Adding upstream version 4.19.249.upstream/4.19.249

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

18 files changed, 10740 insertions, 0 deletions

diff --git a/net/decnet/Kconfig b/net/decnet/Kconfig
new file mode 100644
index 000000000..dcc74956b
--- /dev/null
+++ b/net/decnet/Kconfig
@@ -0,0 +1,42 @@
+#
+# DECnet configuration
+#
+config DECNET
+	tristate "DECnet Support"
+	---help---
+	  The DECnet networking protocol was used in many products made by
+	  Digital (now Compaq).  It provides reliable stream and sequenced
+	  packet communications over which run a variety of services similar
+	  to those which run over TCP/IP.
+
+	  To find some tools to use with the kernel layer support, please
+	  look at Patrick Caulfield's web site:
+	  <http://linux-decnet.sourceforge.net/>.
+
+	  More detailed documentation is available in
+	  <file:Documentation/networking/decnet.txt>.
+
+	  Be sure to say Y to "/proc file system support" and "Sysctl support"
+	  below when using DECnet, since you will need sysctl support to aid
+	  in configuration at run time.
+
+	  The DECnet code is also available as a module ( = code which can be
+	  inserted in and removed from the running kernel whenever you want).
+	  The module is called decnet.
+
+config DECNET_ROUTER
+	bool "DECnet: router support"
+	depends on DECNET
+	select FIB_RULES
+	---help---
+	  Add support for turning your DECnet Endnode into a level 1 or 2
+	  router.  This is an experimental, but functional option.  If you
+	  do say Y here, then make sure that you also say Y to "Kernel/User
+	  network link driver", "Routing messages" and "Network packet
+	  filtering".  The first two are required to allow configuration via
+	  rtnetlink (you will need Alexey Kuznetsov's iproute2 package
+	  from <ftp://ftp.tux.org/pub/net/ip-routing/>). The "Network packet
+	  filtering" option will be required for the forthcoming routing daemon
+	  to work.
+
+	  See <file:Documentation/networking/decnet.txt> for more information.
diff --git a/net/decnet/Makefile b/net/decnet/Makefile
new file mode 100644
index 000000000..07b38e441
--- /dev/null
+++ b/net/decnet/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_DECNET) += decnet.o
+
+decnet-y := af_decnet.o dn_nsp_in.o dn_nsp_out.o \
+	    dn_route.o dn_dev.o dn_neigh.o dn_timer.o
+decnet-$(CONFIG_DECNET_ROUTER) += dn_fib.o dn_rules.o dn_table.o
+decnet-y += sysctl_net_decnet.o
+
+obj-$(CONFIG_NETFILTER) += netfilter/
diff --git a/net/decnet/README b/net/decnet/README
new file mode 100644
index 000000000..60e7ec88c
--- /dev/null
+++ b/net/decnet/README
@@ -0,0 +1,8 @@
+                       Linux DECnet Project
+                      ======================
+
+The documentation for this kernel subsystem is available in the
+Documentation/networking subdirectory of this distribution and also
+on line at http://www.chygwyn.com/DECnet/
+
+Steve Whitehouse <SteveW@ACM.org>
diff --git a/net/decnet/TODO b/net/decnet/TODO
new file mode 100644
index 000000000..358e9eb49
--- /dev/null
+++ b/net/decnet/TODO
@@ -0,0 +1,40 @@
+Steve's quick list of things that need finishing off:
+[they are in no particular order and range from the trivial to the long winded]
+
+ o Proper timeouts on each neighbour (in routing mode) rather than
+   just the 60 second On-Ethernet cache value.
+
+ o Support for X.25 linklayer
+
+ o Support for DDCMP link layer
+
+ o The DDCMP device itself
+
+ o PPP support (rfc1762)
+
+ o Lots of testing with real applications
+
+ o Verify errors etc. against POSIX 1003.1g (draft)
+
+ o Using send/recvmsg() to get at connect/disconnect data (POSIX 1003.1g)
+   [maybe this should be done at socket level... the control data in the
+    send/recvmsg() calls should simply be a vector of set/getsockopt()
+    calls]
+
+ o check MSG_CTRUNC is set where it should be.
+
+ o Find all the commonality between DECnet and IPv4 routing code and extract
+   it into a small library of routines. [probably a project for 2.7.xx]
+
+ o Add perfect socket hashing - an idea suggested by Paul Koning. Currently
+   we have a half-way house scheme which seems to work reasonably well, but
+   the full scheme is still worth implementing, its not not top of my list
+   right now.
+
+ o Add session control message flow control
+
+ o Add NSP message flow control
+
+ o DECnet sendpages() function
+
+ o AIO for DECnet
diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
new file mode 100644
index 000000000..cc7077105
--- /dev/null
+++ b/net/decnet/af_decnet.c
@@ -0,0 +1,2408 @@
+
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Socket Layer Interface
+ *
+ * Authors:     Eduardo Marcelo Serrat <emserrat@geocities.com>
+ *              Patrick Caulfield <patrick@pandh.demon.co.uk>
+ *
+ * Changes:
+ *        Steve Whitehouse: Copied from Eduardo Serrat and Patrick Caulfield's
+ *                          version of the code. Original copyright preserved
+ *                          below.
+ *        Steve Whitehouse: Some bug fixes, cleaning up some code to make it
+ *                          compatible with my routing layer.
+ *        Steve Whitehouse: Merging changes from Eduardo Serrat and Patrick
+ *                          Caulfield.
+ *        Steve Whitehouse: Further bug fixes, checking module code still works
+ *                          with new routing layer.
+ *        Steve Whitehouse: Additional set/get_sockopt() calls.
+ *        Steve Whitehouse: Fixed TIOCINQ ioctl to be same as Eduardo's new
+ *                          code.
+ *        Steve Whitehouse: recvmsg() changed to try and behave in a POSIX like
+ *                          way. Didn't manage it entirely, but its better.
+ *        Steve Whitehouse: ditto for sendmsg().
+ *        Steve Whitehouse: A selection of bug fixes to various things.
+ *        Steve Whitehouse: Added TIOCOUTQ ioctl.
+ *        Steve Whitehouse: Fixes to username2sockaddr & sockaddr2username.
+ *        Steve Whitehouse: Fixes to connect() error returns.
+ *       Patrick Caulfield: Fixes to delayed acceptance logic.
+ *         David S. Miller: New socket locking
+ *        Steve Whitehouse: Socket list hashing/locking
+ *         Arnaldo C. Melo: use capable, not suser
+ *        Steve Whitehouse: Removed unused code. Fix to use sk->allocation
+ *                          when required.
+ *       Patrick Caulfield: /proc/net/decnet now has object name/number
+ *        Steve Whitehouse: Fixed local port allocation, hashed sk list
+ *          Matthew Wilcox: Fixes for dn_ioctl()
+ *        Steve Whitehouse: New connect/accept logic to allow timeouts and
+ *                          prepare for sendpage etc.
+ */
+
+
+/******************************************************************************
+    (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    any later version.
+
+    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.
+
+HISTORY:
+
+Version           Kernel     Date       Author/Comments
+-------           ------     ----       ---------------
+Version 0.0.1     2.0.30    01-dic-97	Eduardo Marcelo Serrat
+					(emserrat@geocities.com)
+
+					First Development of DECnet Socket La-
+					yer for Linux. Only supports outgoing
+					connections.
+
+Version 0.0.2	  2.1.105   20-jun-98   Patrick J. Caulfield
+					(patrick@pandh.demon.co.uk)
+
+					Port to new kernel development version.
+
+Version 0.0.3     2.1.106   25-jun-98   Eduardo Marcelo Serrat
+					(emserrat@geocities.com)
+					_
+					Added support for incoming connections
+					so we can start developing server apps
+					on Linux.
+					-
+					Module Support
+Version 0.0.4     2.1.109   21-jul-98   Eduardo Marcelo Serrat
+				       (emserrat@geocities.com)
+				       _
+					Added support for X11R6.4. Now we can
+					use DECnet transport for X on Linux!!!
+				       -
+Version 0.0.5    2.1.110   01-aug-98   Eduardo Marcelo Serrat
+				       (emserrat@geocities.com)
+				       Removed bugs on flow control
+				       Removed bugs on incoming accessdata
+				       order
+				       -
+Version 0.0.6    2.1.110   07-aug-98   Eduardo Marcelo Serrat
+				       dn_recvmsg fixes
+
+					Patrick J. Caulfield
+				       dn_bind fixes
+*******************************************************************************/
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/inet.h>
+#include <linux/route.h>
+#include <linux/netfilter.h>
+#include <linux/seq_file.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <net/flow.h>
+#include <asm/ioctls.h>
+#include <linux/capability.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/jiffies.h>
+#include <net/net_namespace.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/fib_rules.h>
+#include <net/tcp.h>
+#include <net/dn.h>
+#include <net/dn_nsp.h>
+#include <net/dn_dev.h>
+#include <net/dn_route.h>
+#include <net/dn_fib.h>
+#include <net/dn_neigh.h>
+
+struct dn_sock {
+	struct sock sk;
+	struct dn_scp scp;
+};
+
+static void dn_keepalive(struct sock *sk);
+
+#define DN_SK_HASH_SHIFT 8
+#define DN_SK_HASH_SIZE (1 << DN_SK_HASH_SHIFT)
+#define DN_SK_HASH_MASK (DN_SK_HASH_SIZE - 1)
+
+
+static const struct proto_ops dn_proto_ops;
+static DEFINE_RWLOCK(dn_hash_lock);
+static struct hlist_head dn_sk_hash[DN_SK_HASH_SIZE];
+static struct hlist_head dn_wild_sk;
+static atomic_long_t decnet_memory_allocated;
+
+static int __dn_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen, int flags);
+static int __dn_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen, int flags);
+
+static struct hlist_head *dn_find_list(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	if (scp->addr.sdn_flags & SDF_WILD)
+		return hlist_empty(&dn_wild_sk) ? &dn_wild_sk : NULL;
+
+	return &dn_sk_hash[le16_to_cpu(scp->addrloc) & DN_SK_HASH_MASK];
+}
+
+/*
+ * Valid ports are those greater than zero and not already in use.
+ */
+static int check_port(__le16 port)
+{
+	struct sock *sk;
+
+	if (port == 0)
+		return -1;
+
+	sk_for_each(sk, &dn_sk_hash[le16_to_cpu(port) & DN_SK_HASH_MASK]) {
+		struct dn_scp *scp = DN_SK(sk);
+		if (scp->addrloc == port)
+			return -1;
+	}
+	return 0;
+}
+
+static unsigned short port_alloc(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+static unsigned short port = 0x2000;
+	unsigned short i_port = port;
+
+	while(check_port(cpu_to_le16(++port)) != 0) {
+		if (port == i_port)
+			return 0;
+	}
+
+	scp->addrloc = cpu_to_le16(port);
+
+	return 1;
+}
+
+/*
+ * Since this is only ever called from user
+ * level, we don't need a write_lock() version
+ * of this.
+ */
+static int dn_hash_sock(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct hlist_head *list;
+	int rv = -EUSERS;
+
+	BUG_ON(sk_hashed(sk));
+
+	write_lock_bh(&dn_hash_lock);
+
+	if (!scp->addrloc && !port_alloc(sk))
+		goto out;
+
+	rv = -EADDRINUSE;
+	if ((list = dn_find_list(sk)) == NULL)
+		goto out;
+
+	sk_add_node(sk, list);
+	rv = 0;
+out:
+	write_unlock_bh(&dn_hash_lock);
+	return rv;
+}
+
+static void dn_unhash_sock(struct sock *sk)
+{
+	write_lock(&dn_hash_lock);
+	sk_del_node_init(sk);
+	write_unlock(&dn_hash_lock);
+}
+
+static void dn_unhash_sock_bh(struct sock *sk)
+{
+	write_lock_bh(&dn_hash_lock);
+	sk_del_node_init(sk);
+	write_unlock_bh(&dn_hash_lock);
+}
+
+static struct hlist_head *listen_hash(struct sockaddr_dn *addr)
+{
+	int i;
+	unsigned int hash = addr->sdn_objnum;
+
+	if (hash == 0) {
+		hash = addr->sdn_objnamel;
+		for(i = 0; i < le16_to_cpu(addr->sdn_objnamel); i++) {
+			hash ^= addr->sdn_objname[i];
+			hash ^= (hash << 3);
+		}
+	}
+
+	return &dn_sk_hash[hash & DN_SK_HASH_MASK];
+}
+
+/*
+ * Called to transform a socket from bound (i.e. with a local address)
+ * into a listening socket (doesn't need a local port number) and rehashes
+ * based upon the object name/number.
+ */
+static void dn_rehash_sock(struct sock *sk)
+{
+	struct hlist_head *list;
+	struct dn_scp *scp = DN_SK(sk);
+
+	if (scp->addr.sdn_flags & SDF_WILD)
+		return;
+
+	write_lock_bh(&dn_hash_lock);
+	sk_del_node_init(sk);
+	DN_SK(sk)->addrloc = 0;
+	list = listen_hash(&DN_SK(sk)->addr);
+	sk_add_node(sk, list);
+	write_unlock_bh(&dn_hash_lock);
+}
+
+int dn_sockaddr2username(struct sockaddr_dn *sdn, unsigned char *buf, unsigned char type)
+{
+	int len = 2;
+
+	*buf++ = type;
+
+	switch (type) {
+	case 0:
+		*buf++ = sdn->sdn_objnum;
+		break;
+	case 1:
+		*buf++ = 0;
+		*buf++ = le16_to_cpu(sdn->sdn_objnamel);
+		memcpy(buf, sdn->sdn_objname, le16_to_cpu(sdn->sdn_objnamel));
+		len = 3 + le16_to_cpu(sdn->sdn_objnamel);
+		break;
+	case 2:
+		memset(buf, 0, 5);
+		buf += 5;
+		*buf++ = le16_to_cpu(sdn->sdn_objnamel);
+		memcpy(buf, sdn->sdn_objname, le16_to_cpu(sdn->sdn_objnamel));
+		len = 7 + le16_to_cpu(sdn->sdn_objnamel);
+		break;
+	}
+
+	return len;
+}
+
+/*
+ * On reception of usernames, we handle types 1 and 0 for destination
+ * addresses only. Types 2 and 4 are used for source addresses, but the
+ * UIC, GIC are ignored and they are both treated the same way. Type 3
+ * is never used as I've no idea what its purpose might be or what its
+ * format is.
+ */
+int dn_username2sockaddr(unsigned char *data, int len, struct sockaddr_dn *sdn, unsigned char *fmt)
+{
+	unsigned char type;
+	int size = len;
+	int namel = 12;
+
+	sdn->sdn_objnum = 0;
+	sdn->sdn_objnamel = cpu_to_le16(0);
+	memset(sdn->sdn_objname, 0, DN_MAXOBJL);
+
+	if (len < 2)
+		return -1;
+
+	len -= 2;
+	*fmt = *data++;
+	type = *data++;
+
+	switch (*fmt) {
+	case 0:
+		sdn->sdn_objnum = type;
+		return 2;
+	case 1:
+		namel = 16;
+		break;
+	case 2:
+		len  -= 4;
+		data += 4;
+		break;
+	case 4:
+		len  -= 8;
+		data += 8;
+		break;
+	default:
+		return -1;
+	}
+
+	len -= 1;
+
+	if (len < 0)
+		return -1;
+
+	sdn->sdn_objnamel = cpu_to_le16(*data++);
+	len -= le16_to_cpu(sdn->sdn_objnamel);
+
+	if ((len < 0) || (le16_to_cpu(sdn->sdn_objnamel) > namel))
+		return -1;
+
+	memcpy(sdn->sdn_objname, data, le16_to_cpu(sdn->sdn_objnamel));
+
+	return size - len;
+}
+
+struct sock *dn_sklist_find_listener(struct sockaddr_dn *addr)
+{
+	struct hlist_head *list = listen_hash(addr);
+	struct sock *sk;
+
+	read_lock(&dn_hash_lock);
+	sk_for_each(sk, list) {
+		struct dn_scp *scp = DN_SK(sk);
+		if (sk->sk_state != TCP_LISTEN)
+			continue;
+		if (scp->addr.sdn_objnum) {
+			if (scp->addr.sdn_objnum != addr->sdn_objnum)
+				continue;
+		} else {
+			if (addr->sdn_objnum)
+				continue;
+			if (scp->addr.sdn_objnamel != addr->sdn_objnamel)
+				continue;
+			if (memcmp(scp->addr.sdn_objname, addr->sdn_objname, le16_to_cpu(addr->sdn_objnamel)) != 0)
+				continue;
+		}
+		sock_hold(sk);
+		read_unlock(&dn_hash_lock);
+		return sk;
+	}
+
+	sk = sk_head(&dn_wild_sk);
+	if (sk) {
+		if (sk->sk_state == TCP_LISTEN)
+			sock_hold(sk);
+		else
+			sk = NULL;
+	}
+
+	read_unlock(&dn_hash_lock);
+	return sk;
+}
+
+struct sock *dn_find_by_skb(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct sock *sk;
+	struct dn_scp *scp;
+
+	read_lock(&dn_hash_lock);
+	sk_for_each(sk, &dn_sk_hash[le16_to_cpu(cb->dst_port) & DN_SK_HASH_MASK]) {
+		scp = DN_SK(sk);
+		if (cb->src != dn_saddr2dn(&scp->peer))
+			continue;
+		if (cb->dst_port != scp->addrloc)
+			continue;
+		if (scp->addrrem && (cb->src_port != scp->addrrem))
+			continue;
+		sock_hold(sk);
+		goto found;
+	}
+	sk = NULL;
+found:
+	read_unlock(&dn_hash_lock);
+	return sk;
+}
+
+
+
+static void dn_destruct(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	skb_queue_purge(&scp->data_xmit_queue);
+	skb_queue_purge(&scp->other_xmit_queue);
+	skb_queue_purge(&scp->other_receive_queue);
+
+	dst_release(rcu_dereference_check(sk->sk_dst_cache, 1));
+}
+
+static unsigned long dn_memory_pressure;
+
+static void dn_enter_memory_pressure(struct sock *sk)
+{
+	if (!dn_memory_pressure) {
+		dn_memory_pressure = 1;
+	}
+}
+
+static struct proto dn_proto = {
+	.name			= "NSP",
+	.owner			= THIS_MODULE,
+	.enter_memory_pressure	= dn_enter_memory_pressure,
+	.memory_pressure	= &dn_memory_pressure,
+	.memory_allocated	= &decnet_memory_allocated,
+	.sysctl_mem		= sysctl_decnet_mem,
+	.sysctl_wmem		= sysctl_decnet_wmem,
+	.sysctl_rmem		= sysctl_decnet_rmem,
+	.max_header		= DN_MAX_NSP_DATA_HEADER + 64,
+	.obj_size		= sizeof(struct dn_sock),
+};
+
+static struct sock *dn_alloc_sock(struct net *net, struct socket *sock, gfp_t gfp, int kern)
+{
+	struct dn_scp *scp;
+	struct sock *sk = sk_alloc(net, PF_DECnet, gfp, &dn_proto, kern);
+
+	if  (!sk)
+		goto out;
+
+	if (sock)
+		sock->ops = &dn_proto_ops;
+	sock_init_data(sock, sk);
+
+	sk->sk_backlog_rcv = dn_nsp_backlog_rcv;
+	sk->sk_destruct    = dn_destruct;
+	sk->sk_no_check_tx = 1;
+	sk->sk_family      = PF_DECnet;
+	sk->sk_protocol    = 0;
+	sk->sk_allocation  = gfp;
+	sk->sk_sndbuf	   = sysctl_decnet_wmem[1];
+	sk->sk_rcvbuf	   = sysctl_decnet_rmem[1];
+
+	/* Initialization of DECnet Session Control Port		*/
+	scp = DN_SK(sk);
+	scp->state	= DN_O;		/* Open			*/
+	scp->numdat	= 1;		/* Next data seg to tx	*/
+	scp->numoth	= 1;		/* Next oth data to tx  */
+	scp->ackxmt_dat = 0;		/* Last data seg ack'ed */
+	scp->ackxmt_oth = 0;		/* Last oth data ack'ed */
+	scp->ackrcv_dat = 0;		/* Highest data ack recv*/
+	scp->ackrcv_oth = 0;		/* Last oth data ack rec*/
+	scp->flowrem_sw = DN_SEND;
+	scp->flowloc_sw = DN_SEND;
+	scp->flowrem_dat = 0;
+	scp->flowrem_oth = 1;
+	scp->flowloc_dat = 0;
+	scp->flowloc_oth = 1;
+	scp->services_rem = 0;
+	scp->services_loc = 1 | NSP_FC_NONE;
+	scp->info_rem = 0;
+	scp->info_loc = 0x03; /* NSP version 4.1 */
+	scp->segsize_rem = 230 - DN_MAX_NSP_DATA_HEADER; /* Default: Updated by remote segsize */
+	scp->nonagle = 0;
+	scp->multi_ireq = 1;
+	scp->accept_mode = ACC_IMMED;
+	scp->addr.sdn_family    = AF_DECnet;
+	scp->peer.sdn_family    = AF_DECnet;
+	scp->accessdata.acc_accl = 5;
+	memcpy(scp->accessdata.acc_acc, "LINUX", 5);
+
+	scp->max_window   = NSP_MAX_WINDOW;
+	scp->snd_window   = NSP_MIN_WINDOW;
+	scp->nsp_srtt     = NSP_INITIAL_SRTT;
+	scp->nsp_rttvar   = NSP_INITIAL_RTTVAR;
+	scp->nsp_rxtshift = 0;
+
+	skb_queue_head_init(&scp->data_xmit_queue);
+	skb_queue_head_init(&scp->other_xmit_queue);
+	skb_queue_head_init(&scp->other_receive_queue);
+
+	scp->persist = 0;
+	scp->persist_fxn = NULL;
+	scp->keepalive = 10 * HZ;
+	scp->keepalive_fxn = dn_keepalive;
+
+	dn_start_slow_timer(sk);
+out:
+	return sk;
+}
+
+/*
+ * Keepalive timer.
+ * FIXME: Should respond to SO_KEEPALIVE etc.
+ */
+static void dn_keepalive(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	/*
+	 * By checking the other_data transmit queue is empty
+	 * we are double checking that we are not sending too
+	 * many of these keepalive frames.
+	 */
+	if (skb_queue_empty(&scp->other_xmit_queue))
+		dn_nsp_send_link(sk, DN_NOCHANGE, 0);
+}
+
+
+/*
+ * Timer for shutdown/destroyed sockets.
+ * When socket is dead & no packets have been sent for a
+ * certain amount of time, they are removed by this
+ * routine. Also takes care of sending out DI & DC
+ * frames at correct times.
+ */
+int dn_destroy_timer(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	scp->persist = dn_nsp_persist(sk);
+
+	switch (scp->state) {
+	case DN_DI:
+		dn_nsp_send_disc(sk, NSP_DISCINIT, 0, GFP_ATOMIC);
+		if (scp->nsp_rxtshift >= decnet_di_count)
+			scp->state = DN_CN;
+		return 0;
+
+	case DN_DR:
+		dn_nsp_send_disc(sk, NSP_DISCINIT, 0, GFP_ATOMIC);
+		if (scp->nsp_rxtshift >= decnet_dr_count)
+			scp->state = DN_DRC;
+		return 0;
+
+	case DN_DN:
+		if (scp->nsp_rxtshift < decnet_dn_count) {
+			/* printk(KERN_DEBUG "dn_destroy_timer: DN\n"); */
+			dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC,
+					 GFP_ATOMIC);
+			return 0;
+		}
+	}
+
+	scp->persist = (HZ * decnet_time_wait);
+
+	if (sk->sk_socket)
+		return 0;
+
+	if (time_after_eq(jiffies, scp->stamp + HZ * decnet_time_wait)) {
+		dn_unhash_sock(sk);
+		sock_put(sk);
+		return 1;
+	}
+
+	return 0;
+}
+
+static void dn_destroy_sock(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	scp->nsp_rxtshift = 0; /* reset back off */
+
+	if (sk->sk_socket) {
+		if (sk->sk_socket->state != SS_UNCONNECTED)
+			sk->sk_socket->state = SS_DISCONNECTING;
+	}
+
+	sk->sk_state = TCP_CLOSE;
+
+	switch (scp->state) {
+	case DN_DN:
+		dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC,
+				 sk->sk_allocation);
+		scp->persist_fxn = dn_destroy_timer;
+		scp->persist = dn_nsp_persist(sk);
+		break;
+	case DN_CR:
+		scp->state = DN_DR;
+		goto disc_reject;
+	case DN_RUN:
+		scp->state = DN_DI;
+		/* fall through */
+	case DN_DI:
+	case DN_DR:
+disc_reject:
+		dn_nsp_send_disc(sk, NSP_DISCINIT, 0, sk->sk_allocation);
+		/* fall through */
+	case DN_NC:
+	case DN_NR:
+	case DN_RJ:
+	case DN_DIC:
+	case DN_CN:
+	case DN_DRC:
+	case DN_CI:
+	case DN_CD:
+		scp->persist_fxn = dn_destroy_timer;
+		scp->persist = dn_nsp_persist(sk);
+		break;
+	default:
+		printk(KERN_DEBUG "DECnet: dn_destroy_sock passed socket in invalid state\n");
+		/* fall through */
+	case DN_O:
+		dn_stop_slow_timer(sk);
+
+		dn_unhash_sock_bh(sk);
+		sock_put(sk);
+
+		break;
+	}
+}
+
+char *dn_addr2asc(__u16 addr, char *buf)
+{
+	unsigned short node, area;
+
+	node = addr & 0x03ff;
+	area = addr >> 10;
+	sprintf(buf, "%hd.%hd", area, node);
+
+	return buf;
+}
+
+
+
+static int dn_create(struct net *net, struct socket *sock, int protocol,
+		     int kern)
+{
+	struct sock *sk;
+
+	if (protocol < 0 || protocol > SK_PROTOCOL_MAX)
+		return -EINVAL;
+
+	if (!net_eq(net, &init_net))
+		return -EAFNOSUPPORT;
+
+	switch (sock->type) {
+	case SOCK_SEQPACKET:
+		if (protocol != DNPROTO_NSP)
+			return -EPROTONOSUPPORT;
+		break;
+	case SOCK_STREAM:
+		break;
+	default:
+		return -ESOCKTNOSUPPORT;
+	}
+
+
+	if ((sk = dn_alloc_sock(net, sock, GFP_KERNEL, kern)) == NULL)
+		return -ENOBUFS;
+
+	sk->sk_protocol = protocol;
+
+	return 0;
+}
+
+
+static int
+dn_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+
+	if (sk) {
+		sock_orphan(sk);
+		sock_hold(sk);
+		lock_sock(sk);
+		dn_destroy_sock(sk);
+		release_sock(sk);
+		sock_put(sk);
+	}
+
+	return 0;
+}
+
+static int dn_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	struct sockaddr_dn *saddr = (struct sockaddr_dn *)uaddr;
+	struct net_device *dev, *ldev;
+	int rv;
+
+	if (addr_len != sizeof(struct sockaddr_dn))
+		return -EINVAL;
+
+	if (saddr->sdn_family != AF_DECnet)
+		return -EINVAL;
+
+	if (le16_to_cpu(saddr->sdn_nodeaddrl) && (le16_to_cpu(saddr->sdn_nodeaddrl) != 2))
+		return -EINVAL;
+
+	if (le16_to_cpu(saddr->sdn_objnamel) > DN_MAXOBJL)
+		return -EINVAL;
+
+	if (saddr->sdn_flags & ~SDF_WILD)
+		return -EINVAL;
+
+	if (!capable(CAP_NET_BIND_SERVICE) && (saddr->sdn_objnum ||
+	    (saddr->sdn_flags & SDF_WILD)))
+		return -EACCES;
+
+	if (!(saddr->sdn_flags & SDF_WILD)) {
+		if (le16_to_cpu(saddr->sdn_nodeaddrl)) {
+			rcu_read_lock();
+			ldev = NULL;
+			for_each_netdev_rcu(&init_net, dev) {
+				if (!dev->dn_ptr)
+					continue;
+				if (dn_dev_islocal(dev, dn_saddr2dn(saddr))) {
+					ldev = dev;
+					break;
+				}
+			}
+			rcu_read_unlock();
+			if (ldev == NULL)
+				return -EADDRNOTAVAIL;
+		}
+	}
+
+	rv = -EINVAL;
+	lock_sock(sk);
+	if (sock_flag(sk, SOCK_ZAPPED)) {
+		memcpy(&scp->addr, saddr, addr_len);
+		sock_reset_flag(sk, SOCK_ZAPPED);
+
+		rv = dn_hash_sock(sk);
+		if (rv)
+			sock_set_flag(sk, SOCK_ZAPPED);
+	}
+	release_sock(sk);
+
+	return rv;
+}
+
+
+static int dn_auto_bind(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	int rv;
+
+	sock_reset_flag(sk, SOCK_ZAPPED);
+
+	scp->addr.sdn_flags  = 0;
+	scp->addr.sdn_objnum = 0;
+
+	/*
+	 * This stuff is to keep compatibility with Eduardo's
+	 * patch. I hope I can dispense with it shortly...
+	 */
+	if ((scp->accessdata.acc_accl != 0) &&
+		(scp->accessdata.acc_accl <= 12)) {
+
+		scp->addr.sdn_objnamel = cpu_to_le16(scp->accessdata.acc_accl);
+		memcpy(scp->addr.sdn_objname, scp->accessdata.acc_acc, le16_to_cpu(scp->addr.sdn_objnamel));
+
+		scp->accessdata.acc_accl = 0;
+		memset(scp->accessdata.acc_acc, 0, 40);
+	}
+	/* End of compatibility stuff */
+
+	scp->addr.sdn_add.a_len = cpu_to_le16(2);
+	rv = dn_dev_bind_default((__le16 *)scp->addr.sdn_add.a_addr);
+	if (rv == 0) {
+		rv = dn_hash_sock(sk);
+		if (rv)
+			sock_set_flag(sk, SOCK_ZAPPED);
+	}
+
+	return rv;
+}
+
+static int dn_confirm_accept(struct sock *sk, long *timeo, gfp_t allocation)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	int err;
+
+	if (scp->state != DN_CR)
+		return -EINVAL;
+
+	scp->state = DN_CC;
+	scp->segsize_loc = dst_metric_advmss(__sk_dst_get(sk));
+	dn_send_conn_conf(sk, allocation);
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	for(;;) {
+		release_sock(sk);
+		if (scp->state == DN_CC)
+			*timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, *timeo);
+		lock_sock(sk);
+		err = 0;
+		if (scp->state == DN_RUN)
+			break;
+		err = sock_error(sk);
+		if (err)
+			break;
+		err = sock_intr_errno(*timeo);
+		if (signal_pending(current))
+			break;
+		err = -EAGAIN;
+		if (!*timeo)
+			break;
+	}
+	remove_wait_queue(sk_sleep(sk), &wait);
+	if (err == 0) {
+		sk->sk_socket->state = SS_CONNECTED;
+	} else if (scp->state != DN_CC) {
+		sk->sk_socket->state = SS_UNCONNECTED;
+	}
+	return err;
+}
+
+static int dn_wait_run(struct sock *sk, long *timeo)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	int err = 0;
+
+	if (scp->state == DN_RUN)
+		goto out;
+
+	if (!*timeo)
+		return -EALREADY;
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	for(;;) {
+		release_sock(sk);
+		if (scp->state == DN_CI || scp->state == DN_CC)
+			*timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, *timeo);
+		lock_sock(sk);
+		err = 0;
+		if (scp->state == DN_RUN)
+			break;
+		err = sock_error(sk);
+		if (err)
+			break;
+		err = sock_intr_errno(*timeo);
+		if (signal_pending(current))
+			break;
+		err = -ETIMEDOUT;
+		if (!*timeo)
+			break;
+	}
+	remove_wait_queue(sk_sleep(sk), &wait);
+out:
+	if (err == 0) {
+		sk->sk_socket->state = SS_CONNECTED;
+	} else if (scp->state != DN_CI && scp->state != DN_CC) {
+		sk->sk_socket->state = SS_UNCONNECTED;
+	}
+	return err;
+}
+
+static int __dn_connect(struct sock *sk, struct sockaddr_dn *addr, int addrlen, long *timeo, int flags)
+{
+	struct socket *sock = sk->sk_socket;
+	struct dn_scp *scp = DN_SK(sk);
+	int err = -EISCONN;
+	struct flowidn fld;
+	struct dst_entry *dst;
+
+	if (sock->state == SS_CONNECTED)
+		goto out;
+
+	if (sock->state == SS_CONNECTING) {
+		err = 0;
+		if (scp->state == DN_RUN) {
+			sock->state = SS_CONNECTED;
+			goto out;
+		}
+		err = -ECONNREFUSED;
+		if (scp->state != DN_CI && scp->state != DN_CC) {
+			sock->state = SS_UNCONNECTED;
+			goto out;
+		}
+		return dn_wait_run(sk, timeo);
+	}
+
+	err = -EINVAL;
+	if (scp->state != DN_O)
+		goto out;
+
+	if (addr == NULL || addrlen != sizeof(struct sockaddr_dn))
+		goto out;
+	if (addr->sdn_family != AF_DECnet)
+		goto out;
+	if (addr->sdn_flags & SDF_WILD)
+		goto out;
+
+	if (sock_flag(sk, SOCK_ZAPPED)) {
+		err = dn_auto_bind(sk->sk_socket);
+		if (err)
+			goto out;
+	}
+
+	memcpy(&scp->peer, addr, sizeof(struct sockaddr_dn));
+
+	err = -EHOSTUNREACH;
+	memset(&fld, 0, sizeof(fld));
+	fld.flowidn_oif = sk->sk_bound_dev_if;
+	fld.daddr = dn_saddr2dn(&scp->peer);
+	fld.saddr = dn_saddr2dn(&scp->addr);
+	dn_sk_ports_copy(&fld, scp);
+	fld.flowidn_proto = DNPROTO_NSP;
+	if (dn_route_output_sock(&sk->sk_dst_cache, &fld, sk, flags) < 0)
+		goto out;
+	dst = __sk_dst_get(sk);
+	sk->sk_route_caps = dst->dev->features;
+	sock->state = SS_CONNECTING;
+	scp->state = DN_CI;
+	scp->segsize_loc = dst_metric_advmss(dst);
+
+	dn_nsp_send_conninit(sk, NSP_CI);
+	err = -EINPROGRESS;
+	if (*timeo) {
+		err = dn_wait_run(sk, timeo);
+	}
+out:
+	return err;
+}
+
+static int dn_connect(struct socket *sock, struct sockaddr *uaddr, int addrlen, int flags)
+{
+	struct sockaddr_dn *addr = (struct sockaddr_dn *)uaddr;
+	struct sock *sk = sock->sk;
+	int err;
+	long timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
+
+	lock_sock(sk);
+	err = __dn_connect(sk, addr, addrlen, &timeo, 0);
+	release_sock(sk);
+
+	return err;
+}
+
+static inline int dn_check_state(struct sock *sk, struct sockaddr_dn *addr, int addrlen, long *timeo, int flags)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	switch (scp->state) {
+	case DN_RUN:
+		return 0;
+	case DN_CR:
+		return dn_confirm_accept(sk, timeo, sk->sk_allocation);
+	case DN_CI:
+	case DN_CC:
+		return dn_wait_run(sk, timeo);
+	case DN_O:
+		return __dn_connect(sk, addr, addrlen, timeo, flags);
+	}
+
+	return -EINVAL;
+}
+
+
+static void dn_access_copy(struct sk_buff *skb, struct accessdata_dn *acc)
+{
+	unsigned char *ptr = skb->data;
+
+	acc->acc_userl = *ptr++;
+	memcpy(&acc->acc_user, ptr, acc->acc_userl);
+	ptr += acc->acc_userl;
+
+	acc->acc_passl = *ptr++;
+	memcpy(&acc->acc_pass, ptr, acc->acc_passl);
+	ptr += acc->acc_passl;
+
+	acc->acc_accl = *ptr++;
+	memcpy(&acc->acc_acc, ptr, acc->acc_accl);
+
+	skb_pull(skb, acc->acc_accl + acc->acc_passl + acc->acc_userl + 3);
+
+}
+
+static void dn_user_copy(struct sk_buff *skb, struct optdata_dn *opt)
+{
+	unsigned char *ptr = skb->data;
+	u16 len = *ptr++; /* yes, it's 8bit on the wire */
+
+	BUG_ON(len > 16); /* we've checked the contents earlier */
+	opt->opt_optl   = cpu_to_le16(len);
+	opt->opt_status = 0;
+	memcpy(opt->opt_data, ptr, len);
+	skb_pull(skb, len + 1);
+}
+
+static struct sk_buff *dn_wait_for_connect(struct sock *sk, long *timeo)
+{
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	struct sk_buff *skb = NULL;
+	int err = 0;
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	for(;;) {
+		release_sock(sk);
+		skb = skb_dequeue(&sk->sk_receive_queue);
+		if (skb == NULL) {
+			*timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, *timeo);
+			skb = skb_dequeue(&sk->sk_receive_queue);
+		}
+		lock_sock(sk);
+		if (skb != NULL)
+			break;
+		err = -EINVAL;
+		if (sk->sk_state != TCP_LISTEN)
+			break;
+		err = sock_intr_errno(*timeo);
+		if (signal_pending(current))
+			break;
+		err = -EAGAIN;
+		if (!*timeo)
+			break;
+	}
+	remove_wait_queue(sk_sleep(sk), &wait);
+
+	return skb == NULL ? ERR_PTR(err) : skb;
+}
+
+static int dn_accept(struct socket *sock, struct socket *newsock, int flags,
+		     bool kern)
+{
+	struct sock *sk = sock->sk, *newsk;
+	struct sk_buff *skb = NULL;
+	struct dn_skb_cb *cb;
+	unsigned char menuver;
+	int err = 0;
+	unsigned char type;
+	long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
+	struct dst_entry *dst;
+
+	lock_sock(sk);
+
+	if (sk->sk_state != TCP_LISTEN || DN_SK(sk)->state != DN_O) {
+		release_sock(sk);
+		return -EINVAL;
+	}
+
+	skb = skb_dequeue(&sk->sk_receive_queue);
+	if (skb == NULL) {
+		skb = dn_wait_for_connect(sk, &timeo);
+		if (IS_ERR(skb)) {
+			release_sock(sk);
+			return PTR_ERR(skb);
+		}
+	}
+
+	cb = DN_SKB_CB(skb);
+	sk->sk_ack_backlog--;
+	newsk = dn_alloc_sock(sock_net(sk), newsock, sk->sk_allocation, kern);
+	if (newsk == NULL) {
+		release_sock(sk);
+		kfree_skb(skb);
+		return -ENOBUFS;
+	}
+	release_sock(sk);
+
+	dst = skb_dst(skb);
+	sk_dst_set(newsk, dst);
+	skb_dst_set(skb, NULL);
+
+	DN_SK(newsk)->state        = DN_CR;
+	DN_SK(newsk)->addrrem      = cb->src_port;
+	DN_SK(newsk)->services_rem = cb->services;
+	DN_SK(newsk)->info_rem     = cb->info;
+	DN_SK(newsk)->segsize_rem  = cb->segsize;
+	DN_SK(newsk)->accept_mode  = DN_SK(sk)->accept_mode;
+
+	if (DN_SK(newsk)->segsize_rem < 230)
+		DN_SK(newsk)->segsize_rem = 230;
+
+	if ((DN_SK(newsk)->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
+		DN_SK(newsk)->max_window = decnet_no_fc_max_cwnd;
+
+	newsk->sk_state  = TCP_LISTEN;
+	memcpy(&(DN_SK(newsk)->addr), &(DN_SK(sk)->addr), sizeof(struct sockaddr_dn));
+
+	/*
+	 * If we are listening on a wild socket, we don't want
+	 * the newly created socket on the wrong hash queue.
+	 */
+	DN_SK(newsk)->addr.sdn_flags &= ~SDF_WILD;
+
+	skb_pull(skb, dn_username2sockaddr(skb->data, skb->len, &(DN_SK(newsk)->addr), &type));
+	skb_pull(skb, dn_username2sockaddr(skb->data, skb->len, &(DN_SK(newsk)->peer), &type));
+	*(__le16 *)(DN_SK(newsk)->peer.sdn_add.a_addr) = cb->src;
+	*(__le16 *)(DN_SK(newsk)->addr.sdn_add.a_addr) = cb->dst;
+
+	menuver = *skb->data;
+	skb_pull(skb, 1);
+
+	if (menuver & DN_MENUVER_ACC)
+		dn_access_copy(skb, &(DN_SK(newsk)->accessdata));
+
+	if (menuver & DN_MENUVER_USR)
+		dn_user_copy(skb, &(DN_SK(newsk)->conndata_in));
+
+	if (menuver & DN_MENUVER_PRX)
+		DN_SK(newsk)->peer.sdn_flags |= SDF_PROXY;
+
+	if (menuver & DN_MENUVER_UIC)
+		DN_SK(newsk)->peer.sdn_flags |= SDF_UICPROXY;
+
+	kfree_skb(skb);
+
+	memcpy(&(DN_SK(newsk)->conndata_out), &(DN_SK(sk)->conndata_out),
+		sizeof(struct optdata_dn));
+	memcpy(&(DN_SK(newsk)->discdata_out), &(DN_SK(sk)->discdata_out),
+		sizeof(struct optdata_dn));
+
+	lock_sock(newsk);
+	err = dn_hash_sock(newsk);
+	if (err == 0) {
+		sock_reset_flag(newsk, SOCK_ZAPPED);
+		dn_send_conn_ack(newsk);
+
+		/*
+		 * Here we use sk->sk_allocation since although the conn conf is
+		 * for the newsk, the context is the old socket.
