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[deliverable/linux.git] / net / netfilter / nf_log.c
1 #include <linux/kernel.h>
2 #include <linux/init.h>
3 #include <linux/module.h>
4 #include <linux/proc_fs.h>
5 #include <linux/skbuff.h>
6 #include <linux/netfilter.h>
7 #include <linux/seq_file.h>
8 #include <net/protocol.h>
9 #include <net/netfilter/nf_log.h>
10
11 #include "nf_internals.h"
12
13 /* Internal logging interface, which relies on the real
14 LOG target modules */
15
16 #define NF_LOG_PREFIXLEN 128
17 #define NFLOGGER_NAME_LEN 64
18
19 static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;
20 static DEFINE_MUTEX(nf_log_mutex);
21
22 #define nft_log_dereference(logger) \
23 rcu_dereference_protected(logger, lockdep_is_held(&nf_log_mutex))
24
25 static struct nf_logger *__find_logger(int pf, const char *str_logger)
26 {
27 struct nf_logger *log;
28 int i;
29
30 for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
31 if (loggers[pf][i] == NULL)
32 continue;
33
34 log = nft_log_dereference(loggers[pf][i]);
35 if (!strncasecmp(str_logger, log->name, strlen(log->name)))
36 return log;
37 }
38
39 return NULL;
40 }
41
42 int nf_log_set(struct net *net, u_int8_t pf, const struct nf_logger *logger)
43 {
44 const struct nf_logger *log;
45
46 if (pf == NFPROTO_UNSPEC || pf >= ARRAY_SIZE(net->nf.nf_loggers))
47 return -EOPNOTSUPP;
48
49 mutex_lock(&nf_log_mutex);
50 log = nft_log_dereference(net->nf.nf_loggers[pf]);
51 if (log == NULL)
52 rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
53
54 mutex_unlock(&nf_log_mutex);
55
56 return 0;
57 }
58 EXPORT_SYMBOL(nf_log_set);
59
60 void nf_log_unset(struct net *net, const struct nf_logger *logger)
61 {
62 int i;
63 const struct nf_logger *log;
64
65 mutex_lock(&nf_log_mutex);
66 for (i = 0; i < NFPROTO_NUMPROTO; i++) {
67 log = nft_log_dereference(net->nf.nf_loggers[i]);
68 if (log == logger)
69 RCU_INIT_POINTER(net->nf.nf_loggers[i], NULL);
70 }
71 mutex_unlock(&nf_log_mutex);
72 synchronize_rcu();
73 }
74 EXPORT_SYMBOL(nf_log_unset);
75
76 /* return EEXIST if the same logger is registered, 0 on success. */
77 int nf_log_register(u_int8_t pf, struct nf_logger *logger)
78 {
79 int i;
80 int ret = 0;
81
82 if (pf >= ARRAY_SIZE(init_net.nf.nf_loggers))
83 return -EINVAL;
84
85 mutex_lock(&nf_log_mutex);
86
87 if (pf == NFPROTO_UNSPEC) {
88 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
89 if (rcu_access_pointer(loggers[i][logger->type])) {
90 ret = -EEXIST;
91 goto unlock;
92 }
93 }
94 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
95 rcu_assign_pointer(loggers[i][logger->type], logger);
96 } else {
97 if (rcu_access_pointer(loggers[pf][logger->type])) {
98 ret = -EEXIST;
99 goto unlock;
100 }
101 rcu_assign_pointer(loggers[pf][logger->type], logger);
102 }
103
104 unlock:
105 mutex_unlock(&nf_log_mutex);
106 return ret;
107 }
108 EXPORT_SYMBOL(nf_log_register);
109
110 void nf_log_unregister(struct nf_logger *logger)
111 {
112 const struct nf_logger *log;
113 int i;
114
115 mutex_lock(&nf_log_mutex);
116 for (i = 0; i < NFPROTO_NUMPROTO; i++) {
117 log = nft_log_dereference(loggers[i][logger->type]);
118 if (log == logger)
119 RCU_INIT_POINTER(loggers[i][logger->type], NULL);
120 }
121 mutex_unlock(&nf_log_mutex);
122 synchronize_rcu();
123 }
124 EXPORT_SYMBOL(nf_log_unregister);
125
126 int nf_log_bind_pf(struct net *net, u_int8_t pf,
127 const struct nf_logger *logger)
128 {
129 if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
130 return -EINVAL;
131 mutex_lock(&nf_log_mutex);
132 if (__find_logger(pf, logger->name) == NULL) {
133 mutex_unlock(&nf_log_mutex);
