xref: /linux/net/ipv6/xfrm6_tunnel.c (revision b60a5b8dcf49af9f2c60ae82e0383ee8e62a9a52)
1 /*
2  * Copyright (C)2003,2004 USAGI/WIDE Project
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
16  *
17  * Authors	Mitsuru KANDA  <mk@linux-ipv6.org>
18  *		YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
19  *
20  * Based on net/ipv4/xfrm4_tunnel.c
21  *
22  */
23 #include <linux/module.h>
24 #include <linux/xfrm.h>
25 #include <linux/slab.h>
26 #include <linux/rculist.h>
27 #include <net/ip.h>
28 #include <net/xfrm.h>
29 #include <net/ipv6.h>
30 #include <linux/ipv6.h>
31 #include <linux/icmpv6.h>
32 #include <linux/mutex.h>
33 #include <net/netns/generic.h>
34 
35 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
36 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
37 
38 #define XFRM6_TUNNEL_SPI_MIN	1
39 #define XFRM6_TUNNEL_SPI_MAX	0xffffffff
40 
41 struct xfrm6_tunnel_net {
42 	struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
43 	struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
44 	u32 spi;
45 };
46 
47 static unsigned int xfrm6_tunnel_net_id __read_mostly;
48 static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
49 {
50 	return net_generic(net, xfrm6_tunnel_net_id);
51 }
52 
53 /*
54  * xfrm_tunnel_spi things are for allocating unique id ("spi")
55  * per xfrm_address_t.
56  */
57 struct xfrm6_tunnel_spi {
58 	struct hlist_node	list_byaddr;
59 	struct hlist_node	list_byspi;
60 	xfrm_address_t		addr;
61 	u32			spi;
62 	refcount_t		refcnt;
63 	struct rcu_head		rcu_head;
64 };
65 
66 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
67 
68 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
69 
70 static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
71 {
72 	unsigned int h;
73 
74 	h = ipv6_addr_hash((const struct in6_addr *)addr);
75 	h ^= h >> 16;
76 	h ^= h >> 8;
77 	h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
78 
79 	return h;
80 }
81 
82 static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
83 {
84 	return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
85 }
86 
87 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
88 {
89 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
90 	struct xfrm6_tunnel_spi *x6spi;
91 
92 	hlist_for_each_entry_rcu(x6spi,
93 			     &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
94 			     list_byaddr) {
95 		if (xfrm6_addr_equal(&x6spi->addr, saddr))
96 			return x6spi;
97 	}
98 
99 	return NULL;
100 }
101 
102 __be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
103 {
104 	struct xfrm6_tunnel_spi *x6spi;
105 	u32 spi;
106 
107 	rcu_read_lock_bh();
108 	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
109 	spi = x6spi ? x6spi->spi : 0;
110 	rcu_read_unlock_bh();
111 	return htonl(spi);
112 }
113 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
114 
115 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
116 {
117 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
118 	struct xfrm6_tunnel_spi *x6spi;
119 	int index = xfrm6_tunnel_spi_hash_byspi(spi);
120 
121 	hlist_for_each_entry(x6spi,
122 			     &xfrm6_tn->spi_byspi[index],
123 			     list_byspi) {
124 		if (x6spi->spi == spi)
125 			return -1;
126 	}
127 	return index;
128 }
129 
130 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
131 {
132 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
133 	u32 spi;
134 	struct xfrm6_tunnel_spi *x6spi;
135 	int index;
136 
137 	if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
138 	    xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
139 		xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
140 	else
141 		xfrm6_tn->spi++;
142 
143 	for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
144 		index = __xfrm6_tunnel_spi_check(net, spi);
145 		if (index >= 0)
146 			goto alloc_spi;
147 
148 		if (spi == XFRM6_TUNNEL_SPI_MAX)
149 			break;
150 	}
151 	for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
152 		index = __xfrm6_tunnel_spi_check(net, spi);
153 		if (index >= 0)
154 			goto alloc_spi;
155 	}
156 	spi = 0;
157 	goto out;
158 alloc_spi:
159 	xfrm6_tn->spi = spi;
160 	x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
161 	if (!x6spi)
162 		goto out;
163 
164 	memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
165 	x6spi->spi = spi;
166 	refcount_set(&x6spi->refcnt, 1);
167 
168 	hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
169 
170 	index = xfrm6_tunnel_spi_hash_byaddr(saddr);
171 	hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
172 out:
173 	return spi;
174 }
175 
176 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
177 {
178 	struct xfrm6_tunnel_spi *x6spi;
179 	u32 spi;
180 
181 	spin_lock_bh(&xfrm6_tunnel_spi_lock);
182 	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
183 	if (x6spi) {
184 		refcount_inc(&x6spi->refcnt);
185 		spi = x6spi->spi;
186 	} else
187 		spi = __xfrm6_tunnel_alloc_spi(net, saddr);
188 	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
189 
190 	return htonl(spi);
191 }
192 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
193 
194 static void x6spi_destroy_rcu(struct rcu_head *head)
195 {
196 	kmem_cache_free(xfrm6_tunnel_spi_kmem,
197 			container_of(head, struct xfrm6_tunnel_spi, rcu_head));
198 }
199 
200 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
201 {
202 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
203 	struct xfrm6_tunnel_spi *x6spi;
204 	struct hlist_node *n;
205 
206 	spin_lock_bh(&xfrm6_tunnel_spi_lock);
207 
208 	hlist_for_each_entry_safe(x6spi, n,
209 				  &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
210 				  list_byaddr)
211 	{
212 		if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
