/net/ipv6/xfrm6_policy.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * xfrm6_policy.c: based on xfrm4_policy.c
  4 *
  5 * Authors:
  6 *	Mitsuru KANDA @USAGI
  7 *	Kazunori MIYAZAWA @USAGI
  8 *	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
  9 *		IPv6 support
 10 *	YOSHIFUJI Hideaki
 11 *		Split up af-specific portion
 12 *
 13 */
 14
 15#include <linux/err.h>
 16#include <linux/kernel.h>
 17#include <linux/netdevice.h>
 18#include <net/addrconf.h>
 19#include <net/dst.h>
 20#include <net/xfrm.h>
 21#include <net/ip.h>
 22#include <net/ipv6.h>
 23#include <net/ip6_route.h>
 24#include <net/l3mdev.h>
 25
 26static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif,
 27					  const xfrm_address_t *saddr,
 28					  const xfrm_address_t *daddr,
 29					  u32 mark)
 30{
 31	struct flowi6 fl6;
 32	struct dst_entry *dst;
 33	int err;
 34
 35	memset(&fl6, 0, sizeof(fl6));
 36	fl6.flowi6_oif = l3mdev_master_ifindex_by_index(net, oif);
 37	fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;
 38	fl6.flowi6_mark = mark;
 39	memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
 40	if (saddr)
 41		memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
 42
 43	dst = ip6_route_output(net, NULL, &fl6);
 44
 45	err = dst->error;
 46	if (dst->error) {
 47		dst_release(dst);
 48		dst = ERR_PTR(err);
 49	}
 50
 51	return dst;
 52}
 53
 54static int xfrm6_get_saddr(struct net *net, int oif,
 55			   xfrm_address_t *saddr, xfrm_address_t *daddr,
 56			   u32 mark)
 57{
 58	struct dst_entry *dst;
 59	struct net_device *dev;
 60
 61	dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr, mark);
 62	if (IS_ERR(dst))
 63		return -EHOSTUNREACH;
 64
 65	dev = ip6_dst_idev(dst)->dev;
 66	ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6);
 67	dst_release(dst);
 68	return 0;
 69}
 70
 71static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 72			  const struct flowi *fl)
 73{
 74	struct rt6_info *rt = (struct rt6_info *)xdst->route;
 75
 76	xdst->u.dst.dev = dev;
 77	dev_hold(dev);
 78
 79	xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
 80	if (!xdst->u.rt6.rt6i_idev) {
 81		dev_put(dev);
 82		return -ENODEV;
 83	}
 84
 85	/* Sheit... I remember I did this right. Apparently,
 86	 * it was magically lost, so this code needs audit */
 87	xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 88						   RTF_LOCAL);
 89	xdst->route_cookie = rt6_get_cookie(rt);
 90	xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 91	xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 92	xdst->u.rt6.rt6i_src = rt->rt6i_src;
 93	INIT_LIST_HEAD(&xdst->u.rt6.rt6i_uncached);
 94	rt6_uncached_list_add(&xdst->u.rt6);
 95	atomic_inc(&dev_net(dev)->ipv6.rt6_stats->fib_rt_uncache);
 96
 97	return 0;
 98}
 99
100static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
101			      struct sk_buff *skb, u32 mtu,
102			      bool confirm_neigh)
103{
104	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
105	struct dst_entry *path = xdst->route;
106
107	path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
108}
109
110static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
111			   struct sk_buff *skb)
112{
113	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
114	struct dst_entry *path = xdst->route;
115
116	path->ops->redirect(path, sk, skb);
117}
118
119static void xfrm6_dst_destroy(struct dst_entry *dst)
120{
121	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
122
123	if (likely(xdst->u.rt6.rt6i_idev))
124		in6_dev_put(xdst->u.rt6.rt6i_idev);
125	dst_destroy_metrics_generic(dst);
126	if (xdst->u.rt6.rt6i_uncached_list)
127		rt6_uncached_list_del(&xdst->u.rt6);
128	xfrm_dst_destroy(xdst);
129}
130
131static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
132			     int unregister)
133{
134	struct xfrm_dst *xdst;
135
136	if (!unregister)
137		return;
138
139	xdst = (struct xfrm_dst *)dst;
140	if (xdst->u.rt6.rt6i_idev->dev == dev) {
141		struct inet6_dev *loopback_idev =
