Fix DNS query log

app/dispatcher/default.go

@@ -309,15 +309,10 @@ func sniffer(ctx context.Context, cReader *cachedReader, metadataOnly bool) (Sni
 func (d *DefaultDispatcher) routedDispatch(ctx context.Context, link *transport.Link, destination net.Destination) {
 	var handler outbound.Handler
 
-	skipRoutePick := false
-	if content := session.ContentFromContext(ctx); content != nil {
-		skipRoutePick = content.SkipRoutePick
-	}
-
 	routingLink := routing_session.AsRoutingContext(ctx)
 	inTag := routingLink.GetInboundTag()
 	isPickRoute := false
-	if d.router != nil && !skipRoutePick {
+	if d.router != nil {
 		if route, err := d.router.PickRoute(routingLink); err == nil {
 			outTag := route.GetOutboundTag()
 			isPickRoute = true

app/dns/config.go

@@ -0,0 +1,63 @@
+package dns
+
+import (
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/common/strmatcher"
+	"github.com/xtls/xray-core/common/uuid"
+)
+
+var typeMap = map[DomainMatchingType]strmatcher.Type{
+	DomainMatchingType_Full:      strmatcher.Full,
+	DomainMatchingType_Subdomain: strmatcher.Domain,
+	DomainMatchingType_Keyword:   strmatcher.Substr,
+	DomainMatchingType_Regex:     strmatcher.Regex,
+}
+
+// References:
+// https://www.iana.org/assignments/special-use-domain-names/special-use-domain-names.xhtml
+// https://unix.stackexchange.com/questions/92441/whats-the-difference-between-local-home-and-lan
+var localTLDsAndDotlessDomains = []*NameServer_PriorityDomain{
+	{Type: DomainMatchingType_Regex, Domain: "^[^.]+$"}, // This will only match domains without any dot
+	{Type: DomainMatchingType_Subdomain, Domain: "local"},
+	{Type: DomainMatchingType_Subdomain, Domain: "localdomain"},
+	{Type: DomainMatchingType_Subdomain, Domain: "localhost"},
+	{Type: DomainMatchingType_Subdomain, Domain: "lan"},
+	{Type: DomainMatchingType_Subdomain, Domain: "home.arpa"},
+	{Type: DomainMatchingType_Subdomain, Domain: "example"},
+	{Type: DomainMatchingType_Subdomain, Domain: "invalid"},
+	{Type: DomainMatchingType_Subdomain, Domain: "test"},
+}
+
+var localTLDsAndDotlessDomainsRule = &NameServer_OriginalRule{
+	Rule: "geosite:private",
+	Size: uint32(len(localTLDsAndDotlessDomains)),
+}
+
+func toStrMatcher(t DomainMatchingType, domain string) (strmatcher.Matcher, error) {
+	strMType, f := typeMap[t]
+	if !f {
+		return nil, newError("unknown mapping type", t).AtWarning()
+	}
+	matcher, err := strMType.New(domain)
+	if err != nil {
+		return nil, newError("failed to create str matcher").Base(err)
+	}
+	return matcher, nil
+}
+
+func toNetIP(addrs []net.Address) ([]net.IP, error) {
+	ips := make([]net.IP, 0, len(addrs))
+	for _, addr := range addrs {
+		if addr.Family().IsIP() {
+			ips = append(ips, addr.IP())
+		} else {
+			return nil, newError("Failed to convert address", addr, "to Net IP.").AtWarning()
+		}
+	}
+	return ips, nil
+}
+
+func generateRandomTag() string {
+	id := uuid.New()
+	return "xray.system." + id.String()
+}

app/dns/config.pb.go

@@ -1,13 +1,12 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.25.0
-// 	protoc        v3.14.0
+// 	protoc-gen-go v1.26.0
+// 	protoc        v3.15.8
 // source: app/dns/config.proto
 
 package dns
 
 import (
-	proto "github.com/golang/protobuf/proto"
 	router "github.com/xtls/xray-core/app/router"
 	net "github.com/xtls/xray-core/common/net"
 	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
@@ -23,10 +22,6 @@ const (
 	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
 )
 
-// This is a compile-time assertion that a sufficiently up-to-date version
-// of the legacy proto package is being used.
-const _ = proto.ProtoPackageIsVersion4
-
 type DomainMatchingType int32
 
 const (
@@ -79,12 +74,112 @@ func (DomainMatchingType) EnumDescriptor() ([]byte, []int) {
 	return file_app_dns_config_proto_rawDescGZIP(), []int{0}
 }
 
+type QueryStrategy int32
+
+const (
+	QueryStrategy_USE_IP  QueryStrategy = 0
+	QueryStrategy_USE_IP4 QueryStrategy = 1
+	QueryStrategy_USE_IP6 QueryStrategy = 2
+)
+
+// Enum value maps for QueryStrategy.
+var (
+	QueryStrategy_name = map[int32]string{
+		0: "USE_IP",
+		1: "USE_IP4",
+		2: "USE_IP6",
+	}
+	QueryStrategy_value = map[string]int32{
+		"USE_IP":  0,
+		"USE_IP4": 1,
+		"USE_IP6": 2,
+	}
+)
+
+func (x QueryStrategy) Enum() *QueryStrategy {
+	p := new(QueryStrategy)
+	*p = x
+	return p
+}
+
+func (x QueryStrategy) String() string {
+	return protoimpl.X.EnumStringOf(x.Descriptor(), protoreflect.EnumNumber(x))
+}
+
+func (QueryStrategy) Descriptor() protoreflect.EnumDescriptor {
+	return file_app_dns_config_proto_enumTypes[1].Descriptor()
+}
+
+func (QueryStrategy) Type() protoreflect.EnumType {
+	return &file_app_dns_config_proto_enumTypes[1]
+}
+
+func (x QueryStrategy) Number() protoreflect.EnumNumber {
+	return protoreflect.EnumNumber(x)
+}
+
+// Deprecated: Use QueryStrategy.Descriptor instead.
+func (QueryStrategy) EnumDescriptor() ([]byte, []int) {
+	return file_app_dns_config_proto_rawDescGZIP(), []int{1}
+}
+
+type CacheStrategy int32
+
+const (
+	CacheStrategy_Cache_ALL     CacheStrategy = 0
+	CacheStrategy_Cache_NOERROR CacheStrategy = 1
+	CacheStrategy_Cache_DISABLE CacheStrategy = 2
+)
+
+// Enum value maps for CacheStrategy.
+var (
+	CacheStrategy_name = map[int32]string{
+		0: "Cache_ALL",
+		1: "Cache_NOERROR",
+		2: "Cache_DISABLE",
+	}
+	CacheStrategy_value = map[string]int32{
+		"Cache_ALL":     0,
+		"Cache_NOERROR": 1,
+		"Cache_DISABLE": 2,
+	}
+)
+
+func (x CacheStrategy) Enum() *CacheStrategy {
+	p := new(CacheStrategy)
+	*p = x
+	return p
+}
+
+func (x CacheStrategy) String() string {
+	return protoimpl.X.EnumStringOf(x.Descriptor(), protoreflect.EnumNumber(x))
+}
+
+func (CacheStrategy) Descriptor() protoreflect.EnumDescriptor {
+	return file_app_dns_config_proto_enumTypes[2].Descriptor()
+}
+
+func (CacheStrategy) Type() protoreflect.EnumType {
+	return &file_app_dns_config_proto_enumTypes[2]
+}
+
+func (x CacheStrategy) Number() protoreflect.EnumNumber {
+	return protoreflect.EnumNumber(x)
+}
+
+// Deprecated: Use CacheStrategy.Descriptor instead.
+func (CacheStrategy) EnumDescriptor() ([]byte, []int) {
+	return file_app_dns_config_proto_rawDescGZIP(), []int{2}
+}
+
 type NameServer struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
 	unknownFields protoimpl.UnknownFields
 
 	Address           *net.Endpoint                `protobuf:"bytes,1,opt,name=address,proto3" json:"address,omitempty"`
+	ClientIp          []byte                       `protobuf:"bytes,5,opt,name=client_ip,json=clientIp,proto3" json:"client_ip,omitempty"`
+	SkipFallback      bool                         `protobuf:"varint,6,opt,name=skipFallback,proto3" json:"skipFallback,omitempty"`
 	PrioritizedDomain []*NameServer_PriorityDomain `protobuf:"bytes,2,rep,name=prioritized_domain,json=prioritizedDomain,proto3" json:"prioritized_domain,omitempty"`
 	Geoip             []*router.GeoIP              `protobuf:"bytes,3,rep,name=geoip,proto3" json:"geoip,omitempty"`
 	OriginalRules     []*NameServer_OriginalRule   `protobuf:"bytes,4,rep,name=original_rules,json=originalRules,proto3" json:"original_rules,omitempty"`
@@ -129,6 +224,20 @@ func (x *NameServer) GetAddress() *net.Endpoint {
 	return nil
 }
 
+func (x *NameServer) GetClientIp() []byte {
+	if x != nil {
+		return x.ClientIp
+	}
+	return nil
+}
+
+func (x *NameServer) GetSkipFallback() bool {
+	if x != nil {
+		return x.SkipFallback
+	}
+	return false
+}
+
 func (x *NameServer) GetPrioritizedDomain() []*NameServer_PriorityDomain {
 	if x != nil {
 		return x.PrioritizedDomain
@@ -174,6 +283,10 @@ type Config struct {
 	StaticHosts []*Config_HostMapping `protobuf:"bytes,4,rep,name=static_hosts,json=staticHosts,proto3" json:"static_hosts,omitempty"`
 	// Tag is the inbound tag of DNS client.
 	Tag string `protobuf:"bytes,6,opt,name=tag,proto3" json:"tag,omitempty"`
+	// DisableCache disables DNS cache
+	CacheStrategy   CacheStrategy `protobuf:"varint,8,opt,name=cache_strategy,json=cacheStrategy,proto3,enum=xray.app.dns.CacheStrategy" json:"cache_strategy,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"`
 }
 
 func (x *Config) Reset() {
@@ -252,6 +365,27 @@ func (x *Config) GetTag() string {
 	return ""
 }
 
+func (x *Config) GetCacheStrategy() CacheStrategy {
+	if x != nil {
+		return x.CacheStrategy
+	}
+	return CacheStrategy_Cache_ALL
+}
+
+func (x *Config) GetQueryStrategy() QueryStrategy {
+	if x != nil {
+		return x.QueryStrategy
+	}
+	return QueryStrategy_USE_IP
+}
+
+func (x *Config) GetDisableFallback() bool {
+	if x != nil {
+		return x.DisableFallback
+	}
+	return false
+}
+
 type NameServer_PriorityDomain struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -371,8 +505,7 @@ type Config_HostMapping struct {
 	Domain string             `protobuf:"bytes,2,opt,name=domain,proto3" json:"domain,omitempty"`
 	Ip     [][]byte           `protobuf:"bytes,3,rep,name=ip,proto3" json:"ip,omitempty"`
 	// ProxiedDomain indicates the mapped domain has the same IP address on this
-	// domain. Xray will use this domain for IP queries. This field is only
-	// effective if ip is empty.
+	// domain. Xray will use this domain for IP queries.
 	ProxiedDomain string `protobuf:"bytes,4,opt,name=proxied_domain,json=proxiedDomain,proto3" json:"proxied_domain,omitempty"`
 }
 
@@ -446,77 +579,101 @@ var file_app_dns_config_proto_rawDesc = []byte{
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 }
 
 var (
@@ -531,37 +688,41 @@ func file_app_dns_config_proto_rawDescGZIP() []byte {
 	return file_app_dns_config_proto_rawDescData
 }
 
-var file_app_dns_config_proto_enumTypes = make([]protoimpl.EnumInfo, 1)
+var file_app_dns_config_proto_enumTypes = make([]protoimpl.EnumInfo, 3)
 var file_app_dns_config_proto_msgTypes = make([]protoimpl.MessageInfo, 6)
 var file_app_dns_config_proto_goTypes = []interface{}{
 	(DomainMatchingType)(0),           // 0: xray.app.dns.DomainMatchingType
-	(*NameServer)(nil),                // 1: xray.app.dns.NameServer
-	(*Config)(nil),                    // 2: xray.app.dns.Config
-	(*NameServer_PriorityDomain)(nil), // 3: xray.app.dns.NameServer.PriorityDomain
-	(*NameServer_OriginalRule)(nil),   // 4: xray.app.dns.NameServer.OriginalRule
-	nil,                               // 5: xray.app.dns.Config.HostsEntry
-	(*Config_HostMapping)(nil),        // 6: xray.app.dns.Config.HostMapping
-	(*net.Endpoint)(nil),              // 7: xray.common.net.Endpoint
-	(*router.GeoIP)(nil),              // 8: xray.app.router.GeoIP
-	(*net.IPOrDomain)(nil),            // 9: xray.common.net.IPOrDomain
+	(QueryStrategy)(0),                // 1: xray.app.dns.QueryStrategy
+	(CacheStrategy)(0),                // 2: xray.app.dns.CacheStrategy
+	(*NameServer)(nil),                // 3: xray.app.dns.NameServer
+	(*Config)(nil),                    // 4: xray.app.dns.Config
+	(*NameServer_PriorityDomain)(nil), // 5: xray.app.dns.NameServer.PriorityDomain
+	(*NameServer_OriginalRule)(nil),   // 6: xray.app.dns.NameServer.OriginalRule
+	nil,                               // 7: xray.app.dns.Config.HostsEntry
+	(*Config_HostMapping)(nil),        // 8: xray.app.dns.Config.HostMapping
+	(*net.Endpoint)(nil),              // 9: xray.common.net.Endpoint
+	(*router.GeoIP)(nil),              // 10: xray.app.router.GeoIP
+	(*net.IPOrDomain)(nil),            // 11: xray.common.net.IPOrDomain
 }
 var file_app_dns_config_proto_depIdxs = []int32{
-	7,  // 0: xray.app.dns.NameServer.address:type_name -> xray.common.net.Endpoint
-	3,  // 1: xray.app.dns.NameServer.prioritized_domain:type_name -> xray.app.dns.NameServer.PriorityDomain
-	8,  // 2: xray.app.dns.NameServer.geoip:type_name -> xray.app.router.GeoIP
-	4,  // 3: xray.app.dns.NameServer.original_rules:type_name -> xray.app.dns.NameServer.OriginalRule
-	7,  // 4: xray.app.dns.Config.NameServers:type_name -> xray.common.net.Endpoint
-	1,  // 5: xray.app.dns.Config.name_server:type_name -> xray.app.dns.NameServer
-	5,  // 6: xray.app.dns.Config.Hosts:type_name -> xray.app.dns.Config.HostsEntry
-	6,  // 7: xray.app.dns.Config.static_hosts:type_name -> xray.app.dns.Config.HostMapping
-	0,  // 8: xray.app.dns.NameServer.PriorityDomain.type:type_name -> xray.app.dns.DomainMatchingType
-	9,  // 9: xray.app.dns.Config.HostsEntry.value:type_name -> xray.common.net.IPOrDomain
-	0,  // 10: xray.app.dns.Config.HostMapping.type:type_name -> xray.app.dns.DomainMatchingType
-	11, // [11:11] is the sub-list for method output_type
-	11, // [11:11] is the sub-list for method input_type
-	11, // [11:11] is the sub-list for extension type_name
-	11, // [11:11] is the sub-list for extension extendee
-	0,  // [0:11] is the sub-list for field type_name
+	9,  // 0: xray.app.dns.NameServer.address:type_name -> xray.common.net.Endpoint
+	5,  // 1: xray.app.dns.NameServer.prioritized_domain:type_name -> xray.app.dns.NameServer.PriorityDomain
+	10, // 2: xray.app.dns.NameServer.geoip:type_name -> xray.app.router.GeoIP
+	6,  // 3: xray.app.dns.NameServer.original_rules:type_name -> xray.app.dns.NameServer.OriginalRule
+	9,  // 4: xray.app.dns.Config.NameServers:type_name -> xray.common.net.Endpoint
+	3,  // 5: xray.app.dns.Config.name_server:type_name -> xray.app.dns.NameServer
+	7,  // 6: xray.app.dns.Config.Hosts:type_name -> xray.app.dns.Config.HostsEntry
+	8,  // 7: xray.app.dns.Config.static_hosts:type_name -> xray.app.dns.Config.HostMapping
+	2,  // 8: xray.app.dns.Config.cache_strategy:type_name -> xray.app.dns.CacheStrategy
+	1,  // 9: xray.app.dns.Config.query_strategy:type_name -> xray.app.dns.QueryStrategy
+	0,  // 10: xray.app.dns.NameServer.PriorityDomain.type:type_name -> xray.app.dns.DomainMatchingType
+	11, // 11: xray.app.dns.Config.HostsEntry.value:type_name -> xray.common.net.IPOrDomain
+	0,  // 12: xray.app.dns.Config.HostMapping.type:type_name -> xray.app.dns.DomainMatchingType
+	13, // [13:13] is the sub-list for method output_type
+	13, // [13:13] is the sub-list for method input_type
+	13, // [13:13] is the sub-list for extension type_name
+	13, // [13:13] is the sub-list for extension extendee
+	0,  // [0:13] is the sub-list for field type_name
 }
 
 func init() { file_app_dns_config_proto_init() }
@@ -636,7 +797,7 @@ func file_app_dns_config_proto_init() {
 		File: protoimpl.DescBuilder{
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_app_dns_config_proto_rawDesc,
-			NumEnums:      1,
+			NumEnums:      3,
 			NumMessages:   6,
 			NumExtensions: 0,
 			NumServices:   0,

app/dns/config.proto

@@ -12,6 +12,8 @@ import "app/router/config.proto";
 
 message NameServer {
   xray.common.net.Endpoint address = 1;
+  bytes client_ip = 5;
+  bool skipFallback = 6;
 
   message PriorityDomain {
     DomainMatchingType type = 1;
@@ -35,6 +37,18 @@ enum DomainMatchingType {
   Regex = 3;
 }
 
+enum QueryStrategy {
+  USE_IP = 0;
+  USE_IP4 = 1;
+  USE_IP6 = 2;
+}
+
+enum CacheStrategy {
+  Cache_ALL = 0;
+  Cache_NOERROR = 1;
+  Cache_DISABLE = 2;
+}
+
 message Config {
   // Nameservers used by this DNS. Only traditional UDP servers are support at
   // the moment. A special value 'localhost' as a domain address can be set to
@@ -59,8 +73,7 @@ message Config {
     repeated bytes ip = 3;
 
     // ProxiedDomain indicates the mapped domain has the same IP address on this
-    // domain. Xray will use this domain for IP queries. This field is only
-    // effective if ip is empty.
+    // domain. Xray will use this domain for IP queries.
     string proxied_domain = 4;
   }
 
