统一 `domainStrategy` 行为. (#2720)

* 统一 `domainStrategy` 行为.

* Update proto

---------

Co-authored-by: rui0572 <125641819+rui0572@users.noreply.github.com>

infra/conf/transport_internet.go

@@ -654,12 +654,30 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 
 	dStrategy := internet.DomainStrategy_AS_IS
 	switch strings.ToLower(c.DomainStrategy) {
-	case "useip", "use_ip":
+	case "asis", "":
+		dStrategy = internet.DomainStrategy_AS_IS
+	case "useip":
 		dStrategy = internet.DomainStrategy_USE_IP
-	case "useip4", "useipv4", "use_ipv4", "use_ip_v4", "use_ip4":
+	case "useipv4":
 		dStrategy = internet.DomainStrategy_USE_IP4
-	case "useip6", "useipv6", "use_ipv6", "use_ip_v6", "use_ip6":
+	case "useipv6":
 		dStrategy = internet.DomainStrategy_USE_IP6
+	case "useipv4v6":
+		dStrategy = internet.DomainStrategy_USE_IP46
+	case "useipv6v4":
+		dStrategy = internet.DomainStrategy_USE_IP64
+	case "forceip":
+		dStrategy = internet.DomainStrategy_FORCE_IP
+	case "forceipv4":
+		dStrategy = internet.DomainStrategy_FORCE_IP4
+	case "forceipv6":
+		dStrategy = internet.DomainStrategy_FORCE_IP6
+	case "forceipv4v6":
+		dStrategy = internet.DomainStrategy_FORCE_IP46
+	case "forceipv6v4":
+		dStrategy = internet.DomainStrategy_FORCE_IP64
+	default:
+		return nil, newError("unsupported domain strategy: ", c.DomainStrategy)
 	}
 
 	return &internet.SocketConfig{

transport/internet/config.go

@@ -12,6 +12,21 @@ var (
 	globalTransportSettings           []*TransportConfig
 )
 
+var strategy = [][]byte{
+	//              name        strategy,   prefer, fallback
+	{0, 0, 0}, //   AsIs        none,       /,      /
+	{1, 0, 0}, //   UseIP       use,        both,   none
+	{1, 4, 0}, //   UseIPv4     use,        4,      none
+	{1, 6, 0}, //   UseIPv6     use,        6,      none
+	{1, 4, 6}, //   UseIPv4v6   use,        4,      6
+	{1, 6, 4}, //   UseIPv6v4   use,        6,      4
+	{2, 0, 0}, //   ForceIP     force,      both,   none
+	{2, 4, 0}, //   ForceIPv4   force,      4,      none
+	{2, 6, 0}, //   ForceIPv6   force,      6,      none
+	{2, 4, 6}, //   ForceIPv4v6 force,      4,      6
+	{2, 6, 4}, //   ForceIPv6v4 force,      6,      4
+}
+
 const unknownProtocol = "unknown"
 
 func transportProtocolToString(protocol TransportProtocol) string {
@@ -122,3 +137,31 @@ func (c *ProxyConfig) HasTag() bool {
 func (m SocketConfig_TProxyMode) IsEnabled() bool {
 	return m != SocketConfig_Off
 }
+
+func (s DomainStrategy) hasStrategy() bool {
+	return strategy[s][0] != 0
+}
+
+func (s DomainStrategy) forceIP() bool {
+	return strategy[s][0] == 2
+}
+
+func (s DomainStrategy) preferIP4() bool {
+	return strategy[s][1] == 4 || strategy[s][1] == 0
+}
+
+func (s DomainStrategy) preferIP6() bool {
+	return strategy[s][1] == 6 || strategy[s][1] == 0
+}
+
+func (s DomainStrategy) hasFallback() bool {
+	return strategy[s][2] != 0
+}
+
+func (s DomainStrategy) fallbackIP4() bool {
+	return strategy[s][2] == 4
+}
+
+func (s DomainStrategy) fallbackIP6() bool {
+	return strategy[s][2] == 6
+}

transport/internet/config.pb.go

@@ -86,6 +86,13 @@ const (
 	DomainStrategy_USE_IP     DomainStrategy = 1
 	DomainStrategy_USE_IP4    DomainStrategy = 2
 	DomainStrategy_USE_IP6    DomainStrategy = 3
+	DomainStrategy_USE_IP46   DomainStrategy = 4
+	DomainStrategy_USE_IP64   DomainStrategy = 5
+	DomainStrategy_FORCE_IP   DomainStrategy = 6
+	DomainStrategy_FORCE_IP4  DomainStrategy = 7
+	DomainStrategy_FORCE_IP6  DomainStrategy = 8
+	DomainStrategy_FORCE_IP46 DomainStrategy = 9
+	DomainStrategy_FORCE_IP64 DomainStrategy = 10
 )
 
