refactor: Enhance MySQL inbound handling with identity provider support

option/mysql.go

@@ -3,11 +3,15 @@ package option
 type MySQLInboundOptions struct {
 	ListenOptions
 	InboundTLSOptionsContainer
-	Username  string                   `json:"username,omitempty"`
+	Users     []MySQLUser              `json:"users,omitempty"`
-	Password  string                   `json:"password,omitempty"`
 	Multiplex *InboundMultiplexOptions `json:"multiplex,omitempty"`
 }
 
+type MySQLUser struct {
+	User     string `json:"user,omitempty"`
+	Password string `json:"password,omitempty"`
+}
+
 type MySQLOutboundOptions struct {
 	DialerOptions
 	ServerOptions

protocol/mysql/inbound.go

@@ -33,22 +33,23 @@ var _ adapter.TCPInjectableInbound = (*Inbound)(nil)
 
 type Inbound struct {
 	inbound.Adapter
-	router      adapter.ConnectionRouterEx
+	router           adapter.ConnectionRouterEx
-	logger      logger.ContextLogger
+	logger           logger.ContextLogger
-	listener    *listener.Listener
+	listener         *listener.Listener
-	tlsConfig   boxTLS.ServerConfig
+	tlsConfig        boxTLS.ServerConfig
-	username    string
+	identityProvider *server.InMemoryProvider
-	password    string
+	mysqlServer      *server.Server
-	mysqlServer *server.Server
 }
 
 func NewInbound(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.MySQLInboundOptions) (adapter.Inbound, error) {
 	inbound := &Inbound{
-		Adapter:  inbound.NewAdapter(C.TypeMySQL, tag),
+		Adapter:          inbound.NewAdapter(C.TypeMySQL, tag),
-		router:   router,
+		router:           router,
-		logger:   logger,
+		logger:           logger,
-		username: options.Username,
+		identityProvider: server.NewInMemoryProvider(),
-		password: options.Password,
+	}
+	for _, user := range options.Users {
+		inbound.identityProvider.AddUser(user.User, user.Password)
 	}
 
 	if options.TLS == nil || !options.TLS.Enabled {
@@ -112,12 +113,8 @@ func (h *Inbound) Close() error {
 }
 
 func (h *Inbound) NewConnectionEx(ctx context.Context, conn net.Conn, metadata adapter.InboundContext, onClose N.CloseHandlerFunc) {
-	// Create credential provider for this connection
-	provider := server.NewInMemoryProvider()
-	provider.AddUser(h.username, h.password)
-
 	// Use go-mysql server to perform the MySQL handshake (which negotiates TLS)
-	mysqlConn, err := h.mysqlServer.NewCustomizedConn(conn, provider, &emptyHandler{})
+	mysqlConn, err := h.mysqlServer.NewCustomizedConn(conn, h.identityProvider, &emptyHandler{})
 	if err != nil {
 		N.CloseOnHandshakeFailure(conn, onClose, err)
 		h.logger.ErrorContext(ctx, E.Cause(err, "process connection from ", metadata.Source, ": MySQL handshake"))
@@ -131,13 +128,13 @@ func (h *Inbound) NewConnectionEx(ctx context.Context, conn net.Conn, metadata a
 	h.logger.InfoContext(ctx, "MySQL handshake completed from ", metadata.Source)
 
 	// Handle smux session over the TLS-encrypted connection
-	err = h.handleMuxSession(ctx, tlsConn, metadata.Source, onClose)
+	err = h.handleMuxSession(ctx, tlsConn, metadata.Source, onClose, mysqlConn.GetUser())
 	if err != nil && !E.IsClosed(err) {
 		h.logger.ErrorContext(ctx, E.Cause(err, "process mux session from ", metadata.Source))
 	}
 }
 
-func (h *Inbound) handleMuxSession(ctx context.Context, conn net.Conn, source M.Socksaddr, onClose N.CloseHandlerFunc) error {
+func (h *Inbound) handleMuxSession(ctx context.Context, conn net.Conn, source M.Socksaddr, onClose N.CloseHandlerFunc, user string) error {
 	session, err := smux.Server(conn, smuxConfig())
 	if err != nil {
 		if onClose != nil {
@@ -152,7 +149,7 @@ func (h *Inbound) handleMuxSession(ctx context.Context, conn net.Conn, source M.
 			if sErr != nil {
 				return sErr
 			}
-			go h.handleMuxStream(ctx, stream, source)
+			go h.handleMuxStream(ctx, stream, source, user)
 		}
 	})
 	group.Cleanup(func() {
@@ -164,14 +161,14 @@ func (h *Inbound) handleMuxSession(ctx context.Context, conn net.Conn, source M.
 	return group.Run(ctx)
 }
 
-func (h *Inbound) handleMuxStream(ctx context.Context, conn net.Conn, source M.Socksaddr) {
+func (h *Inbound) handleMuxStream(ctx context.Context, conn net.Conn, source M.Socksaddr, user string) {
-	err := h.handleMuxStream0(ctx, conn, source)
+	err := h.handleMuxStream0(ctx, conn, source, user)
 	if err != nil {
 		h.logger.ErrorContext(ctx, E.Cause(err, "process mux stream"))
 	}
 }
 
-func (h *Inbound) handleMuxStream0(ctx context.Context, conn net.Conn, source M.Socksaddr) error {
+func (h *Inbound) handleMuxStream0(ctx context.Context, conn net.Conn, source M.Socksaddr, user string) error {
 	// Read destination from the stream header:
 	// 1 byte command (0x01=TCP, 0x03=UDP)
 	// then socks address (using SocksaddrSerializer)
@@ -191,6 +188,7 @@ func (h *Inbound) handleMuxStream0(ctx context.Context, conn net.Conn, source M.
 	metadata.Inbound = h.Tag()
 	metadata.InboundType = h.Type()
 	metadata.Source = source
+	metadata.User = user
 
 	switch command {
 	case commandTCP: