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v6.8
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * net/core/dst.c	Protocol independent destination cache.
  4 *
  5 * Authors:		Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  6 *
  7 */
  8
  9#include <linux/bitops.h>
 10#include <linux/errno.h>
 11#include <linux/init.h>
 12#include <linux/kernel.h>
 13#include <linux/workqueue.h>
 14#include <linux/mm.h>
 15#include <linux/module.h>
 16#include <linux/slab.h>
 17#include <linux/netdevice.h>
 18#include <linux/skbuff.h>
 19#include <linux/string.h>
 20#include <linux/types.h>
 21#include <net/net_namespace.h>
 22#include <linux/sched.h>
 23#include <linux/prefetch.h>
 24#include <net/lwtunnel.h>
 25#include <net/xfrm.h>
 26
 27#include <net/dst.h>
 28#include <net/dst_metadata.h>
 29
 30int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 31{
 32	kfree_skb(skb);
 33	return 0;
 34}
 35EXPORT_SYMBOL(dst_discard_out);
 36
 37const struct dst_metrics dst_default_metrics = {
 38	/* This initializer is needed to force linker to place this variable
 39	 * into const section. Otherwise it might end into bss section.
 40	 * We really want to avoid false sharing on this variable, and catch
 41	 * any writes on it.
 42	 */
 43	.refcnt = REFCOUNT_INIT(1),
 44};
 45EXPORT_SYMBOL(dst_default_metrics);
 46
 47void dst_init(struct dst_entry *dst, struct dst_ops *ops,
 48	      struct net_device *dev, int initial_obsolete,
 49	      unsigned short flags)
 50{
 51	dst->dev = dev;
 52	netdev_hold(dev, &dst->dev_tracker, GFP_ATOMIC);
 53	dst->ops = ops;
 54	dst_init_metrics(dst, dst_default_metrics.metrics, true);
 55	dst->expires = 0UL;
 56#ifdef CONFIG_XFRM
 57	dst->xfrm = NULL;
 58#endif
 59	dst->input = dst_discard;
 60	dst->output = dst_discard_out;
 61	dst->error = 0;
 62	dst->obsolete = initial_obsolete;
 63	dst->header_len = 0;
 64	dst->trailer_len = 0;
 65#ifdef CONFIG_IP_ROUTE_CLASSID
 66	dst->tclassid = 0;
 67#endif
 68	dst->lwtstate = NULL;
 69	rcuref_init(&dst->__rcuref, 1);
 70	INIT_LIST_HEAD(&dst->rt_uncached);
 71	dst->__use = 0;
 72	dst->lastuse = jiffies;
 73	dst->flags = flags;
 74	if (!(flags & DST_NOCOUNT))
 75		dst_entries_add(ops, 1);
 76}
 77EXPORT_SYMBOL(dst_init);
 78
 79void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
 80		int initial_obsolete, unsigned short flags)
 81{
 82	struct dst_entry *dst;
 83
 84	if (ops->gc &&
 85	    !(flags & DST_NOCOUNT) &&
 86	    dst_entries_get_fast(ops) > ops->gc_thresh)
 87		ops->gc(ops);
 
 
 
