]> git.kernelconcepts.de Git - karo-tx-linux.git/blob - net/netfilter/nf_conntrack_ecache.c
xprtrdma: Rename rpcrdma_req::rl_free
[karo-tx-linux.git] / net / netfilter / nf_conntrack_ecache.c
1 /* Event cache for netfilter. */
2
3 /*
4  * (C) 2005 Harald Welte <laforge@gnumonks.org>
5  * (C) 2005 Patrick McHardy <kaber@trash.net>
6  * (C) 2005-2006 Netfilter Core Team <coreteam@netfilter.org>
7  * (C) 2005 USAGI/WIDE Project <http://www.linux-ipv6.org>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13
14 #include <linux/types.h>
15 #include <linux/netfilter.h>
16 #include <linux/skbuff.h>
17 #include <linux/vmalloc.h>
18 #include <linux/stddef.h>
19 #include <linux/err.h>
20 #include <linux/percpu.h>
21 #include <linux/kernel.h>
22 #include <linux/netdevice.h>
23 #include <linux/slab.h>
24 #include <linux/export.h>
25
26 #include <net/netfilter/nf_conntrack.h>
27 #include <net/netfilter/nf_conntrack_core.h>
28 #include <net/netfilter/nf_conntrack_extend.h>
29
30 static DEFINE_MUTEX(nf_ct_ecache_mutex);
31
32 #define ECACHE_RETRY_WAIT (HZ/10)
33
34 enum retry_state {
35         STATE_CONGESTED,
36         STATE_RESTART,
37         STATE_DONE,
38 };
39
40 static enum retry_state ecache_work_evict_list(struct ct_pcpu *pcpu)
41 {
42         struct nf_conn *refs[16];
43         struct nf_conntrack_tuple_hash *h;
44         struct hlist_nulls_node *n;
45         unsigned int evicted = 0;
46         enum retry_state ret = STATE_DONE;
47
48         spin_lock(&pcpu->lock);
49
50         hlist_nulls_for_each_entry(h, n, &pcpu->dying, hnnode) {
51                 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
52                 struct nf_conntrack_ecache *e;
53
54                 if (!nf_ct_is_confirmed(ct))
55                         continue;
56
57                 e = nf_ct_ecache_find(ct);
58                 if (!e || e->state != NFCT_ECACHE_DESTROY_FAIL)
59                         continue;
60
61                 if (nf_conntrack_event(IPCT_DESTROY, ct)) {
62                         ret = STATE_CONGESTED;
63                         break;
64                 }
65
66                 e->state = NFCT_ECACHE_DESTROY_SENT;
67                 refs[evicted] = ct;
68
69                 if (++evicted >= ARRAY_SIZE(refs)) {
70                         ret = STATE_RESTART;
71                         break;
72                 }
73         }
74
75         spin_unlock(&pcpu->lock);
76
77         /* can't _put while holding lock */
78         while (evicted)
79                 nf_ct_put(refs[--evicted]);
80
81         return ret;
82 }
83
84 static void ecache_work(struct work_struct *work)
85 {
86         struct netns_ct *ctnet =
87                 container_of(work, struct netns_ct, ecache_dwork.work);
88         int cpu, delay = -1;
89         struct ct_pcpu *pcpu;
90
91         local_bh_disable();
92
93         for_each_possible_cpu(cpu) {
94                 enum retry_state ret;
95
96                 pcpu = per_cpu_ptr(ctnet->pcpu_lists, cpu);
97
98                 ret = ecache_work_evict_list(pcpu);
99
100                 switch (ret) {
101                 case STATE_CONGESTED:
102                         delay = ECACHE_RETRY_WAIT;
103                         goto out;
104                 case STATE_RESTART:
105                         delay = 0;
106                         break;
107                 case STATE_DONE:
108                         break;
109                 }
110         }
111
112  out:
113         local_bh_enable();
114
115         ctnet->ecache_dwork_pending = delay > 0;
116         if (delay >= 0)
117                 schedule_delayed_work(&ctnet->ecache_dwork, delay);
118 }
119
120 int nf_conntrack_eventmask_report(unsigned int eventmask, struct nf_conn *ct,
121                                   u32 portid, int report)
122 {
123         int ret = 0;
124         struct net *net = nf_ct_net(ct);
125         struct nf_ct_event_notifier *notify;
126         struct nf_conntrack_ecache *e;
127
128         rcu_read_lock();
129         notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
130         if (!notify)
131                 goto out_unlock;
132
133         e = nf_ct_ecache_find(ct);
134         if (!e)
135                 goto out_unlock;
136
137         if (nf_ct_is_confirmed(ct)) {
138                 struct nf_ct_event item = {
139                         .ct     = ct,
140                         .portid = e->portid ? e->portid : portid,
141                         .report = report
142                 };
143                 /* This is a resent of a destroy event? If so, skip missed */
144                 unsigned long missed = e->portid ? 0 : e->missed;
145
146                 if (!((eventmask | missed) & e->ctmask))
147                         goto out_unlock;
148
149                 ret = notify->fcn(eventmask | missed, &item);
150                 if (unlikely(ret < 0 || missed)) {
151                         spin_lock_bh(&ct->lock);
152                         if (ret < 0) {
153                                 /* This is a destroy event that has been
154                                  * triggered by a process, we store the PORTID
155                                  * to include it in the retransmission.
