NAME

    gdnsd-plugin-geoip - gdnsd meta-plugin for GSLB + failover via MaxMind's
    GeoIP databases

SYNOPSIS

    Minimal example gdnsd config file using this plugin:

      plugins => { geoip => {
        maps => {
          my_prod_map => {
            geoip_db => GeoIPCity.dat,
            datacenters => [dc-03, dc-02, dc-01],
            map => {
                EU => {
                    DE => [dc-03, dc-01],
                    CH => [dc-01, dc-03]
                },
                NA => { MX => [dc-02] }
            }
          },
          my_auto_map => {
            geoip_db => GeoIPCityv6.dat,
            datacenters => [dc1, dc2],
            auto_dc_coords => {
               dc1 => [ 38.9, -77 ],
               dc2 => [ 50.1, 8.7 ],
            }
          }
        },
        resources => {
          prod_www => {
            map => my_prod_map
            service_types => default
            dcmap => {
              dc-01 => 192.0.2.1,
              dc-02 => { lb01 => 192.0.2.2, lb02 => 192.0.2.3 },
              dc-03 => [ 192.0.2.4, 192.0.2.5, 192.0.2.6 ]
            }
          }
          corp_www => {
            map => my_auto_map
            dcmap => {
              dc1 => 192.0.2.100,
              dc2 => 192.0.2.101
            }
          }
        }
      }}

    Example zonefile RRs:

      www      600 DYNA geoip!prod_www
      www-dc01 600 DYNA geoip!prod_www/dc-01
      www.corp 600 DYNA geoip!corp_www

DESCRIPTION

    gdnsd-plugin-geoip uses MaxMind's GeoIP binary databases to map address
    and CNAME results based on geography and (in the address case) monitored
    service availability. It fully supports both IPv6 and the emerging
    edns-client-subnet standard. If a request contains the
    edns-client-subnet option with a source netmask greater than zero, the
    edns-client-subnet information will be used instead of the source IP of
    the request (the IP of the querying cache).

    This plugin can operate in an automatic distance-based mode (using
    City-level coordinate information rather than an external file and a
    Region-level db). It can also operate coordinate-free and rely on the
    user to configure a hierarchical map of cascading default
    user-location-to-datacenter mappings, starting at the continent level.

    The two modes can also be effectively mixed at geographic boundaries.

    For each "map" you define (which maps geographic location codes to
    preference-ordered lists of your datacenter locations), this plugin
    merges all of the raw GeoIP subnets into the largest possible supernets
    which contain identical responses in your configuration. These in turn
    are used to set larger edns-client-subnet scope masks than you'd see
    simply returning raw GeoIP results.

PLUGIN_METAFO

    The documentation for gdnsd-plugin-metafo(8) is required reading for
    understanding the geoip plugin documentation here. The geoip plugin is
    an exact superset of the metafo plugin, and re-uses almost all of the
    metafo plugin's source code. What plugin_geoip adds on top of the
    functionality of metafo is the ability to have the order of the
    datacenter failover list become dynamic per-request based on geographic
    hints derived from the client's network address, as well as the ability
    to do geographic selection of DYNC (CNAME) resources.

FILE LOCATIONS

    The configuration of this plugin can reference several external
    configuration and/or data files. The location of these files is
    dependent, of course, on whether the daemon is running in chroot or
    "system paths" mode. In system paths mode, the directory for these files
    is commonly, e.g. /etc/gdnsd/geoip/ given autoconf $sysconfdir of /etc.
    In chroot mode, the directory would be /srv/gdnsd/etc/geoip/ given a
    chroot directory of /srv/gdnsd. If any of the pathnames are specified as
    absolute paths, they will be taken literally (although this will still
    be relative to the chroot in the chroot case).

CONFIGURATION - TOP-LEVEL

    The top level of the geoip plugin's configuration (i.e. "plugins => {
    geoip => { ... } }") supports only two special keys, both of which are
    required and expanded upon in detail in the next two sections: "maps",
    and "resources". The "maps" section defines one or more named mappings
    of location information from GeoIP binary databases to ordered subsets
    of datacenter names. The "resources" section defines one or more named
    resources, each of which references one of the named maps and resolves
    datacenter names to specific sets of addresses or CNAMEs.

