text: /*
   *
   * IP-address/hostname to country converter.
   *
   * Problem; you want to know where IP a.b.c.d is located.
   *
   * Use hns_gethostbyname ("d.c.b.a.zz.countries.nerd.dk")
   * and get the CNAME (host->h_name). Result will be:
   *   CNAME = zz<CC>.countries.nerd.dk with address 127.0.x.y (ver 1) or
   *   CNAME = <a.b.c.d>.zz.countries.nerd.dk with address 127.0.x.y (ver 2)
   *
   * The 2 letter country code is in <CC> and the ISO-3166 country
   * number is in x.y (number = x*256 + y). Version 2 of the protocol is missing
   * the <CC> number.
   *
   * Ref: http://countries.nerd.dk/more.html
   *
   * Written by G. Vanem <gvanem@yahoo.no> 2006, 2007
   *
   * NB! This program may not be big-endian aware.
   *
   * Permission to use, copy, modify, and distribute this
   * software and its documentation for any purpose and without
   * fee is hereby granted, provided that the above copyright
   * notice appear in all copies and that both that copyright
   * notice and this permission notice appear in supporting
   * documentation, and that the name of M.I.T. not be used in
   * advertising or publicity pertaining to distribution of the
   * software without specific, written prior permission.
   * M.I.T. makes no representations about the suitability of
   * this software for any purpose.  It is provided "as is"
   * without express or implied warranty.
   */
  
  #include "hns_setup.h"
  
  #ifdef HAVE_STRINGS_H
  #include <strings.h>
  #endif
  
  #if defined(WIN32) && !defined(WATT32)
    #include <winsock.h>
  #else
    #include <arpa/inet.h>
    #include <netinet/in.h>
    #include <netdb.h>
  #endif
  
  #include "hns.h"
  #include "hns_getopt.h"
  #include "hns_nowarn.h"
  
  #ifndef HAVE_STRDUP
  #  include "hns_strdup.h"
  #  define strdup(ptr) hns_strdup(ptr)
  #endif
  
  #ifndef HAVE_STRCASECMP
  #  include "hns_strcasecmp.h"
  #  define strcasecmp(p1,p2) hns_strcasecmp(p1,p2)
  #endif
  
  #ifndef HAVE_STRNCASECMP
  #  include "hns_strcasecmp.h"
  #  define strncasecmp(p1,p2,n) hns_strncasecmp(p1,p2,n)
  #endif
  
  #ifndef INADDR_NONE
  #define INADDR_NONE 0xffffffff
  #endif
  
  static const char *usage      = "hcountry [-vh?] {host|addr} ...\n";
  static const char  nerd_fmt[] = "%u.%u.%u.%u.zz.countries.nerd.dk";
  static const char *nerd_ver1  = nerd_fmt + 14;  /* .countries.nerd.dk */
  static const char *nerd_ver2  = nerd_fmt + 11;  /* .zz.countries.nerd.dk */
  static int         verbose    = 0;
  
  #define TRACE(fmt) do {               \
                       if (verbose > 0) \
                         printf fmt ;   \
                     } WHILE_FALSE
  
  static void wait_hns(hns_channel channel);
  static void callback(void *arg, int status, int timeouts, struct hostent *host);
  static void callback2(void *arg, int status, int timeouts, struct hostent *host);
  static void find_country_from_cname(const char *cname, struct in_addr addr);
  
  static void Abort(const char *fmt, ...)
  {
    va_list args;
    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);
    exit(1);
  }
  
  int main(int argc, char **argv)
  {
    hns_channel channel;
    int    ch, status;
  
