add http2 server test for unary calls that uses small frames and padding

14 files changed, 307 insertions, 77 deletions

diff --git a/doc/negative-http2-interop-test-descriptions.md b/doc/http2-interop-test-descriptions.md
index b64fe6a024..435a8de709 100644
--- a/doc/negative-http2-interop-test-descriptions.md
+++ b/doc/http2-interop-test-descriptions.md
@@ -193,3 +193,79 @@ Server Procedure:
   1. Sets MAX_CONCURRENT_STREAMS to one after the connection is made.
 
 *The assertion that the MAX_CONCURRENT_STREAMS limit is upheld occurs in the http2 library we used.*
+
+### data_frame_padding
+
+This test verifies that the client can correctly receive padded http2 data
+frames. It also stresses the client's flow control (there is a high chance
+that the sender will deadlock if the client's flow control logic doesn't
+correctly account for padding).
+
+Client Procedure:
+(Note this is the same procedure as in the "large_unary" gRPC interop tests.
+Clients should use their "large_unary" gRPC interop test implementations.)
+Procedure:
+ 1. Client calls UnaryCall with:
+
+    ```
+    {
+      response_size: 314159
+      payload:{
+        body: 271828 bytes of zeros
+      }
+    }
+    ```
+
+Client asserts:
+* call was successful
+* response payload body is 314159 bytes in size
+* clients are free to assert that the response payload body contents are zero
+  and comparing the entire response message against a golden response
+
+Server Procedure:
+  1. Reply to the client's request with a `SimpleResponse`, with a payload
+  body length of `SimpleRequest.response_size`. But send it across specific
+  http2 data frames as follows:
+    * Each http2 data frame contains a 5 byte payload and 255 bytes of padding.
+
+  * Note the 5 byte payload and 255 byte padding are partly arbitrary,
+  and other numbers are also ok. With 255 bytes of padding for each 5 bytes of
+  payload containing actual gRPC message, the 300KB response size will
+  multiply into around 15 megabytes of flow control debt, which should stress
+  flow control accounting.
+
+### no_df_padding_sanity_test
+
+This test verifies that the client can correctly receive a series of small
+data frames. Note that this test is intentionally a slight variation of
+"data_frame_padding", with the only difference being that this test doesn't use data
+frame padding when the response is sent. This test is primarily meant to
+prove correctness of the http2 server implementation and highlight failures
+of the "data_frame_padding" test.
+
+Client Procedure:
+(Note this is the same procedure as in the "large_unary" gRPC interop tests.
+Clients should use their "large_unary" gRPC interop test implementations.)
+Procedure:
+ 1. Client calls UnaryCall with:
+
+    ```
+    {
+      response_size: 314159
+      payload:{
+        body: 271828 bytes of zeros
+      }
+    }
+    ```
+
+Client asserts:
+* call was successful
+* response payload body is 314159 bytes in size
+* clients are free to assert that the response payload body contents are zero
+  and comparing the entire response message against a golden response
+
+Server Procedure:
+  1. Reply to the client's request with a `SimpleResponse`, with a payload
+  body length of `SimpleRequest.response_size`. But send it across series of
+  http2 data frames that contain 5 bytes of "payload" and zero bytes of
+  "padding" (the padding flags on the data frames should not be set).
diff --git a/test/http2_test/http2_base_server.py b/test/http2_test/http2_base_server.py
index 8de028ceb1..e158e9b703 100644
--- a/test/http2_test/http2_base_server.py
+++ b/test/http2_test/http2_base_server.py
@@ -39,6 +39,7 @@ import twisted.internet.protocol
 
 _READ_CHUNK_SIZE = 16384
 _GRPC_HEADER_SIZE = 5
+_MIN_SETTINGS_MAX_FRAME_SIZE = 16384
 
 class H2ProtocolBaseServer(twisted.internet.protocol.Protocol):
   def __init__(self):
@@ -121,38 +122,46 @@ class H2ProtocolBaseServer(twisted.internet.protocol.Protocol):
     )
     self.transport.write(self._conn.data_to_send())
 
-  def on_window_update_default(self, event):
-    # send pending data, if any
-    self.default_send(event.stream_id)
+  def on_window_update_default(self, _, pad_length=None, read_chunk_size=_READ_CHUNK_SIZE):
+    # try to resume sending on all active streams (update might be for connection)
+    for stream_id in self._send_remaining:
+      self.default_send(stream_id, pad_length=pad_length, read_chunk_size=read_chunk_size)
 
   def send_reset_stream(self):
     self._conn.reset_stream(self._stream_id)
     self.transport.write(self._conn.data_to_send())
 
