Adding upstream version 6.1.76.upstream/6.1.76

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

20 files changed, 6863 insertions, 0 deletions

diff --git a/net/ax25/Kconfig b/net/ax25/Kconfig
new file mode 100644
index 000000000..d3a9843a0
--- /dev/null
+++ b/net/ax25/Kconfig
@@ -0,0 +1,122 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Amateur Radio protocols and AX.25 device configuration
+#
+
+menuconfig HAMRADIO
+	depends on NET && !S390
+	bool "Amateur Radio support"
+	help
+	  If you want to connect your Linux box to an amateur radio, answer Y
+	  here. You want to read <https://www.tapr.org/>
+	  and more specifically about AX.25 on Linux
+	  <http://www.linux-ax25.org/>.
+
+	  Note that the answer to this question won't directly affect the
+	  kernel: saying N will just cause the configurator to skip all
+	  the questions about amateur radio.
+
+comment "Packet Radio protocols"
+	depends on HAMRADIO
+
+config AX25
+	tristate "Amateur Radio AX.25 Level 2 protocol"
+	depends on HAMRADIO
+	help
+	  This is the protocol used for computer communication over amateur
+	  radio. It is either used by itself for point-to-point links, or to
+	  carry other protocols such as tcp/ip. To use it, you need a device
+	  that connects your Linux box to your amateur radio. You can either
+	  use a low speed TNC (a Terminal Node Controller acts as a kind of
+	  modem connecting your computer's serial port to your radio's
+	  microphone input and speaker output) supporting the KISS protocol or
+	  one of the various SCC cards that are supported by the generic Z8530
+	  or the DMA SCC driver. Another option are the Baycom modem serial
+	  and parallel port hacks or the sound card modem (supported by their
+	  own drivers). If you say Y here, you also have to say Y to one of
+	  those drivers.
+
+	  Information about where to get supporting software for Linux amateur
+	  radio as well as information about how to configure an AX.25 port is
+	  contained in the AX25-HOWTO, available from
+	  <https://www.tldp.org/docs.html#howto>. You might also want to
+	  check out the file <file:Documentation/networking/ax25.rst> in the
+	  kernel source. More information about digital amateur radio in
+	  general is on the WWW at
+	  <https://www.tapr.org/>.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ax25.
+
+config AX25_DAMA_SLAVE
+	bool "AX.25 DAMA Slave support"
+	default y
+	depends on AX25
+	help
+	  DAMA is a mechanism to prevent collisions when doing AX.25
+	  networking. A DAMA server (called "master") accepts incoming traffic
+	  from clients (called "slaves") and redistributes it to other slaves.
+	  If you say Y here, your Linux box will act as a DAMA slave; this is
+	  transparent in that you don't have to do any special DAMA
+	  configuration. Linux cannot yet act as a DAMA server.  This option
+	  only compiles DAMA slave support into the kernel.  It still needs to
+	  be enabled at runtime.  For more about DAMA see
+	  <http://www.linux-ax25.org>.  If unsure, say Y.
+
+# placeholder until implemented
+config AX25_DAMA_MASTER
+	bool 'AX.25 DAMA Master support'
+	depends on AX25_DAMA_SLAVE && BROKEN
+	help
+	  DAMA is a mechanism to prevent collisions when doing AX.25
+	  networking. A DAMA server (called "master") accepts incoming traffic
+	  from clients (called "slaves") and redistributes it to other slaves.
+	  If you say Y here, your Linux box will act as a DAMA master; this is
+	  transparent in that you don't have to do any special DAMA
+	  configuration. Linux cannot yet act as a DAMA server.  This option
+	  only compiles DAMA slave support into the kernel.  It still needs to
+	  be explicitly enabled, so if unsure, say Y.
+
+config NETROM
+	tristate "Amateur Radio NET/ROM protocol"
+	depends on AX25
+	help
+	  NET/ROM is a network layer protocol on top of AX.25 useful for
+	  routing.
+
+	  A comprehensive listing of all the software for Linux amateur radio
+	  users as well as information about how to configure an AX.25 port is
+	  contained in the Linux Ham Wiki, available from
+	  <http://www.linux-ax25.org>. You also might want to check out the
+	  file <file:Documentation/networking/ax25.rst>. More information about
+	  digital amateur radio in general is on the WWW at
+	  <https://www.tapr.org/>.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called netrom.
+
+config ROSE
+	tristate "Amateur Radio X.25 PLP (Rose)"
+	depends on AX25
+	help
+	  The Packet Layer Protocol (PLP) is a way to route packets over X.25
+	  connections in general and amateur radio AX.25 connections in
+	  particular, essentially an alternative to NET/ROM.
+
+	  A comprehensive listing of all the software for Linux amateur radio
+	  users as well as information about how to configure an AX.25 port is
+	  contained in the Linux Ham Wiki, available from
+	  <http://www.linux-ax25.org>.  You also might want to check out the
+	  file <file:Documentation/networking/ax25.rst>. More information about
+	  digital amateur radio in general is on the WWW at
+	  <https://www.tapr.org/>.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rose.
+
+menu "AX.25 network device drivers"
+	depends on HAMRADIO && AX25
+
+source "drivers/net/hamradio/Kconfig"
+
+endmenu
diff --git a/net/ax25/Makefile b/net/ax25/Makefile
new file mode 100644
index 000000000..2e53affc8
--- /dev/null
+++ b/net/ax25/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux AX.25 layer.
+#
+
+obj-$(CONFIG_AX25) += ax25.o
+
+ax25-y	 := ax25_addr.o ax25_dev.o ax25_iface.o ax25_in.o ax25_ip.o ax25_out.o \
+	    ax25_route.o ax25_std_in.o ax25_std_subr.o ax25_std_timer.o \
+	    ax25_subr.o ax25_timer.o ax25_uid.o af_ax25.o
+ax25-$(CONFIG_AX25_DAMA_SLAVE) += ax25_ds_in.o ax25_ds_subr.o ax25_ds_timer.o
+ax25-$(CONFIG_SYSCTL) += sysctl_net_ax25.o
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
new file mode 100644
index 000000000..6b4c25a92
--- /dev/null
+++ b/net/ax25/af_ax25.c
@@ -0,0 +1,2083 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Darryl Miles G7LED (dlm@g7led.demon.co.uk)
+ * Copyright (C) Steven Whitehouse GW7RRM (stevew@acm.org)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
+ * Copyright (C) Hans Alblas PE1AYX (hans@esrac.ele.tue.nl)
+ * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
+ */
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/types.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/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/termios.h>	/* For TIOCINQ/OUTQ */
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/sysctl.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <net/net_namespace.h>
+#include <net/tcp_states.h>
+#include <net/ip.h>
+#include <net/arp.h>
+
+
+
+HLIST_HEAD(ax25_list);
+DEFINE_SPINLOCK(ax25_list_lock);
+
+static const struct proto_ops ax25_proto_ops;
+
+static void ax25_free_sock(struct sock *sk)
+{
+	ax25_cb_put(sk_to_ax25(sk));
+}
+
+/*
+ *	Socket removal during an interrupt is now safe.
+ */
+static void ax25_cb_del(ax25_cb *ax25)
+{
+	spin_lock_bh(&ax25_list_lock);
+	if (!hlist_unhashed(&ax25->ax25_node)) {
+		hlist_del_init(&ax25->ax25_node);
+		ax25_cb_put(ax25);
+	}
+	spin_unlock_bh(&ax25_list_lock);
+}
+
+/*
+ *	Kill all bound sockets on a dropped device.
+ */
+static void ax25_kill_by_device(struct net_device *dev)
+{
+	ax25_dev *ax25_dev;
+	ax25_cb *s;
+	struct sock *sk;
+
+	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
+		return;
+	ax25_dev->device_up = false;
+
+	spin_lock_bh(&ax25_list_lock);
+again:
+	ax25_for_each(s, &ax25_list) {
+		if (s->ax25_dev == ax25_dev) {
+			sk = s->sk;
+			if (!sk) {
+				spin_unlock_bh(&ax25_list_lock);
+				ax25_disconnect(s, ENETUNREACH);
+				s->ax25_dev = NULL;
+				ax25_cb_del(s);
+				spin_lock_bh(&ax25_list_lock);
+				goto again;
+			}
+			sock_hold(sk);
+			spin_unlock_bh(&ax25_list_lock);
+			lock_sock(sk);
+			ax25_disconnect(s, ENETUNREACH);
+			s->ax25_dev = NULL;
+			if (sk->sk_socket) {
+				netdev_put(ax25_dev->dev,
+					   &ax25_dev->dev_tracker);
+				ax25_dev_put(ax25_dev);
+			}
+			ax25_cb_del(s);
+			release_sock(sk);
+			spin_lock_bh(&ax25_list_lock);
+			sock_put(sk);
+			/* The entry could have been deleted from the
+			 * list meanwhile and thus the next pointer is
+			 * no longer valid.  Play it safe and restart
+			 * the scan.  Forward progress is ensured
+			 * because we set s->ax25_dev to NULL and we
+			 * are never passed a NULL 'dev' argument.
+			 */
+			goto again;
+		}
+	}
+	spin_unlock_bh(&ax25_list_lock);
+}
+
+/*
+ *	Handle device status changes.
+ */
+static int ax25_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;
+
+	/* Reject non AX.25 devices */
+	if (dev->type != ARPHRD_AX25)
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UP:
+		ax25_dev_device_up(dev);
+		break;
+	case NETDEV_DOWN:
+		ax25_kill_by_device(dev);
+		ax25_rt_device_down(dev);
+		ax25_dev_device_down(dev);
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+/*
+ *	Add a socket to the bound sockets list.
+ */
+void ax25_cb_add(ax25_cb *ax25)
+{
+	spin_lock_bh(&ax25_list_lock);
+	ax25_cb_hold(ax25);
+	hlist_add_head(&ax25->ax25_node, &ax25_list);
+	spin_unlock_bh(&ax25_list_lock);
+}
+
+/*
+ *	Find a socket that wants to accept the SABM we have just
+ *	received.
+ */
+struct sock *ax25_find_listener(ax25_address *addr, int digi,
+	struct net_device *dev, int type)
+{
+	ax25_cb *s;
+
+	spin_lock(&ax25_list_lock);
+	ax25_for_each(s, &ax25_list) {
+		if ((s->iamdigi && !digi) || (!s->iamdigi && digi))
+			continue;
+		if (s->sk && !ax25cmp(&s->source_addr, addr) &&
+		    s->sk->sk_type == type && s->sk->sk_state == TCP_LISTEN) {
+			/* If device is null we match any device */
+			if (s->ax25_dev == NULL || s->ax25_dev->dev == dev) {
+				sock_hold(s->sk);
+				spin_unlock(&ax25_list_lock);
+				return s->sk;
+			}
+		}
+	}
+	spin_unlock(&ax25_list_lock);
+
+	return NULL;
+}
+
+/*
+ *	Find an AX.25 socket given both ends.
+ */
+struct sock *ax25_get_socket(ax25_address *my_addr, ax25_address *dest_addr,
+	int type)
+{
+	struct sock *sk = NULL;
+	ax25_cb *s;
+
+	spin_lock(&ax25_list_lock);
+	ax25_for_each(s, &ax25_list) {
+		if (s->sk && !ax25cmp(&s->source_addr, my_addr) &&
+		    !ax25cmp(&s->dest_addr, dest_addr) &&
+		    s->sk->sk_type == type) {
+			sk = s->sk;
+			sock_hold(sk);
+			break;
+		}
+	}
+
+	spin_unlock(&ax25_list_lock);
+
+	return sk;
+}
+
+/*
+ *	Find an AX.25 control block given both ends. It will only pick up
+ *	floating AX.25 control blocks or non Raw socket bound control blocks.
+ */
+ax25_cb *ax25_find_cb(const ax25_address *src_addr, ax25_address *dest_addr,
+	ax25_digi *digi, struct net_device *dev)
+{
+	ax25_cb *s;
+
+	spin_lock_bh(&ax25_list_lock);
+	ax25_for_each(s, &ax25_list) {
+		if (s->sk && s->sk->sk_type != SOCK_SEQPACKET)
+			continue;
+		if (s->ax25_dev == NULL)
+			continue;
+		if (ax25cmp(&s->source_addr, src_addr) == 0 && ax25cmp(&s->dest_addr, dest_addr) == 0 && s->ax25_dev->dev == dev) {
+			if (digi != NULL && digi->ndigi != 0) {
+				if (s->digipeat == NULL)
+					continue;
+				if (ax25digicmp(s->digipeat, digi) != 0)
+					continue;
+			} else {
+				if (s->digipeat != NULL && s->digipeat->ndigi != 0)
+					continue;
+			}
+			ax25_cb_hold(s);
+			spin_unlock_bh(&ax25_list_lock);
+
+			return s;
+		}
+	}
+	spin_unlock_bh(&ax25_list_lock);
+
+	return NULL;
+}
+
+EXPORT_SYMBOL(ax25_find_cb);
+
+void ax25_send_to_raw(ax25_address *addr, struct sk_buff *skb, int proto)
+{
+	ax25_cb *s;
+	struct sk_buff *copy;
+
+	spin_lock(&ax25_list_lock);
+	ax25_for_each(s, &ax25_list) {
+		if (s->sk != NULL && ax25cmp(&s->source_addr, addr) == 0 &&
+		    s->sk->sk_type == SOCK_RAW &&
+		    s->sk->sk_protocol == proto &&
+		    s->ax25_dev->dev == skb->dev &&
+		    atomic_read(&s->sk->sk_rmem_alloc) <= s->sk->sk_rcvbuf) {
+			if ((copy = skb_clone(skb, GFP_ATOMIC)) == NULL)
+				continue;
+			if (sock_queue_rcv_skb(s->sk, copy) != 0)
+				kfree_skb(copy);
+		}
+	}
+	spin_unlock(&ax25_list_lock);
+}
+
+/*
+ *	Deferred destroy.
+ */
+void ax25_destroy_socket(ax25_cb *);
+
+/*
+ *	Handler for deferred kills.
+ */
+static void ax25_destroy_timer(struct timer_list *t)
+{
+	ax25_cb *ax25 = from_timer(ax25, t, dtimer);
+	struct sock *sk;
+
+	sk=ax25->sk;
+
+	bh_lock_sock(sk);
+	sock_hold(sk);
+	ax25_destroy_socket(ax25);
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+/*
+ *	This is called from user mode and the timers. Thus it protects itself
+ *	against interrupt users but doesn't worry about being called during
+ *	work. Once it is removed from the queue no interrupt or bottom half
+ *	will touch it and we are (fairly 8-) ) safe.
+ */
+void ax25_destroy_socket(ax25_cb *ax25)
+{
+	struct sk_buff *skb;
+
+	ax25_cb_del(ax25);
+
+	ax25_stop_heartbeat(ax25);
+	ax25_stop_t1timer(ax25);
+	ax25_stop_t2timer(ax25);
+	ax25_stop_t3timer(ax25);
+	ax25_stop_idletimer(ax25);
+
+	ax25_clear_queues(ax25);	/* Flush the queues */
+
+	if (ax25->sk != NULL) {
+		while ((skb = skb_dequeue(&ax25->sk->sk_receive_queue)) != NULL) {
+			if (skb->sk != ax25->sk) {
+				/* A pending connection */
+				ax25_cb *sax25 = sk_to_ax25(skb->sk);
+
+				/* Queue the unaccepted socket for death */
+				sock_orphan(skb->sk);
+
+				/* 9A4GL: hack to release unaccepted sockets */
+				skb->sk->sk_state = TCP_LISTEN;
+
+				ax25_start_heartbeat(sax25);
+				sax25->state = AX25_STATE_0;
+			}
+
+			kfree_skb(skb);
+		}
+		skb_queue_purge(&ax25->sk->sk_write_queue);
+	}
+
+	if (ax25->sk != NULL) {
+		if (sk_has_allocations(ax25->sk)) {
+			/* Defer: outstanding buffers */
+			timer_setup(&ax25->dtimer, ax25_destroy_timer, 0);
+			ax25->dtimer.expires  = jiffies + 2 * HZ;
+			add_timer(&ax25->dtimer);
+		} else {
+			struct sock *sk=ax25->sk;
+			ax25->sk=NULL;
+			sock_put(sk);
+		}
+	} else {
+		ax25_cb_put(ax25);
+	}
+}
+
+/*
+ * dl1bke 960311: set parameters for existing AX.25 connections,
+ *		  includes a KILL command to abort any connection.
+ *		  VERY useful for debugging ;-)
+ */
+static int ax25_ctl_ioctl(const unsigned int cmd, void __user *arg)
+{
+	struct ax25_ctl_struct ax25_ctl;
+	ax25_digi digi;
+	ax25_dev *ax25_dev;
+	ax25_cb *ax25;
+	unsigned int k;
+	int ret = 0;
+
+	if (copy_from_user(&ax25_ctl, arg, sizeof(ax25_ctl)))
+		return -EFAULT;
+
+	if (ax25_ctl.digi_count > AX25_MAX_DIGIS)
+		return -EINVAL;
+
+	if (ax25_ctl.arg > ULONG_MAX / HZ && ax25_ctl.cmd != AX25_KILL)
+		return -EINVAL;
+
+	ax25_dev = ax25_addr_ax25dev(&ax25_ctl.port_addr);
+	if (!ax25_dev)
+		return -ENODEV;
+
+	digi.ndigi = ax25_ctl.digi_count;
+	for (k = 0; k < digi.ndigi; k++)
+		digi.calls[k] = ax25_ctl.digi_addr[k];
+
+	ax25 = ax25_find_cb(&ax25_ctl.source_addr, &ax25_ctl.dest_addr, &digi, ax25_dev->dev);
+	if (!ax25) {
+		ax25_dev_put(ax25_dev);
+		return -ENOTCONN;
+	}
+
+	switch (ax25_ctl.cmd) {
+	case AX25_KILL:
+		ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+#ifdef CONFIG_AX25_DAMA_SLAVE
+		if (ax25_dev->dama.slave && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
+			ax25_dama_off(ax25);
+#endif
+		ax25_disconnect(ax25, ENETRESET);
+		break;
+
+	case AX25_WINDOW:
+		if (ax25->modulus == AX25_MODULUS) {
+			if (ax25_ctl.arg < 1 || ax25_ctl.arg > 7)
+				goto einval_put;
+		} else {
+			if (ax25_ctl.arg < 1 || ax25_ctl.arg > 63)
+				goto einval_put;
+		}
+		ax25->window = ax25_ctl.arg;
+		break;
+
+	case AX25_T1:
+		if (ax25_ctl.arg < 1 || ax25_ctl.arg > ULONG_MAX / HZ)
+			goto einval_put;
+		ax25->rtt = (ax25_ctl.arg * HZ) / 2;
+		ax25->t1  = ax25_ctl.arg * HZ;
+		break;
+
+	case AX25_T2:
+		if (ax25_ctl.arg < 1 || ax25_ctl.arg > ULONG_MAX / HZ)
+			goto einval_put;
+		ax25->t2 = ax25_ctl.arg * HZ;
+		break;
+
+	case AX25_N2:
+		if (ax25_ctl.arg < 1 || ax25_ctl.arg > 31)
+			goto einval_put;
+		ax25->n2count = 0;
+		ax25->n2 = ax25_ctl.arg;
+		break;
+
+	case AX25_T3:
+		if (ax25_ctl.arg > ULONG_MAX / HZ)
+			goto einval_put;
+		ax25->t3 = ax25_ctl.arg * HZ;
+		break;
+
+	case AX25_IDLE:
+		if (ax25_ctl.arg > ULONG_MAX / (60 * HZ))
+			goto einval_put;
+
+		ax25->idle = ax25_ctl.arg * 60 * HZ;
+		break;
+
+	case AX25_PACLEN:
+		if (ax25_ctl.arg < 16 || ax25_ctl.arg > 65535)
+			goto einval_put;
+		ax25->paclen = ax25_ctl.arg;
+		break;
+
+	default:
+		goto einval_put;
+	  }
+
+out_put:
+	ax25_dev_put(ax25_dev);
+	ax25_cb_put(ax25);
+	return ret;
+
+einval_put:
+	ret = -EINVAL;
+	goto out_put;
+}
+
+static void ax25_fillin_cb_from_dev(ax25_cb *ax25, ax25_dev *ax25_dev)
+{
+	ax25->rtt     = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_T1]) / 2;
+	ax25->t1      = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_T1]);
+	ax25->t2      = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_T2]);
+	ax25->t3      = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_T3]);
+	ax25->n2      = ax25_dev->values[AX25_VALUES_N2];
+	ax25->paclen  = ax25_dev->values[AX25_VALUES_PACLEN];
+	ax25->idle    = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_IDLE]);
+	ax25->backoff = ax25_dev->values[AX25_VALUES_BACKOFF];
+
+	if (ax25_dev->values[AX25_VALUES_AXDEFMODE]) {
+		ax25->modulus = AX25_EMODULUS;
+		ax25->window  = ax25_dev->values[AX25_VALUES_EWINDOW];
+	} else {
+		ax25->modulus = AX25_MODULUS;
+		ax25->window  = ax25_dev->values[AX25_VALUES_WINDOW];
+	}
+}
+
+/*
+ *	Fill in a created AX.25 created control block with the default
+ *	values for a particular device.
+ */
+void ax25_fillin_cb(ax25_cb *ax25, ax25_dev *ax25_dev)
+{
+	ax25->ax25_dev = ax25_dev;
+
+	if (ax25->ax25_dev != NULL) {
+		ax25_fillin_cb_from_dev(ax25, ax25_dev);
+		return;
+	}
+
+	/*
+	 * No device, use kernel / AX.25 spec default values
+	 */
+	ax25->rtt     = msecs_to_jiffies(AX25_DEF_T1) / 2;
+	ax25->t1      = msecs_to_jiffies(AX25_DEF_T1);
+	ax25->t2      = msecs_to_jiffies(AX25_DEF_T2);
+	ax25->t3      = msecs_to_jiffies(AX25_DEF_T3);
+	ax25->n2      = AX25_DEF_N2;
+	ax25->paclen  = AX25_DEF_PACLEN;
+	ax25->idle    = msecs_to_jiffies(AX25_DEF_IDLE);
+	ax25->backoff = AX25_DEF_BACKOFF;
+
+	if (AX25_DEF_AXDEFMODE) {
+		ax25->modulus = AX25_EMODULUS;
+		ax25->window  = AX25_DEF_EWINDOW;
+	} else {
+		ax25->modulus = AX25_MODULUS;
+		ax25->window  = AX25_DEF_WINDOW;
+	}
+}
+
+/*
+ * Create an empty AX.25 control block.
