Add support for internal DNS system

app/dns/dns.go

@@ -210,6 +210,34 @@ func (s *DNS) LookupIP(domain string, option dns.IPOption) ([]net.IP, error) {
 	return nil, errors.New("returning nil for domain ", domain).Base(errors.Combine(errs...))
 }
 
+func (s *DNS) LookupHTTPS(domain string) (map[string]string, error) {
+	errs := []error{}
+	ctx := session.ContextWithInbound(s.ctx, &session.Inbound{Tag: s.tag})
+	for _, client := range s.sortClients(domain) {
+		if strings.EqualFold(client.Name(), "FakeDNS") {
+			errors.LogDebug(s.ctx, "skip DNS resolution for domain ", domain, " at server ", client.Name())
+			continue
+		}
+		EnhancedServer, ok := client.server.(EnhancedServer)
+		if !ok {
+			continue
+		}
+		HTTPSRecord, err := EnhancedServer.QueryHTTPS(ctx, domain, s.disableCache)
+		if len(HTTPSRecord) > 0 {
+			return HTTPSRecord, nil
+		}
+		if err != nil {
+			errors.LogInfoInner(s.ctx, err, "failed to lookup HTTPS for domain ", domain, " at server ", client.Name())
+			errs = append(errs, err)
+		}
+		// 5 for RcodeRefused in miekg/dns, hardcode to reduce binary size
+		if err != context.Canceled && err != context.DeadlineExceeded && err != errExpectedIPNonMatch && err != dns.ErrEmptyResponse && dns.RCodeFromError(err) != 5 {
+			return nil, err
+		}
+	}
+	return nil, errors.New("returning nil for domain ", domain).Base(errors.Combine(errs...))
+}
+
 // LookupHosts implements dns.HostsLookup.
 func (s *DNS) LookupHosts(domain string) *net.Address {
 	domain = strings.TrimSuffix(domain, ".")

app/dns/dnscommon.go

@@ -29,6 +29,12 @@ type record struct {
 	AAAA *IPRecord
 }
 
+type HTTPSRecord struct {
+	keypair map[string]string
+	Expire time.Time
+	RCode  dnsmessage.RCode
+}
+
 // IPRecord is a cacheable item for a resolved domain
 type IPRecord struct {
 	ReqID  uint16

app/dns/nameserver.go

@@ -23,6 +23,13 @@ type Server interface {
 	QueryIP(ctx context.Context, domain string, clientIP net.IP, option dns.IPOption, disableCache bool) ([]net.IP, error)
 }
 
+// Server is the interface for Enhanced Name Server.
+type EnhancedServer interface {
+	Server
+	// QueryHTTPS sends HTTPS queries to its configured server.
+	QueryHTTPS(ctx context.Context, domain string, disableCache bool) (map[string]string, error)
+}
+
 // Client is the interface for DNS client.
 type Client struct {
 	server       Server

app/dns/nameserver_doh.go

@@ -12,6 +12,7 @@ import (
 	"sync"
 	"time"
 
+	mdns "github.com/miekg/dns"
 	utls "github.com/refraction-networking/utls"
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/crypto"
@@ -42,6 +43,8 @@ type DoHNameServer struct {
 	dohURL        string
 	name          string
 	queryStrategy QueryStrategy
+
+	HTTPSCache map[string]*HTTPSRecord
 }
 
 // NewDoHNameServer creates DOH/DOHL client object for remote/local resolving.
@@ -58,6 +61,7 @@ func NewDoHNameServer(url *url.URL, queryStrategy QueryStrategy, dispatcher rout
 		name:          mode + "//" + url.Host,
 		dohURL:        url.String(),
 		queryStrategy: queryStrategy,
+		HTTPSCache:    make(map[string]*HTTPSRecord),
 	}
 	s.cleanup = &task.Periodic{
 		Interval: time.Minute,
@@ -207,6 +211,21 @@ func (s *DoHNameServer) updateIP(req *dnsRequest, ipRec *IPRecord) {
 	common.Must(s.cleanup.Start())
 }
 
