39 lines
1009 B
Go
39 lines
1009 B
Go
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package tunneldns
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import (
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"github.com/coredns/coredns/plugin"
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"github.com/miekg/dns"
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"github.com/pkg/errors"
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"golang.org/x/net/context"
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)
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// Upstream is a simplified interface for proxy destination
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type Upstream interface {
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Exchange(ctx context.Context, query *dns.Msg) (*dns.Msg, error)
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}
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// ProxyPlugin is a simplified DNS proxy using a generic upstream interface
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type ProxyPlugin struct {
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Upstreams []Upstream
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Next plugin.Handler
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}
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// ServeDNS implements interface for CoreDNS plugin
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func (p ProxyPlugin) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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var reply *dns.Msg
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var backendErr error
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for _, upstream := range p.Upstreams {
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reply, backendErr = upstream.Exchange(ctx, r)
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if backendErr == nil {
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w.WriteMsg(reply)
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return 0, nil
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}
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}
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return dns.RcodeServerFailure, errors.Wrap(backendErr, "failed to contact any of the upstreams")
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}
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// Name implements interface for CoreDNS plugin
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func (p ProxyPlugin) Name() string { return "proxy" }
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