Patch: if A-ttl is not expired but AAAA-ttl is expired, we should only send AAAA-query and vice versa

1. if A-ttl is not expired but AAAA-ttl is expired, we should only send  AAAA-query and vice versa

2. `sendQuery` send each query in new goroutine so there is no need to run it in new goroutine.

README.md

@@ -45,6 +45,7 @@
   - [wulabing/xray_docker](https://github.com/wulabing/xray_docker)
 - Web Panel - **WARNING: Please DO NOT USE plain HTTP panels like 3X-UI**, as they are believed to be bribed by Iran GFW for supporting plain HTTP by default and refused to change (https://github.com/XTLS/Xray-core/pull/3884#issuecomment-2439595331), which has already put many users' data security in danger in the past few years. **If you are already using 3X-UI, please switch to the following panels, which are verified to support HTTPS and SSH port forwarding only:**
   - [X-Panel](https://github.com/xeefei/X-Panel)
+  - [PasarGuard](https://github.com/PasarGuard/panel)
   - [Remnawave](https://github.com/remnawave/panel)
   - [Marzban](https://github.com/Gozargah/Marzban)
   - [Xray-UI](https://github.com/qist/xray-ui)

app/dns/cache_controller.go

@@ -3,6 +3,9 @@ package dns
 import (
 	"context"
 	go_errors "errors"
+	"sync"
+	"time"
+
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/errors"
 	"github.com/xtls/xray-core/common/net"
@@ -10,25 +13,27 @@ import (
 	"github.com/xtls/xray-core/common/task"
 	dns_feature "github.com/xtls/xray-core/features/dns"
 	"golang.org/x/net/dns/dnsmessage"
-	"sync"
-	"time"
 )
 
 type CacheController struct {
 	sync.RWMutex
-	ips          map[string]*record
+	ips             map[string]*record
-	pub          *pubsub.Service
+	pub             *pubsub.Service
-	cacheCleanup *task.Periodic
+	cacheCleanup    *task.Periodic
-	name         string
+	name            string
-	disableCache bool
+	disableCache    bool
+	serveStale      bool
+	serveExpiredTTL int32
 }
 
-func NewCacheController(name string, disableCache bool) *CacheController {
+func NewCacheController(name string, disableCache bool, serveStale bool, serveExpiredTTL uint32) *CacheController {
 	c := &CacheController{
-		name:         name,
+		name:            name,
-		disableCache: disableCache,
+		disableCache:    disableCache,
-		ips:          make(map[string]*record),
+		serveStale:      serveStale,
-		pub:          pubsub.NewService(),
+		serveExpiredTTL: -int32(serveExpiredTTL),
+		ips:             make(map[string]*record),
+		pub:             pubsub.NewService(),
 	}
 
 	c.cacheCleanup = &task.Periodic{
@@ -41,6 +46,10 @@ func NewCacheController(name string, disableCache bool) *CacheController {
 // CacheCleanup clears expired items from cache
 func (c *CacheController) CacheCleanup() error {
 	now := time.Now()
+	if c.serveStale && c.serveExpiredTTL != 0 {
+		now = now.Add(time.Duration(c.serveExpiredTTL) * time.Second)
+	}
+
 	c.Lock()
 	defer c.Unlock()
 
@@ -93,78 +102,80 @@ func (c *CacheController) updateIP(req *dnsRequest, ipRec *IPRecord) {
 	switch req.reqType {
 	case dnsmessage.TypeA:
 		c.pub.Publish(req.domain+"4", nil)
-		if !c.disableCache {
-			_, _, err := rec.AAAA.getIPs()
-			if !go_errors.Is(err, errRecordNotFound) {
-				c.pub.Publish(req.domain+"6", nil)
-			}
-		}
 	case dnsmessage.TypeAAAA:
 		c.pub.Publish(req.domain+"6", nil)
-		if !c.disableCache {
-			_, _, err := rec.A.getIPs()
-			if !go_errors.Is(err, errRecordNotFound) {
-				c.pub.Publish(req.domain+"4", nil)
-			}
-		}
 	}
 
 	c.Unlock()
-	common.Must(c.cacheCleanup.Start())
+	if !c.serveStale || c.serveExpiredTTL != 0 {
+		common.Must(c.cacheCleanup.Start())
+	}
 }
 
-func (c *CacheController) findIPsForDomain(domain string, option dns_feature.IPOption) ([]net.IP, uint32, error) {
+func (c *CacheController) findIPsForDomain(domain string, option dns_feature.IPOption) ([]net.IP, int32, bool, bool, error) {
 	c.RLock()
 	record, found := c.ips[domain]
 	c.RUnlock()
 
 	if !found {
-		return nil, 0, errRecordNotFound
+		return nil, 0, true, true, errRecordNotFound
 	}
 
 	var errs []error
 	var allIPs []net.IP
-	var rTTL uint32 = dns_feature.DefaultTTL
+	var rTTL int32 = dns_feature.DefaultTTL
 
 	mergeReq := option.IPv4Enable && option.IPv6Enable
 
+	isARecordExpired := true
 	if option.IPv4Enable {
 		ips, ttl, err := record.A.getIPs()
-		if !mergeReq || go_errors.Is(err, errRecordNotFound) {
+		if ttl > 0 {
-			return ips, ttl, err
+			isARecordExpired = false
+		}
+		if !mergeReq {
+			return ips, ttl, isARecordExpired, true, err
 		}
 		if ttl < rTTL {
 			rTTL = ttl
 		}
 		if len(ips) > 0 {
 			allIPs = append(allIPs, ips...)
-		} else {
-			errs = append(errs, err)
 		}
+		errs = append(errs, err)
+
 	}
 
+	isAAAARecordExpired := true
 	if option.IPv6Enable {
 		ips, ttl, err := record.AAAA.getIPs()
-		if !mergeReq || go_errors.Is(err, errRecordNotFound) {
+		if ttl > 0 {
-			return ips, ttl, err
+			isAAAARecordExpired = false
+		}
+		if !mergeReq {
+			return ips, ttl, true, isAAAARecordExpired, err
 		}
 		if ttl < rTTL {
 			rTTL = ttl
 		}
 		if len(ips) > 0 {
 			allIPs = append(allIPs, ips...)
-		} else {
-			errs = append(errs, err)
 		}
+		errs = append(errs, err)
+
+	}
+
+	if go_errors.Is(errs[0], errRecordNotFound) || go_errors.Is(errs[1], errRecordNotFound) {
+		return nil, 0, isARecordExpired, isAAAARecordExpired, errRecordNotFound
 	}
 
 	if len(allIPs) > 0 {
-		return allIPs, rTTL, nil
+		return allIPs, rTTL, isARecordExpired, isAAAARecordExpired, nil
 	}
 	if go_errors.Is(errs[0], errs[1]) {
-		return nil, rTTL, errs[0]
+		return nil, rTTL, isARecordExpired, isAAAARecordExpired, errs[0]
 	}
-	return nil, rTTL, errors.Combine(errs...)
+	return nil, rTTL, isARecordExpired, isAAAARecordExpired, errors.Combine(errs...)
 }
 
 func (c *CacheController) registerSubscribers(domain string, option dns_feature.IPOption) (sub4 *pubsub.Subscriber, sub6 *pubsub.Subscriber) {

app/dns/config.pb.go

@@ -1,7 +1,7 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
 // 	protoc-gen-go v1.35.1
-// 	protoc        v5.28.2
+// 	protoc        v5.29.4
 // source: app/dns/config.proto
 
 package dns
@@ -142,6 +142,8 @@ type NameServer struct {
 	Tag               string                       `protobuf:"bytes,9,opt,name=tag,proto3" json:"tag,omitempty"`
 	TimeoutMs         uint64                       `protobuf:"varint,10,opt,name=timeoutMs,proto3" json:"timeoutMs,omitempty"`
 	DisableCache      bool                         `protobuf:"varint,11,opt,name=disableCache,proto3" json:"disableCache,omitempty"`
+	ServeStale        bool                         `protobuf:"varint,15,opt,name=serveStale,proto3" json:"serveStale,omitempty"`
+	ServeExpiredTTL   *uint32                      `protobuf:"varint,16,opt,name=serveExpiredTTL,proto3,oneof" json:"serveExpiredTTL,omitempty"`
 	FinalQuery        bool                         `protobuf:"varint,12,opt,name=finalQuery,proto3" json:"finalQuery,omitempty"`
 	UnexpectedGeoip   []*router.GeoIP              `protobuf:"bytes,13,rep,name=unexpected_geoip,json=unexpectedGeoip,proto3" json:"unexpected_geoip,omitempty"`
 	ActUnprior        bool                         `protobuf:"varint,14,opt,name=actUnprior,proto3" json:"actUnprior,omitempty"`
@@ -254,6 +256,20 @@ func (x *NameServer) GetDisableCache() bool {
 	return false
 }
 
+func (x *NameServer) GetServeStale() bool {
+	if x != nil {
+		return x.ServeStale
+	}
+	return false
+}
+
+func (x *NameServer) GetServeExpiredTTL() uint32 {
+	if x != nil && x.ServeExpiredTTL != nil {
+		return *x.ServeExpiredTTL
+	}
+	return 0
+}
+
 func (x *NameServer) GetFinalQuery() bool {
 	if x != nil {
 		return x.FinalQuery
@@ -291,6 +307,8 @@ type Config struct {
 	Tag string `protobuf:"bytes,6,opt,name=tag,proto3" json:"tag,omitempty"`
 	// DisableCache disables DNS cache
 	DisableCache           bool          `protobuf:"varint,8,opt,name=disableCache,proto3" json:"disableCache,omitempty"`
+	ServeStale             bool          `protobuf:"varint,12,opt,name=serveStale,proto3" json:"serveStale,omitempty"`
+	ServeExpiredTTL        uint32        `protobuf:"varint,13,opt,name=serveExpiredTTL,proto3" json:"serveExpiredTTL,omitempty"`
 	QueryStrategy          QueryStrategy `protobuf:"varint,9,opt,name=query_strategy,json=queryStrategy,proto3,enum=xray.app.dns.QueryStrategy" json:"query_strategy,omitempty"`
 	DisableFallback        bool          `protobuf:"varint,10,opt,name=disableFallback,proto3" json:"disableFallback,omitempty"`
 	DisableFallbackIfMatch bool          `protobuf:"varint,11,opt,name=disableFallbackIfMatch,proto3" json:"disableFallbackIfMatch,omitempty"`
@@ -361,6 +379,20 @@ func (x *Config) GetDisableCache() bool {
 	return false
 }
 
+func (x *Config) GetServeStale() bool {
+	if x != nil {
+		return x.ServeStale
+	}
+	return false
+}
+
+func (x *Config) GetServeExpiredTTL() uint32 {
+	if x != nil {
+		return x.ServeExpiredTTL
+	}
+	return 0
+}
+
 func (x *Config) GetQueryStrategy() QueryStrategy {
 	if x != nil {
 		return x.QueryStrategy
@@ -567,7 +599,7 @@ var file_app_dns_config_proto_rawDesc = []byte{
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@@ -601,72 +633,83 @@ var file_app_dns_config_proto_rawDesc = []byte{
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 }
 
 var (
@@ -718,6 +761,7 @@ func file_app_dns_config_proto_init() {
 	if File_app_dns_config_proto != nil {
 		return
 	}
+	file_app_dns_config_proto_msgTypes[0].OneofWrappers = []any{}
 	type x struct{}
 	out := protoimpl.TypeBuilder{
 		File: protoimpl.DescBuilder{

app/dns/config.proto

@@ -32,6 +32,8 @@ message NameServer {
   string tag = 9;
   uint64 timeoutMs = 10;
   bool disableCache = 11;
+  bool serveStale = 15;
+  optional uint32 serveExpiredTTL = 16;
   bool finalQuery = 12;
   repeated xray.app.router.GeoIP unexpected_geoip = 13;
   bool actUnprior = 14;
@@ -80,6 +82,8 @@ message Config {
 
