From 60f0a0369b1829f02205a1a77246412cf9366645 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=96=E7=95=8C?= <i@sekai.icu>
Date: Sun, 20 Sep 2026 17:36:19 +0800
Subject: [PATCH] Fix half-close not propagating through connection wrappers

---
 common/badtls/read_wait.go   |  4 ++++
 common/tls/reality_client.go |  2 +-
 common/tls/reality_server.go |  2 +-
 go.mod                       |  2 +-
 go.sum                       |  4 ++--
 route/conn.go                | 16 ++++++++++------
 6 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/common/badtls/read_wait.go b/common/badtls/read_wait.go
index 8448b1a2..982f0f17 100644
--- a/common/badtls/read_wait.go
+++ b/common/badtls/read_wait.go
@@ -80,3 +80,7 @@ func (c *ReadWaitConn) Upstream() any {
 func (c *ReadWaitConn) ReaderReplaceable() bool {
 	return true
 }
+
+func (c *ReadWaitConn) WriterReplaceable() bool {
+	return true
+}
diff --git a/common/tls/reality_client.go b/common/tls/reality_client.go
index af64ef6f..13f88e38 100644
--- a/common/tls/reality_client.go
+++ b/common/tls/reality_client.go
@@ -343,5 +343,5 @@ func (c *realityClientConnWrapper) ReaderReplaceable() bool {
 }
 
 func (c *realityClientConnWrapper) WriterReplaceable() bool {
-	return true
+	return false
 }
diff --git a/common/tls/reality_server.go b/common/tls/reality_server.go
index 10d60618..8ad59e14 100644
--- a/common/tls/reality_server.go
+++ b/common/tls/reality_server.go
@@ -254,5 +254,5 @@ func (c *realityConnWrapper) ReaderReplaceable() bool {
 }
 
 func (c *realityConnWrapper) WriterReplaceable() bool {
-	return true
+	return false
 }
diff --git a/go.mod b/go.mod
index 4cd26fa1..af91c67f 100644
--- a/go.mod
+++ b/go.mod
@@ -45,7 +45,7 @@ require (
 	github.com/sagernet/netlink v0.0.0-20260814022025-64455d367bbf
 	github.com/sagernet/nftables v0.3.0-mod.4
 	github.com/sagernet/quic-go v0.61.0-sing-box-mod.7
-	github.com/sagernet/sing v0.9.6-0.20260920042621-643b9d01347d
+	github.com/sagernet/sing v0.9.6-0.20260920093512-38496bf4f1df
 	github.com/sagernet/sing-cloudflared v0.1.3-0.20260706062323-d9787e794aa3
 	github.com/sagernet/sing-mux v0.3.8
 	github.com/sagernet/sing-openconnect v0.0.0-20260810065514-53aa8058f8df
diff --git a/go.sum b/go.sum
index 1d604331..56b41eb1 100644
--- a/go.sum
+++ b/go.sum
@@ -318,8 +318,8 @@ github.com/sagernet/nftables v0.3.0-mod.4 h1:vnOtcDYeSXv2e5RoRuGH0lrpttQFJ8iC4IC
 github.com/sagernet/nftables v0.3.0-mod.4/go.mod h1:8kslHG4VvYNihcco+i6uxIX7qbT8A56T0y5q7U44ZaQ=
 github.com/sagernet/quic-go v0.61.0-sing-box-mod.7 h1:sW2O+DoNF+my1PGlSZ3zG2N+fdxLR3DC0l4sXCM0lBE=
 github.com/sagernet/quic-go v0.61.0-sing-box-mod.7/go.mod h1:hmLC8GJPp+BrpBgrgJnacvI4fZGIhasuy1ROJJ8GR4E=
-github.com/sagernet/sing v0.9.6-0.20260920042621-643b9d01347d h1:4HL9hWcaBCAyIm4bPWxTtWa4Oz4YcLgSvLcjVIQdpdY=
-github.com/sagernet/sing v0.9.6-0.20260920042621-643b9d01347d/go.mod h1:K3Owt3xPhHugvlnlPPxZJ/exXdaJfEPOTNorGk4AXjo=
+github.com/sagernet/sing v0.9.6-0.20260920093512-38496bf4f1df h1:KZSoa3WMDGrr7rCJOUfg0mgxvTkSWcsPk4dzRdt2+YQ=
+github.com/sagernet/sing v0.9.6-0.20260920093512-38496bf4f1df/go.mod h1:K3Owt3xPhHugvlnlPPxZJ/exXdaJfEPOTNorGk4AXjo=
 github.com/sagernet/sing-cloudflared v0.1.3-0.20260706062323-d9787e794aa3 h1:3y6++yIa8XlDhxPkpR4p+7RUHVY2KTP9CPIGnWmOlO8=
 github.com/sagernet/sing-cloudflared v0.1.3-0.20260706062323-d9787e794aa3/go.mod h1:XEqEDYRCAYLaoPjZ1ifVWJg5iWAJHL2gOAXe/PM28Cg=
 github.com/sagernet/sing-mux v0.3.8 h1:mM0TLUkr36aEhgUHi9Qh60qcAbD2fZcmnJ30937xxrY=
diff --git a/route/conn.go b/route/conn.go
index c2ab90d5..fe718b50 100644
--- a/route/conn.go
+++ b/route/conn.go
@@ -274,13 +274,17 @@ func (m *ConnectionManager) connectionCopy(ctx context.Context, source net.Conn,
 	_, err := bufio.CopyWithIncreateBuffer(destination, source, bufio.DefaultIncreaseBufferAfter, bufio.DefaultBatchSize)
 	if err != nil {
 		common.Close(source, destination)
-	} else if duplexDst, isDuplex := destination.(N.WriteCloser); isDuplex {
-		err = duplexDst.CloseWrite()
-		if err != nil {
-			common.Close(source, destination)
-		}
 	} else {
-		destination.Close()
+		destinationWriter, _ := N.UnwrapCountWriter(destination, nil)
+		duplexDst, isDuplex := N.UnwrapWriter(destinationWriter).(N.WriteCloser)
+		if isDuplex {
+			err = duplexDst.CloseWrite()
+			if err != nil {
+				common.Close(source, destination)
+			}
+		} else {
+			destination.Close()
+		}
 	}
 	if done.Swap(true) {
 		if onClose != nil {