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17#include <linux/init.h>
18#include <linux/mutex.h>
19#include <linux/skbuff.h>
20#include <net/icmp.h>
21#include <net/ip.h>
22#include <net/protocol.h>
23#include <net/xfrm.h>
24
25static struct xfrm4_protocol __rcu *esp4_handlers __read_mostly;
26static struct xfrm4_protocol __rcu *ah4_handlers __read_mostly;
27static struct xfrm4_protocol __rcu *ipcomp4_handlers __read_mostly;
28static DEFINE_MUTEX(xfrm4_protocol_mutex);
29
30static inline struct xfrm4_protocol __rcu **proto_handlers(u8 protocol)
31{
32 switch (protocol) {
33 case IPPROTO_ESP:
34 return &esp4_handlers;
35 case IPPROTO_AH:
36 return &ah4_handlers;
37 case IPPROTO_COMP:
38 return &ipcomp4_handlers;
39 }
40
41 return NULL;
42}
43
44#define for_each_protocol_rcu(head, handler) \
45 for (handler = rcu_dereference(head); \
46 handler != NULL; \
47 handler = rcu_dereference(handler->next)) \
48
49int xfrm4_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
50{
51 int ret;
52 struct xfrm4_protocol *handler;
53 struct xfrm4_protocol __rcu **head = proto_handlers(protocol);
54
55 if (!head)
56 return 0;
57
58 for_each_protocol_rcu(*head, handler)
59 if ((ret = handler->cb_handler(skb, err)) <= 0)
60 return ret;
61
62 return 0;
63}
64EXPORT_SYMBOL(xfrm4_rcv_cb);
65
66int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
67 int encap_type)
68{
69 int ret;
70 struct xfrm4_protocol *handler;
71 struct xfrm4_protocol __rcu **head = proto_handlers(nexthdr);
72
73 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
74 XFRM_SPI_SKB_CB(skb)->family = AF_INET;
75 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
76
77 if (!head)
78 goto out;
79
80 for_each_protocol_rcu(*head, handler)
81 if ((ret = handler->input_handler(skb, nexthdr, spi, encap_type)) != -EINVAL)
82 return ret;
83
84out:
85 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
86
87 kfree_skb(skb);
88 return 0;
89}
90EXPORT_SYMBOL(xfrm4_rcv_encap);
91
92static int xfrm4_esp_rcv(struct sk_buff *skb)
93{
94 int ret;
95 struct xfrm4_protocol *handler;
96
97 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
98
99 for_each_protocol_rcu(esp4_handlers, handler)
100 if ((ret = handler->handler(skb)) != -EINVAL)
101 return ret;
102
103 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
104
105 kfree_skb(skb);
106 return 0;
107}
108
109static void xfrm4_esp_err(struct sk_buff *skb, u32 info)
110{
111 struct xfrm4_protocol *handler;
112
113 for_each_protocol_rcu(esp4_handlers, handler)
114 if (!handler->err_handler(skb, info))
115 break;
116}
117
118static int xfrm4_ah_rcv(struct sk_buff *skb)
119{
120 int ret;
121 struct xfrm4_protocol *handler;
122
123 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
124
125 for_each_protocol_rcu(ah4_handlers, handler)
126 if ((ret = handler->handler(skb)) != -EINVAL)
127 return ret;
128
129 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
130
131 kfree_skb(skb);
132 return 0;
133}
134
135static void xfrm4_ah_err(struct sk_buff *skb, u32 info)
136{
137 struct xfrm4_protocol *handler;
138
139 for_each_protocol_rcu(ah4_handlers, handler)
140 if (!handler->err_handler(skb, info))
141 break;
142}
143
144static int xfrm4_ipcomp_rcv(struct sk_buff *skb)
145{
146 int ret;
147 struct xfrm4_protocol *handler;
148
149 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
150
151 for_each_protocol_rcu(ipcomp4_handlers, handler)
152 if ((ret = handler->handler(skb)) != -EINVAL)
153 return ret;
154
155 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