 
 88
 89	dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC);
 90	if (!dst)
 91		return NULL;
 92
 93	dst_init(dst, ops, dev, initial_obsolete, flags);
 94
 95	return dst;
 96}
 97EXPORT_SYMBOL(dst_alloc);
 98
 99struct dst_entry *dst_destroy(struct dst_entry * dst)
100{
101	struct dst_entry *child = NULL;
102
103	smp_rmb();
104
105#ifdef CONFIG_XFRM
106	if (dst->xfrm) {
107		struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
108
109		child = xdst->child;
110	}
111#endif
112	if (!(dst->flags & DST_NOCOUNT))
113		dst_entries_add(dst->ops, -1);
114
115	if (dst->ops->destroy)
116		dst->ops->destroy(dst);
117	netdev_put(dst->dev, &dst->dev_tracker);
118
119	lwtstate_put(dst->lwtstate);
120
121	if (dst->flags & DST_METADATA)
122		metadata_dst_free((struct metadata_dst *)dst);
123	else
124		kmem_cache_free(dst->ops->kmem_cachep, dst);
125
126	dst = child;
127	if (dst)
128		dst_release_immediate(dst);
129	return NULL;
130}
131EXPORT_SYMBOL(dst_destroy);
132
133static void dst_destroy_rcu(struct rcu_head *head)
134{
135	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
136
137	dst = dst_destroy(dst);
138}
139
140/* Operations to mark dst as DEAD and clean up the net device referenced
141 * by dst:
142 * 1. put the dst under blackhole interface and discard all tx/rx packets
143 *    on this route.
144 * 2. release the net_device
145 * This function should be called when removing routes from the fib tree
146 * in preparation for a NETDEV_DOWN/NETDEV_UNREGISTER event and also to
147 * make the next dst_ops->check() fail.
148 */
149void dst_dev_put(struct dst_entry *dst)
150{
151	struct net_device *dev = dst->dev;
152
153	dst->obsolete = DST_OBSOLETE_DEAD;
154	if (dst->ops->ifdown)
155		dst->ops->ifdown(dst, dev);
156	dst->input = dst_discard;
157	dst->output = dst_discard_out;
158	dst->dev = blackhole_netdev;
159	netdev_ref_replace(dev, blackhole_netdev, &dst->dev_tracker,
160			   GFP_ATOMIC);
161}
162EXPORT_SYMBOL(dst_dev_put);
163
164void dst_release(struct dst_entry *dst)
165{
166	if (dst && rcuref_put(&dst->__rcuref))
167		call_rcu_hurry(&dst->rcu_head, dst_destroy_rcu);
 
 
 
 
 
 
 
 
168}
169EXPORT_SYMBOL(dst_release);
170
171void dst_release_immediate(struct dst_entry *dst)
172{
173	if (dst && rcuref_put(&dst->__rcuref))
174		dst_destroy(dst);
 
 
 
 
 
 
 
