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authorDavid Brownell <david-b@pacbell.net>2006-11-17 02:30:14 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2006-12-01 17:52:02 -0500
commitc957b32406b73ed66d0f20ebab0cab25c848105d (patch)
treea90a76afe8096d071a7819ad91810019c410acc5 /Documentation
parentc67334fbdfbba533af767610cf3fde8a49710e62 (diff)
Documentation/driver-model/platform.txt update/rewrite
This is almost a rewrite of the driver-model/platform.txt documentation; the previous text was obsolete (for several years), evidently it never got updated to match the change from being a PC "legacy_bus" to the more widely used core bus for most embedded systems. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/driver-model/platform.txt204
1 files changed, 118 insertions, 86 deletions
diff --git a/Documentation/driver-model/platform.txt b/Documentation/driver-model/platform.txt
index 5eee3e0bfc4c..9f0bc3bfd776 100644
--- a/Documentation/driver-model/platform.txt
+++ b/Documentation/driver-model/platform.txt
@@ -1,99 +1,131 @@
1Platform Devices and Drivers 1Platform Devices and Drivers
2~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3See <linux/platform_device.h> for the driver model interface to the
4platform bus: platform_device, and platform_driver. This pseudo-bus
5is used to connect devices on busses with minimal infrastructure,
6like those used to integrate peripherals on many system-on-chip
7processors, or some "legacy" PC interconnects; as opposed to large
8formally specified ones like PCI or USB.
9
3 10
4Platform devices 11Platform devices
5~~~~~~~~~~~~~~~~ 12~~~~~~~~~~~~~~~~
6Platform devices are devices that typically appear as autonomous 13Platform devices are devices that typically appear as autonomous
7entities in the system. This includes legacy port-based devices and 14entities in the system. This includes legacy port-based devices and
8host bridges to peripheral buses. 15host bridges to peripheral buses, and most controllers integrated
9 16into system-on-chip platforms. What they usually have in common
10 17is direct addressing from a CPU bus. Rarely, a platform_device will
11Platform drivers 18be connected through a segment of some other kind of bus; but its
12~~~~~~~~~~~~~~~~ 19registers will still be directly addressible.
13Drivers for platform devices are typically very simple and
14unstructured. Either the device was present at a particular I/O port
15and the driver was loaded, or it was not. There was no possibility
16of hotplugging or alternative discovery besides probing at a specific
17I/O address and expecting a specific response.
18 20
21Platform devices are given a name, used in driver binding, and a
22list of resources such as addresses and IRQs.
19 23
20Other Architectures, Modern Firmware, and new Platforms 24struct platform_device {
21~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 25 const char *name;
22These devices are not always at the legacy I/O ports. This is true on 26 u32 id;
23other architectures and on some modern architectures. In most cases, 27 struct device dev;
24the drivers are modified to discover the devices at other well-known 28 u32 num_resources;
25ports for the given platform. However, the firmware in these systems 29 struct resource *resource;
26does usually know where exactly these devices reside, and in some 30};
27cases, it's the only way of discovering them.
28 31
29 32
30The Platform Bus 33Platform drivers
31~~~~~~~~~~~~~~~~
32A platform bus has been created to deal with these issues. First and
33foremost, it groups all the legacy devices under a common bus, and
34gives them a common parent if they don't already have one.
35
36But, besides the organizational benefits, the platform bus can also
37accommodate firmware-based enumeration.
38
39
40Device Discovery
41~~~~~~~~~~~~~~~~ 34~~~~~~~~~~~~~~~~
42The platform bus has no concept of probing for devices. Devices 35Platform drivers follow the standard driver model convention, where
43discovery is left up to either the legacy drivers or the 36discovery/enumeration is handled outside the drivers, and drivers
44firmware. These entities are expected to notify the platform of 37provide probe() and remove() methods. They support power management
45devices that it discovers via the bus's add() callback: 38and shutdown notifications using the standard conventions.
46 39
47 platform_bus.add(parent,bus_id). 40struct platform_driver {
48 41 int (*probe)(struct platform_device *);
49 42 int (*remove)(struct platform_device *);
50Bus IDs 43 void (*shutdown)(struct platform_device *);
51~~~~~~~ 44 int (*suspend)(struct platform_device *, pm_message_t state);
52Bus IDs are the canonical names for the devices. There is no globally 45 int (*suspend_late)(struct platform_device *, pm_message_t state);
53standard addressing mechanism for legacy devices. In the IA-32 world, 46 int (*resume_early)(struct platform_device *);
54we have Pnp IDs to use, as well as the legacy I/O ports. However, 47 int (*resume)(struct platform_device *);
55neither tell what the device really is or have any meaning on other 48 struct device_driver driver;
56platforms. 49};
57 50
58Since both PnP IDs and the legacy I/O ports (and other standard I/O 51Note that probe() should general verify that the specified device hardware
59ports for specific devices) have a 1:1 mapping, we map the 52actually exists; sometimes platform setup code can't be sure. The probing
60platform-specific name or identifier to a generic name (at least 53can use device resources, including clocks, and device platform_data.
61within the scope of the kernel). 54
62 55Platform drivers register themselves the normal way:
