Unify error checking by introducing error codes

common/errors/errors.go

@@ -4,55 +4,86 @@ import (
 	"fmt"
 )
 
+func HasCode(err error, code int) bool {
+	if errWithCode, ok := err.(ErrorWithCode); ok {
+		return errWithCode.Code() == code
+	}
+	return false
+}
+
+type ErrorWithCode interface {
+	error
+	Code() int
+}
+
+type ErrorCode int
+
+func (code ErrorCode) Code() int {
+	return int(code)
+}
+
+func (code ErrorCode) Prefix() string {
+	return fmt.Sprintf("[Error 0x%04X] ", code.Code())
+}
+
 type AuthenticationError struct {
+	ErrorCode
 	AuthDetail interface{}
 }
 
 func NewAuthenticationError(detail interface{}) AuthenticationError {
 	return AuthenticationError{
+		ErrorCode:  1,
 		AuthDetail: detail,
 	}
 }
 
 func (err AuthenticationError) Error() string {
-	return fmt.Sprintf("[Error 0x0001] Invalid auth %v", err.AuthDetail)
+	return fmt.Sprintf("%sInvalid auth %v", err.Prefix(), err.AuthDetail)
 }
 
 type ProtocolVersionError struct {
+	ErrorCode
 	Version int
 }
 
 func NewProtocolVersionError(version int) ProtocolVersionError {
 	return ProtocolVersionError{
-		Version: version,
+		ErrorCode: 2,
+		Version:   version,
 	}
 }
 
 func (err ProtocolVersionError) Error() string {
-	return fmt.Sprintf("[Error 0x0002] Invalid version %d", err.Version)
+	return fmt.Sprintf("%sInvalid version %d", err.Prefix(), err.Version)
 }
 
 type CorruptedPacketError struct {
+	ErrorCode
 }
 
+var corruptedPacketErrorInstance = CorruptedPacketError{ErrorCode: 3}
+
 func NewCorruptedPacketError() CorruptedPacketError {
-	return CorruptedPacketError{}
+	return corruptedPacketErrorInstance
 }
 
 func (err CorruptedPacketError) Error() string {
-	return "[Error 0x0003] Corrupted packet."
+	return err.Prefix() + "Corrupted packet."
 }
 
 type IPFormatError struct {
+	ErrorCode
 	IP []byte
 }
 
 func NewIPFormatError(ip []byte) IPFormatError {
 	return IPFormatError{
-		IP: ip,
+		ErrorCode: 4,
+		IP:        ip,
 	}
 }
 
 func (err IPFormatError) Error() string {
-	return fmt.Sprintf("[Error 0x0004] Invalid IP %v", err.IP)
+	return fmt.Sprintf("%sInvalid IP %v", err.Prefix(), err.IP)
 }

common/errors/errors_test.go

@@ -0,0 +1,23 @@
+package errors_test
+
+import (
+	"testing"
+
+	"github.com/v2ray/v2ray-core/common/errors"
+	"github.com/v2ray/v2ray-core/testing/unit"
+)
+
+type MockError struct {
+	errors.ErrorCode
+}
+
+func (err MockError) Error() string {
+	return "This is a fake error."
+}
+
+func TestHasCode(t *testing.T) {
+	assert := unit.Assert(t)
+
+	err := MockError{ErrorCode: 101}
+	assert.Error(err).HasCode(101)
+}

proxy/socks/protocol/socks.go

@@ -2,10 +2,9 @@ package protocol
 
 import (
 	"encoding/binary"
-	"errors"
-	"fmt"
 	"io"
 
+	"github.com/v2ray/v2ray-core/common/errors"
 	"github.com/v2ray/v2ray-core/common/log"
 	v2net "github.com/v2ray/v2ray-core/common/net"
 )
@@ -23,10 +22,6 @@ const (
 	Socks4RequestRejected = byte(91)
 )
 
-var (
-	ErrorSocksVersion4 = errors.New("Using SOCKS version 4.")
-)
-
 // Authentication request header of Socks5 protocol
 type Socks5AuthenticationRequest struct {
 	version     byte
@@ -34,13 +29,6 @@ type Socks5AuthenticationRequest struct {
 	authMethods [256]byte
 }
 
