extensions/libip6t_LOG.c

   1 /* Shared library add-on to iptables to add LOG support. */
   2 #include <stdio.h>
   3 #include <netdb.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <syslog.h>
   7 #include <getopt.h>
   8 #include <ip6tables.h>
   9 #include <linux/netfilter_ipv6/ip6_tables.h>
  10 #include <linux/netfilter_ipv6/ip6t_LOG.h>
  11
  12 #ifndef IP6T_LOG_UID    /* Old kernel */
  13 #define IP6T_LOG_UID    0x08
  14 #undef  IP6T_LOG_MASK
  15 #define IP6T_LOG_MASK   0x0f
  16 #endif
  17
  18 #define LOG_DEFAULT_LEVEL LOG_WARNING
  19
  20 /* Function which prints out usage message. */
  21 static void LOG_help(void)
  22 {
  23         printf(
  24 "LOG target options:\n"
  25 " --log-level level             Level of logging (numeric or see syslog.conf)\n"
  26 " --log-prefix prefix           Prefix log messages with this prefix.\n"
  27 " --log-tcp-sequence            Log TCP sequence numbers.\n"
  28 " --log-tcp-options             Log TCP options.\n"
  29 " --log-ip-options              Log IP options.\n"
  30 " --log-uid                     Log UID owning the local socket.\n");
  31 }
  32
  33 static const struct option LOG_opts[] = {
  34         { .name = "log-level",        .has_arg = 1, .val = '!' },
  35         { .name = "log-prefix",       .has_arg = 1, .val = '#' },
  36         { .name = "log-tcp-sequence", .has_arg = 0, .val = '1' },
  37         { .name = "log-tcp-options",  .has_arg = 0, .val = '2' },
  38         { .name = "log-ip-options",   .has_arg = 0, .val = '3' },
  39         { .name = "log-uid",          .has_arg = 0, .val = '4' },
  40         { .name = NULL }
  41 };
  42
  43 /* Initialize the target. */
  44 static void LOG_init(struct xt_entry_target *t)
  45 {
  46         struct ip6t_log_info *loginfo = (struct ip6t_log_info *)t->data;
  47
  48         loginfo->level = LOG_DEFAULT_LEVEL;
  49
  50 }
  51
  52 struct ip6t_log_names {
  53         const char *name;
  54         unsigned int level;
  55 };
  56
  57 static const struct ip6t_log_names ip6t_log_names[]
  58 = { { .name = "alert",   .level = LOG_ALERT },
  59     { .name = "crit",    .level = LOG_CRIT },
  60     { .name = "debug",   .level = LOG_DEBUG },
  61     { .name = "emerg",   .level = LOG_EMERG },
  62     { .name = "error",   .level = LOG_ERR },            /* DEPRECATED */
  63     { .name = "info",    .level = LOG_INFO },
  64     { .name = "notice",  .level = LOG_NOTICE },
  65     { .name = "panic",   .level = LOG_EMERG },          /* DEPRECATED */
  66     { .name = "warning", .level = LOG_WARNING }
  67 };
  68
  69 static u_int8_t
  70 parse_level(const char *level)
  71 {
  72         unsigned int lev = -1;
  73         unsigned int set = 0;
  74
  75         if (string_to_number(level, 0, 7, &lev) == -1) {
  76                 unsigned int i = 0;
  77
  78                 for (i = 0;
  79                      i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
  80                      i++) {
  81                         if (strncasecmp(level, ip6t_log_names[i].name,
  82                                         strlen(level)) == 0) {
  83                                 if (set++)
  84                                         exit_error(PARAMETER_PROBLEM,
  85                                                    "log-level `%s' ambiguous",
  86                                                    level);
  87                                 lev = ip6t_log_names[i].level;
  88                         }
  89                 }
  90
  91                 if (!set)
  92                         exit_error(PARAMETER_PROBLEM,
  93                                    "log-level `%s' unknown", level);
  94         }
  95
  96         return (u_int8_t)lev;
  97 }
  98
  99 #define IP6T_LOG_OPT_LEVEL 0x01
 100 #define IP6T_LOG_OPT_PREFIX 0x02
 101 #define IP6T_LOG_OPT_TCPSEQ 0x04
 102 #define IP6T_LOG_OPT_TCPOPT 0x08
 103 #define IP6T_LOG_OPT_IPOPT 0x10
 104 #define IP6T_LOG_OPT_UID 0x20
 105
 106 /* Function which parses command options; returns true if it
 107    ate an option */
 108 static int LOG_parse(int c, char **argv, int invert, unsigned int *flags,
 109                      const void *entry, struct xt_entry_target **target)
 110 {
 111         struct ip6t_log_info *loginfo = (struct ip6t_log_info *)(*target)->data;
 112
 113         switch (c) {
 114         case '!':
 115                 if (*flags & IP6T_LOG_OPT_LEVEL)
 116                         exit_error(PARAMETER_PROBLEM,
 117                                    "Can't specify --log-level twice");
 118
 119                 if (check_inverse(optarg, &invert, NULL, 0))
 120                         exit_error(PARAMETER_PROBLEM,
 121                                    "Unexpected `!' after --log-level");
 122
 123                 loginfo->level = parse_level(optarg);
 124                 *flags |= IP6T_LOG_OPT_LEVEL;
 125                 break;
 126
 127         case '#':
 128                 if (*flags & IP6T_LOG_OPT_PREFIX)
 129                         exit_error(PARAMETER_PROBLEM,
 130                                    "Can't specify --log-prefix twice");
 131
 132                 if (check_inverse(optarg, &invert, NULL, 0))
 133                         exit_error(PARAMETER_PROBLEM,
 134                                    "Unexpected `!' after --log-prefix");
 135
 136                 if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
 137                         exit_error(PARAMETER_PROBLEM,
 138                                    "Maximum prefix length %u for --log-prefix",