   // DisableCache disables DNS cache
   bool disableCache = 8;
+  bool serveStale = 12;
+  uint32 serveExpiredTTL = 13;
 
   QueryStrategy query_strategy = 9;
 

app/dns/dns.go

@@ -118,6 +118,11 @@ func New(ctx context.Context, config *Config) (*DNS, error) {
 		}
 
 		disableCache := config.DisableCache || ns.DisableCache
+		serveStale := config.ServeStale || ns.ServeStale
+		serveExpiredTTL := config.ServeExpiredTTL
+		if ns.ServeExpiredTTL != nil {
+			serveExpiredTTL = *ns.ServeExpiredTTL
+		}
 
 		var tag = defaultTag
 		if len(ns.Tag) > 0 {
@@ -128,7 +133,7 @@ func New(ctx context.Context, config *Config) (*DNS, error) {
 			return nil, errors.New("no QueryStrategy available for ", ns.Address)
 		}
 
-		client, err := NewClient(ctx, ns, myClientIP, disableCache, tag, clientIPOption, &matcherInfos, updateDomain)
+		client, err := NewClient(ctx, ns, myClientIP, disableCache, serveStale, serveExpiredTTL, tag, clientIPOption, &matcherInfos, updateDomain)
 		if err != nil {
 			return nil, errors.New("failed to create client").Base(err)
 		}

app/dns/dnscommon.go

@@ -3,6 +3,7 @@ package dns
 import (
 	"context"
 	"encoding/binary"
+	"math"
 	"strings"
 	"time"
 
@@ -38,19 +39,14 @@ type IPRecord struct {
 	RawHeader *dnsmessage.Header
 }
 
-func (r *IPRecord) getIPs() ([]net.IP, uint32, error) {
+func (r *IPRecord) getIPs() ([]net.IP, int32, error) {
 	if r == nil {
 		return nil, 0, errRecordNotFound
 	}
-	untilExpire := time.Until(r.Expire).Seconds()
-	if untilExpire <= 0 {
-		return nil, 0, errRecordNotFound
-	}
 
-	ttl := uint32(untilExpire) + 1
+	untilExpire := time.Until(r.Expire).Seconds()
-	if ttl == 1 {
+	ttl := int32(math.Ceil(untilExpire))
-		r.Expire = time.Now().Add(time.Second) // To ensure that two consecutive requests get the same result
+
-	}
 	if r.RCode != dnsmessage.RCodeSuccess {
 		return nil, ttl, dns_feature.RCodeError(r.RCode)
 	}

app/dns/nameserver.go

@@ -41,7 +41,7 @@ type Client struct {
 }
 
 // NewServer creates a name server object according to the network destination url.
-func NewServer(ctx context.Context, dest net.Destination, dispatcher routing.Dispatcher, disableCache bool, clientIP net.IP) (Server, error) {
+func NewServer(ctx context.Context, dest net.Destination, dispatcher routing.Dispatcher, disableCache bool, serveStale bool, serveExpiredTTL uint32, clientIP net.IP) (Server, error) {
 	if address := dest.Address; address.Family().IsDomain() {
 		u, err := url.Parse(address.Domain())
 		if err != nil {
@@ -51,19 +51,19 @@ func NewServer(ctx context.Context, dest net.Destination, dispatcher routing.Dis
 		case strings.EqualFold(u.String(), "localhost"):
 			return NewLocalNameServer(), nil
 		case strings.EqualFold(u.Scheme, "https"): // DNS-over-HTTPS Remote mode
-			return NewDoHNameServer(u, dispatcher, false, disableCache, clientIP), nil
+			return NewDoHNameServer(u, dispatcher, false, disableCache, serveStale, serveExpiredTTL, clientIP), nil
 		case strings.EqualFold(u.Scheme, "h2c"): // DNS-over-HTTPS h2c Remote mode
-			return NewDoHNameServer(u, dispatcher, true, disableCache, clientIP), nil
+			return NewDoHNameServer(u, dispatcher, true, disableCache, serveStale, serveExpiredTTL, clientIP), nil
 		case strings.EqualFold(u.Scheme, "https+local"): // DNS-over-HTTPS Local mode
-			return NewDoHNameServer(u, nil, false, disableCache, clientIP), nil
+			return NewDoHNameServer(u, nil, false, disableCache, serveStale, serveExpiredTTL, clientIP), nil
 		case strings.EqualFold(u.Scheme, "h2c+local"): // DNS-over-HTTPS h2c Local mode
-			return NewDoHNameServer(u, nil, true, disableCache, clientIP), nil
+			return NewDoHNameServer(u, nil, true, disableCache, serveStale, serveExpiredTTL, clientIP), nil
 		case strings.EqualFold(u.Scheme, "quic+local"): // DNS-over-QUIC Local mode
-			return NewQUICNameServer(u, disableCache, clientIP)
+			return NewQUICNameServer(u, disableCache, serveStale, serveExpiredTTL, clientIP)
 		case strings.EqualFold(u.Scheme, "tcp"): // DNS-over-TCP Remote mode
-			return NewTCPNameServer(u, dispatcher, disableCache, clientIP)
+			return NewTCPNameServer(u, dispatcher, disableCache, serveStale, serveExpiredTTL, clientIP)
 		case strings.EqualFold(u.Scheme, "tcp+local"): // DNS-over-TCP Local mode
-			return NewTCPLocalNameServer(u, disableCache, clientIP)
+			return NewTCPLocalNameServer(u, disableCache, serveStale, serveExpiredTTL, clientIP)
 		case strings.EqualFold(u.String(), "fakedns"):
 			var fd dns.FakeDNSEngine
 			err = core.RequireFeatures(ctx, func(fdns dns.FakeDNSEngine) {
@@ -79,7 +79,7 @@ func NewServer(ctx context.Context, dest net.Destination, dispatcher routing.Dis
 		dest.Network = net.Network_UDP
 	}
 	if dest.Network == net.Network_UDP { // UDP classic DNS mode
-		return NewClassicNameServer(dest, dispatcher, disableCache, clientIP), nil
+		return NewClassicNameServer(dest, dispatcher, disableCache, serveStale, serveExpiredTTL, clientIP), nil
 	}
 	return nil, errors.New("No available name server could be created from ", dest).AtWarning()
 }
@@ -89,7 +89,7 @@ func NewClient(
 	ctx context.Context,
 	ns *NameServer,
 	clientIP net.IP,
-	disableCache bool,
+	disableCache bool, serveStale bool, serveExpiredTTL uint32,
 	tag string,
 	ipOption dns.IPOption,
 	matcherInfos *[]*DomainMatcherInfo,
@@ -99,7 +99,7 @@ func NewClient(
 
 	err := core.RequireFeatures(ctx, func(dispatcher routing.Dispatcher) error {
 		// Create a new server for each client for now
-		server, err := NewServer(ctx, ns.Address.AsDestination(), dispatcher, disableCache, clientIP)
+		server, err := NewServer(ctx, ns.Address.AsDestination(), dispatcher, disableCache, serveStale, serveExpiredTTL, clientIP)
 		if err != nil {
 			return errors.New("failed to create nameserver").Base(err).AtWarning()
 		}

app/dns/nameserver_doh.go

@@ -38,7 +38,7 @@ type DoHNameServer struct {
 }
 
 // NewDoHNameServer creates DOH/DOHL client object for remote/local resolving.
-func NewDoHNameServer(url *url.URL, dispatcher routing.Dispatcher, h2c bool, disableCache bool, clientIP net.IP) *DoHNameServer {
+func NewDoHNameServer(url *url.URL, dispatcher routing.Dispatcher, h2c bool, disableCache bool, serveStale bool, serveExpiredTTL uint32, clientIP net.IP) *DoHNameServer {
 	url.Scheme = "https"
 	mode := "DOH"
 	if dispatcher == nil {
@@ -46,7 +46,7 @@ func NewDoHNameServer(url *url.URL, dispatcher routing.Dispatcher, h2c bool, dis
 	}
 	errors.LogInfo(context.Background(), "DNS: created ", mode, " client for ", url.String(), ", with h2c ", h2c)
 	s := &DoHNameServer{
-		cacheController: NewCacheController(mode+"//"+url.Host, disableCache),
+		cacheController: NewCacheController(mode+"//"+url.Host, disableCache, serveStale, serveExpiredTTL),
 		dohURL:          url.String(),
 		clientIP:        clientIP,
 	}
@@ -126,7 +126,9 @@ func (s *DoHNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- er
 
 	if s.Name()+"." == "DOH//"+domain {
 		errors.LogError(ctx, s.Name(), " tries to resolve itself! Use IP or set \"hosts\" instead.")
-		noResponseErrCh <- errors.New("tries to resolve itself!", s.Name())
+		if noResponseErrCh != nil {
+			noResponseErrCh <- errors.New("tries to resolve itself!", s.Name())
+		}
 		return
 	}
 
@@ -167,19 +169,25 @@ func (s *DoHNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- er
 			b, err := dns.PackMessage(r.msg)
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to pack dns query for ", domain)
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			resp, err := s.dohHTTPSContext(dnsCtx, b.Bytes())
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to retrieve response for ", domain)
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			rec, err := parseResponse(resp)
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to handle DOH response for ", domain)
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			s.cacheController.updateIP(r, rec)
@@ -221,19 +229,38 @@ func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, option dns_f
 	sub4, sub6 := s.cacheController.registerSubscribers(fqdn, option)
 	defer closeSubscribers(sub4, sub6)
 
+	queryOption := option
+
 	if s.cacheController.disableCache {
 		errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.Name())
 	} else {
-		ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
+		ips, ttl, isARecordExpired, isAAAARecordExpired, err := s.cacheController.findIPsForDomain(fqdn, option)
+		if sub4 != nil && !isARecordExpired {
+			sub4.Close()
+			sub4 = nil
+			queryOption.IPv4Enable = false
+		}
+		if sub6 != nil && !isAAAARecordExpired {
+			sub6.Close()
+			sub6 = nil
+			queryOption.IPv6Enable = false
+		}
 		if !go_errors.Is(err, errRecordNotFound) {
-			errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
+			if ttl > 0 {
-			log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
+				errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
-			return ips, ttl, err
+				log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
+				return ips, uint32(ttl), err
+			}
+			if s.cacheController.serveStale && (s.cacheController.serveExpiredTTL == 0 || s.cacheController.serveExpiredTTL < ttl) {
+				errors.LogDebugInner(ctx, err, s.Name(), " cache OPTIMISTE ", domain, " -> ", ips)
+				s.sendQuery(ctx, nil, fqdn, queryOption)
+				return ips, 1, err
+			}
 		}
 	}
 
 	noResponseErrCh := make(chan error, 2)
-	s.sendQuery(ctx, noResponseErrCh, fqdn, option)
+	s.sendQuery(ctx, noResponseErrCh, fqdn, queryOption)
 	start := time.Now()
 
 	if sub4 != nil {
@@ -257,8 +284,13 @@ func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, option dns_f
 		}
 	}
 
-	ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
+	ips, ttl, _, _, err := s.cacheController.findIPsForDomain(fqdn, option)
 	log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSQueried, Elapsed: time.Since(start), Error: err})
-	return ips, ttl, err
+	var rTTL uint32
-
+	if ttl <= 0 {
+		rTTL = 1
+	} else {
+		rTTL = uint32(ttl)
+	}
+	return ips, rTTL, err
 }

app/dns/nameserver_doh_test.go

@@ -17,7 +17,7 @@ func TestDOHNameServer(t *testing.T) {
 	url, err := url.Parse("https+local://1.1.1.1/dns-query")
 	common.Must(err)
 