63For example, a serial driver might find a device at I/O 0x3f8. The 56
64ACPI firmware might also discover a device with PnP ID (_HID) 57 int platform_driver_register(struct platform_driver *drv);
65PNP0501. Both correspond to the same device and should be mapped to the 58
66canonical name 'serial'. 59Or, in common situations where the device is known not to be hot-pluggable,
67 60the probe() routine can live in an init section to reduce the driver's
68The bus_id field should be a concatenation of the canonical name and 61runtime memory footprint:
69the instance of that type of device. For example, the device at I/O 62
70port 0x3f8 should have a bus_id of "serial0". This places the 63 int platform_driver_probe(struct platform_driver *drv,
71responsibility of enumerating devices of a particular type up to the 64 int (*probe)(struct platform_device *))
72discovery mechanism. But, they are the entity that should know best 65
73(as opposed to the platform bus driver). 66
74 67Device Enumeration
75 68~~~~~~~~~~~~~~~~~~
76Drivers 69As a rule, platform specific (and often board-specific) setup code wil
77~~~~~~~ 70register platform devices:
78Drivers for platform devices should have a name that is the same as 71
79the canonical name of the devices they support. This allows the 72 int platform_device_register(struct platform_device *pdev);
80platform bus driver to do simple matching with the basic data 73
81structures to determine if a driver supports a certain device. 74 int platform_add_devices(struct platform_device **pdevs, int ndev);
82 75
83For example, a legacy serial driver should have a name of 'serial' and 76The general rule is to register only those devices that actually exist,
84register itself with the platform bus. 77but in some cases extra devices might be registered. For example, a kernel
85 78might be configured to work with an external network adapter that might not
86 79be populated on all boards, or likewise to work with an integrated controller
87Driver Binding 80that some boards might not hook up to any peripherals.
88~~~~~~~~~~~~~~ 81
89Legacy drivers assume they are bound to the device once they start up 82In some cases, boot firmware will export tables describing the devices
90and probe an I/O port. Divorcing them from this will be a difficult 83that are populated on a given board. Without such tables, often the
91process. However, that shouldn't prevent us from implementing 84only way for system setup code to set up the correct devices is to build
92firmware-based enumeration. 85a kernel for a specific target board. Such board-specific kernels are
93 86common with embedded and custom systems development.
94The firmware should notify the platform bus about devices before the 87
95legacy drivers have had a chance to load. Once the drivers are loaded, 88In many cases, the memory and IRQ resources associated with the platform
96they driver model core will attempt to bind the driver to any 89device are not enough to let the device's driver work. Board setup code
97previously-discovered devices. Once that has happened, it will be free 90will often provide additional information using the device's platform_data
98to discover any other devices it pleases. 91field to hold additional information.
92
93Embedded systems frequently need one or more clocks for platform devices,
94which are normally kept off until they're actively needed (to save power).
95System setup also associates those clocks with the device, so that that
96calls to clk_get(&pdev->dev, clock_name) return them as needed.
97
98
99Device Naming and Driver Binding
100~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
101The platform_device.dev.bus_id is the canonical name for the devices.
102It's built from two components:
103
104 * platform_device.name ... which is also used to for driver matching.
105
106 * platform_device.id ... the device instance number, or else "-1"
107 to indicate there's only one.
108
109These are catenated, so name/id "serial"/0 indicates bus_id "serial.0", and
110"serial/3" indicates bus_id "serial.3"; both would use the platform_driver
111named "serial". While "my_rtc"/-1 would be bus_id "my_rtc" (no instance id)
112and use the platform_driver called "my_rtc".
113
114Driver binding is performed automatically by the driver core, invoking
115driver probe() after finding a match between device and driver. If the
116probe() succeeds, the driver and device are bound as usual. There are
117three different ways to find such a match:
118
119 - Whenever a device is registered, the drivers for that bus are
120 checked for matches. Platform devices should be registered very
121 early during system boot.
122
123 - When a driver is registered using platform_driver_register(), all
124 unbound devices on that bus are checked for matches. Drivers
125 usually register later during booting, or by module loading.
126
127 - Registering a driver using platform_driver_probe() works just like
128 using platform_driver_register(), except that the the driver won't
129 be probed later if another device registers. (Which is OK, since
130 this interface is only for use with non-hotpluggable devices.)
99 131
generated by cgit v1.2.2 (git 2.25.0) at 2025-02-18 15:45:52 -0500
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/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/sockios.h>
#include <linux/net.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 <asm/uaccess.h>
#include <asm/system.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/netfilter.h>
#include <linux/sysctl.h>
#include <linux/init.h>
#include <linux/spinlock.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(ax25_sk(sk));
}

