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libmaxminddb(3)                                                libmaxminddb(3)


NAME

       libmaxminddb - a library for working with MaxMind DB files


SYNOPSIS



           #include <maxminddb.h>

           int MMDB_open(
               const char *const filename,
               uint32_t flags,
               MMDB_s *const mmdb);
           void MMDB_close(MMDB_s *const mmdb);

           MMDB_lookup_result_s MMDB_lookup_string(
               MMDB_s *const mmdb,
               const char *const ipstr,
               int *const gai_error,
               int *const mmdb_error);
           MMDB_lookup_result_s MMDB_lookup_sockaddr(
               MMDB_s *const mmdb,
               const struct sockaddr *const
               sockaddr,
               int *const mmdb_error);

           int MMDB_get_value(
               MMDB_entry_s *const start,
               MMDB_entry_data_s *const entry_data,
               ...);
           int MMDB_vget_value(
               MMDB_entry_s *const start,
               MMDB_entry_data_s *const entry_data,
               va_list va_path);
           int MMDB_aget_value(
               MMDB_entry_s *const start,
               MMDB_entry_data_s *const entry_data,
               const char *const *const path);

           int MMDB_get_entry_data_list(
               MMDB_entry_s *start,
               MMDB_entry_data_list_s **const entry_data_list);
           void MMDB_free_entry_data_list(
               MMDB_entry_data_list_s *const entry_data_list);
           int MMDB_get_metadata_as_entry_data_list(
               MMDB_s *const mmdb,
               MMDB_entry_data_list_s **const entry_data_list);
           int MMDB_dump_entry_data_list(
               FILE *const stream,
               MMDB_entry_data_list_s *const entry_data_list,
               int indent);

           int MMDB_read_node(
               MMDB_s *const mmdb,
               uint32_t node_number,
               MMDB_search_node_s *const node);

           const char *MMDB_lib_version(void);
           const char *MMDB_strerror(int error_code);

           typedef struct MMDB_lookup_result_s {
               bool found_entry;
               MMDB_entry_s entry;
               uint16_t netmask;
           } MMDB_lookup_result_s;

           typedef struct MMDB_entry_data_s {
               bool has_data;
               union {
                   uint32_t pointer;
                   const char *utf8_string;
                   double double_value;
                   const uint8_t *bytes;
                   uint16_t uint16;
                   uint32_t uint32;
                   int32_t int32;
                   uint64_t uint64;
                   {mmdb_uint128_t or uint8_t[16]} uint128;
                   bool boolean;
                   float float_value;
               };
               ...
               uint32_t data_size;
               uint32_t type;
           } MMDB_entry_data_s;

           typedef struct MMDB_entry_data_list_s {
               MMDB_entry_data_s entry_data;
               struct MMDB_entry_data_list_s *next;
           } MMDB_entry_data_list_s;



DESCRIPTION

       The libmaxminddb library provides functions for working MaxMind DB
       files.  See https://maxmind.github.io/MaxMind-DB/ for the MaxMind DB
       format specification.  The database and results are all represented by
       different data structures.  Databases are opened by calling
       MMDB_open().  You can look up IP addresses as a string with
       MMDB_lookup_string() or as a pointer to a sockaddr structure with
       MMDB_lookup_sockaddr().

       If the lookup finds the IP address in the database, it returns a
       MMDB_lookup_result_s structure.  If that structure indicates that the
       database has data for the IP, there are a number of functions that can
       be used to fetch that data.  These include MMDB_get_value() and
       MMDB_get_entry_data_list().  See the function documentation below for
       more details.

       When you are done with the database handle you should call
       MMDB_close().

       All publicly visible functions, structures, and macros begin with
       "MMDB_".


DATA STRUCTURES

       All data structures exported by this library's maxminddb.h header are
       typedef'd in the form typedef struct foo_s { ... } foo_s so you can
       refer to them without the struct prefix.

       This library provides the following data structures:

   MMDB_s
       This is the handle for a MaxMind DB file.  We only document some of
       this structure's fields intended for public use.  All other fields are
       subject to change and are intended only for internal use.



           typedef struct MMDB_s {
               uint32_t flags;
               const char *filename;
               ...
               MMDB_metadata_s metadata;
           } MMDB_s;


       o uint32_t flags - the flags this database was opened with.  See the
         MMDB_open() documentation for more details.

       o const char *filename - the name of the file which was opened, as
         passed to MMDB_open().

       o MMDB_metadata_s metadata - the metadata for the database.