+func (s *DoHNameServer) updateHTTPS(domain string, HTTPSRec *HTTPSRecord) {
+	s.Lock()
+	rec, found := s.HTTPSCache[domain]
+	if !found {
+		s.HTTPSCache[domain] = HTTPSRec
+	}
+	if found && rec.Expire.Before(time.Now()) {
+		s.HTTPSCache[domain] = HTTPSRec
+	}
+	errors.LogInfo(context.Background(), s.name, " got answer: ", domain, " ", "HTTPS", " -> ", HTTPSRec.keypair)
+
+	s.pub.Publish(domain+"HTTPS", nil)
+	s.Unlock()
+}
+
 func (s *DoHNameServer) newReqID() uint16 {
 	return 0
 }
@@ -271,6 +290,59 @@ func (s *DoHNameServer) sendQuery(ctx context.Context, domain string, clientIP n
 	}
 }
 
+func (s *DoHNameServer) sendHTTPSQuery(ctx context.Context, domain string) {
+	errors.LogInfo(ctx, s.name, " querying HTTPS record for: ", domain)
+	var deadline time.Time
+	if d, ok := ctx.Deadline(); ok {
+		deadline = d
+	} else {
+		deadline = time.Now().Add(time.Second * 5)
+	}
+	dnsCtx := ctx
+	// 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:       "https",
+		SkipDNSResolve: true,
+	})
+	var cancel context.CancelFunc
+	dnsCtx, cancel = context.WithDeadline(dnsCtx, deadline)
+	defer cancel()
+
+	m := new(mdns.Msg)
+	m.SetQuestion(mdns.Fqdn(domain), mdns.TypeHTTPS)
+	m.Id = 0
+	msg, _ := m.Pack()
+	response, err := s.dohHTTPSContext(dnsCtx, msg)
+	if err != nil {
+		errors.LogError(ctx, err, "failed to retrieve HTTPS query response for ", domain)
+		return
+	}
+	respMsg := new(mdns.Msg)
+	err = respMsg.Unpack(response)
+	if err != nil {
+		errors.LogError(ctx, err, "failed to parse HTTPS query response for ", domain)
+		return
+	}
+	var Record = HTTPSRecord{
+		keypair: map[string]string{},
+	}
+	if len(respMsg.Answer) > 0 {
+		for _, answer := range respMsg.Answer {
+			if https, ok := answer.(*mdns.HTTPS); ok && https.Hdr.Name == mdns.Fqdn(domain) {
+				for _, value := range https.Value {
+					Record.keypair[value.Key().String()] = value.String()
+				}
+			}
+		}
+	}
+	Record.Expire = time.Now().Add(time.Duration(respMsg.Answer[0].Header().Ttl) * time.Second)
+
+	s.updateHTTPS(domain, &Record)
+}
+
 func (s *DoHNameServer) dohHTTPSContext(ctx context.Context, b []byte) ([]byte, error) {
 	body := bytes.NewBuffer(b)
 	req, err := http.NewRequest("POST", s.dohURL, body)
@@ -341,6 +413,27 @@ func (s *DoHNameServer) findIPsForDomain(domain string, option dns_feature.IPOpt
 	return nil, errRecordNotFound
 }
 