+		 */
+		if (DN_SK(newsk)->accept_mode == ACC_IMMED)
+			err = dn_confirm_accept(newsk, &timeo,
+						sk->sk_allocation);
+	}
+	release_sock(newsk);
+	return err;
+}
+
+
+static int dn_getname(struct socket *sock, struct sockaddr *uaddr,int peer)
+{
+	struct sockaddr_dn *sa = (struct sockaddr_dn *)uaddr;
+	struct sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+
+	lock_sock(sk);
+
+	if (peer) {
+		if ((sock->state != SS_CONNECTED &&
+		     sock->state != SS_CONNECTING) &&
+		    scp->accept_mode == ACC_IMMED) {
+			release_sock(sk);
+			return -ENOTCONN;
+		}
+
+		memcpy(sa, &scp->peer, sizeof(struct sockaddr_dn));
+	} else {
+		memcpy(sa, &scp->addr, sizeof(struct sockaddr_dn));
+	}
+
+	release_sock(sk);
+
+	return sizeof(struct sockaddr_dn);
+}
+
+
+static __poll_t dn_poll(struct file *file, struct socket *sock, poll_table  *wait)
+{
+	struct sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	__poll_t mask = datagram_poll(file, sock, wait);
+
+	if (!skb_queue_empty_lockless(&scp->other_receive_queue))
+		mask |= EPOLLRDBAND;
+
+	return mask;
+}
+
+static int dn_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	struct sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	int err = -EOPNOTSUPP;
+	long amount = 0;
+	struct sk_buff *skb;
+	int val;
+
+	switch(cmd)
+	{
+	case SIOCGIFADDR:
+	case SIOCSIFADDR:
+		return dn_dev_ioctl(cmd, (void __user *)arg);
+
+	case SIOCATMARK:
+		lock_sock(sk);
+		val = !skb_queue_empty(&scp->other_receive_queue);
+		if (scp->state != DN_RUN)
+			val = -ENOTCONN;
+		release_sock(sk);
+		return val;
+
+	case TIOCOUTQ:
+		amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
+		if (amount < 0)
+			amount = 0;
+		err = put_user(amount, (int __user *)arg);
+		break;
+
+	case TIOCINQ:
+		lock_sock(sk);
+		skb = skb_peek(&scp->other_receive_queue);
+		if (skb) {
+			amount = skb->len;
+		} else {
+			skb_queue_walk(&sk->sk_receive_queue, skb)
+				amount += skb->len;
+		}
+		release_sock(sk);
+		err = put_user(amount, (int __user *)arg);
+		break;
+
+	default:
+		err = -ENOIOCTLCMD;
+		break;
+	}
+
+	return err;
+}
+
+static int dn_listen(struct socket *sock, int backlog)
+{
+	struct sock *sk = sock->sk;
+	int err = -EINVAL;
+
+	lock_sock(sk);
+
+	if (sock_flag(sk, SOCK_ZAPPED))
+		goto out;
+
+	if ((DN_SK(sk)->state != DN_O) || (sk->sk_state == TCP_LISTEN))
+		goto out;
+
+	sk->sk_max_ack_backlog = backlog;
+	sk->sk_ack_backlog     = 0;
+	sk->sk_state           = TCP_LISTEN;
+	err                 = 0;
+	dn_rehash_sock(sk);
+
+out:
+	release_sock(sk);
+
+	return err;
+}
+
+
+static int dn_shutdown(struct socket *sock, int how)
+{
+	struct sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	int err = -ENOTCONN;
+
+	lock_sock(sk);
+
+	if (sock->state == SS_UNCONNECTED)
+		goto out;
+
+	err = 0;
+	if (sock->state == SS_DISCONNECTING)
+		goto out;
+
+	err = -EINVAL;
+	if (scp->state == DN_O)
+		goto out;
+
+	if (how != SHUT_RDWR)
+		goto out;
+
+	sk->sk_shutdown = SHUTDOWN_MASK;
+	dn_destroy_sock(sk);
+	err = 0;
+
+out:
+	release_sock(sk);
+
+	return err;
+}
+
+static int dn_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	int err;
+
+	lock_sock(sk);
+	err = __dn_setsockopt(sock, level, optname, optval, optlen, 0);
+	release_sock(sk);
+#ifdef CONFIG_NETFILTER
+	/* we need to exclude all possible ENOPROTOOPTs except default case */
+	if (err == -ENOPROTOOPT && optname != DSO_LINKINFO &&
+	    optname != DSO_STREAM && optname != DSO_SEQPACKET)
+		err = nf_setsockopt(sk, PF_DECnet, optname, optval, optlen);
+#endif
+
+	return err;
+}
+
+static int __dn_setsockopt(struct socket *sock, int level,int optname, char __user *optval, unsigned int optlen, int flags)
+{
+	struct	sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	long timeo;
+	union {
+		struct optdata_dn opt;
+		struct accessdata_dn acc;
+		int mode;
+		unsigned long win;
+		int val;
+		unsigned char services;
+		unsigned char info;
+	} u;
+	int err;
+
+	if (optlen && !optval)
+		return -EINVAL;
+
+	if (optlen > sizeof(u))
+		return -EINVAL;
+
+	if (copy_from_user(&u, optval, optlen))
+		return -EFAULT;
+
+	switch (optname) {
+	case DSO_CONDATA:
+		if (sock->state == SS_CONNECTED)
+			return -EISCONN;
+		if ((scp->state != DN_O) && (scp->state != DN_CR))
+			return -EINVAL;
+
+		if (optlen != sizeof(struct optdata_dn))
+			return -EINVAL;
+
+		if (le16_to_cpu(u.opt.opt_optl) > 16)
+			return -EINVAL;
+
+		memcpy(&scp->conndata_out, &u.opt, optlen);
+		break;
+
+	case DSO_DISDATA:
+		if (sock->state != SS_CONNECTED &&
+		    scp->accept_mode == ACC_IMMED)
+			return -ENOTCONN;
+
+		if (optlen != sizeof(struct optdata_dn))
+			return -EINVAL;
+
+		if (le16_to_cpu(u.opt.opt_optl) > 16)
+			return -EINVAL;
+
+		memcpy(&scp->discdata_out, &u.opt, optlen);
+		break;
+
+	case DSO_CONACCESS:
+		if (sock->state == SS_CONNECTED)
+			return -EISCONN;
+		if (scp->state != DN_O)
+			return -EINVAL;
+
+		if (optlen != sizeof(struct accessdata_dn))
+			return -EINVAL;
+
+		if ((u.acc.acc_accl > DN_MAXACCL) ||
+		    (u.acc.acc_passl > DN_MAXACCL) ||
+		    (u.acc.acc_userl > DN_MAXACCL))
+			return -EINVAL;
+
+		memcpy(&scp->accessdata, &u.acc, optlen);
+		break;
+
+	case DSO_ACCEPTMODE:
+		if (sock->state == SS_CONNECTED)
+			return -EISCONN;
+		if (scp->state != DN_O)
+			return -EINVAL;
+
+		if (optlen != sizeof(int))
+			return -EINVAL;
+
+		if ((u.mode != ACC_IMMED) && (u.mode != ACC_DEFER))
+			return -EINVAL;
+
+		scp->accept_mode = (unsigned char)u.mode;
+		break;
+
+	case DSO_CONACCEPT:
+		if (scp->state != DN_CR)
+			return -EINVAL;
+		timeo = sock_rcvtimeo(sk, 0);
+		err = dn_confirm_accept(sk, &timeo, sk->sk_allocation);
+		return err;
+
+	case DSO_CONREJECT:
+		if (scp->state != DN_CR)
+			return -EINVAL;
+
+		scp->state = DN_DR;
+		sk->sk_shutdown = SHUTDOWN_MASK;
+		dn_nsp_send_disc(sk, 0x38, 0, sk->sk_allocation);
+		break;
+
+	case DSO_MAXWINDOW:
+		if (optlen != sizeof(unsigned long))
+			return -EINVAL;
+		if (u.win > NSP_MAX_WINDOW)
+			u.win = NSP_MAX_WINDOW;
+		if (u.win == 0)
+			return -EINVAL;
+		scp->max_window = u.win;
+		if (scp->snd_window > u.win)
+			scp->snd_window = u.win;
+		break;
+
+	case DSO_NODELAY:
+		if (optlen != sizeof(int))
+			return -EINVAL;
+		if (scp->nonagle == TCP_NAGLE_CORK)
+			return -EINVAL;
+		scp->nonagle = (u.val == 0) ? 0 : TCP_NAGLE_OFF;
+		/* if (scp->nonagle == 1) { Push pending frames } */
+		break;
+
+	case DSO_CORK:
+		if (optlen != sizeof(int))
+			return -EINVAL;
+		if (scp->nonagle == TCP_NAGLE_OFF)
+			return -EINVAL;
+		scp->nonagle = (u.val == 0) ? 0 : TCP_NAGLE_CORK;
+		/* if (scp->nonagle == 0) { Push pending frames } */
+		break;
+
+	case DSO_SERVICES:
+		if (optlen != sizeof(unsigned char))
+			return -EINVAL;
+		if ((u.services & ~NSP_FC_MASK) != 0x01)
+			return -EINVAL;
+		if ((u.services & NSP_FC_MASK) == NSP_FC_MASK)
+			return -EINVAL;
+		scp->services_loc = u.services;
+		break;
+
+	case DSO_INFO:
+		if (optlen != sizeof(unsigned char))
+			return -EINVAL;
+		if (u.info & 0xfc)
+			return -EINVAL;
+		scp->info_loc = u.info;
+		break;
+
+	case DSO_LINKINFO:
+	case DSO_STREAM:
+	case DSO_SEQPACKET:
+	default:
+		return -ENOPROTOOPT;
+	}
+
+	return 0;
+}
+
+static int dn_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen)
+{
+	struct sock *sk = sock->sk;
+	int err;
+
+	lock_sock(sk);
+	err = __dn_getsockopt(sock, level, optname, optval, optlen, 0);
+	release_sock(sk);
+#ifdef CONFIG_NETFILTER
+	if (err == -ENOPROTOOPT && optname != DSO_STREAM &&
+	    optname != DSO_SEQPACKET && optname != DSO_CONACCEPT &&
+	    optname != DSO_CONREJECT) {
+		int len;
+
+		if (get_user(len, optlen))
+			return -EFAULT;
+
+		err = nf_getsockopt(sk, PF_DECnet, optname, optval, &len);
+		if (err >= 0)
+			err = put_user(len, optlen);
+	}
+#endif
+
+	return err;
+}
+
+static int __dn_getsockopt(struct socket *sock, int level,int optname, char __user *optval,int __user *optlen, int flags)
+{
+	struct	sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	struct linkinfo_dn link;
+	unsigned int r_len;
+	void *r_data = NULL;
+	unsigned int val;
+
+	if(get_user(r_len , optlen))
+		return -EFAULT;
+
+	switch (optname) {
+	case DSO_CONDATA:
+		if (r_len > sizeof(struct optdata_dn))
+			r_len = sizeof(struct optdata_dn);
+		r_data = &scp->conndata_in;
+		break;
+
+	case DSO_DISDATA:
+		if (r_len > sizeof(struct optdata_dn))
+			r_len = sizeof(struct optdata_dn);
+		r_data = &scp->discdata_in;
+		break;
+
+	case DSO_CONACCESS:
+		if (r_len > sizeof(struct accessdata_dn))
+			r_len = sizeof(struct accessdata_dn);
+		r_data = &scp->accessdata;
+		break;
+
+	case DSO_ACCEPTMODE:
+		if (r_len > sizeof(unsigned char))
+			r_len = sizeof(unsigned char);
+		r_data = &scp->accept_mode;
+		break;
+
+	case DSO_LINKINFO:
+		if (r_len > sizeof(struct linkinfo_dn))
+			r_len = sizeof(struct linkinfo_dn);
+
+		memset(&link, 0, sizeof(link));
+
+		switch (sock->state) {
+		case SS_CONNECTING:
+			link.idn_linkstate = LL_CONNECTING;
+			break;
+		case SS_DISCONNECTING:
+			link.idn_linkstate = LL_DISCONNECTING;
+			break;
+		case SS_CONNECTED:
+			link.idn_linkstate = LL_RUNNING;
+			break;
+		default:
+			link.idn_linkstate = LL_INACTIVE;
+		}
+
+		link.idn_segsize = scp->segsize_rem;
+		r_data = &link;
+		break;
+
+	case DSO_MAXWINDOW:
+		if (r_len > sizeof(unsigned long))
+			r_len = sizeof(unsigned long);
+		r_data = &scp->max_window;
+		break;
+
+	case DSO_NODELAY:
+		if (r_len > sizeof(int))
+			r_len = sizeof(int);
+		val = (scp->nonagle == TCP_NAGLE_OFF);
+		r_data = &val;
+		break;
+
+	case DSO_CORK:
+		if (r_len > sizeof(int))
+			r_len = sizeof(int);
+		val = (scp->nonagle == TCP_NAGLE_CORK);
+		r_data = &val;
+		break;
+
+	case DSO_SERVICES:
+		if (r_len > sizeof(unsigned char))
+			r_len = sizeof(unsigned char);
+		r_data = &scp->services_rem;
+		break;
+
+	case DSO_INFO:
+		if (r_len > sizeof(unsigned char))
+			r_len = sizeof(unsigned char);
+		r_data = &scp->info_rem;
+		break;
+
+	case DSO_STREAM:
+	case DSO_SEQPACKET:
+	case DSO_CONACCEPT:
+	case DSO_CONREJECT:
+	default:
+		return -ENOPROTOOPT;
+	}
+
+	if (r_data) {
+		if (copy_to_user(optval, r_data, r_len))
+			return -EFAULT;
+		if (put_user(r_len, optlen))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+
+static int dn_data_ready(struct sock *sk, struct sk_buff_head *q, int flags, int target)
+{
+	struct sk_buff *skb;
+	int len = 0;
+
+	if (flags & MSG_OOB)
+		return !skb_queue_empty(q) ? 1 : 0;
+
+	skb_queue_walk(q, skb) {
+		struct dn_skb_cb *cb = DN_SKB_CB(skb);
+		len += skb->len;
+
+		if (cb->nsp_flags & 0x40) {
+			/* SOCK_SEQPACKET reads to EOM */
+			if (sk->sk_type == SOCK_SEQPACKET)
+				return 1;
+			/* so does SOCK_STREAM unless WAITALL is specified */
+			if (!(flags & MSG_WAITALL))
+				return 1;
+		}
+
+		/* minimum data length for read exceeded */
+		if (len >= target)
+			return 1;
+	}
+
+	return 0;
+}
+
+
+static int dn_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
+		      int flags)
+{
+	struct sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	struct sk_buff_head *queue = &sk->sk_receive_queue;
+	size_t target = size > 1 ? 1 : 0;
+	size_t copied = 0;
+	int rv = 0;
+	struct sk_buff *skb, *n;
+	struct dn_skb_cb *cb = NULL;
+	unsigned char eor = 0;
+	long timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+
+	lock_sock(sk);
+
+	if (sock_flag(sk, SOCK_ZAPPED)) {
+		rv = -EADDRNOTAVAIL;
+		goto out;
+	}
+
+	if (sk->sk_shutdown & RCV_SHUTDOWN) {
+		rv = 0;
+		goto out;
+	}
+
+	rv = dn_check_state(sk, NULL, 0, &timeo, flags);
+	if (rv)
+		goto out;
+
+	if (flags & ~(MSG_CMSG_COMPAT|MSG_PEEK|MSG_OOB|MSG_WAITALL|MSG_DONTWAIT|MSG_NOSIGNAL)) {
+		rv = -EOPNOTSUPP;
+		goto out;
+	}
+
+	if (flags & MSG_OOB)
+		queue = &scp->other_receive_queue;
+
+	if (flags & MSG_WAITALL)
+		target = size;
+
+
+	/*
+	 * See if there is data ready to read, sleep if there isn't
+	 */
+	for(;;) {
+		DEFINE_WAIT_FUNC(wait, woken_wake_function);
+
+		if (sk->sk_err)
+			goto out;
+
+		if (!skb_queue_empty(&scp->other_receive_queue)) {
+			if (!(flags & MSG_OOB)) {
+				msg->msg_flags |= MSG_OOB;
+				if (!scp->other_report) {
+					scp->other_report = 1;
+					goto out;
+				}
+			}
+		}
+
+		if (scp->state != DN_RUN)
+			goto out;
+
+		if (signal_pending(current)) {
+			rv = sock_intr_errno(timeo);
+			goto out;
+		}
+
+		if (dn_data_ready(sk, queue, flags, target))
+			break;
+
+		if (flags & MSG_DONTWAIT) {
+			rv = -EWOULDBLOCK;
+			goto out;
+		}
+
+		add_wait_queue(sk_sleep(sk), &wait);
+		sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+		sk_wait_event(sk, &timeo, dn_data_ready(sk, queue, flags, target), &wait);
+		sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+		remove_wait_queue(sk_sleep(sk), &wait);
+	}
+
+	skb_queue_walk_safe(queue, skb, n) {
+		unsigned int chunk = skb->len;
+		cb = DN_SKB_CB(skb);
+
+		if ((chunk + copied) > size)
+			chunk = size - copied;
+
+		if (memcpy_to_msg(msg, skb->data, chunk)) {
+			rv = -EFAULT;
+			break;
+		}
+		copied += chunk;
+
+		if (!(flags & MSG_PEEK))
+			skb_pull(skb, chunk);
+
+		eor = cb->nsp_flags & 0x40;
+
+		if (skb->len == 0) {
+			skb_unlink(skb, queue);
+			kfree_skb(skb);
+			/*
+			 * N.B. Don't refer to skb or cb after this point
+			 * in loop.
+			 */
+			if ((scp->flowloc_sw == DN_DONTSEND) && !dn_congested(sk)) {
+				scp->flowloc_sw = DN_SEND;
+				dn_nsp_send_link(sk, DN_SEND, 0);
+			}
+		}
+
+		if (eor) {
+			if (sk->sk_type == SOCK_SEQPACKET)
+				break;
+			if (!(flags & MSG_WAITALL))
+				break;
+		}
+
+		if (flags & MSG_OOB)
+			break;
+
+		if (copied >= target)
+			break;
+	}
+
+	rv = copied;
+
+
+	if (eor && (sk->sk_type == SOCK_SEQPACKET))
+		msg->msg_flags |= MSG_EOR;
+
+out:
+	if (rv == 0)
+		rv = (flags & MSG_PEEK) ? -sk->sk_err : sock_error(sk);
+
+	if ((rv >= 0) && msg->msg_name) {
+		__sockaddr_check_size(sizeof(struct sockaddr_dn));
+		memcpy(msg->msg_name, &scp->peer, sizeof(struct sockaddr_dn));
+		msg->msg_namelen = sizeof(struct sockaddr_dn);
+	}
+
+	release_sock(sk);
+
+	return rv;
+}
+
+
+static inline int dn_queue_too_long(struct dn_scp *scp, struct sk_buff_head *queue, int flags)
+{
+	unsigned char fctype = scp->services_rem & NSP_FC_MASK;
+	if (skb_queue_len(queue) >= scp->snd_window)
+		return 1;
+	if (fctype != NSP_FC_NONE) {
+		if (flags & MSG_OOB) {
+			if (scp->flowrem_oth == 0)
+				return 1;
+		} else {
+			if (scp->flowrem_dat == 0)
+				return 1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * The DECnet spec requires that the "routing layer" accepts packets which
+ * are at least 230 bytes in size. This excludes any headers which the NSP
+ * layer might add, so we always assume that we'll be using the maximal
+ * length header on data packets. The variation in length is due to the
+ * inclusion (or not) of the two 16 bit acknowledgement fields so it doesn't
+ * make much practical difference.
+ */
+unsigned int dn_mss_from_pmtu(struct net_device *dev, int mtu)
+{
+	unsigned int mss = 230 - DN_MAX_NSP_DATA_HEADER;
+	if (dev) {
+		struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
+		mtu -= LL_RESERVED_SPACE(dev);
+		if (dn_db->use_long)
+			mtu -= 21;
+		else
+			mtu -= 6;
+		mtu -= DN_MAX_NSP_DATA_HEADER;
+	} else {
+		/*
+		 * 21 = long header, 16 = guess at MAC header length
+		 */
+		mtu -= (21 + DN_MAX_NSP_DATA_HEADER + 16);
+	}
+	if (mtu > mss)
+		mss = mtu;
+	return mss;
+}
+
+static inline unsigned int dn_current_mss(struct sock *sk, int flags)
+{
+	struct dst_entry *dst = __sk_dst_get(sk);
+	struct dn_scp *scp = DN_SK(sk);
+	int mss_now = min_t(int, scp->segsize_loc, scp->segsize_rem);
+
+	/* Other data messages are limited to 16 bytes per packet */
+	if (flags & MSG_OOB)
+		return 16;
+
+	/* This works out the maximum size of segment we can send out */
+	if (dst) {
+		u32 mtu = dst_mtu(dst);
+		mss_now = min_t(int, dn_mss_from_pmtu(dst->dev, mtu), mss_now);
+	}
+
+	return mss_now;
+}
+
+/*
+ * N.B. We get the timeout wrong here, but then we always did get it
+ * wrong before and this is another step along the road to correcting
+ * it. It ought to get updated each time we pass through the routine,
+ * but in practise it probably doesn't matter too much for now.
+ */
+static inline struct sk_buff *dn_alloc_send_pskb(struct sock *sk,
+			      unsigned long datalen, int noblock,
+			      int *errcode)
+{
+	struct sk_buff *skb = sock_alloc_send_skb(sk, datalen,
+						   noblock, errcode);
+	if (skb) {
+		skb->protocol = htons(ETH_P_DNA_RT);
+		skb->pkt_type = PACKET_OUTGOING;
+	}
+	return skb;
+}
+
+static int dn_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
+{
+	struct sock *sk = sock->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	size_t mss;
+	struct sk_buff_head *queue = &scp->data_xmit_queue;
+	int flags = msg->msg_flags;
+	int err = 0;
+	size_t sent = 0;
+	int addr_len = msg->msg_namelen;
+	DECLARE_SOCKADDR(struct sockaddr_dn *, addr, msg->msg_name);
+	struct sk_buff *skb = NULL;
+	struct dn_skb_cb *cb;
+	size_t len;
+	unsigned char fctype;
+	long timeo;
+
+	if (flags & ~(MSG_TRYHARD|MSG_OOB|MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|MSG_MORE|MSG_CMSG_COMPAT))
+		return -EOPNOTSUPP;
+
+	if (addr_len && (addr_len != sizeof(struct sockaddr_dn)))
+		return -EINVAL;
+
+	lock_sock(sk);
+	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+	/*
+	 * The only difference between stream sockets and sequenced packet
+	 * sockets is that the stream sockets always behave as if MSG_EOR
+	 * has been set.
+	 */
+	if (sock->type == SOCK_STREAM) {
+		if (flags & MSG_EOR) {
+			err = -EINVAL;
+			goto out;
+		}
+		flags |= MSG_EOR;
+	}
+
+
+	err = dn_check_state(sk, addr, addr_len, &timeo, flags);
+	if (err)
+		goto out_err;
+
+	if (sk->sk_shutdown & SEND_SHUTDOWN) {
+		err = -EPIPE;
+		if (!(flags & MSG_NOSIGNAL))
+			send_sig(SIGPIPE, current, 0);
+		goto out_err;
+	}
+
+	if ((flags & MSG_TRYHARD) && sk->sk_dst_cache)
+		dst_negative_advice(sk);
+
+	mss = scp->segsize_rem;
+	fctype = scp->services_rem & NSP_FC_MASK;
+
+	mss = dn_current_mss(sk, flags);
+
+	if (flags & MSG_OOB) {
+		queue = &scp->other_xmit_queue;
+		if (size > mss) {
+			err = -EMSGSIZE;
+			goto out;
+		}
+	}
+
+	scp->persist_fxn = dn_nsp_xmit_timeout;
+
+	while(sent < size) {
+		err = sock_error(sk);
+		if (err)
+			goto out;
+
+		if (signal_pending(current)) {
+			err = sock_intr_errno(timeo);
+			goto out;
+		}
+
+		/*
+		 * Calculate size that we wish to send.
+		 */
+		len = size - sent;
+
+		if (len > mss)
+			len = mss;
+
+		/*
+		 * Wait for queue size to go down below the window
+		 * size.
+		 */
+		if (dn_queue_too_long(scp, queue, flags)) {
+			DEFINE_WAIT_FUNC(wait, woken_wake_function);
+
+			if (flags & MSG_DONTWAIT) {
+				err = -EWOULDBLOCK;
+				goto out;
+			}
+
+			add_wait_queue(sk_sleep(sk), &wait);
+			sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+			sk_wait_event(sk, &timeo,
+				      !dn_queue_too_long(scp, queue, flags), &wait);
+			sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+			remove_wait_queue(sk_sleep(sk), &wait);
+			continue;
+		}
+
+		/*
+		 * Get a suitably sized skb.
+		 * 64 is a bit of a hack really, but its larger than any
+		 * link-layer headers and has served us well as a good
+		 * guess as to their real length.
+		 */
+		skb = dn_alloc_send_pskb(sk, len + 64 + DN_MAX_NSP_DATA_HEADER,
+					 flags & MSG_DONTWAIT, &err);
+
+		if (err)
+			break;
+
+		if (!skb)
+			continue;
+
+		cb = DN_SKB_CB(skb);
+
+		skb_reserve(skb, 64 + DN_MAX_NSP_DATA_HEADER);
+
+		if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
+			err = -EFAULT;
+			goto out;
+		}
+
+		if (flags & MSG_OOB) {
+			cb->nsp_flags = 0x30;
+			if (fctype != NSP_FC_NONE)
+				scp->flowrem_oth--;
+		} else {
+			cb->nsp_flags = 0x00;
+			if (scp->seg_total == 0)
+				cb->nsp_flags |= 0x20;
+
+			scp->seg_total += len;
+
+			if (((sent + len) == size) && (flags & MSG_EOR)) {
+				cb->nsp_flags |= 0x40;
+				scp->seg_total = 0;
+				if (fctype == NSP_FC_SCMC)
+					scp->flowrem_dat--;
+			}
+			if (fctype == NSP_FC_SRC)
+				scp->flowrem_dat--;
+		}
+
+		sent += len;
+		dn_nsp_queue_xmit(sk, skb, sk->sk_allocation, flags & MSG_OOB);
+		skb = NULL;
+
+		scp->persist = dn_nsp_persist(sk);
+
+	}
+out:
+
+	kfree_skb(skb);
+
+	release_sock(sk);
+
+	return sent ? sent : err;
+
+out_err:
+	err = sk_stream_error(sk, flags, err);
+	release_sock(sk);
+	return err;
+}
+
+static int dn_device_event(struct notifier_block *this, unsigned long event,
+			   void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	if (!net_eq(dev_net(dev), &init_net))
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UP:
+		dn_dev_up(dev);
+		break;
+	case NETDEV_DOWN:
+		dn_dev_down(dev);
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block dn_dev_notifier = {
+	.notifier_call = dn_device_event,
+};
+
+static struct packet_type dn_dix_packet_type __read_mostly = {
+	.type =		cpu_to_be16(ETH_P_DNA_RT),
+	.func =		dn_route_rcv,
+};
+
+#ifdef CONFIG_PROC_FS
+struct dn_iter_state {
+	int bucket;
+};
+
+static struct sock *dn_socket_get_first(struct seq_file *seq)
+{
+	struct dn_iter_state *state = seq->private;
+	struct sock *n = NULL;
+
+	for(state->bucket = 0;
+	    state->bucket < DN_SK_HASH_SIZE;
+	    ++state->bucket) {
+		n = sk_head(&dn_sk_hash[state->bucket]);
+		if (n)
+			break;
+	}
+
+	return n;
+}
+
+static struct sock *dn_socket_get_next(struct seq_file *seq,
+				       struct sock *n)
+{
+	struct dn_iter_state *state = seq->private;
+
+	n = sk_next(n);
+try_again:
+	if (n)
+		goto out;
+	if (++state->bucket >= DN_SK_HASH_SIZE)
+		goto out;
+	n = sk_head(&dn_sk_hash[state->bucket]);
+	goto try_again;
+out:
+	return n;
+}
+
+static struct sock *socket_get_idx(struct seq_file *seq, loff_t *pos)
+{
+	struct sock *sk = dn_socket_get_first(seq);
+
+	if (sk) {
+		while(*pos && (sk = dn_socket_get_next(seq, sk)))
+			--*pos;
+	}
+	return *pos ? NULL : sk;
+}
+
+static void *dn_socket_get_idx(struct seq_file *seq, loff_t pos)
+{
+	void *rc;
+	read_lock_bh(&dn_hash_lock);
+	rc = socket_get_idx(seq, &pos);
+	if (!rc) {
+		read_unlock_bh(&dn_hash_lock);
+	}
+	return rc;
+}
+
+static void *dn_socket_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	return *pos ? dn_socket_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
+}
+
+static void *dn_socket_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	void *rc;
+
+	if (v == SEQ_START_TOKEN) {
+		rc = dn_socket_get_idx(seq, 0);
+		goto out;
+	}
+
+	rc = dn_socket_get_next(seq, v);
+	if (rc)
+		goto out;
+	read_unlock_bh(&dn_hash_lock);
+out:
+	++*pos;
+	return rc;
+}
+
+static void dn_socket_seq_stop(struct seq_file *seq, void *v)
+{
+	if (v && v != SEQ_START_TOKEN)
+		read_unlock_bh(&dn_hash_lock);
+}
+
+#define IS_NOT_PRINTABLE(x) ((x) < 32 || (x) > 126)
+
+static void dn_printable_object(struct sockaddr_dn *dn, unsigned char *buf)
+{
+	int i;
+
+	switch (le16_to_cpu(dn->sdn_objnamel)) {
+	case 0:
+		sprintf(buf, "%d", dn->sdn_objnum);
+		break;
+	default:
+		for (i = 0; i < le16_to_cpu(dn->sdn_objnamel); i++) {
+			buf[i] = dn->sdn_objname[i];
+			if (IS_NOT_PRINTABLE(buf[i]))
+				buf[i] = '.';
+		}
+		buf[i] = 0;
+	}
+}
+
+static char *dn_state2asc(unsigned char state)
+{
+	switch (state) {
+	case DN_O:
+		return "OPEN";
+	case DN_CR:
+		return "  CR";
+	case DN_DR:
+		return "  DR";
+	case DN_DRC:
+		return " DRC";
+	case DN_CC:
+		return "  CC";
+	case DN_CI:
+		return "  CI";
+	case DN_NR:
+		return "  NR";
+	case DN_NC:
+		return "  NC";
+	case DN_CD:
+		return "  CD";
+	case DN_RJ:
+		return "  RJ";
+	case DN_RUN:
+		return " RUN";
+	case DN_DI:
+		return "  DI";
+	case DN_DIC:
+		return " DIC";
+	case DN_DN:
+		return "  DN";
+	case DN_CL:
+		return "  CL";
+	case DN_CN:
+		return "  CN";
+	}
+
+	return "????";
+}
+
+static inline void dn_socket_format_entry(struct seq_file *seq, struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	char buf1[DN_ASCBUF_LEN];
+	char buf2[DN_ASCBUF_LEN];
+	char local_object[DN_MAXOBJL+3];
+	char remote_object[DN_MAXOBJL+3];
+
+	dn_printable_object(&scp->addr, local_object);
+	dn_printable_object(&scp->peer, remote_object);
+
+	seq_printf(seq,
+		   "%6s/%04X %04d:%04d %04d:%04d %01d %-16s "
+		   "%6s/%04X %04d:%04d %04d:%04d %01d %-16s %4s %s\n",
+		   dn_addr2asc(le16_to_cpu(dn_saddr2dn(&scp->addr)), buf1),
+		   scp->addrloc,
+		   scp->numdat,
+		   scp->numoth,
+		   scp->ackxmt_dat,
+		   scp->ackxmt_oth,
+		   scp->flowloc_sw,
+		   local_object,
+		   dn_addr2asc(le16_to_cpu(dn_saddr2dn(&scp->peer)), buf2),
+		   scp->addrrem,
+		   scp->numdat_rcv,
+		   scp->numoth_rcv,
+		   scp->ackrcv_dat,
+		   scp->ackrcv_oth,
+		   scp->flowrem_sw,
+		   remote_object,
+		   dn_state2asc(scp->state),
+		   ((scp->accept_mode == ACC_IMMED) ? "IMMED" : "DEFER"));
+}
+
+static int dn_socket_seq_show(struct seq_file *seq, void *v)
+{
+	if (v == SEQ_START_TOKEN) {
+		seq_puts(seq, "Local                                              Remote\n");
+	} else {
+		dn_socket_format_entry(seq, v);
+	}
+	return 0;
+}
+
+static const struct seq_operations dn_socket_seq_ops = {
+	.start	= dn_socket_seq_start,
+	.next	= dn_socket_seq_next,
+	.stop	= dn_socket_seq_stop,
+	.show	= dn_socket_seq_show,
+};
+#endif
+
+static const struct net_proto_family	dn_family_ops = {
+	.family =	AF_DECnet,
+	.create =	dn_create,
+	.owner	=	THIS_MODULE,
+};
+
+static const struct proto_ops dn_proto_ops = {
+	.family =	AF_DECnet,
+	.owner =	THIS_MODULE,
+	.release =	dn_release,
+	.bind =		dn_bind,
+	.connect =	dn_connect,
+	.socketpair =	sock_no_socketpair,
+	.accept =	dn_accept,
+	.getname =	dn_getname,
+	.poll =		dn_poll,
+	.ioctl =	dn_ioctl,
+	.listen =	dn_listen,
+	.shutdown =	dn_shutdown,
+	.setsockopt =	dn_setsockopt,
+	.getsockopt =	dn_getsockopt,
+	.sendmsg =	dn_sendmsg,
+	.recvmsg =	dn_recvmsg,
+	.mmap =		sock_no_mmap,
+	.sendpage =	sock_no_sendpage,
+};
+
+MODULE_DESCRIPTION("The Linux DECnet Network Protocol");
+MODULE_AUTHOR("Linux DECnet Project Team");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETPROTO(PF_DECnet);
+
+static const char banner[] __initconst = KERN_INFO
+"NET4: DECnet for Linux: V.2.5.68s (C) 1995-2003 Linux DECnet Project Team\n";
+
+static int __init decnet_init(void)
+{
+	int rc;
+
+	printk(banner);
+
+	rc = proto_register(&dn_proto, 1);
+	if (rc != 0)
+		goto out;
+
+	dn_neigh_init();
+	dn_dev_init();
+	dn_route_init();
+	dn_fib_init();
+
+	sock_register(&dn_family_ops);
+	dev_add_pack(&dn_dix_packet_type);
+	register_netdevice_notifier(&dn_dev_notifier);
+
+	proc_create_seq_private("decnet", 0444, init_net.proc_net,
+			&dn_socket_seq_ops, sizeof(struct dn_iter_state),
+			NULL);
+	dn_register_sysctl();
+out:
+	return rc;
+
+}
+module_init(decnet_init);
+
+/*
+ * Prevent DECnet module unloading until its fixed properly.
+ * Requires an audit of the code to check for memory leaks and
+ * initialisation problems etc.
+ */
+#if 0
+static void __exit decnet_exit(void)
+{
+	sock_unregister(AF_DECnet);
+	rtnl_unregister_all(PF_DECnet);
+	dev_remove_pack(&dn_dix_packet_type);
+
+	dn_unregister_sysctl();
+
+	unregister_netdevice_notifier(&dn_dev_notifier);
+
+	dn_route_cleanup();
+	dn_dev_cleanup();
+	dn_neigh_cleanup();
+	dn_fib_cleanup();
+
+	remove_proc_entry("decnet", init_net.proc_net);
+
+	proto_unregister(&dn_proto);
+
+	rcu_barrier_bh(); /* Wait for completion of call_rcu_bh()'s */
+}
+module_exit(decnet_exit);
+#endif
diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
new file mode 100644
index 000000000..3235540f6
--- /dev/null
+++ b/net/decnet/dn_dev.c
@@ -0,0 +1,1438 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Device Layer
+ *
+ * Authors:     Steve Whitehouse <SteveW@ACM.org>
+ *              Eduardo Marcelo Serrat <emserrat@geocities.com>
+ *
+ * Changes:
+ *          Steve Whitehouse : Devices now see incoming frames so they
+ *                             can mark on who it came from.
+ *          Steve Whitehouse : Fixed bug in creating neighbours. Each neighbour
+ *                             can now have a device specific setup func.
+ *          Steve Whitehouse : Added /proc/sys/net/decnet/conf/<dev>/
+ *          Steve Whitehouse : Fixed bug which sometimes killed timer
+ *          Steve Whitehouse : Multiple ifaddr support
+ *          Steve Whitehouse : SIOCGIFCONF is now a compile time option
+ *          Steve Whitehouse : /proc/sys/net/decnet/conf/<sys>/forwarding
+ *          Steve Whitehouse : Removed timer1 - it's a user space issue now
+ *         Patrick Caulfield : Fixed router hello message format
+ *          Steve Whitehouse : Got rid of constant sizes for blksize for
+ *                             devices. All mtu based now.
+ */
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/if_addr.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/skbuff.h>
+#include <linux/sysctl.h>
+#include <linux/notifier.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/uaccess.h>
+#include <net/net_namespace.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/flow.h>
+#include <net/fib_rules.h>
+#include <net/netlink.h>
+#include <net/dn.h>
+#include <net/dn_dev.h>
+#include <net/dn_route.h>
+#include <net/dn_neigh.h>
+#include <net/dn_fib.h>
+
+#define DN_IFREQ_SIZE (offsetof(struct ifreq, ifr_ifru) + sizeof(struct sockaddr_dn))
+
+static char dn_rt_all_end_mcast[ETH_ALEN] = {0xAB,0x00,0x00,0x04,0x00,0x00};
+static char dn_rt_all_rt_mcast[ETH_ALEN]  = {0xAB,0x00,0x00,0x03,0x00,0x00};
+static char dn_hiord[ETH_ALEN]            = {0xAA,0x00,0x04,0x00,0x00,0x00};
+static unsigned char dn_eco_version[3]    = {0x02,0x00,0x00};
+
+extern struct neigh_table dn_neigh_table;
+
+/*
+ * decnet_address is kept in network order.