-  def setup_send(self, data_to_send, stream_id):
+  def setup_send(self, data_to_send, stream_id, pad_length=None, read_chunk_size=_READ_CHUNK_SIZE):
     logging.info('Setting up data to send for stream_id: %d' % stream_id)
     self._send_remaining[stream_id] = len(data_to_send)
     self._send_offset = 0
     self._data_to_send = data_to_send
-    self.default_send(stream_id)
+    self.default_send(stream_id, pad_length=pad_length, read_chunk_size=read_chunk_size)
 
-  def default_send(self, stream_id):
+  def default_send(self, stream_id, pad_length=None, read_chunk_size=_READ_CHUNK_SIZE):
     if not self._send_remaining.has_key(stream_id):
       # not setup to send data yet
       return
 
     while self._send_remaining[stream_id] > 0:
       lfcw = self._conn.local_flow_control_window(stream_id)
-      if lfcw == 0:
+      padding_bytes = pad_length + 1 if pad_length is not None else 0
+      if lfcw - padding_bytes <= 0:
+        logging.info('Stream %d. lfcw: %d. padding bytes: %d. not enough quota yet' % (stream_id, lfcw, padding_bytes))
         break
-      chunk_size = min(lfcw, _READ_CHUNK_SIZE)
+      chunk_size = min(lfcw - padding_bytes, read_chunk_size)
       bytes_to_send = min(chunk_size, self._send_remaining[stream_id])
-      logging.info('flow_control_window = %d. sending [%d:%d] stream_id %d' %
-                    (lfcw, self._send_offset, self._send_offset + bytes_to_send,
-                    stream_id))
+      logging.info('flow_control_window = %d. sending [%d:%d] stream_id %d. includes %d total padding bytes' %
+                    (lfcw, self._send_offset, self._send_offset + bytes_to_send + padding_bytes,
+                    stream_id, padding_bytes))
+      # The receiver might allow sending frames larger than the http2 minimum
+      # max frame size (16384), but this test should never send more than 16384
+      # for simplicity (which is always legal).
+      if bytes_to_send + padding_bytes > _MIN_SETTINGS_MAX_FRAME_SIZE:
+        raise ValueError("overload: sending %d" % (bytes_to_send + padding_bytes))
       data = self._data_to_send[self._send_offset : self._send_offset + bytes_to_send]
       try:
-        self._conn.send_data(stream_id, data, False)
+        self._conn.send_data(stream_id, data, end_stream=False, pad_length=pad_length)
       except h2.exceptions.ProtocolError:
         logging.info('Stream %d is closed' % stream_id)
         break
@@ -200,5 +209,5 @@ class H2ProtocolBaseServer(twisted.internet.protocol.Protocol):
     req_proto_str = recv_buffer[5:5+grpc_msg_size]
     sr = messages_pb2.SimpleRequest()
     sr.ParseFromString(req_proto_str)
-    logging.info('Parsed request for stream %d: response_size=%s' % (stream_id, sr.response_size))
+    logging.info('Parsed simple request for stream %d' % stream_id)
     return sr
diff --git a/test/http2_test/http2_test_server.py b/test/http2_test/http2_test_server.py
index 46c3e00d18..6a7849b94a 100644
--- a/test/http2_test/http2_test_server.py
+++ b/test/http2_test/http2_test_server.py
@@ -44,6 +44,7 @@ import test_ping
 import test_rst_after_data
 import test_rst_after_header
 import test_rst_during_data
+import test_data_frame_padding
 
 _TEST_CASE_MAPPING = {
   'rst_after_header': test_rst_after_header.TestcaseRstStreamAfterHeader,
@@ -52,6 +53,10 @@ _TEST_CASE_MAPPING = {
   'goaway': test_goaway.TestcaseGoaway,
   'ping': test_ping.TestcasePing,
   'max_streams': test_max_streams.TestcaseSettingsMaxStreams,
+
+  # Positive tests below:
+  'data_frame_padding': test_data_frame_padding.TestDataFramePadding,
+  'no_df_padding_sanity_test': test_data_frame_padding.TestDataFramePadding,
 }
 
 _exit_code = 0
@@ -73,6 +78,8 @@ class H2Factory(twisted.internet.protocol.Factory):
 
     if self._testcase == 'goaway':
       return t(self._num_streams).get_base_server()
+    elif self._testcase == 'no_df_padding_sanity_test':
+      return t(use_padding=False).get_base_server()
     else:
       return t().get_base_server()
 
