xfrm6_policy.c revision 05d8402576c9c1b85bfc9e4f9d6a21c27ccbd5b1 
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 xfrm_policy_afinfo xfrm6_policy_afinfo;
28
29static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos,
30					  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(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(struct net *net,
53			   xfrm_address_t *saddr, xfrm_address_t *daddr)
54{
55	struct dst_entry *dst;
56	struct net_device *dev;
57
58	dst = xfrm6_dst_lookup(net, 0, NULL, daddr);
59	if (IS_ERR(dst))
60		return -EHOSTUNREACH;
61
62	dev = ip6_dst_idev(dst)->dev;
63	ipv6_dev_get_saddr(dev_net(dev), dev,
64			   (struct in6_addr *)&daddr->a6, 0,
65			   (struct in6_addr *)&saddr->a6);
66	dst_release(dst);
67	return 0;
68}
69
70static int xfrm6_get_tos(const struct flowi *fl)
71{
72	return 0;
73}
74
75static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
76			   int nfheader_len)
77{
78	if (dst->ops->family == AF_INET6) {
79		struct rt6_info *rt = (struct rt6_info*)dst;
80		if (rt->rt6i_node)
81			path->path_cookie = rt->rt6i_node->fn_sernum;
82	}
83
84	path->u.rt6.rt6i_nfheader_len = nfheader_len;
85
86	return 0;
87}
88
89static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
90			  struct flowi *fl)
91{
92	struct rt6_info *rt = (struct rt6_info*)xdst->route;
93
94	xdst->u.dst.dev = dev;
95	dev_hold(dev);
96
97	xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
98	if (!xdst->u.rt6.rt6i_idev)
99		return -ENODEV;
100
101	xdst->u.rt6.rt6i_peer = rt->rt6i_peer;
102	if (rt->rt6i_peer)
103		atomic_inc(&rt->rt6i_peer->refcnt);
104
105	/* Sheit... I remember I did this right. Apparently,
106	 * it was magically lost, so this code needs audit */
107	xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
108						   RTF_LOCAL);
109	xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
110	xdst->u.rt6.rt6i_node = rt->rt6i_node;
111	if (rt->rt6i_node)
112		xdst->route_cookie = rt->rt6i_node->fn_sernum;
113	xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
114	xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
115	xdst->u.rt6.rt6i_src = rt->rt6i_src;
116
117	return 0;
118}
119
120static inline void
121_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
122{
123	int onlyproto = 0;
124	u16 offset = skb_network_header_len(skb);
125	struct ipv6hdr *hdr = ipv6_hdr(skb);
126	struct ipv6_opt_hdr *exthdr;
127	const unsigned char *nh = skb_network_header(skb);
128	u8 nexthdr = nh[IP6CB(skb)->nhoff];
129
130	memset(fl, 0, sizeof(struct flowi));
131	fl->mark = skb->mark;
132
133	ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
134	ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
135
136	while (nh + offset + 1 < skb->data ||
137	       pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
138		nh = skb_network_header(skb);
139		exthdr = (struct ipv6_opt_hdr *)(nh + offset);
140
141		switch (nexthdr) {
142		case NEXTHDR_FRAGMENT:
143			onlyproto = 1;
144		case NEXTHDR_ROUTING:
145		case NEXTHDR_HOP:
146		case NEXTHDR_DEST:
147			offset += ipv6_optlen(exthdr);
148			nexthdr = exthdr->nexthdr;
149			exthdr = (struct ipv6_opt_hdr *)(nh + offset);
150			break;
151
152		case IPPROTO_UDP:
153		case IPPROTO_UDPLITE:
154		case IPPROTO_TCP:
155		case IPPROTO_SCTP:
156		case IPPROTO_DCCP:
157			if (!onlyproto && (nh + offset + 4 < skb->data ||
158			     pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
159				__be16 *ports = (__be16 *)exthdr;
160
161				fl->fl_ip_sport = ports[!!reverse];
162				fl->fl_ip_dport = ports[!reverse];
163			}
164			fl->proto = nexthdr;
165			return;
166
167		case IPPROTO_ICMPV6:
168			if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
169				u8 *icmp = (u8 *)exthdr;
170
171				fl->fl_icmp_type = icmp[0];
172				fl->fl_icmp_code = icmp[1];
173			}
174			fl->proto = nexthdr;
175			return;
176
177#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
178		case IPPROTO_MH:
179			if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
180				struct ip6_mh *mh;
181				mh = (struct ip6_mh *)exthdr;
182
183				fl->fl_mh_type = mh->ip6mh_type;
184			}
185			fl->proto = nexthdr;
186			return;
187#endif
188
189		/* XXX Why are there these headers? */
190		case IPPROTO_AH:
191		case IPPROTO_ESP:
192		case IPPROTO_COMP:
193		default:
194			fl->fl_ipsec_spi = 0;
195			fl->proto = nexthdr;