+ */
+ax25_cb *ax25_create_cb(void)
+{
+	ax25_cb *ax25;
+
+	if ((ax25 = kzalloc(sizeof(*ax25), GFP_ATOMIC)) == NULL)
+		return NULL;
+
+	refcount_set(&ax25->refcount, 1);
+
+	skb_queue_head_init(&ax25->write_queue);
+	skb_queue_head_init(&ax25->frag_queue);
+	skb_queue_head_init(&ax25->ack_queue);
+	skb_queue_head_init(&ax25->reseq_queue);
+
+	ax25_setup_timers(ax25);
+
+	ax25_fillin_cb(ax25, NULL);
+
+	ax25->state = AX25_STATE_0;
+
+	return ax25;
+}
+
+/*
+ *	Handling for system calls applied via the various interfaces to an
+ *	AX25 socket object
+ */
+
+static int ax25_setsockopt(struct socket *sock, int level, int optname,
+		sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	ax25_cb *ax25;
+	struct net_device *dev;
+	char devname[IFNAMSIZ];
+	unsigned int opt;
+	int res = 0;
+
+	if (level != SOL_AX25)
+		return -ENOPROTOOPT;
+
+	if (optlen < sizeof(unsigned int))
+		return -EINVAL;
+
+	if (copy_from_sockptr(&opt, optval, sizeof(unsigned int)))
+		return -EFAULT;
+
+	lock_sock(sk);
+	ax25 = sk_to_ax25(sk);
+
+	switch (optname) {
+	case AX25_WINDOW:
+		if (ax25->modulus == AX25_MODULUS) {
+			if (opt < 1 || opt > 7) {
+				res = -EINVAL;
+				break;
+			}
+		} else {
+			if (opt < 1 || opt > 63) {
+				res = -EINVAL;
+				break;
+			}
+		}
+		ax25->window = opt;
+		break;
+
+	case AX25_T1:
+		if (opt < 1 || opt > UINT_MAX / HZ) {
+			res = -EINVAL;
+			break;
+		}
+		ax25->rtt = (opt * HZ) >> 1;
+		ax25->t1  = opt * HZ;
+		break;
+
+	case AX25_T2:
+		if (opt < 1 || opt > UINT_MAX / HZ) {
+			res = -EINVAL;
+			break;
+		}
+		ax25->t2 = opt * HZ;
+		break;
+
+	case AX25_N2:
+		if (opt < 1 || opt > 31) {
+			res = -EINVAL;
+			break;
+		}
+		ax25->n2 = opt;
+		break;
+
+	case AX25_T3:
+		if (opt < 1 || opt > UINT_MAX / HZ) {
+			res = -EINVAL;
+			break;
+		}
+		ax25->t3 = opt * HZ;
+		break;
+
+	case AX25_IDLE:
+		if (opt > UINT_MAX / (60 * HZ)) {
+			res = -EINVAL;
+			break;
+		}
+		ax25->idle = opt * 60 * HZ;
+		break;
+
+	case AX25_BACKOFF:
+		if (opt > 2) {
+			res = -EINVAL;
+			break;
+		}
+		ax25->backoff = opt;
+		break;
+
+	case AX25_EXTSEQ:
+		ax25->modulus = opt ? AX25_EMODULUS : AX25_MODULUS;
+		break;
+
+	case AX25_PIDINCL:
+		ax25->pidincl = opt ? 1 : 0;
+		break;
+
+	case AX25_IAMDIGI:
+		ax25->iamdigi = opt ? 1 : 0;
+		break;
+
+	case AX25_PACLEN:
+		if (opt < 16 || opt > 65535) {
+			res = -EINVAL;
+			break;
+		}
+		ax25->paclen = opt;
+		break;
+
+	case SO_BINDTODEVICE:
+		if (optlen > IFNAMSIZ - 1)
+			optlen = IFNAMSIZ - 1;
+
+		memset(devname, 0, sizeof(devname));
+
+		if (copy_from_sockptr(devname, optval, optlen)) {
+			res = -EFAULT;
+			break;
+		}
+
+		if (sk->sk_type == SOCK_SEQPACKET &&
+		   (sock->state != SS_UNCONNECTED ||
+		    sk->sk_state == TCP_LISTEN)) {
+			res = -EADDRNOTAVAIL;
+			break;
+		}
+
+		rtnl_lock();
+		dev = __dev_get_by_name(&init_net, devname);
+		if (!dev) {
+			rtnl_unlock();
+			res = -ENODEV;
+			break;
+		}
+
+		ax25->ax25_dev = ax25_dev_ax25dev(dev);
+		if (!ax25->ax25_dev) {
+			rtnl_unlock();
+			res = -ENODEV;
+			break;
+		}
+		ax25_fillin_cb(ax25, ax25->ax25_dev);
+		rtnl_unlock();
+		break;
+
+	default:
+		res = -ENOPROTOOPT;
+	}
+	release_sock(sk);
+
+	return res;
+}
+
+static int ax25_getsockopt(struct socket *sock, int level, int optname,
+	char __user *optval, int __user *optlen)
+{
+	struct sock *sk = sock->sk;
+	ax25_cb *ax25;
+	struct ax25_dev *ax25_dev;
+	char devname[IFNAMSIZ];
+	void *valptr;
+	int val = 0;
+	int maxlen, length;
+
+	if (level != SOL_AX25)
+		return -ENOPROTOOPT;
+
+	if (get_user(maxlen, optlen))
+		return -EFAULT;
+
+	if (maxlen < 1)
+		return -EFAULT;
+
+	valptr = (void *) &val;
+	length = min_t(unsigned int, maxlen, sizeof(int));
+
+	lock_sock(sk);
+	ax25 = sk_to_ax25(sk);
+
+	switch (optname) {
+	case AX25_WINDOW:
+		val = ax25->window;
+		break;
+
+	case AX25_T1:
+		val = ax25->t1 / HZ;
+		break;
+
+	case AX25_T2:
+		val = ax25->t2 / HZ;
+		break;
+
+	case AX25_N2:
+		val = ax25->n2;
+		break;
+
+	case AX25_T3:
+		val = ax25->t3 / HZ;
+		break;
+
+	case AX25_IDLE:
+		val = ax25->idle / (60 * HZ);
+		break;
+
+	case AX25_BACKOFF:
+		val = ax25->backoff;
+		break;
+
+	case AX25_EXTSEQ:
+		val = (ax25->modulus == AX25_EMODULUS);
+		break;
+
+	case AX25_PIDINCL:
+		val = ax25->pidincl;
+		break;
+
+	case AX25_IAMDIGI:
+		val = ax25->iamdigi;
+		break;
+
+	case AX25_PACLEN:
+		val = ax25->paclen;
+		break;
+
+	case SO_BINDTODEVICE:
+		ax25_dev = ax25->ax25_dev;
+
+		if (ax25_dev != NULL && ax25_dev->dev != NULL) {
+			strscpy(devname, ax25_dev->dev->name, sizeof(devname));
+			length = strlen(devname) + 1;
+		} else {
+			*devname = '\0';
+			length = 1;
+		}
+
+		valptr = (void *) devname;
+		break;
+
+	default:
+		release_sock(sk);
+		return -ENOPROTOOPT;
+	}
+	release_sock(sk);
+
+	if (put_user(length, optlen))
+		return -EFAULT;
+
+	return copy_to_user(optval, valptr, length) ? -EFAULT : 0;
+}
+
+static int ax25_listen(struct socket *sock, int backlog)
+{
+	struct sock *sk = sock->sk;
+	int res = 0;
+
+	lock_sock(sk);
+	if (sk->sk_type == SOCK_SEQPACKET && sk->sk_state != TCP_LISTEN) {
+		sk->sk_max_ack_backlog = backlog;
+		sk->sk_state           = TCP_LISTEN;
+		goto out;
+	}
+	res = -EOPNOTSUPP;
+
+out:
+	release_sock(sk);
+
+	return res;
+}
+
+/*
+ * XXX: when creating ax25_sock we should update the .obj_size setting
+ * below.
+ */
+static struct proto ax25_proto = {
+	.name	  = "AX25",
+	.owner	  = THIS_MODULE,
+	.obj_size = sizeof(struct ax25_sock),
+};
+
+static int ax25_create(struct net *net, struct socket *sock, int protocol,
+		       int kern)
+{
+	struct sock *sk;
+	ax25_cb *ax25;
+
+	if (protocol < 0 || protocol > U8_MAX)
+		return -EINVAL;
+
+	if (!net_eq(net, &init_net))
+		return -EAFNOSUPPORT;
+
+	switch (sock->type) {
+	case SOCK_DGRAM:
+		if (protocol == 0 || protocol == PF_AX25)
+			protocol = AX25_P_TEXT;
+		break;
+
+	case SOCK_SEQPACKET:
+		switch (protocol) {
+		case 0:
+		case PF_AX25:	/* For CLX */
+			protocol = AX25_P_TEXT;
+			break;
+		case AX25_P_SEGMENT:
+#ifdef CONFIG_INET
+		case AX25_P_ARP:
+		case AX25_P_IP:
+#endif
+#ifdef CONFIG_NETROM
+		case AX25_P_NETROM:
+#endif
+#ifdef CONFIG_ROSE
+		case AX25_P_ROSE:
+#endif
+			return -ESOCKTNOSUPPORT;
+#ifdef CONFIG_NETROM_MODULE
+		case AX25_P_NETROM:
+			if (ax25_protocol_is_registered(AX25_P_NETROM))
+				return -ESOCKTNOSUPPORT;
+			break;
+#endif
+#ifdef CONFIG_ROSE_MODULE
+		case AX25_P_ROSE:
+			if (ax25_protocol_is_registered(AX25_P_ROSE))
+				return -ESOCKTNOSUPPORT;
+			break;
+#endif
+		default:
+			break;
+		}
+		break;
+
+	case SOCK_RAW:
+		if (!capable(CAP_NET_RAW))
+			return -EPERM;
+		break;
+	default:
+		return -ESOCKTNOSUPPORT;
+	}
+
+	sk = sk_alloc(net, PF_AX25, GFP_ATOMIC, &ax25_proto, kern);
+	if (sk == NULL)
+		return -ENOMEM;
+
+	ax25 = ax25_sk(sk)->cb = ax25_create_cb();
+	if (!ax25) {
+		sk_free(sk);
+		return -ENOMEM;
+	}
+
+	sock_init_data(sock, sk);
+
+	sk->sk_destruct = ax25_free_sock;
+	sock->ops    = &ax25_proto_ops;
+	sk->sk_protocol = protocol;
+
+	ax25->sk    = sk;
+
+	return 0;
+}
+
+struct sock *ax25_make_new(struct sock *osk, struct ax25_dev *ax25_dev)
+{
+	struct sock *sk;
+	ax25_cb *ax25, *oax25;
+
+	sk = sk_alloc(sock_net(osk), PF_AX25, GFP_ATOMIC, osk->sk_prot, 0);
+	if (sk == NULL)
+		return NULL;
+
+	if ((ax25 = ax25_create_cb()) == NULL) {
+		sk_free(sk);
+		return NULL;
+	}
+
+	switch (osk->sk_type) {
+	case SOCK_DGRAM:
+		break;
+	case SOCK_SEQPACKET:
+		break;
+	default:
+		sk_free(sk);
+		ax25_cb_put(ax25);
+		return NULL;
+	}
+
+	sock_init_data(NULL, sk);
+
+	sk->sk_type     = osk->sk_type;
+	sk->sk_priority = osk->sk_priority;
+	sk->sk_protocol = osk->sk_protocol;
+	sk->sk_rcvbuf   = osk->sk_rcvbuf;
+	sk->sk_sndbuf   = osk->sk_sndbuf;
+	sk->sk_state    = TCP_ESTABLISHED;
+	sock_copy_flags(sk, osk);
+
+	oax25 = sk_to_ax25(osk);
+
+	ax25->modulus = oax25->modulus;
+	ax25->backoff = oax25->backoff;
+	ax25->pidincl = oax25->pidincl;
+	ax25->iamdigi = oax25->iamdigi;
+	ax25->rtt     = oax25->rtt;
+	ax25->t1      = oax25->t1;
+	ax25->t2      = oax25->t2;
+	ax25->t3      = oax25->t3;
+	ax25->n2      = oax25->n2;
+	ax25->idle    = oax25->idle;
+	ax25->paclen  = oax25->paclen;
+	ax25->window  = oax25->window;
+
+	ax25->ax25_dev    = ax25_dev;
+	ax25->source_addr = oax25->source_addr;
+
+	if (oax25->digipeat != NULL) {
+		ax25->digipeat = kmemdup(oax25->digipeat, sizeof(ax25_digi),
+					 GFP_ATOMIC);
+		if (ax25->digipeat == NULL) {
+			sk_free(sk);
+			ax25_cb_put(ax25);
+			return NULL;
+		}
+	}
+
+	ax25_sk(sk)->cb = ax25;
+	sk->sk_destruct = ax25_free_sock;
+	ax25->sk    = sk;
+
+	return sk;
+}
+
+static int ax25_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	ax25_cb *ax25;
+	ax25_dev *ax25_dev;
+
+	if (sk == NULL)
+		return 0;
+
+	sock_hold(sk);
+	lock_sock(sk);
+	sock_orphan(sk);
+	ax25 = sk_to_ax25(sk);
+	ax25_dev = ax25->ax25_dev;
+
+	if (sk->sk_type == SOCK_SEQPACKET) {
+		switch (ax25->state) {
+		case AX25_STATE_0:
+			if (!sock_flag(ax25->sk, SOCK_DEAD)) {
+				release_sock(sk);
+				ax25_disconnect(ax25, 0);
+				lock_sock(sk);
+			}
+			ax25_destroy_socket(ax25);
+			break;
+
+		case AX25_STATE_1:
+		case AX25_STATE_2:
+			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+			release_sock(sk);
+			ax25_disconnect(ax25, 0);
+			lock_sock(sk);
+			if (!sock_flag(ax25->sk, SOCK_DESTROY))
+				ax25_destroy_socket(ax25);
+			break;
+
+		case AX25_STATE_3:
+		case AX25_STATE_4:
+			ax25_clear_queues(ax25);
+			ax25->n2count = 0;
+
+			switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+			case AX25_PROTO_STD_SIMPLEX:
+			case AX25_PROTO_STD_DUPLEX:
+				ax25_send_control(ax25,
+						  AX25_DISC,
+						  AX25_POLLON,
+						  AX25_COMMAND);
+				ax25_stop_t2timer(ax25);
+				ax25_stop_t3timer(ax25);
+				ax25_stop_idletimer(ax25);
+				break;
+#ifdef CONFIG_AX25_DAMA_SLAVE
+			case AX25_PROTO_DAMA_SLAVE:
+				ax25_stop_t3timer(ax25);
+				ax25_stop_idletimer(ax25);
+				break;
+#endif
+			}
+			ax25_calculate_t1(ax25);
+			ax25_start_t1timer(ax25);
+			ax25->state = AX25_STATE_2;
+			sk->sk_state                = TCP_CLOSE;
+			sk->sk_shutdown            |= SEND_SHUTDOWN;
+			sk->sk_state_change(sk);
+			sock_set_flag(sk, SOCK_DESTROY);
+			break;
+
+		default:
+			break;
+		}
+	} else {
+		sk->sk_state     = TCP_CLOSE;
+		sk->sk_shutdown |= SEND_SHUTDOWN;
+		sk->sk_state_change(sk);
+		ax25_destroy_socket(ax25);
+	}
+	if (ax25_dev) {
+		if (!ax25_dev->device_up) {
+			del_timer_sync(&ax25->timer);
+			del_timer_sync(&ax25->t1timer);
+			del_timer_sync(&ax25->t2timer);
+			del_timer_sync(&ax25->t3timer);
+			del_timer_sync(&ax25->idletimer);
+		}
+		netdev_put(ax25_dev->dev, &ax25->dev_tracker);
+		ax25_dev_put(ax25_dev);
+	}
+
+	sock->sk   = NULL;
+	release_sock(sk);
+	sock_put(sk);
+
+	return 0;
+}
+
+/*
+ *	We support a funny extension here so you can (as root) give any callsign
+ *	digipeated via a local address as source. This hack is obsolete now
+ *	that we've implemented support for SO_BINDTODEVICE. It is however small
+ *	and trivially backward compatible.
+ */
+static int ax25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct sock *sk = sock->sk;
+	struct full_sockaddr_ax25 *addr = (struct full_sockaddr_ax25 *)uaddr;
+	ax25_dev *ax25_dev = NULL;
+	ax25_uid_assoc *user;
+	ax25_address call;
+	ax25_cb *ax25;
+	int err = 0;
+
+	if (addr_len != sizeof(struct sockaddr_ax25) &&
+	    addr_len != sizeof(struct full_sockaddr_ax25))
+		/* support for old structure may go away some time
+		 * ax25_bind(): uses old (6 digipeater) socket structure.
+		 */
+		if ((addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * 6) ||
+		    (addr_len > sizeof(struct full_sockaddr_ax25)))
+			return -EINVAL;
+
+	if (addr->fsa_ax25.sax25_family != AF_AX25)
+		return -EINVAL;
+
+	user = ax25_findbyuid(current_euid());
+	if (user) {
+		call = user->call;
+		ax25_uid_put(user);
+	} else {
+		if (ax25_uid_policy && !capable(CAP_NET_ADMIN))
+			return -EACCES;
+
+		call = addr->fsa_ax25.sax25_call;
+	}
+
+	lock_sock(sk);
+
+	ax25 = sk_to_ax25(sk);
+	if (!sock_flag(sk, SOCK_ZAPPED)) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	ax25->source_addr = call;
+
+	/*
+	 * User already set interface with SO_BINDTODEVICE
+	 */
+	if (ax25->ax25_dev != NULL)
+		goto done;
+
+	if (addr_len > sizeof(struct sockaddr_ax25) && addr->fsa_ax25.sax25_ndigis == 1) {
+		if (ax25cmp(&addr->fsa_digipeater[0], &null_ax25_address) != 0 &&
+		    (ax25_dev = ax25_addr_ax25dev(&addr->fsa_digipeater[0])) == NULL) {
+			err = -EADDRNOTAVAIL;
+			goto out;
+		}
+	} else {
+		if ((ax25_dev = ax25_addr_ax25dev(&addr->fsa_ax25.sax25_call)) == NULL) {
+			err = -EADDRNOTAVAIL;
+			goto out;
+		}
+	}
+
+	if (ax25_dev) {
+		ax25_fillin_cb(ax25, ax25_dev);
+		netdev_hold(ax25_dev->dev, &ax25->dev_tracker, GFP_ATOMIC);
+	}
+
+done:
+	ax25_cb_add(ax25);
+	sock_reset_flag(sk, SOCK_ZAPPED);
+
+out:
+	release_sock(sk);
+
+	return err;
+}
+
+/*
+ *	FIXME: nonblock behaviour looks like it may have a bug.
+ */
+static int __must_check ax25_connect(struct socket *sock,
+	struct sockaddr *uaddr, int addr_len, int flags)
+{
+	struct sock *sk = sock->sk;
+	ax25_cb *ax25 = sk_to_ax25(sk), *ax25t;
+	struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)uaddr;
+	ax25_digi *digi = NULL;
+	int ct = 0, err = 0;
+
+	/*
+	 * some sanity checks. code further down depends on this
+	 */
+
+	if (addr_len == sizeof(struct sockaddr_ax25))
+		/* support for this will go away in early 2.5.x
+		 * ax25_connect(): uses obsolete socket structure
+		 */
+		;
+	else if (addr_len != sizeof(struct full_sockaddr_ax25))
+		/* support for old structure may go away some time
+		 * ax25_connect(): uses old (6 digipeater) socket structure.
+		 */
+		if ((addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * 6) ||
+		    (addr_len > sizeof(struct full_sockaddr_ax25)))
+			return -EINVAL;
+
+
+	if (fsa->fsa_ax25.sax25_family != AF_AX25)
+		return -EINVAL;
+
+	lock_sock(sk);
+
+	/* deal with restarts */
+	if (sock->state == SS_CONNECTING) {
+		switch (sk->sk_state) {
+		case TCP_SYN_SENT: /* still trying */
+			err = -EINPROGRESS;
+			goto out_release;
+
+		case TCP_ESTABLISHED: /* connection established */
+			sock->state = SS_CONNECTED;
+			goto out_release;
+
+		case TCP_CLOSE: /* connection refused */
+			sock->state = SS_UNCONNECTED;
+			err = -ECONNREFUSED;
+			goto out_release;
+		}
+	}
+
+	if (sk->sk_state == TCP_ESTABLISHED && sk->sk_type == SOCK_SEQPACKET) {
+		err = -EISCONN;	/* No reconnect on a seqpacket socket */
+		goto out_release;
+	}
+
+	sk->sk_state   = TCP_CLOSE;
+	sock->state = SS_UNCONNECTED;
+
+	kfree(ax25->digipeat);
+	ax25->digipeat = NULL;
+
+	/*
+	 *	Handle digi-peaters to be used.
+	 */
+	if (addr_len > sizeof(struct sockaddr_ax25) &&
+	    fsa->fsa_ax25.sax25_ndigis != 0) {
+		/* Valid number of digipeaters ? */
+		if (fsa->fsa_ax25.sax25_ndigis < 1 ||
+		    fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS ||
+		    addr_len < sizeof(struct sockaddr_ax25) +
+		    sizeof(ax25_address) * fsa->fsa_ax25.sax25_ndigis) {
+			err = -EINVAL;
+			goto out_release;
+		}
+
+		if ((digi = kmalloc(sizeof(ax25_digi), GFP_KERNEL)) == NULL) {
+			err = -ENOBUFS;
+			goto out_release;
+		}
+
+		digi->ndigi      = fsa->fsa_ax25.sax25_ndigis;
+		digi->lastrepeat = -1;
+
+		while (ct < fsa->fsa_ax25.sax25_ndigis) {
+			if ((fsa->fsa_digipeater[ct].ax25_call[6] &
+			     AX25_HBIT) && ax25->iamdigi) {
+				digi->repeated[ct] = 1;
+				digi->lastrepeat   = ct;
+			} else {
+				digi->repeated[ct] = 0;
+			}
+			digi->calls[ct] = fsa->fsa_digipeater[ct];
+			ct++;
+		}
+	}
+
+	/*
+	 *	Must bind first - autobinding in this may or may not work. If
+	 *	the socket is already bound, check to see if the device has
+	 *	been filled in, error if it hasn't.
