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6#include <linux/init.h>
7#include <linux/module.h>
8#include <linux/mutex.h>
9#include <linux/netdevice.h>
10#include <linux/skbuff.h>
11#include <linux/slab.h>
12#include <net/icmp.h>
13#include <net/ip.h>
14#include <net/protocol.h>
15#include <net/xfrm.h>
16
17static struct xfrm_tunnel __rcu *tunnel4_handlers __read_mostly;
18static struct xfrm_tunnel __rcu *tunnel64_handlers __read_mostly;
19static DEFINE_MUTEX(tunnel4_mutex);
20
21static inline struct xfrm_tunnel __rcu **fam_handlers(unsigned short family)
22{
23 return (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
24}
25
26int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
27{
28 struct xfrm_tunnel __rcu **pprev;
29 struct xfrm_tunnel *t;
30
31 int ret = -EEXIST;
32 int priority = handler->priority;
33
34 mutex_lock(&tunnel4_mutex);
35
36 for (pprev = fam_handlers(family);
37 (t = rcu_dereference_protected(*pprev,
38 lockdep_is_held(&tunnel4_mutex))) != NULL;
39 pprev = &t->next) {
40 if (t->priority > priority)
41 break;
42 if (t->priority == priority)
43 goto err;
44 }
45
46 handler->next = *pprev;
47 rcu_assign_pointer(*pprev, handler);
48
49 ret = 0;
50
51err:
52 mutex_unlock(&tunnel4_mutex);
53
54 return ret;
55}
56EXPORT_SYMBOL(xfrm4_tunnel_register);
57
58int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
59{
60 struct xfrm_tunnel __rcu **pprev;
61 struct xfrm_tunnel *t;
62 int ret = -ENOENT;
63
64 mutex_lock(&tunnel4_mutex);
65
66 for (pprev = fam_handlers(family);
67 (t = rcu_dereference_protected(*pprev,
68 lockdep_is_held(&tunnel4_mutex))) != NULL;
69 pprev = &t->next) {
70 if (t == handler) {
71 *pprev = handler->next;
72 ret = 0;
73 break;
74 }
75 }
76
77 mutex_unlock(&tunnel4_mutex);
78
79 synchronize_net();
80
81 return ret;
82}
83EXPORT_SYMBOL(xfrm4_tunnel_deregister);
84
85#define for_each_tunnel_rcu(head, handler) \
86 for (handler = rcu_dereference(head); \
87 handler != NULL; \
88 handler = rcu_dereference(handler->next)) \
89
90static int tunnel4_rcv(struct sk_buff *skb)
91{
92 struct xfrm_tunnel *handler;
93
94 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
95 goto drop;
96
97 for_each_tunnel_rcu(tunnel4_handlers, handler)
98 if (!handler->handler(skb))
99 return 0;
100
101 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
102
103drop:
104 kfree_skb(skb);
105 return 0;
106}
107
108#if IS_ENABLED(CONFIG_IPV6)
109static int tunnel64_rcv(struct sk_buff *skb)
110{
111 struct xfrm_tunnel *handler;
112
113 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
114 goto drop;
115
116 for_each_tunnel_rcu(tunnel64_handlers, handler)
117 if (!handler->handler(skb))
118 return 0;
119
120 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
121
122drop:
123 kfree_skb(skb);
124 return 0;
125}
126#endif
127
128static void tunnel4_err(struct sk_buff *skb, u32 info)
129{
130 struct xfrm_tunnel *handler;
131
132 for_each_tunnel_rcu(tunnel4_handlers, handler)
133 if (!handler->err_handler(skb, info))
134 break;
135}
136
137#if IS_ENABLED(CONFIG_IPV6)
138static void tunnel64_err(struct sk_buff *skb, u32 info)
139{
140 struct xfrm_tunnel *handler;
141
142 for_each_tunnel_rcu(tunnel64_handlers, handler)
143 if (!handler->err_handler(skb, info))
144 break;
145}
146#endif
147
148static const struct net_protocol tunnel4_protocol = {
149 .handler = tunnel4_rcv,
150 .err_handler = tunnel4_err,
151 .no_policy = 1,
152 .netns_ok = 1,
153};
154
155#if IS_ENABLED(CONFIG_IPV6)
156static const struct net_protocol tunnel64_protocol = {
157 .handler = tunnel64_rcv,
158 .err_handler = tunnel64_err,
159 .no_policy = 1,
160 .netns_ok = 1,
161};
162#endif
163
164static int __init tunnel4_init(void)
165{
166 if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
167 pr_err("%s: can't add protocol\n", __func__);
168 return -EAGAIN;
169 }
170#if IS_ENABLED(CONFIG_IPV6)
171 if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
172 pr_err("tunnel64 init: can't add protocol\n");
173 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
174 return -EAGAIN;
175 }
176#endif
177 return 0;
178}
179
180static void __exit tunnel4_fini(void)
181{
182#if IS_ENABLED(CONFIG_IPV6)
183 if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
184 pr_err("tunnel64 close: can't remove protocol\n");
185#endif
186 if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
187 pr_err("tunnel4 close: can't remove protocol\n");
188}
189
190module_init(tunnel4_init);
191module_exit(tunnel4_fini);
192MODULE_LICENSE("GPL");
193
