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
74 lines
1.5 KiB
Go
74 lines
1.5 KiB
Go
package response
|
|
|
|
import "github.com/miekg/dns"
|
|
|
|
// Type is the type of the message
|
|
type Type int
|
|
|
|
const (
|
|
// Success indicates a positive reply
|
|
Success Type = iota
|
|
// NameError is a NXDOMAIN in header, SOA in auth.
|
|
NameError
|
|
// NoData indicated name found, but not the type: NOERROR in header, SOA in auth.
|
|
NoData
|
|
// Delegation is a msg with a pointer to another nameserver: NOERROR in header, NS in auth, optionally fluff in additional (not checked).
|
|
Delegation
|
|
// OtherError indicated any other error: don't cache these.
|
|
OtherError
|
|
)
|
|
|
|
func (t Type) String() string {
|
|
switch t {
|
|
case Success:
|
|
return "NOERROR"
|
|
case NameError:
|
|
return "NXDOMAIN"
|
|
case NoData:
|
|
return "NODATA"
|
|
case Delegation:
|
|
return "DELEGATION"
|
|
case OtherError:
|
|
return "OTHERERROR"
|
|
}
|
|
return ""
|
|
}
|
|
|
|
// Classify classifies a message, it returns the Type.
|
|
func Classify(m *dns.Msg) (Type, *dns.OPT) {
|
|
opt := m.IsEdns0()
|
|
|
|
if len(m.Answer) > 0 && m.Rcode == dns.RcodeSuccess {
|
|
return Success, opt
|
|
}
|
|
|
|
soa := false
|
|
ns := 0
|
|
for _, r := range m.Ns {
|
|
if r.Header().Rrtype == dns.TypeSOA {
|
|
soa = true
|
|
continue
|
|
}
|
|
if r.Header().Rrtype == dns.TypeNS {
|
|
ns++
|
|
}
|
|
}
|
|
|
|
// Check length of different sections, and drop stuff that is just to large? TODO(miek).
|
|
if soa && m.Rcode == dns.RcodeSuccess {
|
|
return NoData, opt
|
|
}
|
|
if soa && m.Rcode == dns.RcodeNameError {
|
|
return NameError, opt
|
|
}
|
|
|
|
if ns > 0 && ns == len(m.Ns) && m.Rcode == dns.RcodeSuccess {
|
|
return Delegation, opt
|
|
}
|
|
|
|
if m.Rcode == dns.RcodeSuccess {
|
|
return Success, opt
|
|
}
|
|
|
|
return OtherError, opt
|
|
}
|