text: /*
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   * Copyright Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
   * Copyright Darryl Miles G7LED (dlm@g7led.demon.co.uk)
   */
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/capability.h>
  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/socket.h>
  #include <linux/in.h>
  #include <linux/slab.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/timer.h>
  #include <linux/string.h>
  #include <linux/sockios.h>
  #include <linux/net.h>
  #include <linux/stat.h>
  #include <net/ax25.h>
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <linux/if_arp.h>
  #include <linux/skbuff.h>
  #include <net/net_namespace.h>
  #include <net/sock.h>
  #include <asm/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 <net/netrom.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <net/ip.h>
  #include <net/tcp_states.h>
  #include <net/arp.h>
  #include <linux/init.h>
  
  static int nr_ndevs = 4;
  
  int sysctl_netrom_default_path_quality            = NR_DEFAULT_QUAL;
  int sysctl_netrom_obsolescence_count_initialiser  = NR_DEFAULT_OBS;
  int sysctl_netrom_network_ttl_initialiser         = NR_DEFAULT_TTL;
  int sysctl_netrom_transport_timeout               = NR_DEFAULT_T1;
  int sysctl_netrom_transport_maximum_tries         = NR_DEFAULT_N2;
  int sysctl_netrom_transport_acknowledge_delay     = NR_DEFAULT_T2;
  int sysctl_netrom_transport_busy_delay            = NR_DEFAULT_T4;
  int sysctl_netrom_transport_requested_window_size = NR_DEFAULT_WINDOW;
  int sysctl_netrom_transport_no_activity_timeout   = NR_DEFAULT_IDLE;
  int sysctl_netrom_routing_control                 = NR_DEFAULT_ROUTING;
  int sysctl_netrom_link_fails_count                = NR_DEFAULT_FAILS;
  int sysctl_netrom_reset_circuit                   = NR_DEFAULT_RESET;
  
  static unsigned short circuit = 0x101;
  
  static HLIST_HEAD(nr_list);
  static DEFINE_SPINLOCK(nr_list_lock);
  
  static const struct proto_ops nr_proto_ops;
  
  /*
   * NETROM network devices are virtual network devices encapsulating NETROM
   * frames into AX.25 which will be sent through an AX.25 device, so form a
   * special "super class" of normal net devices; split their locks off into a
   * separate class since they always nest.
   */
  static struct lock_class_key nr_netdev_xmit_lock_key;
  static struct lock_class_key nr_netdev_addr_lock_key;
  
  static void nr_set_lockdep_one(struct net_device *dev,
  			       struct netdev_queue *txq,
  			       void *_unused)
  {
  	lockdep_set_class(&txq->_xmit_lock, &nr_netdev_xmit_lock_key);
  }
  
  static void nr_set_lockdep_key(struct net_device *dev)
  {
  	lockdep_set_class(&dev->addr_list_lock, &nr_netdev_addr_lock_key);
  	netdev_for_each_tx_queue(dev, nr_set_lockdep_one, NULL);
  }
  
  /*
   *	Socket removal during an interrupt is now safe.
   */
  static void nr_remove_socket(struct sock *sk)
  {
  	spin_lock_bh(&nr_list_lock);
  	sk_del_node_init(sk);
  	spin_unlock_bh(&nr_list_lock);
  }
  
  /*
   *	Kill all bound sockets on a dropped device.
   */
  static void nr_kill_by_device(struct net_device *dev)
  {
  	struct sock *s;
  
  	spin_lock_bh(&nr_list_lock);
  	sk_for_each(s, &nr_list)
  		if (nr_sk(s)->device == dev)
  			nr_disconnect(s, ENETUNREACH);
  	spin_unlock_bh(&nr_list_lock);
  }
  
  /*
   *	Handle device status changes.
   */
  static int nr_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;
  
  	if (event != NETDEV_DOWN)
  		return NOTIFY_DONE;
  
  	nr_kill_by_device(dev);
  	nr_rt_device_down(dev);
  
  	return NOTIFY_DONE;
  }
  
  /*
   *	Add a socket to the bound sockets list.
   */
  static void nr_insert_socket(struct sock *sk)
  {
  	spin_lock_bh(&nr_list_lock);
  	sk_add_node(sk, &nr_list);
  	spin_unlock_bh(&nr_list_lock);
  }
  
  /*
   *	Find a socket that wants to accept the Connect Request we just
   *	received.
   */
  static struct sock *nr_find_listener(ax25_address *addr)
  {
  	struct sock *s;
  
  	spin_lock_bh(&nr_list_lock);
  	sk_for_each(s, &nr_list)
  		if (!ax25cmp(&nr_sk(s)->source_addr, addr) &&
  		    s->sk_state == TCP_LISTEN) {
  			bh_lock_sock(s);
  			goto found;
  		}
  	s = NULL;
  found:
  	spin_unlock_bh(&nr_list_lock);
  	return s;
  }
  
  /*
   *	Find a connected NET/ROM socket given my circuit IDs.
   */
  static struct sock *nr_find_socket(unsigned char index, unsigned char id)
  {
  	struct sock *s;
  
  	spin_lock_bh(&nr_list_lock);
  	sk_for_each(s, &nr_list) {
  		struct nr_sock *nr = nr_sk(s);
  
  		if (nr->my_index == index && nr->my_id == id) {
  			bh_lock_sock(s);
  			goto found;
  		}
  	}
  	s = NULL;
  found:
  	spin_unlock_bh(&nr_list_lock);
  	return s;
  }
  
