#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

static int usage()
{
  printf("usage: ./getaddrinfo [inet|inet6|all] port [host]\n");
  exit(EXIT_FAILURE);
}

int main(int argc, char *argv[])
{
  char *host, *type, *port;
  struct addrinfo hints, *res = 0;
  int ret;

  if (argc != 3 && argc != 4)
    usage();

  type = argv[1];
  port = argv[2];
  if (argc == 4)
    host = argv[3];
  else
    host = NULL;

  memset (&hints, 0, sizeof (hints));
  if (!strcmp("inet", type))
    hints.ai_family = AF_INET;
  else if (!strcmp("inet6", type))
    hints.ai_family = AF_INET6;
  else if (!strcmp("all", type))
    hints.ai_family = AF_UNSPEC;
  else
    usage();
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags    = AI_ADDRCONFIG | AI_PASSIVE;

  ret = getaddrinfo(host, port, &hints, &res);
  if (ret) {
    printf("getaddrinfo: %s", strerror(-ret));
    return EXIT_FAILURE;
  }

  {
    char host[64];
    char serv[64];

    ret = getnameinfo(res->ai_addr, res->ai_addrlen,
		      host, sizeof(host), serv, sizeof(serv),
		      NI_NUMERICHOST | NI_NUMERICSERV);
    printf("%s %s (%d)\n", host, serv, ret);
    ret = getnameinfo(res->ai_addr, res->ai_addrlen,
		      host, sizeof(host), serv, sizeof(serv),
		      0);
    printf("%s %s (%d)\n", host, serv, ret);
    puts("ok");
  }
  freeaddrinfo(res);
  return 0;
}