+func (s *DoHNameServer) findRecordsForDomain(domain string, Querytype string) (any, error) {
+	switch Querytype {
+	case "HTTPS":
+		s.RLock()
+		record, found := s.HTTPSCache[domain]
+		s.RUnlock()
+		if !found {
+			return nil, errRecordNotFound
+		}
+		if len(record.keypair) == 0 {
+			return nil, dns_feature.ErrEmptyResponse
+		}
+		if record.Expire.Before(time.Now()) {
+			return nil, errRecordNotFound
+		}
+		return record, nil
+	default:
+		return nil, errors.New("unsupported query type: " + Querytype)
+	}
+}
+
 // QueryIP implements Server.
 func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, clientIP net.IP, option dns_feature.IPOption, disableCache bool) ([]net.IP, error) { // nolint: dupl
 	fqdn := Fqdn(domain)
@@ -403,3 +496,44 @@ func (s *DoHNameServer) QueryIP(ctx context.Context, domain string, clientIP net
 		}
 	}
 }
+
+// QueryHTTPS implements EnhancedServer.
+func (s *DoHNameServer) QueryHTTPS(ctx context.Context, domain string, disableCache bool) (map[string]string, error) { // nolint: dupl
+	fqdn := Fqdn(domain)
+
+	if disableCache {
+		errors.LogDebug(ctx, "DNS cache is disabled. Querying HTTPS for ", domain, " at ", s.name)
+	} else {
+		Record, err := s.findRecordsForDomain(fqdn, "HTTPS")
+		if err == nil || err == dns_feature.ErrEmptyResponse {
+			errors.LogDebugInner(ctx, err, s.name, " cache HIT ", domain, " -> ", Record.(HTTPSRecord).keypair)
+			return Record.(HTTPSRecord).keypair, err
+		}
+	}
+	sub := s.pub.Subscribe(fqdn + "HTTPS")
+	defer sub.Close()
+	done := make(chan interface{})
+	go func() {
+		if sub != nil {
+			select {
+			case <-sub.Wait():
+			case <-ctx.Done():
+			}
+		}
+		close(done)
+	}()
+	s.sendHTTPSQuery(ctx, fqdn)
+
+	for {
+		Record, err := s.findRecordsForDomain(fqdn, "HTTPS")
+		if err != errRecordNotFound {
+			return Record.(*HTTPSRecord).keypair, err
+		}
+
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case <-done:
+		}
+	}
+}

features/dns/client.go

@@ -24,6 +24,13 @@ type Client interface {
 	LookupIP(domain string, option IPOption) ([]net.IP, error)
 }
 
+type EnhancedClient interface {
+	Client
+
+	// LookupHTTPS returns HTTPS records for the given domain.
+	LookupHTTPS(domain string) (map[string]string, error)
+}
+
 type HostsLookup interface {
 	LookupHosts(domain string) *net.Address
 }

go.mod

@@ -3,7 +3,7 @@ module github.com/xtls/xray-core
 go 1.24
 
 require (
-	github.com/OmarTariq612/goech v0.0.0-20240405204721-8e2e1dafd3a0
+	github.com/OmarTariq612/goech v0.0.1
 	github.com/cloudflare/circl v1.6.0
 	github.com/ghodss/yaml v1.0.1-0.20220118164431-d8423dcdf344
 	github.com/golang/mock v1.7.0-rc.1

go.sum

@@ -1,5 +1,5 @@
-github.com/OmarTariq612/goech v0.0.0-20240405204721-8e2e1dafd3a0 h1:Wo41lDOevRJSGpevP+8Pk5bANX7fJacO2w04aqLiC5I=
+github.com/OmarTariq612/goech v0.0.1 h1:/0c918Bk1ik65GXDj2k7SOK78DyZr30Jmq9euy1/HXg=
-github.com/OmarTariq612/goech v0.0.0-20240405204721-8e2e1dafd3a0/go.mod h1:FVGavL/QEBQDcBpr3fAojoK17xX5k9bicBphrOpP7uM=
+github.com/OmarTariq612/goech v0.0.1/go.mod h1:FVGavL/QEBQDcBpr3fAojoK17xX5k9bicBphrOpP7uM=
 github.com/andybalholm/brotli v1.1.0 h1:eLKJA0d02Lf0mVpIDgYnqXcUn0GqVmEFny3VuID1U3M=
 github.com/andybalholm/brotli v1.1.0/go.mod h1:sms7XGricyQI9K10gOSf56VKKWS4oLer58Q+mhRPtnY=
 github.com/cloudflare/circl v1.6.0 h1:cr5JKic4HI+LkINy2lg3W2jF8sHCVTBncJr5gIIq7qk=

