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
39static ax25_route *ax25_route_list;
40DEFINE_RWLOCK(ax25_route_lock);
41
42void 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
72static 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
145void __ax25_put_route(ax25_route *ax25_rt)
146{
147	kfree(ax25_rt->digipeat);
148	kfree(ax25_rt);
149}
150
151static 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
187static 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
223out:
224	write_unlock_bh(&ax25_route_lock);
225	ax25_dev_put(ax25_dev);
226	return err;
227}
228
229int 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
257static 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
276static 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
283static 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
289static 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
331const 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 */
345ax25_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 */
381static 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 */
397int 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
444put:
445	ax25_route_lock_unuse();
446	return err;
447}
448
449struct 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 */
475void __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