  #if defined(WIN32) && !defined(WATT32)
    WORD wVersionRequested = MAKEWORD(USE_WINSOCK,USE_WINSOCK);
    WSADATA wsaData;
    WSAStartup(wVersionRequested, &wsaData);
  #endif
  
    status = hns_library_init(HNS_LIB_INIT_ALL);
    if (status != HNS_SUCCESS)
      {
        fprintf(stderr, "hns_library_init: %s\n", hns_strerror(status));
        return 1;
      }
  
    while ((ch = hns_getopt(argc, argv, "dvh?")) != -1)
      switch (ch)
        {
        case 'd':
  #ifdef WATT32
          dbug_init();
  #endif
          break;
        case 'v':
          verbose++;
          break;
        case 'h':
        case '?':
        default:
          Abort(usage);
        }
  
    argc -= optind;
    argv += optind;
    if (argc < 1)
       Abort(usage);
  
    status = hns_init(&channel);
    if (status != HNS_SUCCESS)
      {
        fprintf(stderr, "hns_init: %s\n", hns_strerror(status));
        return 1;
      }
  
    /* Initiate the queries, one per command-line argument. */
    for ( ; *argv; argv++)
      {
        struct in_addr addr;
        char buf[100];
  
        /* If this fails, assume '*argv' is a host-name that
         * must be resolved first
         */
        if (hns_inet_pton(AF_INET, *argv, &addr) != 1)
          {
            hns_gethostbyname(channel, *argv, AF_INET, callback2, &addr);
            wait_hns(channel);
            if (addr.s_addr == INADDR_NONE)
              {
                printf("Failed to lookup %s\n", *argv);
                continue;
              }
          }
  
        sprintf(buf, nerd_fmt,
                (unsigned int)(addr.s_addr >> 24),
                (unsigned int)((addr.s_addr >> 16) & 255),
                (unsigned int)((addr.s_addr >> 8) & 255),
                (unsigned int)(addr.s_addr & 255));
        TRACE(("Looking up %s...", buf));
        fflush(stdout);
        hns_gethostbyname(channel, buf, AF_INET, callback, buf);
      }
  
    wait_hns(channel);
    hns_destroy(channel);
  
    hns_library_cleanup();
  
  #if defined(WIN32) && !defined(WATT32)
    WSACleanup();
  #endif
  
    return 0;
  }
  
  /*
   * Wait for the queries to complete.
   */
  static void wait_hns(hns_channel channel)
  {
    for (;;)
      {
        struct timeval *tvp, tv;
        fd_set read_fds, write_fds;
        int nfds;
  
        FD_ZERO(&read_fds);
        FD_ZERO(&write_fds);
        nfds = hns_fds(channel, &read_fds, &write_fds);
        if (nfds == 0)
          break;
        tvp = hns_timeout(channel, NULL, &tv);
        nfds = select(nfds, &read_fds, &write_fds, NULL, tvp);
        if (nfds < 0)
          continue;
        hns_process(channel, &read_fds, &write_fds);
      }
  }
  
  /*
   * This is the callback used when we have the IP-address of interest.
   * Extract the CNAME and figure out the country-code from it.
   */
  static void callback(void *arg, int status, int timeouts, struct hostent *host)
  {
    const char *name = (const char*)arg;
    const char *cname;
    char buf[20];
  
    (void)timeouts;
  
    if (!host || status != HNS_SUCCESS)
      {
        printf("Failed to lookup %s: %s\n", name, hns_strerror(status));
        return;
      }
  
    TRACE(("\nFound address %s, name %s\n",
           hns_inet_ntop(AF_INET,(const char*)host->h_addr,buf,sizeof(buf)),
           host->h_name));
  
    cname = host->h_name;  /* CNAME gets put here */
    if (!cname)
      printf("Failed to get CNAME for %s\n", name);
    else
      find_country_from_cname(cname, *(struct in_addr*)host->h_addr);
  }
  
  /*
   * This is the callback used to obtain the IP-address of the host of interest.
   */
  static void callback2(void *arg, int status, int timeouts, struct hostent *host)
  {
    struct in_addr *addr = (struct in_addr*) arg;
  
    (void)timeouts;
    if (!host || status != HNS_SUCCESS)
      memset(addr, INADDR_NONE, sizeof(*addr));
    else
      memcpy(addr, host->h_addr, sizeof(*addr));
  }
  
  struct search_list {
         int         country_number; /* ISO-3166 country number */
         char        short_name[3];  /* A2 short country code */
         const char *long_name;      /* normal country name */
       };
  
  static const struct search_list *list_lookup(int number, const struct search_list *list, int num)
  {
    while (num > 0 && list->long_name)
      {
        if (list->country_number == number)
          return (list);
        num--;
        list++;
      }
    return (NULL);
  }
  
