95 lines
3 KiB
Go
95 lines
3 KiB
Go
package kubernetes
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import (
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"errors"
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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, middleware.Error(k.Name(), errors.New("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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// 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 state.Type() != "PTR" {
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return middleware.NextOrFailure(k.Name(), k.Next, ctx, w, r)
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}
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// If this is a PTR request, and the request is in a defined
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// pod/service cidr range, process the request in this middleware,
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// otherwise pass to next middleware.
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if !k.IsRequestInReverseRange(state) {
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return middleware.NextOrFailure(k.Name(), k.Next, ctx, w, r)
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}
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// Set the zone to this specific request.
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zone = state.Name()
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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 = middleware.A(&k, zone, state, nil, middleware.Options{}) // Hmm wrt to '&k'
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case "AAAA":
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records, _, err = middleware.AAAA(&k, zone, state, nil, middleware.Options{})
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case "TXT":
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records, _, err = middleware.TXT(&k, zone, state, middleware.Options{})
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case "CNAME":
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records, _, err = middleware.CNAME(&k, zone, state, middleware.Options{})
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case "PTR":
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records, _, err = middleware.PTR(&k, zone, state, middleware.Options{})
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case "MX":
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records, extra, _, err = middleware.MX(&k, zone, state, middleware.Options{})
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case "SRV":
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records, extra, _, err = middleware.SRV(&k, zone, state, middleware.Options{})
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case "SOA":
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records, _, err = middleware.SOA(&k, zone, state, middleware.Options{})
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case "NS":
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if state.Name() == zone {
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records, extra, _, err = middleware.NS(&k, zone, state, middleware.Options{})
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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 = middleware.A(&k, zone, state, nil, middleware.Options{})
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}
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if k.IsNameError(err) {
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return middleware.BackendError(&k, zone, dns.RcodeNameError, state, nil /*debug*/, err, middleware.Options{})
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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 middleware.BackendError(&k, zone, dns.RcodeSuccess, state, nil /*debug*/, nil, middleware.Options{})
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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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