xfrm6_policy.c revision 92d63decc0b6a5d600f792fcf5f3ff9718c09a3d 
1/*
2 * xfrm6_policy.c: based on xfrm4_policy.c
3 *
4 * Authors:
5 *	Mitsuru KANDA @USAGI
6 * 	Kazunori MIYAZAWA @USAGI
7 * 	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
8 * 		IPv6 support
9 * 	YOSHIFUJI Hideaki
10 * 		Split up af-specific portion
11 *
12 */
13
14#include <asm/bug.h>
15#include <linux/compiler.h>
16#include <linux/config.h>
17#include <linux/netdevice.h>
18#include <net/addrconf.h>
19#include <net/xfrm.h>
20#include <net/ip.h>
21#include <net/ipv6.h>
22#include <net/ip6_route.h>
23
24static struct dst_ops xfrm6_dst_ops;
25static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
26
27static struct xfrm_type_map xfrm6_type_map = { .lock = RW_LOCK_UNLOCKED };
28
29static int xfrm6_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
30{
31	int err = 0;
32	*dst = (struct xfrm_dst*)ip6_route_output(NULL, fl);
33	if (!*dst)
34		err = -ENETUNREACH;
35	return err;
36}
37
38static struct dst_entry *
39__xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
40{
41	struct dst_entry *dst;
42
43	/* Still not clear if we should set fl->fl6_{src,dst}... */
44	read_lock_bh(&policy->lock);
45	for (dst = policy->bundles; dst; dst = dst->next) {
46		struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
47		struct in6_addr fl_dst_prefix, fl_src_prefix;
48
49		ipv6_addr_prefix(&fl_dst_prefix,
50				 &fl->fl6_dst,
51				 xdst->u.rt6.rt6i_dst.plen);
52		ipv6_addr_prefix(&fl_src_prefix,
53				 &fl->fl6_src,
54				 xdst->u.rt6.rt6i_src.plen);
55		if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
56		    ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
57		    xfrm_bundle_ok(xdst, fl, AF_INET6)) {
58			dst_clone(dst);
59			break;
60		}
61	}
62	read_unlock_bh(&policy->lock);
63	return dst;
64}
65
66/* Allocate chain of dst_entry's, attach known xfrm's, calculate
67 * all the metrics... Shortly, bundle a bundle.
68 */
69
70static int
71__xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
72		      struct flowi *fl, struct dst_entry **dst_p)
73{
74	struct dst_entry *dst, *dst_prev;
75	struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
76	struct rt6_info *rt  = rt0;
77	struct in6_addr *remote = &fl->fl6_dst;
78	struct in6_addr *local  = &fl->fl6_src;
79	struct flowi fl_tunnel = {
80		.nl_u = {
81			.ip6_u = {
82				.saddr = *local,
83				.daddr = *remote
84			}
85		}
86	};
87	int i;
88	int err = 0;
89	int header_len = 0;
90	int trailer_len = 0;
91
92	dst = dst_prev = NULL;
93	dst_hold(&rt->u.dst);
94
95	for (i = 0; i < nx; i++) {
96		struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
97		struct xfrm_dst *xdst;
98		int tunnel = 0;
99
100		if (unlikely(dst1 == NULL)) {
101			err = -ENOBUFS;
102			dst_release(&rt->u.dst);
103			goto error;
104		}
105
106		if (!dst)
107			dst = dst1;
108		else {
109			dst_prev->child = dst1;
110			dst1->flags |= DST_NOHASH;
111			dst_clone(dst1);
112		}
113
114		xdst = (struct xfrm_dst *)dst1;
115		xdst->route = &rt->u.dst;
116		if (rt->rt6i_node)
117			xdst->route_cookie = rt->rt6i_node->fn_sernum;
118
119		dst1->next = dst_prev;
120		dst_prev = dst1;
121		if (xfrm[i]->props.mode) {
122			remote = (struct in6_addr*)&xfrm[i]->id.daddr;
123			local  = (struct in6_addr*)&xfrm[i]->props.saddr;
124			tunnel = 1;
125		}
126		header_len += xfrm[i]->props.header_len;
127		trailer_len += xfrm[i]->props.trailer_len;
128
129		if (tunnel) {
130			ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
131			ipv6_addr_copy(&fl_tunnel.fl6_src, local);
132			err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
133					      &fl_tunnel, AF_INET6);
134			if (err)
135				goto error;
136		} else
137			dst_hold(&rt->u.dst);
138	}
139
140	dst_prev->child = &rt->u.dst;
141	dst->path = &rt->u.dst;
142	if (rt->rt6i_node)
143		((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
144
145	*dst_p = dst;
146	dst = dst_prev;
147
148	dst_prev = *dst_p;
149	i = 0;
150	for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
151		struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
152
153		dst_prev->xfrm = xfrm[i++];
154		dst_prev->dev = rt->u.dst.dev;
155		if (rt->u.dst.dev)
156			dev_hold(rt->u.dst.dev);
157		dst_prev->obsolete	= -1;
158		dst_prev->flags	       |= DST_HOST;
159		dst_prev->lastuse	= jiffies;
160		dst_prev->header_len	= header_len;
161		dst_prev->trailer_len	= trailer_len;
162		memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
163
164		/* Copy neighbour for reachability confirmation */
165		dst_prev->neighbour	= neigh_clone(rt->u.dst.neighbour);
166		dst_prev->input		= rt->u.dst.input;
167		dst_prev->output	= xfrm6_output;
168		/* Sheit... I remember I did this right. Apparently,
169		 * it was magically lost, so this code needs audit */
