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/* ebt_limit
*
* Authors:
* Tom Marshall <tommy@home.tig-grr.com>
*
* Mostly copied from iptables' limit match.
*
* September, 2003
*
* Translated to use libxtables for ebtables-compat in 2015 by
* Arturo Borrero Gonzalez <arturo@debian.org>
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <errno.h>
#include <xtables.h>
#include <linux/netfilter_bridge/ebt_limit.h>
#include "iptables/nft.h"
#include "iptables/nft-bridge.h"
#define EBT_LIMIT_AVG "3/hour"
#define EBT_LIMIT_BURST 5
#define FLAG_LIMIT 0x01
#define FLAG_LIMIT_BURST 0x02
#define ARG_LIMIT '1'
#define ARG_LIMIT_BURST '2'
static const struct option brlimit_opts[] =
{
{ .name = "limit", .has_arg = true, .val = ARG_LIMIT },
{ .name = "limit-burst",.has_arg = true, .val = ARG_LIMIT_BURST },
XT_GETOPT_TABLEEND,
};
static void brlimit_print_help(void)
{
printf(
"limit options:\n"
"--limit avg : max average match rate: default "EBT_LIMIT_AVG"\n"
" [Packets per second unless followed by \n"
" /sec /minute /hour /day postfixes]\n"
"--limit-burst number : number to match in a burst, -1 < number < 10001,\n"
" default %u\n", EBT_LIMIT_BURST);
}
static int parse_rate(const char *rate, uint32_t *val)
{
const char *delim;
uint32_t r;
uint32_t mult = 1; /* Seconds by default. */
delim = strchr(rate, '/');
if (delim) {
if (strlen(delim+1) == 0)
return 0;
if (strncasecmp(delim+1, "second", strlen(delim+1)) == 0)
mult = 1;
else if (strncasecmp(delim+1, "minute", strlen(delim+1)) == 0)
mult = 60;
else if (strncasecmp(delim+1, "hour", strlen(delim+1)) == 0)
mult = 60*60;
else if (strncasecmp(delim+1, "day", strlen(delim+1)) == 0)
mult = 24*60*60;
else
return 0;
}
r = atoi(rate);
if (!r)
return 0;
/* This would get mapped to infinite (1/day is minimum they
can specify, so we're ok at that end). */
if (r / mult > EBT_LIMIT_SCALE)
return 0;
*val = EBT_LIMIT_SCALE * mult / r;
return 1;
}
static void brlimit_init(struct xt_entry_match *match)
{
struct ebt_limit_info *r = (struct ebt_limit_info *)match->data;
parse_rate(EBT_LIMIT_AVG, &r->avg);
r->burst = EBT_LIMIT_BURST;
}
static int brlimit_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
struct ebt_limit_info *r = (struct ebt_limit_info *)(*match)->data;
uintmax_t num;
switch (c) {
case ARG_LIMIT:
EBT_CHECK_OPTION(flags, FLAG_LIMIT);
if (invert)
xtables_error(PARAMETER_PROBLEM,
"Unexpected `!' after --limit");
if (!parse_rate(optarg, &r->avg))
xtables_error(PARAMETER_PROBLEM,
"bad rate `%s'", optarg);
break;
case ARG_LIMIT_BURST:
EBT_CHECK_OPTION(flags, FLAG_LIMIT_BURST);
if (invert)
xtables_error(PARAMETER_PROBLEM,
"Unexpected `!' after --limit-burst");
if (!xtables_strtoul(optarg, NULL, &num, 0, 10000))
xtables_error(PARAMETER_PROBLEM,
"bad --limit-burst `%s'", optarg);
r->burst = num;
break;
default:
return 0;
}
return 1;
}
struct rates
{
const char *name;
uint32_t mult;
};
static struct rates g_rates[] =
{
{ "day", EBT_LIMIT_SCALE*24*60*60 },
{ "hour", EBT_LIMIT_SCALE*60*60 },
{ "min", EBT_LIMIT_SCALE*60 },
{ "sec", EBT_LIMIT_SCALE }
};
static void print_rate(uint32_t period)
{
unsigned int i;
for (i = 1; i < sizeof(g_rates)/sizeof(struct rates); i++)
if (period > g_rates[i].mult ||
g_rates[i].mult/period < g_rates[i].mult%period)
break;
printf("%u/%s ", g_rates[i-1].mult / period, g_rates[i-1].name);
}
static void brlimit_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
struct ebt_limit_info *r = (struct ebt_limit_info *)match->data;
printf("--limit ");
print_rate(r->avg);
printf("--limit-burst %u ", r->burst);
}
static struct xtables_match brlimit_match = {
.name = "limit",
.revision = 0,
.version = XTABLES_VERSION,
.family = NFPROTO_BRIDGE,
.size = XT_ALIGN(sizeof(struct ebt_limit_info)),
.userspacesize = offsetof(struct ebt_limit_info, prev),
.init = brlimit_init,
.help = brlimit_print_help,
.parse = brlimit_parse,
.print = brlimit_print,
.extra_opts = brlimit_opts,
};
void _init(void)
{
xtables_register_match(&brlimit_match);
}
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