release/src/router/ebtables/extensions/ebt_nat.c

   1 /* ebt_nat
   2  *
   3  * Authors:
   4  * Bart De Schuymer <bdschuym@pandora.be>
   5  *
   6  * June, 2002
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <getopt.h>
  13 #include "../include/ebtables_u.h"
  14 #include <netinet/ether.h>
  15 #include <linux/netfilter_bridge/ebt_nat.h>
  16
  17 static int to_source_supplied, to_dest_supplied;
  18
  19 #define NAT_S '1'
  20 #define NAT_D '1'
  21 #define NAT_S_TARGET '2'
  22 #define NAT_D_TARGET '2'
  23 #define NAT_S_ARP '3'
  24 static struct option opts_s[] =
  25 {
  26         { "to-source"     , required_argument, 0, NAT_S },
  27         { "to-src"        , required_argument, 0, NAT_S },
  28         { "snat-target"   , required_argument, 0, NAT_S_TARGET },
  29         { "snat-arp"      ,       no_argument, 0, NAT_S_ARP },
  30         { 0 }
  31 };
  32
  33 static struct option opts_d[] =
  34 {
  35         { "to-destination", required_argument, 0, NAT_D },
  36         { "to-dst"        , required_argument, 0, NAT_D },
  37         { "dnat-target"   , required_argument, 0, NAT_D_TARGET },
  38         { 0 }
  39 };
  40
  41 static void print_help_s()
  42 {
  43         printf(
  44         "snat options:\n"
  45         " --to-src address       : MAC address to map source to\n"
  46         " --snat-target target   : ACCEPT, DROP, RETURN or CONTINUE\n"
  47         " --snat-arp             : also change src address in arp msg\n");
  48 }
  49
  50 static void print_help_d()
  51 {
  52         printf(
  53         "dnat options:\n"
  54         " --to-dst address       : MAC address to map destination to\n"
  55         " --dnat-target target   : ACCEPT, DROP, RETURN or CONTINUE\n");
  56 }
  57
  58 static void init_s(struct ebt_entry_target *target)
  59 {
  60         struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data;
  61
  62         to_source_supplied = 0;
  63         natinfo->target = EBT_ACCEPT;
  64         return;
  65 }
  66
  67 static void init_d(struct ebt_entry_target *target)
  68 {
  69         struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data;
  70
  71         to_dest_supplied = 0;
  72         natinfo->target = EBT_ACCEPT;
  73         return;
  74 }
  75
  76 #define OPT_SNAT         0x01
  77 #define OPT_SNAT_TARGET  0x02
  78 #define OPT_SNAT_ARP     0x04
  79 static int parse_s(int c, char **argv, int argc,
  80    const struct ebt_u_entry *entry, unsigned int *flags,
  81    struct ebt_entry_target **target)
  82 {
  83         struct ebt_nat_info *natinfo = (struct ebt_nat_info *)(*target)->data;
  84         struct ether_addr *addr;
  85
  86         switch (c) {
  87         case NAT_S:
  88                 ebt_check_option2(flags, OPT_SNAT);
  89                 to_source_supplied = 1;
  90                 if (!(addr = ether_aton(optarg)))
  91                         ebt_print_error2("Problem with specified --to-source mac");
  92                 memcpy(natinfo->mac, addr, ETH_ALEN);
  93                 break;
  94         case NAT_S_TARGET:
  95                 { int tmp;
  96                 ebt_check_option2(flags, OPT_SNAT_TARGET);
  97                 if (FILL_TARGET(optarg, tmp))
  98                         ebt_print_error2("Illegal --snat-target target");
  99                 natinfo->target = (natinfo->target & ~EBT_VERDICT_BITS) | (tmp & EBT_VERDICT_BITS);
 100                 }
 101                 break;
 102         case NAT_S_ARP:
 103                 ebt_check_option2(flags, OPT_SNAT_ARP);
 104                 natinfo->target ^= NAT_ARP_BIT;
 105                 break;
 106         default:
 107                 return 0;
 108         }
 109         return 1;
 110 }
 111
 112 #define OPT_DNAT        0x01
 113 #define OPT_DNAT_TARGET 0x02
 114 static int parse_d(int c, char **argv, int argc,
 115    const struct ebt_u_entry *entry, unsigned int *flags,
 116    struct ebt_entry_target **target)
 117 {
 118         struct ebt_nat_info *natinfo = (struct ebt_nat_info *)(*target)->data;
 119         struct ether_addr *addr;
 120
 121         switch (c) {
 122         case NAT_D:
 123                 ebt_check_option2(flags, OPT_DNAT);
 124                 to_dest_supplied = 1;
 125                 if (!(addr = ether_aton(optarg)))
 126                         ebt_print_error2("Problem with specified --to-destination mac");
