You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
113 lines
2.7 KiB
113 lines
2.7 KiB
/* Shared library add-on to iptables to add static NAT support. |
|
Author: Svenning Soerensen <svenning@post5.tele.dk> |
|
*/ |
|
#include <stdio.h> |
|
#include <netdb.h> |
|
#include <string.h> |
|
#include <stdlib.h> |
|
#include <getopt.h> |
|
#include <xtables.h> |
|
#include <linux/netfilter/nf_nat.h> |
|
|
|
#define MODULENAME "NETMAP" |
|
|
|
enum { |
|
O_TO = 0, |
|
}; |
|
|
|
static const struct xt_option_entry NETMAP_opts[] = { |
|
{.name = "to", .id = O_TO, .type = XTTYPE_HOSTMASK, |
|
.flags = XTOPT_MAND}, |
|
XTOPT_TABLEEND, |
|
}; |
|
|
|
static void NETMAP_help(void) |
|
{ |
|
printf(MODULENAME" target options:\n" |
|
" --%s address[/mask]\n" |
|
" Network address to map to.\n\n", |
|
NETMAP_opts[0].name); |
|
} |
|
|
|
static int |
|
netmask2bits(uint32_t netmask) |
|
{ |
|
uint32_t bm; |
|
int bits; |
|
|
|
netmask = ntohl(netmask); |
|
for (bits = 0, bm = 0x80000000; netmask & bm; netmask <<= 1) |
|
bits++; |
|
if (netmask) |
|
return -1; /* holes in netmask */ |
|
return bits; |
|
} |
|
|
|
static void NETMAP_init(struct xt_entry_target *t) |
|
{ |
|
struct nf_nat_ipv4_multi_range_compat *mr = (struct nf_nat_ipv4_multi_range_compat *)t->data; |
|
|
|
/* Actually, it's 0, but it's ignored at the moment. */ |
|
mr->rangesize = 1; |
|
} |
|
|
|
static void NETMAP_parse(struct xt_option_call *cb) |
|
{ |
|
struct nf_nat_ipv4_multi_range_compat *mr = cb->data; |
|
struct nf_nat_ipv4_range *range = &mr->range[0]; |
|
|
|
xtables_option_parse(cb); |
|
range->flags |= NF_NAT_RANGE_MAP_IPS; |
|
range->min_ip = cb->val.haddr.ip & cb->val.hmask.ip; |
|
range->max_ip = range->min_ip | ~cb->val.hmask.ip; |
|
} |
|
|
|
static void __NETMAP_print(const void *ip, const struct xt_entry_target *target, |
|
int numeric) |
|
{ |
|
const struct nf_nat_ipv4_multi_range_compat *mr = (const void *)target->data; |
|
const struct nf_nat_ipv4_range *r = &mr->range[0]; |
|
struct in_addr a; |
|
int bits; |
|
|
|
a.s_addr = r->min_ip; |
|
printf("%s", xtables_ipaddr_to_numeric(&a)); |
|
a.s_addr = ~(r->min_ip ^ r->max_ip); |
|
bits = netmask2bits(a.s_addr); |
|
if (bits < 0) |
|
printf("/%s", xtables_ipaddr_to_numeric(&a)); |
|
else |
|
printf("/%d", bits); |
|
} |
|
|
|
static void NETMAP_print(const void *ip, const struct xt_entry_target *target, |
|
int numeric) |
|
{ |
|
printf(" to:"); |
|
__NETMAP_print(ip, target, numeric); |
|
} |
|
|
|
static void NETMAP_save(const void *ip, const struct xt_entry_target *target) |
|
{ |
|
printf(" --%s ", NETMAP_opts[0].name); |
|
__NETMAP_print(ip, target, 0); |
|
} |
|
|
|
static struct xtables_target netmap_tg_reg = { |
|
.name = MODULENAME, |
|
.version = XTABLES_VERSION, |
|
.family = NFPROTO_IPV4, |
|
.size = XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat)), |
|
.userspacesize = XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat)), |
|
.help = NETMAP_help, |
|
.init = NETMAP_init, |
|
.x6_parse = NETMAP_parse, |
|
.print = NETMAP_print, |
|
.save = NETMAP_save, |
|
.x6_options = NETMAP_opts, |
|
}; |
|
|
|
void _init(void) |
|
{ |
|
xtables_register_target(&netmap_tg_reg); |
|
}
|
|
|