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1/* xfrm4_protocol.c - Generic xfrm protocol multiplexer.
2 *
3 * Copyright (C) 2013 secunet Security Networks AG
4 *
5 * Author:
6 * Steffen Klassert <steffen.klassert@secunet.com>
7 *
8 * Based on:
9 * net/ipv4/tunnel4.c
10 *
11 * This program 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
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 const struct xfrm_input_afinfo xfrm4_input_afinfo = {
192 .family = AF_INET,
193 .callback = xfrm4_rcv_cb,
194};
195
196static inline const struct net_protocol *netproto(unsigned char protocol)
197{
198 switch (protocol) {
199 case IPPROTO_ESP:
200 return &esp4_protocol;
201 case IPPROTO_AH:
202 return &ah4_protocol;
203 case IPPROTO_COMP:
204 return &ipcomp4_protocol;
205 }
206
207 return NULL;
208}
209
210int xfrm4_protocol_register(struct xfrm4_protocol *handler,
211 unsigned char protocol)
212{
213 struct xfrm4_protocol __rcu **pprev;
214 struct xfrm4_protocol *t;
215 bool add_netproto = false;
216 int ret = -EEXIST;
217 int priority = handler->priority;
218
219 if (!proto_handlers(protocol) || !netproto(protocol))
220 return -EINVAL;
221
222 mutex_lock(&xfrm4_protocol_mutex);
223
224 if (!rcu_dereference_protected(*proto_handlers(protocol),
225 lockdep_is_held(&xfrm4_protocol_mutex)))
226 add_netproto = true;
227
228 for (pprev = proto_handlers(protocol);
229 (t = rcu_dereference_protected(*pprev,
230 lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
231 pprev = &t->next) {
232 if (t->priority < priority)
233 break;
234 if (t->priority == priority)
235 goto err;
236 }
237
238 handler->next = *pprev;
239 rcu_assign_pointer(*pprev, handler);
240
241 ret = 0;
242
243err:
244 mutex_unlock(&xfrm4_protocol_mutex);
245
246 if (add_netproto) {
247 if (inet_add_protocol(netproto(protocol), protocol)) {
248 pr_err("%s: can't add protocol\n", __func__);
249 ret = -EAGAIN;
250 }
251 }
252
253 return ret;
254}
255EXPORT_SYMBOL(xfrm4_protocol_register);
256
257int xfrm4_protocol_deregister(struct xfrm4_protocol *handler,
258 unsigned char protocol)
259{
260 struct xfrm4_protocol __rcu **pprev;
261 struct xfrm4_protocol *t;
262 int ret = -ENOENT;
263
264 if (!proto_handlers(protocol) || !netproto(protocol))
265 return -EINVAL;
266
267 mutex_lock(&xfrm4_protocol_mutex);
268
269 for (pprev = proto_handlers(protocol);
270 (t = rcu_dereference_protected(*pprev,
271 lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
272 pprev = &t->next) {
273 if (t == handler) {
274 *pprev = handler->next;
275 ret = 0;
276 break;
277 }
278 }
279
280 if (!rcu_dereference_protected(*proto_handlers(protocol),
281 lockdep_is_held(&xfrm4_protocol_mutex))) {
282 if (inet_del_protocol(netproto(protocol), protocol) < 0) {
283 pr_err("%s: can't remove protocol\n", __func__);
284 ret = -EAGAIN;
285 }
286 }
287
288 mutex_unlock(&xfrm4_protocol_mutex);
289
290 synchronize_net();
291
292 return ret;
293}
294EXPORT_SYMBOL(xfrm4_protocol_deregister);
295
296void __init xfrm4_protocol_init(void)
297{
298 xfrm_input_register_afinfo(&xfrm4_input_afinfo);
299}
300EXPORT_SYMBOL(xfrm4_protocol_init);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* xfrm4_protocol.c - Generic xfrm protocol multiplexer.