156
157 kfree_skb(skb);
158 return 0;
159}
160
161static void xfrm4_ipcomp_err(struct sk_buff *skb, u32 info)
162{
163 struct xfrm4_protocol *handler;
164
165 for_each_protocol_rcu(ipcomp4_handlers, handler)
166 if (!handler->err_handler(skb, info))
167 break;
168}
169
170static const struct net_protocol esp4_protocol = {
171 .handler = xfrm4_esp_rcv,
172 .err_handler = xfrm4_esp_err,
173 .no_policy = 1,
174 .netns_ok = 1,
175};
176
177static const struct net_protocol ah4_protocol = {
178 .handler = xfrm4_ah_rcv,
179 .err_handler = xfrm4_ah_err,
180 .no_policy = 1,
181 .netns_ok = 1,
182};
183
184static const struct net_protocol ipcomp4_protocol = {
185 .handler = xfrm4_ipcomp_rcv,
186 .err_handler = xfrm4_ipcomp_err,
187 .no_policy = 1,
188 .netns_ok = 1,
189};
190
191static struct xfrm_input_afinfo xfrm4_input_afinfo = {
192 .family = AF_INET,
193 .owner = THIS_MODULE,
194 .callback = xfrm4_rcv_cb,
195};
196
197static inline const struct net_protocol *netproto(unsigned char protocol)
198{
199 switch (protocol) {
200 case IPPROTO_ESP:
201 return &esp4_protocol;
202 case IPPROTO_AH:
203 return &ah4_protocol;
204 case IPPROTO_COMP:
205 return &ipcomp4_protocol;
206 }
207
208 return NULL;
209}
210
211int xfrm4_protocol_register(struct xfrm4_protocol *handler,
212 unsigned char protocol)
213{
214 struct xfrm4_protocol __rcu **pprev;
215 struct xfrm4_protocol *t;
216 bool add_netproto = false;
217 int ret = -EEXIST;
218 int priority = handler->priority;
219
220 if (!proto_handlers(protocol) || !netproto(protocol))
221 return -EINVAL;
222
223 mutex_lock(&xfrm4_protocol_mutex);
224
225 if (!rcu_dereference_protected(*proto_handlers(protocol),
226 lockdep_is_held(&xfrm4_protocol_mutex)))
227 add_netproto = true;
228
229 for (pprev = proto_handlers(protocol);
230 (t = rcu_dereference_protected(*pprev,
231 lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
232 pprev = &t->next) {
233 if (t->priority < priority)
234 break;
235 if (t->priority == priority)
236 goto err;
237 }
238
239 handler->next = *pprev;
240 rcu_assign_pointer(*pprev, handler);
241
242 ret = 0;
243
244err:
245 mutex_unlock(&xfrm4_protocol_mutex);
246
247 if (add_netproto) {
248 if (inet_add_protocol(netproto(protocol), protocol)) {
249 pr_err("%s: can't add protocol\n", __func__);
250 ret = -EAGAIN;
251 }
252 }
253
254 return ret;
255}
256EXPORT_SYMBOL(xfrm4_protocol_register);
257
258int xfrm4_protocol_deregister(struct xfrm4_protocol *handler,
259 unsigned char protocol)
260{
261 struct xfrm4_protocol __rcu **pprev;
262 struct xfrm4_protocol *t;
263 int ret = -ENOENT;
264
265 if (!proto_handlers(protocol) || !netproto(protocol))
266 return -EINVAL;
267
268 mutex_lock(&xfrm4_protocol_mutex);
269
270 for (pprev = proto_handlers(protocol);
271 (t = rcu_dereference_protected(*pprev,
272 lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
273 pprev = &t->next) {
274 if (t == handler) {
275 *pprev = handler->next;
276 ret = 0;
277 break;
278 }
279 }
280
281 if (!rcu_dereference_protected(*proto_handlers(protocol),
282 lockdep_is_held(&xfrm4_protocol_mutex))) {
283 if (inet_del_protocol(netproto(protocol), protocol) < 0) {
284 pr_err("%s: can't remove protocol\n", __func__);
285 ret = -EAGAIN;
286 }
287 }
288
289 mutex_unlock(&xfrm4_protocol_mutex);
290
291 synchronize_net();
292
293 return ret;
294}
295EXPORT_SYMBOL(xfrm4_protocol_deregister);
296
297void __init xfrm4_protocol_init(void)
298{
299 xfrm_input_register_afinfo(&xfrm4_input_afinfo);
300}
301EXPORT_SYMBOL(xfrm4_protocol_init);
302
