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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
39
40
41
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 if (dev)
53 dev_hold(dev);
54 dst->ops = ops;
55 dst_init_metrics(dst, dst_default_metrics.metrics, true);
56 dst->expires = 0UL;
57#ifdef CONFIG_XFRM
58 dst->xfrm = NULL;
59#endif
60 dst->input = dst_discard;
61 dst->output = dst_discard_out;
62 dst->error = 0;
63 dst->obsolete = initial_obsolete;
64 dst->header_len = 0;
65 dst->trailer_len = 0;
66#ifdef CONFIG_IP_ROUTE_CLASSID
67 dst->tclassid = 0;
68#endif
69 dst->lwtstate = NULL;
70 atomic_set(&dst->__refcnt, initial_ref);
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_ref, 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 if (ops->gc(ops)) {
88 pr_notice_ratelimited("Route cache is full: consider increasing sysctl net.ipv6.route.max_size.\n");
89 return NULL;
90 }
91 }
92
93 dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC);
94 if (!dst)
95 return NULL;
96
97 dst_init(dst, ops, dev, initial_ref, initial_obsolete, flags);
98
99 return dst;
100}
101EXPORT_SYMBOL(dst_alloc);
102
103struct dst_entry *dst_destroy(struct dst_entry * dst)
104{
105 struct dst_entry *child = NULL;
106
107 smp_rmb();
108
109#ifdef CONFIG_XFRM
110 if (dst->xfrm) {
111 struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
112
113 child = xdst->child;
114 }
115#endif
116 if (!(dst->flags & DST_NOCOUNT))
117 dst_entries_add(dst->ops, -1);
118
119 if (dst->ops->destroy)
120 dst->ops->destroy(dst);
121 if (dst->dev)
122 dev_put(dst->dev);
123
124 lwtstate_put(dst->lwtstate);
125
126 if (dst->flags & DST_METADATA)
127 metadata_dst_free((struct metadata_dst *)dst);
128 else
129 kmem_cache_free(dst->ops->kmem_cachep, dst);
130
131 dst = child;
132 if (dst)
133 dst_release_immediate(dst);
134 return NULL;
135}
136EXPORT_SYMBOL(dst_destroy);
137
138static void dst_destroy_rcu(struct rcu_head *head)
139{
140 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
141
142 dst = dst_destroy(dst);
143}
144
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151
152
153
154void dst_dev_put(struct dst_entry *dst)
155{
156 struct net_device *dev = dst->dev;
157
158 dst->obsolete = DST_OBSOLETE_DEAD;
159 if (dst->ops->ifdown)
160 dst->ops->ifdown(dst, dev, true);
161 dst->input = dst_discard;
162 dst->output = dst_discard_out;
163 dst->dev = blackhole_netdev;
164 dev_hold(dst->dev);
165 dev_put(dev);
166}
167EXPORT_SYMBOL(dst_dev_put);
168
169void dst_release(struct dst_entry *dst)
170{
171 if (dst) {
172 int newrefcnt;
173
174 newrefcnt = atomic_dec_return(&dst->__refcnt);
175 if (WARN_ONCE(newrefcnt < 0, "dst_release underflow"))
176 net_warn_ratelimited("%s: dst:%p refcnt:%d\n",
177 __func__, dst, newrefcnt);
178 if (!newrefcnt)
179 call_rcu(&dst->rcu_head, dst_destroy_rcu);
180 }
181}
182EXPORT_SYMBOL(dst_release);
183
184void dst_release_immediate(struct dst_entry *dst)
185{
186 if (dst) {
187 int newrefcnt;
188
189 newrefcnt = atomic_dec_return(&dst->__refcnt);
190 if (WARN_ONCE(newrefcnt < 0, "dst_release_immediate underflow"))
191 net_warn_ratelimited("%s: dst:%p refcnt:%d\n",
192 __func__, dst, newrefcnt);
193 if (!newrefcnt)
194 dst_destroy(dst);
195 }
196}
197EXPORT_SYMBOL(dst_release_immediate);
198
199u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
200{
201 struct dst_metrics *p = kmalloc(sizeof(*p), GFP_ATOMIC);
202
203 if (p) {
204 struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old);