-	s := NewDoHNameServer(url, nil, false, false, net.IP(nil))
+	s := NewDoHNameServer(url, nil, false, false, false, 0, net.IP(nil))
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{
 		IPv4Enable: true,
@@ -34,7 +34,7 @@ func TestDOHNameServerWithCache(t *testing.T) {
 	url, err := url.Parse("https+local://1.1.1.1/dns-query")
 	common.Must(err)
 
-	s := NewDoHNameServer(url, nil, false, false, net.IP(nil))
+	s := NewDoHNameServer(url, nil, false, false, false, 0, net.IP(nil))
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{
 		IPv4Enable: true,
@@ -62,7 +62,7 @@ func TestDOHNameServerWithIPv4Override(t *testing.T) {
 	url, err := url.Parse("https+local://1.1.1.1/dns-query")
 	common.Must(err)
 
-	s := NewDoHNameServer(url, nil, false, false, net.IP(nil))
+	s := NewDoHNameServer(url, nil, false, false, false, 0, net.IP(nil))
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{
 		IPv4Enable: true,
@@ -85,7 +85,7 @@ func TestDOHNameServerWithIPv6Override(t *testing.T) {
 	url, err := url.Parse("https+local://1.1.1.1/dns-query")
 	common.Must(err)
 
-	s := NewDoHNameServer(url, nil, false, false, net.IP(nil))
+	s := NewDoHNameServer(url, nil, false, false, false, 0, net.IP(nil))
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{
 		IPv4Enable: false,

app/dns/nameserver_quic.go

@@ -37,7 +37,7 @@ type QUICNameServer struct {
 }
 
 // NewQUICNameServer creates DNS-over-QUIC client object for local resolving
-func NewQUICNameServer(url *url.URL, disableCache bool, clientIP net.IP) (*QUICNameServer, error) {
+func NewQUICNameServer(url *url.URL, disableCache bool, serveStale bool, serveExpiredTTL uint32, clientIP net.IP) (*QUICNameServer, error) {
 	errors.LogInfo(context.Background(), "DNS: created Local DNS-over-QUIC client for ", url.String())
 
 	var err error
@@ -51,7 +51,7 @@ func NewQUICNameServer(url *url.URL, disableCache bool, clientIP net.IP) (*QUICN
 	dest := net.UDPDestination(net.ParseAddress(url.Hostname()), port)
 
 	s := &QUICNameServer{
-		cacheController: NewCacheController(url.String(), disableCache),
+		cacheController: NewCacheController(url.String(), disableCache, serveStale, serveExpiredTTL),
 		destination:     &dest,
 		clientIP:        clientIP,
 	}
@@ -103,7 +103,9 @@ func (s *QUICNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- e
 			b, err := dns.PackMessage(r.msg)
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to pack dns query")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 
@@ -111,13 +113,17 @@ func (s *QUICNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- e
 			err = binary.Write(dnsReqBuf, binary.BigEndian, uint16(b.Len()))
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "binary write failed")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			_, err = dnsReqBuf.Write(b.Bytes())
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "buffer write failed")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			b.Release()
@@ -125,14 +131,18 @@ func (s *QUICNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- e
 			conn, err := s.openStream(dnsCtx)
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to open quic connection")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 
 			_, err = conn.Write(dnsReqBuf.Bytes())
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to send query")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 
@@ -143,28 +153,36 @@ func (s *QUICNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- e
 			n, err := respBuf.ReadFullFrom(conn, 2)
 			if err != nil && n == 0 {
 				errors.LogErrorInner(ctx, err, "failed to read response length")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			var length int16
 			err = binary.Read(bytes.NewReader(respBuf.Bytes()), binary.BigEndian, &length)
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to parse response length")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			respBuf.Clear()
 			n, err = respBuf.ReadFullFrom(conn, int32(length))
 			if err != nil && n == 0 {
 				errors.LogErrorInner(ctx, err, "failed to read response length")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 
 			rec, err := parseResponse(respBuf.Bytes())
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to handle response")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			s.cacheController.updateIP(r, rec)
@@ -178,19 +196,38 @@ func (s *QUICNameServer) QueryIP(ctx context.Context, domain string, option dns_
 	sub4, sub6 := s.cacheController.registerSubscribers(fqdn, option)
 	defer closeSubscribers(sub4, sub6)
 
+	queryOption := option
+
 	if s.cacheController.disableCache {
 		errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.Name())
 	} else {
-		ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
+		ips, ttl, isARecordExpired, isAAAARecordExpired, err := s.cacheController.findIPsForDomain(fqdn, option)
+		if sub4 != nil && !isARecordExpired {
+			sub4.Close()
+			sub4 = nil
+			queryOption.IPv4Enable = false
+		}
+		if sub6 != nil && !isAAAARecordExpired {
+			sub6.Close()
+			sub6 = nil
+			queryOption.IPv6Enable = false
+		}
 		if !go_errors.Is(err, errRecordNotFound) {
-			errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
+			if ttl > 0 {
-			log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
+				errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
-			return ips, ttl, err
+				log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
+				return ips, uint32(ttl), err
+			}
+			if s.cacheController.serveStale && (s.cacheController.serveExpiredTTL == 0 || s.cacheController.serveExpiredTTL < ttl) {
+				errors.LogDebugInner(ctx, err, s.Name(), " cache OPTIMISTE ", domain, " -> ", ips)
+				s.sendQuery(ctx, nil, fqdn, queryOption)
+				return ips, 1, err
+			}
 		}
 	}
 
 	noResponseErrCh := make(chan error, 2)
-	s.sendQuery(ctx, noResponseErrCh, fqdn, option)
+	s.sendQuery(ctx, noResponseErrCh, fqdn, queryOption)
 	start := time.Now()
 
 	if sub4 != nil {
@@ -214,10 +251,15 @@ func (s *QUICNameServer) QueryIP(ctx context.Context, domain string, option dns_
 		}
 	}
 
-	ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
+	ips, ttl, _, _, err := s.cacheController.findIPsForDomain(fqdn, option)
 	log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSQueried, Elapsed: time.Since(start), Error: err})
-	return ips, ttl, err
+	var rTTL uint32
-
+	if ttl <= 0 {
+		rTTL = 1
+	} else {
+		rTTL = uint32(ttl)
+	}
+	return ips, rTTL, err
 }
 
 func isActive(s *quic.Conn) bool {

app/dns/nameserver_quic_test.go

@@ -16,7 +16,7 @@ import (
 func TestQUICNameServer(t *testing.T) {
 	url, err := url.Parse("quic://dns.adguard-dns.com")
 	common.Must(err)
-	s, err := NewQUICNameServer(url, false, net.IP(nil))
+	s, err := NewQUICNameServer(url, false, false, 0, net.IP(nil))
 	common.Must(err)
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns.IPOption{
@@ -43,7 +43,7 @@ func TestQUICNameServer(t *testing.T) {
 func TestQUICNameServerWithIPv4Override(t *testing.T) {
 	url, err := url.Parse("quic://dns.adguard-dns.com")
 	common.Must(err)
-	s, err := NewQUICNameServer(url, false, net.IP(nil))
+	s, err := NewQUICNameServer(url, false, false, 0, net.IP(nil))
 	common.Must(err)
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns.IPOption{
@@ -66,7 +66,7 @@ func TestQUICNameServerWithIPv4Override(t *testing.T) {
 func TestQUICNameServerWithIPv6Override(t *testing.T) {
 	url, err := url.Parse("quic://dns.adguard-dns.com")
 	common.Must(err)
-	s, err := NewQUICNameServer(url, false, net.IP(nil))
+	s, err := NewQUICNameServer(url, false, false, 0, net.IP(nil))
 	common.Must(err)
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns.IPOption{

app/dns/nameserver_tcp.go

@@ -34,10 +34,10 @@ type TCPNameServer struct {
 func NewTCPNameServer(
 	url *url.URL,
 	dispatcher routing.Dispatcher,
-	disableCache bool,
+	disableCache bool, serveStale bool, serveExpiredTTL uint32,
 	clientIP net.IP,
 ) (*TCPNameServer, error) {
-	s, err := baseTCPNameServer(url, "TCP", disableCache, clientIP)
+	s, err := baseTCPNameServer(url, "TCP", disableCache, serveStale, serveExpiredTTL, clientIP)
 	if err != nil {
 		return nil, err
 	}
@@ -58,8 +58,8 @@ func NewTCPNameServer(
 }
 
 // NewTCPLocalNameServer creates DNS over TCP client object for local resolving
-func NewTCPLocalNameServer(url *url.URL, disableCache bool, clientIP net.IP) (*TCPNameServer, error) {
+func NewTCPLocalNameServer(url *url.URL, disableCache bool, serveStale bool, serveExpiredTTL uint32, clientIP net.IP) (*TCPNameServer, error) {
-	s, err := baseTCPNameServer(url, "TCPL", disableCache, clientIP)
+	s, err := baseTCPNameServer(url, "TCPL", disableCache, serveStale, serveExpiredTTL, clientIP)
 	if err != nil {
 		return nil, err
 	}
@@ -71,7 +71,7 @@ func NewTCPLocalNameServer(url *url.URL, disableCache bool, clientIP net.IP) (*T
 	return s, nil
 }
 
-func baseTCPNameServer(url *url.URL, prefix string, disableCache bool, clientIP net.IP) (*TCPNameServer, error) {
+func baseTCPNameServer(url *url.URL, prefix string, disableCache bool, serveStale bool, serveExpiredTTL uint32, clientIP net.IP) (*TCPNameServer, error) {
 	port := net.Port(53)
 	if url.Port() != "" {
 		var err error
@@ -82,7 +82,7 @@ func baseTCPNameServer(url *url.URL, prefix string, disableCache bool, clientIP
 	dest := net.TCPDestination(net.ParseAddress(url.Hostname()), port)
 
 	s := &TCPNameServer{
-		cacheController: NewCacheController(prefix+"//"+dest.NetAddr(), disableCache),
+		cacheController: NewCacheController(prefix+"//"+dest.NetAddr(), disableCache, serveStale, serveExpiredTTL),
 		destination:     &dest,
 		clientIP:        clientIP,
 	}
@@ -131,14 +131,18 @@ func (s *TCPNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- er
 			b, err := dns.PackMessage(r.msg)
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to pack dns query")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 
 			conn, err := s.dial(dnsCtx)
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to dial namesever")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			defer conn.Close()
@@ -146,13 +150,17 @@ func (s *TCPNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- er
 			err = binary.Write(dnsReqBuf, binary.BigEndian, uint16(b.Len()))
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "binary write failed")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			_, err = dnsReqBuf.Write(b.Bytes())
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "buffer write failed")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			b.Release()
@@ -160,7 +168,9 @@ func (s *TCPNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- er
 			_, err = conn.Write(dnsReqBuf.Bytes())
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to send query")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			dnsReqBuf.Release()
@@ -170,28 +180,36 @@ func (s *TCPNameServer) sendQuery(ctx context.Context, noResponseErrCh chan<- er
 			n, err := respBuf.ReadFullFrom(conn, 2)
 			if err != nil && n == 0 {
 				errors.LogErrorInner(ctx, err, "failed to read response length")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			var length int16
 			err = binary.Read(bytes.NewReader(respBuf.Bytes()), binary.BigEndian, &length)
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to parse response length")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 			respBuf.Clear()
 			n, err = respBuf.ReadFullFrom(conn, int32(length))
 			if err != nil && n == 0 {
 				errors.LogErrorInner(ctx, err, "failed to read response length")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 
 			rec, err := parseResponse(respBuf.Bytes())
 			if err != nil {
 				errors.LogErrorInner(ctx, err, "failed to parse DNS over TCP response")
-				noResponseErrCh <- err
+				if noResponseErrCh != nil {
+					noResponseErrCh <- err
+				}
 				return
 			}
 