   MMDB_metadata_s and MMDB_description_s
       This structure can be retrieved from the MMDB_s structure.  It contains
       the metadata read from the database file.  Note that you may find it
       more convenient to access this metadata by calling
       MMDB_get_metadata_as_entry_data_list() instead.



           typedef struct MMDB_metadata_s {
               uint32_t node_count;
               uint16_t record_size;
               uint16_t ip_version;
               const char *database_type;
               struct {
                   size_t count;
                   const char **names;
               } languages;
               uint16_t binary_format_major_version;
               uint16_t binary_format_minor_version;
               uint64_t build_epoch;
               struct {
                   size_t count;
                   MMDB_description_s **descriptions;
               } description;
           } MMDB_metadata_s;

           typedef struct MMDB_description_s {
               const char *language;
               const char *description;
           } MMDB_description_s;


       These structures should be mostly self-explanatory.

       The ip_version member should always be 4 or 6.  The
       binary_format_major_version should always be 2.

       There is no requirement that the database metadata include languages or
       descriptions, so the count for these parts of the metadata can be zero.
       All of the other MMDB_metadata_s fields should be populated.

   MMDB_lookup_result_s
       This structure is returned as the result of looking up an IP address.



           typedef struct MMDB_lookup_result_s {
               bool found_entry;
               MMDB_entry_s entry;
               uint16_t netmask;
           } MMDB_lookup_result_s;


       If the found_entry member is false then the other members of this
       structure do not contain meaningful values.  Always check that
       found_entry is true first.

       The entry member is used to look up the data associated with the IP
       address.

       The netmask member tells you what subnet the IP address belongs to in
       this database.  For example, if you look up the address 1.1.1.1 in an
       IPv4 database and the returned netmask is 16, then the address is part
       of the 1.1.0.0/16 subnet.

       If the database is an IPv6 database, the returned netmask is always an
       IPv6 prefix length (from 0-128), even if that database also contains
       IPv4 networks.  If you look up an IPv4 address and would like to turn
       the netmask into an IPv4 netmask value, you can simply subtract 96 from
       the value.

   MMDB_result_s
       You don't really need to dig around in this structure.  You'll get this
       from a MMDB_lookup_result_s structure and pass it to various functions.

   MMDB_entry_data_s
       This structure is used to return a single data section entry for an IP.
       These entries can in turn point to other entries, as is the case for
       things like maps and arrays.  Some members of this structure are not
       documented as they are only for internal use.



           typedef struct MMDB_entry_data_s {
               bool has_data;
               union {
                   uint32_t pointer;
                   const char *utf8_string;
                   double double_value;
                   const uint8_t *bytes;
                   uint16_t uint16;
                   uint32_t uint32;
                   int32_t int32;
                   uint64_t uint64;
                   {mmdb_uint128_t or uint8_t[16]} uint128;
                   bool boolean;
                   float float_value;
               };
               ...
               uint32_t data_size;
               uint32_t type;
           } MMDB_entry_data_s;


       The has_data member is true if data was found for a given lookup.  See
       MMDB_get_value() for more details.  If this member is false then none
       of the other values in the structure are meaningful.

       The union at the beginning of the structure defines the actual data.
       To determine which union member is populated you should look at the
       type member.  The pointer member of the union should never be populated
       in any data returned by the API.  Pointers should always be resolved
       internally.

       The data_size member is only relevant for utf8_string and bytes data.
       utf8_string is not null terminated and data_size must be used to
       determine its length.

       The type member can be compared to one of the MMDB_DATA_TYPE_* macros.

   128-bit Integers
       The handling of uint128 data depends on how your platform supports
       128-bit integers, if it does so at all.  With GCC 4.4 and 4.5 we can
       write unsigned int __attribute__ ((__mode__ (TI))).  With newer
       versions of GCC (4.6+) and clang (3.2+) we can simply write "unsigned
       __int128".

       In order to work around these differences, this library defines an
       mmdb_uint128_t type.  This type is defined in the maxminddb.h header so
       you can use it in your own code.

