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v4.17
  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 <linux/if_tunnel.h>
 16#include <net/dst.h>
 17#include <net/xfrm.h>
 18#include <net/ip.h>
 19#include <net/l3mdev.h>
 20
 21static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
 22					    int tos, int oif,
 23					    const xfrm_address_t *saddr,
 24					    const xfrm_address_t *daddr,
 25					    u32 mark)
 26{
 27	struct rtable *rt;
 28
 29	memset(fl4, 0, sizeof(*fl4));
 30	fl4->daddr = daddr->a4;
 31	fl4->flowi4_tos = tos;
 32	fl4->flowi4_oif = l3mdev_master_ifindex_by_index(net, oif);
 33	fl4->flowi4_mark = mark;
 34	if (saddr)
 35		fl4->saddr = saddr->a4;
 36
 37	fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF;
 38
 39	rt = __ip_route_output_key(net, fl4);
 40	if (!IS_ERR(rt))
 41		return &rt->dst;
 42
 43	return ERR_CAST(rt);
 44}
 45
 46static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
 47					  const xfrm_address_t *saddr,
 48					  const xfrm_address_t *daddr,
 49					  u32 mark)
 50{
 51	struct flowi4 fl4;
 52
 53	return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark);
 54}
 55
 56static int xfrm4_get_saddr(struct net *net, int oif,
 57			   xfrm_address_t *saddr, xfrm_address_t *daddr,
 58			   u32 mark)
 59{
 60	struct dst_entry *dst;
 61	struct flowi4 fl4;
 62
 63	dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark);
 64	if (IS_ERR(dst))
 65		return -EHOSTUNREACH;
 66
 67	saddr->a4 = fl4.saddr;
 68	dst_release(dst);
 69	return 0;
 70}
 71
 72static int xfrm4_get_tos(const struct flowi *fl)
 73{
 74	return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */
 75}
 76
 77static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst,
 78			   int nfheader_len)
 79{
 80	return 0;
 81}
 82
 83static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 84			  const struct flowi *fl)
 85{
 86	struct rtable *rt = (struct rtable *)xdst->route;
 87	const struct flowi4 *fl4 = &fl->u.ip4;
 88
 89	xdst->u.rt.rt_iif = fl4->flowi4_iif;
 90
 91	xdst->u.dst.dev = dev;
 92	dev_hold(dev);
 93
 94	/* Sheit... I remember I did this right. Apparently,
 95	 * it was magically lost, so this code needs audit */
 96	xdst->u.rt.rt_is_input = rt->rt_is_input;
 97	xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
 98					      RTCF_LOCAL);
 99	xdst->u.rt.rt_type = rt->rt_type;
100	xdst->u.rt.rt_gateway = rt->rt_gateway;
101	xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
102	xdst->u.rt.rt_pmtu = rt->rt_pmtu;
103	xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
104	INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
105	rt_add_uncached_list(&xdst->u.rt);
106
107	return 0;
108}
109
110static void
111_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
112{
113	const struct iphdr *iph = ip_hdr(skb);
114	u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
115	struct flowi4 *fl4 = &fl->u.ip4;
116	int oif = 0;
117
118	if (skb_dst(skb))
119		oif = skb_dst(skb)->dev->ifindex;
120
121	memset(fl4, 0, sizeof(struct flowi4));
122	fl4->flowi4_mark = skb->mark;
123	fl4->flowi4_oif = reverse ? skb->skb_iif : oif;
124
125	if (!ip_is_fragment(iph)) {
126		switch (iph->protocol) {
127		case IPPROTO_UDP:
128		case IPPROTO_UDPLITE:
129		case IPPROTO_TCP:
130		case IPPROTO_SCTP:
131		case IPPROTO_DCCP:
132			if (xprth + 4 < skb->data ||
133			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
134				__be16 *ports;
135
136				xprth = skb_network_header(skb) + iph->ihl * 4;
137				ports = (__be16 *)xprth;
138
139				fl4->fl4_sport = ports[!!reverse];
140				fl4->fl4_dport = ports[!reverse];
141			}
142			break;
143
144		case IPPROTO_ICMP:
145			if (xprth + 2 < skb->data ||
146			    pskb_may_pull(skb, xprth + 2 - skb->data)) {
147				u8 *icmp;
148
149				xprth = skb_network_header(skb) + iph->ihl * 4;
150				icmp = xprth;
151
152				fl4->fl4_icmp_type = icmp[0];
