net/netfilter/nf_log.c

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