  /*
   * Ref: ftp://ftp.ripe.net/iso3166-countrycodes.txt
   */
  static const struct search_list country_list[] = {
         {   4, "af", "Afghanistan"                          },
         { 248, "ax", "Åland Island"                         },
         {   8, "al", "Albania"                              },
         {  12, "dz", "Algeria"                              },
         {  16, "as", "American Samoa"                       },
         {  20, "ad", "Andorra"                              },
         {  24, "ao", "Angola"                               },
         { 660, "ai", "Anguilla"                             },
         {  10, "aq", "Antarctica"                           },
         {  28, "ag", "Antigua & Barbuda"                    },
         {  32, "ar", "Argentina"                            },
         {  51, "am", "Armenia"                              },
         { 533, "aw", "Aruba"                                },
         {  36, "au", "Australia"                            },
         {  40, "at", "Austria"                              },
         {  31, "az", "Azerbaijan"                           },
         {  44, "bs", "Bahamas"                              },
         {  48, "bh", "Bahrain"                              },
         {  50, "bd", "Bangladesh"                           },
         {  52, "bb", "Barbados"                             },
         { 112, "by", "Belarus"                              },
         {  56, "be", "Belgium"                              },
         {  84, "bz", "Belize"                               },
         { 204, "bj", "Benin"                                },
         {  60, "bm", "Bermuda"                              },
         {  64, "bt", "Bhutan"                               },
         {  68, "bo", "Bolivia"                              },
         {  70, "ba", "Bosnia & Herzegowina"                 },
         {  72, "bw", "Botswana"                             },
         {  74, "bv", "Bouvet Island"                        },
         {  76, "br", "Brazil"                               },
         {  86, "io", "British Indian Ocean Territory"       },
         {  96, "bn", "Brunei Darussalam"                    },
         { 100, "bg", "Bulgaria"                             },
         { 854, "bf", "Burkina Faso"                         },
         { 108, "bi", "Burundi"                              },
         { 116, "kh", "Cambodia"                             },
         { 120, "cm", "Cameroon"                             },
         { 124, "ca", "Canada"                               },
         { 132, "cv", "Cape Verde"                           },
         { 136, "ky", "Cayman Islands"                       },
         { 140, "cf", "Central African Republic"             },
         { 148, "td", "Chad"                                 },
         { 152, "cl", "Chile"                                },
         { 156, "cn", "China"                                },
         { 162, "cx", "Christmas Island"                     },
         { 166, "cc", "Cocos Islands"                        },
         { 170, "co", "Colombia"                             },
         { 174, "km", "Comoros"                              },
         { 178, "cg", "Congo"                                },
         { 180, "cd", "Congo"                                },
         { 184, "ck", "Cook Islands"                         },
         { 188, "cr", "Costa Rica"                           },
         { 384, "ci", "Cote d'Ivoire"                        },
         { 191, "hr", "Croatia"                              },
         { 192, "cu", "Cuba"                                 },
         { 196, "cy", "Cyprus"                               },
         { 203, "cz", "Czech Republic"                       },
         { 208, "dk", "Denmark"                              },
         { 262, "dj", "Djibouti"                             },
         { 212, "dm", "Dominica"                             },
         { 214, "do", "Dominican Republic"                   },
         { 218, "ec", "Ecuador"                              },
         { 818, "eg", "Egypt"                                },
         { 222, "sv", "El Salvador"                          },
         { 226, "gq", "Equatorial Guinea"                    },
         { 232, "er", "Eritrea"                              },
         { 233, "ee", "Estonia"                              },
         { 231, "et", "Ethiopia"                             },
         { 238, "fk", "Falkland Islands"                     },
         { 234, "fo", "Faroe Islands"                        },
         { 242, "fj", "Fiji"                                 },
         { 246, "fi", "Finland"                              },
         { 250, "fr", "France"                               },
         { 249, "fx", "France, Metropolitan"                 },
         { 254, "gf", "French Guiana"                        },
         { 258, "pf", "French Polynesia"                     },
         { 260, "tf", "French Southern Territories"          },
         { 266, "ga", "Gabon"                                },