    Any other keys present at this level will be inherited down inside of
    each per-resource hash inside the "resources" stanza, acting as
    per-resource defaults for anything not defined explicitly there.

CONFIGURATION - MAPS

    The "maps" stanza supports one special configuration key at the top
    level:

  "city_region_names = region_codes.csv"

    String, filename, optional. GeoIP City databases use FIPS 10-4 codes for
    the names of Regions outside of the US and Canada, and two-letter
    national alpha codes within the US and Canada. For example the Geneve
    region of Switzerland is identified as 07 in the database. By default
    you would have to use these relatively confusing region codes in your
    hierarchical maps that make use of Region-level information (e.g. "EU =>
    { CH => { 07 => { Geneva => [ ... ] } } } }". If this option is
    specified, it points to a text file that maps these FIPS codes to
    canonical, memorable full names for clearer map configuration (e.g. "EU
    => { CH => { Geneve => { Geneva => [ ... ] } } } }". Note that while
    older versions of this data did not map the US/Canadian two-letter alpha
    codes, newer versions do (e.g. TX -> Texas).

    This setting does not affect the GeoIP "Region" -format databases, which
    have no region codes outside of the US and Canada, and always need the
    two-letter alpha codes in the map.

    The file format is a simple subset of the CSV format with 3 fields: ISO
    3166-1 country code, FIPS 10-4 region code (or two-letter alpha in
    US/Canada), and the region name in double-quotes. It is recommended you
    download this file directly from MaxMind's reference copy in this
    format. As of this writing, it is available from them at the following
    URL: <http://dev.maxmind.com/static/maxmind-region-codes.csv>.

CONFIGURATION - PER-MAP

    All other "maps"-level configuration keys are the names of the maps you
    choose to define. A map, conceptually, is a mapping between geography
    and/or network topology to varying ordered datacenter sub-sets. The
    value of each named map must be a hash, and the following configuration
    keys apply within:

  "geoip_db = GeoIPv6.dat"

    String, filename, optional. This is the filename of one of the supported
    MaxMind GeoIP database types. It will be reloaded at runtime (without
    any significant query interruptions) if a change to the database file is
    detected.

  "geoip_db_v4_overlay = GeoIP.dat"

    String, pathname, optional. This specifies an optional IPv4-level GeoIP
    database to overwrite the IPv4 sub-space of the IPv6 data loaded from
    "geoip_db". It must be a V4-format database, and "geoip_db" must be
    defined as a V6-format database. In all other respects, it is similar to
    "geoip_db".

    As of this writing, MaxMind doesn't sell a commercial GeoIPv6 database.
    What they offer are free IPv6 GeoLite database downloads, which include
    the IPv4 subset in the less-accurate GeoLite form. This option allows
    you to use these GeoLitev6 databases for IPv6 coverage, and then overlay
    your paid commercial GeoIPv4 data on top for more accurate IPv4 results.

  "datacenters = [ one, two, three, ... ]"

    Array of strings, required. This is the total set of datacenter names
    used by this map. You must define at least one datacenter name (although
    2 or more would be infinitely more useful). At this time, there is a
    maximum limit of 254 datacenter names per map, although this could be
    raised if anyone requires it. The order specified here is the fallback
    default result ordering in various default cases (e.g. if no explicit
    top-level map default list is given).

  "city_no_region = true"

    Boolean, default "false". If this key is set to "true" and "geoip_db"
    references a City-level database, the Region-level information within it
    will be completely ignored for mapping purposes. Your hierarchical map
    structure will now be "continent => country => city" rather than
    "continent => country => region => city".

