[AX.25]: Reference counting for AX.25 routes.
[linux-2.6.git] / net / ax25 / ax25_route.c
1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License as published by
4  * the Free Software Foundation; either version 2 of the License, or
5  * (at your option) any later version.
6  *
7  * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
8  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
9  * Copyright (C) Steven Whitehouse GW7RRM (stevew@acm.org)
10  * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
11  * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
12  * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
13  */
14
15 #include <linux/capability.h>
16 #include <linux/errno.h>
17 #include <linux/types.h>
18 #include <linux/socket.h>
19 #include <linux/timer.h>
20 #include <linux/in.h>
21 #include <linux/kernel.h>
22 #include <linux/sched.h>
23 #include <linux/string.h>
24 #include <linux/sockios.h>
25 #include <linux/net.h>
26 #include <net/ax25.h>
27 #include <linux/inet.h>
28 #include <linux/netdevice.h>
29 #include <linux/if_arp.h>
30 #include <linux/skbuff.h>
31 #include <linux/spinlock.h>
32 #include <net/sock.h>
33 #include <asm/uaccess.h>
34 #include <asm/system.h>
35 #include <linux/fcntl.h>
36 #include <linux/mm.h>
37 #include <linux/interrupt.h>
38 #include <linux/init.h>
39 #include <linux/seq_file.h>
40
41 static ax25_route *ax25_route_list;
42 static DEFINE_RWLOCK(ax25_route_lock);
43
44 void ax25_rt_device_down(struct net_device *dev)
45 {
46         ax25_route *s, *t, *ax25_rt;
47
48         write_lock(&ax25_route_lock);
49         ax25_rt = ax25_route_list;
50         while (ax25_rt != NULL) {
51                 s       = ax25_rt;
52                 ax25_rt = ax25_rt->next;
53
54                 if (s->dev == dev) {
55                         if (ax25_route_list == s) {
56                                 ax25_route_list = s->next;
57                                 kfree(s->digipeat);
58                                 kfree(s);
59                         } else {
60                                 for (t = ax25_route_list; t != NULL; t = t->next) {
61                                         if (t->next == s) {
62                                                 t->next = s->next;
63                                                 kfree(s->digipeat);
64                                                 kfree(s);
65                                                 break;
66                                         }
67                                 }
68                         }
69                 }
70         }
71         write_unlock(&ax25_route_lock);
72 }
73
74 static int ax25_rt_add(struct ax25_routes_struct *route)
75 {
76         ax25_route *ax25_rt;
77         ax25_dev *ax25_dev;
78         int i;
79
80         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
81                 return -EINVAL;
82         if (route->digi_count > AX25_MAX_DIGIS)
83                 return -EINVAL;
84
85         write_lock(&ax25_route_lock);
86
87         ax25_rt = ax25_route_list;
88         while (ax25_rt != NULL) {
89                 if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
90                             ax25_rt->dev == ax25_dev->dev) {
91                         kfree(ax25_rt->digipeat);
92                         ax25_rt->digipeat = NULL;
93                         if (route->digi_count != 0) {
94                                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
95                                         write_unlock(&ax25_route_lock);
96                                         return -ENOMEM;
97                                 }
98                                 ax25_rt->digipeat->lastrepeat = -1;
99                                 ax25_rt->digipeat->ndigi      = route->digi_count;
100                                 for (i = 0; i < route->digi_count; i++) {
101                                         ax25_rt->digipeat->repeated[i] = 0;
102                                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
103                                 }
104                         }
105                         write_unlock(&ax25_route_lock);
106                         return 0;
107                 }
108                 ax25_rt = ax25_rt->next;
109         }
110
111         if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
112                 write_unlock(&ax25_route_lock);
113                 return -ENOMEM;
114         }
115
116         atomic_set(&ax25_rt->refcount, 1);
117         ax25_rt->callsign     = route->dest_addr;
118         ax25_rt->dev          = ax25_dev->dev;
119         ax25_rt->digipeat     = NULL;
120         ax25_rt->ip_mode      = ' ';
121         if (route->digi_count != 0) {
122                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
123                         write_unlock(&ax25_route_lock);
124                         kfree(ax25_rt);
125                         return -ENOMEM;
126                 }
127                 ax25_rt->digipeat->lastrepeat = -1;
128                 ax25_rt->digipeat->ndigi      = route->digi_count;
129                 for (i = 0; i < route->digi_count; i++) {
130                         ax25_rt->digipeat->repeated[i] = 0;
131                         ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
132                 }
133         }
134         ax25_rt->next   = ax25_route_list;
135         ax25_route_list = ax25_rt;
136         write_unlock(&ax25_route_lock);
137
138         return 0;
139 }
140
141 void __ax25_put_route(ax25_route *ax25_rt)
142 {
143         kfree(ax25_rt->digipeat);
144         kfree(ax25_rt);
145 }
146
147 static int ax25_rt_del(struct ax25_routes_struct *route)
148 {
149         ax25_route *s, *t, *ax25_rt;
150         ax25_dev *ax25_dev;
151
152         if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
153                 return -EINVAL;
154
155         write_lock(&ax25_route_lock);
156
157         ax25_rt = ax25_route_list;
158         while (ax25_rt != NULL) {
159                 s       = ax25_rt;
160                 ax25_rt = ax25_rt->next;
161                 if (s->dev == ax25_dev->dev &&
162                     ax25cmp(&route->dest_addr, &s->callsign) == 0) {