+ */
+__le16 decnet_address = 0;
+
+static DEFINE_SPINLOCK(dndev_lock);
+static struct net_device *decnet_default_device;
+static BLOCKING_NOTIFIER_HEAD(dnaddr_chain);
+
+static struct dn_dev *dn_dev_create(struct net_device *dev, int *err);
+static void dn_dev_delete(struct net_device *dev);
+static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa);
+
+static int dn_eth_up(struct net_device *);
+static void dn_eth_down(struct net_device *);
+static void dn_send_brd_hello(struct net_device *dev, struct dn_ifaddr *ifa);
+static void dn_send_ptp_hello(struct net_device *dev, struct dn_ifaddr *ifa);
+
+static struct dn_dev_parms dn_dev_list[] =  {
+{
+	.type =		ARPHRD_ETHER, /* Ethernet */
+	.mode =		DN_DEV_BCAST,
+	.state =	DN_DEV_S_RU,
+	.t2 =		1,
+	.t3 =		10,
+	.name =		"ethernet",
+	.up =		dn_eth_up,
+	.down = 	dn_eth_down,
+	.timer3 =	dn_send_brd_hello,
+},
+{
+	.type =		ARPHRD_IPGRE, /* DECnet tunneled over GRE in IP */
+	.mode =		DN_DEV_BCAST,
+	.state =	DN_DEV_S_RU,
+	.t2 =		1,
+	.t3 =		10,
+	.name =		"ipgre",
+	.timer3 =	dn_send_brd_hello,
+},
+#if 0
+{
+	.type =		ARPHRD_X25, /* Bog standard X.25 */
+	.mode =		DN_DEV_UCAST,
+	.state =	DN_DEV_S_DS,
+	.t2 =		1,
+	.t3 =		120,
+	.name =		"x25",
+	.timer3 =	dn_send_ptp_hello,
+},
+#endif
+#if 0
+{
+	.type =		ARPHRD_PPP, /* DECnet over PPP */
+	.mode =		DN_DEV_BCAST,
+	.state =	DN_DEV_S_RU,
+	.t2 =		1,
+	.t3 =		10,
+	.name =		"ppp",
+	.timer3 =	dn_send_brd_hello,
+},
+#endif
+{
+	.type =		ARPHRD_DDCMP, /* DECnet over DDCMP */
+	.mode =		DN_DEV_UCAST,
+	.state =	DN_DEV_S_DS,
+	.t2 =		1,
+	.t3 =		120,
+	.name =		"ddcmp",
+	.timer3 =	dn_send_ptp_hello,
+},
+{
+	.type =		ARPHRD_LOOPBACK, /* Loopback interface - always last */
+	.mode =		DN_DEV_BCAST,
+	.state =	DN_DEV_S_RU,
+	.t2 =		1,
+	.t3 =		10,
+	.name =		"loopback",
+	.timer3 =	dn_send_brd_hello,
+}
+};
+
+#define DN_DEV_LIST_SIZE ARRAY_SIZE(dn_dev_list)
+
+#define DN_DEV_PARMS_OFFSET(x) offsetof(struct dn_dev_parms, x)
+
+#ifdef CONFIG_SYSCTL
+
+static int min_t2[] = { 1 };
+static int max_t2[] = { 60 }; /* No max specified, but this seems sensible */
+static int min_t3[] = { 1 };
+static int max_t3[] = { 8191 }; /* Must fit in 16 bits when multiplied by BCT3MULT or T3MULT */
+
+static int min_priority[1];
+static int max_priority[] = { 127 }; /* From DECnet spec */
+
+static int dn_forwarding_proc(struct ctl_table *, int,
+			void __user *, size_t *, loff_t *);
+static struct dn_dev_sysctl_table {
+	struct ctl_table_header *sysctl_header;
+	struct ctl_table dn_dev_vars[5];
+} dn_dev_sysctl = {
+	NULL,
+	{
+	{
+		.procname = "forwarding",
+		.data = (void *)DN_DEV_PARMS_OFFSET(forwarding),
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = dn_forwarding_proc,
+	},
+	{
+		.procname = "priority",
+		.data = (void *)DN_DEV_PARMS_OFFSET(priority),
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_priority,
+		.extra2 = &max_priority
+	},
+	{
+		.procname = "t2",
+		.data = (void *)DN_DEV_PARMS_OFFSET(t2),
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_t2,
+		.extra2 = &max_t2
+	},
+	{
+		.procname = "t3",
+		.data = (void *)DN_DEV_PARMS_OFFSET(t3),
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_t3,
+		.extra2 = &max_t3
+	},
+	{ }
+	},
+};
+
+static void dn_dev_sysctl_register(struct net_device *dev, struct dn_dev_parms *parms)
+{
+	struct dn_dev_sysctl_table *t;
+	int i;
+
+	char path[sizeof("net/decnet/conf/") + IFNAMSIZ];
+
+	t = kmemdup(&dn_dev_sysctl, sizeof(*t), GFP_KERNEL);
+	if (t == NULL)
+		return;
+
+	for(i = 0; i < ARRAY_SIZE(t->dn_dev_vars) - 1; i++) {
+		long offset = (long)t->dn_dev_vars[i].data;
+		t->dn_dev_vars[i].data = ((char *)parms) + offset;
+	}
+
+	snprintf(path, sizeof(path), "net/decnet/conf/%s",
+		dev? dev->name : parms->name);
+
+	t->dn_dev_vars[0].extra1 = (void *)dev;
+
+	t->sysctl_header = register_net_sysctl(&init_net, path, t->dn_dev_vars);
+	if (t->sysctl_header == NULL)
+		kfree(t);
+	else
+		parms->sysctl = t;
+}
+
+static void dn_dev_sysctl_unregister(struct dn_dev_parms *parms)
+{
+	if (parms->sysctl) {
+		struct dn_dev_sysctl_table *t = parms->sysctl;
+		parms->sysctl = NULL;
+		unregister_net_sysctl_table(t->sysctl_header);
+		kfree(t);
+	}
+}
+
+static int dn_forwarding_proc(struct ctl_table *table, int write,
+				void __user *buffer,
+				size_t *lenp, loff_t *ppos)
+{
+#ifdef CONFIG_DECNET_ROUTER
+	struct net_device *dev = table->extra1;
+	struct dn_dev *dn_db;
+	int err;
+	int tmp, old;
+
+	if (table->extra1 == NULL)
+		return -EINVAL;
+
+	dn_db = rcu_dereference_raw(dev->dn_ptr);
+	old = dn_db->parms.forwarding;
+
+	err = proc_dointvec(table, write, buffer, lenp, ppos);
+
+	if ((err >= 0) && write) {
+		if (dn_db->parms.forwarding < 0)
+			dn_db->parms.forwarding = 0;
+		if (dn_db->parms.forwarding > 2)
+			dn_db->parms.forwarding = 2;
+		/*
+		 * What an ugly hack this is... its works, just. It
+		 * would be nice if sysctl/proc were just that little
+		 * bit more flexible so I don't have to write a special
+		 * routine, or suffer hacks like this - SJW
+		 */
+		tmp = dn_db->parms.forwarding;
+		dn_db->parms.forwarding = old;
+		if (dn_db->parms.down)
+			dn_db->parms.down(dev);
+		dn_db->parms.forwarding = tmp;
+		if (dn_db->parms.up)
+			dn_db->parms.up(dev);
+	}
+
+	return err;
+#else
+	return -EINVAL;
+#endif
+}
+
+#else /* CONFIG_SYSCTL */
+static void dn_dev_sysctl_unregister(struct dn_dev_parms *parms)
+{
+}
+static void dn_dev_sysctl_register(struct net_device *dev, struct dn_dev_parms *parms)
+{
+}
+
+#endif /* CONFIG_SYSCTL */
+
+static inline __u16 mtu2blksize(struct net_device *dev)
+{
+	u32 blksize = dev->mtu;
+	if (blksize > 0xffff)
+		blksize = 0xffff;
+
+	if (dev->type == ARPHRD_ETHER ||
+	    dev->type == ARPHRD_PPP ||
+	    dev->type == ARPHRD_IPGRE ||
+	    dev->type == ARPHRD_LOOPBACK)
+		blksize -= 2;
+
+	return (__u16)blksize;
+}
+
+static struct dn_ifaddr *dn_dev_alloc_ifa(void)
+{
+	struct dn_ifaddr *ifa;
+
+	ifa = kzalloc(sizeof(*ifa), GFP_KERNEL);
+
+	return ifa;
+}
+
+static void dn_dev_free_ifa(struct dn_ifaddr *ifa)
+{
+	kfree_rcu(ifa, rcu);
+}
+
+static void dn_dev_del_ifa(struct dn_dev *dn_db, struct dn_ifaddr __rcu **ifap, int destroy)
+{
+	struct dn_ifaddr *ifa1 = rtnl_dereference(*ifap);
+	unsigned char mac_addr[6];
+	struct net_device *dev = dn_db->dev;
+
+	ASSERT_RTNL();
+
+	*ifap = ifa1->ifa_next;
+
+	if (dn_db->dev->type == ARPHRD_ETHER) {
+		if (ifa1->ifa_local != dn_eth2dn(dev->dev_addr)) {
+			dn_dn2eth(mac_addr, ifa1->ifa_local);
+			dev_mc_del(dev, mac_addr);
+		}
+	}
+
+	dn_ifaddr_notify(RTM_DELADDR, ifa1);
+	blocking_notifier_call_chain(&dnaddr_chain, NETDEV_DOWN, ifa1);
+	if (destroy) {
+		dn_dev_free_ifa(ifa1);
+
+		if (dn_db->ifa_list == NULL)
+			dn_dev_delete(dn_db->dev);
+	}
+}
+
+static int dn_dev_insert_ifa(struct dn_dev *dn_db, struct dn_ifaddr *ifa)
+{
+	struct net_device *dev = dn_db->dev;
+	struct dn_ifaddr *ifa1;
+	unsigned char mac_addr[6];
+
+	ASSERT_RTNL();
+
+	/* Check for duplicates */
+	for (ifa1 = rtnl_dereference(dn_db->ifa_list);
+	     ifa1 != NULL;
+	     ifa1 = rtnl_dereference(ifa1->ifa_next)) {
+		if (ifa1->ifa_local == ifa->ifa_local)
+			return -EEXIST;
+	}
+
+	if (dev->type == ARPHRD_ETHER) {
+		if (ifa->ifa_local != dn_eth2dn(dev->dev_addr)) {
+			dn_dn2eth(mac_addr, ifa->ifa_local);
+			dev_mc_add(dev, mac_addr);
+		}
+	}
+
+	ifa->ifa_next = dn_db->ifa_list;
+	rcu_assign_pointer(dn_db->ifa_list, ifa);
+
+	dn_ifaddr_notify(RTM_NEWADDR, ifa);
+	blocking_notifier_call_chain(&dnaddr_chain, NETDEV_UP, ifa);
+
+	return 0;
+}
+
+static int dn_dev_set_ifa(struct net_device *dev, struct dn_ifaddr *ifa)
+{
+	struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
+	int rv;
+
+	if (dn_db == NULL) {
+		int err;
+		dn_db = dn_dev_create(dev, &err);
+		if (dn_db == NULL)
+			return err;
+	}
+
+	ifa->ifa_dev = dn_db;
+
+	if (dev->flags & IFF_LOOPBACK)
+		ifa->ifa_scope = RT_SCOPE_HOST;
+
+	rv = dn_dev_insert_ifa(dn_db, ifa);
+	if (rv)
+		dn_dev_free_ifa(ifa);
+	return rv;
+}
+
+
+int dn_dev_ioctl(unsigned int cmd, void __user *arg)
+{
+	char buffer[DN_IFREQ_SIZE];
+	struct ifreq *ifr = (struct ifreq *)buffer;
+	struct sockaddr_dn *sdn = (struct sockaddr_dn *)&ifr->ifr_addr;
+	struct dn_dev *dn_db;
+	struct net_device *dev;
+	struct dn_ifaddr *ifa = NULL;
+	struct dn_ifaddr __rcu **ifap = NULL;
+	int ret = 0;
+
+	if (copy_from_user(ifr, arg, DN_IFREQ_SIZE))
+		return -EFAULT;
+	ifr->ifr_name[IFNAMSIZ-1] = 0;
+
+	dev_load(&init_net, ifr->ifr_name);
+
+	switch (cmd) {
+	case SIOCGIFADDR:
+		break;
+	case SIOCSIFADDR:
+		if (!capable(CAP_NET_ADMIN))
+			return -EACCES;
+		if (sdn->sdn_family != AF_DECnet)
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	rtnl_lock();
+
+	if ((dev = __dev_get_by_name(&init_net, ifr->ifr_name)) == NULL) {
+		ret = -ENODEV;
+		goto done;
+	}
+
+	if ((dn_db = rtnl_dereference(dev->dn_ptr)) != NULL) {
+		for (ifap = &dn_db->ifa_list;
+		     (ifa = rtnl_dereference(*ifap)) != NULL;
+		     ifap = &ifa->ifa_next)
+			if (strcmp(ifr->ifr_name, ifa->ifa_label) == 0)
+				break;
+	}
+
+	if (ifa == NULL && cmd != SIOCSIFADDR) {
+		ret = -EADDRNOTAVAIL;
+		goto done;
+	}
+
+	switch (cmd) {
+	case SIOCGIFADDR:
+		*((__le16 *)sdn->sdn_nodeaddr) = ifa->ifa_local;
+		goto rarok;
+
+	case SIOCSIFADDR:
+		if (!ifa) {
+			if ((ifa = dn_dev_alloc_ifa()) == NULL) {
+				ret = -ENOBUFS;
+				break;
+			}
+			memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
+		} else {
+			if (ifa->ifa_local == dn_saddr2dn(sdn))
+				break;
+			dn_dev_del_ifa(dn_db, ifap, 0);
+		}
+
+		ifa->ifa_local = ifa->ifa_address = dn_saddr2dn(sdn);
+
+		ret = dn_dev_set_ifa(dev, ifa);
+	}
+done:
+	rtnl_unlock();
+
+	return ret;
+rarok:
+	if (copy_to_user(arg, ifr, DN_IFREQ_SIZE))
+		ret = -EFAULT;
+	goto done;
+}
+
+struct net_device *dn_dev_get_default(void)
+{
+	struct net_device *dev;
+
+	spin_lock(&dndev_lock);
+	dev = decnet_default_device;
+	if (dev) {
+		if (dev->dn_ptr)
+			dev_hold(dev);
+		else
+			dev = NULL;
+	}
+	spin_unlock(&dndev_lock);
+
+	return dev;
+}
+
+int dn_dev_set_default(struct net_device *dev, int force)
+{
+	struct net_device *old = NULL;
+	int rv = -EBUSY;
+	if (!dev->dn_ptr)
+		return -ENODEV;
+
+	spin_lock(&dndev_lock);
+	if (force || decnet_default_device == NULL) {
+		old = decnet_default_device;
+		decnet_default_device = dev;
+		rv = 0;
+	}
+	spin_unlock(&dndev_lock);
+
+	if (old)
+		dev_put(old);
+	return rv;
+}
+
+static void dn_dev_check_default(struct net_device *dev)
+{
+	spin_lock(&dndev_lock);
+	if (dev == decnet_default_device) {
+		decnet_default_device = NULL;
+	} else {
+		dev = NULL;
+	}
+	spin_unlock(&dndev_lock);
+
+	if (dev)
+		dev_put(dev);
+}
+
+/*
+ * Called with RTNL
+ */
+static struct dn_dev *dn_dev_by_index(int ifindex)
+{
+	struct net_device *dev;
+	struct dn_dev *dn_dev = NULL;
+
+	dev = __dev_get_by_index(&init_net, ifindex);
+	if (dev)
+		dn_dev = rtnl_dereference(dev->dn_ptr);
+
+	return dn_dev;
+}
+
+static const struct nla_policy dn_ifa_policy[IFA_MAX+1] = {
+	[IFA_ADDRESS]		= { .type = NLA_U16 },
+	[IFA_LOCAL]		= { .type = NLA_U16 },
+	[IFA_LABEL]		= { .type = NLA_STRING,
+				    .len = IFNAMSIZ - 1 },
+	[IFA_FLAGS]		= { .type = NLA_U32 },
+};
+
+static int dn_nl_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
+			 struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct nlattr *tb[IFA_MAX+1];
+	struct dn_dev *dn_db;
+	struct ifaddrmsg *ifm;
+	struct dn_ifaddr *ifa;
+	struct dn_ifaddr __rcu **ifap;
+	int err = -EINVAL;
+
+	if (!netlink_capable(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (!net_eq(net, &init_net))
+		goto errout;
+
+	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, dn_ifa_policy,
+			  extack);
+	if (err < 0)
+		goto errout;
+
+	err = -ENODEV;
+	ifm = nlmsg_data(nlh);
+	if ((dn_db = dn_dev_by_index(ifm->ifa_index)) == NULL)
+		goto errout;
+
+	err = -EADDRNOTAVAIL;
+	for (ifap = &dn_db->ifa_list;
+	     (ifa = rtnl_dereference(*ifap)) != NULL;
+	     ifap = &ifa->ifa_next) {
+		if (tb[IFA_LOCAL] &&
+		    nla_memcmp(tb[IFA_LOCAL], &ifa->ifa_local, 2))
+			continue;
+
+		if (tb[IFA_LABEL] && nla_strcmp(tb[IFA_LABEL], ifa->ifa_label))
+			continue;
+
+		dn_dev_del_ifa(dn_db, ifap, 1);
+		return 0;
+	}
+
+errout:
+	return err;
+}
+
+static int dn_nl_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
+			 struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct nlattr *tb[IFA_MAX+1];
+	struct net_device *dev;
+	struct dn_dev *dn_db;
+	struct ifaddrmsg *ifm;
+	struct dn_ifaddr *ifa;
+	int err;
+
+	if (!netlink_capable(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (!net_eq(net, &init_net))
+		return -EINVAL;
+
+	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, dn_ifa_policy,
+			  extack);
+	if (err < 0)
+		return err;
+
+	if (tb[IFA_LOCAL] == NULL)
+		return -EINVAL;
+
+	ifm = nlmsg_data(nlh);
+	if ((dev = __dev_get_by_index(&init_net, ifm->ifa_index)) == NULL)
+		return -ENODEV;
+
+	if ((dn_db = rtnl_dereference(dev->dn_ptr)) == NULL) {
+		dn_db = dn_dev_create(dev, &err);
+		if (!dn_db)
+			return err;
+	}
+
+	if ((ifa = dn_dev_alloc_ifa()) == NULL)
+		return -ENOBUFS;
+
+	if (tb[IFA_ADDRESS] == NULL)
+		tb[IFA_ADDRESS] = tb[IFA_LOCAL];
+
+	ifa->ifa_local = nla_get_le16(tb[IFA_LOCAL]);
+	ifa->ifa_address = nla_get_le16(tb[IFA_ADDRESS]);
+	ifa->ifa_flags = tb[IFA_FLAGS] ? nla_get_u32(tb[IFA_FLAGS]) :
+					 ifm->ifa_flags;
+	ifa->ifa_scope = ifm->ifa_scope;
+	ifa->ifa_dev = dn_db;
+
+	if (tb[IFA_LABEL])
+		nla_strlcpy(ifa->ifa_label, tb[IFA_LABEL], IFNAMSIZ);
+	else
+		memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
+
+	err = dn_dev_insert_ifa(dn_db, ifa);
+	if (err)
+		dn_dev_free_ifa(ifa);
+
+	return err;
+}
+
+static inline size_t dn_ifaddr_nlmsg_size(void)
+{
+	return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
+	       + nla_total_size(IFNAMSIZ) /* IFA_LABEL */
+	       + nla_total_size(2) /* IFA_ADDRESS */
+	       + nla_total_size(2) /* IFA_LOCAL */
+	       + nla_total_size(4); /* IFA_FLAGS */
+}
+
+static int dn_nl_fill_ifaddr(struct sk_buff *skb, struct dn_ifaddr *ifa,
+			     u32 portid, u32 seq, int event, unsigned int flags)
+{
+	struct ifaddrmsg *ifm;
+	struct nlmsghdr *nlh;
+	u32 ifa_flags = ifa->ifa_flags | IFA_F_PERMANENT;
+
+	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*ifm), flags);
+	if (nlh == NULL)
+		return -EMSGSIZE;
+
+	ifm = nlmsg_data(nlh);
+	ifm->ifa_family = AF_DECnet;
+	ifm->ifa_prefixlen = 16;
+	ifm->ifa_flags = ifa_flags;
+	ifm->ifa_scope = ifa->ifa_scope;
+	ifm->ifa_index = ifa->ifa_dev->dev->ifindex;
+
+	if ((ifa->ifa_address &&
+	     nla_put_le16(skb, IFA_ADDRESS, ifa->ifa_address)) ||
+	    (ifa->ifa_local &&
+	     nla_put_le16(skb, IFA_LOCAL, ifa->ifa_local)) ||
+	    (ifa->ifa_label[0] &&
+	     nla_put_string(skb, IFA_LABEL, ifa->ifa_label)) ||
+	     nla_put_u32(skb, IFA_FLAGS, ifa_flags))
+		goto nla_put_failure;
+	nlmsg_end(skb, nlh);
+	return 0;
+
+nla_put_failure:
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
+}
+
+static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa)
+{
+	struct sk_buff *skb;
+	int err = -ENOBUFS;
+
+	skb = alloc_skb(dn_ifaddr_nlmsg_size(), GFP_KERNEL);
+	if (skb == NULL)
+		goto errout;
+
+	err = dn_nl_fill_ifaddr(skb, ifa, 0, 0, event, 0);
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in dn_ifaddr_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
+	rtnl_notify(skb, &init_net, 0, RTNLGRP_DECnet_IFADDR, NULL, GFP_KERNEL);
+	return;
+errout:
+	if (err < 0)
+		rtnl_set_sk_err(&init_net, RTNLGRP_DECnet_IFADDR, err);
+}
+
+static int dn_nl_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	int idx, dn_idx = 0, skip_ndevs, skip_naddr;
+	struct net_device *dev;
+	struct dn_dev *dn_db;
+	struct dn_ifaddr *ifa;
+
+	if (!net_eq(net, &init_net))
+		return 0;
+
+	skip_ndevs = cb->args[0];
+	skip_naddr = cb->args[1];
+
+	idx = 0;
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, dev) {
+		if (idx < skip_ndevs)
+			goto cont;
+		else if (idx > skip_ndevs) {
+			/* Only skip over addresses for first dev dumped
+			 * in this iteration (idx == skip_ndevs) */
+			skip_naddr = 0;
+		}
+
+		if ((dn_db = rcu_dereference(dev->dn_ptr)) == NULL)
+			goto cont;
+
+		for (ifa = rcu_dereference(dn_db->ifa_list), dn_idx = 0; ifa;
+		     ifa = rcu_dereference(ifa->ifa_next), dn_idx++) {
+			if (dn_idx < skip_naddr)
+				continue;
+
+			if (dn_nl_fill_ifaddr(skb, ifa, NETLINK_CB(cb->skb).portid,
+					      cb->nlh->nlmsg_seq, RTM_NEWADDR,
+					      NLM_F_MULTI) < 0)
+				goto done;
+		}
+cont:
+		idx++;
+	}
+done:
+	rcu_read_unlock();
+	cb->args[0] = idx;
+	cb->args[1] = dn_idx;
+
+	return skb->len;
+}
+
+static int dn_dev_get_first(struct net_device *dev, __le16 *addr)
+{
+	struct dn_dev *dn_db;
+	struct dn_ifaddr *ifa;
+	int rv = -ENODEV;
+
+	rcu_read_lock();
+	dn_db = rcu_dereference(dev->dn_ptr);
+	if (dn_db == NULL)
+		goto out;
+
+	ifa = rcu_dereference(dn_db->ifa_list);
+	if (ifa != NULL) {
+		*addr = ifa->ifa_local;
+		rv = 0;
+	}
+out:
+	rcu_read_unlock();
+	return rv;
+}
+
+/*
+ * Find a default address to bind to.
+ *
+ * This is one of those areas where the initial VMS concepts don't really
+ * map onto the Linux concepts, and since we introduced multiple addresses
+ * per interface we have to cope with slightly odd ways of finding out what
+ * "our address" really is. Mostly it's not a problem; for this we just guess
+ * a sensible default. Eventually the routing code will take care of all the
+ * nasties for us I hope.
+ */
+int dn_dev_bind_default(__le16 *addr)
+{
+	struct net_device *dev;
+	int rv;
+	dev = dn_dev_get_default();
+last_chance:
+	if (dev) {
+		rv = dn_dev_get_first(dev, addr);
+		dev_put(dev);
+		if (rv == 0 || dev == init_net.loopback_dev)
+			return rv;
+	}
+	dev = init_net.loopback_dev;
+	dev_hold(dev);
+	goto last_chance;
+}
+
+static void dn_send_endnode_hello(struct net_device *dev, struct dn_ifaddr *ifa)
+{
+	struct endnode_hello_message *msg;
+	struct sk_buff *skb = NULL;
+	__le16 *pktlen;
+	struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
+
+	if ((skb = dn_alloc_skb(NULL, sizeof(*msg), GFP_ATOMIC)) == NULL)
+		return;
+
+	skb->dev = dev;
+
+	msg = skb_put(skb, sizeof(*msg));
+
+	msg->msgflg  = 0x0D;
+	memcpy(msg->tiver, dn_eco_version, 3);
+	dn_dn2eth(msg->id, ifa->ifa_local);
+	msg->iinfo   = DN_RT_INFO_ENDN;
+	msg->blksize = cpu_to_le16(mtu2blksize(dev));
+	msg->area    = 0x00;
+	memset(msg->seed, 0, 8);
+	memcpy(msg->neighbor, dn_hiord, ETH_ALEN);
+
+	if (dn_db->router) {
+		struct dn_neigh *dn = (struct dn_neigh *)dn_db->router;
+		dn_dn2eth(msg->neighbor, dn->addr);
+	}
+
+	msg->timer   = cpu_to_le16((unsigned short)dn_db->parms.t3);
+	msg->mpd     = 0x00;
+	msg->datalen = 0x02;
+	memset(msg->data, 0xAA, 2);
+
+	pktlen = skb_push(skb, 2);
+	*pktlen = cpu_to_le16(skb->len - 2);
+
+	skb_reset_network_header(skb);
+
+	dn_rt_finish_output(skb, dn_rt_all_rt_mcast, msg->id);
+}
+
+
+#define DRDELAY (5 * HZ)
+
+static int dn_am_i_a_router(struct dn_neigh *dn, struct dn_dev *dn_db, struct dn_ifaddr *ifa)
+{
+	/* First check time since device went up */
+	if (time_before(jiffies, dn_db->uptime + DRDELAY))
+		return 0;
+
+	/* If there is no router, then yes... */
+	if (!dn_db->router)
+		return 1;
+
+	/* otherwise only if we have a higher priority or.. */
+	if (dn->priority < dn_db->parms.priority)
+		return 1;
+
+	/* if we have equal priority and a higher node number */
+	if (dn->priority != dn_db->parms.priority)
+		return 0;
+
+	if (le16_to_cpu(dn->addr) < le16_to_cpu(ifa->ifa_local))
+		return 1;
+
+	return 0;
+}
+
+static void dn_send_router_hello(struct net_device *dev, struct dn_ifaddr *ifa)
+{
+	int n;
+	struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
+	struct dn_neigh *dn = (struct dn_neigh *)dn_db->router;
+	struct sk_buff *skb;
+	size_t size;
+	unsigned char *ptr;
+	unsigned char *i1, *i2;
+	__le16 *pktlen;
+	char *src;
+
+	if (mtu2blksize(dev) < (26 + 7))
+		return;
+
+	n = mtu2blksize(dev) - 26;
+	n /= 7;
+
+	if (n > 32)
+		n = 32;
+
+	size = 2 + 26 + 7 * n;
+
+	if ((skb = dn_alloc_skb(NULL, size, GFP_ATOMIC)) == NULL)
+		return;
+
+	skb->dev = dev;
+	ptr = skb_put(skb, size);
+
+	*ptr++ = DN_RT_PKT_CNTL | DN_RT_PKT_ERTH;
+	*ptr++ = 2; /* ECO */
+	*ptr++ = 0;
+	*ptr++ = 0;
+	dn_dn2eth(ptr, ifa->ifa_local);
+	src = ptr;
+	ptr += ETH_ALEN;
+	*ptr++ = dn_db->parms.forwarding == 1 ?
+			DN_RT_INFO_L1RT : DN_RT_INFO_L2RT;
+	*((__le16 *)ptr) = cpu_to_le16(mtu2blksize(dev));
+	ptr += 2;
+	*ptr++ = dn_db->parms.priority; /* Priority */
+	*ptr++ = 0; /* Area: Reserved */
+	*((__le16 *)ptr) = cpu_to_le16((unsigned short)dn_db->parms.t3);
+	ptr += 2;
+	*ptr++ = 0; /* MPD: Reserved */
+	i1 = ptr++;
+	memset(ptr, 0, 7); /* Name: Reserved */
+	ptr += 7;
+	i2 = ptr++;
+
+	n = dn_neigh_elist(dev, ptr, n);
+
+	*i2 = 7 * n;
+	*i1 = 8 + *i2;
+
+	skb_trim(skb, (27 + *i2));
+
+	pktlen = skb_push(skb, 2);
+	*pktlen = cpu_to_le16(skb->len - 2);
+
+	skb_reset_network_header(skb);
+
+	if (dn_am_i_a_router(dn, dn_db, ifa)) {
+		struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
+		if (skb2) {
+			dn_rt_finish_output(skb2, dn_rt_all_end_mcast, src);
+		}
+	}
+
+	dn_rt_finish_output(skb, dn_rt_all_rt_mcast, src);
+}
+
+static void dn_send_brd_hello(struct net_device *dev, struct dn_ifaddr *ifa)
+{
+	struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
+
+	if (dn_db->parms.forwarding == 0)
+		dn_send_endnode_hello(dev, ifa);
+	else
+		dn_send_router_hello(dev, ifa);
+}
+
+static void dn_send_ptp_hello(struct net_device *dev, struct dn_ifaddr *ifa)
+{
+	int tdlen = 16;
+	int size = dev->hard_header_len + 2 + 4 + tdlen;
+	struct sk_buff *skb = dn_alloc_skb(NULL, size, GFP_ATOMIC);
+	int i;
+	unsigned char *ptr;
+	char src[ETH_ALEN];
+
+	if (skb == NULL)
+		return ;
+
+	skb->dev = dev;
+	skb_push(skb, dev->hard_header_len);
+	ptr = skb_put(skb, 2 + 4 + tdlen);
+
+	*ptr++ = DN_RT_PKT_HELO;
+	*((__le16 *)ptr) = ifa->ifa_local;
+	ptr += 2;
+	*ptr++ = tdlen;
+
+	for(i = 0; i < tdlen; i++)
+		*ptr++ = 0252;
+
+	dn_dn2eth(src, ifa->ifa_local);
+	dn_rt_finish_output(skb, dn_rt_all_rt_mcast, src);
+}
+
+static int dn_eth_up(struct net_device *dev)
+{
+	struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
+
+	if (dn_db->parms.forwarding == 0)
+		dev_mc_add(dev, dn_rt_all_end_mcast);
+	else
+		dev_mc_add(dev, dn_rt_all_rt_mcast);
+
+	dn_db->use_long = 1;
+
+	return 0;
+}
+
+static void dn_eth_down(struct net_device *dev)
+{
+	struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
+
+	if (dn_db->parms.forwarding == 0)
+		dev_mc_del(dev, dn_rt_all_end_mcast);
+	else
+		dev_mc_del(dev, dn_rt_all_rt_mcast);
+}
+
+static void dn_dev_set_timer(struct net_device *dev);
+
+static void dn_dev_timer_func(struct timer_list *t)
+{
+	struct dn_dev *dn_db = from_timer(dn_db, t, timer);
+	struct net_device *dev;
+	struct dn_ifaddr *ifa;
+
+	rcu_read_lock();
+	dev = dn_db->dev;
+	if (dn_db->t3 <= dn_db->parms.t2) {
+		if (dn_db->parms.timer3) {
+			for (ifa = rcu_dereference(dn_db->ifa_list);
+			     ifa;
+			     ifa = rcu_dereference(ifa->ifa_next)) {
+				if (!(ifa->ifa_flags & IFA_F_SECONDARY))
+					dn_db->parms.timer3(dev, ifa);
+			}
+		}
+		dn_db->t3 = dn_db->parms.t3;
+	} else {
+		dn_db->t3 -= dn_db->parms.t2;
+	}
+	rcu_read_unlock();
+	dn_dev_set_timer(dev);
+}
+
+static void dn_dev_set_timer(struct net_device *dev)
+{
+	struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
+
+	if (dn_db->parms.t2 > dn_db->parms.t3)
+		dn_db->parms.t2 = dn_db->parms.t3;
+
+	dn_db->timer.expires = jiffies + (dn_db->parms.t2 * HZ);
+
+	add_timer(&dn_db->timer);
+}
+
+static struct dn_dev *dn_dev_create(struct net_device *dev, int *err)
+{
+	int i;
+	struct dn_dev_parms *p = dn_dev_list;
+	struct dn_dev *dn_db;
+
+	for(i = 0; i < DN_DEV_LIST_SIZE; i++, p++) {
+		if (p->type == dev->type)
+			break;
+	}
+
+	*err = -ENODEV;
+	if (i == DN_DEV_LIST_SIZE)
+		return NULL;
+
+	*err = -ENOBUFS;
+	if ((dn_db = kzalloc(sizeof(struct dn_dev), GFP_ATOMIC)) == NULL)
+		return NULL;
+
+	memcpy(&dn_db->parms, p, sizeof(struct dn_dev_parms));
+
+	rcu_assign_pointer(dev->dn_ptr, dn_db);
+	dn_db->dev = dev;
+	timer_setup(&dn_db->timer, dn_dev_timer_func, 0);
+
+	dn_db->uptime = jiffies;
+
+	dn_db->neigh_parms = neigh_parms_alloc(dev, &dn_neigh_table);
+	if (!dn_db->neigh_parms) {
+		RCU_INIT_POINTER(dev->dn_ptr, NULL);
+		kfree(dn_db);
+		return NULL;
+	}
+
+	if (dn_db->parms.up) {
+		if (dn_db->parms.up(dev) < 0) {
+			neigh_parms_release(&dn_neigh_table, dn_db->neigh_parms);
+			dev->dn_ptr = NULL;
+			kfree(dn_db);
+			return NULL;
+		}
+	}
+
+	dn_dev_sysctl_register(dev, &dn_db->parms);
+
+	dn_dev_set_timer(dev);
+
+	*err = 0;
+	return dn_db;
+}
+
+
+/*
+ * This processes a device up event. We only start up
+ * the loopback device & ethernet devices with correct
+ * MAC addresses automatically. Others must be started
+ * specifically.
+ *
+ * FIXME: How should we configure the loopback address ? If we could dispense
+ * with using decnet_address here and for autobind, it will be one less thing
+ * for users to worry about setting up.
+ */
+
+void dn_dev_up(struct net_device *dev)
+{
+	struct dn_ifaddr *ifa;
+	__le16 addr = decnet_address;
+	int maybe_default = 0;
+	struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
+
+	if ((dev->type != ARPHRD_ETHER) && (dev->type != ARPHRD_LOOPBACK))
+		return;
+
+	/*
+	 * Need to ensure that loopback device has a dn_db attached to it
+	 * to allow creation of neighbours against it, even though it might
+	 * not have a local address of its own. Might as well do the same for
+	 * all autoconfigured interfaces.
+	 */
+	if (dn_db == NULL) {
+		int err;
+		dn_db = dn_dev_create(dev, &err);
+		if (dn_db == NULL)
+			return;
+	}
+
+	if (dev->type == ARPHRD_ETHER) {
+		if (memcmp(dev->dev_addr, dn_hiord, 4) != 0)
+			return;
+		addr = dn_eth2dn(dev->dev_addr);
+		maybe_default = 1;
+	}
+
+	if (addr == 0)
+		return;
+
+	if ((ifa = dn_dev_alloc_ifa()) == NULL)
+		return;
+
+	ifa->ifa_local = ifa->ifa_address = addr;
+	ifa->ifa_flags = 0;
+	ifa->ifa_scope = RT_SCOPE_UNIVERSE;
+	strcpy(ifa->ifa_label, dev->name);
+
+	dn_dev_set_ifa(dev, ifa);
+
+	/*
+	 * Automagically set the default device to the first automatically
+	 * configured ethernet card in the system.
+	 */
+	if (maybe_default) {
+		dev_hold(dev);
+		if (dn_dev_set_default(dev, 0))
+			dev_put(dev);
+	}
+}
+
+static void dn_dev_delete(struct net_device *dev)
+{
+	struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
+
+	if (dn_db == NULL)
+		return;
+
+	del_timer_sync(&dn_db->timer);
+	dn_dev_sysctl_unregister(&dn_db->parms);
+	dn_dev_check_default(dev);
+	neigh_ifdown(&dn_neigh_table, dev);
+
+	if (dn_db->parms.down)
+		dn_db->parms.down(dev);
+
+	dev->dn_ptr = NULL;
+
+	neigh_parms_release(&dn_neigh_table, dn_db->neigh_parms);
+	neigh_ifdown(&dn_neigh_table, dev);
+
+	if (dn_db->router)
+		neigh_release(dn_db->router);
+	if (dn_db->peer)
+		neigh_release(dn_db->peer);
+
+	kfree(dn_db);
+}
+
+void dn_dev_down(struct net_device *dev)
+{
+	struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
+	struct dn_ifaddr *ifa;
+
+	if (dn_db == NULL)
+		return;
+
+	while ((ifa = rtnl_dereference(dn_db->ifa_list)) != NULL) {
+		dn_dev_del_ifa(dn_db, &dn_db->ifa_list, 0);
+		dn_dev_free_ifa(ifa);
+	}
+
+	dn_dev_delete(dev);
+}
+
+void dn_dev_init_pkt(struct sk_buff *skb)
+{
+}
+
+void dn_dev_veri_pkt(struct sk_buff *skb)
+{
+}
+
+void dn_dev_hello(struct sk_buff *skb)
+{
+}
+
+void dn_dev_devices_off(void)
+{
+	struct net_device *dev;
+
+	rtnl_lock();
+	for_each_netdev(&init_net, dev)
+		dn_dev_down(dev);
+	rtnl_unlock();
+
+}
+
+void dn_dev_devices_on(void)
+{
+	struct net_device *dev;
+
+	rtnl_lock();
+	for_each_netdev(&init_net, dev) {
+		if (dev->flags & IFF_UP)
+			dn_dev_up(dev);
+	}
+	rtnl_unlock();
+}
+
+int register_dnaddr_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&dnaddr_chain, nb);
+}
+
+int unregister_dnaddr_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&dnaddr_chain, nb);
+}
+
+#ifdef CONFIG_PROC_FS
+static inline int is_dn_dev(struct net_device *dev)
+{
+	return dev->dn_ptr != NULL;
+}
+
+static void *dn_dev_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
+{
+	int i;
+	struct net_device *dev;
+
+	rcu_read_lock();
+
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	i = 1;
+	for_each_netdev_rcu(&init_net, dev) {
+		if (!is_dn_dev(dev))
+			continue;
+
+		if (i++ == *pos)
+			return dev;
+	}
+
+	return NULL;
+}
+
+static void *dn_dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct net_device *dev;
+
+	++*pos;
+
+	dev = v;
+	if (v == SEQ_START_TOKEN)
+		dev = net_device_entry(&init_net.dev_base_head);
+
+	for_each_netdev_continue_rcu(&init_net, dev) {
+		if (!is_dn_dev(dev))
+			continue;
+
+		return dev;
+	}
+
+	return NULL;
+}
+
+static void dn_dev_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static char *dn_type2asc(char type)
+{
+	switch (type) {
+	case DN_DEV_BCAST:
+		return "B";
+	case DN_DEV_UCAST:
+		return "U";
+	case DN_DEV_MPOINT:
+		return "M";
+	}
+
+	return "?";
+}
+
+static int dn_dev_seq_show(struct seq_file *seq, void *v)
+{
+	if (v == SEQ_START_TOKEN)
+		seq_puts(seq, "Name     Flags T1   Timer1 T3   Timer3 BlkSize Pri State DevType    Router Peer\n");
+	else {
+		struct net_device *dev = v;
+		char peer_buf[DN_ASCBUF_LEN];
+		char router_buf[DN_ASCBUF_LEN];
+		struct dn_dev *dn_db = rcu_dereference(dev->dn_ptr);
+
+		seq_printf(seq, "%-8s %1s     %04u %04u   %04lu %04lu"
+				"   %04hu    %03d %02x    %-10s %-7s %-7s\n",
+				dev->name ? dev->name : "???",
+				dn_type2asc(dn_db->parms.mode),
+				0, 0,
+				dn_db->t3, dn_db->parms.t3,
+				mtu2blksize(dev),
+				dn_db->parms.priority,
+				dn_db->parms.state, dn_db->parms.name,
+				dn_db->router ? dn_addr2asc(le16_to_cpu(*(__le16 *)dn_db->router->primary_key), router_buf) : "",
+				dn_db->peer ? dn_addr2asc(le16_to_cpu(*(__le16 *)dn_db->peer->primary_key), peer_buf) : "");
+	}
+	return 0;
+}
+
+static const struct seq_operations dn_dev_seq_ops = {
+	.start	= dn_dev_seq_start,
+	.next	= dn_dev_seq_next,
+	.stop	= dn_dev_seq_stop,
+	.show	= dn_dev_seq_show,
+};
+#endif /* CONFIG_PROC_FS */
+
+static int addr[2];
+module_param_array(addr, int, NULL, 0444);
+MODULE_PARM_DESC(addr, "The DECnet address of this machine: area,node");
+
+void __init dn_dev_init(void)
+{
+	if (addr[0] > 63 || addr[0] < 0) {
+		printk(KERN_ERR "DECnet: Area must be between 0 and 63");
+		return;
+	}
+
+	if (addr[1] > 1023 || addr[1] < 0) {
+		printk(KERN_ERR "DECnet: Node must be between 0 and 1023");
+		return;
+	}
+
+	decnet_address = cpu_to_le16((addr[0] << 10) | addr[1]);
+
+	dn_dev_devices_on();
+
+	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_NEWADDR,
+			     dn_nl_newaddr, NULL, 0);
+	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_DELADDR,
+			     dn_nl_deladdr, NULL, 0);
+	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETADDR,
+			     NULL, dn_nl_dump_ifaddr, 0);
+
+	proc_create_seq("decnet_dev", 0444, init_net.proc_net, &dn_dev_seq_ops);
+
+#ifdef CONFIG_SYSCTL
+	{
+		int i;
+		for(i = 0; i < DN_DEV_LIST_SIZE; i++)
+			dn_dev_sysctl_register(NULL, &dn_dev_list[i]);
+	}
+#endif /* CONFIG_SYSCTL */
+}
+
+void __exit dn_dev_cleanup(void)
+{
+#ifdef CONFIG_SYSCTL
+	{
+		int i;
+		for(i = 0; i < DN_DEV_LIST_SIZE; i++)
+			dn_dev_sysctl_unregister(&dn_dev_list[i]);
+	}
+#endif /* CONFIG_SYSCTL */
+
+	remove_proc_entry("decnet_dev", init_net.proc_net);
+
+	dn_dev_devices_off();
+}
diff --git a/net/decnet/dn_fib.c b/net/decnet/dn_fib.c
new file mode 100644
index 000000000..f78fe58ea
--- /dev/null
+++ b/net/decnet/dn_fib.c
@@ -0,0 +1,799 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Routing Forwarding Information Base (Glue/Info List)
+ *
+ * Author:      Steve Whitehouse <SteveW@ACM.org>
+ *
+ *
+ * Changes:
+ *              Alexey Kuznetsov : SMP locking changes
+ *              Steve Whitehouse : Rewrote it... Well to be more correct, I
+ *                                 copied most of it from the ipv4 fib code.