/*
 *	Socket removal during an interrupt is now safe.
 */
static void ax25_cb_del(ax25_cb *ax25)
{
	if (!hlist_unhashed(&ax25->ax25_node)) {
		spin_lock_bh(&ax25_list_lock);
		hlist_del_init(&ax25->ax25_node);
		spin_unlock_bh(&ax25_list_lock);
		ax25_cb_put(ax25);
	}
}

/*
 *	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 hlist_node *node;

	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
		return;

	spin_lock_bh(&ax25_list_lock);
	ax25_for_each(s, node, &ax25_list) {
		if (s->ax25_dev == ax25_dev) {
			s->ax25_dev = NULL;
			ax25_disconnect(s, ENETUNREACH);
		}
	}
	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 = (struct net_device *)ptr;

	/* 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;
	struct hlist_node *node;

	spin_lock(&ax25_list_lock);
	ax25_for_each(s, node, &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;
	struct hlist_node *node;

	spin_lock(&ax25_list_lock);
	ax25_for_each(s, node, &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(ax25_address *src_addr, ax25_address *dest_addr,
	ax25_digi *digi, struct net_device *dev)
{
	ax25_cb *s;
	struct hlist_node *node;

	spin_lock_bh(&ax25_list_lock);
	ax25_for_each(s, node, &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;
	struct hlist_node *node;

	spin_lock(&ax25_list_lock);
	ax25_for_each(s, node, &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(unsigned long data)
{
	ax25_cb *ax25=(ax25_cb *)data;
	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 = ax25_sk(skb->sk);

				/* Queue the unaccepted socket for death */
				sock_orphan(skb->sk);

