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

   1 /* Shared library add-on to iptables to add ROUTE target support.
   2  * Author : Cedric de Launois, <delaunois@info.ucl.ac.be>
   3  * v 1.11 2004/11/23
   4  */
   5
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <stdlib.h>
   9 #include <getopt.h>
  10 #include <net/if.h>
  11 #include <sys/socket.h>
  12 #include <netinet/in.h>
  13 #include <arpa/inet.h>
  14
  15 #include <iptables.h>
  16 #include <linux/netfilter_ipv4/ip_tables.h>
  17 #include <linux/netfilter_ipv4/ipt_ROUTE.h>
  18
  19 #ifndef XTABLES_VERSION
  20 #define XTABLES_VERSION IPTABLES_VERSION
  21 #endif
  22
  23 #ifdef IPT_LIB_DIR
  24 #define xtables_target iptables_target
  25 #define xtables_register_target register_target
  26 #endif
  27
  28 /* compile IPT_ROUTE_TEE support even if kernel headers are unpatched */
  29 #ifndef IPT_ROUTE_TEE
  30 #define IPT_ROUTE_TEE           0x02
  31 #endif
  32
  33 /* Function which prints out usage message. */
  34 static void
  35 help(void)
  36 {
  37         printf(
  38 "ROUTE target v%s options:\n"
  39 "    --oif   \tifname \t\tRoute packet through `ifname' network interface\n"
  40 "    --iif   \tifname \t\tChange packet's incoming interface to `ifname'\n"
  41 "    --gw    \tip     \t\tRoute packet via this gateway `ip'\n"
  42 "    --continue\t     \t\tRoute packet and continue traversing the\n"
  43 "            \t       \t\trules. Not valid with --iif or --tee.\n"
  44 "    --tee\t  \t\tDuplicate packet, route the duplicate,\n"
  45 "            \t       \t\tcontinue traversing with original packet.\n"
  46 "            \t       \t\tNot valid with --iif or --continue.\n"
  47 "\n",
  48 "1.11");
  49 }
  50
  51 static struct option opts[] = {
  52         { "oif", 1, 0, '1' },
  53         { "iif", 1, 0, '2' },
  54         { "gw", 1, 0, '3' },
  55         { "continue", 0, 0, '4' },
  56         { "tee", 0, 0, '5' },
  57         { 0 }
  58 };
  59
  60 /* Initialize the target. */
  61 static void
  62 #ifdef _XTABLES_H
  63 init(struct xt_entry_target *t)
  64 #else
  65 init(struct ipt_entry_target *t, unsigned int *nfcache)
  66 #endif
  67 {
  68         struct ipt_route_target_info *route_info =
  69                 (struct ipt_route_target_info*)t->data;
  70
  71         route_info->oif[0] = '\0';
  72         route_info->iif[0] = '\0';
  73         route_info->gw = 0;
  74         route_info->flags = 0;
  75 }
  76
  77
  78 #define IPT_ROUTE_OPT_OIF      0x01
  79 #define IPT_ROUTE_OPT_IIF      0x02
  80 #define IPT_ROUTE_OPT_GW       0x04
  81 #define IPT_ROUTE_OPT_CONTINUE 0x08
  82 #define IPT_ROUTE_OPT_TEE      0x10
  83
  84 /* Function which parses command options; returns true if it
  85    ate an option */
  86 static int
  87 parse(int c, char **argv, int invert, unsigned int *flags,
  88 #ifdef _XTABLES_H
  89       const void *entry, struct xt_entry_target **target)
  90 #else
  91       const struct ipt_entry *entry, struct ipt_entry_target **target)
  92 #endif
  93 {
  94         struct ipt_route_target_info *route_info =
  95                 (struct ipt_route_target_info*)(*target)->data;
  96
  97         switch (c) {
  98         case '1':
  99                 if (*flags & IPT_ROUTE_OPT_OIF)
 100                         exit_error(PARAMETER_PROBLEM,
 101                                    "Can't specify --oif twice");
 102
 103                 if (*flags & IPT_ROUTE_OPT_IIF)
 104                         exit_error(PARAMETER_PROBLEM,
 105                                    "Can't use --oif and --iif together");
 106
 107                 if (check_inverse(optarg, &invert, NULL, 0))
 108                         exit_error(PARAMETER_PROBLEM,
 109                                    "Unexpected `!' after --oif");
 110
 111                 if (strlen(optarg) > sizeof(route_info->oif) - 1)
 112                         exit_error(PARAMETER_PROBLEM,
 113                                    "Maximum interface name length %u",
 114                                    sizeof(route_info->oif) - 1);
 115
 116                 strcpy(route_info->oif, optarg);
 117                 *flags |= IPT_ROUTE_OPT_OIF;
 118                 break;
 119
 120         case '2':
 121                 if (*flags & IPT_ROUTE_OPT_IIF)
 122                         exit_error(PARAMETER_PROBLEM,
 123                                    "Can't specify --iif twice");
 124
 125                 if (*flags & IPT_ROUTE_OPT_OIF)
 126                         exit_error(PARAMETER_PROBLEM,
 127                                    "Can't use --iif and --oif together");
 128
 129                 if (check_inverse(optarg, &invert, NULL, 0))
 130                         exit_error(PARAMETER_PROBLEM,
 131                                    "Unexpected `!' after --iif");
 132
 133                 if (strlen(optarg) > sizeof(route_info->iif) - 1)
 134                         exit_error(PARAMETER_PROBLEM,
 135                                    "Maximum interface name length %u",
 136                                    sizeof(route_info->iif) - 1);
 137
 138                 strcpy(route_info->iif, optarg);
 139                 *flags |= IPT_ROUTE_OPT_IIF;