  /*
   *	Find a connected NET/ROM socket given their circuit IDs.
   */
  static struct sock *nr_find_peer(unsigned char index, unsigned char id,
  	ax25_address *dest)
  {
  	struct sock *s;
  
  	spin_lock_bh(&nr_list_lock);
  	sk_for_each(s, &nr_list) {
  		struct nr_sock *nr = nr_sk(s);
  
  		if (nr->your_index == index && nr->your_id == id &&
  		    !ax25cmp(&nr->dest_addr, dest)) {
  			bh_lock_sock(s);
  			goto found;
  		}
  	}
  	s = NULL;
  found:
  	spin_unlock_bh(&nr_list_lock);
  	return s;
  }
  
  /*
   *	Find next free circuit ID.
   */
  static unsigned short nr_find_next_circuit(void)
  {
  	unsigned short id = circuit;
  	unsigned char i, j;
  	struct sock *sk;
  
  	for (;;) {
  		i = id / 256;
  		j = id % 256;
  
  		if (i != 0 && j != 0) {
  			if ((sk=nr_find_socket(i, j)) == NULL)
  				break;
  			bh_unlock_sock(sk);
  		}
  
  		id++;
  	}
  
  	return id;
  }
  
  /*
   *	Deferred destroy.
   */
  void nr_destroy_socket(struct sock *);
  
  /*
   *	Handler for deferred kills.
   */
  static void nr_destroy_timer(unsigned long data)
  {
  	struct sock *sk=(struct sock *)data;
  	bh_lock_sock(sk);
  	sock_hold(sk);
  	nr_destroy_socket(sk);
  	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 nr_destroy_socket(struct sock *sk)
  {
  	struct sk_buff *skb;
  
  	nr_remove_socket(sk);
  
  	nr_stop_heartbeat(sk);
  	nr_stop_t1timer(sk);
  	nr_stop_t2timer(sk);
  	nr_stop_t4timer(sk);
  	nr_stop_idletimer(sk);
  
  	nr_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 */
  			sock_set_flag(skb->sk, SOCK_DEAD);
  			nr_start_heartbeat(skb->sk);
  			nr_sk(skb->sk)->state = NR_STATE_0;
  		}
  
  		kfree_skb(skb);
  	}
  
  	if (sk_has_allocations(sk)) {
  		/* Defer: outstanding buffers */
  		sk->sk_timer.function = nr_destroy_timer;
  		sk->sk_timer.expires  = jiffies + 2 * HZ;
  		add_timer(&sk->sk_timer);
  	} else
  		sock_put(sk);
  }
  
  /*
   *	Handling for system calls applied via the various interfaces to a
   *	NET/ROM socket object.
   */
  
  static int nr_setsockopt(struct socket *sock, int level, int optname,
  	char __user *optval, unsigned int optlen)
  {
  	struct sock *sk = sock->sk;
  	struct nr_sock *nr = nr_sk(sk);
  	unsigned long opt;
  
  	if (level != SOL_NETROM)
  		return -ENOPROTOOPT;
  
  	if (optlen < sizeof(unsigned int))
  		return -EINVAL;
  
  	if (get_user(opt, (unsigned int __user *)optval))
  		return -EFAULT;
  
  	switch (optname) {
  	case NETROM_T1:
  		if (opt < 1 || opt > ULONG_MAX / HZ)
  			return -EINVAL;
  		nr->t1 = opt * HZ;
  		return 0;
  
  	case NETROM_T2:
  		if (opt < 1 || opt > ULONG_MAX / HZ)
  			return -EINVAL;
  		nr->t2 = opt * HZ;
  		return 0;
  
  	case NETROM_N2:
  		if (opt < 1 || opt > 31)
  			return -EINVAL;
  		nr->n2 = opt;
  		return 0;
  
  	case NETROM_T4:
  		if (opt < 1 || opt > ULONG_MAX / HZ)
  			return -EINVAL;
  		nr->t4 = opt * HZ;
  		return 0;
  
  	case NETROM_IDLE:
  		if (opt > ULONG_MAX / (60 * HZ))
  			return -EINVAL;
  		nr->idle = opt * 60 * HZ;
  		return 0;
  
  	default:
  		return -ENOPROTOOPT;
  	}
  }
  
  static int nr_getsockopt(struct socket *sock, int level, int optname,
  	char __user *optval, int __user *optlen)
  {
  	struct sock *sk = sock->sk;
  	struct nr_sock *nr = nr_sk(sk);
  	int val = 0;
  	int len;
  
  	if (level != SOL_NETROM)
  		return -ENOPROTOOPT;
  
  	if (get_user(len, optlen))
  		return -EFAULT;
  
  	if (len < 0)
  		return -EINVAL;
  
  	switch (optname) {
  	case NETROM_T1:
  		val = nr->t1 / HZ;
  		break;
  
  	case NETROM_T2:
  		val = nr->t2 / HZ;
  		break;
  
  	case NETROM_N2:
  		val = nr->n2;
  		break;
  
  	case NETROM_T4:
  		val = nr->t4 / HZ;
  		break;
  
  	case NETROM_IDLE:
  		val = nr->idle / (60 * HZ);
  		break;
  
  	default:
  		return -ENOPROTOOPT;
  	}
  
  	len = min_t(unsigned int, len, sizeof(int));
  
  	if (put_user(len, optlen))
  		return -EFAULT;
  
  	return copy_to_user(optval, &val, len) ? -EFAULT : 0;
  }
  
  static int nr_listen(struct socket *sock, int backlog)
  {
  	struct sock *sk = sock->sk;
  