				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 (atomic_read(&ax25->sk->sk_wmem_alloc) ||
		    atomic_read(&ax25->sk->sk_rmem_alloc)) {
			/* Defer: outstanding buffers */
			init_timer(&ax25->dtimer);
			ax25->dtimer.expires  = jiffies + 2 * HZ;
			ax25->dtimer.function = ax25_destroy_timer;
			ax25->dtimer.data     = (unsigned long)ax25;
			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;

	if (copy_from_user(&ax25_ctl, arg, sizeof(ax25_ctl)))
		return -EFAULT;

	if ((ax25_dev = ax25_addr_ax25dev(&ax25_ctl.port_addr)) == NULL)
		return -ENODEV;

	if (ax25_ctl.digi_count > AX25_MAX_DIGIS)
		return -EINVAL;

	digi.ndigi = ax25_ctl.digi_count;
	for (k = 0; k < digi.ndigi; k++)
		digi.calls[k] = ax25_ctl.digi_addr[k];

	if ((ax25 = ax25_find_cb(&ax25_ctl.source_addr, &ax25_ctl.dest_addr, &digi, ax25_dev->dev)) == NULL)
		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)
  				return -EINVAL;
  		} else {
  			if (ax25_ctl.arg < 1 || ax25_ctl.arg > 63)
  				return -EINVAL;
  		}
  		ax25->window = ax25_ctl.arg;
  		break;

  	case AX25_T1:
		if (ax25_ctl.arg < 1)
  			return -EINVAL;
  		ax25->rtt = (ax25_ctl.arg * HZ) / 2;
  		ax25->t1  = ax25_ctl.arg * HZ;
  		break;

  	case AX25_T2:
  		if (ax25_ctl.arg < 1)
  			return -EINVAL;
  		ax25->t2 = ax25_ctl.arg * HZ;
  		break;

  	case AX25_N2:
  		if (ax25_ctl.arg < 1 || ax25_ctl.arg > 31)
			return -EINVAL;
  		ax25->n2count = 0;
  		ax25->n2 = ax25_ctl.arg;
  		break;

  	case AX25_T3:
  		if (ax25_ctl.arg < 0)
  			return -EINVAL;
  		ax25->t3 = ax25_ctl.arg * HZ;
  		break;

  	case AX25_IDLE:
  		if (ax25_ctl.arg < 0)
  			return -EINVAL;
  		ax25->idle = ax25_ctl.arg * 60 * HZ;
  		break;

  	case AX25_PACLEN:
  		if (ax25_ctl.arg < 16 || ax25_ctl.arg > 65535)
  			return -EINVAL;
  		ax25->paclen = ax25_ctl.arg;
  		break;

  	default:
  		return -EINVAL;
	  }

	return 0;
}

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;

	atomic_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);

	init_timer(&ax25->timer);
	init_timer(&ax25->t1timer);
	init_timer(&ax25->t2timer);
	init_timer(&ax25->t3timer);
	init_timer(&ax25->idletimer);

	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,
	char __user *optval, int optlen)
{
	struct sock *sk = sock->sk;
	ax25_cb *ax25;
	struct net_device *dev;
	char devname[IFNAMSIZ];
	int opt, res = 0;

	if (level != SOL_AX25)
		return -ENOPROTOOPT;

	if (optlen < sizeof(int))
		return -EINVAL;

	if (get_user(opt, (int __user *)optval))
		return -EFAULT;

	lock_sock(sk);
	ax25 = ax25_sk(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) {
			res = -EINVAL;
			break;
		}
		ax25->rtt = (opt * HZ) / 2;
		ax25->t1  = opt * HZ;
		break;

	case AX25_T2:
		if (opt < 1) {
			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) {
			res = -EINVAL;
			break;
		}
		ax25->t3 = opt * HZ;
		break;

	case AX25_IDLE:
		if (opt < 0) {
			res = -EINVAL;
			break;
		}
		ax25->idle = opt * 60 * HZ;
		break;

	case AX25_BACKOFF:
		if (opt < 0 || 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)
			optlen=IFNAMSIZ;
		if (copy_from_user(devname, optval, optlen)) {
		res = -EFAULT;
			break;
		}

