Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <linux/seq_file.h>
#include <net/protocol.h>
#include <net/netfilter/nf_log.h>

#include "nf_internals.h"

/* Internal logging interface, which relies on the real
   LOG target modules */

#define NF_LOG_PREFIXLEN		128
#define NFLOGGER_NAME_LEN		64

static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;
static DEFINE_MUTEX(nf_log_mutex);

#define nft_log_dereference(logger) \
	rcu_dereference_protected(logger, lockdep_is_held(&nf_log_mutex))

static struct nf_logger *__find_logger(int pf, const char *str_logger)
{
	struct nf_logger *log;
	int i;

	for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
		if (loggers[pf][i] == NULL)
			continue;

		log = nft_log_dereference(loggers[pf][i]);
		if (!strncasecmp(str_logger, log->name, strlen(log->name)))
			return log;
	}

	return NULL;
}

void nf_log_set(struct net *net, u_int8_t pf, const struct nf_logger *logger)
{
	const struct nf_logger *log;

	if (pf == NFPROTO_UNSPEC)
		return;

	mutex_lock(&nf_log_mutex);
	log = nft_log_dereference(net->nf.nf_loggers[pf]);
	if (log == NULL)
		rcu_assign_pointer(net->nf.nf_loggers[pf], logger);

	mutex_unlock(&nf_log_mutex);
}
EXPORT_SYMBOL(nf_log_set);

void nf_log_unset(struct net *net, const struct nf_logger *logger)
{
	int i;
	const struct nf_logger *log;

	mutex_lock(&nf_log_mutex);
	for (i = 0; i < NFPROTO_NUMPROTO; i++) {
		log = nft_log_dereference(net->nf.nf_loggers[i]);
		if (log == logger)
			RCU_INIT_POINTER(net->nf.nf_loggers[i], NULL);
	}
	mutex_unlock(&nf_log_mutex);
	synchronize_rcu();
}
EXPORT_SYMBOL(nf_log_unset);

/* return EEXIST if the same logger is registered, 0 on success. */
int nf_log_register(u_int8_t pf, struct nf_logger *logger)
{
	int i;
	int ret = 0;

	if (pf >= ARRAY_SIZE(init_net.nf.nf_loggers))
		return -EINVAL;

	mutex_lock(&nf_log_mutex);

	if (pf == NFPROTO_UNSPEC) {
		for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
			if (rcu_access_pointer(loggers[i][logger->type])) {
				ret = -EEXIST;
				goto unlock;
			}
		}
		for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
			rcu_assign_pointer(loggers[i][logger->type], logger);
	} else {
		if (rcu_access_pointer(loggers[pf][logger->type])) {
			ret = -EEXIST;
			goto unlock;
		}
		rcu_assign_pointer(loggers[pf][logger->type], logger);
	}

unlock:
	mutex_unlock(&nf_log_mutex);
	return ret;
}
EXPORT_SYMBOL(nf_log_register);

void nf_log_unregister(struct nf_logger *logger)
{
	int i;

	mutex_lock(&nf_log_mutex);
	for (i = 0; i < NFPROTO_NUMPROTO; i++)
		RCU_INIT_POINTER(loggers[i][logger->type], NULL);
	mutex_unlock(&nf_log_mutex);
}
EXPORT_SYMBOL(nf_log_unregister);

int nf_log_bind_pf(struct net *net, u_int8_t pf,
		   const struct nf_logger *logger)
{
	if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
		return -EINVAL;
	mutex_lock(&nf_log_mutex);
	if (__find_logger(pf, logger->name) == NULL) {
		mutex_unlock(&nf_log_mutex);
		return -ENOENT;
	}
	rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
	mutex_unlock(&nf_log_mutex);
	return 0;
}
EXPORT_SYMBOL(nf_log_bind_pf);

void nf_log_unbind_pf(struct net *net, u_int8_t pf)
{
	if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
		return;
	mutex_lock(&nf_log_mutex);
	RCU_INIT_POINTER(net->nf.nf_loggers[pf], NULL);
	mutex_unlock(&nf_log_mutex);
}
EXPORT_SYMBOL(nf_log_unbind_pf);

void nf_logger_request_module(int pf, enum nf_log_type type)
{
	if (loggers[pf][type] == NULL)
		request_module("nf-logger-%u-%u", pf, type);
}
EXPORT_SYMBOL_GPL(nf_logger_request_module);

int nf_logger_find_get(int pf, enum nf_log_type type)
{
	struct nf_logger *logger;
	int ret = -ENOENT;

	if (rcu_access_pointer(loggers[pf][type]) == NULL)
		request_module("nf-logger-%u-%u", pf, type);

	rcu_read_lock();
	logger = rcu_dereference(loggers[pf][type]);
	if (logger == NULL)
		goto out;

	if (logger && try_module_get(logger->me))
		ret = 0;
out:
	rcu_read_unlock();
	return ret;
}
EXPORT_SYMBOL_GPL(nf_logger_find_get);

void nf_logger_put(int pf, enum nf_log_type type)
{
	struct nf_logger *logger;

	BUG_ON(loggers[pf][type] == NULL);

	rcu_read_lock();
	logger = rcu_dereference(loggers[pf][type]);
	module_put(logger->me);
	rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(nf_logger_put);

void nf_log_packet(struct net *net,
		   u_int8_t pf,
		   unsigned int hooknum,
		   const struct sk_buff *skb,
		   const struct net_device *in,
		   const struct net_device *out,
		   const struct nf_loginfo *loginfo,
		   const char *fmt, ...)
{
	va_list args;
	char prefix[NF_LOG_PREFIXLEN];
	const struct nf_logger *logger;

	rcu_read_lock();
	if (loginfo != NULL)
		logger = rcu_dereference(loggers[pf][loginfo->type]);
	else
		logger = rcu_dereference(net->nf.nf_loggers[pf]);

	if (logger) {
		va_start(args, fmt);
		vsnprintf(prefix, sizeof(prefix), fmt, args);
		va_end(args);
		logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
	}
	rcu_read_unlock();
}
EXPORT_SYMBOL(nf_log_packet);

void nf_log_trace(struct net *net,
		  u_int8_t pf,
		  unsigned int hooknum,
		  const struct sk_buff *skb,
		  const struct net_device *in,
		  const struct net_device *out,
		  const struct nf_loginfo *loginfo, const char *fmt, ...)
{
	va_list args;
	char prefix[NF_LOG_PREFIXLEN];
	const struct nf_logger *logger;

	rcu_read_lock();
	logger = rcu_dereference(net->nf.nf_loggers[pf]);
	if (logger) {
		va_start(args, fmt);
		vsnprintf(prefix, sizeof(prefix), fmt, args);
		va_end(args);
		logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
	}
	rcu_read_unlock();
}
EXPORT_SYMBOL(nf_log_trace);

#define S_SIZE (1024 - (sizeof(unsigned int) + 1))

struct nf_log_buf {
	unsigned int	count;
	char		buf[S_SIZE + 1];
};
static struct nf_log_buf emergency, *emergency_ptr = &emergency;

__printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...)
{
	va_list args;
	int len;

	if (likely(m->count < S_SIZE)) {
		va_start(args, f);
		len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
		va_end(args);
		if (likely(m->count + len < S_SIZE)) {
			m->count += len;
			return 0;
		}
	}
	m->count = S_SIZE;
	printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
	return -1;
}
EXPORT_SYMBOL_GPL(nf_log_buf_add);

struct nf_log_buf *nf_log_buf_open(void)
{
	struct nf_log_buf *m = kmalloc(sizeof(*m), GFP_ATOMIC);

	if (unlikely(!m)) {
		local_bh_disable();
		do {
			m = xchg(&emergency_ptr, NULL);
		} while (!m);
	}
	m->count = 0;
	return m;
}
EXPORT_SYMBOL_GPL(nf_log_buf_open);

void nf_log_buf_close(struct nf_log_buf *m)
{
	m->buf[m->count] = 0;
	printk("%s\n", m->buf);

	if (likely(m != &emergency))
		kfree(m);
	else {
		emergency_ptr = m;
		local_bh_enable();
	}
}
EXPORT_SYMBOL_GPL(nf_log_buf_close);

#ifdef CONFIG_PROC_FS
static void *seq_start(struct seq_file *seq, loff_t *pos)
{
	struct net *net = seq_file_net(seq);

	mutex_lock(&nf_log_mutex);

	if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
		return NULL;

	return pos;
}

static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
{
	struct net *net = seq_file_net(s);

	(*pos)++;

	if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
		return NULL;

	return pos;
}

static void seq_stop(struct seq_file *s, void *v)
{
	mutex_unlock(&nf_log_mutex);
}

static int seq_show(struct seq_file *s, void *v)
{
	loff_t *pos = v;
	const struct nf_logger *logger;
	int i;
	struct net *net = seq_file_net(s);

	logger = nft_log_dereference(net->nf.nf_loggers[*pos]);

	if (!logger)
		seq_printf(s, "%2lld NONE (", *pos);
	else
		seq_printf(s, "%2lld %s (", *pos, logger->name);

	if (seq_has_overflowed(s))
		return -ENOSPC;

	for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
		if (loggers[*pos][i] == NULL)
			continue;

		logger = nft_log_dereference(loggers[*pos][i]);
		seq_printf(s, "%s", logger->name);
		if (i == 0 && loggers[*pos][i + 1] != NULL)
			seq_printf(s, ",");

		if (seq_has_overflowed(s))
			return -ENOSPC;
	}

	seq_printf(s, ")\n");

	if (seq_has_overflowed(s))
		return -ENOSPC;
	return 0;
}

static const struct seq_operations nflog_seq_ops = {
	.start	= seq_start,
	.next	= seq_next,
	.stop	= seq_stop,
	.show	= seq_show,
};

static int nflog_open(struct inode *inode, struct file *file)
{
	return seq_open_net(inode, file, &nflog_seq_ops,
			    sizeof(struct seq_net_private));
}

static const struct file_operations nflog_file_ops = {
	.owner	 = THIS_MODULE,
	.open	 = nflog_open,
	.read	 = seq_read,
	.llseek	 = seq_lseek,
	.release = seq_release_net,
};