       With older compilers, we can't use an integer so we instead use a 16
       byte array of uint8_t values.  This is the raw data from the database.

       This library provides a public macro MMDB_UINT128_IS_BYTE_ARRAY macro.
       If this is true (1), then uint128 values are returned as a byte array,
       if it is false then they are returned as a mmdb_uint128_t integer.

   Data Type Macros
       This library provides a macro for every data type defined by the
       MaxMind DB spec.

       o MMDB_DATA_TYPE_UTF8_STRING

       o MMDB_DATA_TYPE_DOUBLE

       o MMDB_DATA_TYPE_BYTES

       o MMDB_DATA_TYPE_UINT16

       o MMDB_DATA_TYPE_UINT32

       o MMDB_DATA_TYPE_MAP

       o MMDB_DATA_TYPE_INT32

       o MMDB_DATA_TYPE_UINT64

       o MMDB_DATA_TYPE_UINT128

       o MMDB_DATA_TYPE_ARRAY

       o MMDB_DATA_TYPE_BOOLEAN

       o MMDB_DATA_TYPE_FLOAT

       There are also a few types that are for internal use only:

       o MMDB_DATA_TYPE_EXTENDED

       o MMDB_DATA_TYPE_POINTER

       o MMDB_DATA_TYPE_CONTAINER

       o MMDB_DATA_TYPE_END_MARKER

       If you see one of these in returned data then something has gone very
       wrong.  The database is damaged or was generated incorrectly or there
       is a bug in the libmaxminddb code.

   Pointer Values and MMDB_close()
       The utf8_string, bytes, and (maybe) the uint128 members of this
       structure are all pointers directly into the database's data section.
       This can either be a calloc'd or mmap'd block of memory.  In either
       case, these pointers will become invalid after MMDB_close() is called.

       If you need to refer to this data after that time you should copy the
       data with an appropriate function (strdup, memcpy, etc.).

   MMDB_entry_data_list_s
       This structure encapsulates a linked list of MMDB_entry_data_s
       structures.



           typedef struct MMDB_entry_data_list_s {
               MMDB_entry_data_s entry_data;
               struct MMDB_entry_data_list_s *next;
           } MMDB_entry_data_list_s;


       This structure lets you look at entire map or array data entry by
       iterating over the linked list.

   MMDB_search_node_s
       This structure encapsulates the two records in a search node.  This is
       really only useful if you want to write code that iterates over the
       entire search tree as opposed to looking up a specific IP address.



           typedef struct MMDB_search_node_s {
               uint64_t left_record;
               uint64_t right_record;
               uint8_t left_record_type;
               uint8_t right_record_type;
               MMDB_entry_s left_record_entry;
               MMDB_entry_s right_record_entry;
           } MMDB_search_node_s;


       The two record types will take one of the following values:

       o MMDB_RECORD_TYPE_SEARCH_NODE - The record points to the next search
         node.

       o MMDB_RECORD_TYPE_EMPTY - The record is a placeholder that indicates
         there is no data for the IP address.  The search should end here.

       o MMDB_RECORD_TYPE_DATA - The record is for data in the data section of
         the database.  Use the entry for the record when looking up the data
         for the record.

       o MMDB_RECORD_TYPE_INVALID - The record is invalid.  Either an invalid
         node was looked up or the database is corrupt.

       The MMDB_entry_s for the record is only valid if the type is
       MMDB_RECORD_TYPE_DATA.  Attempts to use an entry for other record types
       will result in an error or invalid data.


STATUS CODES

       This library returns (or populates) status codes for many functions.
       These status codes are:

       o MMDB_SUCCESS - everything worked

       o MMDB_FILE_OPEN_ERROR - there was an error trying to open the MaxMind
         DB file.

       o MMDB_IO_ERROR - an IO operation failed.  Check errno for more
         details.

       o MMDB_CORRUPT_SEARCH_TREE_ERROR - looking up an IP address in the
         search tree gave us an impossible result.  The database is damaged or
         was generated incorrectly or there is a bug in the libmaxminddb code.

       o MMDB_INVALID_METADATA_ERROR - something in the database is wrong.
         This includes missing metadata keys as well as impossible values
         (like an ip_version of 7).

