xref: /openbmc/linux/net/ax25/ax25_route.c (revision 87563a04)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
5  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
6  * Copyright (C) Steven Whitehouse GW7RRM (stevew@acm.org)
7  * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
8  * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
9  * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
10  */
11 
12 #include <linux/capability.h>
13 #include <linux/errno.h>
14 #include <linux/types.h>
15 #include <linux/socket.h>
16 #include <linux/timer.h>
17 #include <linux/in.h>
18 #include <linux/kernel.h>
19 #include <linux/sched.h>
20 #include <linux/string.h>
21 #include <linux/sockios.h>
22 #include <linux/net.h>
23 #include <linux/slab.h>
24 #include <net/ax25.h>
25 #include <linux/inet.h>
26 #include <linux/netdevice.h>
27 #include <linux/if_arp.h>
28 #include <linux/skbuff.h>
29 #include <linux/spinlock.h>
30 #include <net/sock.h>
31 #include <linux/uaccess.h>
32 #include <linux/fcntl.h>
33 #include <linux/mm.h>
34 #include <linux/interrupt.h>
35 #include <linux/init.h>
36 #include <linux/seq_file.h>
37 #include <linux/export.h>
38 
39 static ax25_route *ax25_route_list;
40 DEFINE_RWLOCK(ax25_route_lock);
41 
ax25_rt_device_down(struct net_device * dev)42 void ax25_rt_device_down(struct net_device *dev)
43 {
44 	ax25_route *s, *t, *ax25_rt;
45 
46 	write_lock_bh(&ax25_route_lock);
47 	ax25_rt = ax25_route_list;
48 	while (ax25_rt != NULL) {
49 		s       = ax25_rt;
50 		ax25_rt = ax25_rt->next;
51 
52 		if (s->dev == dev) {
53 			if (ax25_route_list == s) {
54 				ax25_route_list = s->next;
55 				kfree(s->digipeat);
56 				kfree(s);
57 			} else {
58 				for (t = ax25_route_list; t != NULL; t = t->next) {
59 					if (t->next == s) {
60 						t->next = s->next;
61 						kfree(s->digipeat);
62 						kfree(s);
63 						break;
64 					}
65 				}
66 			}
67 		}
68 	}
69 	write_unlock_bh(&ax25_route_lock);
70 }
71 
ax25_rt_add(struct ax25_routes_struct * route)72 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
73 {
74 	ax25_route *ax25_rt;
75 	ax25_dev *ax25_dev;
76 	int i;
77 
78 	if (route->digi_count > AX25_MAX_DIGIS)
79 		return -EINVAL;
80 
81 	ax25_dev = ax25_addr_ax25dev(&route->port_addr);
82 	if (!ax25_dev)
83 		return -EINVAL;
84 
85 	write_lock_bh(&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_bh(&ax25_route_lock);
96 					ax25_dev_put(ax25_dev);
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 			ax25_dev_put(ax25_dev);
108 			return 0;
109 		}
110 		ax25_rt = ax25_rt->next;
111 	}
112 
113 	if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
114 		write_unlock_bh(&ax25_route_lock);
115 		ax25_dev_put(ax25_dev);
116 		return -ENOMEM;
117 	}
118 
119 	ax25_rt->callsign     = route->dest_addr;
120 	ax25_rt->dev          = ax25_dev->dev;
121 	ax25_rt->digipeat     = NULL;
122 	ax25_rt->ip_mode      = ' ';
123 	if (route->digi_count != 0) {
124 		if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
125 			write_unlock_bh(&ax25_route_lock);
126 			kfree(ax25_rt);
127 			ax25_dev_put(ax25_dev);
128 			return -ENOMEM;
129 		}
130 		ax25_rt->digipeat->lastrepeat = -1;
131 		ax25_rt->digipeat->ndigi      = route->digi_count;
132 		for (i = 0; i < route->digi_count; i++) {
133 			ax25_rt->digipeat->repeated[i] = 0;
134 			ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
135 		}
136 	}
137 	ax25_rt->next   = ax25_route_list;
138 	ax25_route_list = ax25_rt;
139 	write_unlock_bh(&ax25_route_lock);
140 	ax25_dev_put(ax25_dev);
141 
142 	return 0;
143 }
144 
__ax25_put_route(ax25_route * ax25_rt)145 void __ax25_put_route(ax25_route *ax25_rt)
146 {
147 	kfree(ax25_rt->digipeat);
148 	kfree(ax25_rt);
149 }
150 
ax25_rt_del(struct ax25_routes_struct * route)151 static int ax25_rt_del(struct ax25_routes_struct *route)
152 {
153 	ax25_route *s, *t, *ax25_rt;
154 	ax25_dev *ax25_dev;
155 
156 	if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
157 		return -EINVAL;
158 
159 	write_lock_bh(&ax25_route_lock);
160 
161 	ax25_rt = ax25_route_list;
162 	while (ax25_rt != NULL) {
163 		s       = ax25_rt;
164 		ax25_rt = ax25_rt->next;
165 		if (s->dev == ax25_dev->dev &&
166 		    ax25cmp(&route->dest_addr, &s->callsign) == 0) {
167 			if (ax25_route_list == s) {
168 				ax25_route_list = s->next;
169 				__ax25_put_route(s);
