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TOMOYO Linux Cross Reference
Linux/net/netfilter/nf_log.c

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

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