Refactor: MainResolver

adapter/outbound/direct.go

@@ -14,6 +14,7 @@ type Direct struct {
 
 // DialContext implements C.ProxyAdapter
 func (d *Direct) DialContext(ctx context.Context, metadata *C.Metadata, opts ...dialer.Option) (C.Conn, error) {
+	opts = append(opts, dialer.WithDirect())
 	c, err := dialer.DialContext(ctx, "tcp", metadata.RemoteAddress(), d.Base.DialOptions(opts...)...)
 	if err != nil {
 		return nil, err
@@ -24,6 +25,7 @@ func (d *Direct) DialContext(ctx context.Context, metadata *C.Metadata, opts ...
 
 // ListenPacketContext implements C.ProxyAdapter
 func (d *Direct) ListenPacketContext(ctx context.Context, metadata *C.Metadata, opts ...dialer.Option) (C.PacketConn, error) {
+	opts = append(opts, dialer.WithDirect())
 	pc, err := dialer.ListenPacket(ctx, "udp", "", d.Base.DialOptions(opts...)...)
 	if err != nil {
 		return nil, err

adapter/outbound/util.go

@@ -44,7 +44,7 @@ func resolveUDPAddr(network, address string) (*net.UDPAddr, error) {
 		return nil, err
 	}
 
-	ip, err := resolver.ResolveIP(host)
+	ip, err := resolver.ResolveProxyServerHost(host)
 	if err != nil {
 		return nil, err
 	}

component/dialer/dialer.go

@@ -32,14 +32,14 @@ func DialContext(ctx context.Context, network, address string, options ...Option
 		var ip net.IP
 		switch network {
 		case "tcp4", "udp4":
-			if opt.interfaceName != "" {
+			if !opt.direct {
-				ip, err = resolver.ResolveIPv4WithMain(host)
+				ip, err = resolver.ResolveIPv4ProxyServerHost(host)
 			} else {
 				ip, err = resolver.ResolveIPv4(host)
 			}
 		default:
-			if opt.interfaceName != "" {
+			if !opt.direct {
-				ip, err = resolver.ResolveIPv6WithMain(host)
+				ip, err = resolver.ResolveIPv6ProxyServerHost(host)
 			} else {
 				ip, err = resolver.ResolveIPv6(host)
 			}
@@ -121,7 +121,7 @@ func dualStackDialContext(ctx context.Context, network, address string, opt *opt
 	results := make(chan dialResult)
 	var primary, fallback dialResult
 
-	startRacer := func(ctx context.Context, network, host string, ipv6 bool) {
+	startRacer := func(ctx context.Context, network, host string, direct bool, ipv6 bool) {
 		result := dialResult{ipv6: ipv6, done: true}
 		defer func() {
 			select {
@@ -135,14 +135,14 @@ func dualStackDialContext(ctx context.Context, network, address string, opt *opt
 
 		var ip net.IP
 		if ipv6 {
-			if opt.interfaceName != "" {
+			if !direct {
-				ip, result.error = resolver.ResolveIPv6WithMain(host)
+				ip, result.error = resolver.ResolveIPv6ProxyServerHost(host)
 			} else {
 				ip, result.error = resolver.ResolveIPv6(host)
 			}
 		} else {
-			if opt.interfaceName != "" {
+			if !direct {
-				ip, result.error = resolver.ResolveIPv4WithMain(host)
+				ip, result.error = resolver.ResolveIPv4ProxyServerHost(host)
 			} else {
 				ip, result.error = resolver.ResolveIPv4(host)
 			}
@@ -155,8 +155,8 @@ func dualStackDialContext(ctx context.Context, network, address string, opt *opt
 		result.Conn, result.error = dialContext(ctx, network, ip, port, opt)
 	}
 
-	go startRacer(ctx, network+"4", host, false)
+	go startRacer(ctx, network+"4", host, opt.direct, false)
-	go startRacer(ctx, network+"6", host, true)
+	go startRacer(ctx, network+"6", host, opt.direct, true)
 
 	for res := range results {
 		if res.error == nil {

component/dialer/options.go

@@ -12,6 +12,7 @@ type option struct {
 	interfaceName string
 	addrReuse     bool
 	routingMark   int
+	direct        bool
 }
 
 type Option func(opt *option)
@@ -33,3 +34,9 @@ func WithRoutingMark(mark int) Option {
 		opt.routingMark = mark
 	}
 }
+
+func WithDirect() Option {
+	return func(opt *option) {
+		opt.direct = true
+	}
+}

component/resolver/resolver.go

@@ -15,8 +15,8 @@ var (
 	// DefaultResolver aim to resolve ip
 	DefaultResolver Resolver
 
