ECH: client support TLS Encrypted Client Hello

infra/conf/transport_internet.go

@@ -389,6 +389,8 @@ type TLSConfig struct {
 	PinnedPeerCertificateChainSha256     *[]string        `json:"pinnedPeerCertificateChainSha256"`
 	PinnedPeerCertificatePublicKeySha256 *[]string        `json:"pinnedPeerCertificatePublicKeySha256"`
 	MasterKeyLog                         string           `json:"masterKeyLog"`
+	ECHConfig                            string           `json:"echConfig"`
+	ECHDOHServer                         string           `json:"echDohServer"`
 }
 
 // Build implements Buildable.
@@ -443,7 +445,16 @@ func (c *TLSConfig) Build() (proto.Message, error) {
 		}
 	}
 
+	if c.ECHConfig != "" {
+		ECHConfig, err := base64.StdEncoding.DecodeString(c.ECHConfig)
+		if err != nil {
+			return nil, errors.New("invalid ECH Config", c.ECHConfig)
+		}
+		config.EchConfig = ECHConfig
+	}
+
 	config.MasterKeyLog = c.MasterKeyLog
+	config.Ech_DOHserver = c.ECHDOHServer
 
 	return config, nil
 }
@@ -757,19 +768,19 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 }
 
 type StreamConfig struct {
-	Network             *TransportProtocol  `json:"network"`
-	Security            string              `json:"security"`
-	TLSSettings         *TLSConfig          `json:"tlsSettings"`
-	REALITYSettings     *REALITYConfig      `json:"realitySettings"`
-	TCPSettings         *TCPConfig          `json:"tcpSettings"`
-	KCPSettings         *KCPConfig          `json:"kcpSettings"`
-	WSSettings          *WebSocketConfig    `json:"wsSettings"`
-	HTTPSettings        *HTTPConfig         `json:"httpSettings"`
-	SocketSettings      *SocketConfig       `json:"sockopt"`
-	GRPCConfig          *GRPCConfig         `json:"grpcSettings"`
-	GUNConfig           *GRPCConfig         `json:"gunSettings"`
-	HTTPUPGRADESettings *HttpUpgradeConfig  `json:"httpupgradeSettings"`
-	SplitHTTPSettings   *SplitHTTPConfig    `json:"splithttpSettings"`
+	Network             *TransportProtocol `json:"network"`
+	Security            string             `json:"security"`
+	TLSSettings         *TLSConfig         `json:"tlsSettings"`
+	REALITYSettings     *REALITYConfig     `json:"realitySettings"`
+	TCPSettings         *TCPConfig         `json:"tcpSettings"`
+	KCPSettings         *KCPConfig         `json:"kcpSettings"`
+	WSSettings          *WebSocketConfig   `json:"wsSettings"`
+	HTTPSettings        *HTTPConfig        `json:"httpSettings"`
+	SocketSettings      *SocketConfig      `json:"sockopt"`
+	GRPCConfig          *GRPCConfig        `json:"grpcSettings"`
+	GUNConfig           *GRPCConfig        `json:"gunSettings"`
+	HTTPUPGRADESettings *HttpUpgradeConfig `json:"httpupgradeSettings"`
+	SplitHTTPSettings   *SplitHTTPConfig   `json:"splithttpSettings"`
 }
 
 // Build implements Buildable.

transport/internet/tls/config.go

@@ -1,6 +1,7 @@
 package tls
 
 import (
+	"bytes"
 	"context"
 	"crypto/hmac"
 	"crypto/tls"
@@ -10,7 +11,6 @@ import (
 	"strings"
 	"sync"
 	"time"
-	"bytes"
 