+ *              Steve Whitehouse : Updated it in style and fixed a few bugs
+ *                                 which were fixed in the ipv4 code since
+ *                                 this code was copied from it.
+ *
+ */
+#include <linux/string.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/slab.h>
+#include <linux/sockios.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/proc_fs.h>
+#include <linux/netdevice.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <linux/atomic.h>
+#include <linux/uaccess.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/flow.h>
+#include <net/fib_rules.h>
+#include <net/dn.h>
+#include <net/dn_route.h>
+#include <net/dn_fib.h>
+#include <net/dn_neigh.h>
+#include <net/dn_dev.h>
+#include <net/nexthop.h>
+
+#define RT_MIN_TABLE 1
+
+#define for_fib_info() { struct dn_fib_info *fi;\
+	for(fi = dn_fib_info_list; fi; fi = fi->fib_next)
+#define endfor_fib_info() }
+
+#define for_nexthops(fi) { int nhsel; const struct dn_fib_nh *nh;\
+	for(nhsel = 0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
+
+#define change_nexthops(fi) { int nhsel; struct dn_fib_nh *nh;\
+	for(nhsel = 0, nh = (struct dn_fib_nh *)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nh++, nhsel++)
+
+#define endfor_nexthops(fi) }
+
+static DEFINE_SPINLOCK(dn_fib_multipath_lock);
+static struct dn_fib_info *dn_fib_info_list;
+static DEFINE_SPINLOCK(dn_fib_info_lock);
+
+static struct
+{
+	int error;
+	u8 scope;
+} dn_fib_props[RTN_MAX+1] = {
+	[RTN_UNSPEC] =      { .error = 0,       .scope = RT_SCOPE_NOWHERE },
+	[RTN_UNICAST] =     { .error = 0,       .scope = RT_SCOPE_UNIVERSE },
+	[RTN_LOCAL] =       { .error = 0,       .scope = RT_SCOPE_HOST },
+	[RTN_BROADCAST] =   { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE },
+	[RTN_ANYCAST] =     { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE },
+	[RTN_MULTICAST] =   { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE },
+	[RTN_BLACKHOLE] =   { .error = -EINVAL, .scope = RT_SCOPE_UNIVERSE },
+	[RTN_UNREACHABLE] = { .error = -EHOSTUNREACH, .scope = RT_SCOPE_UNIVERSE },
+	[RTN_PROHIBIT] =    { .error = -EACCES, .scope = RT_SCOPE_UNIVERSE },
+	[RTN_THROW] =       { .error = -EAGAIN, .scope = RT_SCOPE_UNIVERSE },
+	[RTN_NAT] =         { .error = 0,       .scope = RT_SCOPE_NOWHERE },
+	[RTN_XRESOLVE] =    { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE },
+};
+
+static int dn_fib_sync_down(__le16 local, struct net_device *dev, int force);
+static int dn_fib_sync_up(struct net_device *dev);
+
+void dn_fib_free_info(struct dn_fib_info *fi)
+{
+	if (fi->fib_dead == 0) {
+		printk(KERN_DEBUG "DECnet: BUG! Attempt to free alive dn_fib_info\n");
+		return;
+	}
+
+	change_nexthops(fi) {
+		if (nh->nh_dev)
+			dev_put(nh->nh_dev);
+		nh->nh_dev = NULL;
+	} endfor_nexthops(fi);
+	kfree(fi);
+}
+
+void dn_fib_release_info(struct dn_fib_info *fi)
+{
+	spin_lock(&dn_fib_info_lock);
+	if (fi && --fi->fib_treeref == 0) {
+		if (fi->fib_next)
+			fi->fib_next->fib_prev = fi->fib_prev;
+		if (fi->fib_prev)
+			fi->fib_prev->fib_next = fi->fib_next;
+		if (fi == dn_fib_info_list)
+			dn_fib_info_list = fi->fib_next;
+		fi->fib_dead = 1;
+		dn_fib_info_put(fi);
+	}
+	spin_unlock(&dn_fib_info_lock);
+}
+
+static inline int dn_fib_nh_comp(const struct dn_fib_info *fi, const struct dn_fib_info *ofi)
+{
+	const struct dn_fib_nh *onh = ofi->fib_nh;
+
+	for_nexthops(fi) {
+		if (nh->nh_oif != onh->nh_oif ||
+			nh->nh_gw != onh->nh_gw ||
+			nh->nh_scope != onh->nh_scope ||
+			nh->nh_weight != onh->nh_weight ||
+			((nh->nh_flags^onh->nh_flags)&~RTNH_F_DEAD))
+				return -1;
+		onh++;
+	} endfor_nexthops(fi);
+	return 0;
+}
+
+static inline struct dn_fib_info *dn_fib_find_info(const struct dn_fib_info *nfi)
+{
+	for_fib_info() {
+		if (fi->fib_nhs != nfi->fib_nhs)
+			continue;
+		if (nfi->fib_protocol == fi->fib_protocol &&
+			nfi->fib_prefsrc == fi->fib_prefsrc &&
+			nfi->fib_priority == fi->fib_priority &&
+			memcmp(nfi->fib_metrics, fi->fib_metrics, sizeof(fi->fib_metrics)) == 0 &&
+			((nfi->fib_flags^fi->fib_flags)&~RTNH_F_DEAD) == 0 &&
+			(nfi->fib_nhs == 0 || dn_fib_nh_comp(fi, nfi) == 0))
+				return fi;
+	} endfor_fib_info();
+	return NULL;
+}
+
+static int dn_fib_count_nhs(const struct nlattr *attr)
+{
+	struct rtnexthop *nhp = nla_data(attr);
+	int nhs = 0, nhlen = nla_len(attr);
+
+	while (rtnh_ok(nhp, nhlen)) {
+		nhs++;
+		nhp = rtnh_next(nhp, &nhlen);
+	}
+
+	/* leftover implies invalid nexthop configuration, discard it */
+	return nhlen > 0 ? 0 : nhs;
+}
+
+static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct nlattr *attr,
+			  const struct rtmsg *r)
+{
+	struct rtnexthop *nhp = nla_data(attr);
+	int nhlen = nla_len(attr);
+
+	change_nexthops(fi) {
+		int attrlen;
+
+		if (!rtnh_ok(nhp, nhlen))
+			return -EINVAL;
+
+		nh->nh_flags  = (r->rtm_flags&~0xFF) | nhp->rtnh_flags;
+		nh->nh_oif    = nhp->rtnh_ifindex;
+		nh->nh_weight = nhp->rtnh_hops + 1;
+
+		attrlen = rtnh_attrlen(nhp);
+		if (attrlen > 0) {
+			struct nlattr *gw_attr;
+
+			gw_attr = nla_find((struct nlattr *) (nhp + 1), attrlen, RTA_GATEWAY);
+			nh->nh_gw = gw_attr ? nla_get_le16(gw_attr) : 0;
+		}
+
+		nhp = rtnh_next(nhp, &nhlen);
+	} endfor_nexthops(fi);
+
+	return 0;
+}
+
+
+static int dn_fib_check_nh(const struct rtmsg *r, struct dn_fib_info *fi, struct dn_fib_nh *nh)
+{
+	int err;
+
+	if (nh->nh_gw) {
+		struct flowidn fld;
+		struct dn_fib_res res;
+
+		if (nh->nh_flags&RTNH_F_ONLINK) {
+			struct net_device *dev;
+
+			if (r->rtm_scope >= RT_SCOPE_LINK)
+				return -EINVAL;
+			if (dnet_addr_type(nh->nh_gw) != RTN_UNICAST)
+				return -EINVAL;
+			if ((dev = __dev_get_by_index(&init_net, nh->nh_oif)) == NULL)
+				return -ENODEV;
+			if (!(dev->flags&IFF_UP))
+				return -ENETDOWN;
+			nh->nh_dev = dev;
+			dev_hold(dev);
+			nh->nh_scope = RT_SCOPE_LINK;
+			return 0;
+		}
+
+		memset(&fld, 0, sizeof(fld));
+		fld.daddr = nh->nh_gw;
+		fld.flowidn_oif = nh->nh_oif;
+		fld.flowidn_scope = r->rtm_scope + 1;
+
+		if (fld.flowidn_scope < RT_SCOPE_LINK)
+			fld.flowidn_scope = RT_SCOPE_LINK;
+
+		if ((err = dn_fib_lookup(&fld, &res)) != 0)
+			return err;
+
+		err = -EINVAL;
+		if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
+			goto out;
+		nh->nh_scope = res.scope;
+		nh->nh_oif = DN_FIB_RES_OIF(res);
+		nh->nh_dev = DN_FIB_RES_DEV(res);
+		if (nh->nh_dev == NULL)
+			goto out;
+		dev_hold(nh->nh_dev);
+		err = -ENETDOWN;
+		if (!(nh->nh_dev->flags & IFF_UP))
+			goto out;
+		err = 0;
+out:
+		dn_fib_res_put(&res);
+		return err;
+	} else {
+		struct net_device *dev;
+
+		if (nh->nh_flags&(RTNH_F_PERVASIVE|RTNH_F_ONLINK))
+			return -EINVAL;
+
+		dev = __dev_get_by_index(&init_net, nh->nh_oif);
+		if (dev == NULL || dev->dn_ptr == NULL)
+			return -ENODEV;
+		if (!(dev->flags&IFF_UP))
+			return -ENETDOWN;
+		nh->nh_dev = dev;
+		dev_hold(nh->nh_dev);
+		nh->nh_scope = RT_SCOPE_HOST;
+	}
+
+	return 0;
+}
+
+
+struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct nlattr *attrs[],
+				       const struct nlmsghdr *nlh, int *errp)
+{
+	int err;
+	struct dn_fib_info *fi = NULL;
+	struct dn_fib_info *ofi;
+	int nhs = 1;
+
+	if (r->rtm_type > RTN_MAX)
+		goto err_inval;
+
+	if (dn_fib_props[r->rtm_type].scope > r->rtm_scope)
+		goto err_inval;
+
+	if (attrs[RTA_MULTIPATH] &&
+	    (nhs = dn_fib_count_nhs(attrs[RTA_MULTIPATH])) == 0)
+		goto err_inval;
+
+	fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct dn_fib_nh), GFP_KERNEL);
+	err = -ENOBUFS;
+	if (fi == NULL)
+		goto failure;
+
+	fi->fib_protocol = r->rtm_protocol;
+	fi->fib_nhs = nhs;
+	fi->fib_flags = r->rtm_flags;
+
+	if (attrs[RTA_PRIORITY])
+		fi->fib_priority = nla_get_u32(attrs[RTA_PRIORITY]);
+
+	if (attrs[RTA_METRICS]) {
+		struct nlattr *attr;
+		int rem;
+
+		nla_for_each_nested(attr, attrs[RTA_METRICS], rem) {
+			int type = nla_type(attr);
+
+			if (type) {
+				if (type > RTAX_MAX || type == RTAX_CC_ALGO ||
+				    nla_len(attr) < 4)
+					goto err_inval;
+
+				fi->fib_metrics[type-1] = nla_get_u32(attr);
+			}
+		}
+	}
+
+	if (attrs[RTA_PREFSRC])
+		fi->fib_prefsrc = nla_get_le16(attrs[RTA_PREFSRC]);
+
+	if (attrs[RTA_MULTIPATH]) {
+		if ((err = dn_fib_get_nhs(fi, attrs[RTA_MULTIPATH], r)) != 0)
+			goto failure;
+
+		if (attrs[RTA_OIF] &&
+		    fi->fib_nh->nh_oif != nla_get_u32(attrs[RTA_OIF]))
+			goto err_inval;
+
+		if (attrs[RTA_GATEWAY] &&
+		    fi->fib_nh->nh_gw != nla_get_le16(attrs[RTA_GATEWAY]))
+			goto err_inval;
+	} else {
+		struct dn_fib_nh *nh = fi->fib_nh;
+
+		if (attrs[RTA_OIF])
+			nh->nh_oif = nla_get_u32(attrs[RTA_OIF]);
+
+		if (attrs[RTA_GATEWAY])
+			nh->nh_gw = nla_get_le16(attrs[RTA_GATEWAY]);
+
+		nh->nh_flags = r->rtm_flags;
+		nh->nh_weight = 1;
+	}
+
+	if (r->rtm_type == RTN_NAT) {
+		if (!attrs[RTA_GATEWAY] || nhs != 1 || attrs[RTA_OIF])
+			goto err_inval;
+
+		fi->fib_nh->nh_gw = nla_get_le16(attrs[RTA_GATEWAY]);
+		goto link_it;
+	}
+
+	if (dn_fib_props[r->rtm_type].error) {
+		if (attrs[RTA_GATEWAY] || attrs[RTA_OIF] || attrs[RTA_MULTIPATH])
+			goto err_inval;
+
+		goto link_it;
+	}
+
+	if (r->rtm_scope > RT_SCOPE_HOST)
+		goto err_inval;
+
+	if (r->rtm_scope == RT_SCOPE_HOST) {
+		struct dn_fib_nh *nh = fi->fib_nh;
+
+		/* Local address is added */
+		if (nhs != 1 || nh->nh_gw)
+			goto err_inval;
+		nh->nh_scope = RT_SCOPE_NOWHERE;
+		nh->nh_dev = dev_get_by_index(&init_net, fi->fib_nh->nh_oif);
+		err = -ENODEV;
+		if (nh->nh_dev == NULL)
+			goto failure;
+	} else {
+		change_nexthops(fi) {
+			if ((err = dn_fib_check_nh(r, fi, nh)) != 0)
+				goto failure;
+		} endfor_nexthops(fi)
+	}
+
+	if (fi->fib_prefsrc) {
+		if (r->rtm_type != RTN_LOCAL || !attrs[RTA_DST] ||
+		    fi->fib_prefsrc != nla_get_le16(attrs[RTA_DST]))
+			if (dnet_addr_type(fi->fib_prefsrc) != RTN_LOCAL)
+				goto err_inval;
+	}
+
+link_it:
+	if ((ofi = dn_fib_find_info(fi)) != NULL) {
+		fi->fib_dead = 1;
+		dn_fib_free_info(fi);
+		ofi->fib_treeref++;
+		return ofi;
+	}
+
+	fi->fib_treeref++;
+	refcount_set(&fi->fib_clntref, 1);
+	spin_lock(&dn_fib_info_lock);
+	fi->fib_next = dn_fib_info_list;
+	fi->fib_prev = NULL;
+	if (dn_fib_info_list)
+		dn_fib_info_list->fib_prev = fi;
+	dn_fib_info_list = fi;
+	spin_unlock(&dn_fib_info_lock);
+	return fi;
+
+err_inval:
+	err = -EINVAL;
+
+failure:
+	*errp = err;
+	if (fi) {
+		fi->fib_dead = 1;
+		dn_fib_free_info(fi);
+	}
+
+	return NULL;
+}
+
+int dn_fib_semantic_match(int type, struct dn_fib_info *fi, const struct flowidn *fld, struct dn_fib_res *res)
+{
+	int err = dn_fib_props[type].error;
+
+	if (err == 0) {
+		if (fi->fib_flags & RTNH_F_DEAD)
+			return 1;
+
+		res->fi = fi;
+
+		switch (type) {
+		case RTN_NAT:
+			DN_FIB_RES_RESET(*res);
+			refcount_inc(&fi->fib_clntref);
+			return 0;
+		case RTN_UNICAST:
+		case RTN_LOCAL:
+			for_nexthops(fi) {
+				if (nh->nh_flags & RTNH_F_DEAD)
+					continue;
+				if (!fld->flowidn_oif ||
+				    fld->flowidn_oif == nh->nh_oif)
+					break;
+			}
+			if (nhsel < fi->fib_nhs) {
+				res->nh_sel = nhsel;
+				refcount_inc(&fi->fib_clntref);
+				return 0;
+			}
+			endfor_nexthops(fi);
+			res->fi = NULL;
+			return 1;
+		default:
+			net_err_ratelimited("DECnet: impossible routing event : dn_fib_semantic_match type=%d\n",
+					    type);
+			res->fi = NULL;
+			return -EINVAL;
+		}
+	}
+	return err;
+}
+
+void dn_fib_select_multipath(const struct flowidn *fld, struct dn_fib_res *res)
+{
+	struct dn_fib_info *fi = res->fi;
+	int w;
+
+	spin_lock_bh(&dn_fib_multipath_lock);
+	if (fi->fib_power <= 0) {
+		int power = 0;
+		change_nexthops(fi) {
+			if (!(nh->nh_flags&RTNH_F_DEAD)) {
+				power += nh->nh_weight;
+				nh->nh_power = nh->nh_weight;
+			}
+		} endfor_nexthops(fi);
+		fi->fib_power = power;
+		if (power < 0) {
+			spin_unlock_bh(&dn_fib_multipath_lock);
+			res->nh_sel = 0;
+			return;
+		}
+	}
+
+	w = jiffies % fi->fib_power;
+
+	change_nexthops(fi) {
+		if (!(nh->nh_flags&RTNH_F_DEAD) && nh->nh_power) {
+			if ((w -= nh->nh_power) <= 0) {
+				nh->nh_power--;
+				fi->fib_power--;
+				res->nh_sel = nhsel;
+				spin_unlock_bh(&dn_fib_multipath_lock);
+				return;
+			}
+		}
+	} endfor_nexthops(fi);
+	res->nh_sel = 0;
+	spin_unlock_bh(&dn_fib_multipath_lock);
+}
+
+static inline u32 rtm_get_table(struct nlattr *attrs[], u8 table)
+{
+	if (attrs[RTA_TABLE])
+		table = nla_get_u32(attrs[RTA_TABLE]);
+
+	return table;
+}
+
+static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
+			       struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct dn_fib_table *tb;
+	struct rtmsg *r = nlmsg_data(nlh);
+	struct nlattr *attrs[RTA_MAX+1];
+	int err;
+
+	if (!netlink_capable(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (!net_eq(net, &init_net))
+		return -EINVAL;
+
+	err = nlmsg_parse(nlh, sizeof(*r), attrs, RTA_MAX, rtm_dn_policy,
+			  extack);
+	if (err < 0)
+		return err;
+
+	tb = dn_fib_get_table(rtm_get_table(attrs, r->rtm_table), 0);
+	if (!tb)
+		return -ESRCH;
+
+	return tb->delete(tb, r, attrs, nlh, &NETLINK_CB(skb));
+}
+
+static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
+			       struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct dn_fib_table *tb;
+	struct rtmsg *r = nlmsg_data(nlh);
+	struct nlattr *attrs[RTA_MAX+1];
+	int err;
+
+	if (!netlink_capable(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (!net_eq(net, &init_net))
+		return -EINVAL;
+
+	err = nlmsg_parse(nlh, sizeof(*r), attrs, RTA_MAX, rtm_dn_policy,
+			  extack);
+	if (err < 0)
+		return err;
+
+	tb = dn_fib_get_table(rtm_get_table(attrs, r->rtm_table), 1);
+	if (!tb)
+		return -ENOBUFS;
+
+	return tb->insert(tb, r, attrs, nlh, &NETLINK_CB(skb));
+}
+
+static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifaddr *ifa)
+{
+	struct dn_fib_table *tb;
+	struct {
+		struct nlmsghdr nlh;
+		struct rtmsg rtm;
+	} req;
+	struct {
+		struct nlattr hdr;
+		__le16 dst;
+	} dst_attr = {
+		.dst = dst,
+	};
+	struct {
+		struct nlattr hdr;
+		__le16 prefsrc;
+	} prefsrc_attr = {
+		.prefsrc = ifa->ifa_local,
+	};
+	struct {
+		struct nlattr hdr;
+		u32 oif;
+	} oif_attr = {
+		.oif = ifa->ifa_dev->dev->ifindex,
+	};
+	struct nlattr *attrs[RTA_MAX+1] = {
+		[RTA_DST] = (struct nlattr *) &dst_attr,
+		[RTA_PREFSRC] = (struct nlattr * ) &prefsrc_attr,
+		[RTA_OIF] = (struct nlattr *) &oif_attr,
+	};
+
+	memset(&req.rtm, 0, sizeof(req.rtm));
+
+	if (type == RTN_UNICAST)
+		tb = dn_fib_get_table(RT_MIN_TABLE, 1);
+	else
+		tb = dn_fib_get_table(RT_TABLE_LOCAL, 1);
+
+	if (tb == NULL)
+		return;
+
+	req.nlh.nlmsg_len = sizeof(req);
+	req.nlh.nlmsg_type = cmd;
+	req.nlh.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_APPEND;
+	req.nlh.nlmsg_pid = 0;
+	req.nlh.nlmsg_seq = 0;
+
+	req.rtm.rtm_dst_len = dst_len;
+	req.rtm.rtm_table = tb->n;
+	req.rtm.rtm_protocol = RTPROT_KERNEL;
+	req.rtm.rtm_scope = (type != RTN_LOCAL ? RT_SCOPE_LINK : RT_SCOPE_HOST);
+	req.rtm.rtm_type = type;
+
+	if (cmd == RTM_NEWROUTE)
+		tb->insert(tb, &req.rtm, attrs, &req.nlh, NULL);
+	else
+		tb->delete(tb, &req.rtm, attrs, &req.nlh, NULL);
+}
+
+static void dn_fib_add_ifaddr(struct dn_ifaddr *ifa)
+{
+
+	fib_magic(RTM_NEWROUTE, RTN_LOCAL, ifa->ifa_local, 16, ifa);
+
+#if 0
+	if (!(dev->flags&IFF_UP))
+		return;
+	/* In the future, we will want to add default routes here */
+
+#endif
+}
+
+static void dn_fib_del_ifaddr(struct dn_ifaddr *ifa)
+{
+	int found_it = 0;
+	struct net_device *dev;
+	struct dn_dev *dn_db;
+	struct dn_ifaddr *ifa2;
+
+	ASSERT_RTNL();
+
+	/* Scan device list */
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, dev) {
+		dn_db = rcu_dereference(dev->dn_ptr);
+		if (dn_db == NULL)
+			continue;
+		for (ifa2 = rcu_dereference(dn_db->ifa_list);
+		     ifa2 != NULL;
+		     ifa2 = rcu_dereference(ifa2->ifa_next)) {
+			if (ifa2->ifa_local == ifa->ifa_local) {
+				found_it = 1;
+				break;
+			}
+		}
+	}
+	rcu_read_unlock();
+
+	if (found_it == 0) {
+		fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 16, ifa);
+
+		if (dnet_addr_type(ifa->ifa_local) != RTN_LOCAL) {
+			if (dn_fib_sync_down(ifa->ifa_local, NULL, 0))
+				dn_fib_flush();
+		}
+	}
+}
+
+static void dn_fib_disable_addr(struct net_device *dev, int force)
+{
+	if (dn_fib_sync_down(0, dev, force))
+		dn_fib_flush();
+	dn_rt_cache_flush(0);
+	neigh_ifdown(&dn_neigh_table, dev);
+}
+
+static int dn_fib_dnaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	struct dn_ifaddr *ifa = (struct dn_ifaddr *)ptr;
+
+	switch (event) {
+	case NETDEV_UP:
+		dn_fib_add_ifaddr(ifa);
+		dn_fib_sync_up(ifa->ifa_dev->dev);
+		dn_rt_cache_flush(-1);
+		break;
+	case NETDEV_DOWN:
+		dn_fib_del_ifaddr(ifa);
+		if (ifa->ifa_dev && ifa->ifa_dev->ifa_list == NULL) {
+			dn_fib_disable_addr(ifa->ifa_dev->dev, 1);
+		} else {
+			dn_rt_cache_flush(-1);
+		}
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static int dn_fib_sync_down(__le16 local, struct net_device *dev, int force)
+{
+	int ret = 0;
+	int scope = RT_SCOPE_NOWHERE;
+
+	if (force)
+		scope = -1;
+
+	for_fib_info() {
+		/*
+		 * This makes no sense for DECnet.... we will almost
+		 * certainly have more than one local address the same
+		 * over all our interfaces. It needs thinking about
+		 * some more.
+		 */
+		if (local && fi->fib_prefsrc == local) {
+			fi->fib_flags |= RTNH_F_DEAD;
+			ret++;
+		} else if (dev && fi->fib_nhs) {
+			int dead = 0;
+
+			change_nexthops(fi) {
+				if (nh->nh_flags&RTNH_F_DEAD)
+					dead++;
+				else if (nh->nh_dev == dev &&
+						nh->nh_scope != scope) {
+					spin_lock_bh(&dn_fib_multipath_lock);
+					nh->nh_flags |= RTNH_F_DEAD;
+					fi->fib_power -= nh->nh_power;
+					nh->nh_power = 0;
+					spin_unlock_bh(&dn_fib_multipath_lock);
+					dead++;
+				}
+			} endfor_nexthops(fi)
+			if (dead == fi->fib_nhs) {
+				fi->fib_flags |= RTNH_F_DEAD;
+				ret++;
+			}
+		}
+	} endfor_fib_info();
+	return ret;
+}
+
+
+static int dn_fib_sync_up(struct net_device *dev)
+{
+	int ret = 0;
+
+	if (!(dev->flags&IFF_UP))
+		return 0;
+
+	for_fib_info() {
+		int alive = 0;
+
+		change_nexthops(fi) {
+			if (!(nh->nh_flags&RTNH_F_DEAD)) {
+				alive++;
+				continue;
+			}
+			if (nh->nh_dev == NULL || !(nh->nh_dev->flags&IFF_UP))
+				continue;
+			if (nh->nh_dev != dev || dev->dn_ptr == NULL)
+				continue;
+			alive++;
+			spin_lock_bh(&dn_fib_multipath_lock);
+			nh->nh_power = 0;
+			nh->nh_flags &= ~RTNH_F_DEAD;
+			spin_unlock_bh(&dn_fib_multipath_lock);
+		} endfor_nexthops(fi);
+
+		if (alive > 0) {
+			fi->fib_flags &= ~RTNH_F_DEAD;
+			ret++;
+		}
+	} endfor_fib_info();
+	return ret;
+}
+
+static struct notifier_block dn_fib_dnaddr_notifier = {
+	.notifier_call = dn_fib_dnaddr_event,
+};
+
+void __exit dn_fib_cleanup(void)
+{
+	dn_fib_table_cleanup();
+	dn_fib_rules_cleanup();
+
+	unregister_dnaddr_notifier(&dn_fib_dnaddr_notifier);
+}
+
+
+void __init dn_fib_init(void)
+{
+	dn_fib_table_init();
+	dn_fib_rules_init();
+
+	register_dnaddr_notifier(&dn_fib_dnaddr_notifier);
+
+	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_NEWROUTE,
+			     dn_fib_rtm_newroute, NULL, 0);
+	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_DELROUTE,
+			     dn_fib_rtm_delroute, NULL, 0);
+}
diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
new file mode 100644
index 000000000..94b306f6d
--- /dev/null
+++ b/net/decnet/dn_neigh.c
@@ -0,0 +1,605 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Neighbour Functions (Adjacency Database and
+ *                                                        On-Ethernet Cache)
+ *
+ * Author:      Steve Whitehouse <SteveW@ACM.org>
+ *
+ *
+ * Changes:
+ *     Steve Whitehouse     : Fixed router listing routine
+ *     Steve Whitehouse     : Added error_report functions
+ *     Steve Whitehouse     : Added default router detection
+ *     Steve Whitehouse     : Hop counts in outgoing messages
+ *     Steve Whitehouse     : Fixed src/dst in outgoing messages so
+ *                            forwarding now stands a good chance of
+ *                            working.
+ *     Steve Whitehouse     : Fixed neighbour states (for now anyway).
+ *     Steve Whitehouse     : Made error_report functions dummies. This
+ *                            is not the right place to return skbs.
+ *     Steve Whitehouse     : Convert to seq_file
+ *
+ */
+
+#include <linux/net.h>
+#include <linux/module.h>
+#include <linux/socket.h>
+#include <linux/if_arp.h>
+#include <linux/slab.h>
+#include <linux/if_ether.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/string.h>
+#include <linux/netfilter_decnet.h>
+#include <linux/spinlock.h>
+#include <linux/seq_file.h>
+#include <linux/rcupdate.h>
+#include <linux/jhash.h>
+#include <linux/atomic.h>
+#include <net/net_namespace.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/flow.h>
+#include <net/dn.h>
+#include <net/dn_dev.h>
+#include <net/dn_neigh.h>
+#include <net/dn_route.h>
+
+static int dn_neigh_construct(struct neighbour *);
+static void dn_neigh_error_report(struct neighbour *, struct sk_buff *);
+static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb);
+
+/*
+ * Operations for adding the link layer header.
+ */
+static const struct neigh_ops dn_neigh_ops = {
+	.family =		AF_DECnet,
+	.error_report =		dn_neigh_error_report,
+	.output =		dn_neigh_output,
+	.connected_output =	dn_neigh_output,
+};
+
+static u32 dn_neigh_hash(const void *pkey,
+			 const struct net_device *dev,
+			 __u32 *hash_rnd)
+{
+	return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
+}
+
+static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
+{
+	return neigh_key_eq16(neigh, pkey);
+}
+
+struct neigh_table dn_neigh_table = {
+	.family =			PF_DECnet,
+	.entry_size =			NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
+	.key_len =			sizeof(__le16),
+	.protocol =			cpu_to_be16(ETH_P_DNA_RT),
+	.hash =				dn_neigh_hash,
+	.key_eq =			dn_key_eq,
+	.constructor =			dn_neigh_construct,
+	.id =				"dn_neigh_cache",
+	.parms ={
+		.tbl =			&dn_neigh_table,
+		.reachable_time =	30 * HZ,
+		.data = {
+			[NEIGH_VAR_MCAST_PROBES] = 0,
+			[NEIGH_VAR_UCAST_PROBES] = 0,
+			[NEIGH_VAR_APP_PROBES] = 0,
+			[NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
+			[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
+			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
+			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
+			[NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
+			[NEIGH_VAR_PROXY_QLEN] = 0,
+			[NEIGH_VAR_ANYCAST_DELAY] = 0,
+			[NEIGH_VAR_PROXY_DELAY] = 0,
+			[NEIGH_VAR_LOCKTIME] = 1 * HZ,
+		},
+	},
+	.gc_interval =			30 * HZ,
+	.gc_thresh1 =			128,
+	.gc_thresh2 =			512,
+	.gc_thresh3 =			1024,
+};
+
+static int dn_neigh_construct(struct neighbour *neigh)
+{
+	struct net_device *dev = neigh->dev;
+	struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
+	struct dn_dev *dn_db;
+	struct neigh_parms *parms;
+
+	rcu_read_lock();
+	dn_db = rcu_dereference(dev->dn_ptr);
+	if (dn_db == NULL) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+
+	parms = dn_db->neigh_parms;
+	if (!parms) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+
+	__neigh_parms_put(neigh->parms);
+	neigh->parms = neigh_parms_clone(parms);
+	rcu_read_unlock();
+
+	neigh->ops = &dn_neigh_ops;
+	neigh->nud_state = NUD_NOARP;
+	neigh->output = neigh->ops->connected_output;
+
+	if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
+		memcpy(neigh->ha, dev->broadcast, dev->addr_len);
+	else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
+		dn_dn2eth(neigh->ha, dn->addr);
+	else {
+		net_dbg_ratelimited("Trying to create neigh for hw %d\n",
+				    dev->type);
+		return -EINVAL;
+	}
+
+	/*
+	 * Make an estimate of the remote block size by assuming that its
+	 * two less then the device mtu, which it true for ethernet (and
+	 * other things which support long format headers) since there is
+	 * an extra length field (of 16 bits) which isn't part of the
+	 * ethernet headers and which the DECnet specs won't admit is part
+	 * of the DECnet routing headers either.
+	 *
+	 * If we over estimate here its no big deal, the NSP negotiations
+	 * will prevent us from sending packets which are too large for the
+	 * remote node to handle. In any case this figure is normally updated
+	 * by a hello message in most cases.
+	 */
+	dn->blksize = dev->mtu - 2;
+
+	return 0;
+}
+
+static void dn_neigh_error_report(struct neighbour *neigh, struct sk_buff *skb)
+{
+	printk(KERN_DEBUG "dn_neigh_error_report: called\n");
+	kfree_skb(skb);
+}
+
+static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	struct dn_route *rt = (struct dn_route *)dst;
+	struct net_device *dev = neigh->dev;
+	char mac_addr[ETH_ALEN];
+	unsigned int seq;
+	int err;
+
+	dn_dn2eth(mac_addr, rt->rt_local_src);
+	do {
+		seq = read_seqbegin(&neigh->ha_lock);
+		err = dev_hard_header(skb, dev, ntohs(skb->protocol),
+				      neigh->ha, mac_addr, skb->len);
+	} while (read_seqretry(&neigh->ha_lock, seq));
+
+	if (err >= 0)
+		err = dev_queue_xmit(skb);
+	else {
+		kfree_skb(skb);
+		err = -EINVAL;
+	}
+	return err;
+}
+
+static int dn_neigh_output_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	struct dn_route *rt = (struct dn_route *)dst;
+	struct neighbour *neigh = rt->n;
+
+	return neigh->output(neigh, skb);
+}
+
+/*
+ * For talking to broadcast devices: Ethernet & PPP
+ */
+static int dn_long_output(struct neighbour *neigh, struct sock *sk,
+			  struct sk_buff *skb)
+{
+	struct net_device *dev = neigh->dev;
+	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
+	unsigned char *data;
+	struct dn_long_packet *lp;
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+
+
+	if (skb_headroom(skb) < headroom) {
+		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
+		if (skb2 == NULL) {
+			net_crit_ratelimited("dn_long_output: no memory\n");
+			kfree_skb(skb);
+			return -ENOBUFS;
+		}
+		consume_skb(skb);
+		skb = skb2;
+		net_info_ratelimited("dn_long_output: Increasing headroom\n");
+	}
+
+	data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
+	lp = (struct dn_long_packet *)(data+3);
+
+	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
+	*(data + 2) = 1 | DN_RT_F_PF; /* Padding */
+
+	lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
+	lp->d_area   = lp->d_subarea = 0;
+	dn_dn2eth(lp->d_id, cb->dst);
+	lp->s_area   = lp->s_subarea = 0;
+	dn_dn2eth(lp->s_id, cb->src);
+	lp->nl2      = 0;
+	lp->visit_ct = cb->hops & 0x3f;
+	lp->s_class  = 0;
+	lp->pt       = 0;
+
+	skb_reset_network_header(skb);
+
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
+		       &init_net, sk, skb, NULL, neigh->dev,
+		       dn_neigh_output_packet);
+}
+
+/*
+ * For talking to pointopoint and multidrop devices: DDCMP and X.25
+ */
+static int dn_short_output(struct neighbour *neigh, struct sock *sk,
+			   struct sk_buff *skb)
+{
+	struct net_device *dev = neigh->dev;
+	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
+	struct dn_short_packet *sp;
+	unsigned char *data;
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+
+
+	if (skb_headroom(skb) < headroom) {
+		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
+		if (skb2 == NULL) {
+			net_crit_ratelimited("dn_short_output: no memory\n");
+			kfree_skb(skb);
+			return -ENOBUFS;
+		}
+		consume_skb(skb);
+		skb = skb2;
+		net_info_ratelimited("dn_short_output: Increasing headroom\n");
+	}
+
+	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
+	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
+	sp = (struct dn_short_packet *)(data+2);
+
+	sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
+	sp->dstnode    = cb->dst;
+	sp->srcnode    = cb->src;
+	sp->forward    = cb->hops & 0x3f;
+
+	skb_reset_network_header(skb);
+
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
+		       &init_net, sk, skb, NULL, neigh->dev,
+		       dn_neigh_output_packet);
+}
+
+/*
+ * For talking to DECnet phase III nodes
+ * Phase 3 output is the same as short output, execpt that
+ * it clears the area bits before transmission.
+ */
+static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
+			    struct sk_buff *skb)
+{
+	struct net_device *dev = neigh->dev;
+	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
+	struct dn_short_packet *sp;
+	unsigned char *data;
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+
+	if (skb_headroom(skb) < headroom) {
+		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
+		if (skb2 == NULL) {
+			net_crit_ratelimited("dn_phase3_output: no memory\n");
+			kfree_skb(skb);
+			return -ENOBUFS;
+		}
+		consume_skb(skb);
+		skb = skb2;
+		net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
+	}
+
+	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
+	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
+	sp = (struct dn_short_packet *)(data + 2);
+
+	sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
+	sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
+	sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
+	sp->forward  = cb->hops & 0x3f;
+
+	skb_reset_network_header(skb);
+
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
+		       &init_net, sk, skb, NULL, neigh->dev,
+		       dn_neigh_output_packet);
+}
+
+int dn_to_neigh_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	struct dn_route *rt = (struct dn_route *) dst;
+	struct neighbour *neigh = rt->n;
+	struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
+	struct dn_dev *dn_db;
+	bool use_long;
+
+	rcu_read_lock();
+	dn_db = rcu_dereference(neigh->dev->dn_ptr);
+	if (dn_db == NULL) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+	use_long = dn_db->use_long;
+	rcu_read_unlock();
+
+	if (dn->flags & DN_NDFLAG_P3)
+		return dn_phase3_output(neigh, sk, skb);
+	if (use_long)
+		return dn_long_output(neigh, sk, skb);
+	else
+		return dn_short_output(neigh, sk, skb);
+}
+
+/*
+ * Unfortunately, the neighbour code uses the device in its hash
+ * function, so we don't get any advantage from it. This function
+ * basically does a neigh_lookup(), but without comparing the device
+ * field. This is required for the On-Ethernet cache
+ */
+
+/*
+ * Pointopoint link receives a hello message
+ */
+void dn_neigh_pointopoint_hello(struct sk_buff *skb)
+{
+	kfree_skb(skb);
+}
+
+/*
+ * Ethernet router hello message received
+ */
+int dn_neigh_router_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
+
+	struct neighbour *neigh;
+	struct dn_neigh *dn;
+	struct dn_dev *dn_db;
+	__le16 src;
+
+	src = dn_eth2dn(msg->id);
+
+	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
+
+	dn = container_of(neigh, struct dn_neigh, n);
+
+	if (neigh) {
+		write_lock(&neigh->lock);
+
+		neigh->used = jiffies;
+		dn_db = rcu_dereference(neigh->dev->dn_ptr);
+
+		if (!(neigh->nud_state & NUD_PERMANENT)) {
+			neigh->updated = jiffies;
+
+			if (neigh->dev->type == ARPHRD_ETHER)
+				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
+
+			dn->blksize  = le16_to_cpu(msg->blksize);
+			dn->priority = msg->priority;
+
+			dn->flags &= ~DN_NDFLAG_P3;
+
+			switch (msg->iinfo & DN_RT_INFO_TYPE) {
+			case DN_RT_INFO_L1RT:
+				dn->flags &=~DN_NDFLAG_R2;
+				dn->flags |= DN_NDFLAG_R1;
+				break;
+			case DN_RT_INFO_L2RT:
+				dn->flags |= DN_NDFLAG_R2;
+			}
+		}
+
+		/* Only use routers in our area */
+		if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
+			if (!dn_db->router) {
+				dn_db->router = neigh_clone(neigh);
+			} else {
+				if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
+					neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
+			}
+		}
+		write_unlock(&neigh->lock);
+		neigh_release(neigh);
+	}
+
+	kfree_skb(skb);
+	return 0;
+}
+
+/*
+ * Endnode hello message received
+ */
+int dn_neigh_endnode_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
+	struct neighbour *neigh;
+	struct dn_neigh *dn;
+	__le16 src;
+
+	src = dn_eth2dn(msg->id);
+
+	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
+
+	dn = container_of(neigh, struct dn_neigh, n);
+
+	if (neigh) {
+		write_lock(&neigh->lock);
+
+		neigh->used = jiffies;
+
+		if (!(neigh->nud_state & NUD_PERMANENT)) {
+			neigh->updated = jiffies;
+
+			if (neigh->dev->type == ARPHRD_ETHER)
+				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
+			dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
+			dn->blksize  = le16_to_cpu(msg->blksize);
+			dn->priority = 0;
+		}
+
+		write_unlock(&neigh->lock);
+		neigh_release(neigh);
+	}
+
+	kfree_skb(skb);
+	return 0;
+}
+
+static char *dn_find_slot(char *base, int max, int priority)
+{
+	int i;
+	unsigned char *min = NULL;
+
+	base += 6; /* skip first id */
+
+	for(i = 0; i < max; i++) {
+		if (!min || (*base < *min))
+			min = base;
+		base += 7; /* find next priority */
+	}
+
+	if (!min)
+		return NULL;
+
+	return (*min < priority) ? (min - 6) : NULL;
+}
+
+struct elist_cb_state {
+	struct net_device *dev;
+	unsigned char *ptr;
+	unsigned char *rs;
+	int t, n;
+};
+
+static void neigh_elist_cb(struct neighbour *neigh, void *_info)
+{
+	struct elist_cb_state *s = _info;
+	struct dn_neigh *dn;
+
+	if (neigh->dev != s->dev)
+		return;
+
+	dn = container_of(neigh, struct dn_neigh, n);
+	if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
+		return;
+
+	if (s->t == s->n)
+		s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
+	else
+		s->t++;
+	if (s->rs == NULL)
+		return;
+
+	dn_dn2eth(s->rs, dn->addr);
+	s->rs += 6;
+	*(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
+	*(s->rs) |= dn->priority;
+	s->rs++;
+}
+
+int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
+{
+	struct elist_cb_state state;
+
+	state.dev = dev;
+	state.t = 0;
+	state.n = n;
+	state.ptr = ptr;
+	state.rs = ptr;
+
+	neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
+
+	return state.t;
+}
+
+
+#ifdef CONFIG_PROC_FS
+
+static inline void dn_neigh_format_entry(struct seq_file *seq,
+					 struct neighbour *n)
+{
+	struct dn_neigh *dn = container_of(n, struct dn_neigh, n);
+	char buf[DN_ASCBUF_LEN];
+
+	read_lock(&n->lock);
+	seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
+		   dn_addr2asc(le16_to_cpu(dn->addr), buf),
+		   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
+		   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
+		   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
+		   dn->n.nud_state,
+		   refcount_read(&dn->n.refcnt),
+		   dn->blksize,
+		   (dn->n.dev) ? dn->n.dev->name : "?");
+	read_unlock(&n->lock);
+}
+
+static int dn_neigh_seq_show(struct seq_file *seq, void *v)
+{
+	if (v == SEQ_START_TOKEN) {
+		seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
+	} else {
+		dn_neigh_format_entry(seq, v);
+	}
+
+	return 0;
+}
+
+static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	return neigh_seq_start(seq, pos, &dn_neigh_table,
+			       NEIGH_SEQ_NEIGH_ONLY);
+}
+
+static const struct seq_operations dn_neigh_seq_ops = {
+	.start = dn_neigh_seq_start,
+	.next  = neigh_seq_next,
+	.stop  = neigh_seq_stop,
+	.show  = dn_neigh_seq_show,
+};
+#endif
+
+void __init dn_neigh_init(void)
+{
+	neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
+	proc_create_net("decnet_neigh", 0444, init_net.proc_net,
+			&dn_neigh_seq_ops, sizeof(struct neigh_seq_state));
+}
+
+void __exit dn_neigh_cleanup(void)
+{
+	remove_proc_entry("decnet_neigh", init_net.proc_net);
+	neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
+}
diff --git a/net/decnet/dn_nsp_in.c b/net/decnet/dn_nsp_in.c
new file mode 100644
index 000000000..2fb5e055b
--- /dev/null
+++ b/net/decnet/dn_nsp_in.c
@@ -0,0 +1,914 @@
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Network Services Protocol (Input)
+ *
+ * Author:      Eduardo Marcelo Serrat <emserrat@geocities.com>
+ *
+ * Changes:
+ *
+ *    Steve Whitehouse:  Split into dn_nsp_in.c and dn_nsp_out.c from
+ *                       original dn_nsp.c.