@@ -81,7 +88,8 @@ def parse_arguments():
   parser.add_argument('--base_port', type=int, default=8080,
     help='base port to run the servers (default: 8080). One test server is '
     'started on each incrementing port, beginning with base_port, in the '
-    'following order: goaway,max_streams,ping,rst_after_data,rst_after_header,'
+    'following order: data_frame_padding,goaway,max_streams,'
+    'no_df_padding_sanity_test,ping,rst_after_data,rst_after_header,'
     'rst_during_data'
     )
   return parser.parse_args()
diff --git a/test/http2_test/test_data_frame_padding.py b/test/http2_test/test_data_frame_padding.py
new file mode 100644
index 0000000000..e1db28faed
--- /dev/null
+++ b/test/http2_test/test_data_frame_padding.py
@@ -0,0 +1,94 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import http2_base_server
+import logging
+import messages_pb2
+
+# Set the number of padding bytes per data frame to be very large
+# relative to the number of data bytes for each data frame sent.
+_LARGE_PADDING_LENGTH = 255
+_SMALL_READ_CHUNK_SIZE = 5
+
+class TestDataFramePadding(object):
+  """
+    In response to an incoming request, this test sends headers, followed by
+    data, followed by a reset stream frame. Client asserts that the RPC failed.
+    Client needs to deliver the complete message to the application layer.
+  """
+  def __init__(self, use_padding=True):
+    self._base_server = http2_base_server.H2ProtocolBaseServer()
+    self._base_server._handlers['DataReceived'] = self.on_data_received
+    self._base_server._handlers['WindowUpdated'] = self.on_window_update
+    self._base_server._handlers['RequestReceived'] = self.on_request_received
+
+    # _total_updates maps stream ids to total flow control updates received
+    self._total_updates = {}
+    # zero window updates so far for connection window (stream id '0')
+    self._total_updates[0] = 0
+    self._read_chunk_size = _SMALL_READ_CHUNK_SIZE
+
+    if use_padding:
+      self._pad_length = _LARGE_PADDING_LENGTH
+    else:
+      self._pad_length = None
+
+  def get_base_server(self):
+    return self._base_server
+
+  def on_data_received(self, event):
+    logging.info('on data received. Stream id: %d. Data length: %d' % (event.stream_id, len(event.data)))
+    self._base_server.on_data_received_default(event)
+    if len(event.data) == 0:
+      return
+    sr = self._base_server.parse_received_data(event.stream_id)
+    stream_bytes = ''
+    # Check if full grpc msg has been read into the recv buffer yet
+    if sr:
+      response_data = self._base_server.default_response_data(sr.response_size)
+      logging.info('Stream id: %d. total resp size: %d' % (event.stream_id, len(response_data)))
+      # Begin sending the response. Add ``self._pad_length`` padding to each
+      # data frame and split the whole message into data frames each carrying
+      # only self._read_chunk_size of data.
+      # The purpose is to have the majority of the data frame response bytes
+      # be padding bytes, since ``self._pad_length`` >> ``self._read_chunk_size``.
+      self._base_server.setup_send(response_data , event.stream_id, pad_length=self._pad_length, read_chunk_size=self._read_chunk_size)
+
+  def on_request_received(self, event):
+    self._base_server.on_request_received_default(event)
+    logging.info('on request received. Stream id: %s.' % event.stream_id)
+    self._total_updates[event.stream_id] = 0
+
+  # Log debug info and try to resume sending on all currently active streams.
+  def on_window_update(self, event):
+    logging.info('on window update. Stream id: %s. Delta: %s' % (event.stream_id, event.delta))
+    self._total_updates[event.stream_id] += event.delta
+    total = self._total_updates[event.stream_id]
+    logging.info('... - total updates for stream %d : %d' % (event.stream_id, total))
+    self._base_server.on_window_update_default(event, pad_length=self._pad_length, read_chunk_size=self._read_chunk_size)
diff --git a/tools/doxygen/Doxyfile.c++ b/tools/doxygen/Doxyfile.c++
index b5021ede15..d21b48cabf 100644
--- a/tools/doxygen/Doxyfile.c++
+++ b/tools/doxygen/Doxyfile.c++
@@ -779,11 +779,11 @@ doc/fail_fast.md \
 doc/g_stands_for.md \
 doc/health-checking.md \
 doc/http-grpc-status-mapping.md \
+doc/http2-interop-test-descriptions.md \
 doc/internationalization.md \
 doc/interop-test-descriptions.md \
 doc/load-balancing.md \
 doc/naming.md \
-doc/negative-http2-interop-test-descriptions.md \
 doc/server-reflection.md \
 doc/server_reflection_tutorial.md \
 doc/server_side_auth.md \
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 758ba2402a..8d6c2838bb 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -779,11 +779,11 @@ doc/fail_fast.md \
 doc/g_stands_for.md \
 doc/health-checking.md \
 doc/http-grpc-status-mapping.md \
+doc/http2-interop-test-descriptions.md \
 doc/internationalization.md \
 doc/interop-test-descriptions.md \
 doc/load-balancing.md \
 doc/naming.md \
-doc/negative-http2-interop-test-descriptions.md \
 doc/server-reflection.md \
 doc/server_reflection_tutorial.md \
 doc/server_side_auth.md \
diff --git a/tools/doxygen/Doxyfile.core b/tools/doxygen/Doxyfile.core
index cd3f2af44c..b4fdcddbcf 100644
--- a/tools/doxygen/Doxyfile.core
+++ b/tools/doxygen/Doxyfile.core
@@ -778,11 +778,11 @@ doc/fail_fast.md \
 doc/g_stands_for.md \
 doc/health-checking.md \
 doc/http-grpc-status-mapping.md \
+doc/http2-interop-test-descriptions.md \
 doc/internationalization.md \
 doc/interop-test-descriptions.md \
 doc/load-balancing.md \
 doc/naming.md \
-doc/negative-http2-interop-test-descriptions.md \
 doc/server-reflection.md \
 doc/server_reflection_tutorial.md \
 doc/server_side_auth.md \
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index b273350082..3e679e3a2b 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -778,11 +778,11 @@ doc/fail_fast.md \
 doc/g_stands_for.md \
 doc/health-checking.md \
 doc/http-grpc-status-mapping.md \
+doc/http2-interop-test-descriptions.md \
 doc/internationalization.md \
 doc/interop-test-descriptions.md \
 doc/load-balancing.md \
 doc/naming.md \
-doc/negative-http2-interop-test-descriptions.md \
 doc/server-reflection.md \
 doc/server_reflection_tutorial.md \
 doc/server_side_auth.md \
diff --git a/tools/internal_ci/linux/grpc_interop_badserver_java.sh b/tools/internal_ci/linux/grpc_interop_badserver_java.sh
index 0985e657c6..c309c623e0 100755
--- a/tools/internal_ci/linux/grpc_interop_badserver_java.sh
+++ b/tools/internal_ci/linux/grpc_interop_badserver_java.sh
@@ -37,5 +37,5 @@ cd $(dirname $0)/../../..
 