@@ -70,4 +83,11 @@ message Config {
   string tag = 6;
 
   reserved 7;
+
+  // DisableCache disables DNS cache
+  CacheStrategy cache_strategy = 8;
+
+  QueryStrategy query_strategy = 9;
+
+  bool disableFallback = 10;
 }

app/dns/dns.go

@@ -2,3 +2,312 @@
 package dns
 
 //go:generate go run github.com/xtls/xray-core/common/errors/errorgen
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/xtls/xray-core/app/router"
+	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/errors"
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/common/session"
+	"github.com/xtls/xray-core/common/strmatcher"
+	"github.com/xtls/xray-core/features"
+	"github.com/xtls/xray-core/features/dns"
+)
+
+// DNS is a DNS rely server.
+type DNS struct {
+	sync.Mutex
+	tag             string
+	cacheStrategy   CacheStrategy
+	disableFallback bool
+	ipOption        *dns.IPOption
+	hosts           *StaticHosts
+	clients         []*Client
+	ctx             context.Context
+	domainMatcher   strmatcher.IndexMatcher
+	matcherInfos    []DomainMatcherInfo
+}
+
+// DomainMatcherInfo contains information attached to index returned by Server.domainMatcher
+type DomainMatcherInfo struct {
+	clientIdx     uint16
+	domainRuleIdx uint16
+}
+
+// New creates a new DNS server with given configuration.
+func New(ctx context.Context, config *Config) (*DNS, error) {
+	var tag string
+	if len(config.Tag) > 0 {
+		tag = config.Tag
+	} else {
+		tag = generateRandomTag()
+	}
+
+	var clientIP net.IP
+	switch len(config.ClientIp) {
+	case 0, net.IPv4len, net.IPv6len:
+		clientIP = net.IP(config.ClientIp)
+	default:
+		return nil, newError("unexpected client IP length ", len(config.ClientIp))
+	}
+
+	var ipOption *dns.IPOption
+	switch config.QueryStrategy {
+	case QueryStrategy_USE_IP:
+		ipOption = &dns.IPOption{
+			IPv4Enable: true,
+			IPv6Enable: true,
+			FakeEnable: false,
+		}
+	case QueryStrategy_USE_IP4:
+		ipOption = &dns.IPOption{
+			IPv4Enable: true,
+			IPv6Enable: false,
+			FakeEnable: false,
+		}
+	case QueryStrategy_USE_IP6:
+		ipOption = &dns.IPOption{
+			IPv4Enable: false,
+			IPv6Enable: true,
+			FakeEnable: false,
+		}
+	}
+
+	hosts, err := NewStaticHosts(config.StaticHosts, config.Hosts)
+	if err != nil {
+		return nil, newError("failed to create hosts").Base(err)
+	}
+
+	clients := []*Client{}
+	domainRuleCount := 0
+	for _, ns := range config.NameServer {
+		domainRuleCount += len(ns.PrioritizedDomain)
+	}
+
+	// MatcherInfos is ensured to cover the maximum index domainMatcher could return, where matcher's index starts from 1
+	matcherInfos := make([]DomainMatcherInfo, domainRuleCount+1)
+	domainMatcher := &strmatcher.MatcherGroup{}
+	geoipContainer := router.GeoIPMatcherContainer{}
+
+	for _, endpoint := range config.NameServers {
+		features.PrintDeprecatedFeatureWarning("simple DNS server")
+		client, err := NewSimpleClient(ctx, endpoint, clientIP)
+		if err != nil {
+			return nil, newError("failed to create client").Base(err)
+		}
+		clients = append(clients, client)
+	}
+
+	for _, ns := range config.NameServer {
+		clientIdx := len(clients)
+		updateDomain := func(domainRule strmatcher.Matcher, originalRuleIdx int, matcherInfos []DomainMatcherInfo) error {
+			midx := domainMatcher.Add(domainRule)
+			matcherInfos[midx] = DomainMatcherInfo{
+				clientIdx:     uint16(clientIdx),
+				domainRuleIdx: uint16(originalRuleIdx),
+			}
+			return nil
+		}
+
+		myClientIP := clientIP
+		switch len(ns.ClientIp) {
+		case net.IPv4len, net.IPv6len:
+			myClientIP = net.IP(ns.ClientIp)
+		}
+		client, err := NewClient(ctx, ns, myClientIP, geoipContainer, &matcherInfos, updateDomain)
+		if err != nil {
+			return nil, newError("failed to create client").Base(err)
+		}
+		clients = append(clients, client)
+	}
+
+	// If there is no DNS client in config, add a `localhost` DNS client
+	if len(clients) == 0 {
+		clients = append(clients, NewLocalDNSClient())
+	}
+
+	return &DNS{
+		tag:             tag,
+		hosts:           hosts,
+		ipOption:        ipOption,
+		clients:         clients,
+		ctx:             ctx,
+		domainMatcher:   domainMatcher,
+		matcherInfos:    matcherInfos,
+		cacheStrategy:   config.CacheStrategy,
+		disableFallback: config.DisableFallback,
+	}, nil
+}
+
+// Type implements common.HasType.
+func (*DNS) Type() interface{} {
+	return dns.ClientType()
+}
+
+// Start implements common.Runnable.
+func (s *DNS) Start() error {
+	return nil
+}
+
+// Close implements common.Closable.
+func (s *DNS) Close() error {
+	return nil
+}
+
+// IsOwnLink implements proxy.dns.ownLinkVerifier
+func (s *DNS) IsOwnLink(ctx context.Context) bool {
+	inbound := session.InboundFromContext(ctx)
+	return inbound != nil && inbound.Tag == s.tag
+}
+
+// LookupIP implements dns.Client.
+func (s *DNS) LookupIP(domain string) ([]net.IP, error) {
+	return s.lookupIPInternal(domain, s.ipOption.Copy())
+}
+
+// LookupOptions implements dns.Client.
+func (s *DNS) LookupOptions(domain string, opts ...dns.Option) ([]net.IP, error) {
+	opt := s.ipOption.Copy()
+	for _, o := range opts {
+		if o != nil {
+			o(opt)
+		}
+	}
+
+	return s.lookupIPInternal(domain, opt)
+}
+
+// LookupIPv4 implements dns.IPv4Lookup.
+func (s *DNS) LookupIPv4(domain string) ([]net.IP, error) {
+	return s.lookupIPInternal(domain, &dns.IPOption{
+		IPv4Enable: true,
+	})
+}
+
+// LookupIPv6 implements dns.IPv6Lookup.
+func (s *DNS) LookupIPv6(domain string) ([]net.IP, error) {
+	return s.lookupIPInternal(domain, &dns.IPOption{
+		IPv6Enable: true,
+	})
+}
+
+func (s *DNS) lookupIPInternal(domain string, option *dns.IPOption) ([]net.IP, error) {
+	if domain == "" {
+		return nil, newError("empty domain name")
+	}
+	if isQuery(option) {
+		return nil, newError("empty option: Impossible.").AtWarning()
+	}
+
+	// Normalize the FQDN form query
+	if strings.HasSuffix(domain, ".") {
+		domain = domain[:len(domain)-1]
+	}
+
+	// Static host lookup
+	switch addrs := s.hosts.Lookup(domain, option); {
+	case addrs == nil: // Domain not recorded in static host
+		break
+	case len(addrs) == 0: // Domain recorded, but no valid IP returned (e.g. IPv4 address with only IPv6 enabled)
+		return nil, dns.ErrEmptyResponse
+	case len(addrs) == 1 && addrs[0].Family().IsDomain(): // Domain replacement
+		newError("domain replaced: ", domain, " -> ", addrs[0].Domain()).WriteToLog()
+		domain = addrs[0].Domain()
+	default:
+		// Successfully found ip records in static host.
+		// Skip hosts mapping result in FakeDNS query.
+		if isIPQuery(option) {
+			newError("returning ", len(addrs), " IP(s) for domain ", domain, " -> ", addrs).WriteToLog()
+			return toNetIP(addrs)
+		}
+	}
+
+	// Name servers lookup
+	errs := []error{}
+	ctx := session.ContextWithInbound(s.ctx, &session.Inbound{Tag: s.tag})
+	for _, client := range s.sortClients(domain, option) {
+		ips, err := client.QueryIP(ctx, domain, *option, s.cacheStrategy)
+		if len(ips) > 0 {
+			return ips, nil
+		}
+		if err != nil {
+			newError("failed to lookup ip for domain ", domain, " at server ", client.Name()).Base(err).WriteToLog()
+			errs = append(errs, err)
+		}
+		if err != context.Canceled && err != context.DeadlineExceeded && err != errExpectedIPNonMatch {
+			return nil, err
+		}
+	}
+
+	return nil, newError("returning nil for domain ", domain).Base(errors.Combine(errs...))
+}
+
+func (s *DNS) sortClients(domain string, option *dns.IPOption) []*Client {
+	clients := make([]*Client, 0, len(s.clients))
+	clientUsed := make([]bool, len(s.clients))
+	clientNames := make([]string, 0, len(s.clients))
+	domainRules := []string{}
+
+	defer func() {
+		if len(domainRules) > 0 {
+			newError("domain ", domain, " matches following rules: ", domainRules).AtDebug().WriteToLog()
+		}
+		if len(clientNames) > 0 {
+			newError("domain ", domain, " will use DNS in order: ", clientNames).AtDebug().WriteToLog()
+		}
+		if len(clients) == 0 {
+			clients = append(clients, s.clients[0])
+			clientNames = append(clientNames, s.clients[0].Name())
+			newError("domain ", domain, " will use the first DNS: ", clientNames).AtDebug().WriteToLog()
+		}
+	}()
+
+	// Priority domain matching
+	for _, match := range s.domainMatcher.Match(domain) {
+		info := s.matcherInfos[match]
+		client := s.clients[info.clientIdx]
+		domainRule := client.domains[info.domainRuleIdx]
+		if !canQueryOnClient(option, client) {
+			newError("skipping the client " + client.Name()).AtDebug().WriteToLog()
+			continue
+		}
+		domainRules = append(domainRules, fmt.Sprintf("%s(DNS idx:%d)", domainRule, info.clientIdx))
+		if clientUsed[info.clientIdx] {
+			continue
+		}
+		clientUsed[info.clientIdx] = true
+		clients = append(clients, client)
+		clientNames = append(clientNames, client.Name())
+	}
+
+	if !s.disableFallback {
+		// Default round-robin query
+		for idx, client := range s.clients {
+			if clientUsed[idx] || client.skipFallback {
+				continue
+			}
+
+			if !canQueryOnClient(option, client) {
+				newError("skipping the client " + client.Name()).AtDebug().WriteToLog()
+				continue
+			}
+
+			clientUsed[idx] = true
+			clients = append(clients, client)
+			clientNames = append(clientNames, client.Name())
+		}
+	}
+
+	return clients
+}
+
+func init() {
+	common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
+		return New(ctx, config.(*Config))
+	}))
+}

app/dns/dns_test.go

@@ -154,11 +154,7 @@ func TestUDPServerSubnet(t *testing.T) {
 
 	client := v.GetFeature(feature_dns.ClientType()).(feature_dns.Client)
 
-	ips, err := client.LookupIP("google.com", feature_dns.IPOption{
-		IPv4Enable: true,
-		IPv6Enable: true,
-		FakeEnable: false,
-	})
+	ips, err := client.LookupIP("google.com")
 	if err != nil {
 		t.Fatal("unexpected error: ", err)
 	}
@@ -213,11 +209,7 @@ func TestUDPServer(t *testing.T) {
 	client := v.GetFeature(feature_dns.ClientType()).(feature_dns.Client)
 
 	{
-		ips, err := client.LookupIP("google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -228,11 +220,7 @@ func TestUDPServer(t *testing.T) {
 	}
 
 	{
-		ips, err := client.LookupIP("facebook.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("facebook.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -243,11 +231,7 @@ func TestUDPServer(t *testing.T) {
 	}
 
 	{
-		_, err := client.LookupIP("notexist.google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		_, err := client.LookupIP("notexist.google.com")
 		if err == nil {
 			t.Fatal("nil error")
 		}
@@ -257,11 +241,8 @@ func TestUDPServer(t *testing.T) {
 	}
 
 	{
-		ips, err := client.LookupIP("ipv4only.google.com", feature_dns.IPOption{
-			IPv4Enable: false,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		clientv6 := client.(feature_dns.IPv6Lookup)
+		ips, err := clientv6.LookupIPv6("ipv4only.google.com")
 		if err != feature_dns.ErrEmptyResponse {
 			t.Fatal("error: ", err)
 		}
@@ -273,11 +254,7 @@ func TestUDPServer(t *testing.T) {
 	dnsServer.Shutdown()
 
 	{
-		ips, err := client.LookupIP("google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -354,11 +331,7 @@ func TestPrioritizedDomain(t *testing.T) {
 	startTime := time.Now()
 
 	{
-		ips, err := client.LookupIP("google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -417,12 +390,9 @@ func TestUDPServerIPv6(t *testing.T) {
 	common.Must(err)
 
 	client := v.GetFeature(feature_dns.ClientType()).(feature_dns.Client)
+	client6 := client.(feature_dns.IPv6Lookup)
 	{
-		ips, err := client.LookupIP("ipv6.google.com", feature_dns.IPOption{
-			IPv4Enable: false,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client6.LookupIPv6("ipv6.google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -485,11 +455,7 @@ func TestStaticHostDomain(t *testing.T) {
 	client := v.GetFeature(feature_dns.ClientType()).(feature_dns.Client)
 
 	{
-		ips, err := client.LookupIP("example.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("example.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -596,11 +562,7 @@ func TestIPMatch(t *testing.T) {
 	startTime := time.Now()
 
 	{
-		ips, err := client.LookupIP("google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -719,11 +681,7 @@ func TestLocalDomain(t *testing.T) {
 	startTime := time.Now()
 
 	{ // Will match dotless:
-		ips, err := client.LookupIP("hostname", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("hostname")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -734,11 +692,7 @@ func TestLocalDomain(t *testing.T) {
 	}
 
 	{ // Will match domain:local
-		ips, err := client.LookupIP("hostname.local", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("hostname.local")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -749,11 +703,7 @@ func TestLocalDomain(t *testing.T) {
 	}
 
 	{ // Will match static ip
-		ips, err := client.LookupIP("hostnamestatic", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("hostnamestatic")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -764,11 +714,7 @@ func TestLocalDomain(t *testing.T) {
 	}
 
 	{ // Will match domain replacing
-		ips, err := client.LookupIP("hostnamealias", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("hostnamealias")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -779,11 +725,7 @@ func TestLocalDomain(t *testing.T) {
 	}
 
 	{ // Will match dotless:localhost, but not expectIPs: 127.0.0.2, 127.0.0.3, then matches at dotless:
-		ips, err := client.LookupIP("localhost", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("localhost")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -794,11 +736,7 @@ func TestLocalDomain(t *testing.T) {
 	}
 
 	{ // Will match dotless:localhost, and expectIPs: 127.0.0.2, 127.0.0.3
-		ips, err := client.LookupIP("localhost-a", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("localhost-a")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -809,11 +747,7 @@ func TestLocalDomain(t *testing.T) {
 	}
 
 	{ // Will match dotless:localhost, and expectIPs: 127.0.0.2, 127.0.0.3
-		ips, err := client.LookupIP("localhost-b", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("localhost-b")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -824,11 +758,7 @@ func TestLocalDomain(t *testing.T) {
 	}
 
 	{ // Will match dotless:
-		ips, err := client.LookupIP("Mijia Cloud", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("Mijia Cloud")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -990,11 +920,7 @@ func TestMultiMatchPrioritizedDomain(t *testing.T) {
 	startTime := time.Now()
 
 	{ // Will match server 1,2 and server 1 returns expected ip
-		ips, err := client.LookupIP("google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -1005,11 +931,8 @@ func TestMultiMatchPrioritizedDomain(t *testing.T) {
 	}
 
 	{ // Will match server 1,2 and server 1 returns unexpected ip, then server 2 returns expected one
-		ips, err := client.LookupIP("ipv6.google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: false,
-			FakeEnable: false,
-		})
+		clientv4 := client.(feature_dns.IPv4Lookup)
+		ips, err := clientv4.LookupIPv4("ipv6.google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -1020,11 +943,7 @@ func TestMultiMatchPrioritizedDomain(t *testing.T) {
 	}
 
 	{ // Will match server 3,1,2 and server 3 returns expected one
-		ips, err := client.LookupIP("api.google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("api.google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}
@@ -1035,11 +954,7 @@ func TestMultiMatchPrioritizedDomain(t *testing.T) {
 	}
 
 	{ // Will match server 4,3,1,2 and server 4 returns expected one
-		ips, err := client.LookupIP("v2.api.google.com", feature_dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := client.LookupIP("v2.api.google.com")
 		if err != nil {
 			t.Fatal("unexpected error: ", err)
 		}

app/dns/hosts.go

@@ -14,25 +14,6 @@ type StaticHosts struct {
 	matchers *strmatcher.MatcherGroup
 }
 
-var typeMap = map[DomainMatchingType]strmatcher.Type{
-	DomainMatchingType_Full:      strmatcher.Full,
-	DomainMatchingType_Subdomain: strmatcher.Domain,
-	DomainMatchingType_Keyword:   strmatcher.Substr,
-	DomainMatchingType_Regex:     strmatcher.Regex,
-}
-
-func toStrMatcher(t DomainMatchingType, domain string) (strmatcher.Matcher, error) {
-	strMType, f := typeMap[t]
-	if !f {
-		return nil, newError("unknown mapping type", t).AtWarning()
-	}
-	matcher, err := strMType.New(domain)
-	if err != nil {
-		return nil, newError("failed to create str matcher").Base(err)
-	}
-	return matcher, nil
-}
-
 // NewStaticHosts creates a new StaticHosts instance.
 func NewStaticHosts(hosts []*Config_HostMapping, legacy map[string]*net.IPOrDomain) (*StaticHosts, error) {
 	g := new(strmatcher.MatcherGroup)
@@ -66,6 +47,9 @@ func NewStaticHosts(hosts []*Config_HostMapping, legacy map[string]*net.IPOrDoma
 		id := g.Add(matcher)
 		ips := make([]net.Address, 0, len(mapping.Ip)+1)
 		switch {
+		case len(mapping.ProxiedDomain) > 0:
+			ips = append(ips, net.DomainAddress(mapping.ProxiedDomain))
+
 		case len(mapping.Ip) > 0:
 			for _, ip := range mapping.Ip {
 				addr := net.IPAddress(ip)
@@ -75,49 +59,56 @@ func NewStaticHosts(hosts []*Config_HostMapping, legacy map[string]*net.IPOrDoma
 				ips = append(ips, addr)
 			}
 
-		case len(mapping.ProxiedDomain) > 0:
-			ips = append(ips, net.DomainAddress(mapping.ProxiedDomain))
-
 		default:
 			return nil, newError("neither IP address nor proxied domain specified for domain: ", mapping.Domain).AtWarning()
 		}
 
-		// Special handling for localhost IPv6. This is a dirty workaround as JSON config supports only single IP mapping.
-		if len(ips) == 1 && ips[0] == net.LocalHostIP {
-			ips = append(ips, net.LocalHostIPv6)
-		}
-
 		sh.ips[id] = ips
 	}
 
 	return sh, nil
 }
 
-func filterIP(ips []net.Address, option dns.IPOption) []net.Address {
+func filterIP(ips []net.Address, option *dns.IPOption) []net.Address {
 	filtered := make([]net.Address, 0, len(ips))
 	for _, ip := range ips {
 		if (ip.Family().IsIPv4() && option.IPv4Enable) || (ip.Family().IsIPv6() && option.IPv6Enable) {
 			filtered = append(filtered, ip)
 		}
 	}
-	if len(filtered) == 0 {
-		return nil
-	}
 	return filtered
 }
 
-// LookupIP returns IP address for the given domain, if exists in this StaticHosts.
-func (h *StaticHosts) LookupIP(domain string, option dns.IPOption) []net.Address {
-	indices := h.matchers.Match(domain)
-	if len(indices) == 0 {
-		return nil
-	}
-	ips := []net.Address{}
-	for _, id := range indices {
+func (h *StaticHosts) lookupInternal(domain string) []net.Address {
+	var ips []net.Address
+	for _, id := range h.matchers.Match(domain) {
 		ips = append(ips, h.ips[id]...)
 	}
 	if len(ips) == 1 && ips[0].Family().IsDomain() {
 		return ips
 	}
-	return filterIP(ips, option)
+	return ips
+}
+
+func (h *StaticHosts) lookup(domain string, option *dns.IPOption, maxDepth int) []net.Address {
+	switch addrs := h.lookupInternal(domain); {
+	case len(addrs) == 0: // Not recorded in static hosts, return nil
+		return nil
+	case len(addrs) == 1 && addrs[0].Family().IsDomain(): // Try to unwrap domain
+		newError("found replaced domain: ", domain, " -> ", addrs[0].Domain(), ". Try to unwrap it").AtDebug().WriteToLog()
+		if maxDepth > 0 {
+			unwrapped := h.lookup(addrs[0].Domain(), option, maxDepth-1)
+			if unwrapped != nil {
+				return unwrapped
+			}
+		}
+		return addrs
+	default: // IP record found, return a non-nil IP array
+		return filterIP(addrs, option)
+	}
+}
+
+// Lookup returns IP addresses or proxied domain for the given domain, if exists in this StaticHosts.
+func (h *StaticHosts) Lookup(domain string, option *dns.IPOption) []net.Address {
+	return h.lookup(domain, option, 5)
 }

app/dns/hosts_test.go

@@ -20,6 +20,20 @@ func TestStaticHosts(t *testing.T) {
 				{1, 1, 1, 1},
 			},
 		},
+		{
+			Type:   DomainMatchingType_Full,
+			Domain: "proxy.example.com",
+			Ip: [][]byte{
+				{1, 2, 3, 4},
+				{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
+			},
+			ProxiedDomain: "another-proxy.example.com",
+		},
+		{
+			Type:          DomainMatchingType_Full,
+			Domain:        "proxy2.example.com",
+			ProxiedDomain: "proxy.example.com",
+		},
 		{
 			Type:   DomainMatchingType_Subdomain,
 			Domain: "example.cn",
@@ -32,6 +46,7 @@ func TestStaticHosts(t *testing.T) {
 			Domain: "baidu.com",
 			Ip: [][]byte{
 				{127, 0, 0, 1},
+				{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
 			},
 		},
 	}
@@ -40,7 +55,7 @@ func TestStaticHosts(t *testing.T) {
 	common.Must(err)
 
