xref: /openbmc/linux/net/ipv6/xfrm6_tunnel.c (revision 4800cd83)
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, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17  *
18  * Authors	Mitsuru KANDA  <mk@linux-ipv6.org>
19  * 		YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
20  *
21  * Based on net/ipv4/xfrm4_tunnel.c
22  *
23  */
24 #include <linux/module.h>
25 #include <linux/xfrm.h>
26 #include <linux/slab.h>
27 #include <linux/rculist.h>
28 #include <net/ip.h>
29 #include <net/xfrm.h>
30 #include <net/ipv6.h>
31 #include <linux/ipv6.h>
32 #include <linux/icmpv6.h>
33 #include <linux/mutex.h>
34 #include <net/netns/generic.h>
35 
36 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
37 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
38 
39 #define XFRM6_TUNNEL_SPI_MIN	1
40 #define XFRM6_TUNNEL_SPI_MAX	0xffffffff
41 
42 struct xfrm6_tunnel_net {
43 	struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
44 	struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
45 	u32 spi;
46 };
47 
48 static int xfrm6_tunnel_net_id __read_mostly;
49 static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
50 {
51 	return net_generic(net, xfrm6_tunnel_net_id);
52 }
53 
54 /*
55  * xfrm_tunnel_spi things are for allocating unique id ("spi")
56  * per xfrm_address_t.
57  */
58 struct xfrm6_tunnel_spi {
59 	struct hlist_node	list_byaddr;
60 	struct hlist_node	list_byspi;
61 	xfrm_address_t		addr;
62 	u32			spi;
63 	atomic_t		refcnt;
64 	struct rcu_head		rcu_head;
65 };
66 
67 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
68 
69 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
70 
71 static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
72 {
73 	unsigned h;
74 
75 	h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
76 	h ^= h >> 16;
77 	h ^= h >> 8;
78 	h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
79 
80 	return h;
81 }
82 
83 static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
84 {
85 	return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
86 }
87 
88 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr)
89 {
90 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
91 	struct xfrm6_tunnel_spi *x6spi;
92 	struct hlist_node *pos;
93 
94 	hlist_for_each_entry_rcu(x6spi, pos,
95 			     &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
96 			     list_byaddr) {
97 		if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
98 			return x6spi;
99 	}
100 
101 	return NULL;
102 }
103 
104 __be32 xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr)
105 {
106 	struct xfrm6_tunnel_spi *x6spi;
107 	u32 spi;
108 
109 	rcu_read_lock_bh();
110 	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
111 	spi = x6spi ? x6spi->spi : 0;
112 	rcu_read_unlock_bh();
113 	return htonl(spi);
114 }
115 
116 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
117 
118 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
119 {
120 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
121 	struct xfrm6_tunnel_spi *x6spi;
122 	int index = xfrm6_tunnel_spi_hash_byspi(spi);
123 	struct hlist_node *pos;
124 
125 	hlist_for_each_entry(x6spi, pos,
126 			     &xfrm6_tn->spi_byspi[index],
127 			     list_byspi) {
128 		if (x6spi->spi == spi)
129 			return -1;
130 	}
131 	return index;
132 }
133 
134 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
135 {
136 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
137 	u32 spi;
138 	struct xfrm6_tunnel_spi *x6spi;
139 	int index;
140 
141 	if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
142 	    xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
143 		xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
144 	else
145 		xfrm6_tn->spi++;
146 
147 	for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
148 		index = __xfrm6_tunnel_spi_check(net, spi);
149 		if (index >= 0)
150 			goto alloc_spi;
151 	}
152 	for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
153 		index = __xfrm6_tunnel_spi_check(net, spi);
154 		if (index >= 0)
155 			goto alloc_spi;
156 	}
157 	spi = 0;
158 	goto out;
159 alloc_spi:
160 	xfrm6_tn->spi = spi;
161 	x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
162 	if (!x6spi)
163 		goto out;
164 
165 	memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
166 	x6spi->spi = spi;
167 	atomic_set(&x6spi->refcnt, 1);
168 
169 	hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
170 
171 	index = xfrm6_tunnel_spi_hash_byaddr(saddr);
172 	hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
173 out:
174 	return spi;
175 }
176 
177 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
178 {
179 	struct xfrm6_tunnel_spi *x6spi;
180 	u32 spi;
181 
182 	spin_lock_bh(&xfrm6_tunnel_spi_lock);
183 	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
184 	if (x6spi) {
185 		atomic_inc(&x6spi->refcnt);
186 		spi = x6spi->spi;
187 	} else
188 		spi = __xfrm6_tunnel_alloc_spi(net, saddr);
189 	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
190 
191 	return htonl(spi);
192 }
193 
194 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
195 
196 static void x6spi_destroy_rcu(struct rcu_head *head)
197 {
198 	kmem_cache_free(xfrm6_tunnel_spi_kmem,
199 			container_of(head, struct xfrm6_tunnel_spi, rcu_head));
200 }
201 
202 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
203 {
204 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
205 	struct xfrm6_tunnel_spi *x6spi;
206 	struct hlist_node *pos, *n;
207 