196			return;
197		}
198	}
199}
200
201static inline int xfrm6_garbage_collect(struct dst_ops *ops)
202{
203	struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
204
205	xfrm6_policy_afinfo.garbage_collect(net);
206	return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
207}
208
209static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
210{
211	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
212	struct dst_entry *path = xdst->route;
213
214	path->ops->update_pmtu(path, mtu);
215}
216
217static void xfrm6_dst_destroy(struct dst_entry *dst)
218{
219	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
220
221	if (likely(xdst->u.rt6.rt6i_idev))
222		in6_dev_put(xdst->u.rt6.rt6i_idev);
223	dst_destroy_metrics_generic(dst);
224	if (likely(xdst->u.rt6.rt6i_peer))
225		inet_putpeer(xdst->u.rt6.rt6i_peer);
226	xfrm_dst_destroy(xdst);
227}
228
229static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
230			     int unregister)
231{
232	struct xfrm_dst *xdst;
233
234	if (!unregister)
235		return;
236
237	xdst = (struct xfrm_dst *)dst;
238	if (xdst->u.rt6.rt6i_idev->dev == dev) {
239		struct inet6_dev *loopback_idev =
240			in6_dev_get(dev_net(dev)->loopback_dev);
241		BUG_ON(!loopback_idev);
242
243		do {
244			in6_dev_put(xdst->u.rt6.rt6i_idev);
245			xdst->u.rt6.rt6i_idev = loopback_idev;
246			in6_dev_hold(loopback_idev);
247			xdst = (struct xfrm_dst *)xdst->u.dst.child;
248		} while (xdst->u.dst.xfrm);
249
250		__in6_dev_put(loopback_idev);
251	}
252
253	xfrm_dst_ifdown(dst, dev);
254}
255
256static struct dst_ops xfrm6_dst_ops = {
257	.family =		AF_INET6,
258	.protocol =		cpu_to_be16(ETH_P_IPV6),
259	.gc =			xfrm6_garbage_collect,
260	.update_pmtu =		xfrm6_update_pmtu,
261	.cow_metrics =		dst_cow_metrics_generic,
262	.destroy =		xfrm6_dst_destroy,
263	.ifdown =		xfrm6_dst_ifdown,
264	.local_out =		__ip6_local_out,
265	.gc_thresh =		1024,
266};
267
268static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
269	.family =		AF_INET6,
270	.dst_ops =		&xfrm6_dst_ops,
271	.dst_lookup =		xfrm6_dst_lookup,
272	.get_saddr = 		xfrm6_get_saddr,
273	.decode_session =	_decode_session6,
274	.get_tos =		xfrm6_get_tos,
275	.init_path =		xfrm6_init_path,
276	.fill_dst =		xfrm6_fill_dst,
277};
278
279static int __init xfrm6_policy_init(void)
280{
281	return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
282}
283
284static void xfrm6_policy_fini(void)
285{
286	xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
287}
288
289#ifdef CONFIG_SYSCTL
290static struct ctl_table xfrm6_policy_table[] = {
291	{
292		.procname       = "xfrm6_gc_thresh",
293		.data	   	= &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
294		.maxlen	 	= sizeof(int),
295		.mode	   	= 0644,
296		.proc_handler   = proc_dointvec,
297	},
298	{ }
299};
300
301static struct ctl_table_header *sysctl_hdr;
302#endif
303
304int __init xfrm6_init(void)
305{
306	int ret;
307	unsigned int gc_thresh;
308
309	/*
310	 * We need a good default value for the xfrm6 gc threshold.
311	 * In ipv4 we set it to the route hash table size * 8, which
312	 * is half the size of the maximaum route cache for ipv4.  It
313	 * would be good to do the same thing for v6, except the table is
314	 * constructed differently here.  Here each table for a net namespace
315	 * can have FIB_TABLE_HASHSZ entries, so lets go with the same
316	 * computation that we used for ipv4 here.  Also, lets keep the initial
317	 * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
318	 * to that as a minimum as well
319	 */
320	gc_thresh = FIB6_TABLE_HASHSZ * 8;
321	xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
322	dst_entries_init(&xfrm6_dst_ops);
323
324	ret = xfrm6_policy_init();
325	if (ret) {
326		dst_entries_destroy(&xfrm6_dst_ops);
327		goto out;
328	}
329	ret = xfrm6_state_init();
330	if (ret)
331		goto out_policy;
332
333#ifdef CONFIG_SYSCTL
334	sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
335						xfrm6_policy_table);
336#endif
337out:
338	return ret;
339out_policy:
340	xfrm6_policy_fini();
341	goto out;
342}
343
344void xfrm6_fini(void)
345{
346#ifdef CONFIG_SYSCTL
347	if (sysctl_hdr)
348		unregister_net_sysctl_table(sysctl_hdr);
349#endif
350	//xfrm6_input_fini();
351	xfrm6_policy_fini();
352	xfrm6_state_fini();
353	dst_entries_destroy(&xfrm6_dst_ops);
354}
355