 
175}
176EXPORT_SYMBOL(dst_release_immediate);
177
178u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
179{
180	struct dst_metrics *p = kmalloc(sizeof(*p), GFP_ATOMIC);
181
182	if (p) {
183		struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old);
184		unsigned long prev, new;
185
186		refcount_set(&p->refcnt, 1);
187		memcpy(p->metrics, old_p->metrics, sizeof(p->metrics));
188
189		new = (unsigned long) p;
190		prev = cmpxchg(&dst->_metrics, old, new);
191
192		if (prev != old) {
193			kfree(p);
194			p = (struct dst_metrics *)__DST_METRICS_PTR(prev);
195			if (prev & DST_METRICS_READ_ONLY)
196				p = NULL;
197		} else if (prev & DST_METRICS_REFCOUNTED) {
198			if (refcount_dec_and_test(&old_p->refcnt))
199				kfree(old_p);
200		}
201	}
202	BUILD_BUG_ON(offsetof(struct dst_metrics, metrics) != 0);
203	return (u32 *)p;
204}
205EXPORT_SYMBOL(dst_cow_metrics_generic);
206
207/* Caller asserts that dst_metrics_read_only(dst) is false.  */
208void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
209{
210	unsigned long prev, new;
211
212	new = ((unsigned long) &dst_default_metrics) | DST_METRICS_READ_ONLY;
213	prev = cmpxchg(&dst->_metrics, old, new);
214	if (prev == old)
215		kfree(__DST_METRICS_PTR(old));
216}
217EXPORT_SYMBOL(__dst_destroy_metrics_generic);
218
219struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie)
220{
221	return NULL;
222}
223
224u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old)
225{
226	return NULL;
227}
228
229struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,
230					     struct sk_buff *skb,
231					     const void *daddr)
232{
233	return NULL;
234}
235
236void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
237			       struct sk_buff *skb, u32 mtu,
238			       bool confirm_neigh)
239{
240}
241EXPORT_SYMBOL_GPL(dst_blackhole_update_pmtu);
242
243void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
244			    struct sk_buff *skb)
245{
246}
247EXPORT_SYMBOL_GPL(dst_blackhole_redirect);
248
249unsigned int dst_blackhole_mtu(const struct dst_entry *dst)
250{
251	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
252
253	return mtu ? : dst->dev->mtu;
254}
255EXPORT_SYMBOL_GPL(dst_blackhole_mtu);
256
257static struct dst_ops dst_blackhole_ops = {
258	.family		= AF_UNSPEC,
259	.neigh_lookup	= dst_blackhole_neigh_lookup,
260	.check		= dst_blackhole_check,
261	.cow_metrics	= dst_blackhole_cow_metrics,
262	.update_pmtu	= dst_blackhole_update_pmtu,
263	.redirect	= dst_blackhole_redirect,
264	.mtu		= dst_blackhole_mtu,
265};
266
267static void __metadata_dst_init(struct metadata_dst *md_dst,
268				enum metadata_type type, u8 optslen)
269{
270	struct dst_entry *dst;
271
272	dst = &md_dst->dst;
273	dst_init(dst, &dst_blackhole_ops, NULL, DST_OBSOLETE_NONE,
274		 DST_METADATA | DST_NOCOUNT);
275	memset(dst + 1, 0, sizeof(*md_dst) + optslen - sizeof(*dst));
276	md_dst->type = type;
277}
278
279struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type,
280					gfp_t flags)
281{
282	struct metadata_dst *md_dst;
283
284	md_dst = kmalloc(sizeof(*md_dst) + optslen, flags);
285	if (!md_dst)
286		return NULL;
287
288	__metadata_dst_init(md_dst, type, optslen);
289
290	return md_dst;
291}
292EXPORT_SYMBOL_GPL(metadata_dst_alloc);
293
294void metadata_dst_free(struct metadata_dst *md_dst)
295{
