xfrm6_policy.c revision c38132865959c47d36b5db1c9289c7391895be6b 
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 IS_ENABLED(CONFIG_IPV6_MIP6)
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					  const xfrm_address_t *saddr,
31					  const xfrm_address_t *daddr)
32{
33	struct flowi6 fl6;
34	struct dst_entry *dst;
35	int err;
36
37	memset(&fl6, 0, sizeof(fl6));
38	memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
39	if (saddr)
40		memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
41
42	dst = ip6_route_output(net, NULL, &fl6);
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 int xfrm6_get_tos(const struct flowi *fl)
72{
73	return 0;
74}
75
76static void xfrm6_init_dst(struct net *net, struct xfrm_dst *xdst)
77{
78	struct rt6_info *rt = (struct rt6_info *)xdst;
79
80	rt6_init_peer(rt, net->ipv6.peers);
81}
82
83static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
84			   int nfheader_len)
85{
86	if (dst->ops->family == AF_INET6) {
87		struct rt6_info *rt = (struct rt6_info*)dst;
88		if (rt->rt6i_node)
89			path->path_cookie = rt->rt6i_node->fn_sernum;
90	}
91
92	path->u.rt6.rt6i_nfheader_len = nfheader_len;
93
94	return 0;
95}
96
97static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
98			  const struct flowi *fl)
99{
100	struct rt6_info *rt = (struct rt6_info*)xdst->route;
101
102	xdst->u.dst.dev = dev;
103	dev_hold(dev);
104
105	xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
106	if (!xdst->u.rt6.rt6i_idev)
107		return -ENODEV;
108
109	rt6_transfer_peer(&xdst->u.rt6, rt);
110
111	/* Sheit... I remember I did this right. Apparently,
112	 * it was magically lost, so this code needs audit */
113	xdst->u.rt6.n = neigh_clone(rt->n);
114	xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
115						   RTF_LOCAL);
116	xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
117	xdst->u.rt6.rt6i_node = rt->rt6i_node;
118	if (rt->rt6i_node)
119		xdst->route_cookie = rt->rt6i_node->fn_sernum;
120	xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
121	xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
122	xdst->u.rt6.rt6i_src = rt->rt6i_src;
123
124	return 0;
125}
126
127static inline void
128_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
129{
130	struct flowi6 *fl6 = &fl->u.ip6;
131	int onlyproto = 0;
132	u16 offset = skb_network_header_len(skb);
133	const struct ipv6hdr *hdr = ipv6_hdr(skb);
134	struct ipv6_opt_hdr *exthdr;
135	const unsigned char *nh = skb_network_header(skb);
136	u8 nexthdr = nh[IP6CB(skb)->nhoff];
137
138	memset(fl6, 0, sizeof(struct flowi6));
139	fl6->flowi6_mark = skb->mark;
140
141	fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
142	fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
143
144	while (nh + offset + 1 < skb->data ||
145	       pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
146		nh = skb_network_header(skb);
147		exthdr = (struct ipv6_opt_hdr *)(nh + offset);
148
149		switch (nexthdr) {
150		case NEXTHDR_FRAGMENT:
151			onlyproto = 1;
152		case NEXTHDR_ROUTING:
153		case NEXTHDR_HOP:
154		case NEXTHDR_DEST:
155			offset += ipv6_optlen(exthdr);
156			nexthdr = exthdr->nexthdr;
157			exthdr = (struct ipv6_opt_hdr *)(nh + offset);
158			break;
159
160		case IPPROTO_UDP:
161		case IPPROTO_UDPLITE:
162		case IPPROTO_TCP:
163		case IPPROTO_SCTP:
164		case IPPROTO_DCCP:
165			if (!onlyproto && (nh + offset + 4 < skb->data ||
166			     pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
167				__be16 *ports = (__be16 *)exthdr;
168
169				fl6->fl6_sport = ports[!!reverse];
170				fl6->fl6_dport = ports[!reverse];
171			}
172			fl6->flowi6_proto = nexthdr;
173			return;
174
175		case IPPROTO_ICMPV6:
176			if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
177				u8 *icmp = (u8 *)exthdr;
178
179				fl6->fl6_icmp_type = icmp[0];
180				fl6->fl6_icmp_code = icmp[1];
181			}
182			fl6->flowi6_proto = nexthdr;
183			return;
184
185#if IS_ENABLED(CONFIG_IPV6_MIP6)
186		case IPPROTO_MH:
187			if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
188				struct ip6_mh *mh;
189				mh = (struct ip6_mh *)exthdr;
190
191				fl6->fl6_mh_type = mh->ip6mh_type;
192			}
