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/* Shared library add-on to iptables to add recent matching support. */
#include <stdbool.h>
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <xtables.h>
#include <linux/netfilter/xt_recent.h>
static const struct option recent_opts[] = {
{.name = "set", .has_arg = false, .val = 201},
{.name = "rcheck", .has_arg = false, .val = 202},
{.name = "update", .has_arg = false, .val = 203},
{.name = "seconds", .has_arg = true, .val = 204},
{.name = "hitcount", .has_arg = true, .val = 205},
{.name = "remove", .has_arg = false, .val = 206},
{.name = "rttl", .has_arg = false, .val = 207},
{.name = "name", .has_arg = true, .val = 208},
{.name = "rsource", .has_arg = false, .val = 209},
{.name = "rdest", .has_arg = false, .val = 210},
XT_GETOPT_TABLEEND,
};
static void recent_help(void)
{
printf(
"recent match options:\n"
"[!] --set Add source address to list, always matches.\n"
"[!] --rcheck Match if source address in list.\n"
"[!] --update Match if source address in list, also update last-seen time.\n"
"[!] --remove Match if source address in list, also removes that address from list.\n"
" --seconds seconds For check and update commands above.\n"
" Specifies that the match will only occur if source address last seen within\n"
" the last 'seconds' seconds.\n"
" --hitcount hits For check and update commands above.\n"
" Specifies that the match will only occur if source address seen hits times.\n"
" May be used in conjunction with the seconds option.\n"
" --rttl For check and update commands above.\n"
" Specifies that the match will only occur if the source address and the TTL\n"
" match between this packet and the one which was set.\n"
" Useful if you have problems with people spoofing their source address in order\n"
" to DoS you via this module.\n"
" --name name Name of the recent list to be used. DEFAULT used if none given.\n"
" --rsource Match/Save the source address of each packet in the recent list table (default).\n"
" --rdest Match/Save the destination address of each packet in the recent list table.\n"
"xt_recent by: Stephen Frost <sfrost@snowman.net>. http://snowman.net/projects/ipt_recent/\n");
}
static void recent_init(struct xt_entry_match *match)
{
struct xt_recent_mtinfo *info = (void *)(match)->data;
strncpy(info->name,"DEFAULT", XT_RECENT_NAME_LEN);
/* even though XT_RECENT_NAME_LEN is currently defined as 200,
* better be safe, than sorry */
info->name[XT_RECENT_NAME_LEN-1] = '\0';
info->side = XT_RECENT_SOURCE;
}
#define RECENT_CMDS \
(XT_RECENT_SET | XT_RECENT_CHECK | \
XT_RECENT_UPDATE | XT_RECENT_REMOVE)
static int recent_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
struct xt_recent_mtinfo *info = (void *)(*match)->data;
switch (c) {
case 201:
if (*flags & RECENT_CMDS)
xtables_error(PARAMETER_PROBLEM,
"recent: only one of `--set', `--rcheck' "
"`--update' or `--remove' may be set");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
info->check_set |= XT_RECENT_SET;
if (invert) info->invert = 1;
*flags |= XT_RECENT_SET;
break;
case 202:
if (*flags & RECENT_CMDS)
xtables_error(PARAMETER_PROBLEM,
"recent: only one of `--set', `--rcheck' "
"`--update' or `--remove' may be set");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
info->check_set |= XT_RECENT_CHECK;
if(invert) info->invert = 1;
*flags |= XT_RECENT_CHECK;
break;
case 203:
if (*flags & RECENT_CMDS)
xtables_error(PARAMETER_PROBLEM,
"recent: only one of `--set', `--rcheck' "
"`--update' or `--remove' may be set");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
info->check_set |= XT_RECENT_UPDATE;
if (invert) info->invert = 1;
*flags |= XT_RECENT_UPDATE;
break;
case 204:
info->seconds = atoi(optarg);
break;
case 205:
info->hit_count = atoi(optarg);
break;
case 206:
if (*flags & RECENT_CMDS)
xtables_error(PARAMETER_PROBLEM,
"recent: only one of `--set', `--rcheck' "
"`--update' or `--remove' may be set");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
info->check_set |= XT_RECENT_REMOVE;
if (invert) info->invert = 1;
*flags |= XT_RECENT_REMOVE;
break;
case 207:
info->check_set |= XT_RECENT_TTL;
*flags |= XT_RECENT_TTL;
break;
case 208:
strncpy(info->name,optarg, XT_RECENT_NAME_LEN);
info->name[XT_RECENT_NAME_LEN-1] = '\0';
break;
case 209:
info->side = XT_RECENT_SOURCE;
break;
case 210:
info->side = XT_RECENT_DEST;
break;
}
return 1;
}
static void recent_check(unsigned int flags)
{
if (!(flags & RECENT_CMDS))
xtables_error(PARAMETER_PROBLEM,
"recent: you must specify one of `--set', `--rcheck' "
"`--update' or `--remove'");
if ((flags & XT_RECENT_TTL) &&
(flags & (XT_RECENT_SET | XT_RECENT_REMOVE)))
xtables_error(PARAMETER_PROBLEM,
"recent: --rttl may only be used with --rcheck or "
"--update");
}
static void recent_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct xt_recent_mtinfo *info = (const void *)match->data;
if (info->invert)
printf(" !");
printf(" recent:");
if (info->check_set & XT_RECENT_SET)
printf(" SET");
if (info->check_set & XT_RECENT_CHECK)
printf(" CHECK");
if (info->check_set & XT_RECENT_UPDATE)
printf(" UPDATE");
if (info->check_set & XT_RECENT_REMOVE)
printf(" REMOVE");
if(info->seconds) printf(" seconds: %d", info->seconds);
if(info->hit_count) printf(" hit_count: %d", info->hit_count);
if (info->check_set & XT_RECENT_TTL)
printf(" TTL-Match");
if(info->name) printf(" name: %s", info->name);
if (info->side == XT_RECENT_SOURCE)
printf(" side: source");
if (info->side == XT_RECENT_DEST)
printf(" side: dest");
}
static void recent_save(const void *ip, const struct xt_entry_match *match)
{
const struct xt_recent_mtinfo *info = (const void *)match->data;
if (info->invert)
printf(" !");
if (info->check_set & XT_RECENT_SET)
printf(" --set");
if (info->check_set & XT_RECENT_CHECK)
printf(" --rcheck");
if (info->check_set & XT_RECENT_UPDATE)
printf(" --update");
if (info->check_set & XT_RECENT_REMOVE)
printf(" --remove");
if(info->seconds) printf(" --seconds %d", info->seconds);
if(info->hit_count) printf(" --hitcount %d", info->hit_count);
if (info->check_set & XT_RECENT_TTL)
printf(" --rttl");
if(info->name) printf(" --name %s",info->name);
if (info->side == XT_RECENT_SOURCE)
printf(" --rsource");
if (info->side == XT_RECENT_DEST)
printf(" --rdest");
}
static struct xtables_match recent_mt_reg = {
.name = "recent",
.version = XTABLES_VERSION,
.family = NFPROTO_UNSPEC,
.size = XT_ALIGN(sizeof(struct xt_recent_mtinfo)),
.userspacesize = XT_ALIGN(sizeof(struct xt_recent_mtinfo)),
.help = recent_help,
.init = recent_init,
.parse = recent_parse,
.final_check = recent_check,
.print = recent_print,
.save = recent_save,
.extra_opts = recent_opts,
};
void _init(void)
{
xtables_register_match(&recent_mt_reg);
}
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