296#ifdef CONFIG_DST_CACHE
297	if (md_dst->type == METADATA_IP_TUNNEL)
298		dst_cache_destroy(&md_dst->u.tun_info.dst_cache);
299#endif
300	if (md_dst->type == METADATA_XFRM)
301		dst_release(md_dst->u.xfrm_info.dst_orig);
302	kfree(md_dst);
303}
304EXPORT_SYMBOL_GPL(metadata_dst_free);
305
306struct metadata_dst __percpu *
307metadata_dst_alloc_percpu(u8 optslen, enum metadata_type type, gfp_t flags)
308{
309	int cpu;
310	struct metadata_dst __percpu *md_dst;
311
312	md_dst = __alloc_percpu_gfp(sizeof(struct metadata_dst) + optslen,
313				    __alignof__(struct metadata_dst), flags);
314	if (!md_dst)
315		return NULL;
316
317	for_each_possible_cpu(cpu)
318		__metadata_dst_init(per_cpu_ptr(md_dst, cpu), type, optslen);
319
320	return md_dst;
321}
322EXPORT_SYMBOL_GPL(metadata_dst_alloc_percpu);
323
324void metadata_dst_free_percpu(struct metadata_dst __percpu *md_dst)
325{
326	int cpu;
327
328	for_each_possible_cpu(cpu) {
329		struct metadata_dst *one_md_dst = per_cpu_ptr(md_dst, cpu);
330
331#ifdef CONFIG_DST_CACHE
332		if (one_md_dst->type == METADATA_IP_TUNNEL)
333			dst_cache_destroy(&one_md_dst->u.tun_info.dst_cache);
334#endif
335		if (one_md_dst->type == METADATA_XFRM)
336			dst_release(one_md_dst->u.xfrm_info.dst_orig);
337	}
338	free_percpu(md_dst);
339}
340EXPORT_SYMBOL_GPL(metadata_dst_free_percpu);
v6.2
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * net/core/dst.c	Protocol independent destination cache.
  4 *
  5 * Authors:		Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  6 *
  7 */
  8
  9#include <linux/bitops.h>
 10#include <linux/errno.h>
 11#include <linux/init.h>
 12#include <linux/kernel.h>
 13#include <linux/workqueue.h>
 14#include <linux/mm.h>
 15#include <linux/module.h>
 16#include <linux/slab.h>
 17#include <linux/netdevice.h>
 18#include <linux/skbuff.h>
 19#include <linux/string.h>
 20#include <linux/types.h>
 21#include <net/net_namespace.h>
 22#include <linux/sched.h>
 23#include <linux/prefetch.h>
 24#include <net/lwtunnel.h>
 25#include <net/xfrm.h>
 26
 27#include <net/dst.h>
 28#include <net/dst_metadata.h>
 29
 30int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 31{
 32	kfree_skb(skb);
 33	return 0;
 34}
 35EXPORT_SYMBOL(dst_discard_out);
 36
 37const struct dst_metrics dst_default_metrics = {
 38	/* This initializer is needed to force linker to place this variable
 39	 * into const section. Otherwise it might end into bss section.
 40	 * We really want to avoid false sharing on this variable, and catch
 41	 * any writes on it.
 42	 */
 43	.refcnt = REFCOUNT_INIT(1),
 44};
 45EXPORT_SYMBOL(dst_default_metrics);
 46
 47void dst_init(struct dst_entry *dst, struct dst_ops *ops,
 48	      struct net_device *dev, int initial_ref, int initial_obsolete,
 49	      unsigned short flags)
 50{
 51	dst->dev = dev;
 52	netdev_hold(dev, &dst->dev_tracker, GFP_ATOMIC);
 53	dst->ops = ops;
 54	dst_init_metrics(dst, dst_default_metrics.metrics, true);
 55	dst->expires = 0UL;
 56#ifdef CONFIG_XFRM
 57	dst->xfrm = NULL;
 58#endif
 59	dst->input = dst_discard;
 60	dst->output = dst_discard_out;
 61	dst->error = 0;
 62	dst->obsolete = initial_obsolete;
 63	dst->header_len = 0;
 64	dst->trailer_len = 0;
 65#ifdef CONFIG_IP_ROUTE_CLASSID
 66	dst->tclassid = 0;
 67#endif
 68	dst->lwtstate = NULL;
 69	atomic_set(&dst->__refcnt, initial_ref);
 