		dev = dev_get_by_name(devname);
		if (dev == NULL) {
			res = -ENODEV;
			break;
		}

		if (sk->sk_type == SOCK_SEQPACKET &&
		   (sock->state != SS_UNCONNECTED ||
		    sk->sk_state == TCP_LISTEN)) {
			res = -EADDRNOTAVAIL;
			dev_put(dev);
			break;
		}

		ax25->ax25_dev = ax25_dev_ax25dev(dev);
		ax25_fillin_cb(ax25, ax25->ax25_dev);
		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 = ax25_sk(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) {
			strlcpy(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 sock),
};

static int ax25_create(struct socket *sock, int protocol)
{
	struct sock *sk;
	ax25_cb *ax25;

	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;
#endif
#ifdef CONFIG_ROSE_MODULE
		case AX25_P_ROSE:
			if (ax25_protocol_is_registered(AX25_P_ROSE))
				return -ESOCKTNOSUPPORT;
#endif
		default:
			break;
		}
		break;

	case SOCK_RAW:
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

	if ((sk = sk_alloc(PF_AX25, GFP_ATOMIC, &ax25_proto, 1)) == NULL)
		return -ENOMEM;

	ax25 = sk->sk_protinfo = 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;

	if ((sk = sk_alloc(PF_AX25, GFP_ATOMIC, osk->sk_prot, 1)) == 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_destruct = ax25_free_sock;
	sk->sk_type     = osk->sk_type;
	sk->sk_socket   = osk->sk_socket;
	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;
	sk->sk_sleep    = osk->sk_sleep;
	sock_copy_flags(sk, osk);

	oax25 = ax25_sk(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) {
		if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
			sk_free(sk);
			ax25_cb_put(ax25);
			return NULL;
		}

		memcpy(ax25->digipeat, oax25->digipeat, sizeof(ax25_digi));
	}

	sk->sk_protinfo = ax25;
	ax25->sk    = sk;

	return sk;
}

static int ax25_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	ax25_cb *ax25;

	if (sk == NULL)
		return 0;

	sock_hold(sk);
	sock_orphan(sk);
	lock_sock(sk);
	ax25 = ax25_sk(sk);

	if (sk->sk_type == SOCK_SEQPACKET) {
		switch (ax25->state) {
		case AX25_STATE_0:
			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);
			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);
	}

	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 */
		if ((addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * 6) ||
		    (addr_len > sizeof(struct full_sockaddr_ax25))) {
			return -EINVAL;
	}

		printk(KERN_WARNING "ax25_bind(): %s uses old (6 digipeater) socket structure.\n",
			current->comm);
	}

	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 = ax25_sk(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 != NULL)
		ax25_fillin_cb(ax25, ax25_dev);

done:
	ax25_cb_add(ax25);
	sock_reset_flag(sk, SOCK_ZAPPED);

out:
	release_sock(sk);

	return 0;
}

/*
 *	FIXME: nonblock behaviour looks like it may have a bug.
 */
static int ax25_connect(struct socket *sock, struct sockaddr *uaddr,
	int addr_len, int flags)
{
	struct sock *sk = sock->sk;
	ax25_cb *ax25 = ax25_sk(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 */
		printk(KERN_WARNING "ax25_connect(): %s uses obsolete socket structure\n",
			current->comm);
	}
	else if (addr_len != sizeof(struct full_sockaddr_ax25)) {
		/* support for old structure may go away some time */
		if ((addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * 6) ||
		    (addr_len > sizeof(struct full_sockaddr_ax25))) {
			return -EINVAL;
		}

		printk(KERN_WARNING "ax25_connect(): %s uses old (6 digipeater) socket structure.\n",
			current->comm);
	}

