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
  22 help(void)
  23 {
  24         printf(
  25 "LOG v%s options:\n"
  26 " --log-level level             Level of logging (numeric or see syslog.conf)\n"
  27 " --log-prefix prefix           Prefix log messages with this prefix.\n\n"
  28 " --log-tcp-sequence            Log TCP sequence numbers.\n\n"
  29 " --log-tcp-options             Log TCP options.\n\n"
  30 " --log-ip-options              Log IP options.\n\n"
  31 " --log-uid                     Log UID owning the local socket.\n\n",
  32 IPTABLES_VERSION);
  33 }
  34
  35 static struct option opts[] = {
  36         { .name = "log-level",        .has_arg = 1, .flag = 0, .val = '!' },
  37         { .name = "log-prefix",       .has_arg = 1, .flag = 0, .val = '#' },
  38         { .name = "log-tcp-sequence", .has_arg = 0, .flag = 0, .val = '1' },
  39         { .name = "log-tcp-options",  .has_arg = 0, .flag = 0, .val = '2' },
  40         { .name = "log-ip-options",   .has_arg = 0, .flag = 0, .val = '3' },
  41         { .name = "log-uid",          .has_arg = 0, .flag = 0, .val = '4' },
  42         { .name = 0 }
  43 };
  44
  45 /* Initialize the target. */
  46 static void
  47 init(struct ip6t_entry_target *t, unsigned int *nfcache)
  48 {
  49         struct ip6t_log_info *loginfo = (struct ip6t_log_info *)t->data;
  50
  51         loginfo->level = LOG_DEFAULT_LEVEL;
  52
  53 }
  54
  55 struct ip6t_log_names {
  56         const char *name;
  57         unsigned int level;
  58 };
  59
  60 static struct ip6t_log_names ip6t_log_names[]
  61 = { { .name = "alert",   .level = LOG_ALERT },
  62     { .name = "crit",    .level = LOG_CRIT },
  63     { .name = "debug",   .level = LOG_DEBUG },
  64     { .name = "emerg",   .level = LOG_EMERG },
  65     { .name = "error",   .level = LOG_ERR },            /* DEPRECATED */
  66     { .name = "info",    .level = LOG_INFO },
  67     { .name = "notice",  .level = LOG_NOTICE },
  68     { .name = "panic",   .level = LOG_EMERG },          /* DEPRECATED */
  69     { .name = "warning", .level = LOG_WARNING }
  70 };
  71
  72 static u_int8_t
  73 parse_level(const char *level)
  74 {
  75         unsigned int lev = -1;
  76         unsigned int set = 0;
  77
  78         if (string_to_number(level, 0, 7, &lev) == -1) {
  79                 unsigned int i = 0;
  80
  81                 for (i = 0;
  82                      i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
  83                      i++) {
  84                         if (strncasecmp(level, ip6t_log_names[i].name,
  85                                         strlen(level)) == 0) {
  86                                 if (set++)
  87                                         exit_error(PARAMETER_PROBLEM,
  88                                                    "log-level `%s' ambiguous",
  89                                                    level);
  90                                 lev = ip6t_log_names[i].level;
  91                         }
  92                 }
  93
  94                 if (!set)
  95                         exit_error(PARAMETER_PROBLEM,
  96                                    "log-level `%s' unknown", level);
  97         }
  98
  99         return (u_int8_t)lev;
 100 }
 101
 102 #define IP6T_LOG_OPT_LEVEL 0x01
 103 #define IP6T_LOG_OPT_PREFIX 0x02
 104 #define IP6T_LOG_OPT_TCPSEQ 0x04
 105 #define IP6T_LOG_OPT_TCPOPT 0x08
 106 #define IP6T_LOG_OPT_IPOPT 0x10
 107 #define IP6T_LOG_OPT_UID 0x20
 108
 109 /* Function which parses command options; returns true if it
 110    ate an option */
 111 static int
 112 parse(int c, char **argv, int invert, unsigned int *flags,
 113       const struct ip6t_entry *entry,
 114       struct ip6t_entry_target **target)
 115 {
 116         struct ip6t_log_info *loginfo = (struct ip6t_log_info *)(*target)->data;
 117
 118         switch (c) {
 119         case '!':
 120                 if (*flags & IP6T_LOG_OPT_LEVEL)
 121                         exit_error(PARAMETER_PROBLEM,
 122                                    "Can't specify --log-level twice");
 123
 124                 if (check_inverse(optarg, &invert, NULL, 0))
 125                         exit_error(PARAMETER_PROBLEM,
 126                                    "Unexpected `!' after --log-level");
 127
 128                 loginfo->level = parse_level(optarg);
 129                 *flags |= IP6T_LOG_OPT_LEVEL;
 130                 break;
 131
 132         case '#':
 133                 if (*flags & IP6T_LOG_OPT_PREFIX)
 134                         exit_error(PARAMETER_PROBLEM,
 135                                    "Can't specify --log-prefix twice");
 136
 137                 if (check_inverse(optarg, &invert, NULL, 0))
 138                         exit_error(PARAMETER_PROBLEM,
 139                                    "Unexpected `!' after --log-prefix");
 140
 141                 if (strlen(optarg) > sizeof(loginfo->prefix) - 1)
 142                         exit_error(PARAMETER_PROBLEM,
 143                                    "Maximum prefix length %u for --log-prefix",
 144                                    (unsigned int)sizeof(loginfo->prefix) - 1);
 145
 146                 if (strlen(optarg) != strlen(strtok(optarg, "\n")))
 147                         exit_error(PARAMETER_PROBLEM,
