.h"
+
+static int lowpan_ndisc_is_useropt(u8 nd_opt_type)
+{
+	return nd_opt_type == ND_OPT_6CO;
+}
+
+#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
+#define NDISC_802154_SHORT_ADDR_LENGTH	1
+static int lowpan_ndisc_parse_802154_options(const struct net_device *dev,
+					     struct nd_opt_hdr *nd_opt,
+					     struct ndisc_options *ndopts)
+{
+	switch (nd_opt->nd_opt_len) {
+	case NDISC_802154_SHORT_ADDR_LENGTH:
+		if (ndopts->nd_802154_opt_array[nd_opt->nd_opt_type])
+			ND_PRINTK(2, warn,
+				  "%s: duplicated short addr ND6 option found: type=%d\n",
+				  __func__, nd_opt->nd_opt_type);
+		else
+			ndopts->nd_802154_opt_array[nd_opt->nd_opt_type] = nd_opt;
+		return 1;
+	default:
+		/* all others will be handled by ndisc IPv6 option parsing */
+		return 0;
+	}
+}
+
+static int lowpan_ndisc_parse_options(const struct net_device *dev,
+				      struct nd_opt_hdr *nd_opt,
+				      struct ndisc_options *ndopts)
+{
+	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
+		return 0;
+
+	switch (nd_opt->nd_opt_type) {
+	case ND_OPT_SOURCE_LL_ADDR:
+	case ND_OPT_TARGET_LL_ADDR:
+		return lowpan_ndisc_parse_802154_options(dev, nd_opt, ndopts);
+	default:
+		return 0;
+	}
+}
+
+static void lowpan_ndisc_802154_update(struct neighbour *n, u32 flags,
+				       u8 icmp6_type,
+				       const struct ndisc_options *ndopts)
+{
+	struct lowpan_802154_neigh *neigh = lowpan_802154_neigh(neighbour_priv(n));
+	u8 *lladdr_short = NULL;
+
+	switch (icmp6_type) {
+	case NDISC_ROUTER_SOLICITATION:
+	case NDISC_ROUTER_ADVERTISEMENT:
+	case NDISC_NEIGHBOUR_SOLICITATION:
+		if (ndopts->nd_802154_opts_src_lladdr) {
+			lladdr_short = __ndisc_opt_addr_data(ndopts->nd_802154_opts_src_lladdr,
+							     IEEE802154_SHORT_ADDR_LEN, 0);
+			if (!lladdr_short) {
+				ND_PRINTK(2, warn,
+					  "NA: invalid short link-layer address length\n");
+				return;
+			}
+		}
+		break;
+	case NDISC_REDIRECT:
+	case NDISC_NEIGHBOUR_ADVERTISEMENT:
+		if (ndopts->nd_802154_opts_tgt_lladdr) {
+			lladdr_short = __ndisc_opt_addr_data(ndopts->nd_802154_opts_tgt_lladdr,
+							     IEEE802154_SHORT_ADDR_LEN, 0);
+			if (!lladdr_short) {
+				ND_PRINTK(2, warn,
+					  "NA: invalid short link-layer address length\n");
+				return;
+			}
+		}
+		break;
+	default:
+		break;
+	}
+
+	write_lock_bh(&n->lock);
+	if (lladdr_short) {
+		ieee802154_be16_to_le16(&neigh->short_addr, lladdr_short);
+		if (!lowpan_802154_is_valid_src_short_addr(neigh->short_addr))
+			neigh->short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
+	}
+	write_unlock_bh(&n->lock);
+}
+
+static void lowpan_ndisc_update(const struct net_device *dev,
+				struct neighbour *n, u32 flags, u8 icmp6_type,
+				const struct ndisc_options *ndopts)
+{
+	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
+		return;
+
+	/* react on overrides only. TODO check if this is really right. */
+	if (flags & NEIGH_UPDATE_F_OVERRIDE)
+		lowpan_ndisc_802154_update(n, flags, icmp6_type, ndopts);
+}
+
+static int lowpan_ndisc_opt_addr_space(const struct net_device *dev,
+				       u8 icmp6_type, struct neighbour *neigh,
+				       u8 *ha_buf, u8 **ha)
+{
+	struct lowpan_802154_neigh *n;
+	struct wpan_dev *wpan_dev;
+	int addr_space = 0;
+
+	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
+		return 0;
+
+	switch (icmp6_type) {
+	case NDISC_REDIRECT:
+		n = lowpan_802154_neigh(neighbour_priv(neigh));
+
+		read_lock_bh(&neigh->lock);
+		if (lowpan_802154_is_valid_src_short_addr(n->short_addr)) {
+			memcpy(ha_buf, &n->short_addr,
