/* $Id$ */
/* public domain */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void
usage()
{
        extern char *__progname;

        (void)fprintf(stderr, "usage: %s addr\n", __progname);
        exit(1);
}

int
main(int argc, char **argv)
{
        struct in_addr in4;
        struct in6_addr in6;

        char addr4[INET_ADDRSTRLEN];
        char addr6[INET6_ADDRSTRLEN];

        void *in;
        char *addr;
        int af;
        socklen_t len;
        int valid;

        if (argc != 2)
                usage();
                /* NOTREACHED */


        if (strchr(argv[1], ':')) {
                /* IPv6 */
                in = &in6;
                addr = addr6;
                af = AF_INET6;
                len = INET6_ADDRSTRLEN;
        } else {
                /* IPv4 */
                in = &in4;
                addr = addr4;
                af = AF_INET;
                len = INET_ADDRSTRLEN;
        }

        valid = inet_pton(af, argv[1], in);

        switch (valid) {
        case 1:         /* ok, pretty print */
                if (!inet_ntop(af, in, addr, len))
                        addr = strerror(errno);
                break;
        case 0:         /* not ok, just echo */
                addr = argv[1];
                break;
        default:        /* error */
                addr = strerror(errno);
                break;
        }

        printf("%svalid IPv%d address: %s\n",
                valid ? "" : "in",
                af == AF_INET ? 4 : 6,
                addr);

        return 0;
}