From 1a9104c003707e23dc2612f23a2ef73792a97b77 Mon Sep 17 00:00:00 2001
From: wwqgtxx <wwqgtxx@gmail.com>
Date: Mon, 15 May 2023 19:06:58 +0800
Subject: [PATCH] fix: UDP packet should not return io.EOF

---
 common/net/packet/packet_posix.go | 9 +++++----
 go.mod                            | 2 +-
 go.sum                            | 4 ++--
 tunnel/connection.go              | 4 +++-
 4 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/common/net/packet/packet_posix.go b/common/net/packet/packet_posix.go
index 3c5d23a6..2861482f 100644
--- a/common/net/packet/packet_posix.go
+++ b/common/net/packet/packet_posix.go
@@ -3,7 +3,6 @@
 package packet
 
 import (
-	"io"
 	"net"
 	"strconv"
 	"syscall"
@@ -34,6 +33,7 @@ func (c *enhanceUDPConn) WaitReadFrom() (data []byte, put func(), addr net.Addr,
 		} else {
 			put()
 			put = nil
+			data = nil
 		}
 		if readErr == syscall.EAGAIN {
 			return false
@@ -48,9 +48,10 @@ func (c *enhanceUDPConn) WaitReadFrom() (data []byte, put func(), addr net.Addr,
 				addr = &net.UDPAddr{IP: ip[:], Port: from.Port, Zone: strconv.FormatInt(int64(from.ZoneId), 10)}
 			}
 		}
-		if readN == 0 {
-			readErr = io.EOF
-		}
+		// udp should not convert readN == 0 to io.EOF
+		//if readN == 0 {
+		//	readErr = io.EOF
+		//}
 		return true
 	})
 	if err != nil {
diff --git a/go.mod b/go.mod
index 9b1e2dbd..3ecee7a1 100644
--- a/go.mod
+++ b/go.mod
@@ -21,7 +21,7 @@ require (
 	github.com/mdlayher/netlink v1.7.2
 	github.com/metacubex/quic-go v0.33.3-0.20230510010206-687b537b6a58
 	github.com/metacubex/sing-shadowsocks v0.2.2-0.20230509230448-a5157cc00a1c
-	github.com/metacubex/sing-shadowsocks2 v0.0.0-20230511124108-b20f64384bdd
+	github.com/metacubex/sing-shadowsocks2 v0.0.0-20230515071211-0c3604faef69
 	github.com/metacubex/sing-tun v0.1.5-0.20230509224930-30065d4b6376
 	github.com/metacubex/sing-wireguard v0.0.0-20230426030325-41db09ae771a
 	github.com/miekg/dns v1.1.54
diff --git a/go.sum b/go.sum
index d38293a3..80d18133 100644
--- a/go.sum
+++ b/go.sum
@@ -98,8 +98,8 @@ github.com/metacubex/quic-go v0.33.3-0.20230510010206-687b537b6a58 h1:E/sNW9tugF
 github.com/metacubex/quic-go v0.33.3-0.20230510010206-687b537b6a58/go.mod h1:9nOiGX6kqV3+ZbkDKdTNzdFD726QQHPH6WDb36jUSpA=
 github.com/metacubex/sing-shadowsocks v0.2.2-0.20230509230448-a5157cc00a1c h1:LpVNvlW/xE+mR8z76xJeYZlYznZXEmU4TeWeuygYdJg=
 github.com/metacubex/sing-shadowsocks v0.2.2-0.20230509230448-a5157cc00a1c/go.mod h1:4uQQReKMTU7KTfOykVBe/oGJ00pl38d+BYJ99+mx26s=
-github.com/metacubex/sing-shadowsocks2 v0.0.0-20230511124108-b20f64384bdd h1:RXdD763CbvqaJOyFLAh6xa8xg7BZTkOJ0p8fBc7kB+w=
-github.com/metacubex/sing-shadowsocks2 v0.0.0-20230511124108-b20f64384bdd/go.mod h1:r+JnKYxqLJIkRhpT9xb3b11icXsvM6yVjCxr2Smp1Og=
+github.com/metacubex/sing-shadowsocks2 v0.0.0-20230515071211-0c3604faef69 h1:6mwe6TyQUqjpqu8QwRlY5xR5VjENzXtM3LVRhjq00nw=
+github.com/metacubex/sing-shadowsocks2 v0.0.0-20230515071211-0c3604faef69/go.mod h1:r+JnKYxqLJIkRhpT9xb3b11icXsvM6yVjCxr2Smp1Og=
 github.com/metacubex/sing-tun v0.1.5-0.20230509224930-30065d4b6376 h1:zKNsbFQyleMFAP7NJYRew9sEMJuniuODH3V0FdWnEtk=
 github.com/metacubex/sing-tun v0.1.5-0.20230509224930-30065d4b6376/go.mod h1:BMfG00enVf90/CzcdX9PK3Dymgl7BZqHXJfexEyB7Cc=
 github.com/metacubex/sing-wireguard v0.0.0-20230426030325-41db09ae771a h1:cWKym33Qvl6HA3hj4/YuYD8hHyqQPb47wT5cJRAPgco=
diff --git a/tunnel/connection.go b/tunnel/connection.go
index 73c3e499..321c7d06 100644
--- a/tunnel/connection.go
+++ b/tunnel/connection.go
@@ -55,7 +55,9 @@ func handleUDPToLocal(packet C.UDPPacket, pc N.EnhancePacketConn, key string, oA
 		}
 
 		_, err = packet.WriteBack(data, fromUDPAddr)
-		put()
+		if put != nil {
+			put()
+		}
 		if err != nil {
 			return
 		}