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package kubernetes
import (
"context"
"strings"
"sync/atomic"
"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
)
if wildQuestion(state.Name()) {
atomic.AddUint64(&wildCount, 1)
}
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:
if qname == zone {
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
}
func wildQuestion(name string) bool {
return strings.HasPrefix(name, "*.") || strings.HasPrefix(name, "any.") || strings.Contains(name, ".*.") || strings.Contains(name, ".any.")
}
// Name implements the Handler interface.
func (k Kubernetes) Name() string { return "kubernetes" }
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