// Sasa Spasic
// (c) 2003.

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <net/if.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>


int
list_ifaces(int sock_fd)
{
    struct ifconf ifc;
    struct ifreq *ifr = NULL;
    int if_len = 0;
    int num_ifreq_items = 10;  // Pretpostavka da ce 10 adresa da bude dovoljno

    for (;;) {
	ifc.ifc_len = sizeof(struct ifreq) * num_ifreq_items;
	ifc.ifc_buf = malloc(ifc.ifc_len);
	if (NULL == ifc.ifc_buf) {
	    perror("malloc");
	    free(ifc.ifc_buf);
	    return -1;
	}

	if (ioctl(sock_fd, SIOCGIFCONF, &ifc) < 0) {
	    perror("ioctl(SIOCGIFCONF)");
	    free(ifc.ifc_buf);
	    return -1;
	}

	if (ifc.ifc_len == sizeof(struct ifreq) * num_ifreq_items) {
	    /* Mozda ipak nije bilo dovoljno mesta?
	       Uvecaj buffer za 10 mesta i probaj ponovo */
	    num_ifreq_items += 10;
	    free(ifc.ifc_buf);
	} else {
	    break;
	}
    }

    ifr = ifc.ifc_req;
    for (if_len = 0;
	 if_len < ifc.ifc_len;
	 if_len += sizeof(struct ifreq), ++ifr) {

	struct sockaddr_in *sin = (struct sockaddr_in *)&ifr->ifr_addr;

	printf("%s %s\n",
	       ifr->ifr_name,
	       inet_ntoa(sin->sin_addr));
    }

    free(ifc.ifc_buf);

    return 0;
}

int
main(int argc, char *argv[]) {
    int sock_fd = 0;
    int ret = 0;

    sock_fd = socket(PF_INET, SOCK_DGRAM, 0);
    if (sock_fd < 0) {
	perror("socket");
	exit(-1);
    }

    ret = list_ifaces(sock_fd);

    close(sock_fd);

    exit(ret);
}