@@ -206,19 +224,38 @@ func (s *TCPNameServer) QueryIP(ctx context.Context, domain string, option dns_f
 	sub4, sub6 := s.cacheController.registerSubscribers(fqdn, option)
 	defer closeSubscribers(sub4, sub6)
 
+	queryOption := option
+
 	if s.cacheController.disableCache {
 		errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.Name())
 	} else {
-		ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
+		ips, ttl, isARecordExpired, isAAAARecordExpired, err := s.cacheController.findIPsForDomain(fqdn, option)
+		if sub4 != nil && !isARecordExpired {
+			sub4.Close()
+			sub4 = nil
+			queryOption.IPv4Enable = false
+		}
+		if sub6 != nil && !isAAAARecordExpired {
+			sub6.Close()
+			sub6 = nil
+			queryOption.IPv6Enable = false
+		}
 		if !go_errors.Is(err, errRecordNotFound) {
-			errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
+			if ttl > 0 {
-			log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
+				errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
-			return ips, ttl, err
+				log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
+				return ips, uint32(ttl), err
+			}
+			if s.cacheController.serveStale && (s.cacheController.serveExpiredTTL == 0 || s.cacheController.serveExpiredTTL < ttl) {
+				errors.LogDebugInner(ctx, err, s.Name(), " cache OPTIMISTE ", domain, " -> ", ips)
+				s.sendQuery(ctx, nil, fqdn, queryOption)
+				return ips, 1, err
+			}
 		}
 	}
 
 	noResponseErrCh := make(chan error, 2)
-	s.sendQuery(ctx, noResponseErrCh, fqdn, option)
+	s.sendQuery(ctx, noResponseErrCh, fqdn, queryOption)
 	start := time.Now()
 
 	if sub4 != nil {
@@ -242,8 +279,13 @@ func (s *TCPNameServer) QueryIP(ctx context.Context, domain string, option dns_f
 		}
 	}
 
-	ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
+	ips, ttl, _, _, err := s.cacheController.findIPsForDomain(fqdn, option)
 	log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSQueried, Elapsed: time.Since(start), Error: err})
-	return ips, ttl, err
+	var rTTL uint32
-
+	if ttl <= 0 {
+		rTTL = 1
+	} else {
+		rTTL = uint32(ttl)
+	}
+	return ips, rTTL, err
 }

app/dns/nameserver_tcp_test.go

@@ -16,7 +16,7 @@ import (
 func TestTCPLocalNameServer(t *testing.T) {
 	url, err := url.Parse("tcp+local://8.8.8.8")
 	common.Must(err)
-	s, err := NewTCPLocalNameServer(url, false, net.IP(nil))
+	s, err := NewTCPLocalNameServer(url, false, false, 0, net.IP(nil))
 	common.Must(err)
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{
@@ -33,7 +33,7 @@ func TestTCPLocalNameServer(t *testing.T) {
 func TestTCPLocalNameServerWithCache(t *testing.T) {
 	url, err := url.Parse("tcp+local://8.8.8.8")
 	common.Must(err)
-	s, err := NewTCPLocalNameServer(url, false, net.IP(nil))
+	s, err := NewTCPLocalNameServer(url, false, false, 0, net.IP(nil))
 	common.Must(err)
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{
@@ -61,7 +61,7 @@ func TestTCPLocalNameServerWithCache(t *testing.T) {
 func TestTCPLocalNameServerWithIPv4Override(t *testing.T) {
 	url, err := url.Parse("tcp+local://8.8.8.8")
 	common.Must(err)
-	s, err := NewTCPLocalNameServer(url, false, net.IP(nil))
+	s, err := NewTCPLocalNameServer(url, false, false, 0, net.IP(nil))
 	common.Must(err)
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{
@@ -85,7 +85,7 @@ func TestTCPLocalNameServerWithIPv4Override(t *testing.T) {
 func TestTCPLocalNameServerWithIPv6Override(t *testing.T) {
 	url, err := url.Parse("tcp+local://8.8.8.8")
 	common.Must(err)
-	s, err := NewTCPLocalNameServer(url, false, net.IP(nil))
+	s, err := NewTCPLocalNameServer(url, false, false, 0, net.IP(nil))
 	common.Must(err)
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 	ips, _, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{

app/dns/nameserver_udp.go

@@ -39,14 +39,14 @@ type udpDnsRequest struct {
 }
 
 // NewClassicNameServer creates udp server object for remote resolving.
-func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher, disableCache bool, clientIP net.IP) *ClassicNameServer {
+func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher, disableCache bool, serveStale bool, serveExpiredTTL uint32, clientIP net.IP) *ClassicNameServer {
 	// default to 53 if unspecific
 	if address.Port == 0 {
 		address.Port = net.Port(53)
 	}
 
 	s := &ClassicNameServer{
-		cacheController: NewCacheController(strings.ToUpper(address.String()), disableCache),
+		cacheController: NewCacheController(strings.ToUpper(address.String()), disableCache, serveStale, serveExpiredTTL),
 		address:         &address,
 		requests:        make(map[uint16]*udpDnsRequest),
 		clientIP:        clientIP,
@@ -174,19 +174,38 @@ func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, option d
 	sub4, sub6 := s.cacheController.registerSubscribers(fqdn, option)
 	defer closeSubscribers(sub4, sub6)
 
+	queryOption := option
+
 	if s.cacheController.disableCache {
 		errors.LogDebug(ctx, "DNS cache is disabled. Querying IP for ", domain, " at ", s.Name())
 	} else {
-		ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
+		ips, ttl, isARecordExpired, isAAAARecordExpired, err := s.cacheController.findIPsForDomain(fqdn, option)
+		if sub4 != nil && !isARecordExpired {
+			sub4.Close()
+			sub4 = nil
+			queryOption.IPv4Enable = false
+		}
+		if sub6 != nil && !isAAAARecordExpired {
+			sub6.Close()
+			sub6 = nil
+			queryOption.IPv6Enable = false
+		}
 		if !go_errors.Is(err, errRecordNotFound) {
-			errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
+			if ttl > 0 {
-			log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
+				errors.LogDebugInner(ctx, err, s.Name(), " cache HIT ", domain, " -> ", ips)
-			return ips, ttl, err
+				log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSCacheHit, Elapsed: 0, Error: err})
+				return ips, uint32(ttl), err
+			}
+			if s.cacheController.serveStale && (s.cacheController.serveExpiredTTL == 0 || s.cacheController.serveExpiredTTL < ttl) {
+				errors.LogDebugInner(ctx, err, s.Name(), " cache OPTIMISTE ", domain, " -> ", ips)
+				s.sendQuery(ctx, nil, fqdn, queryOption)
+				return ips, 1, err
+			}
 		}
 	}
 
 	noResponseErrCh := make(chan error, 2)
-	s.sendQuery(ctx, noResponseErrCh, fqdn, option)
+	s.sendQuery(ctx, noResponseErrCh, fqdn, queryOption)
 	start := time.Now()
 
 	if sub4 != nil {
@@ -210,8 +229,13 @@ func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, option d
 		}
 	}
 
-	ips, ttl, err := s.cacheController.findIPsForDomain(fqdn, option)
+	ips, ttl, _, _, err := s.cacheController.findIPsForDomain(fqdn, option)
 	log.Record(&log.DNSLog{Server: s.Name(), Domain: domain, Result: ips, Status: log.DNSQueried, Elapsed: time.Since(start), Error: err})
-	return ips, ttl, err
+	var rTTL uint32
-
+	if ttl <= 0 {
+		rTTL = 1
+	} else {
+		rTTL = uint32(ttl)
+	}
+	return ips, rTTL, err
 }

app/proxyman/outbound/handler.go

@@ -108,7 +108,7 @@ func NewHandler(ctx context.Context, config *core.OutboundHandlerConfig) (outbou
 	}
 	h.proxyConfig = proxyConfig
 
-	ctx = session.ContextWithHandler(ctx, h)
+	ctx = session.ContextWithFullHandler(ctx, h)
 
 	rawProxyHandler, err := common.CreateObject(ctx, proxyConfig)
 	if err != nil {

app/reverse/bridge.go

@@ -198,9 +198,11 @@ func (w *BridgeWorker) handleInternalConn(link *transport.Link) {
 
 func (w *BridgeWorker) Dispatch(ctx context.Context, dest net.Destination) (*transport.Link, error) {
 	if !isInternalDomain(dest) {
-		ctx = session.ContextWithInbound(ctx, &session.Inbound{
+		if session.InboundFromContext(ctx) == nil {
-			Tag: w.Tag,
+			ctx = session.ContextWithInbound(ctx, &session.Inbound{
-		})
+				Tag: w.Tag,
+			})
+		}
 		return w.Dispatcher.Dispatch(ctx, dest)
 	}
 
@@ -221,9 +223,11 @@ func (w *BridgeWorker) Dispatch(ctx context.Context, dest net.Destination) (*tra
 
 func (w *BridgeWorker) DispatchLink(ctx context.Context, dest net.Destination, link *transport.Link) error {
 	if !isInternalDomain(dest) {
-		ctx = session.ContextWithInbound(ctx, &session.Inbound{
+		if session.InboundFromContext(ctx) == nil {
-			Tag: w.Tag,
+			ctx = session.ContextWithInbound(ctx, &session.Inbound{
-		})
+				Tag: w.Tag,
+			})
+		}
 		return w.Dispatcher.DispatchLink(ctx, dest, link)
 	}
 

common/mux/client.go

@@ -264,7 +264,11 @@ func fetchInput(ctx context.Context, s *Session, output buf.Writer) {
 		transferType = protocol.TransferTypePacket
 	}
 	s.transferType = transferType
-	writer := NewWriter(s.ID, ob.Target, output, transferType, xudp.GetGlobalID(ctx))
+	var inbound *session.Inbound
+	if session.IsReverseMuxFromContext(ctx) {
+		inbound = session.InboundFromContext(ctx)
+	}
+	writer := NewWriter(s.ID, ob.Target, output, transferType, xudp.GetGlobalID(ctx), inbound)
 	defer s.Close(false)
 	defer writer.Close()
 
@@ -384,7 +388,7 @@ func (m *ClientWorker) fetchOutput() {
 
 	var meta FrameMetadata
 	for {
-		err := meta.Unmarshal(reader)
+		err := meta.Unmarshal(reader, false)
 		if err != nil {
 			if errors.Cause(err) != io.EOF {
 				errors.LogInfoInner(context.Background(), err, "failed to read metadata")

common/mux/frame.go

@@ -11,6 +11,7 @@ import (
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/common/protocol"
 	"github.com/xtls/xray-core/common/serial"
+	"github.com/xtls/xray-core/common/session"
 )
 
 type SessionStatus byte
@@ -60,6 +61,7 @@ type FrameMetadata struct {
 	Option        bitmask.Byte
 	SessionStatus SessionStatus
 	GlobalID      [8]byte
+	Inbound       *session.Inbound
 }
 
 func (f FrameMetadata) WriteTo(b *buf.Buffer) error {
@@ -79,11 +81,23 @@ func (f FrameMetadata) WriteTo(b *buf.Buffer) error {
 		case net.Network_UDP:
 			common.Must(b.WriteByte(byte(TargetNetworkUDP)))
 		}
-
 		if err := addrParser.WriteAddressPort(b, f.Target.Address, f.Target.Port); err != nil {
 			return err
 		}
-		if b.UDP != nil { // make sure it's user's proxy request
+		if f.Inbound != nil {
+			if f.Inbound.Source.Network == net.Network_TCP || f.Inbound.Source.Network == net.Network_UDP {
+				common.Must(b.WriteByte(byte(f.Inbound.Source.Network - 1)))
+				if err := addrParser.WriteAddressPort(b, f.Inbound.Source.Address, f.Inbound.Source.Port); err != nil {
+					return err
+				}
+				if f.Inbound.Local.Network == net.Network_TCP || f.Inbound.Local.Network == net.Network_UDP {
+					common.Must(b.WriteByte(byte(f.Inbound.Local.Network - 1)))
+					if err := addrParser.WriteAddressPort(b, f.Inbound.Local.Address, f.Inbound.Local.Port); err != nil {
+						return err
+					}
+				}
+			}
+		} else if b.UDP != nil { // make sure it's user's proxy request
 			b.Write(f.GlobalID[:]) // no need to check whether it's empty
 		}
 	} else if b.UDP != nil {
@@ -97,7 +111,7 @@ func (f FrameMetadata) WriteTo(b *buf.Buffer) error {
 }
 