+			       IEEE802154_SHORT_ADDR_LEN);
+			read_unlock_bh(&neigh->lock);
+			addr_space += __ndisc_opt_addr_space(IEEE802154_SHORT_ADDR_LEN, 0);
+			*ha = ha_buf;
+		} else {
+			read_unlock_bh(&neigh->lock);
+		}
+		break;
+	case NDISC_NEIGHBOUR_ADVERTISEMENT:
+	case NDISC_NEIGHBOUR_SOLICITATION:
+	case NDISC_ROUTER_SOLICITATION:
+		wpan_dev = lowpan_802154_dev(dev)->wdev->ieee802154_ptr;
+
+		if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr))
+			addr_space = __ndisc_opt_addr_space(IEEE802154_SHORT_ADDR_LEN, 0);
+		break;
+	default:
+		break;
+	}
+
+	return addr_space;
+}
+
+static void lowpan_ndisc_fill_addr_option(const struct net_device *dev,
+					  struct sk_buff *skb, u8 icmp6_type,
+					  const u8 *ha)
+{
+	struct wpan_dev *wpan_dev;
+	__be16 short_addr;
+	u8 opt_type;
+
+	if (!lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154))
+		return;
+
+	switch (icmp6_type) {
+	case NDISC_REDIRECT:
+		if (ha) {
+			ieee802154_le16_to_be16(&short_addr, ha);
+			__ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR,
+						 &short_addr,
+						 IEEE802154_SHORT_ADDR_LEN, 0);
+		}
+		return;
+	case NDISC_NEIGHBOUR_ADVERTISEMENT:
+		opt_type = ND_OPT_TARGET_LL_ADDR;
+		break;
+	case NDISC_ROUTER_SOLICITATION:
+	case NDISC_NEIGHBOUR_SOLICITATION:
+		opt_type = ND_OPT_SOURCE_LL_ADDR;
+		break;
+	default:
+		return;
+	}
+
+	wpan_dev = lowpan_802154_dev(dev)->wdev->ieee802154_ptr;
+
+	if (lowpan_802154_is_valid_src_short_addr(wpan_dev->short_addr)) {
+		ieee802154_le16_to_be16(&short_addr,
+					&wpan_dev->short_addr);
+		__ndisc_fill_addr_option(skb, opt_type, &short_addr,
+					 IEEE802154_SHORT_ADDR_LEN, 0);
+	}
+}
+
+static void lowpan_ndisc_prefix_rcv_add_addr(struct net *net,
+					     struct net_device *dev,
+					     const struct prefix_info *pinfo,
+					     struct inet6_dev *in6_dev,
+					     struct in6_addr *addr,
+					     int addr_type, u32 addr_flags,
+					     bool sllao, bool tokenized,
+					     __u32 valid_lft,
+					     u32 prefered_lft,
+					     bool dev_addr_generated)
+{
+	int err;
+
+	/* generates short based address for RA PIO's */
+	if (lowpan_is_ll(dev, LOWPAN_LLTYPE_IEEE802154) && dev_addr_generated &&
+	    !addrconf_ifid_802154_6lowpan(addr->s6_addr + 8, dev)) {
+		err = addrconf_prefix_rcv_add_addr(net, dev, pinfo, in6_dev,
+						   addr, addr_type, addr_flags,
+						   sllao, tokenized, valid_lft,
+						   prefered_lft);
+		if (err)
+			ND_PRINTK(2, warn,
+				  "RA: could not add a short address based address for prefix: %pI6c\n",
+				  &pinfo->prefix);
+	}
+}
+#endif
+
+const struct ndisc_ops lowpan_ndisc_ops = {
+	.is_useropt		= lowpan_ndisc_is_useropt,
+#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
+	.parse_options		= lowpan_ndisc_parse_options,
+	.update			= lowpan_ndisc_update,
+	.opt_addr_space		= lowpan_ndisc_opt_addr_space,
+	.fill_addr_option	= lowpan_ndisc_fill_addr_option,
+	.prefix_rcv_add_addr	= lowpan_ndisc_prefix_rcv_add_addr,
+#endif
+};
diff --git a/net/6lowpan/nhc.c b/net/6lowpan/nhc.c
new file mode 100644
index 000000000..d6bbbd4ab
--- /dev/null
+++ b/net/6lowpan/nhc.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN next header compression
+ *
+ *	Authors:
+ *	Alexander Aring		<aar@pengutronix.de>
+ */
+
+#include <linux/netdevice.h>
+
+#include <net/ipv6.h>
+
+#include "nhc.h"
+
+static struct rb_root rb_root = RB_ROOT;
+static struct lowpan_nhc *lowpan_nexthdr_nhcs[NEXTHDR_MAX + 1];
+static DEFINE_SPINLOCK(lowpan_nhc_lock);
+
+static int lowpan_nhc_insert(struct lowpan_nhc *nhc)
+{