  "nets = { ... }"

    Key-value hash, optional (see below for alternate form). If specified,
    the contents should be key-value pairs of "network/netmask" mapped to a
    datacenter name (or an array of datacenter names). Any
    network-to-datacenter mappings specified here will override mappings
    determined via GeoIP. Note that it is illegal to specify networks in the
    IPv4-like subspaces of IPv6 other than v4compat, but it is legal to
    specify actual IPv4 networks (which are treated identically to
    v4compat). See the section on IPv4 Compatible Addresses later in this
    document for more details. The order of the networks is unimportant;
    they will always be sorted and inserted such that an entry which is a
    subnet of another entry is not obliterated by the parent supernet.

        nets => {
            10.0.0.0/8 => [ dc1, dc2 ],
            192.0.2.128/25 => dc3
            2001:DB8::/32 => [ dc4, dc5, dc6 ],
        }

    In the case that one entry is a subnet of another with a different
    result dclist, the entries are merged correctly such that the supernet
    surrounds the subnet. In the case of an exact duplicate entry (or an
    effective one, after merging smaller subnets) with a different dclist,
    it is arbitrary which one "wins" and the condition is warned about. If
    you care about this case, you should sanitize your nets data beforehand
    with an external tool and/or parse for the warning message in log
    outputs.

  "nets = nets_file_name"

    String pathname, optional. A variant of the above, but the contents of
    the key-value hash are loaded from the named external file. This makes
    life easier for external tools and scripts generating large sets of nets
    entries (e.g. from BGP data). The file will be monitored for changes and
    reloaded at runtime much like the GeoIP databases.

  "map = { ... }"

    Key-value hash, optional. This is the heart of a named map which uses
    GeoIP: the map itself, which maps places to ordered lists of
    datacenters. It requires that "geoip_db" is also specified, and makes no
    sense without it.

    This is a nested key-value hash. At each level, the keys are location
    codes (continent, country, region, or city information depending on
    depth), and the values are either an ordered datacenter array (e.g. "[
    dc03, dc01, dc04 ]"), or a sub-hash containing a deeper level of
    distinction. At each layer, a special key named "default" is available,
    which sets the default for everything within the current scope. The
    top-level default itself defaults to the ordered list from "datacenters"
    in the normal case. If the entire "map" stanza is missing or empty, you
    just get the default behavior of "default". A datacenter array can also
    be empty, which implies that this location is mapped to receive no
    response data (the server will still respond to the query, and will not
    issue an NXDOMAIN. It will simply be a NODATA/NOERROR response like
    you'd get if there were no records of this type, but could be records of
    other types for the same name).

    The meaningful location keys at the top level are continent codes, of
    which there are primarily seven in MaxMind's databases: "AF" for Africa,
    "AS" for Asia, "NA" for North America, "SA" for South America, "EU" for
    Europe, "OC" for Oceania, and "AN" for Antarctica. There is also an
    eighth continent-level code which is, literally, "--". This is a sort of
    fallback "no information available" continent code, and it contains the
    special country codes "A1", "A2", "O1", and "--", which represent
    Anonymous Proxies, Satellite Providers, Other, and Unknown,
    respsectively.

    The next layer (the sub-hash beneath any continent code) maps ISO-3166-1
    2-letter country codes, which as with continents can map directly to
    datacenters, or to yet another recursive layer.

    The next two layers deep are for Region and City level information, only
    available from the Region and City type databases. The Region database
    type only provides region information for the US and Canada, using the
    standard local 2-letter abbrevations (e.g. AB for Alberta, OK for
    Oklahama). The City databases use those same region abbrevations for the
    US and Canada, but use either FIPS 10-4 2-letter codes or full region
    names for the rest of the world's regions (as detailed earlier in, and
    controlled by, the "city_region_names" option).

    The actual City names at the final layer appear to be encoded using some
    form of ISO8859-1 and/or CP1252 character set in the databases
    themselves, and your map entries will have to match byte-for-byte in the
    case of non-ASCII characters. May come up with a better solution for
    this down the road.

