support dest override in dns outbound

infra/conf/dns_proxy.go

@@ -2,11 +2,25 @@ package conf
 
 import (
 	"github.com/golang/protobuf/proto"
+	"v2ray.com/core/common/net"
 	"v2ray.com/core/proxy/dns"
 )
 
-type DnsOutboundConfig struct{}
+type DnsOutboundConfig struct {
+	Network Network  `json:network`
+	Address *Address `json:address`
+	Port    uint16   `json:port`
+}
 
 func (c *DnsOutboundConfig) Build() (proto.Message, error) {
-	return new(dns.Config), nil
+	config := &dns.Config{
+		Server: &net.Endpoint{
+			Network: c.Network.Build(),
+			Port:    uint32(c.Port),
+		},
+	}
+	if c.Address != nil {
+		config.Server.Address = c.Address.Build()
+	}
+	return config, nil
 }

infra/conf/dns_proxy_test.go

@@ -0,0 +1,33 @@
+package conf_test
+
+import (
+	"testing"
+
+	"v2ray.com/core/common/net"
+	. "v2ray.com/core/infra/conf"
+	"v2ray.com/core/proxy/dns"
+)
+
+func TestDnsProxyConfig(t *testing.T) {
+	creator := func() Buildable {
+		return new(DnsOutboundConfig)
+	}
+
+	runMultiTestCase(t, []TestCase{
+		{
+			Input: `{
+				"address": "8.8.8.8",
+				"port": 53,
+				"network": "tcp"
+			}`,
+			Parser: loadJSON(creator),
+			Output: &dns.Config{
+				Server: &net.Endpoint{
+					Network: net.Network_TCP,
+					Address: net.NewIPOrDomain(net.IPAddress([]byte{8, 8, 8, 8})),
+					Port:    53,
+				},
+			},
+		},
+	})
+}

infra/conf/v2ray_test.go

@@ -221,7 +221,9 @@ func TestV2RayConfig(t *testing.T) {
 								},
 							},
 						}),
-						ProxySettings: serial.ToTypedMessage(&dns_proxy.Config{}),
+						ProxySettings: serial.ToTypedMessage(&dns_proxy.Config{
+							Server: &net.Endpoint{},
+						}),
 					},
 				},
 				Inbound: []*core.InboundHandlerConfig{