+	struct rb_node **new = &rb_root.rb_node, *parent = NULL;
+
+	/* Figure out where to put new node */
+	while (*new) {
+		struct lowpan_nhc *this = rb_entry(*new, struct lowpan_nhc,
+						   node);
+		int result, len_dif, len;
+
+		len_dif = nhc->idlen - this->idlen;
+
+		if (nhc->idlen < this->idlen)
+			len = nhc->idlen;
+		else
+			len = this->idlen;
+
+		result = memcmp(nhc->id, this->id, len);
+		if (!result)
+			result = len_dif;
+
+		parent = *new;
+		if (result < 0)
+			new = &((*new)->rb_left);
+		else if (result > 0)
+			new = &((*new)->rb_right);
+		else
+			return -EEXIST;
+	}
+
+	/* Add new node and rebalance tree. */
+	rb_link_node(&nhc->node, parent, new);
+	rb_insert_color(&nhc->node, &rb_root);
+
+	return 0;
+}
+
+static void lowpan_nhc_remove(struct lowpan_nhc *nhc)
+{
+	rb_erase(&nhc->node, &rb_root);
+}
+
+static struct lowpan_nhc *lowpan_nhc_by_nhcid(const struct sk_buff *skb)
+{
+	struct rb_node *node = rb_root.rb_node;
+	const u8 *nhcid_skb_ptr = skb->data;
+
+	while (node) {
+		struct lowpan_nhc *nhc = rb_entry(node, struct lowpan_nhc,
+						  node);
+		u8 nhcid_skb_ptr_masked[LOWPAN_NHC_MAX_ID_LEN];
+		int result, i;
+
+		if (nhcid_skb_ptr + nhc->idlen > skb->data + skb->len)
+			return NULL;
+
+		/* copy and mask afterwards the nhid value from skb */
+		memcpy(nhcid_skb_ptr_masked, nhcid_skb_ptr, nhc->idlen);
+		for (i = 0; i < nhc->idlen; i++)
+			nhcid_skb_ptr_masked[i] &= nhc->idmask[i];
+
+		result = memcmp(nhcid_skb_ptr_masked, nhc->id, nhc->idlen);
+		if (result < 0)
+			node = node->rb_left;
+		else if (result > 0)
+			node = node->rb_right;
+		else
+			return nhc;
+	}
+
+	return NULL;
+}
+
+int lowpan_nhc_check_compression(struct sk_buff *skb,
+				 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))
+		ret = -ENOENT;
+
+	spin_unlock_bh(&lowpan_nhc_lock);
+
+	return ret;
+}
+
+int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
+			      u8 **hc_ptr)
+{
+	int ret;
+	struct lowpan_nhc *nhc;
+
+	spin_lock_bh(&lowpan_nhc_lock);
+
+	nhc = lowpan_nexthdr_nhcs[hdr->nexthdr];
+	/* check if the nhc module was removed in unlocked part.
+	 * TODO: this is a workaround we should prevent unloading
+	 * of nhc modules while unlocked part, this will always drop
+	 * the lowpan packet but it's very unlikely.
+	 *
+	 * Solution isn't easy because we need to decide at
+	 * lowpan_nhc_check_compression if we do a compression or not.
+	 * Because the inline data which is added to skb, we can't move this
+	 * handling.
+	 */
+	if (unlikely(!nhc || !nhc->compress)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* In the case of RAW sockets the transport header is not set by
+	 * the ip6 stack so we must set it ourselves
+	 */
+	if (skb->transport_header == skb->network_header)
+		skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+
+	ret = nhc->compress(skb, hc_ptr);
+	if (ret < 0)
+		goto out;
+
+	/* skip the transport header */
+	skb_pull(skb, nhc->nexthdrlen);
+
+out:
+	spin_unlock_bh(&lowpan_nhc_lock);
+
+	return ret;
+}
+
+int lowpan_nhc_do_uncompression(struct sk_buff *skb,
+				const struct net_device *dev,
+				struct ipv6hdr *hdr)
+{
+	struct lowpan_nhc *nhc;
+	int ret;
+
+	spin_lock_bh(&lowpan_nhc_lock);
+
+	nhc = lowpan_nhc_by_nhcid(skb);
+	if (nhc) {
+		if (nhc->uncompress) {
+			ret = nhc->uncompress(skb, sizeof(struct ipv6hdr) +
+					      nhc->nexthdrlen);
+			if (ret < 0) {
+				spin_unlock_bh(&lowpan_nhc_lock);
+				return ret;
+			}
+		} else {
+			spin_unlock_bh(&lowpan_nhc_lock);
+			netdev_warn(dev, "received nhc id for %s which is not implemented.\n",