 	{
-		ips := hosts.LookupIP("example.com", dns.IPOption{
+		ips := hosts.Lookup("example.com", &dns.IPOption{
 			IPv4Enable: true,
 			IPv6Enable: true,
 		})
@@ -53,7 +68,33 @@ func TestStaticHosts(t *testing.T) {
 	}
 
 	{
-		ips := hosts.LookupIP("www.example.cn", dns.IPOption{
+		domain := hosts.Lookup("proxy.example.com", &dns.IPOption{
+			IPv4Enable: true,
+			IPv6Enable: false,
+		})
+		if len(domain) != 1 {
+			t.Error("expect 1 domain, but got ", len(domain))
+		}
+		if diff := cmp.Diff(domain[0].Domain(), "another-proxy.example.com"); diff != "" {
+			t.Error(diff)
+		}
+	}
+
+	{
+		domain := hosts.Lookup("proxy2.example.com", &dns.IPOption{
+			IPv4Enable: true,
+			IPv6Enable: false,
+		})
+		if len(domain) != 1 {
+			t.Error("expect 1 domain, but got ", len(domain))
+		}
+		if diff := cmp.Diff(domain[0].Domain(), "another-proxy.example.com"); diff != "" {
+			t.Error(diff)
+		}
+	}
+
+	{
+		ips := hosts.Lookup("www.example.cn", &dns.IPOption{
 			IPv4Enable: true,
 			IPv6Enable: true,
 		})
@@ -66,7 +107,7 @@ func TestStaticHosts(t *testing.T) {
 	}
 
 	{
-		ips := hosts.LookupIP("baidu.com", dns.IPOption{
+		ips := hosts.Lookup("baidu.com", &dns.IPOption{
 			IPv4Enable: false,
 			IPv6Enable: true,
 		})

app/dns/nameserver.go

@@ -2,40 +2,211 @@ package dns
 
 import (
 	"context"
+	"net/url"
+	"strings"
+	"time"
 
+	"github.com/xtls/xray-core/app/router"
+	"github.com/xtls/xray-core/common/errors"
 	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/common/strmatcher"
+	core "github.com/xtls/xray-core/core"
 	"github.com/xtls/xray-core/features/dns"
-	"github.com/xtls/xray-core/features/dns/localdns"
+	"github.com/xtls/xray-core/features/routing"
 )
 
-// Client is the interface for DNS client.
-type Client interface {
+// Server is the interface for Name Server.
+type Server interface {
 	// Name of the Client.
 	Name() string
-
 	// QueryIP sends IP queries to its configured server.
-	QueryIP(ctx context.Context, domain string, option dns.IPOption) ([]net.IP, error)
+	QueryIP(ctx context.Context, domain string, clientIP net.IP, option dns.IPOption, cs CacheStrategy) ([]net.IP, error)
 }
 
-type LocalNameServer struct {
-	client *localdns.Client
+// Client is the interface for DNS client.
+type Client struct {
+	server       Server
+	clientIP     net.IP
+	skipFallback bool
+	domains      []string
+	expectIPs    []*router.GeoIPMatcher
 }
 
-func (s *LocalNameServer) QueryIP(_ context.Context, domain string, option dns.IPOption) ([]net.IP, error) {
-	if option.IPv4Enable || option.IPv6Enable {
-		return s.client.LookupIP(domain, option)
+var errExpectedIPNonMatch = errors.New("expectIPs not match")
+
+// NewServer creates a name server object according to the network destination url.
+func NewServer(dest net.Destination, dispatcher routing.Dispatcher) (Server, error) {
+	if address := dest.Address; address.Family().IsDomain() {
+		u, err := url.Parse(address.Domain())
+		if err != nil {
+			return nil, err
+		}
+		switch {
+		case strings.EqualFold(u.String(), "localhost"):
+			return NewLocalNameServer(), nil
+		case strings.EqualFold(u.Scheme, "https"): // DOH Remote mode
+			return NewDoHNameServer(u, dispatcher)
+		case strings.EqualFold(u.Scheme, "https+local"): // DOH Local mode
+			return NewDoHLocalNameServer(u), nil
+		case strings.EqualFold(u.Scheme, "quic+local"): // DNS-over-QUIC Local mode
+			return NewQUICNameServer(u)
+		case strings.EqualFold(u.String(), "fakedns"):
+			return NewFakeDNSServer(), nil
+		}
+	}
+	if dest.Network == net.Network_Unknown {
+		dest.Network = net.Network_UDP
+	}
+	if dest.Network == net.Network_UDP { // UDP classic DNS mode
+		return NewClassicNameServer(dest, dispatcher), nil
+	}
+	return nil, newError("No available name server could be created from ", dest).AtWarning()
+}
+
+// NewClient creates a DNS client managing a name server with client IP, domain rules and expected IPs.
+func NewClient(ctx context.Context, ns *NameServer, clientIP net.IP, container router.GeoIPMatcherContainer, matcherInfos *[]DomainMatcherInfo, updateDomainRule func(strmatcher.Matcher, int, []DomainMatcherInfo) error) (*Client, error) {
+	client := &Client{}
+
+	err := core.RequireFeatures(ctx, func(dispatcher routing.Dispatcher) error {
+		// Create a new server for each client for now
+		server, err := NewServer(ns.Address.AsDestination(), dispatcher)
+		if err != nil {
+			return newError("failed to create nameserver").Base(err).AtWarning()
 		}
 
-	return nil, newError("neither IPv4 nor IPv6 is enabled")
-}
-
-func (s *LocalNameServer) Name() string {
-	return "localhost"
-}
-
-func NewLocalNameServer() *LocalNameServer {
-	newError("DNS: created localhost client").AtInfo().WriteToLog()
-	return &LocalNameServer{
-		client: localdns.New(),
+		// Priotize local domains with specific TLDs or without any dot to local DNS
+		if _, isLocalDNS := server.(*LocalNameServer); isLocalDNS {
+			ns.PrioritizedDomain = append(ns.PrioritizedDomain, localTLDsAndDotlessDomains...)
+			ns.OriginalRules = append(ns.OriginalRules, localTLDsAndDotlessDomainsRule)
+			// The following lines is a solution to avoid core panics（rule index out of range） when setting `localhost` DNS client in config.
+			// Because the `localhost` DNS client will apend len(localTLDsAndDotlessDomains) rules into matcherInfos to match `geosite:private` default rule.
+			// But `matcherInfos` has no enough length to add rules, which leads to core panics (rule index out of range).
+			// To avoid this, the length of `matcherInfos` must be equal to the expected, so manually append it with Golang default zero value first for later modification.
+			for i := 0; i < len(localTLDsAndDotlessDomains); i++ {
+				*matcherInfos = append(*matcherInfos, DomainMatcherInfo{
+					clientIdx:     uint16(0),
+					domainRuleIdx: uint16(0),
+				})
 			}
+		}
+
+		// Establish domain rules
+		var rules []string
+		ruleCurr := 0
+		ruleIter := 0
+		for _, domain := range ns.PrioritizedDomain {
+			domainRule, err := toStrMatcher(domain.Type, domain.Domain)
+			if err != nil {
+				return newError("failed to create prioritized domain").Base(err).AtWarning()
+			}
+			originalRuleIdx := ruleCurr
+			if ruleCurr < len(ns.OriginalRules) {
+				rule := ns.OriginalRules[ruleCurr]
+				if ruleCurr >= len(rules) {
+					rules = append(rules, rule.Rule)
+				}
+				ruleIter++
+				if ruleIter >= int(rule.Size) {
+					ruleIter = 0
+					ruleCurr++
+				}
+			} else { // No original rule, generate one according to current domain matcher (majorly for compatibility with tests)
+				rules = append(rules, domainRule.String())
+				ruleCurr++
+			}
+			err = updateDomainRule(domainRule, originalRuleIdx, *matcherInfos)
+			if err != nil {
+				return newError("failed to create prioritized domain").Base(err).AtWarning()
+			}
+		}
+
+		// Establish expected IPs
+		var matchers []*router.GeoIPMatcher
+		for _, geoip := range ns.Geoip {
+			matcher, err := container.Add(geoip)
+			if err != nil {
+				return newError("failed to create ip matcher").Base(err).AtWarning()
+			}
+			matchers = append(matchers, matcher)
+		}
+
+		if len(clientIP) > 0 {
+			switch ns.Address.Address.GetAddress().(type) {
+			case *net.IPOrDomain_Domain:
+				newError("DNS: client ", ns.Address.Address.GetDomain(), " uses clientIP ", clientIP.String()).AtInfo().WriteToLog()
+			case *net.IPOrDomain_Ip:
+				newError("DNS: client ", ns.Address.Address.GetIp(), " uses clientIP ", clientIP.String()).AtInfo().WriteToLog()
+			}
+		}
+
+		client.server = server
+		client.clientIP = clientIP
+		client.domains = rules
+		client.expectIPs = matchers
+		return nil
+	})
+	return client, err
+}
+
+// NewSimpleClient creates a DNS client with a simple destination.
+func NewSimpleClient(ctx context.Context, endpoint *net.Endpoint, clientIP net.IP) (*Client, error) {
+	client := &Client{}
+	err := core.RequireFeatures(ctx, func(dispatcher routing.Dispatcher) error {
+		server, err := NewServer(endpoint.AsDestination(), dispatcher)
+		if err != nil {
+			return newError("failed to create nameserver").Base(err).AtWarning()
+		}
+		client.server = server
+		client.clientIP = clientIP
+		return nil
+	})
+
+	if len(clientIP) > 0 {
+		switch endpoint.Address.GetAddress().(type) {
+		case *net.IPOrDomain_Domain:
+			newError("DNS: client ", endpoint.Address.GetDomain(), " uses clientIP ", clientIP.String()).AtInfo().WriteToLog()
+		case *net.IPOrDomain_Ip:
+			newError("DNS: client ", endpoint.Address.GetIp(), " uses clientIP ", clientIP.String()).AtInfo().WriteToLog()
+		}
+	}
+
+	return client, err
+}
+
+// Name returns the server name the client manages.
+func (c *Client) Name() string {
+	return c.server.Name()
+}
+
+// QueryIP send DNS query to the name server with the client's IP.
+func (c *Client) QueryIP(ctx context.Context, domain string, option dns.IPOption, cs CacheStrategy) ([]net.IP, error) {
+	ctx, cancel := context.WithTimeout(ctx, 4*time.Second)
+	ips, err := c.server.QueryIP(ctx, domain, c.clientIP, option, cs)
+	cancel()
+
+	if err != nil {
+		return ips, err
+	}
+	return c.MatchExpectedIPs(domain, ips)
+}
+
+// MatchExpectedIPs matches queried domain IPs with expected IPs and returns matched ones.
+func (c *Client) MatchExpectedIPs(domain string, ips []net.IP) ([]net.IP, error) {
+	if len(c.expectIPs) == 0 {
+		return ips, nil
+	}
+	newIps := []net.IP{}
+	for _, ip := range ips {
+		for _, matcher := range c.expectIPs {
+			if matcher.Match(ip) {
+				newIps = append(newIps, ip)
+				break
+			}
+		}
+	}
+	if len(newIps) == 0 {
+		return nil, errExpectedIPNonMatch
+	}
+	newError("domain ", domain, " expectIPs ", newIps, " matched at server ", c.Name()).AtDebug().WriteToLog()
+	return newIps, nil
 }

app/dns/nameserver_doh.go

@@ -42,10 +42,10 @@ type DoHNameServer struct {
 	name       string
 }
 
-// NewDoHNameServer creates DOH client object for remote resolving
-func NewDoHNameServer(url *url.URL, dispatcher routing.Dispatcher, clientIP net.IP) (*DoHNameServer, error) {
+// NewDoHNameServer creates DOH server object for remote resolving
+func NewDoHNameServer(url *url.URL, dispatcher routing.Dispatcher) (*DoHNameServer, error) {
 	newError("DNS: created Remote DOH client for ", url.String()).AtInfo().WriteToLog()
-	s := baseDOHNameServer(url, "DOH", clientIP)
+	s := baseDOHNameServer(url, "DOH")
 
 	s.dispatcher = dispatcher
 	tr := &http.Transport{
@@ -104,9 +104,9 @@ func NewDoHNameServer(url *url.URL, dispatcher routing.Dispatcher, clientIP net.
 }
 
 // NewDoHLocalNameServer creates DOH client object for local resolving
-func NewDoHLocalNameServer(url *url.URL, clientIP net.IP) *DoHNameServer {
+func NewDoHLocalNameServer(url *url.URL) *DoHNameServer {
 	url.Scheme = "https"
-	s := baseDOHNameServer(url, "DOHL", clientIP)
+	s := baseDOHNameServer(url, "DOHL")
 	tr := &http.Transport{
 		IdleConnTimeout:   90 * time.Second,
 		ForceAttemptHTTP2: true,
@@ -136,10 +136,9 @@ func NewDoHLocalNameServer(url *url.URL, clientIP net.IP) *DoHNameServer {
 	return s
 }
 
-func baseDOHNameServer(url *url.URL, prefix string, clientIP net.IP) *DoHNameServer {
+func baseDOHNameServer(url *url.URL, prefix string) *DoHNameServer {
 	s := &DoHNameServer{
 		ips:    make(map[string]record),
-		clientIP: clientIP,
 		pub:    pubsub.NewService(),
 		name:   prefix + "//" + url.Host,
 		dohURL: url.String(),
@@ -152,7 +151,7 @@ func baseDOHNameServer(url *url.URL, prefix string, clientIP net.IP) *DoHNameSer
 	return s
 }
 
-// Name returns client name
+// Name implements Server.
 func (s *DoHNameServer) Name() string {
 	return s.name
 }
@@ -235,7 +234,7 @@ func (s *DoHNameServer) newReqID() uint16 {
 	return uint16(atomic.AddUint32(&s.reqID, 1))
 }
 
-func (s *DoHNameServer) sendQuery(ctx context.Context, domain string, option dns_feature.IPOption) {
+func (s *DoHNameServer) sendQuery(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption) {
 	newError(s.name, " querying: ", domain).AtInfo().WriteToLog(session.ExportIDToError(ctx))
 
 	if s.name+"." == "DOH//"+domain {
@@ -243,7 +242,7 @@ func (s *DoHNameServer) sendQuery(ctx context.Context, domain string, option dns
 		return
 	}
 
-	reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(s.clientIP))
+	reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(clientIP))
 
 	var deadline time.Time
 	if d, ok := ctx.Deadline(); ok {
@@ -265,7 +264,7 @@ func (s *DoHNameServer) sendQuery(ctx context.Context, domain string, option dns
 
 			dnsCtx = session.ContextWithContent(dnsCtx, &session.Content{
 				Protocol:       "https",
-				//SkipRoutePick: true,
+				SkipDNSResolve: true,
 			})
 
 			// forced to use mux for DOH
@@ -349,7 +348,7 @@ func (s *DoHNameServer) findIPsForDomain(domain string, option dns_feature.IPOpt
 	}
 
 	if len(ips) > 0 {
-		return toNetIP(ips), nil
+		return toNetIP(ips)
 	}
 
 	if lastErr != nil {
@@ -363,16 +362,22 @@ func (s *DoHNameServer) findIPsForDomain(domain string, option dns_feature.IPOpt
 	return nil, errRecordNotFound
 }
 
-// QueryIP is called from dns.Server->queryIPTimeout
-func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, option dns_feature.IPOption) ([]net.IP, error) { // nolint: dupl
+// QueryIP implements Server.
+func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption, cs CacheStrategy) ([]net.IP, error) { // nolint: dupl
 	fqdn := Fqdn(domain)
 
+	if cs == CacheStrategy_Cache_DISABLE {
+		newError("DNS cache is disabled. Querying IP for ", domain, " at ", s.name).AtDebug().WriteToLog()
+	} else {
 		ips, err := s.findIPsForDomain(fqdn, option)
 		if err != errRecordNotFound {
+			if cs == CacheStrategy_Cache_ALL || (cs == CacheStrategy_Cache_NOERROR && err == nil) {
 				newError(s.name, " cache HIT ", domain, " -> ", ips).Base(err).AtDebug().WriteToLog()
-		log.Record(&log.DNSLog{s.name, domain, ips, log.DNSCacheHit, 0, err})
+				log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Error: err})
 				return ips, err
 			}
+		}
+	}
 
 	// ipv4 and ipv6 belong to different subscription groups
 	var sub4, sub6 *pubsub.Subscriber
@@ -400,7 +405,7 @@ func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, option dns_f
 		}
 		close(done)
 	}()
-	s.sendQuery(ctx, fqdn, option)
+	s.sendQuery(ctx, fqdn, clientIP, option)
 	start := time.Now()
 
 	for {

app/dns/nameserver_doh_test.go

@@ -0,0 +1,60 @@
+package dns_test
+
+import (
+	"context"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/google/go-cmp/cmp"
+
+	. "github.com/xtls/xray-core/app/dns"
+	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/net"
+	dns_feature "github.com/xtls/xray-core/features/dns"
+)
+
+func TestDOHNameServer(t *testing.T) {
+	url, err := url.Parse("https+local://1.1.1.1/dns-query")
+	common.Must(err)
+
+	s := NewDoHLocalNameServer(url)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+	ips, err := s.QueryIP(ctx, "google.com", net.IP(nil), dns_feature.IPOption{
+		IPv4Enable: true,
+		IPv6Enable: true,
+	}, CacheStrategy_Cache_ALL)
+	cancel()
+	common.Must(err)
+	if len(ips) == 0 {
+		t.Error("expect some ips, but got 0")
+	}
+}
+
+func TestDOHNameServerWithCache(t *testing.T) {
+	url, err := url.Parse("https+local://1.1.1.1/dns-query")
+	common.Must(err)
+
+	s := NewDoHLocalNameServer(url)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+	ips, err := s.QueryIP(ctx, "google.com", net.IP(nil), dns_feature.IPOption{
+		IPv4Enable: true,
+		IPv6Enable: true,
+	}, CacheStrategy_Cache_ALL)
+	cancel()
+	common.Must(err)
+	if len(ips) == 0 {
+		t.Error("expect some ips, but got 0")
+	}
+
+	ctx2, cancel := context.WithTimeout(context.Background(), time.Second*2)
+	ips2, err := s.QueryIP(ctx2, "google.com", net.IP(nil), dns_feature.IPOption{
+		IPv4Enable: true,
+		IPv6Enable: true,
+	}, CacheStrategy_Cache_ALL)
+	cancel()
+	common.Must(err)
+	if r := cmp.Diff(ips2, ips); r != "" {
+		t.Fatal(r)
+	}
+}

app/dns/nameserver_fakedns.go

@@ -16,11 +16,13 @@ func NewFakeDNSServer() *FakeDNSServer {
 	return &FakeDNSServer{}
 }
 
+const FakeDNSName = "FakeDNS"
+
 func (FakeDNSServer) Name() string {
-	return "FakeDNS"
+	return FakeDNSName
 }
 
