Add support for client-subnet DNS options

route/router.go

@@ -222,7 +222,20 @@ func NewRouter(
 					return nil, E.New("parse dns server[", tag, "]: missing address_resolver")
 				}
 			}
-			transport, err := dns.CreateTransport(tag, ctx, logFactory.NewLogger(F.ToString("dns/transport[", tag, "]")), detour, server.Address)
+			var clientSubnet netip.Addr
+			if server.ClientSubnet != nil {
+				clientSubnet = server.ClientSubnet.Build()
+			} else if dnsOptions.ClientSubnet != nil {
+				clientSubnet = dnsOptions.ClientSubnet.Build()
+			}
+			transport, err := dns.CreateTransport(dns.TransportOptions{
+				Context:      ctx,
+				Logger:       logFactory.NewLogger(F.ToString("dns/transport[", tag, "]")),
+				Name:         tag,
+				Dialer:       detour,
+				Address:      server.Address,
+				ClientSubnet: clientSubnet,
+			})
 			if err != nil {
 				return nil, E.Cause(err, "parse dns server[", tag, "]")
 			}
@@ -262,7 +275,11 @@ func NewRouter(
 	}
 	if defaultTransport == nil {
 		if len(transports) == 0 {
-			transports = append(transports, dns.NewLocalTransport("local", N.SystemDialer))
+			transports = append(transports, common.Must1(dns.CreateTransport(dns.TransportOptions{
+				Context: ctx,
+				Name:    "local",
+				Dialer:  common.Must1(dialer.NewDefault(router, option.DialerOptions{})),
+			})))
 		}
 		defaultTransport = transports[0]
 	}