 // Enum value maps for DomainStrategy.
@@ -95,12 +102,26 @@ var (
 		1:  "USE_IP",
 		2:  "USE_IP4",
 		3:  "USE_IP6",
+		4:  "USE_IP46",
+		5:  "USE_IP64",
+		6:  "FORCE_IP",
+		7:  "FORCE_IP4",
+		8:  "FORCE_IP6",
+		9:  "FORCE_IP46",
+		10: "FORCE_IP64",
 	}
 	DomainStrategy_value = map[string]int32{
 		"AS_IS":      0,
 		"USE_IP":     1,
 		"USE_IP4":    2,
 		"USE_IP6":    3,
+		"USE_IP46":   4,
+		"USE_IP64":   5,
+		"FORCE_IP":   6,
+		"FORCE_IP4":  7,
+		"FORCE_IP6":  8,
+		"FORCE_IP46": 9,
+		"FORCE_IP64": 10,
 	}
 )
 
@@ -710,18 +731,24 @@ var file_transport_internet_config_proto_rawDesc = []byte{
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 }
 
 var (

transport/internet/config.proto

@@ -22,6 +22,13 @@ enum DomainStrategy {
   USE_IP = 1;
   USE_IP4 = 2;
   USE_IP6 = 3;
+  USE_IP46 = 4;
+  USE_IP64 = 5;
+  FORCE_IP = 6;
+  FORCE_IP4 = 7;
+  FORCE_IP6 = 8;
+  FORCE_IP46 = 9;
+  FORCE_IP64 = 10;
 }
 
 message TransportConfig {

transport/internet/dialer.go

@@ -78,37 +78,27 @@ func lookupIP(domain string, strategy DomainStrategy, localAddr net.Address) ([]
 		return nil, nil
 	}
 
-	option := dns.IPOption{
+	ips, err := dnsClient.LookupIP(domain, dns.IPOption{
-		IPv4Enable: true,
+		IPv4Enable: (localAddr == nil || localAddr.Family().IsIPv4()) && strategy.preferIP4(),
-		IPv6Enable: true,
+		IPv6Enable: (localAddr == nil || localAddr.Family().IsIPv6()) && strategy.preferIP6(),
-		FakeEnable: false,
+	})
+	{ // Resolve fallback
+		if (len(ips) == 0 || err != nil) && strategy.hasFallback() && localAddr == nil {
+			ips, err = dnsClient.LookupIP(domain, dns.IPOption{
+				IPv4Enable: strategy.fallbackIP4(),
+				IPv6Enable: strategy.fallbackIP6(),
+			})
+		}
 	}
 
-	switch {
+	return ips, err
-	case strategy == DomainStrategy_USE_IP4 || (localAddr != nil && localAddr.Family().IsIPv4()):
-		option = dns.IPOption{
-			IPv4Enable: true,
-			IPv6Enable: false,
-			FakeEnable: false,
-		}
-	case strategy == DomainStrategy_USE_IP6 || (localAddr != nil && localAddr.Family().IsIPv6()):
-		option = dns.IPOption{
-			IPv4Enable: false,
-			IPv6Enable: true,
-			FakeEnable: false,
-		}
-	case strategy == DomainStrategy_AS_IS:
-		return nil, nil
-	}
-
-	return dnsClient.LookupIP(domain, option)
 }
 
 func canLookupIP(ctx context.Context, dst net.Destination, sockopt *SocketConfig) bool {
 	if dst.Address.Family().IsIP() || dnsClient == nil {
 		return false
 	}
-	return sockopt.DomainStrategy != DomainStrategy_AS_IS
+	return sockopt.DomainStrategy.hasStrategy()
 }
 
 func redirect(ctx context.Context, dst net.Destination, obt string) net.Conn {