blob: 6ab989c486f7ee66c5cd6235ce4f758fe9f277a6 [file] [log] [blame]
Steffen Klassert7e14ea12014-03-14 07:28:07 +01001/* xfrm6_protocol.c - Generic xfrm protocol multiplexer for ipv6.
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/xfrm4_protocol.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 <linux/icmpv6.h>
21#include <net/ipv6.h>
22#include <net/protocol.h>
23#include <net/xfrm.h>
24
25static struct xfrm6_protocol __rcu *esp6_handlers __read_mostly;
26static struct xfrm6_protocol __rcu *ah6_handlers __read_mostly;
27static struct xfrm6_protocol __rcu *ipcomp6_handlers __read_mostly;
28static DEFINE_MUTEX(xfrm6_protocol_mutex);
29
30static inline struct xfrm6_protocol __rcu **proto_handlers(u8 protocol)
31{
32 switch (protocol) {
33 case IPPROTO_ESP:
34 return &esp6_handlers;
35 case IPPROTO_AH:
36 return &ah6_handlers;
37 case IPPROTO_COMP:
38 return &ipcomp6_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 xfrm6_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
50{
51 int ret;
52 struct xfrm6_protocol *handler;
53
54 for_each_protocol_rcu(*proto_handlers(protocol), handler)
55 if ((ret = handler->cb_handler(skb, err)) <= 0)
56 return ret;
57
58 return 0;
59}
60EXPORT_SYMBOL(xfrm6_rcv_cb);
61
62static int xfrm6_esp_rcv(struct sk_buff *skb)
63{
64 int ret;
65 struct xfrm6_protocol *handler;
66
67 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
68
69 for_each_protocol_rcu(esp6_handlers, handler)
70 if ((ret = handler->handler(skb)) != -EINVAL)
71 return ret;
72
73 icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
74
75 kfree_skb(skb);
76 return 0;
77}
78
79static void xfrm6_esp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
80 u8 type, u8 code, int offset, __be32 info)
81{
82 struct xfrm6_protocol *handler;
83
84 for_each_protocol_rcu(esp6_handlers, handler)
85 if (!handler->err_handler(skb, opt, type, code, offset, info))
86 break;
87}
88
89static int xfrm6_ah_rcv(struct sk_buff *skb)
90{
91 int ret;
92 struct xfrm6_protocol *handler;
93
94 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
95
96 for_each_protocol_rcu(ah6_handlers, handler)
97 if ((ret = handler->handler(skb)) != -EINVAL)
98 return ret;
99
100 icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
101
102 kfree_skb(skb);
103 return 0;
104}
105
106static void xfrm6_ah_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
107 u8 type, u8 code, int offset, __be32 info)
108{
109 struct xfrm6_protocol *handler;
110
111 for_each_protocol_rcu(ah6_handlers, handler)
112 if (!handler->err_handler(skb, opt, type, code, offset, info))
113 break;
114}
115
116static int xfrm6_ipcomp_rcv(struct sk_buff *skb)
117{
118 int ret;
119 struct xfrm6_protocol *handler;
120
121 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
122
123 for_each_protocol_rcu(ipcomp6_handlers, handler)
124 if ((ret = handler->handler(skb)) != -EINVAL)
125 return ret;
126
127 icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
128
129 kfree_skb(skb);
130 return 0;
131}
132
133static void xfrm6_ipcomp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
134 u8 type, u8 code, int offset, __be32 info)
135{
136 struct xfrm6_protocol *handler;
137
138 for_each_protocol_rcu(ipcomp6_handlers, handler)
