Another sample application that returns country-code and

name from an IPv4-address or host-name. Using the service of
countries.nerd.dk.

1 files changed, 584 insertions, 0 deletions

diff --git a/acountry.c b/acountry.c
new file mode 100644
index 0000000..e2c3255
--- /dev/null
+++ b/acountry.c
@@ -0,0 +1,584 @@
+/*
+ * $Id$
+ *
+ * IP-address/hostname to country converter.
+ *
+ * Problem; you want to know where IP a.b.c.d is located.
+ *
+ * Use ares_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 in <CC> and the ISO-3166 country
+ * number 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@broadpark.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 "setup.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <ctype.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#if defined(WIN32)
+  #include <winsock.h>
+#else
+  #include <arpa/inet.h>
+  #include <netinet/in.h>
+  #include <netdb.h>
+#endif
+
+#include "ares.h"
+#include "ares_getopt.h"
+#include "inet_net_pton.h"
+#include "inet_ntop.h"
+
+static const char *usage      = "acountry [-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;
+static const char *nerd_ver2  = nerd_fmt + 11;
+static int         verbose    = 0;
+
+#define TRACE(fmt) do {               \
+                     if (verbose > 0) \
+                       printf fmt ;   \
+                   } while (0)
+
+static void wait_ares(ares_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)
+{
+  ares_channel channel;
+  int    ch, status;
+
+#ifdef WIN32
+  WORD wVersionRequested = MAKEWORD(USE_WINSOCK,USE_WINSOCK);
+  WSADATA wsaData;
+  WSAStartup(wVersionRequested, &wsaData);
+#endif
+
+  while ((ch = ares_getopt(argc, argv, "vh?")) != -1)
+    switch (ch)
+      {
+      case 'v':
+        verbose++;
+        break;
+      case 'h':
+      case '?':
+      default:
+        Abort(usage);
+      }
+
+  argc -= optind;
+  argv += optind;
+  if (argc < 1)
+     Abort(usage);
+
+  status = ares_init(&channel);
+  if (status != ARES_SUCCESS)
+    {
+      fprintf(stderr, "ares_init: %s\n", ares_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 (ares_inet_pton(AF_INET, *argv, &addr) != 1)
+        {
+          ares_gethostbyname(channel, *argv, AF_INET, callback2, &addr);
+          wait_ares(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);
+      ares_gethostbyname(channel, buf, AF_INET, callback, buf);
+    }
+
+  wait_ares(channel);
+  ares_destroy(channel);
+
+#ifdef WIN32
+  WSACleanup();
+#endif
+
+  return 0;
+}
+
+/*
+ * Wait for the queries to complete.
+ */
+static void wait_ares(ares_channel channel)
+{
+  while (1)
+    {
+      struct timeval *tvp, tv;
+      fd_set read_fds, write_fds;
+      int nfds;
+
+      FD_ZERO(&read_fds);
+      FD_ZERO(&write_fds);
+      nfds = ares_fds(channel, &read_fds, &write_fds);
+      if (nfds == 0)
+        break;
+      tvp = ares_timeout(channel, NULL, &tv);
+      select(nfds, &read_fds, &write_fds, NULL, tvp);
+      ares_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 != ARES_SUCCESS)
+    {
+      printf("Failed to lookup %s: %s\n", name, ares_strerror(status));
+      return;
+    }
+
+  TRACE(("\nFound address %s, name %s\n",
+         ares_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 != ARES_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 */
+     };
+
+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;
+
+  if ((num = sscanf(str,"%3d.%3d.%3d.%3d%n",&a0,&a1,&a2,&a3,&length)) == 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;
+  u_long ip;
+
+  ip = ntohl(addr.s_addr);
+  z0 = tolower(cname[0]);
+  z1 = tolower(cname[1]);
+  ccopy = strdup(cname);
+
+  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 ((z0 != 'z' && z1 != 'z') || dot != cname+4)
+        {
+          printf("Unexpected CNAME %s (ver_1)\n", cname);
+          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);
+          return;
+        }
+    }
+  else
+    {
+      printf("Unexpected CNAME %s (ver?)\n", cname);
+      return;
+    }
+
+  if (ver_1)
+    {
+      ccode_A2[0] = tolower(cname[2]);
+      ccode_A2[1] = 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 && *(unsigned short*)&country->short_name != *(unsigned*)&ccode_A2)
+        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);
+}
+