/*
   *	X.25 Packet Layer release 002
   *
   *	This is ALPHA test software. This code may break your machine,
   *	randomly fail to work with new releases, misbehave and/or generally

   *	screw up. It might even work.

   *
   *	This code REQUIRES 2.1.15 or higher
   *
   *	This module:
   *		This module 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.
   *
   *	History
   *	X.25 001	Jonathan Naylor	Started coding.
   *	X.25 002	Jonathan Naylor	Centralised disconnect handling.
   *					New timer architecture.
   *	2000-03-11	Henner Eisen	MSG_EOR handling more POSIX compliant.

   *	2000-03-22	Daniela Squassoni Allowed disabling/enabling of
   *					  facilities negotiation and increased

   *					  the throughput upper limit.
   *	2000-08-27	Arnaldo C. Melo s/suser/capable/ + micro cleanups

   *	2000-09-04	Henner Eisen	Set sock->state in x25_accept().

   *					Fixed x25_output() related skb leakage.
   *	2000-10-02	Henner Eisen	Made x25_kick() single threaded per socket.
   *	2000-10-27	Henner Eisen    MSG_DONTWAIT for fragment allocation.
   *	2000-11-14	Henner Eisen    Closing datalink from NETDEV_GOING_DOWN
   *	2002-10-06	Arnaldo C. Melo Get rid of cli/sti, move proc stuff to
   *					x25_proc.c, using seq_file

   *	2005-04-02	Shaun Pereira	Selective sub address matching
   *					with call user data

   *	2005-04-15	Shaun Pereira	Fast select with no restriction on
   *					response

   */

  #include <linux/module.h>

  #include <linux/capability.h>

  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/timer.h>
  #include <linux/string.h>
  #include <linux/net.h>
  #include <linux/netdevice.h>
  #include <linux/if_arp.h>
  #include <linux/skbuff.h>

  #include <linux/slab.h>

  #include <net/sock.h>

  #include <net/tcp_states.h>

  #include <asm/uaccess.h>
  #include <linux/fcntl.h>
  #include <linux/termios.h>	/* For TIOCINQ/OUTQ */
  #include <linux/notifier.h>
  #include <linux/init.h>

  #include <linux/compat.h>

  #include <linux/ctype.h>

  #include <net/x25.h>

  #include <net/compat.h>

  
  int sysctl_x25_restart_request_timeout = X25_DEFAULT_T20;
  int sysctl_x25_call_request_timeout    = X25_DEFAULT_T21;
  int sysctl_x25_reset_request_timeout   = X25_DEFAULT_T22;
  int sysctl_x25_clear_request_timeout   = X25_DEFAULT_T23;
  int sysctl_x25_ack_holdback_timeout    = X25_DEFAULT_T2;

  int sysctl_x25_forward                 = 0;

  
  HLIST_HEAD(x25_list);
  DEFINE_RWLOCK(x25_list_lock);

  static const struct proto_ops x25_proto_ops;

  
  static struct x25_address null_x25_address = {"               "};

  #ifdef CONFIG_COMPAT
  struct compat_x25_subscrip_struct {
  	char device[200-sizeof(compat_ulong_t)];
  	compat_ulong_t global_facil_mask;
  	compat_uint_t extended;
  };
  #endif

  
  int x25_parse_address_block(struct sk_buff *skb,
  		struct x25_address *called_addr,
  		struct x25_address *calling_addr)
  {
  	unsigned char len;
  	int needed;
  	int rc;

  	if (!pskb_may_pull(skb, 1)) {

  		/* packet has no address block */
  		rc = 0;
  		goto empty;
  	}
  
  	len = *skb->data;
  	needed = 1 + (len >> 4) + (len & 0x0f);

  	if (!pskb_may_pull(skb, needed)) {

  		/* packet is too short to hold the addresses it claims
  		   to hold */
  		rc = -1;
  		goto empty;
  	}
  
  	return x25_addr_ntoa(skb->data, called_addr, calling_addr);
  
  empty:
  	*called_addr->x25_addr = 0;
  	*calling_addr->x25_addr = 0;
  
  	return rc;
  }

  int x25_addr_ntoa(unsigned char *p, struct x25_address *called_addr,
  		  struct x25_address *calling_addr)
  {

  	unsigned int called_len, calling_len;

  	char *called, *calling;

  	unsigned int i;

  
  	called_len  = (*p >> 0) & 0x0F;
  	calling_len = (*p >> 4) & 0x0F;
  
  	called  = called_addr->x25_addr;
  	calling = calling_addr->x25_addr;
  	p++;
  
  	for (i = 0; i < (called_len + calling_len); i++) {
  		if (i < called_len) {
  			if (i % 2 != 0) {
  				*called++ = ((*p >> 0) & 0x0F) + '0';
  				p++;
  			} else {
  				*called++ = ((*p >> 4) & 0x0F) + '0';
  			}
  		} else {
  			if (i % 2 != 0) {
  				*calling++ = ((*p >> 0) & 0x0F) + '0';
  				p++;
  			} else {
  				*calling++ = ((*p >> 4) & 0x0F) + '0';
  			}
  		}
  	}
  
  	*called = *calling = '\0';
  
  	return 1 + (called_len + calling_len + 1) / 2;
  }
  
  int x25_addr_aton(unsigned char *p, struct x25_address *called_addr,
  		  struct x25_address *calling_addr)
  {
  	unsigned int called_len, calling_len;
  	char *called, *calling;
  	int i;
  
  	called  = called_addr->x25_addr;
  	calling = calling_addr->x25_addr;
  
  	called_len  = strlen(called);
  	calling_len = strlen(calling);
  
  	*p++ = (calling_len << 4) | (called_len << 0);
  
  	for (i = 0; i < (called_len + calling_len); i++) {
  		if (i < called_len) {
  			if (i % 2 != 0) {
  				*p |= (*called++ - '0') << 0;
  				p++;
  			} else {
  				*p = 0x00;
  				*p |= (*called++ - '0') << 4;
  			}
  		} else {
  			if (i % 2 != 0) {
  				*p |= (*calling++ - '0') << 0;
  				p++;
  			} else {
  				*p = 0x00;
  				*p |= (*calling++ - '0') << 4;
  			}
  		}
  	}
  
  	return 1 + (called_len + calling_len + 1) / 2;
  }
  
  /*
   *	Socket removal during an interrupt is now safe.
   */
  static void x25_remove_socket(struct sock *sk)
  {
  	write_lock_bh(&x25_list_lock);
  	sk_del_node_init(sk);
  	write_unlock_bh(&x25_list_lock);
  }
  
  /*
   *	Kill all bound sockets on a dropped device.
   */
  static void x25_kill_by_device(struct net_device *dev)
  {
  	struct sock *s;
  	struct hlist_node *node;
  
  	write_lock_bh(&x25_list_lock);
  
  	sk_for_each(s, node, &x25_list)
  		if (x25_sk(s)->neighbour && x25_sk(s)->neighbour->dev == dev)
  			x25_disconnect(s, ENETUNREACH, 0, 0);
  
  	write_unlock_bh(&x25_list_lock);
  }
  
  /*
   *	Handle device status changes.
   */
  static int x25_device_event(struct notifier_block *this, unsigned long event,
  			    void *ptr)
  {
  	struct net_device *dev = ptr;
  	struct x25_neigh *nb;

  	if (!net_eq(dev_net(dev), &init_net))

  		return NOTIFY_DONE;

  	if (dev->type == ARPHRD_X25

  #if IS_ENABLED(CONFIG_LLC)

  	 || dev->type == ARPHRD_ETHER
  #endif
  	 ) {
  		switch (event) {

  		case NETDEV_UP:
  			x25_link_device_up(dev);
  			break;
  		case NETDEV_GOING_DOWN:
  			nb = x25_get_neigh(dev);
  			if (nb) {
  				x25_terminate_link(nb);
  				x25_neigh_put(nb);
  			}
  			break;
  		case NETDEV_DOWN:
  			x25_kill_by_device(dev);
  			x25_route_device_down(dev);
  			x25_link_device_down(dev);
  			break;