  	lock_sock(sk);
  	if (sk->sk_state != TCP_LISTEN) {
  		memset(&nr_sk(sk)->user_addr, 0, AX25_ADDR_LEN);
  		sk->sk_max_ack_backlog = backlog;
  		sk->sk_state           = TCP_LISTEN;
  		release_sock(sk);
  		return 0;
  	}
  	release_sock(sk);
  
  	return -EOPNOTSUPP;
  }
  
  static struct proto nr_proto = {
  	.name	  = "NETROM",
  	.owner	  = THIS_MODULE,
  	.obj_size = sizeof(struct nr_sock),
  };
  
  static int nr_create(struct net *net, struct socket *sock, int protocol,
  		     int kern)
  {
  	struct sock *sk;
  	struct nr_sock *nr;
  
  	if (!net_eq(net, &init_net))
  		return -EAFNOSUPPORT;
  
  	if (sock->type != SOCK_SEQPACKET || protocol != 0)
  		return -ESOCKTNOSUPPORT;
  
  	sk = sk_alloc(net, PF_NETROM, GFP_ATOMIC, &nr_proto);
  	if (sk  == NULL)
  		return -ENOMEM;
  
  	nr = nr_sk(sk);
  
  	sock_init_data(sock, sk);
  
  	sock->ops    = &nr_proto_ops;
  	sk->sk_protocol = protocol;
  
  	skb_queue_head_init(&nr->ack_queue);
  	skb_queue_head_init(&nr->reseq_queue);
  	skb_queue_head_init(&nr->frag_queue);
  
  	nr_init_timers(sk);
  
  	nr->t1     =
  		msecs_to_jiffies(sysctl_netrom_transport_timeout);
  	nr->t2     =
  		msecs_to_jiffies(sysctl_netrom_transport_acknowledge_delay);
  	nr->n2     =
  		msecs_to_jiffies(sysctl_netrom_transport_maximum_tries);
  	nr->t4     =
  		msecs_to_jiffies(sysctl_netrom_transport_busy_delay);
  	nr->idle   =
  		msecs_to_jiffies(sysctl_netrom_transport_no_activity_timeout);
  	nr->window = sysctl_netrom_transport_requested_window_size;
  
  	nr->bpqext = 1;
  	nr->state  = NR_STATE_0;
  
  	return 0;
  }
  
  static struct sock *nr_make_new(struct sock *osk)
  {
  	struct sock *sk;
  	struct nr_sock *nr, *onr;
  
  	if (osk->sk_type != SOCK_SEQPACKET)
  		return NULL;
  
  	sk = sk_alloc(sock_net(osk), PF_NETROM, GFP_ATOMIC, osk->sk_prot);
  	if (sk == NULL)
  		return NULL;
  
  	nr = nr_sk(sk);
  
  	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);
  
  	skb_queue_head_init(&nr->ack_queue);
  	skb_queue_head_init(&nr->reseq_queue);
  	skb_queue_head_init(&nr->frag_queue);
  
  	nr_init_timers(sk);
  
  	onr = nr_sk(osk);
  
  	nr->t1      = onr->t1;
  	nr->t2      = onr->t2;
  	nr->n2      = onr->n2;
  	nr->t4      = onr->t4;
  	nr->idle    = onr->idle;
  	nr->window  = onr->window;
  
  	nr->device  = onr->device;
  	nr->bpqext  = onr->bpqext;
  
  	return sk;
  }
  
  static int nr_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  	struct nr_sock *nr;
  
  	if (sk == NULL) return 0;
  
  	sock_hold(sk);
  	sock_orphan(sk);
  	lock_sock(sk);
  	nr = nr_sk(sk);
  
  	switch (nr->state) {
  	case NR_STATE_0:
  	case NR_STATE_1:
  	case NR_STATE_2:
  		nr_disconnect(sk, 0);
  		nr_destroy_socket(sk);
  		break;
  
  	case NR_STATE_3:
  		nr_clear_queues(sk);
  		nr->n2count = 0;
  		nr_write_internal(sk, NR_DISCREQ);
  		nr_start_t1timer(sk);
  		nr_stop_t2timer(sk);
  		nr_stop_t4timer(sk);
  		nr_stop_idletimer(sk);
  		nr->state    = NR_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;
  	}
  
  	sock->sk   = NULL;
  	release_sock(sk);
  	sock_put(sk);
  
  	return 0;
  }
  
  static int nr_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
  {
  	struct sock *sk = sock->sk;
  	struct nr_sock *nr = nr_sk(sk);
  	struct full_sockaddr_ax25 *addr = (struct full_sockaddr_ax25 *)uaddr;
  	struct net_device *dev;
  	ax25_uid_assoc *user;
  	ax25_address *source;
  
  	lock_sock(sk);
  	if (!sock_flag(sk, SOCK_ZAPPED)) {
  		release_sock(sk);
  		return -EINVAL;
  	}
  	if (addr_len < sizeof(struct sockaddr_ax25) || addr_len > sizeof(struct full_sockaddr_ax25)) {
  		release_sock(sk);
  		return -EINVAL;
  	}
  	if (addr_len < (addr->fsa_ax25.sax25_ndigis * sizeof(ax25_address) + sizeof(struct sockaddr_ax25))) {
  		release_sock(sk);
  		return -EINVAL;
  	}
  	if (addr->fsa_ax25.sax25_family != AF_NETROM) {
  		release_sock(sk);
  		return -EINVAL;
  	}
  	if ((dev = nr_dev_get(&addr->fsa_ax25.sax25_call)) == NULL) {
  		release_sock(sk);
  		return -EADDRNOTAVAIL;
  	}
  