-func (f *FakeDNSServer) QueryIP(ctx context.Context, domain string, _ dns.IPOption) ([]net.IP, error) {
+func (f *FakeDNSServer) QueryIP(ctx context.Context, domain string, _ net.IP, _ dns.IPOption, _ CacheStrategy) ([]net.IP, error) {
 	if f.fakeDNSEngine == nil {
 		if err := core.RequireFeatures(ctx, func(fd dns.FakeDNSEngine) {
 			f.fakeDNSEngine = fd
@@ -30,9 +32,9 @@ func (f *FakeDNSServer) QueryIP(ctx context.Context, domain string, _ dns.IPOpti
 	}
 	ips := f.fakeDNSEngine.GetFakeIPForDomain(domain)
 
-	netIP := toNetIP(ips)
-	if netIP == nil {
-		return nil, newError("Unable to convert IP to net ip").AtError()
+	netIP, err := toNetIP(ips)
+	if err != nil {
+		return nil, newError("Unable to convert IP to net ip").Base(err).AtError()
 	}
 
 	newError(f.Name(), " got answer: ", domain, " -> ", ips).AtInfo().WriteToLog()

app/dns/nameserver_local.go

@@ -0,0 +1,53 @@
+package dns
+
+import (
+	"context"
+
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/features/dns"
+	"github.com/xtls/xray-core/features/dns/localdns"
+)
+
+// LocalNameServer is an wrapper over local DNS feature.
+type LocalNameServer struct {
+	client *localdns.Client
+}
+
+// QueryIP implements Server.
+func (s *LocalNameServer) QueryIP(_ context.Context, domain string, _ net.IP, option dns.IPOption, _ CacheStrategy) ([]net.IP, error) {
+	var ips []net.IP
+	var err error
+
+	switch {
+	case option.IPv4Enable && option.IPv6Enable:
+		ips, err = s.client.LookupIP(domain)
+	case option.IPv4Enable:
+		ips, err = s.client.LookupIPv4(domain)
+	case option.IPv6Enable:
+		ips, err = s.client.LookupIPv6(domain)
+	}
+
+	if len(ips) > 0 {
+		newError("Localhost got answer: ", domain, " -> ", ips).AtInfo().WriteToLog()
+	}
+
+	return ips, err
+}
+
+// Name implements Server.
+func (s *LocalNameServer) Name() string {
+	return "localhost"
+}
+
+// NewLocalNameServer creates localdns server object for directly lookup in system DNS.
+func NewLocalNameServer() *LocalNameServer {
+	newError("DNS: created localhost client").AtInfo().WriteToLog()
+	return &LocalNameServer{
+		client: localdns.New(),
+	}
+}
+
+// NewLocalDNSClient creates localdns client object for directly lookup in system DNS.
+func NewLocalDNSClient() *Client {
+	return &Client{server: NewLocalNameServer()}
+}

app/dns/nameserver_local_test.go

@@ -7,17 +7,17 @@ import (
 
 	. "github.com/xtls/xray-core/app/dns"
 	"github.com/xtls/xray-core/common"
-	dns_feature "github.com/xtls/xray-core/features/dns"
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/features/dns"
 )
 
 func TestLocalNameServer(t *testing.T) {
 	s := NewLocalNameServer()
-	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
-	ips, err := s.QueryIP(ctx, "google.com", dns_feature.IPOption{
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+	ips, err := s.QueryIP(ctx, "google.com", net.IP{}, dns.IPOption{
 		IPv4Enable: true,
 		IPv6Enable: true,
-		FakeEnable: false,
-	})
+	}, CacheStrategy_Cache_ALL)
 	cancel()
 	common.Must(err)
 	if len(ips) == 0 {

app/dns/nameserver_quic.go

@@ -0,0 +1,394 @@
+package dns
+
+import (
+	"context"
+	"net/url"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/lucas-clemente/quic-go"
+	"golang.org/x/net/dns/dnsmessage"
+	"golang.org/x/net/http2"
+
+	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/buf"
+	"github.com/xtls/xray-core/common/log"
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/common/protocol/dns"
+	"github.com/xtls/xray-core/common/session"
+	"github.com/xtls/xray-core/common/signal/pubsub"
+	"github.com/xtls/xray-core/common/task"
+	dns_feature "github.com/xtls/xray-core/features/dns"
+	"github.com/xtls/xray-core/transport/internet/tls"
+)
+
+// NextProtoDQ - During connection establishment, DNS/QUIC support is indicated
+// by selecting the ALPN token "dq" in the crypto handshake.
+const NextProtoDQ = "doq-i00"
+
+// QUICNameServer implemented DNS over QUIC
+type QUICNameServer struct {
+	sync.RWMutex
+	ips         map[string]record
+	pub         *pubsub.Service
+	cleanup     *task.Periodic
+	reqID       uint32
+	name        string
+	destination net.Destination
+	session     quic.Session
+}
+
+// NewQUICNameServer creates DNS-over-QUIC client object for local resolving
+func NewQUICNameServer(url *url.URL) (*QUICNameServer, error) {
+	newError("DNS: created Local DNS-over-QUIC client for ", url.String()).AtInfo().WriteToLog()
+
+	var err error
+	port := net.Port(784)
+	if url.Port() != "" {
+		port, err = net.PortFromString(url.Port())
+		if err != nil {
+			return nil, err
+		}
+	}
+	dest := net.UDPDestination(net.DomainAddress(url.Hostname()), port)
+
+	s := &QUICNameServer{
+		ips:         make(map[string]record),
+		pub:         pubsub.NewService(),
+		name:        url.String(),
+		destination: dest,
+	}
+	s.cleanup = &task.Periodic{
+		Interval: time.Minute,
+		Execute:  s.Cleanup,
+	}
+
+	return s, nil
+}
+
+// Name returns client name
+func (s *QUICNameServer) Name() string {
+	return s.name
+}
+
+// Cleanup clears expired items from cache
+func (s *QUICNameServer) Cleanup() error {
+	now := time.Now()
+	s.Lock()
+	defer s.Unlock()
+
+	if len(s.ips) == 0 {
+		return newError("nothing to do. stopping...")
+	}
+
+	for domain, record := range s.ips {
+		if record.A != nil && record.A.Expire.Before(now) {
+			record.A = nil
+		}
+		if record.AAAA != nil && record.AAAA.Expire.Before(now) {
+			record.AAAA = nil
+		}
+
+		if record.A == nil && record.AAAA == nil {
+			newError(s.name, " cleanup ", domain).AtDebug().WriteToLog()
+			delete(s.ips, domain)
+		} else {
+			s.ips[domain] = record
+		}
+	}
+
+	if len(s.ips) == 0 {
+		s.ips = make(map[string]record)
+	}
+
+	return nil
+}
+
+func (s *QUICNameServer) updateIP(req *dnsRequest, ipRec *IPRecord) {
+	elapsed := time.Since(req.start)
+
+	s.Lock()
+	rec := s.ips[req.domain]
+	updated := false
+
+	switch req.reqType {
+	case dnsmessage.TypeA:
+		if isNewer(rec.A, ipRec) {
+			rec.A = ipRec
+			updated = true
+		}
+	case dnsmessage.TypeAAAA:
+		addr := make([]net.Address, 0)
+		for _, ip := range ipRec.IP {
+			if len(ip.IP()) == net.IPv6len {
+				addr = append(addr, ip)
+			}
+		}
+		ipRec.IP = addr
+		if isNewer(rec.AAAA, ipRec) {
+			rec.AAAA = ipRec
+			updated = true
+		}
+	}
+	newError(s.name, " got answer: ", req.domain, " ", req.reqType, " -> ", ipRec.IP, " ", elapsed).AtInfo().WriteToLog()
+
+	if updated {
+		s.ips[req.domain] = rec
+	}
+	switch req.reqType {
+	case dnsmessage.TypeA:
+		s.pub.Publish(req.domain+"4", nil)
+	case dnsmessage.TypeAAAA:
+		s.pub.Publish(req.domain+"6", nil)
+	}
+	s.Unlock()
+	common.Must(s.cleanup.Start())
+}
+
+func (s *QUICNameServer) newReqID() uint16 {
+	return uint16(atomic.AddUint32(&s.reqID, 1))
+}
+
+func (s *QUICNameServer) sendQuery(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption) {
+	newError(s.name, " querying: ", domain).AtInfo().WriteToLog(session.ExportIDToError(ctx))
+
+	reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(clientIP))
+
+	var deadline time.Time
+	if d, ok := ctx.Deadline(); ok {
+		deadline = d
+	} else {
+		deadline = time.Now().Add(time.Second * 5)
+	}
+
+	for _, req := range reqs {
+		go func(r *dnsRequest) {
+			// generate new context for each req, using same context
+			// may cause reqs all aborted if any one encounter an error
+			dnsCtx := context.Background()
+
+			// reserve internal dns server requested Inbound
+			if inbound := session.InboundFromContext(ctx); inbound != nil {
+				dnsCtx = session.ContextWithInbound(dnsCtx, inbound)
+			}
+			dnsCtx = session.ContextWithContent(dnsCtx, &session.Content{
+				Protocol:       "quic",
+				SkipDNSResolve: true,
+			})
+			dnsCtx = log.ContextWithAccessMessage(dnsCtx, &log.AccessMessage{
+				From:   "DoQ",
+				To:     s.name,
+				Status: log.AccessAccepted,
+				Reason: "",
+			})
+
+			var cancel context.CancelFunc
+			dnsCtx, cancel = context.WithDeadline(dnsCtx, deadline)
+			defer cancel()
+
+			b, err := dns.PackMessage(r.msg)
+			if err != nil {
+				newError("failed to pack dns query").Base(err).AtError().WriteToLog()
+				return
+			}
+
+			conn, err := s.openStream(dnsCtx)
+			if err != nil {
+				newError("failed to open quic session").Base(err).AtError().WriteToLog()
+				return
+			}
+
+			_, err = conn.Write(b.Bytes())
+			if err != nil {
+				newError("failed to send query").Base(err).AtError().WriteToLog()
+				return
+			}
+
+			_ = conn.Close()
+
+			respBuf := buf.New()
+			defer respBuf.Release()
+			n, err := respBuf.ReadFrom(conn)
+			if err != nil && n == 0 {
+				newError("failed to read response").Base(err).AtError().WriteToLog()
+				return
+			}
+
+			rec, err := parseResponse(respBuf.Bytes())
+			if err != nil {
+				newError("failed to handle response").Base(err).AtError().WriteToLog()
+				return
+			}
+			s.updateIP(r, rec)
+		}(req)
+	}
+}
+
+func (s *QUICNameServer) findIPsForDomain(domain string, option dns_feature.IPOption) ([]net.IP, error) {
+	s.RLock()
+	record, found := s.ips[domain]
+	s.RUnlock()
+
+	if !found {
+		return nil, errRecordNotFound
+	}
+
+	var ips []net.Address
+	var lastErr error
+	if option.IPv6Enable && record.AAAA != nil && record.AAAA.RCode == dnsmessage.RCodeSuccess {
+		aaaa, err := record.AAAA.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, aaaa...)
+	}
+
+	if option.IPv4Enable && record.A != nil && record.A.RCode == dnsmessage.RCodeSuccess {
+		a, err := record.A.getIPs()
+		if err != nil {
+			lastErr = err
+		}
+		ips = append(ips, a...)
+	}
+
+	if len(ips) > 0 {
+		return toNetIP(ips)
+	}
+
+	if lastErr != nil {
+		return nil, lastErr
+	}
+
+	if (option.IPv4Enable && record.A != nil) || (option.IPv6Enable && record.AAAA != nil) {
+		return nil, dns_feature.ErrEmptyResponse
+	}
+
+	return nil, errRecordNotFound
+}
+
+// QueryIP is called from dns.Server->queryIPTimeout
+func (s *QUICNameServer) QueryIP(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption, cs CacheStrategy) ([]net.IP, error) {
+	fqdn := Fqdn(domain)
+
+	if cs == CacheStrategy_Cache_DISABLE {
+		newError("DNS cache is disabled. Querying IP for ", domain, " at ", s.name).AtDebug().WriteToLog()
+	} else {
+		ips, err := s.findIPsForDomain(fqdn, option)
+		if err != errRecordNotFound {
+			if cs == CacheStrategy_Cache_ALL || (cs == CacheStrategy_Cache_NOERROR && err == nil) {
+				newError(s.name, " cache HIT ", domain, " -> ", ips).Base(err).AtDebug().WriteToLog()
+				log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Error: err})
+				return ips, err
+			}
+		}
+	}
+
+	// ipv4 and ipv6 belong to different subscription groups
+	var sub4, sub6 *pubsub.Subscriber
+	if option.IPv4Enable {
+		sub4 = s.pub.Subscribe(fqdn + "4")
+		defer sub4.Close()
+	}
+	if option.IPv6Enable {
+		sub6 = s.pub.Subscribe(fqdn + "6")
+		defer sub6.Close()
+	}
+	done := make(chan interface{})
+	go func() {
+		if sub4 != nil {
+			select {
+			case <-sub4.Wait():
+			case <-ctx.Done():
+			}
+		}
+		if sub6 != nil {
+			select {
+			case <-sub6.Wait():
+			case <-ctx.Done():
+			}
+		}
+		close(done)
+	}()
+	s.sendQuery(ctx, fqdn, clientIP, option)
+	start := time.Now()
+
+	for {
+		ips, err := s.findIPsForDomain(fqdn, option)
+		if err != errRecordNotFound {
+			log.Record(&log.DNSLog{s.name, domain, ips, log.DNSQueried, time.Since(start), err})
+			return ips, err
+		}
+
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case <-done:
+		}
+	}
+}
+
+func isActive(s quic.Session) bool {
+	select {
+	case <-s.Context().Done():
+		return false
+	default:
+		return true
+	}
+}
+
+func (s *QUICNameServer) getSession() (quic.Session, error) {
+	var session quic.Session
+	s.RLock()
+	session = s.session
+	if session != nil && isActive(session) {
+		s.RUnlock()
+		return session, nil
+	}
+	if session != nil {
+		// we're recreating the session, let's create a new one
+		_ = session.CloseWithError(0, "")
+	}
+	s.RUnlock()
+
+	s.Lock()
+	defer s.Unlock()
+
+	var err error
+	session, err = s.openSession()
+	if err != nil {
+		// This does not look too nice, but QUIC (or maybe quic-go)
+		// doesn't seem stable enough.
+		// Maybe retransmissions aren't fully implemented in quic-go?
+		// Anyways, the simple solution is to make a second try when
+		// it fails to open the QUIC session.
+		session, err = s.openSession()
+		if err != nil {
+			return nil, err
+		}
+	}
+	s.session = session
+	return session, nil
+}
+
+func (s *QUICNameServer) openSession() (quic.Session, error) {
+	tlsConfig := tls.Config{}
+	quicConfig := &quic.Config{}
+
+	session, err := quic.DialAddrContext(context.Background(), s.destination.NetAddr(), tlsConfig.GetTLSConfig(tls.WithNextProto("http/1.1", http2.NextProtoTLS, NextProtoDQ)), quicConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	return session, nil
+}
+
+func (s *QUICNameServer) openStream(ctx context.Context) (quic.Stream, error) {
+	session, err := s.getSession()
+	if err != nil {
+		return nil, err
+	}
+
+	// open a new stream
+	return session.OpenStreamSync(ctx)
+}

app/dns/nameserver_quic_test.go

@@ -0,0 +1,60 @@
+package dns_test
+
+import (
+	"context"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/google/go-cmp/cmp"
+
+	. "github.com/xtls/xray-core/app/dns"
+	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/net"
+	dns_feature "github.com/xtls/xray-core/features/dns"
+)
+
+func TestQUICNameServer(t *testing.T) {
+	url, err := url.Parse("quic://dns.adguard.com")
+	common.Must(err)
+	s, err := NewQUICNameServer(url)
+	common.Must(err)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+	ips, err := s.QueryIP(ctx, "google.com", net.IP(nil), dns_feature.IPOption{
+		IPv4Enable: true,
+		IPv6Enable: true,
+	}, CacheStrategy_Cache_ALL)
+	cancel()
+	common.Must(err)
+	if len(ips) == 0 {
+		t.Error("expect some ips, but got 0")
+	}
+}
+
+func TestQUICNameServerWithCache(t *testing.T) {
+	url, err := url.Parse("quic://dns.adguard.com")
+	common.Must(err)
+	s, err := NewQUICNameServer(url)
+	common.Must(err)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
+	ips, err := s.QueryIP(ctx, "google.com", net.IP(nil), dns_feature.IPOption{
+		IPv4Enable: true,
+		IPv6Enable: true,
+	}, CacheStrategy_Cache_ALL)
+	cancel()
+	common.Must(err)
+	if len(ips) == 0 {
+		t.Error("expect some ips, but got 0")
+	}
+
+	ctx2, cancel := context.WithTimeout(context.Background(), time.Second*5)
+	ips2, err := s.QueryIP(ctx2, "google.com", net.IP(nil), dns_feature.IPOption{
+		IPv4Enable: true,
+		IPv6Enable: true,
+	}, CacheStrategy_Cache_ALL)
+	cancel()
+	common.Must(err)
+	if r := cmp.Diff(ips2, ips); r != "" {
+		t.Fatal(r)
+	}
+}

app/dns/nameserver_udp.go

@@ -2,7 +2,6 @@ package dns
 
 import (
 	"context"
-	"github.com/xtls/xray-core/transport/internet"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -32,10 +31,10 @@ type ClassicNameServer struct {
 	udpServer *udp.Dispatcher
 	cleanup   *task.Periodic
 	reqID     uint32
-	clientIP  net.IP
 }
 
-func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher, clientIP net.IP) *ClassicNameServer {
+// NewClassicNameServer creates udp server object for remote resolving.
+func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher) *ClassicNameServer {
 	// default to 53 if unspecific
 	if address.Port == 0 {
 		address.Port = net.Port(53)
@@ -45,7 +44,6 @@ func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher
 		address:  address,
 		ips:      make(map[string]record),
 		requests: make(map[uint16]dnsRequest),
-		clientIP: clientIP,
 		pub:      pubsub.NewService(),
 		name:     strings.ToUpper(address.String()),
 	}
@@ -58,10 +56,12 @@ func NewClassicNameServer(address net.Destination, dispatcher routing.Dispatcher
 	return s
 }
 
+// Name implements Server.
 func (s *ClassicNameServer) Name() string {
 	return s.name
 }
 
+// Cleanup clears expired items from cache
 func (s *ClassicNameServer) Cleanup() error {
 	now := time.Now()
 	s.Lock()
@@ -103,6 +103,7 @@ func (s *ClassicNameServer) Cleanup() error {
 	return nil
 }
 
+// HandleResponse handles udp response packet from remote DNS server.
 func (s *ClassicNameServer) HandleResponse(ctx context.Context, packet *udp_proto.Packet) {
 	ipRec, err := parseResponse(packet.Payload.Bytes())
 	if err != nil {
@@ -180,10 +181,10 @@ func (s *ClassicNameServer) addPendingRequest(req *dnsRequest) {
 	s.requests[id] = *req
 }
 
-func (s *ClassicNameServer) sendQuery(ctx context.Context, domain string, option dns_feature.IPOption) {
+func (s *ClassicNameServer) sendQuery(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption) {
 	newError(s.name, " querying DNS for: ", domain).AtDebug().WriteToLog(session.ExportIDToError(ctx))
 
-	reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(s.clientIP))
+	reqs := buildReqMsgs(domain, option, s.newReqID, genEDNS0Options(clientIP))
 
 	for _, req := range reqs {
 		s.addPendingRequest(req)
@@ -192,7 +193,6 @@ func (s *ClassicNameServer) sendQuery(ctx context.Context, domain string, option
 		if inbound := session.InboundFromContext(ctx); inbound != nil {
 			udpCtx = session.ContextWithInbound(udpCtx, inbound)
 		}
-		udpCtx = internet.ContextWithLookupDomain(udpCtx, internet.LookupDomainFromContext(ctx))
 		udpCtx = session.ContextWithContent(udpCtx, &session.Content{
 			Protocol: "dns",
 		})
@@ -234,7 +234,7 @@ func (s *ClassicNameServer) findIPsForDomain(domain string, option dns_feature.I
 	}
 
 	if len(ips) > 0 {
-		return toNetIP(ips), nil
+		return toNetIP(ips)
 	}
 
 	if lastErr != nil {
@@ -245,15 +245,21 @@ func (s *ClassicNameServer) findIPsForDomain(domain string, option dns_feature.I
 }
 
