GNU Linux-libre 4.19.211-gnu1
[releases.git] / net / ipv4 / tunnel4.c
1 /* tunnel4.c: Generic IP tunnel transformer.
2  *
3  * Copyright (C) 2003 David S. Miller (davem@redhat.com)
4  */
5
6 #include <linux/init.h>
7 #include <linux/module.h>
8 #include <linux/mutex.h>
9 #include <linux/mpls.h>
10 #include <linux/netdevice.h>
11 #include <linux/skbuff.h>
12 #include <linux/slab.h>
13 #include <net/icmp.h>
14 #include <net/ip.h>
15 #include <net/protocol.h>
16 #include <net/xfrm.h>
17
18 static struct xfrm_tunnel __rcu *tunnel4_handlers __read_mostly;
19 static struct xfrm_tunnel __rcu *tunnel64_handlers __read_mostly;
20 static struct xfrm_tunnel __rcu *tunnelmpls4_handlers __read_mostly;
21 static DEFINE_MUTEX(tunnel4_mutex);
22
23 static inline struct xfrm_tunnel __rcu **fam_handlers(unsigned short family)
24 {
25         return (family == AF_INET) ? &tunnel4_handlers :
26                 (family == AF_INET6) ? &tunnel64_handlers :
27                 &tunnelmpls4_handlers;
28 }
29
30 int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
31 {
32         struct xfrm_tunnel __rcu **pprev;
33         struct xfrm_tunnel *t;
34
35         int ret = -EEXIST;
36         int priority = handler->priority;
37
38         mutex_lock(&tunnel4_mutex);
39
40         for (pprev = fam_handlers(family);
41              (t = rcu_dereference_protected(*pprev,
42                         lockdep_is_held(&tunnel4_mutex))) != NULL;
43              pprev = &t->next) {
44                 if (t->priority > priority)
45                         break;
46                 if (t->priority == priority)
47                         goto err;
48         }
49
50         handler->next = *pprev;
51         rcu_assign_pointer(*pprev, handler);
52
53         ret = 0;
54
55 err:
56         mutex_unlock(&tunnel4_mutex);
57
58         return ret;
59 }
60 EXPORT_SYMBOL(xfrm4_tunnel_register);
61
62 int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
63 {
64         struct xfrm_tunnel __rcu **pprev;
65         struct xfrm_tunnel *t;
66         int ret = -ENOENT;
67
68         mutex_lock(&tunnel4_mutex);
69
70         for (pprev = fam_handlers(family);
71              (t = rcu_dereference_protected(*pprev,
72                         lockdep_is_held(&tunnel4_mutex))) != NULL;
73              pprev = &t->next) {
74                 if (t == handler) {
75                         *pprev = handler->next;
76                         ret = 0;
77                         break;
78                 }
79         }
80
81         mutex_unlock(&tunnel4_mutex);
82
83         synchronize_net();
84
85         return ret;
86 }
87 EXPORT_SYMBOL(xfrm4_tunnel_deregister);
88
89 #define for_each_tunnel_rcu(head, handler)              \
90         for (handler = rcu_dereference(head);           \
91              handler != NULL;                           \
92              handler = rcu_dereference(handler->next))  \
93
94 static int tunnel4_rcv(struct sk_buff *skb)
95 {
96         struct xfrm_tunnel *handler;
97
98         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
99                 goto drop;
100
101         for_each_tunnel_rcu(tunnel4_handlers, handler)
102                 if (!handler->handler(skb))
103                         return 0;
104
105         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
106
107 drop:
108         kfree_skb(skb);
109         return 0;
110 }
111
112 #if IS_ENABLED(CONFIG_IPV6)
113 static int tunnel64_rcv(struct sk_buff *skb)
114 {
115         struct xfrm_tunnel *handler;
116
117         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
118                 goto drop;
119
120         for_each_tunnel_rcu(tunnel64_handlers, handler)
121                 if (!handler->handler(skb))
122                         return 0;
123
124         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
125
126 drop:
127         kfree_skb(skb);