  	/*
  	 * Only the super user can set an arbitrary user callsign.
  	 */
  	if (addr->fsa_ax25.sax25_ndigis == 1) {
  		if (!capable(CAP_NET_BIND_SERVICE)) {
  			dev_put(dev);
  			release_sock(sk);
  			return -EPERM;
  		}
  		nr->user_addr   = addr->fsa_digipeater[0];
  		nr->source_addr = addr->fsa_ax25.sax25_call;
  	} else {
  		source = &addr->fsa_ax25.sax25_call;
  
  		user = ax25_findbyuid(current_euid());
  		if (user) {
  			nr->user_addr   = user->call;
  			ax25_uid_put(user);
  		} else {
  			if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
  				release_sock(sk);
  				dev_put(dev);
  				return -EPERM;
  			}
  			nr->user_addr   = *source;
  		}
  
  		nr->source_addr = *source;
  	}
  
  	nr->device = dev;
  	nr_insert_socket(sk);
  
  	sock_reset_flag(sk, SOCK_ZAPPED);
  	dev_put(dev);
  	release_sock(sk);
  
  	return 0;
  }
  
  static int nr_connect(struct socket *sock, struct sockaddr *uaddr,
  	int addr_len, int flags)
  {
  	struct sock *sk = sock->sk;
  	struct nr_sock *nr = nr_sk(sk);
  	struct sockaddr_ax25 *addr = (struct sockaddr_ax25 *)uaddr;
  	ax25_address *source = NULL;
  	ax25_uid_assoc *user;
  	struct net_device *dev;
  	int err = 0;
  
  	lock_sock(sk);
  	if (sk->sk_state == TCP_ESTABLISHED && sock->state == SS_CONNECTING) {
  		sock->state = SS_CONNECTED;
  		goto out_release;	/* Connect completed during a ERESTARTSYS event */
  	}
  
  	if (sk->sk_state == TCP_CLOSE && sock->state == SS_CONNECTING) {
  		sock->state = SS_UNCONNECTED;
  		err = -ECONNREFUSED;
  		goto out_release;
  	}
  
  	if (sk->sk_state == TCP_ESTABLISHED) {
  		err = -EISCONN;	/* No reconnect on a seqpacket socket */
  		goto out_release;
  	}
  
  	sk->sk_state   = TCP_CLOSE;
  	sock->state = SS_UNCONNECTED;
  
  	if (addr_len != sizeof(struct sockaddr_ax25) && addr_len != sizeof(struct full_sockaddr_ax25)) {
  		err = -EINVAL;
  		goto out_release;
  	}
  	if (addr->sax25_family != AF_NETROM) {
  		err = -EINVAL;
  		goto out_release;
  	}
  	if (sock_flag(sk, SOCK_ZAPPED)) {	/* Must bind first - autobinding in this may or may not work */
  		sock_reset_flag(sk, SOCK_ZAPPED);
  
  		if ((dev = nr_dev_first()) == NULL) {
  			err = -ENETUNREACH;
  			goto out_release;
  		}
  		source = (ax25_address *)dev->dev_addr;
  
  		user = ax25_findbyuid(current_euid());
  		if (user) {
  			nr->user_addr   = user->call;
  			ax25_uid_put(user);
  		} else {
  			if (ax25_uid_policy && !capable(CAP_NET_ADMIN)) {
  				dev_put(dev);
  				err = -EPERM;
  				goto out_release;
  			}
  			nr->user_addr   = *source;
  		}
  
  		nr->source_addr = *source;
  		nr->device      = dev;
  
  		dev_put(dev);
  		nr_insert_socket(sk);		/* Finish the bind */
  	}
  
  	nr->dest_addr = addr->sax25_call;
  
  	release_sock(sk);
  	circuit = nr_find_next_circuit();
  	lock_sock(sk);
  
  	nr->my_index = circuit / 256;
  	nr->my_id    = circuit % 256;
  
  	circuit++;
  
  	/* Move to connecting socket, start sending Connect Requests */
  	sock->state  = SS_CONNECTING;
  	sk->sk_state = TCP_SYN_SENT;
  
  	nr_establish_data_link(sk);
  
  	nr->state = NR_STATE_1;
  
  	nr_start_heartbeat(sk);
  
  	/* Now the loop */
  	if (sk->sk_state != TCP_ESTABLISHED && (flags & O_NONBLOCK)) {
  		err = -EINPROGRESS;
  		goto out_release;
  	}
  
  	/*
  	 * A Connect Ack with Choke or timeout or failed routing will go to
  	 * closed.
  	 */
  	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) {
  		sock->state = SS_UNCONNECTED;
  		err = sock_error(sk);	/* Always set at this point */
  		goto out_release;
  	}
  
  	sock->state = SS_CONNECTED;
  
  out_release:
  	release_sock(sk);
  
  	return err;
  }
  
  static int nr_accept(struct socket *sock, struct socket *newsock, int flags)
  {
  	struct sk_buff *skb;
  	struct sock *newsk;
  	DEFINE_WAIT(wait);
  	struct sock *sk;
  	int err = 0;
  
  	if ((sk = sock->sk) == NULL)
  		return -EINVAL;
  
  	lock_sock(sk);
  	if (sk->sk_type != SOCK_SEQPACKET) {
  		err = -EOPNOTSUPP;
  		goto out_release;
  	}
  
  	if (sk->sk_state != TCP_LISTEN) {
  		err = -EINVAL;
  		goto out_release;
  	}
  
  	/*
  	 *	The write 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_release;
  
  	newsk = skb->sk;
  	sock_graft(newsk, newsock);
  