134 return -ENOENT;
135 }
136 rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
137 mutex_unlock(&nf_log_mutex);
138 return 0;
139 }
140 EXPORT_SYMBOL(nf_log_bind_pf);
141
142 void nf_log_unbind_pf(struct net *net, u_int8_t pf)
143 {
144 if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
145 return;
146 mutex_lock(&nf_log_mutex);
147 RCU_INIT_POINTER(net->nf.nf_loggers[pf], NULL);
148 mutex_unlock(&nf_log_mutex);
149 }
150 EXPORT_SYMBOL(nf_log_unbind_pf);
151
152 void nf_logger_request_module(int pf, enum nf_log_type type)
153 {
154 if (loggers[pf][type] == NULL)
155 request_module("nf-logger-%u-%u", pf, type);
156 }
157 EXPORT_SYMBOL_GPL(nf_logger_request_module);
158
159 int nf_logger_find_get(int pf, enum nf_log_type type)
160 {
161 struct nf_logger *logger;
162 int ret = -ENOENT;
163
164 if (pf == NFPROTO_INET) {
165 ret = nf_logger_find_get(NFPROTO_IPV4, type);
166 if (ret < 0)
167 return ret;
168
169 ret = nf_logger_find_get(NFPROTO_IPV6, type);
170 if (ret < 0) {
171 nf_logger_put(NFPROTO_IPV4, type);
172 return ret;
173 }
174
175 return 0;
176 }
177
178 if (rcu_access_pointer(loggers[pf][type]) == NULL)
179 request_module("nf-logger-%u-%u", pf, type);
180
181 rcu_read_lock();
182 logger = rcu_dereference(loggers[pf][type]);
183 if (logger == NULL)
184 goto out;
185
186 if (try_module_get(logger->me))
187 ret = 0;
188 out:
189 rcu_read_unlock();
190 return ret;
191 }
192 EXPORT_SYMBOL_GPL(nf_logger_find_get);
193
194 void nf_logger_put(int pf, enum nf_log_type type)
195 {
196 struct nf_logger *logger;
197
198 if (pf == NFPROTO_INET) {
199 nf_logger_put(NFPROTO_IPV4, type);
200 nf_logger_put(NFPROTO_IPV6, type);
201 return;
202 }
203
204 BUG_ON(loggers[pf][type] == NULL);
205
206 rcu_read_lock();
207 logger = rcu_dereference(loggers[pf][type]);
208 module_put(logger->me);
209 rcu_read_unlock();
210 }
211 EXPORT_SYMBOL_GPL(nf_logger_put);
212
213 void nf_log_packet(struct net *net,
214 u_int8_t pf,
215 unsigned int hooknum,
216 const struct sk_buff *skb,
217 const struct net_device *in,
218 const struct net_device *out,
219 const struct nf_loginfo *loginfo,
220 const char *fmt, ...)
221 {
222 va_list args;
223 char prefix[NF_LOG_PREFIXLEN];
224 const struct nf_logger *logger;
225
226 rcu_read_lock();
227 if (loginfo != NULL)
228 logger = rcu_dereference(loggers[pf][loginfo->type]);
229 else
230 logger = rcu_dereference(net->nf.nf_loggers[pf]);
231
232 if (logger) {
233 va_start(args, fmt);
234 vsnprintf(prefix, sizeof(prefix), fmt, args);
235 va_end(args);
236 logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
237 }
238 rcu_read_unlock();
239 }
240 EXPORT_SYMBOL(nf_log_packet);
241
242 void nf_log_trace(struct net *net,
243 u_int8_t pf,
244 unsigned int hooknum,
245 const struct sk_buff *skb,
246 const struct net_device *in,
247 const struct net_device *out,
248 const struct nf_loginfo *loginfo, const char *fmt, ...)
249 {
250 va_list args;
251 char prefix[NF_LOG_PREFIXLEN];
252 const struct nf_logger *logger;
253
254 rcu_read_lock();
255 logger = rcu_dereference(net->nf.nf_loggers[pf]);
256 if (logger) {
257 va_start(args, fmt);
258 vsnprintf(prefix, sizeof(prefix), fmt, args);
259 va_end(args);
260 logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
261 }
262 rcu_read_unlock();
263 }
264 EXPORT_SYMBOL(nf_log_trace);
265
266 #define S_SIZE (1024 - (sizeof(unsigned int) + 1))
267
268 struct nf_log_buf {
269 unsigned int count;
270 char buf[S_SIZE + 1];
271 };
272 static struct nf_log_buf emergency, *emergency_ptr = &emergency;
273
274 __printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...)
