Add rejected DNS response cache support

experimental/cachefile/cache.go

@@ -29,6 +29,7 @@ var (
 		string(bucketExpand),
 		string(bucketMode),
 		string(bucketRuleSet),
+		string(bucketRDRC),
 	}
 
 	cacheIDDefault = []byte("default")
@@ -37,17 +38,25 @@ var (
 var _ adapter.CacheFile = (*CacheFile)(nil)
 
 type CacheFile struct {
-	ctx         context.Context
-	path        string
-	cacheID     []byte
-	storeFakeIP bool
-
+	ctx               context.Context
+	path              string
+	cacheID           []byte
+	storeFakeIP       bool
+	storeRDRC         bool
+	rdrcTimeout       time.Duration
 	DB                *bbolt.DB
-	saveAccess        sync.RWMutex
+	saveMetadataTimer *time.Timer
+	saveFakeIPAccess  sync.RWMutex
 	saveDomain        map[netip.Addr]string
 	saveAddress4      map[string]netip.Addr
 	saveAddress6      map[string]netip.Addr
-	saveMetadataTimer *time.Timer
+	saveRDRCAccess    sync.RWMutex
+	saveRDRC          map[saveRDRCCacheKey]bool
+}
+
+type saveRDRCCacheKey struct {
+	TransportName string
+	QuestionName  string
 }
 
 func New(ctx context.Context, options option.CacheFileOptions) *CacheFile {
@@ -61,14 +70,25 @@ func New(ctx context.Context, options option.CacheFileOptions) *CacheFile {
 	if options.CacheID != "" {
 		cacheIDBytes = append([]byte{0}, []byte(options.CacheID)...)
 	}
+	var rdrcTimeout time.Duration
+	if options.StoreRDRC {
+		if options.RDRCTimeout > 0 {
+			rdrcTimeout = time.Duration(options.RDRCTimeout)
+		} else {
+			rdrcTimeout = 7 * 24 * time.Hour
+		}
+	}
 	return &CacheFile{
 		ctx:          ctx,
 		path:         filemanager.BasePath(ctx, path),
 		cacheID:      cacheIDBytes,
 		storeFakeIP:  options.StoreFakeIP,
+		storeRDRC:    options.StoreRDRC,
+		rdrcTimeout:  rdrcTimeout,
 		saveDomain:   make(map[netip.Addr]string),
 		saveAddress4: make(map[string]netip.Addr),
 		saveAddress6: make(map[string]netip.Addr),
+		saveRDRC:     make(map[saveRDRCCacheKey]bool),
 	}
 }
 

experimental/cachefile/fakeip.go

@@ -89,34 +89,34 @@ func (c *CacheFile) FakeIPStore(address netip.Addr, domain string) error {
 }
 
 func (c *CacheFile) FakeIPStoreAsync(address netip.Addr, domain string, logger logger.Logger) {
-	c.saveAccess.Lock()
+	c.saveFakeIPAccess.Lock()
 	c.saveDomain[address] = domain
 	if address.Is4() {
 		c.saveAddress4[domain] = address
 	} else {
 		c.saveAddress6[domain] = address
 	}
-	c.saveAccess.Unlock()
+	c.saveFakeIPAccess.Unlock()
 	go func() {
 		err := c.FakeIPStore(address, domain)
 		if err != nil {
-			logger.Warn("save FakeIP address pair: ", err)
+			logger.Warn("save FakeIP cache: ", err)
 		}
-		c.saveAccess.Lock()
+		c.saveFakeIPAccess.Lock()
 		delete(c.saveDomain, address)
 		if address.Is4() {
 			delete(c.saveAddress4, domain)
 		} else {
 			delete(c.saveAddress6, domain)
 		}
-		c.saveAccess.Unlock()
+		c.saveFakeIPAccess.Unlock()
 	}()
 }
 