-type Socks4AuthenticationRequest struct {
-	Version byte
-	Command byte
-	Port    uint16
-	IP      [4]byte
-}
-
 func (request *Socks5AuthenticationRequest) HasAuthMethod(method byte) bool {
 	for i := 0; i < int(request.nMethods); i++ {
 		if request.authMethods[i] == method {
@@ -54,11 +42,11 @@ func ReadAuthentication(reader io.Reader) (auth Socks5AuthenticationRequest, aut
 	buffer := make([]byte, 256)
 	nBytes, err := reader.Read(buffer)
 	if err != nil {
-		log.Error("Failed to read socks authentication: %v", err)
 		return
 	}
 	if nBytes < 2 {
-		err = fmt.Errorf("Expected 2 bytes read, but actaully %d bytes read", nBytes)
+		log.Info("Socks expected 2 bytes read, but only %d bytes read", nBytes)
+		err = errors.NewCorruptedPacketError()
 		return
 	}
 
@@ -67,24 +55,26 @@ func ReadAuthentication(reader io.Reader) (auth Socks5AuthenticationRequest, aut
 		auth4.Command = buffer[1]
 		auth4.Port = binary.BigEndian.Uint16(buffer[2:4])
 		copy(auth4.IP[:], buffer[4:8])
-		err = ErrorSocksVersion4
+		err = NewSocksVersion4Error()
 		return
 	}
 
 	auth.version = buffer[0]
 	if auth.version != socksVersion {
-		err = fmt.Errorf("Unknown SOCKS version %d", auth.version)
+		err = errors.NewProtocolVersionError(int(auth.version))
 		return
 	}
 
 	auth.nMethods = buffer[1]
 	if auth.nMethods <= 0 {
-		err = fmt.Errorf("Zero length of authentication methods")
+		log.Info("Zero length of authentication methods")
+		err = errors.NewCorruptedPacketError()
 		return
 	}
 
 	if nBytes-2 != int(auth.nMethods) {
-		err = fmt.Errorf("Unmatching number of auth methods, expecting %d, but got %d", auth.nMethods, nBytes)
+		log.Info("Unmatching number of auth methods, expecting %d, but got %d", auth.nMethods, nBytes)
+		err = errors.NewCorruptedPacketError()
 		return
 	}
 	copy(auth.authMethods[:], buffer[2:nBytes])
@@ -207,14 +197,13 @@ type Socks5Request struct {
 }
 
 func ReadRequest(reader io.Reader) (request *Socks5Request, err error) {
-
-	buffer := make([]byte, 4)
-	nBytes, err := reader.Read(buffer)
+	buffer := make([]byte, 256)
+	nBytes, err := reader.Read(buffer[:4])
 	if err != nil {
 		return
 	}
-	if nBytes < len(buffer) {
-		err = fmt.Errorf("Unable to read request.")
+	if nBytes < 4 {
+		err = errors.NewCorruptedPacketError()
 		return
 	}
 	request = &Socks5Request{
@@ -230,11 +219,10 @@ func ReadRequest(reader io.Reader) (request *Socks5Request, err error) {
 			return
 		}
 		if nBytes != 4 {
-			err = fmt.Errorf("Unable to read IPv4 address.")
+			err = errors.NewCorruptedPacketError()
 			return
 		}
 	case AddrTypeDomain:
-		buffer = make([]byte, 256)
 		nBytes, err = reader.Read(buffer[0:1])
 		if err != nil {
 			return
@@ -246,7 +234,8 @@ func ReadRequest(reader io.Reader) (request *Socks5Request, err error) {
 		}
 
 		if nBytes != int(domainLength) {
-			err = fmt.Errorf("Unable to read domain with %d bytes, expecting %d bytes", nBytes, domainLength)
+			log.Info("Unable to read domain with %d bytes, expecting %d bytes", nBytes, domainLength)
+			err = errors.NewCorruptedPacketError()
 			return
 		}
 		request.Domain = string(buffer[:domainLength])
@@ -256,21 +245,21 @@ func ReadRequest(reader io.Reader) (request *Socks5Request, err error) {
 			return
 		}
 		if nBytes != 16 {
-			err = fmt.Errorf("Unable to read IPv4 address.")
+			err = errors.NewCorruptedPacketError()
 			return
 		}
 	default:
-		err = fmt.Errorf("Unexpected address type %d", request.AddrType)
+		log.Info("Unexpected address type %d", request.AddrType)
+		err = errors.NewCorruptedPacketError()
 		return
 	}
 
-	buffer = make([]byte, 2)
-	nBytes, err = reader.Read(buffer)
+	nBytes, err = reader.Read(buffer[:2])
 	if err != nil {
 		return
 	}
 	if nBytes != 2 {
-		err = fmt.Errorf("Unable to read port.")
+		err = errors.NewCorruptedPacketError()
 		return
 	}
 
