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         if (pf >= ARRAY_SIZE(nf_loggers))
  87                 return -EINVAL;
  88         mutex_lock(&nf_log_mutex);
  89         if (__find_logger(pf, logger->name) == NULL) {
  90                 mutex_unlock(&nf_log_mutex);
  91                 return -ENOENT;
  92         }
  93         rcu_assign_pointer(nf_loggers[pf], logger);
  94         mutex_unlock(&nf_log_mutex);
  95         return 0;
  96 }
  97 EXPORT_SYMBOL(nf_log_bind_pf);
  98
  99 void nf_log_unbind_pf(u_int8_t pf)
 100 {
 101         if (pf >= ARRAY_SIZE(nf_loggers))
 102                 return;
 103         mutex_lock(&nf_log_mutex);
 104         rcu_assign_pointer(nf_loggers[pf], NULL);
 105         mutex_unlock(&nf_log_mutex);
 106 }
 107 EXPORT_SYMBOL(nf_log_unbind_pf);
 108
 109 void nf_log_packet(u_int8_t pf,
 110                    unsigned int hooknum,
 111                    const struct sk_buff *skb,
 112                    const struct net_device *in,
 113                    const struct net_device *out,
 114                    const struct nf_loginfo *loginfo,
 115                    const char *fmt, ...)
 116 {
 117         va_list args;
 118         char prefix[NF_LOG_PREFIXLEN];
 119         const struct nf_logger *logger;
 120
 121         rcu_read_lock();
 122         logger = rcu_dereference(nf_loggers[pf]);
 123         if (logger) {
 124                 va_start(args, fmt);
 125                 vsnprintf(prefix, sizeof(prefix), fmt, args);
 126                 va_end(args);
 127                 logger->logfn(pf, hooknum, skb, in, out, loginfo, prefix);
 128         }
 129         rcu_read_unlock();
 130 }
 131 EXPORT_SYMBOL(nf_log_packet);
 132
 133 #ifdef CONFIG_PROC_FS
 134 static void *seq_start(struct seq_file *seq, loff_t *pos)
 135 {
 136         mutex_lock(&nf_log_mutex);
 137
 138         if (*pos >= ARRAY_SIZE(nf_loggers))
 139                 return NULL;
 140
 141         return pos;
 142 }
 143
 144 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 145 {
 146         (*pos)++;
 147
 148         if (*pos >= ARRAY_SIZE(nf_loggers))
 149                 return NULL;
 150
 151         return pos;
 152 }
 153
 154 static void seq_stop(struct seq_file *s, void *v)
 155 {
 156         mutex_unlock(&nf_log_mutex);
 157 }
 158
 159 static int seq_show(struct seq_file *s, void *v)
 160 {
 161         loff_t *pos = v;
 162         const struct nf_logger *logger;
 163         struct nf_logger *t;
 164         int ret;
 165
 166         logger = nf_loggers[*pos];
 167
 168         if (!logger)
 169                 ret = seq_printf(s, "%2lld NONE (", *pos);
 170         else
 171                 ret = seq_printf(s, "%2lld %s (", *pos, logger->name);
 172
 173         if (ret < 0)
 174                 return ret;
 175
 176         list_for_each_entry(t, &nf_loggers_l[*pos], list[*pos]) {
 177                 ret = seq_printf(s, "%s", t->name);
 178                 if (ret < 0)
 179                         return ret;
 180                 if (&t->list[*pos] != nf_loggers_l[*pos].prev) {
 181                         ret = seq_printf(s, ",");
 182                         if (ret < 0)
 183                                 return ret;
 184                 }
 185         }
 186
 187         return seq_printf(s, ")\n");
 188 }
 189
 190 static const struct seq_operations nflog_seq_ops = {
 191         .start  = seq_start,
 192         .next   = seq_next,
 193         .stop   = seq_stop,
 194         .show   = seq_show,
 195 };
 196
 197 static int nflog_open(struct inode *inode, struct file *file)
 198 {
 199         return seq_open(file, &nflog_seq_ops);
 200 }
 201
 202 static const struct file_operations nflog_file_ops = {
 203         .owner   = THIS_MODULE,
 204         .open    = nflog_open,
 205         .read    = seq_read,
 206         .llseek  = seq_lseek,
 207         .release = seq_release,
 208 };
 209
 210
 211 #endif /* PROC_FS */
 212