 127                 memcpy(natinfo->mac, addr, ETH_ALEN);
 128                 break;
 129         case NAT_D_TARGET:
 130                 ebt_check_option2(flags, OPT_DNAT_TARGET);
 131                 if (FILL_TARGET(optarg, natinfo->target))
 132                         ebt_print_error2("Illegal --dnat-target target");
 133                 break;
 134         default:
 135                 return 0;
 136         }
 137         return 1;
 138 }
 139
 140 static void final_check_s(const struct ebt_u_entry *entry,
 141    const struct ebt_entry_target *target, const char *name,
 142    unsigned int hookmask, unsigned int time)
 143 {
 144         struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data;
 145
 146         if (BASE_CHAIN && (natinfo->target | ~EBT_VERDICT_BITS) == EBT_RETURN) {
 147                 ebt_print_error("--snat-target RETURN not allowed on base chain");
 148                 return;
 149         }
 150         CLEAR_BASE_CHAIN_BIT;
 151         if ((hookmask & ~(1 << NF_BR_POST_ROUTING)) || strcmp(name, "nat")) {
 152                 ebt_print_error("Wrong chain for snat");
 153         } else if (time == 0 && to_source_supplied == 0)
 154                 ebt_print_error("No snat address supplied");
 155 }
 156
 157 static void final_check_d(const struct ebt_u_entry *entry,
 158    const struct ebt_entry_target *target, const char *name,
 159    unsigned int hookmask, unsigned int time)
 160 {
 161         struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data;
 162
 163         if (BASE_CHAIN && natinfo->target == EBT_RETURN) {
 164                 ebt_print_error("--dnat-target RETURN not allowed on base chain");
 165                 return;
 166         }
 167         CLEAR_BASE_CHAIN_BIT;
 168         if (((hookmask & ~((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT)))
 169            || strcmp(name, "nat")) &&
 170            ((hookmask & ~(1 << NF_BR_BROUTING)) || strcmp(name, "broute"))) {
 171                 ebt_print_error("Wrong chain for dnat");
 172         } else if (time == 0 && to_dest_supplied == 0)
 173                 ebt_print_error("No dnat address supplied");
 174 }
 175
 176 static void print_s(const struct ebt_u_entry *entry,
 177    const struct ebt_entry_target *target)
 178 {
 179         struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data;
 180
 181         printf("--to-src ");
 182         ebt_print_mac(natinfo->mac);
 183         if (!(natinfo->target&NAT_ARP_BIT))
 184                 printf(" --snat-arp");
 185         printf(" --snat-target %s", TARGET_NAME((natinfo->target|~EBT_VERDICT_BITS)));
 186 }
 187
 188 static void print_d(const struct ebt_u_entry *entry,
 189    const struct ebt_entry_target *target)
 190 {
 191         struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data;
 192
 193         printf("--to-dst ");
 194         ebt_print_mac(natinfo->mac);
 195         printf(" --dnat-target %s", TARGET_NAME(natinfo->target));
 196 }
 197
 198 static int compare(const struct ebt_entry_target *t1,
 199    const struct ebt_entry_target *t2)
 200 {
 201         struct ebt_nat_info *natinfo1 = (struct ebt_nat_info *)t1->data;
 202         struct ebt_nat_info *natinfo2 = (struct ebt_nat_info *)t2->data;
 203
 204         return !memcmp(natinfo1->mac, natinfo2->mac, sizeof(natinfo1->mac)) &&
 205            natinfo1->target == natinfo2->target;
 206 }
 207
 208 static struct ebt_u_target snat_target =
 209 {
 210         .name           = "snat",
 211         .size           = sizeof(struct ebt_nat_info),
 212         .help           = print_help_s,
 213         .init           = init_s,
 214         .parse          = parse_s,
 215         .final_check    = final_check_s,
 216         .print          = print_s,
 217         .compare        = compare,
 218         .extra_ops      = opts_s,
 219 };
 220
 221 static struct ebt_u_target dnat_target =
 222 {
 223         .name           = "dnat",
 224         .size           = sizeof(struct ebt_nat_info),
 225         .help           = print_help_d,
 226         .init           = init_d,
 227         .parse          = parse_d,
 228         .final_check    = final_check_d,
 229         .print          = print_d,
 230         .compare        = compare,
 231         .extra_ops      = opts_d,
 232 };
 233
 234 void _init(void)
 235 {
 236         ebt_register_target(&snat_target);
 237         ebt_register_target(&dnat_target);
 238 }