diff options
Diffstat (limited to 'extensions/ebt_nat.c')
| -rw-r--r-- | extensions/ebt_nat.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/extensions/ebt_nat.c b/extensions/ebt_nat.c new file mode 100644 index 0000000..dbdb5a4 --- /dev/null +++ b/extensions/ebt_nat.c @@ -0,0 +1,222 @@ +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <linux/netfilter_bridge/ebtables.h> +#include <getopt.h> +#include "../include/ebtables_u.h" +#include <linux/netfilter_bridge/ebt_nat.h> + +extern char *standard_targets[NUM_STANDARD_TARGETS]; + +int to_source_supplied, to_dest_supplied; + +#define NAT_S '1' +#define NAT_D '1' +#define NAT_S_TARGET '2' +#define NAT_D_TARGET '2' +static struct option opts_s[] = +{ + { "to-source" , required_argument, 0, NAT_S }, + { "to-src" , required_argument, 0, NAT_S }, + { "snat-target" , required_argument, 0, NAT_S_TARGET }, + { 0 } +}; + +static struct option opts_d[] = +{ + { "to-destination", required_argument, 0, NAT_D }, + { "to-dst" , required_argument, 0, NAT_D }, + { "dnat-target" , required_argument, 0, NAT_D_TARGET }, + { 0 } +}; + +static void print_help_s() +{ + printf( + "snat options:\n" + " --to-src address : MAC address to map source to\n" + " --snat-target target : ACCEPT, DROP or CONTINUE\n"); +} + +static void print_help_d() +{ + printf( + "dnat options:\n" + " --to-dst address : MAC address to map destination to\n" + " --dnat-target target : ACCEPT, DROP or CONTINUE\n"); +} + +static void init_s(struct ebt_entry_target *target) +{ + struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data; + + to_source_supplied = 0; + natinfo->target = EBT_ACCEPT; + return; +} + +static void init_d(struct ebt_entry_target *target) +{ + struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data; + + to_dest_supplied = 0; + natinfo->target = EBT_ACCEPT; + return; +} + +#define OPT_SNAT 0x01 +#define OPT_SNAT_TARGET 0x02 +static int parse_s(int c, char **argv, int argc, + const struct ebt_u_entry *entry, unsigned int *flags, + struct ebt_entry_target **target) +{ + int i; + struct ebt_nat_info *natinfo = (struct ebt_nat_info *)(*target)->data; + + switch (c) { + case NAT_S: + check_option(flags, OPT_SNAT); + to_source_supplied = 1; + if (getmac(optarg, natinfo->mac)) + print_error("Problem with specified to-source mac"); + break; + case NAT_S_TARGET: + check_option(flags, OPT_SNAT_TARGET); + for (i = 0; i < NUM_STANDARD_TARGETS; i++) + if (!strcmp(optarg, standard_targets[i])) { + natinfo->target = i; + break; + } + if (i == NUM_STANDARD_TARGETS) + print_error("Illegal --snat-target target"); + break; + default: + return 0; + } + return 1; +} + +#define OPT_DNAT 0x01 +#define OPT_DNAT_TARGET 0x02 +static int parse_d(int c, char **argv, int argc, + const struct ebt_u_entry *entry, unsigned int *flags, + struct ebt_entry_target **target) +{ + int i; + struct ebt_nat_info *natinfo = (struct ebt_nat_info *)(*target)->data; + + switch (c) { + case NAT_D: + check_option(flags, OPT_DNAT); + to_dest_supplied = 1; + if (getmac(optarg, natinfo->mac)) + print_error("Problem with specified " + "to-destination mac"); + break; + case NAT_D_TARGET: + check_option(flags, OPT_DNAT_TARGET); + for (i = 0; i < NUM_STANDARD_TARGETS; i++) + if (!strcmp(optarg, standard_targets[i])) { + natinfo->target = i; + break; + } + if (i == NUM_STANDARD_TARGETS) + print_error("Illegal --dnat-target target"); + break; + default: + return 0; + } + return 1; +} + +static void final_check_s(const struct ebt_u_entry *entry, + const struct ebt_entry_target *target, const char *name, unsigned int hook) +{ + if (hook != NF_BR_POST_ROUTING || strcmp(name, "nat")) + print_error("Wrong chain for snat"); + if (to_source_supplied == 0) + print_error("No snat address supplied"); +} + +static void final_check_d(const struct ebt_u_entry *entry, + const struct ebt_entry_target *target, const char *name, unsigned int hook) +{ + if ( ((hook != NF_BR_PRE_ROUTING && hook != NF_BR_LOCAL_OUT) || + strcmp(name, "nat")) && + (hook != NF_BR_BROUTING || strcmp(name, "broute")) ) + print_error("Wrong chain for dnat"); + if (to_dest_supplied == 0) + print_error("No dnat address supplied"); +} + +static void print_s(const struct ebt_u_entry *entry, + const struct ebt_entry_target *target) +{ + struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data; + int i; + + printf("snat - to: "); + for (i = 0; i < ETH_ALEN; i++) + printf("%02x%s", + natinfo->mac[i], (i == ETH_ALEN - 1) ? "" : ":"); + printf(" --snat-target %s", standard_targets[natinfo->target]); +} + +static void print_d(const struct ebt_u_entry *entry, + const struct ebt_entry_target *target) +{ + struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data; + int i; + + printf("dnat - to: "); + for (i = 0; i < ETH_ALEN; i++) + printf("%02x%s", + natinfo->mac[i], (i == ETH_ALEN - 1) ? "" : ":"); + printf(" --dnat-target %s", standard_targets[natinfo->target]); +} + +static int compare(const struct ebt_entry_target *t1, + const struct ebt_entry_target *t2) +{ + struct ebt_nat_info *natinfo1 = (struct ebt_nat_info *)t1->data; + struct ebt_nat_info *natinfo2 = (struct ebt_nat_info *)t2->data; + + + return !memcmp(natinfo1->mac, natinfo2->mac, sizeof(natinfo1->mac)) && + natinfo1->target == natinfo2->target; +} + +static struct ebt_u_target snat_target = +{ + EBT_SNAT_TARGET, + sizeof(struct ebt_nat_info), + print_help_s, + init_s, + parse_s, + final_check_s, + print_s, + compare, + opts_s, +}; + +static struct ebt_u_target dnat_target = +{ + EBT_DNAT_TARGET, + sizeof(struct ebt_nat_info), + print_help_d, + init_d, + parse_d, + final_check_d, + print_d, + compare, + opts_d, +}; + +static void _init(void) __attribute__ ((constructor)); +static void _init(void) +{ + register_target(&snat_target); + register_target(&dnat_target); +} |