  		}
  	}
  
  	return NOTIFY_DONE;
  }
  
  /*
   *	Add a socket to the bound sockets list.
   */
  static void x25_insert_socket(struct sock *sk)
  {
  	write_lock_bh(&x25_list_lock);
  	sk_add_node(sk, &x25_list);
  	write_unlock_bh(&x25_list_lock);
  }
  
  /*
   *	Find a socket that wants to accept the Call Request we just
   *	received. Check the full list for an address/cud match.
   *	If no cuds match return the next_best thing, an address match.
   *	Note: if a listening socket has cud set it must only get calls
   *	with matching cud.
   */

  static struct sock *x25_find_listener(struct x25_address *addr,
  					struct sk_buff *skb)

  {
  	struct sock *s;
  	struct sock *next_best;
  	struct hlist_node *node;
  
  	read_lock_bh(&x25_list_lock);
  	next_best = NULL;
  
  	sk_for_each(s, node, &x25_list)
  		if ((!strcmp(addr->x25_addr,

  			x25_sk(s)->source_addr.x25_addr) ||
  				!strcmp(addr->x25_addr,
  					null_x25_address.x25_addr)) &&
  					s->sk_state == TCP_LISTEN) {

  			/*
  			 * Found a listening socket, now check the incoming
  			 * call user data vs this sockets call user data
  			 */

  			if (x25_sk(s)->cudmatchlength > 0 &&
  				skb->len >= x25_sk(s)->cudmatchlength) {

  				if((memcmp(x25_sk(s)->calluserdata.cuddata,
  					skb->data,

  					x25_sk(s)->cudmatchlength)) == 0) {
  					sock_hold(s);
  					goto found;
  				 }
  			} else

  				next_best = s;

  		}
  	if (next_best) {
  		s = next_best;
  		sock_hold(s);
  		goto found;
  	}
  	s = NULL;
  found:
  	read_unlock_bh(&x25_list_lock);
  	return s;
  }
  
  /*
   *	Find a connected X.25 socket given my LCI and neighbour.
   */
  static struct sock *__x25_find_socket(unsigned int lci, struct x25_neigh *nb)
  {
  	struct sock *s;
  	struct hlist_node *node;
  
  	sk_for_each(s, node, &x25_list)
  		if (x25_sk(s)->lci == lci && x25_sk(s)->neighbour == nb) {
  			sock_hold(s);
  			goto found;
  		}
  	s = NULL;
  found:
  	return s;
  }
  
  struct sock *x25_find_socket(unsigned int lci, struct x25_neigh *nb)
  {
  	struct sock *s;
  
  	read_lock_bh(&x25_list_lock);
  	s = __x25_find_socket(lci, nb);
  	read_unlock_bh(&x25_list_lock);
  	return s;
  }
  
  /*
   *	Find a unique LCI for a given device.
   */
  static unsigned int x25_new_lci(struct x25_neigh *nb)
  {
  	unsigned int lci = 1;
  	struct sock *sk;
  
  	read_lock_bh(&x25_list_lock);
  
  	while ((sk = __x25_find_socket(lci, nb)) != NULL) {
  		sock_put(sk);
  		if (++lci == 4096) {
  			lci = 0;
  			break;
  		}
  	}
  
  	read_unlock_bh(&x25_list_lock);
  	return lci;
  }
  
  /*
   *	Deferred destroy.
   */

  static void __x25_destroy_socket(struct sock *);

  
  /*
   *	handler for deferred kills.
   */
  static void x25_destroy_timer(unsigned long data)
  {

  	x25_destroy_socket_from_timer((struct sock *)data);

  }
  
  /*
   *	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.
   *	Not static as it's used by the timer
   */

  static void __x25_destroy_socket(struct sock *sk)

  {
  	struct sk_buff *skb;

  	x25_stop_heartbeat(sk);
  	x25_stop_timer(sk);
  
  	x25_remove_socket(sk);
  	x25_clear_queues(sk);		/* Flush the queues */
  
  	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
  		if (skb->sk != sk) {		/* A pending connection */
  			/*
  			 * Queue the unaccepted socket for death
  			 */

  			skb->sk->sk_state = TCP_LISTEN;

  			sock_set_flag(skb->sk, SOCK_DEAD);
  			x25_start_heartbeat(skb->sk);
  			x25_sk(skb->sk)->state = X25_STATE_0;
  		}
  
  		kfree_skb(skb);
  	}

  	if (sk_has_allocations(sk)) {

  		/* Defer: outstanding buffers */
  		sk->sk_timer.expires  = jiffies + 10 * HZ;
  		sk->sk_timer.function = x25_destroy_timer;
  		sk->sk_timer.data = (unsigned long)sk;
  		add_timer(&sk->sk_timer);
  	} else {
  		/* drop last reference so sock_put will free */
  		__sock_put(sk);
  	}

  }

  void x25_destroy_socket_from_timer(struct sock *sk)
  {
  	sock_hold(sk);
  	bh_lock_sock(sk);
  	__x25_destroy_socket(sk);
  	bh_unlock_sock(sk);
  	sock_put(sk);
  }

  /*
   *	Handling for system calls applied via the various interfaces to a
   *	X.25 socket object.
   */
  
  static int x25_setsockopt(struct socket *sock, int level, int optname,

  			  char __user *optval, unsigned int optlen)

  {
  	int opt;
  	struct sock *sk = sock->sk;
  	int rc = -ENOPROTOOPT;
  
  	if (level != SOL_X25 || optname != X25_QBITINCL)
  		goto out;
  
  	rc = -EINVAL;
  	if (optlen < sizeof(int))
  		goto out;
  
  	rc = -EFAULT;
  	if (get_user(opt, (int __user *)optval))
  		goto out;

  	if (opt)
  		set_bit(X25_Q_BIT_FLAG, &x25_sk(sk)->flags);
  	else
  		clear_bit(X25_Q_BIT_FLAG, &x25_sk(sk)->flags);

  	rc = 0;
  out:
  	return rc;
  }
  
  static int x25_getsockopt(struct socket *sock, int level, int optname,
  			  char __user *optval, int __user *optlen)
  {
  	struct sock *sk = sock->sk;
  	int val, len, rc = -ENOPROTOOPT;

  	if (level != SOL_X25 || optname != X25_QBITINCL)
  		goto out;
  
  	rc = -EFAULT;
  	if (get_user(len, optlen))
  		goto out;
  
  	len = min_t(unsigned int, len, sizeof(int));
  
  	rc = -EINVAL;
  	if (len < 0)
  		goto out;

  	rc = -EFAULT;
  	if (put_user(len, optlen))
  		goto out;

  	val = test_bit(X25_Q_BIT_FLAG, &x25_sk(sk)->flags);

  	rc = copy_to_user(optval, &val, len) ? -EFAULT : 0;
  out:
  	return rc;
  }
  
  static int x25_listen(struct socket *sock, int backlog)
  {
  	struct sock *sk = sock->sk;
  	int rc = -EOPNOTSUPP;

  	lock_sock(sk);

  	if (sk->sk_state != TCP_LISTEN) {
  		memset(&x25_sk(sk)->dest_addr, 0, X25_ADDR_LEN);
  		sk->sk_max_ack_backlog = backlog;
  		sk->sk_state           = TCP_LISTEN;
  		rc = 0;
  	}

  	release_sock(sk);

  
  	return rc;
  }
  
  static struct proto x25_proto = {
  	.name	  = "X25",
  	.owner	  = THIS_MODULE,
  	.obj_size = sizeof(struct x25_sock),
  };

  static struct sock *x25_alloc_socket(struct net *net)

