// 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)
  {
  	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;

  
  	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
  		return;
  
  	spin_lock_bh(&ax25_list_lock);

  again:

  	ax25_for_each(s, &ax25_list) {

  		if (s->ax25_dev == ax25_dev) {
  			s->ax25_dev = NULL;

  			spin_unlock_bh(&ax25_list_lock);

  			ax25_disconnect(s, ENETUNREACH);

  			spin_lock_bh(&ax25_list_lock);
  
  			/* 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(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_dev = ax25_addr_ax25dev(&ax25_ctl.port_addr)) == NULL)
  		return -ENODEV;
  
  	if (ax25_ctl.digi_count > AX25_MAX_DIGIS)
  		return -EINVAL;

  	if (ax25_ctl.arg > ULONG_MAX / HZ && ax25_ctl.cmd != AX25_KILL)
  		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)

  				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_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 long 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 > ULONG_MAX / HZ) {

  			res = -EINVAL;
  			break;
  		}

  		ax25->rtt = (opt * HZ) >> 1;

  		ax25->t1  = opt * HZ;
  		break;
  
  	case AX25_T2:

  		if (opt < 1 || opt > ULONG_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 > ULONG_MAX / HZ) {

  			res = -EINVAL;
  			break;
  		}
  		ax25->t3 = opt * HZ;
  		break;
  
  	case AX25_IDLE:

  		if (opt > ULONG_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) {
  			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 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;
  #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;
  
  	if (sk == NULL)
  		return 0;
  
  	sock_hold(sk);
  	sock_orphan(sk);
  	lock_sock(sk);

  	ax25 = sk_to_ax25(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);

  			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);
  	}
  
  	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 != NULL)
  		ax25_fillin_cb(ax25, ax25_dev);
  
  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
  ",
  			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;
  	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 (!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);
  
  	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
  ",
  					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
  ",

  			   sk_wmem_alloc_get(ax25->sk),
  			   sk_rmem_alloc_get(ax25->sk),

  			   sock_i_ino(ax25->sk));

  	} else {
  		seq_puts(seq, " * * *
  ");
  	}
  	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);