 148                                    "Newlines not allowed in --log-prefix");
 149
 150                 strcpy(loginfo->prefix, optarg);
 151                 *flags |= IP6T_LOG_OPT_PREFIX;
 152                 break;
 153
 154         case '1':
 155                 if (*flags & IP6T_LOG_OPT_TCPSEQ)
 156                         exit_error(PARAMETER_PROBLEM,
 157                                    "Can't specify --log-tcp-sequence "
 158                                    "twice");
 159
 160                 loginfo->logflags |= IP6T_LOG_TCPSEQ;
 161                 *flags |= IP6T_LOG_OPT_TCPSEQ;
 162                 break;
 163
 164         case '2':
 165                 if (*flags & IP6T_LOG_OPT_TCPOPT)
 166                         exit_error(PARAMETER_PROBLEM,
 167                                    "Can't specify --log-tcp-options twice");
 168
 169                 loginfo->logflags |= IP6T_LOG_TCPOPT;
 170                 *flags |= IP6T_LOG_OPT_TCPOPT;
 171                 break;
 172
 173         case '3':
 174                 if (*flags & IP6T_LOG_OPT_IPOPT)
 175                         exit_error(PARAMETER_PROBLEM,
 176                                    "Can't specify --log-ip-options twice");
 177
 178                 loginfo->logflags |= IP6T_LOG_IPOPT;
 179                 *flags |= IP6T_LOG_OPT_IPOPT;
 180                 break;
 181
 182         case '4':
 183                 if (*flags & IP6T_LOG_OPT_UID)
 184                         exit_error(PARAMETER_PROBLEM,
 185                                    "Can't specify --log-uid twice");
 186
 187                 loginfo->logflags |= IP6T_LOG_UID;
 188                 *flags |= IP6T_LOG_OPT_UID;
 189                 break;
 190
 191         default:
 192                 return 0;
 193         }
 194
 195         return 1;
 196 }
 197
 198 /* Final check; nothing. */
 199 static void final_check(unsigned int flags)
 200 {
 201 }
 202
 203 /* Prints out the targinfo. */
 204 static void
 205 print(const struct ip6t_ip6 *ip,
 206       const struct ip6t_entry_target *target,
 207       int numeric)
 208 {
 209         const struct ip6t_log_info *loginfo
 210                 = (const struct ip6t_log_info *)target->data;
 211         unsigned int i = 0;
 212
 213         printf("LOG ");
 214         if (numeric)
 215                 printf("flags %u level %u ",
 216                        loginfo->logflags, loginfo->level);
 217         else {
 218                 for (i = 0;
 219                      i < sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names);
 220                      i++) {
 221                         if (loginfo->level == ip6t_log_names[i].level) {
 222                                 printf("level %s ", ip6t_log_names[i].name);
 223                                 break;
 224                         }
 225                 }
 226                 if (i == sizeof(ip6t_log_names) / sizeof(struct ip6t_log_names))
 227                         printf("UNKNOWN level %u ", loginfo->level);
 228                 if (loginfo->logflags & IP6T_LOG_TCPSEQ)
 229                         printf("tcp-sequence ");
 230                 if (loginfo->logflags & IP6T_LOG_TCPOPT)
 231                         printf("tcp-options ");
 232                 if (loginfo->logflags & IP6T_LOG_IPOPT)
 233                         printf("ip-options ");
 234                 if (loginfo->logflags & IP6T_LOG_UID)
 235                         printf("uid ");
 236                 if (loginfo->logflags & ~(IP6T_LOG_MASK))
 237                         printf("unknown-flags ");
 238         }
 239
 240         if (strcmp(loginfo->prefix, "") != 0)
 241                 printf("prefix `%s' ", loginfo->prefix);
 242 }
 243
 244 /* Saves the union ip6t_targinfo in parsable form to stdout. */
 245 static void
 246 save(const struct ip6t_ip6 *ip, const struct ip6t_entry_target *target)
 247 {
 248         const struct ip6t_log_info *loginfo
 249                 = (const struct ip6t_log_info *)target->data;
 250
 251         if (strcmp(loginfo->prefix, "") != 0)
 252                 printf("--log-prefix \"%s\" ", loginfo->prefix);
 253
 254         if (loginfo->level != LOG_DEFAULT_LEVEL)
 255                 printf("--log-level %d ", loginfo->level);
 256
 257         if (loginfo->logflags & IP6T_LOG_TCPSEQ)
 258                 printf("--log-tcp-sequence ");
 259         if (loginfo->logflags & IP6T_LOG_TCPOPT)
 260                 printf("--log-tcp-options ");
 261         if (loginfo->logflags & IP6T_LOG_IPOPT)
 262                 printf("--log-ip-options ");
 263         if (loginfo->logflags & IP6T_LOG_UID)
 264                 printf("--log-uid ");
 265 }
 266
 267 static
 268 struct ip6tables_target log
 269 = {
 270     .name          = "LOG",
 271     .version       = IPTABLES_VERSION,
 272     .size          = IP6T_ALIGN(sizeof(struct ip6t_log_info)),
 273     .userspacesize = IP6T_ALIGN(sizeof(struct ip6t_log_info)),
 274     .help          = &help,
 275     .init          = &init,
 276     .parse         = &parse,
 277     .final_check   = &final_check,
 278     .print         = &print,
 279     .save          = &save,
 280     .extra_opts    = opts
 281 };
 282
 283 void _init(void)
 284 {
 285         register_target6(&log);
 286 }