infra/conf/transport_internet.go

@@ -412,6 +412,8 @@ type TLSConfig struct {
 	MasterKeyLog                         string           `json:"masterKeyLog"`
 	ServerNameToVerify                   string           `json:"serverNameToVerify"`
 	VerifyPeerCertInNames                []string         `json:"verifyPeerCertInNames"`
+	ECHConfigList                        string           `json:"echConfigList"`
+	EchKeySets                           string           `json:"echKeySets"`
 }
 
 // Build implements Buildable.
@@ -483,6 +485,16 @@ func (c *TLSConfig) Build() (proto.Message, error) {
 	}
 	config.VerifyPeerCertInNames = c.VerifyPeerCertInNames
 
+	config.EchConfigList = c.ECHConfigList
+
+	if c.EchKeySets != "" {
+		EchPrivateKey, err := base64.StdEncoding.DecodeString(c.EchKeySets)
+		if err != nil {
+			return nil, errors.New("invalid ECH Config", c.EchKeySets)
+		}
+		config.EchKeySets = EchPrivateKey
+	}
+
 	return config, nil
 }
 

main/commands/all/tls/ech.go

@@ -1,10 +1,8 @@
 package tls
 
 import (
-	"encoding/json"
 	"encoding/pem"
 	"os"
-	"strings"
 
 	"github.com/OmarTariq612/goech"
 	"github.com/cloudflare/circl/hpke"
@@ -13,13 +11,13 @@ import (
 )
 
 var cmdECH = &base.Command{
-	UsageLine: `{{.Exec}} tls ech [--serverName (string)] [--json]`,
+	UsageLine: `{{.Exec}} tls ech [--serverName (string)] [--pem]`,
 	Short:     `Generate TLS-ECH certificates`,
 	Long: `
 Generate TLS-ECH certificates.
 
 Set serverName to your custom string: {{.Exec}} tls ech --serverName (string)
-Generate into json format: {{.Exec}} tls ech --json
+Generate into pem format: {{.Exec}} tls ech --pem
 `, // Enable PQ signature schemes: {{.Exec}} tls ech --pq-signature-schemes-enabled
 }
 
@@ -29,7 +27,7 @@ func init() {
 
 var input_pqSignatureSchemesEnabled = cmdECH.Flag.Bool("pqSignatureSchemesEnabled", false, "")
 var input_serverName = cmdECH.Flag.String("serverName", "cloudflare-ech.com", "")
-var input_json = cmdECH.Flag.Bool("json", false, "True == turn on json output")
+var input_pem = cmdECH.Flag.Bool("pem", false, "True == turn on pem output")
 
 func executeECH(cmd *base.Command, args []string) {
 	var kem hpke.KEM
@@ -40,30 +38,26 @@ func executeECH(cmd *base.Command, args []string) {
 		kem = hpke.KEM_X25519_HKDF_SHA256
 	}
 
-	echKeySet, err := goech.GenerateECHKeySet(0, *input_serverName, kem)
+	echKeySet, err := goech.GenerateECHKeySet(0, *input_serverName, kem, nil)
 	common.Must(err)
 