+	 */
+	if (sock_flag(sk, SOCK_ZAPPED)) {
+		/* check if we can remove this feature. It is broken. */
+		printk(KERN_WARNING "ax25_connect(): %s uses autobind, please contact jreuter@yaina.de\n",
+			current->comm);
+		if ((err = ax25_rt_autobind(ax25, &fsa->fsa_ax25.sax25_call)) < 0) {
+			kfree(digi);
+			goto out_release;
+		}
+
+		ax25_fillin_cb(ax25, ax25->ax25_dev);
+		ax25_cb_add(ax25);
+	} else {
+		if (ax25->ax25_dev == NULL) {
+			kfree(digi);
+			err = -EHOSTUNREACH;
+			goto out_release;
+		}
+	}
+
+	if (sk->sk_type == SOCK_SEQPACKET &&
+	    (ax25t=ax25_find_cb(&ax25->source_addr, &fsa->fsa_ax25.sax25_call, digi,
+			 ax25->ax25_dev->dev))) {
+		kfree(digi);
+		err = -EADDRINUSE;		/* Already such a connection */
+		ax25_cb_put(ax25t);
+		goto out_release;
+	}
+
+	ax25->dest_addr = fsa->fsa_ax25.sax25_call;
+	ax25->digipeat  = digi;
+
+	/* First the easy one */
+	if (sk->sk_type != SOCK_SEQPACKET) {
+		sock->state = SS_CONNECTED;
+		sk->sk_state   = TCP_ESTABLISHED;
+		goto out_release;
+	}
+
+	/* Move to connecting socket, ax.25 lapb WAIT_UA.. */
+	sock->state        = SS_CONNECTING;
+	sk->sk_state          = TCP_SYN_SENT;
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_std_establish_data_link(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		ax25->modulus = AX25_MODULUS;
+		ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+		if (ax25->ax25_dev->dama.slave)
+			ax25_ds_establish_data_link(ax25);
+		else
+			ax25_std_establish_data_link(ax25);
+		break;
+#endif
+	}
+
+	ax25->state = AX25_STATE_1;
+
+	ax25_start_heartbeat(ax25);
+
+	/* Now the loop */
+	if (sk->sk_state != TCP_ESTABLISHED && (flags & O_NONBLOCK)) {
+		err = -EINPROGRESS;
+		goto out_release;
+	}
+
+	if (sk->sk_state == TCP_SYN_SENT) {
+		DEFINE_WAIT(wait);
+
+		for (;;) {
+			prepare_to_wait(sk_sleep(sk), &wait,
+					TASK_INTERRUPTIBLE);
+			if (sk->sk_state != TCP_SYN_SENT)
+				break;
+			if (!signal_pending(current)) {
+				release_sock(sk);
+				schedule();
+				lock_sock(sk);
+				continue;
+			}
+			err = -ERESTARTSYS;
+			break;
+		}
+		finish_wait(sk_sleep(sk), &wait);
+
+		if (err)
+			goto out_release;
+	}
+
+	if (sk->sk_state != TCP_ESTABLISHED) {
+		/* Not in ABM, not in WAIT_UA -> failed */
+		sock->state = SS_UNCONNECTED;
+		err = sock_error(sk);	/* Always set at this point */
+		goto out_release;
+	}
+
+	sock->state = SS_CONNECTED;
+
+	err = 0;
+out_release:
+	release_sock(sk);
+
+	return err;
+}
+
+static int ax25_accept(struct socket *sock, struct socket *newsock, int flags,
+		       bool kern)
+{
+	struct sk_buff *skb;
+	struct sock *newsk;
+	DEFINE_WAIT(wait);
+	struct sock *sk;
+	int err = 0;
+
+	if (sock->state != SS_UNCONNECTED)
+		return -EINVAL;
+
+	if ((sk = sock->sk) == NULL)
+		return -EINVAL;
+
+	lock_sock(sk);
+	if (sk->sk_type != SOCK_SEQPACKET) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	if (sk->sk_state != TCP_LISTEN) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 *	The read queue this time is holding sockets ready to use
+	 *	hooked into the SABM we saved
+	 */
+	for (;;) {
+		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+		skb = skb_dequeue(&sk->sk_receive_queue);
+		if (skb)
+			break;
+
+		if (flags & O_NONBLOCK) {
+			err = -EWOULDBLOCK;
+			break;
+		}
+		if (!signal_pending(current)) {
+			release_sock(sk);
+			schedule();
+			lock_sock(sk);
+			continue;
+		}
+		err = -ERESTARTSYS;
+		break;
+	}
+	finish_wait(sk_sleep(sk), &wait);
+
+	if (err)
+		goto out;
+
+	newsk		 = skb->sk;
+	sock_graft(newsk, newsock);
+
+	/* Now attach up the new socket */
+	kfree_skb(skb);
+	sk_acceptq_removed(sk);
+	newsock->state = SS_CONNECTED;
+
+out:
+	release_sock(sk);
+
+	return err;
+}
+
+static int ax25_getname(struct socket *sock, struct sockaddr *uaddr,
+	int peer)
+{
+	struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)uaddr;
+	struct sock *sk = sock->sk;
+	unsigned char ndigi, i;
+	ax25_cb *ax25;
+	int err = 0;
+
+	memset(fsa, 0, sizeof(*fsa));
+	lock_sock(sk);
+	ax25 = sk_to_ax25(sk);
+
+	if (peer != 0) {
+		if (sk->sk_state != TCP_ESTABLISHED) {
+			err = -ENOTCONN;
+			goto out;
+		}
+
+		fsa->fsa_ax25.sax25_family = AF_AX25;
+		fsa->fsa_ax25.sax25_call   = ax25->dest_addr;
+
+		if (ax25->digipeat != NULL) {
+			ndigi = ax25->digipeat->ndigi;
+			fsa->fsa_ax25.sax25_ndigis = ndigi;
+			for (i = 0; i < ndigi; i++)
+				fsa->fsa_digipeater[i] =
+						ax25->digipeat->calls[i];
+		}
+	} else {
+		fsa->fsa_ax25.sax25_family = AF_AX25;
+		fsa->fsa_ax25.sax25_call   = ax25->source_addr;
+		fsa->fsa_ax25.sax25_ndigis = 1;
+		if (ax25->ax25_dev != NULL) {
+			memcpy(&fsa->fsa_digipeater[0],
+			       ax25->ax25_dev->dev->dev_addr, AX25_ADDR_LEN);
+		} else {
+			fsa->fsa_digipeater[0] = null_ax25_address;
+		}
+	}
+	err = sizeof (struct full_sockaddr_ax25);
+
+out:
+	release_sock(sk);
+
+	return err;
+}
+
+static int ax25_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
+{
+	DECLARE_SOCKADDR(struct sockaddr_ax25 *, usax, msg->msg_name);
+	struct sock *sk = sock->sk;
+	struct sockaddr_ax25 sax;
+	struct sk_buff *skb;
+	ax25_digi dtmp, *dp;
+	ax25_cb *ax25;
+	size_t size;
+	int lv, err, addr_len = msg->msg_namelen;
+
+	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_CMSG_COMPAT))
+		return -EINVAL;
+
+	lock_sock(sk);
+	ax25 = sk_to_ax25(sk);
+
+	if (sock_flag(sk, SOCK_ZAPPED)) {
+		err = -EADDRNOTAVAIL;
+		goto out;
+	}
+
+	if (sk->sk_shutdown & SEND_SHUTDOWN) {
+		send_sig(SIGPIPE, current, 0);
+		err = -EPIPE;
+		goto out;
+	}
+
+	if (ax25->ax25_dev == NULL) {
+		err = -ENETUNREACH;
+		goto out;
+	}
+
+	if (len > ax25->ax25_dev->dev->mtu) {
+		err = -EMSGSIZE;
+		goto out;
+	}
+
+	if (usax != NULL) {
+		if (usax->sax25_family != AF_AX25) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (addr_len == sizeof(struct sockaddr_ax25))
+			/* ax25_sendmsg(): uses obsolete socket structure */
+			;
+		else if (addr_len != sizeof(struct full_sockaddr_ax25))
+			/* support for old structure may go away some time
+			 * ax25_sendmsg(): uses old (6 digipeater)
+			 * socket structure.
+			 */
+			if ((addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * 6) ||
+			    (addr_len > sizeof(struct full_sockaddr_ax25))) {
+				err = -EINVAL;
+				goto out;
+			}
+
+
+		if (addr_len > sizeof(struct sockaddr_ax25) && usax->sax25_ndigis != 0) {
+			int ct           = 0;
+			struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)usax;
+
+			/* Valid number of digipeaters ? */
+			if (usax->sax25_ndigis < 1 ||
+			    usax->sax25_ndigis > AX25_MAX_DIGIS ||
+			    addr_len < sizeof(struct sockaddr_ax25) +
+			    sizeof(ax25_address) * usax->sax25_ndigis) {
+				err = -EINVAL;
+				goto out;
+			}
+
+			dtmp.ndigi      = usax->sax25_ndigis;
+
+			while (ct < usax->sax25_ndigis) {
+				dtmp.repeated[ct] = 0;
+				dtmp.calls[ct]    = fsa->fsa_digipeater[ct];
+				ct++;
+			}
+
+			dtmp.lastrepeat = 0;
+		}
+
+		sax = *usax;
+		if (sk->sk_type == SOCK_SEQPACKET &&
+		    ax25cmp(&ax25->dest_addr, &sax.sax25_call)) {
+			err = -EISCONN;
+			goto out;
+		}
+		if (usax->sax25_ndigis == 0)
+			dp = NULL;
+		else
+			dp = &dtmp;
+	} else {
+		/*
+		 *	FIXME: 1003.1g - if the socket is like this because
+		 *	it has become closed (not started closed) and is VC
+		 *	we ought to SIGPIPE, EPIPE
+		 */
+		if (sk->sk_state != TCP_ESTABLISHED) {
+			err = -ENOTCONN;
+			goto out;
+		}
+		sax.sax25_family = AF_AX25;
+		sax.sax25_call   = ax25->dest_addr;
+		dp = ax25->digipeat;
+	}
+
+	/* Build a packet */
+	/* Assume the worst case */
+	size = len + ax25->ax25_dev->dev->hard_header_len;
+
+	skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT, &err);
+	if (skb == NULL)
+		goto out;
+
+	skb_reserve(skb, size - len);
+
+	/* User data follows immediately after the AX.25 data */
+	if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
+		err = -EFAULT;
+		kfree_skb(skb);
+		goto out;
+	}
+
+	skb_reset_network_header(skb);
+
+	/* Add the PID if one is not supplied by the user in the skb */
+	if (!ax25->pidincl)
+		*(u8 *)skb_push(skb, 1) = sk->sk_protocol;
+
+	if (sk->sk_type == SOCK_SEQPACKET) {
+		/* Connected mode sockets go via the LAPB machine */
+		if (sk->sk_state != TCP_ESTABLISHED) {
+			kfree_skb(skb);
+			err = -ENOTCONN;
+			goto out;
+		}
+
+		/* Shove it onto the queue and kick */
+		ax25_output(ax25, ax25->paclen, skb);
+
+		err = len;
+		goto out;
+	}
+
+	skb_push(skb, 1 + ax25_addr_size(dp));
+
+	/* Building AX.25 Header */
+
+	/* Build an AX.25 header */
+	lv = ax25_addr_build(skb->data, &ax25->source_addr, &sax.sax25_call,
+			     dp, AX25_COMMAND, AX25_MODULUS);
+
+	skb_set_transport_header(skb, lv);
+
+	*skb_transport_header(skb) = AX25_UI;
+
+	/* Datagram frames go straight out of the door as UI */
+	ax25_queue_xmit(skb, ax25->ax25_dev->dev);
+
+	err = len;
+
+out:
+	release_sock(sk);
+
+	return err;
+}
+
+static int ax25_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
+			int flags)
+{
+	struct sock *sk = sock->sk;
+	struct sk_buff *skb, *last;
+	struct sk_buff_head *sk_queue;
+	int copied;
+	int err = 0;
+	int off = 0;
+	long timeo;
+
+	lock_sock(sk);
+	/*
+	 * 	This works for seqpacket too. The receiver has ordered the
+	 *	queue for us! We do one quick check first though
+	 */
+	if (sk->sk_type == SOCK_SEQPACKET && sk->sk_state != TCP_ESTABLISHED) {
+		err =  -ENOTCONN;
+		goto out;
+	}
+
+	/*  We need support for non-blocking reads. */
+	sk_queue = &sk->sk_receive_queue;
+	skb = __skb_try_recv_datagram(sk, sk_queue, flags, &off, &err, &last);
+	/* If no packet is available, release_sock(sk) and try again. */
+	if (!skb) {
+		if (err != -EAGAIN)
+			goto out;
+		release_sock(sk);
+		timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+		while (timeo && !__skb_wait_for_more_packets(sk, sk_queue, &err,
+							     &timeo, last)) {
+			skb = __skb_try_recv_datagram(sk, sk_queue, flags, &off,
+						      &err, &last);
+			if (skb)
+				break;
+
+			if (err != -EAGAIN)
+				goto done;
+		}
+		if (!skb)
+			goto done;
+		lock_sock(sk);
+	}
+
+	if (!sk_to_ax25(sk)->pidincl)
+		skb_pull(skb, 1);		/* Remove PID */
+
+	skb_reset_transport_header(skb);
+	copied = skb->len;
+
+	if (copied > size) {
+		copied = size;
+		msg->msg_flags |= MSG_TRUNC;
+	}
+
+	skb_copy_datagram_msg(skb, 0, msg, copied);
+
+	if (msg->msg_name) {
+		ax25_digi digi;
+		ax25_address src;
+		const unsigned char *mac = skb_mac_header(skb);
+		DECLARE_SOCKADDR(struct sockaddr_ax25 *, sax, msg->msg_name);
+
+		memset(sax, 0, sizeof(struct full_sockaddr_ax25));
+		ax25_addr_parse(mac + 1, skb->data - mac - 1, &src, NULL,
+				&digi, NULL, NULL);
+		sax->sax25_family = AF_AX25;
+		/* We set this correctly, even though we may not let the
+		   application know the digi calls further down (because it
+		   did NOT ask to know them).  This could get political... **/
+		sax->sax25_ndigis = digi.ndigi;
+		sax->sax25_call   = src;
+
+		if (sax->sax25_ndigis != 0) {
+			int ct;
+			struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)sax;
+
+			for (ct = 0; ct < digi.ndigi; ct++)
+				fsa->fsa_digipeater[ct] = digi.calls[ct];
+		}
+		msg->msg_namelen = sizeof(struct full_sockaddr_ax25);
+	}
+
+	skb_free_datagram(sk, skb);
+	err = copied;
+
+out:
+	release_sock(sk);
+
+done:
+	return err;
+}
+
+static int ax25_shutdown(struct socket *sk, int how)
+{
+	/* FIXME - generate DM and RNR states */
+	return -EOPNOTSUPP;
+}
+
+static int ax25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	struct sock *sk = sock->sk;
+	void __user *argp = (void __user *)arg;
+	int res = 0;
+
+	lock_sock(sk);
+	switch (cmd) {
+	case TIOCOUTQ: {
+		long amount;
+
+		amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
+		if (amount < 0)
+			amount = 0;
+		res = put_user(amount, (int __user *)argp);
+		break;
+	}
+
+	case TIOCINQ: {
+		struct sk_buff *skb;
+		long amount = 0L;
+		/* These two are safe on a single CPU system as only user tasks fiddle here */
+		if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
+			amount = skb->len;
+		res = put_user(amount, (int __user *) argp);
+		break;
+	}
+
+	case SIOCAX25ADDUID:	/* Add a uid to the uid/call map table */
+	case SIOCAX25DELUID:	/* Delete a uid from the uid/call map table */
+	case SIOCAX25GETUID: {
+		struct sockaddr_ax25 sax25;
+		if (copy_from_user(&sax25, argp, sizeof(sax25))) {
+			res = -EFAULT;
+			break;
+		}
+		res = ax25_uid_ioctl(cmd, &sax25);
+		break;
+	}
+
+	case SIOCAX25NOUID: {	/* Set the default policy (default/bar) */
+		long amount;
+		if (!capable(CAP_NET_ADMIN)) {
+			res = -EPERM;
+			break;
+		}
+		if (get_user(amount, (long __user *)argp)) {
+			res = -EFAULT;
+			break;
+		}
+		if (amount < 0 || amount > AX25_NOUID_BLOCK) {
+			res = -EINVAL;
+			break;
+		}
+		ax25_uid_policy = amount;
+		res = 0;
+		break;
+	}
+
+	case SIOCADDRT:
+	case SIOCDELRT:
+	case SIOCAX25OPTRT:
+		if (!capable(CAP_NET_ADMIN)) {
+			res = -EPERM;
+			break;
+		}
+		res = ax25_rt_ioctl(cmd, argp);
+		break;
+
+	case SIOCAX25CTLCON:
+		if (!capable(CAP_NET_ADMIN)) {
+			res = -EPERM;
+			break;
+		}
+		res = ax25_ctl_ioctl(cmd, argp);
+		break;
+
+	case SIOCAX25GETINFO:
+	case SIOCAX25GETINFOOLD: {
+		ax25_cb *ax25 = sk_to_ax25(sk);
+		struct ax25_info_struct ax25_info;
+
+		ax25_info.t1        = ax25->t1   / HZ;
+		ax25_info.t2        = ax25->t2   / HZ;
+		ax25_info.t3        = ax25->t3   / HZ;
+		ax25_info.idle      = ax25->idle / (60 * HZ);
+		ax25_info.n2        = ax25->n2;
+		ax25_info.t1timer   = ax25_display_timer(&ax25->t1timer)   / HZ;
+		ax25_info.t2timer   = ax25_display_timer(&ax25->t2timer)   / HZ;
+		ax25_info.t3timer   = ax25_display_timer(&ax25->t3timer)   / HZ;
+		ax25_info.idletimer = ax25_display_timer(&ax25->idletimer) / (60 * HZ);
+		ax25_info.n2count   = ax25->n2count;
+		ax25_info.state     = ax25->state;
+		ax25_info.rcv_q     = sk_rmem_alloc_get(sk);
+		ax25_info.snd_q     = sk_wmem_alloc_get(sk);
+		ax25_info.vs        = ax25->vs;
+		ax25_info.vr        = ax25->vr;
+		ax25_info.va        = ax25->va;
+		ax25_info.vs_max    = ax25->vs; /* reserved */
+		ax25_info.paclen    = ax25->paclen;
+		ax25_info.window    = ax25->window;
+
+		/* old structure? */
+		if (cmd == SIOCAX25GETINFOOLD) {
+			static int warned = 0;
+			if (!warned) {
+				printk(KERN_INFO "%s uses old SIOCAX25GETINFO\n",
+					current->comm);
+				warned=1;
+			}
+
+			if (copy_to_user(argp, &ax25_info, sizeof(struct ax25_info_struct_deprecated))) {
+				res = -EFAULT;
+				break;
+			}
+		} else {
+			if (copy_to_user(argp, &ax25_info, sizeof(struct ax25_info_struct))) {
+				res = -EINVAL;
+				break;
+			}
+		}
+		res = 0;
+		break;
+	}
+
+	case SIOCAX25ADDFWD:
+	case SIOCAX25DELFWD: {
+		struct ax25_fwd_struct ax25_fwd;
+		if (!capable(CAP_NET_ADMIN)) {
+			res = -EPERM;
+			break;
+		}
+		if (copy_from_user(&ax25_fwd, argp, sizeof(ax25_fwd))) {
+			res = -EFAULT;
+			break;
+		}
+		res = ax25_fwd_ioctl(cmd, &ax25_fwd);
+		break;
+	}
+
+	case SIOCGIFADDR:
+	case SIOCSIFADDR:
+	case SIOCGIFDSTADDR:
+	case SIOCSIFDSTADDR:
+	case SIOCGIFBRDADDR:
+	case SIOCSIFBRDADDR:
+	case SIOCGIFNETMASK:
+	case SIOCSIFNETMASK:
+	case SIOCGIFMETRIC:
+	case SIOCSIFMETRIC:
+		res = -EINVAL;
+		break;
+
+	default:
+		res = -ENOIOCTLCMD;
+		break;
+	}
+	release_sock(sk);
+
+	return res;
+}
+
+#ifdef CONFIG_PROC_FS
+
+static void *ax25_info_start(struct seq_file *seq, loff_t *pos)
+	__acquires(ax25_list_lock)
+{
+	spin_lock_bh(&ax25_list_lock);
+	return seq_hlist_start(&ax25_list, *pos);
+}
+
+static void *ax25_info_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	return seq_hlist_next(v, &ax25_list, pos);
+}
+
+static void ax25_info_stop(struct seq_file *seq, void *v)
+	__releases(ax25_list_lock)
+{
+	spin_unlock_bh(&ax25_list_lock);
+}
+
+static int ax25_info_show(struct seq_file *seq, void *v)
+{
+	ax25_cb *ax25 = hlist_entry(v, struct ax25_cb, ax25_node);
+	char buf[11];
+	int k;
+
+
+	/*
+	 * New format:
+	 * magic dev src_addr dest_addr,digi1,digi2,.. st vs vr va t1 t1 t2 t2 t3 t3 idle idle n2 n2 rtt window paclen Snd-Q Rcv-Q inode
+	 */
+
+	seq_printf(seq, "%p %s %s%s ",
+		   ax25,
+		   ax25->ax25_dev == NULL? "???" : ax25->ax25_dev->dev->name,
+		   ax2asc(buf, &ax25->source_addr),
+		   ax25->iamdigi? "*":"");
+	seq_printf(seq, "%s", ax2asc(buf, &ax25->dest_addr));
+
+	for (k=0; (ax25->digipeat != NULL) && (k < ax25->digipeat->ndigi); k++) {
+		seq_printf(seq, ",%s%s",
+			   ax2asc(buf, &ax25->digipeat->calls[k]),
+			   ax25->digipeat->repeated[k]? "*":"");
+	}
+
+	seq_printf(seq, " %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %lu %d %d %lu %d %d",
+		   ax25->state,
+		   ax25->vs, ax25->vr, ax25->va,
+		   ax25_display_timer(&ax25->t1timer) / HZ, ax25->t1 / HZ,
+		   ax25_display_timer(&ax25->t2timer) / HZ, ax25->t2 / HZ,
+		   ax25_display_timer(&ax25->t3timer) / HZ, ax25->t3 / HZ,
+		   ax25_display_timer(&ax25->idletimer) / (60 * HZ),
+		   ax25->idle / (60 * HZ),
+		   ax25->n2count, ax25->n2,
+		   ax25->rtt / HZ,
+		   ax25->window,
+		   ax25->paclen);
+
+	if (ax25->sk != NULL) {
+		seq_printf(seq, " %d %d %lu\n",
+			   sk_wmem_alloc_get(ax25->sk),
+			   sk_rmem_alloc_get(ax25->sk),
+			   sock_i_ino(ax25->sk));
+	} else {
+		seq_puts(seq, " * * *\n");
+	}
+	return 0;
+}
+
+static const struct seq_operations ax25_info_seqops = {
+	.start = ax25_info_start,
+	.next = ax25_info_next,
+	.stop = ax25_info_stop,
+	.show = ax25_info_show,
+};
+#endif
+
+static const struct net_proto_family ax25_family_ops = {
+	.family =	PF_AX25,
+	.create =	ax25_create,
+	.owner	=	THIS_MODULE,
+};
+
+static const struct proto_ops ax25_proto_ops = {
+	.family		= PF_AX25,
+	.owner		= THIS_MODULE,
+	.release	= ax25_release,
+	.bind		= ax25_bind,
+	.connect	= ax25_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= ax25_accept,
+	.getname	= ax25_getname,
+	.poll		= datagram_poll,
+	.ioctl		= ax25_ioctl,
+	.gettstamp	= sock_gettstamp,
+	.listen		= ax25_listen,
+	.shutdown	= ax25_shutdown,
+	.setsockopt	= ax25_setsockopt,
+	.getsockopt	= ax25_getsockopt,
+	.sendmsg	= ax25_sendmsg,
+	.recvmsg	= ax25_recvmsg,
+	.mmap		= sock_no_mmap,
+	.sendpage	= sock_no_sendpage,
+};
+
+/*
+ *	Called by socket.c on kernel start up
+ */
+static struct packet_type ax25_packet_type __read_mostly = {
+	.type	=	cpu_to_be16(ETH_P_AX25),
+	.func	=	ax25_kiss_rcv,
+};
+
+static struct notifier_block ax25_dev_notifier = {
+	.notifier_call = ax25_device_event,
+};
+
+static int __init ax25_init(void)
+{
+	int rc = proto_register(&ax25_proto, 0);
+
+	if (rc != 0)
+		goto out;
+
+	sock_register(&ax25_family_ops);
+	dev_add_pack(&ax25_packet_type);
+	register_netdevice_notifier(&ax25_dev_notifier);
+
+	proc_create_seq("ax25_route", 0444, init_net.proc_net, &ax25_rt_seqops);
+	proc_create_seq("ax25", 0444, init_net.proc_net, &ax25_info_seqops);
+	proc_create_seq("ax25_calls", 0444, init_net.proc_net,
+			&ax25_uid_seqops);
+out:
+	return rc;
+}
+module_init(ax25_init);
+
+
+MODULE_AUTHOR("Jonathan Naylor G4KLX <g4klx@g4klx.demon.co.uk>");
+MODULE_DESCRIPTION("The amateur radio AX.25 link layer protocol");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETPROTO(PF_AX25);
+
+static void __exit ax25_exit(void)
+{
+	remove_proc_entry("ax25_route", init_net.proc_net);
+	remove_proc_entry("ax25", init_net.proc_net);
+	remove_proc_entry("ax25_calls", init_net.proc_net);
+
+	unregister_netdevice_notifier(&ax25_dev_notifier);
+
+	dev_remove_pack(&ax25_packet_type);
+
+	sock_unregister(PF_AX25);
+	proto_unregister(&ax25_proto);
+
+	ax25_rt_free();
+	ax25_uid_free();
+	ax25_dev_free();
+}
+module_exit(ax25_exit);
diff --git a/net/ax25/ax25_addr.c b/net/ax25/ax25_addr.c
new file mode 100644
index 000000000..f68865a4d
--- /dev/null
+++ b/net/ax25/ax25_addr.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+/*
+ * The default broadcast address of an interface is QST-0; the default address
+ * is LINUX-1.  The null address is defined as a callsign of all spaces with
+ * an SSID of zero.
+ */
+
+const ax25_address ax25_bcast =
+	{{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
+const ax25_address ax25_defaddr =
+	{{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, 1 << 1}};
+const ax25_address null_ax25_address =
+	{{' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
+
+EXPORT_SYMBOL_GPL(ax25_bcast);
+EXPORT_SYMBOL_GPL(ax25_defaddr);
+EXPORT_SYMBOL(null_ax25_address);
+
+/*
+ *	ax25 -> ascii conversion
+ */
+char *ax2asc(char *buf, const ax25_address *a)
+{
+	char c, *s;
+	int n;
+
+	for (n = 0, s = buf; n < 6; n++) {
+		c = (a->ax25_call[n] >> 1) & 0x7F;
+
+		if (c != ' ') *s++ = c;
+	}
+
+	*s++ = '-';
+
+	if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
+		*s++ = '1';
+		n -= 10;
+	}
+
+	*s++ = n + '0';
+	*s++ = '\0';
+
+	if (*buf == '\0' || *buf == '-')
+	   return "*";
+
+	return buf;
+
+}
+
+EXPORT_SYMBOL(ax2asc);
+
+/*
+ *	ascii -> ax25 conversion
+ */
+void asc2ax(ax25_address *addr, const char *callsign)
+{
+	const char *s;
+	int n;
+
+	for (s = callsign, n = 0; n < 6; n++) {
+		if (*s != '\0' && *s != '-')
+			addr->ax25_call[n] = *s++;
+		else
+			addr->ax25_call[n] = ' ';
+		addr->ax25_call[n] <<= 1;
+		addr->ax25_call[n] &= 0xFE;
+	}
+
+	if (*s++ == '\0') {
+		addr->ax25_call[6] = 0x00;
+		return;
+	}
+
+	addr->ax25_call[6] = *s++ - '0';
+
+	if (*s != '\0') {
+		addr->ax25_call[6] *= 10;
+		addr->ax25_call[6] += *s++ - '0';
+	}
+
+	addr->ax25_call[6] <<= 1;
+	addr->ax25_call[6] &= 0x1E;
+}
+
+EXPORT_SYMBOL(asc2ax);
+
+/*
+ *	Compare two ax.25 addresses
+ */
+int ax25cmp(const ax25_address *a, const ax25_address *b)
+{
+	int ct = 0;
+
+	while (ct < 6) {
+		if ((a->ax25_call[ct] & 0xFE) != (b->ax25_call[ct] & 0xFE))	/* Clean off repeater bits */
+			return 1;
+		ct++;
+	}
+
+	if ((a->ax25_call[ct] & 0x1E) == (b->ax25_call[ct] & 0x1E))	/* SSID without control bit */
+		return 0;
+
+	return 2;			/* Partial match */
+}
+
+EXPORT_SYMBOL(ax25cmp);
+
+/*
+ *	Compare two AX.25 digipeater paths.
