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cacheqtype.go
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cacheqtype.go
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package recursive
import (
"net/netip"
"sync"
"time"
"github.com/miekg/dns"
)
type cacheQtype struct {
mu sync.RWMutex
havewild bool // true if netip.Addr{} exists in keys
cache map[cacheKey]cacheValue
}
func (cq *cacheQtype) entries() (n int) {
cq.mu.RLock()
n = len(cq.cache)
cq.mu.RUnlock()
return
}
func (cq *cacheQtype) set(nsaddr netip.Addr, msg *dns.Msg, ttl int) {
ck := cacheKey{
nsaddr: nsaddr,
qname: msg.Question[0].Name,
}
cv := cacheValue{
Msg: msg,
expires: time.Now().Add(time.Duration(ttl) * time.Second),
}
cq.mu.Lock()
defer cq.mu.Unlock()
cq.havewild = cq.havewild || !ck.nsaddr.IsValid()
cq.cache[ck] = cv
}
func (cq *cacheQtype) get(nsaddr netip.Addr, qname string) (netip.Addr, *dns.Msg) {
ck := cacheKey{
nsaddr: nsaddr,
qname: qname,
}
cq.mu.RLock()
cv, ok := cq.cache[ck]
if !ok && cq.havewild {
ck.nsaddr = netip.Addr{}
cv, ok = cq.cache[ck]
}
cq.mu.RUnlock()
if ok {
if time.Since(cv.expires) < 0 {
return ck.nsaddr, cv.Msg
}
cq.mu.Lock()
if cv, ok := cq.cache[ck]; ok {
cq.deleteLocked(ck, cv)
}
cq.mu.Unlock()
}
return netip.Addr{}, nil
}
func (cq *cacheQtype) clear() {
cq.mu.Lock()
cq.havewild = false
clear(cq.cache)
cq.mu.Unlock()
}
func (cq *cacheQtype) clean(now time.Time) {
cq.mu.Lock()
defer cq.mu.Unlock()
havewild := false
for ck, cv := range cq.cache {
if now.After(cv.expires) {
cq.deleteLocked(ck, cv)
} else {
havewild = havewild || !ck.nsaddr.IsValid()
}
}
cq.havewild = havewild
}
func (cq *cacheQtype) deleteLocked(ck cacheKey, cv cacheValue) {
clear(cv.Msg.Question)
clear(cv.Msg.Answer)
clear(cv.Msg.Ns)
clear(cv.Msg.Extra)
delete(cq.cache, ck)
}