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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
30static DEFINE_MUTEX(nf_ct_ecache_mutex);
31
32#define ECACHE_RETRY_WAIT (HZ/10)
33
34enum retry_state {
35 STATE_CONGESTED,
36 STATE_RESTART,
37 STATE_DONE,
38};
39
40static 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
53 if (nf_ct_is_dying(ct))
54 continue;
55
56 if (nf_conntrack_event(IPCT_DESTROY, ct)) {
57 ret = STATE_CONGESTED;
58 break;
59 }
60
61
62 set_bit(IPS_DYING_BIT, &ct->status);
63 refs[evicted] = ct;
64
65 if (++evicted >= ARRAY_SIZE(refs)) {
66 ret = STATE_RESTART;
67 break;
68 }
69 }
70
71 spin_unlock(&pcpu->lock);
72
73
74 while (evicted)
75 nf_ct_put(refs[--evicted]);
76
77 return ret;
78}
79
80static void ecache_work(struct work_struct *work)
81{
82 struct netns_ct *ctnet =
83 container_of(work, struct netns_ct, ecache_dwork.work);
84 int cpu, delay = -1;
85 struct ct_pcpu *pcpu;
86
87 local_bh_disable();
88
89 for_each_possible_cpu(cpu) {
90 enum retry_state ret;
91
92 pcpu = per_cpu_ptr(ctnet->pcpu_lists, cpu);
93
94 ret = ecache_work_evict_list(pcpu);
95
96 switch (ret) {
97 case STATE_CONGESTED:
98 delay = ECACHE_RETRY_WAIT;
99 goto out;
100 case STATE_RESTART:
101 delay = 0;
102 break;
103 case STATE_DONE:
104 break;
105 }
106 }
107
108 out:
109 local_bh_enable();
110
111 ctnet->ecache_dwork_pending = delay > 0;
112 if (delay >= 0)
113 schedule_delayed_work(&ctnet->ecache_dwork, delay);
114}
115
116int nf_conntrack_eventmask_report(unsigned int eventmask, struct nf_conn *ct,
117 u32 portid, int report)
118{
119 int ret = 0;
120 struct net *net = nf_ct_net(ct);
121 struct nf_ct_event_notifier *notify;
122 struct nf_conntrack_ecache *e;
123
124 rcu_read_lock();
125 notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
126 if (!notify)
127 goto out_unlock;
128
129 e = nf_ct_ecache_find(ct);
130 if (!e)
131 goto out_unlock;
132
133 if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct)) {
134 struct nf_ct_event item = {
135 .ct = ct,
136 .portid = e->portid ? e->portid : portid,
137 .report = report
138 };
139
140 unsigned long missed = e->portid ? 0 : e->missed;
141
142 if (!((eventmask | missed) & e->ctmask))
143 goto out_unlock;
144
145 ret = notify->fcn(eventmask | missed, &item);
146 if (unlikely(ret < 0 || missed)) {
147 spin_lock_bh(&ct->lock);
148 if (ret < 0) {
149
150
151
152
153 if (eventmask & (1 << IPCT_DESTROY) &&
154 e->portid == 0 && portid != 0)
155 e->portid = portid;
156 else
157 e->missed |= eventmask;
158 } else {
159 e->missed &= ~missed;
160 }
161 spin_unlock_bh(&ct->lock);
162 }
163 }
164out_unlock:
165 rcu_read_unlock();
166 return ret;
167}
168EXPORT_SYMBOL_GPL(nf_conntrack_eventmask_report);
169
170
171
172void nf_ct_deliver_cached_events(struct nf_conn *ct)
173{
174 struct net *net = nf_ct_net(ct);
175 unsigned long events, missed;
176 struct nf_ct_event_notifier *notify;
177 struct nf_conntrack_ecache *e;
178 struct nf_ct_event item;
179 int ret;
180
181 rcu_read_lock();
182 notify = rcu_dereference(net->ct.nf_conntrack_event_cb);
183 if (notify == NULL)
184 goto out_unlock;
185
186 e = nf_ct_ecache_find(ct);
187 if (e == NULL)
188 goto out_unlock;
189
190 events = xchg(&e->cache, 0);
191
192 if (!nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct) || !events)
193 goto out_unlock;
194
195
196
197
198 missed = e->missed;
199
200 if (!((events | missed) & e->ctmask))
201 goto out_unlock;
202
203 item.ct = ct;
204 item.portid = 0;
205 item.report = 0;
206
207 ret = notify->fcn(events | missed, &item);
208
209 if (likely(ret >= 0 && !missed))
210 goto out_unlock;
211
212 spin_lock_bh(&ct->lock);
213 if (ret < 0)
214 e->missed |= events;
215 else
216 e->missed &= ~missed;
217 spin_unlock_bh(&ct->lock);
218
219out_unlock:
220 rcu_read_unlock();
221}
222EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events);
223
224void nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
225 struct nf_conntrack_expect *exp,
226 u32 portid, int report)
227
228{
229 struct net *net = nf_ct_exp_net(exp);
230 struct nf_exp_event_notifier *notify;
231 struct nf_conntrack_ecache *e;
232
233 rcu_read_lock();
234 notify = rcu_dereference(net->ct.nf_expect_event_cb);
235 if (!notify)
236 goto out_unlock;
237
238 e = nf_ct_ecache_find(exp->master);
239 if (!e)
240 goto out_unlock;
241
242 if (e->expmask & (1 << event)) {
243 struct nf_exp_event item = {
244 .exp = exp,
245 .portid = portid,
246 .report = report
247 };
248 notify->fcn(1 << event, &item);
249 }
250out_unlock:
251 rcu_read_unlock();
252}
253
