1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *	X.25 Packet Layer release 002
4 *
5 *	This is ALPHA test software. This code may break your machine,
6 *	randomly fail to work with new releases, misbehave and/or generally
7 *	screw up. It might even work.
8 *
9 *	This code REQUIRES 2.1.15 or higher
10 *
11 *	History
12 *	X.25 001	Jonathan Naylor	Started coding.
13 */
14
15#include <linux/if_arp.h>
16#include <linux/init.h>
17#include <linux/slab.h>
18#include <net/x25.h>
19
20LIST_HEAD(x25_route_list);
21DEFINE_RWLOCK(x25_route_list_lock);
22
23/*
24 *	Add a new route.
25 */
26static int x25_add_route(struct x25_address *address, unsigned int sigdigits,
27			 struct net_device *dev)
28{
29	struct x25_route *rt;
30	int rc = -EINVAL;
31
32	write_lock_bh(&x25_route_list_lock);
33
34	list_for_each_entry(rt, &x25_route_list, node) {
35		if (!memcmp(&rt->address, address, sigdigits) &&
36		    rt->sigdigits == sigdigits)
37			goto out;
38	}
39
40	rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
41	rc = -ENOMEM;
42	if (!rt)
43		goto out;
44
45	strcpy(rt->address.x25_addr, "000000000000000");
46	memcpy(rt->address.x25_addr, address->x25_addr, sigdigits);
47
48	rt->sigdigits = sigdigits;
49	rt->dev       = dev;
50	refcount_set(&rt->refcnt, 1);
51
52	list_add(&rt->node, &x25_route_list);
53	rc = 0;
54out:
55	write_unlock_bh(&x25_route_list_lock);
56	return rc;
57}
58
59/**
60 * __x25_remove_route - remove route from x25_route_list
61 * @rt: route to remove
62 *
63 * Remove route from x25_route_list. If it was there.
64 * Caller must hold x25_route_list_lock.
65 */
66static void __x25_remove_route(struct x25_route *rt)
67{
68	if (rt->node.next) {
69		list_del(&rt->node);
70		x25_route_put(rt);
71	}
72}
73
74static int x25_del_route(struct x25_address *address, unsigned int sigdigits,
75			 struct net_device *dev)
76{
77	struct x25_route *rt;
78	int rc = -EINVAL;
79
80	write_lock_bh(&x25_route_list_lock);
81
82	list_for_each_entry(rt, &x25_route_list, node) {
83		if (!memcmp(&rt->address, address, sigdigits) &&
84		    rt->sigdigits == sigdigits && rt->dev == dev) {
85			__x25_remove_route(rt);
86			rc = 0;
87			break;
88		}
89	}
90
91	write_unlock_bh(&x25_route_list_lock);
92	return rc;
93}
94
95/*
96 *	A device has been removed, remove its routes.
97 */
98void x25_route_device_down(struct net_device *dev)
99{
100	struct x25_route *rt;
101	struct list_head *entry, *tmp;
102
103	write_lock_bh(&x25_route_list_lock);
104
105	list_for_each_safe(entry, tmp, &x25_route_list) {
106		rt = list_entry(entry, struct x25_route, node);
107
108		if (rt->dev == dev)
109			__x25_remove_route(rt);
110	}
111	write_unlock_bh(&x25_route_list_lock);
112}
113
114/*
115 *	Check that the device given is a valid X.25 interface that is "up".
116 */
117struct net_device *x25_dev_get(char *devname)
118{
119	struct net_device *dev = dev_get_by_name(&init_net, devname);
120
121	if (dev && (!(dev->flags & IFF_UP) || dev->type != ARPHRD_X25)) {
122		dev_put(dev);
123		dev = NULL;
124	}
125
126	return dev;
127}
128
129/**
130 * 	x25_get_route -	Find a route given an X.25 address.
131 *	@addr: - address to find a route for
132 *
133 * 	Find a route given an X.25 address.
134 */
135struct x25_route *x25_get_route(struct x25_address *addr)
136{
137	struct x25_route *rt, *use = NULL;
138
139	read_lock_bh(&x25_route_list_lock);
140
141	list_for_each_entry(rt, &x25_route_list, node) {
142		if (!memcmp(&rt->address, addr, rt->sigdigits)) {
143			if (!use)
144				use = rt;
145			else if (rt->sigdigits > use->sigdigits)
146				use = rt;
147		}
148	}
149
150	if (use)
151		x25_route_hold(use);
152
153	read_unlock_bh(&x25_route_list_lock);
154	return use;
155}
156
157/*
158 *	Handle the ioctls that control the routing functions.
159 */
160int x25_route_ioctl(unsigned int cmd, void __user *arg)
161{
162	struct x25_route_struct rt;
163	struct net_device *dev;
164	int rc = -EINVAL;
165
166	if (cmd != SIOCADDRT && cmd != SIOCDELRT)
167		goto out;
168
169	rc = -EFAULT;
170	if (copy_from_user(&rt, arg, sizeof(rt)))
171		goto out;
172
173	rc = -EINVAL;
174	if (rt.sigdigits > 15)
175		goto out;
176
177	dev = x25_dev_get(rt.device);
178	if (!dev)
179		goto out;
180
181	if (cmd == SIOCADDRT)
182		rc = x25_add_route(&rt.address, rt.sigdigits, dev);
183	else
184		rc = x25_del_route(&rt.address, rt.sigdigits, dev);
185	dev_put(dev);
186out:
187	return rc;
188}
189
190/*
191 *	Release all memory associated with X.25 routing structures.
192 */
193void __exit x25_route_free(void)
194{
195	struct x25_route *rt;
196	struct list_head *entry, *tmp;
197
198	write_lock_bh(&x25_route_list_lock);
199	list_for_each_safe(entry, tmp, &x25_route_list) {
200		rt = list_entry(entry, struct x25_route, node);
201		__x25_remove_route(rt);
202	}
203	write_unlock_bh(&x25_route_list_lock);
204}
205