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https://github.com/coredns/coredns.git
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d8714e64e4
* Rename middleware to plugin first pass; mostly used 'sed', few spots where I manually changed text. This still builds a coredns binary. * fmt error * Rename AddMiddleware to AddPlugin * Readd AddMiddleware to remain backwards compat
83 lines
2.2 KiB
Go
83 lines
2.2 KiB
Go
package etcd
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import (
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"log"
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"net"
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"strconv"
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"time"
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"github.com/coredns/coredns/plugin/etcd/msg"
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"github.com/coredns/coredns/plugin/pkg/dnsutil"
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"github.com/coredns/coredns/plugin/proxy"
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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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// UpdateStubZones checks etcd for an update on the stubzones.
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func (e *Etcd) UpdateStubZones() {
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go func() {
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for {
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e.updateStubZones()
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time.Sleep(15 * time.Second)
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}
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}()
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}
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// Look in .../dns/stub/<zone>/xx for msg.Services. Loop through them
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// extract <zone> and add them as forwarders (ip:port-combos) for
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// the stub zones. Only numeric (i.e. IP address) hosts are used.
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// Only the first zone configured on e is used for the lookup.
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func (e *Etcd) updateStubZones() {
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zone := e.Zones[0]
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fakeState := request.Request{W: nil, Req: new(dns.Msg)}
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fakeState.Req.SetQuestion(stubDomain+"."+zone, dns.TypeA)
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services, err := e.Records(fakeState, false)
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if err != nil {
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return
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}
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stubmap := make(map[string]proxy.Proxy)
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// track the nameservers on a per domain basis, but allow a list on the domain.
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nameservers := map[string][]string{}
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Services:
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for _, serv := range services {
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if serv.Port == 0 {
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serv.Port = 53
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}
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ip := net.ParseIP(serv.Host)
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if ip == nil {
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log.Printf("[WARNING] Non IP address stub nameserver: %s", serv.Host)
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continue
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}
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domain := msg.Domain(serv.Key)
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labels := dns.SplitDomainName(domain)
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// If the remaining name equals any of the zones we have, we ignore it.
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for _, z := range e.Zones {
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// Chop of left most label, because that is used as the nameserver place holder
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// and drop the right most labels that belong to zone.
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// We must *also* chop of dns.stub. which means cutting two more labels.
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domain = dnsutil.Join(labels[1 : len(labels)-dns.CountLabel(z)-2])
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if domain == z {
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log.Printf("[WARNING] Skipping nameserver for domain we are authoritative for: %s", domain)
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continue Services
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}
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}
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nameservers[domain] = append(nameservers[domain], net.JoinHostPort(serv.Host, strconv.Itoa(serv.Port)))
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}
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for domain, nss := range nameservers {
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stubmap[domain] = proxy.NewLookup(nss)
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}
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// atomic swap (at least that's what we hope it is)
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if len(stubmap) > 0 {
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e.Stubmap = &stubmap
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}
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return
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}
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