156                                  */
157                                 if (eventmask & (1 << IPCT_DESTROY)) {
158                                         if (e->portid == 0 && portid != 0)
159                                                 e->portid = portid;
160                                         e->state = NFCT_ECACHE_DESTROY_FAIL;
161                                 } else {
162                                         e->missed |= eventmask;
163                                 }
164                         } else {
165                                 e->missed &= ~missed;
166                         }
167                         spin_unlock_bh(&ct->lock);
168                 }
169         }
170 out_unlock:
171         rcu_read_unlock();
172         return ret;
173 }
174 EXPORT_SYMBOL_GPL(nf_conntrack_eventmask_report);
175
176 /* deliver cached events and clear cache entry - must be called with locally
177  * disabled softirqs */
178 void nf_ct_deliver_cached_events(struct nf_conn *ct)
179 {
180         struct net *net = nf_ct_net(ct);
181         unsigned long events, missed;
182         struct nf_ct_event_notifier *notify;
183         struct nf_conntrack_ecache *e;
184         struct nf_ct_event item;
185         int ret;
186
187         rcu_read_lock();
188         notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
189         if (notify == NULL)
190                 goto out_unlock;
191
192         e = nf_ct_ecache_find(ct);
193         if (e == NULL)
194                 goto out_unlock;
195
196         events = xchg(&e->cache, 0);
197
198         if (!nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct))
199                 goto out_unlock;
200
201         /* We make a copy of the missed event cache without taking
202          * the lock, thus we may send missed events twice. However,
203          * this does not harm and it happens very rarely. */
204         missed = e->missed;
205
206         if (!((events | missed) & e->ctmask))
207                 goto out_unlock;
208
209         item.ct = ct;
210         item.portid = 0;
211         item.report = 0;
212
213         ret = notify->fcn(events | missed, &item);
214
215         if (likely(ret == 0 && !missed))
216                 goto out_unlock;
217
218         spin_lock_bh(&ct->lock);
219         if (ret < 0)
220                 e->missed |= events;
221         else
222                 e->missed &= ~missed;
223         spin_unlock_bh(&ct->lock);
224
225 out_unlock:
226         rcu_read_unlock();
227 }
228 EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events);
229
230 void nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
231                                struct nf_conntrack_expect *exp,
232                                u32 portid, int report)
233
234 {
235         struct net *net = nf_ct_exp_net(exp);
236         struct nf_exp_event_notifier *notify;
237         struct nf_conntrack_ecache *e;
238
239         rcu_read_lock();
240         notify = rcu_dereference(net->ct.nf_expect_event_cb);
241         if (!notify)
242                 goto out_unlock;
243
244         e = nf_ct_ecache_find(exp->master);
245         if (!e)
246                 goto out_unlock;
247
248         if (e->expmask & (1 << event)) {
249                 struct nf_exp_event item = {
250                         .exp    = exp,
251                         .portid = portid,
252                         .report = report
253                 };
254                 notify->fcn(1 << event, &item);
255         }
256 out_unlock:
257         rcu_read_unlock();
258 }
259
260 int nf_conntrack_register_notifier(struct net *net,
261                                    struct nf_ct_event_notifier *new)
262 {
263         int ret;
264         struct nf_ct_event_notifier *notify;
265
266         mutex_lock(&nf_ct_ecache_mutex);
267         notify = rcu_dereference_protected(net->ct.nf_conntrack_event_cb,
268                                            lockdep_is_held(&nf_ct_ecache_mutex));
269         if (notify != NULL) {
270                 ret = -EBUSY;
271                 goto out_unlock;
272         }
273         rcu_assign_pointer(net->ct.nf_conntrack_event_cb, new);
274         ret = 0;
275
276 out_unlock:
277         mutex_unlock(&nf_ct_ecache_mutex);
278         return ret;
279 }
280 EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier);
281
282 void nf_conntrack_unregister_notifier(struct net *net,
283                                       struct nf_ct_event_notifier *new)
284 {
285         struct nf_ct_event_notifier *notify;
286
287         mutex_lock(&nf_ct_ecache_mutex);
288         notify = rcu_dereference_protected(net->ct.nf_conntrack_event_cb,
289                                            lockdep_is_held(&nf_ct_ecache_mutex));
290         BUG_ON(notify != new);