  	/* Now attach up the new socket */
  	kfree_skb(skb);
  	sk_acceptq_removed(sk);
  
  out_release:
  	release_sock(sk);
  
  	return err;
  }
  
  static int nr_getname(struct socket *sock, struct sockaddr *uaddr,
  	int *uaddr_len, int peer)
  {
  	struct full_sockaddr_ax25 *sax = (struct full_sockaddr_ax25 *)uaddr;
  	struct sock *sk = sock->sk;
  	struct nr_sock *nr = nr_sk(sk);
  
  	memset(&sax->fsa_ax25, 0, sizeof(struct sockaddr_ax25));
  
  	lock_sock(sk);
  	if (peer != 0) {
  		if (sk->sk_state != TCP_ESTABLISHED) {
  			release_sock(sk);
  			return -ENOTCONN;
  		}
  		sax->fsa_ax25.sax25_family = AF_NETROM;
  		sax->fsa_ax25.sax25_ndigis = 1;
  		sax->fsa_ax25.sax25_call   = nr->user_addr;
  		memset(sax->fsa_digipeater, 0, sizeof(sax->fsa_digipeater));
  		sax->fsa_digipeater[0]     = nr->dest_addr;
  		*uaddr_len = sizeof(struct full_sockaddr_ax25);
  	} else {
  		sax->fsa_ax25.sax25_family = AF_NETROM;
  		sax->fsa_ax25.sax25_ndigis = 0;
  		sax->fsa_ax25.sax25_call   = nr->source_addr;
  		*uaddr_len = sizeof(struct sockaddr_ax25);
  	}
  	release_sock(sk);
  
  	return 0;
  }
  
  int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
  {
  	struct sock *sk;
  	struct sock *make;
  	struct nr_sock *nr_make;
  	ax25_address *src, *dest, *user;
  	unsigned short circuit_index, circuit_id;
  	unsigned short peer_circuit_index, peer_circuit_id;
  	unsigned short frametype, flags, window, timeout;
  	int ret;
  
  	skb->sk = NULL;		/* Initially we don't know who it's for */
  
  	/*
  	 *	skb->data points to the netrom frame start
  	 */
  
  	src  = (ax25_address *)(skb->data + 0);
  	dest = (ax25_address *)(skb->data + 7);
  
  	circuit_index      = skb->data[15];
  	circuit_id         = skb->data[16];
  	peer_circuit_index = skb->data[17];
  	peer_circuit_id    = skb->data[18];
  	frametype          = skb->data[19] & 0x0F;
  	flags              = skb->data[19] & 0xF0;
  
  	/*
  	 * Check for an incoming IP over NET/ROM frame.
  	 */
  	if (frametype == NR_PROTOEXT &&
  	    circuit_index == NR_PROTO_IP && circuit_id == NR_PROTO_IP) {
  		skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
  		skb_reset_transport_header(skb);
  
  		return nr_rx_ip(skb, dev);
  	}
  
  	/*
  	 * Find an existing socket connection, based on circuit ID, if it's
  	 * a Connect Request base it on their circuit ID.
  	 *
  	 * Circuit ID 0/0 is not valid but it could still be a "reset" for a
  	 * circuit that no longer exists at the other end ...
  	 */
  
  	sk = NULL;
  
  	if (circuit_index == 0 && circuit_id == 0) {
  		if (frametype == NR_CONNACK && flags == NR_CHOKE_FLAG)
  			sk = nr_find_peer(peer_circuit_index, peer_circuit_id, src);
  	} else {
  		if (frametype == NR_CONNREQ)
  			sk = nr_find_peer(circuit_index, circuit_id, src);
  		else
  			sk = nr_find_socket(circuit_index, circuit_id);
  	}
  
  	if (sk != NULL) {
  		skb_reset_transport_header(skb);
  
  		if (frametype == NR_CONNACK && skb->len == 22)
  			nr_sk(sk)->bpqext = 1;
  		else
  			nr_sk(sk)->bpqext = 0;
  
  		ret = nr_process_rx_frame(sk, skb);
  		bh_unlock_sock(sk);
  		return ret;
  	}
  
  	/*
  	 * Now it should be a CONNREQ.
  	 */
  	if (frametype != NR_CONNREQ) {
  		/*
  		 * Here it would be nice to be able to send a reset but
  		 * NET/ROM doesn't have one.  We've tried to extend the protocol
  		 * by sending NR_CONNACK | NR_CHOKE_FLAGS replies but that
  		 * apparently kills BPQ boxes... :-(
  		 * So now we try to follow the established behaviour of
  		 * G8PZT's Xrouter which is sending packets with command type 7
  		 * as an extension of the protocol.
  		 */
  		if (sysctl_netrom_reset_circuit &&
  		    (frametype != NR_RESET || flags != 0))
  			nr_transmit_reset(skb, 1);
  
  		return 0;
  	}
  
  	sk = nr_find_listener(dest);
  
  	user = (ax25_address *)(skb->data + 21);
  
  	if (sk == NULL || sk_acceptq_is_full(sk) ||
  	    (make = nr_make_new(sk)) == NULL) {
  		nr_transmit_refusal(skb, 0);
  		if (sk)
  			bh_unlock_sock(sk);
  		return 0;
  	}
  
  	window = skb->data[20];
  
  	skb->sk             = make;
  	make->sk_state	    = TCP_ESTABLISHED;
  
