proxy dns with NOTIMP error (#2954)

* proxy dns with NOTIMP error

* fix compile error when protoc is relative link

```
$ go generate
...
proto.go
fork/exec ../Cellar/protobuf/28.3/bin/protoc: no such file or directory
exit status 1
proto.go:5: running "go": exit status 1
context_test.go
functions_test.go
v2ray_test.go
$ ls -l `which protoc`
lrwxr-xr-x 1 local admin 34 Nov  1 13:56 /opt/homebrew/bin/protoc -> ../Cellar/protobuf/28.3/bin/protoc
```

* add nonIPQuery for dns config

* go generate with only dns.proto

* Try Allowing Github actions

* fix merge error

* apply coding style

---------

Co-authored-by: local <local@localhost>
Co-authored-by: Shelikhoo <xiaokangwang@outlook.com>

infra/vprotogen/main.go

@@ -182,10 +182,6 @@ func main() {
 		os.Exit(1)
 	}
 
-	if linkPath, err := os.Readlink(protoc); err == nil {
-		protoc = linkPath
-	}
-
 	installedVersion, err := getInstalledProtocVersion(protoc)
 	if err != nil {
 		fmt.Println(err)

proxy/dns/config.pb.go

@@ -25,6 +25,7 @@ type Config struct {
 	UserLevel           uint32        `protobuf:"varint,2,opt,name=user_level,json=userLevel,proto3" json:"user_level,omitempty"`
 	OverrideResponseTtl bool          `protobuf:"varint,4,opt,name=override_response_ttl,json=overrideResponseTtl,proto3" json:"override_response_ttl,omitempty"`
 	ResponseTtl         uint32        `protobuf:"varint,3,opt,name=response_ttl,json=responseTtl,proto3" json:"response_ttl,omitempty"`
+	Non_IPQuery         string        `protobuf:"bytes,5,opt,name=non_IP_query,json=nonIPQuery,proto3" json:"non_IP_query,omitempty"`
 	unknownFields       protoimpl.UnknownFields
 	sizeCache           protoimpl.SizeCache
 }
@@ -87,6 +88,13 @@ func (x *Config) GetResponseTtl() uint32 {
 	return 0
 }
 
+func (x *Config) GetNon_IPQuery() string {
+	if x != nil {
+		return x.Non_IPQuery
+	}
+	return ""
+}
+
 type SimplifiedConfig struct {
 	state               protoimpl.MessageState `protogen:"open.v1"`
 	OverrideResponseTtl bool                   `protobuf:"varint,4,opt,name=override_response_ttl,json=overrideResponseTtl,proto3" json:"override_response_ttl,omitempty"`
@@ -141,41 +149,22 @@ func (x *SimplifiedConfig) GetResponseTtl() uint32 {
 