153				fl4->fl4_icmp_code = icmp[1];
154			}
155			break;
156
157		case IPPROTO_ESP:
158			if (xprth + 4 < skb->data ||
159			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
160				__be32 *ehdr;
161
162				xprth = skb_network_header(skb) + iph->ihl * 4;
163				ehdr = (__be32 *)xprth;
164
165				fl4->fl4_ipsec_spi = ehdr[0];
166			}
167			break;
168
169		case IPPROTO_AH:
170			if (xprth + 8 < skb->data ||
171			    pskb_may_pull(skb, xprth + 8 - skb->data)) {
172				__be32 *ah_hdr;
173
174				xprth = skb_network_header(skb) + iph->ihl * 4;
175				ah_hdr = (__be32 *)xprth;
176
177				fl4->fl4_ipsec_spi = ah_hdr[1];
178			}
179			break;
180
181		case IPPROTO_COMP:
182			if (xprth + 4 < skb->data ||
183			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
184				__be16 *ipcomp_hdr;
185
186				xprth = skb_network_header(skb) + iph->ihl * 4;
187				ipcomp_hdr = (__be16 *)xprth;
188
189				fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
190			}
191			break;
192
193		case IPPROTO_GRE:
194			if (xprth + 12 < skb->data ||
195			    pskb_may_pull(skb, xprth + 12 - skb->data)) {
196				__be16 *greflags;
197				__be32 *gre_hdr;
198
199				xprth = skb_network_header(skb) + iph->ihl * 4;
200				greflags = (__be16 *)xprth;
201				gre_hdr = (__be32 *)xprth;
202
203				if (greflags[0] & GRE_KEY) {
204					if (greflags[0] & GRE_CSUM)
205						gre_hdr++;
206					fl4->fl4_gre_key = gre_hdr[1];
207				}
208			}
209			break;
210
211		default:
212			fl4->fl4_ipsec_spi = 0;
213			break;
214		}
215	}
216	fl4->flowi4_proto = iph->protocol;
217	fl4->daddr = reverse ? iph->saddr : iph->daddr;
218	fl4->saddr = reverse ? iph->daddr : iph->saddr;
219	fl4->flowi4_tos = iph->tos;
220}
221
222static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
223			      struct sk_buff *skb, u32 mtu)
224{
225	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
226	struct dst_entry *path = xdst->route;
227
228	path->ops->update_pmtu(path, sk, skb, mtu);
229}
230
231static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
232			   struct sk_buff *skb)
233{
234	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
235	struct dst_entry *path = xdst->route;
236
237	path->ops->redirect(path, sk, skb);
238}
239
240static void xfrm4_dst_destroy(struct dst_entry *dst)
241{
242	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
243
244	dst_destroy_metrics_generic(dst);
245	if (xdst->u.rt.rt_uncached_list)
246		rt_del_uncached_list(&xdst->u.rt);
247	xfrm_dst_destroy(xdst);
248}
249
250static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
251			     int unregister)
252{
253	if (!unregister)
254		return;
255
256	xfrm_dst_ifdown(dst, dev);
257}
258
259static struct dst_ops xfrm4_dst_ops_template = {
260	.family =		AF_INET,
261	.update_pmtu =		xfrm4_update_pmtu,
262	.redirect =		xfrm4_redirect,
263	.cow_metrics =		dst_cow_metrics_generic,
264	.destroy =		xfrm4_dst_destroy,
265	.ifdown =		xfrm4_dst_ifdown,
266	.local_out =		__ip_local_out,
267	.gc_thresh =		32768,
268};
269
270static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
271	.dst_ops =		&xfrm4_dst_ops_template,
272	.dst_lookup =		xfrm4_dst_lookup,
273	.get_saddr =		xfrm4_get_saddr,
274	.decode_session =	_decode_session4,
275	.get_tos =		xfrm4_get_tos,
276	.init_path =		xfrm4_init_path,
277	.fill_dst =		xfrm4_fill_dst,
278	.blackhole_route =	ipv4_blackhole_route,
279};
280
281#ifdef CONFIG_SYSCTL
282static struct ctl_table xfrm4_policy_table[] = {
283	{
284		.procname       = "xfrm4_gc_thresh",
285		.data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
286		.maxlen         = sizeof(int),
287		.mode           = 0644,
288		.proc_handler   = proc_dointvec,
289	},
290	{ }
291};
292
293static __net_init int xfrm4_net_sysctl_init(struct net *net)
294{
295	struct ctl_table *table;
296	struct ctl_table_header *hdr;
297
298	table = xfrm4_policy_table;