193			fl6->flowi6_proto = nexthdr;
194			return;
195#endif
196
197		/* XXX Why are there these headers? */
198		case IPPROTO_AH:
199		case IPPROTO_ESP:
200		case IPPROTO_COMP:
201		default:
202			fl6->fl6_ipsec_spi = 0;
203			fl6->flowi6_proto = nexthdr;
204			return;
205		}
206	}
207}
208
209static inline int xfrm6_garbage_collect(struct dst_ops *ops)
210{
211	struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
212
213	xfrm6_policy_afinfo.garbage_collect(net);
214	return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
215}
216
217static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
218			      struct sk_buff *skb, u32 mtu)
219{
220	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
221	struct dst_entry *path = xdst->route;
222
223	path->ops->update_pmtu(path, sk, skb, mtu);
224}
225
226static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
227			   struct sk_buff *skb)
228{
229	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
230	struct dst_entry *path = xdst->route;
231
232	path->ops->redirect(path, sk, skb);
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	dst_destroy_metrics_generic(dst);
242	if (rt6_has_peer(&xdst->u.rt6)) {
243		struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
244		inet_putpeer(peer);
245	}
246	xfrm_dst_destroy(xdst);
247}
248
249static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
250			     int unregister)
251{
252	struct xfrm_dst *xdst;
253
254	if (!unregister)
255		return;
256
257	xdst = (struct xfrm_dst *)dst;
258	if (xdst->u.rt6.rt6i_idev->dev == dev) {
259		struct inet6_dev *loopback_idev =
260			in6_dev_get(dev_net(dev)->loopback_dev);
261		BUG_ON(!loopback_idev);
262
263		do {
264			in6_dev_put(xdst->u.rt6.rt6i_idev);
265			xdst->u.rt6.rt6i_idev = loopback_idev;
266			in6_dev_hold(loopback_idev);
267			xdst = (struct xfrm_dst *)xdst->u.dst.child;
268		} while (xdst->u.dst.xfrm);
269
270		__in6_dev_put(loopback_idev);
271	}
272
273	xfrm_dst_ifdown(dst, dev);
274}
275
276static struct dst_ops xfrm6_dst_ops = {
277	.family =		AF_INET6,
278	.protocol =		cpu_to_be16(ETH_P_IPV6),
279	.gc =			xfrm6_garbage_collect,
280	.update_pmtu =		xfrm6_update_pmtu,
281	.redirect =		xfrm6_redirect,
282	.cow_metrics =		dst_cow_metrics_generic,
283	.destroy =		xfrm6_dst_destroy,
284	.ifdown =		xfrm6_dst_ifdown,
285	.local_out =		__ip6_local_out,
286	.gc_thresh =		1024,
287};
288
289static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
290	.family =		AF_INET6,
291	.dst_ops =		&xfrm6_dst_ops,
292	.dst_lookup =		xfrm6_dst_lookup,
293	.get_saddr = 		xfrm6_get_saddr,
294	.decode_session =	_decode_session6,
295	.get_tos =		xfrm6_get_tos,
296	.init_dst =		xfrm6_init_dst,
297	.init_path =		xfrm6_init_path,
298	.fill_dst =		xfrm6_fill_dst,
299	.blackhole_route =	ip6_blackhole_route,
300};
301
302static int __init xfrm6_policy_init(void)
303{
304	return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
305}
306
307static void xfrm6_policy_fini(void)
308{
309	xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
310}
311
312#ifdef CONFIG_SYSCTL
313static struct ctl_table xfrm6_policy_table[] = {
314	{
315		.procname       = "xfrm6_gc_thresh",
316		.data	   	= &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
317		.maxlen	 	= sizeof(int),
318		.mode	   	= 0644,
319		.proc_handler   = proc_dointvec,
320	},
321	{ }
322};
323
324static struct ctl_table_header *sysctl_hdr;
325#endif
326
327int __init xfrm6_init(void)
328{
329	int ret;
330
331	dst_entries_init(&xfrm6_dst_ops);
332
333	ret = xfrm6_policy_init();
334	if (ret) {
335		dst_entries_destroy(&xfrm6_dst_ops);
336		goto out;
337	}
338	ret = xfrm6_state_init();
339	if (ret)
340		goto out_policy;
341
342#ifdef CONFIG_SYSCTL
343	sysctl_hdr = register_net_sysctl(&init_net, "net/ipv6",
344					 xfrm6_policy_table);
345#endif
346out:
347	return ret;
348out_policy:
349	xfrm6_policy_fini();
350	goto out;
351}
352
353void xfrm6_fini(void)
354{
355#ifdef CONFIG_SYSCTL
356	if (sysctl_hdr)
357		unregister_net_sysctl_table(sysctl_hdr);
358#endif
359	//xfrm6_input_fini();
360	xfrm6_policy_fini();
361	xfrm6_state_fini();
362	dst_entries_destroy(&xfrm6_dst_ops);
363}
364