chore: hysteria2 add udp-mtu option

default value is `1200-3` to match old version quic-go's capability

adapter/outbound/hysteria2.go

@@ -50,6 +50,7 @@ type Hysteria2Option struct {
 	CustomCA       string   `proxy:"ca,omitempty"`
 	CustomCAString string   `proxy:"ca-str,omitempty"`
 	CWND           int      `proxy:"cwnd,omitempty"`
+	UdpMTU         int      `proxy:"udp-mtu,omitempty"`
 }
 
 func (h *Hysteria2) DialContext(ctx context.Context, metadata *C.Metadata, opts ...dialer.Option) (_ C.Conn, err error) {
@@ -117,6 +118,12 @@ func NewHysteria2(option Hysteria2Option) (*Hysteria2, error) {
 		tlsConfig.NextProtos = option.ALPN
 	}
 
+	if option.UdpMTU == 0 {
+		// "1200" from quic-go's MaxDatagramSize
+		// "-3" from quic-go's DatagramFrame.MaxDataLen
+		option.UdpMTU = 1200 - 3
+	}
+
 	singDialer := proxydialer.NewByNameSingDialer(option.DialerProxy, dialer.NewDialer())
 
 	clientOptions := hysteria2.ClientOptions{
@@ -130,6 +137,7 @@ func NewHysteria2(option Hysteria2Option) (*Hysteria2, error) {
 		TLSConfig:          tlsConfig,
 		UDPDisabled:        false,
 		CWND:               option.CWND,
+		UdpMTU:             option.UdpMTU,
 	}
 
 	client, err := hysteria2.NewClient(clientOptions)

go.mod

@@ -21,7 +21,7 @@ require (
 	github.com/mdlayher/netlink v1.7.2
 	github.com/metacubex/gopacket v1.1.20-0.20230608035415-7e2f98a3e759
 	github.com/metacubex/quic-go v0.41.1-0.20240120014142-a02f4a533d4a
-	github.com/metacubex/sing-quic v0.0.0-20240120014430-9838ce4bbc41
+	github.com/metacubex/sing-quic v0.0.0-20240122125415-d6eb83bc6ec4
 	github.com/metacubex/sing-shadowsocks v0.2.6
 	github.com/metacubex/sing-shadowsocks2 v0.2.0
 	github.com/metacubex/sing-tun v0.2.0

go.sum

@@ -110,8 +110,8 @@ github.com/metacubex/quic-go v0.41.1-0.20240120014142-a02f4a533d4a h1:IMr75VdMnD
 github.com/metacubex/quic-go v0.41.1-0.20240120014142-a02f4a533d4a/go.mod h1:F/t8VnA47xoia8ABlNA4InkZjssvFJ5p6E6jKdbkgAs=
 github.com/metacubex/sing v0.0.0-20240111014253-f1818b6a82b2 h1:upEO8dt9WDBavhgcgkXB3hRcwVNbkTbnd+xyzy6ZQZo=
 github.com/metacubex/sing v0.0.0-20240111014253-f1818b6a82b2/go.mod h1:9pfuAH6mZfgnz/YjP6xu5sxx882rfyjpcrTdUpd6w3g=
-github.com/metacubex/sing-quic v0.0.0-20240120014430-9838ce4bbc41 h1:nBo+cgprEu5f6vfJ2lpNvoUh13QUWR3oq1Bul9iF9HY=
+github.com/metacubex/sing-quic v0.0.0-20240122125415-d6eb83bc6ec4 h1:4EukI/UdbuaXov7VDDZf4vaP0ZmkUu827DOeQqzVysw=
-github.com/metacubex/sing-quic v0.0.0-20240120014430-9838ce4bbc41/go.mod h1:bdHqEysJclB9BzIa5jcKKSZ1qua+YEPjR8fOzzE3vZU=
+github.com/metacubex/sing-quic v0.0.0-20240122125415-d6eb83bc6ec4/go.mod h1:bdHqEysJclB9BzIa5jcKKSZ1qua+YEPjR8fOzzE3vZU=
 github.com/metacubex/sing-shadowsocks v0.2.6 h1:6oEB3QcsFYnNiFeoevcXrCwJ3sAablwVSgtE9R3QeFQ=
 github.com/metacubex/sing-shadowsocks v0.2.6/go.mod h1:zIkMeSnb8Mbf4hdqhw0pjzkn1d99YJ3JQm/VBg5WMTg=
 github.com/metacubex/sing-shadowsocks2 v0.2.0 h1:hqwT/AfI5d5UdPefIzR6onGHJfDXs5zgOM5QSgaM/9A=