299	if (!net_eq(net, &init_net)) {
300		table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
301		if (!table)
302			goto err_alloc;
303
304		table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
305	}
306
307	hdr = register_net_sysctl(net, "net/ipv4", table);
308	if (!hdr)
309		goto err_reg;
310
311	net->ipv4.xfrm4_hdr = hdr;
312	return 0;
313
314err_reg:
315	if (!net_eq(net, &init_net))
316		kfree(table);
317err_alloc:
318	return -ENOMEM;
319}
320
321static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
322{
323	struct ctl_table *table;
324
325	if (!net->ipv4.xfrm4_hdr)
326		return;
327
328	table = net->ipv4.xfrm4_hdr->ctl_table_arg;
329	unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
330	if (!net_eq(net, &init_net))
331		kfree(table);
332}
333#else /* CONFIG_SYSCTL */
334static inline int xfrm4_net_sysctl_init(struct net *net)
335{
336	return 0;
337}
338
339static inline void xfrm4_net_sysctl_exit(struct net *net)
340{
341}
342#endif
343
344static int __net_init xfrm4_net_init(struct net *net)
345{
346	int ret;
347
348	memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
349	       sizeof(xfrm4_dst_ops_template));
350	ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
351	if (ret)
352		return ret;
353
354	ret = xfrm4_net_sysctl_init(net);
355	if (ret)
356		dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
357
358	return ret;
359}
360
361static void __net_exit xfrm4_net_exit(struct net *net)
362{
363	xfrm4_net_sysctl_exit(net);
364	dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
365}
366
367static struct pernet_operations __net_initdata xfrm4_net_ops = {
368	.init	= xfrm4_net_init,
369	.exit	= xfrm4_net_exit,
370};
371
372static void __init xfrm4_policy_init(void)
373{
374	xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
375}
376
377void __init xfrm4_init(void)
378{
379	xfrm4_state_init();
380	xfrm4_policy_init();
381	xfrm4_protocol_init();
382	register_pernet_subsys(&xfrm4_net_ops);
383}
v4.17
  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 <linux/if_tunnel.h>
 16#include <net/dst.h>
 17#include <net/xfrm.h>
 18#include <net/ip.h>
 19#include <net/l3mdev.h>
 20
 21static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
 22					    int tos, int oif,
 23					    const xfrm_address_t *saddr,
 24					    const xfrm_address_t *daddr,
 25					    u32 mark)
 26{
 27	struct rtable *rt;
 28
 29	memset(fl4, 0, sizeof(*fl4));
 30	fl4->daddr = daddr->a4;
 31	fl4->flowi4_tos = tos;
 32	fl4->flowi4_oif = l3mdev_master_ifindex_by_index(net, oif);
 33	fl4->flowi4_mark = mark;
 34	if (saddr)
 35		fl4->saddr = saddr->a4;
 36
 37	fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF;
 38
 39	rt = __ip_route_output_key(net, fl4);
 40	if (!IS_ERR(rt))
 41		return &rt->dst;
 42
 43	return ERR_CAST(rt);
 44}
 45
 46static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
 47					  const xfrm_address_t *saddr,
 48					  const xfrm_address_t *daddr,
 49					  u32 mark)
 50{
 51	struct flowi4 fl4;
 52
 53	return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark);
 54}
 55
 56static int xfrm4_get_saddr(struct net *net, int oif,
 57			   xfrm_address_t *saddr, xfrm_address_t *daddr,
 58			   u32 mark)
 59{
 60	struct dst_entry *dst;
 61	struct flowi4 fl4;
 62
 63	dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark);
 64	if (IS_ERR(dst))
 65		return -EHOSTUNREACH;
 66
 67	saddr->a4 = fl4.saddr;
 68	dst_release(dst);
 69	return 0;
 70}
 71
 72static int xfrm4_get_tos(const struct flowi *fl)
 73{
 74	return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */
 75}
 76
 77static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst,
 78			   int nfheader_len)
 79{
 80	return 0;
 81}
 82
 83static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 84			  const struct flowi *fl)
 85{
 86	struct rtable *rt = (struct rtable *)xdst->route;
 87	const struct flowi4 *fl4 = &fl->u.ip4;
