/* Shared library add-on to iptables to add DEST target support. */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>

#include <iptables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <arpa/inet.h>


/* Function which prints out usage message. */
static void
help(void)
{
	printf(
		"DEST options:\n"
		" --to-destination <ip>:<port>\n\n"
	);
}

static struct option opts[] = {
	{ "to-destination", 1, 0, '1' },
	{ 0 }
};

/* Initialize the target. */
static void
init(struct ipt_entry_target *t, unsigned int *nfcache)
{
}

/* Function which parses command options; returns true if it
   ate an option */
static int
parse(int c, char **argv, int invert, unsigned int *flags,
      const struct ipt_entry *entry,
      struct ipt_entry_target **target)
{
	char *colon;
	struct sockaddr_in *sin = (void *) (*target)->data;
	int port = 65535;
		printf("%d, %s\n", c, optarg);
	switch(c)
	{
	case '1':
		colon = strchr(optarg, ':');
		if(colon)
		{
			port = atoi(colon+1);
			colon[0] = '\0';
		}
		sin->sin_port = htons(port);
		inet_aton(optarg, &(sin->sin_addr));
		fprintf(stderr, "%x %d\n", sin->sin_addr.s_addr , htons(sin->sin_port));
		*flags = 1;
		break;
	default:
		return 0;
	}
	return 1;
}

static void
final_check(unsigned int flags)
{
	if (!flags)
		exit_error(PARAMETER_PROBLEM,
			"You must specify --to-destination");
}

static void
print(const struct ipt_ip *ip,
      const struct ipt_entry_target *target,
      int numeric)
{
	struct sockaddr_in *sin = (struct sockaddr_in *)target->data;
	printf("to: %s:%d\n", inet_ntoa(sin->sin_addr), ntohs(sin->sin_port));
}

/* Saves the union ipt_targinfo in parsable form to stdout. */
static void
save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
{
	struct sockaddr_in *sin = (struct sockaddr_in *)target->data;

	printf("--to-destination %s:%d\n", inet_ntoa(sin->sin_addr), ntohs(sin->sin_port));
}

static
struct iptables_target dest 
= { .next = NULL,
    .name = "DEST",
    .version = IPTABLES_VERSION,
    .size = IPT_ALIGN(sizeof(struct sockaddr_in)),
    .userspacesize = IPT_ALIGN(sizeof(struct sockaddr_in)),
    .help = &help,
    .init = &init,
    .parse = &parse,
    .final_check = &final_check,
    .print = &print,
    .save = &save,
    .extra_opts = opts
};

void _init(void)
{
	register_target(&dest);
}