165 lines
3.4 KiB
Go
165 lines
3.4 KiB
Go
package main
|
|
|
|
import (
|
|
"crypto/sha512"
|
|
"encoding/binary"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/miekg/dns"
|
|
sieve "github.com/opencoff/go-sieve"
|
|
)
|
|
|
|
const StaleResponseTTL = 30 * time.Second
|
|
|
|
type CachedResponse struct {
|
|
expiration time.Time
|
|
msg dns.Msg
|
|
}
|
|
|
|
type CachedResponses struct {
|
|
sync.RWMutex
|
|
cache *sieve.Sieve[[32]byte, CachedResponse]
|
|
}
|
|
|
|
var cachedResponses CachedResponses
|
|
|
|
func computeCacheKey(pluginsState *PluginsState, msg *dns.Msg) [32]byte {
|
|
question := msg.Question[0]
|
|
h := sha512.New512_256()
|
|
var tmp [5]byte
|
|
binary.LittleEndian.PutUint16(tmp[0:2], question.Qtype)
|
|
binary.LittleEndian.PutUint16(tmp[2:4], question.Qclass)
|
|
if pluginsState.dnssec {
|
|
tmp[4] = 1
|
|
}
|
|
h.Write(tmp[:])
|
|
normalizedRawQName := []byte(question.Name)
|
|
NormalizeRawQName(&normalizedRawQName)
|
|
h.Write(normalizedRawQName)
|
|
var sum [32]byte
|
|
h.Sum(sum[:0])
|
|
|
|
return sum
|
|
}
|
|
|
|
// ---
|
|
|
|
type PluginCache struct{}
|
|
|
|
func (plugin *PluginCache) Name() string {
|
|
return "cache"
|
|
}
|
|
|
|
func (plugin *PluginCache) Description() string {
|
|
return "DNS cache (reader)."
|
|
}
|
|
|
|
func (plugin *PluginCache) Init(proxy *Proxy) error {
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginCache) Drop() error {
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginCache) Reload() error {
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginCache) Eval(pluginsState *PluginsState, msg *dns.Msg) error {
|
|
cacheKey := computeCacheKey(pluginsState, msg)
|
|
|
|
cachedResponses.RLock()
|
|
if cachedResponses.cache == nil {
|
|
cachedResponses.RUnlock()
|
|
return nil
|
|
}
|
|
cached, ok := cachedResponses.cache.Get(cacheKey)
|
|
if !ok {
|
|
cachedResponses.RUnlock()
|
|
return nil
|
|
}
|
|
expiration := cached.expiration
|
|
synth := cached.msg.Copy()
|
|
cachedResponses.RUnlock()
|
|
|
|
synth.Id = msg.Id
|
|
synth.Response = true
|
|
synth.Compress = true
|
|
synth.Question = msg.Question
|
|
|
|
if time.Now().After(expiration) {
|
|
expiration2 := time.Now().Add(StaleResponseTTL)
|
|
updateTTL(synth, expiration2)
|
|
pluginsState.sessionData["stale"] = synth
|
|
return nil
|
|
}
|
|
|
|
updateTTL(synth, expiration)
|
|
|
|
pluginsState.synthResponse = synth
|
|
pluginsState.action = PluginsActionSynth
|
|
pluginsState.cacheHit = true
|
|
return nil
|
|
}
|
|
|
|
// ---
|
|
|
|
type PluginCacheResponse struct{}
|
|
|
|
func (plugin *PluginCacheResponse) Name() string {
|
|
return "cache_response"
|
|
}
|
|
|
|
func (plugin *PluginCacheResponse) Description() string {
|
|
return "DNS cache (writer)."
|
|
}
|
|
|
|
func (plugin *PluginCacheResponse) Init(proxy *Proxy) error {
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginCacheResponse) Drop() error {
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginCacheResponse) Reload() error {
|
|
return nil
|
|
}
|
|
|
|
func (plugin *PluginCacheResponse) Eval(pluginsState *PluginsState, msg *dns.Msg) error {
|
|
if msg.Rcode != dns.RcodeSuccess && msg.Rcode != dns.RcodeNameError && msg.Rcode != dns.RcodeNotAuth {
|
|
return nil
|
|
}
|
|
if msg.Truncated {
|
|
return nil
|
|
}
|
|
cacheKey := computeCacheKey(pluginsState, msg)
|
|
ttl := getMinTTL(
|
|
msg,
|
|
pluginsState.cacheMinTTL,
|
|
pluginsState.cacheMaxTTL,
|
|
pluginsState.cacheNegMinTTL,
|
|
pluginsState.cacheNegMaxTTL,
|
|
)
|
|
cachedResponse := CachedResponse{
|
|
expiration: time.Now().Add(ttl),
|
|
msg: *msg,
|
|
}
|
|
cachedResponses.Lock()
|
|
if cachedResponses.cache == nil {
|
|
var err error
|
|
cachedResponses.cache = sieve.New[[32]byte, CachedResponse](pluginsState.cacheSize)
|
|
if cachedResponses.cache == nil {
|
|
cachedResponses.Unlock()
|
|
return err
|
|
}
|
|
}
|
|
cachedResponses.cache.Add(cacheKey, cachedResponse)
|
|
cachedResponses.Unlock()
|
|
updateTTL(msg, cachedResponse.expiration)
|
|
|
|
return nil
|
|
}
|