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_l3mdev = l3mdev_master_ifindex_by_index(net, oif);
37	fl6.flowi6_mark = mark;
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, int oif,
54			   xfrm_address_t *saddr, xfrm_address_t *daddr,
55			   u32 mark)
56{
57	struct dst_entry *dst;
58	struct net_device *dev;
59
60	dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr, mark);
61	if (IS_ERR(dst))
62		return -EHOSTUNREACH;
63
64	dev = ip6_dst_idev(dst)->dev;
65	ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6);
66	dst_release(dst);
67	return 0;
68}
69
70static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
71			  const struct flowi *fl)
72{
73	struct rt6_info *rt = (struct rt6_info *)xdst->route;
74
75	xdst->u.dst.dev = dev;
76	netdev_hold(dev, &xdst->u.dst.dev_tracker, GFP_ATOMIC);
77
78	xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
79	if (!xdst->u.rt6.rt6i_idev) {
80		netdev_put(dev, &xdst->u.dst.dev_tracker);
81		return -ENODEV;
82	}
83
84	/* Sheit... I remember I did this right. Apparently,
85	 * it was magically lost, so this code needs audit */
86	xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
87						   RTF_LOCAL);
88	xdst->route_cookie = rt6_get_cookie(rt);
89	xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
90	xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
91	xdst->u.rt6.rt6i_src = rt->rt6i_src;
92	rt6_uncached_list_add(&xdst->u.rt6);
93
94	return 0;
95}
96
97static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
98			      struct sk_buff *skb, u32 mtu,
99			      bool confirm_neigh)
100{
101	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
102	struct dst_entry *path = xdst->route;
103
104	path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
105}
106
107static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
108			   struct sk_buff *skb)
109{
110	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
111	struct dst_entry *path = xdst->route;
112
113	path->ops->redirect(path, sk, skb);
114}
115
116static void xfrm6_dst_destroy(struct dst_entry *dst)
117{
118	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
119
120	dst_destroy_metrics_generic(dst);
121	rt6_uncached_list_del(&xdst->u.rt6);
122	if (likely(xdst->u.rt6.rt6i_idev))
123		in6_dev_put(xdst->u.rt6.rt6i_idev);
124	xfrm_dst_destroy(xdst);
125}
126
127static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
128{
129	struct xfrm_dst *xdst;
130
131	xdst = (struct xfrm_dst *)dst;
132	if (xdst->u.rt6.rt6i_idev->dev == dev) {
133		struct inet6_dev *loopback_idev =
134			in6_dev_get(dev_net(dev)->loopback_dev);
135
136		do {
137			in6_dev_put(xdst->u.rt6.rt6i_idev);
138			xdst->u.rt6.rt6i_idev = loopback_idev;
139			in6_dev_hold(loopback_idev);
140			xdst = (struct xfrm_dst *)xfrm_dst_child(&xdst->u.dst);
141		} while (xdst->u.dst.xfrm);
142
143		__in6_dev_put(loopback_idev);
144	}
145
146	xfrm_dst_ifdown(dst, dev);
147}
148
149static struct dst_ops xfrm6_dst_ops_template = {
150	.family =		AF_INET6,
151	.update_pmtu =		xfrm6_update_pmtu,
152	.redirect =		xfrm6_redirect,
153	.cow_metrics =		dst_cow_metrics_generic,
154	.destroy =		xfrm6_dst_destroy,
155	.ifdown =		xfrm6_dst_ifdown,
156	.local_out =		__ip6_local_out,
157	.gc_thresh =		32768,
158};
159
160static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
161	.dst_ops =		&xfrm6_dst_ops_template,
162	.dst_lookup =		xfrm6_dst_lookup,
163	.get_saddr =		xfrm6_get_saddr,
164	.fill_dst =		xfrm6_fill_dst,
165	.blackhole_route =	ip6_blackhole_route,
166};
167
168static int __init xfrm6_policy_init(void)
169{
170	return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6);
171}
172
173static void xfrm6_policy_fini(void)
174{
175	xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
176}
177
178#ifdef CONFIG_SYSCTL
179static struct ctl_table xfrm6_policy_table[] = {
180	{
181		.procname       = "xfrm6_gc_thresh",
182		.data		= &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
183		.maxlen		= sizeof(int),
184		.mode		= 0644,
185		.proc_handler   = proc_dointvec,
186	},
187	{ }
188};
189
190static int __net_init xfrm6_net_sysctl_init(struct net *net)
191{
192	struct ctl_table *table;
193	struct ctl_table_header *hdr;
194
195	table = xfrm6_policy_table;
196	if (!net_eq(net, &init_net)) {
197		table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
198		if (!table)
199			goto err_alloc;
200
201		table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
202	}
203
204	hdr = register_net_sysctl_sz(net, "net/ipv6", table,
205				     ARRAY_SIZE(xfrm6_policy_table));
206	if (!hdr)
207		goto err_reg;
208
209	net->ipv6.sysctl.xfrm6_hdr = hdr;
210	return 0;
211
212err_reg:
213	if (!net_eq(net, &init_net))
214		kfree(table);
215err_alloc:
216	return -ENOMEM;
217}
218
219static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
220{
221	struct ctl_table *table;
222
223	if (!net->ipv6.sysctl.xfrm6_hdr)
224		return;
225
226	table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
227	unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
228	if (!net_eq(net, &init_net))
229		kfree(table);
230}
231#else /* CONFIG_SYSCTL */
232static inline int xfrm6_net_sysctl_init(struct net *net)
233{
234	return 0;
235}
236
237static inline void xfrm6_net_sysctl_exit(struct net *net)
238{
239}
240#endif
241
242static int __net_init xfrm6_net_init(struct net *net)
243{
244	int ret;
245
246	memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
247	       sizeof(xfrm6_dst_ops_template));
248	ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
249	if (ret)
250		return ret;
251
252	ret = xfrm6_net_sysctl_init(net);
253	if (ret)
254		dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
255
256	return ret;
257}
258
259static void __net_exit xfrm6_net_exit(struct net *net)
260{
261	xfrm6_net_sysctl_exit(net);
262	dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
263}
264
265static struct pernet_operations xfrm6_net_ops = {
266	.init	= xfrm6_net_init,
267	.exit	= xfrm6_net_exit,
268};
269
270int __init xfrm6_init(void)
271{
272	int ret;
273
274	ret = xfrm6_policy_init();
275	if (ret)
276		goto out;
277	ret = xfrm6_state_init();
278	if (ret)
279		goto out_policy;
280
281	ret = xfrm6_protocol_init();
282	if (ret)
283		goto out_state;
284
285	ret = register_pernet_subsys(&xfrm6_net_ops);
286	if (ret)
287		goto out_protocol;
288out:
289	return ret;
290out_protocol:
291	xfrm6_protocol_fini();
292out_state:
293	xfrm6_state_fini();
294out_policy:
295	xfrm6_policy_fini();
296	goto out;
297}
298
299void xfrm6_fini(void)
300{
301	unregister_pernet_subsys(&xfrm6_net_ops);
302	xfrm6_protocol_fini();
303	xfrm6_policy_fini();
304	xfrm6_state_fini();
305}
306