+ *    Steve Whitehouse:  Updated to work with my new routing architecture.
+ *    Steve Whitehouse:  Add changes from Eduardo Serrat's patches.
+ *    Steve Whitehouse:  Put all ack handling code in a common routine.
+ *    Steve Whitehouse:  Put other common bits into dn_nsp_rx()
+ *    Steve Whitehouse:  More checks on skb->len to catch bogus packets
+ *                       Fixed various race conditions and possible nasties.
+ *    Steve Whitehouse:  Now handles returned conninit frames.
+ *     David S. Miller:  New socket locking
+ *    Steve Whitehouse:  Fixed lockup when socket filtering was enabled.
+ *         Paul Koning:  Fix to push CC sockets into RUN when acks are
+ *                       received.
+ *    Steve Whitehouse:
+ *   Patrick Caulfield:  Checking conninits for correctness & sending of error
+ *                       responses.
+ *    Steve Whitehouse:  Added backlog congestion level return codes.
+ *   Patrick Caulfield:
+ *    Steve Whitehouse:  Added flow control support (outbound)
+ *    Steve Whitehouse:  Prepare for nonlinear skbs
+ */
+
+/******************************************************************************
+    (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    any later version.
+
+    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.
+*******************************************************************************/
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/inet.h>
+#include <linux/route.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/termios.h>
+#include <linux/interrupt.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/netfilter_decnet.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/dn.h>
+#include <net/dn_nsp.h>
+#include <net/dn_dev.h>
+#include <net/dn_route.h>
+
+extern int decnet_log_martians;
+
+static void dn_log_martian(struct sk_buff *skb, const char *msg)
+{
+	if (decnet_log_martians) {
+		char *devname = skb->dev ? skb->dev->name : "???";
+		struct dn_skb_cb *cb = DN_SKB_CB(skb);
+		net_info_ratelimited("DECnet: Martian packet (%s) dev=%s src=0x%04hx dst=0x%04hx srcport=0x%04hx dstport=0x%04hx\n",
+				     msg, devname,
+				     le16_to_cpu(cb->src),
+				     le16_to_cpu(cb->dst),
+				     le16_to_cpu(cb->src_port),
+				     le16_to_cpu(cb->dst_port));
+	}
+}
+
+/*
+ * For this function we've flipped the cross-subchannel bit
+ * if the message is an otherdata or linkservice message. Thus
+ * we can use it to work out what to update.
+ */
+static void dn_ack(struct sock *sk, struct sk_buff *skb, unsigned short ack)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	unsigned short type = ((ack >> 12) & 0x0003);
+	int wakeup = 0;
+
+	switch (type) {
+	case 0: /* ACK - Data */
+		if (dn_after(ack, scp->ackrcv_dat)) {
+			scp->ackrcv_dat = ack & 0x0fff;
+			wakeup |= dn_nsp_check_xmit_queue(sk, skb,
+							  &scp->data_xmit_queue,
+							  ack);
+		}
+		break;
+	case 1: /* NAK - Data */
+		break;
+	case 2: /* ACK - OtherData */
+		if (dn_after(ack, scp->ackrcv_oth)) {
+			scp->ackrcv_oth = ack & 0x0fff;
+			wakeup |= dn_nsp_check_xmit_queue(sk, skb,
+							  &scp->other_xmit_queue,
+							  ack);
+		}
+		break;
+	case 3: /* NAK - OtherData */
+		break;
+	}
+
+	if (wakeup && !sock_flag(sk, SOCK_DEAD))
+		sk->sk_state_change(sk);
+}
+
+/*
+ * This function is a universal ack processor.
+ */
+static int dn_process_ack(struct sock *sk, struct sk_buff *skb, int oth)
+{
+	__le16 *ptr = (__le16 *)skb->data;
+	int len = 0;
+	unsigned short ack;
+
+	if (skb->len < 2)
+		return len;
+
+	if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
+		skb_pull(skb, 2);
+		ptr++;
+		len += 2;
+		if ((ack & 0x4000) == 0) {
+			if (oth)
+				ack ^= 0x2000;
+			dn_ack(sk, skb, ack);
+		}
+	}
+
+	if (skb->len < 2)
+		return len;
+
+	if ((ack = le16_to_cpu(*ptr)) & 0x8000) {
+		skb_pull(skb, 2);
+		len += 2;
+		if ((ack & 0x4000) == 0) {
+			if (oth)
+				ack ^= 0x2000;
+			dn_ack(sk, skb, ack);
+		}
+	}
+
+	return len;
+}
+
+
+/**
+ * dn_check_idf - Check an image data field format is correct.
+ * @pptr: Pointer to pointer to image data
+ * @len: Pointer to length of image data
+ * @max: The maximum allowed length of the data in the image data field
+ * @follow_on: Check that this many bytes exist beyond the end of the image data
+ *
+ * Returns: 0 if ok, -1 on error
+ */
+static inline int dn_check_idf(unsigned char **pptr, int *len, unsigned char max, unsigned char follow_on)
+{
+	unsigned char *ptr = *pptr;
+	unsigned char flen = *ptr++;
+
+	(*len)--;
+	if (flen > max)
+		return -1;
+	if ((flen + follow_on) > *len)
+		return -1;
+
+	*len -= flen;
+	*pptr = ptr + flen;
+	return 0;
+}
+
+/*
+ * Table of reason codes to pass back to node which sent us a badly
+ * formed message, plus text messages for the log. A zero entry in
+ * the reason field means "don't reply" otherwise a disc init is sent with
+ * the specified reason code.
+ */
+static struct {
+	unsigned short reason;
+	const char *text;
+} ci_err_table[] = {
+ { 0,             "CI: Truncated message" },
+ { NSP_REASON_ID, "CI: Destination username error" },
+ { NSP_REASON_ID, "CI: Destination username type" },
+ { NSP_REASON_US, "CI: Source username error" },
+ { 0,             "CI: Truncated at menuver" },
+ { 0,             "CI: Truncated before access or user data" },
+ { NSP_REASON_IO, "CI: Access data format error" },
+ { NSP_REASON_IO, "CI: User data format error" }
+};
+
+/*
+ * This function uses a slightly different lookup method
+ * to find its sockets, since it searches on object name/number
+ * rather than port numbers. Various tests are done to ensure that
+ * the incoming data is in the correct format before it is queued to
+ * a socket.
+ */
+static struct sock *dn_find_listener(struct sk_buff *skb, unsigned short *reason)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct nsp_conn_init_msg *msg = (struct nsp_conn_init_msg *)skb->data;
+	struct sockaddr_dn dstaddr;
+	struct sockaddr_dn srcaddr;
+	unsigned char type = 0;
+	int dstlen;
+	int srclen;
+	unsigned char *ptr;
+	int len;
+	int err = 0;
+	unsigned char menuver;
+
+	memset(&dstaddr, 0, sizeof(struct sockaddr_dn));
+	memset(&srcaddr, 0, sizeof(struct sockaddr_dn));
+
+	/*
+	 * 1. Decode & remove message header
+	 */
+	cb->src_port = msg->srcaddr;
+	cb->dst_port = msg->dstaddr;
+	cb->services = msg->services;
+	cb->info     = msg->info;
+	cb->segsize  = le16_to_cpu(msg->segsize);
+
+	if (!pskb_may_pull(skb, sizeof(*msg)))
+		goto err_out;
+
+	skb_pull(skb, sizeof(*msg));
+
+	len = skb->len;
+	ptr = skb->data;
+
+	/*
+	 * 2. Check destination end username format
+	 */
+	dstlen = dn_username2sockaddr(ptr, len, &dstaddr, &type);
+	err++;
+	if (dstlen < 0)
+		goto err_out;
+
+	err++;
+	if (type > 1)
+		goto err_out;
+
+	len -= dstlen;
+	ptr += dstlen;
+
+	/*
+	 * 3. Check source end username format
+	 */
+	srclen = dn_username2sockaddr(ptr, len, &srcaddr, &type);
+	err++;
+	if (srclen < 0)
+		goto err_out;
+
+	len -= srclen;
+	ptr += srclen;
+	err++;
+	if (len < 1)
+		goto err_out;
+
+	menuver = *ptr;
+	ptr++;
+	len--;
+
+	/*
+	 * 4. Check that optional data actually exists if menuver says it does
+	 */
+	err++;
+	if ((menuver & (DN_MENUVER_ACC | DN_MENUVER_USR)) && (len < 1))
+		goto err_out;
+
+	/*
+	 * 5. Check optional access data format
+	 */
+	err++;
+	if (menuver & DN_MENUVER_ACC) {
+		if (dn_check_idf(&ptr, &len, 39, 1))
+			goto err_out;
+		if (dn_check_idf(&ptr, &len, 39, 1))
+			goto err_out;
+		if (dn_check_idf(&ptr, &len, 39, (menuver & DN_MENUVER_USR) ? 1 : 0))
+			goto err_out;
+	}
+
+	/*
+	 * 6. Check optional user data format
+	 */
+	err++;
+	if (menuver & DN_MENUVER_USR) {
+		if (dn_check_idf(&ptr, &len, 16, 0))
+			goto err_out;
+	}
+
+	/*
+	 * 7. Look up socket based on destination end username
+	 */
+	return dn_sklist_find_listener(&dstaddr);
+err_out:
+	dn_log_martian(skb, ci_err_table[err].text);
+	*reason = ci_err_table[err].reason;
+	return NULL;
+}
+
+
+static void dn_nsp_conn_init(struct sock *sk, struct sk_buff *skb)
+{
+	if (sk_acceptq_is_full(sk)) {
+		kfree_skb(skb);
+		return;
+	}
+
+	sk->sk_ack_backlog++;
+	skb_queue_tail(&sk->sk_receive_queue, skb);
+	sk->sk_state_change(sk);
+}
+
+static void dn_nsp_conn_conf(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct dn_scp *scp = DN_SK(sk);
+	unsigned char *ptr;
+
+	if (skb->len < 4)
+		goto out;
+
+	ptr = skb->data;
+	cb->services = *ptr++;
+	cb->info = *ptr++;
+	cb->segsize = le16_to_cpu(*(__le16 *)ptr);
+
+	if ((scp->state == DN_CI) || (scp->state == DN_CD)) {
+		scp->persist = 0;
+		scp->addrrem = cb->src_port;
+		sk->sk_state = TCP_ESTABLISHED;
+		scp->state = DN_RUN;
+		scp->services_rem = cb->services;
+		scp->info_rem = cb->info;
+		scp->segsize_rem = cb->segsize;
+
+		if ((scp->services_rem & NSP_FC_MASK) == NSP_FC_NONE)
+			scp->max_window = decnet_no_fc_max_cwnd;
+
+		if (skb->len > 0) {
+			u16 dlen = *skb->data;
+			if ((dlen <= 16) && (dlen <= skb->len)) {
+				scp->conndata_in.opt_optl = cpu_to_le16(dlen);
+				skb_copy_from_linear_data_offset(skb, 1,
+					      scp->conndata_in.opt_data, dlen);
+			}
+		}
+		dn_nsp_send_link(sk, DN_NOCHANGE, 0);
+		if (!sock_flag(sk, SOCK_DEAD))
+			sk->sk_state_change(sk);
+	}
+
+out:
+	kfree_skb(skb);
+}
+
+static void dn_nsp_conn_ack(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	if (scp->state == DN_CI) {
+		scp->state = DN_CD;
+		scp->persist = 0;
+	}
+
+	kfree_skb(skb);
+}
+
+static void dn_nsp_disc_init(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	unsigned short reason;
+
+	if (skb->len < 2)
+		goto out;
+
+	reason = le16_to_cpu(*(__le16 *)skb->data);
+	skb_pull(skb, 2);
+
+	scp->discdata_in.opt_status = cpu_to_le16(reason);
+	scp->discdata_in.opt_optl   = 0;
+	memset(scp->discdata_in.opt_data, 0, 16);
+
+	if (skb->len > 0) {
+		u16 dlen = *skb->data;
+		if ((dlen <= 16) && (dlen <= skb->len)) {
+			scp->discdata_in.opt_optl = cpu_to_le16(dlen);
+			skb_copy_from_linear_data_offset(skb, 1, scp->discdata_in.opt_data, dlen);
+		}
+	}
+
+	scp->addrrem = cb->src_port;
+	sk->sk_state = TCP_CLOSE;
+
+	switch (scp->state) {
+	case DN_CI:
+	case DN_CD:
+		scp->state = DN_RJ;
+		sk->sk_err = ECONNREFUSED;
+		break;
+	case DN_RUN:
+		sk->sk_shutdown |= SHUTDOWN_MASK;
+		scp->state = DN_DN;
+		break;
+	case DN_DI:
+		scp->state = DN_DIC;
+		break;
+	}
+
+	if (!sock_flag(sk, SOCK_DEAD)) {
+		if (sk->sk_socket->state != SS_UNCONNECTED)
+			sk->sk_socket->state = SS_DISCONNECTING;
+		sk->sk_state_change(sk);
+	}
+
+	/*
+	 * It appears that its possible for remote machines to send disc
+	 * init messages with no port identifier if we are in the CI and
+	 * possibly also the CD state. Obviously we shouldn't reply with
+	 * a message if we don't know what the end point is.
+	 */
+	if (scp->addrrem) {
+		dn_nsp_send_disc(sk, NSP_DISCCONF, NSP_REASON_DC, GFP_ATOMIC);
+	}
+	scp->persist_fxn = dn_destroy_timer;
+	scp->persist = dn_nsp_persist(sk);
+
+out:
+	kfree_skb(skb);
+}
+
+/*
+ * disc_conf messages are also called no_resources or no_link
+ * messages depending upon the "reason" field.
+ */
+static void dn_nsp_disc_conf(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	unsigned short reason;
+
+	if (skb->len != 2)
+		goto out;
+
+	reason = le16_to_cpu(*(__le16 *)skb->data);
+
+	sk->sk_state = TCP_CLOSE;
+
+	switch (scp->state) {
+	case DN_CI:
+		scp->state = DN_NR;
+		break;
+	case DN_DR:
+		if (reason == NSP_REASON_DC)
+			scp->state = DN_DRC;
+		if (reason == NSP_REASON_NL)
+			scp->state = DN_CN;
+		break;
+	case DN_DI:
+		scp->state = DN_DIC;
+		break;
+	case DN_RUN:
+		sk->sk_shutdown |= SHUTDOWN_MASK;
+		/* fall through */
+	case DN_CC:
+		scp->state = DN_CN;
+	}
+
+	if (!sock_flag(sk, SOCK_DEAD)) {
+		if (sk->sk_socket->state != SS_UNCONNECTED)
+			sk->sk_socket->state = SS_DISCONNECTING;
+		sk->sk_state_change(sk);
+	}
+
+	scp->persist_fxn = dn_destroy_timer;
+	scp->persist = dn_nsp_persist(sk);
+
+out:
+	kfree_skb(skb);
+}
+
+static void dn_nsp_linkservice(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	unsigned short segnum;
+	unsigned char lsflags;
+	signed char fcval;
+	int wake_up = 0;
+	char *ptr = skb->data;
+	unsigned char fctype = scp->services_rem & NSP_FC_MASK;
+
+	if (skb->len != 4)
+		goto out;
+
+	segnum = le16_to_cpu(*(__le16 *)ptr);
+	ptr += 2;
+	lsflags = *(unsigned char *)ptr++;
+	fcval = *ptr;
+
+	/*
+	 * Here we ignore erronous packets which should really
+	 * should cause a connection abort. It is not critical
+	 * for now though.
+	 */
+	if (lsflags & 0xf8)
+		goto out;
+
+	if (seq_next(scp->numoth_rcv, segnum)) {
+		seq_add(&scp->numoth_rcv, 1);
+		switch(lsflags & 0x04) { /* FCVAL INT */
+		case 0x00: /* Normal Request */
+			switch(lsflags & 0x03) { /* FCVAL MOD */
+			case 0x00: /* Request count */
+				if (fcval < 0) {
+					unsigned char p_fcval = -fcval;
+					if ((scp->flowrem_dat > p_fcval) &&
+					    (fctype == NSP_FC_SCMC)) {
+						scp->flowrem_dat -= p_fcval;
+					}
+				} else if (fcval > 0) {
+					scp->flowrem_dat += fcval;
+					wake_up = 1;
+				}
+				break;
+			case 0x01: /* Stop outgoing data */
+				scp->flowrem_sw = DN_DONTSEND;
+				break;
+			case 0x02: /* Ok to start again */
+				scp->flowrem_sw = DN_SEND;
+				dn_nsp_output(sk);
+				wake_up = 1;
+			}
+			break;
+		case 0x04: /* Interrupt Request */
+			if (fcval > 0) {
+				scp->flowrem_oth += fcval;
+				wake_up = 1;
+			}
+			break;
+		}
+		if (wake_up && !sock_flag(sk, SOCK_DEAD))
+			sk->sk_state_change(sk);
+	}
+
+	dn_nsp_send_oth_ack(sk);
+
+out:
+	kfree_skb(skb);
+}
+
+/*
+ * Copy of sock_queue_rcv_skb (from sock.h) without
+ * bh_lock_sock() (its already held when this is called) which
+ * also allows data and other data to be queued to a socket.
+ */
+static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig, struct sk_buff_head *queue)
+{
+	int err;
+
+	/* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
+	   number of warnings when compiling with -W --ANK
+	 */
+	if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
+	    (unsigned int)sk->sk_rcvbuf) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	err = sk_filter(sk, skb);
+	if (err)
+		goto out;
+
+	skb_set_owner_r(skb, sk);
+	skb_queue_tail(queue, skb);
+
+	if (!sock_flag(sk, SOCK_DEAD))
+		sk->sk_data_ready(sk);
+out:
+	return err;
+}
+
+static void dn_nsp_otherdata(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	unsigned short segnum;
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	int queued = 0;
+
+	if (skb->len < 2)
+		goto out;
+
+	cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
+	skb_pull(skb, 2);
+
+	if (seq_next(scp->numoth_rcv, segnum)) {
+
+		if (dn_queue_skb(sk, skb, SIGURG, &scp->other_receive_queue) == 0) {
+			seq_add(&scp->numoth_rcv, 1);
+			scp->other_report = 0;
+			queued = 1;
+		}
+	}
+
+	dn_nsp_send_oth_ack(sk);
+out:
+	if (!queued)
+		kfree_skb(skb);
+}
+
+static void dn_nsp_data(struct sock *sk, struct sk_buff *skb)
+{
+	int queued = 0;
+	unsigned short segnum;
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct dn_scp *scp = DN_SK(sk);
+
+	if (skb->len < 2)
+		goto out;
+
+	cb->segnum = segnum = le16_to_cpu(*(__le16 *)skb->data);
+	skb_pull(skb, 2);
+
+	if (seq_next(scp->numdat_rcv, segnum)) {
+		if (dn_queue_skb(sk, skb, SIGIO, &sk->sk_receive_queue) == 0) {
+			seq_add(&scp->numdat_rcv, 1);
+			queued = 1;
+		}
+
+		if ((scp->flowloc_sw == DN_SEND) && dn_congested(sk)) {
+			scp->flowloc_sw = DN_DONTSEND;
+			dn_nsp_send_link(sk, DN_DONTSEND, 0);
+		}
+	}
+
+	dn_nsp_send_data_ack(sk);
+out:
+	if (!queued)
+		kfree_skb(skb);
+}
+
+/*
+ * If one of our conninit messages is returned, this function
+ * deals with it. It puts the socket into the NO_COMMUNICATION
+ * state.
+ */
+static void dn_returned_conn_init(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	if (scp->state == DN_CI) {
+		scp->state = DN_NC;
+		sk->sk_state = TCP_CLOSE;
+		if (!sock_flag(sk, SOCK_DEAD))
+			sk->sk_state_change(sk);
+	}
+
+	kfree_skb(skb);
+}
+
+static int dn_nsp_no_socket(struct sk_buff *skb, unsigned short reason)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	int ret = NET_RX_DROP;
+
+	/* Must not reply to returned packets */
+	if (cb->rt_flags & DN_RT_F_RTS)
+		goto out;
+
+	if ((reason != NSP_REASON_OK) && ((cb->nsp_flags & 0x0c) == 0x08)) {
+		switch (cb->nsp_flags & 0x70) {
+		case 0x10:
+		case 0x60: /* (Retransmitted) Connect Init */
+			dn_nsp_return_disc(skb, NSP_DISCINIT, reason);
+			ret = NET_RX_SUCCESS;
+			break;
+		case 0x20: /* Connect Confirm */
+			dn_nsp_return_disc(skb, NSP_DISCCONF, reason);
+			ret = NET_RX_SUCCESS;
+			break;
+		}
+	}
+
+out:
+	kfree_skb(skb);
+	return ret;
+}
+
+static int dn_nsp_rx_packet(struct net *net, struct sock *sk2,
+			    struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct sock *sk = NULL;
+	unsigned char *ptr = (unsigned char *)skb->data;
+	unsigned short reason = NSP_REASON_NL;
+
+	if (!pskb_may_pull(skb, 2))
+		goto free_out;
+
+	skb_reset_transport_header(skb);
+	cb->nsp_flags = *ptr++;
+
+	if (decnet_debug_level & 2)
+		printk(KERN_DEBUG "dn_nsp_rx: Message type 0x%02x\n", (int)cb->nsp_flags);
+
+	if (cb->nsp_flags & 0x83)
+		goto free_out;
+
+	/*
+	 * Filter out conninits and useless packet types
+	 */
+	if ((cb->nsp_flags & 0x0c) == 0x08) {
+		switch (cb->nsp_flags & 0x70) {
+		case 0x00: /* NOP */
+		case 0x70: /* Reserved */
+		case 0x50: /* Reserved, Phase II node init */
+			goto free_out;
+		case 0x10:
+		case 0x60:
+			if (unlikely(cb->rt_flags & DN_RT_F_RTS))
+				goto free_out;
+			sk = dn_find_listener(skb, &reason);
+			goto got_it;
+		}
+	}
+
+	if (!pskb_may_pull(skb, 3))
+		goto free_out;
+
+	/*
+	 * Grab the destination address.
+	 */
+	cb->dst_port = *(__le16 *)ptr;
+	cb->src_port = 0;
+	ptr += 2;
+
+	/*
+	 * If not a connack, grab the source address too.
+	 */
+	if (pskb_may_pull(skb, 5)) {
+		cb->src_port = *(__le16 *)ptr;
+		ptr += 2;
+		skb_pull(skb, 5);
+	}
+
+	/*
+	 * Returned packets...
+	 * Swap src & dst and look up in the normal way.
+	 */
+	if (unlikely(cb->rt_flags & DN_RT_F_RTS)) {
+		swap(cb->dst_port, cb->src_port);
+		swap(cb->dst, cb->src);
+	}
+
+	/*
+	 * Find the socket to which this skb is destined.
+	 */
+	sk = dn_find_by_skb(skb);
+got_it:
+	if (sk != NULL) {
+		struct dn_scp *scp = DN_SK(sk);
+
+		/* Reset backoff */
+		scp->nsp_rxtshift = 0;
+
+		/*
+		 * We linearize everything except data segments here.
+		 */
+		if (cb->nsp_flags & ~0x60) {
+			if (unlikely(skb_linearize(skb)))
+				goto free_out;
+		}
+
+		return sk_receive_skb(sk, skb, 0);
+	}
+
+	return dn_nsp_no_socket(skb, reason);
+
+free_out:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+int dn_nsp_rx(struct sk_buff *skb)
+{
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN,
+		       &init_net, NULL, skb, skb->dev, NULL,
+		       dn_nsp_rx_packet);
+}
+
+/*
+ * This is the main receive routine for sockets. It is called
+ * from the above when the socket is not busy, and also from
+ * sock_release() when there is a backlog queued up.
+ */
+int dn_nsp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+
+	if (cb->rt_flags & DN_RT_F_RTS) {
+		if (cb->nsp_flags == 0x18 || cb->nsp_flags == 0x68)
+			dn_returned_conn_init(sk, skb);
+		else
+			kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	/*
+	 * Control packet.
+	 */
+	if ((cb->nsp_flags & 0x0c) == 0x08) {
+		switch (cb->nsp_flags & 0x70) {
+		case 0x10:
+		case 0x60:
+			dn_nsp_conn_init(sk, skb);
+			break;
+		case 0x20:
+			dn_nsp_conn_conf(sk, skb);
+			break;
+		case 0x30:
+			dn_nsp_disc_init(sk, skb);
+			break;
+		case 0x40:
+			dn_nsp_disc_conf(sk, skb);
+			break;
+		}
+
+	} else if (cb->nsp_flags == 0x24) {
+		/*
+		 * Special for connacks, 'cos they don't have
+		 * ack data or ack otherdata info.
+		 */
+		dn_nsp_conn_ack(sk, skb);
+	} else {
+		int other = 1;
+
+		/* both data and ack frames can kick a CC socket into RUN */
+		if ((scp->state == DN_CC) && !sock_flag(sk, SOCK_DEAD)) {
+			scp->state = DN_RUN;
+			sk->sk_state = TCP_ESTABLISHED;
+			sk->sk_state_change(sk);
+		}
+
+		if ((cb->nsp_flags & 0x1c) == 0)
+			other = 0;
+		if (cb->nsp_flags == 0x04)
+			other = 0;
+
+		/*
+		 * Read out ack data here, this applies equally
+		 * to data, other data, link serivce and both
+		 * ack data and ack otherdata.
+		 */
+		dn_process_ack(sk, skb, other);
+
+		/*
+		 * If we've some sort of data here then call a
+		 * suitable routine for dealing with it, otherwise
+		 * the packet is an ack and can be discarded.
+		 */
+		if ((cb->nsp_flags & 0x0c) == 0) {
+
+			if (scp->state != DN_RUN)
+				goto free_out;
+
+			switch (cb->nsp_flags) {
+			case 0x10: /* LS */
+				dn_nsp_linkservice(sk, skb);
+				break;
+			case 0x30: /* OD */
+				dn_nsp_otherdata(sk, skb);
+				break;
+			default:
+				dn_nsp_data(sk, skb);
+			}
+
+		} else { /* Ack, chuck it out here */
+free_out:
+			kfree_skb(skb);
+		}
+	}
+
+	return NET_RX_SUCCESS;
+}
diff --git a/net/decnet/dn_nsp_out.c b/net/decnet/dn_nsp_out.c
new file mode 100644
index 000000000..a1779de6b
--- /dev/null
+++ b/net/decnet/dn_nsp_out.c
@@ -0,0 +1,703 @@
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Network Services Protocol (Output)
+ *
+ * Author:      Eduardo Marcelo Serrat <emserrat@geocities.com>
+ *
+ * Changes:
+ *
+ *    Steve Whitehouse:  Split into dn_nsp_in.c and dn_nsp_out.c from
+ *                       original dn_nsp.c.
+ *    Steve Whitehouse:  Updated to work with my new routing architecture.
+ *    Steve Whitehouse:  Added changes from Eduardo Serrat's patches.
+ *    Steve Whitehouse:  Now conninits have the "return" bit set.
+ *    Steve Whitehouse:  Fixes to check alloc'd skbs are non NULL!
+ *                       Moved output state machine into one function
+ *    Steve Whitehouse:  New output state machine
+ *         Paul Koning:  Connect Confirm message fix.
+ *      Eduardo Serrat:  Fix to stop dn_nsp_do_disc() sending malformed packets.
+ *    Steve Whitehouse:  dn_nsp_output() and friends needed a spring clean
+ *    Steve Whitehouse:  Moved dn_nsp_send() in here from route.h
+ */
+
+/******************************************************************************
+    (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    any later version.
+
+    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.
+*******************************************************************************/
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/inet.h>
+#include <linux/route.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/termios.h>
+#include <linux/interrupt.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/if_packet.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/flow.h>
+#include <net/dn.h>
+#include <net/dn_nsp.h>
+#include <net/dn_dev.h>
+#include <net/dn_route.h>
+
+
+static int nsp_backoff[NSP_MAXRXTSHIFT + 1] = { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
+
+static void dn_nsp_send(struct sk_buff *skb)
+{
+	struct sock *sk = skb->sk;
+	struct dn_scp *scp = DN_SK(sk);
+	struct dst_entry *dst;
+	struct flowidn fld;
+
+	skb_reset_transport_header(skb);
+	scp->stamp = jiffies;
+
+	dst = sk_dst_check(sk, 0);
+	if (dst) {
+try_again:
+		skb_dst_set(skb, dst);
+		dst_output(&init_net, skb->sk, skb);
+		return;
+	}
+
+	memset(&fld, 0, sizeof(fld));
+	fld.flowidn_oif = sk->sk_bound_dev_if;
+	fld.saddr = dn_saddr2dn(&scp->addr);
+	fld.daddr = dn_saddr2dn(&scp->peer);
+	dn_sk_ports_copy(&fld, scp);
+	fld.flowidn_proto = DNPROTO_NSP;
+	if (dn_route_output_sock(&sk->sk_dst_cache, &fld, sk, 0) == 0) {
+		dst = sk_dst_get(sk);
+		sk->sk_route_caps = dst->dev->features;
+		goto try_again;
+	}
+
+	sk->sk_err = EHOSTUNREACH;
+	if (!sock_flag(sk, SOCK_DEAD))
+		sk->sk_state_change(sk);
+}
+
+
+/*
+ * If sk == NULL, then we assume that we are supposed to be making
+ * a routing layer skb. If sk != NULL, then we are supposed to be
+ * creating an skb for the NSP layer.
+ *
+ * The eventual aim is for each socket to have a cached header size
+ * for its outgoing packets, and to set hdr from this when sk != NULL.
+ */
+struct sk_buff *dn_alloc_skb(struct sock *sk, int size, gfp_t pri)
+{
+	struct sk_buff *skb;
+	int hdr = 64;
+
+	if ((skb = alloc_skb(size + hdr, pri)) == NULL)
+		return NULL;
+
+	skb->protocol = htons(ETH_P_DNA_RT);
+	skb->pkt_type = PACKET_OUTGOING;
+
+	if (sk)
+		skb_set_owner_w(skb, sk);
+
+	skb_reserve(skb, hdr);
+
+	return skb;
+}
+
+/*
+ * Calculate persist timer based upon the smoothed round
+ * trip time and the variance. Backoff according to the
+ * nsp_backoff[] array.
+ */
+unsigned long dn_nsp_persist(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	unsigned long t = ((scp->nsp_srtt >> 2) + scp->nsp_rttvar) >> 1;
+
+	t *= nsp_backoff[scp->nsp_rxtshift];
+
+	if (t < HZ) t = HZ;
+	if (t > (600*HZ)) t = (600*HZ);
+
+	if (scp->nsp_rxtshift < NSP_MAXRXTSHIFT)
+		scp->nsp_rxtshift++;
+
+	/* printk(KERN_DEBUG "rxtshift %lu, t=%lu\n", scp->nsp_rxtshift, t); */
+
+	return t;
+}
+
+/*
+ * This is called each time we get an estimate for the rtt
+ * on the link.
+ */
+static void dn_nsp_rtt(struct sock *sk, long rtt)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	long srtt = (long)scp->nsp_srtt;
+	long rttvar = (long)scp->nsp_rttvar;
+	long delta;
+
+	/*
+	 * If the jiffies clock flips over in the middle of timestamp
+	 * gathering this value might turn out negative, so we make sure
+	 * that is it always positive here.
+	 */
+	if (rtt < 0)
+		rtt = -rtt;
+	/*
+	 * Add new rtt to smoothed average
+	 */
+	delta = ((rtt << 3) - srtt);
+	srtt += (delta >> 3);
+	if (srtt >= 1)
+		scp->nsp_srtt = (unsigned long)srtt;
+	else
+		scp->nsp_srtt = 1;
+
+	/*
+	 * Add new rtt varience to smoothed varience
+	 */
+	delta >>= 1;
+	rttvar += ((((delta>0)?(delta):(-delta)) - rttvar) >> 2);
+	if (rttvar >= 1)
+		scp->nsp_rttvar = (unsigned long)rttvar;
+	else
+		scp->nsp_rttvar = 1;
+
+	/* printk(KERN_DEBUG "srtt=%lu rttvar=%lu\n", scp->nsp_srtt, scp->nsp_rttvar); */
+}
+
+/**
+ * dn_nsp_clone_and_send - Send a data packet by cloning it
+ * @skb: The packet to clone and transmit
+ * @gfp: memory allocation flag
+ *
+ * Clone a queued data or other data packet and transmit it.
+ *
+ * Returns: The number of times the packet has been sent previously
+ */
+static inline unsigned int dn_nsp_clone_and_send(struct sk_buff *skb,
+					     gfp_t gfp)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct sk_buff *skb2;
+	int ret = 0;
+
+	if ((skb2 = skb_clone(skb, gfp)) != NULL) {
+		ret = cb->xmit_count;
+		cb->xmit_count++;
+		cb->stamp = jiffies;
+		skb2->sk = skb->sk;
+		dn_nsp_send(skb2);
+	}
+
+	return ret;
+}
+
+/**
+ * dn_nsp_output - Try and send something from socket queues
+ * @sk: The socket whose queues are to be investigated
+ *
+ * Try and send the packet on the end of the data and other data queues.
+ * Other data gets priority over data, and if we retransmit a packet we
+ * reduce the window by dividing it in two.
+ *
+ */
+void dn_nsp_output(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct sk_buff *skb;
+	unsigned int reduce_win = 0;
+
+	/*
+	 * First we check for otherdata/linkservice messages
+	 */
+	if ((skb = skb_peek(&scp->other_xmit_queue)) != NULL)
+		reduce_win = dn_nsp_clone_and_send(skb, GFP_ATOMIC);
+
+	/*
+	 * If we may not send any data, we don't.
+	 * If we are still trying to get some other data down the
+	 * channel, we don't try and send any data.
+	 */
+	if (reduce_win || (scp->flowrem_sw != DN_SEND))
+		goto recalc_window;
+
+	if ((skb = skb_peek(&scp->data_xmit_queue)) != NULL)
+		reduce_win = dn_nsp_clone_and_send(skb, GFP_ATOMIC);
+
+	/*
+	 * If we've sent any frame more than once, we cut the
+	 * send window size in half. There is always a minimum
+	 * window size of one available.
+	 */
+recalc_window:
+	if (reduce_win) {
+		scp->snd_window >>= 1;
+		if (scp->snd_window < NSP_MIN_WINDOW)
+			scp->snd_window = NSP_MIN_WINDOW;
+	}
+}
+
+int dn_nsp_xmit_timeout(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	dn_nsp_output(sk);
+
+	if (!skb_queue_empty(&scp->data_xmit_queue) ||
+	    !skb_queue_empty(&scp->other_xmit_queue))
+		scp->persist = dn_nsp_persist(sk);
+
+	return 0;
+}
+
+static inline __le16 *dn_mk_common_header(struct dn_scp *scp, struct sk_buff *skb, unsigned char msgflag, int len)
+{
+	unsigned char *ptr = skb_push(skb, len);
+
+	BUG_ON(len < 5);
+
+	*ptr++ = msgflag;
+	*((__le16 *)ptr) = scp->addrrem;
+	ptr += 2;
+	*((__le16 *)ptr) = scp->addrloc;
+	ptr += 2;
+	return (__le16 __force *)ptr;
+}
+
+static __le16 *dn_mk_ack_header(struct sock *sk, struct sk_buff *skb, unsigned char msgflag, int hlen, int other)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	unsigned short acknum = scp->numdat_rcv & 0x0FFF;
+	unsigned short ackcrs = scp->numoth_rcv & 0x0FFF;
+	__le16 *ptr;
+
+	BUG_ON(hlen < 9);
+
+	scp->ackxmt_dat = acknum;
+	scp->ackxmt_oth = ackcrs;
+	acknum |= 0x8000;
+	ackcrs |= 0x8000;
+
+	/* If this is an "other data/ack" message, swap acknum and ackcrs */
+	if (other)
+		swap(acknum, ackcrs);
+
+	/* Set "cross subchannel" bit in ackcrs */
+	ackcrs |= 0x2000;
+
+	ptr = dn_mk_common_header(scp, skb, msgflag, hlen);
+
+	*ptr++ = cpu_to_le16(acknum);
+	*ptr++ = cpu_to_le16(ackcrs);
+
+	return ptr;
+}
+
+static __le16 *dn_nsp_mk_data_header(struct sock *sk, struct sk_buff *skb, int oth)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	__le16 *ptr = dn_mk_ack_header(sk, skb, cb->nsp_flags, 11, oth);
+
+	if (unlikely(oth)) {
+		cb->segnum = scp->numoth;
+		seq_add(&scp->numoth, 1);
+	} else {
+		cb->segnum = scp->numdat;
+		seq_add(&scp->numdat, 1);
+	}
+	*(ptr++) = cpu_to_le16(cb->segnum);
+
+	return ptr;
+}
+
+void dn_nsp_queue_xmit(struct sock *sk, struct sk_buff *skb,
+			gfp_t gfp, int oth)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	unsigned long t = ((scp->nsp_srtt >> 2) + scp->nsp_rttvar) >> 1;
+
+	cb->xmit_count = 0;
+	dn_nsp_mk_data_header(sk, skb, oth);
+
+	/*
+	 * Slow start: If we have been idle for more than
+	 * one RTT, then reset window to min size.
+	 */
+	if ((jiffies - scp->stamp) > t)
+		scp->snd_window = NSP_MIN_WINDOW;
+
+	if (oth)
+		skb_queue_tail(&scp->other_xmit_queue, skb);
+	else
+		skb_queue_tail(&scp->data_xmit_queue, skb);
+
+	if (scp->flowrem_sw != DN_SEND)
+		return;
+
+	dn_nsp_clone_and_send(skb, gfp);
+}
+
+
+int dn_nsp_check_xmit_queue(struct sock *sk, struct sk_buff *skb, struct sk_buff_head *q, unsigned short acknum)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct dn_scp *scp = DN_SK(sk);
+	struct sk_buff *skb2, *n, *ack = NULL;
+	int wakeup = 0;
+	int try_retrans = 0;
+	unsigned long reftime = cb->stamp;
+	unsigned long pkttime;
+	unsigned short xmit_count;
+	unsigned short segnum;
+
+	skb_queue_walk_safe(q, skb2, n) {
+		struct dn_skb_cb *cb2 = DN_SKB_CB(skb2);
+
+		if (dn_before_or_equal(cb2->segnum, acknum))
+			ack = skb2;
+
+		/* printk(KERN_DEBUG "ack: %s %04x %04x\n", ack ? "ACK" : "SKIP", (int)cb2->segnum, (int)acknum); */
+
+		if (ack == NULL)
+			continue;
+
+		/* printk(KERN_DEBUG "check_xmit_queue: %04x, %d\n", acknum, cb2->xmit_count); */
+
+		/* Does _last_ packet acked have xmit_count > 1 */
+		try_retrans = 0;
+		/* Remember to wake up the sending process */
+		wakeup = 1;
+		/* Keep various statistics */
+		pkttime = cb2->stamp;
+		xmit_count = cb2->xmit_count;
+		segnum = cb2->segnum;
+		/* Remove and drop ack'ed packet */
+		skb_unlink(ack, q);
+		kfree_skb(ack);
+		ack = NULL;
+
+		/*
+		 * We don't expect to see acknowledgements for packets we
+		 * haven't sent yet.
