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
41struct 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
47static int xfrm6_tunnel_net_id __read_mostly;
48static 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 */
57struct xfrm6_tunnel_spi {
58	struct hlist_node	list_byaddr;
59	struct hlist_node	list_byspi;
60	xfrm_address_t		addr;
61	u32			spi;
62	atomic_t		refcnt;
63	struct rcu_head		rcu_head;
64};
65
66static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
67
68static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
69
70static 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
82static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
83{
84	return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
85}
86
87static 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}
113EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
114
115static 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
130static 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	for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
149		index = __xfrm6_tunnel_spi_check(net, spi);
150		if (index >= 0)
151			goto alloc_spi;
152	}
153	spi = 0;
154	goto out;
155alloc_spi:
156	xfrm6_tn->spi = spi;
157	x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
158	if (!x6spi)
159		goto out;
160
161	memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
162	x6spi->spi = spi;
163	atomic_set(&x6spi->refcnt, 1);
164
165	hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
166
167	index = xfrm6_tunnel_spi_hash_byaddr(saddr);
168	hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
169out:
170	return spi;
171}
172
173__be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
174{
175	struct xfrm6_tunnel_spi *x6spi;
176	u32 spi;
177
178	spin_lock_bh(&xfrm6_tunnel_spi_lock);
179	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
180	if (x6spi) {
181		atomic_inc(&x6spi->refcnt);
182		spi = x6spi->spi;
183	} else
184		spi = __xfrm6_tunnel_alloc_spi(net, saddr);
185	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
186
187	return htonl(spi);
188}
189EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
190
191static void x6spi_destroy_rcu(struct rcu_head *head)
192{
193	kmem_cache_free(xfrm6_tunnel_spi_kmem,
194			container_of(head, struct xfrm6_tunnel_spi, rcu_head));
195}
196
197static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
198{
199	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
200	struct xfrm6_tunnel_spi *x6spi;
201	struct hlist_node *n;
202
203	spin_lock_bh(&xfrm6_tunnel_spi_lock);
204
205	hlist_for_each_entry_safe(x6spi, n,
206				  &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
207				  list_byaddr)
208	{
209		if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
210			if (atomic_dec_and_test(&x6spi->refcnt)) {
211				hlist_del_rcu(&x6spi->list_byaddr);
212				hlist_del_rcu(&x6spi->list_byspi);
213				call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
214				break;
215			}
216		}
217	}
218	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
219}
220
221static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
222{
223	skb_push(skb, -skb_network_offset(skb));
224	return 0;
225}
226
227static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
228{
229	return skb_network_header(skb)[IP6CB(skb)->nhoff];
230}
231
232static int xfrm6_tunnel_rcv(struct sk_buff *skb)
233{
234	struct net *net = dev_net(skb->dev);
235	const struct ipv6hdr *iph = ipv6_hdr(skb);
236	__be32 spi;
237
238	spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
239	return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi);
240}
241
242static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
243			    u8 type, u8 code, int offset, __be32 info)
244{
245	/* xfrm6_tunnel native err handling */
246	switch (type) {
247	case ICMPV6_DEST_UNREACH:
248		switch (code) {
249		case ICMPV6_NOROUTE:
250		case ICMPV6_ADM_PROHIBITED:
251		case ICMPV6_NOT_NEIGHBOUR:
252		case ICMPV6_ADDR_UNREACH:
253		case ICMPV6_PORT_UNREACH:
254		default:
255			break;
256		}
257		break;
258	case ICMPV6_PKT_TOOBIG:
259		break;
260	case ICMPV6_TIME_EXCEED:
261		switch (code) {
262		case ICMPV6_EXC_HOPLIMIT:
263			break;
264		case ICMPV6_EXC_FRAGTIME:
265		default:
266			break;
267		}
268		break;
269	case ICMPV6_PARAMPROB:
270		switch (code) {
271		case ICMPV6_HDR_FIELD: break;
272		case ICMPV6_UNK_NEXTHDR: break;
273		case ICMPV6_UNK_OPTION: break;
274		}
275		break;
276	default:
277		break;
278	}
279
280	return 0;
281}
282
283static int xfrm6_tunnel_init_state(struct xfrm_state *x)
284{
285	if (x->props.mode != XFRM_MODE_TUNNEL)
286		return -EINVAL;
287
288	if (x->encap)
289		return -EINVAL;
290
291	x->props.header_len = sizeof(struct ipv6hdr);
292
293	return 0;
294}
295
296static void xfrm6_tunnel_destroy(struct xfrm_state *x)
297{
298	struct net *net = xs_net(x);
299
300	xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
301}
302
303static const struct xfrm_type xfrm6_tunnel_type = {
304	.description	= "IP6IP6",
305	.owner          = THIS_MODULE,
306	.proto		= IPPROTO_IPV6,
307	.init_state	= xfrm6_tunnel_init_state,
308	.destructor	= xfrm6_tunnel_destroy,
309	.input		= xfrm6_tunnel_input,
310	.output		= xfrm6_tunnel_output,
311};
312
313static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
314	.handler	= xfrm6_tunnel_rcv,
315	.err_handler	= xfrm6_tunnel_err,
316	.priority	= 2,
317};
318
319static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
320	.handler	= xfrm6_tunnel_rcv,
321	.err_handler	= xfrm6_tunnel_err,
322	.priority	= 2,
323};
324
325static int __net_init xfrm6_tunnel_net_init(struct net *net)
326{
327	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
328	unsigned int i;
329
330	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
331		INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
332	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
333		INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
334	xfrm6_tn->spi = 0;
335
336	return 0;
337}
338
339static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
340{
341}
342
343static struct pernet_operations xfrm6_tunnel_net_ops = {
344	.init	= xfrm6_tunnel_net_init,
345	.exit	= xfrm6_tunnel_net_exit,
346	.id	= &xfrm6_tunnel_net_id,
347	.size	= sizeof(struct xfrm6_tunnel_net),
348};
349
350static int __init xfrm6_tunnel_init(void)
351{
352	int rv;
353
354	xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
355						  sizeof(struct xfrm6_tunnel_spi),
356						  0, SLAB_HWCACHE_ALIGN,
357						  NULL);
358	if (!xfrm6_tunnel_spi_kmem)
359		return -ENOMEM;
360	rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
361	if (rv < 0)
362		goto out_pernet;
363	rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
364	if (rv < 0)
365		goto out_type;
366	rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
367	if (rv < 0)
368		goto out_xfrm6;
369	rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
370	if (rv < 0)
371		goto out_xfrm46;
372	return 0;
373
374out_xfrm46:
375	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
376out_xfrm6:
377	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
378out_type:
379	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
380out_pernet:
381	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
382	return rv;
383}
384
385static void __exit xfrm6_tunnel_fini(void)
386{
387	xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
388	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
389	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
390	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
391	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
392}
393
394module_init(xfrm6_tunnel_init);
395module_exit(xfrm6_tunnel_fini);
396MODULE_LICENSE("GPL");
397MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);
398