d35394a8df
When setting the TTL on all RR in the message we would also do this for the OPT RR. This is wrong as the OPT RR does *not* have a TTL.
101 lines
2.2 KiB
Go
101 lines
2.2 KiB
Go
package cache
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import (
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"strconv"
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"time"
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"github.com/miekg/dns"
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)
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type item struct {
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Authoritative bool
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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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}
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func newItem(m *dns.Msg, d time.Duration) *item {
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i := new(item)
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i.Authoritative = m.Authoritative
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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 record 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 = time.Now().UTC()
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return i
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}
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// toMsg turns i into a message, it tailers to reply to m.
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func (i *item) toMsg(m *dns.Msg) *dns.Msg {
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m1 := new(dns.Msg)
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m1.SetReply(m)
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m1.Authoritative = i.Authoritative
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m1.AuthenticatedData = i.AuthenticatedData
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m1.RecursionAvailable = i.RecursionAvailable
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m1.Compress = true
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m1.Answer = i.Answer
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m1.Ns = i.Ns
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m1.Extra = i.Extra
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ttl := int(i.origTtl) - int(time.Now().UTC().Sub(i.stored).Seconds())
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if ttl < baseTtl {
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ttl = baseTtl
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}
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setCap(m1, uint32(ttl))
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return m1
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}
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// setCap sets the ttl on all RRs in all sections.
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func setCap(m *dns.Msg, ttl uint32) {
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for _, r := range m.Answer {
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r.Header().Ttl = uint32(ttl)
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}
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for _, r := range m.Ns {
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r.Header().Ttl = uint32(ttl)
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}
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for _, r := range m.Extra {
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if r.Header().Rrtype == dns.TypeOPT {
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continue
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}
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r.Header().Ttl = uint32(ttl)
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}
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}
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// nodataKey returns a caching key for NODATA responses.
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func noDataKey(qname string, qtype uint16, do bool) string {
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if do {
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return "1" + qname + ".." + strconv.Itoa(int(qtype))
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}
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return "0" + qname + ".." + strconv.Itoa(int(qtype))
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}
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// nameErrorKey returns a caching key for NXDOMAIN responses.
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func nameErrorKey(qname string, do bool) string {
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if do {
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return "1" + qname
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}
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return "0" + qname
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}
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// successKey returns a caching key for successfull answers.
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func successKey(qname string, qtype uint16, do bool) string { return noDataKey(qname, qtype, do) }
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