    There is also one other special key (aside from "default") available at
    all levels of the map hierarchy, a boolean named "skip_level", default
    "false". If set within the hierarchical "map" at any layer, it causes
    the next layer of detail to be skipped for this portion of the map. For
    example, setting this at the very top layer would mean that the top
    layer would contain country-level codes directly, without an enclosing
    continent-level hierarchy. Setting it within a country would mean that
    city names are used directly within that country, without an intervening
    layer of region names. This option is not aware of the "city_no_region"
    option, so e.g. setting that option and specifying "skip_level" at the
    country-level would result in no further information being available
    within that country (as "skip_level" would skip the remaining layer of
    city data).

CONFIGURATION - MAPS - CITY AUTO MODE

    "City-auto-mode" is a special mode of operation that automatically maps
    out the world to your datacenters based on coordinate math, so that you
    don't have to manually construct a complex hierarchical "map". It can
    still be mixed with "map" of course, allowing you to use auto-mode for
    only select geographic areas if you wish (or disabling it for select
    areas by specifying manual lists). The key parameter is
    "auto_dc_coords", which enables city-auto-mode.

    "auto_dc_coords = { ... }"
        Key-value hash, optional. If this option is specified, the whole
        map's basic mode of operation changes to "city-auto-mode". The
        contents of the hash are a key for each datacenter named in
        "datacenters", with their values set to an array of "[lat, lon]" in
        decimal degree units. When city-auto-mode is enabled by this, the
        following configuration-validation changes occur from the default,
        static-mapping mode: the loaded GeoIP database(s) are required be
        City-level databases, and the special keyword "auto" becomes a legal
        "datacenter list" in the "map" stanza.

        With city-auto-mode enabled, the top-level map "default" defaults to
        "auto", but can be overridden with a manual list. For any location
        that maps to "auto", the coordinates specified here in
        "auto_dc_coords" will be compared with the coordinates from the
        City-level database(s) to determine an automatic distance-sorted
        datacenter list.

        If you omit one or more defined datacenters from the coordinate list
        in "auto_dc_coords", those datacenters will not be used in automatic
        results, but will still be available for manual use via "map" and/or
        "nets" entries.

    "auto_dc_limit = N"
        Unsigned integer, optional, default 3. When city-auto-mode is in
        effect, this is the upper length limit for auto-generated lists. 3
        is a reasonable default even if you have a considerably longer set
        of datacenters, as this provides a primary as well as two fallbacks.
        Raising this to a large number in the presence of a long datacenter
        list will cause the set of unique result datacenter lists to
        increase rapidly, and thus reduce the optimization of the final
        result database for edns-client-subnet purposes. It's really not
        worth raising this value in almost any case, unless you really need
        to handle more than 3 random datacenters going offline at the same
        time and still have clients fail elsewhere. The value zero is
        treated as unlimited (highly un-recommended).

    Under city-auto-mode, when the top-level default is (explicitly or
    implicitly) "auto", there is still a fallback static ordering which is
    the whole ordered "datacenters" list, which is the normal static default
    "default" when not in city-auto-mode. This fallback is used when no
    location information is available at all (e.g. IPv6 client vs IPv4 GeoIP
    DB, Anonymous Proxies, etc).

MAP TESTING

    A binary program "gdnsd_geoip_test" is included. This can be used
    directly from the commandline, parses the relevant bits of your gdnsd
    config file for geoip map info, and then provides datacenter list
    results for IP address + map combinations supplied by the user. Useful
    for debugging your maps and testing the mapping of client IPs. It has a
    separate manpage gdnsd_geoip_test(1).

CONFIGURATION - RESOURCES

    Resource-level configuration within the "resources" stanza is nearly
    identical to the resources configuration of the metafo plugin, with all
    of the same basic behaviors about synthesizing or directly referencing
    the configuration of other plugins per-datacenter. Only the key
    differences will be covered here:

    *   metafo's per-resource "datacenters" array is replaced with "map =>
        mapname", which references one of the maps defined in the "maps"
        stanza, described in detail earlier. The set of defined datacenters
        in the "dcmap" stanza must match the total set of datacenters
        defined by the referenced map.

