aboutsummaryrefslogtreecommitdiff
path: root/net/netfilter/nf_log.c
blob: c93494fef8ef3cfdc8eb22352c59554d0c751eb2 (plain)
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
#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 const struct nf_logger *nf_loggers[NFPROTO_NUMPROTO] __read_mostly;
static struct list_head nf_loggers_l[NFPROTO_NUMPROTO] __read_mostly;
static DEFINE_MUTEX(nf_log_mutex);

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

	list_for_each_entry(t, &nf_loggers_l[pf], list[pf]) {
		if (!strnicmp(str_logger, t->name, strlen(t->name)))
			return t;
	}

	return NULL;
}

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

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

	for (i = 0; i < ARRAY_SIZE(logger->list); i++)
		INIT_LIST_HEAD(&logger->list[i]);

	mutex_lock(&nf_log_mutex);

	if (pf == NFPROTO_UNSPEC) {
		for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
			list_add_tail(&(logger->list[i]), &(nf_loggers_l[i]));
	} else {
		/* register at end of list to honor first register win */
		list_add_tail(&logger->list[pf], &nf_loggers_l[pf]);
		llog = rcu_dereference(nf_loggers[pf]);
		if (llog == NULL)
			rcu_assign_pointer(nf_loggers[pf], logger);
	}

	mutex_unlock(&nf_log_mutex);

	return 0;
}
EXPORT_SYMBOL(nf_log_register);

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

	mutex_lock(&nf_log_mutex);
	for (i = 0; i < ARRAY_SIZE(nf_loggers); i++) {
		c_logger = rcu_dereference(nf_loggers[i]);
		if (c_logger == logger)
			rcu_assign_pointer(nf_loggers[i], NULL);
		list_del(&logger->list[i]);
	}
	mutex_unlock(&nf_log_mutex);

	synchronize_rcu();
}
EXPORT_SYMBOL(nf_log_unregister);

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

void nf_log_unbind_pf(u_int8_t pf)
{
	mutex_lock(&nf_log_mutex);
	rcu_assign_pointer(nf_loggers[pf], NULL);
	mutex_unlock(&nf_log_mutex);
}
EXPORT_SYMBOL(nf_log_unbind_pf);

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

#ifdef CONFIG_PROC_FS
static void *seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(RCU)
{
	rcu_read_lock();

	if (*pos >= ARRAY_SIZE(nf_loggers))
		return NULL;

	return pos;
}

static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
{
	(*pos)++;

	if (*pos >= ARRAY_SIZE(nf_loggers))
		return NULL;

	return pos;
}

static void seq_stop(struct seq_file *s, void *v)
	__releases(RCU)
{
	rcu_read_unlock();
}

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

	logger = rcu_dereference(nf_loggers[*pos]);

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

	if (ret < 0)
		return ret;

	mutex_lock(&nf_log_mutex);
	list_for_each_entry(t, &nf_loggers_l[*pos], list[*pos]) {
		ret = seq_printf(s, "%s", t->name);
		if (ret < 0) {
			mutex_unlock(&nf_log_mutex);
			return ret;
		}
		if (&t->list[*pos] != nf_loggers_l[*pos].prev) {
			ret = seq_printf(s, ",");
			if (ret < 0) {
				mutex_unlock(&nf_log_mutex);
				return ret;
			}
		}
	}
	mutex_unlock(&nf_log_mutex);

	return seq_printf(s, ")\n");
}

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(file, &nflog_seq_ops);
}

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


#endif /* PROC_FS */

#ifdef CONFIG_SYSCTL
static struct ctl_path nf_log_sysctl_path[] = {
	{ .procname = "net", .ctl_name = CTL_NET, },
	{ .procname = "netfilter", .ctl_name = NET_NETFILTER, },
	{ .procname = "nf_log", .ctl_name = CTL_UNNUMBERED, },
	{ }
};

static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
static struct ctl_table_header *nf_log_dir_header;

static int nf_log_proc_dostring(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;

	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(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(nf_loggers[tindex], logger);
		mutex_unlock(&nf_log_mutex);
	} else {
		mutex_lock(&nf_log_mutex);
		logger = 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 __init int netfilter_log_sysctl_init(void)
{
	int i;

	for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
		snprintf(nf_log_sysctl_fnames[i-NFPROTO_UNSPEC], 3, "%d", i);
		nf_log_sysctl_table[i].ctl_name	= CTL_UNNUMBERED;
		nf_log_sysctl_table[i].procname	=
			nf_log_sysctl_fnames[i-NFPROTO_UNSPEC];
		nf_log_sysctl_table[i].data = NULL;
		nf_log_sysctl_table[i].maxlen =
			NFLOGGER_NAME_LEN * sizeof(char);
		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;
	}

	nf_log_dir_header = register_sysctl_paths(nf_log_sysctl_path,
				       nf_log_sysctl_table);
	if (!nf_log_dir_header)
		return -ENOMEM;

	return 0;
}
#else
static __init int netfilter_log_sysctl_init(void)
{
	return 0;
}
#endif /* CONFIG_SYSCTL */

int __init netfilter_log_init(void)
{
	int i, r;
#ifdef CONFIG_PROC_FS
	if (!proc_create("nf_log", S_IRUGO,
			 proc_net_netfilter, &nflog_file_ops))
		return -1;
#endif

	/* Errors will trigger panic, unroll on error is unnecessary. */
	r = netfilter_log_sysctl_init();
	if (r < 0)
		return r;

	for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
		INIT_LIST_HEAD(&(nf_loggers_l[i]));

	return 0;
}