From b809f89411c70551bed0e9cc2466ddf8aa7c05b4 Mon Sep 17 00:00:00 2001
From: xjasonlyu <xjasonlyu@gmail.com>
Date: Mon, 3 Apr 2023 12:24:07 +0800
Subject: [PATCH] Revert: udp-rlybuf option

As a low-level networking tool, tun2socks should be able to handle UDP packets of all possible sizes. This reverts commit fb9ca959095eb53c21bafd09676d58a32aca1eed.
---
 Dockerfile       |  1 -
 engine/engine.go |  8 --------
 engine/key.go    |  1 -
 main.go          |  1 -
 tunnel/udp.go    | 15 +++------------
 5 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 596b75c..3dda97b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -22,7 +22,6 @@ ENV PROXY=direct://
 ENV MTU=9000
 ENV RESTAPI=
 ENV UDP_TIMEOUT=
-ENV UDP_RLYBUF=
 ENV TCP_SNDBUF=
 ENV TCP_RCVBUF=
 ENV TCP_AUTO_TUNING=
diff --git a/engine/engine.go b/engine/engine.go
index 6f7b743..52ff976 100644
--- a/engine/engine.go
+++ b/engine/engine.go
@@ -133,14 +133,6 @@ func general(k *Key) error {
 		}
 		tunnel.SetUDPTimeout(k.UDPTimeout)
 	}
-
-	if k.UDPRelayBufferSize != "" {
-		size, err := units.RAMInBytes(k.UDPRelayBufferSize)
-		if err != nil {
-			return err
-		}
-		tunnel.SetUDPRelayBufferSize(int(size))
-	}
 	return nil
 }
 
diff --git a/engine/key.go b/engine/key.go
index bc77500..d829ba7 100644
--- a/engine/key.go
+++ b/engine/key.go
@@ -14,7 +14,6 @@ type Key struct {
 	TCPSendBufferSize        string        `yaml:"tcp-send-buffer-size"`
 	TCPReceiveBufferSize     string        `yaml:"tcp-receive-buffer-size"`
 	TCPWaitTimeout           time.Duration `yaml:"tcp-wait-timeout"`
-	UDPRelayBufferSize       string        `yaml:"udp-relay-buffer-size"`
 	UDPTimeout               time.Duration `yaml:"udp-timeout"`
 	TUNPreUp                 string        `yaml:"tun-pre-up"`
 	TUNPostUp                string        `yaml:"tun-post-up"`
diff --git a/main.go b/main.go
index 8573c72..33f17ab 100644
--- a/main.go
+++ b/main.go
@@ -35,7 +35,6 @@ func init() {
 	flag.StringVar(&key.RestAPI, "restapi", "", "HTTP statistic server listen address")
 	flag.StringVar(&key.TCPSendBufferSize, "tcp-sndbuf", "", "Set TCP send buffer size for netstack")
 	flag.StringVar(&key.TCPReceiveBufferSize, "tcp-rcvbuf", "", "Set TCP receive buffer size for netstack")
-	flag.StringVar(&key.UDPRelayBufferSize, "udp-rlybuf", "", "Set UDP relay buffer size for tunnel")
 	flag.BoolVar(&key.TCPModerateReceiveBuffer, "tcp-auto-tuning", false, "Enable TCP receive buffer auto-tuning")
 	flag.DurationVar(&key.TCPWaitTimeout, "tcp-wait-timeout", 0, "Set timeout before closing each TCP connection")
 	flag.StringVar(&key.TUNPreUp, "tun-pre-up", "", "Execute a command before TUN device setup")
diff --git a/tunnel/udp.go b/tunnel/udp.go
index f5569db..5a3a17d 100644
--- a/tunnel/udp.go
+++ b/tunnel/udp.go
@@ -15,22 +15,13 @@ import (
 	"github.com/xjasonlyu/tun2socks/v2/tunnel/statistic"
 )
 
-var (
-	// _udpSessionTimeout is the default timeout for each UDP session.
-	_udpSessionTimeout = 60 * time.Second
-
-	// _udpRelayBufferSize is the default size for UDP packets relay.
-	_udpRelayBufferSize = 16 << 10
-)
+// _udpSessionTimeout is the default timeout for each UDP session.
+var _udpSessionTimeout = 60 * time.Second
 
 func SetUDPTimeout(t time.Duration) {
 	_udpSessionTimeout = t
 }
 
-func SetUDPRelayBufferSize(size int) {
-	_udpRelayBufferSize = size
-}
-
 // TODO: Port Restricted NAT support.
 func handleUDPConn(uc adapter.UDPConn) {
 	defer uc.Close()
@@ -93,7 +84,7 @@ func relayPacket(left net.PacketConn, right net.PacketConn, to net.Addr) error {
 }
 
 func copyPacketBuffer(dst net.PacketConn, src net.PacketConn, to net.Addr, timeout time.Duration) error {
-	buf := pool.Get(_udpRelayBufferSize)
+	buf := pool.Get(pool.MaxSegmentSize)
 	defer pool.Put(buf)
 
 	for {