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 struct list_head nf_loggers_l[NFPROTO_NUMPROTO] __read_mostly;
  20 static DEFINE_MUTEX(nf_log_mutex);
  21
  22 static struct nf_logger *__find_logger(int pf, const char *str_logger)
  23 {
  24         struct nf_logger *t;
  25
  26         list_for_each_entry(t, &nf_loggers_l[pf], list[pf]) {
  27                 if (!strnicmp(str_logger, t->name, strlen(t->name)))
  28                         return t;
  29         }
  30
  31         return NULL;
  32 }
  33
  34 void nf_log_set(struct net *net, u_int8_t pf, const struct nf_logger *logger)
  35 {
  36         const struct nf_logger *log;
  37
  38         if (pf == NFPROTO_UNSPEC)
  39                 return;
  40
  41         mutex_lock(&nf_log_mutex);
  42         log = rcu_dereference_protected(net->nf.nf_loggers[pf],
  43                                         lockdep_is_held(&nf_log_mutex));
  44         if (log == NULL)
  45                 rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
  46
  47         mutex_unlock(&nf_log_mutex);
  48 }
  49 EXPORT_SYMBOL(nf_log_set);
  50
  51 void nf_log_unset(struct net *net, const struct nf_logger *logger)
  52 {
  53         int i;
  54         const struct nf_logger *log;
  55
  56         mutex_lock(&nf_log_mutex);
  57         for (i = 0; i < NFPROTO_NUMPROTO; i++) {
  58                 log = rcu_dereference_protected(net->nf.nf_loggers[i],
  59                                 lockdep_is_held(&nf_log_mutex));
  60                 if (log == logger)
  61                         RCU_INIT_POINTER(net->nf.nf_loggers[i], NULL);
  62         }
  63         mutex_unlock(&nf_log_mutex);
  64         synchronize_rcu();
  65 }
  66 EXPORT_SYMBOL(nf_log_unset);
  67
  68 /* return EEXIST if the same logger is registered, 0 on success. */
  69 int nf_log_register(u_int8_t pf, struct nf_logger *logger)
  70 {
  71         int i;
  72
  73         if (pf >= ARRAY_SIZE(init_net.nf.nf_loggers))
  74                 return -EINVAL;
  75
  76         for (i = 0; i < ARRAY_SIZE(logger->list); i++)
  77                 INIT_LIST_HEAD(&logger->list[i]);
  78
  79         mutex_lock(&nf_log_mutex);
  80
  81         if (pf == NFPROTO_UNSPEC) {
  82                 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
  83                         list_add_tail(&(logger->list[i]), &(nf_loggers_l[i]));
  84         } else {
  85                 /* register at end of list to honor first register win */
  86                 list_add_tail(&logger->list[pf], &nf_loggers_l[pf]);
  87         }
  88
  89         mutex_unlock(&nf_log_mutex);
  90
  91         return 0;
  92 }
  93 EXPORT_SYMBOL(nf_log_register);
  94
  95 void nf_log_unregister(struct nf_logger *logger)
  96 {
  97         int i;
  98
  99         mutex_lock(&nf_log_mutex);
 100         for (i = 0; i < NFPROTO_NUMPROTO; i++)
 101                 list_del(&logger->list[i]);
 102         mutex_unlock(&nf_log_mutex);
 103 }
 104 EXPORT_SYMBOL(nf_log_unregister);
 105
 106 int nf_log_bind_pf(struct net *net, u_int8_t pf,
 107                    const struct nf_logger *logger)
 108 {
 109         if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
 110                 return -EINVAL;
 111         mutex_lock(&nf_log_mutex);
 112         if (__find_logger(pf, logger->name) == NULL) {
 113                 mutex_unlock(&nf_log_mutex);
 114                 return -ENOENT;
 115         }
 116         rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
 117         mutex_unlock(&nf_log_mutex);
 118         return 0;
 119 }
 120 EXPORT_SYMBOL(nf_log_bind_pf);
 121
 122 void nf_log_unbind_pf(struct net *net, u_int8_t pf)
 123 {
 124         if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
 125                 return;
 126         mutex_lock(&nf_log_mutex);
 127         RCU_INIT_POINTER(net->nf.nf_loggers[pf], NULL);
 128         mutex_unlock(&nf_log_mutex);
 129 }
 130 EXPORT_SYMBOL(nf_log_unbind_pf);
 131
 132 void nf_log_packet(struct net *net,
 133                    u_int8_t pf,
 134                    unsigned int hooknum,
 135                    const struct sk_buff *skb,
 136                    const struct net_device *in,
 137                    const struct net_device *out,
 138                    const struct nf_loginfo *loginfo,
 139                    const char *fmt, ...)