208 	spin_lock_bh(&xfrm6_tunnel_spi_lock);
209 
210 	hlist_for_each_entry_safe(x6spi, pos, n,
211 				  &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
212 				  list_byaddr)
213 	{
214 		if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
215 			if (atomic_dec_and_test(&x6spi->refcnt)) {
216 				hlist_del_rcu(&x6spi->list_byaddr);
217 				hlist_del_rcu(&x6spi->list_byspi);
218 				call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
219 				break;
220 			}
221 		}
222 	}
223 	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
224 }
225 
226 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
227 {
228 	skb_push(skb, -skb_network_offset(skb));
229 	return 0;
230 }
231 
232 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
233 {
234 	return skb_network_header(skb)[IP6CB(skb)->nhoff];
235 }
236 
237 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
238 {
239 	struct net *net = dev_net(skb->dev);
240 	struct ipv6hdr *iph = ipv6_hdr(skb);
241 	__be32 spi;
242 
243 	spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&iph->saddr);
244 	return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
245 }
246 
247 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
248 			    u8 type, u8 code, int offset, __be32 info)
249 {
250 	/* xfrm6_tunnel native err handling */
251 	switch (type) {
252 	case ICMPV6_DEST_UNREACH:
253 		switch (code) {
254 		case ICMPV6_NOROUTE:
255 		case ICMPV6_ADM_PROHIBITED:
256 		case ICMPV6_NOT_NEIGHBOUR:
257 		case ICMPV6_ADDR_UNREACH:
258 		case ICMPV6_PORT_UNREACH:
259 		default:
260 			break;
261 		}
262 		break;
263 	case ICMPV6_PKT_TOOBIG:
264 		break;
265 	case ICMPV6_TIME_EXCEED:
266 		switch (code) {
267 		case ICMPV6_EXC_HOPLIMIT:
268 			break;
269 		case ICMPV6_EXC_FRAGTIME:
270 		default:
271 			break;
272 		}
273 		break;
274 	case ICMPV6_PARAMPROB:
275 		switch (code) {
276 		case ICMPV6_HDR_FIELD: break;
277 		case ICMPV6_UNK_NEXTHDR: break;
278 		case ICMPV6_UNK_OPTION: break;
279 		}
280 		break;
281 	default:
282 		break;
283 	}
284 
285 	return 0;
286 }
287 
288 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
289 {
290 	if (x->props.mode != XFRM_MODE_TUNNEL)
291 		return -EINVAL;
292 
293 	if (x->encap)
294 		return -EINVAL;
295 
296 	x->props.header_len = sizeof(struct ipv6hdr);
297 
298 	return 0;
299 }
300 
301 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
302 {
303 	struct net *net = xs_net(x);
304 
305 	xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
306 }
307 
308 static const struct xfrm_type xfrm6_tunnel_type = {
309 	.description	= "IP6IP6",
310 	.owner          = THIS_MODULE,
311 	.proto		= IPPROTO_IPV6,
312 	.init_state	= xfrm6_tunnel_init_state,
313 	.destructor	= xfrm6_tunnel_destroy,
314 	.input		= xfrm6_tunnel_input,
315 	.output		= xfrm6_tunnel_output,
316 };
317 
318 static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
319 	.handler	= xfrm6_tunnel_rcv,
320 	.err_handler	= xfrm6_tunnel_err,
321 	.priority	= 2,
322 };
323 
324 static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
325 	.handler	= xfrm6_tunnel_rcv,
326 	.err_handler	= xfrm6_tunnel_err,
327 	.priority	= 2,
328 };
329 
330 static int __net_init xfrm6_tunnel_net_init(struct net *net)
331 {
332 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
333 	unsigned int i;
334 
335 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
336 		INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
337 	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
338 		INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
339 	xfrm6_tn->spi = 0;
340 
341 	return 0;
342 }
343 
344 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
345 {
346 }
347 
348 static struct pernet_operations xfrm6_tunnel_net_ops = {
349 	.init	= xfrm6_tunnel_net_init,
350 	.exit	= xfrm6_tunnel_net_exit,
351 	.id	= &xfrm6_tunnel_net_id,
352 	.size	= sizeof(struct xfrm6_tunnel_net),
353 };
354 
355 static int __init xfrm6_tunnel_init(void)
356 {
357 	int rv;
358 
359 	xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
360 						  sizeof(struct xfrm6_tunnel_spi),
361 						  0, SLAB_HWCACHE_ALIGN,
362 						  NULL);
363 	if (!xfrm6_tunnel_spi_kmem)
364 		return -ENOMEM;
365 	rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
366 	if (rv < 0)
367 		goto out_pernet;
368 	rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
369 	if (rv < 0)
370 		goto out_type;
371 	rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
372 	if (rv < 0)
373 		goto out_xfrm6;
374 	rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
375 	if (rv < 0)
376 		goto out_xfrm46;
377 	return 0;
378 
379 out_xfrm46:
380 	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
381 out_xfrm6:
382 	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
383 out_type:
384 	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
385 out_pernet:
386 	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
387 	return rv;
388 }
389 
390 static void __exit xfrm6_tunnel_fini(void)
391 {
392 	xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
393 	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
394 	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
395 	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
396 	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
397 }
398 
399 module_init(xfrm6_tunnel_init);
400 module_exit(xfrm6_tunnel_fini);
401 MODULE_LICENSE("GPL");
402 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);
403