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package cache
import (
"github.com/miekg/coredns/middleware"
"github.com/miekg/dns"
"golang.org/x/net/context"
)
// ServeDNS implements the middleware.Handler interface.
func (c Cache) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
state := middleware.State{W: w, Req: r}
qname := state.Name()
qtype := state.QType()
zone := middleware.Zones(c.Zones).Matches(qname)
if zone == "" {
return c.Next.ServeDNS(ctx, w, r)
}
do := state.Do() // might need more from OPT record?
if i, ok := c.Get(qname, qtype, do); ok {
resp := i.toMsg(r)
state.SizeAndDo(resp)
w.WriteMsg(resp)
return dns.RcodeSuccess, nil
}
crr := NewCachingResponseWriter(w, c.cache, c.cap)
return c.Next.ServeDNS(ctx, crr, r)
}
func (c Cache) Get(qname string, qtype uint16, do bool) (*item, bool) {
nxdomain := nameErrorKey(qname, do)
if i, ok := c.cache.Get(nxdomain); ok {
return i.(*item), true
}
successOrNoData := successKey(qname, qtype, do)
if i, ok := c.cache.Get(successOrNoData); ok {
return i.(*item), true
}
return nil, false
}
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