 git submodule update --init
 
-tools/run_tests/run_interop_tests.py -l java --use_docker --http2_badserver_interop $@
+tools/run_tests/run_interop_tests.py -l java --use_docker --http2_server_interop $@
 
diff --git a/tools/internal_ci/linux/grpc_interop_badserver_python.sh b/tools/internal_ci/linux/grpc_interop_badserver_python.sh
index 3fff537d2b..c3bb92f33d 100755
--- a/tools/internal_ci/linux/grpc_interop_badserver_python.sh
+++ b/tools/internal_ci/linux/grpc_interop_badserver_python.sh
@@ -37,5 +37,5 @@ cd $(dirname $0)/../../..
 
 git submodule update --init
 
-tools/run_tests/run_interop_tests.py -l python --use_docker --http2_badserver_interop $@
+tools/run_tests/run_interop_tests.py -l python --use_docker --http2_server_interop $@
 
diff --git a/tools/jenkins/run_interop.sh b/tools/jenkins/run_interop.sh
index 2a9fc662a9..13c208e97c 100755
--- a/tools/jenkins/run_interop.sh
+++ b/tools/jenkins/run_interop.sh
@@ -36,4 +36,4 @@ export LANG=en_US.UTF-8
 # Enter the gRPC repo root
 cd $(dirname $0)/../..
 