 88
 89	xdst->u.rt.rt_iif = fl4->flowi4_iif;
 90
 91	xdst->u.dst.dev = dev;
 92	dev_hold(dev);
 93
 94	/* Sheit... I remember I did this right. Apparently,
 95	 * it was magically lost, so this code needs audit */
 96	xdst->u.rt.rt_is_input = rt->rt_is_input;
 97	xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
 98					      RTCF_LOCAL);
 99	xdst->u.rt.rt_type = rt->rt_type;
100	xdst->u.rt.rt_gateway = rt->rt_gateway;
101	xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
102	xdst->u.rt.rt_pmtu = rt->rt_pmtu;
103	xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
104	INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
105	rt_add_uncached_list(&xdst->u.rt);
106
107	return 0;
108}
109
110static void
111_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
112{
113	const struct iphdr *iph = ip_hdr(skb);
114	u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
115	struct flowi4 *fl4 = &fl->u.ip4;
116	int oif = 0;
117
118	if (skb_dst(skb))
119		oif = skb_dst(skb)->dev->ifindex;
120
121	memset(fl4, 0, sizeof(struct flowi4));
122	fl4->flowi4_mark = skb->mark;
123	fl4->flowi4_oif = reverse ? skb->skb_iif : oif;
124
125	if (!ip_is_fragment(iph)) {
126		switch (iph->protocol) {
127		case IPPROTO_UDP:
128		case IPPROTO_UDPLITE:
129		case IPPROTO_TCP:
130		case IPPROTO_SCTP:
131		case IPPROTO_DCCP:
132			if (xprth + 4 < skb->data ||
133			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
134				__be16 *ports;
135
136				xprth = skb_network_header(skb) + iph->ihl * 4;
137				ports = (__be16 *)xprth;
138
139				fl4->fl4_sport = ports[!!reverse];
140				fl4->fl4_dport = ports[!reverse];
141			}
142			break;
143
144		case IPPROTO_ICMP:
145			if (xprth + 2 < skb->data ||
146			    pskb_may_pull(skb, xprth + 2 - skb->data)) {
147				u8 *icmp;
148
149				xprth = skb_network_header(skb) + iph->ihl * 4;
150				icmp = xprth;
151
152				fl4->fl4_icmp_type = icmp[0];
153				fl4->fl4_icmp_code = icmp[1];
154			}
155			break;
156
157		case IPPROTO_ESP:
158			if (xprth + 4 < skb->data ||
159			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
160				__be32 *ehdr;
161
162				xprth = skb_network_header(skb) + iph->ihl * 4;
163				ehdr = (__be32 *)xprth;
164
165				fl4->fl4_ipsec_spi = ehdr[0];
166			}
167			break;
168
169		case IPPROTO_AH:
170			if (xprth + 8 < skb->data ||
171			    pskb_may_pull(skb, xprth + 8 - skb->data)) {
172				__be32 *ah_hdr;
173
174				xprth = skb_network_header(skb) + iph->ihl * 4;
175				ah_hdr = (__be32 *)xprth;
176
177				fl4->fl4_ipsec_spi = ah_hdr[1];
178			}
179			break;
180
181		case IPPROTO_COMP:
182			if (xprth + 4 < skb->data ||
183			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
184				__be16 *ipcomp_hdr;
185
186				xprth = skb_network_header(skb) + iph->ihl * 4;
187				ipcomp_hdr = (__be16 *)xprth;
188
189				fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
190			}
191			break;
192
193		case IPPROTO_GRE:
194			if (xprth + 12 < skb->data ||
195			    pskb_may_pull(skb, xprth + 12 - skb->data)) {
196				__be16 *greflags;
197				__be32 *gre_hdr;
198
199				xprth = skb_network_header(skb) + iph->ihl * 4;
200				greflags = (__be16 *)xprth;
201				gre_hdr = (__be32 *)xprth;
202
203				if (greflags[0] & GRE_KEY) {
204					if (greflags[0] & GRE_CSUM)
205						gre_hdr++;
206					fl4->fl4_gre_key = gre_hdr[1];
207				}
208			}
209			break;
210
211		default:
212			fl4->fl4_ipsec_spi = 0;
213			break;
214		}
215	}
216	fl4->flowi4_proto = iph->protocol;
217	fl4->daddr = reverse ? iph->saddr : iph->daddr;
218	fl4->saddr = reverse ? iph->daddr : iph->saddr;
219	fl4->flowi4_tos = iph->tos;
220}
221
222static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
223			      struct sk_buff *skb, u32 mtu)
224{
225	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
226	struct dst_entry *path = xdst->route;
227
228	path->ops->update_pmtu(path, sk, skb, mtu);
