modify TSI handshake to correctly handle the case of TSI_INCOMPLETE_DATA

test/core/tsi/transport_security_test_lib.c

@@ -350,7 +350,9 @@ static void do_handshaker_next(handshaker_args *args) {
   tsi_handshaker_result *handshaker_result = NULL;
   unsigned char *bytes_to_send = NULL;
   size_t bytes_to_send_size = 0;
+  tsi_result result = TSI_OK;
   /* Receive data from peer, if available. */
+  do {
     size_t buf_size = args->handshake_buffer_size;
     receive_bytes_from_peer(args->fixture, &args->handshake_buffer, &buf_size,
                             args->is_client);
@@ -358,17 +360,18 @@ static void do_handshaker_next(handshaker_args *args) {
       args->transferred_data = true;
     }
     /* Peform handshaker next. */
-  tsi_result result = tsi_handshaker_next(
+    result = tsi_handshaker_next(handshaker, args->handshake_buffer, buf_size,
-      handshaker, args->handshake_buffer, buf_size,
+                                 (const unsigned char **)&bytes_to_send,
-      (const unsigned char **)&bytes_to_send, &bytes_to_send_size,
+                                 &bytes_to_send_size, &handshaker_result,
-      &handshaker_result, &on_handshake_next_done_wrapper, args);
+                                 &on_handshake_next_done_wrapper, args);
     if (result != TSI_ASYNC) {
-    args->error = on_handshake_next_done(result, args, bytes_to_send,
+      args->error = on_handshake_next_done(
-                                         bytes_to_send_size, handshaker_result);
+          result, args, bytes_to_send, bytes_to_send_size, handshaker_result);
       if (args->error != GRPC_ERROR_NONE) {
         return;
       }
     }
+  } while (result == TSI_INCOMPLETE_DATA);
   notification_wait(fixture);
 }
 

test/core/tsi/transport_security_test_lib.h

@@ -21,6 +21,8 @@
 
 #include "src/core/tsi/transport_security_interface.h"
 
+#include <grpc/support/sync.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif