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
19static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;
20static DEFINE_MUTEX(nf_log_mutex);
21
22#define nft_log_dereference(logger) \
23	rcu_dereference_protected(logger, lockdep_is_held(&nf_log_mutex))
24
25static 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
42void 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}
56EXPORT_SYMBOL(nf_log_set);
57
58void 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}
72EXPORT_SYMBOL(nf_log_unset);
73
74/* return EEXIST if the same logger is registered, 0 on success. */
75int 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
102unlock:
103	mutex_unlock(&nf_log_mutex);
104	return ret;
105}
106EXPORT_SYMBOL(nf_log_register);
107
108void 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}
122EXPORT_SYMBOL(nf_log_unregister);
123
124int 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}
138EXPORT_SYMBOL(nf_log_bind_pf);
139
140void 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}
148EXPORT_SYMBOL(nf_log_unbind_pf);
149
150void 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}
155EXPORT_SYMBOL_GPL(nf_logger_request_module);
156
157int 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;
172out:
173	rcu_read_unlock();
174	return ret;
175}
176EXPORT_SYMBOL_GPL(nf_logger_find_get);
177
178void 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}
189EXPORT_SYMBOL_GPL(nf_logger_put);
190
191void 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}
218EXPORT_SYMBOL(nf_log_packet);
219
220void 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}
242EXPORT_SYMBOL(nf_log_trace);
243
244#define S_SIZE (1024 - (sizeof(unsigned int) + 1))
245
246struct nf_log_buf {
247	unsigned int	count;
248	char		buf[S_SIZE + 1];
249};
250static 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}
270EXPORT_SYMBOL_GPL(nf_log_buf_add);
271
272struct 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}
285EXPORT_SYMBOL_GPL(nf_log_buf_open);
286
287void 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}
299EXPORT_SYMBOL_GPL(nf_log_buf_close);
300
301#ifdef CONFIG_PROC_FS
302static 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
314static 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
326static void seq_stop(struct seq_file *s, void *v)
327{
328	mutex_unlock(&nf_log_mutex);
329}
330
331static 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
368static 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
375static 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
381static 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
393static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
394static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
395
396static 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
438static 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
474err_reg:
475	if (!net_eq(net, &init_net))
476		kfree(table);
477err_alloc:
478	return -ENOMEM;
479}
480
481static 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
491static int netfilter_log_sysctl_init(struct net *net)
492{
493	return 0;
494}
495
496static void netfilter_log_sysctl_exit(struct net *net)
497{
498}
499#endif /* CONFIG_SYSCTL */
500
501static 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
516out_sysctl:
517#ifdef CONFIG_PROC_FS
518	remove_proc_entry("nf_log", net->nf.proc_netfilter);
519#endif
520	return ret;
521}
522
523static 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
531static struct pernet_operations nf_log_net_ops = {
532	.init = nf_log_net_init,
533	.exit = nf_log_net_exit,
534};
535
536int __init netfilter_log_init(void)
537{
538	return register_pernet_subsys(&nf_log_net_ops);
539}
540