 // Unmarshal reads FrameMetadata from the given reader.
-func (f *FrameMetadata) Unmarshal(reader io.Reader) error {
+func (f *FrameMetadata) Unmarshal(reader io.Reader, readSourceAndLocal bool) error {
 	metaLen, err := serial.ReadUint16(reader)
 	if err != nil {
 		return err
@@ -112,12 +126,12 @@ func (f *FrameMetadata) Unmarshal(reader io.Reader) error {
 	if _, err := b.ReadFullFrom(reader, int32(metaLen)); err != nil {
 		return err
 	}
-	return f.UnmarshalFromBuffer(b)
+	return f.UnmarshalFromBuffer(b, readSourceAndLocal)
 }
 
 // UnmarshalFromBuffer reads a FrameMetadata from the given buffer.
 // Visible for testing only.
-func (f *FrameMetadata) UnmarshalFromBuffer(b *buf.Buffer) error {
+func (f *FrameMetadata) UnmarshalFromBuffer(b *buf.Buffer, readSourceAndLocal bool) error {
 	if b.Len() < 4 {
 		return errors.New("insufficient buffer: ", b.Len())
 	}
@@ -150,6 +164,54 @@ func (f *FrameMetadata) UnmarshalFromBuffer(b *buf.Buffer) error {
 		}
 	}
 
+	if f.SessionStatus == SessionStatusNew && readSourceAndLocal {
+		f.Inbound = &session.Inbound{}
+
+		if b.Len() == 0 {
+			return nil // for heartbeat, etc.
+		}
+		network := TargetNetwork(b.Byte(0))
+		if network == 0 {
+			return nil // may be padding
+		}
+		b.Advance(1)
+		addr, port, err := addrParser.ReadAddressPort(nil, b)
+		if err != nil {
+			return errors.New("reading source: failed to parse address and port").Base(err)
+		}
+		switch network {
+		case TargetNetworkTCP:
+			f.Inbound.Source = net.TCPDestination(addr, port)
+		case TargetNetworkUDP:
+			f.Inbound.Source = net.UDPDestination(addr, port)
+		default:
+			return errors.New("reading source: unknown network type: ", network)
+		}
+
+		if b.Len() == 0 {
+			return nil
+		}
+		network = TargetNetwork(b.Byte(0))
+		if network == 0 {
+			return nil
+		}
+		b.Advance(1)
+		addr, port, err = addrParser.ReadAddressPort(nil, b)
+		if err != nil {
+			return errors.New("reading local: failed to parse address and port").Base(err)
+		}
+		switch network {
+		case TargetNetworkTCP:
+			f.Inbound.Local = net.TCPDestination(addr, port)
+		case TargetNetworkUDP:
+			f.Inbound.Local = net.UDPDestination(addr, port)
+		default:
+			return errors.New("reading local: unknown network type: ", network)
+		}
+
+		return nil
+	}
+
 	// Application data is essential, to test whether the pipe is closed.
 	if f.SessionStatus == SessionStatusNew && f.Option.Has(OptionData) &&
 		f.Target.Network == net.Network_UDP && b.Len() >= 8 {

common/mux/mux_test.go

@@ -10,6 +10,7 @@ import (
 	. "github.com/xtls/xray-core/common/mux"
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/common/protocol"
+	"github.com/xtls/xray-core/common/session"
 	"github.com/xtls/xray-core/transport/pipe"
 )
 
@@ -32,13 +33,13 @@ func TestReaderWriter(t *testing.T) {
 	pReader, pWriter := pipe.New(pipe.WithSizeLimit(1024))
 
 	dest := net.TCPDestination(net.DomainAddress("example.com"), 80)
-	writer := NewWriter(1, dest, pWriter, protocol.TransferTypeStream, [8]byte{})
+	writer := NewWriter(1, dest, pWriter, protocol.TransferTypeStream, [8]byte{}, &session.Inbound{})
 
 	dest2 := net.TCPDestination(net.LocalHostIP, 443)
-	writer2 := NewWriter(2, dest2, pWriter, protocol.TransferTypeStream, [8]byte{})
+	writer2 := NewWriter(2, dest2, pWriter, protocol.TransferTypeStream, [8]byte{}, &session.Inbound{})
 
 	dest3 := net.TCPDestination(net.LocalHostIPv6, 18374)
-	writer3 := NewWriter(3, dest3, pWriter, protocol.TransferTypeStream, [8]byte{})
+	writer3 := NewWriter(3, dest3, pWriter, protocol.TransferTypeStream, [8]byte{}, &session.Inbound{})
 
 	writePayload := func(writer *Writer, payload ...byte) error {
 		b := buf.New()
@@ -62,7 +63,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		common.Must(meta.Unmarshal(bytesReader))
+		common.Must(meta.Unmarshal(bytesReader, false))
 		if r := cmp.Diff(meta, FrameMetadata{
 			SessionID:     1,
 			SessionStatus: SessionStatusNew,
@@ -81,7 +82,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		common.Must(meta.Unmarshal(bytesReader))
+		common.Must(meta.Unmarshal(bytesReader, false))
 		if r := cmp.Diff(meta, FrameMetadata{
 			SessionStatus: SessionStatusNew,
 			SessionID:     2,
@@ -94,7 +95,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		common.Must(meta.Unmarshal(bytesReader))
+		common.Must(meta.Unmarshal(bytesReader, false))
 		if r := cmp.Diff(meta, FrameMetadata{
 			SessionID:     1,
 			SessionStatus: SessionStatusKeep,
@@ -112,7 +113,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		common.Must(meta.Unmarshal(bytesReader))
+		common.Must(meta.Unmarshal(bytesReader, false))
 		if r := cmp.Diff(meta, FrameMetadata{
 			SessionID:     3,
 			SessionStatus: SessionStatusNew,
@@ -131,7 +132,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		common.Must(meta.Unmarshal(bytesReader))
+		common.Must(meta.Unmarshal(bytesReader, false))
 		if r := cmp.Diff(meta, FrameMetadata{
 			SessionID:     1,
 			SessionStatus: SessionStatusEnd,
@@ -143,7 +144,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		common.Must(meta.Unmarshal(bytesReader))
+		common.Must(meta.Unmarshal(bytesReader, false))
 		if r := cmp.Diff(meta, FrameMetadata{
 			SessionID:     3,
 			SessionStatus: SessionStatusEnd,
@@ -155,7 +156,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		common.Must(meta.Unmarshal(bytesReader))
+		common.Must(meta.Unmarshal(bytesReader, false))
 		if r := cmp.Diff(meta, FrameMetadata{
 			SessionID:     2,
 			SessionStatus: SessionStatusKeep,
@@ -173,7 +174,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		common.Must(meta.Unmarshal(bytesReader))
+		common.Must(meta.Unmarshal(bytesReader, false))
 		if r := cmp.Diff(meta, FrameMetadata{
 			SessionID:     2,
 			SessionStatus: SessionStatusEnd,
@@ -187,7 +188,7 @@ func TestReaderWriter(t *testing.T) {
 
 	{
 		var meta FrameMetadata
-		err := meta.Unmarshal(bytesReader)
+		err := meta.Unmarshal(bytesReader, false)
 		if err == nil {
 			t.Error("nil error")
 		}

common/mux/server.go

@@ -166,6 +166,14 @@ func (w *ServerWorker) handleStatusKeepAlive(meta *FrameMetadata, reader *buf.Bu
 
 func (w *ServerWorker) handleStatusNew(ctx context.Context, meta *FrameMetadata, reader *buf.BufferedReader) error {
 	ctx = session.SubContextFromMuxInbound(ctx)
+	if meta.Inbound != nil && meta.Inbound.Source.IsValid() && meta.Inbound.Local.IsValid() {
+		if inbound := session.InboundFromContext(ctx); inbound != nil {
+			newInbound := *inbound
+			newInbound.Source = meta.Inbound.Source
+			newInbound.Local = meta.Inbound.Local
+			ctx = session.ContextWithInbound(ctx, &newInbound)
+		}
+	}
 	errors.LogInfo(ctx, "received request for ", meta.Target)
 	{
 		msg := &log.AccessMessage{
@@ -329,7 +337,7 @@ func (w *ServerWorker) handleStatusEnd(meta *FrameMetadata, reader *buf.Buffered
 
 func (w *ServerWorker) handleFrame(ctx context.Context, reader *buf.BufferedReader) error {
 	var meta FrameMetadata
-	err := meta.Unmarshal(reader)
+	err := meta.Unmarshal(reader, session.IsReverseMuxFromContext(ctx))
 	if err != nil {
 		return errors.New("failed to read metadata").Base(err)
 	}
@@ -340,7 +348,7 @@ func (w *ServerWorker) handleFrame(ctx context.Context, reader *buf.BufferedRead
 	case SessionStatusEnd:
 		err = w.handleStatusEnd(&meta, reader)
 	case SessionStatusNew:
-		err = w.handleStatusNew(ctx, &meta, reader)
+		err = w.handleStatusNew(session.ContextWithIsReverseMux(ctx, false), &meta, reader)
 	case SessionStatusKeep:
 		err = w.handleStatusKeep(&meta, reader)
 	default:

common/mux/writer.go

@@ -6,6 +6,7 @@ import (
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/common/protocol"
 	"github.com/xtls/xray-core/common/serial"
+	"github.com/xtls/xray-core/common/session"
 )
 
 type Writer struct {
@@ -16,9 +17,10 @@ type Writer struct {
 	hasError     bool
 	transferType protocol.TransferType
 	globalID     [8]byte
+	inbound      *session.Inbound
 }
 
-func NewWriter(id uint16, dest net.Destination, writer buf.Writer, transferType protocol.TransferType, globalID [8]byte) *Writer {
+func NewWriter(id uint16, dest net.Destination, writer buf.Writer, transferType protocol.TransferType, globalID [8]byte, inbound *session.Inbound) *Writer {
 	return &Writer{
 		id:           id,
 		dest:         dest,
@@ -26,6 +28,7 @@ func NewWriter(id uint16, dest net.Destination, writer buf.Writer, transferType
 		followup:     false,
 		transferType: transferType,
 		globalID:     globalID,
+		inbound:      inbound,
 	}
 }
 