         { 270, "gm", "Gambia"                               },
         { 268, "ge", "Georgia"                              },
         { 276, "de", "Germany"                              },
         { 288, "gh", "Ghana"                                },
         { 292, "gi", "Gibraltar"                            },
         { 300, "gr", "Greece"                               },
         { 304, "gl", "Greenland"                            },
         { 308, "gd", "Grenada"                              },
         { 312, "gp", "Guadeloupe"                           },
         { 316, "gu", "Guam"                                 },
         { 320, "gt", "Guatemala"                            },
         { 324, "gn", "Guinea"                               },
         { 624, "gw", "Guinea-Bissau"                        },
         { 328, "gy", "Guyana"                               },
         { 332, "ht", "Haiti"                                },
         { 334, "hm", "Heard & Mc Donald Islands"            },
         { 336, "va", "Vatican City"                         },
         { 340, "hn", "Honduras"                             },
         { 344, "hk", "Hong kong"                            },
         { 348, "hu", "Hungary"                              },
         { 352, "is", "Iceland"                              },
         { 356, "in", "India"                                },
         { 360, "id", "Indonesia"                            },
         { 364, "ir", "Iran"                                 },
         { 368, "iq", "Iraq"                                 },
         { 372, "ie", "Ireland"                              },
         { 376, "il", "Israel"                               },
         { 380, "it", "Italy"                                },
         { 388, "jm", "Jamaica"                              },
         { 392, "jp", "Japan"                                },
         { 400, "jo", "Jordan"                               },
         { 398, "kz", "Kazakhstan"                           },
         { 404, "ke", "Kenya"                                },
         { 296, "ki", "Kiribati"                             },
         { 408, "kp", "Korea (north)"                        },
         { 410, "kr", "Korea (south)"                        },
         { 414, "kw", "Kuwait"                               },
         { 417, "kg", "Kyrgyzstan"                           },
         { 418, "la", "Laos"                                 },
         { 428, "lv", "Latvia"                               },
         { 422, "lb", "Lebanon"                              },
         { 426, "ls", "Lesotho"                              },
         { 430, "lr", "Liberia"                              },
         { 434, "ly", "Libya"                                },
         { 438, "li", "Liechtenstein"                        },
         { 440, "lt", "Lithuania"                            },
         { 442, "lu", "Luxembourg"                           },
         { 446, "mo", "Macao"                                },
         { 807, "mk", "Macedonia"                            },
         { 450, "mg", "Madagascar"                           },
         { 454, "mw", "Malawi"                               },
         { 458, "my", "Malaysia"                             },
         { 462, "mv", "Maldives"                             },
         { 466, "ml", "Mali"                                 },
         { 470, "mt", "Malta"                                },
         { 584, "mh", "Marshall Islands"                     },
         { 474, "mq", "Martinique"                           },
         { 478, "mr", "Mauritania"                           },
         { 480, "mu", "Mauritius"                            },
         { 175, "yt", "Mayotte"                              },
         { 484, "mx", "Mexico"                               },
         { 583, "fm", "Micronesia"                           },
         { 498, "md", "Moldova"                              },
         { 492, "mc", "Monaco"                               },
         { 496, "mn", "Mongolia"                             },
         { 500, "ms", "Montserrat"                           },
         { 504, "ma", "Morocco"                              },
         { 508, "mz", "Mozambique"                           },
         { 104, "mm", "Myanmar"                              },
         { 516, "na", "Namibia"                              },
         { 520, "nr", "Nauru"                                },
         { 524, "np", "Nepal"                                },
         { 528, "nl", "Netherlands"                          },
         { 530, "an", "Netherlands Antilles"                 },
         { 540, "nc", "New Caledonia"                        },
         { 554, "nz", "New Zealand"                          },
         { 558, "ni", "Nicaragua"                            },
         { 562, "ne", "Niger"                                },
         { 566, "ng", "Nigeria"                              },
         { 570, "nu", "Niue"                                 },
         { 574, "nf", "Norfolk Island"                       },