	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;

		case TCP_ESTABLISHED: /* connection established */
			sock->state = SS_CONNECTED;
			goto out;

		case TCP_CLOSE: /* connection refused */
			sock->state = SS_UNCONNECTED;
			err = -ECONNREFUSED;
			goto out;
		}
	}

	if (sk->sk_state == TCP_ESTABLISHED && sk->sk_type == SOCK_SEQPACKET) {
		err = -EISCONN;	/* No reconnect on a seqpacket socket */
		goto out;
	}

	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) {
			err = -EINVAL;
			goto out;
		}

		if ((digi = kmalloc(sizeof(ax25_digi), GFP_KERNEL)) == NULL) {
			err = -ENOBUFS;
			goto out;
		}

		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;
		}

		ax25_fillin_cb(ax25, ax25->ax25_dev);
		ax25_cb_add(ax25);
	} else {
		if (ax25->ax25_dev == NULL) {
			kfree(digi);
			err = -EHOSTUNREACH;
			goto out;
		}
	}

	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;
	}

	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;
	}

	/* 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;
	}

	if (sk->sk_state == TCP_SYN_SENT) {
		struct task_struct *tsk = current;
		DECLARE_WAITQUEUE(wait, tsk);

		add_wait_queue(sk->sk_sleep, &wait);
		for (;;) {
			if (sk->sk_state != TCP_SYN_SENT)
				break;
			set_current_state(TASK_INTERRUPTIBLE);
			release_sock(sk);
			if (!signal_pending(tsk)) {
				schedule();
				lock_sock(sk);
				continue;
			}
			current->state = TASK_RUNNING;
			remove_wait_queue(sk->sk_sleep, &wait);
			return -ERESTARTSYS;
		}
		current->state = TASK_RUNNING;
		remove_wait_queue(sk->sk_sleep, &wait);
	}

	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;
	}

	sock->state = SS_CONNECTED;

	err=0;
out:
	release_sock(sk);

	return err;
}


static int ax25_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct task_struct *tsk = current;
	DECLARE_WAITQUEUE(wait, tsk);
	struct sk_buff *skb;
	struct sock *newsk;
	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
	 */
	add_wait_queue(sk->sk_sleep, &wait);
	for (;;) {
		skb = skb_dequeue(&sk->sk_receive_queue);
		if (skb)
			break;

		release_sock(sk);
		current->state = TASK_INTERRUPTIBLE;
		if (flags & O_NONBLOCK) {
			current->state = TASK_RUNNING;
			remove_wait_queue(sk->sk_sleep, &wait);
			return -EWOULDBLOCK;
		}
		if (!signal_pending(tsk)) {
			schedule();
			lock_sock(sk);
			continue;
		}
		current->state = TASK_RUNNING;
		remove_wait_queue(sk->sk_sleep, &wait);
		return -ERESTARTSYS;
	}
	current->state = TASK_RUNNING;
	remove_wait_queue(sk->sk_sleep, &wait);

	newsk		 = skb->sk;
	newsk->sk_socket = newsock;
	newsk->sk_sleep	 = &newsock->wait;

	/* Now attach up the new socket */
	kfree_skb(skb);
	sk->sk_ack_backlog--;
	newsock->sk    = newsk;
	newsock->state = SS_CONNECTED;

out:
	release_sock(sk);

	return err;
}

static int ax25_getname(struct socket *sock, struct sockaddr *uaddr,
	int *uaddr_len, 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;

	lock_sock(sk);
	ax25 = ax25_sk(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;
		fsa->fsa_ax25.sax25_ndigis = 0;

