Add reserved to WireGuard config

Fixes https://github.com/XTLS/Xray-core/issues/1730

infra/conf/wireguard.go

@@ -52,6 +52,7 @@ type WireGuardConfig struct {
 	Peers      []*WireGuardPeerConfig `json:"peers"`
 	MTU        int                    `json:"mtu"`
 	NumWorkers int                    `json:"workers"`
+	Reserved   []byte                 `json:"reserved"`
 }
 
 func (c *WireGuardConfig) Build() (proto.Message, error) {
@@ -90,6 +91,11 @@ func (c *WireGuardConfig) Build() (proto.Message, error) {
 	// we don't need to process fallback manually
 	config.NumWorkers = int32(c.NumWorkers)
 
+	if len(c.Reserved) != 0 && len(c.Reserved) != 3 {
+		return nil, newError(`"reserved" should be empty or 3 bytes`)
+	}
+	config.Reserved = c.Reserved
+
 	return config, nil
 }
 

proxy/wireguard/bind.go

@@ -31,6 +31,7 @@ type netBindClient struct {
 	dialer    internet.Dialer
 	dns       dns.Client
 	dnsOption dns.IPOption
+	reserved  []byte
 
 	readQueue chan *netReadInfo
 }
@@ -157,6 +158,10 @@ func (bind *netBindClient) Send(buff []byte, endpoint conn.Endpoint) error {
 		}
 	}
 
+	if len(buff) > 3 && len(bind.reserved) == 3 {
+		copy(buff[1:], bind.reserved)
+	}
+
 	_, err = nend.conn.Write(buff)
 
 	return err

proxy/wireguard/config.pb.go

@@ -109,6 +109,7 @@ type DeviceConfig struct {
 	Peers      []*PeerConfig `protobuf:"bytes,3,rep,name=peers,proto3" json:"peers,omitempty"`
 	Mtu        int32         `protobuf:"varint,4,opt,name=mtu,proto3" json:"mtu,omitempty"`
 	NumWorkers int32         `protobuf:"varint,5,opt,name=num_workers,json=numWorkers,proto3" json:"num_workers,omitempty"`
+	Reserved   []byte        `protobuf:"bytes,6,opt,name=reserved,proto3" json:"reserved,omitempty"`
 }
 
 func (x *DeviceConfig) Reset() {
@@ -178,6 +179,13 @@ func (x *DeviceConfig) GetNumWorkers() int32 {
 	return 0
 }
 
+func (x *DeviceConfig) GetReserved() []byte {
+	if x != nil {
+		return x.Reserved
+	}
+	return nil
+}
+
 var File_proxy_wireguard_config_proto protoreflect.FileDescriptor
 
 var file_proxy_wireguard_config_proto_rawDesc = []byte{
@@ -195,7 +203,7 @@ var file_proxy_wireguard_config_proto_rawDesc = []byte{
 	0x76, 0x65, 0x18, 0x04, 0x20, 0x01, 0x28, 0x05, 0x52, 0x09, 0x6b, 0x65, 0x65, 0x70, 0x41, 0x6c,
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@@ -206,14 +214,15 @@ var file_proxy_wireguard_config_proto_rawDesc = []byte{
 	0x67, 0x52, 0x05, 0x70, 0x65, 0x65, 0x72, 0x73, 0x12, 0x10, 0x0a, 0x03, 0x6d, 0x74, 0x75, 0x18,
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 }
 
 var (

proxy/wireguard/config.proto

@@ -20,4 +20,5 @@ message DeviceConfig {
     repeated PeerConfig peers = 3;
     int32 mtu = 4;
     int32 num_workers = 5;
+    bytes reserved = 6;
 }

proxy/wireguard/wireguard.go

@@ -85,6 +85,7 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
 			dialer:   dialer,
 			workers:  int(h.conf.NumWorkers),
 			dns:      h.dns,
+			reserved: h.conf.Reserved,
 		}
 
 		net, err := h.makeVirtualTun(bind)