@@ -43,6 +46,7 @@ func (w *Writer) getNextFrameMeta() FrameMetadata {
 		SessionID: w.id,
 		Target:    w.dest,
 		GlobalID:  w.globalID,
+		Inbound:   w.inbound,
 	}
 
 	if w.followup {

common/protocol/headers.go

@@ -73,7 +73,7 @@ type ResponseHeader struct {
 var (
 	// Keep in sync with crypto/tls/cipher_suites.go.
 	hasGCMAsmAMD64 = cpu.X86.HasAES && cpu.X86.HasPCLMULQDQ && cpu.X86.HasSSE41 && cpu.X86.HasSSSE3
-	hasGCMAsmARM64 = cpu.ARM64.HasAES && cpu.ARM64.HasPMULL
+	hasGCMAsmARM64 = (cpu.ARM64.HasAES && cpu.ARM64.HasPMULL) || (runtime.GOOS == "darwin" && runtime.GOARCH == "arm64")
 	hasGCMAsmS390X = cpu.S390X.HasAES && cpu.S390X.HasAESCTR && cpu.S390X.HasGHASH
 	hasGCMAsmPPC64 = runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le"
 

common/session/context.go

@@ -17,13 +17,13 @@ const (
 	inboundSessionKey         ctx.SessionKey = 1
 	outboundSessionKey        ctx.SessionKey = 2
 	contentSessionKey         ctx.SessionKey = 3
-	muxPreferredSessionKey    ctx.SessionKey = 4  // unused
+	isReverseMuxKey           ctx.SessionKey = 4  // is reverse mux
 	sockoptSessionKey         ctx.SessionKey = 5  // used by dokodemo to only receive sockopt.Mark
 	trackedConnectionErrorKey ctx.SessionKey = 6  // used by observer to get outbound error
 	dispatcherKey             ctx.SessionKey = 7  // used by ss2022 inbounds to get dispatcher
 	timeoutOnlyKey            ctx.SessionKey = 8  // mux context's child contexts to only cancel when its own traffic times out
 	allowedNetworkKey         ctx.SessionKey = 9  // muxcool server control incoming request tcp/udp
-	handlerSessionKey         ctx.SessionKey = 10 // outbound gets full handler
+	fullHandlerKey            ctx.SessionKey = 10 // outbound gets full handler
 	mitmAlpn11Key             ctx.SessionKey = 11 // used by TLS dialer
 	mitmServerNameKey         ctx.SessionKey = 12 // used by TLS dialer
 )
@@ -75,25 +75,21 @@ func ContentFromContext(ctx context.Context) *Content {
 	return nil
 }
 
-// ContextWithMuxPreferred returns a new context with the given bool
+func ContextWithIsReverseMux(ctx context.Context, isReverseMux bool) context.Context {
-func ContextWithMuxPreferred(ctx context.Context, forced bool) context.Context {
+	return context.WithValue(ctx, isReverseMuxKey, isReverseMux)
-	return context.WithValue(ctx, muxPreferredSessionKey, forced)
 }
 
-// MuxPreferredFromContext returns value in this context, or false if not contained.
+func IsReverseMuxFromContext(ctx context.Context) bool {
-func MuxPreferredFromContext(ctx context.Context) bool {
+	if val, ok := ctx.Value(isReverseMuxKey).(bool); ok {
-	if val, ok := ctx.Value(muxPreferredSessionKey).(bool); ok {
 		return val
 	}
 	return false
 }
 
-// ContextWithSockopt returns a new context with Socket configs included
 func ContextWithSockopt(ctx context.Context, s *Sockopt) context.Context {
 	return context.WithValue(ctx, sockoptSessionKey, s)
 }
 
-// SockoptFromContext returns Socket configs in this context, or nil if not contained.
 func SockoptFromContext(ctx context.Context) *Sockopt {
 	if sockopt, ok := ctx.Value(sockoptSessionKey).(*Sockopt); ok {
 		return sockopt
@@ -164,12 +160,12 @@ func AllowedNetworkFromContext(ctx context.Context) net.Network {
 	return net.Network_Unknown
 }
 
-func ContextWithHandler(ctx context.Context, handler outbound.Handler) context.Context {
+func ContextWithFullHandler(ctx context.Context, handler outbound.Handler) context.Context {
-	return context.WithValue(ctx, handlerSessionKey, handler)
+	return context.WithValue(ctx, fullHandlerKey, handler)
 }
 
-func HandlerFromContext(ctx context.Context) outbound.Handler {
+func FullHandlerFromContext(ctx context.Context) outbound.Handler {
-	if val, ok := ctx.Value(handlerSessionKey).(outbound.Handler); ok {
+	if val, ok := ctx.Value(fullHandlerKey).(outbound.Handler); ok {
 		return val
 	}
 	return nil

common/singbridge/pipe.go

@@ -4,8 +4,10 @@ import (
 	"context"
 	"io"
 	"net"
+	"time"
 
 	"github.com/sagernet/sing/common/bufio"
+	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/buf"
 	"github.com/xtls/xray-core/transport"
 )
@@ -33,8 +35,26 @@ func (w *PipeConnWrapper) Close() error {
 	return nil
 }
 
+// This Read implemented a timeout to avoid goroutine leak.
+// as a temporarily solution
 func (w *PipeConnWrapper) Read(b []byte) (n int, err error) {
-	return w.R.Read(b)
+	type readResult struct {
+		n   int
+		err error
+	}
+	c := make(chan readResult, 1)
+	go func() {
+		n, err := w.R.Read(b)
+		c <- readResult{n: n, err: err}
+	}()
+	select {
+	case result := <-c:
+		return result.n, result.err
+	case <-time.After(300 * time.Second):
+		common.Close(w.R)
+		common.Interrupt(w.R)
+		return 0, buf.ErrReadTimeout
+	}
 }
 
 func (w *PipeConnWrapper) Write(p []byte) (n int, err error) {

core/core.go

@@ -18,8 +18,8 @@ import (
 
 var (
 	Version_x byte = 25
-	Version_y byte = 9
+	Version_y byte = 10
-	Version_z byte = 11
+	Version_z byte = 15
 )
 
 var (

features/routing/dns/context.go

@@ -12,14 +12,19 @@ import (
 // ResolvableContext is an implementation of routing.Context, with domain resolving capability.
 type ResolvableContext struct {
 	routing.Context
-	dnsClient   dns.Client
+	dnsClient dns.Client
-	resolvedIPs []net.IP
+	cacheIPs  []net.IP
+	hasError  bool
 }
 
 // GetTargetIPs overrides original routing.Context's implementation.
 func (ctx *ResolvableContext) GetTargetIPs() []net.IP {
-	if len(ctx.resolvedIPs) > 0 {
+	if len(ctx.cacheIPs) > 0 {
-		return ctx.resolvedIPs
+		return ctx.cacheIPs
+	}
+
+	if ctx.hasError {
+		return nil
 	}
 
 	if domain := ctx.GetTargetDomain(); len(domain) != 0 {
@@ -29,16 +34,18 @@ func (ctx *ResolvableContext) GetTargetIPs() []net.IP {
 			FakeEnable: false,
 		})
 		if err == nil {
-			ctx.resolvedIPs = ips
+			ctx.cacheIPs = ips
 			return ips
 		}
 		errors.LogInfoInner(context.Background(), err, "resolve ip for ", domain)
 	}
 
 	if ips := ctx.Context.GetTargetIPs(); len(ips) != 0 {
+		ctx.cacheIPs = ips
 		return ips
 	}
 
