#include <sys/param.h>
#include <sys/socket.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int
main(void)
{
	struct rt_msghdr *rtm;
	struct sockaddr *sa;
	struct sockaddr_in *sin;

	int mib[7];
	size_t needed;
	char *pbuf, *next, *lim;

	mib[0] = CTL_NET;
	mib[1] = PF_ROUTE;
	mib[2] = 0;
	mib[3] = AF_INET;
	mib[4] = NET_RT_DUMP;
	mib[5] = 0;
	mib[6] = 0;

	if (sysctl(mib, 7, NULL, &needed, NULL, 0) < 0) {
		perror("sysctl");
		exit(1);
	}	
        if ((pbuf = (void*)calloc(needed, 1)) == NULL) {
                perror("calloc");
		exit(1);
        }
	if (sysctl(mib, 7, pbuf, &needed, NULL, 0) < 0) {
		perror("sysctl");
		exit(1);
	}	
	lim = pbuf + needed;

	for (next = pbuf; next < lim; next += rtm->rtm_msglen) {
		rtm = (struct rt_msghdr *)next;

		if (rtm->rtm_version != RTM_VERSION)
			continue;

		sa = (struct sockaddr *)(next + rtm->rtm_hdrlen);

                if (sa->sa_family != AF_INET)
			continue;

		if ((rtm->rtm_addrs & RTA_DST) && 
			(rtm->rtm_addrs & RTA_GATEWAY) &&
			(rtm->rtm_addrs & RTA_NETMASK)) {
			sin = (struct sockaddr_in *)(sa + RTAX_DST);
			printf("destination: %s\n", inet_ntoa(sin->sin_addr.s_addr));
			sin = (struct sockaddr_in *)(sa + RTAX_GATEWAY);
			printf("gateway: %s\n", inet_ntoa(sin->sin_addr.s_addr));
			sin = (struct sockaddr_in *)(sa + RTAX_NETMASK);
			printf("netmask: %s\n", inet_ntoa(sin->sin_addr.s_addr));
			printf("-----\n");
		}	

	}

	
}