163                         if (ax25_route_list == s) {
164                                 ax25_route_list = s->next;
165                                 ax25_put_route(s);
166                         } else {
167                                 for (t = ax25_route_list; t != NULL; t = t->next) {
168                                         if (t->next == s) {
169                                                 t->next = s->next;
170                                                 ax25_put_route(s);
171                                                 break;
172                                         }
173                                 }
174                         }
175                 }
176         }
177         write_unlock(&ax25_route_lock);
178
179         return 0;
180 }
181
182 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
183 {
184         ax25_route *ax25_rt;
185         ax25_dev *ax25_dev;
186         int err = 0;
187
188         if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
189                 return -EINVAL;
190
191         write_lock(&ax25_route_lock);
192
193         ax25_rt = ax25_route_list;
194         while (ax25_rt != NULL) {
195                 if (ax25_rt->dev == ax25_dev->dev &&
196                     ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
197                         switch (rt_option->cmd) {
198                         case AX25_SET_RT_IPMODE:
199                                 switch (rt_option->arg) {
200                                 case ' ':
201                                 case 'D':
202                                 case 'V':
203                                         ax25_rt->ip_mode = rt_option->arg;
204                                         break;
205                                 default:
206                                         err = -EINVAL;
207                                         goto out;
208                                 }
209                                 break;
210                         default:
211                                 err = -EINVAL;
212                                 goto out;
213                         }
214                 }
215                 ax25_rt = ax25_rt->next;
216         }
217
218 out:
219         write_unlock(&ax25_route_lock);
220         return err;
221 }
222
223 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
224 {
225         struct ax25_route_opt_struct rt_option;
226         struct ax25_routes_struct route;
227
228         switch (cmd) {
229         case SIOCADDRT:
230                 if (copy_from_user(&route, arg, sizeof(route)))
231                         return -EFAULT;
232                 return ax25_rt_add(&route);
233
234         case SIOCDELRT:
235                 if (copy_from_user(&route, arg, sizeof(route)))
236                         return -EFAULT;
237                 return ax25_rt_del(&route);
238
239         case SIOCAX25OPTRT:
240                 if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
241                         return -EFAULT;
242                 return ax25_rt_opt(&rt_option);
243
244         default:
245                 return -EINVAL;
246         }
247 }
248
249 #ifdef CONFIG_PROC_FS
250
251 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
252 {
253         struct ax25_route *ax25_rt;
254         int i = 1;
255  
256         read_lock(&ax25_route_lock);
257         if (*pos == 0)
258                 return SEQ_START_TOKEN;
259
260         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
261                 if (i == *pos)
262                         return ax25_rt;
263                 ++i;
264         }
265
266         return NULL;
267 }
268
269 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
270 {
271         ++*pos;
272         return (v == SEQ_START_TOKEN) ? ax25_route_list : 
273                 ((struct ax25_route *) v)->next;
274 }
275
276 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
277 {
278         read_unlock(&ax25_route_lock);
279 }
280
281 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
282 {
283         char buf[11];
284
285         if (v == SEQ_START_TOKEN)
286                 seq_puts(seq, "callsign  dev  mode digipeaters\n");
287         else {
288                 struct ax25_route *ax25_rt = v;
289                 const char *callsign;
290                 int i;
291
292                 if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
293                         callsign = "default";
294                 else
295                         callsign = ax2asc(buf, &ax25_rt->callsign);
296
297                 seq_printf(seq, "%-9s %-4s",
298                         callsign,
299                         ax25_rt->dev ? ax25_rt->dev->name : "???");
300
301                 switch (ax25_rt->ip_mode) {
302                 case 'V':
303                         seq_puts(seq, "   vc");
304                         break;
305                 case 'D':
306                         seq_puts(seq, "   dg");
307                         break;
308                 default:
309                         seq_puts(seq, "    *");
310                         break;
311                 }
312
313                 if (ax25_rt->digipeat != NULL)
314                         for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
315                                 seq_printf(seq, " %s",
316                                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
317
318                 seq_puts(seq, "\n");
319         }
320         return 0;
321 }
322
323 static struct seq_operations ax25_rt_seqops = {
324         .start = ax25_rt_seq_start,
325         .next = ax25_rt_seq_next,
326         .stop = ax25_rt_seq_stop,
327         .show = ax25_rt_seq_show,
328 };
329
330 static int ax25_rt_info_open(struct inode *inode, struct file *file)
331 {
332         return seq_open(file, &ax25_rt_seqops);
333 }
334
335 struct file_operations ax25_route_fops = {
336         .owner = THIS_MODULE,
337         .open = ax25_rt_info_open,
338         .read = seq_read,
339         .llseek = seq_lseek,
340         .release = seq_release,
341 };
342
343 #endif
344
345 /*
346  *      Find AX.25 route
347  *
348  *      Only routes with a reference count of zero can be destroyed.
