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/* Provides a NETLINK target, identical to that of the ipchains -o flag */
/* AUTHOR: Gianni Tedesco <gianni@ecsc.co.uk> */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <syslog.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_NETLINK.h>
static void help(void)
{
printf("NETLINK v%s options:\n"
" --nldrop Drop the packet too\n"
" --nlmark <number> Mark the packet\n"
" --nlsize <bytes> Limit packet size\n",
IPTABLES_VERSION);
}
static struct option opts[] = {
{"nldrop", 0, 0, 'd'},
{"nlmark", 1, 0, 'm'},
{"nlsize", 1, 0, 's'},
{0}
};
static void init(struct ipt_entry_target *t, unsigned int *nfcache)
{
struct ipt_nldata *nld = (struct ipt_nldata *) t->data;
nld->flags=0;
*nfcache |= NFC_UNKNOWN;
}
/* Parse command options */
static int parse(int c, char **argv, int invert, unsigned int *flags,
const struct ipt_entry *entry,
struct ipt_entry_target **target)
{
struct ipt_nldata *nld=(struct ipt_nldata *)(*target)->data;
switch (c) {
case 'd':
if (MASK(*flags, USE_DROP))
exit_error(PARAMETER_PROBLEM,
"Can't specify --nldrop twice");
if ( check_inverse(optarg, &invert, NULL, 0) ) {
MASK_UNSET(nld->flags, USE_DROP);
} else {
MASK_SET(nld->flags, USE_DROP);
}
MASK_SET(*flags, USE_DROP);
break;
case 'm':
if (MASK(*flags, USE_MARK))
exit_error(PARAMETER_PROBLEM,
"Can't specify --nlmark twice");
if (check_inverse(optarg, &invert, NULL, 0)) {
MASK_UNSET(nld->flags, USE_MARK);
}else{
MASK_SET(nld->flags, USE_MARK);
nld->mark=atoi(optarg);
}
MASK_SET(*flags, USE_MARK);
break;
case 's':
if (MASK(*flags, USE_SIZE))
exit_error(PARAMETER_PROBLEM,
"Can't specify --nlsize twice");
if ( atoi(optarg) <= 0 )
exit_error(PARAMETER_PROBLEM,
"--nlsize must be larger than zero");
if (check_inverse(optarg, &invert, NULL, 0)) {
MASK_UNSET(nld->flags, USE_SIZE);
}else{
MASK_SET(nld->flags, USE_SIZE);
nld->size=atoi(optarg);
}
MASK_SET(*flags, USE_SIZE);
break;
default:
return 0;
}
return 1;
}
static void final_check(unsigned int flags)
{
/* ?? */
}
/* Saves the union ipt_targinfo in parsable form to stdout. */
static void save(const struct ipt_ip *ip,
const struct ipt_entry_target *target)
{
const struct ipt_nldata *nld
= (const struct ipt_nldata *) target->data;
if ( MASK(nld->flags, USE_DROP) )
printf("--nldrop ");
if ( MASK(nld->flags, USE_MARK) )
printf("--nlmark %i ", nld->mark);
if ( MASK(nld->flags, USE_SIZE) )
printf("--nlsize %i ", nld->size);
}
/* Prints out the targinfo. */
static void
print(const struct ipt_ip *ip,
const struct ipt_entry_target *target, int numeric)
{
const struct ipt_nldata *nld
= (const struct ipt_nldata *) target->data;
if ( MASK(nld->flags, USE_DROP) )
printf("nldrop ");
if ( MASK(nld->flags, USE_MARK) )
printf("nlmark %i ", nld->mark);
if ( MASK(nld->flags, USE_SIZE) )
printf("nlsize %i ", nld->size);
}
static struct iptables_target netlink = {
.next = NULL,
.name = "NETLINK",
.version = IPTABLES_VERSION,
.size = IPT_ALIGN(sizeof(struct ipt_nldata)),
.userspacesize = IPT_ALIGN(sizeof(struct ipt_nldata)),
.help = &help,
.init = &init,
.parse = &parse,
.final_check = &final_check,
.print = &print,
.save = &save,
.extra_opts = opts
};
void _init(void)
{
register_target(&netlink);
}
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