-tools/run_tests/run_interop_tests.py -l all -s all --cloud_to_prod --cloud_to_prod_auth --use_docker --http2_interop --http2_badserver_interop -t -j 12 $@ || true
+tools/run_tests/run_interop_tests.py -l all -s all --cloud_to_prod --cloud_to_prod_auth --use_docker --http2_interop --http2_server_interop -t -j 12 $@ || true
diff --git a/tools/run_tests/interop/interop_html_report.template b/tools/run_tests/interop/interop_html_report.template
index 88ecd4e4db..6d9de5c62e 100644
--- a/tools/run_tests/interop/interop_html_report.template
+++ b/tools/run_tests/interop/interop_html_report.template
@@ -106,19 +106,19 @@
   % endfor
 % endif
 
-% if http2_badserver_cases:
-  <h2>HTTP/2 Bad Server Tests</h2>
+% if http2_server_cases:
+  <h2>HTTP/2 Server Tests</h2>
   ## Each column header is the client language.
   <table style="width:100%" border="1">
   <tr bgcolor="#00BFFF">
   <th>Client languages &#9658;<br/>Test Cases &#9660;</th>
-  % for client_lang in client_langs_http2_badserver_cases:
+  % for client_lang in client_langs:
     <th>${client_lang}</th>
   % endfor
   </tr>
-  % for test_case in http2_badserver_cases:
+  % for test_case in http2_server_cases:
     <tr><td><b>${test_case}</b></td>
-    % for client_lang in client_langs_http2_badserver_cases:
+    % for client_lang in client_langs:
       <% 
         shortname = 'cloud_to_cloud:%s:http2_server:%s' % (client_lang, 
                                                            test_case)
diff --git a/tools/run_tests/python_utils/report_utils.py b/tools/run_tests/python_utils/report_utils.py
index 131772f55f..3b2b4f8712 100644
--- a/tools/run_tests/python_utils/report_utils.py
+++ b/tools/run_tests/python_utils/report_utils.py
@@ -80,10 +80,9 @@ def render_junit_xml_report(resultset, xml_report, suite_package='grpc',
   tree = ET.ElementTree(root)
   tree.write(xml_report, encoding='UTF-8')
 
-
 def render_interop_html_report(
   client_langs, server_langs, test_cases, auth_test_cases, http2_cases,
-  http2_badserver_cases, client_langs_http2_badserver_cases, resultset, 
+  http2_server_cases, resultset,
   num_failures, cloud_to_prod, prod_servers, http2_interop):
   """Generate HTML report for interop tests."""
   template_file = 'tools/run_tests/interop/interop_html_report.template'
@@ -99,9 +98,7 @@ def render_interop_html_report(
   sorted_test_cases = sorted(test_cases)
   sorted_auth_test_cases = sorted(auth_test_cases)
   sorted_http2_cases = sorted(http2_cases)
-  sorted_http2_badserver_cases = sorted(http2_badserver_cases)
-  sorted_client_langs_http2_badserver_cases = sorted(
-      client_langs_http2_badserver_cases)
+  sorted_http2_server_cases = sorted(http2_server_cases)
   sorted_client_langs = sorted(client_langs)
   sorted_server_langs = sorted(server_langs)
   sorted_prod_servers = sorted(prod_servers)
@@ -111,9 +108,7 @@ def render_interop_html_report(
           'test_cases': sorted_test_cases,
           'auth_test_cases': sorted_auth_test_cases,
           'http2_cases': sorted_http2_cases,
-          'http2_badserver_cases': sorted_http2_badserver_cases,
-          'client_langs_http2_badserver_cases': (
-              sorted_client_langs_http2_badserver_cases),
+          'http2_server_cases': sorted_http2_server_cases,
           'resultset': resultset,
           'num_failures': num_failures,
           'cloud_to_prod': cloud_to_prod,
diff --git a/tools/run_tests/run_interop_tests.py b/tools/run_tests/run_interop_tests.py
index ce4dfb863e..2d7f4a625d 100755
--- a/tools/run_tests/run_interop_tests.py
+++ b/tools/run_tests/run_interop_tests.py
@@ -45,6 +45,7 @@ import tempfile
 import time
 import uuid
 import six
+import traceback
 
 import python_utils.dockerjob as dockerjob
 import python_utils.jobset as jobset
@@ -73,6 +74,10 @@ _SKIP_ADVANCED = ['status_code_and_message',
 
