xref: /openbmc/linux/net/ax25/ax25_route.c (revision 3b64b188) 
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 <linux/slab.h>
27 #include <net/ax25.h>
28 #include <linux/inet.h>
29 #include <linux/netdevice.h>
30 #include <linux/if_arp.h>
31 #include <linux/skbuff.h>
32 #include <linux/spinlock.h>
33 #include <net/sock.h>
34 #include <asm/uaccess.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 #include <linux/export.h>
41 
42 static ax25_route *ax25_route_list;
43 static DEFINE_RWLOCK(ax25_route_lock);
44 
45 void ax25_rt_device_down(struct net_device *dev)
46 {
47 	ax25_route *s, *t, *ax25_rt;
48 
49 	write_lock_bh(&ax25_route_lock);
50 	ax25_rt = ax25_route_list;
51 	while (ax25_rt != NULL) {
52 		s       = ax25_rt;
53 		ax25_rt = ax25_rt->next;
54 
55 		if (s->dev == dev) {
56 			if (ax25_route_list == s) {
57 				ax25_route_list = s->next;
58 				kfree(s->digipeat);
59 				kfree(s);
60 			} else {
61 				for (t = ax25_route_list; t != NULL; t = t->next) {
62 					if (t->next == s) {
63 						t->next = s->next;
64 						kfree(s->digipeat);
65 						kfree(s);
66 						break;
67 					}
68 				}
69 			}
70 		}
71 	}
72 	write_unlock_bh(&ax25_route_lock);
73 }
74 
75 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
76 {
77 	ax25_route *ax25_rt;
78 	ax25_dev *ax25_dev;
79 	int i;
80 
81 	if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
82 		return -EINVAL;
83 	if (route->digi_count > AX25_MAX_DIGIS)
84 		return -EINVAL;
85 
86 	write_lock_bh(&ax25_route_lock);
87 
88 	ax25_rt = ax25_route_list;
89 	while (ax25_rt != NULL) {
90 		if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
91 			    ax25_rt->dev == ax25_dev->dev) {
92 			kfree(ax25_rt->digipeat);
93 			ax25_rt->digipeat = NULL;
94 			if (route->digi_count != 0) {
95 				if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
96 					write_unlock_bh(&ax25_route_lock);
97 					return -ENOMEM;
98 				}
99 				ax25_rt->digipeat->lastrepeat = -1;
100 				ax25_rt->digipeat->ndigi      = route->digi_count;
101 				for (i = 0; i < route->digi_count; i++) {
102 					ax25_rt->digipeat->repeated[i] = 0;
103 					ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
104 				}
105 			}
106 			write_unlock_bh(&ax25_route_lock);
107 			return 0;
108 		}
109 		ax25_rt = ax25_rt->next;
110 	}
111 
112 	if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
113 		write_unlock_bh(&ax25_route_lock);
114 		return -ENOMEM;
115 	}
116 
117 	atomic_set(&ax25_rt->refcount, 1);
118 	ax25_rt->callsign     = route->dest_addr;
119 	ax25_rt->dev          = ax25_dev->dev;
120 	ax25_rt->digipeat     = NULL;
121 	ax25_rt->ip_mode      = ' ';
122 	if (route->digi_count != 0) {
123 		if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
124 			write_unlock_bh(&ax25_route_lock);
125 			kfree(ax25_rt);
126 			return -ENOMEM;
127 		}
128 		ax25_rt->digipeat->lastrepeat = -1;
129 		ax25_rt->digipeat->ndigi      = route->digi_count;
130 		for (i = 0; i < route->digi_count; i++) {
131 			ax25_rt->digipeat->repeated[i] = 0;
132 			ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
133 		}
134 	}
135 	ax25_rt->next   = ax25_route_list;
136 	ax25_route_list = ax25_rt;
137 	write_unlock_bh(&ax25_route_lock);
138 
139 	return 0;
140 }
141 
142 void __ax25_put_route(ax25_route *ax25_rt)
143 {
144 	kfree(ax25_rt->digipeat);
145 	kfree(ax25_rt);
146 }
147 
148 static int ax25_rt_del(struct ax25_routes_struct *route)
149 {
150 	ax25_route *s, *t, *ax25_rt;
151 	ax25_dev *ax25_dev;
152 
153 	if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
154 		return -EINVAL;
155 
156 	write_lock_bh(&ax25_route_lock);
157 
158 	ax25_rt = ax25_route_list;
159 	while (ax25_rt != NULL) {
160 		s       = ax25_rt;
161 		ax25_rt = ax25_rt->next;
162 		if (s->dev == ax25_dev->dev &&
163 		    ax25cmp(&route->dest_addr, &s->callsign) == 0) {
164 			if (ax25_route_list == s) {
165 				ax25_route_list = s->next;
166 				ax25_put_route(s);
167 			} else {
168 				for (t = ax25_route_list; t != NULL; t = t->next) {
169 					if (t->next == s) {
170 						t->next = s->next;
171 						ax25_put_route(s);
172 						break;
173 					}