         { 580, "mp", "Northern Mariana Islands"             },
         { 578, "no", "Norway"                               },
         { 512, "om", "Oman"                                 },
         { 586, "pk", "Pakistan"                             },
         { 585, "pw", "Palau"                                },
         { 275, "ps", "Palestinian Territory"                },
         { 591, "pa", "Panama"                               },
         { 598, "pg", "Papua New Guinea"                     },
         { 600, "py", "Paraguay"                             },
         { 604, "pe", "Peru"                                 },
         { 608, "ph", "Philippines"                          },
         { 612, "pn", "Pitcairn"                             },
         { 616, "pl", "Poland"                               },
         { 620, "pt", "Portugal"                             },
         { 630, "pr", "Puerto Rico"                          },
         { 634, "qa", "Qatar"                                },
         { 638, "re", "Reunion"                              },
         { 642, "ro", "Romania"                              },
         { 643, "ru", "Russia"                               },
         { 646, "rw", "Rwanda"                               },
         { 659, "kn", "Saint Kitts & Nevis"                  },
         { 662, "lc", "Saint Lucia"                          },
         { 670, "vc", "Saint Vincent"                        },
         { 882, "ws", "Samoa"                                },
         { 674, "sm", "San Marino"                           },
         { 678, "st", "Sao Tome & Principe"                  },
         { 682, "sa", "Saudi Arabia"                         },
         { 686, "sn", "Senegal"                              },
         { 891, "cs", "Serbia and Montenegro"                },
         { 690, "sc", "Seychelles"                           },
         { 694, "sl", "Sierra Leone"                         },
         { 702, "sg", "Singapore"                            },
         { 703, "sk", "Slovakia"                             },
         { 705, "si", "Slovenia"                             },
         {  90, "sb", "Solomon Islands"                      },
         { 706, "so", "Somalia"                              },
         { 710, "za", "South Africa"                         },
         { 239, "gs", "South Georgia"                        },
         { 724, "es", "Spain"                                },
         { 144, "lk", "Sri Lanka"                            },
         { 654, "sh", "St. Helena"                           },
         { 666, "pm", "St. Pierre & Miquelon"                },
         { 736, "sd", "Sudan"                                },
         { 740, "sr", "Suriname"                             },
         { 744, "sj", "Svalbard & Jan Mayen Islands"         },
         { 748, "sz", "Swaziland"                            },
         { 752, "se", "Sweden"                               },
         { 756, "ch", "Switzerland"                          },
         { 760, "sy", "Syrian Arab Republic"                 },
         { 626, "tl", "Timor-Leste"                          },
         { 158, "tw", "Taiwan"                               },
         { 762, "tj", "Tajikistan"                           },
         { 834, "tz", "Tanzania"                             },
         { 764, "th", "Thailand"                             },
         { 768, "tg", "Togo"                                 },
         { 772, "tk", "Tokelau"                              },
         { 776, "to", "Tonga"                                },
         { 780, "tt", "Trinidad & Tobago"                    },
         { 788, "tn", "Tunisia"                              },
         { 792, "tr", "Turkey"                               },
         { 795, "tm", "Turkmenistan"                         },
         { 796, "tc", "Turks & Caicos Islands"               },
         { 798, "tv", "Tuvalu"                               },
         { 800, "ug", "Uganda"                               },
         { 804, "ua", "Ukraine"                              },
         { 784, "ae", "United Arab Emirates"                 },
         { 826, "gb", "United Kingdom"                       },
         { 840, "us", "United States"                        },
         { 581, "um", "United States Minor Outlying Islands" },
         { 858, "uy", "Uruguay"                              },
         { 860, "uz", "Uzbekistan"                           },
         { 548, "vu", "Vanuatu"                              },
         { 862, "ve", "Venezuela"                            },
         { 704, "vn", "Vietnam"                              },
         {  92, "vg", "Virgin Islands (British)"             },
         { 850, "vi", "Virgin Islands (US)"                  },
         { 876, "wf", "Wallis & Futuna Islands"              },
         { 732, "eh", "Western Sahara"                       },
         { 887, "ye", "Yemen"                                },
         { 894, "zm", "Zambia"                               },
         { 716, "zw", "Zimbabwe"                             }
       };
  
