115 lines
2.9 KiB
Go
115 lines
2.9 KiB
Go
package kubernetes
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import (
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"fmt"
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"github.com/miekg/coredns/middleware"
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"github.com/miekg/coredns/middleware/pkg/dnsutil"
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"github.com/miekg/coredns/request"
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"github.com/miekg/dns"
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"golang.org/x/net/context"
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)
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// ServeDNS implements the middleware.Handler interface.
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func (k Kubernetes) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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state := request.Request{W: w, Req: r}
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if state.QClass() != dns.ClassINET {
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return dns.RcodeServerFailure, fmt.Errorf("can only deal with ClassINET")
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}
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m := new(dns.Msg)
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m.SetReply(r)
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m.Authoritative, m.RecursionAvailable, m.Compress = true, true, true
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// TODO: find an alternative to this block
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ip := dnsutil.ExtractAddressFromReverse(state.Name())
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if ip != "" {
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records := k.getServiceRecordForIP(ip, state.Name())
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if len(records) > 0 {
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srvPTR := &records[0]
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m.Answer = append(m.Answer, srvPTR.NewPTR(state.QName(), ip))
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m = dnsutil.Dedup(m)
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state.SizeAndDo(m)
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m, _ = state.Scrub(m)
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w.WriteMsg(m)
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return dns.RcodeSuccess, nil
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}
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}
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// Check that query matches one of the zones served by this middleware,
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// otherwise delegate to the next in the pipeline.
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zone := middleware.Zones(k.Zones).Matches(state.Name())
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if zone == "" {
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if k.Next == nil {
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return dns.RcodeServerFailure, nil
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}
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return k.Next.ServeDNS(ctx, w, r)
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}
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var (
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records, extra []dns.RR
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err error
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)
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switch state.Type() {
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case "A":
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records, err = k.A(zone, state, nil)
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case "AAAA":
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records, err = k.AAAA(zone, state, nil)
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case "TXT":
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records, err = k.TXT(zone, state)
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// TODO: change lookup to return appropriate error. Then add code below
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// this switch to check for the error and return not implemented.
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//return dns.RcodeNotImplemented, nil
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case "CNAME":
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records, err = k.CNAME(zone, state)
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case "MX":
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records, extra, err = k.MX(zone, state)
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case "SRV":
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records, extra, err = k.SRV(zone, state)
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case "SOA":
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records = []dns.RR{k.SOA(zone, state)}
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case "NS":
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if state.Name() == zone {
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records, extra, err = k.NS(zone, state)
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break
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}
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fallthrough
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default:
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// Do a fake A lookup, so we can distinguish between NODATA and NXDOMAIN
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_, err = k.A(zone, state, nil)
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}
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if isKubernetesNameError(err) {
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return k.Err(zone, dns.RcodeNameError, state)
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}
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if err != nil {
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return dns.RcodeServerFailure, err
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}
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if len(records) == 0 {
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return k.Err(zone, dns.RcodeSuccess, state)
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}
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m.Answer = append(m.Answer, records...)
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m.Extra = append(m.Extra, extra...)
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m = dnsutil.Dedup(m)
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state.SizeAndDo(m)
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m, _ = state.Scrub(m)
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w.WriteMsg(m)
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return dns.RcodeSuccess, nil
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}
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// Name implements the Handler interface.
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func (k Kubernetes) Name() string { return "kubernetes" }
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// Err writes an error response back to the client.
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func (k Kubernetes) Err(zone string, rcode int, state request.Request) (int, error) {
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m := new(dns.Msg)
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m.SetRcode(state.Req, rcode)
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m.Ns = []dns.RR{k.SOA(zone, state)}
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state.SizeAndDo(m)
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state.W.WriteMsg(m)
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return rcode, nil
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}
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