Feat: DNS hosts support multiple addresses

app/dns/config.pb.go

@@ -510,8 +510,7 @@ type Config_HostMapping struct {
 	Domain string             `protobuf:"bytes,2,opt,name=domain,proto3" json:"domain,omitempty"`
 	Ip     [][]byte           `protobuf:"bytes,3,rep,name=ip,proto3" json:"ip,omitempty"`
 	// ProxiedDomain indicates the mapped domain has the same IP address on this
-	// domain. Xray will use this domain for IP queries. This field is only
-	// effective if ip is empty.
+	// domain. Xray will use this domain for IP queries.
 	ProxiedDomain string `protobuf:"bytes,4,opt,name=proxied_domain,json=proxiedDomain,proto3" json:"proxied_domain,omitempty"`
 }
 

app/dns/config.proto

@@ -73,8 +73,7 @@ message Config {
     repeated bytes ip = 3;
 
     // ProxiedDomain indicates the mapped domain has the same IP address on this
-    // domain. Xray will use this domain for IP queries. This field is only
-    // effective if ip is empty.
+    // domain. Xray will use this domain for IP queries.
     string proxied_domain = 4;
   }
 

app/dns/dns.go

@@ -222,7 +222,7 @@ func (s *DNS) lookupIPInternal(domain string, option *dns.IPOption) ([]net.IP, e
 		// Successfully found ip records in static host.
 		// Skip hosts mapping result in FakeDNS query.
 		if isIPQuery(option) {
-			newError("returning ", len(addrs), " IPs for domain ", domain).WriteToLog()
+			newError("returning ", len(addrs), " IP(s) for domain ", domain, " -> ", addrs).WriteToLog()
 			return toNetIP(addrs)
 		}
 	}

app/dns/hosts.go

@@ -47,6 +47,9 @@ func NewStaticHosts(hosts []*Config_HostMapping, legacy map[string]*net.IPOrDoma
 		id := g.Add(matcher)
 		ips := make([]net.Address, 0, len(mapping.Ip)+1)
 		switch {
+		case len(mapping.ProxiedDomain) > 0:
+			ips = append(ips, net.DomainAddress(mapping.ProxiedDomain))
+
 		case len(mapping.Ip) > 0:
 			for _, ip := range mapping.Ip {
 				addr := net.IPAddress(ip)
@@ -56,18 +59,10 @@ func NewStaticHosts(hosts []*Config_HostMapping, legacy map[string]*net.IPOrDoma
 				ips = append(ips, addr)
 			}
 
-		case len(mapping.ProxiedDomain) > 0:
-			ips = append(ips, net.DomainAddress(mapping.ProxiedDomain))
-
 		default:
 			return nil, newError("neither IP address nor proxied domain specified for domain: ", mapping.Domain).AtWarning()
 		}
 
-		// Special handling for localhost IPv6. This is a dirty workaround as JSON config supports only single IP mapping.
-		if len(ips) == 1 && ips[0] == net.LocalHostIP {
-			ips = append(ips, net.LocalHostIPv6)
-		}
-
 		sh.ips[id] = ips
 	}
 
@@ -100,6 +95,7 @@ func (h *StaticHosts) lookup(domain string, option *dns.IPOption, maxDepth int)
 	case len(addrs) == 0: // Not recorded in static hosts, return nil
 		return nil
 	case len(addrs) == 1 && addrs[0].Family().IsDomain(): // Try to unwrap domain
+		newError("found replaced domain: ", domain, " -> ", addrs[0].Domain(), ". Try to unwrap it").AtDebug().WriteToLog()
 		if maxDepth > 0 {
 			unwrapped := h.lookup(addrs[0].Domain(), option, maxDepth-1)
 			if unwrapped != nil {

app/dns/hosts_test.go

@@ -20,6 +20,20 @@ func TestStaticHosts(t *testing.T) {
 				{1, 1, 1, 1},
 			},
 		},
+		{
+			Type:   DomainMatchingType_Full,
+			Domain: "proxy.example.com",
+			Ip: [][]byte{
+				{1, 2, 3, 4},
+				{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
+			},
+			ProxiedDomain: "another-proxy.example.com",
+		},
+		{
+			Type:          DomainMatchingType_Full,
+			Domain:        "proxy2.example.com",
+			ProxiedDomain: "proxy.example.com",
+		},
 		{
 			Type:   DomainMatchingType_Subdomain,
 			Domain: "example.cn",
@@ -32,6 +46,7 @@ func TestStaticHosts(t *testing.T) {
 			Domain: "baidu.com",
 			Ip: [][]byte{
 				{127, 0, 0, 1},
+				{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
 			},
 		},
 	}
@@ -52,6 +67,32 @@ func TestStaticHosts(t *testing.T) {
 		}
 	}
 
+	{
+		domain := hosts.Lookup("proxy.example.com", &dns.IPOption{
+			IPv4Enable: true,
+			IPv6Enable: false,
+		})
+		if len(domain) != 1 {
+			t.Error("expect 1 domain, but got ", len(domain))
+		}
+		if diff := cmp.Diff(domain[0].Domain(), "another-proxy.example.com"); diff != "" {
+			t.Error(diff)
+		}
+	}
+
+	{
+		domain := hosts.Lookup("proxy2.example.com", &dns.IPOption{
+			IPv4Enable: true,
+			IPv6Enable: false,
+		})
+		if len(domain) != 1 {
+			t.Error("expect 1 domain, but got ", len(domain))
+		}
+		if diff := cmp.Diff(domain[0].Domain(), "another-proxy.example.com"); diff != "" {
+			t.Error(diff)
+		}
+	}
+
 	{
 		ips := hosts.Lookup("www.example.cn", &dns.IPOption{
 			IPv4Enable: true,