229}
230
231static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
232			   struct sk_buff *skb)
233{
234	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
235	struct dst_entry *path = xdst->route;
236
237	path->ops->redirect(path, sk, skb);
238}
239
240static void xfrm4_dst_destroy(struct dst_entry *dst)
241{
242	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
243
244	dst_destroy_metrics_generic(dst);
245	if (xdst->u.rt.rt_uncached_list)
246		rt_del_uncached_list(&xdst->u.rt);
247	xfrm_dst_destroy(xdst);
248}
249
250static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
251			     int unregister)
252{
253	if (!unregister)
254		return;
255
256	xfrm_dst_ifdown(dst, dev);
257}
258
259static struct dst_ops xfrm4_dst_ops_template = {
260	.family =		AF_INET,
261	.update_pmtu =		xfrm4_update_pmtu,
262	.redirect =		xfrm4_redirect,
263	.cow_metrics =		dst_cow_metrics_generic,
264	.destroy =		xfrm4_dst_destroy,
265	.ifdown =		xfrm4_dst_ifdown,
266	.local_out =		__ip_local_out,
267	.gc_thresh =		32768,
268};
269
270static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
271	.dst_ops =		&xfrm4_dst_ops_template,
272	.dst_lookup =		xfrm4_dst_lookup,
273	.get_saddr =		xfrm4_get_saddr,
274	.decode_session =	_decode_session4,
275	.get_tos =		xfrm4_get_tos,
276	.init_path =		xfrm4_init_path,
277	.fill_dst =		xfrm4_fill_dst,
278	.blackhole_route =	ipv4_blackhole_route,
279};
280
281#ifdef CONFIG_SYSCTL
282static struct ctl_table xfrm4_policy_table[] = {
283	{
284		.procname       = "xfrm4_gc_thresh",
285		.data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
286		.maxlen         = sizeof(int),
287		.mode           = 0644,
288		.proc_handler   = proc_dointvec,
289	},
290	{ }
291};
292
293static __net_init int xfrm4_net_sysctl_init(struct net *net)
294{
295	struct ctl_table *table;
296	struct ctl_table_header *hdr;
297
298	table = xfrm4_policy_table;
299	if (!net_eq(net, &init_net)) {
300		table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
301		if (!table)
302			goto err_alloc;
303
304		table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
305	}
306
307	hdr = register_net_sysctl(net, "net/ipv4", table);
308	if (!hdr)
309		goto err_reg;
310
311	net->ipv4.xfrm4_hdr = hdr;
312	return 0;
313
314err_reg:
315	if (!net_eq(net, &init_net))
316		kfree(table);
317err_alloc:
318	return -ENOMEM;
319}
320
321static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
322{
323	struct ctl_table *table;
324
325	if (!net->ipv4.xfrm4_hdr)
326		return;
327
328	table = net->ipv4.xfrm4_hdr->ctl_table_arg;
329	unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
330	if (!net_eq(net, &init_net))
331		kfree(table);
332}
333#else /* CONFIG_SYSCTL */
334static inline int xfrm4_net_sysctl_init(struct net *net)
335{
336	return 0;
337}
338
339static inline void xfrm4_net_sysctl_exit(struct net *net)
340{
341}
342#endif
343
344static int __net_init xfrm4_net_init(struct net *net)
345{
346	int ret;
347
348	memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
349	       sizeof(xfrm4_dst_ops_template));
350	ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
351	if (ret)
352		return ret;
353
354	ret = xfrm4_net_sysctl_init(net);
355	if (ret)
356		dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
357
358	return ret;
359}
360
361static void __net_exit xfrm4_net_exit(struct net *net)
362{
363	xfrm4_net_sysctl_exit(net);
364	dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
365}
366
367static struct pernet_operations __net_initdata xfrm4_net_ops = {
368	.init	= xfrm4_net_init,
369	.exit	= xfrm4_net_exit,
370};
371
372static void __init xfrm4_policy_init(void)
373{
374	xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
375}
376
377void __init xfrm4_init(void)
378{
379	xfrm4_state_init();
380	xfrm4_policy_init();
381	xfrm4_protocol_init();
382	register_pernet_subsys(&xfrm4_net_ops);
383}