xref: /openbmc/linux/net/ax25/ax25_route.c (revision 64c70b1c) 
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 __must_check 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 const 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 		ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
436 					 GFP_ATOMIC);
437 		if (ax25->digipeat == NULL) {
438 			err = -ENOMEM;
439 			goto put;
440 		}
441 		ax25_adjust_path(addr, ax25->digipeat);
442 	}
443 
444 	if (ax25->sk != NULL) {
445 		bh_lock_sock(ax25->sk);
446 		sock_reset_flag(ax25->sk, SOCK_ZAPPED);
447 		bh_unlock_sock(ax25->sk);
448 	}
449 
450 put:
451 	ax25_put_route(ax25_rt);
452 
453 	return 0;
454 }
455 
456 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
457 	ax25_address *dest, ax25_digi *digi)
458 {
459 	struct sk_buff *skbn;
460 	unsigned char *bp;
461 	int len;
462 
463 	len = digi->ndigi * AX25_ADDR_LEN;
464 
465 	if (skb_headroom(skb) < len) {
466 		if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
467 			printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
468 			return NULL;
469 		}
470 
471 		if (skb->sk != NULL)
472 			skb_set_owner_w(skbn, skb->sk);
473 
474 		kfree_skb(skb);
475 
476 		skb = skbn;
477 	}
478 
479 	bp = skb_push(skb, len);
480 
481 	ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
482 
483 	return skb;
484 }
485 
486 /*
487  *	Free all memory associated with routing structures.
488  */
489 void __exit ax25_rt_free(void)
490 {
491 	ax25_route *s, *ax25_rt = ax25_route_list;
492 
493 	write_lock(&ax25_route_lock);
494 	while (ax25_rt != NULL) {
495 		s       = ax25_rt;
496 		ax25_rt = ax25_rt->next;
497 
498 		kfree(s->digipeat);
499 		kfree(s);
500 	}
501 	write_unlock(&ax25_route_lock);
502 }
503