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 const struct nf_logger __rcu *nf_loggers[NFPROTO_NUMPROTO] __read_mostly;
20 static struct list_head nf_loggers_l[NFPROTO_NUMPROTO] __read_mostly;
21 static DEFINE_MUTEX(nf_log_mutex);
22
__find_logger(int pf,const char * str_logger)23 static struct nf_logger *__find_logger(int pf, const char *str_logger)
24 {
25 struct nf_logger *t;
26
27 list_for_each_entry(t, &nf_loggers_l[pf], list[pf]) {
28 if (!strnicmp(str_logger, t->name, strlen(t->name)))
29 return t;
30 }
31
32 return NULL;
33 }
34
35 /* return EEXIST if the same logger is registred, 0 on success. */
nf_log_register(u_int8_t pf,struct nf_logger * logger)36 int nf_log_register(u_int8_t pf, struct nf_logger *logger)
37 {
38 const struct nf_logger *llog;
39 int i;
40
41 if (pf >= ARRAY_SIZE(nf_loggers))
42 return -EINVAL;
43
44 for (i = 0; i < ARRAY_SIZE(logger->list); i++)
45 INIT_LIST_HEAD(&logger->list[i]);
46
47 mutex_lock(&nf_log_mutex);
48
49 if (pf == NFPROTO_UNSPEC) {
50 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
51 list_add_tail(&(logger->list[i]), &(nf_loggers_l[i]));
52 } else {
53 /* register at end of list to honor first register win */
54 list_add_tail(&logger->list[pf], &nf_loggers_l[pf]);
55 llog = rcu_dereference_protected(nf_loggers[pf],
56 lockdep_is_held(&nf_log_mutex));
57 if (llog == NULL)
58 rcu_assign_pointer(nf_loggers[pf], logger);
59 }
60
61 mutex_unlock(&nf_log_mutex);
62
63 return 0;
64 }
65 EXPORT_SYMBOL(nf_log_register);
66
nf_log_unregister(struct nf_logger * logger)67 void nf_log_unregister(struct nf_logger *logger)
68 {
69 const struct nf_logger *c_logger;
70 int i;
71
72 mutex_lock(&nf_log_mutex);
73 for (i = 0; i < ARRAY_SIZE(nf_loggers); i++) {
74 c_logger = rcu_dereference_protected(nf_loggers[i],
75 lockdep_is_held(&nf_log_mutex));
76 if (c_logger == logger)
77 RCU_INIT_POINTER(nf_loggers[i], NULL);
78 list_del(&logger->list[i]);
79 }
80 mutex_unlock(&nf_log_mutex);
81
82 synchronize_rcu();
83 }
84 EXPORT_SYMBOL(nf_log_unregister);
85
nf_log_bind_pf(u_int8_t pf,const struct nf_logger * logger)86 int nf_log_bind_pf(u_int8_t pf, const struct nf_logger *logger)
87 {
88 if (pf >= ARRAY_SIZE(nf_loggers))
89 return -EINVAL;
90 mutex_lock(&nf_log_mutex);
91 if (__find_logger(pf, logger->name) == NULL) {
92 mutex_unlock(&nf_log_mutex);
93 return -ENOENT;
94 }
95 rcu_assign_pointer(nf_loggers[pf], logger);
96 mutex_unlock(&nf_log_mutex);
97 return 0;
98 }
99 EXPORT_SYMBOL(nf_log_bind_pf);
100
nf_log_unbind_pf(u_int8_t pf)101 void nf_log_unbind_pf(u_int8_t pf)
102 {
103 if (pf >= ARRAY_SIZE(nf_loggers))
104 return;
105 mutex_lock(&nf_log_mutex);
106 RCU_INIT_POINTER(nf_loggers[pf], NULL);
107 mutex_unlock(&nf_log_mutex);
108 }
109 EXPORT_SYMBOL(nf_log_unbind_pf);
110
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,...)111 void nf_log_packet(u_int8_t pf,
112 unsigned int hooknum,
113 const struct sk_buff *skb,
114 const struct net_device *in,
115 const struct net_device *out,
116 const struct nf_loginfo *loginfo,
117 const char *fmt, ...)