 var File_proxy_dns_config_proto protoreflect.FileDescriptor
 
-var file_proxy_dns_config_proto_rawDesc = string([]byte{
+const file_proxy_dns_config_proto_rawDesc = "" +
-	0x0a, 0x16, 0x70, 0x72, 0x6f, 0x78, 0x79, 0x2f, 0x64, 0x6e, 0x73, 0x2f, 0x63, 0x6f, 0x6e, 0x66,
+	"\n" +
-	0x69, 0x67, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x12, 0x14, 0x76, 0x32, 0x72, 0x61, 0x79, 0x2e,
+	"\x16proxy/dns/config.proto\x12\x14v2ray.core.proxy.dns\x1a\x1ccommon/net/destination.proto\x1a common/protoext/extensions.proto\"\xd9\x01\n" +
-	0x63, 0x6f, 0x72, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x78, 0x79, 0x2e, 0x64, 0x6e, 0x73, 0x1a, 0x1c,
+	"\x06Config\x127\n" +
-	0x63, 0x6f, 0x6d, 0x6d, 0x6f, 0x6e, 0x2f, 0x6e, 0x65, 0x74, 0x2f, 0x64, 0x65, 0x73, 0x74, 0x69,
+	"\x06server\x18\x01 \x01(\v2\x1f.v2ray.core.common.net.EndpointR\x06server\x12\x1d\n" +
-	0x6e, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x1a, 0x20, 0x63, 0x6f,
+	"\n" +
-	0x6d, 0x6d, 0x6f, 0x6e, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x65, 0x78, 0x74, 0x2f, 0x65, 0x78,
+	"user_level\x18\x02 \x01(\rR\tuserLevel\x122\n" +
-	0x74, 0x65, 0x6e, 0x73, 0x69, 0x6f, 0x6e, 0x73, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x22, 0xb7,
+	"\x15override_response_ttl\x18\x04 \x01(\bR\x13overrideResponseTtl\x12!\n" +
-	0x01, 0x0a, 0x06, 0x43, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x12, 0x37, 0x0a, 0x06, 0x73, 0x65, 0x72,
+	"\fresponse_ttl\x18\x03 \x01(\rR\vresponseTtl\x12 \n" +
-	0x76, 0x65, 0x72, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x1f, 0x2e, 0x76, 0x32, 0x72, 0x61,
+	"\fnon_IP_query\x18\x05 \x01(\tR\n" +
-	0x79, 0x2e, 0x63, 0x6f, 0x72, 0x65, 0x2e, 0x63, 0x6f, 0x6d, 0x6d, 0x6f, 0x6e, 0x2e, 0x6e, 0x65,
+	"nonIPQuery\"~\n" +
-	0x74, 0x2e, 0x45, 0x6e, 0x64, 0x70, 0x6f, 0x69, 0x6e, 0x74, 0x52, 0x06, 0x73, 0x65, 0x72, 0x76,
+	"\x10SimplifiedConfig\x122\n" +
-	0x65, 0x72, 0x12, 0x1d, 0x0a, 0x0a, 0x75, 0x73, 0x65, 0x72, 0x5f, 0x6c, 0x65, 0x76, 0x65, 0x6c,
+	"\x15override_response_ttl\x18\x04 \x01(\bR\x13overrideResponseTtl\x12!\n" +
-	0x18, 0x02, 0x20, 0x01, 0x28, 0x0d, 0x52, 0x09, 0x75, 0x73, 0x65, 0x72, 0x4c, 0x65, 0x76, 0x65,
+	"\fresponse_ttl\x18\x03 \x01(\rR\vresponseTtl:\x13\x82\xb5\x18\x0f\n" +
-	0x6c, 0x12, 0x32, 0x0a, 0x15, 0x6f, 0x76, 0x65, 0x72, 0x72, 0x69, 0x64, 0x65, 0x5f, 0x72, 0x65,
+	"\boutbound\x12\x03dnsB]\n" +
-	0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x5f, 0x74, 0x74, 0x6c, 0x18, 0x04, 0x20, 0x01, 0x28, 0x08,
+	"\x18com.v2ray.core.proxy.dnsP\x01Z(github.com/v2fly/v2ray-core/v5/proxy/dns\xaa\x02\x14V2Ray.Core.Proxy.Dnsb\x06proto3"
-	0x52, 0x13, 0x6f, 0x76, 0x65, 0x72, 0x72, 0x69, 0x64, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e,
-	0x73, 0x65, 0x54, 0x74, 0x6c, 0x12, 0x21, 0x0a, 0x0c, 0x72, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73,
-	0x65, 0x5f, 0x74, 0x74, 0x6c, 0x18, 0x03, 0x20, 0x01, 0x28, 0x0d, 0x52, 0x0b, 0x72, 0x65, 0x73,
-	0x70, 0x6f, 0x6e, 0x73, 0x65, 0x54, 0x74, 0x6c, 0x22, 0x7e, 0x0a, 0x10, 0x53, 0x69, 0x6d, 0x70,
-	0x6c, 0x69, 0x66, 0x69, 0x65, 0x64, 0x43, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x12, 0x32, 0x0a, 0x15,
-	0x6f, 0x76, 0x65, 0x72, 0x72, 0x69, 0x64, 0x65, 0x5f, 0x72, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73,
-	0x65, 0x5f, 0x74, 0x74, 0x6c, 0x18, 0x04, 0x20, 0x01, 0x28, 0x08, 0x52, 0x13, 0x6f, 0x76, 0x65,
-	0x72, 0x72, 0x69, 0x64, 0x65, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x54, 0x74, 0x6c,
-	0x12, 0x21, 0x0a, 0x0c, 0x72, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x5f, 0x74, 0x74, 0x6c,
-	0x18, 0x03, 0x20, 0x01, 0x28, 0x0d, 0x52, 0x0b, 0x72, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65,
-	0x54, 0x74, 0x6c, 0x3a, 0x13, 0x82, 0xb5, 0x18, 0x0f, 0x0a, 0x08, 0x6f, 0x75, 0x74, 0x62, 0x6f,
-	0x75, 0x6e, 0x64, 0x12, 0x03, 0x64, 0x6e, 0x73, 0x42, 0x5d, 0x0a, 0x18, 0x63, 0x6f, 0x6d, 0x2e,
-	0x76, 0x32, 0x72, 0x61, 0x79, 0x2e, 0x63, 0x6f, 0x72, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x78, 0x79,
-	0x2e, 0x64, 0x6e, 0x73, 0x50, 0x01, 0x5a, 0x28, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63,
-	0x6f, 0x6d, 0x2f, 0x76, 0x32, 0x66, 0x6c, 0x79, 0x2f, 0x76, 0x32, 0x72, 0x61, 0x79, 0x2d, 0x63,
-	0x6f, 0x72, 0x65, 0x2f, 0x76, 0x35, 0x2f, 0x70, 0x72, 0x6f, 0x78, 0x79, 0x2f, 0x64, 0x6e, 0x73,
-	0xaa, 0x02, 0x14, 0x56, 0x32, 0x52, 0x61, 0x79, 0x2e, 0x43, 0x6f, 0x72, 0x65, 0x2e, 0x50, 0x72,
-	0x6f, 0x78, 0x79, 0x2e, 0x44, 0x6e, 0x73, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
-})
 