+	ctx.hasError = true
 	return nil
 }
 

go.mod

@@ -11,23 +11,23 @@ require (
 	github.com/miekg/dns v1.1.68
 	github.com/pelletier/go-toml v1.9.5
 	github.com/pires/go-proxyproto v0.8.1
-	github.com/quic-go/quic-go v0.54.0
+	github.com/quic-go/quic-go v0.55.0
-	github.com/refraction-networking/utls v1.8.0
+	github.com/refraction-networking/utls v1.8.1
 	github.com/sagernet/sing v0.5.1
 	github.com/sagernet/sing-shadowsocks v0.2.7
 	github.com/seiflotfy/cuckoofilter v0.0.0-20240715131351-a2f2c23f1771
 	github.com/stretchr/testify v1.11.1
 	github.com/v2fly/ss-bloomring v0.0.0-20210312155135-28617310f63e
 	github.com/vishvananda/netlink v1.3.1
-	github.com/xtls/reality v0.0.0-20250904214705-431b6ff8c67c
+	github.com/xtls/reality v0.0.0-20251014195629-e4eec4520535
 	go4.org/netipx v0.0.0-20231129151722-fdeea329fbba
-	golang.org/x/crypto v0.42.0
+	golang.org/x/crypto v0.43.0
-	golang.org/x/net v0.44.0
+	golang.org/x/net v0.46.0
 	golang.org/x/sync v0.17.0
-	golang.org/x/sys v0.36.0
+	golang.org/x/sys v0.37.0
 	golang.zx2c4.com/wireguard v0.0.0-20231211153847-12269c276173
-	google.golang.org/grpc v1.75.1
+	google.golang.org/grpc v1.76.0
-	google.golang.org/protobuf v1.36.9
+	google.golang.org/protobuf v1.36.10
 	gvisor.dev/gvisor v0.0.0-20250428193742-2d800c3129d5
 	h12.io/socks v1.0.3
 	lukechampine.com/blake3 v1.4.1
@@ -46,13 +46,12 @@ require (
 	github.com/quic-go/qpack v0.5.1 // indirect
 	github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3 // indirect
 	github.com/vishvananda/netns v0.0.5 // indirect
-	go.uber.org/mock v0.5.0 // indirect
+	golang.org/x/mod v0.28.0 // indirect
-	golang.org/x/mod v0.27.0 // indirect
+	golang.org/x/text v0.30.0 // indirect
-	golang.org/x/text v0.29.0 // indirect
 	golang.org/x/time v0.7.0 // indirect
-	golang.org/x/tools v0.36.0 // indirect
+	golang.org/x/tools v0.37.0 // indirect
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20250707201910-8d1bb00bc6a7 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20250804133106-a7a43d27e69b // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -51,10 +51,10 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/quic-go/qpack v0.5.1 h1:giqksBPnT/HDtZ6VhtFKgoLOWmlyo9Ei6u9PqzIMbhI=
 github.com/quic-go/qpack v0.5.1/go.mod h1:+PC4XFrEskIVkcLzpEkbLqq1uCoxPhQuvK5rH1ZgaEg=
-github.com/quic-go/quic-go v0.54.0 h1:6s1YB9QotYI6Ospeiguknbp2Znb/jZYjZLRXn9kMQBg=
+github.com/quic-go/quic-go v0.55.0 h1:zccPQIqYCXDt5NmcEabyYvOnomjs8Tlwl7tISjJh9Mk=
-github.com/quic-go/quic-go v0.54.0/go.mod h1:e68ZEaCdyviluZmy44P6Iey98v/Wfz6HCjQEm+l8zTY=
+github.com/quic-go/quic-go v0.55.0/go.mod h1:DR51ilwU1uE164KuWXhinFcKWGlEjzys2l8zUl5Ss1U=
-github.com/refraction-networking/utls v1.8.0 h1:L38krhiTAyj9EeiQQa2sg+hYb4qwLCqdMcpZrRfbONE=
+github.com/refraction-networking/utls v1.8.1 h1:yNY1kapmQU8JeM1sSw2H2asfTIwWxIkrMJI0pRUOCAo=
-github.com/refraction-networking/utls v1.8.0/go.mod h1:jkSOEkLqn+S/jtpEHPOsVv/4V4EVnelwbMQl4vCWXAM=
+github.com/refraction-networking/utls v1.8.1/go.mod h1:jkSOEkLqn+S/jtpEHPOsVv/4V4EVnelwbMQl4vCWXAM=
 github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3 h1:f/FNXud6gA3MNr8meMVVGxhp+QBTqY91tM8HjEuMjGg=
 github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3/go.mod h1:HgjTstvQsPGkxUsCd2KWxErBblirPizecHcpD3ffK+s=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
@@ -75,8 +75,8 @@ github.com/vishvananda/netlink v1.3.1 h1:3AEMt62VKqz90r0tmNhog0r/PpWKmrEShJU0wJW
 github.com/vishvananda/netlink v1.3.1/go.mod h1:ARtKouGSTGchR8aMwmkzC0qiNPrrWO5JS/XMVl45+b4=
 github.com/vishvananda/netns v0.0.5 h1:DfiHV+j8bA32MFM7bfEunvT8IAqQ/NzSJHtcmW5zdEY=
 github.com/vishvananda/netns v0.0.5/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZlaprSwhNNJM=
-github.com/xtls/reality v0.0.0-20250904214705-431b6ff8c67c h1:LHLhQY3mKXSpTcQAkjFR4/6ar3rXjQryNeM7khK3AHU=
+github.com/xtls/reality v0.0.0-20251014195629-e4eec4520535 h1:nwobseOLLRtdbP6z7Z2aVI97u8ZptTgD1ofovhAKmeU=
-github.com/xtls/reality v0.0.0-20250904214705-431b6ff8c67c/go.mod h1:XxvnCCgBee4WWE0bc4E+a7wbk8gkJ/rS0vNVNtC5qp0=
+github.com/xtls/reality v0.0.0-20251014195629-e4eec4520535/go.mod h1:vbHCV/3VWUvy1oKvTxxWJRPEWSeR1sYgQHIh6u/JiZQ=
 github.com/yuin/goldmark v1.4.1/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
 go.opentelemetry.io/auto/sdk v1.1.0 h1:cH53jehLUN6UFLY71z+NDOiNJqDdPRaXzTel0sJySYA=
 go.opentelemetry.io/auto/sdk v1.1.0/go.mod h1:3wSPjt5PWp2RhlCcmmOial7AvC4DQqZb7a7wCow3W8A=
@@ -90,22 +90,22 @@ go.opentelemetry.io/otel/sdk/metric v1.37.0 h1:90lI228XrB9jCMuSdA0673aubgRobVZFh
 go.opentelemetry.io/otel/sdk/metric v1.37.0/go.mod h1:cNen4ZWfiD37l5NhS+Keb5RXVWZWpRE+9WyVCpbo5ps=
 go.opentelemetry.io/otel/trace v1.37.0 h1:HLdcFNbRQBE2imdSEgm/kwqmQj1Or1l/7bW6mxVK7z4=
 go.opentelemetry.io/otel/trace v1.37.0/go.mod h1:TlgrlQ+PtQO5XFerSPUYG0JSgGyryXewPGyayAWSBS0=
-go.uber.org/mock v0.5.0 h1:KAMbZvZPyBPWgD14IrIQ38QCyjwpvVVV6K/bHl1IwQU=
+go.uber.org/mock v0.5.2 h1:LbtPTcP8A5k9WPXj54PPPbjcI4Y6lhyOZXn+VS7wNko=
-go.uber.org/mock v0.5.0/go.mod h1:ge71pBPLYDk7QIi1LupWxdAykm7KIEFchiOqd6z7qMM=
+go.uber.org/mock v0.5.2/go.mod h1:wLlUxC2vVTPTaE3UD51E0BGOAElKrILxhVSDYQLld5o=
 go4.org/netipx v0.0.0-20231129151722-fdeea329fbba h1:0b9z3AuHCjxk0x/opv64kcgZLBseWJUpBw5I82+2U4M=
 go4.org/netipx v0.0.0-20231129151722-fdeea329fbba/go.mod h1:PLyyIXexvUFg3Owu6p/WfdlivPbZJsZdgWZlrGope/Y=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
-golang.org/x/crypto v0.42.0 h1:chiH31gIWm57EkTXpwnqf8qeuMUi0yekh6mT2AvFlqI=
+golang.org/x/crypto v0.43.0 h1:dduJYIi3A3KOfdGOHX8AVZ/jGiyPa3IbBozJ5kNuE04=
-golang.org/x/crypto v0.42.0/go.mod h1:4+rDnOTJhQCx2q7/j6rAN5XDw8kPjeaXEUR2eL94ix8=
+golang.org/x/crypto v0.43.0/go.mod h1:BFbav4mRNlXJL4wNeejLpWxB7wMbc79PdRGhWKncxR0=
 golang.org/x/mod v0.5.1/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
-golang.org/x/mod v0.27.0 h1:kb+q2PyFnEADO2IEF935ehFUXlWiNjJWtRNgBLSfbxQ=
+golang.org/x/mod v0.28.0 h1:gQBtGhjxykdjY9YhZpSlZIsbnaE2+PgjfLWUQTnoZ1U=
-golang.org/x/mod v0.27.0/go.mod h1:rWI627Fq0DEoudcK+MBkNkCe0EetEaDSwJJkCcjpazc=
+golang.org/x/mod v0.28.0/go.mod h1:yfB/L0NOf/kmEbXjzCPOx1iK1fRutOydrCMsqRhEBxI=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/net v0.44.0 h1:evd8IRDyfNBMBTTY5XRF1vaZlD+EmWx6x8PkhR04H/I=
+golang.org/x/net v0.46.0 h1:giFlY12I07fugqwPuWJi68oOnpfqFnJIJzaIIm2JVV4=
-golang.org/x/net v0.44.0/go.mod h1:ECOoLqd5U3Lhyeyo/QDCEVQ4sNgYsqvCZ722XogGieY=
+golang.org/x/net v0.46.0/go.mod h1:Q9BGdFy1y4nkUwiLvT5qtyhAnEHgnQ/zd8PfU6nc210=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
@@ -117,21 +117,21 @@ golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
+golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
-golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.37.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
+golang.org/x/text v0.30.0 h1:yznKA/E9zq54KzlzBEAWn1NXSQ8DIp/NYMy88xJjl4k=
-golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=
+golang.org/x/text v0.30.0/go.mod h1:yDdHFIX9t+tORqspjENWgzaCVXgk0yYnYuSZ8UzzBVM=
 golang.org/x/time v0.7.0 h1:ntUhktv3OPE6TgYxXWv9vKvUSJyIFJlyohwbkEwPrKQ=
 golang.org/x/time v0.7.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.8/go.mod h1:nABZi5QlRsZVlzPpHl034qft6wpY4eDcsTt5AaioBiU=
-golang.org/x/tools v0.36.0 h1:kWS0uv/zsvHEle1LbV5LE8QujrxB3wfQyxHfhOk0Qkg=
+golang.org/x/tools v0.37.0 h1:DVSRzp7FwePZW356yEAChSdNcQo6Nsp+fex1SUW09lE=
-golang.org/x/tools v0.36.0/go.mod h1:WBDiHKJK8YgLHlcQPYQzNCkUxUypCaa5ZegCVutKm+s=
+golang.org/x/tools v0.37.0/go.mod h1:MBN5QPQtLMHVdvsbtarmTNukZDdgwdwlO5qGacAzF0w=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
@@ -141,12 +141,12 @@ golang.zx2c4.com/wireguard v0.0.0-20231211153847-12269c276173 h1:/jFs0duh4rdb8uI
 golang.zx2c4.com/wireguard v0.0.0-20231211153847-12269c276173/go.mod h1:tkCQ4FQXmpAgYVh++1cq16/dH4QJtmvpRv19DWGAHSA=
 gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
 gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20250707201910-8d1bb00bc6a7 h1:pFyd6EwwL2TqFf8emdthzeX+gZE1ElRq3iM8pui4KBY=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20250804133106-a7a43d27e69b h1:zPKJod4w6F1+nRGDI9ubnXYhU9NSWoFAijkHkUXeTK8=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20250707201910-8d1bb00bc6a7/go.mod h1:qQ0YXyHHx3XkvlzUtpXDkS29lDSafHMZBAZDc03LQ3A=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20250804133106-a7a43d27e69b/go.mod h1:qQ0YXyHHx3XkvlzUtpXDkS29lDSafHMZBAZDc03LQ3A=
-google.golang.org/grpc v1.75.1 h1:/ODCNEuf9VghjgO3rqLcfg8fiOP0nSluljWFlDxELLI=
+google.golang.org/grpc v1.76.0 h1:UnVkv1+uMLYXoIz6o7chp59WfQUYA2ex/BXQ9rHZu7A=
-google.golang.org/grpc v1.75.1/go.mod h1:JtPAzKiq4v1xcAB2hydNlWI2RnF85XXcV0mhKXr2ecQ=
+google.golang.org/grpc v1.76.0/go.mod h1:Ju12QI8M6iQJtbcsV+awF5a4hfJMLi4X0JLo94ULZ6c=
-google.golang.org/protobuf v1.36.9 h1:w2gp2mA27hUeUzj9Ex9FBjsBm40zfaDtEWow293U7Iw=
+google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
-google.golang.org/protobuf v1.36.9/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
+google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

infra/conf/dns.go

@@ -16,19 +16,21 @@ import (
 )
 
 type NameServerConfig struct {
-	Address       *Address   `json:"address"`
+	Address         *Address   `json:"address"`
-	ClientIP      *Address   `json:"clientIp"`
+	ClientIP        *Address   `json:"clientIp"`
-	Port          uint16     `json:"port"`
+	Port            uint16     `json:"port"`
-	SkipFallback  bool       `json:"skipFallback"`
+	SkipFallback    bool       `json:"skipFallback"`
-	Domains       []string   `json:"domains"`
+	Domains         []string   `json:"domains"`
-	ExpectedIPs   StringList `json:"expectedIPs"`
+	ExpectedIPs     StringList `json:"expectedIPs"`
-	ExpectIPs     StringList `json:"expectIPs"`
+	ExpectIPs       StringList `json:"expectIPs"`
-	QueryStrategy string     `json:"queryStrategy"`
+	QueryStrategy   string     `json:"queryStrategy"`
-	Tag           string     `json:"tag"`
+	Tag             string     `json:"tag"`
-	TimeoutMs     uint64     `json:"timeoutMs"`
+	TimeoutMs       uint64     `json:"timeoutMs"`
-	DisableCache  bool       `json:"disableCache"`
+	DisableCache    bool       `json:"disableCache"`
-	FinalQuery    bool       `json:"finalQuery"`
+	ServeStale      bool       `json:"serveStale"`
-	UnexpectedIPs StringList `json:"unexpectedIPs"`
+	ServeExpiredTTL uint32     `json:"serveExpiredTTL"`
+	FinalQuery      bool       `json:"finalQuery"`
+	UnexpectedIPs   StringList `json:"unexpectedIPs"`
 }
 
 // UnmarshalJSON implements encoding/json.Unmarshaler.UnmarshalJSON
@@ -40,19 +42,21 @@ func (c *NameServerConfig) UnmarshalJSON(data []byte) error {
 	}
 