 	"github.com/xtls/xray-core/common/errors"
 	"github.com/xtls/xray-core/common/net"
@@ -70,7 +70,7 @@ func (c *Config) BuildCertificates() []*tls.Certificate {
 			continue
 		}
 		index := len(certs) - 1
-		setupOcspTicker(entry, func(isReloaded, isOcspstapling bool){
+		setupOcspTicker(entry, func(isReloaded, isOcspstapling bool) {
 			cert := certs[index]
 			if isReloaded {
 				if newKeyPair := getX509KeyPair(); newKeyPair != nil {
@@ -162,7 +162,7 @@ func (c *Config) getCustomCA() []*Certificate {
 	for _, certificate := range c.Certificate {
 		if certificate.Usage == Certificate_AUTHORITY_ISSUE {
 			certs = append(certs, certificate)
-			setupOcspTicker(certificate, func(isReloaded, isOcspstapling bool){ })
+			setupOcspTicker(certificate, func(isReloaded, isOcspstapling bool) {})
 		}
 	}
 	return certs
@@ -390,6 +390,12 @@ func (c *Config) GetTLSConfig(opts ...Option) *tls.Config {
 			config.KeyLogWriter = writer
 		}
 	}
+	if len(c.EchConfig) > 0 || len(c.Ech_DOHserver) > 0 {
+		err := ApplyECH(c, config)
+		if err != nil {
+			errors.LogError(context.Background(), err)
+		}
+	}
 
 	return config
 }

transport/internet/tls/config.proto

@@ -88,4 +88,6 @@ message Config {
   repeated bytes pinned_peer_certificate_public_key_sha256 = 14;
 
   string master_key_log = 15;
+  bytes ech_config = 16;
+  string ech_DOHserver = 17;
 }

transport/internet/tls/ech.go

@@ -0,0 +1,140 @@
+//go:build go1.23
+// +build go1.23
+
+package tls
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"io"
+	"net/http"
+	"sync"
+	"time"
+
+	"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
+
+	if len(c.EchConfig) > 0 {
+		ECHConfig = c.EchConfig
+	} else { // ECH config > DOH lookup
+		if config.ServerName == "" {
+			return errors.New("Using DOH for ECH needs serverName")
+		}
+		ECHConfig, err = QueryRecord(c.ServerName, c.Ech_DOHserver)
+		if err != nil {
+			return err
+		}
+	}
+
+	config.EncryptedClientHelloConfigList = ECHConfig
+	return nil
+}
+
+type record struct {
+	record []byte
+	expire time.Time
+}
+
+var (
+	dnsCache = make(map[string]record)
+	mutex    sync.RWMutex
+)
+
+func QueryRecord(domain string, server string) ([]byte, error) {
+    mutex.Lock()
+    rec, found := dnsCache[domain]
+    if found && rec.expire.After(time.Now()) {
+        mutex.Unlock()
+        return rec.record, nil
+    }
+    mutex.Unlock()
+
+    errors.LogDebug(context.Background(), "Trying to query ECH config for domain: ", domain, " with ECH server: ", server)
+    record, ttl, err := dohQuery(server, domain)
+    if err != nil {
+        return []byte{}, err
+    }
+
+    if ttl < 600 {
+        ttl = 600
+    }
+
+    mutex.Lock()
+    defer mutex.Unlock()
+    rec.record = record
+    rec.expire = time.Now().Add(time.Second * time.Duration(ttl))
+    dnsCache[domain] = rec
+    return record, nil
+}
+
+func dohQuery(server string, domain string) ([]byte, uint32, error) {
+	m := new(dns.Msg)
+	m.SetQuestion(dns.Fqdn(domain), dns.TypeHTTPS)
+	m.Id = 0
+	msg, err := m.Pack()
+	if err != nil {
+		return []byte{}, 0, err
+	}
+	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)
+	}
+	respMsg := new(dns.Msg)
+	err = respMsg.Unpack(respBody)
+	if err != nil {
+		return []byte{}, 0, 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")
+}

transport/internet/tls/ech_go121.go

@@ -0,0 +1,14 @@
+//go:build !go1.23
+// +build !go1.23
+
+package tls
+
+import (
+	"crypto/tls"
+
+	"github.com/xtls/xray-core/common/errors"
+)
+
+func ApplyECH(c *Config, config *tls.Config) error {
+	return errors.New("Win7 does not support ECH")
+}