vxlan: add necessary locking on device removal
[pandora-kernel.git] / net / x25 / x25_route.c
1 /*
2  *      X.25 Packet Layer release 002
3  *
4  *      This is ALPHA test software. This code may break your machine,
5  *      randomly fail to work with new releases, misbehave and/or generally
6  *      screw up. It might even work.
7  *
8  *      This code REQUIRES 2.1.15 or higher
9  *
10  *      This module:
11  *              This module is free software; you can redistribute it and/or
12  *              modify it under the terms of the GNU General Public License
13  *              as published by the Free Software Foundation; either version
14  *              2 of the License, or (at your option) any later version.
15  *
16  *      History
17  *      X.25 001        Jonathan Naylor Started coding.
18  */
19
20 #include <linux/if_arp.h>
21 #include <linux/init.h>
22 #include <linux/slab.h>
23 #include <net/x25.h>
24
25 LIST_HEAD(x25_route_list);
26 DEFINE_RWLOCK(x25_route_list_lock);
27
28 /*
29  *      Add a new route.
30  */
31 static int x25_add_route(struct x25_address *address, unsigned int sigdigits,
32                          struct net_device *dev)
33 {
34         struct x25_route *rt;
35         struct list_head *entry;
36         int rc = -EINVAL;
37
38         write_lock_bh(&x25_route_list_lock);
39
40         list_for_each(entry, &x25_route_list) {
41                 rt = list_entry(entry, struct x25_route, node);
42
43                 if (!memcmp(&rt->address, address, sigdigits) &&
44                     rt->sigdigits == sigdigits)
45                         goto out;
46         }
47
48         rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
49         rc = -ENOMEM;
50         if (!rt)
51                 goto out;
52
53         strcpy(rt->address.x25_addr, "000000000000000");
54         memcpy(rt->address.x25_addr, address->x25_addr, sigdigits);
55
56         rt->sigdigits = sigdigits;
57         rt->dev       = dev;
58         atomic_set(&rt->refcnt, 1);
59
60         list_add(&rt->node, &x25_route_list);
61         rc = 0;
62 out:
63         write_unlock_bh(&x25_route_list_lock);
64         return rc;
65 }
66
67 /**
68  * __x25_remove_route - remove route from x25_route_list
69  * @rt: route to remove
70  *
71  * Remove route from x25_route_list. If it was there.
72  * Caller must hold x25_route_list_lock.
73  */
74 static void __x25_remove_route(struct x25_route *rt)
75 {
76         if (rt->node.next) {
77                 list_del(&rt->node);
78                 x25_route_put(rt);
79         }
80 }
81
82 static int x25_del_route(struct x25_address *address, unsigned int sigdigits,
83                          struct net_device *dev)
84 {
85         struct x25_route *rt;
86         struct list_head *entry;
87         int rc = -EINVAL;
88
89         write_lock_bh(&x25_route_list_lock);
90
91         list_for_each(entry, &x25_route_list) {
92                 rt = list_entry(entry, struct x25_route, node);
93
94                 if (!memcmp(&rt->address, address, sigdigits) &&
95                     rt->sigdigits == sigdigits && rt->dev == dev) {
96                         __x25_remove_route(rt);
97                         rc = 0;
98                         break;
99                 }
100         }
101
102         write_unlock_bh(&x25_route_list_lock);
103         return rc;
104 }
105
106 /*
107  *      A device has been removed, remove its routes.
108  */
109 void x25_route_device_down(struct net_device *dev)
110 {
111         struct x25_route *rt;
112         struct list_head *entry, *tmp;
113
114         write_lock_bh(&x25_route_list_lock);
115
116         list_for_each_safe(entry, tmp, &x25_route_list) {
117                 rt = list_entry(entry, struct x25_route, node);
118
119                 if (rt->dev == dev)
120                         __x25_remove_route(rt);
121         }
122         write_unlock_bh(&x25_route_list_lock);
123
124         /* Remove any related forwarding */
125         x25_clear_forward_by_dev(dev);
126 }
127
128 /*
129  *      Check that the device given is a valid X.25 interface that is "up".
130  */
131 struct net_device *x25_dev_get(char *devname)
132 {
133         struct net_device *dev = dev_get_by_name(&init_net, devname);
134
135         if (dev &&
136             (!(dev->flags & IFF_UP) || (dev->type != ARPHRD_X25
137 #if IS_ENABLED(CONFIG_LLC)
138                                         && dev->type != ARPHRD_ETHER
139 #endif
140                                         ))){
141                 dev_put(dev);
142                 dev = NULL;
143         }
144
145         return dev;
146 }
147
148 /**
149  *      x25_get_route - Find a route given an X.25 address.
150  *      @addr - address to find a route for
151  *
152  *      Find a route given an X.25 address.
153  */
154 struct x25_route *x25_get_route(struct x25_address *addr)
155 {
156         struct x25_route *rt, *use = NULL;
157         struct list_head *entry;
158
159         read_lock_bh(&x25_route_list_lock);
160
161         list_for_each(entry, &x25_route_list) {
162                 rt = list_entry(entry, struct x25_route, node);
163
164                 if (!memcmp(&rt->address, addr, rt->sigdigits)) {
165                         if (!use)
166                                 use = rt;
167                         else if (rt->sigdigits > use->sigdigits)
168                                 use = rt;
169                 }
170         }
171
172         if (use)
173                 x25_route_hold(use);
174
175         read_unlock_bh(&x25_route_list_lock);
176         return use;
177 }
178
179 /*
180  *      Handle the ioctls that control the routing functions.
181  */
182 int x25_route_ioctl(unsigned int cmd, void __user *arg)
183 {
184         struct x25_route_struct rt;
185         struct net_device *dev;
186         int rc = -EINVAL;
187
188         if (cmd != SIOCADDRT && cmd != SIOCDELRT)
189                 goto out;
190
191         rc = -EFAULT;
192         if (copy_from_user(&rt, arg, sizeof(rt)))
193                 goto out;
194
195         rc = -EINVAL;
196         if (rt.sigdigits > 15)
197                 goto out;
198
199         dev = x25_dev_get(rt.device);
200         if (!dev)
201                 goto out;
202
203         if (cmd == SIOCADDRT)
204                 rc = x25_add_route(&rt.address, rt.sigdigits, dev);
205         else
206                 rc = x25_del_route(&rt.address, rt.sigdigits, dev);
207         dev_put(dev);
208 out:
209         return rc;
210 }
211
212 /*
213  *      Release all memory associated with X.25 routing structures.
214  */
215 void __exit x25_route_free(void)
216 {
217         struct x25_route *rt;
218         struct list_head *entry, *tmp;
219
220         write_lock_bh(&x25_route_list_lock);
221         list_for_each_safe(entry, tmp, &x25_route_list) {
222                 rt = list_entry(entry, struct x25_route, node);
223                 __x25_remove_route(rt);
224         }
225         write_unlock_bh(&x25_route_list_lock);
226 }