  	/* Fill in his circuit details */
  	nr_make = nr_sk(make);
  	nr_make->source_addr = *dest;
  	nr_make->dest_addr   = *src;
  	nr_make->user_addr   = *user;
  
  	nr_make->your_index  = circuit_index;
  	nr_make->your_id     = circuit_id;
  
  	bh_unlock_sock(sk);
  	circuit = nr_find_next_circuit();
  	bh_lock_sock(sk);
  
  	nr_make->my_index    = circuit / 256;
  	nr_make->my_id       = circuit % 256;
  
  	circuit++;
  
  	/* Window negotiation */
  	if (window < nr_make->window)
  		nr_make->window = window;
  
  	/* L4 timeout negotiation */
  	if (skb->len == 37) {
  		timeout = skb->data[36] * 256 + skb->data[35];
  		if (timeout * HZ < nr_make->t1)
  			nr_make->t1 = timeout * HZ;
  		nr_make->bpqext = 1;
  	} else {
  		nr_make->bpqext = 0;
  	}
  
  	nr_write_internal(make, NR_CONNACK);
  
  	nr_make->condition = 0x00;
  	nr_make->vs        = 0;
  	nr_make->va        = 0;
  	nr_make->vr        = 0;
  	nr_make->vl        = 0;
  	nr_make->state     = NR_STATE_3;
  	sk_acceptq_added(sk);
  	skb_queue_head(&sk->sk_receive_queue, skb);
  
  	if (!sock_flag(sk, SOCK_DEAD))
  		sk->sk_data_ready(sk, skb->len);
  
  	bh_unlock_sock(sk);
  
  	nr_insert_socket(make);
  
  	nr_start_heartbeat(make);
  	nr_start_idletimer(make);
  
  	return 1;
  }
  
  static int nr_sendmsg(struct kiocb *iocb, struct socket *sock,
  		      struct msghdr *msg, size_t len)
  {
  	struct sock *sk = sock->sk;
  	struct nr_sock *nr = nr_sk(sk);
  	DECLARE_SOCKADDR(struct sockaddr_ax25 *, usax, msg->msg_name);
  	int err;
  	struct sockaddr_ax25 sax;
  	struct sk_buff *skb;
  	unsigned char *asmptr;
  	int size;
  
  	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_CMSG_COMPAT))
  		return -EINVAL;
  
  	lock_sock(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 (nr->device == NULL) {
  		err = -ENETUNREACH;
  		goto out;
  	}
  
  	if (usax) {
  		if (msg->msg_namelen < sizeof(sax)) {
  			err = -EINVAL;
  			goto out;
  		}
  		sax = *usax;
  		if (ax25cmp(&nr->dest_addr, &sax.sax25_call) != 0) {
  			err = -EISCONN;
  			goto out;
  		}
  		if (sax.sax25_family != AF_NETROM) {
  			err = -EINVAL;
  			goto out;
  		}
  	} else {
  		if (sk->sk_state != TCP_ESTABLISHED) {
  			err = -ENOTCONN;
  			goto out;
  		}
  		sax.sax25_family = AF_NETROM;
  		sax.sax25_call   = nr->dest_addr;
  	}
  
  	/* Build a packet - the conventional user limit is 236 bytes. We can
  	   do ludicrously large NetROM frames but must not overflow */
  	if (len > 65536) {
  		err = -EMSGSIZE;
  		goto out;
  	}
  
  	size = len + NR_NETWORK_LEN + NR_TRANSPORT_LEN;
  
  	if ((skb = sock_alloc_send_skb(sk, size, msg->msg_flags & MSG_DONTWAIT, &err)) == NULL)
  		goto out;
  
  	skb_reserve(skb, size - len);
  	skb_reset_transport_header(skb);
  
  	/*
  	 *	Push down the NET/ROM header
  	 */
  
  	asmptr = skb_push(skb, NR_TRANSPORT_LEN);
  
  	/* Build a NET/ROM Transport header */
  
  	*asmptr++ = nr->your_index;
  	*asmptr++ = nr->your_id;
  	*asmptr++ = 0;		/* To be filled in later */
  	*asmptr++ = 0;		/*      Ditto            */
  	*asmptr++ = NR_INFO;
  
  	/*
  	 *	Put the data on the end
  	 */
  	skb_put(skb, len);
  
  	/* User data follows immediately after the NET/ROM transport header */
  	if (memcpy_fromiovec(skb_transport_header(skb), msg->msg_iov, len)) {
  		kfree_skb(skb);
  		err = -EFAULT;
  		goto out;
  	}
  
  	if (sk->sk_state != TCP_ESTABLISHED) {
  		kfree_skb(skb);
  		err = -ENOTCONN;
  		goto out;
  	}
  
  	nr_output(sk, skb);	/* Shove it onto the queue */
  
  	err = len;
  out:
  	release_sock(sk);
  	return err;
  }
  
  static int nr_recvmsg(struct kiocb *iocb, struct socket *sock,
  		      struct msghdr *msg, size_t size, int flags)
  {
  	struct sock *sk = sock->sk;
  	DECLARE_SOCKADDR(struct sockaddr_ax25 *, sax, msg->msg_name);
  	size_t copied;
  	struct sk_buff *skb;
  	int er;
  
  	/*
  	 * This works for seqpacket too. The receiver has ordered the queue for
  	 * us! We do one quick check first though
  	 */
  
  	lock_sock(sk);
  	if (sk->sk_state != TCP_ESTABLISHED) {
  		release_sock(sk);
  		return -ENOTCONN;
  	}
  