+				    nhc->name);
+			return -ENOTSUPP;
+		}
+	} else {
+		spin_unlock_bh(&lowpan_nhc_lock);
+		netdev_warn(dev, "received unknown nhc id which was not found.\n");
+		return -ENOENT;
+	}
+
+	hdr->nexthdr = nhc->nexthdr;
+	skb_reset_transport_header(skb);
+	raw_dump_table(__func__, "raw transport header dump",
+		       skb_transport_header(skb), nhc->nexthdrlen);
+
+	spin_unlock_bh(&lowpan_nhc_lock);
+
+	return 0;
+}
+
+int lowpan_nhc_add(struct lowpan_nhc *nhc)
+{
+	int ret;
+
+	if (!nhc->idlen || !nhc->idsetup)
+		return -EINVAL;
+
+	WARN_ONCE(nhc->idlen > LOWPAN_NHC_MAX_ID_LEN,
+		  "LOWPAN_NHC_MAX_ID_LEN should be updated to %zd.\n",
+		  nhc->idlen);
+
+	nhc->idsetup(nhc);
+
+	spin_lock_bh(&lowpan_nhc_lock);
+
+	if (lowpan_nexthdr_nhcs[nhc->nexthdr]) {
+		ret = -EEXIST;
+		goto out;
+	}
+
+	ret = lowpan_nhc_insert(nhc);
+	if (ret < 0)
+		goto out;
+
+	lowpan_nexthdr_nhcs[nhc->nexthdr] = nhc;
+out:
+	spin_unlock_bh(&lowpan_nhc_lock);
+	return ret;
+}
+EXPORT_SYMBOL(lowpan_nhc_add);
+
+void lowpan_nhc_del(struct lowpan_nhc *nhc)
+{
+	spin_lock_bh(&lowpan_nhc_lock);
+
+	lowpan_nhc_remove(nhc);
+	lowpan_nexthdr_nhcs[nhc->nexthdr] = NULL;
+
+	spin_unlock_bh(&lowpan_nhc_lock);
+
+	synchronize_net();
+}
+EXPORT_SYMBOL(lowpan_nhc_del);
diff --git a/net/6lowpan/nhc.h b/net/6lowpan/nhc.h
new file mode 100644
index 000000000..67951c407
--- /dev/null
+++ b/net/6lowpan/nhc.h
@@ -0,0 +1,143 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __6LOWPAN_NHC_H
+#define __6LOWPAN_NHC_H
+
+#include <linux/skbuff.h>
+#include <linux/rbtree.h>
+#include <linux/module.h>
+
+#include <net/6lowpan.h>
+#include <net/ipv6.h>
+
+/**
+ * LOWPAN_NHC - helper macro to generate nh id fields and lowpan_nhc struct
+ *
+ * @__nhc: variable name of the lowpan_nhc struct.
+ * @_name: const char * of common header compression name.
+ * @_nexthdr: ipv6 nexthdr field for the header compression.
+ * @_nexthdrlen: ipv6 nexthdr len for the reserved space.
+ * @_idsetup: callback to setup id and mask values.
+ * @_idlen: len for the next header id and mask, should be always the same.
+ * @_uncompress: callback for uncompression call.
+ * @_compress: callback for compression call.
+ */
+#define LOWPAN_NHC(__nhc, _name, _nexthdr,	\
+		   _hdrlen, _idsetup, _idlen,	\
+		   _uncompress, _compress)	\
+static u8 __nhc##_val[_idlen];			\
+static u8 __nhc##_mask[_idlen];			\
+static struct lowpan_nhc __nhc = {		\
+	.name		= _name,		\
+	.nexthdr	= _nexthdr,		\
+	.nexthdrlen	= _hdrlen,		\
+	.id		= __nhc##_val,		\
+	.idmask		= __nhc##_mask,		\
+	.idlen		= _idlen,		\
+	.idsetup	= _idsetup,		\
+	.uncompress	= _uncompress,		\
+	.compress	= _compress,		\
+}
+
+#define module_lowpan_nhc(__nhc)		\
+static int __init __nhc##_init(void)		\
+{						\
+	return lowpan_nhc_add(&(__nhc));	\
+}						\
+module_init(__nhc##_init);			\
+static void __exit __nhc##_exit(void)		\
+{						\
+	lowpan_nhc_del(&(__nhc));		\
+}						\
+module_exit(__nhc##_exit);
+
+/**
+ * struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation
+ *
+ * @node: holder for the rbtree.
+ * @name: name of the specific next header compression
+ * @nexthdr: next header value of the protocol which should be compressed.
+ * @nexthdrlen: ipv6 nexthdr len for the reserved space.
+ * @id: array for nhc id. Note this need to be in network byteorder.
+ * @mask: array for nhc id mask. Note this need to be in network byteorder.
+ * @len: the length of the next header id and mask.
+ * @setup: callback to setup fill the next header id value and mask.