listener/config/hysteria2.go

@@ -21,6 +21,7 @@ type Hysteria2Server struct {
 	IgnoreClientBandwidth bool              `yaml:"ignore-client-bandwidth" json:"ignore-client-bandwidth,omitempty"`
 	Masquerade            string            `yaml:"masquerade" json:"masquerade,omitempty"`
 	CWND                  int               `yaml:"cwnd" json:"cwnd,omitempty"`
+	UdpMTU                int               `yaml:"udp-mtu" json:"udp-mtu,omitempty"`
 	MuxOption             sing.MuxOption    `yaml:"mux-option" json:"mux-option,omitempty"`
 }
 

listener/inbound/hysteria2.go

@@ -21,6 +21,7 @@ type Hysteria2Option struct {
 	IgnoreClientBandwidth bool              `inbound:"ignore-client-bandwidth,omitempty"`
 	Masquerade            string            `inbound:"masquerade,omitempty"`
 	CWND                  int               `inbound:"cwnd,omitempty"`
+	UdpMTU                int               `inbound:"udp-mtu,omitempty"`
 	MuxOption             MuxOption         `inbound:"mux-option,omitempty"`
 }
 
@@ -58,6 +59,7 @@ func NewHysteria2(options *Hysteria2Option) (*Hysteria2, error) {
 			IgnoreClientBandwidth: options.IgnoreClientBandwidth,
 			Masquerade:            options.Masquerade,
 			CWND:                  options.CWND,
+			UdpMTU:                options.UdpMTU,
 			MuxOption:             options.MuxOption.Build(),
 		},
 	}, nil

listener/sing_hysteria2/server.go

@@ -104,6 +104,12 @@ func New(config LC.Hysteria2Server, tunnel C.Tunnel, additions ...inbound.Additi
 		}
 	}
 
+	if config.UdpMTU == 0 {
+		// "1200" from quic-go's MaxDatagramSize
+		// "-3" from quic-go's DatagramFrame.MaxDataLen
+		config.UdpMTU = 1200 - 3
+	}
+
 	service, err := hysteria2.NewService[string](hysteria2.ServiceOptions{
 		Context:               context.Background(),
 		Logger:                log.SingLogger,
@@ -115,6 +121,7 @@ func New(config LC.Hysteria2Server, tunnel C.Tunnel, additions ...inbound.Additi
 		Handler:               h,
 		MasqueradeHandler:     masqueradeHandler,
 		CWND:                  config.CWND,
+		UdpMTU:                config.UdpMTU,
 	})
 	if err != nil {
 		return nil, err

transport/tuic/v5/frag.go

@@ -12,7 +12,9 @@ import (
 // MaxFragSize is a safe udp relay packet size
 // because tuicv5 support udp fragment so we unneeded to do a magic modify for quic-go to increase MaxDatagramFrameSize
 // it may not work fine in some platform
-var MaxFragSize = 1200 - PacketOverHead
+// "1200" from quic-go's MaxDatagramSize
+// "-3" from quic-go's DatagramFrame.MaxDataLen
+var MaxFragSize = 1200 - PacketOverHead - 3
 
 func fragWriteNative(quicConn quic.Connection, packet Packet, buf *bytes.Buffer, fragSize int) (err error) {
 	fullPayload := packet.DATA