  /*
   * Check if start of 'str' is simply an IPv4 address.
   */
  #define BYTE_OK(x) ((x) >= 0 && (x) <= 255)
  
  static int is_addr(char *str, char **end)
  {
    int a0, a1, a2, a3, num, rc = 0, length = 0;
  
    num = sscanf(str,"%3d.%3d.%3d.%3d%n",&a0,&a1,&a2,&a3,&length);
    if( (num == 4) &&
        BYTE_OK(a0) && BYTE_OK(a1) && BYTE_OK(a2) && BYTE_OK(a3) &&
        length >= (3+4))
      {
        rc = 1;
        *end = str + length;
      }
    return rc;
  }
  
  /*
   * Find the country-code and name from the CNAME. E.g.:
   *   version 1: CNAME = zzno.countries.nerd.dk with address 127.0.2.66
   *              yields ccode_A" = "no" and cnumber 578 (2.66).
   *   version 2: CNAME = <a.b.c.d>.zz.countries.nerd.dk with address 127.0.2.66
   *              yields cnumber 578 (2.66). ccode_A is "";
   */
  static void find_country_from_cname(const char *cname, struct in_addr addr)
  {
    const struct search_list *country;
    char  ccode_A2[3], *ccopy, *dot_4;
    int   cnumber, z0, z1, ver_1, ver_2;
    unsigned long ip;
  
    ip = ntohl(addr.s_addr);
    z0 = TOLOWER(cname[0]);
    z1 = TOLOWER(cname[1]);
    ccopy = strdup(cname);
    dot_4 = NULL;
  
    ver_1 = (z0 == 'z' && z1 == 'z' && !strcasecmp(cname+4,nerd_ver1));
    ver_2 = (is_addr(ccopy,&dot_4) && !strcasecmp(dot_4,nerd_ver2));
  
    if (ver_1)
      {
        const char *dot = strchr(cname, '.');
        if (dot != cname+4)
          {
            printf("Unexpected CNAME %s (ver_1)\n", cname);
            free(ccopy);
            return;
          }
      }
    else if (ver_2)
      {
        z0 = TOLOWER(dot_4[1]);
        z1 = TOLOWER(dot_4[2]);
        if (z0 != 'z' && z1 != 'z')
          {
            printf("Unexpected CNAME %s (ver_2)\n", cname);
            free(ccopy);
            return;
          }
      }
    else
      {
        printf("Unexpected CNAME %s (ver?)\n", cname);
        free(ccopy);
        return;
      }
  
    if (ver_1)
      {
        ccode_A2[0] = (char)TOLOWER(cname[2]);
        ccode_A2[1] = (char)TOLOWER(cname[3]);
        ccode_A2[2] = '\0';
      }
    else
      ccode_A2[0] = '\0';
  
    cnumber = ip & 0xFFFF;
  
    TRACE(("Found country-code `%s', number %d\n",
           ver_1 ? ccode_A2 : "<n/a>", cnumber));
  
    country = list_lookup(cnumber, country_list,
                          sizeof(country_list) / sizeof(country_list[0]));
    if (!country)
      printf("Name for country-number %d not found.\n", cnumber);
    else
      {
        if (ver_1)
          {
            if ((country->short_name[0] != ccode_A2[0]) ||
                (country->short_name[1] != ccode_A2[1]) ||
                (country->short_name[2] != ccode_A2[2]))
              printf("short-name mismatch; %s vs %s\n",
                     country->short_name, ccode_A2);
          }
        printf("%s (%s), number %d.\n",
               country->long_name, country->short_name, cnumber);
      }
    free(ccopy);
  }
  