-	configBuffer, _ := echKeySet.ECHConfig.MarshalBinary()
+	// Make single key set to a list with only one element
-	keyBuffer, _ := echKeySet.MarshalBinary()
+	ECHConfigList := make(goech.ECHConfigList, 1)
+	ECHConfigList[0] = echKeySet.ECHConfig
+	ECHKeySetList := make(goech.ECHKeySetList, 1)
+	ECHKeySetList[0] = echKeySet
+	configBuffer, _ := ECHConfigList.MarshalBinary()
+	keyBuffer, _ := ECHKeySetList.MarshalBinary()
+	configStr, _ := ECHConfigList.ToBase64()
+	keySetStr, _ := ECHKeySetList.ToBase64()
 
 	configPEM := string(pem.EncodeToMemory(&pem.Block{Type: "ECH CONFIGS", Bytes: configBuffer}))
 	keyPEM := string(pem.EncodeToMemory(&pem.Block{Type: "ECH KEYS", Bytes: keyBuffer}))
-	if *input_json {
+	if *input_pem {
-		jECHConfigs := map[string]interface{}{
-			"configs": strings.Split(strings.TrimSpace(string(configPEM)), "\n"),
-		}
-		jECHKey := map[string]interface{}{
-			"key": strings.Split(strings.TrimSpace(string(keyPEM)), "\n"),
-		}
-
-		for _, i := range []map[string]interface{}{jECHConfigs, jECHKey} {
-			content, err := json.MarshalIndent(i, "", "  ")
-			common.Must(err)
-			os.Stdout.Write(content)
-			os.Stdout.WriteString("\n")
-		}
-	} else {
 		os.Stdout.WriteString(configPEM)
 		os.Stdout.WriteString(keyPEM)
+	} else {
+		os.Stdout.WriteString("ECH config list: \n" + configStr + "\n")
+		os.Stdout.WriteString("ECH Key sets: \n" + keySetStr + "\n")
 	}
 }

transport/internet/dialer.go

@@ -106,6 +106,14 @@ func lookupIP(domain string, strategy DomainStrategy, localAddr net.Address) ([]
 	return ips, err
 }
 
+func LookupHTTPS(domain string) (map[string]string, error) {
+	if dnsClient == nil {
+		return nil, nil
+	}
+	HTTPSRecord, err := dnsClient.(dns.EnhancedClient).LookupHTTPS(domain)
+	return HTTPSRecord, err
+}
+
 func canLookupIP(ctx context.Context, dst net.Destination, sockopt *SocketConfig) bool {
 	if dst.Address.Family().IsIP() || dnsClient == nil {
 		return false

transport/internet/tls/config.go

@@ -444,6 +444,12 @@ func (c *Config) GetTLSConfig(opts ...Option) *tls.Config {
 			config.KeyLogWriter = writer
 		}
 	}
+	if len(c.EchConfigList) > 0 || len(c.EchKeySets) > 0 {
+		err := ApplyECH(c, config)
+		if err != nil {
+			errors.LogError(context.Background(), err)
+		}
+	}
 
 	return config
 }

transport/internet/tls/config.pb.go

@@ -217,6 +217,8 @@ type Config struct {
 	// @Document After allow_insecure (automatically), if the server's cert can't be verified by any of these names, pinned_peer_certificate_chain_sha256 will be tried.
 	// @Critical
 	VerifyPeerCertInNames []string `protobuf:"bytes,17,rep,name=verify_peer_cert_in_names,json=verifyPeerCertInNames,proto3" json:"verify_peer_cert_in_names,omitempty"`
+	EchConfigList         string   `protobuf:"bytes,18,opt,name=ech_config_list,json=echConfigList,proto3" json:"ech_config_list,omitempty"`
+	EchKeySets            []byte   `protobuf:"bytes,19,opt,name=ech_key_sets,json=echKeySets,proto3" json:"ech_key_sets,omitempty"`
 }
 
 func (x *Config) Reset() {
@@ -361,6 +363,20 @@ func (x *Config) GetVerifyPeerCertInNames() []string {
 	return nil
 }
 
