From 2ab17e20af9ac60aa8c8b3c21aa7ea4716e9bd8e Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Mon, 8 May 2023 14:22:47 +0300
Subject: [PATCH] transport: increase the UDP send buffer size as well

---
 transport.go | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/transport.go b/transport.go
index 52f1a36a3..55bc7c488 100644
--- a/transport.go
+++ b/transport.go
@@ -270,7 +270,7 @@ func (t *Transport) close(e error) {
 }
 
 // only print warnings about the UDP receive buffer size once
-var receiveBufferWarningOnce sync.Once
+var setBufferWarningOnce sync.Once
 
 func (t *Transport) listen(conn rawConn) {
 	defer close(t.listening)
@@ -278,7 +278,17 @@ func (t *Transport) listen(conn rawConn) {
 
 	if err := setReceiveBuffer(t.Conn, t.logger); err != nil {
 		if !strings.Contains(err.Error(), "use of closed network connection") {
-			receiveBufferWarningOnce.Do(func() {
+			setBufferWarningOnce.Do(func() {
+				if disable, _ := strconv.ParseBool(os.Getenv("QUIC_GO_DISABLE_RECEIVE_BUFFER_WARNING")); disable {
+					return
+				}
+				log.Printf("%s. See https://github.com/quic-go/quic-go/wiki/UDP-Receive-Buffer-Size for details.", err)
+			})
+		}
+	}
+	if err := setSendBuffer(t.Conn, t.logger); err != nil {
+		if !strings.Contains(err.Error(), "use of closed network connection") {
+			setBufferWarningOnce.Do(func() {
 				if disable, _ := strconv.ParseBool(os.Getenv("QUIC_GO_DISABLE_RECEIVE_BUFFER_WARNING")); disable {
 					return
 				}