From f973a7bee5ddc51280eea9883b545eefdcc3a7f7 Mon Sep 17 00:00:00 2001
From: adotkhan <61702862+adotkhan@users.noreply.github.com>
Date: Fri, 19 Jul 2024 10:03:27 -0400
Subject: [PATCH] fix: generate ClientHelloSpec only once (#306)

* fix: generate ClientHelloSpec only once

* chore: remove empty line in u_parrots.go

Co-authored-by: Gaukas Wang <i@gauk.as>
Signed-off-by: adotkhan <61702862+adotkhan@users.noreply.github.com>

---------

Signed-off-by: adotkhan <61702862+adotkhan@users.noreply.github.com>
Co-authored-by: Gaukas Wang <i@gauk.as>
---
 u_conn.go    |  1 +
 u_parrots.go | 38 ++++++++++++++++++++++----------------
 2 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/u_conn.go b/u_conn.go
index 49cc0f0e..753decdd 100644
--- a/u_conn.go
+++ b/u_conn.go
@@ -32,6 +32,7 @@ type UConn struct {
 	sessionController *sessionController
 
 	clientHelloBuildStatus ClientHelloBuildStatus
+	clientHelloSpec        *ClientHelloSpec
 
 	HandshakeState PubClientHandshakeState
 
diff --git a/u_parrots.go b/u_parrots.go
index 8ac1ca07..885b7431 100644
--- a/u_parrots.go
+++ b/u_parrots.go
@@ -2588,25 +2588,31 @@ func ShuffleChromeTLSExtensions(exts []TLSExtension) []TLSExtension {
 }
 
 func (uconn *UConn) applyPresetByID(id ClientHelloID) (err error) {
-	var spec ClientHelloSpec
-	uconn.ClientHelloID = id
-	// choose/generate the spec
-	switch id.Client {
-	case helloRandomized, helloRandomizedNoALPN, helloRandomizedALPN:
-		spec, err = uconn.generateRandomizedSpec()
-		if err != nil {
-			return err
-		}
-	case helloCustom:
-		return nil
-	default:
-		spec, err = UTLSIdToSpec(id)
-		if err != nil {
-			return err
+
+	if uconn.clientHelloSpec == nil {
+		var spec ClientHelloSpec
+		uconn.ClientHelloID = id
+
+		// choose/generate the spec
+		switch id.Client {
+		case helloRandomized, helloRandomizedNoALPN, helloRandomizedALPN:
+			spec, err = uconn.generateRandomizedSpec()
+			if err != nil {
+				return err
+			}
+		case helloCustom:
+			return nil
+		default:
+			spec, err = UTLSIdToSpec(id)
+			if err != nil {
+				return err
+			}
 		}
+
+		uconn.clientHelloSpec = &spec
 	}
 
-	return uconn.ApplyPreset(&spec)
+	return uconn.ApplyPreset(uconn.clientHelloSpec)
 }
 
 // ApplyPreset should only be used in conjunction with HelloCustom to apply custom specs.