xfrm6_policy.c revision 59cae0092e4da753b5a2adb32933e0d1b223bcc5 
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(struct net *net, int tos,
31					  xfrm_address_t *saddr,
32					  xfrm_address_t *daddr)
33{
34	struct flowi fl = {};
35	struct dst_entry *dst;
36	int err;
37
38	memcpy(&fl.fl6_dst, daddr, sizeof(fl.fl6_dst));
39	if (saddr)
40		memcpy(&fl.fl6_src, saddr, sizeof(fl.fl6_src));
41
42	dst = ip6_route_output(net, NULL, &fl);
43
44	err = dst->error;
45	if (dst->error) {
46		dst_release(dst);
47		dst = ERR_PTR(err);
48	}
49
50	return dst;
51}
52
53static int xfrm6_get_saddr(struct net *net,
54			   xfrm_address_t *saddr, xfrm_address_t *daddr)
55{
56	struct dst_entry *dst;
57	struct net_device *dev;
58
59	dst = xfrm6_dst_lookup(net, 0, NULL, daddr);
60	if (IS_ERR(dst))
61		return -EHOSTUNREACH;
62
63	dev = ip6_dst_idev(dst)->dev;
64	ipv6_dev_get_saddr(dev_net(dev), dev,
65			   (struct in6_addr *)&daddr->a6, 0,
66			   (struct in6_addr *)&saddr->a6);
67	dst_release(dst);
68	return 0;
69}
70
71static struct dst_entry *
72__xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
73{
74	struct dst_entry *dst;
75
76	/* Still not clear if we should set fl->fl6_{src,dst}... */
77	read_lock_bh(&policy->lock);
78	for (dst = policy->bundles; dst; dst = dst->next) {
79		struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
80		struct in6_addr fl_dst_prefix, fl_src_prefix;
81
82		ipv6_addr_prefix(&fl_dst_prefix,
83				 &fl->fl6_dst,
84				 xdst->u.rt6.rt6i_dst.plen);
85		ipv6_addr_prefix(&fl_src_prefix,
86				 &fl->fl6_src,
87				 xdst->u.rt6.rt6i_src.plen);
88		if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
89		    ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
90		    xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
91				   (xdst->u.rt6.rt6i_dst.plen != 128 ||
92				    xdst->u.rt6.rt6i_src.plen != 128))) {
93			dst_clone(dst);
94			break;
95		}
96	}
97	read_unlock_bh(&policy->lock);
98	return dst;
99}
100
101static int xfrm6_get_tos(struct flowi *fl)
102{
103	return 0;
104}
105
106static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
107			   int nfheader_len)
108{
109	if (dst->ops->family == AF_INET6) {
110		struct rt6_info *rt = (struct rt6_info*)dst;
111		if (rt->rt6i_node)
112			path->path_cookie = rt->rt6i_node->fn_sernum;
113	}
114
115	path->u.rt6.rt6i_nfheader_len = nfheader_len;
116
117	return 0;
118}
119
120static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
121{
122	struct rt6_info *rt = (struct rt6_info*)xdst->route;
123
124	xdst->u.dst.dev = dev;
125	dev_hold(dev);
126
127	xdst->u.rt6.rt6i_idev = in6_dev_get(rt->u.dst.dev);
128	if (!xdst->u.rt6.rt6i_idev)
129		return -ENODEV;
130
131	/* Sheit... I remember I did this right. Apparently,
132	 * it was magically lost, so this code needs audit */
133	xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
134						   RTF_LOCAL);
135	xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
136	xdst->u.rt6.rt6i_node = rt->rt6i_node;
137	if (rt->rt6i_node)
138		xdst->route_cookie = rt->rt6i_node->fn_sernum;
139	xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
140	xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
141	xdst->u.rt6.rt6i_src = rt->rt6i_src;
142
143	return 0;
144}
145
146static inline void
147_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
148{
149	int onlyproto = 0;
150	u16 offset = skb_network_header_len(skb);
151	struct ipv6hdr *hdr = ipv6_hdr(skb);
152	struct ipv6_opt_hdr *exthdr;
153	const unsigned char *nh = skb_network_header(skb);
154	u8 nexthdr = nh[IP6CB(skb)->nhoff];
155
156	memset(fl, 0, sizeof(struct flowi));
157	ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
158	ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
159
160	while (nh + offset + 1 < skb->data ||
161	       pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
162		nh = skb_network_header(skb);
163		exthdr = (struct ipv6_opt_hdr *)(nh + offset);
164
165		switch (nexthdr) {
166		case NEXTHDR_FRAGMENT:
167			onlyproto = 1;
168		case NEXTHDR_ROUTING:
169		case NEXTHDR_HOP:
