geoip

README

geoip

Name

geoip - Lookup maxmind geoip2 databases using the client IP, then add associated geoip data to the context request.

Description

The geoip plugin add geo location data associated with the client IP, it allows you to configure a geoIP2 maxmind database to add the geo location data associated with the IP address.

The data is added leveraging the metadata plugin, values can then be retrieved using it as well, for example:

import (
    "strconv"
    "github.com/khulnasoft-lab/dnserver/plugin/metadata"
)
// ...
if getLongitude := metadata.ValueFunc(ctx, "geoip/longitude"); getLongitude != nil {
    if longitude, err := strconv.ParseFloat(getLongitude(), 64); err == nil {
        // Do something useful with longitude.
    }
} else {
    // The metadata label geoip/longitude for some reason, was not set.
}
// ...

Databases

The supported databases use city schema such as City and Enterprise. Other databases types with different schemas are not supported yet.

You can download a free and public City database.

Syntax

geoip [DBFILE]

or

geoip [DBFILE] {
    [edns-subnet]
}

• DBFILE the mmdb database file path. We recommend updating your mmdb database periodically for more accurate results.

• edns-subnet: Optional. Use EDNS0 subnet (if present) for Geo IP instead of the source IP of the DNS request. This helps identifying the closest source IP address through intermediary DNS resolvers, and it also makes GeoIP testing easy: dig +subnet=1.2.3.4 @dns-server.example.com www.geo-aware.com.

  NOTE: due to security reasons, recursive DNS resolvers may mask a few bits off of the clients' IP address, which can cause inaccuracies in GeoIP resolution.

  There is no defined mask size in the standards, but there are examples: RFC 7871's example conceals the last 72 bits of an IPv6 source address, and NS1 Help Center mentions that ECS-enabled DNS resolvers send only the first three octets (eg. /24) of the source IPv4 address.

Examples

The following configuration configures the City database, and looks up geolocation based on EDNS0 subnet if present.

. {
    geoip /opt/geoip2/db/GeoLite2-City.mmdb {
      edns-subnet
    }
    metadata # Note that metadata plugin must be enabled as well.
}

The view plugin can use geoip metadata as selection criteria to provide GSLB functionality. In this example, clients from the city "Exampleshire" will receive answers for example.com from the zone defined in example.com.exampleshire-db. All other clients will receive answers from the zone defined in example.com.db. Note that the order of the two example.com server blocks below is important; the default viewless server block must be last.

example.com {
    view exampleshire {
      expr metadata('geoip/city/name') == 'Exampleshire'
    }
    geoip /opt/geoip2/db/GeoLite2-City.mmdb
    metadata
    file example.com.exampleshire-db
}

example.com {
    file example.com.db
}

Metadata Labels

A limited set of fields will be exported as labels, all values are stored using strings regardless of their underlying value type, and therefore you may have to convert it back to its original type, note that numeric values are always represented in base 10.

Label	Type	Example	Description
geoip/city/name	string	Cambridge	Then city name in English language.
geoip/country/code	string	GB	Country ISO 3166-1 code.
geoip/country/name	string	United Kingdom	The country name in English language.
geoip/country/is_in_european_union	bool	false	Either true or false.
geoip/continent/code	string	EU	See Continent codes.
geoip/continent/name	string	Europe	The continent name in English language.
geoip/latitude	float64	52.2242	Base 10, max available precision.
geoip/longitude	float64	0.1315	Base 10, max available precision.
geoip/timezone	string	Europe/London	The timezone.
geoip/postalcode	string	CB4	The postal code.

Continent Codes

Value	Continent (EN)
AF	Africa
AN	Antarctica
AS	Asia
EU	Europe
NA	North America
OC	Oceania
SA	South America

Documentation

Overview

Package geoip implements a max mind database plugin.

Index

• type GeoIP
  • func (g GeoIP) Metadata(ctx context.Context, state request.Request) context.Context
  • func (g GeoIP) Name() string
  • func (g GeoIP) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

Types

type GeoIP

type GeoIP struct {
	Next plugin.Handler
	// contains filtered or unexported fields
}

GeoIP is a plugin that add geo location data to the request context by looking up a maxmind geoIP2 database, and which data can be later consumed by other middlewares.

func (GeoIP) Metadata

func (g GeoIP) Metadata(ctx context.Context, state request.Request) context.Context

Metadata implements the metadata.Provider Interface in the metadata plugin, and is used to store the data associated with the source IP of every request.

func (GeoIP) Name

func (g GeoIP) Name() string

Name implements the Handler interface.

func (GeoIP) ServeDNS

func (g GeoIP) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

ServeDNS implements the plugin.Handler interface.