+		 */
+		WARN_ON(xmit_count == 0);
+
+		/*
+		 * If the packet has only been sent once, we can use it
+		 * to calculate the RTT and also open the window a little
+		 * further.
+		 */
+		if (xmit_count == 1) {
+			if (dn_equal(segnum, acknum))
+				dn_nsp_rtt(sk, (long)(pkttime - reftime));
+
+			if (scp->snd_window < scp->max_window)
+				scp->snd_window++;
+		}
+
+		/*
+		 * Packet has been sent more than once. If this is the last
+		 * packet to be acknowledged then we want to send the next
+		 * packet in the send queue again (assumes the remote host does
+		 * go-back-N error control).
+		 */
+		if (xmit_count > 1)
+			try_retrans = 1;
+	}
+
+	if (try_retrans)
+		dn_nsp_output(sk);
+
+	return wakeup;
+}
+
+void dn_nsp_send_data_ack(struct sock *sk)
+{
+	struct sk_buff *skb = NULL;
+
+	if ((skb = dn_alloc_skb(sk, 9, GFP_ATOMIC)) == NULL)
+		return;
+
+	skb_reserve(skb, 9);
+	dn_mk_ack_header(sk, skb, 0x04, 9, 0);
+	dn_nsp_send(skb);
+}
+
+void dn_nsp_send_oth_ack(struct sock *sk)
+{
+	struct sk_buff *skb = NULL;
+
+	if ((skb = dn_alloc_skb(sk, 9, GFP_ATOMIC)) == NULL)
+		return;
+
+	skb_reserve(skb, 9);
+	dn_mk_ack_header(sk, skb, 0x14, 9, 1);
+	dn_nsp_send(skb);
+}
+
+
+void dn_send_conn_ack (struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct sk_buff *skb = NULL;
+	struct nsp_conn_ack_msg *msg;
+
+	if ((skb = dn_alloc_skb(sk, 3, sk->sk_allocation)) == NULL)
+		return;
+
+	msg = skb_put(skb, 3);
+	msg->msgflg = 0x24;
+	msg->dstaddr = scp->addrrem;
+
+	dn_nsp_send(skb);
+}
+
+static int dn_nsp_retrans_conn_conf(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	if (scp->state == DN_CC)
+		dn_send_conn_conf(sk, GFP_ATOMIC);
+
+	return 0;
+}
+
+void dn_send_conn_conf(struct sock *sk, gfp_t gfp)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct sk_buff *skb = NULL;
+	struct nsp_conn_init_msg *msg;
+	__u8 len = (__u8)le16_to_cpu(scp->conndata_out.opt_optl);
+
+	if ((skb = dn_alloc_skb(sk, 50 + len, gfp)) == NULL)
+		return;
+
+	msg = skb_put(skb, sizeof(*msg));
+	msg->msgflg = 0x28;
+	msg->dstaddr = scp->addrrem;
+	msg->srcaddr = scp->addrloc;
+	msg->services = scp->services_loc;
+	msg->info = scp->info_loc;
+	msg->segsize = cpu_to_le16(scp->segsize_loc);
+
+	skb_put_u8(skb, len);
+
+	if (len > 0)
+		skb_put_data(skb, scp->conndata_out.opt_data, len);
+
+
+	dn_nsp_send(skb);
+
+	scp->persist = dn_nsp_persist(sk);
+	scp->persist_fxn = dn_nsp_retrans_conn_conf;
+}
+
+
+static __inline__ void dn_nsp_do_disc(struct sock *sk, unsigned char msgflg,
+			unsigned short reason, gfp_t gfp,
+			struct dst_entry *dst,
+			int ddl, unsigned char *dd, __le16 rem, __le16 loc)
+{
+	struct sk_buff *skb = NULL;
+	int size = 7 + ddl + ((msgflg == NSP_DISCINIT) ? 1 : 0);
+	unsigned char *msg;
+
+	if ((dst == NULL) || (rem == 0)) {
+		net_dbg_ratelimited("DECnet: dn_nsp_do_disc: BUG! Please report this to SteveW@ACM.org rem=%u dst=%p\n",
+				    le16_to_cpu(rem), dst);
+		return;
+	}
+
+	if ((skb = dn_alloc_skb(sk, size, gfp)) == NULL)
+		return;
+
+	msg = skb_put(skb, size);
+	*msg++ = msgflg;
+	*(__le16 *)msg = rem;
+	msg += 2;
+	*(__le16 *)msg = loc;
+	msg += 2;
+	*(__le16 *)msg = cpu_to_le16(reason);
+	msg += 2;
+	if (msgflg == NSP_DISCINIT)
+		*msg++ = ddl;
+
+	if (ddl) {
+		memcpy(msg, dd, ddl);
+	}
+
+	/*
+	 * This doesn't go via the dn_nsp_send() function since we need
+	 * to be able to send disc packets out which have no socket
+	 * associations.
+	 */
+	skb_dst_set(skb, dst_clone(dst));
+	dst_output(&init_net, skb->sk, skb);
+}
+
+
+void dn_nsp_send_disc(struct sock *sk, unsigned char msgflg,
+			unsigned short reason, gfp_t gfp)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	int ddl = 0;
+
+	if (msgflg == NSP_DISCINIT)
+		ddl = le16_to_cpu(scp->discdata_out.opt_optl);
+
+	if (reason == 0)
+		reason = le16_to_cpu(scp->discdata_out.opt_status);
+
+	dn_nsp_do_disc(sk, msgflg, reason, gfp, __sk_dst_get(sk), ddl,
+		scp->discdata_out.opt_data, scp->addrrem, scp->addrloc);
+}
+
+
+void dn_nsp_return_disc(struct sk_buff *skb, unsigned char msgflg,
+			unsigned short reason)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	int ddl = 0;
+	gfp_t gfp = GFP_ATOMIC;
+
+	dn_nsp_do_disc(NULL, msgflg, reason, gfp, skb_dst(skb), ddl,
+			NULL, cb->src_port, cb->dst_port);
+}
+
+
+void dn_nsp_send_link(struct sock *sk, unsigned char lsflags, char fcval)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct sk_buff *skb;
+	unsigned char *ptr;
+	gfp_t gfp = GFP_ATOMIC;
+
+	if ((skb = dn_alloc_skb(sk, DN_MAX_NSP_DATA_HEADER + 2, gfp)) == NULL)
+		return;
+
+	skb_reserve(skb, DN_MAX_NSP_DATA_HEADER);
+	ptr = skb_put(skb, 2);
+	DN_SKB_CB(skb)->nsp_flags = 0x10;
+	*ptr++ = lsflags;
+	*ptr = fcval;
+
+	dn_nsp_queue_xmit(sk, skb, gfp, 1);
+
+	scp->persist = dn_nsp_persist(sk);
+	scp->persist_fxn = dn_nsp_xmit_timeout;
+}
+
+static int dn_nsp_retrans_conninit(struct sock *sk)
+{
+	struct dn_scp *scp = DN_SK(sk);
+
+	if (scp->state == DN_CI)
+		dn_nsp_send_conninit(sk, NSP_RCI);
+
+	return 0;
+}
+
+void dn_nsp_send_conninit(struct sock *sk, unsigned char msgflg)
+{
+	struct dn_scp *scp = DN_SK(sk);
+	struct nsp_conn_init_msg *msg;
+	unsigned char aux;
+	unsigned char menuver;
+	struct dn_skb_cb *cb;
+	unsigned char type = 1;
+	gfp_t allocation = (msgflg == NSP_CI) ? sk->sk_allocation : GFP_ATOMIC;
+	struct sk_buff *skb = dn_alloc_skb(sk, 200, allocation);
+
+	if (!skb)
+		return;
+
+	cb  = DN_SKB_CB(skb);
+	msg = skb_put(skb, sizeof(*msg));
+
+	msg->msgflg	= msgflg;
+	msg->dstaddr	= 0x0000;		/* Remote Node will assign it*/
+
+	msg->srcaddr	= scp->addrloc;
+	msg->services	= scp->services_loc;	/* Requested flow control    */
+	msg->info	= scp->info_loc;	/* Version Number            */
+	msg->segsize	= cpu_to_le16(scp->segsize_loc);	/* Max segment size  */
+
+	if (scp->peer.sdn_objnum)
+		type = 0;
+
+	skb_put(skb, dn_sockaddr2username(&scp->peer,
+					  skb_tail_pointer(skb), type));
+	skb_put(skb, dn_sockaddr2username(&scp->addr,
+					  skb_tail_pointer(skb), 2));
+
+	menuver = DN_MENUVER_ACC | DN_MENUVER_USR;
+	if (scp->peer.sdn_flags & SDF_PROXY)
+		menuver |= DN_MENUVER_PRX;
+	if (scp->peer.sdn_flags & SDF_UICPROXY)
+		menuver |= DN_MENUVER_UIC;
+
+	skb_put_u8(skb, menuver);	/* Menu Version		*/
+
+	aux = scp->accessdata.acc_userl;
+	skb_put_u8(skb, aux);
+	if (aux > 0)
+		skb_put_data(skb, scp->accessdata.acc_user, aux);
+
+	aux = scp->accessdata.acc_passl;
+	skb_put_u8(skb, aux);
+	if (aux > 0)
+		skb_put_data(skb, scp->accessdata.acc_pass, aux);
+
+	aux = scp->accessdata.acc_accl;
+	skb_put_u8(skb, aux);
+	if (aux > 0)
+		skb_put_data(skb, scp->accessdata.acc_acc, aux);
+
+	aux = (__u8)le16_to_cpu(scp->conndata_out.opt_optl);
+	skb_put_u8(skb, aux);
+	if (aux > 0)
+		skb_put_data(skb, scp->conndata_out.opt_data, aux);
+
+	scp->persist = dn_nsp_persist(sk);
+	scp->persist_fxn = dn_nsp_retrans_conninit;
+
+	cb->rt_flags = DN_RT_F_RQR;
+
+	dn_nsp_send(skb);
+}
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
new file mode 100644
index 000000000..658191fba
--- /dev/null
+++ b/net/decnet/dn_route.c
@@ -0,0 +1,1929 @@
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Routing Functions (Endnode and Router)
+ *
+ * Authors:     Steve Whitehouse <SteveW@ACM.org>
+ *              Eduardo Marcelo Serrat <emserrat@geocities.com>
+ *
+ * Changes:
+ *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
+ *                                 "return-to-sender" bits on outgoing
+ *                                 packets.
+ *		Steve Whitehouse : Timeouts for cached routes.
+ *              Steve Whitehouse : Use dst cache for input routes too.
+ *              Steve Whitehouse : Fixed error values in dn_send_skb.
+ *              Steve Whitehouse : Rework routing functions to better fit
+ *                                 DECnet routing design
+ *              Alexey Kuznetsov : New SMP locking
+ *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
+ *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
+ *				   Fixed possible skb leak in rtnetlink funcs.
+ *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
+ *                                 Alexey Kuznetsov's finer grained locking
+ *                                 from ipv4/route.c.
+ *              Steve Whitehouse : Routing is now starting to look like a
+ *                                 sensible set of code now, mainly due to
+ *                                 my copying the IPv4 routing code. The
+ *                                 hooks here are modified and will continue
+ *                                 to evolve for a while.
+ *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
+ *                                 stuff. Look out raw sockets your days
+ *                                 are numbered!
+ *              Steve Whitehouse : Added return-to-sender functions. Added
+ *                                 backlog congestion level return codes.
+ *		Steve Whitehouse : Fixed bug where routes were set up with
+ *                                 no ref count on net devices.
+ *              Steve Whitehouse : RCU for the route cache
+ *              Steve Whitehouse : Preparations for the flow cache
+ *              Steve Whitehouse : Prepare for nonlinear skbs
+ */
+
+/******************************************************************************
+    (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    any later version.
+
+    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.
+*******************************************************************************/
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/inet.h>
+#include <linux/route.h>
+#include <linux/in_route.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/rtnetlink.h>
+#include <linux/string.h>
+#include <linux/netfilter_decnet.h>
+#include <linux/rcupdate.h>
+#include <linux/times.h>
+#include <linux/export.h>
+#include <asm/errno.h>
+#include <net/net_namespace.h>
+#include <net/netlink.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/flow.h>
+#include <net/fib_rules.h>
+#include <net/dn.h>
+#include <net/dn_dev.h>
+#include <net/dn_nsp.h>
+#include <net/dn_route.h>
+#include <net/dn_neigh.h>
+#include <net/dn_fib.h>
+
+struct dn_rt_hash_bucket
+{
+	struct dn_route __rcu *chain;
+	spinlock_t lock;
+};
+
+extern struct neigh_table dn_neigh_table;
+
+
+static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
+
+static const int dn_rt_min_delay = 2 * HZ;
+static const int dn_rt_max_delay = 10 * HZ;
+static const int dn_rt_mtu_expires = 10 * 60 * HZ;
+
+static unsigned long dn_rt_deadline;
+
+static int dn_dst_gc(struct dst_ops *ops);
+static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
+static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
+static unsigned int dn_dst_mtu(const struct dst_entry *dst);
+static void dn_dst_destroy(struct dst_entry *);
+static void dn_dst_ifdown(struct dst_entry *, struct net_device *dev, int how);
+static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
+static void dn_dst_link_failure(struct sk_buff *);
+static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
+			       struct sk_buff *skb , u32 mtu,
+			       bool confirm_neigh);
+static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
+			    struct sk_buff *skb);
+static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
+					     struct sk_buff *skb,
+					     const void *daddr);
+static int dn_route_input(struct sk_buff *);
+static void dn_run_flush(struct timer_list *unused);
+
+static struct dn_rt_hash_bucket *dn_rt_hash_table;
+static unsigned int dn_rt_hash_mask;
+
+static struct timer_list dn_route_timer;
+static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush);
+int decnet_dst_gc_interval = 2;
+
+static struct dst_ops dn_dst_ops = {
+	.family =		PF_DECnet,
+	.gc_thresh =		128,
+	.gc =			dn_dst_gc,
+	.check =		dn_dst_check,
+	.default_advmss =	dn_dst_default_advmss,
+	.mtu =			dn_dst_mtu,
+	.cow_metrics =		dst_cow_metrics_generic,
+	.destroy =		dn_dst_destroy,
+	.ifdown =		dn_dst_ifdown,
+	.negative_advice =	dn_dst_negative_advice,
+	.link_failure =		dn_dst_link_failure,
+	.update_pmtu =		dn_dst_update_pmtu,
+	.redirect =		dn_dst_redirect,
+	.neigh_lookup =		dn_dst_neigh_lookup,
+};
+
+static void dn_dst_destroy(struct dst_entry *dst)
+{
+	struct dn_route *rt = (struct dn_route *) dst;
+
+	if (rt->n)
+		neigh_release(rt->n);
+	dst_destroy_metrics_generic(dst);
+}
+
+static void dn_dst_ifdown(struct dst_entry *dst, struct net_device *dev, int how)
+{
+	if (how) {
+		struct dn_route *rt = (struct dn_route *) dst;
+		struct neighbour *n = rt->n;
+
+		if (n && n->dev == dev) {
+			n->dev = dev_net(dev)->loopback_dev;
+			dev_hold(n->dev);
+			dev_put(dev);
+		}
+	}
+}
+
+static __inline__ unsigned int dn_hash(__le16 src, __le16 dst)
+{
+	__u16 tmp = (__u16 __force)(src ^ dst);
+	tmp ^= (tmp >> 3);
+	tmp ^= (tmp >> 5);
+	tmp ^= (tmp >> 10);
+	return dn_rt_hash_mask & (unsigned int)tmp;
+}
+
+static void dn_dst_check_expire(struct timer_list *unused)
+{
+	int i;
+	struct dn_route *rt;
+	struct dn_route __rcu **rtp;
+	unsigned long now = jiffies;
+	unsigned long expire = 120 * HZ;
+
+	for (i = 0; i <= dn_rt_hash_mask; i++) {
+		rtp = &dn_rt_hash_table[i].chain;
+
+		spin_lock(&dn_rt_hash_table[i].lock);
+		while ((rt = rcu_dereference_protected(*rtp,
+						lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
+			if (atomic_read(&rt->dst.__refcnt) > 1 ||
+			    (now - rt->dst.lastuse) < expire) {
+				rtp = &rt->dn_next;
+				continue;
+			}
+			*rtp = rt->dn_next;
+			rt->dn_next = NULL;
+			dst_dev_put(&rt->dst);
+			dst_release(&rt->dst);
+		}
+		spin_unlock(&dn_rt_hash_table[i].lock);
+
+		if ((jiffies - now) > 0)
+			break;
+	}
+
+	mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
+}
+
+static int dn_dst_gc(struct dst_ops *ops)
+{
+	struct dn_route *rt;
+	struct dn_route __rcu **rtp;
+	int i;
+	unsigned long now = jiffies;
+	unsigned long expire = 10 * HZ;
+
+	for (i = 0; i <= dn_rt_hash_mask; i++) {
+
+		spin_lock_bh(&dn_rt_hash_table[i].lock);
+		rtp = &dn_rt_hash_table[i].chain;
+
+		while ((rt = rcu_dereference_protected(*rtp,
+						lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
+			if (atomic_read(&rt->dst.__refcnt) > 1 ||
+			    (now - rt->dst.lastuse) < expire) {
+				rtp = &rt->dn_next;
+				continue;
+			}
+			*rtp = rt->dn_next;
+			rt->dn_next = NULL;
+			dst_dev_put(&rt->dst);
+			dst_release(&rt->dst);
+			break;
+		}
+		spin_unlock_bh(&dn_rt_hash_table[i].lock);
+	}
+
+	return 0;
+}
+
+/*
+ * The decnet standards don't impose a particular minimum mtu, what they
+ * do insist on is that the routing layer accepts a datagram of at least
+ * 230 bytes long. Here we have to subtract the routing header length from
+ * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
+ * assume the worst and use a long header size.
+ *
+ * We update both the mtu and the advertised mss (i.e. the segment size we
+ * advertise to the other end).
+ */
+static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
+			       struct sk_buff *skb, u32 mtu,
+			       bool confirm_neigh)
+{
+	struct dn_route *rt = (struct dn_route *) dst;
+	struct neighbour *n = rt->n;
+	u32 min_mtu = 230;
+	struct dn_dev *dn;
+
+	dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
+
+	if (dn && dn->use_long == 0)
+		min_mtu -= 6;
+	else
+		min_mtu -= 21;
+
+	if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
+		if (!(dst_metric_locked(dst, RTAX_MTU))) {
+			dst_metric_set(dst, RTAX_MTU, mtu);
+			dst_set_expires(dst, dn_rt_mtu_expires);
+		}
+		if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
+			u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
+			u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
+			if (!existing_mss || existing_mss > mss)
+				dst_metric_set(dst, RTAX_ADVMSS, mss);
+		}
+	}
+}
+
+static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
+			    struct sk_buff *skb)
+{
+}
+
+/*
+ * When a route has been marked obsolete. (e.g. routing cache flush)
+ */
+static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
+{
+	return NULL;
+}
+
+static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
+{
+	dst_release(dst);
+	return NULL;
+}
+
+static void dn_dst_link_failure(struct sk_buff *skb)
+{
+}
+
+static inline int compare_keys(struct flowidn *fl1, struct flowidn *fl2)
+{
+	return ((fl1->daddr ^ fl2->daddr) |
+		(fl1->saddr ^ fl2->saddr) |
+		(fl1->flowidn_mark ^ fl2->flowidn_mark) |
+		(fl1->flowidn_scope ^ fl2->flowidn_scope) |
+		(fl1->flowidn_oif ^ fl2->flowidn_oif) |
+		(fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0;
+}
+
+static int dn_insert_route(struct dn_route *rt, unsigned int hash, struct dn_route **rp)
+{
+	struct dn_route *rth;
+	struct dn_route __rcu **rthp;
+	unsigned long now = jiffies;
+
+	rthp = &dn_rt_hash_table[hash].chain;
+
+	spin_lock_bh(&dn_rt_hash_table[hash].lock);
+	while ((rth = rcu_dereference_protected(*rthp,
+						lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
+		if (compare_keys(&rth->fld, &rt->fld)) {
+			/* Put it first */
+			*rthp = rth->dn_next;
+			rcu_assign_pointer(rth->dn_next,
+					   dn_rt_hash_table[hash].chain);
+			rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
+
+			dst_hold_and_use(&rth->dst, now);
+			spin_unlock_bh(&dn_rt_hash_table[hash].lock);
+
+			dst_release_immediate(&rt->dst);
+			*rp = rth;
+			return 0;
+		}
+		rthp = &rth->dn_next;
+	}
+
+	rcu_assign_pointer(rt->dn_next, dn_rt_hash_table[hash].chain);
+	rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
+
+	dst_hold_and_use(&rt->dst, now);
+	spin_unlock_bh(&dn_rt_hash_table[hash].lock);
+	*rp = rt;
+	return 0;
+}
+
+static void dn_run_flush(struct timer_list *unused)
+{
+	int i;
+	struct dn_route *rt, *next;
+
+	for (i = 0; i < dn_rt_hash_mask; i++) {
+		spin_lock_bh(&dn_rt_hash_table[i].lock);
+
+		if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
+			goto nothing_to_declare;
+
+		for(; rt; rt = next) {
+			next = rcu_dereference_raw(rt->dn_next);
+			RCU_INIT_POINTER(rt->dn_next, NULL);
+			dst_dev_put(&rt->dst);
+			dst_release(&rt->dst);
+		}
+
+nothing_to_declare:
+		spin_unlock_bh(&dn_rt_hash_table[i].lock);
+	}
+}
+
+static DEFINE_SPINLOCK(dn_rt_flush_lock);
+
+void dn_rt_cache_flush(int delay)
+{
+	unsigned long now = jiffies;
+	int user_mode = !in_interrupt();
+
+	if (delay < 0)
+		delay = dn_rt_min_delay;
+
+	spin_lock_bh(&dn_rt_flush_lock);
+
+	if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
+		long tmo = (long)(dn_rt_deadline - now);
+
+		if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
+			tmo = 0;
+
+		if (delay > tmo)
+			delay = tmo;
+	}
+
+	if (delay <= 0) {
+		spin_unlock_bh(&dn_rt_flush_lock);
+		dn_run_flush(NULL);
+		return;
+	}
+
+	if (dn_rt_deadline == 0)
+		dn_rt_deadline = now + dn_rt_max_delay;
+
+	dn_rt_flush_timer.expires = now + delay;
+	add_timer(&dn_rt_flush_timer);
+	spin_unlock_bh(&dn_rt_flush_lock);
+}
+
+/**
+ * dn_return_short - Return a short packet to its sender
+ * @skb: The packet to return
+ *
+ */
+static int dn_return_short(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb;
+	unsigned char *ptr;
+	__le16 *src;
+	__le16 *dst;
+
+	/* Add back headers */
+	skb_push(skb, skb->data - skb_network_header(skb));
+
+	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
+		return NET_RX_DROP;
+
+	cb = DN_SKB_CB(skb);
+	/* Skip packet length and point to flags */
+	ptr = skb->data + 2;
+	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
+
+	dst = (__le16 *)ptr;
+	ptr += 2;
+	src = (__le16 *)ptr;
+	ptr += 2;
+	*ptr = 0; /* Zero hop count */
+
+	swap(*src, *dst);
+
+	skb->pkt_type = PACKET_OUTGOING;
+	dn_rt_finish_output(skb, NULL, NULL);
+	return NET_RX_SUCCESS;
+}
+
+/**
+ * dn_return_long - Return a long packet to its sender
+ * @skb: The long format packet to return
+ *
+ */
+static int dn_return_long(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb;
+	unsigned char *ptr;
+	unsigned char *src_addr, *dst_addr;
+	unsigned char tmp[ETH_ALEN];
+
+	/* Add back all headers */
+	skb_push(skb, skb->data - skb_network_header(skb));
+
+	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
+		return NET_RX_DROP;
+
+	cb = DN_SKB_CB(skb);
+	/* Ignore packet length and point to flags */
+	ptr = skb->data + 2;
+
+	/* Skip padding */
+	if (*ptr & DN_RT_F_PF) {
+		char padlen = (*ptr & ~DN_RT_F_PF);
+		ptr += padlen;
+	}
+
+	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
+	ptr += 2;
+	dst_addr = ptr;
+	ptr += 8;
+	src_addr = ptr;
+	ptr += 6;
+	*ptr = 0; /* Zero hop count */
+
+	/* Swap source and destination */
+	memcpy(tmp, src_addr, ETH_ALEN);
+	memcpy(src_addr, dst_addr, ETH_ALEN);
+	memcpy(dst_addr, tmp, ETH_ALEN);
+
+	skb->pkt_type = PACKET_OUTGOING;
+	dn_rt_finish_output(skb, dst_addr, src_addr);
+	return NET_RX_SUCCESS;
+}
+
+/**
+ * dn_route_rx_packet - Try and find a route for an incoming packet
+ * @skb: The packet to find a route for
+ *
+ * Returns: result of input function if route is found, error code otherwise
+ */
+static int dn_route_rx_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb;
+	int err;
+
+	if ((err = dn_route_input(skb)) == 0)
+		return dst_input(skb);
+
+	cb = DN_SKB_CB(skb);
+	if (decnet_debug_level & 4) {
+		char *devname = skb->dev ? skb->dev->name : "???";
+
+		printk(KERN_DEBUG
+			"DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
+			(int)cb->rt_flags, devname, skb->len,
+			le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
+			err, skb->pkt_type);
+	}
+
+	if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
+		switch (cb->rt_flags & DN_RT_PKT_MSK) {
+		case DN_RT_PKT_SHORT:
+			return dn_return_short(skb);
+		case DN_RT_PKT_LONG:
+			return dn_return_long(skb);
+		}
+	}
+
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+static int dn_route_rx_long(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	unsigned char *ptr = skb->data;
+
+	if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
+		goto drop_it;
+
+	skb_pull(skb, 20);
+	skb_reset_transport_header(skb);
+
+	/* Destination info */
+	ptr += 2;
+	cb->dst = dn_eth2dn(ptr);
+	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
+		goto drop_it;
+	ptr += 6;
+
+
+	/* Source info */
+	ptr += 2;
+	cb->src = dn_eth2dn(ptr);
+	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
+		goto drop_it;
+	ptr += 6;
+	/* Other junk */
+	ptr++;
+	cb->hops = *ptr++; /* Visit Count */
+
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
+		       &init_net, NULL, skb, skb->dev, NULL,
+		       dn_route_rx_packet);
+
+drop_it:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+
+
+static int dn_route_rx_short(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	unsigned char *ptr = skb->data;
+
+	if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
+		goto drop_it;
+
+	skb_pull(skb, 5);
+	skb_reset_transport_header(skb);
+
+	cb->dst = *(__le16 *)ptr;
+	ptr += 2;
+	cb->src = *(__le16 *)ptr;
+	ptr += 2;
+	cb->hops = *ptr & 0x3f;
+
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
+		       &init_net, NULL, skb, skb->dev, NULL,
+		       dn_route_rx_packet);
+
+drop_it:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+static int dn_route_discard(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	/*
+	 * I know we drop the packet here, but thats considered success in
+	 * this case
+	 */
+	kfree_skb(skb);
+	return NET_RX_SUCCESS;
+}
+
+static int dn_route_ptp_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	dn_dev_hello(skb);
+	dn_neigh_pointopoint_hello(skb);
+	return NET_RX_SUCCESS;
+}
+
+int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct dn_skb_cb *cb;
+	unsigned char flags = 0;
+	__u16 len = le16_to_cpu(*(__le16 *)skb->data);
+	struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
+	unsigned char padlen = 0;
+
+	if (!net_eq(dev_net(dev), &init_net))
+		goto dump_it;
+
+	if (dn == NULL)
+		goto dump_it;
+
+	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
+		goto out;
+
+	if (!pskb_may_pull(skb, 3))
+		goto dump_it;
+
+	skb_pull(skb, 2);
+
+	if (len > skb->len)
+		goto dump_it;
+
+	skb_trim(skb, len);
+
+	flags = *skb->data;
+
+	cb = DN_SKB_CB(skb);
+	cb->stamp = jiffies;
+	cb->iif = dev->ifindex;
+
+	/*
+	 * If we have padding, remove it.
+	 */
+	if (flags & DN_RT_F_PF) {
+		padlen = flags & ~DN_RT_F_PF;
+		if (!pskb_may_pull(skb, padlen + 1))
+			goto dump_it;
+		skb_pull(skb, padlen);
+		flags = *skb->data;
+	}
+
+	skb_reset_network_header(skb);
+
+	/*
+	 * Weed out future version DECnet
+	 */
+	if (flags & DN_RT_F_VER)
+		goto dump_it;
+
+	cb->rt_flags = flags;
+
+	if (decnet_debug_level & 1)
+		printk(KERN_DEBUG
+			"dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
+			(int)flags, (dev) ? dev->name : "???", len, skb->len,
+			padlen);
+
+	if (flags & DN_RT_PKT_CNTL) {
+		if (unlikely(skb_linearize(skb)))
+			goto dump_it;
+
+		switch (flags & DN_RT_CNTL_MSK) {
+		case DN_RT_PKT_INIT:
+			dn_dev_init_pkt(skb);
+			break;
+		case DN_RT_PKT_VERI:
+			dn_dev_veri_pkt(skb);
+			break;
+		}
+
+		if (dn->parms.state != DN_DEV_S_RU)
+			goto dump_it;
+
+		switch (flags & DN_RT_CNTL_MSK) {
+		case DN_RT_PKT_HELO:
+			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
+				       &init_net, NULL, skb, skb->dev, NULL,
+				       dn_route_ptp_hello);
+
+		case DN_RT_PKT_L1RT:
+		case DN_RT_PKT_L2RT:
+			return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
+				       &init_net, NULL, skb, skb->dev, NULL,
+				       dn_route_discard);
+		case DN_RT_PKT_ERTH:
+			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
+				       &init_net, NULL, skb, skb->dev, NULL,
+				       dn_neigh_router_hello);
+
+		case DN_RT_PKT_EEDH:
+			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
+				       &init_net, NULL, skb, skb->dev, NULL,
+				       dn_neigh_endnode_hello);
+		}
+	} else {
+		if (dn->parms.state != DN_DEV_S_RU)
+			goto dump_it;
+
+		skb_pull(skb, 1); /* Pull flags */
+
+		switch (flags & DN_RT_PKT_MSK) {
+		case DN_RT_PKT_LONG:
+			return dn_route_rx_long(skb);
+		case DN_RT_PKT_SHORT:
+			return dn_route_rx_short(skb);
+		}
+	}
+
+dump_it:
+	kfree_skb(skb);
+out:
+	return NET_RX_DROP;
+}
+
+static int dn_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	struct dn_route *rt = (struct dn_route *)dst;
+	struct net_device *dev = dst->dev;
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+
+	int err = -EINVAL;
+
+	if (rt->n == NULL)
+		goto error;
+
+	skb->dev = dev;
+
+	cb->src = rt->rt_saddr;
+	cb->dst = rt->rt_daddr;
+
+	/*
+	 * Always set the Intra-Ethernet bit on all outgoing packets
+	 * originated on this node. Only valid flag from upper layers
+	 * is return-to-sender-requested. Set hop count to 0 too.
+	 */
+	cb->rt_flags &= ~DN_RT_F_RQR;
+	cb->rt_flags |= DN_RT_F_IE;
+	cb->hops = 0;
+
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT,
+		       &init_net, sk, skb, NULL, dev,
+		       dn_to_neigh_output);
+
+error:
+	net_dbg_ratelimited("dn_output: This should not happen\n");
+
+	kfree_skb(skb);
+
+	return err;
+}
+
+static int dn_forward(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct dst_entry *dst = skb_dst(skb);
+	struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
+	struct dn_route *rt;
+	int header_len;
+	struct net_device *dev = skb->dev;
+
+	if (skb->pkt_type != PACKET_HOST)
+		goto drop;
+
+	/* Ensure that we have enough space for headers */
+	rt = (struct dn_route *)skb_dst(skb);
+	header_len = dn_db->use_long ? 21 : 6;
+	if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
+		goto drop;
+
+	/*
+	 * Hop count exceeded.
+	 */
+	if (++cb->hops > 30)
+		goto drop;
+
+	skb->dev = rt->dst.dev;
+
+	/*
+	 * If packet goes out same interface it came in on, then set
+	 * the Intra-Ethernet bit. This has no effect for short
+	 * packets, so we don't need to test for them here.
+	 */
+	cb->rt_flags &= ~DN_RT_F_IE;
+	if (rt->rt_flags & RTCF_DOREDIRECT)
+		cb->rt_flags |= DN_RT_F_IE;
+
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD,
+		       &init_net, NULL, skb, dev, skb->dev,
+		       dn_to_neigh_output);
+
+drop:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+/*
+ * Used to catch bugs. This should never normally get
+ * called.
+ */
+static int dn_rt_bug_out(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+
+	net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
+			    le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
+
+	kfree_skb(skb);
+
+	return NET_RX_DROP;
+}
+
+static int dn_rt_bug(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+
+	net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
+			    le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
+
+	kfree_skb(skb);
+
+	return NET_RX_DROP;
+}
+
+static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
+{
+	return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
+}
+
+static unsigned int dn_dst_mtu(const struct dst_entry *dst)
+{
+	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
+
+	return mtu ? : dst->dev->mtu;
+}
+
+static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
+					     struct sk_buff *skb,
+					     const void *daddr)
+{
+	return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
+}
+
+static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
+{
+	struct dn_fib_info *fi = res->fi;
+	struct net_device *dev = rt->dst.dev;
+	unsigned int mss_metric;
+	struct neighbour *n;
+
+	if (fi) {
+		if (DN_FIB_RES_GW(*res) &&
+		    DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
+			rt->rt_gateway = DN_FIB_RES_GW(*res);
+		dst_init_metrics(&rt->dst, fi->fib_metrics, true);
+	}
+	rt->rt_type = res->type;
+
+	if (dev != NULL && rt->n == NULL) {
+		n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
+		if (IS_ERR(n))
+			return PTR_ERR(n);
+		rt->n = n;
+	}
+
+	if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
+		dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
+	mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
+	if (mss_metric) {
+		unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
+		if (mss_metric > mss)
+			dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
+	}
+	return 0;
+}
+
+static inline int dn_match_addr(__le16 addr1, __le16 addr2)
+{
+	__u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
+	int match = 16;
+	while(tmp) {
+		tmp >>= 1;
+		match--;
+	}
+	return match;
+}
+
+static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
+{
+	__le16 saddr = 0;
+	struct dn_dev *dn_db;
+	struct dn_ifaddr *ifa;
+	int best_match = 0;
+	int ret;
+
+	rcu_read_lock();
+	dn_db = rcu_dereference(dev->dn_ptr);
+	for (ifa = rcu_dereference(dn_db->ifa_list);
+	     ifa != NULL;
+	     ifa = rcu_dereference(ifa->ifa_next)) {
+		if (ifa->ifa_scope > scope)
+			continue;
+		if (!daddr) {
+			saddr = ifa->ifa_local;
+			break;
+		}
+		ret = dn_match_addr(daddr, ifa->ifa_local);
+		if (ret > best_match)
+			saddr = ifa->ifa_local;
+		if (best_match == 0)
+			saddr = ifa->ifa_local;
+	}
+	rcu_read_unlock();
+
+	return saddr;
+}
+
+static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
+{
+	return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
+}
+
+static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
+{
+	__le16 mask = dnet_make_mask(res->prefixlen);
+	return (daddr&~mask)|res->fi->fib_nh->nh_gw;
+}
+
+static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *oldflp, int try_hard)
+{
+	struct flowidn fld = {
+		.daddr = oldflp->daddr,
+		.saddr = oldflp->saddr,
+		.flowidn_scope = RT_SCOPE_UNIVERSE,
+		.flowidn_mark = oldflp->flowidn_mark,
+		.flowidn_iif = LOOPBACK_IFINDEX,
+		.flowidn_oif = oldflp->flowidn_oif,
+	};
+	struct dn_route *rt = NULL;
+	struct net_device *dev_out = NULL, *dev;
+	struct neighbour *neigh = NULL;
+	unsigned int hash;
+	unsigned int flags = 0;
+	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
+	int err;
+	int free_res = 0;
+	__le16 gateway = 0;
+
+	if (decnet_debug_level & 16)
+		printk(KERN_DEBUG
+		       "dn_route_output_slow: dst=%04x src=%04x mark=%d"
+		       " iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
+		       le16_to_cpu(oldflp->saddr),
+		       oldflp->flowidn_mark, LOOPBACK_IFINDEX,
+		       oldflp->flowidn_oif);
+
+	/* If we have an output interface, verify its a DECnet device */
+	if (oldflp->flowidn_oif) {
+		dev_out = dev_get_by_index(&init_net, oldflp->flowidn_oif);
+		err = -ENODEV;
+		if (dev_out && dev_out->dn_ptr == NULL) {
+			dev_put(dev_out);
+			dev_out = NULL;
+		}
+		if (dev_out == NULL)
+			goto out;
+	}
+
+	/* If we have a source address, verify that its a local address */
+	if (oldflp->saddr) {
+		err = -EADDRNOTAVAIL;
+
+		if (dev_out) {
+			if (dn_dev_islocal(dev_out, oldflp->saddr))
+				goto source_ok;
+			dev_put(dev_out);
+			goto out;
+		}
+		rcu_read_lock();
+		for_each_netdev_rcu(&init_net, dev) {
+			if (!dev->dn_ptr)
+				continue;
+			if (!dn_dev_islocal(dev, oldflp->saddr))
+				continue;
+			if ((dev->flags & IFF_LOOPBACK) &&
+			    oldflp->daddr &&
+			    !dn_dev_islocal(dev, oldflp->daddr))
+				continue;
+
+			dev_out = dev;
+			break;
+		}
+		rcu_read_unlock();
+		if (dev_out == NULL)
+			goto out;
+		dev_hold(dev_out);
+source_ok:
+		;
+	}
+
+	/* No destination? Assume its local */
+	if (!fld.daddr) {
+		fld.daddr = fld.saddr;
+
+		if (dev_out)
+			dev_put(dev_out);
+		err = -EINVAL;
+		dev_out = init_net.loopback_dev;
+		if (!dev_out->dn_ptr)
+			goto out;
+		err = -EADDRNOTAVAIL;
+		dev_hold(dev_out);
+		if (!fld.daddr) {
+			fld.daddr =
+			fld.saddr = dnet_select_source(dev_out, 0,
+						       RT_SCOPE_HOST);
+			if (!fld.daddr)
+				goto out;
+		}
+		fld.flowidn_oif = LOOPBACK_IFINDEX;
+		res.type = RTN_LOCAL;
+		goto make_route;
+	}
+
+	if (decnet_debug_level & 16)
+		printk(KERN_DEBUG
+		       "dn_route_output_slow: initial checks complete."
+		       " dst=%04x src=%04x oif=%d try_hard=%d\n",
+		       le16_to_cpu(fld.daddr), le16_to_cpu(fld.saddr),
+		       fld.flowidn_oif, try_hard);
+
+	/*
+	 * N.B. If the kernel is compiled without router support then
+	 * dn_fib_lookup() will evaluate to non-zero so this if () block
+	 * will always be executed.
+	 */
+	err = -ESRCH;
+	if (try_hard || (err = dn_fib_lookup(&fld, &res)) != 0) {
+		struct dn_dev *dn_db;
+		if (err != -ESRCH)
+			goto out;
+		/*
+		 * Here the fallback is basically the standard algorithm for
+		 * routing in endnodes which is described in the DECnet routing
+		 * docs
+		 *
+		 * If we are not trying hard, look in neighbour cache.
+		 * The result is tested to ensure that if a specific output
+		 * device/source address was requested, then we honour that
+		 * here
+		 */
+		if (!try_hard) {
+			neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fld.daddr);
+			if (neigh) {
+				if ((oldflp->flowidn_oif &&
+				    (neigh->dev->ifindex != oldflp->flowidn_oif)) ||
+				    (oldflp->saddr &&
+				    (!dn_dev_islocal(neigh->dev,
+						     oldflp->saddr)))) {
+					neigh_release(neigh);
+					neigh = NULL;
+				} else {
+					if (dev_out)
+						dev_put(dev_out);
+					if (dn_dev_islocal(neigh->dev, fld.daddr)) {
+						dev_out = init_net.loopback_dev;
+						res.type = RTN_LOCAL;
+					} else {
+						dev_out = neigh->dev;
+					}
+					dev_hold(dev_out);
+					goto select_source;
+				}
+			}
+		}
+
+		/* Not there? Perhaps its a local address */
+		if (dev_out == NULL)
+			dev_out = dn_dev_get_default();
+		err = -ENODEV;
+		if (dev_out == NULL)
+			goto out;
+		dn_db = rcu_dereference_raw(dev_out->dn_ptr);
+		if (!dn_db)
+			goto e_inval;
+		/* Possible improvement - check all devices for local addr */
+		if (dn_dev_islocal(dev_out, fld.daddr)) {
+			dev_put(dev_out);
+			dev_out = init_net.loopback_dev;
+			dev_hold(dev_out);
+			res.type = RTN_LOCAL;
+			goto select_source;
+		}
+		/* Not local either.... try sending it to the default router */
+		neigh = neigh_clone(dn_db->router);
+		BUG_ON(neigh && neigh->dev != dev_out);
+
+		/* Ok then, we assume its directly connected and move on */
+select_source:
+		if (neigh)
+			gateway = ((struct dn_neigh *)neigh)->addr;
+		if (gateway == 0)
+			gateway = fld.daddr;
+		if (fld.saddr == 0) {
+			fld.saddr = dnet_select_source(dev_out, gateway,
+						       res.type == RTN_LOCAL ?
