From 282c5f94f07c803d947ff07eb9dd150123fb0ede Mon Sep 17 00:00:00 2001
From: Gray Liang <gray.liang@isovalent.com>
Date: Fri, 5 Jan 2024 20:08:10 +0800
Subject: [PATCH] Use netns only if EADDRINUSE occurred

---
 control/anyfrom_pool.go |  6 +-----
 control/udp.go          | 17 ++++++++---------
 2 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/control/anyfrom_pool.go b/control/anyfrom_pool.go
index b10354ff54..f7206178db 100644
--- a/control/anyfrom_pool.go
+++ b/control/anyfrom_pool.go
@@ -190,11 +190,7 @@ func (p *AnyfromPool) GetOrCreate(lAddr string, ttl time.Duration) (conn *Anyfro
 			},
 			KeepAlive: 0,
 		}
-		var pc net.PacketConn
-		err := WithIndieNetns(func() (err error) {
-			pc, err = d.ListenPacket(context.Background(), "udp", lAddr)
-			return err
-		})
+		pc, err := d.ListenPacket(context.Background(), "udp", lAddr)
 		if err != nil {
 			return nil, true, err
 		}
diff --git a/control/udp.go b/control/udp.go
index e0ed524c2a..d3c380ef09 100644
--- a/control/udp.go
+++ b/control/udp.go
@@ -90,17 +90,16 @@ func sendPkt(data []byte, from netip.AddrPort, realTo, to netip.AddrPort, lConn
 	}
 
 	uConn, _, err := DefaultAnyfromPool.GetOrCreate(from.String(), AnyfromTimeout)
-	if err != nil {
-		if errors.Is(err, syscall.EADDRINUSE) {
-			// Port collision, use traditional method.
-			return sendPktWithHdrWithFlag(data, from, lConn, to, lanWanFlag)
-		}
-		return err
+	if err != nil && errors.Is(err, syscall.EADDRINUSE) {
+		err = WithIndieNetns(func() (err error) {
+			uConn, _, err = DefaultAnyfromPool.GetOrCreate(from.String(), AnyfromTimeout)
+			return err
+		})
 	}
-	err = WithIndieNetns(func() (err error) {
-		_, err = uConn.WriteToUDPAddrPort(data, realTo)
+	if err != nil {
 		return
-	})
+	}
+	_, err = uConn.WriteToUDPAddrPort(data, realTo)
 	return err
 }