    *   metafo's restriction to just address-based (DYNA) results is lifted.
        If the per-resource sub-plugin configurations used by a geoip
        resource support CNAME (DYNC) results, then that geoip resource will
        also support DYNC results. Because there is no DYNC monitoring, only
        the first datacenter from each datacenter sub-list in the "map" will
        be used for the result; there is no failover, only geographic
        differentiation.

    *   For the common case of a single CNAME result per-datacenter, the
        CNAME data can be supplied directly as the singular string value of
        each datacenter in the "dcmap", without involving a sub-plugin at
        all.

META-PLUGIN INTERACTION

    Both of the meta-plugins ("metafo" and "geoip") can reference their own
    as well as each others' resources by direct reference within a "dcmap",
    so long as a resource does not directly refer to itself. This allows
    plugin-layering configurations such as geoip -> metafo -> weighted, or
    metafo -> geoip -> multifo, or even metafo -> metafo -> simplefo, etc.

    Bear in mind that once you begin using inter-meta-plugin references, you
    could create a reference loop. gdnsd does not currently detect or
    prevent such loops, and they will cause complete runtime failure when
    queried, probably by running out of stack space during recursion.

    Additionally, "geoip" can synthesize configuration for "metafo"
    resources, but the reverse does not hold; "metafo" cannot synthesize
    configuration for "geoip" resources.

IPv4 Compatible Addresses

    This plugin knows of five different relatively-trivial ways to map IPv4
    addresses into the IPv6 address space. These are shown below, with
    "NNNN:NNNN" in place of the copied IPv4 address bytes:

       ::NNNN:NNNN/96        # v4compat - canonical form for this plugin
       ::FFFF:NNNN:NNNN/96   # v4mapped
       ::FFFF:0:NNNN:NNNN/96 # SIIT
       2001::NNNN:NNNN/32    # Teredo (NNNN:NNNN is xor'd with FFFF:FFFF)
       2002:NNNN:NNNN::/16   # 6to4

    All of this plugin's internal lookup databases are IPv6 databases, and
    any IPv4-like information is always stored in the v4compat space within
    these databases. When doing runtime lookups all other v4-like addresses
    (raw IPv4 addresses, v4mapped, SIIT, Teredo, and 6to4) are converted to
    the canonical v4compat IPv6 representation before querying the internal
    databases. The other representations (v4mapped, SIIT, Teredo, 6to4) are
    Undefined internally, and will never be referenced at lookup-time due to
    the v4compat conversion mentioned earlier.

    The "nets" stanza is not allowed to specify entries in the four
    undefined v4-like IPv6 spaces (those other than v4compat). Specify those
    networks as normal IPv4 networks or v4compat networks instead.
    Legitimate IPv6 "nets" entries which happen to be a supernet of any
    v4-like spaces will *not* undely affect v4-like lookups. There is no
    functional difference between v4compat and native v4 forms in "nets",
    e.g. "192.0.2.0/24" and "::C000:0200/120" are completely identical.

    GeoIP databases that are natively IPv4-only get all of their data loaded
    into the v4compat space only. For IPv6 GeoIP databases, by default we
    load the v4compat space directly (which is where MaxMind stores IPv4
    data in their IPv6 databases), but ignore the v4mapped/SIIT/Teredo/6to4
    spaces (some of which are empty in MaxMind's databases, and some of
    which simply alias the v4compat space). When using an IPv6 GeoIP
    database combined with an IPv4 GeoIP overlay (geoip_db_v4_overlay
    config), the v4compat space of the IPv6 database is also ignored on
    loading, and the direct IPv4 data from the IPv4 databasee takes its
    place.

