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c4ab98c6e3
This checks if the next middleware to be called is nil, and if so returns ServerFailure and an error. This makes the next calling more robust and saves some lines of code. Also prefix the error with the name of the middleware to aid in debugging.
63 lines
1.6 KiB
Go
63 lines
1.6 KiB
Go
package file
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import (
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"fmt"
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"log"
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"github.com/miekg/coredns/middleware"
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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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// Xfr serves up an AXFR.
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type Xfr struct {
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*Zone
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}
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// ServeDNS implements the middleware.Handler interface.
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func (x Xfr) 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 !x.TransferAllowed(state) {
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return dns.RcodeServerFailure, nil
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}
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if state.QType() != dns.TypeAXFR && state.QType() != dns.TypeIXFR {
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return 0, middleware.Error(x.Name(), fmt.Errorf("xfr called with non transfer type: %d", state.QType()))
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}
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records := x.All()
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if len(records) == 0 {
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return dns.RcodeServerFailure, nil
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}
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ch := make(chan *dns.Envelope)
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defer close(ch)
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tr := new(dns.Transfer)
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go tr.Out(w, r, ch)
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j, l := 0, 0
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records = append(records, records[0]) // add closing SOA to the end
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log.Printf("[INFO] Outgoing transfer of %d records of zone %s to %s started", len(records), x.origin, state.IP())
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for i, r := range records {
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l += dns.Len(r)
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if l > transferLength {
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ch <- &dns.Envelope{RR: records[j:i]}
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l = 0
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j = i
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}
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}
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if j < len(records) {
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ch <- &dns.Envelope{RR: records[j:]}
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}
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w.Hijack()
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// w.Close() // Client closes connection
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return dns.RcodeSuccess, nil
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}
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// Name implements the middleware.Hander interface.
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func (x Xfr) Name() string { return "xfr" } // Or should we return "file" here?
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const transferLength = 1000 // Start a new envelop after message reaches this size in bytes. Intentionally small to test multi envelope parsing.
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