DNS New Features: disableCache, finalQuery, unexpectedIPs, "*", UseSystem-queryStrategy, useSystemHosts

app/dns/config.proto

@@ -25,12 +25,16 @@ message NameServer {
   }
 
   repeated PriorityDomain prioritized_domain = 2;
-  repeated xray.app.router.GeoIP geoip = 3;
+  repeated xray.app.router.GeoIP expected_geoip = 3;
   repeated OriginalRule original_rules = 4;
   QueryStrategy query_strategy = 7;
-  bool allowUnexpectedIPs = 8;
+  bool actPrior = 8;
   string tag = 9;
   uint64 timeoutMs = 10;
+  bool disableCache = 11;
+  bool finalQuery = 12;
+  repeated xray.app.router.GeoIP unexpected_geoip = 13;
+  bool actUnprior = 14;
 }
 
 enum DomainMatchingType {
@@ -44,6 +48,7 @@ enum QueryStrategy {
   USE_IP = 0;
   USE_IP4 = 1;
   USE_IP6 = 2;
+  USE_SYS = 3;
 }
 
 message Config {

app/dns/dns.go

@@ -28,6 +28,7 @@ type DNS struct {
 	ctx                    context.Context
 	domainMatcher          strmatcher.IndexMatcher
 	matcherInfos           []*DomainMatcherInfo
+	checkSystem            bool
 }
 
 // DomainMatcherInfo contains information attached to index returned by Server.domainMatcher
@@ -47,13 +48,21 @@ func New(ctx context.Context, config *Config) (*DNS, error) {
 	}
 
 	var ipOption dns.IPOption
+	checkSystem := false
 	switch config.QueryStrategy {
 	case QueryStrategy_USE_IP:
 		ipOption = dns.IPOption{
 			IPv4Enable: true,
 			IPv6Enable: true,
 			FakeEnable: false,
 		}
+	case QueryStrategy_USE_SYS:
+		ipOption = dns.IPOption{
+			IPv4Enable: true,
+			IPv6Enable: true,
+			FakeEnable: false,
+		}
+		checkSystem = true
 	case QueryStrategy_USE_IP4:
 		ipOption = dns.IPOption{
 			IPv4Enable: true,
@@ -108,7 +117,7 @@ func New(ctx context.Context, config *Config) (*DNS, error) {
 			myClientIP = net.IP(ns.ClientIp)
 		}
 
-		disableCache := config.DisableCache
+		disableCache := config.DisableCache || ns.DisableCache
 
 		var tag = defaultTag
 		if len(ns.Tag) > 0 {
@@ -118,6 +127,7 @@ func New(ctx context.Context, config *Config) (*DNS, error) {
 		if !clientIPOption.IPv4Enable && !clientIPOption.IPv6Enable {
 			return nil, errors.New("no QueryStrategy available for ", ns.Address)
 		}
+
 		client, err := NewClient(ctx, ns, myClientIP, disableCache, tag, clientIPOption, &matcherInfos, updateDomain)
 		if err != nil {
 			return nil, errors.New("failed to create client").Base(err)
@@ -139,6 +149,7 @@ func New(ctx context.Context, config *Config) (*DNS, error) {
 		matcherInfos:           matcherInfos,
 		disableFallback:        config.DisableFallback,
 		disableFallbackIfMatch: config.DisableFallbackIfMatch,
+		checkSystem:            checkSystem,
 	}, nil
 }
 
@@ -179,8 +190,14 @@ func (s *DNS) LookupIP(domain string, option dns.IPOption) ([]net.IP, uint32, er
 		return nil, 0, errors.New("empty domain name")
 	}
 
-	option.IPv4Enable = option.IPv4Enable && s.ipOption.IPv4Enable
-	option.IPv6Enable = option.IPv6Enable && s.ipOption.IPv6Enable
+	if s.checkSystem {
+		supportIPv4, supportIPv6 := checkSystemNetwork()
+		option.IPv4Enable = option.IPv4Enable && supportIPv4
+		option.IPv6Enable = option.IPv6Enable && supportIPv6
+	} else {
+		option.IPv4Enable = option.IPv4Enable && s.ipOption.IPv4Enable
+		option.IPv6Enable = option.IPv6Enable && s.ipOption.IPv6Enable
+	}
 
 	if !option.IPv4Enable && !option.IPv6Enable {
 		return nil, 0, dns.ErrEmptyResponse
@@ -227,6 +244,9 @@ func (s *DNS) LookupIP(domain string, option dns.IPOption) ([]net.IP, uint32, er
 		}
 		errs = append(errs, err)
 
