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/list.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
34/*
35 * xfrm_tunnel_spi things are for allocating unique id ("spi")
36 * per xfrm_address_t.
37 */
38struct xfrm6_tunnel_spi {
39	struct hlist_node list_byaddr;
40	struct hlist_node list_byspi;
41	xfrm_address_t addr;
42	u32 spi;
43	atomic_t refcnt;
44};
45
46static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);
47
48static u32 xfrm6_tunnel_spi;
49
50#define XFRM6_TUNNEL_SPI_MIN	1
51#define XFRM6_TUNNEL_SPI_MAX	0xffffffff
52
53static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
54
55#define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
56#define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
57
58static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
59static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
60
61static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
62{
63	unsigned h;
64
65	h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
66	h ^= h >> 16;
67	h ^= h >> 8;
68	h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
69
70	return h;
71}
72
73static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
74{
75	return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
76}
77
78
79static int xfrm6_tunnel_spi_init(void)
80{
81	int i;
82
83	xfrm6_tunnel_spi = 0;
84	xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
85						  sizeof(struct xfrm6_tunnel_spi),
86						  0, SLAB_HWCACHE_ALIGN,
87						  NULL, NULL);
88	if (!xfrm6_tunnel_spi_kmem)
89		return -ENOMEM;
90
91	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
92		INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
93	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
94		INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
95	return 0;
96}
97
98static void xfrm6_tunnel_spi_fini(void)
99{
100	int i;
101
102	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
103		if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
104			return;
105	}
106	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
107		if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
108			return;
109	}
110	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
111	xfrm6_tunnel_spi_kmem = NULL;
112}
113
114static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
115{
116	struct xfrm6_tunnel_spi *x6spi;
117	struct hlist_node *pos;
118
119	hlist_for_each_entry(x6spi, pos,
120			     &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
121			     list_byaddr) {
122		if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
123			return x6spi;
124	}
125
126	return NULL;
127}
128
129__be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
130{
131	struct xfrm6_tunnel_spi *x6spi;
132	u32 spi;
133
134	read_lock_bh(&xfrm6_tunnel_spi_lock);
135	x6spi = __xfrm6_tunnel_spi_lookup(saddr);
136	spi = x6spi ? x6spi->spi : 0;
137	read_unlock_bh(&xfrm6_tunnel_spi_lock);
138	return htonl(spi);
139}
140
141EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
142
143static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
144{
145	u32 spi;
146	struct xfrm6_tunnel_spi *x6spi;
147	struct hlist_node *pos;
148	unsigned index;
149
150	if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
151	    xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
152		xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
153	else
154		xfrm6_tunnel_spi++;
155
156	for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
157		index = xfrm6_tunnel_spi_hash_byspi(spi);
158		hlist_for_each_entry(x6spi, pos,
159				     &xfrm6_tunnel_spi_byspi[index],
160				     list_byspi) {
161			if (x6spi->spi == spi)
162				goto try_next_1;
163		}
164		xfrm6_tunnel_spi = spi;
165		goto alloc_spi;
166try_next_1:;
167	}
168	for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
169		index = xfrm6_tunnel_spi_hash_byspi(spi);
170		hlist_for_each_entry(x6spi, pos,
171				     &xfrm6_tunnel_spi_byspi[index],
172				     list_byspi) {
173			if (x6spi->spi == spi)
174				goto try_next_2;
175		}
176		xfrm6_tunnel_spi = spi;
177		goto alloc_spi;
178try_next_2:;
179	}
180	spi = 0;
181	goto out;
182alloc_spi:
183	x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
184	if (!x6spi)
185		goto out;
186
187	memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
188	x6spi->spi = spi;
189	atomic_set(&x6spi->refcnt, 1);
190
191	hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
192
193	index = xfrm6_tunnel_spi_hash_byaddr(saddr);
194	hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
195out:
196	return spi;
197}
198
199__be32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
200{
201	struct xfrm6_tunnel_spi *x6spi;