       o MMDB_UNKNOWN_DATABASE_FORMAT_ERROR - The database metadata indicates
         that it's major version is not 2.  This library can only handle major
         version 2.

       o MMDB_OUT_OF_MEMORY_ERROR - a memory allocation call (malloc, etc.)
         failed.

       o MMDB_INVALID_DATA_ERROR - an entry in the data section contains
         invalid data.  For example, a uint16 field is claiming to be more
         than 2 bytes long.  The database is probably damaged or was generated
         incorrectly.

       o MMDB_INVALID_LOOKUP_PATH_ERROR - The lookup path passed to
         MMDB_get_value, MMDB_vget_value, or MMDB_aget_value contains an array
         offset that is larger than LONG_MAX or smaller than LONG_MIN.

       o MMDB_LOOKUP_PATH_DOES_NOT_MATCH_DATA_ERROR - The lookup path passed
         to MMDB_get_value,MMDB_vget_value, or MMDB_aget_value does not match
         the data structure for the entry.  There are number of reasons this
         can happen.  The lookup path could include a key not in a map.  The
         lookup path could include an array index larger than an array or
         smaller than the minimum offset from the end of an array.  It can
         also happen when the path expects to find a map or array where none
         exist.

       All status codes should be treated as int values.

   MMDB_strerror()


           const char *MMDB_strerror(int error_code)


       This function takes a status code and returns an English string
       explaining the status.


FUNCTIONS

       This library provides the following exported functions:

   MMDB_open()


           int MMDB_open(
               const char *const filename,
               uint32_t flags,
               MMDB_s *const mmdb);


       This function opens a handle to a MaxMind DB file.  Its return value is
       a status code as defined above.  Always check this call's return value.



           MMDB_s mmdb;
           int status =
               MMDB_open("/path/to/file.mmdb", MMDB_MODE_MMAP, &mmdb);
           if (MMDB_SUCCESS != status) { ... }
           ...
           MMDB_close(&mmdb);


       filename must be encoded as UTF-8 on Windows.

       The MMDB_s structure you pass in can be on the stack or allocated from
       the heap.  However, if the open is successful it will contain heap-
       allocated data, so you need to close it with MMDB_close().  If the
       status returned is not MMDB_SUCCESS then this library makes sure that
       all allocated memory is freed before returning.

       The flags currently provided are:

       o MMDB_MODE_MMAP - open the database with mmap().

       Passing in other values for flags may yield unpredictable results.  In
       the future we may add additional flags that you can bitwise-or together
       with the mode, as well as additional modes.

       You can also pass 0 as the flags value in which case the database will
       be opened with the default flags.  However, these defaults may change
       in future releases.  The current default is MMDB_MODE_MMAP.

   MMDB_close()


           void MMDB_close(MMDB_s *const mmdb);


       This frees any allocated or mmap'd memory that is held from the MMDB_s
       structure.  It does not free the memory allocated for the structure
       itself! If you allocated the structure from the heap then you are
       responsible for freeing it.

   MMDB_lookup_string()


           MMDB_lookup_result_s MMDB_lookup_string(
               MMDB_s *const mmdb,
               const char *const ipstr,
               int *const gai_error,
               int *const mmdb_error);


       This function looks up an IP address that is passed in as a null-
       terminated string.  Internally it calls getaddrinfo() to resolve the
       address into a binary form.  It then calls MMDB_lookup_sockaddr() to
       look the address up in the database.  If you have already resolved an
       address you can call MMDB_lookup_sockaddr() directly, rather than
       resolving the address twice.



           int gai_error, mmdb_error;
           MMDB_lookup_result_s result =
               MMDB_lookup_string(&mmdb, "1.2.3.4", &gai_error, &mmdb_error);
           if (0 != gai_error) { ... }
           if (MMDB_SUCCESS != mmdb_error) { ... }

           if (result.found_entry) { ... }


       This function always returns an MMDB_lookup_result_s structure, but you
       should also check the gai_error and mmdb_error parameters.  If either
       of these indicates an error then the returned structure is meaningless.

       If no error occurred you still need to make sure that the found_entry
       member in the returned result is true.  If it's not, this means that
       the IP address does not have an entry in the database.