142			in6_dev_get(dev_net(dev)->loopback_dev);
143
144		do {
145			in6_dev_put(xdst->u.rt6.rt6i_idev);
146			xdst->u.rt6.rt6i_idev = loopback_idev;
147			in6_dev_hold(loopback_idev);
148			xdst = (struct xfrm_dst *)xfrm_dst_child(&xdst->u.dst);
149		} while (xdst->u.dst.xfrm);
150
151		__in6_dev_put(loopback_idev);
152	}
153
154	xfrm_dst_ifdown(dst, dev);
155}
156
157static struct dst_ops xfrm6_dst_ops_template = {
158	.family =		AF_INET6,
159	.update_pmtu =		xfrm6_update_pmtu,
160	.redirect =		xfrm6_redirect,
161	.cow_metrics =		dst_cow_metrics_generic,
162	.destroy =		xfrm6_dst_destroy,
163	.ifdown =		xfrm6_dst_ifdown,
164	.local_out =		__ip6_local_out,
165	.gc_thresh =		32768,
166};
167
168static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
169	.dst_ops =		&xfrm6_dst_ops_template,
170	.dst_lookup =		xfrm6_dst_lookup,
171	.get_saddr =		xfrm6_get_saddr,
172	.fill_dst =		xfrm6_fill_dst,
173	.blackhole_route =	ip6_blackhole_route,
174};
175
176static int __init xfrm6_policy_init(void)
177{
178	return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6);
179}
180
181static void xfrm6_policy_fini(void)
182{
183	xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
184}
185
186#ifdef CONFIG_SYSCTL
187static struct ctl_table xfrm6_policy_table[] = {
188	{
189		.procname       = "xfrm6_gc_thresh",
190		.data		= &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
191		.maxlen		= sizeof(int),
192		.mode		= 0644,
193		.proc_handler   = proc_dointvec,
194	},
195	{ }
196};
197
198static int __net_init xfrm6_net_sysctl_init(struct net *net)
199{
200	struct ctl_table *table;
201	struct ctl_table_header *hdr;
202
203	table = xfrm6_policy_table;
204	if (!net_eq(net, &init_net)) {
205		table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
206		if (!table)
207			goto err_alloc;
208
209		table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
210	}
211
212	hdr = register_net_sysctl(net, "net/ipv6", table);
213	if (!hdr)
214		goto err_reg;
215
216	net->ipv6.sysctl.xfrm6_hdr = hdr;
217	return 0;
218
219err_reg:
220	if (!net_eq(net, &init_net))
221		kfree(table);
222err_alloc:
223	return -ENOMEM;
224}
225
226static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
227{
228	struct ctl_table *table;
229
230	if (!net->ipv6.sysctl.xfrm6_hdr)
231		return;
232
233	table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
234	unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
235	if (!net_eq(net, &init_net))
236		kfree(table);
237}
238#else /* CONFIG_SYSCTL */
239static inline int xfrm6_net_sysctl_init(struct net *net)
240{
241	return 0;
242}
243
244static inline void xfrm6_net_sysctl_exit(struct net *net)
245{
246}
247#endif
248
249static int __net_init xfrm6_net_init(struct net *net)
250{
251	int ret;
252
253	memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
254	       sizeof(xfrm6_dst_ops_template));
255	ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
256	if (ret)
257		return ret;
258
259	ret = xfrm6_net_sysctl_init(net);
260	if (ret)
261		dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
262
263	return ret;
264}
265
266static void __net_exit xfrm6_net_exit(struct net *net)
267{
268	xfrm6_net_sysctl_exit(net);
269	dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
270}
271
272static struct pernet_operations xfrm6_net_ops = {
273	.init	= xfrm6_net_init,
274	.exit	= xfrm6_net_exit,
275};
276
277int __init xfrm6_init(void)
278{
279	int ret;
280
281	ret = xfrm6_policy_init();
282	if (ret)
283		goto out;
284	ret = xfrm6_state_init();
285	if (ret)
286		goto out_policy;
287
288	ret = xfrm6_protocol_init();
289	if (ret)
290		goto out_state;
291
292	register_pernet_subsys(&xfrm6_net_ops);
293out:
294	return ret;
295out_state:
296	xfrm6_state_fini();
297out_policy:
298	xfrm6_policy_fini();
299	goto out;
300}
301
302void xfrm6_fini(void)
303{
304	unregister_pernet_subsys(&xfrm6_net_ops);
305	xfrm6_protocol_fini();
306	xfrm6_policy_fini();
307	xfrm6_state_fini();
308}