 // QueryIP implements Server.
-func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, option dns_feature.IPOption) ([]net.IP, error) {
+func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption, cs CacheStrategy) ([]net.IP, error) {
 	fqdn := Fqdn(domain)
 
+	if cs == CacheStrategy_Cache_DISABLE {
+		newError("DNS cache is disabled. Querying IP for ", domain, " at ", s.name).AtDebug().WriteToLog()
+	} else {
 		ips, err := s.findIPsForDomain(fqdn, option)
 		if err != errRecordNotFound {
+			if cs == CacheStrategy_Cache_ALL || (cs == CacheStrategy_Cache_NOERROR && err == nil) {
 				newError(s.name, " cache HIT ", domain, " -> ", ips).Base(err).AtDebug().WriteToLog()
-		log.Record(&log.DNSLog{s.name, domain, ips, log.DNSCacheHit, 0, err})
+				log.Record(&log.DNSLog{Server: s.name, Domain: domain, Result: ips, Status: log.DNSCacheHit, Error: err})
 				return ips, err
 			}
+		}
+	}
 
 	// ipv4 and ipv6 belong to different subscription groups
 	var sub4, sub6 *pubsub.Subscriber
@@ -281,7 +287,7 @@ func (s *ClassicNameServer) QueryIP(ctx context.Context, domain string, option d
 		}
 		close(done)
 	}()
-	s.sendQuery(ctx, fqdn, option)
+	s.sendQuery(ctx, fqdn, clientIP, option)
 	start := time.Now()
 
 	for {

app/dns/options.go

@@ -0,0 +1,16 @@
+package dns
+
+import "github.com/xtls/xray-core/features/dns"
+
+func isIPQuery(o *dns.IPOption) bool {
+	return o.IPv4Enable || o.IPv6Enable
+}
+
+func canQueryOnClient(o *dns.IPOption, c *Client) bool {
+	isIPClient := !(c.Name() == FakeDNSName)
+	return isIPClient && isIPQuery(o)
+}
+
+func isQuery(o *dns.IPOption) bool {
+	return !(o.IPv4Enable || o.IPv6Enable || o.FakeEnable)
+}

app/dns/server.go

@@ -1,438 +0,0 @@
-package dns
-
-//go:generate go run github.com/xtls/xray-core/common/errors/errorgen
-
-import (
-	"context"
-	"fmt"
-	"log"
-	"net/url"
-	"strings"
-	"sync"
-	"time"
-
-	"github.com/xtls/xray-core/app/router"
-	"github.com/xtls/xray-core/common"
-	"github.com/xtls/xray-core/common/errors"
-	"github.com/xtls/xray-core/common/net"
-	"github.com/xtls/xray-core/common/session"
-	"github.com/xtls/xray-core/common/strmatcher"
-	"github.com/xtls/xray-core/common/uuid"
-	core "github.com/xtls/xray-core/core"
-	"github.com/xtls/xray-core/features"
-	"github.com/xtls/xray-core/features/dns"
-	"github.com/xtls/xray-core/features/routing"
-	"github.com/xtls/xray-core/transport/internet"
-)
-
-// Server is a DNS rely server.
-type Server struct {
-	sync.Mutex
-	hosts         *StaticHosts
-	clientIP      net.IP
-	clients       []Client // clientIdx -> Client
-	ctx           context.Context
-	ipIndexMap    []*MultiGeoIPMatcher // clientIdx -> *MultiGeoIPMatcher
-	domainRules   [][]string           // clientIdx -> domainRuleIdx -> DomainRule
-	domainMatcher strmatcher.IndexMatcher
-	matcherInfos  []DomainMatcherInfo // matcherIdx -> DomainMatcherInfo
-	tag           string
-}
-
-// DomainMatcherInfo contains information attached to index returned by Server.domainMatcher
-type DomainMatcherInfo struct {
-	clientIdx     uint16
-	domainRuleIdx uint16
-}
-
-// MultiGeoIPMatcher for match
-type MultiGeoIPMatcher struct {
-	matchers []*router.GeoIPMatcher
-}
-
-var errExpectedIPNonMatch = errors.New("expectIPs not match")
-
-// Match check ip match
-func (c *MultiGeoIPMatcher) Match(ip net.IP) bool {
-	for _, matcher := range c.matchers {
-		if matcher.Match(ip) {
-			return true
-		}
-	}
-	return false
-}
-
-// HasMatcher check has matcher
-func (c *MultiGeoIPMatcher) HasMatcher() bool {
-	return len(c.matchers) > 0
-}
-
-func generateRandomTag() string {
-	id := uuid.New()
-	return "xray.system." + id.String()
-}
-
-// New creates a new DNS server with given configuration.
-func New(ctx context.Context, config *Config) (*Server, error) {
-	server := &Server{
-		clients: make([]Client, 0, len(config.NameServers)+len(config.NameServer)),
-		ctx:     ctx,
-		tag:     config.Tag,
-	}
-	if server.tag == "" {
-		server.tag = generateRandomTag()
-	}
-	if len(config.ClientIp) > 0 {
-		if len(config.ClientIp) != net.IPv4len && len(config.ClientIp) != net.IPv6len {
-			return nil, newError("unexpected IP length", len(config.ClientIp))
-		}
-		server.clientIP = net.IP(config.ClientIp)
-	}
-
-	hosts, err := NewStaticHosts(config.StaticHosts, config.Hosts)
-	if err != nil {
-		return nil, newError("failed to create hosts").Base(err)
-	}
-	server.hosts = hosts
-
-	addNameServer := func(ns *NameServer) int {
-		endpoint := ns.Address
-		address := endpoint.Address.AsAddress()
-
-		switch {
-		case address.Family().IsDomain() && address.Domain() == "localhost":
-			server.clients = append(server.clients, NewLocalNameServer())
-			// Priotize local domains with specific TLDs or without any dot to local DNS
-			// References:
-			// https://www.iana.org/assignments/special-use-domain-names/special-use-domain-names.xhtml
-			// https://unix.stackexchange.com/questions/92441/whats-the-difference-between-local-home-and-lan
-			localTLDsAndDotlessDomains := []*NameServer_PriorityDomain{
-				{Type: DomainMatchingType_Regex, Domain: "^[^.]+$"}, // This will only match domains without any dot
-				{Type: DomainMatchingType_Subdomain, Domain: "local"},
-				{Type: DomainMatchingType_Subdomain, Domain: "localdomain"},
-				{Type: DomainMatchingType_Subdomain, Domain: "localhost"},
-				{Type: DomainMatchingType_Subdomain, Domain: "lan"},
-				{Type: DomainMatchingType_Subdomain, Domain: "home.arpa"},
-				{Type: DomainMatchingType_Subdomain, Domain: "example"},
-				{Type: DomainMatchingType_Subdomain, Domain: "invalid"},
-				{Type: DomainMatchingType_Subdomain, Domain: "test"},
-			}
-			ns.PrioritizedDomain = append(ns.PrioritizedDomain, localTLDsAndDotlessDomains...)
-
-		case address.Family().IsDomain() && strings.HasPrefix(address.Domain(), "https+local://"):
-			// URI schemed string treated as domain
-			// DOH Local mode
-			u, err := url.Parse(address.Domain())
-			if err != nil {
-				log.Fatalln(newError("DNS config error").Base(err))
-			}
-			server.clients = append(server.clients, NewDoHLocalNameServer(u, server.clientIP))
-
-		case address.Family().IsDomain() && strings.HasPrefix(address.Domain(), "https://"):
-			// DOH Remote mode
-			u, err := url.Parse(address.Domain())
-			if err != nil {
-				log.Fatalln(newError("DNS config error").Base(err))
-			}
-			idx := len(server.clients)
-			server.clients = append(server.clients, nil)
-
-			// need the core dispatcher, register DOHClient at callback
-			common.Must(core.RequireFeatures(ctx, func(d routing.Dispatcher) {
-				c, err := NewDoHNameServer(u, d, server.clientIP)
-				if err != nil {
-					log.Fatalln(newError("DNS config error").Base(err))
-				}
-				server.clients[idx] = c
-			}))
-
-		case address.Family().IsDomain() && address.Domain() == "fakedns":
-			server.clients = append(server.clients, NewFakeDNSServer())
-
-		default:
-			// UDP classic DNS mode
-			dest := endpoint.AsDestination()
-			if dest.Network == net.Network_Unknown {
-				dest.Network = net.Network_UDP
-			}
-			if dest.Network == net.Network_UDP {
-				idx := len(server.clients)
-				server.clients = append(server.clients, nil)
-
-				common.Must(core.RequireFeatures(ctx, func(d routing.Dispatcher) {
-					server.clients[idx] = NewClassicNameServer(dest, d, server.clientIP)
-				}))
-			}
-		}
-		server.ipIndexMap = append(server.ipIndexMap, nil)
-		return len(server.clients) - 1
-	}
-
-	if len(config.NameServers) > 0 {
-		features.PrintDeprecatedFeatureWarning("simple DNS server")
-		for _, destPB := range config.NameServers {
-			addNameServer(&NameServer{Address: destPB})
-		}
-	}
-
-	if len(config.NameServer) > 0 {
-		clientIndices := []int{}
-		domainRuleCount := 0
-		for _, ns := range config.NameServer {
-			idx := addNameServer(ns)
-			clientIndices = append(clientIndices, idx)
-			domainRuleCount += len(ns.PrioritizedDomain)
-		}
-
-		domainRules := make([][]string, len(server.clients))
-		domainMatcher := &strmatcher.MatcherGroup{}
-		matcherInfos := make([]DomainMatcherInfo, domainRuleCount+1) // matcher index starts from 1
-		var geoIPMatcherContainer router.GeoIPMatcherContainer
-		for nidx, ns := range config.NameServer {
-			idx := clientIndices[nidx]
-
-			// Establish domain rule matcher
-			rules := []string{}
-			ruleCurr := 0
-			ruleIter := 0
-			for _, domain := range ns.PrioritizedDomain {
-				matcher, err := toStrMatcher(domain.Type, domain.Domain)
-				if err != nil {
-					return nil, newError("failed to create prioritized domain").Base(err).AtWarning()
-				}
-				midx := domainMatcher.Add(matcher)
-				if midx >= uint32(len(matcherInfos)) { // This rarely happens according to current matcher's implementation
-					newError("expanding domain matcher info array to size ", midx, " when adding ", matcher).AtDebug().WriteToLog()
-					matcherInfos = append(matcherInfos, make([]DomainMatcherInfo, midx-uint32(len(matcherInfos))+1)...)
-				}
-				info := &matcherInfos[midx]
-				info.clientIdx = uint16(idx)
-				if ruleCurr < len(ns.OriginalRules) {
-					info.domainRuleIdx = uint16(ruleCurr)
-					rule := ns.OriginalRules[ruleCurr]
-					if ruleCurr >= len(rules) {
-						rules = append(rules, rule.Rule)
-					}
-					ruleIter++
-					if ruleIter >= int(rule.Size) {
-						ruleIter = 0
-						ruleCurr++
-					}
-				} else { // No original rule, generate one according to current domain matcher (majorly for compatibility with tests)
-					info.domainRuleIdx = uint16(len(rules))
-					rules = append(rules, matcher.String())
-				}
-			}
-			domainRules[idx] = rules
-
-			// only add to ipIndexMap if GeoIP is configured
-			if len(ns.Geoip) > 0 {
-				var matchers []*router.GeoIPMatcher
-				for _, geoip := range ns.Geoip {
-					matcher, err := geoIPMatcherContainer.Add(geoip)
-					if err != nil {
-						return nil, newError("failed to create ip matcher").Base(err).AtWarning()
-					}
-					matchers = append(matchers, matcher)
-				}
-				matcher := &MultiGeoIPMatcher{matchers: matchers}
-				server.ipIndexMap[idx] = matcher
-			}
-		}
-		server.domainRules = domainRules
-		server.domainMatcher = domainMatcher
-		server.matcherInfos = matcherInfos
-	}
-
-	if len(server.clients) == 0 {
-		server.clients = append(server.clients, NewLocalNameServer())
-		server.ipIndexMap = append(server.ipIndexMap, nil)
-	}
-
-	return server, nil
-}
-
-// Type implements common.HasType.
-func (*Server) Type() interface{} {
-	return dns.ClientType()
-}
-
-// Start implements common.Runnable.
-func (s *Server) Start() error {
-	return nil
-}
-
-// Close implements common.Closable.
-func (s *Server) Close() error {
-	return nil
-}
-
-func (s *Server) IsOwnLink(ctx context.Context) bool {
-	inbound := session.InboundFromContext(ctx)
-	return inbound != nil && inbound.Tag == s.tag
-}
-
-// Match check dns ip match geoip
-func (s *Server) Match(idx int, client Client, domain string, ips []net.IP) ([]net.IP, error) {
-	var matcher *MultiGeoIPMatcher
-	if idx < len(s.ipIndexMap) {
-		matcher = s.ipIndexMap[idx]
-	}
-	if matcher == nil {
-		return ips, nil
-	}
-
-	if !matcher.HasMatcher() {
-		newError("domain ", domain, " server has no valid matcher: ", client.Name(), " idx:", idx).AtDebug().WriteToLog()
-		return ips, nil
-	}
-
-	newIps := []net.IP{}
-	for _, ip := range ips {
-		if matcher.Match(ip) {
-			newIps = append(newIps, ip)
-		}
-	}
-	if len(newIps) == 0 {
-		return nil, errExpectedIPNonMatch
-	}
-	newError("domain ", domain, " expectIPs ", newIps, " matched at server ", client.Name(), " idx:", idx).AtDebug().WriteToLog()
-	return newIps, nil
-}
-
-func (s *Server) queryIPTimeout(idx int, client Client, domain string, option dns.IPOption) ([]net.IP, error) {
-	ctx, cancel := context.WithTimeout(s.ctx, time.Second*4)
-	if len(s.tag) > 0 {
-		ctx = session.ContextWithInbound(ctx, &session.Inbound{
-			Tag: s.tag,
-		})
-	}
-	ctx = internet.ContextWithLookupDomain(ctx, domain)
-	ips, err := client.QueryIP(ctx, domain, option)
-	cancel()
-
-	if err != nil {
-		return ips, err
-	}
-
-	ips, err = s.Match(idx, client, domain, ips)
-	return ips, err
-}
-
-func (s *Server) lookupStatic(domain string, option dns.IPOption, depth int32) []net.Address {
-	ips := s.hosts.LookupIP(domain, option)
-	if ips == nil {
-		return nil
-	}
-	if ips[0].Family().IsDomain() && depth < 5 {
-		if newIPs := s.lookupStatic(ips[0].Domain(), option, depth+1); newIPs != nil {
-			return newIPs
-		}
-	}
-	return ips
-}
-
-func toNetIP(ips []net.Address) []net.IP {
-	if len(ips) == 0 {
-		return nil
-	}
-	netips := make([]net.IP, 0, len(ips))
-	for _, ip := range ips {
-		netips = append(netips, ip.IP())
-	}
-	return netips
-}
-
-// LookupIP implements dns.Client.
-func (s *Server) LookupIP(domain string, option dns.IPOption) ([]net.IP, error) {
-	if domain == "" {
-		return nil, newError("empty domain name")
-	}
-
-	// normalize the FQDN form query
-	if strings.HasSuffix(domain, ".") {
-		domain = domain[:len(domain)-1]
-	}
-
-	ips := s.lookupStatic(domain, option, 0)
-	if ips != nil && ips[0].Family().IsIP() {
-		newError("returning ", len(ips), " IPs for domain ", domain).WriteToLog()
-		return toNetIP(ips), nil
-	}
-
-	if ips != nil && ips[0].Family().IsDomain() {
-		newdomain := ips[0].Domain()
-		newError("domain replaced: ", domain, " -> ", newdomain).WriteToLog()
-		domain = newdomain
-	}
-
-	var lastErr error
-	var matchedClient Client
-	if s.domainMatcher != nil {
-		indices := s.domainMatcher.Match(domain)
-		domainRules := []string{}
-		matchingDNS := []string{}
-		for _, idx := range indices {
-			info := s.matcherInfos[idx]
-			rule := s.domainRules[info.clientIdx][info.domainRuleIdx]
-			domainRules = append(domainRules, fmt.Sprintf("%s(DNS idx:%d)", rule, info.clientIdx))
-			matchingDNS = append(matchingDNS, s.clients[info.clientIdx].Name())
-		}
-		if len(domainRules) > 0 {
-			newError("domain ", domain, " matches following rules: ", domainRules).AtDebug().WriteToLog()
-		}
-		if len(matchingDNS) > 0 {
-			newError("domain ", domain, " uses following DNS first: ", matchingDNS).AtDebug().WriteToLog()
-		}
-		for _, idx := range indices {
-			clientIdx := int(s.matcherInfos[idx].clientIdx)
-			matchedClient = s.clients[clientIdx]
-			if !option.FakeEnable && strings.EqualFold(matchedClient.Name(), "FakeDNS") {
-				newError("skip DNS resolution for domain ", domain, " at server ", matchedClient.Name()).AtDebug().WriteToLog()
-				continue
-			}
-			ips, err := s.queryIPTimeout(clientIdx, matchedClient, domain, option)
-			if len(ips) > 0 {
-				return ips, nil
-			}
-			if err == dns.ErrEmptyResponse {
-				return nil, err
-			}
-			if err != nil {
-				newError("failed to lookup ip for domain ", domain, " at server ", matchedClient.Name()).Base(err).WriteToLog()
-				lastErr = err
-			}
-		}
-	}
-
-	for idx, client := range s.clients {
-		if client == matchedClient {
-			newError("domain ", domain, " at server ", client.Name(), " idx:", idx, " already lookup failed, just ignore").AtDebug().WriteToLog()
-			continue
-		}
-		if !option.FakeEnable && strings.EqualFold(client.Name(), "FakeDNS") {
-			newError("skip DNS resolution for domain ", domain, " at server ", client.Name()).AtDebug().WriteToLog()
-			continue
-		}
-		ips, err := s.queryIPTimeout(idx, client, domain, option)
-		if len(ips) > 0 {
-			return ips, nil
-		}
-
-		if err != nil {
-			newError("failed to lookup ip for domain ", domain, " at server ", client.Name()).Base(err).WriteToLog()
-			lastErr = err
-		}
-		if err != context.Canceled && err != context.DeadlineExceeded && err != errExpectedIPNonMatch {
-			return nil, err
-		}
-	}
-
-	return nil, newError("returning nil for domain ", domain).Base(lastErr)
-}
-
-func init() {
-	common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
-		return New(ctx, config.(*Config))
-	}))
-}

app/router/command/config.go

@@ -28,6 +28,12 @@ func (c routingContext) GetTargetPort() net.Port {
 	return net.Port(c.RoutingContext.GetTargetPort())
 }
 
+// GetSkipDNSResolve is a mock implementation here to match the interface,
+// SkipDNSResolve is set from dns module, no use if coming from a protobuf object?
+func (c routingContext) GetSkipDNSResolve() bool {
+	return false
+}
+
 // AsRoutingContext converts a protobuf RoutingContext into an implementation of routing.Context.
 func AsRoutingContext(r *RoutingContext) routing.Context {
 	return routingContext{r}

app/router/router.go

@@ -80,7 +80,13 @@ func (r *Router) PickRoute(ctx routing.Context) (routing.Route, error) {
 }
 
 func (r *Router) pickRouteInternal(ctx routing.Context) (*Rule, routing.Context, error) {
-	if r.domainStrategy == Config_IpOnDemand {
+
+	// SkipDNSResolve is set from DNS module.
+	// the DOH remote server maybe a domain name,
+	// this prevents cycle resolving dead loop
+	skipDNSResolve := ctx.GetSkipDNSResolve()
+
+	if r.domainStrategy == Config_IpOnDemand && !skipDNSResolve {
 		ctx = routing_dns.ContextWithDNSClient(ctx, r.dns)
 	}
 