		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;
		}
	}
	*uaddr_len = sizeof (struct full_sockaddr_ax25);

out:
	release_sock(sk);

	return err;
}

static int ax25_sendmsg(struct kiocb *iocb, struct socket *sock,
			struct msghdr *msg, size_t len)
{
	struct sockaddr_ax25 *usax = (struct sockaddr_ax25 *)msg->msg_name;
	struct sock *sk = sock->sk;
	struct sockaddr_ax25 sax;
	struct sk_buff *skb;
	ax25_digi dtmp, *dp;
	unsigned char *asmptr;
	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 = ax25_sk(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)) {
			printk(KERN_WARNING "ax25_sendmsg(): %s uses obsolete socket structure\n",
				current->comm);
		}
		else if (addr_len != sizeof(struct full_sockaddr_ax25)) {
			/* support for old structure may go away some time */
			if ((addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * 6) ||
		    	    (addr_len > sizeof(struct full_sockaddr_ax25))) {
		    		err = -EINVAL;
				goto out;
			}

			printk(KERN_WARNING "ax25_sendmsg(): %s uses old (6 digipeater) socket structure.\n",
				current->comm);
		}

		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) {
				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;
	}

	SOCK_DEBUG(sk, "AX.25: sendto: Addresses built.\n");

	/* Build a packet */
	SOCK_DEBUG(sk, "AX.25: sendto: building packet.\n");

	/* 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);

	SOCK_DEBUG(sk, "AX.25: Appending user data\n");

	/* User data follows immediately after the AX.25 data */
	if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
		err = -EFAULT;
		kfree_skb(skb);
		goto out;
	}

	skb->nh.raw = skb->data;

	/* Add the PID if one is not supplied by the user in the skb */
	if (!ax25->pidincl) {
		asmptr  = skb_push(skb, 1);
		*asmptr = sk->sk_protocol;
	}

	SOCK_DEBUG(sk, "AX.25: Transmitting buffer\n");

	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;
	}

	asmptr = skb_push(skb, 1 + ax25_addr_size(dp));

	SOCK_DEBUG(sk, "Building AX.25 Header (dp=%p).\n", dp);

	if (dp != NULL)
		SOCK_DEBUG(sk, "Num digipeaters=%d\n", dp->ndigi);

	/* Build an AX.25 header */
	asmptr += (lv = ax25_addr_build(asmptr, &ax25->source_addr,
					&sax.sax25_call, dp,
					AX25_COMMAND, AX25_MODULUS));

	SOCK_DEBUG(sk, "Built header (%d bytes)\n",lv);

	skb->h.raw = asmptr;

	SOCK_DEBUG(sk, "base=%p pos=%p\n", skb->data, asmptr);

	*asmptr = 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 kiocb *iocb, struct socket *sock,
	struct msghdr *msg, size_t size, int flags)
{
	struct sock *sk = sock->sk;
	struct sk_buff *skb;
	int copied;
	int err = 0;

	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;
	}

	/* Now we can treat all alike */
	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
	                        flags & MSG_DONTWAIT, &err);
	if (skb == NULL)
		goto out;

	if (!ax25_sk(sk)->pidincl)
		skb_pull(skb, 1);		/* Remove PID */

	skb->h.raw = skb->data;
	copied     = skb->len;

	if (copied > size) {
		copied = size;
		msg->msg_flags |= MSG_TRUNC;
	}

	skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);

	if (msg->msg_namelen != 0) {
		struct sockaddr_ax25 *sax = (struct sockaddr_ax25 *)msg->msg_name;
		ax25_digi digi;
		ax25_address src;

		ax25_addr_parse(skb->mac.raw+1, skb->data-skb->mac.raw-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);

	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 - atomic_read(&sk->sk_wmem_alloc);
		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 SIOCGSTAMP:
		res = sock_get_timestamp(sk, 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 > 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 = ax25_sk(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     = atomic_read(&sk->sk_rmem_alloc);
		ax25_info.snd_q     = atomic_read(&sk->sk_wmem_alloc);
		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)
{
	struct ax25_cb *ax25;
	struct hlist_node *node;
	int i = 0;

	spin_lock_bh(&ax25_list_lock);
	ax25_for_each(ax25, node, &ax25_list) {
		if (i == *pos)
			return ax25;
		++i;
	}
	return NULL;
}

static void *ax25_info_next(struct seq_file *seq, void *v, loff_t *pos)
{
	++*pos;