+		if client.IsFinalQuery() {
+			break
+		}
 	}
 
 	if len(errs) > 0 {
@@ -318,3 +338,22 @@ func init() {
 		return New(ctx, config.(*Config))
 	}))
 }
+
+func checkSystemNetwork() (supportIPv4 bool, supportIPv6 bool) {
+	conn4, err4 := net.Dial("udp4", "8.8.8.8:53")
+	if err4 != nil {
+		supportIPv4 = false
+	} else {
+		supportIPv4 = true
+		conn4.Close()
+	}
+
+	conn6, err6 := net.Dial("udp6", "[2001:4860:4860::8888]:53")
+	if err6 != nil {
+		supportIPv6 = false
+	} else {
+		supportIPv6 = true
+		conn6.Close()
+	}
+	return
+}

app/dns/dns_test.go

@@ -539,7 +539,7 @@ func TestIPMatch(t *testing.T) {
 							},
 							Port: uint32(port),
 						},
-						Geoip: []*router.GeoIP{
+						ExpectedGeoip: []*router.GeoIP{
 							{
 								CountryCode: "local",
 								Cidr: []*router.CIDR{
@@ -563,7 +563,7 @@ func TestIPMatch(t *testing.T) {
 							},
 							Port: uint32(port),
 						},
-						Geoip: []*router.GeoIP{
+						ExpectedGeoip: []*router.GeoIP{
 							{
 								CountryCode: "test",
 								Cidr: []*router.CIDR{
@@ -667,7 +667,7 @@ func TestLocalDomain(t *testing.T) {
 							// Equivalent of dotless:localhost
 							{Type: DomainMatchingType_Regex, Domain: "^[^.]*localhost[^.]*$"},
 						},
-						Geoip: []*router.GeoIP{
+						ExpectedGeoip: []*router.GeoIP{
 							{ // Will match localhost, localhost-a and localhost-b,
 								CountryCode: "local",
 								Cidr: []*router.CIDR{
@@ -897,7 +897,7 @@ func TestMultiMatchPrioritizedDomain(t *testing.T) {
 								Domain: "google.com",
 							},
 						},
-						Geoip: []*router.GeoIP{
+						ExpectedGeoip: []*router.GeoIP{
 							{ // Will only match 8.8.8.8 and 8.8.4.4
 								Cidr: []*router.CIDR{
 									{Ip: []byte{8, 8, 8, 8}, Prefix: 32},
@@ -922,7 +922,7 @@ func TestMultiMatchPrioritizedDomain(t *testing.T) {
 								Domain: "google.com",
 							},
 						},
-						Geoip: []*router.GeoIP{
+						ExpectedGeoip: []*router.GeoIP{
 							{ // Will match 8.8.8.8 and 8.8.8.7, etc
 								Cidr: []*router.CIDR{
 									{Ip: []byte{8, 8, 8, 7}, Prefix: 24},
@@ -946,7 +946,7 @@ func TestMultiMatchPrioritizedDomain(t *testing.T) {
 								Domain: "api.google.com",
 							},
 						},
-						Geoip: []*router.GeoIP{
+						ExpectedGeoip: []*router.GeoIP{
 							{ // Will only match 8.8.7.7 (api.google.com)
 								Cidr: []*router.CIDR{
 									{Ip: []byte{8, 8, 7, 7}, Prefix: 32},
@@ -970,7 +970,7 @@ func TestMultiMatchPrioritizedDomain(t *testing.T) {
 								Domain: "v2.api.google.com",
 							},
 						},
-						Geoip: []*router.GeoIP{
+						ExpectedGeoip: []*router.GeoIP{
 							{ // Will only match 8.8.7.8 (v2.api.google.com)
 								Cidr: []*router.CIDR{
 									{Ip: []byte{8, 8, 7, 8}, Prefix: 32},