@@ -90,7 +96,7 @@ func (r *Router) pickRouteInternal(ctx routing.Context) (*Rule, routing.Context,
 		}
 	}
 
-	if r.domainStrategy != Config_IpIfNonMatch || len(ctx.GetTargetDomain()) == 0 {
+	if r.domainStrategy != Config_IpIfNonMatch || len(ctx.GetTargetDomain()) == 0 || skipDNSResolve {
 		return nil, ctx, common.ErrNoClue
 	}
 

app/router/router_test.go

@@ -9,7 +9,6 @@ import (
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/common/session"
-	"github.com/xtls/xray-core/features/dns"
 	"github.com/xtls/xray-core/features/outbound"
 	routing_session "github.com/xtls/xray-core/features/routing/session"
 	"github.com/xtls/xray-core/testing/mocks"
@@ -116,11 +115,7 @@ func TestIPOnDemand(t *testing.T) {
 	defer mockCtl.Finish()
 
 	mockDNS := mocks.NewDNSClient(mockCtl)
-	mockDNS.EXPECT().LookupIP(gomock.Eq("example.com"), dns.IPOption{
-		IPv4Enable: true,
-		IPv6Enable: true,
-		FakeEnable: false,
-	}).Return([]net.IP{{192, 168, 0, 1}}, nil).AnyTimes()
+	mockDNS.EXPECT().LookupIP(gomock.Eq("example.com")).Return([]net.IP{{192, 168, 0, 1}}, nil).AnyTimes()
 
 	r := new(Router)
 	common.Must(r.Init(config, mockDNS, nil))
@@ -155,11 +150,7 @@ func TestIPIfNonMatchDomain(t *testing.T) {
 	defer mockCtl.Finish()
 
 	mockDNS := mocks.NewDNSClient(mockCtl)
-	mockDNS.EXPECT().LookupIP(gomock.Eq("example.com"), dns.IPOption{
-		IPv4Enable: true,
-		IPv6Enable: true,
-		FakeEnable: false,
-	}).Return([]net.IP{{192, 168, 0, 1}}, nil).AnyTimes()
+	mockDNS.EXPECT().LookupIP(gomock.Eq("example.com")).Return([]net.IP{{192, 168, 0, 1}}, nil).AnyTimes()
 
 	r := new(Router)
 	common.Must(r.Init(config, mockDNS, nil))

common/session/session.go

@@ -75,7 +75,7 @@ type Content struct {
 
 	Attributes map[string]string
 
-	SkipRoutePick bool
+	SkipDNSResolve bool
 }
 
 // Sockopt is the settings for socket connection.

features/dns/client.go

@@ -14,6 +14,12 @@ type IPOption struct {
 	FakeEnable bool
 }
 
+func (p *IPOption) Copy() *IPOption {
+	return &IPOption{p.IPv4Enable, p.IPv6Enable, p.FakeEnable}
+}
+
+type Option func(dopt *IPOption) *IPOption
+
 // Client is a Xray feature for querying DNS information.
 //
 // xray:api:stable
@@ -21,7 +27,24 @@ type Client interface {
 	features.Feature
 
 	// LookupIP returns IP address for the given domain. IPs may contain IPv4 and/or IPv6 addresses.
-	LookupIP(domain string, option IPOption) ([]net.IP, error)
+	LookupIP(domain string) ([]net.IP, error)
+
+	// LookupOptions query IP address for domain with *IPOption.
+	LookupOptions(domain string, opt ...Option) ([]net.IP, error)
+}
+
+// IPv4Lookup is an optional feature for querying IPv4 addresses only.
+//
+// xray:api:beta
+type IPv4Lookup interface {
+	LookupIPv4(domain string) ([]net.IP, error)
+}
+
+// IPv6Lookup is an optional feature for querying IPv6 addresses only.
+//
+// xray:api:beta
+type IPv6Lookup interface {
+	LookupIPv6(domain string) ([]net.IP, error)
 }
 
 // ClientType returns the type of Client interface. Can be used for implementing common.HasType.
@@ -50,3 +73,41 @@ func RCodeFromError(err error) uint16 {
 	}
 	return 0
 }
+
+var (
+	LookupIPv4Only = func(d *IPOption) *IPOption {
+		d.IPv4Enable = true
+		d.IPv6Enable = false
+		return d
+	}
+	LookupIPv6Only = func(d *IPOption) *IPOption {
+		d.IPv4Enable = false
+		d.IPv6Enable = true
+		return d
+	}
+	LookupIP = func(d *IPOption) *IPOption {
+		d.IPv4Enable = true
+		d.IPv6Enable = true
+		return d
+	}
+	LookupFake = func(d *IPOption) *IPOption {
+		d.FakeEnable = true
+		return d
+	}
+	LookupFakeOnly = func(d *IPOption) *IPOption {
+		d.FakeEnable = true
+		d.IPv4Enable = false
+		d.IPv6Enable = false
+		return d
+	}
+	LookupNoFake = func(d *IPOption) *IPOption {
+		d.FakeEnable = false
+		return d
+	}
+
+	LookupAll = func(d *IPOption) *IPOption {
+		LookupIP(d)
+		LookupFake(d)
+		return d
+	}
+)

features/dns/localdns/client.go

@@ -20,41 +20,64 @@ func (*Client) Start() error { return nil }
 func (*Client) Close() error { return nil }
 
 // LookupIP implements Client.
-func (*Client) LookupIP(host string, option dns.IPOption) ([]net.IP, error) {
+func (*Client) LookupIP(host string) ([]net.IP, error) {
 	ips, err := net.LookupIP(host)
 	if err != nil {
 		return nil, err
 	}
 	parsedIPs := make([]net.IP, 0, len(ips))
-	ipv4 := make([]net.IP, 0, len(ips))
-	ipv6 := make([]net.IP, 0, len(ips))
 	for _, ip := range ips {
 		parsed := net.IPAddress(ip)
 		if parsed != nil {
 			parsedIPs = append(parsedIPs, parsed.IP())
 		}
+	}
+	if len(parsedIPs) == 0 {
+		return nil, dns.ErrEmptyResponse
+	}
+	return parsedIPs, nil
+}
+
+// LookupOptions implements Client.
+func (c *Client) LookupOptions(host string, _ ...dns.Option) ([]net.IP, error) {
+	return c.LookupIP(host)
+}
+
+// LookupIPv4 implements IPv4Lookup.
+func (c *Client) LookupIPv4(host string) ([]net.IP, error) {
+	ips, err := c.LookupIP(host)
+	if err != nil {
+		return nil, err
+	}
+	ipv4 := make([]net.IP, 0, len(ips))
+	for _, ip := range ips {
 		if len(ip) == net.IPv4len {
 			ipv4 = append(ipv4, ip)
 		}
+	}
+	if len(ipv4) == 0 {
+		return nil, dns.ErrEmptyResponse
+	}
+	return ipv4, nil
+}
+
+// LookupIPv6 implements IPv6Lookup.
+func (c *Client) LookupIPv6(host string) ([]net.IP, error) {
+	ips, err := c.LookupIP(host)
+	if err != nil {
+		return nil, err
+	}
+	ipv6 := make([]net.IP, 0, len(ips))
+	for _, ip := range ips {
 		if len(ip) == net.IPv6len {
 			ipv6 = append(ipv6, ip)
 		}
 	}
-	switch {
-	case option.IPv4Enable && option.IPv6Enable:
-		if len(parsedIPs) > 0 {
-			return parsedIPs, nil
-		}
-	case option.IPv4Enable:
-		if len(ipv4) > 0 {
-			return ipv4, nil
-		}
-	case option.IPv6Enable:
-		if len(ipv6) > 0 {
-			return ipv6, nil
-		}
-	}
+	if len(ipv6) == 0 {
 		return nil, dns.ErrEmptyResponse
+	}
+
+	return ipv6, nil
 }
 
 // New create a new dns.Client that queries localhost for DNS.

features/routing/context.go

@@ -37,4 +37,7 @@ type Context interface {
 
 	// GetAttributes returns extra attributes from the conneciont content.
 	GetAttributes() map[string]string
+
+	// GetSkipDNSResolve returns a flag switch for weather skip dns resolve during route pick.
+	GetSkipDNSResolve() bool
 }

features/routing/dns/context.go

@@ -26,16 +26,12 @@ func (ctx *ResolvableContext) GetTargetIPs() []net.IP {
 	}
 
 	if domain := ctx.GetTargetDomain(); len(domain) != 0 {
-		ips, err := ctx.dnsClient.LookupIP(domain, dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: true,
-			FakeEnable: false,
-		})
+		ips, err := ctx.dnsClient.LookupIP(domain)
 		if err == nil {
 			ctx.resolvedIPs = ips
 			return ips
 		}
-		newError("resolve ip for ", domain).Base(err).WriteToLog()
+		newError("failed to resolve ip for ", domain).Base(err).WriteToLog()
 	}
 
 	return nil

features/routing/session/context.go

@@ -109,6 +109,14 @@ func (ctx *Context) GetAttributes() map[string]string {
 	return ctx.Content.Attributes
 }
 
+// GetSkipDNSResolve implements routing.Context.
+func (ctx *Context) GetSkipDNSResolve() bool {
+	if ctx.Content == nil {
+		return false
+	}
+	return ctx.Content.SkipDNSResolve
+}
+
 // AsRoutingContext creates a context from context.context with session info.
 func AsRoutingContext(ctx context.Context) routing.Context {
 	return &Context{

infra/conf/dns.go

@@ -12,7 +12,9 @@ import (
 
 type NameServerConfig struct {
 	Address      *Address
+	ClientIP     *Address
 	Port         uint16
+	SkipFallback bool
 	Domains      []string
 	ExpectIPs    StringList
 }
@@ -26,13 +28,17 @@ func (c *NameServerConfig) UnmarshalJSON(data []byte) error {
 
 	var advanced struct {
 		Address      *Address   `json:"address"`
+		ClientIP     *Address   `json:"clientIp"`
 		Port         uint16     `json:"port"`
+		SkipFallback bool       `json:"skipFallback"`
 		Domains      []string   `json:"domains"`
 		ExpectIPs    StringList `json:"expectIps"`
 	}
 	if err := json.Unmarshal(data, &advanced); err == nil {
 		c.Address = advanced.Address
+		c.ClientIP = advanced.ClientIP
 		c.Port = advanced.Port
+		c.SkipFallback = advanced.SkipFallback
 		c.Domains = advanced.Domains
 		c.ExpectIPs = advanced.ExpectIPs
 		return nil
@@ -87,12 +93,21 @@ func (c *NameServerConfig) Build() (*dns.NameServer, error) {
 		return nil, newError("invalid IP rule: ", c.ExpectIPs).Base(err)
 	}
 
+	var myClientIP []byte
+	if c.ClientIP != nil {
+		if !c.ClientIP.Family().IsIP() {
+			return nil, newError("not an IP address:", c.ClientIP.String())
+		}
+		myClientIP = []byte(c.ClientIP.IP())
+	}
 	return &dns.NameServer{
 		Address: &net.Endpoint{
 			Network: net.Network_UDP,
 			Address: c.Address.Build(),
 			Port:    uint32(c.Port),
 		},
+		ClientIp:          myClientIP,
+		SkipFallback:      c.SkipFallback,
 		PrioritizedDomain: domains,
 		Geoip:             geoipList,
 		OriginalRules:     originalRules,
@@ -109,27 +124,71 @@ var typeMap = map[router.Domain_Type]dns.DomainMatchingType{
 // DNSConfig is a JSON serializable object for dns.Config.
 type DNSConfig struct {
 	Servers         []*NameServerConfig     `json:"servers"`
-	Hosts    map[string]*Address `json:"hosts"`
+	Hosts           map[string]*HostAddress `json:"hosts"`
 	ClientIP        *Address                `json:"clientIp"`
 	Tag             string                  `json:"tag"`
+	QueryStrategy   string                  `json:"queryStrategy"`
+	CacheStrategy   string                  `json:"cacheStrategy"`
+	DisableCache    bool                    `json:"disableCache"`
+	DisableFallback bool                    `json:"disableFallback"`
 }
 
-func getHostMapping(addr *Address) *dns.Config_HostMapping {
-	if addr.Family().IsIP() {
-		return &dns.Config_HostMapping{
-			Ip: [][]byte{[]byte(addr.IP())},
+type HostAddress struct {
+	addr  *Address
+	addrs []*Address
+}
+
+// UnmarshalJSON implements encoding/json.Unmarshaler.UnmarshalJSON
+func (h *HostAddress) UnmarshalJSON(data []byte) error {
+	addr := new(Address)
+	var addrs []*Address
+	switch {
+	case json.Unmarshal(data, &addr) == nil:
+		h.addr = addr
+	case json.Unmarshal(data, &addrs) == nil:
+		h.addrs = addrs
+	default:
+		return newError("invalid address")
 	}
-	} else {
+	return nil
+}
+
+func getHostMapping(ha *HostAddress) *dns.Config_HostMapping {
+	if ha.addr != nil {
+		if ha.addr.Family().IsDomain() {
+			return &dns.Config_HostMapping{
+				ProxiedDomain: ha.addr.Domain(),
+			}
+		}
+		return &dns.Config_HostMapping{
+			Ip: [][]byte{ha.addr.IP()},
+		}
+	}
+
+	ips := make([][]byte, 0, len(ha.addrs))
+	for _, addr := range ha.addrs {
+		if addr.Family().IsDomain() {
 			return &dns.Config_HostMapping{
 				ProxiedDomain: addr.Domain(),
 			}
 		}
+		ips = append(ips, []byte(addr.IP()))
+	}
+	return &dns.Config_HostMapping{
+		Ip: ips,
+	}
 }
 
 // Build implements Buildable
 func (c *DNSConfig) Build() (*dns.Config, error) {
 	config := &dns.Config{
 		Tag:             c.Tag,
+		CacheStrategy:   dns.CacheStrategy_Cache_ALL,
+		DisableFallback: c.DisableFallback,
+	}
+
+	if c.DisableCache {
+		config.CacheStrategy = dns.CacheStrategy_Cache_DISABLE
 	}
 
 	if c.ClientIP != nil {
@@ -139,6 +198,25 @@ func (c *DNSConfig) Build() (*dns.Config, error) {
 		config.ClientIp = []byte(c.ClientIP.IP())
 	}
 
+	config.QueryStrategy = dns.QueryStrategy_USE_IP
+	switch strings.ToLower(c.QueryStrategy) {
+	case "useip", "use_ip", "use-ip":
+		config.QueryStrategy = dns.QueryStrategy_USE_IP
+	case "useip4", "useipv4", "use_ip4", "use_ipv4", "use_ip_v4", "use-ip4", "use-ipv4", "use-ip-v4":
+		config.QueryStrategy = dns.QueryStrategy_USE_IP4
+	case "useip6", "useipv6", "use_ip6", "use_ipv6", "use_ip_v6", "use-ip6", "use-ipv6", "use-ip-v6":
+		config.QueryStrategy = dns.QueryStrategy_USE_IP6
+	}
+
+	switch strings.ToLower(c.CacheStrategy) {
+	case "noerror":
+		config.CacheStrategy = dns.CacheStrategy_Cache_NOERROR
+	case "all":
+		config.CacheStrategy = dns.CacheStrategy_Cache_ALL
+	case "disable", "none":
+		config.CacheStrategy = dns.CacheStrategy_Cache_DISABLE
+	}
+
 	for _, server := range c.Servers {
 		ns, err := server.Build()
 		if err != nil {

infra/conf/dns_proxy.go

@@ -1,6 +1,8 @@
 package conf
 
 import (
+	"strings"
+
 	"github.com/golang/protobuf/proto"
 	"github.com/xtls/xray-core/common/net"
 	"github.com/xtls/xray-core/proxy/dns"
@@ -10,6 +12,7 @@ type DNSOutboundConfig struct {
 	Network        Network  `json:"network"`
 	Address        *Address `json:"address"`
 	Port           uint16   `json:"port"`
+	DomainStrategy string   `json:"domainStrategy"`
 }
 
 func (c *DNSOutboundConfig) Build() (proto.Message, error) {
@@ -22,5 +25,12 @@ func (c *DNSOutboundConfig) Build() (proto.Message, error) {
 	if c.Address != nil {
 		config.Server.Address = c.Address.Build()
 	}
+	config.DomainStrategy = dns.Config_USE_ALL
+	switch strings.ToLower(c.DomainStrategy) {
+	case "useip", "use_ip", "use-ip":
+		config.DomainStrategy = dns.Config_USE_IP
+	case "fake", "fakedns":
+		config.DomainStrategy = dns.Config_USE_FAKE
+	}
 	return config, nil
 }

infra/conf/dns_proxy_test.go

@@ -27,6 +27,7 @@ func TestDnsProxyConfig(t *testing.T) {
 					Address: net.NewIPOrDomain(net.IPAddress([]byte{8, 8, 8, 8})),
 					Port:    53,
 				},
+				DomainStrategy: dns.Config_USE_ALL,
 			},
 		},
 	})

infra/conf/dns_test.go

@@ -67,17 +67,23 @@ func TestDNSConfigParsing(t *testing.T) {
 			Input: `{
 				"servers": [{
 					"address": "8.8.8.8",
+					"clientIp": "10.0.0.1",
 					"port": 5353,
+					"skipFallback": true,
 					"domains": ["domain:example.com"]
 				}],
 				"hosts": {
 					"example.com": "127.0.0.1",
+					"xtls.github.io": ["1.2.3.4", "5.6.7.8"],
 					"domain:example.com": "google.com",
-					"geosite:test": "10.0.0.1",
-					"keyword:google": "8.8.8.8",
+					"geosite:test": ["127.0.0.1", "127.0.0.2"],
+					"keyword:google": ["8.8.8.8", "8.8.4.4"],
 					"regexp:.*\\.com": "8.8.4.4"
 				},
-				"clientIp": "10.0.0.1"
+				"clientIp": "10.0.0.1",
+				"queryStrategy": "UseIPv4",
+				"cacheStrategy": "disable",
+				"disableFallback": true
 			}`,
 			Parser: parserCreator(),
 			Output: &dns.Config{
@@ -92,6 +98,8 @@ func TestDNSConfigParsing(t *testing.T) {
 							Network: net.Network_UDP,
 							Port:    5353,
 						},
+						ClientIp:     []byte{10, 0, 0, 1},
+						SkipFallback: true,
 						PrioritizedDomain: []*dns.NameServer_PriorityDomain{
 							{
 								Type:   dns.DomainMatchingType_Subdomain,
@@ -120,20 +128,28 @@ func TestDNSConfigParsing(t *testing.T) {
 					{
 						Type:   dns.DomainMatchingType_Full,
 						Domain: "example.com",
-						Ip:     [][]byte{{10, 0, 0, 1}},
+						Ip:     [][]byte{{127, 0, 0, 1}, {127, 0, 0, 2}},
 					},
 					{
 						Type:   dns.DomainMatchingType_Keyword,
 						Domain: "google",
-						Ip:     [][]byte{{8, 8, 8, 8}},
+						Ip:     [][]byte{{8, 8, 8, 8}, {8, 8, 4, 4}},
 					},
 					{
 						Type:   dns.DomainMatchingType_Regex,
 						Domain: ".*\\.com",
 						Ip:     [][]byte{{8, 8, 4, 4}},
 					},
+					{
+						Type:   dns.DomainMatchingType_Full,
+						Domain: "xtls.github.io",
+						Ip:     [][]byte{{1, 2, 3, 4}, {5, 6, 7, 8}},
+					},
 				},
 				ClientIp:        []byte{10, 0, 0, 1},
+				QueryStrategy:   dns.QueryStrategy_USE_IP4,
+				CacheStrategy:   dns.CacheStrategy_Cache_DISABLE,
+				DisableFallback: true,
 			},
 		},
 	})

infra/conf/freedom.go

@@ -22,11 +22,11 @@ func (c *FreedomConfig) Build() (proto.Message, error) {
 	config := new(freedom.Config)
 	config.DomainStrategy = freedom.Config_AS_IS
 	switch strings.ToLower(c.DomainStrategy) {
-	case "useip", "use_ip":
+	case "useip", "use_ip", "use-ip":
 		config.DomainStrategy = freedom.Config_USE_IP
-	case "useip4", "useipv4", "use_ipv4", "use_ip_v4", "use_ip4":
+	case "useip4", "useipv4", "use_ip4", "use_ipv4", "use_ip_v4", "use-ip4", "use-ipv4", "use-ip-v4":
 		config.DomainStrategy = freedom.Config_USE_IP4
-	case "useip6", "useipv6", "use_ipv6", "use_ip_v6", "use_ip6":
+	case "useip6", "useipv6", "use_ip6", "use_ipv6", "use_ip_v6", "use-ip6", "use-ipv6", "use-ip-v6":
 		config.DomainStrategy = freedom.Config_USE_IP6
 	}
 

proxy/dns/config.pb.go

@@ -1,7 +1,7 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
 // 	protoc-gen-go v1.25.0
-// 	protoc        v3.14.0
+// 	protoc        v3.15.8
 // source: proxy/dns/config.proto
 
 package dns
@@ -26,6 +26,55 @@ const (
 // of the legacy proto package is being used.
 const _ = proto.ProtoPackageIsVersion4
 
