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/*
* Shared library add-on to iptables to add TPROXY target support.
*
* Copyright (C) 2002-2008 BalaBit IT Ltd.
*/
#include <getopt.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <iptables.h>
#include <xtables.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_TPROXY.h>
static const struct option tproxy_tg_opts[] = {
{ .name = "on-port", .has_arg = 1, .val = '1'},
{ .name = "on-ip", .has_arg = 1, .val = '2'},
{ .name = "tproxy-mark", .has_arg = 1, .val = '3'},
{NULL},
};
enum {
PARAM_ONPORT = 1 << 0,
PARAM_ONIP = 1 << 1,
PARAM_MARK = 1 << 2,
};
static void tproxy_tg_help(void)
{
printf(
"TPROXY target options:\n"
" --on-port port Redirect connection to port, or the original port if 0\n"
" --on-ip ip Optionally redirect to the given IP\n"
" --tproxy-mark value[/mask] Mark packets with the given value/mask\n\n");
}
static void parse_tproxy_lport(const char *s, struct xt_tproxy_target_info *info)
{
unsigned int lport;
if (string_to_number(s, 0, 65535, &lport) != -1)
info->lport = htons(lport);
else
param_act(P_BAD_VALUE, "TPROXY", "--on-port", s);
}
static void parse_tproxy_laddr(const char *s, struct xt_tproxy_target_info *info)
{
struct in_addr *laddr;
if ((laddr = numeric_to_ipaddr(s)) == NULL)
param_act(P_BAD_VALUE, "TPROXY", "--on-ip", s);
info->laddr = laddr->s_addr;
}
static void parse_tproxy_mark(char *s, struct xt_tproxy_target_info *info)
{
unsigned int value, mask = ~0U;
char *end;
if (!strtonum(s, &end, &value, 0, UINT_MAX))
param_act(P_BAD_VALUE, "TPROXY", "--tproxy-mark", s);
if (*end == '/')
if (!strtonum(end + 1, &end, &mask, 0, UINT_MAX))
param_act(P_BAD_VALUE, "TPROXY", "--tproxy-mark", s);
if (*end != '\0')
param_act(P_BAD_VALUE, "TPROXY", "--tproxy-mark", s);
info->mark_mask = mask;
info->mark_value = value;
}
static int tproxy_tg_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_target **target)
{
struct xt_tproxy_target_info *tproxyinfo = (void *)(*target)->data;
switch (c) {
case '1':
param_act(P_ONLY_ONCE, "TPROXY", "--on-port", *flags & PARAM_ONPORT);
param_act(P_NO_INVERT, "TPROXY", "--on-port", invert);
parse_tproxy_lport(optarg, tproxyinfo);
*flags |= PARAM_ONPORT;
return 1;
case '2':
param_act(P_ONLY_ONCE, "TPROXY", "--on-ip", *flags & PARAM_ONIP);
param_act(P_NO_INVERT, "TPROXY", "--on-ip", invert);
parse_tproxy_laddr(optarg, tproxyinfo);
*flags |= PARAM_ONIP;
return 1;
case '3':
param_act(P_ONLY_ONCE, "TPROXY", "--tproxy-mark", *flags & PARAM_MARK);
param_act(P_NO_INVERT, "TPROXY", "--tproxy-mark", invert);
parse_tproxy_mark(optarg, tproxyinfo);
*flags |= PARAM_MARK;
return 1;
}
return 0;
}
static void tproxy_tg_check(unsigned int flags)
{
if (!(flags & PARAM_ONPORT))
exit_error(PARAMETER_PROBLEM,
"TPROXY target: Parameter --on-port is required");
}
static void tproxy_tg_print(const void *ip, const struct xt_entry_target *target,
int numeric)
{
const struct xt_tproxy_target_info *info = (const void *)target->data;
printf("TPROXY redirect %s:%u mark 0x%x/0x%x",
ipaddr_to_numeric((const struct in_addr *)&info->laddr),
ntohs(info->lport), (unsigned int)info->mark_value,
(unsigned int)info->mark_mask);
}
static void tproxy_tg_save(const void *ip, const struct xt_entry_target *target)
{
const struct xt_tproxy_target_info *info = (const void *)target->data;
printf("--on-port %u ", ntohs(info->lport));
printf("--on-ip %s ",
ipaddr_to_numeric((const struct in_addr *)&info->laddr));
printf("--tproxy-mark 0x%x/0x%x ",
(unsigned int)info->mark_value, (unsigned int)info->mark_mask);
}
static struct xtables_target tproxy_tg_reg = {
.name = "TPROXY",
.family = AF_INET,
.version = XTABLES_VERSION,
.size = XT_ALIGN(sizeof(struct xt_tproxy_target_info)),
.userspacesize = XT_ALIGN(sizeof(struct xt_tproxy_target_info)),
.help = tproxy_tg_help,
.parse = tproxy_tg_parse,
.final_check = tproxy_tg_check,
.print = tproxy_tg_print,
.save = tproxy_tg_save,
.extra_opts = tproxy_tg_opts,
};
void _init(void)
{
xtables_register_target(&tproxy_tg_reg);
}
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