  {
  	struct x25_sock *x25;

  	struct sock *sk = sk_alloc(net, AF_X25, GFP_ATOMIC, &x25_proto);

  
  	if (!sk)
  		goto out;
  
  	sock_init_data(NULL, sk);
  
  	x25 = x25_sk(sk);
  	skb_queue_head_init(&x25->ack_queue);
  	skb_queue_head_init(&x25->fragment_queue);
  	skb_queue_head_init(&x25->interrupt_in_queue);
  	skb_queue_head_init(&x25->interrupt_out_queue);
  out:
  	return sk;
  }

  static int x25_create(struct net *net, struct socket *sock, int protocol,
  		      int kern)

  {
  	struct sock *sk;
  	struct x25_sock *x25;

  	int rc = -EAFNOSUPPORT;

  	if (!net_eq(net, &init_net))

  		goto out;
  
  	rc = -ESOCKTNOSUPPORT;
  	if (sock->type != SOCK_SEQPACKET)
  		goto out;

  	rc = -EINVAL;
  	if (protocol)

  		goto out;

  	rc = -ENOBUFS;

  	if ((sk = x25_alloc_socket(net)) == NULL)

  		goto out;
  
  	x25 = x25_sk(sk);
  
  	sock_init_data(sock, sk);
  
  	x25_init_timers(sk);
  
  	sock->ops    = &x25_proto_ops;
  	sk->sk_protocol = protocol;
  	sk->sk_backlog_rcv = x25_backlog_rcv;
  
  	x25->t21   = sysctl_x25_call_request_timeout;
  	x25->t22   = sysctl_x25_reset_request_timeout;
  	x25->t23   = sysctl_x25_clear_request_timeout;
  	x25->t2    = sysctl_x25_ack_holdback_timeout;
  	x25->state = X25_STATE_0;

  	x25->cudmatchlength = 0;

  	set_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);	/* normally no cud  */

  							/* on call accept   */

  
  	x25->facilities.winsize_in  = X25_DEFAULT_WINDOW_SIZE;
  	x25->facilities.winsize_out = X25_DEFAULT_WINDOW_SIZE;
  	x25->facilities.pacsize_in  = X25_DEFAULT_PACKET_SIZE;
  	x25->facilities.pacsize_out = X25_DEFAULT_PACKET_SIZE;

  	x25->facilities.throughput  = 0;	/* by default don't negotiate
  						   throughput */

  	x25->facilities.reverse     = X25_DEFAULT_REVERSE;

  	x25->dte_facilities.calling_len = 0;
  	x25->dte_facilities.called_len = 0;
  	memset(x25->dte_facilities.called_ae, '\0',
  			sizeof(x25->dte_facilities.called_ae));
  	memset(x25->dte_facilities.calling_ae, '\0',
  			sizeof(x25->dte_facilities.calling_ae));

  	rc = 0;
  out:
  	return rc;
  }
  
  static struct sock *x25_make_new(struct sock *osk)
  {
  	struct sock *sk = NULL;
  	struct x25_sock *x25, *ox25;
  
  	if (osk->sk_type != SOCK_SEQPACKET)
  		goto out;

  	if ((sk = x25_alloc_socket(sock_net(osk))) == NULL)

  		goto out;
  
  	x25 = x25_sk(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;

  	sk->sk_backlog_rcv = osk->sk_backlog_rcv;

  	sock_copy_flags(sk, osk);

  
  	ox25 = x25_sk(osk);
  	x25->t21        = ox25->t21;
  	x25->t22        = ox25->t22;
  	x25->t23        = ox25->t23;
  	x25->t2         = ox25->t2;

  	x25->flags	= ox25->flags;

  	x25->facilities = ox25->facilities;

  	x25->dte_facilities = ox25->dte_facilities;

  	x25->cudmatchlength = ox25->cudmatchlength;

  	clear_bit(X25_INTERRUPT_FLAG, &x25->flags);

  	x25_init_timers(sk);
  out:
  	return sk;
  }
  
  static int x25_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  	struct x25_sock *x25;
  
  	if (!sk)

  		return 0;

  
  	x25 = x25_sk(sk);

  	sock_hold(sk);
  	lock_sock(sk);

  	switch (x25->state) {
  
  		case X25_STATE_0:
  		case X25_STATE_2:
  			x25_disconnect(sk, 0, 0, 0);

  			__x25_destroy_socket(sk);

  			goto out;
  
  		case X25_STATE_1:
  		case X25_STATE_3:
  		case X25_STATE_4:
  			x25_clear_queues(sk);
  			x25_write_internal(sk, X25_CLEAR_REQUEST);
  			x25_start_t23timer(sk);
  			x25->state = X25_STATE_2;
  			sk->sk_state	= TCP_CLOSE;
  			sk->sk_shutdown	|= SEND_SHUTDOWN;
  			sk->sk_state_change(sk);
  			sock_set_flag(sk, SOCK_DEAD);
  			sock_set_flag(sk, SOCK_DESTROY);
  			break;
  	}

  	sock_orphan(sk);

  out:

  	release_sock(sk);
  	sock_put(sk);

  	return 0;
  }
  
  static int x25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
  {
  	struct sock *sk = sock->sk;
  	struct sockaddr_x25 *addr = (struct sockaddr_x25 *)uaddr;

  	int len, i, rc = 0;

  
  	if (!sock_flag(sk, SOCK_ZAPPED) ||
  	    addr_len != sizeof(struct sockaddr_x25) ||

  	    addr->sx25_family != AF_X25) {
  		rc = -EINVAL;
  		goto out;
  	}

  	len = strlen(addr->sx25_addr.x25_addr);
  	for (i = 0; i < len; i++) {
  		if (!isdigit(addr->sx25_addr.x25_addr[i])) {
  			rc = -EINVAL;
  			goto out;
  		}
  	}

  	lock_sock(sk);

  	x25_sk(sk)->source_addr = addr->sx25_addr;
  	x25_insert_socket(sk);
  	sock_reset_flag(sk, SOCK_ZAPPED);

  	release_sock(sk);

  	SOCK_DEBUG(sk, "x25_bind: socket is bound
  ");

  out:

  	return rc;