254int nf_conntrack_register_notifier(struct net *net,
255 struct nf_ct_event_notifier *new)
256{
257 int ret;
258 struct nf_ct_event_notifier *notify;
259
260 mutex_lock(&nf_ct_ecache_mutex);
261 notify = rcu_dereference_protected(net->ct.nf_conntrack_event_cb,
262 lockdep_is_held(&nf_ct_ecache_mutex));
263 if (notify != NULL) {
264 ret = -EBUSY;
265 goto out_unlock;
266 }
267 rcu_assign_pointer(net->ct.nf_conntrack_event_cb, new);
268 ret = 0;
269
270out_unlock:
271 mutex_unlock(&nf_ct_ecache_mutex);
272 return ret;
273}
274EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier);
275
276void nf_conntrack_unregister_notifier(struct net *net,
277 struct nf_ct_event_notifier *new)
278{
279 struct nf_ct_event_notifier *notify;
280
281 mutex_lock(&nf_ct_ecache_mutex);
282 notify = rcu_dereference_protected(net->ct.nf_conntrack_event_cb,
283 lockdep_is_held(&nf_ct_ecache_mutex));
284 BUG_ON(notify != new);
285 RCU_INIT_POINTER(net->ct.nf_conntrack_event_cb, NULL);
286 mutex_unlock(&nf_ct_ecache_mutex);
287}
288EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier);
289
290int nf_ct_expect_register_notifier(struct net *net,
291 struct nf_exp_event_notifier *new)
292{
293 int ret;
294 struct nf_exp_event_notifier *notify;
295
296 mutex_lock(&nf_ct_ecache_mutex);
297 notify = rcu_dereference_protected(net->ct.nf_expect_event_cb,
298 lockdep_is_held(&nf_ct_ecache_mutex));
299 if (notify != NULL) {
300 ret = -EBUSY;
301 goto out_unlock;
302 }
303 rcu_assign_pointer(net->ct.nf_expect_event_cb, new);
304 ret = 0;
305
306out_unlock:
307 mutex_unlock(&nf_ct_ecache_mutex);
308 return ret;
309}
310EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier);
311
312void nf_ct_expect_unregister_notifier(struct net *net,
313 struct nf_exp_event_notifier *new)
314{
315 struct nf_exp_event_notifier *notify;
316
317 mutex_lock(&nf_ct_ecache_mutex);
318 notify = rcu_dereference_protected(net->ct.nf_expect_event_cb,
319 lockdep_is_held(&nf_ct_ecache_mutex));
320 BUG_ON(notify != new);
321 RCU_INIT_POINTER(net->ct.nf_expect_event_cb, NULL);
322 mutex_unlock(&nf_ct_ecache_mutex);
323}
324EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier);
325
326#define NF_CT_EVENTS_DEFAULT 1
327static int nf_ct_events __read_mostly = NF_CT_EVENTS_DEFAULT;
328
329#ifdef CONFIG_SYSCTL
330static struct ctl_table event_sysctl_table[] = {
331 {
332 .procname = "nf_conntrack_events",
333 .data = &init_net.ct.sysctl_events,
334 .maxlen = sizeof(unsigned int),
335 .mode = 0644,
336 .proc_handler = proc_dointvec,
337 },
338 {}
339};
340#endif
341
342static struct nf_ct_ext_type event_extend __read_mostly = {
343 .len = sizeof(struct nf_conntrack_ecache),
344 .align = __alignof__(struct nf_conntrack_ecache),
345 .id = NF_CT_EXT_ECACHE,
346};
347
348#ifdef CONFIG_SYSCTL
349static int nf_conntrack_event_init_sysctl(struct net *net)
350{
351 struct ctl_table *table;
352
353 table = kmemdup(event_sysctl_table, sizeof(event_sysctl_table),
354 GFP_KERNEL);
355 if (!table)
356 goto out;
357
358 table[0].data = &net->ct.sysctl_events;
359
360
361 if (net->user_ns != &init_user_ns)
362 table[0].procname = NULL;
363
364 net->ct.event_sysctl_header =
365 register_net_sysctl(net, "net/netfilter", table);
366 if (!net->ct.event_sysctl_header) {
367 printk(KERN_ERR "nf_ct_event: can't register to sysctl.\n");
368 goto out_register;
369 }
370 return 0;
371
372out_register:
373 kfree(table);
374out:
375 return -ENOMEM;
376}
377
378static void nf_conntrack_event_fini_sysctl(struct net *net)
379{
380 struct ctl_table *table;
381
382 table = net->ct.event_sysctl_header->ctl_table_arg;
383 unregister_net_sysctl_table(net->ct.event_sysctl_header);
384 kfree(table);
385}
386#else
387static int nf_conntrack_event_init_sysctl(struct net *net)
388{
389 return 0;
390}
391
392static void nf_conntrack_event_fini_sysctl(struct net *net)
393{
394}
395#endif
396
397int nf_conntrack_ecache_pernet_init(struct net *net)
398{
399 net->ct.sysctl_events = nf_ct_events;
400 INIT_DELAYED_WORK(&net->ct.ecache_dwork, ecache_work);
401 return nf_conntrack_event_init_sysctl(net);
402}
403
404void nf_conntrack_ecache_pernet_fini(struct net *net)
405{
406 cancel_delayed_work_sync(&net->ct.ecache_dwork);
407 nf_conntrack_event_fini_sysctl(net);
408}
409
410int nf_conntrack_ecache_init(void)
411{
412 int ret = nf_ct_extend_register(&event_extend);
413 if (ret < 0)
414 pr_err("nf_ct_event: Unable to register event extension.\n");
415 return ret;
416}
417
418void nf_conntrack_ecache_fini(void)
419{
420 nf_ct_extend_unregister(&event_extend);
421}
422