170 			} else {
171 				for (t = ax25_route_list; t != NULL; t = t->next) {
172 					if (t->next == s) {
173 						t->next = s->next;
174 						__ax25_put_route(s);
175 						break;
176 					}
177 				}
178 			}
179 		}
180 	}
181 	write_unlock_bh(&ax25_route_lock);
182 	ax25_dev_put(ax25_dev);
183 
184 	return 0;
185 }
186 
ax25_rt_opt(struct ax25_route_opt_struct * rt_option)187 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
188 {
189 	ax25_route *ax25_rt;
190 	ax25_dev *ax25_dev;
191 	int err = 0;
192 
193 	if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
194 		return -EINVAL;
195 
196 	write_lock_bh(&ax25_route_lock);
197 
198 	ax25_rt = ax25_route_list;
199 	while (ax25_rt != NULL) {
200 		if (ax25_rt->dev == ax25_dev->dev &&
201 		    ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
202 			switch (rt_option->cmd) {
203 			case AX25_SET_RT_IPMODE:
204 				switch (rt_option->arg) {
205 				case ' ':
206 				case 'D':
207 				case 'V':
208 					ax25_rt->ip_mode = rt_option->arg;
209 					break;
210 				default:
211 					err = -EINVAL;
212 					goto out;
213 				}
214 				break;
215 			default:
216 				err = -EINVAL;
217 				goto out;
218 			}
219 		}
220 		ax25_rt = ax25_rt->next;
221 	}
222 
223 out:
224 	write_unlock_bh(&ax25_route_lock);
225 	ax25_dev_put(ax25_dev);
226 	return err;
227 }
228 
ax25_rt_ioctl(unsigned int cmd,void __user * arg)229 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
230 {
231 	struct ax25_route_opt_struct rt_option;
232 	struct ax25_routes_struct route;
233 
234 	switch (cmd) {
235 	case SIOCADDRT:
236 		if (copy_from_user(&route, arg, sizeof(route)))
237 			return -EFAULT;
238 		return ax25_rt_add(&route);
239 
240 	case SIOCDELRT:
241 		if (copy_from_user(&route, arg, sizeof(route)))
242 			return -EFAULT;
243 		return ax25_rt_del(&route);
244 
245 	case SIOCAX25OPTRT:
246 		if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
247 			return -EFAULT;
248 		return ax25_rt_opt(&rt_option);
249 
250 	default:
251 		return -EINVAL;
252 	}
253 }
254 
255 #ifdef CONFIG_PROC_FS
256 
ax25_rt_seq_start(struct seq_file * seq,loff_t * pos)257 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
258 	__acquires(ax25_route_lock)
259 {
260 	struct ax25_route *ax25_rt;
261 	int i = 1;
262 
263 	read_lock(&ax25_route_lock);
264 	if (*pos == 0)
265 		return SEQ_START_TOKEN;
266 
267 	for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
268 		if (i == *pos)
269 			return ax25_rt;
270 		++i;
271 	}
272 
273 	return NULL;
274 }
275 
ax25_rt_seq_next(struct seq_file * seq,void * v,loff_t * pos)276 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
277 {
278 	++*pos;
279 	return (v == SEQ_START_TOKEN) ? ax25_route_list :
280 		((struct ax25_route *) v)->next;
281 }
282 
ax25_rt_seq_stop(struct seq_file * seq,void * v)283 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
284 	__releases(ax25_route_lock)
285 {
286 	read_unlock(&ax25_route_lock);
287 }
288 
ax25_rt_seq_show(struct seq_file * seq,void * v)289 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
290 {
291 	char buf[11];
292 
293 	if (v == SEQ_START_TOKEN)
294 		seq_puts(seq, "callsign  dev  mode digipeaters\n");
295 	else {
296 		struct ax25_route *ax25_rt = v;
297 		const char *callsign;
298 		int i;
299 
300 		if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
301 			callsign = "default";
302 		else
303 			callsign = ax2asc(buf, &ax25_rt->callsign);
304 
305 		seq_printf(seq, "%-9s %-4s",
306 			callsign,
307 			ax25_rt->dev ? ax25_rt->dev->name : "???");
308 
309 		switch (ax25_rt->ip_mode) {
310 		case 'V':
311 			seq_puts(seq, "   vc");
312 			break;
313 		case 'D':
314 			seq_puts(seq, "   dg");
315 			break;
316 		default:
317 			seq_puts(seq, "    *");
318 			break;
319 		}
320 
321 		if (ax25_rt->digipeat != NULL)
322 			for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
323 				seq_printf(seq, " %s",
324 				     ax2asc(buf, &ax25_rt->digipeat->calls[i]));
325 
326 		seq_puts(seq, "\n");
327 	}
328 	return 0;
329 }
330 
331 const struct seq_operations ax25_rt_seqops = {
332 	.start = ax25_rt_seq_start,
333 	.next = ax25_rt_seq_next,
334 	.stop = ax25_rt_seq_stop,
335 	.show = ax25_rt_seq_show,
336 };
337 #endif
338 
339 /*
340  *	Find AX.25 route
341  *
342  *	Only routes with a reference count of zero can be destroyed.