+ */
+int ax25digicmp(const ax25_digi *digi1, const ax25_digi *digi2)
+{
+	int i;
+
+	if (digi1->ndigi != digi2->ndigi)
+		return 1;
+
+	if (digi1->lastrepeat != digi2->lastrepeat)
+		return 1;
+
+	for (i = 0; i < digi1->ndigi; i++)
+		if (ax25cmp(&digi1->calls[i], &digi2->calls[i]) != 0)
+			return 1;
+
+	return 0;
+}
+
+/*
+ *	Given an AX.25 address pull of to, from, digi list, command/response and the start of data
+ *
+ */
+const unsigned char *ax25_addr_parse(const unsigned char *buf, int len,
+	ax25_address *src, ax25_address *dest, ax25_digi *digi, int *flags,
+	int *dama)
+{
+	int d = 0;
+
+	if (len < 14) return NULL;
+
+	if (flags != NULL) {
+		*flags = 0;
+
+		if (buf[6] & AX25_CBIT)
+			*flags = AX25_COMMAND;
+		if (buf[13] & AX25_CBIT)
+			*flags = AX25_RESPONSE;
+	}
+
+	if (dama != NULL)
+		*dama = ~buf[13] & AX25_DAMA_FLAG;
+
+	/* Copy to, from */
+	if (dest != NULL)
+		memcpy(dest, buf + 0, AX25_ADDR_LEN);
+	if (src != NULL)
+		memcpy(src,  buf + 7, AX25_ADDR_LEN);
+
+	buf += 2 * AX25_ADDR_LEN;
+	len -= 2 * AX25_ADDR_LEN;
+
+	digi->lastrepeat = -1;
+	digi->ndigi      = 0;
+
+	while (!(buf[-1] & AX25_EBIT)) {
+		if (d >= AX25_MAX_DIGIS)
+			return NULL;
+		if (len < AX25_ADDR_LEN)
+			return NULL;
+
+		memcpy(&digi->calls[d], buf, AX25_ADDR_LEN);
+		digi->ndigi = d + 1;
+
+		if (buf[6] & AX25_HBIT) {
+			digi->repeated[d] = 1;
+			digi->lastrepeat  = d;
+		} else {
+			digi->repeated[d] = 0;
+		}
+
+		buf += AX25_ADDR_LEN;
+		len -= AX25_ADDR_LEN;
+		d++;
+	}
+
+	return buf;
+}
+
+/*
+ *	Assemble an AX.25 header from the bits
+ */
+int ax25_addr_build(unsigned char *buf, const ax25_address *src,
+	const ax25_address *dest, const ax25_digi *d, int flag, int modulus)
+{
+	int len = 0;
+	int ct  = 0;
+
+	memcpy(buf, dest, AX25_ADDR_LEN);
+	buf[6] &= ~(AX25_EBIT | AX25_CBIT);
+	buf[6] |= AX25_SSSID_SPARE;
+
+	if (flag == AX25_COMMAND) buf[6] |= AX25_CBIT;
+
+	buf += AX25_ADDR_LEN;
+	len += AX25_ADDR_LEN;
+
+	memcpy(buf, src, AX25_ADDR_LEN);
+	buf[6] &= ~(AX25_EBIT | AX25_CBIT);
+	buf[6] &= ~AX25_SSSID_SPARE;
+
+	if (modulus == AX25_MODULUS)
+		buf[6] |= AX25_SSSID_SPARE;
+	else
+		buf[6] |= AX25_ESSID_SPARE;
+
+	if (flag == AX25_RESPONSE) buf[6] |= AX25_CBIT;
+
+	/*
+	 *	Fast path the normal digiless path
+	 */
+	if (d == NULL || d->ndigi == 0) {
+		buf[6] |= AX25_EBIT;
+		return 2 * AX25_ADDR_LEN;
+	}
+
+	buf += AX25_ADDR_LEN;
+	len += AX25_ADDR_LEN;
+
+	while (ct < d->ndigi) {
+		memcpy(buf, &d->calls[ct], AX25_ADDR_LEN);
+
+		if (d->repeated[ct])
+			buf[6] |= AX25_HBIT;
+		else
+			buf[6] &= ~AX25_HBIT;
+
+		buf[6] &= ~AX25_EBIT;
+		buf[6] |= AX25_SSSID_SPARE;
+
+		buf += AX25_ADDR_LEN;
+		len += AX25_ADDR_LEN;
+		ct++;
+	}
+
+	buf[-1] |= AX25_EBIT;
+
+	return len;
+}
+
+int ax25_addr_size(const ax25_digi *dp)
+{
+	if (dp == NULL)
+		return 2 * AX25_ADDR_LEN;
+
+	return AX25_ADDR_LEN * (2 + dp->ndigi);
+}
+
+/*
+ *	Reverse Digipeat List. May not pass both parameters as same struct
+ */
+void ax25_digi_invert(const ax25_digi *in, ax25_digi *out)
+{
+	int ct;
+
+	out->ndigi      = in->ndigi;
+	out->lastrepeat = in->ndigi - in->lastrepeat - 2;
+
+	/* Invert the digipeaters */
+	for (ct = 0; ct < in->ndigi; ct++) {
+		out->calls[ct] = in->calls[in->ndigi - ct - 1];
+
+		if (ct <= out->lastrepeat) {
+			out->calls[ct].ax25_call[6] |= AX25_HBIT;
+			out->repeated[ct]            = 1;
+		} else {
+			out->calls[ct].ax25_call[6] &= ~AX25_HBIT;
+			out->repeated[ct]            = 0;
+		}
+	}
+}
diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
new file mode 100644
index 000000000..c5462486d
--- /dev/null
+++ b/net/ax25/ax25_dev.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/slab.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/spinlock.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+
+ax25_dev *ax25_dev_list;
+DEFINE_SPINLOCK(ax25_dev_lock);
+
+ax25_dev *ax25_addr_ax25dev(ax25_address *addr)
+{
+	ax25_dev *ax25_dev, *res = NULL;
+
+	spin_lock_bh(&ax25_dev_lock);
+	for (ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)
+		if (ax25cmp(addr, (const ax25_address *)ax25_dev->dev->dev_addr) == 0) {
+			res = ax25_dev;
+			ax25_dev_hold(ax25_dev);
+		}
+	spin_unlock_bh(&ax25_dev_lock);
+
+	return res;
+}
+
+/*
+ *	This is called when an interface is brought up. These are
+ *	reasonable defaults.
+ */
+void ax25_dev_device_up(struct net_device *dev)
+{
+	ax25_dev *ax25_dev;
+
+	ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_KERNEL);
+	if (!ax25_dev) {
+		printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n");
+		return;
+	}
+
+	refcount_set(&ax25_dev->refcount, 1);
+	dev->ax25_ptr     = ax25_dev;
+	ax25_dev->dev     = dev;
+	netdev_hold(dev, &ax25_dev->dev_tracker, GFP_KERNEL);
+	ax25_dev->forward = NULL;
+	ax25_dev->device_up = true;
+
+	ax25_dev->values[AX25_VALUES_IPDEFMODE] = AX25_DEF_IPDEFMODE;
+	ax25_dev->values[AX25_VALUES_AXDEFMODE] = AX25_DEF_AXDEFMODE;
+	ax25_dev->values[AX25_VALUES_BACKOFF]   = AX25_DEF_BACKOFF;
+	ax25_dev->values[AX25_VALUES_CONMODE]   = AX25_DEF_CONMODE;
+	ax25_dev->values[AX25_VALUES_WINDOW]    = AX25_DEF_WINDOW;
+	ax25_dev->values[AX25_VALUES_EWINDOW]   = AX25_DEF_EWINDOW;
+	ax25_dev->values[AX25_VALUES_T1]        = AX25_DEF_T1;
+	ax25_dev->values[AX25_VALUES_T2]        = AX25_DEF_T2;
+	ax25_dev->values[AX25_VALUES_T3]        = AX25_DEF_T3;
+	ax25_dev->values[AX25_VALUES_IDLE]	= AX25_DEF_IDLE;
+	ax25_dev->values[AX25_VALUES_N2]        = AX25_DEF_N2;
+	ax25_dev->values[AX25_VALUES_PACLEN]	= AX25_DEF_PACLEN;
+	ax25_dev->values[AX25_VALUES_PROTOCOL]  = AX25_DEF_PROTOCOL;
+	ax25_dev->values[AX25_VALUES_DS_TIMEOUT]= AX25_DEF_DS_TIMEOUT;
+
+#if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)
+	ax25_ds_setup_timer(ax25_dev);
+#endif
+
+	spin_lock_bh(&ax25_dev_lock);
+	ax25_dev->next = ax25_dev_list;
+	ax25_dev_list  = ax25_dev;
+	spin_unlock_bh(&ax25_dev_lock);
+	ax25_dev_hold(ax25_dev);
+
+	ax25_register_dev_sysctl(ax25_dev);
+}
+
+void ax25_dev_device_down(struct net_device *dev)
+{
+	ax25_dev *s, *ax25_dev;
+
+	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
+		return;
+
+	ax25_unregister_dev_sysctl(ax25_dev);
+
+	spin_lock_bh(&ax25_dev_lock);
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	ax25_ds_del_timer(ax25_dev);
+#endif
+
+	/*
+	 *	Remove any packet forwarding that points to this device.
+	 */
+	for (s = ax25_dev_list; s != NULL; s = s->next)
+		if (s->forward == dev)
+			s->forward = NULL;
+
+	if ((s = ax25_dev_list) == ax25_dev) {
+		ax25_dev_list = s->next;
+		goto unlock_put;
+	}
+
+	while (s != NULL && s->next != NULL) {
+		if (s->next == ax25_dev) {
+			s->next = ax25_dev->next;
+			goto unlock_put;
+		}
+
+		s = s->next;
+	}
+	spin_unlock_bh(&ax25_dev_lock);
+	dev->ax25_ptr = NULL;
+	ax25_dev_put(ax25_dev);
+	return;
+
+unlock_put:
+	spin_unlock_bh(&ax25_dev_lock);
+	ax25_dev_put(ax25_dev);
+	dev->ax25_ptr = NULL;
+	netdev_put(dev, &ax25_dev->dev_tracker);
+	ax25_dev_put(ax25_dev);
+}
+
+int ax25_fwd_ioctl(unsigned int cmd, struct ax25_fwd_struct *fwd)
+{
+	ax25_dev *ax25_dev, *fwd_dev;
+
+	if ((ax25_dev = ax25_addr_ax25dev(&fwd->port_from)) == NULL)
+		return -EINVAL;
+
+	switch (cmd) {
+	case SIOCAX25ADDFWD:
+		fwd_dev = ax25_addr_ax25dev(&fwd->port_to);
+		if (!fwd_dev) {
+			ax25_dev_put(ax25_dev);
+			return -EINVAL;
+		}
+		if (ax25_dev->forward) {
+			ax25_dev_put(fwd_dev);
+			ax25_dev_put(ax25_dev);
+			return -EINVAL;
+		}
+		ax25_dev->forward = fwd_dev->dev;
+		ax25_dev_put(fwd_dev);
+		ax25_dev_put(ax25_dev);
+		break;
+
+	case SIOCAX25DELFWD:
+		if (!ax25_dev->forward) {
+			ax25_dev_put(ax25_dev);
+			return -EINVAL;
+		}
+		ax25_dev->forward = NULL;
+		ax25_dev_put(ax25_dev);
+		break;
+
+	default:
+		ax25_dev_put(ax25_dev);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+struct net_device *ax25_fwd_dev(struct net_device *dev)
+{
+	ax25_dev *ax25_dev;
+
+	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
+		return dev;
+
+	if (ax25_dev->forward == NULL)
+		return dev;
+
+	return ax25_dev->forward;
+}
+
+/*
+ *	Free all memory associated with device structures.
+ */
+void __exit ax25_dev_free(void)
+{
+	ax25_dev *s, *ax25_dev;
+
+	spin_lock_bh(&ax25_dev_lock);
+	ax25_dev = ax25_dev_list;
+	while (ax25_dev != NULL) {
+		s        = ax25_dev;
+		netdev_put(ax25_dev->dev, &ax25_dev->dev_tracker);
+		ax25_dev = ax25_dev->next;
+		kfree(s);
+	}
+	ax25_dev_list = NULL;
+	spin_unlock_bh(&ax25_dev_lock);
+}
diff --git a/net/ax25/ax25_ds_in.c b/net/ax25/ax25_ds_in.c
new file mode 100644
index 000000000..c62f8fb06
--- /dev/null
+++ b/net/ax25/ax25_ds_in.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ */
+#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 <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+/*
+ *	State machine for state 1, Awaiting Connection State.
+ *	The handling of the timer(s) is in file ax25_ds_timer.c.
+ *	Handling of state 0 and connection release is in ax25.c.
+ */
+static int ax25_ds_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
+{
+	switch (frametype) {
+	case AX25_SABM:
+		ax25->modulus = AX25_MODULUS;
+		ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		break;
+
+	case AX25_SABME:
+		ax25->modulus = AX25_EMODULUS;
+		ax25->window  =  ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		break;
+
+	case AX25_DISC:
+		ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE);
+		break;
+
+	case AX25_UA:
+		ax25_calculate_rtt(ax25);
+		ax25_stop_t1timer(ax25);
+		ax25_start_t3timer(ax25);
+		ax25_start_idletimer(ax25);
+		ax25->vs      = 0;
+		ax25->va      = 0;
+		ax25->vr      = 0;
+		ax25->state   = AX25_STATE_3;
+		ax25->n2count = 0;
+		if (ax25->sk != NULL) {
+			bh_lock_sock(ax25->sk);
+			ax25->sk->sk_state = TCP_ESTABLISHED;
+			/*
+			 * For WAIT_SABM connections we will produce an accept
+			 * ready socket here
+			 */
+			if (!sock_flag(ax25->sk, SOCK_DEAD))
+				ax25->sk->sk_state_change(ax25->sk);
+			bh_unlock_sock(ax25->sk);
+		}
+		ax25_dama_on(ax25);
+
+		/* according to DK4EG's spec we are required to
+		 * send a RR RESPONSE FINAL NR=0.
+		 */
+
+		ax25_std_enquiry_response(ax25);
+		break;
+
+	case AX25_DM:
+		if (pf)
+			ax25_disconnect(ax25, ECONNREFUSED);
+		break;
+
+	default:
+		if (pf)
+			ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ *	State machine for state 2, Awaiting Release State.
+ *	The handling of the timer(s) is in file ax25_ds_timer.c
+ *	Handling of state 0 and connection release is in ax25.c.
+ */
+static int ax25_ds_state2_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
+{
+	switch (frametype) {
+	case AX25_SABM:
+	case AX25_SABME:
+		ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+		ax25_dama_off(ax25);
+		break;
+
+	case AX25_DISC:
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		ax25_dama_off(ax25);
+		ax25_disconnect(ax25, 0);
+		break;
+
+	case AX25_DM:
+	case AX25_UA:
+		if (pf) {
+			ax25_dama_off(ax25);
+			ax25_disconnect(ax25, 0);
+		}
+		break;
+
+	case AX25_I:
+	case AX25_REJ:
+	case AX25_RNR:
+	case AX25_RR:
+		if (pf) {
+			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+			ax25_dama_off(ax25);
+		}
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ *	State machine for state 3, Connected State.
+ *	The handling of the timer(s) is in file ax25_timer.c
+ *	Handling of state 0 and connection release is in ax25.c.
+ */
+static int ax25_ds_state3_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type)
+{
+	int queued = 0;
+
+	switch (frametype) {
+	case AX25_SABM:
+	case AX25_SABME:
+		if (frametype == AX25_SABM) {
+			ax25->modulus   = AX25_MODULUS;
+			ax25->window    = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+		} else {
+			ax25->modulus   = AX25_EMODULUS;
+			ax25->window    = ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
+		}
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		ax25_stop_t1timer(ax25);
+		ax25_start_t3timer(ax25);
+		ax25_start_idletimer(ax25);
+		ax25->condition = 0x00;
+		ax25->vs        = 0;
+		ax25->va        = 0;
+		ax25->vr        = 0;
+		ax25_requeue_frames(ax25);
+		ax25_dama_on(ax25);
+		break;
+
+	case AX25_DISC:
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		ax25_dama_off(ax25);
+		ax25_disconnect(ax25, 0);
+		break;
+
+	case AX25_DM:
+		ax25_dama_off(ax25);
+		ax25_disconnect(ax25, ECONNRESET);
+		break;
+
+	case AX25_RR:
+	case AX25_RNR:
+		if (frametype == AX25_RR)
+			ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
+		else
+			ax25->condition |= AX25_COND_PEER_RX_BUSY;
+
+		if (ax25_validate_nr(ax25, nr)) {
+			if (ax25_check_iframes_acked(ax25, nr))
+				ax25->n2count=0;
+			if (type == AX25_COMMAND && pf)
+				ax25_ds_enquiry_response(ax25);
+		} else {
+			ax25_ds_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+		}
+		break;
+
+	case AX25_REJ:
+		ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
+
+		if (ax25_validate_nr(ax25, nr)) {
+			if (ax25->va != nr)
+				ax25->n2count=0;
+
+			ax25_frames_acked(ax25, nr);
+			ax25_calculate_rtt(ax25);
+			ax25_stop_t1timer(ax25);
+			ax25_start_t3timer(ax25);
+			ax25_requeue_frames(ax25);
+
+			if (type == AX25_COMMAND && pf)
+				ax25_ds_enquiry_response(ax25);
+		} else {
+			ax25_ds_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+		}
+		break;
+
+	case AX25_I:
+		if (!ax25_validate_nr(ax25, nr)) {
+			ax25_ds_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+			break;
+		}
+		if (ax25->condition & AX25_COND_PEER_RX_BUSY) {
+			ax25_frames_acked(ax25, nr);
+			ax25->n2count = 0;
+		} else {
+			if (ax25_check_iframes_acked(ax25, nr))
+				ax25->n2count = 0;
+		}
+		if (ax25->condition & AX25_COND_OWN_RX_BUSY) {
+			if (pf) ax25_ds_enquiry_response(ax25);
+			break;
+		}
+		if (ns == ax25->vr) {
+			ax25->vr = (ax25->vr + 1) % ax25->modulus;
+			queued = ax25_rx_iframe(ax25, skb);
+			if (ax25->condition & AX25_COND_OWN_RX_BUSY)
+				ax25->vr = ns;	/* ax25->vr - 1 */
+			ax25->condition &= ~AX25_COND_REJECT;
+			if (pf) {
+				ax25_ds_enquiry_response(ax25);
+			} else {
+				if (!(ax25->condition & AX25_COND_ACK_PENDING)) {
+					ax25->condition |= AX25_COND_ACK_PENDING;
+					ax25_start_t2timer(ax25);
+				}
+			}
+		} else {
+			if (ax25->condition & AX25_COND_REJECT) {
+				if (pf) ax25_ds_enquiry_response(ax25);
+			} else {
+				ax25->condition |= AX25_COND_REJECT;
+				ax25_ds_enquiry_response(ax25);
+				ax25->condition &= ~AX25_COND_ACK_PENDING;
+			}
+		}
+		break;
+
+	case AX25_FRMR:
+	case AX25_ILLEGAL:
+		ax25_ds_establish_data_link(ax25);
+		ax25->state = AX25_STATE_1;
+		break;
+
+	default:
+		break;
+	}
+
+	return queued;
+}
+
+/*
+ *	Higher level upcall for a LAPB frame
+ */
+int ax25_ds_frame_in(ax25_cb *ax25, struct sk_buff *skb, int type)
+{
+	int queued = 0, frametype, ns, nr, pf;
+
+	frametype = ax25_decode(ax25, skb, &ns, &nr, &pf);
+
+	switch (ax25->state) {
+	case AX25_STATE_1:
+		queued = ax25_ds_state1_machine(ax25, skb, frametype, pf, type);
+		break;
+	case AX25_STATE_2:
+		queued = ax25_ds_state2_machine(ax25, skb, frametype, pf, type);
+		break;
+	case AX25_STATE_3:
+		queued = ax25_ds_state3_machine(ax25, skb, frametype, ns, nr, pf, type);
+		break;
+	}
+
+	return queued;
+}
diff --git a/net/ax25/ax25_ds_subr.c b/net/ax25/ax25_ds_subr.c
new file mode 100644
index 000000000..f00e27df3
--- /dev/null
+++ b/net/ax25/ax25_ds_subr.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ */
+#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/spinlock.h>
+#include <linux/net.h>
+#include <linux/gfp.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+void ax25_ds_nr_error_recovery(ax25_cb *ax25)
+{
+	ax25_ds_establish_data_link(ax25);
+}
+
+/*
+ *	dl1bke 960114: transmit I frames on DAMA poll
+ */
+void ax25_ds_enquiry_response(ax25_cb *ax25)
+{
+	ax25_cb *ax25o;
+
+	/* Please note that neither DK4EG's nor DG2FEF's
+	 * DAMA spec mention the following behaviour as seen
+	 * with TheFirmware:
+	 *
+	 * 	DB0ACH->DL1BKE <RR C P R0> [DAMA]
+	 *	DL1BKE->DB0ACH <I NR=0 NS=0>
+	 *	DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5>
+	 *	DL1BKE->DB0ACH <RR R F R0>
+	 *
+	 * The Flexnet DAMA Master implementation apparently
+	 * insists on the "proper" AX.25 behaviour:
+	 *
+	 * 	DB0ACH->DL1BKE <RR C P R0> [DAMA]
+	 *	DL1BKE->DB0ACH <RR R F R0>
+	 *	DL1BKE->DB0ACH <I NR=0 NS=0>
+	 *	DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5>
+	 *
+	 * Flexnet refuses to send us *any* I frame if we send
+	 * a REJ in case AX25_COND_REJECT is set. It is superfluous in
+	 * this mode anyway (a RR or RNR invokes the retransmission).
+	 * Is this a Flexnet bug?
+	 */
+
+	ax25_std_enquiry_response(ax25);
+
+	if (!(ax25->condition & AX25_COND_PEER_RX_BUSY)) {
+		ax25_requeue_frames(ax25);
+		ax25_kick(ax25);
+	}
+
+	if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2 || skb_peek(&ax25->ack_queue) != NULL)
+		ax25_ds_t1_timeout(ax25);
+	else
+		ax25->n2count = 0;
+
+	ax25_start_t3timer(ax25);
+	ax25_ds_set_timer(ax25->ax25_dev);
+
+	spin_lock(&ax25_list_lock);
+	ax25_for_each(ax25o, &ax25_list) {
+		if (ax25o == ax25)
+			continue;
+
+		if (ax25o->ax25_dev != ax25->ax25_dev)
+			continue;
+
+		if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2) {
+			ax25_ds_t1_timeout(ax25o);
+			continue;
+		}
+
+		if (!(ax25o->condition & AX25_COND_PEER_RX_BUSY) && ax25o->state == AX25_STATE_3) {
+			ax25_requeue_frames(ax25o);
+			ax25_kick(ax25o);
+		}
+
+		if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2 || skb_peek(&ax25o->ack_queue) != NULL)
+			ax25_ds_t1_timeout(ax25o);
+
+		/* do not start T3 for listening sockets (tnx DD8NE) */
+
+		if (ax25o->state != AX25_STATE_0)
+			ax25_start_t3timer(ax25o);
+	}
+	spin_unlock(&ax25_list_lock);
+}
+
+void ax25_ds_establish_data_link(ax25_cb *ax25)
+{
+	ax25->condition &= AX25_COND_DAMA_MODE;
+	ax25->n2count    = 0;
+	ax25_calculate_t1(ax25);
+	ax25_start_t1timer(ax25);
+	ax25_stop_t2timer(ax25);
+	ax25_start_t3timer(ax25);
+}
+
+/*
+ *	:::FIXME:::
+ *	This is a kludge. Not all drivers recognize kiss commands.
