xfrm6_policy.c revision 6bb3ce25d05f2990c8a19adaf427531430267c1f 
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 <linux/err.h>
15#include <linux/kernel.h>
16#include <linux/netdevice.h>
17#include <net/addrconf.h>
18#include <net/dst.h>
19#include <net/xfrm.h>
20#include <net/ip.h>
21#include <net/ipv6.h>
22#include <net/ip6_route.h>
23#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
24#include <net/mip6.h>
25#endif
26
27static struct dst_ops xfrm6_dst_ops;
28static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
29
30static struct dst_entry *xfrm6_dst_lookup(int tos, xfrm_address_t *saddr,
31					  xfrm_address_t *daddr)
32{
33	struct flowi fl = {};
34	struct dst_entry *dst;
35	int err;
36
37	memcpy(&fl.fl6_dst, daddr, sizeof(fl.fl6_dst));
38	if (saddr)
39		memcpy(&fl.fl6_src, saddr, sizeof(fl.fl6_src));
40
41	dst = ip6_route_output(&init_net, NULL, &fl);
42
43	err = dst->error;
44	if (dst->error) {
45		dst_release(dst);
46		dst = ERR_PTR(err);
47	}
48
49	return dst;
50}
51
52static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
53{
54	struct dst_entry *dst;
55	struct net_device *dev;
56
57	dst = xfrm6_dst_lookup(0, NULL, daddr);
58	if (IS_ERR(dst))
59		return -EHOSTUNREACH;
60
61	dev = ip6_dst_idev(dst)->dev;
62	ipv6_dev_get_saddr(dev_net(dev), dev,
63			   (struct in6_addr *)&daddr->a6, 0,
64			   (struct in6_addr *)&saddr->a6);
65	dst_release(dst);
66	return 0;
67}
68
69static struct dst_entry *
70__xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
71{
72	struct dst_entry *dst;
73
74	/* Still not clear if we should set fl->fl6_{src,dst}... */
75	read_lock_bh(&policy->lock);
76	for (dst = policy->bundles; dst; dst = dst->next) {
77		struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
78		struct in6_addr fl_dst_prefix, fl_src_prefix;
79
80		ipv6_addr_prefix(&fl_dst_prefix,
81				 &fl->fl6_dst,
82				 xdst->u.rt6.rt6i_dst.plen);
83		ipv6_addr_prefix(&fl_src_prefix,
84				 &fl->fl6_src,
85				 xdst->u.rt6.rt6i_src.plen);
86		if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
87		    ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
88		    xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
89				   (xdst->u.rt6.rt6i_dst.plen != 128 ||
90				    xdst->u.rt6.rt6i_src.plen != 128))) {
91			dst_clone(dst);
92			break;
93		}
94	}
95	read_unlock_bh(&policy->lock);
96	return dst;
97}
98
99static int xfrm6_get_tos(struct flowi *fl)
100{
101	return 0;
102}
103
104static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
105			   int nfheader_len)
106{
107	if (dst->ops->family == AF_INET6) {
108		struct rt6_info *rt = (struct rt6_info*)dst;
109		if (rt->rt6i_node)
110			path->path_cookie = rt->rt6i_node->fn_sernum;
111	}
112
113	path->u.rt6.rt6i_nfheader_len = nfheader_len;
114
115	return 0;
116}
117
118static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
119{
120	struct rt6_info *rt = (struct rt6_info*)xdst->route;
121
122	xdst->u.dst.dev = dev;
123	dev_hold(dev);
124
125	xdst->u.rt6.rt6i_idev = in6_dev_get(rt->u.dst.dev);
126	if (!xdst->u.rt6.rt6i_idev)
127		return -ENODEV;
128
129	/* Sheit... I remember I did this right. Apparently,
130	 * it was magically lost, so this code needs audit */
131	xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
132						   RTF_LOCAL);
133	xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
134	xdst->u.rt6.rt6i_node = rt->rt6i_node;
135	if (rt->rt6i_node)
136		xdst->route_cookie = rt->rt6i_node->fn_sernum;
137	xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
138	xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
139	xdst->u.rt6.rt6i_src = rt->rt6i_src;
140
141	return 0;
142}
143
144static inline void
145_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
146{
147	int onlyproto = 0;
148	u16 offset = skb_network_header_len(skb);
149	struct ipv6hdr *hdr = ipv6_hdr(skb);
150	struct ipv6_opt_hdr *exthdr;
151	const unsigned char *nh = skb_network_header(skb);
152	u8 nexthdr = nh[IP6CB(skb)->nhoff];
153
154	memset(fl, 0, sizeof(struct flowi));
155	ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
156	ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
157
158	while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
