coredns/plugin/kubernetes/handler.go
Miek Gieben 74ef6e00f1
transfer: reply with refused (#4510)
* transfer: reply with refused

When the *transfer* plugin is not loaded and of the handlers will still
see the AXFR/IXFR request because it is not intercepted.

They need to reply with REFUSED in that case. Update file, auto and k8s
to do this. Add testcase in the file plugin.

Ideally *erratic* should be moved over as well, but maybe that's
*erratic*

This is a bug fix.

Signed-off-by: Miek Gieben <miek@miek.nl>

* import path

Signed-off-by: Miek Gieben <miek@miek.nl>
2021-03-09 12:17:34 -08:00

91 lines
2.7 KiB
Go

package kubernetes
import (
"context"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
)
// ServeDNS implements the plugin.Handler interface.
func (k Kubernetes) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
state := request.Request{W: w, Req: r}
qname := state.QName()
zone := plugin.Zones(k.Zones).Matches(qname)
if zone == "" {
return plugin.NextOrFailure(k.Name(), k.Next, ctx, w, r)
}
zone = qname[len(qname)-len(zone):] // maintain case of original query
state.Zone = zone
var (
records []dns.RR
extra []dns.RR
err error
)
switch state.QType() {
case dns.TypeA:
records, err = plugin.A(ctx, &k, zone, state, nil, plugin.Options{})
case dns.TypeAAAA:
records, err = plugin.AAAA(ctx, &k, zone, state, nil, plugin.Options{})
case dns.TypeTXT:
records, err = plugin.TXT(ctx, &k, zone, state, nil, plugin.Options{})
case dns.TypeCNAME:
records, err = plugin.CNAME(ctx, &k, zone, state, plugin.Options{})
case dns.TypePTR:
records, err = plugin.PTR(ctx, &k, zone, state, plugin.Options{})
case dns.TypeMX:
records, extra, err = plugin.MX(ctx, &k, zone, state, plugin.Options{})
case dns.TypeSRV:
records, extra, err = plugin.SRV(ctx, &k, zone, state, plugin.Options{})
case dns.TypeSOA:
records, err = plugin.SOA(ctx, &k, zone, state, plugin.Options{})
case dns.TypeAXFR, dns.TypeIXFR:
return dns.RcodeRefused, nil
case dns.TypeNS:
if state.Name() == zone {
records, extra, err = plugin.NS(ctx, &k, zone, state, plugin.Options{})
break
}
fallthrough
default:
// Do a fake A lookup, so we can distinguish between NODATA and NXDOMAIN
fake := state.NewWithQuestion(state.QName(), dns.TypeA)
fake.Zone = state.Zone
_, err = plugin.A(ctx, &k, zone, fake, nil, plugin.Options{})
}
if k.IsNameError(err) {
if k.Fall.Through(state.Name()) {
return plugin.NextOrFailure(k.Name(), k.Next, ctx, w, r)
}
if !k.APIConn.HasSynced() {
// If we haven't synchronized with the kubernetes cluster, return server failure
return plugin.BackendError(ctx, &k, zone, dns.RcodeServerFailure, state, nil /* err */, plugin.Options{})
}
return plugin.BackendError(ctx, &k, zone, dns.RcodeNameError, state, nil /* err */, plugin.Options{})
}
if err != nil {
return dns.RcodeServerFailure, err
}
if len(records) == 0 {
return plugin.BackendError(ctx, &k, zone, dns.RcodeSuccess, state, nil, plugin.Options{})
}
m := new(dns.Msg)
m.SetReply(r)
m.Authoritative = true
m.Answer = append(m.Answer, records...)
m.Extra = append(m.Extra, extra...)
w.WriteMsg(m)
return dns.RcodeSuccess, nil
}
// Name implements the Handler interface.
func (k Kubernetes) Name() string { return "kubernetes" }