+ * @compress: callback to do the header compression.
+ * @uncompress: callback to do the header uncompression.
+ */
+struct lowpan_nhc {
+	struct rb_node	node;
+	const char	*name;
+	const u8	nexthdr;
+	const size_t	nexthdrlen;
+	u8		*id;
+	u8		*idmask;
+	const size_t	idlen;
+
+	void		(*idsetup)(struct lowpan_nhc *nhc);
+	int		(*uncompress)(struct sk_buff *skb, size_t needed);
+	int		(*compress)(struct sk_buff *skb, u8 **hc_ptr);
+};
+
+/**
+ * lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr.
+ *
+ * @nexthdr: ipv6 nexthdr value.
+ */
+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 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.
+ */
+int lowpan_nhc_check_compression(struct sk_buff *skb,
+				 const struct ipv6hdr *hdr, u8 **hc_ptr);
+
+/**
+ * lowpan_nhc_do_compression - calling compress callback for nhc
+ *
+ * @skb: skb of 6LoWPAN header to read nhc and replace header.
+ * @hdr: ipv6hdr to set the nexthdr value
+ * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
+ *	    replaced header.
+ */
+int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
+			      u8 **hc_ptr);
+
+/**
+ * lowpan_nhc_do_uncompression - calling uncompress callback for nhc
+ *
+ * @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions.
+ * @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value.
+ * @dev: netdevice for print logging information.
+ * @hdr: ipv6hdr for setting nexthdr value.
+ */
+int lowpan_nhc_do_uncompression(struct sk_buff *skb,
+				const struct net_device *dev,
+				struct ipv6hdr *hdr);
+
+/**
+ * lowpan_nhc_add - register a next header compression to framework
+ *
+ * @nhc: nhc which should be add.
+ */
+int lowpan_nhc_add(struct lowpan_nhc *nhc);
+
+/**
+ * lowpan_nhc_del - delete a next header compression from framework
+ *
+ * @nhc: nhc which should be delete.
+ */
+void lowpan_nhc_del(struct lowpan_nhc *nhc);
+
+/**
+ * lowpan_nhc_init - adding all default nhcs
+ */
+void lowpan_nhc_init(void);
+
+#endif /* __6LOWPAN_NHC_H */
diff --git a/net/6lowpan/nhc_dest.c b/net/6lowpan/nhc_dest.c
new file mode 100644
index 000000000..4768a9459
--- /dev/null
+++ b/net/6lowpan/nhc_dest.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN IPv6 Destination Options Header compression according to
+ *	RFC6282
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_NHC_DEST_IDLEN	1
+#define LOWPAN_NHC_DEST_ID_0	0xe6
+#define LOWPAN_NHC_DEST_MASK_0	0xfe
+
+static void dest_nhid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_NHC_DEST_ID_0;
+	nhc->idmask[0] = LOWPAN_NHC_DEST_MASK_0;
+}
+
+LOWPAN_NHC(nhc_dest, "RFC6282 Destination Options", NEXTHDR_DEST, 0,
+	   dest_nhid_setup, LOWPAN_NHC_DEST_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(nhc_dest);
+MODULE_DESCRIPTION("6LoWPAN next header RFC6282 Destination Options compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_fragment.c b/net/6lowpan/nhc_fragment.c
new file mode 100644
index 000000000..be85f0771
--- /dev/null
+++ b/net/6lowpan/nhc_fragment.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN IPv6 Fragment Header compression according to RFC6282
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_NHC_FRAGMENT_IDLEN	1
+#define LOWPAN_NHC_FRAGMENT_ID_0	0xe4
+#define LOWPAN_NHC_FRAGMENT_MASK_0	0xfe
+
+static void fragment_nhid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_NHC_FRAGMENT_ID_0;
+	nhc->idmask[0] = LOWPAN_NHC_FRAGMENT_MASK_0;
+}
+
+LOWPAN_NHC(nhc_fragment, "RFC6282 Fragment", NEXTHDR_FRAGMENT, 0,
+	   fragment_nhid_setup, LOWPAN_NHC_FRAGMENT_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(nhc_fragment);
+MODULE_DESCRIPTION("6LoWPAN next header RFC6282 Fragment compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_ghc_ext_dest.c b/net/6lowpan/nhc_ghc_ext_dest.c
new file mode 100644
index 000000000..a9137f173
--- /dev/null
+++ b/net/6lowpan/nhc_ghc_ext_dest.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN Extension Header compression according to RFC7400
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_GHC_EXT_DEST_IDLEN	1
+#define LOWPAN_GHC_EXT_DEST_ID_0	0xb6
+#define LOWPAN_GHC_EXT_DEST_MASK_0	0xfe
+
+static void dest_ghid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_GHC_EXT_DEST_ID_0;
+	nhc->idmask[0] = LOWPAN_GHC_EXT_DEST_MASK_0;
