[common] Exchange messages between servers

3 files changed, 57 insertions, 23 deletions

diff --git a/core/data.go b/core/data.go
index a96b56f..dd2777f 100644
--- a/core/data.go
+++ b/core/data.go
@@ -16,13 +16,14 @@ type Wrapper interface {
 type PayloadType uint8
 
 const (
-	PayloadUnknown   PayloadType = 0x00
-	PayloadSuccess               = 0x01
-	PayloadError                 = 0x02
-	PayloadHandshake             = 0x03
-	PayloadAuth                  = 0x04
-	PayloadMessage               = 0x05
-	PayloadTest                  = 0xFF
+	PayloadUnknown    PayloadType = 0x00
+	PayloadSuccess                = 0x01
+	PayloadError                  = 0x02
+	PayloadHandshake              = 0x03
+	PayloadUserAuth               = 0x04
+	PayloadMessage                = 0x05
+	PayloadServerAuth             = 0x06
+	PayloadTest                   = 0xFF
 )
 
 type ErrorType uint8
@@ -33,6 +34,14 @@ const (
 	ErrorNotFound             = 0x02
 )
 
+type ConnType uint8
+
+const (
+	ConnTypeUnknown ConnType = 0x00
+	ConnTypeUser             = 0x01
+	ConnTypeServer           = 0x02
+)
+
 type Frame struct {
 	Length  uint16
 	Type    PayloadType
@@ -99,7 +108,7 @@ func Decode(buf io.Reader) (any, error) {
 
 	err := binary.Read(buf, binary.BigEndian, &pTypeByte)
 	if err != nil {
-		return nil, fmt.Errorf("cannot read payload type: %v", err)
+		return nil, fmt.Errorf("cannot read payload type: %w", err)
 	}
 
 	pType := PayloadType(pTypeByte)
@@ -107,7 +116,7 @@ func Decode(buf io.Reader) (any, error) {
 	var pLen uint16
 	err = binary.Read(buf, binary.BigEndian, &pLen)
 	if err != nil {
-		return nil, fmt.Errorf("cannot read payload length: %v", err)
+		return nil, fmt.Errorf("cannot read payload length: %w", err)
 	}
 
 	switch pType {
@@ -117,8 +126,10 @@ func Decode(buf io.Reader) (any, error) {
 		return DecodeError(buf)
 	case PayloadHandshake:
 		return DecodeHandshake(buf)
-	case PayloadAuth:
-		return DecodeAuth(buf)
+	case PayloadUserAuth:
+		return DecodeUserAuth(buf)
+	case PayloadServerAuth:
+		return DecodeServerAuth(buf)
 	case PayloadMessage:
 		return DecodeMessage(buf)
 	case PayloadTest:
diff --git a/core/errors.go b/core/errors.go
index a50fbf7..ed6702d 100644
--- a/core/errors.go
+++ b/core/errors.go
@@ -3,10 +3,11 @@ package core
 import "errors"
 
 var (
-	ErrUnexpectedPayloadType = errors.New("unexpected payload type")
-	ErrAuthInvalidUser       = errors.New("invalid user")
-	ErrAuthInvalidPassword   = errors.New("invalid password")
-	ErrInvalidAddress        = errors.New("invalid address")
-	ErrNotSupported          = errors.New("not supported")
-	ErrDisconnected          = errors.New("disconnected")
+	ErrUnexpectedPayloadType   = errors.New("unexpected payload type")
+	ErrAuthInvalidUser         = errors.New("invalid user")
+	ErrAuthInvalidPassword     = errors.New("invalid password")
+	ErrAuthReverseLookupFailed = errors.New("declared name does not match with DNS name")
+	ErrInvalidAddress          = errors.New("invalid address")
+	ErrNotSupported            = errors.New("not supported")
+	ErrDisconnected            = errors.New("disconnected")
 )
diff --git a/core/payload.go b/core/payload.go
index b8e8b9f..e943647 100644
--- a/core/payload.go
+++ b/core/payload.go
@@ -36,11 +36,12 @@ func DecodeError(buf io.Reader) (Error, error) {
 
 type Handshake struct {
 	Major, Minor uint8
+	ConnType     ConnType
 }
 
 func (h Handshake) Wrap() (PayloadType, []any) {
 	return PayloadHandshake, []any{
-		h.Major, h.Minor,
+		h.Major, h.Minor, h.ConnType,
 	}
 }
 
@@ -57,22 +58,27 @@ func DecodeHandshake(buf io.Reader) (Handshake, error) {
 		return h, err
 	}
 
+	err = decodeNumeric(buf, &h.ConnType)
+	if err != nil {
+		return h, err
+	}
+
 	return h, nil
 }
 
-type Auth struct {
+type UserAuth struct {
 	Name string
 	Pass string
 }
 
-func (a Auth) Wrap() (PayloadType, []any) {
-	return PayloadAuth, []any{
+func (a UserAuth) Wrap() (PayloadType, []any) {
+	return PayloadUserAuth, []any{
 		a.Name, a.Pass,
 	}
 }
 
-func DecodeAuth(buf io.Reader) (Auth, error) {
-	var a Auth
+func DecodeUserAuth(buf io.Reader) (UserAuth, error) {
+	var a UserAuth
 	err := decodeString(buf, &a.Name)
 	if err != nil {
 		return a, err
@@ -86,6 +92,22 @@ func DecodeAuth(buf io.Reader) (Auth, error) {
 	return a, nil
 }
 
+type ServerAuth struct {
+	Name string
+}
+
+func (a ServerAuth) Wrap() (PayloadType, []any) {
+	return PayloadServerAuth, []any{
+		a.Name,
+	}
+}
+
+func DecodeServerAuth(buf io.Reader) (ServerAuth, error) {
+	var a ServerAuth
+	err := decodeString(buf, &a.Name)
+	return a, err
+}
+
 type Message struct {
 	Source    string
 	Target    string