  	/* Now we can treat all alike */
  	if ((skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &er)) == NULL) {
  		release_sock(sk);
  		return er;
  	}
  
  	skb_reset_transport_header(skb);
  	copied     = skb->len;
  
  	if (copied > size) {
  		copied = size;
  		msg->msg_flags |= MSG_TRUNC;
  	}
  
  	er = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
  	if (er < 0) {
  		skb_free_datagram(sk, skb);
  		release_sock(sk);
  		return er;
  	}
  
  	if (sax != NULL) {
  		memset(sax, 0, sizeof(*sax));
  		sax->sax25_family = AF_NETROM;
  		skb_copy_from_linear_data_offset(skb, 7, sax->sax25_call.ax25_call,
  			      AX25_ADDR_LEN);
  		msg->msg_namelen = sizeof(*sax);
  	}
  
  	skb_free_datagram(sk, skb);
  
  	release_sock(sk);
  	return copied;
  }
  
  
  static int nr_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
  {
  	struct sock *sk = sock->sk;
  	void __user *argp = (void __user *)arg;
  	int ret;
  
  	switch (cmd) {
  	case TIOCOUTQ: {
  		long amount;
  
  		lock_sock(sk);
  		amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
  		if (amount < 0)
  			amount = 0;
  		release_sock(sk);
  		return put_user(amount, (int __user *)argp);
  	}
  
  	case TIOCINQ: {
  		struct sk_buff *skb;
  		long amount = 0L;
  
  		lock_sock(sk);
  		/* 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;
  		release_sock(sk);
  		return put_user(amount, (int __user *)argp);
  	}
  
  	case SIOCGSTAMP:
  		lock_sock(sk);
  		ret = sock_get_timestamp(sk, argp);
  		release_sock(sk);
  		return ret;
  
  	case SIOCGSTAMPNS:
  		lock_sock(sk);
  		ret = sock_get_timestampns(sk, argp);
  		release_sock(sk);
  		return ret;
  
  	case SIOCGIFADDR:
  	case SIOCSIFADDR:
  	case SIOCGIFDSTADDR:
  	case SIOCSIFDSTADDR:
  	case SIOCGIFBRDADDR:
  	case SIOCSIFBRDADDR:
  	case SIOCGIFNETMASK:
  	case SIOCSIFNETMASK:
  	case SIOCGIFMETRIC:
  	case SIOCSIFMETRIC:
  		return -EINVAL;
  
  	case SIOCADDRT:
  	case SIOCDELRT:
  	case SIOCNRDECOBS:
  		if (!capable(CAP_NET_ADMIN))
  			return -EPERM;
  		return nr_rt_ioctl(cmd, argp);
  
  	default:
  		return -ENOIOCTLCMD;
  	}
  
  	return 0;
  }
  
  #ifdef CONFIG_PROC_FS
  
  static void *nr_info_start(struct seq_file *seq, loff_t *pos)
  {
  	spin_lock_bh(&nr_list_lock);
  	return seq_hlist_start_head(&nr_list, *pos);
  }
  
  static void *nr_info_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	return seq_hlist_next(v, &nr_list, pos);
  }
  
  static void nr_info_stop(struct seq_file *seq, void *v)
  {
  	spin_unlock_bh(&nr_list_lock);
  }
  
  static int nr_info_show(struct seq_file *seq, void *v)
  {
  	struct sock *s = sk_entry(v);
  	struct net_device *dev;
  	struct nr_sock *nr;
  	const char *devname;
  	char buf[11];
  
  	if (v == SEQ_START_TOKEN)
  		seq_puts(seq,
  "user_addr dest_node src_node  dev    my  your  st  vs  vr  va    t1     t2     t4      idle   n2  wnd Snd-Q Rcv-Q inode\n");
  
  	else {
  
  		bh_lock_sock(s);
  		nr = nr_sk(s);
  
  		if ((dev = nr->device) == NULL)
  			devname = "???";
  		else
  			devname = dev->name;
  
  		seq_printf(seq, "%-9s ", ax2asc(buf, &nr->user_addr));
  		seq_printf(seq, "%-9s ", ax2asc(buf, &nr->dest_addr));
  		seq_printf(seq,
  "%-9s %-3s  %02X/%02X %02X/%02X %2d %3d %3d %3d %3lu/%03lu %2lu/%02lu %3lu/%03lu %3lu/%03lu %2d/%02d %3d %5d %5d %ld\n",
  			ax2asc(buf, &nr->source_addr),
  			devname,
  			nr->my_index,
  			nr->my_id,
  			nr->your_index,
  			nr->your_id,
  			nr->state,
  			nr->vs,
  			nr->vr,
  			nr->va,
  			ax25_display_timer(&nr->t1timer) / HZ,
  			nr->t1 / HZ,
  			ax25_display_timer(&nr->t2timer) / HZ,
  			nr->t2 / HZ,
  			ax25_display_timer(&nr->t4timer) / HZ,
  			nr->t4 / HZ,
  			ax25_display_timer(&nr->idletimer) / (60 * HZ),
  			nr->idle / (60 * HZ),
  			nr->n2count,
  			nr->n2,
  			nr->window,
  			sk_wmem_alloc_get(s),
  			sk_rmem_alloc_get(s),
  			s->sk_socket ? SOCK_INODE(s->sk_socket)->i_ino : 0L);
  
  		bh_unlock_sock(s);
  	}
  	return 0;
  }
  
  static const struct seq_operations nr_info_seqops = {
  	.start = nr_info_start,
  	.next = nr_info_next,
  	.stop = nr_info_stop,
  	.show = nr_info_show,
  };
  
  static int nr_info_open(struct inode *inode, struct file *file)
  {
  	return seq_open(file, &nr_info_seqops);
  }
  
  static const struct file_operations nr_info_fops = {
  	.owner = THIS_MODULE,
  	.open = nr_info_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = seq_release,
  };
  #endif	/* CONFIG_PROC_FS */
  
