From bcb301b730de889295d7f90ccf8aa8102f133727 Mon Sep 17 00:00:00 2001
From: Dreamacro <8615343+Dreamacro@users.noreply.github.com>
Date: Wed, 3 Nov 2021 22:26:51 +0800
Subject: [PATCH] Chore: adjust all udp alloc size

---
 common/pool/pool.go    | 5 +++++
 listener/socks/udp.go  | 2 +-
 listener/tproxy/udp.go | 2 +-
 tunnel/connection.go   | 2 +-
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/common/pool/pool.go b/common/pool/pool.go
index e6354f11..bee4887f 100644
--- a/common/pool/pool.go
+++ b/common/pool/pool.go
@@ -5,6 +5,11 @@ const (
 	// but the maximum packet size of vmess/shadowsocks is about 16 KiB
 	// so define a buffer of 20 KiB to reduce the memory of each TCP relay
 	RelayBufferSize = 20 * 1024
+
+	// RelayBufferSize uses 20KiB, but due to the allocator it will actually
+	// request 32Kib. Most UDPs are smaller than the MTU, and the TUN's MTU
+	// set to 9000, so the UDP Buffer size set to 16Kib
+	UDPBufferSize = 16 * 1024
 )
 
 func Get(size int) []byte {
diff --git a/listener/socks/udp.go b/listener/socks/udp.go
index a2d21508..8bc439fb 100644
--- a/listener/socks/udp.go
+++ b/listener/socks/udp.go
@@ -49,7 +49,7 @@ func NewUDP(addr string, in chan<- *inbound.PacketAdapter) (*UDPListener, error)
 	}
 	go func() {
 		for {
-			buf := pool.Get(pool.RelayBufferSize)
+			buf := pool.Get(pool.UDPBufferSize)
 			n, remoteAddr, err := l.ReadFrom(buf)
 			if err != nil {
 				pool.Put(buf)
diff --git a/listener/tproxy/udp.go b/listener/tproxy/udp.go
index f3d8dbb3..c7e6d99e 100644
--- a/listener/tproxy/udp.go
+++ b/listener/tproxy/udp.go
@@ -57,7 +57,7 @@ func NewUDP(addr string, in chan<- *inbound.PacketAdapter) (*UDPListener, error)
 	go func() {
 		oob := make([]byte, 1024)
 		for {
-			buf := pool.Get(pool.RelayBufferSize)
+			buf := pool.Get(pool.UDPBufferSize)
 			n, oobn, _, lAddr, err := c.ReadMsgUDP(buf, oob)
 			if err != nil {
 				pool.Put(buf)
diff --git a/tunnel/connection.go b/tunnel/connection.go
index 8c3b4cb6..45de46d7 100644
--- a/tunnel/connection.go
+++ b/tunnel/connection.go
@@ -39,7 +39,7 @@ func handleUDPToRemote(packet C.UDPPacket, pc C.PacketConn, metadata *C.Metadata
 }
 
 func handleUDPToLocal(packet C.UDPPacket, pc net.PacketConn, key string, fAddr net.Addr) {
-	buf := pool.Get(pool.RelayBufferSize)
+	buf := pool.Get(pool.UDPBufferSize)
 	defer pool.Put(buf)
 	defer natTable.Delete(key)
 	defer pc.Close()