205 unsigned long prev, new;
206
207 refcount_set(&p->refcnt, 1);
208 memcpy(p->metrics, old_p->metrics, sizeof(p->metrics));
209
210 new = (unsigned long) p;
211 prev = cmpxchg(&dst->_metrics, old, new);
212
213 if (prev != old) {
214 kfree(p);
215 p = (struct dst_metrics *)__DST_METRICS_PTR(prev);
216 if (prev & DST_METRICS_READ_ONLY)
217 p = NULL;
218 } else if (prev & DST_METRICS_REFCOUNTED) {
219 if (refcount_dec_and_test(&old_p->refcnt))
220 kfree(old_p);
221 }
222 }
223 BUILD_BUG_ON(offsetof(struct dst_metrics, metrics) != 0);
224 return (u32 *)p;
225}
226EXPORT_SYMBOL(dst_cow_metrics_generic);
227
228
229void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
230{
231 unsigned long prev, new;
232
233 new = ((unsigned long) &dst_default_metrics) | DST_METRICS_READ_ONLY;
234 prev = cmpxchg(&dst->_metrics, old, new);
235 if (prev == old)
236 kfree(__DST_METRICS_PTR(old));
237}
238EXPORT_SYMBOL(__dst_destroy_metrics_generic);
239
240struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie)
241{
242 return NULL;
243}
244
245u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old)
246{
247 return NULL;
248}
249
250struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,
251 struct sk_buff *skb,
252 const void *daddr)
253{
254 return NULL;
255}
256
257void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
258 struct sk_buff *skb, u32 mtu,
259 bool confirm_neigh)
260{
261}
262EXPORT_SYMBOL_GPL(dst_blackhole_update_pmtu);
263
264void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
265 struct sk_buff *skb)
266{
267}
268EXPORT_SYMBOL_GPL(dst_blackhole_redirect);
269
270unsigned int dst_blackhole_mtu(const struct dst_entry *dst)
271{
272 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
273
274 return mtu ? : dst->dev->mtu;
275}
276EXPORT_SYMBOL_GPL(dst_blackhole_mtu);
277
278static struct dst_ops dst_blackhole_ops = {
279 .family = AF_UNSPEC,
280 .neigh_lookup = dst_blackhole_neigh_lookup,
281 .check = dst_blackhole_check,
282 .cow_metrics = dst_blackhole_cow_metrics,
283 .update_pmtu = dst_blackhole_update_pmtu,
284 .redirect = dst_blackhole_redirect,
285 .mtu = dst_blackhole_mtu,
286};
287
288static void __metadata_dst_init(struct metadata_dst *md_dst,
289 enum metadata_type type, u8 optslen)
290{
291 struct dst_entry *dst;
292
293 dst = &md_dst->dst;
294 dst_init(dst, &dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE,
295 DST_METADATA | DST_NOCOUNT);
296 memset(dst + 1, 0, sizeof(*md_dst) + optslen - sizeof(*dst));
297 md_dst->type = type;
298}
299
300struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type,
301 gfp_t flags)
302{
303 struct metadata_dst *md_dst;
304
305 md_dst = kmalloc(sizeof(*md_dst) + optslen, flags);
306 if (!md_dst)
307 return NULL;
308
309 __metadata_dst_init(md_dst, type, optslen);
310
311 return md_dst;
312}
313EXPORT_SYMBOL_GPL(metadata_dst_alloc);
314
315void metadata_dst_free(struct metadata_dst *md_dst)
316{
317#ifdef CONFIG_DST_CACHE
318 if (md_dst->type == METADATA_IP_TUNNEL)
319 dst_cache_destroy(&md_dst->u.tun_info.dst_cache);
320#endif
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#ifdef CONFIG_DST_CACHE
346 int cpu;
347
348 for_each_possible_cpu(cpu) {
349 struct metadata_dst *one_md_dst = per_cpu_ptr(md_dst, cpu);
350
351 if (one_md_dst->type == METADATA_IP_TUNNEL)
352 dst_cache_destroy(&one_md_dst->u.tun_info.dst_cache);
353 }
354#endif
355 free_percpu(md_dst);
356}
357EXPORT_SYMBOL_GPL(metadata_dst_free_percpu);
358