  }
  
  static int x25_wait_for_connection_establishment(struct sock *sk)
  {
  	DECLARE_WAITQUEUE(wait, current);

  	int rc;

  	add_wait_queue_exclusive(sk_sleep(sk), &wait);

  	for (;;) {
  		__set_current_state(TASK_INTERRUPTIBLE);
  		rc = -ERESTARTSYS;
  		if (signal_pending(current))
  			break;
  		rc = sock_error(sk);
  		if (rc) {
  			sk->sk_socket->state = SS_UNCONNECTED;
  			break;
  		}
  		rc = 0;
  		if (sk->sk_state != TCP_ESTABLISHED) {
  			release_sock(sk);
  			schedule();
  			lock_sock(sk);
  		} else
  			break;
  	}
  	__set_current_state(TASK_RUNNING);

  	remove_wait_queue(sk_sleep(sk), &wait);

  	return rc;
  }
  
  static int x25_connect(struct socket *sock, struct sockaddr *uaddr,
  		       int addr_len, int flags)
  {
  	struct sock *sk = sock->sk;
  	struct x25_sock *x25 = x25_sk(sk);
  	struct sockaddr_x25 *addr = (struct sockaddr_x25 *)uaddr;
  	struct x25_route *rt;
  	int rc = 0;
  
  	lock_sock(sk);
  	if (sk->sk_state == TCP_ESTABLISHED && sock->state == SS_CONNECTING) {
  		sock->state = SS_CONNECTED;
  		goto out; /* Connect completed during a ERESTARTSYS event */
  	}
  
  	rc = -ECONNREFUSED;
  	if (sk->sk_state == TCP_CLOSE && sock->state == SS_CONNECTING) {
  		sock->state = SS_UNCONNECTED;
  		goto out;
  	}
  
  	rc = -EISCONN;	/* No reconnect on a seqpacket socket */
  	if (sk->sk_state == TCP_ESTABLISHED)
  		goto out;

  	sk->sk_state   = TCP_CLOSE;

  	sock->state = SS_UNCONNECTED;
  
  	rc = -EINVAL;
  	if (addr_len != sizeof(struct sockaddr_x25) ||
  	    addr->sx25_family != AF_X25)
  		goto out;
  
  	rc = -ENETUNREACH;
  	rt = x25_get_route(&addr->sx25_addr);
  	if (!rt)
  		goto out;
  
  	x25->neighbour = x25_get_neigh(rt->dev);
  	if (!x25->neighbour)
  		goto out_put_route;
  
  	x25_limit_facilities(&x25->facilities, x25->neighbour);
  
  	x25->lci = x25_new_lci(x25->neighbour);
  	if (!x25->lci)
  		goto out_put_neigh;
  
  	rc = -EINVAL;
  	if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
  		goto out_put_neigh;
  
  	if (!strcmp(x25->source_addr.x25_addr, null_x25_address.x25_addr))
  		memset(&x25->source_addr, '\0', X25_ADDR_LEN);
  
  	x25->dest_addr = addr->sx25_addr;
  
  	/* Move to connecting socket, start sending Connect Requests */
  	sock->state   = SS_CONNECTING;
  	sk->sk_state  = TCP_SYN_SENT;
  
  	x25->state = X25_STATE_1;
  
  	x25_write_internal(sk, X25_CALL_REQUEST);
  
  	x25_start_heartbeat(sk);
  	x25_start_t21timer(sk);
  
  	/* Now the loop */
  	rc = -EINPROGRESS;
  	if (sk->sk_state != TCP_ESTABLISHED && (flags & O_NONBLOCK))
  		goto out_put_neigh;
  
  	rc = x25_wait_for_connection_establishment(sk);
  	if (rc)
  		goto out_put_neigh;
  
  	sock->state = SS_CONNECTED;
  	rc = 0;
  out_put_neigh:
  	if (rc)
  		x25_neigh_put(x25->neighbour);
  out_put_route:
  	x25_route_put(rt);
  out:
  	release_sock(sk);
  	return rc;
  }

  static int x25_wait_for_data(struct sock *sk, long timeout)

  {
  	DECLARE_WAITQUEUE(wait, current);
  	int rc = 0;

  	add_wait_queue_exclusive(sk_sleep(sk), &wait);

  	for (;;) {
  		__set_current_state(TASK_INTERRUPTIBLE);
  		if (sk->sk_shutdown & RCV_SHUTDOWN)
  			break;
  		rc = -ERESTARTSYS;
  		if (signal_pending(current))
  			break;
  		rc = -EAGAIN;
  		if (!timeout)
  			break;
  		rc = 0;
  		if (skb_queue_empty(&sk->sk_receive_queue)) {
  			release_sock(sk);
  			timeout = schedule_timeout(timeout);
  			lock_sock(sk);
  		} else
  			break;
  	}
  	__set_current_state(TASK_RUNNING);

  	remove_wait_queue(sk_sleep(sk), &wait);

  	return rc;
  }

  static int x25_accept(struct socket *sock, struct socket *newsock, int flags)
  {
  	struct sock *sk = sock->sk;
  	struct sock *newsk;
  	struct sk_buff *skb;
  	int rc = -EINVAL;

  	if (!sk)

  		goto out;
  
  	rc = -EOPNOTSUPP;
  	if (sk->sk_type != SOCK_SEQPACKET)
  		goto out;
  
  	lock_sock(sk);

  	rc = -EINVAL;
  	if (sk->sk_state != TCP_LISTEN)
  		goto out2;

  	rc = x25_wait_for_data(sk, sk->sk_rcvtimeo);
  	if (rc)
  		goto out2;
  	skb = skb_dequeue(&sk->sk_receive_queue);
  	rc = -EINVAL;
  	if (!skb->sk)
  		goto out2;
  	newsk		 = skb->sk;

  	sock_graft(newsk, newsock);

  
  	/* Now attach up the new socket */
  	skb->sk = NULL;
  	kfree_skb(skb);
  	sk->sk_ack_backlog--;

  	newsock->state = SS_CONNECTED;
  	rc = 0;
  out2:
  	release_sock(sk);
  out:
  	return rc;
  }
  
  static int x25_getname(struct socket *sock, struct sockaddr *uaddr,
  		       int *uaddr_len, int peer)
  {
  	struct sockaddr_x25 *sx25 = (struct sockaddr_x25 *)uaddr;
  	struct sock *sk = sock->sk;
  	struct x25_sock *x25 = x25_sk(sk);

  	int rc = 0;

  
  	if (peer) {

  		if (sk->sk_state != TCP_ESTABLISHED) {
  			rc = -ENOTCONN;
  			goto out;
  		}

  		sx25->sx25_addr = x25->dest_addr;
  	} else
  		sx25->sx25_addr = x25->source_addr;
  
  	sx25->sx25_family = AF_X25;
  	*uaddr_len = sizeof(*sx25);

  out:

  	return rc;
  }

  int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb,
  			unsigned int lci)
  {
  	struct sock *sk;
  	struct sock *make;
  	struct x25_sock *makex25;
  	struct x25_address source_addr, dest_addr;
  	struct x25_facilities facilities;

  	struct x25_dte_facilities dte_facilities;

  	int len, addr_len, rc;

  
  	/*
  	 *	Remove the LCI and frame type.
  	 */
  	skb_pull(skb, X25_STD_MIN_LEN);
  
  	/*
  	 *	Extract the X.25 addresses and convert them to ASCII strings,
  	 *	and remove them.