 _TEST_TIMEOUT = 3*60
 
+# disable this test on core-based languages,
+# see https://github.com/grpc/grpc/issues/9779
+_SKIP_DATA_FRAME_PADDING = ['data_frame_padding']
+
 class CXXLanguage:
 
   def __init__(self):
@@ -97,7 +102,7 @@ class CXXLanguage:
     return {}
 
   def unimplemented_test_cases(self):
-    return []
+    return _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return []
@@ -126,7 +131,7 @@ class CSharpLanguage:
     return {}
 
   def unimplemented_test_cases(self):
-    return _SKIP_SERVER_COMPRESSION
+    return _SKIP_SERVER_COMPRESSION + _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return _SKIP_COMPRESSION
@@ -155,7 +160,7 @@ class CSharpCoreCLRLanguage:
     return {}
 
   def unimplemented_test_cases(self):
-    return _SKIP_SERVER_COMPRESSION
+    return _SKIP_SERVER_COMPRESSION + _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return _SKIP_COMPRESSION
@@ -250,7 +255,7 @@ class Http2Server:
     return {}
 
   def unimplemented_test_cases(self):
-    return _TEST_CASES
+    return _TEST_CASES + _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return _TEST_CASES
@@ -281,7 +286,7 @@ class Http2Client:
     return _TEST_CASES
 
   def unimplemented_test_cases_server(self):
-    return []
+    return _TEST_CASES
 
   def __str__(self):
     return 'http2'
@@ -308,7 +313,7 @@ class NodeLanguage:
     return {}
 
   def unimplemented_test_cases(self):
-    return _SKIP_COMPRESSION
+    return _SKIP_COMPRESSION + _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return _SKIP_COMPRESSION
@@ -333,7 +338,7 @@ class PHPLanguage:
     return {}
 
   def unimplemented_test_cases(self):
-    return _SKIP_COMPRESSION
+    return _SKIP_COMPRESSION + _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return []
@@ -358,7 +363,7 @@ class PHP7Language:
     return {}
 
   def unimplemented_test_cases(self):
-    return _SKIP_COMPRESSION
+    return _SKIP_COMPRESSION + _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return []
@@ -389,7 +394,7 @@ class RubyLanguage:
     return {}
 
   def unimplemented_test_cases(self):
-    return _SKIP_SERVER_COMPRESSION
+    return _SKIP_SERVER_COMPRESSION + _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return _SKIP_COMPRESSION
@@ -437,7 +442,7 @@ class PythonLanguage:
             'PYTHONPATH': '{}/src/python/gens'.format(DOCKER_WORKDIR_ROOT)}
 
   def unimplemented_test_cases(self):
-    return _SKIP_COMPRESSION
+    return _SKIP_COMPRESSION + _SKIP_DATA_FRAME_PADDING
 
   def unimplemented_test_cases_server(self):
     return _SKIP_COMPRESSION
@@ -476,10 +481,14 @@ _AUTH_TEST_CASES = ['compute_engine_creds', 'jwt_token_creds',
 
 _HTTP2_TEST_CASES = ['tls', 'framing']
 
-_HTTP2_BADSERVER_TEST_CASES = ['rst_after_header', 'rst_after_data', 'rst_during_data',
-                     'goaway', 'ping', 'max_streams']
+_HTTP2_SERVER_TEST_CASES = ['rst_after_header', 'rst_after_data', 'rst_during_data',
+                               'goaway', 'ping', 'max_streams', 'data_frame_padding', 'no_df_padding_sanity_test']
+
+_GRPC_CLIENT_TEST_CASES_FOR_HTTP2_SERVER_TEST_CASES = { 'data_frame_padding': 'large_unary', 'no_df_padding_sanity_test': 'large_unary' }
 
-_LANGUAGES_FOR_HTTP2_BADSERVER_TESTS = ['java', 'go', 'python', 'c++']
+_HTTP2_SERVER_TEST_CASES_THAT_USE_GRPC_CLIENTS = _GRPC_CLIENT_TEST_CASES_FOR_HTTP2_SERVER_TEST_CASES.keys()
+
+_LANGUAGES_WITH_HTTP2_CLIENTS_FOR_HTTP2_SERVER_TEST_CASES = ['java', 'go', 'python', 'c++']
 
 DOCKER_WORKDIR_ROOT = '/var/local/git/grpc'
 
