fix: set default interface values for proxy servers

Author: mrhaoxx

tunnels/wireguard/tcp/tcp.go

@@ -43,7 +43,7 @@ type Config struct {
 	KeepaliveCount    int
 	Tnet              *netstack.Net
 	StackLock         *sync.Mutex
-	Underlying        net.Interface
+	// Underlying        net.Interface
 
 	Addr tcpip.Address
 }
@@ -128,7 +128,7 @@ func checkDst(config *Config, s stack.TransportEndpointID) (net.Conn, bool) {
 
 	ctx, cancel := context.WithTimeout(context.Background(), config.ConnTimeout)
 	defer cancel()
-	c, err := config.Underlying.DialContext(ctx, "tcp", gnet.JoinHostPort(s.LocalAddress.String(), fmt.Sprint(s.LocalPort)))
+	c, err := net.DefaultRouteTable.DialContext(ctx, "tcp", gnet.JoinHostPort(s.LocalAddress.String(), fmt.Sprint(s.LocalPort)))
 
 	// c, err := gonet.DialTCPWithBind(ctx, config.Tnet.Stack(), tcpip.FullAddress{
 	// 	NIC:  1,

tunnels/wireguard/udp/udp.go

@@ -53,6 +53,8 @@ var connMapLock = sync.RWMutex{}
 type Config struct {
 	Tnet      *netstack.Net
 	StackLock *sync.Mutex
+
+	Underlying net.Interface
 }
 
 // Handler handles UDP packets. Returns function that returns true if packet is handled, or false if ICMP Destination Unreachable should be sent.

ui/builtin.go

@@ -632,8 +632,13 @@ var _builtin_refs_assertions = map[string]Assert{
 		},
 	},
 	"builtin::http::forwardproxier": {
-		Type: "null",
-		Desc: "HTTP forward proxy implementation (no configuration needed)",
+		Type: "map",
+		Sub: AssertMap{
+			"interface": {
+				Type:    "ptr",
+				Default: &net.SysInterface{},
+			},
+		},
 	},
 	"builtin::http::acme::fileprovider": {
 		Type: "map",
@@ -946,8 +951,8 @@ var _builtin_refs_assertions = map[string]Assert{
 				},
 			},
 			"interface": {
-				Type:     "ptr",
-				Required: false,
+				Type:    "ptr",
+				Default: &net.SysInterface{},
 			},
 		},
 	},
@@ -1442,7 +1447,10 @@ var _builtin_refs = map[string]Inst{
 		return Dns, nil
 	},
 	"builtin::http::forwardproxier": func(spec *ArgNode) (any, error) {
-		return &thttp.StdForwardProxy{}, nil
+
+		underlying := spec.MustGet("interface").Value.(net.Interface)
+
+		return &thttp.StdForwardProxy{Underlying: underlying}, nil
 	},
 	// "builtin::http::fwdforwardproxier": func(spec *ArgNode) (any, error) {
 	// 	proxyurl := spec.MustGet("ProxyURL").ToString()