-	// MainResolver resolve ip with main domain server
+	// ProxyServerHostResolver resolve ip to proxies server host
-	MainResolver Resolver
+	ProxyServerHostResolver Resolver
 
 	// DisableIPv6 means don't resolve ipv6 host
 	// default value is true
@@ -46,10 +46,6 @@ func ResolveIPv4(host string) (net.IP, error) {
 	return ResolveIPv4WithResolver(host, DefaultResolver)
 }
 
-func ResolveIPv4WithMain(host string) (net.IP, error) {
-	return ResolveIPv4WithResolver(host, MainResolver)
-}
-
 func ResolveIPv4WithResolver(host string, r Resolver) (net.IP, error) {
 	if node := DefaultHosts.Search(host); node != nil {
 		if ip := node.Data.(net.IP).To4(); ip != nil {
@@ -69,6 +65,7 @@ func ResolveIPv4WithResolver(host string, r Resolver) (net.IP, error) {
 		return r.ResolveIPv4(host)
 	}
 
+	if DefaultResolver == nil {
 		ctx, cancel := context.WithTimeout(context.Background(), DefaultDNSTimeout)
 		defer cancel()
 		ipAddrs, err := net.DefaultResolver.LookupIP(ctx, "ip4", host)
@@ -79,6 +76,9 @@ func ResolveIPv4WithResolver(host string, r Resolver) (net.IP, error) {
 		}
 
 		return ipAddrs[rand.Intn(len(ipAddrs))], nil
+	}
+
+	return nil, ErrIPNotFound
 }
 
 // ResolveIPv6 with a host, return ipv6
@@ -86,10 +86,6 @@ func ResolveIPv6(host string) (net.IP, error) {
 	return ResolveIPv6WithResolver(host, DefaultResolver)
 }
 
-func ResolveIPv6WithMain(host string) (net.IP, error) {
-	return ResolveIPv6WithResolver(host, MainResolver)
-}
-
 func ResolveIPv6WithResolver(host string, r Resolver) (net.IP, error) {
 	if DisableIPv6 {
 		return nil, ErrIPv6Disabled
@@ -113,6 +109,7 @@ func ResolveIPv6WithResolver(host string, r Resolver) (net.IP, error) {
 		return r.ResolveIPv6(host)
 	}
 
+	if DefaultResolver == nil {
 		ctx, cancel := context.WithTimeout(context.Background(), DefaultDNSTimeout)
 		defer cancel()
 		ipAddrs, err := net.DefaultResolver.LookupIP(ctx, "ip6", host)
@@ -123,6 +120,9 @@ func ResolveIPv6WithResolver(host string, r Resolver) (net.IP, error) {
 		}
 
 		return ipAddrs[rand.Intn(len(ipAddrs))], nil
+	}
+
+	return nil, ErrIPNotFound
 }
 
 // ResolveIPWithResolver same as ResolveIP, but with a resolver
@@ -145,12 +145,16 @@ func ResolveIPWithResolver(host string, r Resolver) (net.IP, error) {
 		return ip, nil
 	}
 
+	if DefaultResolver == nil {
 		ipAddr, err := net.ResolveIPAddr("ip", host)
 		if err != nil {
 			return nil, err
 		}
 
 		return ipAddr.IP, nil
+	}
+
+	return nil, ErrIPNotFound
 }
 
 // ResolveIP with a host, return ip
@@ -158,7 +162,26 @@ func ResolveIP(host string) (net.IP, error) {
 	return ResolveIPWithResolver(host, DefaultResolver)
 }
 
-// ResolveIPWithMainResolver with a host, use main resolver, return ip
+// ResolveIPv4ProxyServerHost proxies server host only
-func ResolveIPWithMainResolver(host string) (net.IP, error) {
+func ResolveIPv4ProxyServerHost(host string) (net.IP, error) {
-	return ResolveIPWithResolver(host, MainResolver)
+	if ProxyServerHostResolver != nil {
+		return ResolveIPv4WithResolver(host, ProxyServerHostResolver)
+	}
+	return ResolveIPv4(host)
+}
+
+// ResolveIPv6ProxyServerHost proxies server host only
+func ResolveIPv6ProxyServerHost(host string) (net.IP, error) {
+	if ProxyServerHostResolver != nil {
+		return ResolveIPv6WithResolver(host, ProxyServerHostResolver)
+	}
+	return ResolveIPv6(host)
+}
+
+// ResolveProxyServerHost proxies server host only
+func ResolveProxyServerHost(host string) (net.IP, error) {
+	if ProxyServerHostResolver != nil {
+		return ResolveIPWithResolver(host, ProxyServerHostResolver)
+	}
+	return ResolveIP(host)
 }

config/config.go

@@ -74,6 +74,7 @@ type DNS struct {
 	FakeIPRange           *fakeip.Pool
 	Hosts                 *trie.DomainTrie
 	NameServerPolicy      map[string]dns.NameServer
+	ProxyServerNameserver []dns.NameServer
 }
 