app/dns/nameserver.go

@@ -26,14 +26,18 @@ type Server interface {
 
 // Client is the interface for DNS client.
 type Client struct {
-	server             Server
-	skipFallback       bool
-	domains            []string
-	expectedIPs        []*router.GeoIPMatcher
-	allowUnexpectedIPs bool
-	tag                string
-	timeoutMs          time.Duration
-	ipOption           *dns.IPOption
+	server        Server
+	skipFallback  bool
+	domains       []string
+	expectedIPs   []*router.GeoIPMatcher
+	unexpectedIPs []*router.GeoIPMatcher
+	actPrior      bool
+	actUnprior    bool
+	tag           string
+	timeoutMs     time.Duration
+	finalQuery    bool
+	ipOption      *dns.IPOption
+	checkSystem   bool
 }
 
 // NewServer creates a name server object according to the network destination url.
@@ -150,13 +154,23 @@ func NewClient(
 		}
 
 		// Establish expected IPs
-		var matchers []*router.GeoIPMatcher
-		for _, geoip := range ns.Geoip {
+		var expectedMatchers []*router.GeoIPMatcher
+		for _, geoip := range ns.ExpectedGeoip {
 			matcher, err := router.GlobalGeoIPContainer.Add(geoip)
 			if err != nil {
-				return errors.New("failed to create ip matcher").Base(err).AtWarning()
+				return errors.New("failed to create expected ip matcher").Base(err).AtWarning()
 			}
-			matchers = append(matchers, matcher)
+			expectedMatchers = append(expectedMatchers, matcher)
+		}
+
+		// Establish unexpected IPs
+		var unexpectedMatchers []*router.GeoIPMatcher
+		for _, geoip := range ns.UnexpectedGeoip {
+			matcher, err := router.GlobalGeoIPContainer.Add(geoip)
+			if err != nil {
+				return errors.New("failed to create unexpected ip matcher").Base(err).AtWarning()
+			}
+			unexpectedMatchers = append(unexpectedMatchers, matcher)
 		}
 
 		if len(clientIP) > 0 {
@@ -173,14 +187,20 @@ func NewClient(
 			timeoutMs = time.Duration(ns.TimeoutMs) * time.Millisecond
 		}
 
+		checkSystem := ns.QueryStrategy == QueryStrategy_USE_SYS
+
 		client.server = server
 		client.skipFallback = ns.SkipFallback
 		client.domains = rules
-		client.expectedIPs = matchers
-		client.allowUnexpectedIPs = ns.AllowUnexpectedIPs
+		client.expectedIPs = expectedMatchers
+		client.unexpectedIPs = unexpectedMatchers
+		client.actPrior = ns.ActPrior
+		client.actUnprior = ns.ActUnprior
 		client.tag = tag
 		client.timeoutMs = timeoutMs
+		client.finalQuery = ns.FinalQuery
 		client.ipOption = &ipOption
+		client.checkSystem = checkSystem
 		return nil
 	})
 	return client, err
@@ -191,10 +211,21 @@ func (c *Client) Name() string {
 	return c.server.Name()
 }
 
+func (c *Client) IsFinalQuery() bool {
+	return c.finalQuery
+}
+
 // QueryIP sends DNS query to the name server with the client's IP.
 func (c *Client) QueryIP(ctx context.Context, domain string, option dns.IPOption) ([]net.IP, uint32, error) {
-	option.IPv4Enable = option.IPv4Enable && c.ipOption.IPv4Enable
-	option.IPv6Enable = option.IPv6Enable && c.ipOption.IPv6Enable
+	if c.checkSystem {
+		supportIPv4, supportIPv6 := checkSystemNetwork()
+		option.IPv4Enable = option.IPv4Enable && supportIPv4
+		option.IPv6Enable = option.IPv6Enable && supportIPv6
+	} else {
+		option.IPv4Enable = option.IPv4Enable && c.ipOption.IPv4Enable
+		option.IPv6Enable = option.IPv6Enable && c.ipOption.IPv6Enable
+	}
+
 	if !option.IPv4Enable && !option.IPv6Enable {
 		return nil, 0, dns.ErrEmptyResponse
 	}
@@ -212,39 +243,47 @@ func (c *Client) QueryIP(ctx context.Context, domain string, option dns.IPOption
 		return nil, 0, dns.ErrEmptyResponse
 	}
 