170		x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
171		x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
172		x->u.rt6.rt6i_node     = rt0->rt6i_node;
173		x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
174		memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
175		x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
176		x->u.rt6.rt6i_src      = rt0->rt6i_src;
177		x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
178		in6_dev_hold(rt0->rt6i_idev);
179		header_len -= x->u.dst.xfrm->props.header_len;
180		trailer_len -= x->u.dst.xfrm->props.trailer_len;
181	}
182
183	xfrm_init_pmtu(dst);
184	return 0;
185
186error:
187	if (dst)
188		dst_free(dst);
189	return err;
190}
191
192static inline void
193_decode_session6(struct sk_buff *skb, struct flowi *fl)
194{
195	u16 offset = sizeof(struct ipv6hdr);
196	struct ipv6hdr *hdr = skb->nh.ipv6h;
197	struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
198	u8 nexthdr = skb->nh.ipv6h->nexthdr;
199
200	memset(fl, 0, sizeof(struct flowi));
201	ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
202	ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
203
204	while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
205		switch (nexthdr) {
206		case NEXTHDR_ROUTING:
207		case NEXTHDR_HOP:
208		case NEXTHDR_DEST:
209			offset += ipv6_optlen(exthdr);
210			nexthdr = exthdr->nexthdr;
211			exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
212			break;
213
214		case IPPROTO_UDP:
215		case IPPROTO_TCP:
216		case IPPROTO_SCTP:
217			if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
218				u16 *ports = (u16 *)exthdr;
219
220				fl->fl_ip_sport = ports[0];
221				fl->fl_ip_dport = ports[1];
222			}
223			fl->proto = nexthdr;
224			return;
225
226		case IPPROTO_ICMPV6:
227			if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
228				u8 *icmp = (u8 *)exthdr;
229
230				fl->fl_icmp_type = icmp[0];
231				fl->fl_icmp_code = icmp[1];
232			}
233			fl->proto = nexthdr;
234			return;
235
236		/* XXX Why are there these headers? */
237		case IPPROTO_AH:
238		case IPPROTO_ESP:
239		case IPPROTO_COMP:
240		default:
241			fl->fl_ipsec_spi = 0;
242			fl->proto = nexthdr;
243			return;
244		};
245	}
246}
247
248static inline int xfrm6_garbage_collect(void)
249{
250	read_lock(&xfrm6_policy_afinfo.lock);
251	xfrm6_policy_afinfo.garbage_collect();
252	read_unlock(&xfrm6_policy_afinfo.lock);
253	return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
254}
255
256static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
257{
258	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
259	struct dst_entry *path = xdst->route;
260
261	path->ops->update_pmtu(path, mtu);
262}
263
264static void xfrm6_dst_destroy(struct dst_entry *dst)
265{
266	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
267
268	if (likely(xdst->u.rt6.rt6i_idev))
269		in6_dev_put(xdst->u.rt6.rt6i_idev);
270	xfrm_dst_destroy(xdst);
271}
272
273static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
274			     int unregister)
275{
276	struct xfrm_dst *xdst;
277
278	if (!unregister)
279		return;
280
281	xdst = (struct xfrm_dst *)dst;
282	if (xdst->u.rt6.rt6i_idev->dev == dev) {
283		struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
284		BUG_ON(!loopback_idev);
285
286		do {
287			in6_dev_put(xdst->u.rt6.rt6i_idev);
288			xdst->u.rt6.rt6i_idev = loopback_idev;
289			in6_dev_hold(loopback_idev);
290			xdst = (struct xfrm_dst *)xdst->u.dst.child;
291		} while (xdst->u.dst.xfrm);
292
293		__in6_dev_put(loopback_idev);
294	}
295
296	xfrm_dst_ifdown(dst, dev);
297}
298
299static struct dst_ops xfrm6_dst_ops = {
300	.family =		AF_INET6,
301	.protocol =		__constant_htons(ETH_P_IPV6),
302	.gc =			xfrm6_garbage_collect,
303	.update_pmtu =		xfrm6_update_pmtu,
304	.destroy =		xfrm6_dst_destroy,
305	.ifdown =		xfrm6_dst_ifdown,
306	.gc_thresh =		1024,
307	.entry_size =		sizeof(struct xfrm_dst),
308};
309
310static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
311	.family =		AF_INET6,
312	.lock = 		RW_LOCK_UNLOCKED,
313	.type_map = 		&xfrm6_type_map,
314	.dst_ops =		&xfrm6_dst_ops,
315	.dst_lookup =		xfrm6_dst_lookup,
316	.find_bundle =		__xfrm6_find_bundle,
317	.bundle_create =	__xfrm6_bundle_create,
318	.decode_session =	_decode_session6,
319};
320
321static void __init xfrm6_policy_init(void)
322{
323	xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
324}
325
326static void xfrm6_policy_fini(void)
327{
328	xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
329}
330
331void __init xfrm6_init(void)
332{
333	xfrm6_policy_init();
334	xfrm6_state_init();
335}
336
337void xfrm6_fini(void)
338{
339	//xfrm6_input_fini();
340	xfrm6_policy_fini();
341	xfrm6_state_fini();
342}
343