+type Config_DomainStrategy int32
+
+const (
+	Config_USE_ALL  Config_DomainStrategy = 0
+	Config_USE_IP   Config_DomainStrategy = 1
+	Config_USE_FAKE Config_DomainStrategy = 2
+)
+
+// Enum value maps for Config_DomainStrategy.
+var (
+	Config_DomainStrategy_name = map[int32]string{
+		0: "USE_ALL",
+		1: "USE_IP",
+		2: "USE_FAKE",
+	}
+	Config_DomainStrategy_value = map[string]int32{
+		"USE_ALL":  0,
+		"USE_IP":   1,
+		"USE_FAKE": 2,
+	}
+)
+
+func (x Config_DomainStrategy) Enum() *Config_DomainStrategy {
+	p := new(Config_DomainStrategy)
+	*p = x
+	return p
+}
+
+func (x Config_DomainStrategy) String() string {
+	return protoimpl.X.EnumStringOf(x.Descriptor(), protoreflect.EnumNumber(x))
+}
+
+func (Config_DomainStrategy) Descriptor() protoreflect.EnumDescriptor {
+	return file_proxy_dns_config_proto_enumTypes[0].Descriptor()
+}
+
+func (Config_DomainStrategy) Type() protoreflect.EnumType {
+	return &file_proxy_dns_config_proto_enumTypes[0]
+}
+
+func (x Config_DomainStrategy) Number() protoreflect.EnumNumber {
+	return protoreflect.EnumNumber(x)
+}
+
+// Deprecated: Use Config_DomainStrategy.Descriptor instead.
+func (Config_DomainStrategy) EnumDescriptor() ([]byte, []int) {
+	return file_proxy_dns_config_proto_rawDescGZIP(), []int{0, 0}
+}
+
 type Config struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -34,6 +83,7 @@ type Config struct {
 	// Server is the DNS server address. If specified, this address overrides the
 	// original one.
 	Server         *net.Endpoint         `protobuf:"bytes,1,opt,name=server,proto3" json:"server,omitempty"`
+	DomainStrategy Config_DomainStrategy `protobuf:"varint,2,opt,name=domain_strategy,json=domainStrategy,proto3,enum=xray.proxy.dns.Config_DomainStrategy" json:"domain_strategy,omitempty"`
 }
 
 func (x *Config) Reset() {
@@ -75,6 +125,13 @@ func (x *Config) GetServer() *net.Endpoint {
 	return nil
 }
 
+func (x *Config) GetDomainStrategy() Config_DomainStrategy {
+	if x != nil {
+		return x.DomainStrategy
+	}
+	return Config_USE_ALL
+}
+
 var File_proxy_dns_config_proto protoreflect.FileDescriptor
 
 var file_proxy_dns_config_proto_rawDesc = []byte{
@@ -82,16 +139,25 @@ var file_proxy_dns_config_proto_rawDesc = []byte{
 	0x69, 0x67, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x12, 0x0e, 0x78, 0x72, 0x61, 0x79, 0x2e, 0x70,
 	0x72, 0x6f, 0x78, 0x79, 0x2e, 0x64, 0x6e, 0x73, 0x1a, 0x1c, 0x63, 0x6f, 0x6d, 0x6d, 0x6f, 0x6e,
 	0x2f, 0x6e, 0x65, 0x74, 0x2f, 0x64, 0x65, 0x73, 0x74, 0x69, 0x6e, 0x61, 0x74, 0x69, 0x6f, 0x6e,
-	0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22, 0x3b, 0x0a, 0x06, 0x43, 0x6f, 0x6e, 0x66, 0x69, 0x67,
-	0x12, 0x31, 0x0a, 0x06, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0b,
-	0x32, 0x19, 0x2e, 0x78, 0x72, 0x61, 0x79, 0x2e, 0x63, 0x6f, 0x6d, 0x6d, 0x6f, 0x6e, 0x2e, 0x6e,
-	0x65, 0x74, 0x2e, 0x45, 0x6e, 0x64, 0x70, 0x6f, 0x69, 0x6e, 0x74, 0x52, 0x06, 0x73, 0x65, 0x72,
-	0x76, 0x65, 0x72, 0x42, 0x4c, 0x0a, 0x12, 0x63, 0x6f, 0x6d, 0x2e, 0x78, 0x72, 0x61, 0x79, 0x2e,
-	0x70, 0x72, 0x6f, 0x78, 0x79, 0x2e, 0x64, 0x6e, 0x73, 0x50, 0x01, 0x5a, 0x23, 0x67, 0x69, 0x74,
-	0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x78, 0x74, 0x6c, 0x73, 0x2f, 0x78, 0x72, 0x61,
-	0x79, 0x2d, 0x63, 0x6f, 0x72, 0x65, 0x2f, 0x70, 0x72, 0x6f, 0x78, 0x79, 0x2f, 0x64, 0x6e, 0x73,
-	0xaa, 0x02, 0x0e, 0x58, 0x72, 0x61, 0x79, 0x2e, 0x50, 0x72, 0x6f, 0x78, 0x79, 0x2e, 0x44, 0x6e,
-	0x73, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+	0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22, 0xc4, 0x01, 0x0a, 0x06, 0x43, 0x6f, 0x6e, 0x66, 0x69,
+	0x67, 0x12, 0x31, 0x0a, 0x06, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x18, 0x01, 0x20, 0x01, 0x28,
+	0x0b, 0x32, 0x19, 0x2e, 0x78, 0x72, 0x61, 0x79, 0x2e, 0x63, 0x6f, 0x6d, 0x6d, 0x6f, 0x6e, 0x2e,
+	0x6e, 0x65, 0x74, 0x2e, 0x45, 0x6e, 0x64, 0x70, 0x6f, 0x69, 0x6e, 0x74, 0x52, 0x06, 0x73, 0x65,
+	0x72, 0x76, 0x65, 0x72, 0x12, 0x4e, 0x0a, 0x0f, 0x64, 0x6f, 0x6d, 0x61, 0x69, 0x6e, 0x5f, 0x73,
+	0x74, 0x72, 0x61, 0x74, 0x65, 0x67, 0x79, 0x18, 0x02, 0x20, 0x01, 0x28, 0x0e, 0x32, 0x25, 0x2e,
+	0x78, 0x72, 0x61, 0x79, 0x2e, 0x70, 0x72, 0x6f, 0x78, 0x79, 0x2e, 0x64, 0x6e, 0x73, 0x2e, 0x43,
+	0x6f, 0x6e, 0x66, 0x69, 0x67, 0x2e, 0x44, 0x6f, 0x6d, 0x61, 0x69, 0x6e, 0x53, 0x74, 0x72, 0x61,
+	0x74, 0x65, 0x67, 0x79, 0x52, 0x0e, 0x64, 0x6f, 0x6d, 0x61, 0x69, 0x6e, 0x53, 0x74, 0x72, 0x61,
+	0x74, 0x65, 0x67, 0x79, 0x22, 0x37, 0x0a, 0x0e, 0x44, 0x6f, 0x6d, 0x61, 0x69, 0x6e, 0x53, 0x74,
+	0x72, 0x61, 0x74, 0x65, 0x67, 0x79, 0x12, 0x0b, 0x0a, 0x07, 0x55, 0x53, 0x45, 0x5f, 0x41, 0x4c,
+	0x4c, 0x10, 0x00, 0x12, 0x0a, 0x0a, 0x06, 0x55, 0x53, 0x45, 0x5f, 0x49, 0x50, 0x10, 0x01, 0x12,
+	0x0c, 0x0a, 0x08, 0x55, 0x53, 0x45, 0x5f, 0x46, 0x41, 0x4b, 0x45, 0x10, 0x02, 0x42, 0x4c, 0x0a,
+	0x12, 0x63, 0x6f, 0x6d, 0x2e, 0x78, 0x72, 0x61, 0x79, 0x2e, 0x70, 0x72, 0x6f, 0x78, 0x79, 0x2e,
+	0x64, 0x6e, 0x73, 0x50, 0x01, 0x5a, 0x23, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f,
+	0x6d, 0x2f, 0x78, 0x74, 0x6c, 0x73, 0x2f, 0x78, 0x72, 0x61, 0x79, 0x2d, 0x63, 0x6f, 0x72, 0x65,
+	0x2f, 0x70, 0x72, 0x6f, 0x78, 0x79, 0x2f, 0x64, 0x6e, 0x73, 0xaa, 0x02, 0x0e, 0x58, 0x72, 0x61,
+	0x79, 0x2e, 0x50, 0x72, 0x6f, 0x78, 0x79, 0x2e, 0x44, 0x6e, 0x73, 0x62, 0x06, 0x70, 0x72, 0x6f,
+	0x74, 0x6f, 0x33,
 }
 
 var (
@@ -106,18 +172,21 @@ func file_proxy_dns_config_proto_rawDescGZIP() []byte {
 	return file_proxy_dns_config_proto_rawDescData
 }
 
+var file_proxy_dns_config_proto_enumTypes = make([]protoimpl.EnumInfo, 1)
 var file_proxy_dns_config_proto_msgTypes = make([]protoimpl.MessageInfo, 1)
 var file_proxy_dns_config_proto_goTypes = []interface{}{
-	(*Config)(nil),       // 0: xray.proxy.dns.Config
-	(*net.Endpoint)(nil), // 1: xray.common.net.Endpoint
+	(Config_DomainStrategy)(0), // 0: xray.proxy.dns.Config.DomainStrategy
+	(*Config)(nil),             // 1: xray.proxy.dns.Config
+	(*net.Endpoint)(nil),       // 2: xray.common.net.Endpoint
 }
 var file_proxy_dns_config_proto_depIdxs = []int32{
-	1, // 0: xray.proxy.dns.Config.server:type_name -> xray.common.net.Endpoint
-	1, // [1:1] is the sub-list for method output_type
-	1, // [1:1] is the sub-list for method input_type
-	1, // [1:1] is the sub-list for extension type_name
-	1, // [1:1] is the sub-list for extension extendee
-	0, // [0:1] is the sub-list for field type_name
+	2, // 0: xray.proxy.dns.Config.server:type_name -> xray.common.net.Endpoint
+	0, // 1: xray.proxy.dns.Config.domain_strategy:type_name -> xray.proxy.dns.Config.DomainStrategy
+	2, // [2:2] is the sub-list for method output_type
+	2, // [2:2] is the sub-list for method input_type
+	2, // [2:2] is the sub-list for extension type_name
+	2, // [2:2] is the sub-list for extension extendee
+	0, // [0:2] is the sub-list for field type_name
 }
 
 func init() { file_proxy_dns_config_proto_init() }
@@ -144,13 +213,14 @@ func file_proxy_dns_config_proto_init() {
 		File: protoimpl.DescBuilder{
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_proxy_dns_config_proto_rawDesc,
-			NumEnums:      0,
+			NumEnums:      1,
 			NumMessages:   1,
 			NumExtensions: 0,
 			NumServices:   0,
 		},
 		GoTypes:           file_proxy_dns_config_proto_goTypes,
 		DependencyIndexes: file_proxy_dns_config_proto_depIdxs,
+		EnumInfos:         file_proxy_dns_config_proto_enumTypes,
 		MessageInfos:      file_proxy_dns_config_proto_msgTypes,
 	}.Build()
 	File_proxy_dns_config_proto = out.File

proxy/dns/config.proto

@@ -12,4 +12,10 @@ message Config {
   // Server is the DNS server address. If specified, this address overrides the
   // original one.
   xray.common.net.Endpoint server = 1;
+  enum DomainStrategy {
+    USE_ALL = 0;
+    USE_IP = 1;
+    USE_FAKE = 2;
+  }
+  DomainStrategy domain_strategy = 2;
 }

proxy/dns/dns.go

@@ -39,10 +39,12 @@ type Handler struct {
 	client          dns.Client
 	ownLinkVerifier ownLinkVerifier
 	server          net.Destination
+	DomainStrategy  Config_DomainStrategy
 }
 
 func (h *Handler) Init(config *Config, dnsClient dns.Client) error {
 	h.client = dnsClient
+
 	if v, ok := dnsClient.(ownLinkVerifier); ok {
 		h.ownLinkVerifier = v
 	}
@@ -198,22 +200,24 @@ func (h *Handler) handleIPQuery(id uint16, qType dnsmessage.Type, domain string,
 	var err error
 
 	var ttl uint32 = 600
+	var opt []dns.Option
 
+	if h.DomainStrategy == Config_USE_FAKE {
+		opt = append(opt, dns.LookupFakeOnly)
+	} else {
 		switch qType {
 		case dnsmessage.TypeA:
-		ips, err = h.client.LookupIP(domain, dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: false,
-			FakeEnable: true,
-		})
+			opt = append(opt, dns.LookupIPv4Only)
 		case dnsmessage.TypeAAAA:
-		ips, err = h.client.LookupIP(domain, dns.IPOption{
-			IPv4Enable: false,
-			IPv6Enable: true,
-			FakeEnable: true,
-		})
+			opt = append(opt, dns.LookupIPv6Only)
+		}
 	}
 
+	if h.DomainStrategy == Config_USE_ALL {
+		opt = append(opt, dns.LookupFake)
+	}
+
+	ips, err = h.client.LookupOptions(domain, opt...)
 	rcode := dns.RCodeFromError(err)
 	if rcode == 0 && len(ips) == 0 && err != dns.ErrEmptyResponse {
 		newError("ip query").Base(err).WriteToLog()
@@ -228,7 +232,6 @@ func (h *Handler) handleIPQuery(id uint16, qType dnsmessage.Type, domain string,
 		RecursionAvailable: true,
 		RecursionDesired:   true,
 		Response:           true,
-		Authoritative:      true,
 	})
 	builder.EnableCompression()
 	common.Must(builder.StartQuestions())

proxy/freedom/freedom.go

@@ -59,26 +59,14 @@ func (h *Handler) policy() policy.Session {
 }
 
 func (h *Handler) resolveIP(ctx context.Context, domain string, localAddr net.Address) net.Address {
-	var option dns.IPOption = dns.IPOption{
-		IPv4Enable: true,
-		IPv6Enable: true,
-		FakeEnable: false,
-	}
+	var opt dns.Option
 	if h.config.DomainStrategy == Config_USE_IP4 || (localAddr != nil && localAddr.Family().IsIPv4()) {
-		option = dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: false,
-			FakeEnable: false,
-		}
+		opt = dns.LookupIPv4Only
 	} else if h.config.DomainStrategy == Config_USE_IP6 || (localAddr != nil && localAddr.Family().IsIPv6()) {
-		option = dns.IPOption{
-			IPv4Enable: false,
-			IPv6Enable: true,
-			FakeEnable: false,
-		}
+		opt = dns.LookupIPv6Only
 	}
 
-	ips, err := h.dns.LookupIP(domain, option)
+	ips, err := h.dns.LookupOptions(domain, opt, dns.LookupNoFake)
 	if err != nil {
 		newError("failed to get IP address for domain ", domain).Base(err).WriteToLog(session.ExportIDToError(ctx))
 	}

testing/mocks/dns.go

@@ -5,36 +5,37 @@
 package mocks
 
 import (
-	gomock "github.com/golang/mock/gomock"
-	dns "github.com/xtls/xray-core/features/dns"
 	net "net"
 	reflect "reflect"
+
+	gomock "github.com/golang/mock/gomock"
+	dns "github.com/xtls/xray-core/features/dns"
 )
 
-// DNSClient is a mock of Client interface
+// DNSClient is a mock of Client interface.
 type DNSClient struct {
 	ctrl     *gomock.Controller
 	recorder *DNSClientMockRecorder
 }
 
-// DNSClientMockRecorder is the mock recorder for DNSClient
+// DNSClientMockRecorder is the mock recorder for DNSClient.
 type DNSClientMockRecorder struct {
 	mock *DNSClient
 }
 
-// NewDNSClient creates a new mock instance
+// NewDNSClient creates a new mock instance.
 func NewDNSClient(ctrl *gomock.Controller) *DNSClient {
 	mock := &DNSClient{ctrl: ctrl}
 	mock.recorder = &DNSClientMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *DNSClient) EXPECT() *DNSClientMockRecorder {
 	return m.recorder
 }
 
-// Close mocks base method
+// Close mocks base method.
 func (m *DNSClient) Close() error {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Close")
@@ -42,28 +43,48 @@ func (m *DNSClient) Close() error {
 	return ret0
 }
 
-// Close indicates an expected call of Close
+// Close indicates an expected call of Close.
 func (mr *DNSClientMockRecorder) Close() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Close", reflect.TypeOf((*DNSClient)(nil).Close))
 }
 
-// LookupIP mocks base method
-func (m *DNSClient) LookupIP(arg0 string, arg1 dns.IPOption) ([]net.IP, error) {
+// LookupIP mocks base method.
+func (m *DNSClient) LookupIP(arg0 string) ([]net.IP, error) {
 	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "LookupIP", arg0, arg1)
+	ret := m.ctrl.Call(m, "LookupIP", arg0)
 	ret0, _ := ret[0].([]net.IP)
 	ret1, _ := ret[1].(error)
 	return ret0, ret1
 }
 
-// LookupIP indicates an expected call of LookupIP
-func (mr *DNSClientMockRecorder) LookupIP(arg0, arg1 interface{}) *gomock.Call {
+// LookupIP indicates an expected call of LookupIP.
+func (mr *DNSClientMockRecorder) LookupIP(arg0 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "LookupIP", reflect.TypeOf((*DNSClient)(nil).LookupIP), arg0, arg1)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "LookupIP", reflect.TypeOf((*DNSClient)(nil).LookupIP), arg0)
 }
 
-// Start mocks base method
+// LookupOptions mocks base method.
+func (m *DNSClient) LookupOptions(arg0 string, arg1 ...dns.Option) ([]net.IP, error) {
+	m.ctrl.T.Helper()
+	varargs := []interface{}{arg0}
+	for _, a := range arg1 {
+		varargs = append(varargs, a)
+	}
+	ret := m.ctrl.Call(m, "LookupOptions", varargs...)
+	ret0, _ := ret[0].([]net.IP)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// LookupOptions indicates an expected call of LookupOptions.
+func (mr *DNSClientMockRecorder) LookupOptions(arg0 interface{}, arg1 ...interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	varargs := append([]interface{}{arg0}, arg1...)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "LookupOptions", reflect.TypeOf((*DNSClient)(nil).LookupOptions), varargs...)
+}
+
+// Start mocks base method.
 func (m *DNSClient) Start() error {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Start")
@@ -71,13 +92,13 @@ func (m *DNSClient) Start() error {
 	return ret0
 }
 
