1// SPDX-License-Identifier: GPL-2.0
2/*
3 * xfrm4_policy.c
4 *
5 * Changes:
6 *	Kazunori MIYAZAWA @USAGI
7 * 	YOSHIFUJI Hideaki @USAGI
8 *		Split up af-specific portion
9 *
10 */
11
12#include <linux/err.h>
13#include <linux/kernel.h>
14#include <linux/inetdevice.h>
15#include <net/dst.h>
16#include <net/xfrm.h>
17#include <net/ip.h>
18#include <net/l3mdev.h>
19
20static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
21					    int tos, int oif,
22					    const xfrm_address_t *saddr,
23					    const xfrm_address_t *daddr,
24					    u32 mark)
25{
26	struct rtable *rt;
27
28	memset(fl4, 0, sizeof(*fl4));
29	fl4->daddr = daddr->a4;
30	fl4->flowi4_tos = tos;
31	fl4->flowi4_l3mdev = l3mdev_master_ifindex_by_index(net, oif);
32	fl4->flowi4_mark = mark;
33	if (saddr)
34		fl4->saddr = saddr->a4;
35
36	rt = __ip_route_output_key(net, fl4);
37	if (!IS_ERR(rt))
38		return &rt->dst;
39
40	return ERR_CAST(rt);
41}
42
43static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
44					  const xfrm_address_t *saddr,
45					  const xfrm_address_t *daddr,
46					  u32 mark)
47{
48	struct flowi4 fl4;
49
50	return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark);
51}
52
53static int xfrm4_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 flowi4 fl4;
59
60	dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark);
61	if (IS_ERR(dst))
62		return -EHOSTUNREACH;
63
64	saddr->a4 = fl4.saddr;
65	dst_release(dst);
66	return 0;
67}
68
69static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
70			  const struct flowi *fl)
71{
72	struct rtable *rt = (struct rtable *)xdst->route;
73	const struct flowi4 *fl4 = &fl->u.ip4;
74
75	xdst->u.rt.rt_iif = fl4->flowi4_iif;
76
77	xdst->u.dst.dev = dev;
78	netdev_hold(dev, &xdst->u.dst.dev_tracker, GFP_ATOMIC);
79
80	/* Sheit... I remember I did this right. Apparently,
81	 * it was magically lost, so this code needs audit */
82	xdst->u.rt.rt_is_input = rt->rt_is_input;
83	xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
84					      RTCF_LOCAL);
85	xdst->u.rt.rt_type = rt->rt_type;
86	xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
87	xdst->u.rt.rt_gw_family = rt->rt_gw_family;
88	if (rt->rt_gw_family == AF_INET)
89		xdst->u.rt.rt_gw4 = rt->rt_gw4;
90	else if (rt->rt_gw_family == AF_INET6)
91		xdst->u.rt.rt_gw6 = rt->rt_gw6;
92	xdst->u.rt.rt_pmtu = rt->rt_pmtu;
93	xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
94	rt_add_uncached_list(&xdst->u.rt);
95
96	return 0;
97}
98
99static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
100			      struct sk_buff *skb, u32 mtu,
101			      bool confirm_neigh)
102{
103	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
104	struct dst_entry *path = xdst->route;
105
106	path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
107}
108
109static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
110			   struct sk_buff *skb)
111{
112	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
113	struct dst_entry *path = xdst->route;
114
115	path->ops->redirect(path, sk, skb);
116}
117
118static void xfrm4_dst_destroy(struct dst_entry *dst)
119{
120	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
121
122	dst_destroy_metrics_generic(dst);
123	rt_del_uncached_list(&xdst->u.rt);
124	xfrm_dst_destroy(xdst);
125}
126
127static struct dst_ops xfrm4_dst_ops_template = {
128	.family =		AF_INET,
129	.update_pmtu =		xfrm4_update_pmtu,
130	.redirect =		xfrm4_redirect,
131	.cow_metrics =		dst_cow_metrics_generic,
132	.destroy =		xfrm4_dst_destroy,
133	.ifdown =		xfrm_dst_ifdown,
134	.local_out =		__ip_local_out,
135	.gc_thresh =		32768,
136};
137
138static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
139	.dst_ops =		&xfrm4_dst_ops_template,
140	.dst_lookup =		xfrm4_dst_lookup,
141	.get_saddr =		xfrm4_get_saddr,
142	.fill_dst =		xfrm4_fill_dst,
143	.blackhole_route =	ipv4_blackhole_route,
144};
145
146#ifdef CONFIG_SYSCTL
147static struct ctl_table xfrm4_policy_table[] = {
148	{
149		.procname       = "xfrm4_gc_thresh",
150		.data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
151		.maxlen         = sizeof(int),
152		.mode           = 0644,
153		.proc_handler   = proc_dointvec,
154	},
155	{ }
156};
157
158static __net_init int xfrm4_net_sysctl_init(struct net *net)
159{
160	struct ctl_table *table;
161	struct ctl_table_header *hdr;
162
163	table = xfrm4_policy_table;
164	if (!net_eq(net, &init_net)) {
165		table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
166		if (!table)
167			goto err_alloc;
168
169		table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
170	}
171
172	hdr = register_net_sysctl_sz(net, "net/ipv4", table,
173				     ARRAY_SIZE(xfrm4_policy_table));
174	if (!hdr)
175		goto err_reg;
176
177	net->ipv4.xfrm4_hdr = hdr;
178	return 0;
179
180err_reg:
181	if (!net_eq(net, &init_net))
182		kfree(table);
183err_alloc:
184	return -ENOMEM;
185}
186
187static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
188{
189	struct ctl_table *table;
190
191	if (!net->ipv4.xfrm4_hdr)
192		return;
193
194	table = net->ipv4.xfrm4_hdr->ctl_table_arg;
195	unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
196	if (!net_eq(net, &init_net))
197		kfree(table);
198}
199#else /* CONFIG_SYSCTL */
200static inline int xfrm4_net_sysctl_init(struct net *net)
201{
202	return 0;
203}
204
205static inline void xfrm4_net_sysctl_exit(struct net *net)
206{
207}
208#endif
209
210static int __net_init xfrm4_net_init(struct net *net)
211{
212	int ret;
213
214	memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
215	       sizeof(xfrm4_dst_ops_template));
216	ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
217	if (ret)
218		return ret;
219
220	ret = xfrm4_net_sysctl_init(net);
221	if (ret)
222		dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
223
224	return ret;
225}
226
227static void __net_exit xfrm4_net_exit(struct net *net)
228{
229	xfrm4_net_sysctl_exit(net);
230	dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
231}
232
233static struct pernet_operations __net_initdata xfrm4_net_ops = {
234	.init	= xfrm4_net_init,
235	.exit	= xfrm4_net_exit,
236};
237
238static void __init xfrm4_policy_init(void)
239{
240	xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
241}
242
243void __init xfrm4_init(void)
244{
245	xfrm4_state_init();
246	xfrm4_policy_init();
247	xfrm4_protocol_init();
248	register_pernet_subsys(&xfrm4_net_ops);
249}
250