/net/ipv4/xfrm4_policy.c

  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_oif = l3mdev_master_ifindex_by_index(net, oif);
 32	fl4->flowi4_mark = mark;
 33	if (saddr)
 34		fl4->saddr = saddr->a4;
 35
 36	fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF;
 37
 38	rt = __ip_route_output_key(net, fl4);
 39	if (!IS_ERR(rt))
 40		return &rt->dst;
 41
 42	return ERR_CAST(rt);
 43}
 44
 45static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
 46					  const xfrm_address_t *saddr,
 47					  const xfrm_address_t *daddr,
 48					  u32 mark)
 49{
 50	struct flowi4 fl4;
 51
 52	return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark);
 53}
 54
 55static int xfrm4_get_saddr(struct net *net, int oif,
 56			   xfrm_address_t *saddr, xfrm_address_t *daddr,
 57			   u32 mark)
 58{
 59	struct dst_entry *dst;
 60	struct flowi4 fl4;
 61
 62	dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark);
 63	if (IS_ERR(dst))
 64		return -EHOSTUNREACH;
 65
 66	saddr->a4 = fl4.saddr;
 67	dst_release(dst);
 68	return 0;
 69}
 70
 71static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 72			  const struct flowi *fl)
 73{
 74	struct rtable *rt = (struct rtable *)xdst->route;
 75	const struct flowi4 *fl4 = &fl->u.ip4;
 76
 77	xdst->u.rt.rt_iif = fl4->flowi4_iif;
 78
 79	xdst->u.dst.dev = dev;
 80	dev_hold(dev);
 81
 82	/* Sheit... I remember I did this right. Apparently,
 83	 * it was magically lost, so this code needs audit */
 84	xdst->u.rt.rt_is_input = rt->rt_is_input;
 85	xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
 86					      RTCF_LOCAL);
 87	xdst->u.rt.rt_type = rt->rt_type;
 88	xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
 89	xdst->u.rt.rt_gw_family = rt->rt_gw_family;
 90	if (rt->rt_gw_family == AF_INET)
 91		xdst->u.rt.rt_gw4 = rt->rt_gw4;
 92	else if (rt->rt_gw_family == AF_INET6)
 93		xdst->u.rt.rt_gw6 = rt->rt_gw6;
 94	xdst->u.rt.rt_pmtu = rt->rt_pmtu;
 95	xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
 96	INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
 97	rt_add_uncached_list(&xdst->u.rt);
 98
 99	return 0;
100}
101
102static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
103			      struct sk_buff *skb, u32 mtu,
104			      bool confirm_neigh)
105{
106	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
107	struct dst_entry *path = xdst->route;
108
109	path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
110}
111
112static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
113			   struct sk_buff *skb)
114{
115	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
116	struct dst_entry *path = xdst->route;
117
118	path->ops->redirect(path, sk, skb);
119}
120
121static void xfrm4_dst_destroy(struct dst_entry *dst)
122{
123	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
124
125	dst_destroy_metrics_generic(dst);
126	if (xdst->u.rt.rt_uncached_list)
127		rt_del_uncached_list(&xdst->u.rt);
128	xfrm_dst_destroy(xdst);
129}
130
131static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
132			     int unregister)
133{
134	if (!unregister)
135		return;
136
137	xfrm_dst_ifdown(dst, dev);
138}
139
140static struct dst_ops xfrm4_dst_ops_template = {
141	.family =		AF_INET,
142	.update_pmtu =		xfrm4_update_pmtu,
143	.redirect =		xfrm4_redirect,
144	.cow_metrics =		dst_cow_metrics_generic,
145	.destroy =		xfrm4_dst_destroy,
146	.ifdown =		xfrm4_dst_ifdown,
147	.local_out =		__ip_local_out,
148	.gc_thresh =		32768,
149};
150
151static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
152	.dst_ops =		&xfrm4_dst_ops_template,
153	.dst_lookup =		xfrm4_dst_lookup,
154	.get_saddr =		xfrm4_get_saddr,
155	.fill_dst =		xfrm4_fill_dst,
156	.blackhole_route =	ipv4_blackhole_route,
157};
158
159#ifdef CONFIG_SYSCTL
160static struct ctl_table xfrm4_policy_table[] = {
161	{
162		.procname       = "xfrm4_gc_thresh",
163		.data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
164		.maxlen         = sizeof(int),
165		.mode           = 0644,
166		.proc_handler   = proc_dointvec,
167	},
168	{ }
169};
170
171static __net_init int xfrm4_net_sysctl_init(struct net *net)
172{
173	struct ctl_table *table;
174	struct ctl_table_header *hdr;
175
176	table = xfrm4_policy_table;
177	if (!net_eq(net, &init_net)) {
178		table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
179		if (!table)
180			goto err_alloc;
181
182		table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
183	}
184
185	hdr = register_net_sysctl(net, "net/ipv4", table);
186	if (!hdr)
187		goto err_reg;
188
189	net->ipv4.xfrm4_hdr = hdr;
190	return 0;
191
192err_reg:
193	if (!net_eq(net, &init_net))
194		kfree(table);
195err_alloc:
196	return -ENOMEM;
197}
198
199static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
200{
201	struct ctl_table *table;
202
203	if (!net->ipv4.xfrm4_hdr)
204		return;
205
206	table = net->ipv4.xfrm4_hdr->ctl_table_arg;
207	unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
208	if (!net_eq(net, &init_net))
209		kfree(table);
210}
211#else /* CONFIG_SYSCTL */
212static inline int xfrm4_net_sysctl_init(struct net *net)
213{
214	return 0;
215}
216
217static inline void xfrm4_net_sysctl_exit(struct net *net)
218{
219}
220#endif
221
222static int __net_init xfrm4_net_init(struct net *net)
223{
224	int ret;
225
226	memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
227	       sizeof(xfrm4_dst_ops_template));
228	ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
229	if (ret)
230		return ret;
231
232	ret = xfrm4_net_sysctl_init(net);
233	if (ret)
234		dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
235
236	return ret;
237}
238
239static void __net_exit xfrm4_net_exit(struct net *net)
240{
241	xfrm4_net_sysctl_exit(net);
242	dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
243}
244
245static struct pernet_operations __net_initdata xfrm4_net_ops = {
246	.init	= xfrm4_net_init,
247	.exit	= xfrm4_net_exit,
248};
249
250static void __init xfrm4_policy_init(void)
251{
252	xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
253}
254
255void __init xfrm4_init(void)
256{
257	xfrm4_state_init();
258	xfrm4_policy_init();
259	xfrm4_protocol_init();
260	register_pernet_subsys(&xfrm4_net_ops);
261}