#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <net/if.h>
#include <ifaddrs.h>

void
print_addr(struct sockaddr *sa)
{
	int err;
	char host[NI_MAXHOST];

	if (sa == NULL) {
		printf("\n");
		return;
	}

	switch (sa->sa_family) {
	case AF_INET:
		err = getnameinfo(sa, sizeof(struct sockaddr_in),
				  host, sizeof(host), NULL, 0, NI_NUMERICHOST);
		if (err<0) {
			perror("getnameinfo");
			exit(EXIT_FAILURE);
		}
		break;
	case AF_INET6:
		err = getnameinfo(sa, sizeof(struct sockaddr_in6),
				  host, sizeof(host), NULL, 0, NI_NUMERICHOST);
		if (err<0) {
			perror("getnameinfo");
			exit(EXIT_FAILURE);
		}
		break;
	default:
		printf("\n");
		return;
	}

	printf("[%s]\n", host);
}

int
main(int argc, char **argv)
{
	struct ifaddrs *ifap0, *ifap;
	char buf[BUFSIZ];

	memset(buf, 0, sizeof(buf));

	if (getifaddrs(&ifap0)) {
		printf("err\n");
		goto fin;
	}

	for (ifap = ifap0; ifap; ifap=ifap->ifa_next) {
		if ( !(ifap->ifa_flags & IFF_UP)) {
			printf("skip\n");
			continue;
		}
		printf("Interface: %s\n", ifap->ifa_name);
		if (ifap->ifa_addr == NULL)
			continue;
		printf("\tAddress: ");
		print_addr(ifap->ifa_addr);
		printf("------\n");
	}		

fin:
	freeifaddrs(ifap);

	return 0;
}