Xray-core: Dynamic Chrome User-Agent for all HTTP requests by default (overwriteable through config) (#5658)

https://github.com/XTLS/Xray-core/issues/4996#issuecomment-3855274627
https://github.com/XTLS/Xray-core/pull/5658#issuecomment-3857332687

---------

Co-authored-by: RPRX <63339210+RPRX@users.noreply.github.com>
Co-authored-by: Fangliding <63339210+Fangliding@users.noreply.github.com>

transport/internet/grpc/dial.go

@@ -10,6 +10,7 @@ import (
 	"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/utils"
 	"github.com/xtls/xray-core/transport/internet"
 	"github.com/xtls/xray-core/transport/internet/grpc/encoding"
 	"github.com/xtls/xray-core/transport/internet/reality"
@@ -167,9 +168,11 @@ func getGrpcClient(ctx context.Context, dest net.Destination, streamSettings *in
 		dialOptions = append(dialOptions, grpc.WithInitialWindowSize(grpcSettings.InitialWindowsSize))
 	}
 
-	if grpcSettings.UserAgent != "" {
-		dialOptions = append(dialOptions, grpc.WithUserAgent(grpcSettings.UserAgent))
+	userAgent := grpcSettings.UserAgent
+	if userAgent == "" {
+		userAgent = utils.ChromeUA
 	}
+	dialOptions = append(dialOptions, grpc.WithUserAgent(userAgent))
 
 	var grpcDestHost string
 	if dest.Address.Family().IsDomain() {

transport/internet/httpupgrade/dialer.go

@@ -10,6 +10,7 @@ import (
 	"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/utils"
 	"github.com/xtls/xray-core/transport/internet"
 	"github.com/xtls/xray-core/transport/internet/stat"
 	"github.com/xtls/xray-core/transport/internet/tls"
@@ -86,6 +87,9 @@ func dialhttpUpgrade(ctx context.Context, dest net.Destination, streamSettings *
 	for key, value := range transportConfiguration.Header {
 		AddHeader(req.Header, key, value)
 	}
+	if req.Header.Get("User-Agent") == "" {
+		req.Header.Set("User-Agent", utils.ChromeUA)
+	}
 	req.Header.Set("Connection", "Upgrade")
 	req.Header.Set("Upgrade", "websocket")
 

transport/internet/reality/reality.go

@@ -27,6 +27,7 @@ import (
 	"github.com/xtls/xray-core/common/crypto"
 	"github.com/xtls/xray-core/common/errors"
 	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/common/utils"
 	"github.com/xtls/xray-core/core"
 	"github.com/xtls/xray-core/transport/internet/tls"
 	"golang.org/x/crypto/hkdf"
@@ -222,7 +223,7 @@ func UClient(c net.Conn, config *Config, ctx context.Context, dest net.Destinati
 				if req == nil {
 					return
 				}
-				req.Header.Set("User-Agent", fingerprint.Client) // TODO: User-Agent map
+				req.Header.Set("User-Agent", utils.ChromeUA)
 				if first && config.Show {
 					fmt.Printf("REALITY localAddr: %v\treq.UserAgent(): %v\n", localAddr, req.UserAgent())
 				}

transport/internet/splithttp/config.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/crypto"
+	"github.com/xtls/xray-core/common/utils"
 	"github.com/xtls/xray-core/transport/internet"
 )
 
@@ -47,6 +48,9 @@ func (c *Config) GetRequestHeader() http.Header {
 	for k, v := range c.Headers {
 		header.Add(k, v)
 	}
+	if header.Get("User-Agent") == "" {
+		header.Set("User-Agent", utils.ChromeUA)
+	}
 	return header
 }
 

transport/internet/tls/ech.go

@@ -257,6 +257,7 @@ func dnsQuery(server string, domain string, sockopt *internet.SocketConfig) ([]b
 		}
 		req.Header.Set("Accept", "application/dns-message")
 		req.Header.Set("Content-Type", "application/dns-message")
+		req.Header.Set("User-Agent", utils.ChromeUA)
 		req.Header.Set("X-Padding", utils.H2Base62Pad(crypto.RandBetween(100, 1000)))
 
 		resp, err := client.Do(req)

transport/internet/websocket/config.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 
 	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/utils"
 	"github.com/xtls/xray-core/transport/internet"
 )
 
@@ -23,6 +24,9 @@ func (c *Config) GetRequestHeader() http.Header {
 	for k, v := range c.Header {
 		header.Add(k, v)
 	}
+	if header.Get("User-Agent") == "" {
+		header.Set("User-Agent", utils.ChromeUA)
+	}
 	return header
 }