159		nh = skb_network_header(skb);
160		exthdr = (struct ipv6_opt_hdr *)(nh + offset);
161
162		switch (nexthdr) {
163		case NEXTHDR_FRAGMENT:
164			onlyproto = 1;
165		case NEXTHDR_ROUTING:
166		case NEXTHDR_HOP:
167		case NEXTHDR_DEST:
168			offset += ipv6_optlen(exthdr);
169			nexthdr = exthdr->nexthdr;
170			exthdr = (struct ipv6_opt_hdr *)(nh + offset);
171			break;
172
173		case IPPROTO_UDP:
174		case IPPROTO_UDPLITE:
175		case IPPROTO_TCP:
176		case IPPROTO_SCTP:
177		case IPPROTO_DCCP:
178			if (!onlyproto && pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
179				__be16 *ports = (__be16 *)exthdr;
180
181				fl->fl_ip_sport = ports[!!reverse];
182				fl->fl_ip_dport = ports[!reverse];
183			}
184			fl->proto = nexthdr;
185			return;
186
187		case IPPROTO_ICMPV6:
188			if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
189				u8 *icmp = (u8 *)exthdr;
190
191				fl->fl_icmp_type = icmp[0];
192				fl->fl_icmp_code = icmp[1];
193			}
194			fl->proto = nexthdr;
195			return;
196
197#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
198		case IPPROTO_MH:
199			if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
200				struct ip6_mh *mh;
201				mh = (struct ip6_mh *)exthdr;
202
203				fl->fl_mh_type = mh->ip6mh_type;
204			}
205			fl->proto = nexthdr;
206			return;
207#endif
208
209		/* XXX Why are there these headers? */
210		case IPPROTO_AH:
211		case IPPROTO_ESP:
212		case IPPROTO_COMP:
213		default:
214			fl->fl_ipsec_spi = 0;
215			fl->proto = nexthdr;
216			return;
217		}
218	}
219}
220
221static inline int xfrm6_garbage_collect(struct dst_ops *ops)
222{
223	xfrm6_policy_afinfo.garbage_collect();
224	return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
225}
226
227static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
228{
229	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
230	struct dst_entry *path = xdst->route;
231
232	path->ops->update_pmtu(path, mtu);
233}
234
235static void xfrm6_dst_destroy(struct dst_entry *dst)
236{
237	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
238
239	if (likely(xdst->u.rt6.rt6i_idev))
240		in6_dev_put(xdst->u.rt6.rt6i_idev);
241	xfrm_dst_destroy(xdst);
242}
243
244static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
245			     int unregister)
246{
247	struct xfrm_dst *xdst;
248
249	if (!unregister)
250		return;
251
252	xdst = (struct xfrm_dst *)dst;
253	if (xdst->u.rt6.rt6i_idev->dev == dev) {
254		struct inet6_dev *loopback_idev =
255			in6_dev_get(dev_net(dev)->loopback_dev);
256		BUG_ON(!loopback_idev);
257
258		do {
259			in6_dev_put(xdst->u.rt6.rt6i_idev);
260			xdst->u.rt6.rt6i_idev = loopback_idev;
261			in6_dev_hold(loopback_idev);
262			xdst = (struct xfrm_dst *)xdst->u.dst.child;
263		} while (xdst->u.dst.xfrm);
264
265		__in6_dev_put(loopback_idev);
266	}
267
268	xfrm_dst_ifdown(dst, dev);
269}
270
271static struct dst_ops xfrm6_dst_ops = {
272	.family =		AF_INET6,
273	.protocol =		__constant_htons(ETH_P_IPV6),
274	.gc =			xfrm6_garbage_collect,
275	.update_pmtu =		xfrm6_update_pmtu,
276	.destroy =		xfrm6_dst_destroy,
277	.ifdown =		xfrm6_dst_ifdown,
278	.local_out =		__ip6_local_out,
279	.gc_thresh =		1024,
280	.entries =		ATOMIC_INIT(0),
281};
282
283static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
284	.family =		AF_INET6,
285	.dst_ops =		&xfrm6_dst_ops,
286	.dst_lookup =		xfrm6_dst_lookup,
287	.get_saddr = 		xfrm6_get_saddr,
288	.find_bundle =		__xfrm6_find_bundle,
289	.decode_session =	_decode_session6,
290	.get_tos =		xfrm6_get_tos,
291	.init_path =		xfrm6_init_path,
292	.fill_dst =		xfrm6_fill_dst,
293};
294
295static int __init xfrm6_policy_init(void)
296{
297	return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
298}
299
300static void xfrm6_policy_fini(void)
301{
302	xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
303}
304
305int __init xfrm6_init(void)
306{
307	int ret;
308
309	ret = xfrm6_policy_init();
310	if (ret)
311		goto out;
312
313	ret = xfrm6_state_init();
314	if (ret)
315		goto out_policy;
316out:
317	return ret;
318out_policy:
319	xfrm6_policy_fini();
320	goto out;
321}
322
323void xfrm6_fini(void)
324{
325	//xfrm6_input_fini();
326	xfrm6_policy_fini();
327	xfrm6_state_fini();
328}
329