-// Start indicates an expected call of Start
+// Start indicates an expected call of Start.
 func (mr *DNSClientMockRecorder) Start() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Start", reflect.TypeOf((*DNSClient)(nil).Start))
 }
 
-// Type mocks base method
+// Type mocks base method.
 func (m *DNSClient) Type() interface{} {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Type")
@@ -85,7 +106,7 @@ func (m *DNSClient) Type() interface{} {
 	return ret0
 }
 
-// Type indicates an expected call of Type
+// Type indicates an expected call of Type.
 func (mr *DNSClientMockRecorder) Type() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Type", reflect.TypeOf((*DNSClient)(nil).Type))

testing/mocks/io.go

@@ -5,34 +5,35 @@
 package mocks
 
 import (
-	gomock "github.com/golang/mock/gomock"
 	reflect "reflect"
+
+	gomock "github.com/golang/mock/gomock"
 )
 
-// Reader is a mock of Reader interface
+// Reader is a mock of Reader interface.
 type Reader struct {
 	ctrl     *gomock.Controller
 	recorder *ReaderMockRecorder
 }
 
-// ReaderMockRecorder is the mock recorder for Reader
+// ReaderMockRecorder is the mock recorder for Reader.
 type ReaderMockRecorder struct {
 	mock *Reader
 }
 
-// NewReader creates a new mock instance
+// NewReader creates a new mock instance.
 func NewReader(ctrl *gomock.Controller) *Reader {
 	mock := &Reader{ctrl: ctrl}
 	mock.recorder = &ReaderMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *Reader) EXPECT() *ReaderMockRecorder {
 	return m.recorder
 }
 
-// Read mocks base method
+// Read mocks base method.
 func (m *Reader) Read(arg0 []byte) (int, error) {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Read", arg0)
@@ -41,36 +42,36 @@ func (m *Reader) Read(arg0 []byte) (int, error) {
 	return ret0, ret1
 }
 
-// Read indicates an expected call of Read
+// Read indicates an expected call of Read.
 func (mr *ReaderMockRecorder) Read(arg0 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Read", reflect.TypeOf((*Reader)(nil).Read), arg0)
 }
 
-// Writer is a mock of Writer interface
+// Writer is a mock of Writer interface.
 type Writer struct {
 	ctrl     *gomock.Controller
 	recorder *WriterMockRecorder
 }
 
-// WriterMockRecorder is the mock recorder for Writer
+// WriterMockRecorder is the mock recorder for Writer.
 type WriterMockRecorder struct {
 	mock *Writer
 }
 
-// NewWriter creates a new mock instance
+// NewWriter creates a new mock instance.
 func NewWriter(ctrl *gomock.Controller) *Writer {
 	mock := &Writer{ctrl: ctrl}
 	mock.recorder = &WriterMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *Writer) EXPECT() *WriterMockRecorder {
 	return m.recorder
 }
 
-// Write mocks base method
+// Write mocks base method.
 func (m *Writer) Write(arg0 []byte) (int, error) {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Write", arg0)
@@ -79,7 +80,7 @@ func (m *Writer) Write(arg0 []byte) (int, error) {
 	return ret0, ret1
 }
 
-// Write indicates an expected call of Write
+// Write indicates an expected call of Write.
 func (mr *WriterMockRecorder) Write(arg0 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Write", reflect.TypeOf((*Writer)(nil).Write), arg0)

testing/mocks/log.go

@@ -5,41 +5,42 @@
 package mocks
 
 import (
+	reflect "reflect"
+
 	gomock "github.com/golang/mock/gomock"
 	log "github.com/xtls/xray-core/common/log"
-	reflect "reflect"
 )
 
-// LogHandler is a mock of Handler interface
+// LogHandler is a mock of Handler interface.
 type LogHandler struct {
 	ctrl     *gomock.Controller
 	recorder *LogHandlerMockRecorder
 }
 
-// LogHandlerMockRecorder is the mock recorder for LogHandler
+// LogHandlerMockRecorder is the mock recorder for LogHandler.
 type LogHandlerMockRecorder struct {
 	mock *LogHandler
 }
 
-// NewLogHandler creates a new mock instance
+// NewLogHandler creates a new mock instance.
 func NewLogHandler(ctrl *gomock.Controller) *LogHandler {
 	mock := &LogHandler{ctrl: ctrl}
 	mock.recorder = &LogHandlerMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *LogHandler) EXPECT() *LogHandlerMockRecorder {
 	return m.recorder
 }
 
-// Handle mocks base method
+// Handle mocks base method.
 func (m *LogHandler) Handle(arg0 log.Message) {
 	m.ctrl.T.Helper()
 	m.ctrl.Call(m, "Handle", arg0)
 }
 
-// Handle indicates an expected call of Handle
+// Handle indicates an expected call of Handle.
 func (mr *LogHandlerMockRecorder) Handle(arg0 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Handle", reflect.TypeOf((*LogHandler)(nil).Handle), arg0)

testing/mocks/mux.go

@@ -5,35 +5,36 @@
 package mocks
 
 import (
+	reflect "reflect"
+
 	gomock "github.com/golang/mock/gomock"
 	mux "github.com/xtls/xray-core/common/mux"
-	reflect "reflect"
 )
 
-// MuxClientWorkerFactory is a mock of ClientWorkerFactory interface
+// MuxClientWorkerFactory is a mock of ClientWorkerFactory interface.
 type MuxClientWorkerFactory struct {
 	ctrl     *gomock.Controller
 	recorder *MuxClientWorkerFactoryMockRecorder
 }
 
-// MuxClientWorkerFactoryMockRecorder is the mock recorder for MuxClientWorkerFactory
+// MuxClientWorkerFactoryMockRecorder is the mock recorder for MuxClientWorkerFactory.
 type MuxClientWorkerFactoryMockRecorder struct {
 	mock *MuxClientWorkerFactory
 }
 
-// NewMuxClientWorkerFactory creates a new mock instance
+// NewMuxClientWorkerFactory creates a new mock instance.
 func NewMuxClientWorkerFactory(ctrl *gomock.Controller) *MuxClientWorkerFactory {
 	mock := &MuxClientWorkerFactory{ctrl: ctrl}
 	mock.recorder = &MuxClientWorkerFactoryMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *MuxClientWorkerFactory) EXPECT() *MuxClientWorkerFactoryMockRecorder {
 	return m.recorder
 }
 
-// Create mocks base method
+// Create mocks base method.
 func (m *MuxClientWorkerFactory) Create() (*mux.ClientWorker, error) {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Create")
@@ -42,7 +43,7 @@ func (m *MuxClientWorkerFactory) Create() (*mux.ClientWorker, error) {
 	return ret0, ret1
 }
 
-// Create indicates an expected call of Create
+// Create indicates an expected call of Create.
 func (mr *MuxClientWorkerFactoryMockRecorder) Create() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Create", reflect.TypeOf((*MuxClientWorkerFactory)(nil).Create))

testing/mocks/outbound.go

@@ -6,35 +6,36 @@ package mocks
 
 import (
 	context "context"
+	reflect "reflect"
+
 	gomock "github.com/golang/mock/gomock"
 	outbound "github.com/xtls/xray-core/features/outbound"
-	reflect "reflect"
 )
 
-// OutboundManager is a mock of Manager interface
+// OutboundManager is a mock of Manager interface.
 type OutboundManager struct {
 	ctrl     *gomock.Controller
 	recorder *OutboundManagerMockRecorder
 }
 
-// OutboundManagerMockRecorder is the mock recorder for OutboundManager
+// OutboundManagerMockRecorder is the mock recorder for OutboundManager.
 type OutboundManagerMockRecorder struct {
 	mock *OutboundManager
 }
 
-// NewOutboundManager creates a new mock instance
+// NewOutboundManager creates a new mock instance.
 func NewOutboundManager(ctrl *gomock.Controller) *OutboundManager {
 	mock := &OutboundManager{ctrl: ctrl}
 	mock.recorder = &OutboundManagerMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *OutboundManager) EXPECT() *OutboundManagerMockRecorder {
 	return m.recorder
 }
 
-// AddHandler mocks base method
+// AddHandler mocks base method.
 func (m *OutboundManager) AddHandler(arg0 context.Context, arg1 outbound.Handler) error {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "AddHandler", arg0, arg1)
@@ -42,13 +43,13 @@ func (m *OutboundManager) AddHandler(arg0 context.Context, arg1 outbound.Handler
 	return ret0
 }
 
-// AddHandler indicates an expected call of AddHandler
+// AddHandler indicates an expected call of AddHandler.
 func (mr *OutboundManagerMockRecorder) AddHandler(arg0, arg1 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "AddHandler", reflect.TypeOf((*OutboundManager)(nil).AddHandler), arg0, arg1)
 }
 
-// Close mocks base method
+// Close mocks base method.
 func (m *OutboundManager) Close() error {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Close")
@@ -56,13 +57,13 @@ func (m *OutboundManager) Close() error {
 	return ret0
 }
 
-// Close indicates an expected call of Close
+// Close indicates an expected call of Close.
 func (mr *OutboundManagerMockRecorder) Close() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Close", reflect.TypeOf((*OutboundManager)(nil).Close))
 }
 
-// GetDefaultHandler mocks base method
+// GetDefaultHandler mocks base method.
 func (m *OutboundManager) GetDefaultHandler() outbound.Handler {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "GetDefaultHandler")
@@ -70,13 +71,13 @@ func (m *OutboundManager) GetDefaultHandler() outbound.Handler {
 	return ret0
 }
 
-// GetDefaultHandler indicates an expected call of GetDefaultHandler
+// GetDefaultHandler indicates an expected call of GetDefaultHandler.
 func (mr *OutboundManagerMockRecorder) GetDefaultHandler() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetDefaultHandler", reflect.TypeOf((*OutboundManager)(nil).GetDefaultHandler))
 }
 
-// GetHandler mocks base method
+// GetHandler mocks base method.
 func (m *OutboundManager) GetHandler(arg0 string) outbound.Handler {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "GetHandler", arg0)
@@ -84,13 +85,13 @@ func (m *OutboundManager) GetHandler(arg0 string) outbound.Handler {
 	return ret0
 }
 
-// GetHandler indicates an expected call of GetHandler
+// GetHandler indicates an expected call of GetHandler.
 func (mr *OutboundManagerMockRecorder) GetHandler(arg0 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "GetHandler", reflect.TypeOf((*OutboundManager)(nil).GetHandler), arg0)
 }
 
-// RemoveHandler mocks base method
+// RemoveHandler mocks base method.
 func (m *OutboundManager) RemoveHandler(arg0 context.Context, arg1 string) error {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "RemoveHandler", arg0, arg1)
@@ -98,13 +99,13 @@ func (m *OutboundManager) RemoveHandler(arg0 context.Context, arg1 string) error
 	return ret0
 }
 
-// RemoveHandler indicates an expected call of RemoveHandler
+// RemoveHandler indicates an expected call of RemoveHandler.
 func (mr *OutboundManagerMockRecorder) RemoveHandler(arg0, arg1 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "RemoveHandler", reflect.TypeOf((*OutboundManager)(nil).RemoveHandler), arg0, arg1)
 }
 
-// Start mocks base method
+// Start mocks base method.
 func (m *OutboundManager) Start() error {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Start")
@@ -112,13 +113,13 @@ func (m *OutboundManager) Start() error {
 	return ret0
 }
 
-// Start indicates an expected call of Start
+// Start indicates an expected call of Start.
 func (mr *OutboundManagerMockRecorder) Start() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Start", reflect.TypeOf((*OutboundManager)(nil).Start))
 }
 
-// Type mocks base method
+// Type mocks base method.
 func (m *OutboundManager) Type() interface{} {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Type")
@@ -126,36 +127,36 @@ func (m *OutboundManager) Type() interface{} {
 	return ret0
 }
 
-// Type indicates an expected call of Type
+// Type indicates an expected call of Type.
 func (mr *OutboundManagerMockRecorder) Type() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Type", reflect.TypeOf((*OutboundManager)(nil).Type))
 }
 
-// OutboundHandlerSelector is a mock of HandlerSelector interface
+// OutboundHandlerSelector is a mock of HandlerSelector interface.
 type OutboundHandlerSelector struct {
 	ctrl     *gomock.Controller
 	recorder *OutboundHandlerSelectorMockRecorder
 }
 
-// OutboundHandlerSelectorMockRecorder is the mock recorder for OutboundHandlerSelector
+// OutboundHandlerSelectorMockRecorder is the mock recorder for OutboundHandlerSelector.
 type OutboundHandlerSelectorMockRecorder struct {
 	mock *OutboundHandlerSelector
 }
 
-// NewOutboundHandlerSelector creates a new mock instance
+// NewOutboundHandlerSelector creates a new mock instance.
 func NewOutboundHandlerSelector(ctrl *gomock.Controller) *OutboundHandlerSelector {
 	mock := &OutboundHandlerSelector{ctrl: ctrl}
 	mock.recorder = &OutboundHandlerSelectorMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *OutboundHandlerSelector) EXPECT() *OutboundHandlerSelectorMockRecorder {
 	return m.recorder
 }
 
-// Select mocks base method
+// Select mocks base method.
 func (m *OutboundHandlerSelector) Select(arg0 []string) []string {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Select", arg0)
@@ -163,7 +164,7 @@ func (m *OutboundHandlerSelector) Select(arg0 []string) []string {
 	return ret0
 }
 
-// Select indicates an expected call of Select
+// Select indicates an expected call of Select.
 func (mr *OutboundHandlerSelectorMockRecorder) Select(arg0 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Select", reflect.TypeOf((*OutboundHandlerSelector)(nil).Select), arg0)

testing/mocks/proxy.go

@@ -6,38 +6,39 @@ package mocks
 
 import (
 	context "context"
+	reflect "reflect"
+
 	gomock "github.com/golang/mock/gomock"
 	net "github.com/xtls/xray-core/common/net"
 	routing "github.com/xtls/xray-core/features/routing"
 	transport "github.com/xtls/xray-core/transport"
 	internet "github.com/xtls/xray-core/transport/internet"
-	reflect "reflect"
 )
 
-// ProxyInbound is a mock of Inbound interface
+// ProxyInbound is a mock of Inbound interface.
 type ProxyInbound struct {
 	ctrl     *gomock.Controller
 	recorder *ProxyInboundMockRecorder
 }
 
-// ProxyInboundMockRecorder is the mock recorder for ProxyInbound
+// ProxyInboundMockRecorder is the mock recorder for ProxyInbound.
 type ProxyInboundMockRecorder struct {
 	mock *ProxyInbound
 }
 
-// NewProxyInbound creates a new mock instance
+// NewProxyInbound creates a new mock instance.
 func NewProxyInbound(ctrl *gomock.Controller) *ProxyInbound {
 	mock := &ProxyInbound{ctrl: ctrl}
 	mock.recorder = &ProxyInboundMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *ProxyInbound) EXPECT() *ProxyInboundMockRecorder {
 	return m.recorder
 }
 
-// Network mocks base method
+// Network mocks base method.
 func (m *ProxyInbound) Network() []net.Network {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Network")
@@ -45,13 +46,13 @@ func (m *ProxyInbound) Network() []net.Network {
 	return ret0
 }
 
-// Network indicates an expected call of Network
+// Network indicates an expected call of Network.
 func (mr *ProxyInboundMockRecorder) Network() *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Network", reflect.TypeOf((*ProxyInbound)(nil).Network))
 }
 
-// Process mocks base method
+// Process mocks base method.
 func (m *ProxyInbound) Process(arg0 context.Context, arg1 net.Network, arg2 internet.Connection, arg3 routing.Dispatcher) error {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Process", arg0, arg1, arg2, arg3)
@@ -59,36 +60,36 @@ func (m *ProxyInbound) Process(arg0 context.Context, arg1 net.Network, arg2 inte
 	return ret0
 }
 
-// Process indicates an expected call of Process
+// Process indicates an expected call of Process.
 func (mr *ProxyInboundMockRecorder) Process(arg0, arg1, arg2, arg3 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Process", reflect.TypeOf((*ProxyInbound)(nil).Process), arg0, arg1, arg2, arg3)
 }
 
-// ProxyOutbound is a mock of Outbound interface
+// ProxyOutbound is a mock of Outbound interface.
 type ProxyOutbound struct {
 	ctrl     *gomock.Controller
 	recorder *ProxyOutboundMockRecorder
 }
 
-// ProxyOutboundMockRecorder is the mock recorder for ProxyOutbound
+// ProxyOutboundMockRecorder is the mock recorder for ProxyOutbound.
 type ProxyOutboundMockRecorder struct {
 	mock *ProxyOutbound
 }
 
-// NewProxyOutbound creates a new mock instance
+// NewProxyOutbound creates a new mock instance.
 func NewProxyOutbound(ctrl *gomock.Controller) *ProxyOutbound {
 	mock := &ProxyOutbound{ctrl: ctrl}
 	mock.recorder = &ProxyOutboundMockRecorder{mock}
 	return mock
 }
 
-// EXPECT returns an object that allows the caller to indicate expected use
+// EXPECT returns an object that allows the caller to indicate expected use.
 func (m *ProxyOutbound) EXPECT() *ProxyOutboundMockRecorder {
 	return m.recorder
 }
 
-// Process mocks base method
+// Process mocks base method.
 func (m *ProxyOutbound) Process(arg0 context.Context, arg1 *transport.Link, arg2 internet.Dialer) error {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "Process", arg0, arg1, arg2)
@@ -96,7 +97,7 @@ func (m *ProxyOutbound) Process(arg0 context.Context, arg1 *transport.Link, arg2
 	return ret0
 }
 
-// Process indicates an expected call of Process
+// Process indicates an expected call of Process.
 func (mr *ProxyOutboundMockRecorder) Process(arg0, arg1, arg2 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Process", reflect.TypeOf((*ProxyOutbound)(nil).Process), arg0, arg1, arg2)

transport/internet/system_dialer.go

@@ -63,40 +63,23 @@ func (d *DefaultSystemDialer) lookupIP(domain string, strategy DomainStrategy, l
 		return nil, nil
 	}
 
-	var option = dns.IPOption{
-		IPv4Enable: true,
-		IPv6Enable: true,
-		FakeEnable: false,
-	}
-
+	var opt dns.Option
 	switch {
 	case strategy == DomainStrategy_USE_IP4 || (localAddr != nil && localAddr.Family().IsIPv4()):
-		option = dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: false,
-			FakeEnable: false,
-		}
+		opt = dns.LookupIPv4Only
 	case strategy == DomainStrategy_USE_IP6 || (localAddr != nil && localAddr.Family().IsIPv6()):
-		option = dns.IPOption{
-			IPv4Enable: false,
-			IPv6Enable: true,
-			FakeEnable: false,
-		}
+		opt = dns.LookupIPv6Only
 	case strategy == DomainStrategy_AS_IS:
 		return nil, nil
 	}
 
-	return d.dns.LookupIP(domain, option)
+	return d.dns.LookupOptions(domain, opt, dns.LookupNoFake)
 }
 
 func (d *DefaultSystemDialer) canLookupIP(ctx context.Context, dst net.Destination, sockopt *SocketConfig) bool {
 	if sockopt == nil || dst.Address.Family().IsIP() || d.dns == nil {
 		return false
 	}
-	if dst.Address.Domain() == LookupDomainFromContext(ctx) {
-		newError("infinite loop detected").AtError().WriteToLog(session.ExportIDToError(ctx))
-		return false
-	}
 	return sockopt.DomainStrategy != DomainStrategy_AS_IS
 }
 

transport/internet/system_dialer_context.go

@@ -1,18 +0,0 @@
-package internet
-
-import "context"
-
-type systemDialer int
-
-const systemDialerKey systemDialer = 0
-
-func ContextWithLookupDomain(ctx context.Context, domain string) context.Context {
-	return context.WithValue(ctx, systemDialerKey, domain)
-}
-
-func LookupDomainFromContext(ctx context.Context) string {
-	if domain, ok := ctx.Value(systemDialerKey).(string); ok {
-		return domain
-	}
-	return ""
-}