343  *	Must be called with ax25_route_lock read locked.
344  */
ax25_get_route(ax25_address * addr,struct net_device * dev)345 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
346 {
347 	ax25_route *ax25_spe_rt = NULL;
348 	ax25_route *ax25_def_rt = NULL;
349 	ax25_route *ax25_rt;
350 
351 	/*
352 	 *	Bind to the physical interface we heard them on, or the default
353 	 *	route if none is found;
354 	 */
355 	for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
356 		if (dev == NULL) {
357 			if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
358 				ax25_spe_rt = ax25_rt;
359 			if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
360 				ax25_def_rt = ax25_rt;
361 		} else {
362 			if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
363 				ax25_spe_rt = ax25_rt;
364 			if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
365 				ax25_def_rt = ax25_rt;
366 		}
367 	}
368 
369 	ax25_rt = ax25_def_rt;
370 	if (ax25_spe_rt != NULL)
371 		ax25_rt = ax25_spe_rt;
372 
373 	return ax25_rt;
374 }
375 
376 /*
377  *	Adjust path: If you specify a default route and want to connect
378  *      a target on the digipeater path but w/o having a special route
379  *	set before, the path has to be truncated from your target on.
380  */
ax25_adjust_path(ax25_address * addr,ax25_digi * digipeat)381 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
382 {
383 	int k;
384 
385 	for (k = 0; k < digipeat->ndigi; k++) {
386 		if (ax25cmp(addr, &digipeat->calls[k]) == 0)
387 			break;
388 	}
389 
390 	digipeat->ndigi = k;
391 }
392 
393 
394 /*
395  *	Find which interface to use.
396  */
ax25_rt_autobind(ax25_cb * ax25,ax25_address * addr)397 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
398 {
399 	ax25_uid_assoc *user;
400 	ax25_route *ax25_rt;
401 	int err = 0;
402 
403 	ax25_route_lock_use();
404 	ax25_rt = ax25_get_route(addr, NULL);
405 	if (!ax25_rt) {
406 		ax25_route_lock_unuse();
407 		return -EHOSTUNREACH;
408 	}
409 	if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
410 		err = -EHOSTUNREACH;
411 		goto put;
412 	}
413 
414 	user = ax25_findbyuid(current_euid());
415 	if (user) {
416 		ax25->source_addr = user->call;
417 		ax25_uid_put(user);
418 	} else {
419 		if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
420 			err = -EPERM;
421 			goto put;
422 		}
423 		ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
424 	}
425 
426 	if (ax25_rt->digipeat != NULL) {
427 		ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
428 					 GFP_ATOMIC);
429 		if (ax25->digipeat == NULL) {
430 			err = -ENOMEM;
431 			goto put;
432 		}
433 		ax25_adjust_path(addr, ax25->digipeat);
434 	}
435 
436 	if (ax25->sk != NULL) {
437 		local_bh_disable();
438 		bh_lock_sock(ax25->sk);
439 		sock_reset_flag(ax25->sk, SOCK_ZAPPED);
440 		bh_unlock_sock(ax25->sk);
441 		local_bh_enable();
442 	}
443 
444 put:
445 	ax25_route_lock_unuse();
446 	return err;
447 }
448 
ax25_rt_build_path(struct sk_buff * skb,ax25_address * src,ax25_address * dest,ax25_digi * digi)449 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
450 	ax25_address *dest, ax25_digi *digi)
451 {
452 	unsigned char *bp;
453 	int len;
454 
455 	len = digi->ndigi * AX25_ADDR_LEN;
456 
457 	if (unlikely(skb_headroom(skb) < len)) {
458 		skb = skb_expand_head(skb, len);
459 		if (!skb) {
460 			printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
461 			return NULL;
462 		}
463 	}
464 
465 	bp = skb_push(skb, len);
466 
467 	ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
468 
469 	return skb;
470 }
471 
472 /*
473  *	Free all memory associated with routing structures.
474  */
ax25_rt_free(void)475 void __exit ax25_rt_free(void)
476 {
477 	ax25_route *s, *ax25_rt = ax25_route_list;
478 
479 	write_lock_bh(&ax25_route_lock);
480 	while (ax25_rt != NULL) {
481 		s       = ax25_rt;
482 		ax25_rt = ax25_rt->next;
483 
484 		kfree(s->digipeat);
485 		kfree(s);
486 	}
487 	write_unlock_bh(&ax25_route_lock);
488 }
489