 140 {
 141         va_list args;
 142         char prefix[NF_LOG_PREFIXLEN];
 143         const struct nf_logger *logger;
 144
 145         rcu_read_lock();
 146         logger = rcu_dereference(net->nf.nf_loggers[pf]);
 147         if (logger) {
 148                 va_start(args, fmt);
 149                 vsnprintf(prefix, sizeof(prefix), fmt, args);
 150                 va_end(args);
 151                 logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
 152         }
 153         rcu_read_unlock();
 154 }
 155 EXPORT_SYMBOL(nf_log_packet);
 156
 157 #ifdef CONFIG_PROC_FS
 158 static void *seq_start(struct seq_file *seq, loff_t *pos)
 159 {
 160         struct net *net = seq_file_net(seq);
 161
 162         mutex_lock(&nf_log_mutex);
 163
 164         if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
 165                 return NULL;
 166
 167         return pos;
 168 }
 169
 170 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 171 {
 172         struct net *net = seq_file_net(s);
 173
 174         (*pos)++;
 175
 176         if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
 177                 return NULL;
 178
 179         return pos;
 180 }
 181
 182 static void seq_stop(struct seq_file *s, void *v)
 183 {
 184         mutex_unlock(&nf_log_mutex);
 185 }
 186
 187 static int seq_show(struct seq_file *s, void *v)
 188 {
 189         loff_t *pos = v;
 190         const struct nf_logger *logger;
 191         struct nf_logger *t;
 192         int ret;
 193         struct net *net = seq_file_net(s);
 194
 195         logger = rcu_dereference_protected(net->nf.nf_loggers[*pos],
 196                                            lockdep_is_held(&nf_log_mutex));
 197
 198         if (!logger)
 199                 ret = seq_printf(s, "%2lld NONE (", *pos);
 200         else
 201                 ret = seq_printf(s, "%2lld %s (", *pos, logger->name);
 202
 203         if (ret < 0)
 204                 return ret;
 205
 206         list_for_each_entry(t, &nf_loggers_l[*pos], list[*pos]) {
 207                 ret = seq_printf(s, "%s", t->name);
 208                 if (ret < 0)
 209                         return ret;
 210                 if (&t->list[*pos] != nf_loggers_l[*pos].prev) {
 211                         ret = seq_printf(s, ",");
 212                         if (ret < 0)
 213                                 return ret;
 214                 }
 215         }
 216
 217         return seq_printf(s, ")\n");
 218 }
 219
 220 static const struct seq_operations nflog_seq_ops = {
 221         .start  = seq_start,
 222         .next   = seq_next,
 223         .stop   = seq_stop,
 224         .show   = seq_show,
 225 };
 226
 227 static int nflog_open(struct inode *inode, struct file *file)
 228 {
 229         return seq_open_net(inode, file, &nflog_seq_ops,
 230                             sizeof(struct seq_net_private));
 231 }
 232
 233 static const struct file_operations nflog_file_ops = {
 234         .owner   = THIS_MODULE,
 235         .open    = nflog_open,
 236         .read    = seq_read,
 237         .llseek  = seq_lseek,
 238         .release = seq_release_net,
 239 };
 240
 241
 242 #endif /* PROC_FS */
 243
 244 #ifdef CONFIG_SYSCTL
 245 static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
 246 static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
 247
 248 static int nf_log_proc_dostring(ctl_table *table, int write,
 249                          void __user *buffer, size_t *lenp, loff_t *ppos)
 250 {
 251         const struct nf_logger *logger;
 252         char buf[NFLOGGER_NAME_LEN];
 253         size_t size = *lenp;
 254         int r = 0;
 255         int tindex = (unsigned long)table->extra1;
 256         struct net *net = current->nsproxy->net_ns;
 257
 258         if (write) {
 259                 if (size > sizeof(buf))
 260                         size = sizeof(buf);
 261                 if (copy_from_user(buf, buffer, size))
 262                         return -EFAULT;
 263
 264                 if (!strcmp(buf, "NONE")) {
 265                         nf_log_unbind_pf(net, tindex);
 266                         return 0;
 267                 }
 268                 mutex_lock(&nf_log_mutex);
 269                 logger = __find_logger(tindex, buf);
 270                 if (logger == NULL) {
 271                         mutex_unlock(&nf_log_mutex);
 272                         return -ENOENT;
 273                 }
 274                 rcu_assign_pointer(net->nf.nf_loggers[tindex], logger);