+ *	We need a driver level  request to switch duplex mode, that does
+ *	either SCC changing, PI config or KISS as required. Currently
+ *	this request isn't reliable.
+ */
+static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param)
+{
+	struct sk_buff *skb;
+	unsigned char *p;
+
+	if (ax25_dev->dev == NULL)
+		return;
+
+	if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL)
+		return;
+
+	skb_reset_network_header(skb);
+	p = skb_put(skb, 2);
+
+	*p++ = cmd;
+	*p++ = param;
+
+	skb->protocol = ax25_type_trans(skb, ax25_dev->dev);
+
+	dev_queue_xmit(skb);
+}
+
+/*
+ *	A nasty problem arises if we count the number of DAMA connections
+ *	wrong, especially when connections on the device already existed
+ *	and our network node (or the sysop) decides to turn on DAMA Master
+ *	mode. We thus flag the 'real' slave connections with
+ *	ax25->dama_slave=1 and look on every disconnect if still slave
+ *	connections exist.
+ */
+static int ax25_check_dama_slave(ax25_dev *ax25_dev)
+{
+	ax25_cb *ax25;
+	int res = 0;
+
+	spin_lock(&ax25_list_lock);
+	ax25_for_each(ax25, &ax25_list)
+		if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) {
+			res = 1;
+			break;
+		}
+	spin_unlock(&ax25_list_lock);
+
+	return res;
+}
+
+static void ax25_dev_dama_on(ax25_dev *ax25_dev)
+{
+	if (ax25_dev == NULL)
+		return;
+
+	if (ax25_dev->dama.slave == 0)
+		ax25_kiss_cmd(ax25_dev, 5, 1);
+
+	ax25_dev->dama.slave = 1;
+	ax25_ds_set_timer(ax25_dev);
+}
+
+void ax25_dev_dama_off(ax25_dev *ax25_dev)
+{
+	if (ax25_dev == NULL)
+		return;
+
+	if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev)) {
+		ax25_kiss_cmd(ax25_dev, 5, 0);
+		ax25_dev->dama.slave = 0;
+		ax25_ds_del_timer(ax25_dev);
+	}
+}
+
+void ax25_dama_on(ax25_cb *ax25)
+{
+	ax25_dev_dama_on(ax25->ax25_dev);
+	ax25->condition |= AX25_COND_DAMA_MODE;
+}
+
+void ax25_dama_off(ax25_cb *ax25)
+{
+	ax25->condition &= ~AX25_COND_DAMA_MODE;
+	ax25_dev_dama_off(ax25->ax25_dev);
+}
diff --git a/net/ax25/ax25_ds_timer.c b/net/ax25/ax25_ds_timer.c
new file mode 100644
index 000000000..c4f8adbf8
--- /dev/null
+++ b/net/ax25/ax25_ds_timer.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/spinlock.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <net/tcp_states.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+static void ax25_ds_timeout(struct timer_list *);
+
+/*
+ *	Add DAMA slave timeout timer to timer list.
+ *	Unlike the connection based timers the timeout function gets
+ *	triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT
+ *	(aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in
+ *	1/10th of a second.
+ */
+
+void ax25_ds_setup_timer(ax25_dev *ax25_dev)
+{
+	timer_setup(&ax25_dev->dama.slave_timer, ax25_ds_timeout, 0);
+}
+
+void ax25_ds_del_timer(ax25_dev *ax25_dev)
+{
+	if (ax25_dev)
+		del_timer(&ax25_dev->dama.slave_timer);
+}
+
+void ax25_ds_set_timer(ax25_dev *ax25_dev)
+{
+	if (ax25_dev == NULL)		/* paranoia */
+		return;
+
+	ax25_dev->dama.slave_timeout =
+		msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
+	mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
+}
+
+/*
+ *	DAMA Slave Timeout
+ *	Silently discard all (slave) connections in case our master forgot us...
+ */
+
+static void ax25_ds_timeout(struct timer_list *t)
+{
+	ax25_dev *ax25_dev = from_timer(ax25_dev, t, dama.slave_timer);
+	ax25_cb *ax25;
+
+	if (ax25_dev == NULL || !ax25_dev->dama.slave)
+		return;			/* Yikes! */
+
+	if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
+		ax25_ds_set_timer(ax25_dev);
+		return;
+	}
+
+	spin_lock(&ax25_list_lock);
+	ax25_for_each(ax25, &ax25_list) {
+		if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
+			continue;
+
+		ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+		ax25_disconnect(ax25, ETIMEDOUT);
+	}
+	spin_unlock(&ax25_list_lock);
+
+	ax25_dev_dama_off(ax25_dev);
+}
+
+void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
+{
+	struct sock *sk=ax25->sk;
+
+	if (sk)
+		bh_lock_sock(sk);
+
+	switch (ax25->state) {
+
+	case AX25_STATE_0:
+	case AX25_STATE_2:
+		/* Magic here: If we listen() and a new link dies before it
+		   is accepted() it isn't 'dead' so doesn't get removed. */
+		if (!sk || sock_flag(sk, SOCK_DESTROY) ||
+		    (sk->sk_state == TCP_LISTEN &&
+		     sock_flag(sk, SOCK_DEAD))) {
+			if (sk) {
+				sock_hold(sk);
+				ax25_destroy_socket(ax25);
+				bh_unlock_sock(sk);
+				/* Ungrab socket and destroy it */
+				sock_put(sk);
+			} else
+				ax25_destroy_socket(ax25);
+			return;
+		}
+		break;
+
+	case AX25_STATE_3:
+		/*
+		 * Check the state of the receive buffer.
+		 */
+		if (sk != NULL) {
+			if (atomic_read(&sk->sk_rmem_alloc) <
+			    (sk->sk_rcvbuf >> 1) &&
+			    (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
+				ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
+				ax25->condition &= ~AX25_COND_ACK_PENDING;
+				break;
+			}
+		}
+		break;
+	}
+
+	if (sk)
+		bh_unlock_sock(sk);
+
+	ax25_start_heartbeat(ax25);
+}
+
+/* dl1bke 960114: T3 works much like the IDLE timeout, but
+ *                gets reloaded with every frame for this
+ *		  connection.
+ */
+void ax25_ds_t3timer_expiry(ax25_cb *ax25)
+{
+	ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+	ax25_dama_off(ax25);
+	ax25_disconnect(ax25, ETIMEDOUT);
+}
+
+/* dl1bke 960228: close the connection when IDLE expires.
+ *		  unlike T3 this timer gets reloaded only on
+ *		  I frames.
+ */
+void ax25_ds_idletimer_expiry(ax25_cb *ax25)
+{
+	ax25_clear_queues(ax25);
+
+	ax25->n2count = 0;
+	ax25->state = AX25_STATE_2;
+
+	ax25_calculate_t1(ax25);
+	ax25_start_t1timer(ax25);
+	ax25_stop_t3timer(ax25);
+
+	if (ax25->sk != NULL) {
+		bh_lock_sock(ax25->sk);
+		ax25->sk->sk_state     = TCP_CLOSE;
+		ax25->sk->sk_err       = 0;
+		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
+		if (!sock_flag(ax25->sk, SOCK_DEAD)) {
+			ax25->sk->sk_state_change(ax25->sk);
+			sock_set_flag(ax25->sk, SOCK_DEAD);
+		}
+		bh_unlock_sock(ax25->sk);
+	}
+}
+
+/* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
+ *                within the poll of any connected channel. Remember
+ *                that we are not allowed to send anything unless we
+ *                get polled by the Master.
+ *
+ *                Thus we'll have to do parts of our T1 handling in
+ *                ax25_enquiry_response().
+ */
+void ax25_ds_t1_timeout(ax25_cb *ax25)
+{
+	switch (ax25->state) {
+	case AX25_STATE_1:
+		if (ax25->n2count == ax25->n2) {
+			if (ax25->modulus == AX25_MODULUS) {
+				ax25_disconnect(ax25, ETIMEDOUT);
+				return;
+			} else {
+				ax25->modulus = AX25_MODULUS;
+				ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+				ax25->n2count = 0;
+				ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
+			}
+		} else {
+			ax25->n2count++;
+			if (ax25->modulus == AX25_MODULUS)
+				ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
+			else
+				ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
+		}
+		break;
+
+	case AX25_STATE_2:
+		if (ax25->n2count == ax25->n2) {
+			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+			if (!sock_flag(ax25->sk, SOCK_DESTROY))
+				ax25_disconnect(ax25, ETIMEDOUT);
+			return;
+		} else {
+			ax25->n2count++;
+		}
+		break;
+
+	case AX25_STATE_3:
+		if (ax25->n2count == ax25->n2) {
+			ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
+			ax25_disconnect(ax25, ETIMEDOUT);
+			return;
+		} else {
+			ax25->n2count++;
+		}
+		break;
+	}
+
+	ax25_calculate_t1(ax25);
+	ax25_start_t1timer(ax25);
+}
diff --git a/net/ax25/ax25_iface.c b/net/ax25/ax25_iface.c
new file mode 100644
index 000000000..979bc4b82
--- /dev/null
+++ b/net/ax25/ax25_iface.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+static struct ax25_protocol *protocol_list;
+static DEFINE_RWLOCK(protocol_list_lock);
+
+static HLIST_HEAD(ax25_linkfail_list);
+static DEFINE_SPINLOCK(linkfail_lock);
+
+static struct listen_struct {
+	struct listen_struct *next;
+	ax25_address  callsign;
+	struct net_device *dev;
+} *listen_list = NULL;
+static DEFINE_SPINLOCK(listen_lock);
+
+/*
+ * Do not register the internal protocols AX25_P_TEXT, AX25_P_SEGMENT,
+ * AX25_P_IP or AX25_P_ARP ...
+ */
+void ax25_register_pid(struct ax25_protocol *ap)
+{
+	write_lock_bh(&protocol_list_lock);
+	ap->next = protocol_list;
+	protocol_list = ap;
+	write_unlock_bh(&protocol_list_lock);
+}
+
+EXPORT_SYMBOL_GPL(ax25_register_pid);
+
+void ax25_protocol_release(unsigned int pid)
+{
+	struct ax25_protocol *protocol;
+
+	write_lock_bh(&protocol_list_lock);
+	protocol = protocol_list;
+	if (protocol == NULL)
+		goto out;
+
+	if (protocol->pid == pid) {
+		protocol_list = protocol->next;
+		goto out;
+	}
+
+	while (protocol != NULL && protocol->next != NULL) {
+		if (protocol->next->pid == pid) {
+			protocol->next = protocol->next->next;
+			goto out;
+		}
+
+		protocol = protocol->next;
+	}
+out:
+	write_unlock_bh(&protocol_list_lock);
+}
+
+EXPORT_SYMBOL(ax25_protocol_release);
+
+void ax25_linkfail_register(struct ax25_linkfail *lf)
+{
+	spin_lock_bh(&linkfail_lock);
+	hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
+	spin_unlock_bh(&linkfail_lock);
+}
+
+EXPORT_SYMBOL(ax25_linkfail_register);
+
+void ax25_linkfail_release(struct ax25_linkfail *lf)
+{
+	spin_lock_bh(&linkfail_lock);
+	hlist_del_init(&lf->lf_node);
+	spin_unlock_bh(&linkfail_lock);
+}
+
+EXPORT_SYMBOL(ax25_linkfail_release);
+
+int ax25_listen_register(const ax25_address *callsign, struct net_device *dev)
+{
+	struct listen_struct *listen;
+
+	if (ax25_listen_mine(callsign, dev))
+		return 0;
+
+	if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
+		return -ENOMEM;
+
+	listen->callsign = *callsign;
+	listen->dev      = dev;
+
+	spin_lock_bh(&listen_lock);
+	listen->next = listen_list;
+	listen_list  = listen;
+	spin_unlock_bh(&listen_lock);
+
+	return 0;
+}
+
+EXPORT_SYMBOL(ax25_listen_register);
+
+void ax25_listen_release(const ax25_address *callsign, struct net_device *dev)
+{
+	struct listen_struct *s, *listen;
+
+	spin_lock_bh(&listen_lock);
+	listen = listen_list;
+	if (listen == NULL) {
+		spin_unlock_bh(&listen_lock);
+		return;
+	}
+
+	if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
+		listen_list = listen->next;
+		spin_unlock_bh(&listen_lock);
+		kfree(listen);
+		return;
+	}
+
+	while (listen != NULL && listen->next != NULL) {
+		if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
+			s = listen->next;
+			listen->next = listen->next->next;
+			spin_unlock_bh(&listen_lock);
+			kfree(s);
+			return;
+		}
+
+		listen = listen->next;
+	}
+	spin_unlock_bh(&listen_lock);
+}
+
+EXPORT_SYMBOL(ax25_listen_release);
+
+int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
+{
+	int (*res)(struct sk_buff *, ax25_cb *) = NULL;
+	struct ax25_protocol *protocol;
+
+	read_lock(&protocol_list_lock);
+	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
+		if (protocol->pid == pid) {
+			res = protocol->func;
+			break;
+		}
+	read_unlock(&protocol_list_lock);
+
+	return res;
+}
+
+int ax25_listen_mine(const ax25_address *callsign, struct net_device *dev)
+{
+	struct listen_struct *listen;
+
+	spin_lock_bh(&listen_lock);
+	for (listen = listen_list; listen != NULL; listen = listen->next)
+		if (ax25cmp(&listen->callsign, callsign) == 0 &&
+		    (listen->dev == dev || listen->dev == NULL)) {
+			spin_unlock_bh(&listen_lock);
+			return 1;
+	}
+	spin_unlock_bh(&listen_lock);
+
+	return 0;
+}
+
+void ax25_link_failed(ax25_cb *ax25, int reason)
+{
+	struct ax25_linkfail *lf;
+
+	spin_lock_bh(&linkfail_lock);
+	hlist_for_each_entry(lf, &ax25_linkfail_list, lf_node)
+		lf->func(ax25, reason);
+	spin_unlock_bh(&linkfail_lock);
+}
+
+int ax25_protocol_is_registered(unsigned int pid)
+{
+	struct ax25_protocol *protocol;
+	int res = 0;
+
+	read_lock_bh(&protocol_list_lock);
+	for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
+		if (protocol->pid == pid) {
+			res = 1;
+			break;
+		}
+	read_unlock_bh(&protocol_list_lock);
+
+	return res;
+}
diff --git a/net/ax25/ax25_in.c b/net/ax25/ax25_in.c
new file mode 100644
index 000000000..1cac25aca
--- /dev/null
+++ b/net/ax25/ax25_in.c
@@ -0,0 +1,451 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
+ */
+#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/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+/*
+ *	Given a fragment, queue it on the fragment queue and if the fragment
+ *	is complete, send it back to ax25_rx_iframe.
+ */
+static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb)
+{
+	struct sk_buff *skbn, *skbo;
+
+	if (ax25->fragno != 0) {
+		if (!(*skb->data & AX25_SEG_FIRST)) {
+			if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) {
+				/* Enqueue fragment */
+				ax25->fragno = *skb->data & AX25_SEG_REM;
+				skb_pull(skb, 1);	/* skip fragno */
+				ax25->fraglen += skb->len;
+				skb_queue_tail(&ax25->frag_queue, skb);
+
+				/* Last fragment received ? */
+				if (ax25->fragno == 0) {
+					skbn = alloc_skb(AX25_MAX_HEADER_LEN +
+							 ax25->fraglen,
+							 GFP_ATOMIC);
+					if (!skbn) {
+						skb_queue_purge(&ax25->frag_queue);
+						return 1;
+					}
+
+					skb_reserve(skbn, AX25_MAX_HEADER_LEN);
+
+					skbn->dev   = ax25->ax25_dev->dev;
+					skb_reset_network_header(skbn);
+					skb_reset_transport_header(skbn);
+
+					/* Copy data from the fragments */
+					while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) {
+						skb_copy_from_linear_data(skbo,
+							  skb_put(skbn, skbo->len),
+									  skbo->len);
+						kfree_skb(skbo);
+					}
+
+					ax25->fraglen = 0;
+
+					if (ax25_rx_iframe(ax25, skbn) == 0)
+						kfree_skb(skbn);
+				}
+
+				return 1;
+			}
+		}
+	} else {
+		/* First fragment received */
+		if (*skb->data & AX25_SEG_FIRST) {
+			skb_queue_purge(&ax25->frag_queue);
+			ax25->fragno = *skb->data & AX25_SEG_REM;
+			skb_pull(skb, 1);		/* skip fragno */
+			ax25->fraglen = skb->len;
+			skb_queue_tail(&ax25->frag_queue, skb);
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ *	This is where all valid I frames are sent to, to be dispatched to
+ *	whichever protocol requires them.
+ */
+int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb)
+{
+	int (*func)(struct sk_buff *, ax25_cb *);
+	unsigned char pid;
+	int queued = 0;
+
+	if (skb == NULL) return 0;
+
+	ax25_start_idletimer(ax25);
+
+	pid = *skb->data;
+
+	if (pid == AX25_P_IP) {
+		/* working around a TCP bug to keep additional listeners
+		 * happy. TCP re-uses the buffer and destroys the original
+		 * content.
+		 */
+		struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC);
+		if (skbn != NULL) {
+			kfree_skb(skb);
+			skb = skbn;
+		}
+
+		skb_pull(skb, 1);	/* Remove PID */
+		skb->mac_header = skb->network_header;
+		skb_reset_network_header(skb);
+		skb->dev      = ax25->ax25_dev->dev;
+		skb->pkt_type = PACKET_HOST;
+		skb->protocol = htons(ETH_P_IP);
+		netif_rx(skb);
+		return 1;
+	}
+	if (pid == AX25_P_SEGMENT) {
+		skb_pull(skb, 1);	/* Remove PID */
+		return ax25_rx_fragment(ax25, skb);
+	}
+
+	if ((func = ax25_protocol_function(pid)) != NULL) {
+		skb_pull(skb, 1);	/* Remove PID */
+		return (*func)(skb, ax25);
+	}
+
+	if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) {
+		if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) ||
+		    ax25->pidincl) {
+			if (sock_queue_rcv_skb(ax25->sk, skb) == 0)
+				queued = 1;
+			else
+				ax25->condition |= AX25_COND_OWN_RX_BUSY;
+		}
+	}
+
+	return queued;
+}
+
+/*
+ *	Higher level upcall for a LAPB frame
+ */
+static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama)
+{
+	int queued = 0;
+
+	if (ax25->state == AX25_STATE_0)
+		return 0;
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		queued = ax25_std_frame_in(ax25, skb, type);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		if (dama || ax25->ax25_dev->dama.slave)
+			queued = ax25_ds_frame_in(ax25, skb, type);
+		else
+			queued = ax25_std_frame_in(ax25, skb, type);
+		break;
+#endif
+	}
+
+	return queued;
+}
+
+static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
+		    const ax25_address *dev_addr, struct packet_type *ptype)
+{
+	ax25_address src, dest, *next_digi = NULL;
+	int type = 0, mine = 0, dama;
+	struct sock *make, *sk;
+	ax25_digi dp, reverse_dp;
+	ax25_cb *ax25;
+	ax25_dev *ax25_dev;
+
+	/*
+	 *	Process the AX.25/LAPB frame.
+	 */
+
+	skb_reset_transport_header(skb);
+
+	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
+		goto free;
+
+	/*
+	 *	Parse the address header.
+	 */
+
+	if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL)
+		goto free;
+
+	/*
+	 *	Ours perhaps ?
+	 */
+	if (dp.lastrepeat + 1 < dp.ndigi)		/* Not yet digipeated completely */
+		next_digi = &dp.calls[dp.lastrepeat + 1];
+
+	/*
+	 *	Pull of the AX.25 headers leaving the CTRL/PID bytes
+	 */
+	skb_pull(skb, ax25_addr_size(&dp));
+
+	/* For our port addresses ? */
+	if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi)
+		mine = 1;
+
+	/* Also match on any registered callsign from L3/4 */
+	if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi)
+		mine = 1;
+
+	/* UI frame - bypass LAPB processing */
+	if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) {
+		skb_set_transport_header(skb, 2); /* skip control and pid */
+
+		ax25_send_to_raw(&dest, skb, skb->data[1]);
+
+		if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0)
+			goto free;
+
+		/* Now we are pointing at the pid byte */
+		switch (skb->data[1]) {
+		case AX25_P_IP:
+			skb_pull(skb,2);		/* drop PID/CTRL */
+			skb_reset_transport_header(skb);
+			skb_reset_network_header(skb);
+			skb->dev      = dev;
+			skb->pkt_type = PACKET_HOST;
+			skb->protocol = htons(ETH_P_IP);
+			netif_rx(skb);
+			break;
+
+		case AX25_P_ARP:
+			skb_pull(skb,2);
+			skb_reset_transport_header(skb);
+			skb_reset_network_header(skb);
+			skb->dev      = dev;
+			skb->pkt_type = PACKET_HOST;
+			skb->protocol = htons(ETH_P_ARP);
+			netif_rx(skb);
+			break;
+		case AX25_P_TEXT:
+			/* Now find a suitable dgram socket */
+			sk = ax25_get_socket(&dest, &src, SOCK_DGRAM);
+			if (sk != NULL) {
+				bh_lock_sock(sk);
+				if (atomic_read(&sk->sk_rmem_alloc) >=
+				    sk->sk_rcvbuf) {
+					kfree_skb(skb);
+				} else {
+					/*
+					 *	Remove the control and PID.
+					 */
+					skb_pull(skb, 2);
+					if (sock_queue_rcv_skb(sk, skb) != 0)
+						kfree_skb(skb);
+				}
+				bh_unlock_sock(sk);
+				sock_put(sk);
+			} else {
+				kfree_skb(skb);
+			}
+			break;
+
+		default:
+			kfree_skb(skb);	/* Will scan SOCK_AX25 RAW sockets */
+			break;
+		}
+
+		return 0;
+	}
+
+	/*
+	 *	Is connected mode supported on this device ?
+	 *	If not, should we DM the incoming frame (except DMs) or
+	 *	silently ignore them. For now we stay quiet.
+	 */
+	if (ax25_dev->values[AX25_VALUES_CONMODE] == 0)
+		goto free;
+
+	/* LAPB */
+
+	/* AX.25 state 1-4 */
+
+	ax25_digi_invert(&dp, &reverse_dp);
+
+	if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) {
+		/*
+		 *	Process the frame. If it is queued up internally it
+		 *	returns one otherwise we free it immediately. This
+		 *	routine itself wakes the user context layers so we do
+		 *	no further work
+		 */
+		if (ax25_process_rx_frame(ax25, skb, type, dama) == 0)
+			kfree_skb(skb);
+
+		ax25_cb_put(ax25);
+		return 0;
+	}
+
+	/* AX.25 state 0 (disconnected) */
+
+	/* a) received not a SABM(E) */
+
+	if ((*skb->data & ~AX25_PF) != AX25_SABM &&
+	    (*skb->data & ~AX25_PF) != AX25_SABME) {
+		/*
+		 *	Never reply to a DM. Also ignore any connects for
+		 *	addresses that are not our interfaces and not a socket.
+		 */
+		if ((*skb->data & ~AX25_PF) != AX25_DM && mine)
+			ax25_return_dm(dev, &src, &dest, &dp);
+
+		goto free;
+	}
+
+	/* b) received SABM(E) */
+
+	if (dp.lastrepeat + 1 == dp.ndigi)
+		sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET);
+	else
+		sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET);
+
+	if (sk != NULL) {
+		bh_lock_sock(sk);
+		if (sk_acceptq_is_full(sk) ||
+		    (make = ax25_make_new(sk, ax25_dev)) == NULL) {
+			if (mine)
+				ax25_return_dm(dev, &src, &dest, &dp);
+			kfree_skb(skb);
+			bh_unlock_sock(sk);
+			sock_put(sk);
+
+			return 0;
+		}
+
+		ax25 = sk_to_ax25(make);
+		skb_set_owner_r(skb, make);
+		skb_queue_head(&sk->sk_receive_queue, skb);
+
+		make->sk_state = TCP_ESTABLISHED;
+
+		sk_acceptq_added(sk);
+		bh_unlock_sock(sk);
+	} else {
+		if (!mine)
+			goto free;
+
+		if ((ax25 = ax25_create_cb()) == NULL) {
+			ax25_return_dm(dev, &src, &dest, &dp);
+			goto free;
+		}
+
+		ax25_fillin_cb(ax25, ax25_dev);
+	}
+
+	ax25->source_addr = dest;
+	ax25->dest_addr   = src;
+
+	/*
+	 *	Sort out any digipeated paths.