 139                                    (unsigned int)sizeof(loginfo->prefix) - 1);
 140
 141                 if (strlen(optarg) == 0)
 142                         exit_error(PARAMETER_PROBLEM,
 143                                    "No prefix specified for --log-prefix");
 144
 145                 if (strlen(optarg) != strlen(strtok(optarg, "\n")))
 146                         exit_error(PARAMETER_PROBLEM,
 147                                    "Newlines not allowed in --log-prefix");
 148
 149                 strcpy(loginfo->prefix, optarg);
 150                 *flags |= IP6T_LOG_OPT_PREFIX;
 151                 break;
 152
 153         case '1':
 154                 if (*flags & IP6T_LOG_OPT_TCPSEQ)
 155                         exit_error(PARAMETER_PROBLEM,
 156                                    "Can't specify --log-tcp-sequence "
 157                                    "twice");
 158
 159                 loginfo->logflags |= IP6T_LOG_TCPSEQ;
 160                 *flags |= IP6T_LOG_OPT_TCPSEQ;
 161                 break;
 162
 163         case '2':
 164                 if (*flags & IP6T_LOG_OPT_TCPOPT)
 165                         exit_error(PARAMETER_PROBLEM,
 166                                    "Can't specify --log-tcp-options twice");
 167
 168                 loginfo->logflags |= IP6T_LOG_TCPOPT;
 169                 *flags |= IP6T_LOG_OPT_TCPOPT;
 170                 break;
 171
 172         case '3':
 173                 if (*flags & IP6T_LOG_OPT_IPOPT)
 174                         exit_error(PARAMETER_PROBLEM,
 175                                    "Can't specify --log-ip-options twice");
 176
 177                 loginfo->logflags |= IP6T_LOG_IPOPT;
 178                 *flags |= IP6T_LOG_OPT_IPOPT;
 179                 break;
 180
 181         case '4':
 182                 if (*flags & IP6T_LOG_OPT_UID)
 183                         exit_error(PARAMETER_PROBLEM,
 184                                    "Can't specify --log-uid twice");
 185
 186                 loginfo->logflags |= IP6T_LOG_UID;
 187                 *flags |= IP6T_LOG_OPT_UID;
 188                 break;
 189
 190         default:
 191                 return 0;
 192         }
 193
 194         return 1;
 195 }
 196
 197 /* Prints out the targinfo. */
 198 static void LOG_print(const void *ip, const struct xt_entry_target *target,
 199                       int numeric)
 200 {
 201         const struct ip6t_log_info *loginfo
 202                 = (const struct ip6t_log_info *)target->data;
 203         unsigned int i = 0;
 204
 205         printf("LOG ");
 206         if (numeric)
 207                 printf("flags %u level %u ",
 208                        loginfo->logflags, loginfo->level);
 209         else {
 210                 for (i = 0;
 211                      i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
 212                      i++) {
 213                         if (loginfo->level == ip6t_log_names[i].level) {
 214                                 printf("level %s ", ip6t_log_names[i].name);
 215                                 break;
 216                         }
 217                 }
 218                 if (i == sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names))
 219                         printf("UNKNOWN level %u ", loginfo->level);
 220                 if (loginfo->logflags & IP6T_LOG_TCPSEQ)
 221                         printf("tcp-sequence ");
 222                 if (loginfo->logflags & IP6T_LOG_TCPOPT)
 223                         printf("tcp-options ");
 224                 if (loginfo->logflags & IP6T_LOG_IPOPT)
 225                         printf("ip-options ");
 226                 if (loginfo->logflags & IP6T_LOG_UID)
 227                         printf("uid ");
 228                 if (loginfo->logflags & ~(IP6T_LOG_MASK))
 229                         printf("unknown-flags ");
 230         }
 231
 232         if (strcmp(loginfo->prefix, "") != 0)
 233                 printf("prefix `%s' ", loginfo->prefix);
 234 }
 235
 236 /* Saves the union ip6t_targinfo in parsable form to stdout. */
 237 static void LOG_save(const void *ip, const struct xt_entry_target *target)
 238 {
 239         const struct ip6t_log_info *loginfo
 240                 = (const struct ip6t_log_info *)target->data;
 241
 242         if (strcmp(loginfo->prefix, "") != 0)
 243                 printf("--log-prefix \"%s\" ", loginfo->prefix);
 244
 245         if (loginfo->level != LOG_DEFAULT_LEVEL)
 246                 printf("--log-level %d ", loginfo->level);
 247
 248         if (loginfo->logflags & IP6T_LOG_TCPSEQ)
 249                 printf("--log-tcp-sequence ");
 250         if (loginfo->logflags & IP6T_LOG_TCPOPT)
 251                 printf("--log-tcp-options ");
 252         if (loginfo->logflags & IP6T_LOG_IPOPT)
 253                 printf("--log-ip-options ");
 254         if (loginfo->logflags & IP6T_LOG_UID)
 255                 printf("--log-uid ");
 256 }
 257
 258 static struct xtables_target log_tg6_reg = {
 259     .name          = "LOG",
 260     .version       = XTABLES_VERSION,
 261     .family        = PF_INET6,
 262     .size          = XT_ALIGN(sizeof(struct ip6t_log_info)),
 263     .userspacesize = XT_ALIGN(sizeof(struct ip6t_log_info)),
 264     .help          = LOG_help,
 265     .init          = LOG_init,
 266     .parse         = LOG_parse,
 267     .print         = LOG_print,
 268     .save          = LOG_save,
 269     .extra_opts    = LOG_opts,
 270 };
 271
 272 void _init(void)
 273 {
 274         xtables_register_target(&log_tg6_reg);
 275 }