291         RCU_INIT_POINTER(net->ct.nf_conntrack_event_cb, NULL);
292         mutex_unlock(&nf_ct_ecache_mutex);
293         /* synchronize_rcu() is called from ctnetlink_exit. */
294 }
295 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier);
296
297 int nf_ct_expect_register_notifier(struct net *net,
298                                    struct nf_exp_event_notifier *new)
299 {
300         int ret;
301         struct nf_exp_event_notifier *notify;
302
303         mutex_lock(&nf_ct_ecache_mutex);
304         notify = rcu_dereference_protected(net->ct.nf_expect_event_cb,
305                                            lockdep_is_held(&nf_ct_ecache_mutex));
306         if (notify != NULL) {
307                 ret = -EBUSY;
308                 goto out_unlock;
309         }
310         rcu_assign_pointer(net->ct.nf_expect_event_cb, new);
311         ret = 0;
312
313 out_unlock:
314         mutex_unlock(&nf_ct_ecache_mutex);
315         return ret;
316 }
317 EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier);
318
319 void nf_ct_expect_unregister_notifier(struct net *net,
320                                       struct nf_exp_event_notifier *new)
321 {
322         struct nf_exp_event_notifier *notify;
323
324         mutex_lock(&nf_ct_ecache_mutex);
325         notify = rcu_dereference_protected(net->ct.nf_expect_event_cb,
326                                            lockdep_is_held(&nf_ct_ecache_mutex));
327         BUG_ON(notify != new);
328         RCU_INIT_POINTER(net->ct.nf_expect_event_cb, NULL);
329         mutex_unlock(&nf_ct_ecache_mutex);
330         /* synchronize_rcu() is called from ctnetlink_exit. */
331 }
332 EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier);
333
334 #define NF_CT_EVENTS_DEFAULT 1
335 static int nf_ct_events __read_mostly = NF_CT_EVENTS_DEFAULT;
336
337 #ifdef CONFIG_SYSCTL
338 static struct ctl_table event_sysctl_table[] = {
339         {
340                 .procname       = "nf_conntrack_events",
341                 .data           = &init_net.ct.sysctl_events,
342                 .maxlen         = sizeof(unsigned int),
343                 .mode           = 0644,
344                 .proc_handler   = proc_dointvec,
345         },
346         {}
347 };
348 #endif /* CONFIG_SYSCTL */
349
350 static const struct nf_ct_ext_type event_extend = {
351         .len    = sizeof(struct nf_conntrack_ecache),
352         .align  = __alignof__(struct nf_conntrack_ecache),
353         .id     = NF_CT_EXT_ECACHE,
354 };
355
356 #ifdef CONFIG_SYSCTL
357 static int nf_conntrack_event_init_sysctl(struct net *net)
358 {
359         struct ctl_table *table;
360
361         table = kmemdup(event_sysctl_table, sizeof(event_sysctl_table),
362                         GFP_KERNEL);
363         if (!table)
364                 goto out;
365
366         table[0].data = &net->ct.sysctl_events;
367
368         /* Don't export sysctls to unprivileged users */
369         if (net->user_ns != &init_user_ns)
370                 table[0].procname = NULL;
371
372         net->ct.event_sysctl_header =
373                 register_net_sysctl(net, "net/netfilter", table);
374         if (!net->ct.event_sysctl_header) {
375                 printk(KERN_ERR "nf_ct_event: can't register to sysctl.\n");
376                 goto out_register;
377         }
378         return 0;
379
380 out_register:
381         kfree(table);
382 out:
383         return -ENOMEM;
384 }
385
386 static void nf_conntrack_event_fini_sysctl(struct net *net)
387 {
388         struct ctl_table *table;
389
390         table = net->ct.event_sysctl_header->ctl_table_arg;
391         unregister_net_sysctl_table(net->ct.event_sysctl_header);
392         kfree(table);
393 }
394 #else
395 static int nf_conntrack_event_init_sysctl(struct net *net)
396 {
397         return 0;
398 }
399
400 static void nf_conntrack_event_fini_sysctl(struct net *net)
401 {
402 }
403 #endif /* CONFIG_SYSCTL */
404
405 int nf_conntrack_ecache_pernet_init(struct net *net)
406 {
407         net->ct.sysctl_events = nf_ct_events;
408         INIT_DELAYED_WORK(&net->ct.ecache_dwork, ecache_work);
409         return nf_conntrack_event_init_sysctl(net);
410 }
411
412 void nf_conntrack_ecache_pernet_fini(struct net *net)
413 {
414         cancel_delayed_work_sync(&net->ct.ecache_dwork);
415         nf_conntrack_event_fini_sysctl(net);
416 }
417
418 int nf_conntrack_ecache_init(void)
419 {
420         int ret = nf_ct_extend_register(&event_extend);
421         if (ret < 0)
422                 pr_err("nf_ct_event: Unable to register event extension.\n");
423
424         BUILD_BUG_ON(__IPCT_MAX >= 16); /* ctmask, missed use u16 */
425
426         return ret;
427 }
428
429 void nf_conntrack_ecache_fini(void)
430 {
431         nf_ct_extend_unregister(&event_extend);
432 }