chore: improve read waiter interface

go.mod

@@ -29,7 +29,7 @@ require (
 	github.com/openacid/low v0.1.21
 	github.com/oschwald/geoip2-golang v1.8.0
 	github.com/sagernet/netlink v0.0.0-20220905062125-8043b4a9aa97
-	github.com/sagernet/sing v0.2.5-0.20230510160026-237a991b46d0
+	github.com/sagernet/sing v0.2.5-0.20230512033628-9be7806bab51
 	github.com/sagernet/sing-mux v0.0.0-20230427141602-9836fc9b052e
 	github.com/sagernet/sing-shadowtls v0.1.2-0.20230417103049-4f682e05f19b
 	github.com/sagernet/sing-vmess v0.1.5-0.20230417103030-8c3070ae3fb3

go.sum

@@ -143,8 +143,8 @@ github.com/sagernet/netlink v0.0.0-20220905062125-8043b4a9aa97 h1:iL5gZI3uFp0X6E
 github.com/sagernet/netlink v0.0.0-20220905062125-8043b4a9aa97/go.mod h1:xLnfdiJbSp8rNqYEdIW/6eDO4mVoogml14Bh2hSiFpM=
 github.com/sagernet/sing v0.0.0-20220817130738-ce854cda8522/go.mod h1:QVsS5L/ZA2Q5UhQwLrn0Trw+msNd/NPGEhBKR/ioWiY=
 github.com/sagernet/sing v0.1.8/go.mod h1:jt1w2u7lJQFFSGLiRrRIs5YWmx4kAPfWuOejuDW9qMk=
-github.com/sagernet/sing v0.2.5-0.20230510160026-237a991b46d0 h1:NS4U+yQ4ToyRqFvCS91BM1D6fQbriW1qvioxSj5PvI4=
+github.com/sagernet/sing v0.2.5-0.20230512033628-9be7806bab51 h1:ySJuouhl890pBZly51Hkb2mbDnz+qSQCLF5j+4IFHis=
-github.com/sagernet/sing v0.2.5-0.20230510160026-237a991b46d0/go.mod h1:Ta8nHnDLAwqySzKhGoKk4ZIB+vJ3GTKj7UPrWYvM+4w=
+github.com/sagernet/sing v0.2.5-0.20230512033628-9be7806bab51/go.mod h1:Ta8nHnDLAwqySzKhGoKk4ZIB+vJ3GTKj7UPrWYvM+4w=
 github.com/sagernet/sing-mux v0.0.0-20230427141602-9836fc9b052e h1:t8nuY9plpHEzlnPxOpuv64jhjz3teIvccu3YMFX4fJI=
 github.com/sagernet/sing-mux v0.0.0-20230427141602-9836fc9b052e/go.mod h1:pF+RnLvCAOhECrvauy6LYOpBakJ/vuaF1Wm4lPsWryI=
 github.com/sagernet/sing-shadowtls v0.1.2-0.20230417103049-4f682e05f19b h1:ouW/6IDCrxkBe19YSbdCd7buHix7b+UZ6BM4Zz74XF4=

listener/sing/sing.go

@@ -124,21 +124,23 @@ func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.
 		defer mutex.Unlock()
 		conn2 = nil
 	}()
-	connReader := network.UnwrapPacketReader(conn) // decrease runtime cost for bufio.CreatePacketReadWaiter
+	var buff *buf.Buffer
-	for {
-		var (
-			buff *buf.Buffer
-			dest M.Socksaddr
-			err  error
-		)
 	newBuffer := func() *buf.Buffer {
 		buff = buf.NewPacket() // do not use stack buffer
 		return buff
 	}
-		// syscallPacketReadWaiter.WaitReadPacket will cache newBuffer function
+	readWaiter, isReadWaiter := bufio.CreatePacketReadWaiter(conn)
-		// so create new PacketReadWaiter in each loop
+	if isReadWaiter {
-		if readWaiter, isReadWaiter := bufio.CreatePacketReadWaiter(connReader); isReadWaiter {
+		readWaiter.InitializeReadWaiter(newBuffer)
-			dest, err = readWaiter.WaitReadPacket(newBuffer)
+	}
+	for {
+		var (
+			dest M.Socksaddr
+			err  error
+		)
+		buff = nil // clear last loop status, avoid repeat release
+		if isReadWaiter {
+			dest, err = readWaiter.WaitReadPacket()
 		} else {
 			dest, err = conn.ReadPacket(newBuffer())
 		}

