mirror of
https://github.com/coredns/coredns.git
synced 2025-10-30 17:53:21 -04:00
105 lines
2.8 KiB
Go
105 lines
2.8 KiB
Go
package cache
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import (
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"strings"
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"time"
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"github.com/coredns/coredns/plugin/cache/freq"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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)
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type item struct {
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Name string
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QType uint16
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Rcode int
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AuthenticatedData bool
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RecursionAvailable bool
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Answer []dns.RR
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Ns []dns.RR
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Extra []dns.RR
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origTTL uint32
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stored time.Time
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*freq.Freq
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}
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func newItem(m *dns.Msg, now time.Time, d time.Duration) *item {
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i := new(item)
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if len(m.Question) != 0 {
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i.Name = m.Question[0].Name
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i.QType = m.Question[0].Qtype
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}
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i.Rcode = m.Rcode
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i.AuthenticatedData = m.AuthenticatedData
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i.RecursionAvailable = m.RecursionAvailable
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i.Answer = m.Answer
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i.Ns = m.Ns
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i.Extra = make([]dns.RR, len(m.Extra))
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// Don't copy OPT records as these are hop-by-hop.
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j := 0
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for _, e := range m.Extra {
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if e.Header().Rrtype == dns.TypeOPT {
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continue
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}
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i.Extra[j] = e
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j++
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}
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i.Extra = i.Extra[:j]
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i.origTTL = uint32(d.Seconds())
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i.stored = now.UTC()
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i.Freq = new(freq.Freq)
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return i
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}
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// toMsg turns i into a message, it tailors the reply to m.
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// The Authoritative bit should be set to 0, but some client stub resolver implementations, most notably,
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// on some legacy systems(e.g. ubuntu 14.04 with glib version 2.20), low-level glibc function `getaddrinfo`
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// useb by Python/Ruby/etc.. will discard answers that do not have this bit set.
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// So we're forced to always set this to 1; regardless if the answer came from the cache or not.
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// On newer systems(e.g. ubuntu 16.04 with glib version 2.23), this issue is resolved.
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// So we may set this bit back to 0 in the future ?
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func (i *item) toMsg(m *dns.Msg, now time.Time, do bool) *dns.Msg {
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m1 := new(dns.Msg)
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m1.SetReply(m)
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// Set this to true as some DNS clients discard the *entire* packet when it's non-authoritative.
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// This is probably not according to spec, but the bit itself is not super useful as this point, so
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// just set it to true.
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m1.Authoritative = true
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m1.AuthenticatedData = i.AuthenticatedData
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if !do {
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m1.AuthenticatedData = false // when DNSSEC was not wanted, it can't be authenticated data.
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}
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m1.RecursionAvailable = i.RecursionAvailable
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m1.Rcode = i.Rcode
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m1.Answer = make([]dns.RR, len(i.Answer))
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m1.Ns = make([]dns.RR, len(i.Ns))
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m1.Extra = make([]dns.RR, len(i.Extra))
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ttl := uint32(i.ttl(now))
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m1.Answer = filterRRSlice(i.Answer, ttl, do, true)
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m1.Ns = filterRRSlice(i.Ns, ttl, do, true)
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m1.Extra = filterRRSlice(i.Extra, ttl, do, true)
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return m1
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}
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func (i *item) ttl(now time.Time) int {
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ttl := int(i.origTTL) - int(now.UTC().Sub(i.stored).Seconds())
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return ttl
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}
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func (i *item) matches(state request.Request) bool {
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if state.QType() == i.QType && strings.EqualFold(state.QName(), i.Name) {
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return true
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}
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return false
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}
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