118 {
119 va_list args;
120 char prefix[NF_LOG_PREFIXLEN];
121 const struct nf_logger *logger;
122
123 rcu_read_lock();
124 logger = rcu_dereference(nf_loggers[pf]);
125 if (logger) {
126 va_start(args, fmt);
127 vsnprintf(prefix, sizeof(prefix), fmt, args);
128 va_end(args);
129 logger->logfn(pf, hooknum, skb, in, out, loginfo, prefix);
130 }
131 rcu_read_unlock();
132 }
133 EXPORT_SYMBOL(nf_log_packet);
134
135 #ifdef CONFIG_PROC_FS
seq_start(struct seq_file * seq,loff_t * pos)136 static void *seq_start(struct seq_file *seq, loff_t *pos)
137 {
138 mutex_lock(&nf_log_mutex);
139
140 if (*pos >= ARRAY_SIZE(nf_loggers))
141 return NULL;
142
143 return pos;
144 }
145
seq_next(struct seq_file * s,void * v,loff_t * pos)146 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
147 {
148 (*pos)++;
149
150 if (*pos >= ARRAY_SIZE(nf_loggers))
151 return NULL;
152
153 return pos;
154 }
155
seq_stop(struct seq_file * s,void * v)156 static void seq_stop(struct seq_file *s, void *v)
157 {
158 mutex_unlock(&nf_log_mutex);
159 }
160
seq_show(struct seq_file * s,void * v)161 static int seq_show(struct seq_file *s, void *v)
162 {
163 loff_t *pos = v;
164 const struct nf_logger *logger;
165 struct nf_logger *t;
166 int ret;
167
168 logger = rcu_dereference_protected(nf_loggers[*pos],
169 lockdep_is_held(&nf_log_mutex));
170
171 if (!logger)
172 ret = seq_printf(s, "%2lld NONE (", *pos);
173 else
174 ret = seq_printf(s, "%2lld %s (", *pos, logger->name);
175
176 if (ret < 0)
177 return ret;
178
179 list_for_each_entry(t, &nf_loggers_l[*pos], list[*pos]) {
180 ret = seq_printf(s, "%s", t->name);
181 if (ret < 0)
182 return ret;
183 if (&t->list[*pos] != nf_loggers_l[*pos].prev) {
184 ret = seq_printf(s, ",");
185 if (ret < 0)
186 return ret;
187 }
188 }
189
190 return seq_printf(s, ")\n");
191 }
192
193 static const struct seq_operations nflog_seq_ops = {
194 .start = seq_start,
195 .next = seq_next,
196 .stop = seq_stop,
197 .show = seq_show,
198 };
199
nflog_open(struct inode * inode,struct file * file)200 static int nflog_open(struct inode *inode, struct file *file)
201 {
202 return seq_open(file, &nflog_seq_ops);
203 }
204
205 static const struct file_operations nflog_file_ops = {
206 .owner = THIS_MODULE,
207 .open = nflog_open,
208 .read = seq_read,
209 .llseek = seq_lseek,
210 .release = seq_release,
211 };
212
213
214 #endif /* PROC_FS */
215
216 #ifdef CONFIG_SYSCTL
217 static struct ctl_path nf_log_sysctl_path[] = {
218 { .procname = "net", },
219 { .procname = "netfilter", },
220 { .procname = "nf_log", },
221 { }
222 };
223
224 static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
225 static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
226 static struct ctl_table_header *nf_log_dir_header;
227
nf_log_proc_dostring(ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)228 static int nf_log_proc_dostring(ctl_table *table, int write,
229 void __user *buffer, size_t *lenp, loff_t *ppos)
230 {
231 const struct nf_logger *logger;
232 char buf[NFLOGGER_NAME_LEN];
233 size_t size = *lenp;
234 int r = 0;
235 int tindex = (unsigned long)table->extra1;
236
237 if (write) {
238 if (size > sizeof(buf))
239 size = sizeof(buf);
240 if (copy_from_user(buf, buffer, size))
241 return -EFAULT;
242
243 if (!strcmp(buf, "NONE")) {
244 nf_log_unbind_pf(tindex);
245 return 0;
246 }
247 mutex_lock(&nf_log_mutex);
248 logger = __find_logger(tindex, buf);
249 if (logger == NULL) {
250 mutex_unlock(&nf_log_mutex);
251 return -ENOENT;
252 }
253 rcu_assign_pointer(nf_loggers[tindex], logger);
254 mutex_unlock(&nf_log_mutex);
255 } else {
256 mutex_lock(&nf_log_mutex);
257 logger = rcu_dereference_protected(nf_loggers[tindex],
258 lockdep_is_held(&nf_log_mutex));
259 if (!logger)
260 table->data = "NONE";
261 else
262 table->data = logger->name;
263 r = proc_dostring(table, write, buffer, lenp, ppos);
264 mutex_unlock(&nf_log_mutex);
265 }
266
267 return r;
268 }
269
netfilter_log_sysctl_init(void)270 static __init int netfilter_log_sysctl_init(void)
271 {
272 int i;
273
274 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
275 snprintf(nf_log_sysctl_fnames[i-NFPROTO_UNSPEC], 3, "%d", i);
276 nf_log_sysctl_table[i].procname =
277 nf_log_sysctl_fnames[i-NFPROTO_UNSPEC];
278 nf_log_sysctl_table[i].data = NULL;
279 nf_log_sysctl_table[i].maxlen =
280 NFLOGGER_NAME_LEN * sizeof(char);
281 nf_log_sysctl_table[i].mode = 0644;
282 nf_log_sysctl_table[i].proc_handler = nf_log_proc_dostring;
283 nf_log_sysctl_table[i].extra1 = (void *)(unsigned long) i;
284 }
285
286 nf_log_dir_header = register_sysctl_paths(nf_log_sysctl_path,
287 nf_log_sysctl_table);
288 if (!nf_log_dir_header)
289 return -ENOMEM;
290
291 return 0;
292 }
293 #else
netfilter_log_sysctl_init(void)294 static __init int netfilter_log_sysctl_init(void)
295 {
296 return 0;
297 }
298 #endif /* CONFIG_SYSCTL */
299
netfilter_log_init(void)300 int __init netfilter_log_init(void)
301 {
302 int i, r;
303 #ifdef CONFIG_PROC_FS
304 if (!proc_create("nf_log", S_IRUGO,
305 proc_net_netfilter, &nflog_file_ops))
306 return -1;
307 #endif
308
309 /* Errors will trigger panic, unroll on error is unnecessary. */
310 r = netfilter_log_sysctl_init();
311 if (r < 0)
312 return r;
313
314 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
315 INIT_LIST_HEAD(&(nf_loggers_l[i]));
316
317 return 0;
318 }
319