 275                 mutex_unlock(&nf_log_mutex);
 276         } else {
 277                 mutex_lock(&nf_log_mutex);
 278                 logger = rcu_dereference_protected(net->nf.nf_loggers[tindex],
 279                                                    lockdep_is_held(&nf_log_mutex));
 280                 if (!logger)
 281                         table->data = "NONE";
 282                 else
 283                         table->data = logger->name;
 284                 r = proc_dostring(table, write, buffer, lenp, ppos);
 285                 mutex_unlock(&nf_log_mutex);
 286         }
 287
 288         return r;
 289 }
 290
 291 static int netfilter_log_sysctl_init(struct net *net)
 292 {
 293         int i;
 294         struct ctl_table *table;
 295
 296         table = nf_log_sysctl_table;
 297         if (!net_eq(net, &init_net)) {
 298                 table = kmemdup(nf_log_sysctl_table,
 299                                  sizeof(nf_log_sysctl_table),
 300                                  GFP_KERNEL);
 301                 if (!table)
 302                         goto err_alloc;
 303         } else {
 304                 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
 305                         snprintf(nf_log_sysctl_fnames[i],
 306                                  3, "%d", i);
 307                         nf_log_sysctl_table[i].procname =
 308                                 nf_log_sysctl_fnames[i];
 309                         nf_log_sysctl_table[i].data = NULL;
 310                         nf_log_sysctl_table[i].maxlen =
 311                                 NFLOGGER_NAME_LEN * sizeof(char);
 312                         nf_log_sysctl_table[i].mode = 0644;
 313                         nf_log_sysctl_table[i].proc_handler =
 314                                 nf_log_proc_dostring;
 315                         nf_log_sysctl_table[i].extra1 =
 316                                 (void *)(unsigned long) i;
 317                 }
 318         }
 319
 320         net->nf.nf_log_dir_header = register_net_sysctl(net,
 321                                                 "net/netfilter/nf_log",
 322                                                 table);
 323         if (!net->nf.nf_log_dir_header)
 324                 goto err_reg;
 325
 326         return 0;
 327
 328 err_reg:
 329         if (!net_eq(net, &init_net))
 330                 kfree(table);
 331 err_alloc:
 332         return -ENOMEM;
 333 }
 334
 335 static void netfilter_log_sysctl_exit(struct net *net)
 336 {
 337         struct ctl_table *table;
 338
 339         table = net->nf.nf_log_dir_header->ctl_table_arg;
 340         unregister_net_sysctl_table(net->nf.nf_log_dir_header);
 341         if (!net_eq(net, &init_net))
 342                 kfree(table);
 343 }
 344 #else
 345 static int netfilter_log_sysctl_init(struct net *net)
 346 {
 347         return 0;
 348 }
 349
 350 static void netfilter_log_sysctl_exit(struct net *net)
 351 {
 352 }
 353 #endif /* CONFIG_SYSCTL */
 354
 355 static int __net_init nf_log_net_init(struct net *net)
 356 {
 357         int ret = -ENOMEM;
 358
 359 #ifdef CONFIG_PROC_FS
 360         if (!proc_create("nf_log", S_IRUGO,
 361                          net->nf.proc_netfilter, &nflog_file_ops))
 362                 return ret;
 363 #endif
 364         ret = netfilter_log_sysctl_init(net);
 365         if (ret < 0)
 366                 goto out_sysctl;
 367
 368         return 0;
 369
 370 out_sysctl:
 371 #ifdef CONFIG_PROC_FS
 372         /* For init_net: errors will trigger panic, don't unroll on error. */
 373         if (!net_eq(net, &init_net))
 374                 remove_proc_entry("nf_log", net->nf.proc_netfilter);
 375 #endif
 376         return ret;
 377 }
 378
 379 static void __net_exit nf_log_net_exit(struct net *net)
 380 {
 381         netfilter_log_sysctl_exit(net);
 382 #ifdef CONFIG_PROC_FS
 383         remove_proc_entry("nf_log", net->nf.proc_netfilter);
 384 #endif
 385 }
 386
 387 static struct pernet_operations nf_log_net_ops = {
 388         .init = nf_log_net_init,
 389         .exit = nf_log_net_exit,
 390 };
 391
 392 int __init netfilter_log_init(void)
 393 {
 394         int i, ret;
 395
 396         ret = register_pernet_subsys(&nf_log_net_ops);
 397         if (ret < 0)
 398                 return ret;
 399
 400         for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
 401                 INIT_LIST_HEAD(&(nf_loggers_l[i]));
 402
 403         return 0;
 404 }