+}
+
+LOWPAN_NHC(ghc_ext_dest, "RFC7400 Destination Extension Header", NEXTHDR_DEST,
+	   0, dest_ghid_setup, LOWPAN_GHC_EXT_DEST_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(ghc_ext_dest);
+MODULE_DESCRIPTION("6LoWPAN generic header destination extension compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_ghc_ext_frag.c b/net/6lowpan/nhc_ghc_ext_frag.c
new file mode 100644
index 000000000..d49b74591
--- /dev/null
+++ b/net/6lowpan/nhc_ghc_ext_frag.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN Extension Header compression according to RFC7400
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_GHC_EXT_FRAG_IDLEN	1
+#define LOWPAN_GHC_EXT_FRAG_ID_0	0xb4
+#define LOWPAN_GHC_EXT_FRAG_MASK_0	0xfe
+
+static void frag_ghid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_GHC_EXT_FRAG_ID_0;
+	nhc->idmask[0] = LOWPAN_GHC_EXT_FRAG_MASK_0;
+}
+
+LOWPAN_NHC(ghc_ext_frag, "RFC7400 Fragmentation Extension Header",
+	   NEXTHDR_FRAGMENT, 0, frag_ghid_setup,
+	   LOWPAN_GHC_EXT_FRAG_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(ghc_ext_frag);
+MODULE_DESCRIPTION("6LoWPAN generic header fragmentation extension compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_ghc_ext_hop.c b/net/6lowpan/nhc_ghc_ext_hop.c
new file mode 100644
index 000000000..3beedf514
--- /dev/null
+++ b/net/6lowpan/nhc_ghc_ext_hop.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN Extension Header compression according to RFC7400
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_GHC_EXT_HOP_IDLEN	1
+#define LOWPAN_GHC_EXT_HOP_ID_0		0xb0
+#define LOWPAN_GHC_EXT_HOP_MASK_0	0xfe
+
+static void hop_ghid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_GHC_EXT_HOP_ID_0;
+	nhc->idmask[0] = LOWPAN_GHC_EXT_HOP_MASK_0;
+}
+
+LOWPAN_NHC(ghc_ext_hop, "RFC7400 Hop-by-Hop Extension Header", NEXTHDR_HOP, 0,
+	   hop_ghid_setup, LOWPAN_GHC_EXT_HOP_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(ghc_ext_hop);
+MODULE_DESCRIPTION("6LoWPAN generic header hop-by-hop extension compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_ghc_ext_route.c b/net/6lowpan/nhc_ghc_ext_route.c
new file mode 100644
index 000000000..70dc0ea3c
--- /dev/null
+++ b/net/6lowpan/nhc_ghc_ext_route.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN Extension Header compression according to RFC7400
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_GHC_EXT_ROUTE_IDLEN	1
+#define LOWPAN_GHC_EXT_ROUTE_ID_0	0xb2
+#define LOWPAN_GHC_EXT_ROUTE_MASK_0	0xfe
+
+static void route_ghid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_GHC_EXT_ROUTE_ID_0;
+	nhc->idmask[0] = LOWPAN_GHC_EXT_ROUTE_MASK_0;
+}
+
+LOWPAN_NHC(ghc_ext_route, "RFC7400 Routing Extension Header", NEXTHDR_ROUTING,
+	   0, route_ghid_setup, LOWPAN_GHC_EXT_ROUTE_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(ghc_ext_route);
+MODULE_DESCRIPTION("6LoWPAN generic header routing extension compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_ghc_icmpv6.c b/net/6lowpan/nhc_ghc_icmpv6.c
new file mode 100644
index 000000000..339ceffc2
--- /dev/null
+++ b/net/6lowpan/nhc_ghc_icmpv6.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN ICMPv6 compression according to RFC7400
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_GHC_ICMPV6_IDLEN		1
+#define LOWPAN_GHC_ICMPV6_ID_0		0xdf
+#define LOWPAN_GHC_ICMPV6_MASK_0	0xff
+
+static void icmpv6_ghid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_GHC_ICMPV6_ID_0;
+	nhc->idmask[0] = LOWPAN_GHC_ICMPV6_MASK_0;
+}
+
+LOWPAN_NHC(ghc_icmpv6, "RFC7400 ICMPv6", NEXTHDR_ICMP, 0,
+	   icmpv6_ghid_setup, LOWPAN_GHC_ICMPV6_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(ghc_icmpv6);
+MODULE_DESCRIPTION("6LoWPAN generic header ICMPv6 compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_ghc_udp.c b/net/6lowpan/nhc_ghc_udp.c
new file mode 100644
index 000000000..f47fec601
--- /dev/null
+++ b/net/6lowpan/nhc_ghc_udp.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN UDP compression according to RFC7400
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_GHC_UDP_IDLEN	1
+#define LOWPAN_GHC_UDP_ID_0	0xd0
+#define LOWPAN_GHC_UDP_MASK_0	0xf8
+
+static void udp_ghid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_GHC_UDP_ID_0;
+	nhc->idmask[0] = LOWPAN_GHC_UDP_MASK_0;