275 {
276 va_list args;
277 int len;
278
279 if (likely(m->count < S_SIZE)) {
280 va_start(args, f);
281 len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
282 va_end(args);
283 if (likely(m->count + len < S_SIZE)) {
284 m->count += len;
285 return 0;
286 }
287 }
288 m->count = S_SIZE;
289 printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
290 return -1;
291 }
292 EXPORT_SYMBOL_GPL(nf_log_buf_add);
293
294 struct nf_log_buf *nf_log_buf_open(void)
295 {
296 struct nf_log_buf *m = kmalloc(sizeof(*m), GFP_ATOMIC);
297
298 if (unlikely(!m)) {
299 local_bh_disable();
300 do {
301 m = xchg(&emergency_ptr, NULL);
302 } while (!m);
303 }
304 m->count = 0;
305 return m;
306 }
307 EXPORT_SYMBOL_GPL(nf_log_buf_open);
308
309 void nf_log_buf_close(struct nf_log_buf *m)
310 {
311 m->buf[m->count] = 0;
312 printk("%s\n", m->buf);
313
314 if (likely(m != &emergency))
315 kfree(m);
316 else {
317 emergency_ptr = m;
318 local_bh_enable();
319 }
320 }
321 EXPORT_SYMBOL_GPL(nf_log_buf_close);
322
323 #ifdef CONFIG_PROC_FS
324 static void *seq_start(struct seq_file *seq, loff_t *pos)
325 {
326 struct net *net = seq_file_net(seq);
327
328 mutex_lock(&nf_log_mutex);
329
330 if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
331 return NULL;
332
333 return pos;
334 }
335
336 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
337 {
338 struct net *net = seq_file_net(s);
339
340 (*pos)++;
341
342 if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
343 return NULL;
344
345 return pos;
346 }
347
348 static void seq_stop(struct seq_file *s, void *v)
349 {
350 mutex_unlock(&nf_log_mutex);
351 }
352
353 static int seq_show(struct seq_file *s, void *v)
354 {
355 loff_t *pos = v;
356 const struct nf_logger *logger;
357 int i;
358 struct net *net = seq_file_net(s);
359
360 logger = nft_log_dereference(net->nf.nf_loggers[*pos]);
361
362 if (!logger)
363 seq_printf(s, "%2lld NONE (", *pos);
364 else
365 seq_printf(s, "%2lld %s (", *pos, logger->name);
366
367 if (seq_has_overflowed(s))
368 return -ENOSPC;
369
370 for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
371 if (loggers[*pos][i] == NULL)
372 continue;
373
374 logger = nft_log_dereference(loggers[*pos][i]);
375 seq_printf(s, "%s", logger->name);
376 if (i == 0 && loggers[*pos][i + 1] != NULL)
377 seq_printf(s, ",");
378
379 if (seq_has_overflowed(s))
380 return -ENOSPC;
381 }
382
383 seq_printf(s, ")\n");
384
385 if (seq_has_overflowed(s))
386 return -ENOSPC;
387 return 0;
388 }
389
390 static const struct seq_operations nflog_seq_ops = {
391 .start = seq_start,
392 .next = seq_next,
393 .stop = seq_stop,
394 .show = seq_show,
395 };
396
397 static int nflog_open(struct inode *inode, struct file *file)
398 {
399 return seq_open_net(inode, file, &nflog_seq_ops,
400 sizeof(struct seq_net_private));
401 }
402
403 static const struct file_operations nflog_file_ops = {
404 .owner = THIS_MODULE,
405 .open = nflog_open,
406 .read = seq_read,
407 .llseek = seq_lseek,
408 .release = seq_release_net,
409 };
410
411
412 #endif /* PROC_FS */
413
414 #ifdef CONFIG_SYSCTL
415 static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
416 static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
417
418 static int nf_log_proc_dostring(struct ctl_table *table, int write,
419 void __user *buffer, size_t *lenp, loff_t *ppos)
420 {
421 const struct nf_logger *logger;
422 char buf[NFLOGGER_NAME_LEN];
423 int r = 0;
