aboutsummaryrefslogblamecommitdiffstats
path: root/net/netrom/af_netrom.c
blob: d44981f5a6195b4a017552b16e5a4ca82db98c88 (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463












                                                                       
                             



























                                                      
                           















                                                                       
                                                                     





                                      
                                           











































































































































































































































































































































































































                                                                                       
                                 











































































                                                                             

                             





































                                                                                                             




                                                     




                                                                                
                                                  

                 


















                                                                   

                                    







































                                                                                                               




                                                     




                                                                         
                                                  

                 


































































































































































































                                                                            


                                                       

                                                                        




                                                                 







































                                                                                    





                                                                                
                   



                                                          





















































































































































































































































                                                                                                      


                            

                              









                                                                         

                              







                                                                                              
                              
                                                   












                                 




                               



                                                           
                                    
         










































                                                                     
                     














                                                                                                                             

                                                                      

                                                                                                                        
                                                      























































                                                                             
                                              





















































                                                                                                            
                                                                              


























































































                                                                                                          
/*
 * 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/config.h>
#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/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/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/termios.h>	/* For TIOCINQ/OUTQ */
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <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;

/*
 *	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;
	struct hlist_node *node;

	spin_lock_bh(&nr_list_lock);
	sk_for_each(s, node, &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 = (struct net_device *)ptr;

	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;
	struct hlist_node *node;

	spin_lock_bh(&nr_list_lock);
	sk_for_each(s, node, &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;
	struct hlist_node *node;

	spin_lock_bh(&nr_list_lock);
	sk_for_each(s, node, &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;
	struct hlist_node *node;

	spin_lock_bh(&nr_list_lock);
	sk_for_each(s, node, &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 (atomic_read(&sk->sk_wmem_alloc) ||
	    atomic_read(&sk->sk_rmem_alloc)) {
		/* 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, int optlen)
{
	struct sock *sk = sock->sk;
	struct nr_sock *nr = nr_sk(sk);
	int opt;

	if (level != SOL_NETROM)
		return -ENOPROTOOPT;

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

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

	switch (optname) {
	case NETROM_T1:
		if (opt < 1)
			return -EINVAL;
		nr->t1 = opt * HZ;
		return 0;

	case NETROM_T2:
		if (opt < 1)
			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)
			return -EINVAL;
		nr->t4 = opt * HZ;
		return 0;

	case NETROM_IDLE:
		if (opt < 0)
			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 socket *sock, int protocol)
{
	struct sock *sk;
	struct nr_sock *nr;

	if (sock->type != SOCK_SEQPACKET || protocol != 0)
		return -ESOCKTNOSUPPORT;

	if ((sk = sk_alloc(PF_NETROM, GFP_ATOMIC, &nr_proto, 1)) == 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     = sysctl_netrom_transport_timeout;
	nr->t2     = sysctl_netrom_transport_acknowledge_delay;
	nr->n2     = sysctl_netrom_transport_maximum_tries;
	nr->t4     = sysctl_netrom_transport_busy_delay;
	nr->idle   = 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;

	if ((sk = sk_alloc(PF_NETROM, GFP_ATOMIC, osk->sk_prot, 1)) == NULL)
		return NULL;

	nr = nr_sk(sk);

	sock_init_data(NULL, sk);

	sk->sk_type     = osk->sk_type;
	sk->sk_socket   = osk->sk_socket;
	sk->sk_priority = osk->sk_priority;
	sk->sk_protocol = osk->sk_protocol;
	sk->sk_rcvbuf   = osk->sk_rcvbuf;
	sk->sk_sndbuf   = osk->sk_sndbuf;
	sk->sk_state    = TCP_ESTABLISHED;
	sk->sk_sleep    = osk->sk_sleep;
	sock_copy_flags(sk, osk);

	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);
	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_orphan(sk);
		sock_set_flag(sk, SOCK_DESTROY);
		sk->sk_socket   = NULL;
		break;

	default:
		sk->sk_socket = NULL;
		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) {
		SOCK_DEBUG(sk, "NET/ROM: bind failed: invalid node callsign\n");
		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 -EACCES;
		}
		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);
	SOCK_DEBUG(sk, "NET/ROM: socket is bound\n");
	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;

	lock_sock(sk);
	if (sk->sk_state == TCP_ESTABLISHED && sock->state == SS_CONNECTING) {
		sock->state = SS_CONNECTED;
		release_sock(sk);
		return 0;	/* Connect completed during a ERESTARTSYS event */
	}

	if (sk->sk_state == TCP_CLOSE && sock->state == SS_CONNECTING) {
		sock->state = SS_UNCONNECTED;
		release_sock(sk);
		return -ECONNREFUSED;
	}

	if (sk->sk_state == TCP_ESTABLISHED) {
		release_sock(sk);
		return -EISCONN;	/* No reconnect on a seqpacket socket */
	}

	sk->sk_state   = TCP_CLOSE;	
	sock->state = SS_UNCONNECTED;

	if (addr_len != sizeof(struct sockaddr_ax25) && addr_len != sizeof(struct full_sockaddr_ax25)) {
		release_sock(sk);
		return -EINVAL;
	}
	if (addr->sax25_family != AF_NETROM) {
		release_sock(sk);
		return -EINVAL;
	}
	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) {
			release_sock(sk);
			return -ENETUNREACH;
		}
		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);
				release_sock(sk);
				return -EPERM;
			}
			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)) {
		release_sock(sk);
		return -EINPROGRESS;
	}
		