+	 */
+	if (dp.ndigi && !ax25->digipeat &&
+	    (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
+		kfree_skb(skb);
+		ax25_destroy_socket(ax25);
+		if (sk)
+			sock_put(sk);
+		return 0;
+	}
+
+	if (dp.ndigi == 0) {
+		kfree(ax25->digipeat);
+		ax25->digipeat = NULL;
+	} else {
+		/* Reverse the source SABM's path */
+		memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi));
+	}
+
+	if ((*skb->data & ~AX25_PF) == AX25_SABME) {
+		ax25->modulus = AX25_EMODULUS;
+		ax25->window  = ax25_dev->values[AX25_VALUES_EWINDOW];
+	} else {
+		ax25->modulus = AX25_MODULUS;
+		ax25->window  = ax25_dev->values[AX25_VALUES_WINDOW];
+	}
+
+	ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE);
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
+		ax25_dama_on(ax25);
+#endif
+
+	ax25->state = AX25_STATE_3;
+
+	ax25_cb_add(ax25);
+
+	ax25_start_heartbeat(ax25);
+	ax25_start_t3timer(ax25);
+	ax25_start_idletimer(ax25);
+
+	if (sk) {
+		if (!sock_flag(sk, SOCK_DEAD))
+			sk->sk_data_ready(sk);
+		sock_put(sk);
+	} else {
+free:
+		kfree_skb(skb);
+	}
+	return 0;
+}
+
+/*
+ *	Receive an AX.25 frame via a SLIP interface.
+ */
+int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev,
+		  struct packet_type *ptype, struct net_device *orig_dev)
+{
+	skb_orphan(skb);
+
+	if (!net_eq(dev_net(dev), &init_net)) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	if ((*skb->data & 0x0F) != 0) {
+		kfree_skb(skb);	/* Not a KISS data frame */
+		return 0;
+	}
+
+	skb_pull(skb, AX25_KISS_HEADER_LEN);	/* Remove the KISS byte */
+
+	return ax25_rcv(skb, dev, (const ax25_address *)dev->dev_addr, ptype);
+}
diff --git a/net/ax25/ax25_ip.c b/net/ax25/ax25_ip.c
new file mode 100644
index 000000000..36249776c
--- /dev/null
+++ b/net/ax25/ax25_ip.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/termios.h>	/* For TIOCINQ/OUTQ */
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/sysctl.h>
+#include <net/ip.h>
+#include <net/arp.h>
+
+/*
+ *	IP over AX.25 encapsulation.
+ */
+
+/*
+ *	Shove an AX.25 UI header on an IP packet and handle ARP
+ */
+
+#ifdef CONFIG_INET
+
+static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
+			    unsigned short type, const void *daddr,
+			    const void *saddr, unsigned int len)
+{
+	unsigned char *buff;
+
+	/* they sometimes come back to us... */
+	if (type == ETH_P_AX25)
+		return 0;
+
+	/* header is an AX.25 UI frame from us to them */
+	buff = skb_push(skb, AX25_HEADER_LEN);
+	*buff++ = 0x00;	/* KISS DATA */
+
+	if (daddr != NULL)
+		memcpy(buff, daddr, dev->addr_len);	/* Address specified */
+
+	buff[6] &= ~AX25_CBIT;
+	buff[6] &= ~AX25_EBIT;
+	buff[6] |= AX25_SSSID_SPARE;
+	buff    += AX25_ADDR_LEN;
+
+	if (saddr != NULL)
+		memcpy(buff, saddr, dev->addr_len);
+	else
+		memcpy(buff, dev->dev_addr, dev->addr_len);
+
+	buff[6] &= ~AX25_CBIT;
+	buff[6] |= AX25_EBIT;
+	buff[6] |= AX25_SSSID_SPARE;
+	buff    += AX25_ADDR_LEN;
+
+	*buff++  = AX25_UI;	/* UI */
+
+	/* Append a suitable AX.25 PID */
+	switch (type) {
+	case ETH_P_IP:
+		*buff++ = AX25_P_IP;
+		break;
+	case ETH_P_ARP:
+		*buff++ = AX25_P_ARP;
+		break;
+	default:
+		printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type);
+		*buff++ = 0;
+		break;
+	}
+
+	if (daddr != NULL)
+		return AX25_HEADER_LEN;
+
+	return -AX25_HEADER_LEN;	/* Unfinished header */
+}
+
+netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
+{
+	struct sk_buff *ourskb;
+	unsigned char *bp  = skb->data;
+	ax25_route *route;
+	struct net_device *dev = NULL;
+	ax25_address *src, *dst;
+	ax25_digi *digipeat = NULL;
+	ax25_dev *ax25_dev;
+	ax25_cb *ax25;
+	char ip_mode = ' ';
+
+	dst = (ax25_address *)(bp + 1);
+	src = (ax25_address *)(bp + 8);
+
+	ax25_route_lock_use();
+	route = ax25_get_route(dst, NULL);
+	if (route) {
+		digipeat = route->digipeat;
+		dev = route->dev;
+		ip_mode = route->ip_mode;
+	}
+
+	if (dev == NULL)
+		dev = skb->dev;
+
+	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
+		kfree_skb(skb);
+		goto put;
+	}
+
+	if (bp[16] == AX25_P_IP) {
+		if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
+			/*
+			 *	We copy the buffer and release the original thereby
+			 *	keeping it straight
+			 *
+			 *	Note: we report 1 back so the caller will
+			 *	not feed the frame direct to the physical device
+			 *	We don't want that to happen. (It won't be upset
+			 *	as we have pulled the frame from the queue by
+			 *	freeing it).
+			 *
+			 *	NB: TCP modifies buffers that are still
+			 *	on a device queue, thus we use skb_copy()
+			 *      instead of using skb_clone() unless this
+			 *	gets fixed.
+			 */
+
+			ax25_address src_c;
+			ax25_address dst_c;
+
+			if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
+				kfree_skb(skb);
+				goto put;
+			}
+
+			if (skb->sk != NULL)
+				skb_set_owner_w(ourskb, skb->sk);
+
+			kfree_skb(skb);
+			/* dl9sau: bugfix
+			 * after kfree_skb(), dst and src which were pointer
+			 * to bp which is part of skb->data would not be valid
+			 * anymore hope that after skb_pull(ourskb, ..) our
+			 * dsc_c and src_c will not become invalid
+			 */
+			bp  = ourskb->data;
+			dst_c = *(ax25_address *)(bp + 1);
+			src_c = *(ax25_address *)(bp + 8);
+
+			skb_pull(ourskb, AX25_HEADER_LEN - 1);	/* Keep PID */
+			skb_reset_network_header(ourskb);
+
+			ax25=ax25_send_frame(
+			    ourskb,
+			    ax25_dev->values[AX25_VALUES_PACLEN],
+			    &src_c,
+			    &dst_c, digipeat, dev);
+			if (ax25) {
+				ax25_cb_put(ax25);
+			}
+			goto put;
+		}
+	}
+
+	bp[7]  &= ~AX25_CBIT;
+	bp[7]  &= ~AX25_EBIT;
+	bp[7]  |= AX25_SSSID_SPARE;
+
+	bp[14] &= ~AX25_CBIT;
+	bp[14] |= AX25_EBIT;
+	bp[14] |= AX25_SSSID_SPARE;
+
+	skb_pull(skb, AX25_KISS_HEADER_LEN);
+
+	if (digipeat != NULL) {
+		if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL)
+			goto put;
+
+		skb = ourskb;
+	}
+
+	ax25_queue_xmit(skb, dev);
+
+put:
+
+	ax25_route_lock_unuse();
+	return NETDEV_TX_OK;
+}
+
+#else	/* INET */
+
+static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
+			    unsigned short type, const void *daddr,
+			    const void *saddr, unsigned int len)
+{
+	return -AX25_HEADER_LEN;
+}
+
+netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
+{
+	kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+#endif
+
+static bool ax25_validate_header(const char *header, unsigned int len)
+{
+	ax25_digi digi;
+
+	if (!len)
+		return false;
+
+	if (header[0])
+		return true;
+
+	return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL,
+			       NULL);
+}
+
+const struct header_ops ax25_header_ops = {
+	.create = ax25_hard_header,
+	.validate = ax25_validate_header,
+};
+
+EXPORT_SYMBOL(ax25_header_ops);
+EXPORT_SYMBOL(ax25_ip_xmit);
diff --git a/net/ax25/ax25_out.c b/net/ax25/ax25_out.c
new file mode 100644
index 000000000..3db76d247
--- /dev/null
+++ b/net/ax25/ax25_out.c
@@ -0,0 +1,386 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/spinlock.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+static DEFINE_SPINLOCK(ax25_frag_lock);
+
+ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, const ax25_address *src, ax25_address *dest, ax25_digi *digi, struct net_device *dev)
+{
+	ax25_dev *ax25_dev;
+	ax25_cb *ax25;
+
+	/*
+	 * Take the default packet length for the device if zero is
+	 * specified.
+	 */
+	if (paclen == 0) {
+		if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
+			return NULL;
+
+		paclen = ax25_dev->values[AX25_VALUES_PACLEN];
+	}
+
+	/*
+	 * Look for an existing connection.
+	 */
+	if ((ax25 = ax25_find_cb(src, dest, digi, dev)) != NULL) {
+		ax25_output(ax25, paclen, skb);
+		return ax25;		/* It already existed */
+	}
+
+	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
+		return NULL;
+
+	if ((ax25 = ax25_create_cb()) == NULL)
+		return NULL;
+
+	ax25_fillin_cb(ax25, ax25_dev);
+
+	ax25->source_addr = *src;
+	ax25->dest_addr   = *dest;
+
+	if (digi != NULL) {
+		ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC);
+		if (ax25->digipeat == NULL) {
+			ax25_cb_put(ax25);
+			return NULL;
+		}
+	}
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_std_establish_data_link(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		if (ax25_dev->dama.slave)
+			ax25_ds_establish_data_link(ax25);
+		else
+			ax25_std_establish_data_link(ax25);
+		break;
+#endif
+	}
+
+	/*
+	 * There is one ref for the state machine; a caller needs
+	 * one more to put it back, just like with the existing one.
+	 */
+	ax25_cb_hold(ax25);
+
+	ax25_cb_add(ax25);
+
+	ax25->state = AX25_STATE_1;
+
+	ax25_start_heartbeat(ax25);
+
+	ax25_output(ax25, paclen, skb);
+
+	return ax25;			/* We had to create it */
+}
+
+EXPORT_SYMBOL(ax25_send_frame);
+
+/*
+ *	All outgoing AX.25 I frames pass via this routine. Therefore this is
+ *	where the fragmentation of frames takes place. If fragment is set to
+ *	zero then we are not allowed to do fragmentation, even if the frame
+ *	is too large.
+ */
+void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb)
+{
+	struct sk_buff *skbn;
+	unsigned char *p;
+	int frontlen, len, fragno, ka9qfrag, first = 1;
+
+	if (paclen < 16) {
+		WARN_ON_ONCE(1);
+		kfree_skb(skb);
+		return;
+	}
+
+	if ((skb->len - 1) > paclen) {
+		if (*skb->data == AX25_P_TEXT) {
+			skb_pull(skb, 1); /* skip PID */
+			ka9qfrag = 0;
+		} else {
+			paclen -= 2;	/* Allow for fragment control info */
+			ka9qfrag = 1;
+		}
+
+		fragno = skb->len / paclen;
+		if (skb->len % paclen == 0) fragno--;
+
+		frontlen = skb_headroom(skb);	/* Address space + CTRL */
+
+		while (skb->len > 0) {
+			spin_lock_bh(&ax25_frag_lock);
+			if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) {
+				spin_unlock_bh(&ax25_frag_lock);
+				printk(KERN_CRIT "AX.25: ax25_output - out of memory\n");
+				return;
+			}
+
+			if (skb->sk != NULL)
+				skb_set_owner_w(skbn, skb->sk);
+
+			spin_unlock_bh(&ax25_frag_lock);
+
+			len = (paclen > skb->len) ? skb->len : paclen;
+
+			if (ka9qfrag == 1) {
+				skb_reserve(skbn, frontlen + 2);
+				skb_set_network_header(skbn,
+						      skb_network_offset(skb));
+				skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
+				p = skb_push(skbn, 2);
+
+				*p++ = AX25_P_SEGMENT;
+
+				*p = fragno--;
+				if (first) {
+					*p |= AX25_SEG_FIRST;
+					first = 0;
+				}
+			} else {
+				skb_reserve(skbn, frontlen + 1);
+				skb_set_network_header(skbn,
+						      skb_network_offset(skb));
+				skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
+				p = skb_push(skbn, 1);
+				*p = AX25_P_TEXT;
+			}
+
+			skb_pull(skb, len);
+			skb_queue_tail(&ax25->write_queue, skbn); /* Throw it on the queue */
+		}
+
+		kfree_skb(skb);
+	} else {
+		skb_queue_tail(&ax25->write_queue, skb);	  /* Throw it on the queue */
+	}
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_kick(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	/*
+	 * A DAMA slave is _required_ to work as normal AX.25L2V2
+	 * if no DAMA master is available.
+	 */
+	case AX25_PROTO_DAMA_SLAVE:
+		if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25);
+		break;
+#endif
+	}
+}
+
+/*
+ *  This procedure is passed a buffer descriptor for an iframe. It builds
+ *  the rest of the control part of the frame and then writes it out.
+ */
+static void ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit)
+{
+	unsigned char *frame;
+
+	if (skb == NULL)
+		return;
+
+	skb_reset_network_header(skb);
+
+	if (ax25->modulus == AX25_MODULUS) {
+		frame = skb_push(skb, 1);
+
+		*frame = AX25_I;
+		*frame |= (poll_bit) ? AX25_PF : 0;
+		*frame |= (ax25->vr << 5);
+		*frame |= (ax25->vs << 1);
+	} else {
+		frame = skb_push(skb, 2);
+
+		frame[0] = AX25_I;
+		frame[0] |= (ax25->vs << 1);
+		frame[1] = (poll_bit) ? AX25_EPF : 0;
+		frame[1] |= (ax25->vr << 1);
+	}
+
+	ax25_start_idletimer(ax25);
+
+	ax25_transmit_buffer(ax25, skb, AX25_COMMAND);
+}
+
+void ax25_kick(ax25_cb *ax25)
+{
+	struct sk_buff *skb, *skbn;
+	int last = 1;
+	unsigned short start, end, next;
+
+	if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4)
+		return;
+
+	if (ax25->condition & AX25_COND_PEER_RX_BUSY)
+		return;
+
+	if (skb_peek(&ax25->write_queue) == NULL)
+		return;
+
+	start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs;
+	end   = (ax25->va + ax25->window) % ax25->modulus;
+
+	if (start == end)
+		return;
+
+	/*
+	 * Transmit data until either we're out of data to send or
+	 * the window is full. Send a poll on the final I frame if
+	 * the window is filled.
+	 */
+
+	/*
+	 * Dequeue the frame and copy it.
+	 * Check for race with ax25_clear_queues().
+	 */
+	skb  = skb_dequeue(&ax25->write_queue);
+	if (!skb)
+		return;
+
+	ax25->vs = start;
+
+	do {
+		if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
+			skb_queue_head(&ax25->write_queue, skb);
+			break;
+		}
+
+		if (skb->sk != NULL)
+			skb_set_owner_w(skbn, skb->sk);
+
+		next = (ax25->vs + 1) % ax25->modulus;
+		last = (next == end);
+
+		/*
+		 * Transmit the frame copy.
+		 * bke 960114: do not set the Poll bit on the last frame
+		 * in DAMA mode.
+		 */
+		switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+		case AX25_PROTO_STD_SIMPLEX:
+		case AX25_PROTO_STD_DUPLEX:
+			ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF);
+			break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+		case AX25_PROTO_DAMA_SLAVE:
+			ax25_send_iframe(ax25, skbn, AX25_POLLOFF);
+			break;
+#endif
+		}
+
+		ax25->vs = next;
+
+		/*
+		 * Requeue the original data frame.
+		 */
+		skb_queue_tail(&ax25->ack_queue, skb);
+
+	} while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL);
+
+	ax25->condition &= ~AX25_COND_ACK_PENDING;
+
+	if (!ax25_t1timer_running(ax25)) {
+		ax25_stop_t3timer(ax25);
+		ax25_calculate_t1(ax25);
+		ax25_start_t1timer(ax25);
+	}
+}
+
+void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type)
+{
+	unsigned char *ptr;
+	int headroom;
+
+	if (ax25->ax25_dev == NULL) {
+		ax25_disconnect(ax25, ENETUNREACH);
+		return;
+	}
+
+	headroom = ax25_addr_size(ax25->digipeat);
+
+	if (unlikely(skb_headroom(skb) < headroom)) {
+		skb = skb_expand_head(skb, headroom);
+		if (!skb) {
+			printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n");
+			return;
+		}
+	}
+
+	ptr = skb_push(skb, headroom);
+
+	ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus);
+
+	ax25_queue_xmit(skb, ax25->ax25_dev->dev);
+}
+
+/*
+ *	A small shim to dev_queue_xmit to add the KISS control byte, and do
+ *	any packet forwarding in operation.
+ */
+void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	unsigned char *ptr;
+
+	skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev));
+
+	ptr  = skb_push(skb, 1);
+	*ptr = 0x00;			/* KISS */
+
+	dev_queue_xmit(skb);
+}
+
+int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr)
+{
+	if (ax25->vs == nr) {
+		ax25_frames_acked(ax25, nr);
+		ax25_calculate_rtt(ax25);
+		ax25_stop_t1timer(ax25);
+		ax25_start_t3timer(ax25);
+		return 1;
+	} else {
+		if (ax25->va != nr) {
+			ax25_frames_acked(ax25, nr);
+			ax25_calculate_t1(ax25);
+			ax25_start_t1timer(ax25);
+			return 1;
+		}
+	}
+	return 0;
+}
diff --git a/net/ax25/ax25_route.c b/net/ax25/ax25_route.c
new file mode 100644
index 000000000..b7c4d656a
--- /dev/null
+++ b/net/ax25/ax25_route.c
@@ -0,0 +1,488 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Steven Whitehouse GW7RRM (stevew@acm.org)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
+ * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
+ */
+
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/timer.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/export.h>
+
+static ax25_route *ax25_route_list;
+DEFINE_RWLOCK(ax25_route_lock);
+
+void ax25_rt_device_down(struct net_device *dev)
+{
+	ax25_route *s, *t, *ax25_rt;
+
+	write_lock_bh(&ax25_route_lock);
+	ax25_rt = ax25_route_list;
+	while (ax25_rt != NULL) {
+		s       = ax25_rt;
+		ax25_rt = ax25_rt->next;
+
+		if (s->dev == dev) {
+			if (ax25_route_list == s) {
+				ax25_route_list = s->next;
+				kfree(s->digipeat);
+				kfree(s);
+			} else {
+				for (t = ax25_route_list; t != NULL; t = t->next) {
+					if (t->next == s) {
+						t->next = s->next;
+						kfree(s->digipeat);
+						kfree(s);
+						break;
+					}
+				}
+			}
+		}
+	}
+	write_unlock_bh(&ax25_route_lock);
+}
+
+static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
+{
+	ax25_route *ax25_rt;
+	ax25_dev *ax25_dev;
+	int i;
+
+	if (route->digi_count > AX25_MAX_DIGIS)
+		return -EINVAL;
+
+	ax25_dev = ax25_addr_ax25dev(&route->port_addr);
+	if (!ax25_dev)
+		return -EINVAL;
+
+	write_lock_bh(&ax25_route_lock);
+
+	ax25_rt = ax25_route_list;
+	while (ax25_rt != NULL) {
+		if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
+			    ax25_rt->dev == ax25_dev->dev) {
+			kfree(ax25_rt->digipeat);
+			ax25_rt->digipeat = NULL;
+			if (route->digi_count != 0) {
+				if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
+					write_unlock_bh(&ax25_route_lock);
+					ax25_dev_put(ax25_dev);
+					return -ENOMEM;
+				}
+				ax25_rt->digipeat->lastrepeat = -1;
+				ax25_rt->digipeat->ndigi      = route->digi_count;
+				for (i = 0; i < route->digi_count; i++) {
+					ax25_rt->digipeat->repeated[i] = 0;
+					ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
+				}
+			}
+			write_unlock_bh(&ax25_route_lock);
+			ax25_dev_put(ax25_dev);
+			return 0;
+		}
+		ax25_rt = ax25_rt->next;
+	}
+
+	if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
+		write_unlock_bh(&ax25_route_lock);
+		ax25_dev_put(ax25_dev);
+		return -ENOMEM;
+	}
+
+	ax25_rt->callsign     = route->dest_addr;
+	ax25_rt->dev          = ax25_dev->dev;
+	ax25_rt->digipeat     = NULL;
+	ax25_rt->ip_mode      = ' ';
+	if (route->digi_count != 0) {
+		if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
+			write_unlock_bh(&ax25_route_lock);
+			kfree(ax25_rt);
+			ax25_dev_put(ax25_dev);
+			return -ENOMEM;
+		}
+		ax25_rt->digipeat->lastrepeat = -1;
+		ax25_rt->digipeat->ndigi      = route->digi_count;
+		for (i = 0; i < route->digi_count; i++) {
+			ax25_rt->digipeat->repeated[i] = 0;
+			ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
+		}
+	}
+	ax25_rt->next   = ax25_route_list;
+	ax25_route_list = ax25_rt;
+	write_unlock_bh(&ax25_route_lock);
+	ax25_dev_put(ax25_dev);
+
+	return 0;
+}
+
+void __ax25_put_route(ax25_route *ax25_rt)
+{
+	kfree(ax25_rt->digipeat);
+	kfree(ax25_rt);
+}
+
+static int ax25_rt_del(struct ax25_routes_struct *route)
+{
+	ax25_route *s, *t, *ax25_rt;
+	ax25_dev *ax25_dev;
+
+	if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
+		return -EINVAL;
+
+	write_lock_bh(&ax25_route_lock);
+
+	ax25_rt = ax25_route_list;
+	while (ax25_rt != NULL) {
+		s       = ax25_rt;
+		ax25_rt = ax25_rt->next;
+		if (s->dev == ax25_dev->dev &&
+		    ax25cmp(&route->dest_addr, &s->callsign) == 0) {
+			if (ax25_route_list == s) {
+				ax25_route_list = s->next;
+				__ax25_put_route(s);
+			} else {
+				for (t = ax25_route_list; t != NULL; t = t->next) {
+					if (t->next == s) {
+						t->next = s->next;
+						__ax25_put_route(s);
+						break;
+					}
+				}
+			}
+		}
+	}
+	write_unlock_bh(&ax25_route_lock);
+	ax25_dev_put(ax25_dev);
+
+	return 0;
+}
+
+static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
+{
+	ax25_route *ax25_rt;
+	ax25_dev *ax25_dev;
+	int err = 0;
+
+	if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
+		return -EINVAL;
+
+	write_lock_bh(&ax25_route_lock);
+
+	ax25_rt = ax25_route_list;
+	while (ax25_rt != NULL) {
+		if (ax25_rt->dev == ax25_dev->dev &&
+		    ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
+			switch (rt_option->cmd) {
+			case AX25_SET_RT_IPMODE:
+				switch (rt_option->arg) {
+				case ' ':
+				case 'D':
+				case 'V':
+					ax25_rt->ip_mode = rt_option->arg;
+					break;
+				default:
+					err = -EINVAL;
+					goto out;
+				}
+				break;
+			default:
+				err = -EINVAL;
+				goto out;
+			}
+		}
+		ax25_rt = ax25_rt->next;
+	}
+
+out:
+	write_unlock_bh(&ax25_route_lock);
+	ax25_dev_put(ax25_dev);
+	return err;
+}
+
+int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
+{
+	struct ax25_route_opt_struct rt_option;
+	struct ax25_routes_struct route;
+
+	switch (cmd) {
+	case SIOCADDRT:
+		if (copy_from_user(&route, arg, sizeof(route)))
+			return -EFAULT;
+		return ax25_rt_add(&route);
+
+	case SIOCDELRT:
+		if (copy_from_user(&route, arg, sizeof(route)))
+			return -EFAULT;
+		return ax25_rt_del(&route);
+
+	case SIOCAX25OPTRT:
+		if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
+			return -EFAULT;
+		return ax25_rt_opt(&rt_option);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+#ifdef CONFIG_PROC_FS
+
+static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(ax25_route_lock)
+{
+	struct ax25_route *ax25_rt;
+	int i = 1;
+
+	read_lock(&ax25_route_lock);
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
+		if (i == *pos)
+			return ax25_rt;
+		++i;
+	}
+
+	return NULL;
+}
+
+static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	++*pos;
+	return (v == SEQ_START_TOKEN) ? ax25_route_list :
+		((struct ax25_route *) v)->next;
+}
+
+static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
+	__releases(ax25_route_lock)
+{
+	read_unlock(&ax25_route_lock);
+}
+
+static int ax25_rt_seq_show(struct seq_file *seq, void *v)
+{
+	char buf[11];
+
+	if (v == SEQ_START_TOKEN)
+		seq_puts(seq, "callsign  dev  mode digipeaters\n");
+	else {
+		struct ax25_route *ax25_rt = v;
+		const char *callsign;
+		int i;
+
+		if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
+			callsign = "default";
+		else
+			callsign = ax2asc(buf, &ax25_rt->callsign);
+
+		seq_printf(seq, "%-9s %-4s",
+			callsign,
+			ax25_rt->dev ? ax25_rt->dev->name : "???");
+
+		switch (ax25_rt->ip_mode) {
+		case 'V':
+			seq_puts(seq, "   vc");
+			break;
+		case 'D':
+			seq_puts(seq, "   dg");
+			break;
+		default:
+			seq_puts(seq, "    *");
+			break;
+		}
+
+		if (ax25_rt->digipeat != NULL)
+			for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
+				seq_printf(seq, " %s",
+				     ax2asc(buf, &ax25_rt->digipeat->calls[i]));
+
+		seq_puts(seq, "\n");
+	}
+	return 0;
+}
+
+const struct seq_operations ax25_rt_seqops = {
+	.start = ax25_rt_seq_start,
+	.next = ax25_rt_seq_next,
+	.stop = ax25_rt_seq_stop,
+	.show = ax25_rt_seq_show,
+};
+#endif
+
+/*
+ *	Find AX.25 route
+ *
+ *	Only routes with a reference count of zero can be destroyed.