424 int tindex = (unsigned long)table->extra1;
425 struct net *net = current->nsproxy->net_ns;
426
427 if (write) {
428 struct ctl_table tmp = *table;
429
430 tmp.data = buf;
431 r = proc_dostring(&tmp, write, buffer, lenp, ppos);
432 if (r)
433 return r;
434
435 if (!strcmp(buf, "NONE")) {
436 nf_log_unbind_pf(net, tindex);
437 return 0;
438 }
439 mutex_lock(&nf_log_mutex);
440 logger = __find_logger(tindex, buf);
441 if (logger == NULL) {
442 mutex_unlock(&nf_log_mutex);
443 return -ENOENT;
444 }
445 rcu_assign_pointer(net->nf.nf_loggers[tindex], logger);
446 mutex_unlock(&nf_log_mutex);
447 } else {
448 mutex_lock(&nf_log_mutex);
449 logger = nft_log_dereference(net->nf.nf_loggers[tindex]);
450 if (!logger)
451 table->data = "NONE";
452 else
453 table->data = logger->name;
454 r = proc_dostring(table, write, buffer, lenp, ppos);
455 mutex_unlock(&nf_log_mutex);
456 }
457
458 return r;
459 }
460
461 static int netfilter_log_sysctl_init(struct net *net)
462 {
463 int i;
464 struct ctl_table *table;
465
466 table = nf_log_sysctl_table;
467 if (!net_eq(net, &init_net)) {
468 table = kmemdup(nf_log_sysctl_table,
469 sizeof(nf_log_sysctl_table),
470 GFP_KERNEL);
471 if (!table)
472 goto err_alloc;
473 } else {
474 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
475 snprintf(nf_log_sysctl_fnames[i],
476 3, "%d", i);
477 nf_log_sysctl_table[i].procname =
478 nf_log_sysctl_fnames[i];
479 nf_log_sysctl_table[i].data = NULL;
480 nf_log_sysctl_table[i].maxlen = NFLOGGER_NAME_LEN;
481 nf_log_sysctl_table[i].mode = 0644;
482 nf_log_sysctl_table[i].proc_handler =
483 nf_log_proc_dostring;
484 nf_log_sysctl_table[i].extra1 =
485 (void *)(unsigned long) i;
486 }
487 }
488
489 net->nf.nf_log_dir_header = register_net_sysctl(net,
490 "net/netfilter/nf_log",
491 table);
492 if (!net->nf.nf_log_dir_header)
493 goto err_reg;
494
495 return 0;
496
497 err_reg:
498 if (!net_eq(net, &init_net))
499 kfree(table);
500 err_alloc:
501 return -ENOMEM;
502 }
503
504 static void netfilter_log_sysctl_exit(struct net *net)
505 {
506 struct ctl_table *table;
507
508 table = net->nf.nf_log_dir_header->ctl_table_arg;
509 unregister_net_sysctl_table(net->nf.nf_log_dir_header);
510 if (!net_eq(net, &init_net))
511 kfree(table);
512 }
513 #else
514 static int netfilter_log_sysctl_init(struct net *net)
515 {
516 return 0;
517 }
518
519 static void netfilter_log_sysctl_exit(struct net *net)
520 {
521 }
522 #endif /* CONFIG_SYSCTL */
523
524 static int __net_init nf_log_net_init(struct net *net)
525 {
526 int ret = -ENOMEM;
527
528 #ifdef CONFIG_PROC_FS
529 if (!proc_create("nf_log", S_IRUGO,
530 net->nf.proc_netfilter, &nflog_file_ops))
531 return ret;
532 #endif
533 ret = netfilter_log_sysctl_init(net);
534 if (ret < 0)
535 goto out_sysctl;
536
537 return 0;
538
539 out_sysctl:
540 #ifdef CONFIG_PROC_FS
541 remove_proc_entry("nf_log", net->nf.proc_netfilter);
542 #endif
543 return ret;
544 }
545
546 static void __net_exit nf_log_net_exit(struct net *net)
547 {
548 netfilter_log_sysctl_exit(net);
549 #ifdef CONFIG_PROC_FS
550 remove_proc_entry("nf_log", net->nf.proc_netfilter);
551 #endif
552 }
553
554 static struct pernet_operations nf_log_net_ops = {
555 .init = nf_log_net_init,
556 .exit = nf_log_net_exit,
557 };
558
559 int __init netfilter_log_init(void)
560 {
561 return register_pernet_subsys(&nf_log_net_ops);
562 }
Linux kernel - Deliverables
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