115 lines
2.5 KiB
Go
115 lines
2.5 KiB
Go
package cache
|
|
|
|
import (
|
|
"time"
|
|
|
|
"github.com/miekg/coredns/middleware/pkg/response"
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
type item struct {
|
|
Rcode int
|
|
Authoritative bool
|
|
AuthenticatedData bool
|
|
RecursionAvailable bool
|
|
Answer []dns.RR
|
|
Ns []dns.RR
|
|
Extra []dns.RR
|
|
|
|
origTTL uint32
|
|
stored time.Time
|
|
}
|
|
|
|
func newItem(m *dns.Msg, d time.Duration) *item {
|
|
i := new(item)
|
|
i.Rcode = m.Rcode
|
|
i.Authoritative = m.Authoritative
|
|
i.AuthenticatedData = m.AuthenticatedData
|
|
i.RecursionAvailable = m.RecursionAvailable
|
|
i.Answer = m.Answer
|
|
i.Ns = m.Ns
|
|
i.Extra = make([]dns.RR, len(m.Extra))
|
|
// Don't copy OPT record as these are hop-by-hop.
|
|
j := 0
|
|
for _, e := range m.Extra {
|
|
if e.Header().Rrtype == dns.TypeOPT {
|
|
continue
|
|
}
|
|
i.Extra[j] = e
|
|
j++
|
|
}
|
|
i.Extra = i.Extra[:j]
|
|
|
|
i.origTTL = uint32(d.Seconds())
|
|
i.stored = time.Now().UTC()
|
|
|
|
return i
|
|
}
|
|
|
|
// toMsg turns i into a message, it tailers the reply to m.
|
|
// The Authoritative bit is always set to 0, because the answer is from the cache.
|
|
func (i *item) toMsg(m *dns.Msg) *dns.Msg {
|
|
m1 := new(dns.Msg)
|
|
m1.SetReply(m)
|
|
|
|
m1.Authoritative = false
|
|
m1.AuthenticatedData = i.AuthenticatedData
|
|
m1.RecursionAvailable = i.RecursionAvailable
|
|
m1.Rcode = i.Rcode
|
|
m1.Compress = true
|
|
|
|
m1.Answer = i.Answer
|
|
m1.Ns = i.Ns
|
|
m1.Extra = i.Extra
|
|
|
|
ttl := int(i.origTTL) - int(time.Now().UTC().Sub(i.stored).Seconds())
|
|
setMsgTTL(m1, uint32(ttl))
|
|
return m1
|
|
}
|
|
|
|
func (i *item) expired(now time.Time) bool {
|
|
ttl := int(i.origTTL) - int(now.UTC().Sub(i.stored).Seconds())
|
|
return ttl < 0
|
|
}
|
|
|
|
// setMsgTTL sets the ttl on all RRs in all sections. If ttl is smaller than minTTL
|
|
// that value is used.
|
|
func setMsgTTL(m *dns.Msg, ttl uint32) {
|
|
if ttl < minTTL {
|
|
ttl = minTTL
|
|
}
|
|
|
|
for _, r := range m.Answer {
|
|
r.Header().Ttl = ttl
|
|
}
|
|
for _, r := range m.Ns {
|
|
r.Header().Ttl = ttl
|
|
}
|
|
for _, r := range m.Extra {
|
|
if r.Header().Rrtype == dns.TypeOPT {
|
|
continue
|
|
}
|
|
r.Header().Ttl = ttl
|
|
}
|
|
}
|
|
|
|
func minMsgTTL(m *dns.Msg, mt response.Type) time.Duration {
|
|
if mt != response.NoError && mt != response.NameError && mt != response.NoData {
|
|
return 0
|
|
}
|
|
|
|
minTTL := maxTTL
|
|
for _, r := range append(m.Answer, m.Ns...) {
|
|
switch mt {
|
|
case response.NameError, response.NoData:
|
|
if r.Header().Rrtype == dns.TypeSOA {
|
|
return time.Duration(r.(*dns.SOA).Minttl) * time.Second
|
|
}
|
|
case response.NoError, response.Delegation:
|
|
if r.Header().Ttl < uint32(minTTL.Seconds()) {
|
|
minTTL = time.Duration(r.Header().Ttl) * time.Second
|
|
}
|
|
}
|
|
}
|
|
return minTTL
|
|
}
|