 70	dst->__use = 0;
 71	dst->lastuse = jiffies;
 72	dst->flags = flags;
 73	if (!(flags & DST_NOCOUNT))
 74		dst_entries_add(ops, 1);
 75}
 76EXPORT_SYMBOL(dst_init);
 77
 78void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
 79		int initial_ref, int initial_obsolete, unsigned short flags)
 80{
 81	struct dst_entry *dst;
 82
 83	if (ops->gc &&
 84	    !(flags & DST_NOCOUNT) &&
 85	    dst_entries_get_fast(ops) > ops->gc_thresh) {
 86		if (ops->gc(ops)) {
 87			pr_notice_ratelimited("Route cache is full: consider increasing sysctl net.ipv6.route.max_size.\n");
 88			return NULL;
 89		}
 90	}
 91
 92	dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC);
 93	if (!dst)
 94		return NULL;
 95
 96	dst_init(dst, ops, dev, initial_ref, initial_obsolete, flags);
 97
 98	return dst;
 99}
100EXPORT_SYMBOL(dst_alloc);
101
102struct dst_entry *dst_destroy(struct dst_entry * dst)
103{
104	struct dst_entry *child = NULL;
105
106	smp_rmb();
107
108#ifdef CONFIG_XFRM
109	if (dst->xfrm) {
110		struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
111
112		child = xdst->child;
113	}
114#endif
115	if (!(dst->flags & DST_NOCOUNT))
116		dst_entries_add(dst->ops, -1);
117
118	if (dst->ops->destroy)
119		dst->ops->destroy(dst);
120	netdev_put(dst->dev, &dst->dev_tracker);
121
122	lwtstate_put(dst->lwtstate);
123
124	if (dst->flags & DST_METADATA)
125		metadata_dst_free((struct metadata_dst *)dst);
126	else
127		kmem_cache_free(dst->ops->kmem_cachep, dst);
128
129	dst = child;
130	if (dst)
131		dst_release_immediate(dst);
132	return NULL;
133}
134EXPORT_SYMBOL(dst_destroy);
135
136static void dst_destroy_rcu(struct rcu_head *head)
137{
138	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
139
140	dst = dst_destroy(dst);
141}
142
143/* Operations to mark dst as DEAD and clean up the net device referenced
144 * by dst:
145 * 1. put the dst under blackhole interface and discard all tx/rx packets
146 *    on this route.
147 * 2. release the net_device
148 * This function should be called when removing routes from the fib tree
149 * in preparation for a NETDEV_DOWN/NETDEV_UNREGISTER event and also to
150 * make the next dst_ops->check() fail.
151 */
152void dst_dev_put(struct dst_entry *dst)
153{
154	struct net_device *dev = dst->dev;
155
156	dst->obsolete = DST_OBSOLETE_DEAD;
157	if (dst->ops->ifdown)
158		dst->ops->ifdown(dst, dev, true);
159	dst->input = dst_discard;
160	dst->output = dst_discard_out;
161	dst->dev = blackhole_netdev;
162	netdev_ref_replace(dev, blackhole_netdev, &dst->dev_tracker,
163			   GFP_ATOMIC);
164}
165EXPORT_SYMBOL(dst_dev_put);
166
167void dst_release(struct dst_entry *dst)
168{
169	if (dst) {
170		int newrefcnt;
171
172		newrefcnt = atomic_dec_return(&dst->__refcnt);
173		if (WARN_ONCE(newrefcnt < 0, "dst_release underflow"))
174			net_warn_ratelimited("%s: dst:%p refcnt:%d\n",
175					     __func__, dst, newrefcnt);
176		if (!newrefcnt)
177			call_rcu_hurry(&dst->rcu_head, dst_destroy_rcu);
178	}
179}
180EXPORT_SYMBOL(dst_release);
181
182void dst_release_immediate(struct dst_entry *dst)
183{
184	if (dst) {
185		int newrefcnt;
186
187		newrefcnt = atomic_dec_return(&dst->__refcnt);
188		if (WARN_ONCE(newrefcnt < 0, "dst_release_immediate underflow"))
189			net_warn_ratelimited("%s: dst:%p refcnt:%d\n",
190					     __func__, dst, newrefcnt);
191		if (!newrefcnt)
192			dst_destroy(dst);
193	}
194}
195EXPORT_SYMBOL(dst_release_immediate);
196
197u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
198{
199	struct dst_metrics *p = kmalloc(sizeof(*p), GFP_ATOMIC);
200
201	if (p) {
202		struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old);
203		unsigned long prev, new;
204
205		refcount_set(&p->refcnt, 1);
206		memcpy(p->metrics, old_p->metrics, sizeof(p->metrics));
207
208		new = (unsigned long) p;
209		prev = cmpxchg(&dst->_metrics, old, new);
210
211		if (prev != old) {
212			kfree(p);
213			p = (struct dst_metrics *)__DST_METRICS_PTR(prev);
214			if (prev & DST_METRICS_READ_ONLY)
215				p = NULL;