+func (x *Config) GetEchConfigList() string {
+	if x != nil {
+		return x.EchConfigList
+	}
+	return ""
+}
+
+func (x *Config) GetEchKeySets() []byte {
+	if x != nil {
+		return x.EchKeySets
+	}
+	return nil
+}
+
 var File_transport_internet_tls_config_proto protoreflect.FileDescriptor
 
 var file_transport_internet_tls_config_proto_rawDesc = []byte{
@@ -392,7 +408,7 @@ var file_transport_internet_tls_config_proto_rawDesc = []byte{
 	0x4e, 0x43, 0x49, 0x50, 0x48, 0x45, 0x52, 0x4d, 0x45, 0x4e, 0x54, 0x10, 0x00, 0x12, 0x14, 0x0a,
 	0x10, 0x41, 0x55, 0x54, 0x48, 0x4f, 0x52, 0x49, 0x54, 0x59, 0x5f, 0x56, 0x45, 0x52, 0x49, 0x46,
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+	0x5f, 0x49, 0x53, 0x53, 0x55, 0x45, 0x10, 0x02, 0x22, 0xe4, 0x06, 0x0a, 0x06, 0x43, 0x6f, 0x6e,
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@@ -442,15 +458,19 @@ var file_transport_internet_tls_config_proto_rawDesc = []byte{
 	0x65, 0x72, 0x69, 0x66, 0x79, 0x5f, 0x70, 0x65, 0x65, 0x72, 0x5f, 0x63, 0x65, 0x72, 0x74, 0x5f,
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+	0x73, 0x70, 0x6f, 0x72, 0x74, 0x2e, 0x69, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x2e, 0x74,
-	0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x2e, 0x54, 0x6c, 0x73, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74,
+	0x6c, 0x73, 0x50, 0x01, 0x5a, 0x30, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f, 0x6d,
-	0x6f, 0x33,
+	0x2f, 0x78, 0x74, 0x6c, 0x73, 0x2f, 0x78, 0x72, 0x61, 0x79, 0x2d, 0x63, 0x6f, 0x72, 0x65, 0x2f,
+	0x74, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2f, 0x69, 0x6e, 0x74, 0x65, 0x72, 0x6e,
+	0x65, 0x74, 0x2f, 0x74, 0x6c, 0x73, 0xaa, 0x02, 0x1b, 0x58, 0x72, 0x61, 0x79, 0x2e, 0x54, 0x72,
+	0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2e, 0x49, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74,
+	0x2e, 0x54, 0x6c, 0x73, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
 }
 
 var (

transport/internet/tls/config.proto

@@ -91,4 +91,8 @@ message Config {
      @Critical
   */
   repeated string verify_peer_cert_in_names = 17;
+
+  string ech_config_list = 18;
+
+  bytes ech_key_sets = 19;
 }

