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#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <getopt.h>
#include <xtables.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_NFLOG.h>
enum {
NFLOG_GROUP = 0x1,
NFLOG_PREFIX = 0x2,
NFLOG_RANGE = 0x4,
NFLOG_THRESHOLD = 0x8,
};
static const struct option NFLOG_opts[] = {
{.name = "nflog-group", .has_arg = true, .val = NFLOG_GROUP},
{.name = "nflog-prefix", .has_arg = true, .val = NFLOG_PREFIX},
{.name = "nflog-range", .has_arg = true, .val = NFLOG_RANGE},
{.name = "nflog-threshold", .has_arg = true, .val = NFLOG_THRESHOLD},
XT_GETOPT_TABLEEND,
};
static void NFLOG_help(void)
{
printf("NFLOG target options:\n"
" --nflog-group NUM NETLINK group used for logging\n"
" --nflog-range NUM Number of byte to copy\n"
" --nflog-threshold NUM Message threshold of in-kernel queue\n"
" --nflog-prefix STRING Prefix string for log messages\n");
}
static void NFLOG_init(struct xt_entry_target *t)
{
struct xt_nflog_info *info = (struct xt_nflog_info *)t->data;
info->threshold = XT_NFLOG_DEFAULT_THRESHOLD;
}
static int NFLOG_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_target **target)
{
struct xt_nflog_info *info = (struct xt_nflog_info *)(*target)->data;
int n;
size_t length;
switch (c) {
case NFLOG_GROUP:
if (*flags & NFLOG_GROUP)
xtables_error(PARAMETER_PROBLEM,
"Can't specify --nflog-group twice");
if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
xtables_error(PARAMETER_PROBLEM,
"Unexpected `!' after --nflog-group");
n = atoi(optarg);
if (n < 0)
xtables_error(PARAMETER_PROBLEM,
"--nflog-group can not be negative");
info->group = n;
break;
case NFLOG_PREFIX:
if (*flags & NFLOG_PREFIX)
xtables_error(PARAMETER_PROBLEM,
"Can't specify --nflog-prefix twice");
if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
xtables_error(PARAMETER_PROBLEM,
"Unexpected `!' after --nflog-prefix");
length = strlen(optarg);
if (length == 0)
xtables_error(PARAMETER_PROBLEM,
"No prefix specified for --nflog-prefix");
if (length >= sizeof(info->prefix))
xtables_error(PARAMETER_PROBLEM,
"--nflog-prefix too long, max %Zu characters",
sizeof(info->prefix) - 1);
if (length != strlen(strtok(optarg, "\n")))
xtables_error(PARAMETER_PROBLEM,
"Newlines are not allowed in --nflog-prefix");
strcpy(info->prefix, optarg);
break;
case NFLOG_RANGE:
if (*flags & NFLOG_RANGE)
xtables_error(PARAMETER_PROBLEM,
"Can't specify --nflog-range twice");
n = atoi(optarg);
if (n < 0)
xtables_error(PARAMETER_PROBLEM,
"Invalid --nflog-range, must be >= 0");
info->len = n;
break;
case NFLOG_THRESHOLD:
if (*flags & NFLOG_THRESHOLD)
xtables_error(PARAMETER_PROBLEM,
"Can't specify --nflog-threshold twice");
n = atoi(optarg);
if (n < 1)
xtables_error(PARAMETER_PROBLEM,
"Invalid --nflog-threshold, must be >= 1");
info->threshold = n;
break;
}
*flags |= c;
return 1;
}
static void nflog_print(const struct xt_nflog_info *info, char *prefix)
{
if (info->prefix[0] != '\0') {
printf(" %snflog-prefix ", prefix);
xtables_save_string(info->prefix);
}
if (info->group)
printf(" %snflog-group %u", prefix, info->group);
if (info->len)
printf(" %snflog-range %u", prefix, info->len);
if (info->threshold != XT_NFLOG_DEFAULT_THRESHOLD)
printf(" %snflog-threshold %u", prefix, info->threshold);
}
static void NFLOG_print(const void *ip, const struct xt_entry_target *target,
int numeric)
{
const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
nflog_print(info, "");
}
static void NFLOG_save(const void *ip, const struct xt_entry_target *target)
{
const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
nflog_print(info, "--");
}
static struct xtables_target nflog_target = {
.family = NFPROTO_UNSPEC,
.name = "NFLOG",
.version = XTABLES_VERSION,
.size = XT_ALIGN(sizeof(struct xt_nflog_info)),
.userspacesize = XT_ALIGN(sizeof(struct xt_nflog_info)),
.help = NFLOG_help,
.init = NFLOG_init,
.parse = NFLOG_parse,
.print = NFLOG_print,
.save = NFLOG_save,
.extra_opts = NFLOG_opts,
};
void _init(void)
{
xtables_register_target(&nflog_target);
}
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