@@ -631,14 +640,28 @@ def cloud_to_cloud_jobspec(language, test_case, server_name, server_host,
       '--use_tls=%s' % ('false' if insecure else 'true'),
       '--use_test_ca=true',
   ]
+
+  client_test_case = test_case
+  if test_case in _HTTP2_SERVER_TEST_CASES_THAT_USE_GRPC_CLIENTS:
+    client_test_case = _GRPC_CLIENT_TEST_CASES_FOR_HTTP2_SERVER_TEST_CASES[test_case]
+  if client_test_case in language.unimplemented_test_cases():
+    print('asking client %s to run unimplemented test case %s' % (repr(language), client_test_case))
+    sys.exit(1)
+
   common_options = [
-      '--test_case=%s' % test_case,
+      '--test_case=%s' % client_test_case,
       '--server_host=%s' % server_host,
       '--server_port=%s' % server_port,
   ]
-  if test_case in _HTTP2_BADSERVER_TEST_CASES:
-    cmdline = bash_cmdline(language.client_cmd_http2interop(common_options))
-    cwd = language.http2_cwd
+
+  if test_case in _HTTP2_SERVER_TEST_CASES:
+    if test_case in _HTTP2_SERVER_TEST_CASES_THAT_USE_GRPC_CLIENTS:
+      client_options = interop_only_options + common_options
+      cmdline = bash_cmdline(language.client_cmd(client_options))
+      cwd = language.client_cwd
+    else:
+      cmdline = bash_cmdline(language.client_cmd_http2interop(common_options))
+      cwd = language.http2_cwd
   else:
     cmdline = bash_cmdline(language.client_cmd(common_options+interop_only_options))
     cwd = language.client_cwd
@@ -686,7 +709,7 @@ def server_jobspec(language, docker_image, insecure=False, manual_cmd_log=None):
     docker_args += list(
         itertools.chain.from_iterable(('-p', str(_DEFAULT_SERVER_PORT + i))
                                       for i in range(
-                                          len(_HTTP2_BADSERVER_TEST_CASES))))
+                                          len(_HTTP2_SERVER_TEST_CASES))))
     # Enable docker's healthcheck mechanism.
     # This runs a Python script inside the container every second. The script
     # pings the http2 server to verify it is ready. The 'health-retries' flag
@@ -856,11 +879,11 @@ argp.add_argument('--http2_interop',
                   action='store_const',
                   const=True,
                   help='Enable HTTP/2 client edge case testing. (Bad client, good server)')
-argp.add_argument('--http2_badserver_interop',
+argp.add_argument('--http2_server_interop',
                   default=False,
                   action='store_const',
                   const=True,
-                  help='Enable HTTP/2 server edge case testing. (Good client, bad server)')
+                  help='Enable HTTP/2 server edge case testing. (Includes positive and negative tests')
 argp.add_argument('--insecure',
                   default=False,
                   action='store_const',
@@ -895,26 +918,26 @@ languages = set(_LANGUAGES[l]
                     six.iterkeys(_LANGUAGES) if x == 'all' else [x]
                     for x in args.language))
 
-languages_http2_badserver_interop = set()
-if args.http2_badserver_interop:
-  languages_http2_badserver_interop = set(
-      _LANGUAGES[l] for l in _LANGUAGES_FOR_HTTP2_BADSERVER_TESTS
+languages_http2_clients_for_http2_server_interop = set()
+if args.http2_server_interop:
+  languages_http2_clients_for_http2_server_interop = set(
+      _LANGUAGES[l] for l in _LANGUAGES_WITH_HTTP2_CLIENTS_FOR_HTTP2_SERVER_TEST_CASES
       if 'all' in args.language or l in args.language)
 
 http2Interop = Http2Client() if args.http2_interop else None
-http2InteropServer = Http2Server() if args.http2_badserver_interop else None
+http2InteropServer = Http2Server() if args.http2_server_interop else None
 
 docker_images={}
 if args.use_docker:
   # languages for which to build docker images
   languages_to_build = set(
       _LANGUAGES[k] for k in set([str(l) for l in languages] + [s for s in servers]))
-  languages_to_build = languages_to_build | languages_http2_badserver_interop
+  languages_to_build = languages_to_build | languages_http2_clients_for_http2_server_interop
 
   if args.http2_interop:
     languages_to_build.add(http2Interop)
 
-  if args.http2_badserver_interop:
+  if args.http2_server_interop:
     languages_to_build.add(http2InteropServer)
 
   build_jobs = []
@@ -943,7 +966,6 @@ client_manual_cmd_log = [] if args.manual_run else None
 # Start interop servers.
 server_jobs = {}
 server_addresses = {}
-http2_badserver_ports = ()
 try:
   for s in servers:
     lang = str(s)
@@ -957,15 +979,15 @@ try:
       # don't run the server, set server port to a placeholder value
       server_addresses[lang] = ('localhost', '${SERVER_PORT}')
 
