71ee323651
* add upstream @self and loop count * 1st round of feedback * allow argless upstream * update test * readmes * feedback
55 lines
1.4 KiB
Go
55 lines
1.4 KiB
Go
// Package upstream abstracts a upstream lookups so that plugins
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// can handle them in an unified way.
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package upstream
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import (
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"github.com/miekg/dns"
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/plugin/pkg/dnsutil"
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"github.com/coredns/coredns/plugin/pkg/nonwriter"
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"github.com/coredns/coredns/plugin/proxy"
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"github.com/coredns/coredns/request"
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)
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// Upstream is used to resolve CNAME targets
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type Upstream struct {
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self bool
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Forward *proxy.Proxy
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}
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// NewUpstream creates a new Upstream for given destination(s)
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func NewUpstream(dests []string) (Upstream, error) {
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u := Upstream{}
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if len(dests) == 0 {
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u.self = true
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return u, nil
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}
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u.self = false
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ups, err := dnsutil.ParseHostPortOrFile(dests...)
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if err != nil {
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return u, err
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}
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p := proxy.NewLookup(ups)
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u.Forward = &p
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return u, nil
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}
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// Lookup routes lookups to Self or Forward
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func (u Upstream) Lookup(state request.Request, name string, typ uint16) (*dns.Msg, error) {
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if u.self {
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// lookup via self
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req := new(dns.Msg)
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req.SetQuestion(name, typ)
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state.SizeAndDo(req)
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nw := nonwriter.New(state.W)
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state2 := request.Request{W: nw, Req: req}
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server := state.Context.Value(dnsserver.Key{}).(*dnsserver.Server)
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server.ServeDNS(state.Context, state2.W, req)
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return nw.Msg, nil
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}
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if u.Forward != nil {
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return u.Forward.Lookup(state, name, typ)
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}
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return &dns.Msg{}, nil
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}
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