listener/sing_shadowsocks/server.go

@@ -22,7 +22,6 @@ import (
 	"github.com/sagernet/sing/common/buf"
 	"github.com/sagernet/sing/common/bufio"
 	M "github.com/sagernet/sing/common/metadata"
-	"github.com/sagernet/sing/common/network"
 )
 
 type Listener struct {
@@ -93,21 +92,23 @@ func New(config LC.ShadowsocksServer, tcpIn chan<- C.ConnContext, udpIn chan<- C
 
 			go func() {
 				conn := bufio.NewPacketConn(ul)
-				connReader := network.UnwrapPacketReader(conn) // decrease runtime cost for bufio.CreatePacketReadWaiter
+				var buff *buf.Buffer
-				for {
-					var (
-						buff *buf.Buffer
-						dest M.Socksaddr
-						err  error
-					)
 				newBuffer := func() *buf.Buffer {
 					buff = buf.NewPacket() // do not use stack buffer
 					return buff
 				}
-					// syscallPacketReadWaiter.WaitReadPacket will cache newBuffer function
+				readWaiter, isReadWaiter := bufio.CreatePacketReadWaiter(conn)
-					// so create new PacketReadWaiter in each loop
+				if isReadWaiter {
-					if readWaiter, isReadWaiter := bufio.CreatePacketReadWaiter(connReader); isReadWaiter {
+					readWaiter.InitializeReadWaiter(newBuffer)
-						dest, err = readWaiter.WaitReadPacket(newBuffer)
+				}
+				for {
+					var (
+						dest M.Socksaddr
+						err  error
+					)
+					buff = nil // clear last loop status, avoid repeat release
+					if isReadWaiter {
+						dest, err = readWaiter.WaitReadPacket()
 					} else {
 						dest, err = conn.ReadPacket(newBuffer())
 					}

listener/sing_tun/dns.go

@@ -110,24 +110,26 @@ func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.
 			conn2 = nil
 		}()
 
-		connReader := network.UnwrapPacketReader(conn) // decrease runtime cost for bufio.CreatePacketReadWaiter
+		var buff *buf.Buffer
-		for {
-			var (
-				buff *buf.Buffer
-				dest M.Socksaddr
-				err  error
-			)
 		newBuffer := func() *buf.Buffer {
 			// safe size which is 1232 from https://dnsflagday.net/2020/.
 			// so 2048 is enough
 			buff = buf.NewSize(2 * 1024)
 			return buff
 		}
+		readWaiter, isReadWaiter := bufio.CreatePacketReadWaiter(conn)
+		if isReadWaiter {
+			readWaiter.InitializeReadWaiter(newBuffer)
+		}
+		for {
+			var (
+				dest M.Socksaddr
+				err  error
+			)
 			_ = conn.SetReadDeadline(time.Now().Add(DefaultDnsReadTimeout))
-			// syscallPacketReadWaiter.WaitReadPacket will cache newBuffer function
+			buff = nil // clear last loop status, avoid repeat release
-			// so create new PacketReadWaiter in each loop
+			if isReadWaiter {
-			if readWaiter, isReadWaiter := bufio.CreatePacketReadWaiter(connReader); isReadWaiter {
+				dest, err = readWaiter.WaitReadPacket()
-				dest, err = readWaiter.WaitReadPacket(newBuffer)
 			} else {
 				dest, err = conn.ReadPacket(newBuffer())
 			}
@@ -140,7 +142,7 @@ func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.
 				}
 				return err
 			}
-			go func() {
+			go func(buff *buf.Buffer) {
 				ctx, cancel := context.WithTimeout(ctx, DefaultDnsRelayTimeout)
 				defer cancel()
 				inData := buff.Bytes()
@@ -165,7 +167,7 @@ func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.
 				if err != nil {
 					return
 				}
-			}()
+			}(buff) // catch buff at goroutine create, avoid next loop change buff
 		}
 		return nil
 	}