+						       RT_SCOPE_HOST :
+						       RT_SCOPE_LINK);
+			if (fld.saddr == 0 && res.type != RTN_LOCAL)
+				goto e_addr;
+		}
+		fld.flowidn_oif = dev_out->ifindex;
+		goto make_route;
+	}
+	free_res = 1;
+
+	if (res.type == RTN_NAT)
+		goto e_inval;
+
+	if (res.type == RTN_LOCAL) {
+		if (!fld.saddr)
+			fld.saddr = fld.daddr;
+		if (dev_out)
+			dev_put(dev_out);
+		dev_out = init_net.loopback_dev;
+		dev_hold(dev_out);
+		if (!dev_out->dn_ptr)
+			goto e_inval;
+		fld.flowidn_oif = dev_out->ifindex;
+		if (res.fi)
+			dn_fib_info_put(res.fi);
+		res.fi = NULL;
+		goto make_route;
+	}
+
+	if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
+		dn_fib_select_multipath(&fld, &res);
+
+	/*
+	 * We could add some logic to deal with default routes here and
+	 * get rid of some of the special casing above.
+	 */
+
+	if (!fld.saddr)
+		fld.saddr = DN_FIB_RES_PREFSRC(res);
+
+	if (dev_out)
+		dev_put(dev_out);
+	dev_out = DN_FIB_RES_DEV(res);
+	dev_hold(dev_out);
+	fld.flowidn_oif = dev_out->ifindex;
+	gateway = DN_FIB_RES_GW(res);
+
+make_route:
+	if (dev_out->flags & IFF_LOOPBACK)
+		flags |= RTCF_LOCAL;
+
+	rt = dst_alloc(&dn_dst_ops, dev_out, 0, DST_OBSOLETE_NONE, DST_HOST);
+	if (rt == NULL)
+		goto e_nobufs;
+
+	rt->dn_next = NULL;
+	memset(&rt->fld, 0, sizeof(rt->fld));
+	rt->fld.saddr        = oldflp->saddr;
+	rt->fld.daddr        = oldflp->daddr;
+	rt->fld.flowidn_oif  = oldflp->flowidn_oif;
+	rt->fld.flowidn_iif  = 0;
+	rt->fld.flowidn_mark = oldflp->flowidn_mark;
+
+	rt->rt_saddr      = fld.saddr;
+	rt->rt_daddr      = fld.daddr;
+	rt->rt_gateway    = gateway ? gateway : fld.daddr;
+	rt->rt_local_src  = fld.saddr;
+
+	rt->rt_dst_map    = fld.daddr;
+	rt->rt_src_map    = fld.saddr;
+
+	rt->n = neigh;
+	neigh = NULL;
+
+	rt->dst.lastuse = jiffies;
+	rt->dst.output  = dn_output;
+	rt->dst.input   = dn_rt_bug;
+	rt->rt_flags      = flags;
+	if (flags & RTCF_LOCAL)
+		rt->dst.input = dn_nsp_rx;
+
+	err = dn_rt_set_next_hop(rt, &res);
+	if (err)
+		goto e_neighbour;
+
+	hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
+	/* dn_insert_route() increments dst->__refcnt */
+	dn_insert_route(rt, hash, (struct dn_route **)pprt);
+
+done:
+	if (neigh)
+		neigh_release(neigh);
+	if (free_res)
+		dn_fib_res_put(&res);
+	if (dev_out)
+		dev_put(dev_out);
+out:
+	return err;
+
+e_addr:
+	err = -EADDRNOTAVAIL;
+	goto done;
+e_inval:
+	err = -EINVAL;
+	goto done;
+e_nobufs:
+	err = -ENOBUFS;
+	goto done;
+e_neighbour:
+	dst_release_immediate(&rt->dst);
+	goto e_nobufs;
+}
+
+
+/*
+ * N.B. The flags may be moved into the flowi at some future stage.
+ */
+static int __dn_route_output_key(struct dst_entry **pprt, const struct flowidn *flp, int flags)
+{
+	unsigned int hash = dn_hash(flp->saddr, flp->daddr);
+	struct dn_route *rt = NULL;
+
+	if (!(flags & MSG_TRYHARD)) {
+		rcu_read_lock_bh();
+		for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
+			rt = rcu_dereference_bh(rt->dn_next)) {
+			if ((flp->daddr == rt->fld.daddr) &&
+			    (flp->saddr == rt->fld.saddr) &&
+			    (flp->flowidn_mark == rt->fld.flowidn_mark) &&
+			    dn_is_output_route(rt) &&
+			    (rt->fld.flowidn_oif == flp->flowidn_oif)) {
+				dst_hold_and_use(&rt->dst, jiffies);
+				rcu_read_unlock_bh();
+				*pprt = &rt->dst;
+				return 0;
+			}
+		}
+		rcu_read_unlock_bh();
+	}
+
+	return dn_route_output_slow(pprt, flp, flags);
+}
+
+static int dn_route_output_key(struct dst_entry **pprt, struct flowidn *flp, int flags)
+{
+	int err;
+
+	err = __dn_route_output_key(pprt, flp, flags);
+	if (err == 0 && flp->flowidn_proto) {
+		*pprt = xfrm_lookup(&init_net, *pprt,
+				    flowidn_to_flowi(flp), NULL, 0);
+		if (IS_ERR(*pprt)) {
+			err = PTR_ERR(*pprt);
+			*pprt = NULL;
+		}
+	}
+	return err;
+}
+
+int dn_route_output_sock(struct dst_entry __rcu **pprt, struct flowidn *fl, struct sock *sk, int flags)
+{
+	int err;
+
+	err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
+	if (err == 0 && fl->flowidn_proto) {
+		*pprt = xfrm_lookup(&init_net, *pprt,
+				    flowidn_to_flowi(fl), sk, 0);
+		if (IS_ERR(*pprt)) {
+			err = PTR_ERR(*pprt);
+			*pprt = NULL;
+		}
+	}
+	return err;
+}
+
+static int dn_route_input_slow(struct sk_buff *skb)
+{
+	struct dn_route *rt = NULL;
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	struct net_device *in_dev = skb->dev;
+	struct net_device *out_dev = NULL;
+	struct dn_dev *dn_db;
+	struct neighbour *neigh = NULL;
+	unsigned int hash;
+	int flags = 0;
+	__le16 gateway = 0;
+	__le16 local_src = 0;
+	struct flowidn fld = {
+		.daddr = cb->dst,
+		.saddr = cb->src,
+		.flowidn_scope = RT_SCOPE_UNIVERSE,
+		.flowidn_mark = skb->mark,
+		.flowidn_iif = skb->dev->ifindex,
+	};
+	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
+	int err = -EINVAL;
+	int free_res = 0;
+
+	dev_hold(in_dev);
+
+	if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
+		goto out;
+
+	/* Zero source addresses are not allowed */
+	if (fld.saddr == 0)
+		goto out;
+
+	/*
+	 * In this case we've just received a packet from a source
+	 * outside ourselves pretending to come from us. We don't
+	 * allow it any further to prevent routing loops, spoofing and
+	 * other nasties. Loopback packets already have the dst attached
+	 * so this only affects packets which have originated elsewhere.
+	 */
+	err  = -ENOTUNIQ;
+	if (dn_dev_islocal(in_dev, cb->src))
+		goto out;
+
+	err = dn_fib_lookup(&fld, &res);
+	if (err) {
+		if (err != -ESRCH)
+			goto out;
+		/*
+		 * Is the destination us ?
+		 */
+		if (!dn_dev_islocal(in_dev, cb->dst))
+			goto e_inval;
+
+		res.type = RTN_LOCAL;
+	} else {
+		__le16 src_map = fld.saddr;
+		free_res = 1;
+
+		out_dev = DN_FIB_RES_DEV(res);
+		if (out_dev == NULL) {
+			net_crit_ratelimited("Bug in dn_route_input_slow() No output device\n");
+			goto e_inval;
+		}
+		dev_hold(out_dev);
+
+		if (res.r)
+			src_map = fld.saddr; /* no NAT support for now */
+
+		gateway = DN_FIB_RES_GW(res);
+		if (res.type == RTN_NAT) {
+			fld.daddr = dn_fib_rules_map_destination(fld.daddr, &res);
+			dn_fib_res_put(&res);
+			free_res = 0;
+			if (dn_fib_lookup(&fld, &res))
+				goto e_inval;
+			free_res = 1;
+			if (res.type != RTN_UNICAST)
+				goto e_inval;
+			flags |= RTCF_DNAT;
+			gateway = fld.daddr;
+		}
+		fld.saddr = src_map;
+	}
+
+	switch(res.type) {
+	case RTN_UNICAST:
+		/*
+		 * Forwarding check here, we only check for forwarding
+		 * being turned off, if you want to only forward intra
+		 * area, its up to you to set the routing tables up
+		 * correctly.
+		 */
+		if (dn_db->parms.forwarding == 0)
+			goto e_inval;
+
+		if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
+			dn_fib_select_multipath(&fld, &res);
+
+		/*
+		 * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
+		 * flag as a hint to set the intra-ethernet bit when
+		 * forwarding. If we've got NAT in operation, we don't do
+		 * this optimisation.
+		 */
+		if (out_dev == in_dev && !(flags & RTCF_NAT))
+			flags |= RTCF_DOREDIRECT;
+
+		local_src = DN_FIB_RES_PREFSRC(res);
+
+	case RTN_BLACKHOLE:
+	case RTN_UNREACHABLE:
+		break;
+	case RTN_LOCAL:
+		flags |= RTCF_LOCAL;
+		fld.saddr = cb->dst;
+		fld.daddr = cb->src;
+
+		/* Routing tables gave us a gateway */
+		if (gateway)
+			goto make_route;
+
+		/* Packet was intra-ethernet, so we know its on-link */
+		if (cb->rt_flags & DN_RT_F_IE) {
+			gateway = cb->src;
+			goto make_route;
+		}
+
+		/* Use the default router if there is one */
+		neigh = neigh_clone(dn_db->router);
+		if (neigh) {
+			gateway = ((struct dn_neigh *)neigh)->addr;
+			goto make_route;
+		}
+
+		/* Close eyes and pray */
+		gateway = cb->src;
+		goto make_route;
+	default:
+		goto e_inval;
+	}
+
+make_route:
+	rt = dst_alloc(&dn_dst_ops, out_dev, 1, DST_OBSOLETE_NONE, DST_HOST);
+	if (rt == NULL)
+		goto e_nobufs;
+
+	rt->dn_next = NULL;
+	memset(&rt->fld, 0, sizeof(rt->fld));
+	rt->rt_saddr      = fld.saddr;
+	rt->rt_daddr      = fld.daddr;
+	rt->rt_gateway    = fld.daddr;
+	if (gateway)
+		rt->rt_gateway = gateway;
+	rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
+
+	rt->rt_dst_map    = fld.daddr;
+	rt->rt_src_map    = fld.saddr;
+
+	rt->fld.saddr        = cb->src;
+	rt->fld.daddr        = cb->dst;
+	rt->fld.flowidn_oif  = 0;
+	rt->fld.flowidn_iif  = in_dev->ifindex;
+	rt->fld.flowidn_mark = fld.flowidn_mark;
+
+	rt->n = neigh;
+	rt->dst.lastuse = jiffies;
+	rt->dst.output = dn_rt_bug_out;
+	switch (res.type) {
+	case RTN_UNICAST:
+		rt->dst.input = dn_forward;
+		break;
+	case RTN_LOCAL:
+		rt->dst.output = dn_output;
+		rt->dst.input = dn_nsp_rx;
+		rt->dst.dev = in_dev;
+		flags |= RTCF_LOCAL;
+		break;
+	default:
+	case RTN_UNREACHABLE:
+	case RTN_BLACKHOLE:
+		rt->dst.input = dst_discard;
+	}
+	rt->rt_flags = flags;
+
+	err = dn_rt_set_next_hop(rt, &res);
+	if (err)
+		goto e_neighbour;
+
+	hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
+	/* dn_insert_route() increments dst->__refcnt */
+	dn_insert_route(rt, hash, &rt);
+	skb_dst_set(skb, &rt->dst);
+
+done:
+	if (neigh)
+		neigh_release(neigh);
+	if (free_res)
+		dn_fib_res_put(&res);
+	dev_put(in_dev);
+	if (out_dev)
+		dev_put(out_dev);
+out:
+	return err;
+
+e_inval:
+	err = -EINVAL;
+	goto done;
+
+e_nobufs:
+	err = -ENOBUFS;
+	goto done;
+
+e_neighbour:
+	dst_release_immediate(&rt->dst);
+	goto done;
+}
+
+static int dn_route_input(struct sk_buff *skb)
+{
+	struct dn_route *rt;
+	struct dn_skb_cb *cb = DN_SKB_CB(skb);
+	unsigned int hash = dn_hash(cb->src, cb->dst);
+
+	if (skb_dst(skb))
+		return 0;
+
+	rcu_read_lock();
+	for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
+	    rt = rcu_dereference(rt->dn_next)) {
+		if ((rt->fld.saddr == cb->src) &&
+		    (rt->fld.daddr == cb->dst) &&
+		    (rt->fld.flowidn_oif == 0) &&
+		    (rt->fld.flowidn_mark == skb->mark) &&
+		    (rt->fld.flowidn_iif == cb->iif)) {
+			dst_hold_and_use(&rt->dst, jiffies);
+			rcu_read_unlock();
+			skb_dst_set(skb, (struct dst_entry *)rt);
+			return 0;
+		}
+	}
+	rcu_read_unlock();
+
+	return dn_route_input_slow(skb);
+}
+
+static int dn_rt_fill_info(struct sk_buff *skb, u32 portid, u32 seq,
+			   int event, int nowait, unsigned int flags)
+{
+	struct dn_route *rt = (struct dn_route *)skb_dst(skb);
+	struct rtmsg *r;
+	struct nlmsghdr *nlh;
+	long expires;
+
+	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
+	if (!nlh)
+		return -EMSGSIZE;
+
+	r = nlmsg_data(nlh);
+	r->rtm_family = AF_DECnet;
+	r->rtm_dst_len = 16;
+	r->rtm_src_len = 0;
+	r->rtm_tos = 0;
+	r->rtm_table = RT_TABLE_MAIN;
+	r->rtm_type = rt->rt_type;
+	r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
+	r->rtm_scope = RT_SCOPE_UNIVERSE;
+	r->rtm_protocol = RTPROT_UNSPEC;
+
+	if (rt->rt_flags & RTCF_NOTIFY)
+		r->rtm_flags |= RTM_F_NOTIFY;
+
+	if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN) < 0 ||
+	    nla_put_le16(skb, RTA_DST, rt->rt_daddr) < 0)
+		goto errout;
+
+	if (rt->fld.saddr) {
+		r->rtm_src_len = 16;
+		if (nla_put_le16(skb, RTA_SRC, rt->fld.saddr) < 0)
+			goto errout;
+	}
+	if (rt->dst.dev &&
+	    nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex) < 0)
+		goto errout;
+
+	/*
+	 * Note to self - change this if input routes reverse direction when
+	 * they deal only with inputs and not with replies like they do
+	 * currently.
+	 */
+	if (nla_put_le16(skb, RTA_PREFSRC, rt->rt_local_src) < 0)
+		goto errout;
+
+	if (rt->rt_daddr != rt->rt_gateway &&
+	    nla_put_le16(skb, RTA_GATEWAY, rt->rt_gateway) < 0)
+		goto errout;
+
+	if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
+		goto errout;
+
+	expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
+	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires,
+			       rt->dst.error) < 0)
+		goto errout;
+
+	if (dn_is_input_route(rt) &&
+	    nla_put_u32(skb, RTA_IIF, rt->fld.flowidn_iif) < 0)
+		goto errout;
+
+	nlmsg_end(skb, nlh);
+	return 0;
+
+errout:
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
+}
+
+const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
+	[RTA_DST]		= { .type = NLA_U16 },
+	[RTA_SRC]		= { .type = NLA_U16 },
+	[RTA_IIF]		= { .type = NLA_U32 },
+	[RTA_OIF]		= { .type = NLA_U32 },
+	[RTA_GATEWAY]		= { .type = NLA_U16 },
+	[RTA_PRIORITY]		= { .type = NLA_U32 },
+	[RTA_PREFSRC]		= { .type = NLA_U16 },
+	[RTA_METRICS]		= { .type = NLA_NESTED },
+	[RTA_MULTIPATH]		= { .type = NLA_NESTED },
+	[RTA_TABLE]		= { .type = NLA_U32 },
+	[RTA_MARK]		= { .type = NLA_U32 },
+};
+
+/*
+ * This is called by both endnodes and routers now.
+ */
+static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
+			     struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(in_skb->sk);
+	struct rtmsg *rtm = nlmsg_data(nlh);
+	struct dn_route *rt = NULL;
+	struct dn_skb_cb *cb;
+	int err;
+	struct sk_buff *skb;
+	struct flowidn fld;
+	struct nlattr *tb[RTA_MAX+1];
+
+	if (!net_eq(net, &init_net))
+		return -EINVAL;
+
+	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_dn_policy,
+			  extack);
+	if (err < 0)
+		return err;
+
+	memset(&fld, 0, sizeof(fld));
+	fld.flowidn_proto = DNPROTO_NSP;
+
+	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (skb == NULL)
+		return -ENOBUFS;
+	skb_reset_mac_header(skb);
+	cb = DN_SKB_CB(skb);
+
+	if (tb[RTA_SRC])
+		fld.saddr = nla_get_le16(tb[RTA_SRC]);
+
+	if (tb[RTA_DST])
+		fld.daddr = nla_get_le16(tb[RTA_DST]);
+
+	if (tb[RTA_IIF])
+		fld.flowidn_iif = nla_get_u32(tb[RTA_IIF]);
+
+	if (fld.flowidn_iif) {
+		struct net_device *dev;
+		dev = __dev_get_by_index(&init_net, fld.flowidn_iif);
+		if (!dev || !dev->dn_ptr) {
+			kfree_skb(skb);
+			return -ENODEV;
+		}
+		skb->protocol = htons(ETH_P_DNA_RT);
+		skb->dev = dev;
+		cb->src = fld.saddr;
+		cb->dst = fld.daddr;
+		local_bh_disable();
+		err = dn_route_input(skb);
+		local_bh_enable();
+		memset(cb, 0, sizeof(struct dn_skb_cb));
+		rt = (struct dn_route *)skb_dst(skb);
+		if (!err && -rt->dst.error)
+			err = rt->dst.error;
+	} else {
+		if (tb[RTA_OIF])
+			fld.flowidn_oif = nla_get_u32(tb[RTA_OIF]);
+
+		err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
+	}
+
+	skb->dev = NULL;
+	if (err)
+		goto out_free;
+	skb_dst_set(skb, &rt->dst);
+	if (rtm->rtm_flags & RTM_F_NOTIFY)
+		rt->rt_flags |= RTCF_NOTIFY;
+
+	err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
+	if (err < 0) {
+		err = -EMSGSIZE;
+		goto out_free;
+	}
+
+	return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).portid);
+
+out_free:
+	kfree_skb(skb);
+	return err;
+}
+
+/*
+ * For routers, this is called from dn_fib_dump, but for endnodes its
+ * called directly from the rtnetlink dispatch table.
+ */
+int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	struct dn_route *rt;
+	int h, s_h;
+	int idx, s_idx;
+	struct rtmsg *rtm;
+
+	if (!net_eq(net, &init_net))
+		return 0;
+
+	if (nlmsg_len(cb->nlh) < sizeof(struct rtmsg))
+		return -EINVAL;
+
+	rtm = nlmsg_data(cb->nlh);
+	if (!(rtm->rtm_flags & RTM_F_CLONED))
+		return 0;
+
+	s_h = cb->args[0];
+	s_idx = idx = cb->args[1];
+	for(h = 0; h <= dn_rt_hash_mask; h++) {
+		if (h < s_h)
+			continue;
+		if (h > s_h)
+			s_idx = 0;
+		rcu_read_lock_bh();
+		for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
+			rt;
+			rt = rcu_dereference_bh(rt->dn_next), idx++) {
+			if (idx < s_idx)
+				continue;
+			skb_dst_set(skb, dst_clone(&rt->dst));
+			if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).portid,
+					cb->nlh->nlmsg_seq, RTM_NEWROUTE,
+					1, NLM_F_MULTI) < 0) {
+				skb_dst_drop(skb);
+				rcu_read_unlock_bh();
+				goto done;
+			}
+			skb_dst_drop(skb);
+		}
+		rcu_read_unlock_bh();
+	}
+
+done:
+	cb->args[0] = h;
+	cb->args[1] = idx;
+	return skb->len;
+}
+
+#ifdef CONFIG_PROC_FS
+struct dn_rt_cache_iter_state {
+	int bucket;
+};
+
+static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
+{
+	struct dn_route *rt = NULL;
+	struct dn_rt_cache_iter_state *s = seq->private;
+
+	for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
+		rcu_read_lock_bh();
+		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
+		if (rt)
+			break;
+		rcu_read_unlock_bh();
+	}
+	return rt;
+}
+
+static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
+{
+	struct dn_rt_cache_iter_state *s = seq->private;
+
+	rt = rcu_dereference_bh(rt->dn_next);
+	while (!rt) {
+		rcu_read_unlock_bh();
+		if (--s->bucket < 0)
+			break;
+		rcu_read_lock_bh();
+		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
+	}
+	return rt;
+}
+
+static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct dn_route *rt = dn_rt_cache_get_first(seq);
+
+	if (rt) {
+		while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
+			--*pos;
+	}
+	return *pos ? NULL : rt;
+}
+
+static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct dn_route *rt = dn_rt_cache_get_next(seq, v);
+	++*pos;
+	return rt;
+}
+
+static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
+{
+	if (v)
+		rcu_read_unlock_bh();
+}
+
+static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
+{
+	struct dn_route *rt = v;
+	char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
+
+	seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
+		   rt->dst.dev ? rt->dst.dev->name : "*",
+		   dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
+		   dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
+		   atomic_read(&rt->dst.__refcnt),
+		   rt->dst.__use, 0);
+	return 0;
+}
+
+static const struct seq_operations dn_rt_cache_seq_ops = {
+	.start	= dn_rt_cache_seq_start,
+	.next	= dn_rt_cache_seq_next,
+	.stop	= dn_rt_cache_seq_stop,
+	.show	= dn_rt_cache_seq_show,
+};
+#endif /* CONFIG_PROC_FS */
+
+void __init dn_route_init(void)
+{
+	int i, goal, order;
+
+	dn_dst_ops.kmem_cachep =
+		kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
+				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+	dst_entries_init(&dn_dst_ops);
+	timer_setup(&dn_route_timer, dn_dst_check_expire, 0);
+	dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
+	add_timer(&dn_route_timer);
+
+	goal = totalram_pages >> (26 - PAGE_SHIFT);
+
+	for(order = 0; (1UL << order) < goal; order++)
+		/* NOTHING */;
+
+	/*
+	 * Only want 1024 entries max, since the table is very, very unlikely
+	 * to be larger than that.
+	 */
+	while(order && ((((1UL << order) * PAGE_SIZE) /
+				sizeof(struct dn_rt_hash_bucket)) >= 2048))
+		order--;
+
+	do {
+		dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
+			sizeof(struct dn_rt_hash_bucket);
+		while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
+			dn_rt_hash_mask--;
+		dn_rt_hash_table = (struct dn_rt_hash_bucket *)
+			__get_free_pages(GFP_ATOMIC, order);
+	} while (dn_rt_hash_table == NULL && --order > 0);
+
+	if (!dn_rt_hash_table)
+		panic("Failed to allocate DECnet route cache hash table\n");
+
+	printk(KERN_INFO
+		"DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
+		dn_rt_hash_mask,
+		(long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
+
+	dn_rt_hash_mask--;
+	for(i = 0; i <= dn_rt_hash_mask; i++) {
+		spin_lock_init(&dn_rt_hash_table[i].lock);
+		dn_rt_hash_table[i].chain = NULL;
+	}
+
+	dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
+
+	proc_create_seq_private("decnet_cache", 0444, init_net.proc_net,
+			&dn_rt_cache_seq_ops,
+			sizeof(struct dn_rt_cache_iter_state), NULL);
+
+#ifdef CONFIG_DECNET_ROUTER
+	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETROUTE,
+			     dn_cache_getroute, dn_fib_dump, 0);
+#else
+	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETROUTE,
+			     dn_cache_getroute, dn_cache_dump, 0);
+#endif
+}
+
+void __exit dn_route_cleanup(void)
+{
+	del_timer(&dn_route_timer);
+	dn_run_flush(NULL);
+
+	remove_proc_entry("decnet_cache", init_net.proc_net);
+	dst_entries_destroy(&dn_dst_ops);
+}
diff --git a/net/decnet/dn_rules.c b/net/decnet/dn_rules.c
new file mode 100644
index 000000000..4a4e3c177
--- /dev/null
+++ b/net/decnet/dn_rules.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Routing Forwarding Information Base (Rules)
+ *
+ * Author:      Steve Whitehouse <SteveW@ACM.org>
+ *              Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c
+ *
+ *
+ * Changes:
+ *              Steve Whitehouse <steve@chygwyn.com>
+ *              Updated for Thomas Graf's generic rules
+ *
+ */
+#include <linux/net.h>
+#include <linux/init.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/netdevice.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
+#include <linux/export.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/flow.h>
+#include <net/fib_rules.h>
+#include <net/dn.h>
+#include <net/dn_fib.h>
+#include <net/dn_neigh.h>
+#include <net/dn_dev.h>
+#include <net/dn_route.h>
+
+static struct fib_rules_ops *dn_fib_rules_ops;
+
+struct dn_fib_rule
+{
+	struct fib_rule		common;
+	unsigned char		dst_len;
+	unsigned char		src_len;
+	__le16			src;
+	__le16			srcmask;
+	__le16			dst;
+	__le16			dstmask;
+	__le16			srcmap;
+	u8			flags;
+};
+
+
+int dn_fib_lookup(struct flowidn *flp, struct dn_fib_res *res)
+{
+	struct fib_lookup_arg arg = {
+		.result = res,
+	};
+	int err;
+
+	err = fib_rules_lookup(dn_fib_rules_ops,
+			       flowidn_to_flowi(flp), 0, &arg);
+	res->r = arg.rule;
+
+	return err;
+}
+
+static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
+			      int flags, struct fib_lookup_arg *arg)
+{
+	struct flowidn *fld = &flp->u.dn;
+	int err = -EAGAIN;
+	struct dn_fib_table *tbl;
+
+	switch(rule->action) {
+	case FR_ACT_TO_TBL:
+		break;
+
+	case FR_ACT_UNREACHABLE:
+		err = -ENETUNREACH;
+		goto errout;
+
+	case FR_ACT_PROHIBIT:
+		err = -EACCES;
+		goto errout;
+
+	case FR_ACT_BLACKHOLE:
+	default:
+		err = -EINVAL;
+		goto errout;
+	}
+
+	tbl = dn_fib_get_table(rule->table, 0);
+	if (tbl == NULL)
+		goto errout;
+
+	err = tbl->lookup(tbl, fld, (struct dn_fib_res *)arg->result);
+	if (err > 0)
+		err = -EAGAIN;
+errout:
+	return err;
+}
+
+static const struct nla_policy dn_fib_rule_policy[FRA_MAX+1] = {
+	FRA_GENERIC_POLICY,
+};
+
+static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
+{
+	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
+	struct flowidn *fld = &fl->u.dn;
+	__le16 daddr = fld->daddr;
+	__le16 saddr = fld->saddr;
+
+	if (((saddr ^ r->src) & r->srcmask) ||
+	    ((daddr ^ r->dst) & r->dstmask))
+		return 0;
+
+	return 1;
+}
+
+static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
+				 struct fib_rule_hdr *frh,
+				 struct nlattr **tb,
+				 struct netlink_ext_ack *extack)
+{
+	int err = -EINVAL;
+	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
+
+	if (frh->tos) {
+		NL_SET_ERR_MSG(extack, "Invalid tos value");
+		goto  errout;
+	}
+
+	if (rule->table == RT_TABLE_UNSPEC) {
+		if (rule->action == FR_ACT_TO_TBL) {
+			struct dn_fib_table *table;
+
+			table = dn_fib_empty_table();
+			if (table == NULL) {
+				err = -ENOBUFS;
+				goto errout;
+			}
+
+			rule->table = table->n;
+		}
+	}
+
+	if (frh->src_len)
+		r->src = nla_get_le16(tb[FRA_SRC]);
+
+	if (frh->dst_len)
+		r->dst = nla_get_le16(tb[FRA_DST]);
+
+	r->src_len = frh->src_len;
+	r->srcmask = dnet_make_mask(r->src_len);
+	r->dst_len = frh->dst_len;
+	r->dstmask = dnet_make_mask(r->dst_len);
+	err = 0;
+errout:
+	return err;
+}
+
+static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
+			       struct nlattr **tb)
+{
+	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
+
+	if (frh->src_len && (r->src_len != frh->src_len))
+		return 0;
+
+	if (frh->dst_len && (r->dst_len != frh->dst_len))
+		return 0;
+
+	if (frh->src_len && (r->src != nla_get_le16(tb[FRA_SRC])))
+		return 0;
+
+	if (frh->dst_len && (r->dst != nla_get_le16(tb[FRA_DST])))
+		return 0;
+
+	return 1;
+}
+
+unsigned int dnet_addr_type(__le16 addr)
+{
+	struct flowidn fld = { .daddr = addr };
+	struct dn_fib_res res;
+	unsigned int ret = RTN_UNICAST;
+	struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
+
+	res.r = NULL;
+
+	if (tb) {
+		if (!tb->lookup(tb, &fld, &res)) {
+			ret = res.type;
+			dn_fib_res_put(&res);
+		}
+	}
+	return ret;
+}
+
+static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
+			    struct fib_rule_hdr *frh)
+{
+	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
+
+	frh->dst_len = r->dst_len;
+	frh->src_len = r->src_len;
+	frh->tos = 0;
+
+	if ((r->dst_len &&
+	     nla_put_le16(skb, FRA_DST, r->dst)) ||
+	    (r->src_len &&
+	     nla_put_le16(skb, FRA_SRC, r->src)))
+		goto nla_put_failure;
+	return 0;
+
+nla_put_failure:
+	return -ENOBUFS;
+}
+
+static void dn_fib_rule_flush_cache(struct fib_rules_ops *ops)
+{
+	dn_rt_cache_flush(-1);
+}
+
+static const struct fib_rules_ops __net_initconst dn_fib_rules_ops_template = {
+	.family		= AF_DECnet,
+	.rule_size	= sizeof(struct dn_fib_rule),
+	.addr_size	= sizeof(u16),
+	.action		= dn_fib_rule_action,
+	.match		= dn_fib_rule_match,
+	.configure	= dn_fib_rule_configure,
+	.compare	= dn_fib_rule_compare,
+	.fill		= dn_fib_rule_fill,
+	.flush_cache	= dn_fib_rule_flush_cache,
+	.nlgroup	= RTNLGRP_DECnet_RULE,
+	.policy		= dn_fib_rule_policy,
+	.owner		= THIS_MODULE,
+	.fro_net	= &init_net,
+};
+
+void __init dn_fib_rules_init(void)
+{
+	dn_fib_rules_ops =
+		fib_rules_register(&dn_fib_rules_ops_template, &init_net);
+	BUG_ON(IS_ERR(dn_fib_rules_ops));
+	BUG_ON(fib_default_rule_add(dn_fib_rules_ops, 0x7fff,
+			            RT_TABLE_MAIN, 0));
+}
+
+void __exit dn_fib_rules_cleanup(void)
+{
+	rtnl_lock();
+	fib_rules_unregister(dn_fib_rules_ops);
+	rtnl_unlock();
+	rcu_barrier();
+}
diff --git a/net/decnet/dn_table.c b/net/decnet/dn_table.c
new file mode 100644
index 000000000..f0710b5d0
--- /dev/null
+++ b/net/decnet/dn_table.c
@@ -0,0 +1,928 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Routing Forwarding Information Base (Routing Tables)
+ *
+ * Author:      Steve Whitehouse <SteveW@ACM.org>
+ *              Mostly copied from the IPv4 routing code
+ *
+ *
+ * Changes:
+ *
+ */
+#include <linux/string.h>
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/slab.h>
+#include <linux/sockios.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/proc_fs.h>
+#include <linux/netdevice.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <linux/atomic.h>
+#include <linux/uaccess.h>
+#include <linux/route.h> /* RTF_xxx */
+#include <net/neighbour.h>
+#include <net/netlink.h>
+#include <net/tcp.h>
+#include <net/dst.h>
+#include <net/flow.h>
+#include <net/fib_rules.h>
+#include <net/dn.h>
+#include <net/dn_route.h>
+#include <net/dn_fib.h>
+#include <net/dn_neigh.h>
+#include <net/dn_dev.h>
+
+struct dn_zone
+{
+	struct dn_zone		*dz_next;
+	struct dn_fib_node 	**dz_hash;
+	int			dz_nent;
+	int			dz_divisor;
+	u32			dz_hashmask;
+#define DZ_HASHMASK(dz)	((dz)->dz_hashmask)
+	int			dz_order;
+	__le16			dz_mask;
+#define DZ_MASK(dz)	((dz)->dz_mask)
+};
+
+struct dn_hash
+{
+	struct dn_zone	*dh_zones[17];
+	struct dn_zone	*dh_zone_list;
+};
+
+#define dz_key_0(key)		((key).datum = 0)
+
+#define for_nexthops(fi) { int nhsel; const struct dn_fib_nh *nh;\
+	for(nhsel = 0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)
+
+#define endfor_nexthops(fi) }
+
+#define DN_MAX_DIVISOR 1024
+#define DN_S_ZOMBIE 1
+#define DN_S_ACCESSED 2
+
+#define DN_FIB_SCAN(f, fp) \
+for( ; ((f) = *(fp)) != NULL; (fp) = &(f)->fn_next)
+
+#define DN_FIB_SCAN_KEY(f, fp, key) \
+for( ; ((f) = *(fp)) != NULL && dn_key_eq((f)->fn_key, (key)); (fp) = &(f)->fn_next)
+
+#define RT_TABLE_MIN 1
+#define DN_FIB_TABLE_HASHSZ 256
+static struct hlist_head dn_fib_table_hash[DN_FIB_TABLE_HASHSZ];
+static DEFINE_RWLOCK(dn_fib_tables_lock);
+
+static struct kmem_cache *dn_hash_kmem __read_mostly;
+static int dn_fib_hash_zombies;
+
+static inline dn_fib_idx_t dn_hash(dn_fib_key_t key, struct dn_zone *dz)
+{
+	u16 h = le16_to_cpu(key.datum)>>(16 - dz->dz_order);
+	h ^= (h >> 10);
+	h ^= (h >> 6);
+	h &= DZ_HASHMASK(dz);
+	return *(dn_fib_idx_t *)&h;
+}
+
+static inline dn_fib_key_t dz_key(__le16 dst, struct dn_zone *dz)
+{
+	dn_fib_key_t k;
+	k.datum = dst & DZ_MASK(dz);
+	return k;
+}
+
+static inline struct dn_fib_node **dn_chain_p(dn_fib_key_t key, struct dn_zone *dz)
+{
+	return &dz->dz_hash[dn_hash(key, dz).datum];
+}
+
+static inline struct dn_fib_node *dz_chain(dn_fib_key_t key, struct dn_zone *dz)
+{
+	return dz->dz_hash[dn_hash(key, dz).datum];
+}
+
+static inline int dn_key_eq(dn_fib_key_t a, dn_fib_key_t b)
+{
+	return a.datum == b.datum;
+}
+
+static inline int dn_key_leq(dn_fib_key_t a, dn_fib_key_t b)
+{
+	return a.datum <= b.datum;
+}
+
+static inline void dn_rebuild_zone(struct dn_zone *dz,
+				   struct dn_fib_node **old_ht,
+				   int old_divisor)
+{
+	struct dn_fib_node *f, **fp, *next;
+	int i;
+
+	for(i = 0; i < old_divisor; i++) {
+		for(f = old_ht[i]; f; f = next) {
+			next = f->fn_next;
+			for(fp = dn_chain_p(f->fn_key, dz);
+				*fp && dn_key_leq((*fp)->fn_key, f->fn_key);
+				fp = &(*fp)->fn_next)
+				/* NOTHING */;
+			f->fn_next = *fp;
+			*fp = f;
+		}
+	}
+}
+
+static void dn_rehash_zone(struct dn_zone *dz)
+{
+	struct dn_fib_node **ht, **old_ht;
+	int old_divisor, new_divisor;
+	u32 new_hashmask;
+
+	old_divisor = dz->dz_divisor;
+
+	switch (old_divisor) {
+	case 16:
+		new_divisor = 256;
+		new_hashmask = 0xFF;
+		break;
+	default:
+		printk(KERN_DEBUG "DECnet: dn_rehash_zone: BUG! %d\n",
+		       old_divisor);
+		/* fall through */
+	case 256:
+		new_divisor = 1024;
+		new_hashmask = 0x3FF;
+		break;
+	}
+
+	ht = kcalloc(new_divisor, sizeof(struct dn_fib_node*), GFP_KERNEL);
+	if (ht == NULL)
+		return;
+
+	write_lock_bh(&dn_fib_tables_lock);
+	old_ht = dz->dz_hash;
+	dz->dz_hash = ht;
+	dz->dz_hashmask = new_hashmask;
+	dz->dz_divisor = new_divisor;
+	dn_rebuild_zone(dz, old_ht, old_divisor);
+	write_unlock_bh(&dn_fib_tables_lock);
+	kfree(old_ht);
+}
+
+static void dn_free_node(struct dn_fib_node *f)
+{
+	dn_fib_release_info(DN_FIB_INFO(f));
+	kmem_cache_free(dn_hash_kmem, f);
+}
+
+
+static struct dn_zone *dn_new_zone(struct dn_hash *table, int z)
+{
+	int i;
+	struct dn_zone *dz = kzalloc(sizeof(struct dn_zone), GFP_KERNEL);
+	if (!dz)
+		return NULL;
+
+	if (z) {
+		dz->dz_divisor = 16;
+		dz->dz_hashmask = 0x0F;
+	} else {
+		dz->dz_divisor = 1;
+		dz->dz_hashmask = 0;
+	}
+
+	dz->dz_hash = kcalloc(dz->dz_divisor, sizeof(struct dn_fib_node *), GFP_KERNEL);
+	if (!dz->dz_hash) {
+		kfree(dz);
+		return NULL;
+	}
+
+	dz->dz_order = z;
+	dz->dz_mask = dnet_make_mask(z);
+
+	for(i = z + 1; i <= 16; i++)
+		if (table->dh_zones[i])
+			break;
+
+	write_lock_bh(&dn_fib_tables_lock);
+	if (i>16) {
+		dz->dz_next = table->dh_zone_list;
+		table->dh_zone_list = dz;
+	} else {
+		dz->dz_next = table->dh_zones[i]->dz_next;
+		table->dh_zones[i]->dz_next = dz;
+	}
+	table->dh_zones[z] = dz;
+	write_unlock_bh(&dn_fib_tables_lock);
+	return dz;
+}
+
+
+static int dn_fib_nh_match(struct rtmsg *r, struct nlmsghdr *nlh, struct nlattr *attrs[], struct dn_fib_info *fi)
+{
+	struct rtnexthop *nhp;
+	int nhlen;
+
+	if (attrs[RTA_PRIORITY] &&
+	    nla_get_u32(attrs[RTA_PRIORITY]) != fi->fib_priority)
+		return 1;
+
+	if (attrs[RTA_OIF] || attrs[RTA_GATEWAY]) {
+		if ((!attrs[RTA_OIF] || nla_get_u32(attrs[RTA_OIF]) == fi->fib_nh->nh_oif) &&