202	u32 spi;
203
204	write_lock_bh(&xfrm6_tunnel_spi_lock);
205	x6spi = __xfrm6_tunnel_spi_lookup(saddr);
206	if (x6spi) {
207		atomic_inc(&x6spi->refcnt);
208		spi = x6spi->spi;
209	} else
210		spi = __xfrm6_tunnel_alloc_spi(saddr);
211	write_unlock_bh(&xfrm6_tunnel_spi_lock);
212
213	return htonl(spi);
214}
215
216EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
217
218void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
219{
220	struct xfrm6_tunnel_spi *x6spi;
221	struct hlist_node *pos, *n;
222
223	write_lock_bh(&xfrm6_tunnel_spi_lock);
224
225	hlist_for_each_entry_safe(x6spi, pos, n,
226				  &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
227				  list_byaddr)
228	{
229		if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
230			if (atomic_dec_and_test(&x6spi->refcnt)) {
231				hlist_del(&x6spi->list_byaddr);
232				hlist_del(&x6spi->list_byspi);
233				kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
234				break;
235			}
236		}
237	}
238	write_unlock_bh(&xfrm6_tunnel_spi_lock);
239}
240
241EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
242
243static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
244{
245	struct ipv6hdr *top_iph;
246
247	top_iph = (struct ipv6hdr *)skb->data;
248	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
249
250	return 0;
251}
252
253static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
254{
255	return 0;
256}
257
258static int xfrm6_tunnel_rcv(struct sk_buff *skb)
259{
260	struct ipv6hdr *iph = ipv6_hdr(skb);
261	__be32 spi;
262
263	spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
264	return xfrm6_rcv_spi(skb, spi) > 0 ? : 0;
265}
266
267static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
268			    int type, int code, int offset, __be32 info)
269{
270	/* xfrm6_tunnel native err handling */
271	switch (type) {
272	case ICMPV6_DEST_UNREACH:
273		switch (code) {
274		case ICMPV6_NOROUTE:
275		case ICMPV6_ADM_PROHIBITED:
276		case ICMPV6_NOT_NEIGHBOUR:
277		case ICMPV6_ADDR_UNREACH:
278		case ICMPV6_PORT_UNREACH:
279		default:
280			break;
281		}
282		break;
283	case ICMPV6_PKT_TOOBIG:
284		break;
285	case ICMPV6_TIME_EXCEED:
286		switch (code) {
287		case ICMPV6_EXC_HOPLIMIT:
288			break;
289		case ICMPV6_EXC_FRAGTIME:
290		default:
291			break;
292		}
293		break;
294	case ICMPV6_PARAMPROB:
295		switch (code) {
296		case ICMPV6_HDR_FIELD: break;
297		case ICMPV6_UNK_NEXTHDR: break;
298		case ICMPV6_UNK_OPTION: break;
299		}
300		break;
301	default:
302		break;
303	}
304
305	return 0;
306}
307
308static int xfrm6_tunnel_init_state(struct xfrm_state *x)
309{
310	if (x->props.mode != XFRM_MODE_TUNNEL)
311		return -EINVAL;
312
313	if (x->encap)
314		return -EINVAL;
315
316	x->props.header_len = sizeof(struct ipv6hdr);
317
318	return 0;
319}
320
321static void xfrm6_tunnel_destroy(struct xfrm_state *x)
322{
323	xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
324}
325
326static struct xfrm_type xfrm6_tunnel_type = {
327	.description	= "IP6IP6",
328	.owner          = THIS_MODULE,
329	.proto		= IPPROTO_IPV6,
330	.init_state	= xfrm6_tunnel_init_state,
331	.destructor	= xfrm6_tunnel_destroy,
332	.input		= xfrm6_tunnel_input,
333	.output		= xfrm6_tunnel_output,
334};
335
336static struct xfrm6_tunnel xfrm6_tunnel_handler = {
337	.handler	= xfrm6_tunnel_rcv,
338	.err_handler	= xfrm6_tunnel_err,
339	.priority	= 2,
340};
341
342static struct xfrm6_tunnel xfrm46_tunnel_handler = {
343	.handler	= xfrm6_tunnel_rcv,
344	.err_handler	= xfrm6_tunnel_err,
345	.priority	= 2,
346};
347
348static int __init xfrm6_tunnel_init(void)
349{
350	if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0)
351		return -EAGAIN;
352
353	if (xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6)) {
354		xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
355		return -EAGAIN;
356	}
357	if (xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET)) {
358		xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
359		xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
360		return -EAGAIN;
361	}
362	if (xfrm6_tunnel_spi_init() < 0) {
363		xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
364		xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
365		xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
366		return -EAGAIN;
367	}
368	return 0;
369}
370
371static void __exit xfrm6_tunnel_fini(void)
372{
373	xfrm6_tunnel_spi_fini();
374	xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
375	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
376	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
377}
378
379module_init(xfrm6_tunnel_init);
380module_exit(xfrm6_tunnel_fini);
381MODULE_LICENSE("GPL");
382