213 			if (refcount_dec_and_test(&x6spi->refcnt)) {
214 				hlist_del_rcu(&x6spi->list_byaddr);
215 				hlist_del_rcu(&x6spi->list_byspi);
216 				call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
217 				break;
218 			}
219 		}
220 	}
221 	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
222 }
223 
224 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
225 {
226 	skb_push(skb, -skb_network_offset(skb));
227 	return 0;
228 }
229 
230 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
231 {
232 	return skb_network_header(skb)[IP6CB(skb)->nhoff];
233 }
234 
235 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
236 {
237 	struct net *net = dev_net(skb->dev);
238 	const struct ipv6hdr *iph = ipv6_hdr(skb);
239 	__be32 spi;
240 
241 	spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
242 	return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi, NULL);
243 }
244 
245 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
246 			    u8 type, u8 code, int offset, __be32 info)
247 {
248 	/* xfrm6_tunnel native err handling */
249 	switch (type) {
250 	case ICMPV6_DEST_UNREACH:
251 		switch (code) {
252 		case ICMPV6_NOROUTE:
253 		case ICMPV6_ADM_PROHIBITED:
254 		case ICMPV6_NOT_NEIGHBOUR:
255 		case ICMPV6_ADDR_UNREACH:
256 		case ICMPV6_PORT_UNREACH:
257 		default:
258 			break;
259 		}
260 		break;
261 	case ICMPV6_PKT_TOOBIG:
262 		break;
263 	case ICMPV6_TIME_EXCEED:
264 		switch (code) {
265 		case ICMPV6_EXC_HOPLIMIT:
266 			break;
267 		case ICMPV6_EXC_FRAGTIME:
268 		default:
269 			break;
270 		}
271 		break;
272 	case ICMPV6_PARAMPROB:
273 		switch (code) {
274 		case ICMPV6_HDR_FIELD: break;
275 		case ICMPV6_UNK_NEXTHDR: break;
276 		case ICMPV6_UNK_OPTION: break;
277 		}
278 		break;
279 	default:
280 		break;
281 	}
282 
283 	return 0;
284 }
285 
286 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
287 {
288 	if (x->props.mode != XFRM_MODE_TUNNEL)
289 		return -EINVAL;
290 
291 	if (x->encap)
292 		return -EINVAL;
293 
294 	x->props.header_len = sizeof(struct ipv6hdr);
295 
296 	return 0;
297 }
298 
299 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
300 {
301 	struct net *net = xs_net(x);
302 
303 	xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
304 }
305 
306 static const struct xfrm_type xfrm6_tunnel_type = {
307 	.description	= "IP6IP6",
308 	.owner          = THIS_MODULE,
309 	.proto		= IPPROTO_IPV6,
310 	.init_state	= xfrm6_tunnel_init_state,
311 	.destructor	= xfrm6_tunnel_destroy,
312 	.input		= xfrm6_tunnel_input,
313 	.output		= xfrm6_tunnel_output,
314 };
315 
316 static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
317 	.handler	= xfrm6_tunnel_rcv,
318 	.err_handler	= xfrm6_tunnel_err,
319 	.priority	= 2,
320 };
321 
322 static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
323 	.handler	= xfrm6_tunnel_rcv,
324 	.err_handler	= xfrm6_tunnel_err,
325 	.priority	= 2,
326 };
327 
328 static int __net_init xfrm6_tunnel_net_init(struct net *net)
329 {
330 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
331 	unsigned int i;
332 
333 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
334 		INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
335 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
336 		INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
337 	xfrm6_tn->spi = 0;
338 
339 	return 0;
340 }
341 
342 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
343 {
344 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
345 	unsigned int i;
346 
347 	xfrm_flush_gc();
348 	xfrm_state_flush(net, IPSEC_PROTO_ANY, false, true);
349 
350 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
351 		WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byaddr[i]));
352 
353 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
354 		WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byspi[i]));
355 }
356 
357 static struct pernet_operations xfrm6_tunnel_net_ops = {
358 	.init	= xfrm6_tunnel_net_init,
359 	.exit	= xfrm6_tunnel_net_exit,
360 	.id	= &xfrm6_tunnel_net_id,
361 	.size	= sizeof(struct xfrm6_tunnel_net),
362 };
363 
364 static int __init xfrm6_tunnel_init(void)
365 {
366 	int rv;
367 
368 	xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
369 						  sizeof(struct xfrm6_tunnel_spi),
370 						  0, SLAB_HWCACHE_ALIGN,
371 						  NULL);
372 	if (!xfrm6_tunnel_spi_kmem)
373 		return -ENOMEM;
374 	rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
375 	if (rv < 0)
376 		goto out_pernet;
377 	rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
378 	if (rv < 0)
379 		goto out_type;
380 	rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
381 	if (rv < 0)
382 		goto out_xfrm6;
383 	rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
384 	if (rv < 0)
385 		goto out_xfrm46;
386 	return 0;
387 
388 out_xfrm46:
389 	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
390 out_xfrm6:
391 	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
392 out_type:
393 	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
394 out_pernet:
395 	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
396 	return rv;
397 }
398 
399 static void __exit xfrm6_tunnel_fini(void)
400 {
401 	xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
402 	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
403 	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
404 	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
405 	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
406 }
407 
408 module_init(xfrm6_tunnel_init);
409 module_exit(xfrm6_tunnel_fini);
410 MODULE_LICENSE("GPL");
411 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);
412