+		    (!attrs[RTA_GATEWAY]  || nla_get_le16(attrs[RTA_GATEWAY]) != fi->fib_nh->nh_gw))
+			return 0;
+		return 1;
+	}
+
+	if (!attrs[RTA_MULTIPATH])
+		return 0;
+
+	nhp = nla_data(attrs[RTA_MULTIPATH]);
+	nhlen = nla_len(attrs[RTA_MULTIPATH]);
+
+	for_nexthops(fi) {
+		int attrlen = nhlen - sizeof(struct rtnexthop);
+		__le16 gw;
+
+		if (attrlen < 0 || (nhlen -= nhp->rtnh_len) < 0)
+			return -EINVAL;
+		if (nhp->rtnh_ifindex && nhp->rtnh_ifindex != nh->nh_oif)
+			return 1;
+		if (attrlen) {
+			struct nlattr *gw_attr;
+
+			gw_attr = nla_find((struct nlattr *) (nhp + 1), attrlen, RTA_GATEWAY);
+			gw = gw_attr ? nla_get_le16(gw_attr) : 0;
+
+			if (gw && gw != nh->nh_gw)
+				return 1;
+		}
+		nhp = RTNH_NEXT(nhp);
+	} endfor_nexthops(fi);
+
+	return 0;
+}
+
+static inline size_t dn_fib_nlmsg_size(struct dn_fib_info *fi)
+{
+	size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
+			 + nla_total_size(4) /* RTA_TABLE */
+			 + nla_total_size(2) /* RTA_DST */
+			 + nla_total_size(4) /* RTA_PRIORITY */
+			 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
+
+	/* space for nested metrics */
+	payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
+
+	if (fi->fib_nhs) {
+		/* Also handles the special case fib_nhs == 1 */
+
+		/* each nexthop is packed in an attribute */
+		size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
+
+		/* may contain a gateway attribute */
+		nhsize += nla_total_size(4);
+
+		/* all nexthops are packed in a nested attribute */
+		payload += nla_total_size(fi->fib_nhs * nhsize);
+	}
+
+	return payload;
+}
+
+static int dn_fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
+			u32 tb_id, u8 type, u8 scope, void *dst, int dst_len,
+			struct dn_fib_info *fi, unsigned int flags)
+{
+	struct rtmsg *rtm;
+	struct nlmsghdr *nlh;
+
+	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
+	if (!nlh)
+		return -EMSGSIZE;
+
+	rtm = nlmsg_data(nlh);
+	rtm->rtm_family = AF_DECnet;
+	rtm->rtm_dst_len = dst_len;
+	rtm->rtm_src_len = 0;
+	rtm->rtm_tos = 0;
+	rtm->rtm_table = tb_id;
+	rtm->rtm_flags = fi->fib_flags;
+	rtm->rtm_scope = scope;
+	rtm->rtm_type  = type;
+	rtm->rtm_protocol = fi->fib_protocol;
+
+	if (nla_put_u32(skb, RTA_TABLE, tb_id) < 0)
+		goto errout;
+
+	if (rtm->rtm_dst_len &&
+	    nla_put(skb, RTA_DST, 2, dst) < 0)
+		goto errout;
+
+	if (fi->fib_priority &&
+	    nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority) < 0)
+		goto errout;
+
+	if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
+		goto errout;
+
+	if (fi->fib_nhs == 1) {
+		if (fi->fib_nh->nh_gw &&
+		    nla_put_le16(skb, RTA_GATEWAY, fi->fib_nh->nh_gw) < 0)
+			goto errout;
+
+		if (fi->fib_nh->nh_oif &&
+		    nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif) < 0)
+			goto errout;
+	}
+
+	if (fi->fib_nhs > 1) {
+		struct rtnexthop *nhp;
+		struct nlattr *mp_head;
+
+		if (!(mp_head = nla_nest_start(skb, RTA_MULTIPATH)))
+			goto errout;
+
+		for_nexthops(fi) {
+			if (!(nhp = nla_reserve_nohdr(skb, sizeof(*nhp))))
+				goto errout;
+
+			nhp->rtnh_flags = nh->nh_flags & 0xFF;
+			nhp->rtnh_hops = nh->nh_weight - 1;
+			nhp->rtnh_ifindex = nh->nh_oif;
+
+			if (nh->nh_gw &&
+			    nla_put_le16(skb, RTA_GATEWAY, nh->nh_gw) < 0)
+				goto errout;
+
+			nhp->rtnh_len = skb_tail_pointer(skb) - (unsigned char *)nhp;
+		} endfor_nexthops(fi);
+
+		nla_nest_end(skb, mp_head);
+	}
+
+	nlmsg_end(skb, nlh);
+	return 0;
+
+errout:
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
+}
+
+
+static void dn_rtmsg_fib(int event, struct dn_fib_node *f, int z, u32 tb_id,
+			struct nlmsghdr *nlh, struct netlink_skb_parms *req)
+{
+	struct sk_buff *skb;
+	u32 portid = req ? req->portid : 0;
+	int err = -ENOBUFS;
+
+	skb = nlmsg_new(dn_fib_nlmsg_size(DN_FIB_INFO(f)), GFP_KERNEL);
+	if (skb == NULL)
+		goto errout;
+
+	err = dn_fib_dump_info(skb, portid, nlh->nlmsg_seq, event, tb_id,
+			       f->fn_type, f->fn_scope, &f->fn_key, z,
+			       DN_FIB_INFO(f), 0);
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in dn_fib_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
+	rtnl_notify(skb, &init_net, portid, RTNLGRP_DECnet_ROUTE, nlh, GFP_KERNEL);
+	return;
+errout:
+	if (err < 0)
+		rtnl_set_sk_err(&init_net, RTNLGRP_DECnet_ROUTE, err);
+}
+
+static __inline__ int dn_hash_dump_bucket(struct sk_buff *skb,
+				struct netlink_callback *cb,
+				struct dn_fib_table *tb,
+				struct dn_zone *dz,
+				struct dn_fib_node *f)
+{
+	int i, s_i;
+
+	s_i = cb->args[4];
+	for(i = 0; f; i++, f = f->fn_next) {
+		if (i < s_i)
+			continue;
+		if (f->fn_state & DN_S_ZOMBIE)
+			continue;
+		if (dn_fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
+				cb->nlh->nlmsg_seq,
+				RTM_NEWROUTE,
+				tb->n,
+				(f->fn_state & DN_S_ZOMBIE) ? 0 : f->fn_type,
+				f->fn_scope, &f->fn_key, dz->dz_order,
+				f->fn_info, NLM_F_MULTI) < 0) {
+			cb->args[4] = i;
+			return -1;
+		}
+	}
+	cb->args[4] = i;
+	return skb->len;
+}
+
+static __inline__ int dn_hash_dump_zone(struct sk_buff *skb,
+				struct netlink_callback *cb,
+				struct dn_fib_table *tb,
+				struct dn_zone *dz)
+{
+	int h, s_h;
+
+	s_h = cb->args[3];
+	for(h = 0; h < dz->dz_divisor; h++) {
+		if (h < s_h)
+			continue;
+		if (h > s_h)
+			memset(&cb->args[4], 0, sizeof(cb->args) - 4*sizeof(cb->args[0]));
+		if (dz->dz_hash == NULL || dz->dz_hash[h] == NULL)
+			continue;
+		if (dn_hash_dump_bucket(skb, cb, tb, dz, dz->dz_hash[h]) < 0) {
+			cb->args[3] = h;
+			return -1;
+		}
+	}
+	cb->args[3] = h;
+	return skb->len;
+}
+
+static int dn_fib_table_dump(struct dn_fib_table *tb, struct sk_buff *skb,
+				struct netlink_callback *cb)
+{
+	int m, s_m;
+	struct dn_zone *dz;
+	struct dn_hash *table = (struct dn_hash *)tb->data;
+
+	s_m = cb->args[2];
+	read_lock(&dn_fib_tables_lock);
+	for(dz = table->dh_zone_list, m = 0; dz; dz = dz->dz_next, m++) {
+		if (m < s_m)
+			continue;
+		if (m > s_m)
+			memset(&cb->args[3], 0, sizeof(cb->args) - 3*sizeof(cb->args[0]));
+
+		if (dn_hash_dump_zone(skb, cb, tb, dz) < 0) {
+			cb->args[2] = m;
+			read_unlock(&dn_fib_tables_lock);
+			return -1;
+		}
+	}
+	read_unlock(&dn_fib_tables_lock);
+	cb->args[2] = m;
+
+	return skb->len;
+}
+
+int dn_fib_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	unsigned int h, s_h;
+	unsigned int e = 0, s_e;
+	struct dn_fib_table *tb;
+	int dumped = 0;
+
+	if (!net_eq(net, &init_net))
+		return 0;
+
+	if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
+		((struct rtmsg *)nlmsg_data(cb->nlh))->rtm_flags&RTM_F_CLONED)
+			return dn_cache_dump(skb, cb);
+
+	s_h = cb->args[0];
+	s_e = cb->args[1];
+
+	for (h = s_h; h < DN_FIB_TABLE_HASHSZ; h++, s_h = 0) {
+		e = 0;
+		hlist_for_each_entry(tb, &dn_fib_table_hash[h], hlist) {
+			if (e < s_e)
+				goto next;
+			if (dumped)
+				memset(&cb->args[2], 0, sizeof(cb->args) -
+						 2 * sizeof(cb->args[0]));
+			if (tb->dump(tb, skb, cb) < 0)
+				goto out;
+			dumped = 1;
+next:
+			e++;
+		}
+	}
+out:
+	cb->args[1] = e;
+	cb->args[0] = h;
+
+	return skb->len;
+}
+
+static int dn_fib_table_insert(struct dn_fib_table *tb, struct rtmsg *r, struct nlattr *attrs[],
+			       struct nlmsghdr *n, struct netlink_skb_parms *req)
+{
+	struct dn_hash *table = (struct dn_hash *)tb->data;
+	struct dn_fib_node *new_f, *f, **fp, **del_fp;
+	struct dn_zone *dz;
+	struct dn_fib_info *fi;
+	int z = r->rtm_dst_len;
+	int type = r->rtm_type;
+	dn_fib_key_t key;
+	int err;
+
+	if (z > 16)
+		return -EINVAL;
+
+	dz = table->dh_zones[z];
+	if (!dz && !(dz = dn_new_zone(table, z)))
+		return -ENOBUFS;
+
+	dz_key_0(key);
+	if (attrs[RTA_DST]) {
+		__le16 dst = nla_get_le16(attrs[RTA_DST]);
+		if (dst & ~DZ_MASK(dz))
+			return -EINVAL;
+		key = dz_key(dst, dz);
+	}
+
+	if ((fi = dn_fib_create_info(r, attrs, n, &err)) == NULL)
+		return err;
+
+	if (dz->dz_nent > (dz->dz_divisor << 2) &&
+			dz->dz_divisor > DN_MAX_DIVISOR &&
+			(z==16 || (1<<z) > dz->dz_divisor))
+		dn_rehash_zone(dz);
+
+	fp = dn_chain_p(key, dz);
+
+	DN_FIB_SCAN(f, fp) {
+		if (dn_key_leq(key, f->fn_key))
+			break;
+	}
+
+	del_fp = NULL;
+
+	if (f && (f->fn_state & DN_S_ZOMBIE) &&
+			dn_key_eq(f->fn_key, key)) {
+		del_fp = fp;
+		fp = &f->fn_next;
+		f = *fp;
+		goto create;
+	}
+
+	DN_FIB_SCAN_KEY(f, fp, key) {
+		if (fi->fib_priority <= DN_FIB_INFO(f)->fib_priority)
+			break;
+	}
+
+	if (f && dn_key_eq(f->fn_key, key) &&
+			fi->fib_priority == DN_FIB_INFO(f)->fib_priority) {
+		struct dn_fib_node **ins_fp;
+
+		err = -EEXIST;
+		if (n->nlmsg_flags & NLM_F_EXCL)
+			goto out;
+
+		if (n->nlmsg_flags & NLM_F_REPLACE) {
+			del_fp = fp;
+			fp = &f->fn_next;
+			f = *fp;
+			goto replace;
+		}
+
+		ins_fp = fp;
+		err = -EEXIST;
+
+		DN_FIB_SCAN_KEY(f, fp, key) {
+			if (fi->fib_priority != DN_FIB_INFO(f)->fib_priority)
+				break;
+			if (f->fn_type == type &&
+			    f->fn_scope == r->rtm_scope &&
+			    DN_FIB_INFO(f) == fi)
+				goto out;
+		}
+
+		if (!(n->nlmsg_flags & NLM_F_APPEND)) {
+			fp = ins_fp;
+			f = *fp;
+		}
+	}
+
+create:
+	err = -ENOENT;
+	if (!(n->nlmsg_flags & NLM_F_CREATE))
+		goto out;
+
+replace:
+	err = -ENOBUFS;
+	new_f = kmem_cache_zalloc(dn_hash_kmem, GFP_KERNEL);
+	if (new_f == NULL)
+		goto out;
+
+	new_f->fn_key = key;
+	new_f->fn_type = type;
+	new_f->fn_scope = r->rtm_scope;
+	DN_FIB_INFO(new_f) = fi;
+
+	new_f->fn_next = f;
+	write_lock_bh(&dn_fib_tables_lock);
+	*fp = new_f;
+	write_unlock_bh(&dn_fib_tables_lock);
+	dz->dz_nent++;
+
+	if (del_fp) {
+		f = *del_fp;
+		write_lock_bh(&dn_fib_tables_lock);
+		*del_fp = f->fn_next;
+		write_unlock_bh(&dn_fib_tables_lock);
+
+		if (!(f->fn_state & DN_S_ZOMBIE))
+			dn_rtmsg_fib(RTM_DELROUTE, f, z, tb->n, n, req);
+		if (f->fn_state & DN_S_ACCESSED)
+			dn_rt_cache_flush(-1);
+		dn_free_node(f);
+		dz->dz_nent--;
+	} else {
+		dn_rt_cache_flush(-1);
+	}
+
+	dn_rtmsg_fib(RTM_NEWROUTE, new_f, z, tb->n, n, req);
+
+	return 0;
+out:
+	dn_fib_release_info(fi);
+	return err;
+}
+
+
+static int dn_fib_table_delete(struct dn_fib_table *tb, struct rtmsg *r, struct nlattr *attrs[],
+			       struct nlmsghdr *n, struct netlink_skb_parms *req)
+{
+	struct dn_hash *table = (struct dn_hash*)tb->data;
+	struct dn_fib_node **fp, **del_fp, *f;
+	int z = r->rtm_dst_len;
+	struct dn_zone *dz;
+	dn_fib_key_t key;
+	int matched;
+
+
+	if (z > 16)
+		return -EINVAL;
+
+	if ((dz = table->dh_zones[z]) == NULL)
+		return -ESRCH;
+
+	dz_key_0(key);
+	if (attrs[RTA_DST]) {
+		__le16 dst = nla_get_le16(attrs[RTA_DST]);
+		if (dst & ~DZ_MASK(dz))
+			return -EINVAL;
+		key = dz_key(dst, dz);
+	}
+
+	fp = dn_chain_p(key, dz);
+
+	DN_FIB_SCAN(f, fp) {
+		if (dn_key_eq(f->fn_key, key))
+			break;
+		if (dn_key_leq(key, f->fn_key))
+			return -ESRCH;
+	}
+
+	matched = 0;
+	del_fp = NULL;
+	DN_FIB_SCAN_KEY(f, fp, key) {
+		struct dn_fib_info *fi = DN_FIB_INFO(f);
+
+		if (f->fn_state & DN_S_ZOMBIE)
+			return -ESRCH;
+
+		matched++;
+
+		if (del_fp == NULL &&
+				(!r->rtm_type || f->fn_type == r->rtm_type) &&
+				(r->rtm_scope == RT_SCOPE_NOWHERE || f->fn_scope == r->rtm_scope) &&
+				(!r->rtm_protocol ||
+					fi->fib_protocol == r->rtm_protocol) &&
+				dn_fib_nh_match(r, n, attrs, fi) == 0)
+			del_fp = fp;
+	}
+
+	if (del_fp) {
+		f = *del_fp;
+		dn_rtmsg_fib(RTM_DELROUTE, f, z, tb->n, n, req);
+
+		if (matched != 1) {
+			write_lock_bh(&dn_fib_tables_lock);
+			*del_fp = f->fn_next;
+			write_unlock_bh(&dn_fib_tables_lock);
+
+			if (f->fn_state & DN_S_ACCESSED)
+				dn_rt_cache_flush(-1);
+			dn_free_node(f);
+			dz->dz_nent--;
+		} else {
+			f->fn_state |= DN_S_ZOMBIE;
+			if (f->fn_state & DN_S_ACCESSED) {
+				f->fn_state &= ~DN_S_ACCESSED;
+				dn_rt_cache_flush(-1);
+			}
+			if (++dn_fib_hash_zombies > 128)
+				dn_fib_flush();
+		}
+
+		return 0;
+	}
+
+	return -ESRCH;
+}
+
+static inline int dn_flush_list(struct dn_fib_node **fp, int z, struct dn_hash *table)
+{
+	int found = 0;
+	struct dn_fib_node *f;
+
+	while((f = *fp) != NULL) {
+		struct dn_fib_info *fi = DN_FIB_INFO(f);
+
+		if (fi && ((f->fn_state & DN_S_ZOMBIE) || (fi->fib_flags & RTNH_F_DEAD))) {
+			write_lock_bh(&dn_fib_tables_lock);
+			*fp = f->fn_next;
+			write_unlock_bh(&dn_fib_tables_lock);
+
+			dn_free_node(f);
+			found++;
+			continue;
+		}
+		fp = &f->fn_next;
+	}
+
+	return found;
+}
+
+static int dn_fib_table_flush(struct dn_fib_table *tb)
+{
+	struct dn_hash *table = (struct dn_hash *)tb->data;
+	struct dn_zone *dz;
+	int found = 0;
+
+	dn_fib_hash_zombies = 0;
+	for(dz = table->dh_zone_list; dz; dz = dz->dz_next) {
+		int i;
+		int tmp = 0;
+		for(i = dz->dz_divisor-1; i >= 0; i--)
+			tmp += dn_flush_list(&dz->dz_hash[i], dz->dz_order, table);
+		dz->dz_nent -= tmp;
+		found += tmp;
+	}
+
+	return found;
+}
+
+static int dn_fib_table_lookup(struct dn_fib_table *tb, const struct flowidn *flp, struct dn_fib_res *res)
+{
+	int err;
+	struct dn_zone *dz;
+	struct dn_hash *t = (struct dn_hash *)tb->data;
+
+	read_lock(&dn_fib_tables_lock);
+	for(dz = t->dh_zone_list; dz; dz = dz->dz_next) {
+		struct dn_fib_node *f;
+		dn_fib_key_t k = dz_key(flp->daddr, dz);
+
+		for(f = dz_chain(k, dz); f; f = f->fn_next) {
+			if (!dn_key_eq(k, f->fn_key)) {
+				if (dn_key_leq(k, f->fn_key))
+					break;
+				else
+					continue;
+			}
+
+			f->fn_state |= DN_S_ACCESSED;
+
+			if (f->fn_state&DN_S_ZOMBIE)
+				continue;
+
+			if (f->fn_scope < flp->flowidn_scope)
+				continue;
+
+			err = dn_fib_semantic_match(f->fn_type, DN_FIB_INFO(f), flp, res);
+
+			if (err == 0) {
+				res->type = f->fn_type;
+				res->scope = f->fn_scope;
+				res->prefixlen = dz->dz_order;
+				goto out;
+			}
+			if (err < 0)
+				goto out;
+		}
+	}
+	err = 1;
+out:
+	read_unlock(&dn_fib_tables_lock);
+	return err;
+}
+
+
+struct dn_fib_table *dn_fib_get_table(u32 n, int create)
+{
+	struct dn_fib_table *t;
+	unsigned int h;
+
+	if (n < RT_TABLE_MIN)
+		return NULL;
+
+	if (n > RT_TABLE_MAX)
+		return NULL;
+
+	h = n & (DN_FIB_TABLE_HASHSZ - 1);
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(t, &dn_fib_table_hash[h], hlist) {
+		if (t->n == n) {
+			rcu_read_unlock();
+			return t;
+		}
+	}
+	rcu_read_unlock();
+
+	if (!create)
+		return NULL;
+
+	if (in_interrupt()) {
+		net_dbg_ratelimited("DECnet: BUG! Attempt to create routing table from interrupt\n");
+		return NULL;
+	}
+
+	t = kzalloc(sizeof(struct dn_fib_table) + sizeof(struct dn_hash),
+		    GFP_KERNEL);
+	if (t == NULL)
+		return NULL;
+
+	t->n = n;
+	t->insert = dn_fib_table_insert;
+	t->delete = dn_fib_table_delete;
+	t->lookup = dn_fib_table_lookup;
+	t->flush  = dn_fib_table_flush;
+	t->dump = dn_fib_table_dump;
+	hlist_add_head_rcu(&t->hlist, &dn_fib_table_hash[h]);
+
+	return t;
+}
+
+struct dn_fib_table *dn_fib_empty_table(void)
+{
+	u32 id;
+
+	for(id = RT_TABLE_MIN; id <= RT_TABLE_MAX; id++)
+		if (dn_fib_get_table(id, 0) == NULL)
+			return dn_fib_get_table(id, 1);
+	return NULL;
+}
+
+void dn_fib_flush(void)
+{
+	int flushed = 0;
+	struct dn_fib_table *tb;
+	unsigned int h;
+
+	for (h = 0; h < DN_FIB_TABLE_HASHSZ; h++) {
+		hlist_for_each_entry(tb, &dn_fib_table_hash[h], hlist)
+			flushed += tb->flush(tb);
+	}
+
+	if (flushed)
+		dn_rt_cache_flush(-1);
+}
+
+void __init dn_fib_table_init(void)
+{
+	dn_hash_kmem = kmem_cache_create("dn_fib_info_cache",
+					sizeof(struct dn_fib_info),
+					0, SLAB_HWCACHE_ALIGN,
+					NULL);
+}
+
+void __exit dn_fib_table_cleanup(void)
+{
+	struct dn_fib_table *t;
+	struct hlist_node *next;
+	unsigned int h;
+
+	write_lock(&dn_fib_tables_lock);
+	for (h = 0; h < DN_FIB_TABLE_HASHSZ; h++) {
+		hlist_for_each_entry_safe(t, next, &dn_fib_table_hash[h],
+					  hlist) {
+			hlist_del(&t->hlist);
+			kfree(t);
+		}
+	}
+	write_unlock(&dn_fib_tables_lock);
+}
diff --git a/net/decnet/dn_timer.c b/net/decnet/dn_timer.c
new file mode 100644
index 000000000..aa4155875
--- /dev/null
+++ b/net/decnet/dn_timer.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Socket Timer Functions
+ *
+ * Author:      Steve Whitehouse <SteveW@ACM.org>
+ *
+ *
+ * Changes:
+ *       Steve Whitehouse      : Made keepalive timer part of the same
+ *                               timer idea.
+ *       Steve Whitehouse      : Added checks for sk->sock_readers
+ *       David S. Miller       : New socket locking
+ *       Steve Whitehouse      : Timer grabs socket ref.
+ */
+#include <linux/net.h>
+#include <linux/socket.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <net/sock.h>
+#include <linux/atomic.h>
+#include <linux/jiffies.h>
+#include <net/flow.h>
+#include <net/dn.h>
+
+/*
+ * Slow timer is for everything else (n * 500mS)
+ */
+
+#define SLOW_INTERVAL (HZ/2)
+
+static void dn_slow_timer(struct timer_list *t);
+
+void dn_start_slow_timer(struct sock *sk)
+{
+	timer_setup(&sk->sk_timer, dn_slow_timer, 0);
+	sk_reset_timer(sk, &sk->sk_timer, jiffies + SLOW_INTERVAL);
+}
+
+void dn_stop_slow_timer(struct sock *sk)
+{
+	sk_stop_timer(sk, &sk->sk_timer);
+}
+
+static void dn_slow_timer(struct timer_list *t)
+{
+	struct sock *sk = from_timer(sk, t, sk_timer);
+	struct dn_scp *scp = DN_SK(sk);
+
+	bh_lock_sock(sk);
+
+	if (sock_owned_by_user(sk)) {
+		sk_reset_timer(sk, &sk->sk_timer, jiffies + HZ / 10);
+		goto out;
+	}
+
+	/*
+	 * The persist timer is the standard slow timer used for retransmits
+	 * in both connection establishment and disconnection as well as
+	 * in the RUN state. The different states are catered for by changing
+	 * the function pointer in the socket. Setting the timer to a value
+	 * of zero turns it off. We allow the persist_fxn to turn the
+	 * timer off in a permant way by returning non-zero, so that
+	 * timer based routines may remove sockets. This is why we have a
+	 * sock_hold()/sock_put() around the timer to prevent the socket
+	 * going away in the middle.
+	 */
+	if (scp->persist && scp->persist_fxn) {
+		if (scp->persist <= SLOW_INTERVAL) {
+			scp->persist = 0;
+
+			if (scp->persist_fxn(sk))
+				goto out;
+		} else {
+			scp->persist -= SLOW_INTERVAL;
+		}
+	}
+
+	/*
+	 * Check for keepalive timeout. After the other timer 'cos if
+	 * the previous timer caused a retransmit, we don't need to
+	 * do this. scp->stamp is the last time that we sent a packet.
+	 * The keepalive function sends a link service packet to the
+	 * other end. If it remains unacknowledged, the standard
+	 * socket timers will eventually shut the socket down. Each
+	 * time we do this, scp->stamp will be updated, thus
+	 * we won't try and send another until scp->keepalive has passed
+	 * since the last successful transmission.
+	 */
+	if (scp->keepalive && scp->keepalive_fxn && (scp->state == DN_RUN)) {
+		if (time_after_eq(jiffies, scp->stamp + scp->keepalive))
+			scp->keepalive_fxn(sk);
+	}
+
+	sk_reset_timer(sk, &sk->sk_timer, jiffies + SLOW_INTERVAL);
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
diff --git a/net/decnet/netfilter/Kconfig b/net/decnet/netfilter/Kconfig
new file mode 100644
index 000000000..8d7c109d5
--- /dev/null
+++ b/net/decnet/netfilter/Kconfig
@@ -0,0 +1,16 @@
+#
+# DECnet netfilter configuration
+#
+
+menu "DECnet: Netfilter Configuration"
+	depends on DECNET && NETFILTER
+	depends on NETFILTER_ADVANCED
+
+config DECNET_NF_GRABULATOR
+	tristate "Routing message grabulator (for userland routing daemon)"
+	help
+	  Enable this module if you want to use the userland DECnet routing
+	  daemon. You will also need to enable routing support for DECnet
+	  unless you just want to monitor routing messages from other nodes.
+
+endmenu
diff --git a/net/decnet/netfilter/Makefile b/net/decnet/netfilter/Makefile
new file mode 100644
index 000000000..b579e5213
--- /dev/null
+++ b/net/decnet/netfilter/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for DECnet netfilter modules
+#
+
+obj-$(CONFIG_DECNET_NF_GRABULATOR) += dn_rtmsg.o
diff --git a/net/decnet/netfilter/dn_rtmsg.c b/net/decnet/netfilter/dn_rtmsg.c
new file mode 100644
index 000000000..a4faacadd
--- /dev/null
+++ b/net/decnet/netfilter/dn_rtmsg.c
@@ -0,0 +1,160 @@
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet Routing Message Grabulator
+ *
+ *              (C) 2000 ChyGwyn Limited  -  http://www.chygwyn.com/
+ *              This code may be copied under the GPL v.2 or at your option
+ *              any later version.
+ *
+ * Author:      Steven Whitehouse <steve@chygwyn.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/netfilter.h>
+#include <linux/spinlock.h>
+#include <net/netlink.h>
+#include <linux/netfilter_decnet.h>
+
+#include <net/sock.h>
+#include <net/flow.h>
+#include <net/dn.h>
+#include <net/dn_route.h>
+
+static struct sock *dnrmg = NULL;
+
+
+static struct sk_buff *dnrmg_build_message(struct sk_buff *rt_skb, int *errp)
+{
+	struct sk_buff *skb = NULL;
+	size_t size;
+	sk_buff_data_t old_tail;
+	struct nlmsghdr *nlh;
+	unsigned char *ptr;
+	struct nf_dn_rtmsg *rtm;
+
+	size = NLMSG_ALIGN(rt_skb->len) +
+	       NLMSG_ALIGN(sizeof(struct nf_dn_rtmsg));
+	skb = nlmsg_new(size, GFP_ATOMIC);
+	if (!skb) {
+		*errp = -ENOMEM;
+		return NULL;
+	}
+	old_tail = skb->tail;
+	nlh = nlmsg_put(skb, 0, 0, 0, size, 0);
+	if (!nlh) {
+		kfree_skb(skb);
+		*errp = -ENOMEM;
+		return NULL;
+	}
+	rtm = (struct nf_dn_rtmsg *)nlmsg_data(nlh);
+	rtm->nfdn_ifindex = rt_skb->dev->ifindex;
+	ptr = NFDN_RTMSG(rtm);
+	skb_copy_from_linear_data(rt_skb, ptr, rt_skb->len);
+	nlh->nlmsg_len = skb->tail - old_tail;
+	return skb;
+}
+
+static void dnrmg_send_peer(struct sk_buff *skb)
+{
+	struct sk_buff *skb2;
+	int status = 0;
+	int group = 0;
+	unsigned char flags = *skb->data;
+
+	switch (flags & DN_RT_CNTL_MSK) {
+	case DN_RT_PKT_L1RT:
+		group = DNRNG_NLGRP_L1;
+		break;
+	case DN_RT_PKT_L2RT:
+		group = DNRNG_NLGRP_L2;
+		break;
+	default:
+		return;
+	}
+
+	skb2 = dnrmg_build_message(skb, &status);
+	if (skb2 == NULL)
+		return;
+	NETLINK_CB(skb2).dst_group = group;
+	netlink_broadcast(dnrmg, skb2, 0, group, GFP_ATOMIC);
+}
+
+
+static unsigned int dnrmg_hook(void *priv,
+			struct sk_buff *skb,
+			const struct nf_hook_state *state)
+{
+	dnrmg_send_peer(skb);
+	return NF_ACCEPT;
+}
+
+
+#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err), NULL); return; } while (0)
+
+static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(skb);
+
+	if (skb->len < sizeof(*nlh) ||
+	    nlh->nlmsg_len < sizeof(*nlh) ||
+	    skb->len < nlh->nlmsg_len)
+		return;
+
+	if (!netlink_capable(skb, CAP_NET_ADMIN))
+		RCV_SKB_FAIL(-EPERM);
+
+	/* Eventually we might send routing messages too */
+
+	RCV_SKB_FAIL(-EINVAL);
+}
+
+static const struct nf_hook_ops dnrmg_ops = {
+	.hook		= dnrmg_hook,
+	.pf		= NFPROTO_DECNET,
+	.hooknum	= NF_DN_ROUTE,
+	.priority	= NF_DN_PRI_DNRTMSG,
+};
+
+static int __init dn_rtmsg_init(void)
+{
+	int rv = 0;
+	struct netlink_kernel_cfg cfg = {
+		.groups	= DNRNG_NLGRP_MAX,
+		.input	= dnrmg_receive_user_skb,
+	};
+
+	dnrmg = netlink_kernel_create(&init_net, NETLINK_DNRTMSG, &cfg);
+	if (dnrmg == NULL) {
+		printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket");
+		return -ENOMEM;
+	}
+
+	rv = nf_register_net_hook(&init_net, &dnrmg_ops);
+	if (rv) {
+		netlink_kernel_release(dnrmg);
+	}
+
+	return rv;
+}
+
+static void __exit dn_rtmsg_fini(void)
+{
+	nf_unregister_net_hook(&init_net, &dnrmg_ops);
+	netlink_kernel_release(dnrmg);
+}
+
+
+MODULE_DESCRIPTION("DECnet Routing Message Grabulator");
+MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG);
+
+module_init(dn_rtmsg_init);
+module_exit(dn_rtmsg_fini);
diff --git a/net/decnet/sysctl_net_decnet.c b/net/decnet/sysctl_net_decnet.c
new file mode 100644
index 000000000..55bf64a22
--- /dev/null
+++ b/net/decnet/sysctl_net_decnet.c
@@ -0,0 +1,373 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DECnet       An implementation of the DECnet protocol suite for the LINUX
+ *              operating system.  DECnet is implemented using the  BSD Socket
+ *              interface as the means of communication with the user level.
+ *
+ *              DECnet sysctl support functions
+ *
+ * Author:      Steve Whitehouse <SteveW@ACM.org>
+ *
+ *
+ * Changes:
+ * Steve Whitehouse - C99 changes and default device handling
+ * Steve Whitehouse - Memory buffer settings, like the tcp ones
+ *
+ */
+#include <linux/mm.h>
+#include <linux/sysctl.h>
+#include <linux/fs.h>
+#include <linux/netdevice.h>
+#include <linux/string.h>
+#include <net/neighbour.h>
+#include <net/dst.h>
+#include <net/flow.h>
+
+#include <linux/uaccess.h>
+
+#include <net/dn.h>
+#include <net/dn_dev.h>
+#include <net/dn_route.h>
+
+
+int decnet_debug_level;
+int decnet_time_wait = 30;
+int decnet_dn_count = 1;
+int decnet_di_count = 3;
+int decnet_dr_count = 3;
+int decnet_log_martians = 1;
+int decnet_no_fc_max_cwnd = NSP_MIN_WINDOW;
+
+/* Reasonable defaults, I hope, based on tcp's defaults */
+long sysctl_decnet_mem[3] = { 768 << 3, 1024 << 3, 1536 << 3 };
+int sysctl_decnet_wmem[3] = { 4 * 1024, 16 * 1024, 128 * 1024 };
+int sysctl_decnet_rmem[3] = { 4 * 1024, 87380, 87380 * 2 };
+
+#ifdef CONFIG_SYSCTL
+extern int decnet_dst_gc_interval;
+static int min_decnet_time_wait[] = { 5 };
+static int max_decnet_time_wait[] = { 600 };
+static int min_state_count[] = { 1 };
+static int max_state_count[] = { NSP_MAXRXTSHIFT };
+static int min_decnet_dst_gc_interval[] = { 1 };
+static int max_decnet_dst_gc_interval[] = { 60 };
+static int min_decnet_no_fc_max_cwnd[] = { NSP_MIN_WINDOW };
+static int max_decnet_no_fc_max_cwnd[] = { NSP_MAX_WINDOW };
+static char node_name[7] = "???";
+
+static struct ctl_table_header *dn_table_header = NULL;
+
+/*
+ * ctype.h :-)
+ */
+#define ISNUM(x) (((x) >= '0') && ((x) <= '9'))
+#define ISLOWER(x) (((x) >= 'a') && ((x) <= 'z'))
+#define ISUPPER(x) (((x) >= 'A') && ((x) <= 'Z'))
+#define ISALPHA(x) (ISLOWER(x) || ISUPPER(x))
+#define INVALID_END_CHAR(x) (ISNUM(x) || ISALPHA(x))
+
+static void strip_it(char *str)
+{
+	for(;;) {
+		switch (*str) {
+		case ' ':
+		case '\n':
+		case '\r':
+		case ':':
+			*str = 0;
+			/* Fallthrough */
+		case 0:
+			return;
+		}
+		str++;
+	}
+}
+
+/*
+ * Simple routine to parse an ascii DECnet address
+ * into a network order address.
+ */
+static int parse_addr(__le16 *addr, char *str)
+{
+	__u16 area, node;
+
+	while(*str && !ISNUM(*str)) str++;
+
+	if (*str == 0)
+		return -1;
+
+	area = (*str++ - '0');
+	if (ISNUM(*str)) {
+		area *= 10;
+		area += (*str++ - '0');
+	}
+
+	if (*str++ != '.')
+		return -1;
+
+	if (!ISNUM(*str))
+		return -1;
+
+	node = *str++ - '0';
+	if (ISNUM(*str)) {
+		node *= 10;
+		node += (*str++ - '0');
+	}
+	if (ISNUM(*str)) {
+		node *= 10;
+		node += (*str++ - '0');
+	}
+	if (ISNUM(*str)) {
+		node *= 10;
+		node += (*str++ - '0');
+	}
+
+	if ((node > 1023) || (area > 63))
+		return -1;
+
+	if (INVALID_END_CHAR(*str))
+		return -1;
+
+	*addr = cpu_to_le16((area << 10) | node);
+
+	return 0;
+}
+
+static int dn_node_address_handler(struct ctl_table *table, int write,
+				void __user *buffer,
+				size_t *lenp, loff_t *ppos)
+{
+	char addr[DN_ASCBUF_LEN];
+	size_t len;
+	__le16 dnaddr;
+
+	if (!*lenp || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	if (write) {
+		len = (*lenp < DN_ASCBUF_LEN) ? *lenp : (DN_ASCBUF_LEN-1);
+
+		if (copy_from_user(addr, buffer, len))
+			return -EFAULT;
+
+		addr[len] = 0;
+		strip_it(addr);
+
+		if (parse_addr(&dnaddr, addr))
+			return -EINVAL;
+
+		dn_dev_devices_off();
+
+		decnet_address = dnaddr;
+
+		dn_dev_devices_on();
+
+		*ppos += len;
+
+		return 0;
+	}
+
+	dn_addr2asc(le16_to_cpu(decnet_address), addr);
+	len = strlen(addr);
+	addr[len++] = '\n';
+
+	if (len > *lenp) len = *lenp;
+
+	if (copy_to_user(buffer, addr, len))
+		return -EFAULT;
+
+	*lenp = len;
+	*ppos += len;
+
+	return 0;
+}
+
+static int dn_def_dev_handler(struct ctl_table *table, int write,
+				void __user *buffer,
+				size_t *lenp, loff_t *ppos)
+{
+	size_t len;
+	struct net_device *dev;
+	char devname[17];
+
+	if (!*lenp || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	if (write) {
+		if (*lenp > 16)
+			return -E2BIG;
+
+		if (copy_from_user(devname, buffer, *lenp))
+			return -EFAULT;
+
+		devname[*lenp] = 0;
+		strip_it(devname);
+
+		dev = dev_get_by_name(&init_net, devname);
+		if (dev == NULL)
+			return -ENODEV;
+
+		if (dev->dn_ptr == NULL) {
+			dev_put(dev);
+			return -ENODEV;
+		}
+
+		if (dn_dev_set_default(dev, 1)) {
+			dev_put(dev);
+			return -ENODEV;
+		}
+		*ppos += *lenp;
+
+		return 0;
+	}
+
+	dev = dn_dev_get_default();
+	if (dev == NULL) {
+		*lenp = 0;
+		return 0;
+	}
+
+	strcpy(devname, dev->name);
+	dev_put(dev);
+	len = strlen(devname);
+	devname[len++] = '\n';
+
+	if (len > *lenp) len = *lenp;
+
+	if (copy_to_user(buffer, devname, len))
+		return -EFAULT;
+
+	*lenp = len;
+	*ppos += len;
+
+	return 0;
+}
+
+static struct ctl_table dn_table[] = {
+	{
+		.procname = "node_address",
+		.maxlen = 7,
+		.mode = 0644,
+		.proc_handler = dn_node_address_handler,
+	},
+	{
+		.procname = "node_name",
+		.data = node_name,
+		.maxlen = 7,
+		.mode = 0644,
+		.proc_handler = proc_dostring,
+	},
+	{
+		.procname = "default_device",
+		.maxlen = 16,
+		.mode = 0644,
+		.proc_handler = dn_def_dev_handler,
+	},
+	{
+		.procname = "time_wait",
+		.data = &decnet_time_wait,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_decnet_time_wait,
+		.extra2 = &max_decnet_time_wait
+	},
+	{
+		.procname = "dn_count",
+		.data = &decnet_dn_count,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_state_count,
+		.extra2 = &max_state_count
+	},
+	{
+		.procname = "di_count",
+		.data = &decnet_di_count,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_state_count,
+		.extra2 = &max_state_count
+	},
+	{
+		.procname = "dr_count",
+		.data = &decnet_dr_count,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_state_count,
+		.extra2 = &max_state_count
+	},
+	{
+		.procname = "dst_gc_interval",
+		.data = &decnet_dst_gc_interval,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_decnet_dst_gc_interval,
+		.extra2 = &max_decnet_dst_gc_interval
+	},
+	{
+		.procname = "no_fc_max_cwnd",
+		.data = &decnet_no_fc_max_cwnd,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = &min_decnet_no_fc_max_cwnd,
+		.extra2 = &max_decnet_no_fc_max_cwnd
+	},
+       {
+		.procname = "decnet_mem",
+		.data = &sysctl_decnet_mem,
+		.maxlen = sizeof(sysctl_decnet_mem),
+		.mode = 0644,
+		.proc_handler = proc_doulongvec_minmax
+	},
+	{
+		.procname = "decnet_rmem",
+		.data = &sysctl_decnet_rmem,
+		.maxlen = sizeof(sysctl_decnet_rmem),
+		.mode = 0644,
+		.proc_handler = proc_dointvec,
+	},
+	{
+		.procname = "decnet_wmem",
+		.data = &sysctl_decnet_wmem,
+		.maxlen = sizeof(sysctl_decnet_wmem),
+		.mode = 0644,
+		.proc_handler = proc_dointvec,
+	},
+	{
+		.procname = "debug",
+		.data = &decnet_debug_level,
+		.maxlen = sizeof(int),
+		.mode = 0644,
+		.proc_handler = proc_dointvec,
+	},
+	{ }
+};
+
+void dn_register_sysctl(void)
+{
+	dn_table_header = register_net_sysctl(&init_net, "net/decnet", dn_table);
+}
+
+void dn_unregister_sysctl(void)
+{
+	unregister_net_sysctl_table(dn_table_header);
+}
+
+#else  /* CONFIG_SYSCTL */
+void dn_unregister_sysctl(void)
+{
+}
+void dn_register_sysctl(void)
+{
+}
+
+#endif