miracle091/dnscrypt-proxy
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dnscrypt-proxy
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Set a minimum TTL when caching resolver IPs 

Comcast having a 30 sec TTL is silly
This commit is contained in:
Frank Denis 2019-11-02 02:01:03 +01:00
parent 63ed3b4fef
commit 0f332c644d
1 changed files with 11 additions and 7 deletions
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18
dnscrypt-proxy/xtransport.go
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@ -29,8 +29,9 @@ const (
DefaultFallbackResolver = "9.9.9.9:53"
DefaultKeepAlive = 5 * time.Second
DefaultTimeout = 30 * time.Second
SystemResolverTTL = 24 * time.Hour
ExpiredCachedIPGraceTTL = 1 * time.Minute
SystemRresolverIPTTL = 24 * time.Hour
MinRresolverIPTTL = 8 * time.Hour
ExpiredCachedIPGraceTTL = 5 * time.Minute
)
type CachedIPItem struct {
@ -83,12 +84,12 @@ func ParseIP(ipStr string) net.IP {
}
// If ttl < 0, never expire
// Otherwise, ttl is set to max(ttl, SystemResolverTTL)
// Otherwise, ttl is set to max(ttl, MinRresolverIPTTL)
func (xTransport *XTransport) saveCachedIP(host string, ip net.IP, ttl time.Duration) {
item := &CachedIPItem{ip: ip, expiration: nil}
if ttl >= 0 {
if ttl < SystemResolverTTL {
ttl = SystemResolverTTL
if ttl < MinRresolverIPTTL {
ttl = MinRresolverIPTTL
}
expiration := time.Now().Add(ttl)
item.expiration = &expiration
@ -172,7 +173,7 @@ func (xTransport *XTransport) rebuildTransport() {
}
func (xTransport *XTransport) resolveUsingSystem(host string) (ip net.IP, ttl time.Duration, err error) {
ttl = SystemResolverTTL
ttl = SystemRresolverIPTTL
var foundIPs []string
foundIPs, err = net.LookupHost(host)
if err != nil {
@ -278,6 +279,9 @@ func (xTransport *XTransport) resolveWithCache(host string) (err error) {
}
}
}
if ttl < MinRresolverIPTTL {
ttl = MinRresolverIPTTL
}
if err != nil {
if cachedIP != nil {
foundIP = cachedIP
@ -287,7 +291,7 @@ func (xTransport *XTransport) resolveWithCache(host string) (err error) {
}
}
xTransport.saveCachedIP(host, foundIP, ttl)
dlog.Debugf("[%s] IP address [%s] added to the cache, valid until %v", host, foundIP, ttl)
dlog.Debugf("[%s] IP address [%s] added to the cache, valid for %v", host, foundIP, ttl)
return
}