       This function will work with IPv4 addresses even when the database
       contains data for both IPv4 and IPv6 addresses.  The IPv4 address will
       be looked up as '::xxx.xxx.xxx.xxx' rather than being remapped to the
       ::ffff:xxx.xxx.xxx.xxx block allocated for IPv4-mapped IPv6 addresses.

       If you pass an IPv6 address to a database with only IPv4 data then the
       found_entry member will be false, but the mmdb_error status will still
       be MMDB_SUCCESS.

   MMDB_lookup_sockaddr()


           MMDB_lookup_result_s MMDB_lookup_sockaddr(
               MMDB_s *const mmdb,
               const struct sockaddr *const sockaddr,
               int *const mmdb_error);


       This function looks up an IP address that has already been resolved by
       getaddrinfo().

       Other than not calling getaddrinfo() itself, this function is identical
       to the MMDB_lookup_string() function.



           int mmdb_error;
           MMDB_lookup_result_s result =
               MMDB_lookup_sockaddr(&mmdb, address->ai_addr, &mmdb_error);
           if (MMDB_SUCCESS != mmdb_error) { ... }

           if (result.found_entry) { ... }


   Data Lookup Functions
       There are three functions for looking up data associated with an IP
       address.



           int MMDB_get_value(
               MMDB_entry_s *const start,
               MMDB_entry_data_s *const entry_data,
               ...);
           int MMDB_vget_value(
               MMDB_entry_s *const start,
               MMDB_entry_data_s *const entry_data,
               va_list va_path);
           int MMDB_aget_value(
               MMDB_entry_s *const start,
               MMDB_entry_data_s *const entry_data,
               const char *const *const path);


       The three functions allow three slightly different calling styles, but
       they all do the same thing.

       The first parameter is an MMDB_entry_s value.  In most cases this will
       come from the MMDB_lookup_result_s value returned by
       MMDB_lookup_string() or MMDB_lookup_sockaddr().

       The second parameter is a reference to an MMDB_entry_data_s structure.
       This will be populated with the data that is being looked up, if any is
       found.  If nothing is found, then the has_data member of this structure
       will be false.  If has_data is true then you can look at the data_type
       member.

       The final parameter is a lookup path.  The path consists of a set of
       strings representing either map keys (e.g, "city") or array indexes
       (e.g., "0", "1", "-1") to use in the lookup.

       Negative array indexes will be treated as an offset from the end of the
       array.  For instance, "-1" refers to the last element of the array.

       The lookup path allows you to navigate a complex data structure.  For
       example, given this data:



           {
               "names": {
                   "en": "Germany",
                   "de": "Deutschland"
               },
               "cities": [ "Berlin", "Frankfurt" ]
           }


       We could look up the English name with this code:



           MMDB_lookup_result_s result =
               MMDB_lookup_sockaddr(&mmdb, address->ai_addr, &mmdb_error);
           MMDB_entry_data_s entry_data;
           int status =
               MMDB_get_value(&result.entry, &entry_data,
                              "names", "en", NULL);
           if (MMDB_SUCCESS != status) { ... }
           if (entry_data.has_data) { ... }


       If we wanted to find the first city the lookup path would be "cities",
       "0".  If you don't provide a lookup path at all, you'll get the entry
       which corresponds to the top level map.  The lookup path must always
       end with NULL, regardless of which function you call.

       The MMDB_get_value function takes a variable number of arguments.  All
       of the arguments after the MMDB_entry_data_s * structure pointer are
       the lookup path.  The last argument must be NULL.

       The MMDB_vget_value function accepts a va_list as the lookup path.  The
       last element retrieved by va_arg() must be NULL.

       Finally, the MMDB_aget_value accepts an array of strings as the lookup
       path.  The last member of this array must be NULL.

       If you want to get all of the entry data at once you can call
       MMDB_get_entry_data_list() instead.

       For each of the three functions, the return value is a status code as
       defined above.

   MMDB_get_entry_data_list()


           int MMDB_get_entry_data_list(
               MMDB_entry_s *start,
               MMDB_entry_data_list_s **const entry_data_list);


       This function allows you to get all of the data for a complex data
       structure at once, rather than looking up each piece using repeated
       calls to MMDB_get_value().



