release/src/router/iptables/extensions/libipt_recent.c

   1 /* Shared library add-on to iptables to add recent matching support. */
   2 #include <stdio.h>
   3 #include <netdb.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <getopt.h>
   7
   8 #include <iptables.h>
   9 #include <linux/netfilter_ipv4/ipt_recent.h>
  10
  11 /* Need these in order to not fail when compiling against an older kernel. */
  12 #ifndef RECENT_NAME
  13 #define RECENT_NAME     "ipt_recent"
  14 #endif /* RECENT_NAME */
  15
  16 #ifndef RECENT_VER
  17 #define RECENT_VER      "unknown"
  18 #endif /* RECENT_VER */
  19
  20 #ifndef IPT_RECENT_NAME_LEN
  21 #define IPT_RECENT_NAME_LEN     200
  22 #endif /* IPT_RECENT_NAME_LEN */
  23
  24 /* Options for this module */
  25 static struct option opts[] = {
  26         { .name = "set",      .has_arg = 0, .flag = 0, .val = 201 },
  27         { .name = "rcheck",   .has_arg = 0, .flag = 0, .val = 202 },
  28         { .name = "update",   .has_arg = 0, .flag = 0, .val = 203 },
  29         { .name = "seconds",  .has_arg = 1, .flag = 0, .val = 204 },
  30         { .name = "hitcount", .has_arg = 1, .flag = 0, .val = 205 },
  31         { .name = "remove",   .has_arg = 0, .flag = 0, .val = 206 },
  32         { .name = "rttl",     .has_arg = 0, .flag = 0, .val = 207 },
  33         { .name = "name",     .has_arg = 1, .flag = 0, .val = 208 },
  34         { .name = "rsource",  .has_arg = 0, .flag = 0, .val = 209 },
  35         { .name = "rdest",    .has_arg = 0, .flag = 0, .val = 210 },
  36         { .name = 0,          .has_arg = 0, .flag = 0, .val = 0   }
  37 };
  38
  39 /* Function which prints out usage message. */
  40 static void
  41 help(void)
  42 {
  43         printf(
  44 "recent v%s options:\n"
  45 "[!] --set                       Add source address to list, always matches.\n"
  46 "[!] --rcheck                    Match if source address in list.\n"
  47 "[!] --update                    Match if source address in list, also update last-seen time.\n"
  48 "[!] --remove                    Match if source address in list, also removes that address from list.\n"
  49 "    --seconds seconds           For check and update commands above.\n"
  50 "                                Specifies that the match will only occur if source address last seen within\n"
  51 "                                the last 'seconds' seconds.\n"
  52 "    --hitcount hits             For check and update commands above.\n"
  53 "                                Specifies that the match will only occur if source address seen hits times.\n"
  54 "                                May be used in conjunction with the seconds option.\n"
  55 "    --rttl                      For check and update commands above.\n"
  56 "                                Specifies that the match will only occur if the source address and the TTL\n"
  57 "                                match between this packet and the one which was set.\n"
  58 "                                Useful if you have problems with people spoofing their source address in order\n"
  59 "                                to DoS you via this module.\n"
  60 "    --name name                 Name of the recent list to be used.  DEFAULT used if none given.\n"
  61 "    --rsource                   Match/Save the source address of each packet in the recent list table (default).\n"
  62 "    --rdest                     Match/Save the destination address of each packet in the recent list table.\n"
  63 RECENT_NAME " " RECENT_VER ": Stephen Frost <sfrost@snowman.net>.  http://snowman.net/projects/ipt_recent/\n"
  64 ,
  65 IPTABLES_VERSION);
  66
  67 }
  68
  69 /* Initialize the match. */
  70 static void
  71 init(struct ipt_entry_match *match, unsigned int *nfcache)
  72 {
  73         struct ipt_recent_info *info = (struct ipt_recent_info *)(match)->data;
  74
  75
  76         strncpy(info->name,"DEFAULT",IPT_RECENT_NAME_LEN);
  77         /* eventhough IPT_RECENT_NAME_LEN is currently defined as 200,
  78          * better be safe, than sorry */
  79         info->name[IPT_RECENT_NAME_LEN-1] = '\0';
  80         info->side = IPT_RECENT_SOURCE;
  81 }
  82
  83 /* Function which parses command options; returns true if it
  84    ate an option */
  85 static int
  86 parse(int c, char **argv, int invert, unsigned int *flags,
  87       const struct ipt_entry *entry,
  88       unsigned int *nfcache,
  89       struct ipt_entry_match **match)
  90 {
  91         struct ipt_recent_info *info = (struct ipt_recent_info *)(*match)->data;
  92         switch (c) {
  93                 case 201:
  94                         if (*flags) exit_error(PARAMETER_PROBLEM,
  95                                         "recent: only one of `--set', `--rcheck' "
  96                                         "`--update' or `--remove' may be set");
  97                         check_inverse(optarg, &invert, &optind, 0);
  98                         info->check_set |= IPT_RECENT_SET;
  99                         if (invert) info->invert = 1;
 100                         *flags = 1;
 101                         break;
 102
 103                 case 202:
 104                         if (*flags) exit_error(PARAMETER_PROBLEM,
 105                                         "recent: only one of `--set', `--rcheck' "
 106                                         "`--update' or `--remove' may be set");
 107                         check_inverse(optarg, &invert, &optind, 0);