#endif /* PROC_FS */

#ifdef CONFIG_SYSCTL
static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];

static int nf_log_proc_dostring(struct ctl_table *table, int write,
			 void __user *buffer, size_t *lenp, loff_t *ppos)
{
	const struct nf_logger *logger;
	char buf[NFLOGGER_NAME_LEN];
	size_t size = *lenp;
	int r = 0;
	int tindex = (unsigned long)table->extra1;
	struct net *net = current->nsproxy->net_ns;

	if (write) {
		if (size > sizeof(buf))
			size = sizeof(buf);
		if (copy_from_user(buf, buffer, size))
			return -EFAULT;

		if (!strcmp(buf, "NONE")) {
			nf_log_unbind_pf(net, tindex);
			return 0;
		}
		mutex_lock(&nf_log_mutex);
		logger = __find_logger(tindex, buf);
		if (logger == NULL) {
			mutex_unlock(&nf_log_mutex);
			return -ENOENT;
		}
		rcu_assign_pointer(net->nf.nf_loggers[tindex], logger);
		mutex_unlock(&nf_log_mutex);
	} else {
		mutex_lock(&nf_log_mutex);
		logger = nft_log_dereference(net->nf.nf_loggers[tindex]);
		if (!logger)
			table->data = "NONE";
		else
			table->data = logger->name;
		r = proc_dostring(table, write, buffer, lenp, ppos);
		mutex_unlock(&nf_log_mutex);
	}

	return r;
}

static int netfilter_log_sysctl_init(struct net *net)
{
	int i;
	struct ctl_table *table;

	table = nf_log_sysctl_table;
	if (!net_eq(net, &init_net)) {
		table = kmemdup(nf_log_sysctl_table,
				 sizeof(nf_log_sysctl_table),
				 GFP_KERNEL);
		if (!table)
			goto err_alloc;
	} else {
		for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
			snprintf(nf_log_sysctl_fnames[i],
				 3, "%d", i);
			nf_log_sysctl_table[i].procname	=
				nf_log_sysctl_fnames[i];
			nf_log_sysctl_table[i].data = NULL;
			nf_log_sysctl_table[i].maxlen = NFLOGGER_NAME_LEN;
			nf_log_sysctl_table[i].mode = 0644;
			nf_log_sysctl_table[i].proc_handler =
				nf_log_proc_dostring;
			nf_log_sysctl_table[i].extra1 =
				(void *)(unsigned long) i;
		}
	}

	net->nf.nf_log_dir_header = register_net_sysctl(net,
						"net/netfilter/nf_log",
						table);
	if (!net->nf.nf_log_dir_header)
		goto err_reg;

	return 0;

err_reg:
	if (!net_eq(net, &init_net))
		kfree(table);
err_alloc:
	return -ENOMEM;
}

static void netfilter_log_sysctl_exit(struct net *net)
{
	struct ctl_table *table;

	table = net->nf.nf_log_dir_header->ctl_table_arg;
	unregister_net_sysctl_table(net->nf.nf_log_dir_header);
	if (!net_eq(net, &init_net))
		kfree(table);
}
#else
static int netfilter_log_sysctl_init(struct net *net)
{
	return 0;
}

static void netfilter_log_sysctl_exit(struct net *net)
{
}
#endif /* CONFIG_SYSCTL */

static int __net_init nf_log_net_init(struct net *net)
{
	int ret = -ENOMEM;

#ifdef CONFIG_PROC_FS
	if (!proc_create("nf_log", S_IRUGO,
			 net->nf.proc_netfilter, &nflog_file_ops))
		return ret;
#endif
	ret = netfilter_log_sysctl_init(net);
	if (ret < 0)
		goto out_sysctl;

	return 0;

out_sysctl:
#ifdef CONFIG_PROC_FS
	remove_proc_entry("nf_log", net->nf.proc_netfilter);
#endif
	return ret;
}

static void __net_exit nf_log_net_exit(struct net *net)
{
	netfilter_log_sysctl_exit(net);
#ifdef CONFIG_PROC_FS
	remove_proc_entry("nf_log", net->nf.proc_netfilter);
#endif
}

static struct pernet_operations nf_log_net_ops = {
	.init = nf_log_net_init,
	.exit = nf_log_net_exit,
};

int __init netfilter_log_init(void)
{
	return register_pernet_subsys(&nf_log_net_ops);
}