216		} else if (prev & DST_METRICS_REFCOUNTED) {
217			if (refcount_dec_and_test(&old_p->refcnt))
218				kfree(old_p);
219		}
220	}
221	BUILD_BUG_ON(offsetof(struct dst_metrics, metrics) != 0);
222	return (u32 *)p;
223}
224EXPORT_SYMBOL(dst_cow_metrics_generic);
225
226/* Caller asserts that dst_metrics_read_only(dst) is false.  */
227void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
228{
229	unsigned long prev, new;
230
231	new = ((unsigned long) &dst_default_metrics) | DST_METRICS_READ_ONLY;
232	prev = cmpxchg(&dst->_metrics, old, new);
233	if (prev == old)
234		kfree(__DST_METRICS_PTR(old));
235}
236EXPORT_SYMBOL(__dst_destroy_metrics_generic);
237
238struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie)
239{
240	return NULL;
241}
242
243u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old)
244{
245	return NULL;
246}
247
248struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,
249					     struct sk_buff *skb,
250					     const void *daddr)
251{
252	return NULL;
253}
254
255void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
256			       struct sk_buff *skb, u32 mtu,
257			       bool confirm_neigh)
258{
259}
260EXPORT_SYMBOL_GPL(dst_blackhole_update_pmtu);
261
262void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
263			    struct sk_buff *skb)
264{
265}
266EXPORT_SYMBOL_GPL(dst_blackhole_redirect);
267
268unsigned int dst_blackhole_mtu(const struct dst_entry *dst)
269{
270	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
271
272	return mtu ? : dst->dev->mtu;
273}
274EXPORT_SYMBOL_GPL(dst_blackhole_mtu);
275
276static struct dst_ops dst_blackhole_ops = {
277	.family		= AF_UNSPEC,
278	.neigh_lookup	= dst_blackhole_neigh_lookup,
279	.check		= dst_blackhole_check,
280	.cow_metrics	= dst_blackhole_cow_metrics,
281	.update_pmtu	= dst_blackhole_update_pmtu,
282	.redirect	= dst_blackhole_redirect,
283	.mtu		= dst_blackhole_mtu,
284};
285
286static void __metadata_dst_init(struct metadata_dst *md_dst,
287				enum metadata_type type, u8 optslen)
288{
289	struct dst_entry *dst;
290
291	dst = &md_dst->dst;
292	dst_init(dst, &dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE,
293		 DST_METADATA | DST_NOCOUNT);
294	memset(dst + 1, 0, sizeof(*md_dst) + optslen - sizeof(*dst));
295	md_dst->type = type;
296}
297
298struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type,
299					gfp_t flags)
300{
301	struct metadata_dst *md_dst;
302
303	md_dst = kmalloc(sizeof(*md_dst) + optslen, flags);
304	if (!md_dst)
305		return NULL;
306
307	__metadata_dst_init(md_dst, type, optslen);
308
309	return md_dst;
310}
311EXPORT_SYMBOL_GPL(metadata_dst_alloc);
312
313void metadata_dst_free(struct metadata_dst *md_dst)
314{
315#ifdef CONFIG_DST_CACHE
316	if (md_dst->type == METADATA_IP_TUNNEL)
317		dst_cache_destroy(&md_dst->u.tun_info.dst_cache);
318#endif
319	if (md_dst->type == METADATA_XFRM)
320		dst_release(md_dst->u.xfrm_info.dst_orig);
321	kfree(md_dst);
322}
323EXPORT_SYMBOL_GPL(metadata_dst_free);
324
325struct metadata_dst __percpu *
326metadata_dst_alloc_percpu(u8 optslen, enum metadata_type type, gfp_t flags)
327{
328	int cpu;
329	struct metadata_dst __percpu *md_dst;
330
331	md_dst = __alloc_percpu_gfp(sizeof(struct metadata_dst) + optslen,
332				    __alignof__(struct metadata_dst), flags);
333	if (!md_dst)
334		return NULL;
335
336	for_each_possible_cpu(cpu)
337		__metadata_dst_init(per_cpu_ptr(md_dst, cpu), type, optslen);
338
339	return md_dst;
340}
341EXPORT_SYMBOL_GPL(metadata_dst_alloc_percpu);
342
343void metadata_dst_free_percpu(struct metadata_dst __percpu *md_dst)
344{
345	int cpu;
346
347	for_each_possible_cpu(cpu) {
348		struct metadata_dst *one_md_dst = per_cpu_ptr(md_dst, cpu);
349
350#ifdef CONFIG_DST_CACHE
351		if (one_md_dst->type == METADATA_IP_TUNNEL)
352			dst_cache_destroy(&one_md_dst->u.tun_info.dst_cache);
353#endif
354		if (one_md_dst->type == METADATA_XFRM)
355			dst_release(one_md_dst->u.xfrm_info.dst_orig);
356	}
357	free_percpu(md_dst);
358}
359EXPORT_SYMBOL_GPL(metadata_dst_free_percpu);