  	 *
  	 *	Address block is mandatory in call request packets

  	 */

  	addr_len = x25_parse_address_block(skb, &source_addr, &dest_addr);
  	if (addr_len <= 0)
  		goto out_clear_request;

  	skb_pull(skb, addr_len);

  
  	/*
  	 *	Get the length of the facilities, skip past them for the moment
  	 *	get the call user data because this is needed to determine
  	 *	the correct listener

  	 *
  	 *	Facilities length is mandatory in call request packets

  	 */

  	if (!pskb_may_pull(skb, 1))

  		goto out_clear_request;

  	len = skb->data[0] + 1;

  	if (!pskb_may_pull(skb, len))

  		goto out_clear_request;

  	skb_pull(skb,len);
  
  	/*

  	 *	Ensure that the amount of call user data is valid.
  	 */
  	if (skb->len > X25_MAX_CUD_LEN)
  		goto out_clear_request;
  
  	/*

  	 *	Get all the call user data so it can be used in
  	 *	x25_find_listener and skb_copy_from_linear_data up ahead.
  	 */
  	if (!pskb_may_pull(skb, skb->len))
  		goto out_clear_request;
  
  	/*

  	 *	Find a listener for the particular address/cud pair.
  	 */

  	sk = x25_find_listener(&source_addr,skb);
  	skb_push(skb,len);

  	if (sk != NULL && sk_acceptq_is_full(sk)) {
  		goto out_sock_put;
  	}

  	/*

  	 *	We dont have any listeners for this incoming call.
  	 *	Try forwarding it.

  	 */

  	if (sk == NULL) {
  		skb_push(skb, addr_len + X25_STD_MIN_LEN);

  		if (sysctl_x25_forward &&
  				x25_forward_call(&dest_addr, nb, skb, lci) > 0)

  		{
  			/* Call was forwarded, dont process it any more */
  			kfree_skb(skb);
  			rc = 1;
  			goto out;
  		} else {
  			/* No listeners, can't forward, clear the call */
  			goto out_clear_request;
  		}
  	}

  
  	/*
  	 *	Try to reach a compromise on the requested facilities.
  	 */

  	len = x25_negotiate_facilities(skb, sk, &facilities, &dte_facilities);
  	if (len == -1)

  		goto out_sock_put;
  
  	/*
  	 * current neighbour/link might impose additional limits
  	 * on certain facilties
  	 */
  
  	x25_limit_facilities(&facilities, nb);
  
  	/*
  	 *	Try to create a new socket.
  	 */
  	make = x25_make_new(sk);
  	if (!make)
  		goto out_sock_put;
  
  	/*
  	 *	Remove the facilities
  	 */
  	skb_pull(skb, len);
  
  	skb->sk     = make;
  	make->sk_state = TCP_ESTABLISHED;
  
  	makex25 = x25_sk(make);
  	makex25->lci           = lci;
  	makex25->dest_addr     = dest_addr;
  	makex25->source_addr   = source_addr;
  	makex25->neighbour     = nb;
  	makex25->facilities    = facilities;

  	makex25->dte_facilities= dte_facilities;

  	makex25->vc_facil_mask = x25_sk(sk)->vc_facil_mask;

  	/* ensure no reverse facil on accept */
  	makex25->vc_facil_mask &= ~X25_MASK_REVERSE;

  	/* ensure no calling address extension on accept */
  	makex25->vc_facil_mask &= ~X25_MASK_CALLING_AE;

  	makex25->cudmatchlength = x25_sk(sk)->cudmatchlength;

  	/* Normally all calls are accepted immediately */
  	if (test_bit(X25_ACCPT_APPRV_FLAG, &makex25->flags)) {

  		x25_write_internal(make, X25_CALL_ACCEPTED);
  		makex25->state = X25_STATE_3;
  	}

  	/*
  	 *	Incoming Call User Data.
  	 */

  	skb_copy_from_linear_data(skb, makex25->calluserdata.cuddata, skb->len);
  	makex25->calluserdata.cudlength = skb->len;

  	sk->sk_ack_backlog++;
  
  	x25_insert_socket(make);
  
  	skb_queue_head(&sk->sk_receive_queue, skb);
  
  	x25_start_heartbeat(make);
  
  	if (!sock_flag(sk, SOCK_DEAD))
  		sk->sk_data_ready(sk, skb->len);
  	rc = 1;
  	sock_put(sk);
  out:
  	return rc;
  out_sock_put:
  	sock_put(sk);
  out_clear_request:
  	rc = 0;
  	x25_transmit_clear_request(nb, lci, 0x01);
  	goto out;
  }
  
  static int x25_sendmsg(struct kiocb *iocb, struct socket *sock,
  		       struct msghdr *msg, size_t len)
  {
  	struct sock *sk = sock->sk;
  	struct x25_sock *x25 = x25_sk(sk);
  	struct sockaddr_x25 *usx25 = (struct sockaddr_x25 *)msg->msg_name;
  	struct sockaddr_x25 sx25;
  	struct sk_buff *skb;
  	unsigned char *asmptr;
  	int noblock = msg->msg_flags & MSG_DONTWAIT;
  	size_t size;
  	int qbit = 0, rc = -EINVAL;

  	lock_sock(sk);

  	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_OOB|MSG_EOR|MSG_CMSG_COMPAT))
  		goto out;
  
  	/* we currently don't support segmented records at the user interface */
  	if (!(msg->msg_flags & (MSG_EOR|MSG_OOB)))
  		goto out;
  
  	rc = -EADDRNOTAVAIL;
  	if (sock_flag(sk, SOCK_ZAPPED))
  		goto out;
  
  	rc = -EPIPE;
  	if (sk->sk_shutdown & SEND_SHUTDOWN) {
  		send_sig(SIGPIPE, current, 0);
  		goto out;
  	}
  
  	rc = -ENETUNREACH;
  	if (!x25->neighbour)
  		goto out;
  
  	if (usx25) {
  		rc = -EINVAL;
  		if (msg->msg_namelen < sizeof(sx25))
  			goto out;
  		memcpy(&sx25, usx25, sizeof(sx25));
  		rc = -EISCONN;
  		if (strcmp(x25->dest_addr.x25_addr, sx25.sx25_addr.x25_addr))
  			goto out;
  		rc = -EINVAL;
  		if (sx25.sx25_family != AF_X25)
  			goto out;
  	} else {
  		/*
  		 *	FIXME 1003.1g - if the socket is like this because
  		 *	it has become closed (not started closed) we ought
  		 *	to SIGPIPE, EPIPE;
  		 */
  		rc = -ENOTCONN;
  		if (sk->sk_state != TCP_ESTABLISHED)
  			goto out;
  
  		sx25.sx25_family = AF_X25;
  		sx25.sx25_addr   = x25->dest_addr;
  	}

  	/* Sanity check the packet size */
  	if (len > 65535) {
  		rc = -EMSGSIZE;
  		goto out;
  	}

  	SOCK_DEBUG(sk, "x25_sendmsg: sendto: Addresses built.
  ");
  
  	/* Build a packet */
  	SOCK_DEBUG(sk, "x25_sendmsg: sendto: building packet.
  ");
  
  	if ((msg->msg_flags & MSG_OOB) && len > 32)
  		len = 32;
  
  	size = len + X25_MAX_L2_LEN + X25_EXT_MIN_LEN;

  	release_sock(sk);

  	skb = sock_alloc_send_skb(sk, size, noblock, &rc);

  	lock_sock(sk);

  	if (!skb)
  		goto out;
  	X25_SKB_CB(skb)->flags = msg->msg_flags;
  
  	skb_reserve(skb, X25_MAX_L2_LEN + X25_EXT_MIN_LEN);
  
  	/*
  	 *	Put the data on the end
  	 */
  	SOCK_DEBUG(sk, "x25_sendmsg: Copying user data
  ");

  	skb_reset_transport_header(skb);
  	skb_put(skb, len);

  	rc = memcpy_fromiovec(skb_transport_header(skb), msg->msg_iov, len);

  	if (rc)
  		goto out_kfree_skb;
  
