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#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter/xt_statistic.h>
static void
help(void)
{
printf(
"statistic match v%s options:\n"
" --mode mode Match mode (random, nth)\n"
" random mode:\n"
" --probability p Probability\n"
" nth mode:\n"
" --every n Match every nth packet\n"
" --packet p Initial counter value (0 <= p <= n-1, default 0)\n"
"\n",
IPTABLES_VERSION);
}
static struct option opts[] = {
{ "mode", 1, 0, '1' },
{ "probability", 1, 0, '2' },
{ "every", 1, 0, '3' },
{ "packet", 1, 0, '4' },
{ 0 }
};
static struct xt_statistic_info *info;
static int
parse(int c, char **argv, int invert, unsigned int *flags,
const struct ipt_entry *entry,
unsigned int *nfcache,
struct ipt_entry_match **match)
{
double prob;
info = (void *)(*match)->data;
if (invert)
info->flags |= XT_STATISTIC_INVERT;
switch (c) {
case '1':
if (*flags & 0x1)
exit_error(PARAMETER_PROBLEM, "double --mode");
if (!strcmp(optarg, "random"))
info->mode = XT_STATISTIC_MODE_RANDOM;
else if (!strcmp(optarg, "nth"))
info->mode = XT_STATISTIC_MODE_NTH;
else
exit_error(PARAMETER_PROBLEM, "Bad mode `%s'", optarg);
*flags |= 0x1;
break;
case '2':
if (*flags & 0x2)
exit_error(PARAMETER_PROBLEM, "double --probability");
prob = atof(optarg);
if (prob < 0 || prob > 1)
exit_error(PARAMETER_PROBLEM,
"--probability must be between 0 and 1");
info->u.random.probability = 0x80000000 * prob;
*flags |= 0x2;
break;
case '3':
if (*flags & 0x4)
exit_error(PARAMETER_PROBLEM, "double --every");
if (string_to_number(optarg, 0, 0xFFFFFFFF,
&info->u.nth.every) == -1)
exit_error(PARAMETER_PROBLEM,
"cannot parse --every `%s'", optarg);
if (info->u.nth.every == 0)
exit_error(PARAMETER_PROBLEM, "--every cannot be 0");
info->u.nth.every--;
*flags |= 0x4;
break;
case '4':
if (*flags & 0x8)
exit_error(PARAMETER_PROBLEM, "double --packet");
if (string_to_number(optarg, 0, 0xFFFFFFFF,
&info->u.nth.packet) == -1)
exit_error(PARAMETER_PROBLEM,
"cannot parse --packet `%s'", optarg);
*flags |= 0x8;
break;
default:
return 0;
}
return 1;
}
/* Final check; must have specified --mark. */
static void
final_check(unsigned int flags)
{
if (!(flags & 0x1))
exit_error(PARAMETER_PROBLEM, "no mode specified");
if ((flags & 0x2) && (flags & (0x4 | 0x8)))
exit_error(PARAMETER_PROBLEM,
"both nth and random parameters given");
if (flags & 0x2 && info->mode != XT_STATISTIC_MODE_RANDOM)
exit_error(PARAMETER_PROBLEM,
"--probability can only be used in random mode");
if (flags & 0x4 && info->mode != XT_STATISTIC_MODE_NTH)
exit_error(PARAMETER_PROBLEM,
"--every can only be used in nth mode");
if (flags & 0x8 && info->mode != XT_STATISTIC_MODE_NTH)
exit_error(PARAMETER_PROBLEM,
"--packet can only be used in nth mode");
info->u.nth.count = info->u.nth.every - info->u.nth.packet;
}
/* Prints out the matchinfo. */
static void print_match(const struct xt_statistic_info *info, char *prefix)
{
if (info->flags & XT_STATISTIC_INVERT)
printf("! ");
switch (info->mode) {
case XT_STATISTIC_MODE_RANDOM:
printf("%smode random %sprobability %f ", prefix, prefix,
1.0 * info->u.random.probability / 0x80000000);
break;
case XT_STATISTIC_MODE_NTH:
printf("%smode nth %severy %u ", prefix, prefix,
info->u.nth.every + 1);
if (info->u.nth.packet)
printf("%spacket %u ", prefix, info->u.nth.packet);
break;
}
}
static void
print(const struct ipt_ip *ip,
const struct ipt_entry_match *match,
int numeric)
{
struct xt_statistic_info *info = (struct xt_statistic_info *)match->data;
printf("statistic ");
print_match(info, "");
}
/* Saves the union ipt_matchinfo in parsable form to stdout. */
static void
save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
{
struct xt_statistic_info *info = (struct xt_statistic_info *)match->data;
print_match(info, "--");
}
static struct iptables_match statistic = {
.name = "statistic",
.version = IPTABLES_VERSION,
.size = IPT_ALIGN(sizeof(struct xt_statistic_info)),
.userspacesize = offsetof(struct xt_statistic_info, u.nth.count),
.help = help,
.parse = parse,
.final_check = final_check,
.print = print,
.save = save,
.extra_opts = opts
};
void _init(void)
{
register_match(&statistic);
}
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