@@ -351,9 +340,7 @@ func (r *Socks5Response) toBytes() []byte {
 	case 0x04:
 		buffer = append(buffer, r.IPv6[:]...)
 	}
-	portBuffer := make([]byte, 2)
-	binary.BigEndian.PutUint16(portBuffer, r.Port)
-	buffer = append(buffer, portBuffer...)
+	buffer = append(buffer, byte(r.Port>>8), byte(r.Port))
 	return buffer
 }
 

proxy/socks/protocol/socks4.go

@@ -0,0 +1,29 @@
+package protocol
+
+import (
+	_ "fmt"
+
+	"github.com/v2ray/v2ray-core/common/errors"
+	_ "github.com/v2ray/v2ray-core/common/log"
+)
+
+type SocksVersion4Error struct {
+	errors.ErrorCode
+}
+
+var socksVersion4ErrorInstance = SocksVersion4Error{ErrorCode: 1000}
+
+func NewSocksVersion4Error() SocksVersion4Error {
+	return socksVersion4ErrorInstance
+}
+
+func (err SocksVersion4Error) Error() string {
+	return err.Prefix() + "Request is socks version 4."
+}
+
+type Socks4AuthenticationRequest struct {
+	Version byte
+	Command byte
+	Port    uint16
+	IP      [4]byte
+}

proxy/socks/protocol/socks_test.go

@@ -47,7 +47,7 @@ func TestAuthentication4RequestRead(t *testing.T) {
 		0x72, 0x72, 0x72, 0x72,
 	}
 	_, request4, err := ReadAuthentication(bytes.NewReader(rawRequest))
-	assert.Error(err).Equals(ErrorSocksVersion4)
+	assert.Error(err).HasCode(1000)
 	assert.Byte(request4.Version).Named("Version").Equals(0x04)
 	assert.Byte(request4.Command).Named("Command").Equals(0x01)
 	assert.Uint16(request4.Port).Named("Port").Equals(53)

proxy/socks/socks.go

@@ -2,22 +2,23 @@ package socks
 
 import (
 	_ "bufio"
-	"errors"
+	e2 "errors"
 	"io"
 	"net"
 	"strconv"
 	"sync"
 
 	"github.com/v2ray/v2ray-core"
+	"github.com/v2ray/v2ray-core/common/errors"
 	"github.com/v2ray/v2ray-core/common/log"
 	v2net "github.com/v2ray/v2ray-core/common/net"
-	protocol "github.com/v2ray/v2ray-core/proxy/socks/protocol"
+	"github.com/v2ray/v2ray-core/proxy/socks/protocol"
 )
 
 var (
-	ErrorAuthenticationFailed = errors.New("None of the authentication methods is allowed.")
-	ErrorCommandNotSupported  = errors.New("Client requested an unsupported command.")
-	ErrorInvalidUser          = errors.New("Invalid username or password.")
+	ErrorAuthenticationFailed = e2.New("None of the authentication methods is allowed.")
+	ErrorCommandNotSupported  = e2.New("Client requested an unsupported command.")
+	ErrorInvalidUser          = e2.New("Invalid username or password.")
 )
 
 // SocksServer is a SOCKS 5 proxy server
@@ -66,7 +67,7 @@ func (server *SocksServer) HandleConnection(connection net.Conn) error {
 	reader := v2net.NewTimeOutReader(4, connection)
 
 	auth, auth4, err := protocol.ReadAuthentication(reader)
-	if err != nil && err != protocol.ErrorSocksVersion4 {
+	if err != nil && !errors.HasCode(err, 1000) {
 		log.Error("Error on reading authentication: %v", err)
 		return err
 	}
@@ -74,7 +75,7 @@ func (server *SocksServer) HandleConnection(connection net.Conn) error {
 	var dest v2net.Destination
 
 	// TODO refactor this part
-	if err == protocol.ErrorSocksVersion4 {
+	if errors.HasCode(err, 1000) {
 		result := protocol.Socks4RequestGranted
 		if auth4.Command == protocol.CmdBind {
 			result = protocol.Socks4RequestRejected

testing/unit/errorsubject.go

@@ -2,7 +2,8 @@ package unit
 
 import (
 	"fmt"
-	"strings"
+
+	"github.com/v2ray/v2ray-core/common/errors"
 )
 
 type ErrorSubject struct {
@@ -43,8 +44,7 @@ func (subject *ErrorSubject) IsNil() {
 }
 
 func (subject *ErrorSubject) HasCode(code int) {
-	errorPrefix := fmt.Sprintf("[Error 0x%04X]", code)
-	if !strings.Contains(subject.value.Error(), errorPrefix) {
+	if !errors.HasCode(subject.value, code) {
 		subject.FailWithMessage(fmt.Sprintf("Not ture that %s has error code 0x%04X.", subject.DisplayString(), code))
 	}
 }