           MMDB_lookup_result_s result =
               MMDB_lookup_sockaddr(&mmdb, address->ai_addr, &mmdb_error);
           MMDB_entry_data_list_s *entry_data_list, *first;
           int status =
               MMDB_get_entry_data_list(&result.entry, &entry_data_list);
           if (MMDB_SUCCESS != status) { ... }
           // save this so we can free this data later
           first = entry_data_list;

           while (1) {
               MMDB_entry_data_list_s *next = entry_data_list = entry_data_list->next;
               if (NULL == next) {
                   break;
               }

               switch (next->entry_data.type) {
                   case MMDB_DATA_TYPE_MAP: { ... }
                   case MMDB_DATA_TYPE_UTF8_STRING: { ... }
                   ...
               }

           }

           MMDB_free_entry_data_list(first);


       It's up to you to interpret the entry_data_list data structure.  The
       list is linked in a depth-first traversal.  Let's use this structure as
       an example:



           {
               "names": {
                   "en": "Germany",
                   "de": "Deutschland"
               },
               "cities": [ "Berlin", "Frankfurt" ]
           }


       The list will consist of the following items:

        1. MAP - top level map

        2. UTF8_STRING - "names" key

        3. MAP - map for "names" key

        4. UTF8_STRING - "en" key

        5. UTF8_STRING - value for "en" key

        6. UTF8_STRING - "de" key

        7. UTF8_STRING - value for "de" key

        8. UTF8_STRING - "cities" key

        9. ARRAY - value for "cities" key

       10. UTF8_STRING - array[0]

       11. UTF8_STRING - array[1]

       The return value of the function is a status code as defined above.

   MMDB_free_entry_data_list()


           void MMDB_free_entry_data_list(
               MMDB_entry_data_list_s *const entry_data_list);


       The MMDB_get_entry_data_list() and
       MMDB_get_metadata_as_entry_data_list() functions will allocate the
       linked list structure from the heap.  Call this function to free the
       MMDB_entry_data_list_s structure.

   MMDB_get_metadata_as_entry_data_list()


           int MMDB_get_metadata_as_entry_data_list(
               MMDB_s *const mmdb,
               MMDB_entry_data_list_s **const entry_data_list);


       This function allows you to retrieve the database metadata as a linked
       list of MMDB_entry_data_list_s structures.  This can be a more
       convenient way to deal with the metadata than using the metadata
       structure directly.



               MMDB_entry_data_list_s *entry_data_list, *first;
               int status =
                   MMDB_get_metadata_as_entry_data_list(&mmdb, &entry_data_list);
               if (MMDB_SUCCESS != status) { ... }
               first = entry_data_list;
               ... // do something with the data
               MMDB_free_entry_data_list(first);


       The return value of the function is a status code as defined above.

   MMDB_dump_entry_data_list()


           int MMDB_dump_entry_data_list(
               FILE *const stream,
               MMDB_entry_data_list_s *const entry_data_list,
               int indent);


       This function takes a linked list of MMDB_entry_data_list_s structures
       and stringifies it to the given stream.  The indent parameter is the
       starting indent level for the generated output.  It is incremented for
       nested data structures (maps, array, etc.).

       The stream must be a file handle (stdout, etc).  If your platform
       provides something like the GNU open_memstream() you can use that to
       capture the output as a string.

       The output is formatted in a JSON-ish fashion, but values are marked
       with their data type (except for maps and arrays which are shown with
       "{}" and "[]" respectively).

       The specific output format may change in future releases, so you should
       not rely on the specific formatting produced by this function.  It is
       intended to be used to show data to users in a readable way and for
       debugging purposes.

       The return value of the function is a status code as defined above.

   MMDB_read_node()


           int MMDB_read_node(
               MMDB_s *const mmdb,
               uint32_t node_number,
               MMDB_search_node_s *const node);


       This reads a specific node in the search tree.  The third argument is a
       reference to an MMDB_search_node_s structure that will be populated by
       this function.

       The return value is a status code.  If you pass a node_number that is
       greater than the number of nodes in the database, this function will
       return MMDB_INVALID_NODE_NUMBER_ERROR, otherwise it will return
       MMDB_SUCCESS.

