get_addr_info_test.c

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

int
main(int argc, char *argv[])
{
    struct ifaddrs *ifaddr, *ifa;
    int family, s;
    char host[NI_MAXHOST];

    if (getifaddrs(&ifaddr) == -1) {
        perror("getifaddrs");
        exit(EXIT_FAILURE);
    }

    /* Walk through linked list, maintaining head pointer so we
       can free list later */

    for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
        if (ifa->ifa_addr == NULL)
            continue;
/*
	if(!strcmp(ifa->ifa_name, "lo"))
		continue;
*/

        family = ifa->ifa_addr->sa_family;

        /* Display interface name and family (including symbolic
            form of the latter for the common families) */
#if 1
        printf("%s  address family: %d%s### ",
                ifa->ifa_name, family,
                (family == AF_PACKET) ? " (AF_PACKET)" :
                (family == AF_INET) ?   " (AF_INET)" :
                (family == AF_INET6) ?  " (AF_INET6)" : "");
        /* For an AF_INET* interface address, display the address */
#endif
        if (family == AF_INET || family == AF_INET6) {
            s = getnameinfo(ifa->ifa_addr,
                    (family == AF_INET) ? sizeof(struct sockaddr_in) :
                                          sizeof(struct sockaddr_in6),
                    host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
            if (s != 0) {
                printf("getnameinfo() failed: %s\n", gai_strerror(s));
                exit(EXIT_FAILURE);
            }
           printf("  address: <%s>", host);
        }
	printf("\n");
    }

    freeifaddrs(ifaddr);
    exit(EXIT_SUCCESS);
}