  	/*
  	 *	If the Q BIT Include socket option is in force, the first
  	 *	byte of the user data is the logical value of the Q Bit.
  	 */

  	if (test_bit(X25_Q_BIT_FLAG, &x25->flags)) {

  		if (!pskb_may_pull(skb, 1))
  			goto out_kfree_skb;

  		qbit = skb->data[0];
  		skb_pull(skb, 1);
  	}
  
  	/*
  	 *	Push down the X.25 header
  	 */
  	SOCK_DEBUG(sk, "x25_sendmsg: Building X.25 Header.
  ");
  
  	if (msg->msg_flags & MSG_OOB) {
  		if (x25->neighbour->extended) {
  			asmptr    = skb_push(skb, X25_STD_MIN_LEN);
  			*asmptr++ = ((x25->lci >> 8) & 0x0F) | X25_GFI_EXTSEQ;
  			*asmptr++ = (x25->lci >> 0) & 0xFF;
  			*asmptr++ = X25_INTERRUPT;
  		} else {
  			asmptr    = skb_push(skb, X25_STD_MIN_LEN);
  			*asmptr++ = ((x25->lci >> 8) & 0x0F) | X25_GFI_STDSEQ;
  			*asmptr++ = (x25->lci >> 0) & 0xFF;
  			*asmptr++ = X25_INTERRUPT;
  		}
  	} else {
  		if (x25->neighbour->extended) {
  			/* Build an Extended X.25 header */
  			asmptr    = skb_push(skb, X25_EXT_MIN_LEN);
  			*asmptr++ = ((x25->lci >> 8) & 0x0F) | X25_GFI_EXTSEQ;
  			*asmptr++ = (x25->lci >> 0) & 0xFF;
  			*asmptr++ = X25_DATA;
  			*asmptr++ = X25_DATA;
  		} else {
  			/* Build an Standard X.25 header */
  			asmptr    = skb_push(skb, X25_STD_MIN_LEN);
  			*asmptr++ = ((x25->lci >> 8) & 0x0F) | X25_GFI_STDSEQ;
  			*asmptr++ = (x25->lci >> 0) & 0xFF;
  			*asmptr++ = X25_DATA;
  		}
  
  		if (qbit)
  			skb->data[0] |= X25_Q_BIT;
  	}
  
  	SOCK_DEBUG(sk, "x25_sendmsg: Built header.
  ");
  	SOCK_DEBUG(sk, "x25_sendmsg: Transmitting buffer
  ");
  
  	rc = -ENOTCONN;
  	if (sk->sk_state != TCP_ESTABLISHED)
  		goto out_kfree_skb;
  
  	if (msg->msg_flags & MSG_OOB)
  		skb_queue_tail(&x25->interrupt_out_queue, skb);
  	else {

  		rc = x25_output(sk, skb);
  		len = rc;
  		if (rc < 0)

  			kfree_skb(skb);

  		else if (test_bit(X25_Q_BIT_FLAG, &x25->flags))

  			len++;
  	}

  	x25_kick(sk);

  	rc = len;
  out:

  	release_sock(sk);

  	return rc;
  out_kfree_skb:
  	kfree_skb(skb);
  	goto out;
  }
  
  
  static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
  		       struct msghdr *msg, size_t size,
  		       int flags)
  {
  	struct sock *sk = sock->sk;
  	struct x25_sock *x25 = x25_sk(sk);
  	struct sockaddr_x25 *sx25 = (struct sockaddr_x25 *)msg->msg_name;
  	size_t copied;

  	int qbit, header_len;

  	struct sk_buff *skb;
  	unsigned char *asmptr;
  	int rc = -ENOTCONN;

  	lock_sock(sk);

  
  	if (x25->neighbour == NULL)
  		goto out;
  
  	header_len = x25->neighbour->extended ?
  		X25_EXT_MIN_LEN : X25_STD_MIN_LEN;

  	/*
  	 * This works for seqpacket too. The receiver has ordered the queue for
  	 * us! We do one quick check first though
  	 */
  	if (sk->sk_state != TCP_ESTABLISHED)
  		goto out;
  
  	if (flags & MSG_OOB) {
  		rc = -EINVAL;
  		if (sock_flag(sk, SOCK_URGINLINE) ||
  		    !skb_peek(&x25->interrupt_in_queue))
  			goto out;
  
  		skb = skb_dequeue(&x25->interrupt_in_queue);

  		if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
  			goto out_free_dgram;

  		skb_pull(skb, X25_STD_MIN_LEN);
  
  		/*
  		 *	No Q bit information on Interrupt data.
  		 */

  		if (test_bit(X25_Q_BIT_FLAG, &x25->flags)) {

  			asmptr  = skb_push(skb, 1);
  			*asmptr = 0x00;
  		}
  
  		msg->msg_flags |= MSG_OOB;
  	} else {
  		/* Now we can treat all alike */

  		release_sock(sk);

  		skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
  					flags & MSG_DONTWAIT, &rc);

  		lock_sock(sk);

  		if (!skb)
  			goto out;

  		if (!pskb_may_pull(skb, header_len))
  			goto out_free_dgram;

  		qbit = (skb->data[0] & X25_Q_BIT) == X25_Q_BIT;

  		skb_pull(skb, header_len);

  		if (test_bit(X25_Q_BIT_FLAG, &x25->flags)) {

  			asmptr  = skb_push(skb, 1);
  			*asmptr = qbit;
  		}
  	}

  	skb_reset_transport_header(skb);

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

  	/* Currently, each datagram always contains a complete record */

  	msg->msg_flags |= MSG_EOR;
  
  	rc = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
  	if (rc)
  		goto out_free_dgram;
  
  	if (sx25) {
  		sx25->sx25_family = AF_X25;
  		sx25->sx25_addr   = x25->dest_addr;
  	}
  
  	msg->msg_namelen = sizeof(struct sockaddr_x25);

  	x25_check_rbuf(sk);

  	rc = copied;
  out_free_dgram:
  	skb_free_datagram(sk, skb);
  out:

  	release_sock(sk);

  	return rc;
  }
  
  
  static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
  {
  	struct sock *sk = sock->sk;
  	struct x25_sock *x25 = x25_sk(sk);
  	void __user *argp = (void __user *)arg;
  	int rc;
  
  	switch (cmd) {

  	case TIOCOUTQ: {
  		int amount;
  
  		amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
  		if (amount < 0)
  			amount = 0;
  		rc = put_user(amount, (unsigned int __user *)argp);
  		break;
  	}

  	case TIOCINQ: {
  		struct sk_buff *skb;
  		int amount = 0;
  		/*
  		 * These two are safe on a single CPU system as
  		 * only user tasks fiddle here
  		 */
  		lock_sock(sk);
  		if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
  			amount = skb->len;
  		release_sock(sk);
  		rc = put_user(amount, (unsigned int __user *)argp);
  		break;
  	}

  	case SIOCGSTAMP:
  		rc = -EINVAL;
  		if (sk)
  			rc = sock_get_timestamp(sk,

  						(struct timeval __user *)argp);

