unix_list.c

/*
 * MIT License
 *
 * Copyright (c) 2018 Lewis Van Winkle
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <sys/socket.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>


int main() {

    struct ifaddrs *addresses;

    if (getifaddrs(&addresses) == -1) {
        printf("getifaddrs call failed\n");
        return -1;
    }

    struct ifaddrs *address = addresses;
    while(address) {
        if (address->ifa_addr == NULL) { 
            address = address->ifa_next;
            continue;
        }
        int family = address->ifa_addr->sa_family;
        if (family == AF_INET || family == AF_INET6) {

            printf("%s\t", address->ifa_name);
            printf("%s\t", family == AF_INET ? "IPv4" : "IPv6");

            char ap[100];
            const int family_size = family == AF_INET ?
                sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6);
            getnameinfo(address->ifa_addr,
                    family_size, ap, sizeof(ap), 0, 0, NI_NUMERICHOST);
            printf("\t%s\n", ap);

        }
        address = address->ifa_next;
    }


    freeifaddrs(addresses);
    return 0;
}