-  http2_badserver_job = None
-  if args.http2_badserver_interop:
+  http2_server_job = None
+  if args.http2_server_interop:
     # launch a HTTP2 server emulator that creates edge cases
     lang = str(http2InteropServer)
     spec = server_jobspec(http2InteropServer, docker_images.get(lang),
                           manual_cmd_log=server_manual_cmd_log)
     if not args.manual_run:
-      http2_badserver_job = dockerjob.DockerJob(spec)
-      server_jobs[lang] = http2_badserver_job
+      http2_server_job = dockerjob.DockerJob(spec)
+      server_jobs[lang] = http2_server_job
     else:
       # don't run the server, set server port to a placeholder value
       server_addresses[lang] = ('localhost', '${SERVER_PORT}')
@@ -1049,15 +1071,15 @@ try:
                                           manual_cmd_log=client_manual_cmd_log)
         jobs.append(test_job)
 
-  if args.http2_badserver_interop:
+  if args.http2_server_interop:
     if not args.manual_run:
-      http2_badserver_job.wait_for_healthy(timeout_seconds=600)
-    for language in languages_http2_badserver_interop:
-      for test_case in _HTTP2_BADSERVER_TEST_CASES:
-        offset = sorted(_HTTP2_BADSERVER_TEST_CASES).index(test_case)
+      http2_server_job.wait_for_healthy(timeout_seconds=600)
+    for language in languages_http2_clients_for_http2_server_interop:
+      for test_case in set(_HTTP2_SERVER_TEST_CASES) - set(_HTTP2_SERVER_TEST_CASES_THAT_USE_GRPC_CLIENTS):
+        offset = sorted(_HTTP2_SERVER_TEST_CASES).index(test_case)
         server_port = _DEFAULT_SERVER_PORT+offset
         if not args.manual_run:
-          server_port = http2_badserver_job.mapped_port(server_port)
+          server_port = http2_server_job.mapped_port(server_port)
         test_job = cloud_to_cloud_jobspec(language,
                                           test_case,
                                           str(http2InteropServer),
@@ -1066,6 +1088,31 @@ try:
                                           docker_image=docker_images.get(str(language)),
                                           manual_cmd_log=client_manual_cmd_log)
         jobs.append(test_job)
+    for language in languages:
+      # HTTP2_SERVER_TEST_CASES_THAT_USE_GRPC_CLIENTS is a subset of
+      # HTTP_SERVER_TEST_CASES, in which clients use their gRPC interop clients rather
+      # than specialized http2 clients, reusing existing test implementations.
+      # For example, in the "data_frame_padding" test, use language's gRPC
+      # interop clients and make them think that theyre running "large_unary"
+      # test case. This avoids implementing a new test case in each language.
+      for test_case in _HTTP2_SERVER_TEST_CASES_THAT_USE_GRPC_CLIENTS:
+        if test_case not in language.unimplemented_test_cases():
+          offset = sorted(_HTTP2_SERVER_TEST_CASES).index(test_case)
+          server_port = _DEFAULT_SERVER_PORT+offset
+          if not args.manual_run:
+            server_port = http2_server_job.mapped_port(server_port)
+          if not args.insecure:
+            print(('Creating grpc cient to http2 server test case with insecure connection, even though'
+                   ' args.insecure is False. Http2 test server only supports insecure connections.'))
+          test_job = cloud_to_cloud_jobspec(language,
+                                            test_case,
+                                            str(http2InteropServer),
+                                            'localhost',
+                                            server_port,
+                                            docker_image=docker_images.get(str(language)),
+                                            insecure=True,
+                                            manual_cmd_log=client_manual_cmd_log)
+          jobs.append(test_job)
 
   if not jobs:
     print('No jobs to run.')
@@ -1093,16 +1140,17 @@ try:
     if "http2" in name:
       job[0].http2results = aggregate_http2_results(job[0].message)
 
-  http2_badserver_test_cases = (
-      _HTTP2_BADSERVER_TEST_CASES if args.http2_badserver_interop else [])
+  http2_server_test_cases = (
+      _HTTP2_SERVER_TEST_CASES if args.http2_server_interop else [])
 
   report_utils.render_interop_html_report(
       set([str(l) for l in languages]), servers, _TEST_CASES, _AUTH_TEST_CASES,
-      _HTTP2_TEST_CASES, http2_badserver_test_cases,
-      _LANGUAGES_FOR_HTTP2_BADSERVER_TESTS, resultset, num_failures,
+      _HTTP2_TEST_CASES, http2_server_test_cases, resultset, num_failures,
       args.cloud_to_prod_auth or args.cloud_to_prod, args.prod_servers,
       args.http2_interop)
-
+except Exception as e:
+  print('exception occurred:')
+  traceback.print_exc(file=sys.stdout)
 finally:
   # Check if servers are still running.
   for server, job in server_jobs.items():