  static const struct net_proto_family nr_family_ops = {
  	.family		=	PF_NETROM,
  	.create		=	nr_create,
  	.owner		=	THIS_MODULE,
  };
  
  static const struct proto_ops nr_proto_ops = {
  	.family		=	PF_NETROM,
  	.owner		=	THIS_MODULE,
  	.release	=	nr_release,
  	.bind		=	nr_bind,
  	.connect	=	nr_connect,
  	.socketpair	=	sock_no_socketpair,
  	.accept		=	nr_accept,
  	.getname	=	nr_getname,
  	.poll		=	datagram_poll,
  	.ioctl		=	nr_ioctl,
  	.listen		=	nr_listen,
  	.shutdown	=	sock_no_shutdown,
  	.setsockopt	=	nr_setsockopt,
  	.getsockopt	=	nr_getsockopt,
  	.sendmsg	=	nr_sendmsg,
  	.recvmsg	=	nr_recvmsg,
  	.mmap		=	sock_no_mmap,
  	.sendpage	=	sock_no_sendpage,
  };
  
  static struct notifier_block nr_dev_notifier = {
  	.notifier_call	=	nr_device_event,
  };
  
  static struct net_device **dev_nr;
  
  static struct ax25_protocol nr_pid = {
  	.pid	= AX25_P_NETROM,
  	.func	= nr_route_frame
  };
  
  static struct ax25_linkfail nr_linkfail_notifier = {
  	.func	= nr_link_failed,
  };
  
  static int __init nr_proto_init(void)
  {
  	int i;
  	int rc = proto_register(&nr_proto, 0);
  
  	if (rc != 0)
  		goto out;
  
  	if (nr_ndevs > 0x7fffffff/sizeof(struct net_device *)) {
  		printk(KERN_ERR "NET/ROM: nr_proto_init - nr_ndevs parameter to large\n");
  		return -1;
  	}
  
  	dev_nr = kzalloc(nr_ndevs * sizeof(struct net_device *), GFP_KERNEL);
  	if (dev_nr == NULL) {
  		printk(KERN_ERR "NET/ROM: nr_proto_init - unable to allocate device array\n");
  		return -1;
  	}
  
  	for (i = 0; i < nr_ndevs; i++) {
  		char name[IFNAMSIZ];
  		struct net_device *dev;
  
  		sprintf(name, "nr%d", i);
  		dev = alloc_netdev(0, name, nr_setup);
  		if (!dev) {
  			printk(KERN_ERR "NET/ROM: nr_proto_init - unable to allocate device structure\n");
  			goto fail;
  		}
  
  		dev->base_addr = i;
  		if (register_netdev(dev)) {
  			printk(KERN_ERR "NET/ROM: nr_proto_init - unable to register network device\n");
  			free_netdev(dev);
  			goto fail;
  		}
  		nr_set_lockdep_key(dev);
  		dev_nr[i] = dev;
  	}
  
  	if (sock_register(&nr_family_ops)) {
  		printk(KERN_ERR "NET/ROM: nr_proto_init - unable to register socket family\n");
  		goto fail;
  	}
  
  	register_netdevice_notifier(&nr_dev_notifier);
  
  	ax25_register_pid(&nr_pid);
  	ax25_linkfail_register(&nr_linkfail_notifier);
  
  #ifdef CONFIG_SYSCTL
  	nr_register_sysctl();
  #endif
  
  	nr_loopback_init();
  
  	proc_create("nr", S_IRUGO, init_net.proc_net, &nr_info_fops);
  	proc_create("nr_neigh", S_IRUGO, init_net.proc_net, &nr_neigh_fops);
  	proc_create("nr_nodes", S_IRUGO, init_net.proc_net, &nr_nodes_fops);
  out:
  	return rc;
  fail:
  	while (--i >= 0) {
  		unregister_netdev(dev_nr[i]);
  		free_netdev(dev_nr[i]);
  	}
  	kfree(dev_nr);
  	proto_unregister(&nr_proto);
  	rc = -1;
  	goto out;
  }
  
  module_init(nr_proto_init);
  
  module_param(nr_ndevs, int, 0);
  MODULE_PARM_DESC(nr_ndevs, "number of NET/ROM devices");
  
  MODULE_AUTHOR("Jonathan Naylor G4KLX <g4klx@g4klx.demon.co.uk>");
  MODULE_DESCRIPTION("The amateur radio NET/ROM network and transport layer protocol");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_NETPROTO(PF_NETROM);
  
  static void __exit nr_exit(void)
  {
  	int i;
  
  	remove_proc_entry("nr", init_net.proc_net);
  	remove_proc_entry("nr_neigh", init_net.proc_net);
  	remove_proc_entry("nr_nodes", init_net.proc_net);
  	nr_loopback_clear();
  
  	nr_rt_free();
  
  #ifdef CONFIG_SYSCTL
  	nr_unregister_sysctl();
  #endif
  
  	ax25_linkfail_release(&nr_linkfail_notifier);
  	ax25_protocol_release(AX25_P_NETROM);
  
  	unregister_netdevice_notifier(&nr_dev_notifier);
  
  	sock_unregister(PF_NETROM);
  
  	for (i = 0; i < nr_ndevs; i++) {
  		struct net_device *dev = dev_nr[i];
  		if (dev) {
  			unregister_netdev(dev);
  			free_netdev(dev);
  		}
  	}
  
  	kfree(dev_nr);
  	proto_unregister(&nr_proto);
  }
  module_exit(nr_exit);
  