174 				}
175 			}
176 		}
177 	}
178 	write_unlock_bh(&ax25_route_lock);
179 
180 	return 0;
181 }
182 
183 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
184 {
185 	ax25_route *ax25_rt;
186 	ax25_dev *ax25_dev;
187 	int err = 0;
188 
189 	if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
190 		return -EINVAL;
191 
192 	write_lock_bh(&ax25_route_lock);
193 
194 	ax25_rt = ax25_route_list;
195 	while (ax25_rt != NULL) {
196 		if (ax25_rt->dev == ax25_dev->dev &&
197 		    ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
198 			switch (rt_option->cmd) {
199 			case AX25_SET_RT_IPMODE:
200 				switch (rt_option->arg) {
201 				case ' ':
202 				case 'D':
203 				case 'V':
204 					ax25_rt->ip_mode = rt_option->arg;
205 					break;
206 				default:
207 					err = -EINVAL;
208 					goto out;
209 				}
210 				break;
211 			default:
212 				err = -EINVAL;
213 				goto out;
214 			}
215 		}
216 		ax25_rt = ax25_rt->next;
217 	}
218 
219 out:
220 	write_unlock_bh(&ax25_route_lock);
221 	return err;
222 }
223 
224 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
225 {
226 	struct ax25_route_opt_struct rt_option;
227 	struct ax25_routes_struct route;
228 
229 	switch (cmd) {
230 	case SIOCADDRT:
231 		if (copy_from_user(&route, arg, sizeof(route)))
232 			return -EFAULT;
233 		return ax25_rt_add(&route);
234 
235 	case SIOCDELRT:
236 		if (copy_from_user(&route, arg, sizeof(route)))
237 			return -EFAULT;
238 		return ax25_rt_del(&route);
239 
240 	case SIOCAX25OPTRT:
241 		if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
242 			return -EFAULT;
243 		return ax25_rt_opt(&rt_option);
244 
245 	default:
246 		return -EINVAL;
247 	}
248 }
249 
250 #ifdef CONFIG_PROC_FS
251 
252 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
253 	__acquires(ax25_route_lock)
254 {
255 	struct ax25_route *ax25_rt;
256 	int i = 1;
257 
258 	read_lock(&ax25_route_lock);
259 	if (*pos == 0)
260 		return SEQ_START_TOKEN;
261 
262 	for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
263 		if (i == *pos)
264 			return ax25_rt;
265 		++i;
266 	}
267 
268 	return NULL;
269 }
270 
271 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
272 {
273 	++*pos;
274 	return (v == SEQ_START_TOKEN) ? ax25_route_list :
275 		((struct ax25_route *) v)->next;
276 }
277 
278 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
279 	__releases(ax25_route_lock)
280 {
281 	read_unlock(&ax25_route_lock);
282 }
283 
284 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
285 {
286 	char buf[11];
287 
288 	if (v == SEQ_START_TOKEN)
289 		seq_puts(seq, "callsign  dev  mode digipeaters\n");
290 	else {
291 		struct ax25_route *ax25_rt = v;
292 		const char *callsign;
293 		int i;
294 
295 		if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
296 			callsign = "default";
297 		else
298 			callsign = ax2asc(buf, &ax25_rt->callsign);
299 
300 		seq_printf(seq, "%-9s %-4s",
301 			callsign,
302 			ax25_rt->dev ? ax25_rt->dev->name : "???");
303 
304 		switch (ax25_rt->ip_mode) {
305 		case 'V':
306 			seq_puts(seq, "   vc");
307 			break;
308 		case 'D':
309 			seq_puts(seq, "   dg");
310 			break;
311 		default:
312 			seq_puts(seq, "    *");
313 			break;
314 		}
315 
316 		if (ax25_rt->digipeat != NULL)
317 			for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
318 				seq_printf(seq, " %s",
319 				     ax2asc(buf, &ax25_rt->digipeat->calls[i]));
320 
321 		seq_puts(seq, "\n");
322 	}
323 	return 0;
324 }
325 
326 static const struct seq_operations ax25_rt_seqops = {
327 	.start = ax25_rt_seq_start,
328 	.next = ax25_rt_seq_next,
329 	.stop = ax25_rt_seq_stop,
330 	.show = ax25_rt_seq_show,
331 };
332 
333 static int ax25_rt_info_open(struct inode *inode, struct file *file)
334 {
335 	return seq_open(file, &ax25_rt_seqops);
336 }
337 
338 const struct file_operations ax25_route_fops = {
339 	.owner = THIS_MODULE,
340 	.open = ax25_rt_info_open,
341 	.read = seq_read,
342 	.llseek = seq_lseek,
343 	.release = seq_release,
344 };
345 
346 #endif
347 
348 /*
349  *	Find AX.25 route
350  *
351  *	Only routes with a reference count of zero can be destroyed.
