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e54c232c8c
Make the cache memory bounded, by using a LRU cache. Also split the
cache in a positive and negative one - each with its own controls.
Extend the cache stanza to allow for this:
cache {
positive limit [ttl]
negative limit [ttl]
}
is now possible. This also add a cache_test.go in the toplevel test/
directory that exercises the caching path.
Fixes #260
75 lines
1.5 KiB
Go
75 lines
1.5 KiB
Go
package response
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import "github.com/miekg/dns"
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// Type is the type of the message
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type Type int
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const (
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// Success indicates a positive reply
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Success Type = iota
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// NameError is a NXDOMAIN in header, SOA in auth.
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NameError
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// NoData indicated name found, but not the type: NOERROR in header, SOA in auth.
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NoData
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// Delegation is a msg with a pointer to another nameserver: NOERROR in header, NS in auth, optionally fluff in additional (not checked).
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Delegation
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// OtherError indicated any other error: don't cache these.
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OtherError
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)
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func (t Type) String() string {
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switch t {
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case Success:
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return "NOERROR"
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case NameError:
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return "NXDOMAIN"
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case NoData:
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return "NODATA"
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case Delegation:
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return "DELEGATION"
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case OtherError:
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return "OTHERERROR"
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}
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return ""
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}
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// Classify classifies a message, it returns the Type.
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func Classify(m *dns.Msg) (Type, *dns.OPT) {
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opt := m.IsEdns0()
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if len(m.Answer) > 0 && m.Rcode == dns.RcodeSuccess {
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return Success, opt
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}
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soa := false
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ns := 0
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for _, r := range m.Ns {
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if r.Header().Rrtype == dns.TypeSOA {
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soa = true
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continue
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}
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if r.Header().Rrtype == dns.TypeNS {
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ns++
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}
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}
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// Check length of different sections, and drop stuff that is just to large? TODO(miek).
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if soa && m.Rcode == dns.RcodeSuccess {
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return NoData, opt
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}
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if soa && m.Rcode == dns.RcodeNameError {
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return NameError, opt
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}
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if ns > 0 && ns == len(m.Ns) && m.Rcode == dns.RcodeSuccess {
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return Delegation, opt
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}
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if m.Rcode == dns.RcodeSuccess {
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return Success, opt
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}
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return OtherError, opt
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}
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