listati/mygetaddr.c

   1     /* remaining argument check */
   2     if ((argc - optind) != 2) {
   3         printf("Wrong number of arguments %d\n", argc - optind);
   4         usage();
   5     }
   6     /* main body */
   7     ret = getaddrinfo(argv[optind], argv[optind+1], &hint, &res);
   8     if (ret != 0) {
   9         printf("Resolution error %s\n", gai_strerror(ret));
  10         exit(1);
  11     }
  12     ptr = res;                                        /* init list pointer */
  13     printf("Canonical name %s\n", ptr->ai_canonname); /* print cname */
  14     while (ptr != NULL) {                             /* loop on list */
  15         if (ptr->ai_family == AF_INET) {              /* if IPv4 */
  16             printf("IPv4 address: \n");
  17             addr = (struct sockaddr_in *) ptr->ai_addr;     /* address */
  18             port = ntohs(addr->sin_port);                   /* port */
  19             string = inet_ntop(addr->sin_family, &addr->sin_addr,
  20                                buffer, sizeof(buffer));
  21         } else if (ptr->ai_family == AF_INET6) {      /* if IPv6 */
  22             printf("IPv6 address: \n");
  23             addr6 = (struct sockaddr_in6 *) ptr->ai_addr;   /* address */
  24             port = ntohs(addr6->sin6_port);                 /* port */
  25             string = inet_ntop(addr6->sin6_family, &addr6->sin6_addr,
  26                                buffer, sizeof(buffer));
  27         } else {                                      /* else is an error */
  28             printf("Address family error\n");
  29             exit(1);
  30         }
  31         printf("\tIndirizzo %s\n", string);
  32         printf("\tProtocollo %i\n", ptr->ai_protocol);
  33         printf("\tPorta %i\n", port);
  34         ptr = ptr->ai_next;
  35     }
  36     exit(0);