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