transport/internet/tls/ech.go

@@ -0,0 +1,255 @@
+package tls
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"io"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/OmarTariq612/goech"
+	"github.com/miekg/dns"
+	"github.com/xtls/xray-core/common/errors"
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/transport/internet"
+)
+
+func ApplyECH(c *Config, config *tls.Config) error {
+	var ECHConfig []byte
+	var err error
+
+	nameToQuery := c.ServerName
+	var DNSServer string
+
+	// for client
+	if len(c.EchConfigList) != 0 {
+		// direct base64 config
+		if strings.HasPrefix(c.EchConfigList, "base64") {
+			Base64ECHConfigList := c.EchConfigList[len("base64://"):]
+			ECHConfigList, err := goech.ECHConfigListFromBase64(Base64ECHConfigList)
+			if err != nil {
+				return errors.New("Failed to unmarshal ECHConfigList: ", err)
+			}
+			ECHConfig, _ = ECHConfigList.MarshalBinary()
+		} else { // query config from dns
+			parts := strings.Split(c.EchConfigList, "+")
+			if len(parts) == 2 {
+				// parse ECH DNS server in format of "example.com+https://1.1.1.1/dns-query"
+				nameToQuery = parts[0]
+				DNSServer = parts[1]
+			} else if len(parts) == 1 {
+				// normal format
+				DNSServer = parts[0]
+			} else {
+				return errors.New("Invalid ECH DNS server format: ", c.EchConfigList)
+			}
+			if nameToQuery == "" {
+				return errors.New("Using DNS for ECH Config needs serverName or use Server format example.com+https://1.1.1.1/dns-query")
+			}
+			ECHConfig, err = QueryRecord(nameToQuery, DNSServer)
+			if err != nil {
+				return err
+			}
+		}
+
+		config.EncryptedClientHelloConfigList = ECHConfig
+	}
+
+	// for server
+	if len(c.EchKeySets) != 0 {
+		var keys []tls.EncryptedClientHelloKey
+		KeySets, err := goech.UnmarshalECHKeySetList(c.EchKeySets)
+		if err != nil {
+			return errors.New("Failed to unmarshal ECHKeySetList: ", err)
+		}
+		for idx, keySet := range KeySets {
+			ECHConfig, err := keySet.ECHConfig.MarshalBinary()
+			ECHPrivateKey, err := keySet.PrivateKey.MarshalBinary()
+			if err != nil {
+				return errors.New("Failed to marshal ECHKey in index: ", idx, "with err: ", err)
+			}
+			keys = append(keys, tls.EncryptedClientHelloKey{
+				Config:     ECHConfig,
+				PrivateKey: ECHPrivateKey})
+		}
+		config.EncryptedClientHelloKeys = keys
+	}
+	
+	return nil
+}
+
+type record struct {
+	echConfig []byte
+	expire    time.Time
+}
+
+var (
+	dnsCache sync.Map
+	// global Lock? I'm not sure if this needs finer grained locks.
+	// If we do this, we will need to nest another layer of struct
+	updating sync.Mutex
+)
+
+// QueryRecord returns the ECH config for given domain.
+// If the record is not in cache or expired, it will query the DNS server and update the cache.
+func QueryRecord(domain string, server string) ([]byte, error) {
+	val, found := dnsCache.Load(domain)
+	rec, _ := val.(record)
+	if found && rec.expire.After(time.Now()) {
+		errors.LogDebug(context.Background(), "Cache hit for domain: ", domain)
+		return rec.echConfig, nil
+	}
+
+	updating.Lock()
+	defer updating.Unlock()
+	// Try to get cache again after lock, in case another goroutine has updated it
+	// This might happen when the core tring is just stared and multiple goroutines are trying to query the same domain
+	val, found = dnsCache.Load(domain)
+	rec, _ = val.(record)
+	if found && rec.expire.After(time.Now()) {
+		errors.LogDebug(context.Background(), "ECH Config cache hit for domain: ", domain, " after trying to get update lock")
+		return rec.echConfig, nil
+	}
+
+	// Query ECH config from DNS server
+	errors.LogDebug(context.Background(), "Trying to query ECH config for domain: ", domain, " with ECH server: ", server)
+	echConfig, ttl, err := dnsQuery(server, domain)
+	if err != nil {
+		return []byte{}, err
+	}
+
+	// Set minimum TTL to 600 seconds
+	if ttl < 600 {
+		ttl = 600
+	}
+
+	// Update cache
+	newRecored := record{
+		echConfig: echConfig,