170		case NEXTHDR_DEST:
171			offset += ipv6_optlen(exthdr);
172			nexthdr = exthdr->nexthdr;
173			exthdr = (struct ipv6_opt_hdr *)(nh + offset);
174			break;
175
176		case IPPROTO_UDP:
177		case IPPROTO_UDPLITE:
178		case IPPROTO_TCP:
179		case IPPROTO_SCTP:
180		case IPPROTO_DCCP:
181			if (!onlyproto && (nh + offset + 4 < skb->data ||
182			     pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
183				__be16 *ports = (__be16 *)exthdr;
184
185				fl->fl_ip_sport = ports[!!reverse];
186				fl->fl_ip_dport = ports[!reverse];
187			}
188			fl->proto = nexthdr;
189			return;
190
191		case IPPROTO_ICMPV6:
192			if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
193				u8 *icmp = (u8 *)exthdr;
194
195				fl->fl_icmp_type = icmp[0];
196				fl->fl_icmp_code = icmp[1];
197			}
198			fl->proto = nexthdr;
199			return;
200
201#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
202		case IPPROTO_MH:
203			if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
204				struct ip6_mh *mh;
205				mh = (struct ip6_mh *)exthdr;
206
207				fl->fl_mh_type = mh->ip6mh_type;
208			}
209			fl->proto = nexthdr;
210			return;
211#endif
212
213		/* XXX Why are there these headers? */
214		case IPPROTO_AH:
215		case IPPROTO_ESP:
216		case IPPROTO_COMP:
217		default:
218			fl->fl_ipsec_spi = 0;
219			fl->proto = nexthdr;
220			return;
221		}
222	}
223}
224
225static inline int xfrm6_garbage_collect(struct dst_ops *ops)
226{
227	xfrm6_policy_afinfo.garbage_collect(&init_net);
228	return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
229}
230
231static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
232{
233	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
234	struct dst_entry *path = xdst->route;
235
236	path->ops->update_pmtu(path, mtu);
237}
238
239static void xfrm6_dst_destroy(struct dst_entry *dst)
240{
241	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
242
243	if (likely(xdst->u.rt6.rt6i_idev))
244		in6_dev_put(xdst->u.rt6.rt6i_idev);
245	xfrm_dst_destroy(xdst);
246}
247
248static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
249			     int unregister)
250{
251	struct xfrm_dst *xdst;
252
253	if (!unregister)
254		return;
255
256	xdst = (struct xfrm_dst *)dst;
257	if (xdst->u.rt6.rt6i_idev->dev == dev) {
258		struct inet6_dev *loopback_idev =
259			in6_dev_get(dev_net(dev)->loopback_dev);
260		BUG_ON(!loopback_idev);
261
262		do {
263			in6_dev_put(xdst->u.rt6.rt6i_idev);
264			xdst->u.rt6.rt6i_idev = loopback_idev;
265			in6_dev_hold(loopback_idev);
266			xdst = (struct xfrm_dst *)xdst->u.dst.child;
267		} while (xdst->u.dst.xfrm);
268
269		__in6_dev_put(loopback_idev);
270	}
271
272	xfrm_dst_ifdown(dst, dev);
273}
274
275static struct dst_ops xfrm6_dst_ops = {
276	.family =		AF_INET6,
277	.protocol =		cpu_to_be16(ETH_P_IPV6),
278	.gc =			xfrm6_garbage_collect,
279	.update_pmtu =		xfrm6_update_pmtu,
280	.destroy =		xfrm6_dst_destroy,
281	.ifdown =		xfrm6_dst_ifdown,
282	.local_out =		__ip6_local_out,
283	.gc_thresh =		1024,
284	.entries =		ATOMIC_INIT(0),
285};
286
287static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
288	.family =		AF_INET6,
289	.dst_ops =		&xfrm6_dst_ops,
290	.dst_lookup =		xfrm6_dst_lookup,
291	.get_saddr = 		xfrm6_get_saddr,
292	.find_bundle =		__xfrm6_find_bundle,
293	.decode_session =	_decode_session6,
294	.get_tos =		xfrm6_get_tos,
295	.init_path =		xfrm6_init_path,
296	.fill_dst =		xfrm6_fill_dst,
297};
298
299static int __init xfrm6_policy_init(void)
300{
301	return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
302}
303
304static void xfrm6_policy_fini(void)
305{
306	xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
307}
308
309int __init xfrm6_init(void)
310{
311	int ret;
312
313	ret = xfrm6_policy_init();
314	if (ret)
315		goto out;
316
317	ret = xfrm6_state_init();
318	if (ret)
319		goto out_policy;
320out:
321	return ret;
322out_policy:
323	xfrm6_policy_fini();
324	goto out;
325}
326
327void xfrm6_fini(void)
328{
329	//xfrm6_input_fini();
330	xfrm6_policy_fini();
331	xfrm6_state_fini();
332}
333