 var (
 	file_proxy_dns_config_proto_rawDescOnce sync.Once

proxy/dns/config.proto

@@ -14,9 +14,9 @@ message Config {
   // original one.
   v2ray.core.common.net.Endpoint server = 1;
   uint32 user_level = 2;
-
   bool override_response_ttl = 4;
   uint32 response_ttl = 3;
+  string non_IP_query = 5;
 }
 
 message SimplifiedConfig {
@@ -25,4 +25,4 @@ message SimplifiedConfig {
 
   bool override_response_ttl = 4;
   uint32 response_ttl = 3;
-}
+}

proxy/dns/dns.go

@@ -57,6 +57,8 @@ type Handler struct {
 	timeout         time.Duration
 
 	config *Config
+
+	nonIPQuery string
 }
 
 func (h *Handler) Init(config *Config, dnsClient dns.Client, policyManager policy.Manager) error {
@@ -88,6 +90,8 @@ func (h *Handler) Init(config *Config, dnsClient dns.Client, policyManager polic
 	}
 
 	h.config = config
+
+	h.nonIPQuery = config.Non_IPQuery
 	return nil
 }
 
@@ -200,15 +204,16 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, d internet.
 
 			if !h.isOwnLink(ctx) {
 				isIPQuery, domain, id, qType := parseIPQuery(b.Bytes())
-				if isIPQuery {
+				if isIPQuery || h.nonIPQuery != "drop" {
 					if domain, err := strmatcher.ToDomain(domain); err == nil {
 						go h.handleIPQuery(id, qType, domain, writer)
-						continue
+					} else {
+						h.handleDNSError(id, dnsmessage.RCodeFormatError, writer)
 					}
+				} else {
+					h.handleDNSError(id, dnsmessage.RCodeNotImplemented, writer)
 				}
-			}
+			} else if err := connWriter.WriteMessage(b); err != nil {
-
-			if err := connWriter.WriteMessage(b); err != nil {
 				return err
 			}
 		}
@@ -305,6 +310,35 @@ func (h *Handler) handleIPQuery(id uint16, qType dnsmessage.Type, domain string,
 	}
 }
 
+func (h *Handler) handleDNSError(id uint16, rCode dnsmessage.RCode, writer dns_proto.MessageWriter) {
+	var err error
+
+	b := buf.New()
+	rawBytes := b.Extend(buf.Size)
+	builder := dnsmessage.NewBuilder(rawBytes[:0], dnsmessage.Header{
+		ID:                 id,
+		RCode:              rCode,
+		RecursionAvailable: true,
+		RecursionDesired:   true,
+		Response:           true,
+	})
+	builder.EnableCompression()
+	common.Must(builder.StartQuestions())
+	common.Must(builder.StartAnswers())
+
+	msgBytes, err := builder.Finish()
+	if err != nil {
+		newError("pack message").Base(err).WriteToLog()
+		b.Release()
+		return
+	}
+	b.Resize(0, int32(len(msgBytes)))
+
+	if err := writer.WriteMessage(b); err != nil {
+		newError("write IP answer").Base(err).WriteToLog()
+	}
+}
+
 type outboundConn struct {
 	access sync.Mutex
 	dialer func() (internet.Connection, error)