+}
+
+LOWPAN_NHC(ghc_udp, "RFC7400 UDP", NEXTHDR_UDP, 0,
+	   udp_ghid_setup, LOWPAN_GHC_UDP_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(ghc_udp);
+MODULE_DESCRIPTION("6LoWPAN generic header UDP compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_hop.c b/net/6lowpan/nhc_hop.c
new file mode 100644
index 000000000..158fc1906
--- /dev/null
+++ b/net/6lowpan/nhc_hop.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN IPv6 Hop-by-Hop Options Header compression according to RFC6282
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_NHC_HOP_IDLEN	1
+#define LOWPAN_NHC_HOP_ID_0	0xe0
+#define LOWPAN_NHC_HOP_MASK_0	0xfe
+
+static void hop_nhid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_NHC_HOP_ID_0;
+	nhc->idmask[0] = LOWPAN_NHC_HOP_MASK_0;
+}
+
+LOWPAN_NHC(nhc_hop, "RFC6282 Hop-by-Hop Options", NEXTHDR_HOP, 0,
+	   hop_nhid_setup, LOWPAN_NHC_HOP_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(nhc_hop);
+MODULE_DESCRIPTION("6LoWPAN next header RFC6282 Hop-by-Hop Options compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_ipv6.c b/net/6lowpan/nhc_ipv6.c
new file mode 100644
index 000000000..08b7589e5
--- /dev/null
+++ b/net/6lowpan/nhc_ipv6.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN IPv6 Header compression according to RFC6282
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_NHC_IPV6_IDLEN	1
+#define LOWPAN_NHC_IPV6_ID_0	0xee
+#define LOWPAN_NHC_IPV6_MASK_0	0xfe
+
+static void ipv6_nhid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_NHC_IPV6_ID_0;
+	nhc->idmask[0] = LOWPAN_NHC_IPV6_MASK_0;
+}
+
+LOWPAN_NHC(nhc_ipv6, "RFC6282 IPv6", NEXTHDR_IPV6, 0, ipv6_nhid_setup,
+	   LOWPAN_NHC_IPV6_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(nhc_ipv6);
+MODULE_DESCRIPTION("6LoWPAN next header RFC6282 IPv6 compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_mobility.c b/net/6lowpan/nhc_mobility.c
new file mode 100644
index 000000000..ac8fca689
--- /dev/null
+++ b/net/6lowpan/nhc_mobility.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN IPv6 Mobility Header compression according to RFC6282
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_NHC_MOBILITY_IDLEN	1
+#define LOWPAN_NHC_MOBILITY_ID_0	0xe8
+#define LOWPAN_NHC_MOBILITY_MASK_0	0xfe
+
+static void mobility_nhid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_NHC_MOBILITY_ID_0;
+	nhc->idmask[0] = LOWPAN_NHC_MOBILITY_MASK_0;
+}
+
+LOWPAN_NHC(nhc_mobility, "RFC6282 Mobility", NEXTHDR_MOBILITY, 0,
+	   mobility_nhid_setup, LOWPAN_NHC_MOBILITY_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(nhc_mobility);
+MODULE_DESCRIPTION("6LoWPAN next header RFC6282 Mobility compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_routing.c b/net/6lowpan/nhc_routing.c
new file mode 100644
index 000000000..1c174023d
--- /dev/null
+++ b/net/6lowpan/nhc_routing.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN IPv6 Routing Header compression according to RFC6282
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_NHC_ROUTING_IDLEN	1
+#define LOWPAN_NHC_ROUTING_ID_0		0xe2
+#define LOWPAN_NHC_ROUTING_MASK_0	0xfe
+
+static void routing_nhid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_NHC_ROUTING_ID_0;
+	nhc->idmask[0] = LOWPAN_NHC_ROUTING_MASK_0;
+}
+
+LOWPAN_NHC(nhc_routing, "RFC6282 Routing", NEXTHDR_ROUTING, 0,
+	   routing_nhid_setup, LOWPAN_NHC_ROUTING_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(nhc_routing);
+MODULE_DESCRIPTION("6LoWPAN next header RFC6282 Routing compression");
+MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/nhc_udp.c b/net/6lowpan/nhc_udp.c
new file mode 100644
index 000000000..8a3507524
--- /dev/null
+++ b/net/6lowpan/nhc_udp.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	6LoWPAN IPv6 UDP compression according to RFC6282
+ *
+ *	Authors:
+ *	Alexander Aring	<aar@pengutronix.de>
+ *
+ *	Orignal written by:
+ *	Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
+ *	Jon Smirl <jonsmirl@gmail.com>
+ */
+
+#include "nhc.h"
+
+#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)
+{
+	u8 tmp = 0, val = 0;
+	struct udphdr uh;
+	bool fail;
+	int err;
+
+	fail = lowpan_fetch_skb(skb, &tmp, sizeof(tmp));
+
+	pr_debug("UDP header uncompression\n");
+	switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