3 *
4 * Copyright (C) 2013 secunet Security Networks AG
5 *
6 * Author:
7 * Steffen Klassert <steffen.klassert@secunet.com>
8 *
9 * Based on:
10 * net/ipv4/tunnel4.c
11 */
12
13#include <linux/init.h>
14#include <linux/mutex.h>
15#include <linux/skbuff.h>
16#include <net/icmp.h>
17#include <net/ip.h>
18#include <net/protocol.h>
19#include <net/xfrm.h>
20
21static struct xfrm4_protocol __rcu *esp4_handlers __read_mostly;
22static struct xfrm4_protocol __rcu *ah4_handlers __read_mostly;
23static struct xfrm4_protocol __rcu *ipcomp4_handlers __read_mostly;
24static DEFINE_MUTEX(xfrm4_protocol_mutex);
25
26static inline struct xfrm4_protocol __rcu **proto_handlers(u8 protocol)
27{
28 switch (protocol) {
29 case IPPROTO_ESP:
30 return &esp4_handlers;
31 case IPPROTO_AH:
32 return &ah4_handlers;
33 case IPPROTO_COMP:
34 return &ipcomp4_handlers;
35 }
36
37 return NULL;
38}
39
40#define for_each_protocol_rcu(head, handler) \
41 for (handler = rcu_dereference(head); \
42 handler != NULL; \
43 handler = rcu_dereference(handler->next)) \
44
45static int xfrm4_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
46{
47 int ret;
48 struct xfrm4_protocol *handler;
49 struct xfrm4_protocol __rcu **head = proto_handlers(protocol);
50
51 if (!head)
52 return 0;
53
54 for_each_protocol_rcu(*head, handler)
55 if ((ret = handler->cb_handler(skb, err)) <= 0)
56 return ret;
57
58 return 0;
59}
60
61int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
62 int encap_type)
63{
64 int ret;
65 struct xfrm4_protocol *handler;
66 struct xfrm4_protocol __rcu **head = proto_handlers(nexthdr);
67
68 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
69 XFRM_SPI_SKB_CB(skb)->family = AF_INET;
70 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
71
72 if (!head)
73 goto out;
74
75 for_each_protocol_rcu(*head, handler)
76 if ((ret = handler->input_handler(skb, nexthdr, spi, encap_type)) != -EINVAL)
77 return ret;
78
79out:
80 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
81
82 kfree_skb(skb);
83 return 0;
84}
85EXPORT_SYMBOL(xfrm4_rcv_encap);
86
87static int xfrm4_esp_rcv(struct sk_buff *skb)
88{
89 int ret;
90 struct xfrm4_protocol *handler;
91
92 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
93
94 for_each_protocol_rcu(esp4_handlers, handler)
95 if ((ret = handler->handler(skb)) != -EINVAL)
96 return ret;
97
98 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
99
100 kfree_skb(skb);
101 return 0;
102}
103
104static int xfrm4_esp_err(struct sk_buff *skb, u32 info)
105{
106 struct xfrm4_protocol *handler;
107
108 for_each_protocol_rcu(esp4_handlers, handler)
109 if (!handler->err_handler(skb, info))
110 return 0;
111
112 return -ENOENT;
113}
114
115static int xfrm4_ah_rcv(struct sk_buff *skb)
116{
117 int ret;
118 struct xfrm4_protocol *handler;
119
120 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
121
122 for_each_protocol_rcu(ah4_handlers, handler)
123 if ((ret = handler->handler(skb)) != -EINVAL)
124 return ret;
125
126 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
127
128 kfree_skb(skb);
129 return 0;
130}
131
132static int xfrm4_ah_err(struct sk_buff *skb, u32 info)
133{
134 struct xfrm4_protocol *handler;
135
136 for_each_protocol_rcu(ah4_handlers, handler)
137 if (!handler->err_handler(skb, info))
138 return 0;
139
140 return -ENOENT;
141}
142
143static int xfrm4_ipcomp_rcv(struct sk_buff *skb)
144{
145 int ret;
146 struct xfrm4_protocol *handler;
147
148 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
149
150 for_each_protocol_rcu(ipcomp4_handlers, handler)
151 if ((ret = handler->handler(skb)) != -EINVAL)
152 return ret;
153
154 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
155
156 kfree_skb(skb);
157 return 0;
158}
159
160static int xfrm4_ipcomp_err(struct sk_buff *skb, u32 info)
161{
162 struct xfrm4_protocol *handler;
163
164 for_each_protocol_rcu(ipcomp4_handlers, handler)
165 if (!handler->err_handler(skb, info))
166 return 0;
167
168 return -ENOENT;
169}
170
171static const struct net_protocol esp4_protocol = {
172 .handler = xfrm4_esp_rcv,
173 .err_handler = xfrm4_esp_err,
174 .no_policy = 1,
175 .netns_ok = 1,
176};
177
178static const struct net_protocol ah4_protocol = {
179 .handler = xfrm4_ah_rcv,
180 .err_handler = xfrm4_ah_err,
181 .no_policy = 1,
182 .netns_ok = 1,
183};
184
185static const struct net_protocol ipcomp4_protocol = {
186 .handler = xfrm4_ipcomp_rcv,
187 .err_handler = xfrm4_ipcomp_err,
188 .no_policy = 1,
189 .netns_ok = 1,
190};
191
192static const struct xfrm_input_afinfo xfrm4_input_afinfo = {
193 .family = AF_INET,
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);