-	if len(c.expectedIPs) > 0 {
-		newIps := c.MatchExpectedIPs(domain, ips)
-		if len(newIps) == 0 {
-			if !c.allowUnexpectedIPs {
-				return nil, 0, dns.ErrEmptyResponse
-			}
-		} else {
-			ips = newIps
+	if len(c.expectedIPs) > 0 && !c.actPrior {
+		ips = router.MatchIPs(c.expectedIPs, ips, false)
+		errors.LogDebug(context.Background(), "domain ", domain, " expectedIPs ", ips, " matched at server ", c.Name())
+		if len(ips) == 0 {
+			return nil, 0, dns.ErrEmptyResponse
 		}
 	}
 
-	return ips, ttl, nil
-}
+	if len(c.unexpectedIPs) > 0 && !c.actUnprior {
+		ips = router.MatchIPs(c.unexpectedIPs, ips, true)
+		errors.LogDebug(context.Background(), "domain ", domain, " unexpectedIPs ", ips, " matched at server ", c.Name())
+		if len(ips) == 0 {
+			return nil, 0, dns.ErrEmptyResponse
+		}
+	}
 
-// MatchExpectedIPs matches queried domain IPs with expected IPs and returns matched ones.
-func (c *Client) MatchExpectedIPs(domain string, ips []net.IP) []net.IP {
-	var newIps []net.IP
-	for _, ip := range ips {
-		for _, matcher := range c.expectedIPs {
-			if matcher.Match(ip) {
-				newIps = append(newIps, ip)
-				break
-			}
+	if len(c.expectedIPs) > 0 && c.actPrior {
+		ipsNew := router.MatchIPs(c.expectedIPs, ips, false)
+		if len(ipsNew) > 0 {
+			ips = ipsNew
+			errors.LogDebug(context.Background(), "domain ", domain, " priorIPs ", ips, " matched at server ", c.Name())
 		}
 	}
-	errors.LogDebug(context.Background(), "domain ", domain, " expectedIPs ", newIps, " matched at server ", c.Name())
-	return newIps
+
+	if len(c.unexpectedIPs) > 0 && c.actUnprior {
+		ipsNew := router.MatchIPs(c.unexpectedIPs, ips, true)
+		if len(ipsNew) > 0 {
+			ips = ipsNew
+			errors.LogDebug(context.Background(), "domain ", domain, " unpriorIPs ", ips, " matched at server ", c.Name())
+		}
+	}
+
+	return ips, ttl, nil
 }
 
 func ResolveIpOptionOverride(queryStrategy QueryStrategy, ipOption dns.IPOption) dns.IPOption {
 	switch queryStrategy {
 	case QueryStrategy_USE_IP:
 		return ipOption
+	case QueryStrategy_USE_SYS:
+		return ipOption
 	case QueryStrategy_USE_IP4:
 		return dns.IPOption{
 			IPv4Enable: ipOption.IPv4Enable,

app/router/condition_geoip.go

@@ -116,3 +116,29 @@ func (c *GeoIPMatcherContainer) Add(geoip *GeoIP) (*GeoIPMatcher, error) {
 }
 
 var GlobalGeoIPContainer GeoIPMatcherContainer
+
+func MatchIPs(matchers []*GeoIPMatcher, ips []net.IP, reverse bool) []net.IP {
+	if len(matchers) == 0 {
+		panic("GeoIP matchers should not be empty to avoid ambiguity")
+	}
+	newIPs := make([]net.IP, 0, len(ips))
+	var isFound bool
+	for _, ip := range ips {
+		isFound = false
+		for _, matcher := range matchers {
+			if matcher.Match(ip) {
+				isFound = true
+				break
+			}
+		}
+		if isFound && !reverse {
+			newIPs = append(newIPs, ip)
+			continue
+		}
+		if !isFound && reverse {
+			newIPs = append(newIPs, ip)
+			continue
+		}
+	}
+	return newIPs
+}