  		break;
  	case SIOCGSTAMPNS:
  		rc = -EINVAL;
  		if (sk)
  			rc = sock_get_timestampns(sk,
  					(struct timespec __user *)argp);
  		break;
  	case SIOCGIFADDR:
  	case SIOCSIFADDR:
  	case SIOCGIFDSTADDR:
  	case SIOCSIFDSTADDR:
  	case SIOCGIFBRDADDR:
  	case SIOCSIFBRDADDR:
  	case SIOCGIFNETMASK:
  	case SIOCSIFNETMASK:
  	case SIOCGIFMETRIC:
  	case SIOCSIFMETRIC:
  		rc = -EINVAL;
  		break;
  	case SIOCADDRT:
  	case SIOCDELRT:
  		rc = -EPERM;
  		if (!capable(CAP_NET_ADMIN))

  			break;

  		rc = x25_route_ioctl(cmd, argp);
  		break;
  	case SIOCX25GSUBSCRIP:
  		rc = x25_subscr_ioctl(cmd, argp);
  		break;
  	case SIOCX25SSUBSCRIP:
  		rc = -EPERM;
  		if (!capable(CAP_NET_ADMIN))

  			break;

  		rc = x25_subscr_ioctl(cmd, argp);
  		break;
  	case SIOCX25GFACILITIES: {
  		lock_sock(sk);
  		rc = copy_to_user(argp, &x25->facilities,
  				  sizeof(x25->facilities))
  			? -EFAULT : 0;
  		release_sock(sk);
  		break;
  	}

  	case SIOCX25SFACILITIES: {
  		struct x25_facilities facilities;
  		rc = -EFAULT;
  		if (copy_from_user(&facilities, argp, sizeof(facilities)))
  			break;
  		rc = -EINVAL;
  		lock_sock(sk);
  		if (sk->sk_state != TCP_LISTEN &&
  		    sk->sk_state != TCP_CLOSE)
  			goto out_fac_release;
  		if (facilities.pacsize_in < X25_PS16 ||
  		    facilities.pacsize_in > X25_PS4096)
  			goto out_fac_release;
  		if (facilities.pacsize_out < X25_PS16 ||
  		    facilities.pacsize_out > X25_PS4096)
  			goto out_fac_release;
  		if (facilities.winsize_in < 1 ||
  		    facilities.winsize_in > 127)
  			goto out_fac_release;
  		if (facilities.throughput) {
  			int out = facilities.throughput & 0xf0;
  			int in  = facilities.throughput & 0x0f;
  			if (!out)
  				facilities.throughput |=
  					X25_DEFAULT_THROUGHPUT << 4;
  			else if (out < 0x30 || out > 0xD0)

  				goto out_fac_release;

  			if (!in)
  				facilities.throughput |=
  					X25_DEFAULT_THROUGHPUT;
  			else if (in < 0x03 || in > 0x0D)

  				goto out_fac_release;

  		}

  		if (facilities.reverse &&
  		    (facilities.reverse & 0x81) != 0x81)
  			goto out_fac_release;
  		x25->facilities = facilities;
  		rc = 0;
  out_fac_release:
  		release_sock(sk);
  		break;
  	}

  	case SIOCX25GDTEFACILITIES: {
  		lock_sock(sk);
  		rc = copy_to_user(argp, &x25->dte_facilities,
  				  sizeof(x25->dte_facilities));
  		release_sock(sk);
  		if (rc)

  			rc = -EFAULT;

  		break;
  	}

  	case SIOCX25SDTEFACILITIES: {
  		struct x25_dte_facilities dtefacs;
  		rc = -EFAULT;
  		if (copy_from_user(&dtefacs, argp, sizeof(dtefacs)))

  			break;

  		rc = -EINVAL;
  		lock_sock(sk);
  		if (sk->sk_state != TCP_LISTEN &&
  		    sk->sk_state != TCP_CLOSE)
  			goto out_dtefac_release;
  		if (dtefacs.calling_len > X25_MAX_AE_LEN)
  			goto out_dtefac_release;
  		if (dtefacs.calling_ae == NULL)
  			goto out_dtefac_release;
  		if (dtefacs.called_len > X25_MAX_AE_LEN)
  			goto out_dtefac_release;
  		if (dtefacs.called_ae == NULL)
  			goto out_dtefac_release;
  		x25->dte_facilities = dtefacs;
  		rc = 0;
  out_dtefac_release:
  		release_sock(sk);
  		break;
  	}

  	case SIOCX25GCALLUSERDATA: {
  		lock_sock(sk);
  		rc = copy_to_user(argp, &x25->calluserdata,
  				  sizeof(x25->calluserdata))
  			? -EFAULT : 0;
  		release_sock(sk);
  		break;
  	}

  	case SIOCX25SCALLUSERDATA: {
  		struct x25_calluserdata calluserdata;

  		rc = -EFAULT;
  		if (copy_from_user(&calluserdata, argp, sizeof(calluserdata)))

  			break;

  		rc = -EINVAL;
  		if (calluserdata.cudlength > X25_MAX_CUD_LEN)
  			break;
  		lock_sock(sk);
  		x25->calluserdata = calluserdata;
  		release_sock(sk);
  		rc = 0;
  		break;
  	}

  	case SIOCX25GCAUSEDIAG: {
  		lock_sock(sk);
  		rc = copy_to_user(argp, &x25->causediag, sizeof(x25->causediag))
  			? -EFAULT : 0;
  		release_sock(sk);
  		break;
  	}
  
  	case SIOCX25SCAUSEDIAG: {
  		struct x25_causediag causediag;
  		rc = -EFAULT;
  		if (copy_from_user(&causediag, argp, sizeof(causediag)))

  			break;

  		lock_sock(sk);
  		x25->causediag = causediag;
  		release_sock(sk);
  		rc = 0;
  		break;

  	}

  	case SIOCX25SCUDMATCHLEN: {
  		struct x25_subaddr sub_addr;
  		rc = -EINVAL;
  		lock_sock(sk);
  		if(sk->sk_state != TCP_CLOSE)
  			goto out_cud_release;
  		rc = -EFAULT;
  		if (copy_from_user(&sub_addr, argp,
  				   sizeof(sub_addr)))
  			goto out_cud_release;
  		rc = -EINVAL;
  		if (sub_addr.cudmatchlength > X25_MAX_CUD_LEN)
  			goto out_cud_release;
  		x25->cudmatchlength = sub_addr.cudmatchlength;
  		rc = 0;

  out_cud_release:

  		release_sock(sk);
  		break;
  	}

  	case SIOCX25CALLACCPTAPPRV: {
  		rc = -EINVAL;
  		lock_sock(sk);
  		if (sk->sk_state != TCP_CLOSE)

  			break;

  		clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);
  		release_sock(sk);
  		rc = 0;
  		break;
  	}

  	case SIOCX25SENDCALLACCPT:  {
  		rc = -EINVAL;
  		lock_sock(sk);
  		if (sk->sk_state != TCP_ESTABLISHED)

  			break;

  		/* must call accptapprv above */
  		if (test_bit(X25_ACCPT_APPRV_FLAG, &x25->flags))

  			break;

  		x25_write_internal(sk, X25_CALL_ACCEPTED);
  		x25->state = X25_STATE_3;
  		release_sock(sk);
  		rc = 0;
  		break;
  	}
  
  	default:
  		rc = -ENOIOCTLCMD;
  		break;

  	}
  
  	return rc;
  }

  static const struct net_proto_family x25_family_ops = {

  	.family =	AF_X25,
  	.create =	x25_create,
  	.owner	=	THIS_MODULE,
  };