       The first node in the search tree is always node 0.  If you wanted to
       iterate over the whole search tree, you would start by reading node 0
       and then following the the records that make up this node, based on the
       type of each record.  If the type is MMDB_RECORD_TYPE_SEARCH_NODE then
       the record contains an integer for the next node to look up.

   MMDB_lib_version()


           const char *MMDB_lib_version(void)


       This function returns the library version as a string, something like
       "2.0.0".


EXAMPLE



           #include <errno.h>
           #include <maxminddb.h>
           #include <stdlib.h>
           #include <string.h>

           int main(int argc, char **argv)
           {
               char *filename = argv[1];
               char *ip_address = argv[2];

               MMDB_s mmdb;
               int status = MMDB_open(filename, MMDB_MODE_MMAP, &mmdb);

               if (MMDB_SUCCESS != status) {
                   fprintf(stderr, "\n  Can't open %s - %s\n",
                           filename, MMDB_strerror(status));

                   if (MMDB_IO_ERROR == status) {
                       fprintf(stderr, "    IO error: %s\n", strerror(errno));
                   }
                   exit(1);
               }

               int gai_error, mmdb_error;
               MMDB_lookup_result_s result =
                   MMDB_lookup_string(&mmdb, ip_address, &gai_error, &mmdb_error);

               if (0 != gai_error) {
                   fprintf(stderr,
                           "\n  Error from getaddrinfo for %s - %s\n\n",
                           ip_address, gai_strerror(gai_error));
                   exit(2);
               }

               if (MMDB_SUCCESS != mmdb_error) {
                   fprintf(stderr,
                           "\n  Got an error from libmaxminddb: %s\n\n",
                           MMDB_strerror(mmdb_error));
                   exit(3);
               }

               MMDB_entry_data_list_s *entry_data_list = NULL;

               int exit_code = 0;
               if (result.found_entry) {
                   int status = MMDB_get_entry_data_list(&result.entry,
                                                         &entry_data_list);

                   if (MMDB_SUCCESS != status) {
                       fprintf(
                           stderr,
                           "Got an error looking up the entry data - %s\n",
                           MMDB_strerror(status));
                       exit_code = 4;
                       goto end;
                   }

                   if (NULL != entry_data_list) {
                       MMDB_dump_entry_data_list(stdout, entry_data_list, 2);
                   }
               } else {
                   fprintf(
                       stderr,
                       "\n  No entry for this IP address (%s) was found\n\n",
                       ip_address);
                   exit_code = 5;
               }

               end:
                   MMDB_free_entry_data_list(entry_data_list);
                   MMDB_close(&mmdb);
                   exit(exit_code);
           }



REQUIREMENTS

       libmaxminddb requires a minimum of POSIX.1-2001 support.  If not
       specified at compilation time, it defaults to requesting POSIX.1-2008
       support.


THREAD SAFETY

       This library is thread safe when compiled and linked with a thread-safe
       malloc and free implementation.


INSTALLATION AND SOURCE

       You can download the latest release of libmaxminddb from GitHub
       (https://github.com/maxmind/libmaxminddb/releases).

       Our GitHub repo (https://github.com/maxmind/libmaxminddb) is publicly
       available.  Please fork it!


BUG REPORTS AND PULL REQUESTS

       Please report all issues to our GitHub issue tracker
       (https://github.com/maxmind/libmaxminddb/issues).  We welcome bug
       reports and pull requests.  Please note that pull requests are greatly
       preferred over patches.


AUTHORS

       This library was written by Boris Zentner (bzentner@maxmind.com) and
       Dave Rolsky (drolsky@maxmind.com).


COPYRIGHT AND LICENSE

       Copyright 2013-2023 MaxMind, Inc.

       Licensed under the Apache License, Version 2.0 (the "License"); you may
       not use this file except in compliance with the License.  You may
       obtain a copy of the License at



           https://www.apache.org/licenses/LICENSE-2.0


       Unless required by applicable law or agreed to in writing, software
       distributed under the License is distributed on an "AS IS" BASIS,
       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
       implied.  See the License for the specific language governing
       permissions and limitations under the License.


SEE ALSO

       mmdblookup(1)

                                                               libmaxminddb(3)

libmaxminddb 1.8.0 - Generated Sat Nov 18 09:42:20 CST 2023
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