349  */
350 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
351 {
352         ax25_route *ax25_spe_rt = NULL;
353         ax25_route *ax25_def_rt = NULL;
354         ax25_route *ax25_rt;
355
356         read_lock(&ax25_route_lock);
357         /*
358          *      Bind to the physical interface we heard them on, or the default
359          *      route if none is found;
360          */
361         for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
362                 if (dev == NULL) {
363                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
364                                 ax25_spe_rt = ax25_rt;
365                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
366                                 ax25_def_rt = ax25_rt;
367                 } else {
368                         if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
369                                 ax25_spe_rt = ax25_rt;
370                         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
371                                 ax25_def_rt = ax25_rt;
372                 }
373         }
374
375         ax25_rt = ax25_def_rt;
376         if (ax25_spe_rt != NULL)
377                 ax25_rt = ax25_spe_rt;
378
379         if (ax25_rt != NULL)
380                 ax25_hold_route(ax25_rt);
381
382         read_unlock(&ax25_route_lock);
383
384         return ax25_rt;
385 }
386
387 /*
388  *      Adjust path: If you specify a default route and want to connect
389  *      a target on the digipeater path but w/o having a special route
390  *      set before, the path has to be truncated from your target on.
391  */
392 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
393 {
394         int k;
395
396         for (k = 0; k < digipeat->ndigi; k++) {
397                 if (ax25cmp(addr, &digipeat->calls[k]) == 0)
398                         break;
399         }
400
401         digipeat->ndigi = k;
402 }
403
404
405 /*
406  *      Find which interface to use.
407  */
408 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
409 {
410         ax25_uid_assoc *user;
411         ax25_route *ax25_rt;
412         int err;
413
414         if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
415                 return -EHOSTUNREACH;
416
417         if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
418                 err = -EHOSTUNREACH;
419                 goto put;
420         }
421
422         user = ax25_findbyuid(current->euid);
423         if (user) {
424                 ax25->source_addr = user->call;
425                 ax25_uid_put(user);
426         } else {
427                 if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
428                         err = -EPERM;
429                         goto put;
430                 }
431                 ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
432         }
433
434         if (ax25_rt->digipeat != NULL) {
435                 if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
436                         err = -ENOMEM;
437                         goto put;
438                 }
439                 memcpy(ax25->digipeat, ax25_rt->digipeat, sizeof(ax25_digi));
440                 ax25_adjust_path(addr, ax25->digipeat);
441         }
442
443         if (ax25->sk != NULL) {
444                 bh_lock_sock(ax25->sk);
445                 sock_reset_flag(ax25->sk, SOCK_ZAPPED);
446                 bh_unlock_sock(ax25->sk);
447         }
448
449 put:
450         ax25_put_route(ax25_rt);
451
452         return 0;
453 }
454
455 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
456         ax25_address *dest, ax25_digi *digi)
457 {
458         struct sk_buff *skbn;
459         unsigned char *bp;
460         int len;
461
462         len = digi->ndigi * AX25_ADDR_LEN;
463
464         if (skb_headroom(skb) < len) {
465                 if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
466                         printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
467                         return NULL;
468                 }
469
470                 if (skb->sk != NULL)
471                         skb_set_owner_w(skbn, skb->sk);
472
473                 kfree_skb(skb);
474
475                 skb = skbn;
476         }
477
478         bp = skb_push(skb, len);
479
480         ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
481
482         return skb;
483 }
484
485 /*
486  *      Free all memory associated with routing structures.
487  */
488 void __exit ax25_rt_free(void)
489 {
490         ax25_route *s, *ax25_rt = ax25_route_list;
491
492         write_lock(&ax25_route_lock);
493         while (ax25_rt != NULL) {
494                 s       = ax25_rt;
495                 ax25_rt = ax25_rt->next;
496
497                 kfree(s->digipeat);
498                 kfree(s);
499         }
500         write_unlock(&ax25_route_lock);
501 }