 // FallbackFilter config
@@ -137,6 +138,7 @@ type RawDNS struct {
 	FakeIPFilter          []string          `yaml:"fake-ip-filter"`
 	DefaultNameserver     []string          `yaml:"default-nameserver"`
 	NameServerPolicy      map[string]string `yaml:"nameserver-policy"`
+	ProxyServerNameserver []string          `yaml:"proxy-server-nameserver"`
 }
 
 type RawFallbackFilter struct {
@@ -679,6 +681,10 @@ func parseDNS(rawCfg *RawConfig, hosts *trie.DomainTrie, rules []C.Rule) (*DNS,
 		return nil, err
 	}
 
+	if dnsCfg.ProxyServerNameserver, err = parseNameServer(cfg.ProxyServerNameserver); err != nil {
+		return nil, err
+	}
+
 	if len(cfg.DefaultNameserver) == 0 {
 		return nil, errors.New("default nameserver should have at least one nameserver")
 	}

dns/resolver.go

@@ -41,6 +41,7 @@ type Resolver struct {
 	group                 singleflight.Group
 	lruCache              *cache.LruCache
 	policy                *trie.DomainTrie
+	proxyServer           []dnsClient
 }
 
 // ResolveIP request with TypeA and TypeAAAA, priority return TypeA
@@ -301,6 +302,11 @@ func (r *Resolver) asyncExchange(ctx context.Context, client []dnsClient, msg *D
 	return ch
 }
 
+// HasProxyServer has proxy server dns client
+func (r *Resolver) HasProxyServer() bool {
+	return len(r.main) > 0
+}
+
 type NameServer struct {
 	Net          string
 	Addr         string
@@ -319,6 +325,7 @@ type FallbackFilter struct {
 type Config struct {
 	Main, Fallback []NameServer
 	Default        []NameServer
+	ProxyServer    []NameServer
 	IPv6           bool
 	EnhancedMode   C.DNSMode
 	FallbackFilter FallbackFilter
@@ -344,6 +351,10 @@ func NewResolver(config Config) *Resolver {
 		r.fallback = transform(config.Fallback, defaultResolver)
 	}
 
+	if len(config.ProxyServer) != 0 {
+		r.proxyServer = transform(config.ProxyServer, defaultResolver)
+	}
+
 	if len(config.Policy) != 0 {
 		r.policy = trie.New()
 		for domain, nameserver := range config.Policy {
@@ -377,10 +388,10 @@ func NewResolver(config Config) *Resolver {
 	return r
 }
 
-func NewMainResolver(old *Resolver) *Resolver {
+func NewProxyServerHostResolver(old *Resolver) *Resolver {
 	r := &Resolver{
 		ipv6:     old.ipv6,
-		main:     old.main,
+		main:     old.proxyServer,
 		lruCache: old.lruCache,
 		hosts:    old.hosts,
 		policy:   old.policy,

hub/executor/executor.go

@@ -132,10 +132,11 @@ func updateDNS(c *config.DNS, t *config.Tun) {
 		},
 		Default:     c.DefaultNameserver,
 		Policy:      c.NameServerPolicy,
+		ProxyServer: c.ProxyServerNameserver,
 	}
 
 	r := dns.NewResolver(cfg)
-	mr := dns.NewMainResolver(r)
+	pr := dns.NewProxyServerHostResolver(r)
 	m := dns.NewEnhancer(cfg)
 
 	// reuse cache of old host mapper
@@ -144,9 +145,12 @@ func updateDNS(c *config.DNS, t *config.Tun) {
 	}
 
 	resolver.DefaultResolver = r
-	resolver.MainResolver = mr
 	resolver.DefaultHostMapper = m
 
+	if pr.HasProxyServer() {
+		resolver.ProxyServerHostResolver = pr
+	}
+
 	if t.Enable {
 		resolver.DefaultLocalServer = dns.NewLocalServer(r, m)
 	}
@@ -156,9 +160,9 @@ func updateDNS(c *config.DNS, t *config.Tun) {
 	} else {
 		if !t.Enable {
 			resolver.DefaultResolver = nil
-			resolver.MainResolver = nil
 			resolver.DefaultHostMapper = nil
 			resolver.DefaultLocalServer = nil
+			resolver.ProxyServerHostResolver = nil
 		}
 		dns.ReCreateServer("", nil, nil)
 	}