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https://github.com/coredns/coredns.git
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5387c162c9
Full implementation, DNS (and in the future DNSSEC). Returns answer in a hopefully standards compliant way. Testing with my miek.nl zone are included as well. This should correctly handle nodata, nxdomain and cnames.
93 lines
2.1 KiB
Go
93 lines
2.1 KiB
Go
package etcd
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import (
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"github.com/miekg/coredns/middleware"
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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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func (e Etcd) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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state := middleware.State{W: w, Req: r}
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zone := middleware.Zones(e.Zones).Matches(state.Name())
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if zone == "" {
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return e.Next.ServeDNS(ctx, w, r)
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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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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 = e.A(zone, state, nil)
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case "AAAA":
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records, err = e.AAAA(zone, state, nil)
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case "TXT":
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records, err = e.TXT(zone, state)
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case "CNAME":
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records, err = e.CNAME(zone, state)
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case "MX":
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records, extra, err = e.MX(zone, state)
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case "SRV":
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records, extra, err = e.SRV(zone, state)
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default:
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// For SOA and NS we might still want this
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// and use dns.<zones> as the name to put these
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// also for stub
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// rwrite and return
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// Nodata response
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// also catch other types, so that they return NODATA
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// TODO(miek) nodata function see below
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return 0, nil
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}
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if isEtcdNameError(err) {
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m := new(dns.Msg)
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m.SetRcode(state.Req, dns.RcodeNameError)
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m.Ns = []dns.RR{e.SOA(zone, state)}
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state.W.WriteMsg(m)
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return dns.RcodeNameError, nil
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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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// NODATE function, see below
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m := new(dns.Msg)
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m.SetReply(state.Req)
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m.Ns = []dns.RR{e.SOA(zone, state)}
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state.W.WriteMsg(m)
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return dns.RcodeSuccess, nil
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}
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if len(records) > 0 {
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m.Answer = append(m.Answer, records...)
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}
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if len(extra) > 0 {
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m.Extra = append(m.Extra, extra...)
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}
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m = dedup(m)
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m, _ = state.Scrub(m)
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state.W.WriteMsg(m)
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return 0, nil
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}
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// NoData write a nodata response to the client.
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func (e Etcd) NoData(zone string, state middleware.State) {
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// TODO(miek): write it
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}
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func dedup(m *dns.Msg) *dns.Msg {
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ma := make(map[string]dns.RR)
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m.Answer = dns.Dedup(m.Answer, ma)
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m.Ns = dns.Dedup(m.Ns, ma)
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m.Extra = dns.Dedup(m.Extra, ma)
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return m
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}
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