128         return 0;
129 }
130 #endif
131
132 #if IS_ENABLED(CONFIG_MPLS)
133 static int tunnelmpls4_rcv(struct sk_buff *skb)
134 {
135         struct xfrm_tunnel *handler;
136
137         if (!pskb_may_pull(skb, sizeof(struct mpls_label)))
138                 goto drop;
139
140         for_each_tunnel_rcu(tunnelmpls4_handlers, handler)
141                 if (!handler->handler(skb))
142                         return 0;
143
144         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
145
146 drop:
147         kfree_skb(skb);
148         return 0;
149 }
150 #endif
151
152 static void tunnel4_err(struct sk_buff *skb, u32 info)
153 {
154         struct xfrm_tunnel *handler;
155
156         for_each_tunnel_rcu(tunnel4_handlers, handler)
157                 if (!handler->err_handler(skb, info))
158                         break;
159 }
160
161 #if IS_ENABLED(CONFIG_IPV6)
162 static void tunnel64_err(struct sk_buff *skb, u32 info)
163 {
164         struct xfrm_tunnel *handler;
165
166         for_each_tunnel_rcu(tunnel64_handlers, handler)
167                 if (!handler->err_handler(skb, info))
168                         break;
169 }
170 #endif
171
172 #if IS_ENABLED(CONFIG_MPLS)
173 static void tunnelmpls4_err(struct sk_buff *skb, u32 info)
174 {
175         struct xfrm_tunnel *handler;
176
177         for_each_tunnel_rcu(tunnelmpls4_handlers, handler)
178                 if (!handler->err_handler(skb, info))
179                         break;
180 }
181 #endif
182
183 static const struct net_protocol tunnel4_protocol = {
184         .handler        =       tunnel4_rcv,
185         .err_handler    =       tunnel4_err,
186         .no_policy      =       1,
187         .netns_ok       =       1,
188 };
189
190 #if IS_ENABLED(CONFIG_IPV6)
191 static const struct net_protocol tunnel64_protocol = {
192         .handler        =       tunnel64_rcv,
193         .err_handler    =       tunnel64_err,
194         .no_policy      =       1,
195         .netns_ok       =       1,
196 };
197 #endif
198
199 #if IS_ENABLED(CONFIG_MPLS)
200 static const struct net_protocol tunnelmpls4_protocol = {
201         .handler        =       tunnelmpls4_rcv,
202         .err_handler    =       tunnelmpls4_err,
203         .no_policy      =       1,
204         .netns_ok       =       1,
205 };
206 #endif
207
208 static int __init tunnel4_init(void)
209 {
210         if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP))
211                 goto err;
212 #if IS_ENABLED(CONFIG_IPV6)
213         if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
214                 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
215                 goto err;
216         }
217 #endif
218 #if IS_ENABLED(CONFIG_MPLS)
219         if (inet_add_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS)) {
220                 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
221 #if IS_ENABLED(CONFIG_IPV6)
222                 inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6);
223 #endif
224                 goto err;
225         }
226 #endif
227         return 0;
228
229 err:
230         pr_err("%s: can't add protocol\n", __func__);
231         return -EAGAIN;
232 }
233
234 static void __exit tunnel4_fini(void)
235 {
236 #if IS_ENABLED(CONFIG_MPLS)
237         if (inet_del_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS))
238                 pr_err("tunnelmpls4 close: can't remove protocol\n");
239 #endif
240 #if IS_ENABLED(CONFIG_IPV6)
241         if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
242                 pr_err("tunnel64 close: can't remove protocol\n");
243 #endif
244         if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
245                 pr_err("tunnel4 close: can't remove protocol\n");
246 }
247
248 module_init(tunnel4_init);
249 module_exit(tunnel4_fini);
250 MODULE_LICENSE("GPL");