352  */
353 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
354 {
355 	ax25_route *ax25_spe_rt = NULL;
356 	ax25_route *ax25_def_rt = NULL;
357 	ax25_route *ax25_rt;
358 
359 	read_lock(&ax25_route_lock);
360 	/*
361 	 *	Bind to the physical interface we heard them on, or the default
362 	 *	route if none is found;
363 	 */
364 	for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
365 		if (dev == NULL) {
366 			if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
367 				ax25_spe_rt = ax25_rt;
368 			if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
369 				ax25_def_rt = ax25_rt;
370 		} else {
371 			if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
372 				ax25_spe_rt = ax25_rt;
373 			if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
374 				ax25_def_rt = ax25_rt;
375 		}
376 	}
377 
378 	ax25_rt = ax25_def_rt;
379 	if (ax25_spe_rt != NULL)
380 		ax25_rt = ax25_spe_rt;
381 
382 	if (ax25_rt != NULL)
383 		ax25_hold_route(ax25_rt);
384 
385 	read_unlock(&ax25_route_lock);
386 
387 	return ax25_rt;
388 }
389 
390 /*
391  *	Adjust path: If you specify a default route and want to connect
392  *      a target on the digipeater path but w/o having a special route
393  *	set before, the path has to be truncated from your target on.
394  */
395 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
396 {
397 	int k;
398 
399 	for (k = 0; k < digipeat->ndigi; k++) {
400 		if (ax25cmp(addr, &digipeat->calls[k]) == 0)
401 			break;
402 	}
403 
404 	digipeat->ndigi = k;
405 }
406 
407 
408 /*
409  *	Find which interface to use.
410  */
411 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
412 {
413 	ax25_uid_assoc *user;
414 	ax25_route *ax25_rt;
415 	int err = 0;
416 
417 	if ((ax25_rt = ax25_get_route(addr, NULL)) == NULL)
418 		return -EHOSTUNREACH;
419 
420 	if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
421 		err = -EHOSTUNREACH;
422 		goto put;
423 	}
424 
425 	user = ax25_findbyuid(current_euid());
426 	if (user) {
427 		ax25->source_addr = user->call;
428 		ax25_uid_put(user);
429 	} else {
430 		if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
431 			err = -EPERM;
432 			goto put;
433 		}
434 		ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
435 	}
436 
437 	if (ax25_rt->digipeat != NULL) {
438 		ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
439 					 GFP_ATOMIC);
440 		if (ax25->digipeat == NULL) {
441 			err = -ENOMEM;
442 			goto put;
443 		}
444 		ax25_adjust_path(addr, ax25->digipeat);
445 	}
446 
447 	if (ax25->sk != NULL) {
448 		bh_lock_sock(ax25->sk);
449 		sock_reset_flag(ax25->sk, SOCK_ZAPPED);
450 		bh_unlock_sock(ax25->sk);
451 	}
452 
453 put:
454 	ax25_put_route(ax25_rt);
455 
456 	return err;
457 }
458 
459 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
460 	ax25_address *dest, ax25_digi *digi)
461 {
462 	struct sk_buff *skbn;
463 	unsigned char *bp;
464 	int len;
465 
466 	len = digi->ndigi * AX25_ADDR_LEN;
467 
468 	if (skb_headroom(skb) < len) {
469 		if ((skbn = skb_realloc_headroom(skb, len)) == NULL) {
470 			printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
471 			return NULL;
472 		}
473 
474 		if (skb->sk != NULL)
475 			skb_set_owner_w(skbn, skb->sk);
476 
477 		consume_skb(skb);
478 
479 		skb = skbn;
480 	}
481 
482 	bp = skb_push(skb, len);
483 
484 	ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
485 
486 	return skb;
487 }
488 
489 /*
490  *	Free all memory associated with routing structures.
491  */
492 void __exit ax25_rt_free(void)
493 {
494 	ax25_route *s, *ax25_rt = ax25_route_list;
495 
496 	write_lock_bh(&ax25_route_lock);
497 	while (ax25_rt != NULL) {
498 		s       = ax25_rt;
499 		ax25_rt = ax25_rt->next;
500 
501 		kfree(s->digipeat);
502 		kfree(s);
503 	}
504 	write_unlock_bh(&ax25_route_lock);
505 }
506