+	case LOWPAN_NHC_UDP_CS_P_00:
+		fail |= lowpan_fetch_skb(skb, &uh.source, sizeof(uh.source));
+		fail |= lowpan_fetch_skb(skb, &uh.dest, sizeof(uh.dest));
+		break;
+	case LOWPAN_NHC_UDP_CS_P_01:
+		fail |= lowpan_fetch_skb(skb, &uh.source, sizeof(uh.source));
+		fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
+		uh.dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
+		break;
+	case LOWPAN_NHC_UDP_CS_P_10:
+		fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
+		uh.source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
+		fail |= lowpan_fetch_skb(skb, &uh.dest, sizeof(uh.dest));
+		break;
+	case LOWPAN_NHC_UDP_CS_P_11:
+		fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
+		uh.source = htons(LOWPAN_NHC_UDP_4BIT_PORT + (val >> 4));
+		uh.dest = htons(LOWPAN_NHC_UDP_4BIT_PORT + (val & 0x0f));
+		break;
+	default:
+		BUG();
+	}
+
+	pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
+		 ntohs(uh.source), ntohs(uh.dest));
+
+	/* checksum */
+	if (tmp & LOWPAN_NHC_UDP_CS_C) {
+		pr_debug_ratelimited("checksum elided currently not supported\n");
+		fail = true;
+	} else {
+		fail |= lowpan_fetch_skb(skb, &uh.check, sizeof(uh.check));
+	}
+
+	if (fail)
+		return -EINVAL;
+
+	/* UDP length needs to be infered from the lower layers
+	 * here, we obtain the hint from the remaining size of the
+	 * frame
+	 */
+	switch (lowpan_dev(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
+	 * header
+	 */
+	err = skb_cow(skb, needed);
+	if (unlikely(err))
+		return err;
+
+	skb_push(skb, sizeof(struct udphdr));
+	skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));
+
+	return 0;
+}
+
+static int udp_compress(struct sk_buff *skb, u8 **hc_ptr)
+{
+	const struct udphdr *uh = udp_hdr(skb);
+	u8 tmp;
+
+	if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) ==
+	     LOWPAN_NHC_UDP_4BIT_PORT) &&
+	    ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) ==
+	     LOWPAN_NHC_UDP_4BIT_PORT)) {
+		pr_debug("UDP header: both ports compression to 4 bits\n");
+		/* compression value */
+		tmp = LOWPAN_NHC_UDP_CS_P_11;
+		lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
+		/* source and destination port */
+		tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT +
+		      ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4);
+		lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
+	} else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) ==
+			LOWPAN_NHC_UDP_8BIT_PORT) {
+		pr_debug("UDP header: remove 8 bits of dest\n");
+		/* compression value */
+		tmp = LOWPAN_NHC_UDP_CS_P_01;
+		lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
+		/* source port */
+		lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source));
+		/* destination port */
+		tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT;
+		lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
+	} else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) ==
+			LOWPAN_NHC_UDP_8BIT_PORT) {
+		pr_debug("UDP header: remove 8 bits of source\n");
+		/* compression value */
+		tmp = LOWPAN_NHC_UDP_CS_P_10;
+		lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
+		/* source port */
+		tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT;
+		lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
+		/* destination port */
+		lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest));
+	} else {
+		pr_debug("UDP header: can't compress\n");
+		/* compression value */
+		tmp = LOWPAN_NHC_UDP_CS_P_00;
+		lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
+		/* source port */
+		lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source));
+		/* destination port */
+		lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest));
+	}
+
+	/* checksum is always inline */
+	lowpan_push_hc_data(hc_ptr, &uh->check, sizeof(uh->check));
+
+	return 0;
+}
+
+static void udp_nhid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_NHC_UDP_ID;
+	nhc->idmask[0] = LOWPAN_NHC_UDP_MASK;
+}
+
+LOWPAN_NHC(nhc_udp, "RFC6282 UDP", NEXTHDR_UDP, sizeof(struct udphdr),
+	   udp_nhid_setup, LOWPAN_NHC_UDP_IDLEN, udp_uncompress, udp_compress);
+
+module_lowpan_nhc(nhc_udp);
+MODULE_DESCRIPTION("6LoWPAN next header RFC6282 UDP compression");
+MODULE_LICENSE("GPL");