 108                         info->check_set |= IPT_RECENT_CHECK;
 109                         if(invert) info->invert = 1;
 110                         *flags = 1;
 111                         break;
 112
 113                 case 203:
 114                         if (*flags) exit_error(PARAMETER_PROBLEM,
 115                                         "recent: only one of `--set', `--rcheck' "
 116                                         "`--update' or `--remove' may be set");
 117                         check_inverse(optarg, &invert, &optind, 0);
 118                         info->check_set |= IPT_RECENT_UPDATE;
 119                         if (invert) info->invert = 1;
 120                         *flags = 1;
 121                         break;
 122
 123                 case 206:
 124                         if (*flags) exit_error(PARAMETER_PROBLEM,
 125                                         "recent: only one of `--set', `--rcheck' "
 126                                         "`--update' or `--remove' may be set");
 127                         check_inverse(optarg, &invert, &optind, 0);
 128                         info->check_set |= IPT_RECENT_REMOVE;
 129                         if (invert) info->invert = 1;
 130                         *flags = 1;
 131                         break;
 132
 133                 case 204:
 134                         info->seconds = atoi(optarg);
 135                         break;
 136
 137                 case 205:
 138                         info->hit_count = atoi(optarg);
 139                         break;
 140
 141                 case 207:
 142                         info->check_set |= IPT_RECENT_TTL;
 143                         break;
 144
 145                 case 208:
 146                         strncpy(info->name,optarg,IPT_RECENT_NAME_LEN);
 147                         info->name[IPT_RECENT_NAME_LEN-1] = '\0';
 148                         break;
 149
 150                 case 209:
 151                         info->side = IPT_RECENT_SOURCE;
 152                         break;
 153
 154                 case 210:
 155                         info->side = IPT_RECENT_DEST;
 156                         break;
 157
 158                 default:
 159                         return 0;
 160         }
 161
 162         return 1;
 163 }
 164
 165 /* Final check; must have specified a specific option. */
 166 static void
 167 final_check(unsigned int flags)
 168 {
 169
 170         if (!flags)
 171                 exit_error(PARAMETER_PROBLEM,
 172                         "recent: you must specify one of `--set', `--rcheck' "
 173                         "`--update' or `--remove'");
 174 }
 175
 176 /* Prints out the matchinfo. */
 177 static void
 178 print(const struct ipt_ip *ip,
 179       const struct ipt_entry_match *match,
 180       int numeric)
 181 {
 182         struct ipt_recent_info *info = (struct ipt_recent_info *)match->data;
 183
 184         if (info->invert)
 185                 fputc('!', stdout);
 186
 187         printf("recent: ");
 188         if(info->check_set & IPT_RECENT_SET) printf("SET ");
 189         if(info->check_set & IPT_RECENT_CHECK) printf("CHECK ");
 190         if(info->check_set & IPT_RECENT_UPDATE) printf("UPDATE ");
 191         if(info->check_set & IPT_RECENT_REMOVE) printf("REMOVE ");
 192         if(info->seconds) printf("seconds: %d ",info->seconds);
 193         if(info->hit_count) printf("hit_count: %d ",info->hit_count);
 194         if(info->check_set & IPT_RECENT_TTL) printf("TTL-Match ");
 195         if(info->name) printf("name: %s ",info->name);
 196         if(info->side == IPT_RECENT_SOURCE) printf("side: source ");
 197         if(info->side == IPT_RECENT_DEST) printf("side: dest");
 198 }
 199
 200 /* Saves the union ipt_matchinfo in parsable form to stdout. */
 201 static void
 202 save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
 203 {
 204         struct ipt_recent_info *info = (struct ipt_recent_info *)match->data;
 205
 206         if (info->invert)
 207                 printf("! ");
 208
 209         if(info->check_set & IPT_RECENT_SET) printf("--set ");
 210         if(info->check_set & IPT_RECENT_CHECK) printf("--rcheck ");
 211         if(info->check_set & IPT_RECENT_UPDATE) printf("--update ");
 212         if(info->check_set & IPT_RECENT_REMOVE) printf("--remove ");
 213         if(info->seconds) printf("--seconds %d ",info->seconds);
 214         if(info->hit_count) printf("--hitcount %d ",info->hit_count);
 215         if(info->check_set & IPT_RECENT_TTL) printf("--rttl ");
 216         if(info->name) printf("--name %s ",info->name);
 217         if(info->side == IPT_RECENT_SOURCE) printf("--rsource ");
 218         if(info->side == IPT_RECENT_DEST) printf("--rdest ");
 219 }
 220
 221 /* Structure for iptables to use to communicate with module */
 222 static struct iptables_match recent = {
 223     .next          = NULL,
 224     .name          = "recent",
 225     .version       = IPTABLES_VERSION,
 226     .size          = IPT_ALIGN(sizeof(struct ipt_recent_info)),
 227     .userspacesize = IPT_ALIGN(sizeof(struct ipt_recent_info)),
 228     .help          = &help,
 229     .init          = &init,
 230     .parse         = &parse,
 231     .final_check   = &final_check,
 232     .print         = &print,
 233     .save          = &save,
 234     .extra_opts    = opts
 235 };
 236
 237 void _init(void)
 238 {
 239         register_match(&recent);
 240 }