+ *	Must be called with ax25_route_lock read locked.
+ */
+ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
+{
+	ax25_route *ax25_spe_rt = NULL;
+	ax25_route *ax25_def_rt = NULL;
+	ax25_route *ax25_rt;
+
+	/*
+	 *	Bind to the physical interface we heard them on, or the default
+	 *	route if none is found;
+	 */
+	for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
+		if (dev == NULL) {
+			if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
+				ax25_spe_rt = ax25_rt;
+			if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
+				ax25_def_rt = ax25_rt;
+		} else {
+			if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
+				ax25_spe_rt = ax25_rt;
+			if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
+				ax25_def_rt = ax25_rt;
+		}
+	}
+
+	ax25_rt = ax25_def_rt;
+	if (ax25_spe_rt != NULL)
+		ax25_rt = ax25_spe_rt;
+
+	return ax25_rt;
+}
+
+/*
+ *	Adjust path: If you specify a default route and want to connect
+ *      a target on the digipeater path but w/o having a special route
+ *	set before, the path has to be truncated from your target on.
+ */
+static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
+{
+	int k;
+
+	for (k = 0; k < digipeat->ndigi; k++) {
+		if (ax25cmp(addr, &digipeat->calls[k]) == 0)
+			break;
+	}
+
+	digipeat->ndigi = k;
+}
+
+
+/*
+ *	Find which interface to use.
+ */
+int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
+{
+	ax25_uid_assoc *user;
+	ax25_route *ax25_rt;
+	int err = 0;
+
+	ax25_route_lock_use();
+	ax25_rt = ax25_get_route(addr, NULL);
+	if (!ax25_rt) {
+		ax25_route_lock_unuse();
+		return -EHOSTUNREACH;
+	}
+	if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
+		err = -EHOSTUNREACH;
+		goto put;
+	}
+
+	user = ax25_findbyuid(current_euid());
+	if (user) {
+		ax25->source_addr = user->call;
+		ax25_uid_put(user);
+	} else {
+		if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
+			err = -EPERM;
+			goto put;
+		}
+		ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
+	}
+
+	if (ax25_rt->digipeat != NULL) {
+		ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
+					 GFP_ATOMIC);
+		if (ax25->digipeat == NULL) {
+			err = -ENOMEM;
+			goto put;
+		}
+		ax25_adjust_path(addr, ax25->digipeat);
+	}
+
+	if (ax25->sk != NULL) {
+		local_bh_disable();
+		bh_lock_sock(ax25->sk);
+		sock_reset_flag(ax25->sk, SOCK_ZAPPED);
+		bh_unlock_sock(ax25->sk);
+		local_bh_enable();
+	}
+
+put:
+	ax25_route_lock_unuse();
+	return err;
+}
+
+struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
+	ax25_address *dest, ax25_digi *digi)
+{
+	unsigned char *bp;
+	int len;
+
+	len = digi->ndigi * AX25_ADDR_LEN;
+
+	if (unlikely(skb_headroom(skb) < len)) {
+		skb = skb_expand_head(skb, len);
+		if (!skb) {
+			printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
+			return NULL;
+		}
+	}
+
+	bp = skb_push(skb, len);
+
+	ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
+
+	return skb;
+}
+
+/*
+ *	Free all memory associated with routing structures.
+ */
+void __exit ax25_rt_free(void)
+{
+	ax25_route *s, *ax25_rt = ax25_route_list;
+
+	write_lock_bh(&ax25_route_lock);
+	while (ax25_rt != NULL) {
+		s       = ax25_rt;
+		ax25_rt = ax25_rt->next;
+
+		kfree(s->digipeat);
+		kfree(s);
+	}
+	write_unlock_bh(&ax25_route_lock);
+}
diff --git a/net/ax25/ax25_std_in.c b/net/ax25/ax25_std_in.c
new file mode 100644
index 000000000..ba176196a
--- /dev/null
+++ b/net/ax25/ax25_std_in.c
@@ -0,0 +1,443 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
+ *
+ * Most of this code is based on the SDL diagrams published in the 7th ARRL
+ * Computer Networking Conference papers. The diagrams have mistakes in them,
+ * but are mostly correct. Before you modify the code could you read the SDL
+ * diagrams as the code is not obvious and probably very easy to break.
+ */
+#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 <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+/*
+ *	State machine for state 1, Awaiting Connection State.
+ *	The handling of the timer(s) is in file ax25_std_timer.c.
+ *	Handling of state 0 and connection release is in ax25.c.
+ */
+static int ax25_std_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
+{
+	switch (frametype) {
+	case AX25_SABM:
+		ax25->modulus = AX25_MODULUS;
+		ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		break;
+
+	case AX25_SABME:
+		ax25->modulus = AX25_EMODULUS;
+		ax25->window  = ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		break;
+
+	case AX25_DISC:
+		ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE);
+		break;
+
+	case AX25_UA:
+		if (pf) {
+			ax25_calculate_rtt(ax25);
+			ax25_stop_t1timer(ax25);
+			ax25_start_t3timer(ax25);
+			ax25_start_idletimer(ax25);
+			ax25->vs      = 0;
+			ax25->va      = 0;
+			ax25->vr      = 0;
+			ax25->state   = AX25_STATE_3;
+			ax25->n2count = 0;
+			if (ax25->sk != NULL) {
+				bh_lock_sock(ax25->sk);
+				ax25->sk->sk_state = TCP_ESTABLISHED;
+				/* For WAIT_SABM connections we will produce an accept ready socket here */
+				if (!sock_flag(ax25->sk, SOCK_DEAD))
+					ax25->sk->sk_state_change(ax25->sk);
+				bh_unlock_sock(ax25->sk);
+			}
+		}
+		break;
+
+	case AX25_DM:
+		if (pf) {
+			if (ax25->modulus == AX25_MODULUS) {
+				ax25_disconnect(ax25, ECONNREFUSED);
+			} else {
+				ax25->modulus = AX25_MODULUS;
+				ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+			}
+		}
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ *	State machine for state 2, Awaiting Release State.
+ *	The handling of the timer(s) is in file ax25_std_timer.c
+ *	Handling of state 0 and connection release is in ax25.c.
+ */
+static int ax25_std_state2_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
+{
+	switch (frametype) {
+	case AX25_SABM:
+	case AX25_SABME:
+		ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE);
+		break;
+
+	case AX25_DISC:
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		ax25_disconnect(ax25, 0);
+		break;
+
+	case AX25_DM:
+	case AX25_UA:
+		if (pf)
+			ax25_disconnect(ax25, 0);
+		break;
+
+	case AX25_I:
+	case AX25_REJ:
+	case AX25_RNR:
+	case AX25_RR:
+		if (pf) ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ *	State machine for state 3, Connected State.
+ *	The handling of the timer(s) is in file ax25_std_timer.c
+ *	Handling of state 0 and connection release is in ax25.c.
+ */
+static int ax25_std_state3_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type)
+{
+	int queued = 0;
+
+	switch (frametype) {
+	case AX25_SABM:
+	case AX25_SABME:
+		if (frametype == AX25_SABM) {
+			ax25->modulus = AX25_MODULUS;
+			ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+		} else {
+			ax25->modulus = AX25_EMODULUS;
+			ax25->window  = ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
+		}
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		ax25_stop_t1timer(ax25);
+		ax25_stop_t2timer(ax25);
+		ax25_start_t3timer(ax25);
+		ax25_start_idletimer(ax25);
+		ax25->condition = 0x00;
+		ax25->vs        = 0;
+		ax25->va        = 0;
+		ax25->vr        = 0;
+		ax25_requeue_frames(ax25);
+		break;
+
+	case AX25_DISC:
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		ax25_disconnect(ax25, 0);
+		break;
+
+	case AX25_DM:
+		ax25_disconnect(ax25, ECONNRESET);
+		break;
+
+	case AX25_RR:
+	case AX25_RNR:
+		if (frametype == AX25_RR)
+			ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
+		else
+			ax25->condition |= AX25_COND_PEER_RX_BUSY;
+		if (type == AX25_COMMAND && pf)
+			ax25_std_enquiry_response(ax25);
+		if (ax25_validate_nr(ax25, nr)) {
+			ax25_check_iframes_acked(ax25, nr);
+		} else {
+			ax25_std_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+		}
+		break;
+
+	case AX25_REJ:
+		ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
+		if (type == AX25_COMMAND && pf)
+			ax25_std_enquiry_response(ax25);
+		if (ax25_validate_nr(ax25, nr)) {
+			ax25_frames_acked(ax25, nr);
+			ax25_calculate_rtt(ax25);
+			ax25_stop_t1timer(ax25);
+			ax25_start_t3timer(ax25);
+			ax25_requeue_frames(ax25);
+		} else {
+			ax25_std_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+		}
+		break;
+
+	case AX25_I:
+		if (!ax25_validate_nr(ax25, nr)) {
+			ax25_std_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+			break;
+		}
+		if (ax25->condition & AX25_COND_PEER_RX_BUSY) {
+			ax25_frames_acked(ax25, nr);
+		} else {
+			ax25_check_iframes_acked(ax25, nr);
+		}
+		if (ax25->condition & AX25_COND_OWN_RX_BUSY) {
+			if (pf) ax25_std_enquiry_response(ax25);
+			break;
+		}
+		if (ns == ax25->vr) {
+			ax25->vr = (ax25->vr + 1) % ax25->modulus;
+			queued = ax25_rx_iframe(ax25, skb);
+			if (ax25->condition & AX25_COND_OWN_RX_BUSY)
+				ax25->vr = ns;	/* ax25->vr - 1 */
+			ax25->condition &= ~AX25_COND_REJECT;
+			if (pf) {
+				ax25_std_enquiry_response(ax25);
+			} else {
+				if (!(ax25->condition & AX25_COND_ACK_PENDING)) {
+					ax25->condition |= AX25_COND_ACK_PENDING;
+					ax25_start_t2timer(ax25);
+				}
+			}
+		} else {
+			if (ax25->condition & AX25_COND_REJECT) {
+				if (pf) ax25_std_enquiry_response(ax25);
+			} else {
+				ax25->condition |= AX25_COND_REJECT;
+				ax25_send_control(ax25, AX25_REJ, pf, AX25_RESPONSE);
+				ax25->condition &= ~AX25_COND_ACK_PENDING;
+			}
+		}
+		break;
+
+	case AX25_FRMR:
+	case AX25_ILLEGAL:
+		ax25_std_establish_data_link(ax25);
+		ax25->state = AX25_STATE_1;
+		break;
+
+	default:
+		break;
+	}
+
+	return queued;
+}
+
+/*
+ *	State machine for state 4, Timer Recovery State.
+ *	The handling of the timer(s) is in file ax25_std_timer.c
+ *	Handling of state 0 and connection release is in ax25.c.
+ */
+static int ax25_std_state4_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type)
+{
+	int queued = 0;
+
+	switch (frametype) {
+	case AX25_SABM:
+	case AX25_SABME:
+		if (frametype == AX25_SABM) {
+			ax25->modulus = AX25_MODULUS;
+			ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+		} else {
+			ax25->modulus = AX25_EMODULUS;
+			ax25->window  = ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
+		}
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		ax25_stop_t1timer(ax25);
+		ax25_stop_t2timer(ax25);
+		ax25_start_t3timer(ax25);
+		ax25_start_idletimer(ax25);
+		ax25->condition = 0x00;
+		ax25->vs        = 0;
+		ax25->va        = 0;
+		ax25->vr        = 0;
+		ax25->state     = AX25_STATE_3;
+		ax25->n2count   = 0;
+		ax25_requeue_frames(ax25);
+		break;
+
+	case AX25_DISC:
+		ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+		ax25_disconnect(ax25, 0);
+		break;
+
+	case AX25_DM:
+		ax25_disconnect(ax25, ECONNRESET);
+		break;
+
+	case AX25_RR:
+	case AX25_RNR:
+		if (frametype == AX25_RR)
+			ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
+		else
+			ax25->condition |= AX25_COND_PEER_RX_BUSY;
+		if (type == AX25_RESPONSE && pf) {
+			ax25_stop_t1timer(ax25);
+			ax25->n2count = 0;
+			if (ax25_validate_nr(ax25, nr)) {
+				ax25_frames_acked(ax25, nr);
+				if (ax25->vs == ax25->va) {
+					ax25_start_t3timer(ax25);
+					ax25->state   = AX25_STATE_3;
+				} else {
+					ax25_requeue_frames(ax25);
+				}
+			} else {
+				ax25_std_nr_error_recovery(ax25);
+				ax25->state = AX25_STATE_1;
+			}
+			break;
+		}
+		if (type == AX25_COMMAND && pf)
+			ax25_std_enquiry_response(ax25);
+		if (ax25_validate_nr(ax25, nr)) {
+			ax25_frames_acked(ax25, nr);
+		} else {
+			ax25_std_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+		}
+		break;
+
+	case AX25_REJ:
+		ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
+		if (pf && type == AX25_RESPONSE) {
+			ax25_stop_t1timer(ax25);
+			ax25->n2count = 0;
+			if (ax25_validate_nr(ax25, nr)) {
+				ax25_frames_acked(ax25, nr);
+				if (ax25->vs == ax25->va) {
+					ax25_start_t3timer(ax25);
+					ax25->state   = AX25_STATE_3;
+				} else {
+					ax25_requeue_frames(ax25);
+				}
+			} else {
+				ax25_std_nr_error_recovery(ax25);
+				ax25->state = AX25_STATE_1;
+			}
+			break;
+		}
+		if (type == AX25_COMMAND && pf)
+			ax25_std_enquiry_response(ax25);
+		if (ax25_validate_nr(ax25, nr)) {
+			ax25_frames_acked(ax25, nr);
+			ax25_requeue_frames(ax25);
+		} else {
+			ax25_std_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+		}
+		break;
+
+	case AX25_I:
+		if (!ax25_validate_nr(ax25, nr)) {
+			ax25_std_nr_error_recovery(ax25);
+			ax25->state = AX25_STATE_1;
+			break;
+		}
+		ax25_frames_acked(ax25, nr);
+		if (ax25->condition & AX25_COND_OWN_RX_BUSY) {
+			if (pf)
+				ax25_std_enquiry_response(ax25);
+			break;
+		}
+		if (ns == ax25->vr) {
+			ax25->vr = (ax25->vr + 1) % ax25->modulus;
+			queued = ax25_rx_iframe(ax25, skb);
+			if (ax25->condition & AX25_COND_OWN_RX_BUSY)
+				ax25->vr = ns;	/* ax25->vr - 1 */
+			ax25->condition &= ~AX25_COND_REJECT;
+			if (pf) {
+				ax25_std_enquiry_response(ax25);
+			} else {
+				if (!(ax25->condition & AX25_COND_ACK_PENDING)) {
+					ax25->condition |= AX25_COND_ACK_PENDING;
+					ax25_start_t2timer(ax25);
+				}
+			}
+		} else {
+			if (ax25->condition & AX25_COND_REJECT) {
+				if (pf) ax25_std_enquiry_response(ax25);
+			} else {
+				ax25->condition |= AX25_COND_REJECT;
+				ax25_send_control(ax25, AX25_REJ, pf, AX25_RESPONSE);
+				ax25->condition &= ~AX25_COND_ACK_PENDING;
+			}
+		}
+		break;
+
+	case AX25_FRMR:
+	case AX25_ILLEGAL:
+		ax25_std_establish_data_link(ax25);
+		ax25->state = AX25_STATE_1;
+		break;
+
+	default:
+		break;
+	}
+
+	return queued;
+}
+
+/*
+ *	Higher level upcall for a LAPB frame
+ */
+int ax25_std_frame_in(ax25_cb *ax25, struct sk_buff *skb, int type)
+{
+	int queued = 0, frametype, ns, nr, pf;
+
+	frametype = ax25_decode(ax25, skb, &ns, &nr, &pf);
+
+	switch (ax25->state) {
+	case AX25_STATE_1:
+		queued = ax25_std_state1_machine(ax25, skb, frametype, pf, type);
+		break;
+	case AX25_STATE_2:
+		queued = ax25_std_state2_machine(ax25, skb, frametype, pf, type);
+		break;
+	case AX25_STATE_3:
+		queued = ax25_std_state3_machine(ax25, skb, frametype, ns, nr, pf, type);
+		break;
+	case AX25_STATE_4:
+		queued = ax25_std_state4_machine(ax25, skb, frametype, ns, nr, pf, type);
+		break;
+	}
+
+	ax25_kick(ax25);
+
+	return queued;
+}
diff --git a/net/ax25/ax25_std_subr.c b/net/ax25/ax25_std_subr.c
new file mode 100644
index 000000000..4c36f1342
--- /dev/null
+++ b/net/ax25/ax25_std_subr.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ */
+#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 <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+/*
+ * The following routines are taken from page 170 of the 7th ARRL Computer
+ * Networking Conference paper, as is the whole state machine.
+ */
+
+void ax25_std_nr_error_recovery(ax25_cb *ax25)
+{
+	ax25_std_establish_data_link(ax25);
+}
+
+void ax25_std_establish_data_link(ax25_cb *ax25)
+{
+	ax25->condition = 0x00;
+	ax25->n2count   = 0;
+
+	if (ax25->modulus == AX25_MODULUS)
+		ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
+	else
+		ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
+
+	ax25_calculate_t1(ax25);
+	ax25_stop_idletimer(ax25);
+	ax25_stop_t3timer(ax25);
+	ax25_stop_t2timer(ax25);
+	ax25_start_t1timer(ax25);
+}
+
+void ax25_std_transmit_enquiry(ax25_cb *ax25)
+{
+	if (ax25->condition & AX25_COND_OWN_RX_BUSY)
+		ax25_send_control(ax25, AX25_RNR, AX25_POLLON, AX25_COMMAND);
+	else
+		ax25_send_control(ax25, AX25_RR, AX25_POLLON, AX25_COMMAND);
+
+	ax25->condition &= ~AX25_COND_ACK_PENDING;
+
+	ax25_calculate_t1(ax25);
+	ax25_start_t1timer(ax25);
+}
+
+void ax25_std_enquiry_response(ax25_cb *ax25)
+{
+	if (ax25->condition & AX25_COND_OWN_RX_BUSY)
+		ax25_send_control(ax25, AX25_RNR, AX25_POLLON, AX25_RESPONSE);
+	else
+		ax25_send_control(ax25, AX25_RR, AX25_POLLON, AX25_RESPONSE);
+
+	ax25->condition &= ~AX25_COND_ACK_PENDING;
+}
+
+void ax25_std_timeout_response(ax25_cb *ax25)
+{
+	if (ax25->condition & AX25_COND_OWN_RX_BUSY)
+		ax25_send_control(ax25, AX25_RNR, AX25_POLLOFF, AX25_RESPONSE);
+	else
+		ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
+
+	ax25->condition &= ~AX25_COND_ACK_PENDING;
+}
diff --git a/net/ax25/ax25_std_timer.c b/net/ax25/ax25_std_timer.c
new file mode 100644
index 000000000..b17da4121
--- /dev/null
+++ b/net/ax25/ax25_std_timer.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
+ */
+#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 <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+void ax25_std_heartbeat_expiry(ax25_cb *ax25)
+{
+	struct sock *sk = ax25->sk;
+
+	if (sk)
+		bh_lock_sock(sk);
+
+	switch (ax25->state) {
+	case AX25_STATE_0:
+	case AX25_STATE_2:
+		/* Magic here: If we listen() and a new link dies before it
+		   is accepted() it isn't 'dead' so doesn't get removed. */
+		if (!sk || sock_flag(sk, SOCK_DESTROY) ||
+		    (sk->sk_state == TCP_LISTEN &&
+		     sock_flag(sk, SOCK_DEAD))) {
+			if (sk) {
+				sock_hold(sk);
+				ax25_destroy_socket(ax25);
+				bh_unlock_sock(sk);
+				/* Ungrab socket and destroy it */
+				sock_put(sk);
+			} else
+				ax25_destroy_socket(ax25);
+			return;
+		}
+		break;
+
+	case AX25_STATE_3:
+	case AX25_STATE_4:
+		/*
+		 * Check the state of the receive buffer.
+		 */
+		if (sk != NULL) {
+			if (atomic_read(&sk->sk_rmem_alloc) <
+			    (sk->sk_rcvbuf >> 1) &&
+			    (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
+				ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
+				ax25->condition &= ~AX25_COND_ACK_PENDING;
+				ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
+				break;
+			}
+		}
+	}
+
+	if (sk)
+		bh_unlock_sock(sk);
+
+	ax25_start_heartbeat(ax25);
+}
+
+void ax25_std_t2timer_expiry(ax25_cb *ax25)
+{
+	if (ax25->condition & AX25_COND_ACK_PENDING) {
+		ax25->condition &= ~AX25_COND_ACK_PENDING;
+		ax25_std_timeout_response(ax25);
+	}
+}
+
+void ax25_std_t3timer_expiry(ax25_cb *ax25)
+{
+	ax25->n2count = 0;
+	ax25_std_transmit_enquiry(ax25);
+	ax25->state   = AX25_STATE_4;
+}
+
+void ax25_std_idletimer_expiry(ax25_cb *ax25)
+{
+	ax25_clear_queues(ax25);
+
+	ax25->n2count = 0;
+	ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+	ax25->state   = AX25_STATE_2;
+
+	ax25_calculate_t1(ax25);
+	ax25_start_t1timer(ax25);
+	ax25_stop_t2timer(ax25);
+	ax25_stop_t3timer(ax25);
+
+	if (ax25->sk != NULL) {
+		bh_lock_sock(ax25->sk);
+		ax25->sk->sk_state     = TCP_CLOSE;
+		ax25->sk->sk_err       = 0;
+		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
+		if (!sock_flag(ax25->sk, SOCK_DEAD)) {
+			ax25->sk->sk_state_change(ax25->sk);
+			sock_set_flag(ax25->sk, SOCK_DEAD);
+		}
+		bh_unlock_sock(ax25->sk);
+	}
+}
+
+void ax25_std_t1timer_expiry(ax25_cb *ax25)
+{
+	switch (ax25->state) {
+	case AX25_STATE_1:
+		if (ax25->n2count == ax25->n2) {
+			if (ax25->modulus == AX25_MODULUS) {
+				ax25_disconnect(ax25, ETIMEDOUT);
+				return;
+			} else {
+				ax25->modulus = AX25_MODULUS;
+				ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
+				ax25->n2count = 0;
+				ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
+			}
+		} else {
+			ax25->n2count++;
+			if (ax25->modulus == AX25_MODULUS)
+				ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
+			else
+				ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
+		}
+		break;
+
+	case AX25_STATE_2:
+		if (ax25->n2count == ax25->n2) {
+			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+			if (!sock_flag(ax25->sk, SOCK_DESTROY))
+				ax25_disconnect(ax25, ETIMEDOUT);
+			return;
+		} else {
+			ax25->n2count++;
+			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
+		}
+		break;
+
+	case AX25_STATE_3:
+		ax25->n2count = 1;
+		ax25_std_transmit_enquiry(ax25);
+		ax25->state   = AX25_STATE_4;
+		break;
+
+	case AX25_STATE_4:
+		if (ax25->n2count == ax25->n2) {
+			ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
+			ax25_disconnect(ax25, ETIMEDOUT);
+			return;
+		} else {
+			ax25->n2count++;
+			ax25_std_transmit_enquiry(ax25);
+		}
+		break;
+	}
+
+	ax25_calculate_t1(ax25);
+	ax25_start_t1timer(ax25);
+}
diff --git a/net/ax25/ax25_subr.c b/net/ax25/ax25_subr.c
new file mode 100644
index 000000000..9ff98f46d
--- /dev/null
+++ b/net/ax25/ax25_subr.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
+ */
+#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/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+/*
+ *	This routine purges all the queues of frames.