139 if (!handler->err_handler(skb, opt, type, code, offset, info))
140 break;
141}
142
143static const struct inet6_protocol esp6_protocol = {
144 .handler = xfrm6_esp_rcv,
145 .err_handler = xfrm6_esp_err,
146 .flags = INET6_PROTO_NOPOLICY,
147};
148
149static const struct inet6_protocol ah6_protocol = {
150 .handler = xfrm6_ah_rcv,
151 .err_handler = xfrm6_ah_err,
152 .flags = INET6_PROTO_NOPOLICY,
153};
154
155static const struct inet6_protocol ipcomp6_protocol = {
156 .handler = xfrm6_ipcomp_rcv,
157 .err_handler = xfrm6_ipcomp_err,
158 .flags = INET6_PROTO_NOPOLICY,
159};
160
161static struct xfrm_input_afinfo xfrm6_input_afinfo = {
162 .family = AF_INET6,
163 .owner = THIS_MODULE,
164 .callback = xfrm6_rcv_cb,
165};
166
167static inline const struct inet6_protocol *netproto(unsigned char protocol)
168{
169 switch (protocol) {
170 case IPPROTO_ESP:
171 return &esp6_protocol;
172 case IPPROTO_AH:
173 return &ah6_protocol;
174 case IPPROTO_COMP:
175 return &ipcomp6_protocol;
176 }
177
178 return NULL;
179}
180
181int xfrm6_protocol_register(struct xfrm6_protocol *handler,
182 unsigned char protocol)
183{
184 struct xfrm6_protocol __rcu **pprev;
185 struct xfrm6_protocol *t;
186 bool add_netproto = false;
187
188 int ret = -EEXIST;
189 int priority = handler->priority;
190
191 mutex_lock(&xfrm6_protocol_mutex);
192
193 if (!rcu_dereference_protected(*proto_handlers(protocol),
194 lockdep_is_held(&xfrm6_protocol_mutex)))
195 add_netproto = true;
196
197 for (pprev = proto_handlers(protocol);
198 (t = rcu_dereference_protected(*pprev,
199 lockdep_is_held(&xfrm6_protocol_mutex))) != NULL;
200 pprev = &t->next) {
201 if (t->priority < priority)
202 break;
203 if (t->priority == priority)
204 goto err;
205 }
206
207 handler->next = *pprev;
208 rcu_assign_pointer(*pprev, handler);
209
210 ret = 0;
211
212err:
213 mutex_unlock(&xfrm6_protocol_mutex);
214
215 if (add_netproto) {
216 if (inet6_add_protocol(netproto(protocol), protocol)) {
217 pr_err("%s: can't add protocol\n", __func__);
218 ret = -EAGAIN;
219 }
220 }
221
222 return ret;
223}
224EXPORT_SYMBOL(xfrm6_protocol_register);
225
226int xfrm6_protocol_deregister(struct xfrm6_protocol *handler,
227 unsigned char protocol)
228{
229 struct xfrm6_protocol __rcu **pprev;
230 struct xfrm6_protocol *t;
231 int ret = -ENOENT;
232
233 mutex_lock(&xfrm6_protocol_mutex);
234
235 for (pprev = proto_handlers(protocol);
236 (t = rcu_dereference_protected(*pprev,
237 lockdep_is_held(&xfrm6_protocol_mutex))) != NULL;
238 pprev = &t->next) {
239 if (t == handler) {
240 *pprev = handler->next;
241 ret = 0;
242 break;
243 }
244 }
245
246 if (!rcu_dereference_protected(*proto_handlers(protocol),
247 lockdep_is_held(&xfrm6_protocol_mutex))) {
248 if (inet6_del_protocol(netproto(protocol), protocol) < 0) {
249 pr_err("%s: can't remove protocol\n", __func__);
250 ret = -EAGAIN;
251 }
252 }
253
254 mutex_unlock(&xfrm6_protocol_mutex);
255
256 synchronize_net();
257
258 return ret;
259}
260EXPORT_SYMBOL(xfrm6_protocol_deregister);
261
262int __init xfrm6_protocol_init(void)
263{
264 return xfrm_input_register_afinfo(&xfrm6_input_afinfo);
265}
266
267void xfrm6_protocol_fini(void)
268{
269 xfrm_input_unregister_afinfo(&xfrm6_input_afinfo);
270}