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* geoip: read source IP from EDNS0 subnet if provided This patch implements EDNS backend processing (similar in powerdns: https://doc.powerdns.com/authoritative/settings.html#setting-edns-subnet-processing). This feature comes very handy to test whether your geo config is working properly. Signed-off-by: Balazs Nagy <julsevern@gmail.com>
108 lines
2.8 KiB
Go
108 lines
2.8 KiB
Go
// Package geoip implements a max mind database plugin.
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package geoip
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import (
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"context"
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"fmt"
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"net"
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"path/filepath"
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"github.com/coredns/coredns/plugin"
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clog "github.com/coredns/coredns/plugin/pkg/log"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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"github.com/oschwald/geoip2-golang"
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)
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var log = clog.NewWithPlugin(pluginName)
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// GeoIP is a plugin that add geo location data to the request context by looking up a maxmind
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// geoIP2 database, and which data can be later consumed by other middlewares.
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type GeoIP struct {
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Next plugin.Handler
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db db
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edns0 bool
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}
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type db struct {
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*geoip2.Reader
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// provides defines the schemas that can be obtained by querying this database, by using
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// bitwise operations.
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provides int
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}
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const (
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city = 1 << iota
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)
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var probingIP = net.ParseIP("127.0.0.1")
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func newGeoIP(dbPath string, edns0 bool) (*GeoIP, error) {
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reader, err := geoip2.Open(dbPath)
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if err != nil {
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return nil, fmt.Errorf("failed to open database file: %v", err)
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}
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db := db{Reader: reader}
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schemas := []struct {
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provides int
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name string
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validate func() error
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}{
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{name: "city", provides: city, validate: func() error { _, err := reader.City(probingIP); return err }},
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}
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// Query the database to figure out the database type.
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for _, schema := range schemas {
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if err := schema.validate(); err != nil {
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// If we get an InvalidMethodError then we know this database does not provide that schema.
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if _, ok := err.(geoip2.InvalidMethodError); !ok {
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return nil, fmt.Errorf("unexpected failure looking up database %q schema %q: %v", filepath.Base(dbPath), schema.name, err)
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}
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} else {
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db.provides |= schema.provides
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}
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}
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if db.provides&city == 0 {
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return nil, fmt.Errorf("database does not provide city schema")
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}
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return &GeoIP{db: db, edns0: edns0}, nil
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}
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// ServeDNS implements the plugin.Handler interface.
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func (g GeoIP) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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return plugin.NextOrFailure(pluginName, g.Next, ctx, w, r)
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}
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// Metadata implements the metadata.Provider Interface in the metadata plugin, and is used to store
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// the data associated with the source IP of every request.
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func (g GeoIP) Metadata(ctx context.Context, state request.Request) context.Context {
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srcIP := net.ParseIP(state.IP())
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if g.edns0 {
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if o := state.Req.IsEdns0(); o != nil {
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for _, s := range o.Option {
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if e, ok := s.(*dns.EDNS0_SUBNET); ok {
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srcIP = e.Address
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break
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}
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}
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}
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}
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switch {
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case g.db.provides&city == city:
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data, err := g.db.City(srcIP)
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if err != nil {
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log.Debugf("Setting up metadata failed due to database lookup error: %v", err)
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return ctx
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}
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g.setCityMetadata(ctx, data)
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}
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return ctx
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}
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// Name implements the Handler interface.
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func (g GeoIP) Name() string { return pluginName }
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