+ */
+void ax25_clear_queues(ax25_cb *ax25)
+{
+	skb_queue_purge(&ax25->write_queue);
+	skb_queue_purge(&ax25->ack_queue);
+	skb_queue_purge(&ax25->reseq_queue);
+	skb_queue_purge(&ax25->frag_queue);
+}
+
+/*
+ * This routine purges the input queue of those frames that have been
+ * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
+ * SDL diagram.
+ */
+void ax25_frames_acked(ax25_cb *ax25, unsigned short nr)
+{
+	struct sk_buff *skb;
+
+	/*
+	 * Remove all the ack-ed frames from the ack queue.
+	 */
+	if (ax25->va != nr) {
+		while (skb_peek(&ax25->ack_queue) != NULL && ax25->va != nr) {
+			skb = skb_dequeue(&ax25->ack_queue);
+			kfree_skb(skb);
+			ax25->va = (ax25->va + 1) % ax25->modulus;
+		}
+	}
+}
+
+void ax25_requeue_frames(ax25_cb *ax25)
+{
+	struct sk_buff *skb;
+
+	/*
+	 * Requeue all the un-ack-ed frames on the output queue to be picked
+	 * up by ax25_kick called from the timer. This arrangement handles the
+	 * possibility of an empty output queue.
+	 */
+	while ((skb = skb_dequeue_tail(&ax25->ack_queue)) != NULL)
+		skb_queue_head(&ax25->write_queue, skb);
+}
+
+/*
+ *	Validate that the value of nr is between va and vs. Return true or
+ *	false for testing.
+ */
+int ax25_validate_nr(ax25_cb *ax25, unsigned short nr)
+{
+	unsigned short vc = ax25->va;
+
+	while (vc != ax25->vs) {
+		if (nr == vc) return 1;
+		vc = (vc + 1) % ax25->modulus;
+	}
+
+	if (nr == ax25->vs) return 1;
+
+	return 0;
+}
+
+/*
+ *	This routine is the centralised routine for parsing the control
+ *	information for the different frame formats.
+ */
+int ax25_decode(ax25_cb *ax25, struct sk_buff *skb, int *ns, int *nr, int *pf)
+{
+	unsigned char *frame;
+	int frametype = AX25_ILLEGAL;
+
+	frame = skb->data;
+	*ns = *nr = *pf = 0;
+
+	if (ax25->modulus == AX25_MODULUS) {
+		if ((frame[0] & AX25_S) == 0) {
+			frametype = AX25_I;			/* I frame - carries NR/NS/PF */
+			*ns = (frame[0] >> 1) & 0x07;
+			*nr = (frame[0] >> 5) & 0x07;
+			*pf = frame[0] & AX25_PF;
+		} else if ((frame[0] & AX25_U) == 1) { 	/* S frame - take out PF/NR */
+			frametype = frame[0] & 0x0F;
+			*nr = (frame[0] >> 5) & 0x07;
+			*pf = frame[0] & AX25_PF;
+		} else if ((frame[0] & AX25_U) == 3) { 	/* U frame - take out PF */
+			frametype = frame[0] & ~AX25_PF;
+			*pf = frame[0] & AX25_PF;
+		}
+		skb_pull(skb, 1);
+	} else {
+		if ((frame[0] & AX25_S) == 0) {
+			frametype = AX25_I;			/* I frame - carries NR/NS/PF */
+			*ns = (frame[0] >> 1) & 0x7F;
+			*nr = (frame[1] >> 1) & 0x7F;
+			*pf = frame[1] & AX25_EPF;
+			skb_pull(skb, 2);
+		} else if ((frame[0] & AX25_U) == 1) { 	/* S frame - take out PF/NR */
+			frametype = frame[0] & 0x0F;
+			*nr = (frame[1] >> 1) & 0x7F;
+			*pf = frame[1] & AX25_EPF;
+			skb_pull(skb, 2);
+		} else if ((frame[0] & AX25_U) == 3) { 	/* U frame - take out PF */
+			frametype = frame[0] & ~AX25_PF;
+			*pf = frame[0] & AX25_PF;
+			skb_pull(skb, 1);
+		}
+	}
+
+	return frametype;
+}
+
+/*
+ *	This routine is called when the HDLC layer internally  generates a
+ *	command or  response  for  the remote machine ( eg. RR, UA etc. ).
+ *	Only supervisory or unnumbered frames are processed.
+ */
+void ax25_send_control(ax25_cb *ax25, int frametype, int poll_bit, int type)
+{
+	struct sk_buff *skb;
+	unsigned char  *dptr;
+
+	if ((skb = alloc_skb(ax25->ax25_dev->dev->hard_header_len + 2, GFP_ATOMIC)) == NULL)
+		return;
+
+	skb_reserve(skb, ax25->ax25_dev->dev->hard_header_len);
+
+	skb_reset_network_header(skb);
+
+	/* Assume a response - address structure for DTE */
+	if (ax25->modulus == AX25_MODULUS) {
+		dptr = skb_put(skb, 1);
+		*dptr = frametype;
+		*dptr |= (poll_bit) ? AX25_PF : 0;
+		if ((frametype & AX25_U) == AX25_S)		/* S frames carry NR */
+			*dptr |= (ax25->vr << 5);
+	} else {
+		if ((frametype & AX25_U) == AX25_U) {
+			dptr = skb_put(skb, 1);
+			*dptr = frametype;
+			*dptr |= (poll_bit) ? AX25_PF : 0;
+		} else {
+			dptr = skb_put(skb, 2);
+			dptr[0] = frametype;
+			dptr[1] = (ax25->vr << 1);
+			dptr[1] |= (poll_bit) ? AX25_EPF : 0;
+		}
+	}
+
+	ax25_transmit_buffer(ax25, skb, type);
+}
+
+/*
+ *	Send a 'DM' to an unknown connection attempt, or an invalid caller.
+ *
+ *	Note: src here is the sender, thus it's the target of the DM
+ */
+void ax25_return_dm(struct net_device *dev, ax25_address *src, ax25_address *dest, ax25_digi *digi)
+{
+	struct sk_buff *skb;
+	char *dptr;
+	ax25_digi retdigi;
+
+	if (dev == NULL)
+		return;
+
+	if ((skb = alloc_skb(dev->hard_header_len + 1, GFP_ATOMIC)) == NULL)
+		return;	/* Next SABM will get DM'd */
+
+	skb_reserve(skb, dev->hard_header_len);
+	skb_reset_network_header(skb);
+
+	ax25_digi_invert(digi, &retdigi);
+
+	dptr = skb_put(skb, 1);
+
+	*dptr = AX25_DM | AX25_PF;
+
+	/*
+	 *	Do the address ourselves
+	 */
+	dptr  = skb_push(skb, ax25_addr_size(digi));
+	dptr += ax25_addr_build(dptr, dest, src, &retdigi, AX25_RESPONSE, AX25_MODULUS);
+
+	ax25_queue_xmit(skb, dev);
+}
+
+/*
+ *	Exponential backoff for AX.25
+ */
+void ax25_calculate_t1(ax25_cb *ax25)
+{
+	int n, t = 2;
+
+	switch (ax25->backoff) {
+	case 0:
+		break;
+
+	case 1:
+		t += 2 * ax25->n2count;
+		break;
+
+	case 2:
+		for (n = 0; n < ax25->n2count; n++)
+			t *= 2;
+		if (t > 8) t = 8;
+		break;
+	}
+
+	ax25->t1 = t * ax25->rtt;
+}
+
+/*
+ *	Calculate the Round Trip Time
+ */
+void ax25_calculate_rtt(ax25_cb *ax25)
+{
+	if (ax25->backoff == 0)
+		return;
+
+	if (ax25_t1timer_running(ax25) && ax25->n2count == 0)
+		ax25->rtt = (9 * ax25->rtt + ax25->t1 - ax25_display_timer(&ax25->t1timer)) / 10;
+
+	if (ax25->rtt < AX25_T1CLAMPLO)
+		ax25->rtt = AX25_T1CLAMPLO;
+
+	if (ax25->rtt > AX25_T1CLAMPHI)
+		ax25->rtt = AX25_T1CLAMPHI;
+}
+
+void ax25_disconnect(ax25_cb *ax25, int reason)
+{
+	ax25_clear_queues(ax25);
+
+	if (reason == ENETUNREACH) {
+		del_timer_sync(&ax25->timer);
+		del_timer_sync(&ax25->t1timer);
+		del_timer_sync(&ax25->t2timer);
+		del_timer_sync(&ax25->t3timer);
+		del_timer_sync(&ax25->idletimer);
+	} else {
+		if (ax25->sk && !sock_flag(ax25->sk, SOCK_DESTROY))
+			ax25_stop_heartbeat(ax25);
+		ax25_stop_t1timer(ax25);
+		ax25_stop_t2timer(ax25);
+		ax25_stop_t3timer(ax25);
+		ax25_stop_idletimer(ax25);
+	}
+
+	ax25->state = AX25_STATE_0;
+
+	ax25_link_failed(ax25, reason);
+
+	if (ax25->sk != NULL) {
+		local_bh_disable();
+		bh_lock_sock(ax25->sk);
+		ax25->sk->sk_state     = TCP_CLOSE;
+		ax25->sk->sk_err       = reason;
+		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
+		if (!sock_flag(ax25->sk, SOCK_DEAD)) {
+			ax25->sk->sk_state_change(ax25->sk);
+			sock_set_flag(ax25->sk, SOCK_DEAD);
+		}
+		bh_unlock_sock(ax25->sk);
+		local_bh_enable();
+	}
+}
diff --git a/net/ax25/ax25_timer.c b/net/ax25/ax25_timer.c
new file mode 100644
index 000000000..9f7cb0a7c
--- /dev/null
+++ b/net/ax25/ax25_timer.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Tomi Manninen OH2BNS (oh2bns@sral.fi)
+ * Copyright (C) Darryl Miles G7LED (dlm@g7led.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
+ * Copyright (C) 2002 Ralf Baechle DO1GRB (ralf@gnu.org)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+static void ax25_heartbeat_expiry(struct timer_list *);
+static void ax25_t1timer_expiry(struct timer_list *);
+static void ax25_t2timer_expiry(struct timer_list *);
+static void ax25_t3timer_expiry(struct timer_list *);
+static void ax25_idletimer_expiry(struct timer_list *);
+
+void ax25_setup_timers(ax25_cb *ax25)
+{
+	timer_setup(&ax25->timer, ax25_heartbeat_expiry, 0);
+	timer_setup(&ax25->t1timer, ax25_t1timer_expiry, 0);
+	timer_setup(&ax25->t2timer, ax25_t2timer_expiry, 0);
+	timer_setup(&ax25->t3timer, ax25_t3timer_expiry, 0);
+	timer_setup(&ax25->idletimer, ax25_idletimer_expiry, 0);
+}
+
+void ax25_start_heartbeat(ax25_cb *ax25)
+{
+	mod_timer(&ax25->timer, jiffies + 5 * HZ);
+}
+
+void ax25_start_t1timer(ax25_cb *ax25)
+{
+	mod_timer(&ax25->t1timer, jiffies + ax25->t1);
+}
+
+void ax25_start_t2timer(ax25_cb *ax25)
+{
+	mod_timer(&ax25->t2timer, jiffies + ax25->t2);
+}
+
+void ax25_start_t3timer(ax25_cb *ax25)
+{
+	if (ax25->t3 > 0)
+		mod_timer(&ax25->t3timer, jiffies + ax25->t3);
+	else
+		del_timer(&ax25->t3timer);
+}
+
+void ax25_start_idletimer(ax25_cb *ax25)
+{
+	if (ax25->idle > 0)
+		mod_timer(&ax25->idletimer, jiffies + ax25->idle);
+	else
+		del_timer(&ax25->idletimer);
+}
+
+void ax25_stop_heartbeat(ax25_cb *ax25)
+{
+	del_timer(&ax25->timer);
+}
+
+void ax25_stop_t1timer(ax25_cb *ax25)
+{
+	del_timer(&ax25->t1timer);
+}
+
+void ax25_stop_t2timer(ax25_cb *ax25)
+{
+	del_timer(&ax25->t2timer);
+}
+
+void ax25_stop_t3timer(ax25_cb *ax25)
+{
+	del_timer(&ax25->t3timer);
+}
+
+void ax25_stop_idletimer(ax25_cb *ax25)
+{
+	del_timer(&ax25->idletimer);
+}
+
+int ax25_t1timer_running(ax25_cb *ax25)
+{
+	return timer_pending(&ax25->t1timer);
+}
+
+unsigned long ax25_display_timer(struct timer_list *timer)
+{
+	long delta = timer->expires - jiffies;
+
+	if (!timer_pending(timer))
+		return 0;
+
+	return max(0L, delta);
+}
+
+EXPORT_SYMBOL(ax25_display_timer);
+
+static void ax25_heartbeat_expiry(struct timer_list *t)
+{
+	int proto = AX25_PROTO_STD_SIMPLEX;
+	ax25_cb *ax25 = from_timer(ax25, t, timer);
+
+	if (ax25->ax25_dev)
+		proto = ax25->ax25_dev->values[AX25_VALUES_PROTOCOL];
+
+	switch (proto) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_std_heartbeat_expiry(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		if (ax25->ax25_dev->dama.slave)
+			ax25_ds_heartbeat_expiry(ax25);
+		else
+			ax25_std_heartbeat_expiry(ax25);
+		break;
+#endif
+	}
+}
+
+static void ax25_t1timer_expiry(struct timer_list *t)
+{
+	ax25_cb *ax25 = from_timer(ax25, t, t1timer);
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_std_t1timer_expiry(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		if (!ax25->ax25_dev->dama.slave)
+			ax25_std_t1timer_expiry(ax25);
+		break;
+#endif
+	}
+}
+
+static void ax25_t2timer_expiry(struct timer_list *t)
+{
+	ax25_cb *ax25 = from_timer(ax25, t, t2timer);
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_std_t2timer_expiry(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		if (!ax25->ax25_dev->dama.slave)
+			ax25_std_t2timer_expiry(ax25);
+		break;
+#endif
+	}
+}
+
+static void ax25_t3timer_expiry(struct timer_list *t)
+{
+	ax25_cb *ax25 = from_timer(ax25, t, t3timer);
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_std_t3timer_expiry(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		if (ax25->ax25_dev->dama.slave)
+			ax25_ds_t3timer_expiry(ax25);
+		else
+			ax25_std_t3timer_expiry(ax25);
+		break;
+#endif
+	}
+}
+
+static void ax25_idletimer_expiry(struct timer_list *t)
+{
+	ax25_cb *ax25 = from_timer(ax25, t, idletimer);
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_std_idletimer_expiry(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		if (ax25->ax25_dev->dama.slave)
+			ax25_ds_idletimer_expiry(ax25);
+		else
+			ax25_std_idletimer_expiry(ax25);
+		break;
+#endif
+	}
+}
diff --git a/net/ax25/ax25_uid.c b/net/ax25/ax25_uid.c
new file mode 100644
index 000000000..241e4680e
--- /dev/null
+++ b/net/ax25/ax25_uid.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ */
+
+#include <linux/capability.h>
+#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/spinlock.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/notifier.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/stat.h>
+#include <linux/sysctl.h>
+#include <linux/export.h>
+#include <net/ip.h>
+#include <net/arp.h>
+
+/*
+ *	Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
+ */
+
+static HLIST_HEAD(ax25_uid_list);
+static DEFINE_RWLOCK(ax25_uid_lock);
+
+int ax25_uid_policy;
+
+EXPORT_SYMBOL(ax25_uid_policy);
+
+ax25_uid_assoc *ax25_findbyuid(kuid_t uid)
+{
+	ax25_uid_assoc *ax25_uid, *res = NULL;
+
+	read_lock(&ax25_uid_lock);
+	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
+		if (uid_eq(ax25_uid->uid, uid)) {
+			ax25_uid_hold(ax25_uid);
+			res = ax25_uid;
+			break;
+		}
+	}
+	read_unlock(&ax25_uid_lock);
+
+	return res;
+}
+
+EXPORT_SYMBOL(ax25_findbyuid);
+
+int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
+{
+	ax25_uid_assoc *ax25_uid;
+	ax25_uid_assoc *user;
+	unsigned long res;
+
+	switch (cmd) {
+	case SIOCAX25GETUID:
+		res = -ENOENT;
+		read_lock(&ax25_uid_lock);
+		ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
+			if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
+				res = from_kuid_munged(current_user_ns(), ax25_uid->uid);
+				break;
+			}
+		}
+		read_unlock(&ax25_uid_lock);
+
+		return res;
+
+	case SIOCAX25ADDUID:
+	{
+		kuid_t sax25_kuid;
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+		sax25_kuid = make_kuid(current_user_ns(), sax->sax25_uid);
+		if (!uid_valid(sax25_kuid))
+			return -EINVAL;
+		user = ax25_findbyuid(sax25_kuid);
+		if (user) {
+			ax25_uid_put(user);
+			return -EEXIST;
+		}
+		if (sax->sax25_uid == 0)
+			return -EINVAL;
+		if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
+			return -ENOMEM;
+
+		refcount_set(&ax25_uid->refcount, 1);
+		ax25_uid->uid  = sax25_kuid;
+		ax25_uid->call = sax->sax25_call;
+
+		write_lock(&ax25_uid_lock);
+		hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
+		write_unlock(&ax25_uid_lock);
+
+		return 0;
+	}
+	case SIOCAX25DELUID:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		ax25_uid = NULL;
+		write_lock(&ax25_uid_lock);
+		ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
+			if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
+				break;
+		}
+		if (ax25_uid == NULL) {
+			write_unlock(&ax25_uid_lock);
+			return -ENOENT;
+		}
+		hlist_del_init(&ax25_uid->uid_node);
+		ax25_uid_put(ax25_uid);
+		write_unlock(&ax25_uid_lock);
+
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;	/*NOTREACHED */
+}
+
+#ifdef CONFIG_PROC_FS
+
+static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(ax25_uid_lock)
+{
+	read_lock(&ax25_uid_lock);
+	return seq_hlist_start_head(&ax25_uid_list, *pos);
+}
+
+static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	return seq_hlist_next(v, &ax25_uid_list, pos);
+}
+
+static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
+	__releases(ax25_uid_lock)
+{
+	read_unlock(&ax25_uid_lock);
+}
+
+static int ax25_uid_seq_show(struct seq_file *seq, void *v)
+{
+	char buf[11];
+
+	if (v == SEQ_START_TOKEN)
+		seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
+	else {
+		struct ax25_uid_assoc *pt;
+
+		pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
+		seq_printf(seq, "%6d %s\n",
+			from_kuid_munged(seq_user_ns(seq), pt->uid),
+			ax2asc(buf, &pt->call));
+	}
+	return 0;
+}
+
+const struct seq_operations ax25_uid_seqops = {
+	.start = ax25_uid_seq_start,
+	.next = ax25_uid_seq_next,
+	.stop = ax25_uid_seq_stop,
+	.show = ax25_uid_seq_show,
+};
+#endif
+
+/*
+ *	Free all memory associated with UID/Callsign structures.
+ */
+void __exit ax25_uid_free(void)
+{
+	ax25_uid_assoc *ax25_uid;
+
+	write_lock(&ax25_uid_lock);
+again:
+	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
+		hlist_del_init(&ax25_uid->uid_node);
+		ax25_uid_put(ax25_uid);
+		goto again;
+	}
+	write_unlock(&ax25_uid_lock);
+}
diff --git a/net/ax25/sysctl_net_ax25.c b/net/ax25/sysctl_net_ax25.c
new file mode 100644
index 000000000..2154d004d
--- /dev/null
+++ b/net/ax25/sysctl_net_ax25.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) 1996 Mike Shaver (shaver@zeroknowledge.com)
+ */
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/spinlock.h>
+#include <net/ax25.h>
+
+static int min_ipdefmode[1],    	max_ipdefmode[] = {1};
+static int min_axdefmode[1],            max_axdefmode[] = {1};
+static int min_backoff[1],		max_backoff[] = {2};
+static int min_conmode[1],		max_conmode[] = {2};
+static int min_window[] = {1},		max_window[] = {7};
+static int min_ewindow[] = {1},		max_ewindow[] = {63};
+static int min_t1[] = {1},		max_t1[] = {30000};
+static int min_t2[] = {1},		max_t2[] = {20000};
+static int min_t3[1],			max_t3[] = {3600000};
+static int min_idle[1],			max_idle[] = {65535000};
+static int min_n2[] = {1},		max_n2[] = {31};
+static int min_paclen[] = {1},		max_paclen[] = {512};
+static int min_proto[1],		max_proto[] = { AX25_PROTO_MAX };
+#ifdef CONFIG_AX25_DAMA_SLAVE
+static int min_ds_timeout[1],		max_ds_timeout[] = {65535000};
+#endif
+
+static const struct ctl_table ax25_param_table[] = {
+	{
+		.procname	= "ip_default_mode",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_ipdefmode,
+		.extra2		= &max_ipdefmode
+	},
+	{
+		.procname	= "ax25_default_mode",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_axdefmode,
+		.extra2		= &max_axdefmode
+	},
+	{
+		.procname	= "backoff_type",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_backoff,
+		.extra2		= &max_backoff
+	},
+	{
+		.procname	= "connect_mode",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_conmode,
+		.extra2		= &max_conmode
+	},
+	{
+		.procname	= "standard_window_size",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_window,
+		.extra2		= &max_window
+	},
+	{
+		.procname	= "extended_window_size",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_ewindow,
+		.extra2		= &max_ewindow
+	},
+	{
+		.procname	= "t1_timeout",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_t1,
+		.extra2		= &max_t1
+	},
+	{
+		.procname	= "t2_timeout",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_t2,
+		.extra2		= &max_t2
+	},
+	{
+		.procname	= "t3_timeout",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_t3,
+		.extra2		= &max_t3
+	},
+	{
+		.procname	= "idle_timeout",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_idle,
+		.extra2		= &max_idle
+	},
+	{
+		.procname	= "maximum_retry_count",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_n2,
+		.extra2		= &max_n2
+	},
+	{
+		.procname	= "maximum_packet_length",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_paclen,
+		.extra2		= &max_paclen
+	},
+	{
+		.procname	= "protocol",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_proto,
+		.extra2		= &max_proto
+	},
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	{
+		.procname	= "dama_slave_timeout",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &min_ds_timeout,
+		.extra2		= &max_ds_timeout
+	},
+#endif
+
+	{ }	/* that's all, folks! */
+};
+
+int ax25_register_dev_sysctl(ax25_dev *ax25_dev)
+{
+	char path[sizeof("net/ax25/") + IFNAMSIZ];
+	int k;
+	struct ctl_table *table;
+
+	table = kmemdup(ax25_param_table, sizeof(ax25_param_table), GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	for (k = 0; k < AX25_MAX_VALUES; k++)
+		table[k].data = &ax25_dev->values[k];
+
+	snprintf(path, sizeof(path), "net/ax25/%s", ax25_dev->dev->name);
+	ax25_dev->sysheader = register_net_sysctl(&init_net, path, table);
+	if (!ax25_dev->sysheader) {
+		kfree(table);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void ax25_unregister_dev_sysctl(ax25_dev *ax25_dev)
+{
+	struct ctl_table_header *header = ax25_dev->sysheader;
+	struct ctl_table *table;
+
+	if (header) {
+		ax25_dev->sysheader = NULL;
+		table = header->ctl_table_arg;
+		unregister_net_sysctl_table(header);
+		kfree(table);
+	}
+}