  #ifdef CONFIG_COMPAT
  static int compat_x25_subscr_ioctl(unsigned int cmd,
  		struct compat_x25_subscrip_struct __user *x25_subscr32)
  {
  	struct compat_x25_subscrip_struct x25_subscr;
  	struct x25_neigh *nb;
  	struct net_device *dev;
  	int rc = -EINVAL;
  
  	rc = -EFAULT;
  	if (copy_from_user(&x25_subscr, x25_subscr32, sizeof(*x25_subscr32)))
  		goto out;
  
  	rc = -EINVAL;
  	dev = x25_dev_get(x25_subscr.device);
  	if (dev == NULL)
  		goto out;
  
  	nb = x25_get_neigh(dev);
  	if (nb == NULL)
  		goto out_dev_put;
  
  	dev_put(dev);
  
  	if (cmd == SIOCX25GSUBSCRIP) {

  		read_lock_bh(&x25_neigh_list_lock);

  		x25_subscr.extended = nb->extended;
  		x25_subscr.global_facil_mask = nb->global_facil_mask;

  		read_unlock_bh(&x25_neigh_list_lock);

  		rc = copy_to_user(x25_subscr32, &x25_subscr,
  				sizeof(*x25_subscr32)) ? -EFAULT : 0;
  	} else {
  		rc = -EINVAL;
  		if (x25_subscr.extended == 0 || x25_subscr.extended == 1) {
  			rc = 0;

  			write_lock_bh(&x25_neigh_list_lock);

  			nb->extended = x25_subscr.extended;
  			nb->global_facil_mask = x25_subscr.global_facil_mask;

  			write_unlock_bh(&x25_neigh_list_lock);

  		}
  	}
  	x25_neigh_put(nb);
  out:
  	return rc;
  out_dev_put:
  	dev_put(dev);
  	goto out;
  }
  
  static int compat_x25_ioctl(struct socket *sock, unsigned int cmd,
  				unsigned long arg)
  {
  	void __user *argp = compat_ptr(arg);
  	struct sock *sk = sock->sk;
  
  	int rc = -ENOIOCTLCMD;
  
  	switch(cmd) {
  	case TIOCOUTQ:
  	case TIOCINQ:
  		rc = x25_ioctl(sock, cmd, (unsigned long)argp);
  		break;
  	case SIOCGSTAMP:
  		rc = -EINVAL;
  		if (sk)
  			rc = compat_sock_get_timestamp(sk,
  					(struct timeval __user*)argp);
  		break;

  	case SIOCGSTAMPNS:
  		rc = -EINVAL;
  		if (sk)
  			rc = compat_sock_get_timestampns(sk,
  					(struct timespec __user*)argp);
  		break;

  	case SIOCGIFADDR:
  	case SIOCSIFADDR:
  	case SIOCGIFDSTADDR:
  	case SIOCSIFDSTADDR:
  	case SIOCGIFBRDADDR:
  	case SIOCSIFBRDADDR:
  	case SIOCGIFNETMASK:
  	case SIOCSIFNETMASK:
  	case SIOCGIFMETRIC:
  	case SIOCSIFMETRIC:
  		rc = -EINVAL;
  		break;
  	case SIOCADDRT:
  	case SIOCDELRT:
  		rc = -EPERM;
  		if (!capable(CAP_NET_ADMIN))
  			break;
  		rc = x25_route_ioctl(cmd, argp);
  		break;
  	case SIOCX25GSUBSCRIP:
  		rc = compat_x25_subscr_ioctl(cmd, argp);
  		break;
  	case SIOCX25SSUBSCRIP:
  		rc = -EPERM;
  		if (!capable(CAP_NET_ADMIN))
  			break;
  		rc = compat_x25_subscr_ioctl(cmd, argp);
  		break;
  	case SIOCX25GFACILITIES:
  	case SIOCX25SFACILITIES:

  	case SIOCX25GDTEFACILITIES:
  	case SIOCX25SDTEFACILITIES:

  	case SIOCX25GCALLUSERDATA:
  	case SIOCX25SCALLUSERDATA:
  	case SIOCX25GCAUSEDIAG:

  	case SIOCX25SCAUSEDIAG:

  	case SIOCX25SCUDMATCHLEN:
  	case SIOCX25CALLACCPTAPPRV:
  	case SIOCX25SENDCALLACCPT:
  		rc = x25_ioctl(sock, cmd, (unsigned long)argp);
  		break;
  	default:
  		rc = -ENOIOCTLCMD;
  		break;
  	}
  	return rc;
  }
  #endif

  static const struct proto_ops x25_proto_ops = {

  	.family =	AF_X25,
  	.owner =	THIS_MODULE,
  	.release =	x25_release,
  	.bind =		x25_bind,
  	.connect =	x25_connect,
  	.socketpair =	sock_no_socketpair,
  	.accept =	x25_accept,
  	.getname =	x25_getname,

  	.poll =		datagram_poll,

  	.ioctl =	x25_ioctl,

  #ifdef CONFIG_COMPAT
  	.compat_ioctl = compat_x25_ioctl,
  #endif

  	.listen =	x25_listen,
  	.shutdown =	sock_no_shutdown,
  	.setsockopt =	x25_setsockopt,
  	.getsockopt =	x25_getsockopt,
  	.sendmsg =	x25_sendmsg,
  	.recvmsg =	x25_recvmsg,
  	.mmap =		sock_no_mmap,
  	.sendpage =	sock_no_sendpage,
  };

  static struct packet_type x25_packet_type __read_mostly = {

  	.type =	cpu_to_be16(ETH_P_X25),

  	.func =	x25_lapb_receive_frame,
  };
  
  static struct notifier_block x25_dev_notifier = {
  	.notifier_call = x25_device_event,
  };
  
  void x25_kill_by_neigh(struct x25_neigh *nb)
  {
  	struct sock *s;
  	struct hlist_node *node;
  
  	write_lock_bh(&x25_list_lock);
  
  	sk_for_each(s, node, &x25_list)
  		if (x25_sk(s)->neighbour == nb)
  			x25_disconnect(s, ENETUNREACH, 0, 0);
  
  	write_unlock_bh(&x25_list_lock);

  
  	/* Remove any related forwards */
  	x25_clear_forward_by_dev(nb->dev);

  }
  
  static int __init x25_init(void)
  {
  	int rc = proto_register(&x25_proto, 0);
  
  	if (rc != 0)
  		goto out;

  	rc = sock_register(&x25_family_ops);
  	if (rc != 0)
  		goto out_proto;

  
  	dev_add_pack(&x25_packet_type);

  	rc = register_netdevice_notifier(&x25_dev_notifier);
  	if (rc != 0)
  		goto out_sock;

  	printk(KERN_INFO "X.25 for Linux Version 0.2
  ");

  	x25_register_sysctl();

  	rc = x25_proc_init();
  	if (rc != 0)
  		goto out_dev;

  out:
  	return rc;

  out_dev:
  	unregister_netdevice_notifier(&x25_dev_notifier);
  out_sock:
  	sock_unregister(AF_X25);
  out_proto:
  	proto_unregister(&x25_proto);
  	goto out;

  }
  module_init(x25_init);
  
  static void __exit x25_exit(void)
  {
  	x25_proc_exit();
  	x25_link_free();
  	x25_route_free();

  	x25_unregister_sysctl();

  
  	unregister_netdevice_notifier(&x25_dev_notifier);
  
  	dev_remove_pack(&x25_packet_type);
  
  	sock_unregister(AF_X25);
  	proto_unregister(&x25_proto);
  }
  module_exit(x25_exit);
  
  MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
  MODULE_DESCRIPTION("The X.25 Packet Layer network layer protocol");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_NETPROTO(PF_X25);