 140                 break;
 141
 142         case '3':
 143                 if (*flags & IPT_ROUTE_OPT_GW)
 144                         exit_error(PARAMETER_PROBLEM,
 145                                    "Can't specify --gw twice");
 146
 147                 if (check_inverse(optarg, &invert, NULL, 0))
 148                         exit_error(PARAMETER_PROBLEM,
 149                                    "Unexpected `!' after --gw");
 150
 151                 if (!inet_aton(optarg, (struct in_addr*)&route_info->gw)) {
 152                         exit_error(PARAMETER_PROBLEM,
 153                                    "Invalid IP address %s",
 154                                    optarg);
 155                 }
 156
 157                 *flags |= IPT_ROUTE_OPT_GW;
 158                 break;
 159
 160         case '4':
 161                 if (*flags & IPT_ROUTE_OPT_CONTINUE)
 162                         exit_error(PARAMETER_PROBLEM,
 163                                    "Can't specify --continue twice");
 164                 if (*flags & IPT_ROUTE_OPT_TEE)
 165                         exit_error(PARAMETER_PROBLEM,
 166                                    "Can't specify --continue AND --tee");
 167
 168                 route_info->flags |= IPT_ROUTE_CONTINUE;
 169                 *flags |= IPT_ROUTE_OPT_CONTINUE;
 170
 171                 break;
 172
 173         case '5':
 174                 if (*flags & IPT_ROUTE_OPT_TEE)
 175                         exit_error(PARAMETER_PROBLEM,
 176                                    "Can't specify --tee twice");
 177                 if (*flags & IPT_ROUTE_OPT_CONTINUE)
 178                         exit_error(PARAMETER_PROBLEM,
 179                                    "Can't specify --tee AND --continue");
 180
 181                 route_info->flags |= IPT_ROUTE_TEE;
 182                 *flags |= IPT_ROUTE_OPT_TEE;
 183
 184                 break;
 185
 186         default:
 187                 return 0;
 188         }
 189
 190         return 1;
 191 }
 192
 193
 194 static void
 195 final_check(unsigned int flags)
 196 {
 197         if (!flags)
 198                 exit_error(PARAMETER_PROBLEM,
 199                            "ROUTE target: oif, iif or gw option required");
 200
 201         if ((flags & (IPT_ROUTE_OPT_CONTINUE|IPT_ROUTE_OPT_TEE)) && (flags & IPT_ROUTE_OPT_IIF))
 202                 exit_error(PARAMETER_PROBLEM,
 203                            "ROUTE target: can't continue traversing the rules with iif option");
 204 }
 205
 206
 207 /* Prints out the targinfo. */
 208 static void
 209 #ifdef _XTABLES_H
 210 print(const void *ip,
 211       const struct xt_entry_target *target,
 212 #else
 213 print(const struct ipt_ip *ip,
 214       const struct ipt_entry_target *target,
 215 #endif
 216       int numeric)
 217 {
 218         const struct ipt_route_target_info *route_info
 219                 = (const struct ipt_route_target_info *)target->data;
 220
 221         printf("ROUTE ");
 222
 223         if (route_info->oif[0])
 224                 printf("oif:%s ", route_info->oif);
 225
 226         if (route_info->iif[0])
 227                 printf("iif:%s ", route_info->iif);
 228
 229         if (route_info->gw) {
 230                 struct in_addr gw = { route_info->gw };
 231                 printf("gw:%s ", inet_ntoa(gw));
 232         }
 233
 234         if (route_info->flags & IPT_ROUTE_CONTINUE)
 235                 printf("continue");
 236
 237         if (route_info->flags & IPT_ROUTE_TEE)
 238                 printf("tee");
 239
 240 }
 241
 242 static void
 243 #ifdef _XTABLES_H
 244 save(const void *ip,
 245      const struct xt_entry_target *target)
 246 #else
 247 save(const struct ipt_ip *ip,
 248      const struct ipt_entry_target *target)
 249 #endif
 250 {
 251         const struct ipt_route_target_info *route_info
 252                 = (const struct ipt_route_target_info *)target->data;
 253
 254         if (route_info->oif[0])
 255                 printf("--oif %s ", route_info->oif);
 256
 257         if (route_info->iif[0])
 258                 printf("--iif %s ", route_info->iif);
 259
 260         if (route_info->gw) {
 261                 struct in_addr gw = { route_info->gw };
 262                 printf("--gw %s ", inet_ntoa(gw));
 263         }
 264
 265         if (route_info->flags & IPT_ROUTE_CONTINUE)
 266                 printf("--continue ");
 267
 268         if (route_info->flags & IPT_ROUTE_TEE)
 269                 printf("--tee ");
 270 }
 271
 272
 273 static struct xtables_target route = {
 274         .next           = NULL,
 275         .name           = "ROUTE",
 276         .version        = XTABLES_VERSION,
 277         .size           = IPT_ALIGN(sizeof(struct ipt_route_target_info)),
 278         .userspacesize  = IPT_ALIGN(sizeof(struct ipt_route_target_info)),
 279         .help           = &help,
 280         .init           = &init,
 281         .parse          = &parse,
 282         .final_check    = &final_check,
 283         .print          = &print,
 284         .save           = &save,
 285         .extra_opts     = opts
 286 };
 287
 288 void _init(void)
 289 {
 290         xtables_register_target(&route);
 291 }