ANOTHER CONFIG EXAMPLE

    A relatively-maximal example config, showing the interaction of valid
    "maps" and "resources" sections:

      service_types => {
        xmpp_svc => { plugin => "tcp_connect", ... }
        www_svc => { plugin => "http_status", ... }
      }
      plugins => {
        geoip => {
          maps => {
            city_region_names => fips_include,
            my_prod_map => {
              geoip_db => GeoIPCityv6.dat,
              geoip_db_v4_overlay => GeoIPCity.dat,
              city_no_region => false, # default
              datacenters => [us-01, de-01, sg-01],
              map => {
                  # Hierarchy is Continent -> Country -> Region -> City
                  NA => {
                    US => {
                      skip_level => 1, # skip past region level
                      Dallas => [sg-01],
                    }
                  }
                  SA => [us-01, sg-01, de-01],
                  EU => {
                    default => [eu-01, us-01, sg-01],
                    CH => {
                      Geneve => {
                        Geneva => [sg-01],
                      }
                    }
                  }
                  AF => [eu-01, us-01, sg-01],
                  AS => [sg-01, eu-01, us-01],
                  OC => [sg-01, us-01, eu-01],
              }
              nets => {
                  10.0.0.0/8 => [ eu-01 ],
                  2001:DB8::/32 => [ us-01 ],
              }
            }
            my_auto_map => {
              geoip_db => GeoIPCityv6.dat,
              geoip_db_v4_overlay => GeoIPCity.dat,
              datacenters => [us-01, de-01, sg-01],
              auto_dc_coords => {
                 us-01 => [ 38.9, -77 ],
                 de-01 => [ 50.1, 8.7 ],
                 sg-01 => [ 1.3, 103.9 ],
              }
            }
          }
          resources => {
            prod_app => {
              map => my_auto_map
              # these two are inherited multifo config keys
              #  for all of the dcmap below:
              service_types => [www_svc, xmpp_svc],
              up_thresh => 0.4,
              dcmap => {
                us-01 => {
                  lb01 => 192.0.2.1,
                  lb02 => 192.0.2.2,
                  lb03 => 192.0.2.3,
                  lb01.v6 => 2001:DB8::1,
                  lb02.v6 => 2001:DB8::2,
                  lb03.v6 => 2001:DB8::3,
                },
                sg-01 => {
                  lb01 => 192.0.2.4,
                  lb02 => 192.0.2.5,
                  lb03 => 192.0.2.6,
                  lb01.v6 => 2001:DB8::4,
                  lb02.v6 => 2001:DB8::5,
                  lb03.v6 => 2001:DB8::6,
                },
                de-01 => {
                  lb01 => 192.0.2.7,
                  lb02 => 192.0.2.8,
                  lb03 => 192.0.2.9,
                  lb01.v6 => 2001:DB8::7,
                  lb02.v6 => 2001:DB8::8,
                  lb03.v6 => 2001:DB8::9,
                },
              }
            },
            prod_cdn => {
              map => my_prod_map,
              dcmap => {
                us-01 => us-cdn-provider.example.com.
                sg-01 => asia-cdn-provider.example.com.
                de-01 => europe-cdn-provider.example.com.
              }
            }
          }
        }
      }

    Example zonefile RRs:

      app     600 DYNA geoip!prod_app
      app.us  600 DYNA geoip!prod_app/us-01
      app.sg  600 DYNA geoip!prod_app/sg-01
      app.de  600 DYNA geoip!prod_app/de-01
      content 600 DYNC geoip!prod_cdn

SEE ALSO

    gdnsd-plugin-metafo(8), gdnsd_geoip_test(1), gdnsd.config(5),
    gdnsd.zonefile(5), gdnsd(8)

    The gdnsd manual.

COPYRIGHT AND LICENSE

    Copyright (c) 2012 Brandon L Black <blblack@gmail.com>

    This file is part of gdnsd.

    gdnsd is free software: you can redistribute it and/or modify it under
    the terms of the GNU General Public License as published by the Free
    Software Foundation, either version 3 of the License, or (at your
    option) any later version.

    gdnsd is distributed in the hope that it will be useful, but WITHOUT ANY
    WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
    more details.

    You should have received a copy of the GNU General Public License along
    with gdnsd. If not, see <http://www.gnu.org/licenses/>.