	/*
	 * A Connect Ack with Choke or timeout or failed routing will go to
	 * closed.
	 */
	if (sk->sk_state == TCP_SYN_SENT) {
		struct task_struct *tsk = current;
		DECLARE_WAITQUEUE(wait, tsk);

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

	if (sk->sk_state != TCP_ESTABLISHED) {
		sock->state = SS_UNCONNECTED;
		release_sock(sk);
		return sock_error(sk);	/* Always set at this point */
	}

	sock->state = SS_CONNECTED;
	release_sock(sk);

	return 0;
}

static int nr_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct task_struct *tsk = current;
	DECLARE_WAITQUEUE(wait, tsk);
	struct sk_buff *skb;
	struct sock *newsk;
	struct sock *sk;
	int err = 0;

	if ((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 write queue this time is holding sockets ready to use
	 *	hooked into the SABM we saved
	 */
	add_wait_queue(sk->sk_sleep, &wait);
	for (;;) {
		skb = skb_dequeue(&sk->sk_receive_queue);
		if (skb)
			break;

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

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

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

out:
	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);

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

		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->h.raw = skb->data;

		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->sk_ack_backlog++;

	nr_insert_socket(make);

	skb_queue_head(&sk->sk_receive_queue, skb);

	nr_start_heartbeat(make);
	nr_start_idletimer(make);

	if (!sock_flag(sk, SOCK_DEAD))
		sk->sk_data_ready(sk, skb->len);

	bh_unlock_sock(sk);
	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);
	struct sockaddr_ax25 *usax = (struct sockaddr_ax25 *)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;
	}

	SOCK_DEBUG(sk, "NET/ROM: sendto: Addresses built.\n");

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

	/*
	 *	Push down the NET/ROM header
	 */

	asmptr = skb_push(skb, NR_TRANSPORT_LEN);
	SOCK_DEBUG(sk, "Building NET/ROM Header.\n");

	/* 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;
	SOCK_DEBUG(sk, "Built header.\n");

	/*
	 *	Put the data on the end
	 */

	skb->h.raw = skb_put(skb, len);

	asmptr = skb->h.raw;
	SOCK_DEBUG(sk, "NET/ROM: Appending user data\n");

	/* User data follows immediately after the NET/ROM transport header */
	if (memcpy_fromiovec(asmptr, msg->msg_iov, len)) {
		kfree_skb(skb);
		err = -EFAULT;
		goto out;
	}

	SOCK_DEBUG(sk, "NET/ROM: Transmitting buffer\n");

	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;
	struct sockaddr_ax25 *sax = (struct sockaddr_ax25 *)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->h.raw = skb->data;
	copied     = skb->len;

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

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

	if (sax != NULL) {
		sax->sax25_family = AF_NETROM;
		memcpy(sax->sax25_call.ax25_call, skb->data + 7, 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 - atomic_read(&sk->sk_wmem_alloc);
		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 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)
{
	struct sock *s;
	struct hlist_node *node;
	int i = 1;

	spin_lock_bh(&nr_list_lock);
	if (*pos == 0)
		return SEQ_START_TOKEN;

	sk_for_each(s, node, &nr_list) {
		if (i == *pos)
			return s;
		++i;
	}
	return NULL;
}

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

	return (v == SEQ_START_TOKEN) ? sk_head(&nr_list) 
		: sk_next((struct sock *)v);
}
	
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 = 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,
			atomic_read(&s->sk_wmem_alloc),
			atomic_read(&s->sk_rmem_alloc),
			s->sk_socket ? SOCK_INODE(s->sk_socket)->i_ino : 0L);

		bh_unlock_sock(s);
	}
	return 0;
}

static 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 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 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 char banner[] __initdata = KERN_INFO "G4KLX NET/ROM for Linux. Version 0.7 for AX25.037 Linux 2.4\n";

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 = kmalloc(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;
	}

	memset(dev_nr, 0x00, nr_ndevs * sizeof(struct net_device *));

	for (i = 0; i < nr_ndevs; i++) {
		char name[IFNAMSIZ];
		struct net_device *dev;

		sprintf(name, "nr%d", i);
		dev = alloc_netdev(sizeof(struct nr_private), 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;
		}
		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);
	printk(banner);

	ax25_protocol_register(AX25_P_NETROM, nr_route_frame);
	ax25_linkfail_register(nr_link_failed);

#ifdef CONFIG_SYSCTL
	nr_register_sysctl();
#endif

	nr_loopback_init();

	proc_net_fops_create("nr", S_IRUGO, &nr_info_fops);
	proc_net_fops_create("nr_neigh", S_IRUGO, &nr_neigh_fops);
	proc_net_fops_create("nr_nodes", S_IRUGO, &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;

	proc_net_remove("nr");
	proc_net_remove("nr_neigh");
	proc_net_remove("nr_nodes");
	nr_loopback_clear();

	nr_rt_free();

#ifdef CONFIG_SYSCTL
	nr_unregister_sysctl();
#endif

	ax25_linkfail_release(nr_link_failed);
	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);