REALITY, TLS config: Set "chrome" as the default fingerprint

Other VLESS implementations should follow this change.

infra/conf/transport_internet.go

@@ -438,7 +438,7 @@ func (c *TLSConfig) Build() (proto.Message, error) {
 	config.MaxVersion = c.MaxVersion
 	config.CipherSuites = c.CipherSuites
 	config.Fingerprint = strings.ToLower(c.Fingerprint)
-	if config.Fingerprint != "" && tls.GetFingerprint(config.Fingerprint) == nil {
+	if config.Fingerprint != "unsafe" && tls.GetFingerprint(config.Fingerprint) == nil {
 		return nil, errors.New(`unknown fingerprint: `, config.Fingerprint)
 	}
 	config.RejectUnknownSni = c.RejectUnknownSNI
@@ -584,15 +584,13 @@ func (c *REALITYConfig) Build() (proto.Message, error) {
 		config.ServerNames = c.ServerNames
 		config.MaxTimeDiff = c.MaxTimeDiff
 	} else {
-		if c.Fingerprint == "" {
-			return nil, errors.New(`empty "fingerprint"`)
-		}
-		if config.Fingerprint = strings.ToLower(c.Fingerprint); tls.GetFingerprint(config.Fingerprint) == nil {
-			return nil, errors.New(`unknown "fingerprint": `, config.Fingerprint)
-		}
-		if config.Fingerprint == "hellogolang" {
+		config.Fingerprint = strings.ToLower(c.Fingerprint)
+		if config.Fingerprint == "unsafe" || config.Fingerprint == "hellogolang" {
 			return nil, errors.New(`invalid "fingerprint": `, config.Fingerprint)
 		}
+		if tls.GetFingerprint(config.Fingerprint) == nil {
+			return nil, errors.New(`unknown "fingerprint": `, config.Fingerprint)
+		}
 		if len(c.ServerNames) != 0 {
 			return nil, errors.New(`non-empty "serverNames", please use "serverName" instead`)
 		}

transport/internet/tls/tls.go

@@ -165,7 +165,7 @@ func init() {
 
 func GetFingerprint(name string) (fingerprint *utls.ClientHelloID) {
 	if name == "" {
-		return
+		return &utls.HelloChrome_Auto
 	}
 	if fingerprint = PresetFingerprints[name]; fingerprint != nil {
 		return
@@ -191,6 +191,7 @@ var PresetFingerprints = map[string]*utls.ClientHelloID{
 	"qq":         &utls.HelloQQ_Auto,
 	"random":     nil,
 	"randomized": nil,
+	"unsafe":     nil,
 }
 
 var ModernFingerprints = map[string]*utls.ClientHelloID{