c1c98924c3
* Add new plugin: external This plugin works in conjunction with the kubernetes plugin and exports ingress and LB addresses as DNS records. It bypasses backend.go and backend_lookup.go flow because it is not needed. README, tests are implemented. The tests only exercise the unit tests, this has not been tested in any ci. Signed-off-by: Miek Gieben <miek@miek.nl> * Rename to k8s_external Signed-off-by: Miek Gieben <miek@miek.nl> * go gen Signed-off-by: Miek Gieben <miek@miek.nl>
110 lines
2.7 KiB
Go
110 lines
2.7 KiB
Go
package external
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import (
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"github.com/coredns/coredns/plugin/pkg/dnsutil"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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)
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// serveApex serves request that hit the zone' apex. A reply is written back to the client.
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func (e *External) serveApex(state request.Request) (int, error) {
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m := new(dns.Msg)
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m.SetReply(state.Req)
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switch state.QType() {
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case dns.TypeSOA:
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m.Answer = []dns.RR{e.soa(state)}
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case dns.TypeNS:
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m.Answer = []dns.RR{e.ns(state)}
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addr := e.externalAddrFunc(state)
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for _, rr := range addr {
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rr.Header().Ttl = e.ttl
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rr.Header().Name = state.QName()
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m.Extra = append(m.Extra, rr)
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}
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default:
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m.Ns = []dns.RR{e.soa(state)}
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}
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state.W.WriteMsg(m)
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return 0, nil
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}
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// serveSubApex serves requests that hit the zones fake 'dns' subdomain where our nameservers live.
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func (e *External) serveSubApex(state request.Request) (int, error) {
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base, _ := dnsutil.TrimZone(state.Name(), state.Zone)
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m := new(dns.Msg)
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m.SetReply(state.Req)
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// base is either dns. of ns1.dns (or another name), if it's longer return nxdomain
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switch labels := dns.CountLabel(base); labels {
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default:
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m.SetRcode(m, dns.RcodeNameError)
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m.Ns = []dns.RR{e.soa(state)}
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state.W.WriteMsg(m)
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return 0, nil
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case 2:
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nl, _ := dns.NextLabel(base, 0)
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ns := base[:nl]
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if ns != "ns1." {
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// nxdomain
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m.SetRcode(m, dns.RcodeNameError)
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m.Ns = []dns.RR{e.soa(state)}
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state.W.WriteMsg(m)
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return 0, nil
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}
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addr := e.externalAddrFunc(state)
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for _, rr := range addr {
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rr.Header().Ttl = e.ttl
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rr.Header().Name = state.QName()
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switch state.QType() {
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case dns.TypeA:
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if rr.Header().Rrtype == dns.TypeA {
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m.Answer = append(m.Answer, rr)
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}
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case dns.TypeAAAA:
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if rr.Header().Rrtype == dns.TypeAAAA {
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m.Answer = append(m.Answer, rr)
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}
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}
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}
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if len(m.Answer) == 0 {
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m.Ns = []dns.RR{e.soa(state)}
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}
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state.W.WriteMsg(m)
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return 0, nil
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case 1:
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// nodata for the dns empty non-terminal
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m.Ns = []dns.RR{e.soa(state)}
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state.W.WriteMsg(m)
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return 0, nil
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}
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}
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func (e *External) soa(state request.Request) *dns.SOA {
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header := dns.RR_Header{Name: state.Zone, Rrtype: dns.TypeSOA, Ttl: e.ttl, Class: dns.ClassINET}
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soa := &dns.SOA{Hdr: header,
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Mbox: dnsutil.Join(e.hostmaster, e.apex, state.Zone),
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Ns: dnsutil.Join("ns1", e.apex, state.Zone),
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Serial: 12345, // Also dynamic?
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Refresh: 7200,
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Retry: 1800,
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Expire: 86400,
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Minttl: e.ttl,
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}
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return soa
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}
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func (e *External) ns(state request.Request) *dns.NS {
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header := dns.RR_Header{Name: state.Zone, Rrtype: dns.TypeNS, Ttl: e.ttl, Class: dns.ClassINET}
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ns := &dns.NS{Hdr: header, Ns: dnsutil.Join("ns1", e.apex, state.Zone)}
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return ns
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}
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