 213 #ifdef CONFIG_SYSCTL
 214 static struct ctl_path nf_log_sysctl_path[] = {
 215         { .procname = "net", .ctl_name = CTL_NET, },
 216         { .procname = "netfilter", .ctl_name = NET_NETFILTER, },
 217         { .procname = "nf_log", .ctl_name = CTL_UNNUMBERED, },
 218         { }
 219 };
 220
 221 static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
 222 static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
 223 static struct ctl_table_header *nf_log_dir_header;
 224
 225 static int nf_log_proc_dostring(ctl_table *table, int write,
 226                          void __user *buffer, size_t *lenp, loff_t *ppos)
 227 {
 228         const struct nf_logger *logger;
 229         char buf[NFLOGGER_NAME_LEN];
 230         size_t size = *lenp;
 231         int r = 0;
 232         int tindex = (unsigned long)table->extra1;
 233
 234         if (write) {
 235                 if (size > sizeof(buf))
 236                         size = sizeof(buf);
 237                 if (copy_from_user(buf, buffer, size))
 238                         return -EFAULT;
 239
 240                 if (!strcmp(buf, "NONE")) {
 241                         nf_log_unbind_pf(tindex);
 242                         return 0;
 243                 }
 244                 mutex_lock(&nf_log_mutex);
 245                 logger = __find_logger(tindex, buf);
 246                 if (logger == NULL) {
 247                         mutex_unlock(&nf_log_mutex);
 248                         return -ENOENT;
 249                 }
 250                 rcu_assign_pointer(nf_loggers[tindex], logger);
 251                 mutex_unlock(&nf_log_mutex);
 252         } else {
 253                 mutex_lock(&nf_log_mutex);
 254                 logger = nf_loggers[tindex];
 255                 if (!logger)
 256                         table->data = "NONE";
 257                 else
 258                         table->data = logger->name;
 259                 r = proc_dostring(table, write, buffer, lenp, ppos);
 260                 mutex_unlock(&nf_log_mutex);
 261         }
 262
 263         return r;
 264 }
 265
 266 static __init int netfilter_log_sysctl_init(void)
 267 {
 268         int i;
 269
 270         for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
 271                 snprintf(nf_log_sysctl_fnames[i-NFPROTO_UNSPEC], 3, "%d", i);
 272                 nf_log_sysctl_table[i].ctl_name = CTL_UNNUMBERED;
 273                 nf_log_sysctl_table[i].procname =
 274                         nf_log_sysctl_fnames[i-NFPROTO_UNSPEC];
 275                 nf_log_sysctl_table[i].data = NULL;
 276                 nf_log_sysctl_table[i].maxlen =
 277                         NFLOGGER_NAME_LEN * sizeof(char);
 278                 nf_log_sysctl_table[i].mode = 0644;
 279                 nf_log_sysctl_table[i].proc_handler = nf_log_proc_dostring;
 280                 nf_log_sysctl_table[i].extra1 = (void *)(unsigned long) i;
 281         }
 282
 283         nf_log_dir_header = register_sysctl_paths(nf_log_sysctl_path,
 284                                        nf_log_sysctl_table);
 285         if (!nf_log_dir_header)
 286                 return -ENOMEM;
 287
 288         return 0;
 289 }
 290 #else
 291 static __init int netfilter_log_sysctl_init(void)
 292 {
 293         return 0;
 294 }
 295 #endif /* CONFIG_SYSCTL */
 296
 297 int __init netfilter_log_init(void)
 298 {
 299         int i, r;
 300 #ifdef CONFIG_PROC_FS
 301         if (!proc_create("nf_log", S_IRUGO,
 302                          proc_net_netfilter, &nflog_file_ops))
 303                 return -1;
 304 #endif
 305
 306         /* Errors will trigger panic, unroll on error is unnecessary. */
 307         r = netfilter_log_sysctl_init();
 308         if (r < 0)
 309                 return r;
 310
 311         for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
 312                 INIT_LIST_HEAD(&(nf_loggers_l[i]));
 313
 314         return 0;
 315 }