 func (c *CacheFile) FakeIPLoad(address netip.Addr) (string, bool) {
-	c.saveAccess.RLock()
+	c.saveFakeIPAccess.RLock()
 	cachedDomain, cached := c.saveDomain[address]
-	c.saveAccess.RUnlock()
+	c.saveFakeIPAccess.RUnlock()
 	if cached {
 		return cachedDomain, true
 	}
@@ -137,13 +137,13 @@ func (c *CacheFile) FakeIPLoadDomain(domain string, isIPv6 bool) (netip.Addr, bo
 		cachedAddress netip.Addr
 		cached        bool
 	)
-	c.saveAccess.RLock()
+	c.saveFakeIPAccess.RLock()
 	if !isIPv6 {
 		cachedAddress, cached = c.saveAddress4[domain]
 	} else {
 		cachedAddress, cached = c.saveAddress6[domain]
 	}
-	c.saveAccess.RUnlock()
+	c.saveFakeIPAccess.RUnlock()
 	if cached {
 		return cachedAddress, true
 	}

experimental/cachefile/rdrc.go

@@ -0,0 +1,101 @@
+package cachefile
+
+import (
+	"encoding/binary"
+	"time"
+
+	"github.com/sagernet/bbolt"
+	"github.com/sagernet/sing/common/buf"
+	"github.com/sagernet/sing/common/logger"
+)
+
+var bucketRDRC = []byte("rdrc")
+
+func (c *CacheFile) StoreRDRC() bool {
+	return c.storeRDRC
+}
+
+func (c *CacheFile) RDRCTimeout() time.Duration {
+	return c.rdrcTimeout
+}
+
+func (c *CacheFile) LoadRDRC(transportName string, qName string) (rejected bool) {
+	c.saveRDRCAccess.RLock()
+	rejected, cached := c.saveRDRC[saveRDRCCacheKey{transportName, qName}]
+	c.saveRDRCAccess.RUnlock()
+	if cached {
+		return
+	}
+	var deleteCache bool
+	err := c.DB.View(func(tx *bbolt.Tx) error {
+		bucket := c.bucket(tx, bucketRDRC)
+		if bucket == nil {
+			return nil
+		}
+		bucket = bucket.Bucket([]byte(transportName))
+		if bucket == nil {
+			return nil
+		}
+		content := bucket.Get([]byte(qName))
+		if content == nil {
+			return nil
+		}
+		expiresAt := time.Unix(int64(binary.BigEndian.Uint64(content)), 0)
+		if time.Now().After(expiresAt) {
+			deleteCache = true
+			return nil
+		}
+		rejected = true
+		return nil
+	})
+	if err != nil {
+		return
+	}
+	if deleteCache {
+		c.DB.Update(func(tx *bbolt.Tx) error {
+			bucket := c.bucket(tx, bucketRDRC)
+			if bucket == nil {
+				return nil
+			}
+			bucket = bucket.Bucket([]byte(transportName))
+			if bucket == nil {
+				return nil
+			}
+			return bucket.Delete([]byte(qName))
+		})
+	}
+	return
+}
+
+func (c *CacheFile) SaveRDRC(transportName string, qName string) error {
+	return c.DB.Batch(func(tx *bbolt.Tx) error {
+		bucket, err := c.createBucket(tx, bucketRDRC)
+		if err != nil {
+			return err
+		}
+		bucket, err = bucket.CreateBucketIfNotExists([]byte(transportName))
+		if err != nil {
+			return err
+		}
+		expiresAt := buf.Get(8)
+		defer buf.Put(expiresAt)
+		binary.BigEndian.PutUint64(expiresAt, uint64(time.Now().Add(c.rdrcTimeout).Unix()))
+		return bucket.Put([]byte(qName), expiresAt)
+	})
+}
+
+func (c *CacheFile) SaveRDRCAsync(transportName string, qName string, logger logger.Logger) {
+	saveKey := saveRDRCCacheKey{transportName, qName}
+	c.saveRDRCAccess.Lock()
+	c.saveRDRC[saveKey] = true
+	c.saveRDRCAccess.Unlock()
+	go func() {
+		err := c.SaveRDRC(transportName, qName)
+		if err != nil {
+			logger.Warn("save RDRC: ", err)
+		}
+		c.saveRDRCAccess.Lock()
+		delete(c.saveRDRC, saveKey)
+		c.saveRDRCAccess.Unlock()
+	}()
+}