+		expire:    time.Now().Add(time.Second * time.Duration(ttl)),
+	}
+	dnsCache.Store(domain, newRecored)
+	return echConfig, nil
+}
+
+// dnsQuery is the real func for sending type65 query for given domain to given DNS server.
+// return ECH config, TTL and error
+func dnsQuery(server string, domain string) ([]byte, uint32, error) {
+	if server == "xray" {
+		HTTPSRecord, err := internet.LookupHTTPS(domain)
+		if err !=nil {
+			return []byte{}, 0, errors.New("failed to lookup HTTPS record with xray internal DNS: ", err)
+		}
+		ECH := HTTPSRecord["ech"]
+		if ECH == "" {
+			return []byte{}, 0, errors.New("no ech record found")
+		}
+		Base64echConfigList, err := goech.ECHConfigListFromBase64(ECH)
+		if err != nil {
+			return []byte{}, 0, errors.New("failed to unmarshal ECHConfigList: ", err)
+		}
+		echConfigList, _ := Base64echConfigList.MarshalBinary()
+		return echConfigList, 600, nil
+	}
+	m := new(dns.Msg)
+	var dnsResolve []byte
+	m.SetQuestion(dns.Fqdn(domain), dns.TypeHTTPS)
+	// for DOH server
+	if strings.HasPrefix(server, "https://") {
+		// always 0 in DOH
+		m.Id = 0
+		msg, err := m.Pack()
+		if err != nil {
+			return []byte{}, 0, err
+		}
+		// All traffic sent by core should via xray's internet.DialSystem
+		// This involves the behavior of some Android VPN GUI clients
+		tr := &http.Transport{
+			IdleConnTimeout:   90 * time.Second,
+			ForceAttemptHTTP2: true,
+			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+				dest, err := net.ParseDestination(network + ":" + addr)
+				if err != nil {
+					return nil, err
+				}
+				conn, err := internet.DialSystem(ctx, dest, nil)
+				if err != nil {
+					return nil, err
+				}
+				return conn, nil
+			},
+		}
+		client := &http.Client{
+			Timeout:   5 * time.Second,
+			Transport: tr,
+		}
+		req, err := http.NewRequest("POST", server, bytes.NewReader(msg))
+		if err != nil {
+			return []byte{}, 0, err
+		}
+		req.Header.Set("Content-Type", "application/dns-message")
+		resp, err := client.Do(req)
+		if err != nil {
+			return []byte{}, 0, err
+		}
+		defer resp.Body.Close()
+		respBody, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return []byte{}, 0, err
+		}
+		if resp.StatusCode != http.StatusOK {
+			return []byte{}, 0, errors.New("query failed with response code:", resp.StatusCode)
+		}
+		dnsResolve = respBody
+	} else if strings.HasPrefix(server, "udp://") { // for classic udp dns server
+		udpServerAddr := server[len("udp://"):]
+		// default port 53 if not specified
+		if !strings.Contains(udpServerAddr, ":") {
+			udpServerAddr = udpServerAddr + ":53"
+		}
+		dest, err := net.ParseDestination("udp" + ":" + udpServerAddr)
+		if err != nil {
+			return nil, 0, errors.New("failed to parse udp dns server ", udpServerAddr, " for ECH: ", err)
+		}
+		dnsTimeoutCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		// use xray's internet.DialSystem as mentioned above
+		conn, err := internet.DialSystem(dnsTimeoutCtx, dest, nil)
+		defer conn.Close()
+		if err != nil {
+			return []byte{}, 0, err
+		}
+		msg, err := m.Pack()
+		if err != nil {
+			return []byte{}, 0, err
+		}
+		conn.Write(msg)
+		udpResponse := make([]byte, 512)
+		_, err = conn.Read(udpResponse)
+		if err != nil {
+			return []byte{}, 0, err
+		}
+		dnsResolve = udpResponse
+	}
+	respMsg := new(dns.Msg)
+	err := respMsg.Unpack(dnsResolve)
+	if err != nil {
+		return []byte{}, 0, errors.New("failed to unpack dns response for ECH: ", err)
+	}
+	if len(respMsg.Answer) > 0 {
+		for _, answer := range respMsg.Answer {
+			if https, ok := answer.(*dns.HTTPS); ok && https.Hdr.Name == dns.Fqdn(domain) {
+				for _, v := range https.Value {
+					if echConfig, ok := v.(*dns.SVCBECHConfig); ok {
+						errors.LogDebug(context.Background(), "Get ECH config:", echConfig.String(), " TTL:", respMsg.Answer[0].Header().Ttl)
+						return echConfig.ECH, answer.Header().Ttl, nil
+					}
+				}
+			}
+		}
+	}
+	return []byte{}, 0, errors.New("no ech record found")
+}