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/* ebt_limit
*
* Authors:
* Tom Marshall <tommy@home.tig-grr.com>
*
* Mostly copied from iptables' limit match.
*
* September, 2003
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <errno.h>
#include "../include/ebtables_u.h"
#include <linux/netfilter_bridge/ebt_limit.h>
#define EBT_LIMIT_AVG "3/hour"
#define EBT_LIMIT_BURST 5
static int string_to_number(const char *s, unsigned int min, unsigned int max,
unsigned int *ret)
{
long number;
char *end;
errno = 0;
number = strtol(s, &end, 0);
if (*end == '\0' && end != s) {
if (errno != ERANGE && min <= number && number <= max) {
*ret = number;
return 0;
}
}
return -1;
}
#define FLAG_LIMIT 0x01
#define FLAG_LIMIT_BURST 0x02
#define ARG_LIMIT '1'
#define ARG_LIMIT_BURST '2'
static const struct option opts[] =
{
{ "limit", required_argument, 0, ARG_LIMIT },
{ "limit-burst", required_argument, 0, ARG_LIMIT_BURST },
{ 0 }
};
static void 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;
}
/* Initialize the match. */
static void init(struct ebt_entry_match *m)
{
struct ebt_limit_info *r = (struct ebt_limit_info *)m->data;
parse_rate(EBT_LIMIT_AVG, &r->avg);
r->burst = EBT_LIMIT_BURST;
}
/* FIXME: handle overflow:
if (r->avg*r->burst/r->burst != r->avg)
exit_error(PARAMETER_PROBLEM,
"Sorry: burst too large for that avg rate.\n");
*/
static int parse(int c, char **argv, int argc,
const struct ebt_u_entry *entry,
unsigned int *flags,
struct ebt_entry_match **match)
{
struct ebt_limit_info *r = (struct ebt_limit_info *)(*match)->data;
unsigned int num;
switch(c) {
case ARG_LIMIT:
ebt_check_option2(flags, FLAG_LIMIT);
if (ebt_check_inverse2(optarg))
ebt_print_error2("Unexpected `!' after --limit");
if (!parse_rate(optarg, &r->avg))
ebt_print_error2("bad rate `%s'", optarg);
break;
case ARG_LIMIT_BURST:
ebt_check_option2(flags, FLAG_LIMIT_BURST);
if (ebt_check_inverse2(optarg))
ebt_print_error2("Unexpected `!' after --limit-burst");
if (string_to_number(optarg, 0, 10000, &num) == -1)
ebt_print_error2("bad --limit-burst `%s'", optarg);
r->burst = num;
break;
default:
return 0;
}
return 1;
}
static void final_check(const struct ebt_u_entry *entry,
const struct ebt_entry_match *match, const char *name,
unsigned int hookmask, unsigned int time)
{
}
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 print(const struct ebt_u_entry *entry,
const struct ebt_entry_match *match)
{
struct ebt_limit_info *r = (struct ebt_limit_info *)match->data;
printf("--limit ");
print_rate(r->avg);
printf("--limit-burst %u ", r->burst);
}
static int compare(const struct ebt_entry_match* m1,
const struct ebt_entry_match *m2)
{
struct ebt_limit_info* li1 = (struct ebt_limit_info*)m1->data;
struct ebt_limit_info* li2 = (struct ebt_limit_info*)m2->data;
if (li1->avg != li2->avg)
return 0;
if (li1->burst != li2->burst)
return 0;
return 1;
}
static struct ebt_u_match limit_match =
{
.name = "limit",
.size = sizeof(struct ebt_limit_info),
.help = print_help,
.init = init,
.parse = parse,
.final_check = final_check,
.print = print,
.compare = compare,
.extra_ops = opts,
};
static void _INIT(void)
{
ebt_register_match(&limit_match);
}
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