 	var advanced struct {
-		Address       *Address   `json:"address"`
+		Address         *Address   `json:"address"`
-		ClientIP      *Address   `json:"clientIp"`
+		ClientIP        *Address   `json:"clientIp"`
-		Port          uint16     `json:"port"`
+		Port            uint16     `json:"port"`
-		SkipFallback  bool       `json:"skipFallback"`
+		SkipFallback    bool       `json:"skipFallback"`
-		Domains       []string   `json:"domains"`
+		Domains         []string   `json:"domains"`
-		ExpectedIPs   StringList `json:"expectedIPs"`
+		ExpectedIPs     StringList `json:"expectedIPs"`
-		ExpectIPs     StringList `json:"expectIPs"`
+		ExpectIPs       StringList `json:"expectIPs"`
-		QueryStrategy string     `json:"queryStrategy"`
+		QueryStrategy   string     `json:"queryStrategy"`
-		Tag           string     `json:"tag"`
+		Tag             string     `json:"tag"`
-		TimeoutMs     uint64     `json:"timeoutMs"`
+		TimeoutMs       uint64     `json:"timeoutMs"`
-		DisableCache  bool       `json:"disableCache"`
+		DisableCache    bool       `json:"disableCache"`
-		FinalQuery    bool       `json:"finalQuery"`
+		ServeStale      bool       `json:"serveStale"`
-		UnexpectedIPs StringList `json:"unexpectedIPs"`
+		ServeExpiredTTL uint32     `json:"serveExpiredTTL"`
+		FinalQuery      bool       `json:"finalQuery"`
+		UnexpectedIPs   StringList `json:"unexpectedIPs"`
 	}
 	if err := json.Unmarshal(data, &advanced); err == nil {
 		c.Address = advanced.Address
@@ -66,6 +70,8 @@ func (c *NameServerConfig) UnmarshalJSON(data []byte) error {
 		c.Tag = advanced.Tag
 		c.TimeoutMs = advanced.TimeoutMs
 		c.DisableCache = advanced.DisableCache
+		c.ServeStale = advanced.ServeStale
+		c.ServeExpiredTTL = advanced.ServeExpiredTTL
 		c.FinalQuery = advanced.FinalQuery
 		c.UnexpectedIPs = advanced.UnexpectedIPs
 		return nil
@@ -173,6 +179,8 @@ func (c *NameServerConfig) Build() (*dns.NameServer, error) {
 		Tag:               c.Tag,
 		TimeoutMs:         c.TimeoutMs,
 		DisableCache:      c.DisableCache,
+		ServeStale:        c.ServeStale,
+		ServeExpiredTTL:   &c.ServeExpiredTTL,
 		FinalQuery:        c.FinalQuery,
 		UnexpectedGeoip:   unexpectedGeoipList,
 		ActUnprior:        actUnprior,
@@ -194,6 +202,8 @@ type DNSConfig struct {
 	Tag                    string              `json:"tag"`
 	QueryStrategy          string              `json:"queryStrategy"`
 	DisableCache           bool                `json:"disableCache"`
+	ServeStale             bool                `json:"serveStale"`
+	ServeExpiredTTL        uint32              `json:"serveExpiredTTL"`
 	DisableFallback        bool                `json:"disableFallback"`
 	DisableFallbackIfMatch bool                `json:"disableFallbackIfMatch"`
 	UseSystemHosts         bool                `json:"useSystemHosts"`
@@ -391,6 +401,8 @@ func (c *DNSConfig) Build() (*dns.Config, error) {
 	config := &dns.Config{
 		Tag:                    c.Tag,
 		DisableCache:           c.DisableCache,
+		ServeStale:             c.ServeStale,
+		ServeExpiredTTL:        c.ServeExpiredTTL,
 		DisableFallback:        c.DisableFallback,
 		DisableFallbackIfMatch: c.DisableFallbackIfMatch,
 		QueryStrategy:          resolveQueryStrategy(c.QueryStrategy),

infra/conf/dns_test.go

@@ -20,7 +20,7 @@ func TestDNSConfigParsing(t *testing.T) {
 			return config.Build()
 		}
 	}
-
+	expectedServeExpiredTTL := uint32(172800)
 	runMultiTestCase(t, []TestCase{
 		{
 			Input: `{
@@ -28,7 +28,9 @@ func TestDNSConfigParsing(t *testing.T) {
 					"address": "8.8.8.8",
 					"port": 5353,
 					"skipFallback": true,
-					"domains": ["domain:example.com"]
+					"domains": ["domain:example.com"],
+					"serveStale": true,
+					"serveExpiredTTL": 172800
 				}],
 				"hosts": {
 					"domain:example.com": "google.com",
@@ -40,6 +42,8 @@ func TestDNSConfigParsing(t *testing.T) {
 				"clientIp": "10.0.0.1",
 				"queryStrategy": "UseIPv4",
 				"disableCache": true,
+				"serveStale": false,
+				"serveExpiredTTL": 86400,
 				"disableFallback": true
 			}`,
 			Parser: parserCreator(),
@@ -68,6 +72,8 @@ func TestDNSConfigParsing(t *testing.T) {
 								Size: 1,
 							},
 						},
+						ServeStale:      true,
+						ServeExpiredTTL: &expectedServeExpiredTTL,
 					},
 				},
 				StaticHosts: []*dns.Config_HostMapping{
@@ -100,6 +106,8 @@ func TestDNSConfigParsing(t *testing.T) {
 				ClientIp:        []byte{10, 0, 0, 1},
 				QueryStrategy:   dns.QueryStrategy_USE_IP4,
 				DisableCache:    true,
+				ServeStale:      false,
+				ServeExpiredTTL: 86400,
 				DisableFallback: true,
 			},
 		},

infra/conf/transport_internet.go

@@ -289,8 +289,8 @@ func (c *SplitHTTPConfig) Build() (proto.Message, error) {
 		return nil, errors.New("maxConnections cannot be specified together with maxConcurrency")
 	}
 	if c.Xmux == (XmuxConfig{}) {
-		c.Xmux.MaxConcurrency.From = 16
+		c.Xmux.MaxConcurrency.From = 1
-		c.Xmux.MaxConcurrency.To = 32
+		c.Xmux.MaxConcurrency.To = 1
 		c.Xmux.HMaxRequestTimes.From = 600
 		c.Xmux.HMaxRequestTimes.To = 900
 		c.Xmux.HMaxReusableSecs.From = 1800

main/confloader/external/external.go

@@ -2,6 +2,8 @@ package external
 
 import (
 	"bytes"
+	"context"
+	"net"
 	"io"
 	"net/http"
 	"net/url"
@@ -18,6 +20,9 @@ import (
 func ConfigLoader(arg string) (out io.Reader, err error) {
 	var data []byte
 	switch {
+	case strings.HasPrefix(arg, "http+unix://"):
+		data, err = FetchUnixSocketHTTPContent(arg)
+
 	case strings.HasPrefix(arg, "http://"), strings.HasPrefix(arg, "https://"):
 		data, err = FetchHTTPContent(arg)
 
@@ -70,6 +75,60 @@ func FetchHTTPContent(target string) ([]byte, error) {
 	return content, nil
 }
 
+// Format: http+unix:///path/to/socket.sock/api/endpoint
+func FetchUnixSocketHTTPContent(target string) ([]byte, error) {
+	path := strings.TrimPrefix(target, "http+unix://")
+	
+	if !strings.HasPrefix(path, "/") {
+		return nil, errors.New("unix socket path must be absolute")
+	}
+	
+	var socketPath, httpPath string
+	
+	sockIdx := strings.Index(path, ".sock")
+	if sockIdx != -1 {
+		socketPath = path[:sockIdx+5]
+		httpPath = path[sockIdx+5:]
+		if httpPath == "" {
+			httpPath = "/"
+		}
+	} else {
+		return nil, errors.New("cannot determine socket path, socket file should have .sock extension")
+	}
+	
+	if _, err := os.Stat(socketPath); err != nil {
+		return nil, errors.New("socket file not found: ", socketPath).Base(err)
+	}
+	
+	client := &http.Client{
+		Timeout: 30 * time.Second,
+		Transport: &http.Transport{
+			DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+				var d net.Dialer
+				return d.DialContext(ctx, "unix", socketPath)
+			},
+		},
+	}
+	defer client.CloseIdleConnections()
+	
+	resp, err := client.Get("http://localhost" + httpPath)
+	if err != nil {
+		return nil, errors.New("failed to fetch from unix socket: ", socketPath).Base(err)
+	}
+	defer resp.Body.Close()
+	
+	if resp.StatusCode != 200 {
+		return nil, errors.New("unexpected HTTP status code: ", resp.StatusCode)
+	}
+	
+	content, err := buf.ReadAllToBytes(resp.Body)
+	if err != nil {
+		return nil, errors.New("failed to read response").Base(err)
+	}
+	
+	return content, nil
+}
+
 func ExtConfigLoader(files []string, reader io.Reader) (io.Reader, error) {
 	buf, err := ctlcmd.Run(append([]string{"convert"}, files...), reader)
 	if err != nil {

proxy/vless/inbound/inbound.go

@@ -666,7 +666,7 @@ func (r *Reverse) Dispatch(ctx context.Context, link *transport.Link) {
 			link.Reader = &buf.EndpointOverrideReader{Reader: link.Reader, Dest: ob.Target.Address, OriginalDest: ob.OriginalTarget.Address}
 			link.Writer = &buf.EndpointOverrideWriter{Writer: link.Writer, Dest: ob.Target.Address, OriginalDest: ob.OriginalTarget.Address}
 		}
-		r.client.Dispatch(ctx, link)
+		r.client.Dispatch(session.ContextWithIsReverseMux(ctx, true), link)
 	}
 }
 

proxy/vless/outbound/outbound.go

@@ -89,8 +89,11 @@ func New(ctx context.Context, config *Config) (*Handler, error) {
 		handler.reverse = &Reverse{
 			tag:        a.Reverse.Tag,
 			dispatcher: v.GetFeature(routing.DispatcherType()).(routing.Dispatcher),
-			ctx:        ctx,
+			ctx: session.ContextWithInbound(ctx, &session.Inbound{
-			handler:    handler,
+				Tag:  a.Reverse.Tag,
+				User: handler.server.User, // TODO: email
+			}),
+			handler: handler,
 		}
 		handler.reverse.monitorTask = &task.Periodic{
 			Execute:  handler.reverse.monitor,
@@ -198,7 +201,7 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
 			}
 		case protocol.RequestCommandMux:
 			fallthrough // let server break Mux connections that contain TCP requests
-		case protocol.RequestCommandTCP:
+		case protocol.RequestCommandTCP, protocol.RequestCommandRvs:
 			var t reflect.Type
 			var p uintptr
 			if commonConn, ok := conn.(*encryption.CommonConn); ok {
@@ -223,6 +226,8 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
 			r, _ := t.FieldByName("rawInput")
 			input = (*bytes.Reader)(unsafe.Pointer(p + i.Offset))
 			rawInput = (*bytes.Buffer)(unsafe.Pointer(p + r.Offset))
+		default:
+			panic("unknown VLESS request command")
 		}
 	default:
 		ob.CanSpliceCopy = 3
@@ -395,7 +400,7 @@ func (r *Reverse) monitor() error {
 			Tag:        r.tag,
 			Dispatcher: r.dispatcher,
 		}
-		worker, err := mux.NewServerWorker(r.ctx, w, link1)
+		worker, err := mux.NewServerWorker(session.ContextWithIsReverseMux(r.ctx, true), w, link1)
 		if err != nil {
 			errors.LogWarningInner(r.ctx, err, "failed to create mux server worker")
 			return nil
@@ -406,7 +411,7 @@ func (r *Reverse) monitor() error {
 			ctx := session.ContextWithOutbounds(r.ctx, []*session.Outbound{{
 				Target: net.Destination{Address: net.DomainAddress("v1.rvs.cool")},
 			}})
-			r.handler.Process(ctx, link2, session.HandlerFromContext(ctx).(*proxyman.Handler))
+			r.handler.Process(ctx, link2, session.FullHandlerFromContext(ctx).(*proxyman.Handler))
 			common.Interrupt(reader1)
 			common.Interrupt(reader2)
 		}()

transport/internet/reality/reality.go

@@ -75,8 +75,7 @@ func (c *UConn) HandshakeAddress() net.Address {
 func (c *UConn) VerifyPeerCertificate(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error {
 	if c.Config.Show {
 		localAddr := c.LocalAddr().String()
-		curveID := *(*utls.CurveID)(unsafe.Pointer(reflect.ValueOf(c).Elem().FieldByName("curveID").UnsafeAddr()))
+		fmt.Printf("REALITY localAddr: %v\tis using X25519MLKEM768 for TLS' communication: %v\n", localAddr, c.HandshakeState.ServerHello.ServerShare.Group == utls.X25519MLKEM768)
-		fmt.Printf("REALITY localAddr: %v\tis using X25519MLKEM768 for TLS' communication: %v\n", localAddr, curveID == utls.X25519MLKEM768)
 		fmt.Printf("REALITY localAddr: %v\tis using ML-DSA-65 for cert's extra verification: %v\n", localAddr, len(c.Config.Mldsa65Verify) > 0)
 	}
 	p, _ := reflect.TypeOf(c.Conn).Elem().FieldByName("peerCertificates")