http/2: use hpack_table_size to control both encoder and decoder.

docs/root/intro/version_history.rst

@@ -18,16 +18,18 @@ Version history
   <envoy_api_field_route.RouteAction.idle_timeout>`. This defaults to 5 minutes; if you have
   other timeouts (e.g. connection idle timeout, upstream response per-retry) that are longer than
   this in duration, you may want to consider setting a non-default per-stream idle timeout.
+* http: added generic :ref:`Upgrade support 
+  <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.upgrade_configs>`.
 * http: better handling of HEAD requests. Now sending transfer-encoding: chunked rather than content-length: 0.
 * http: response filters not applied to early error paths such as http_parser generated 400s.
-* proxy_protocol: added support for HAProxy Proxy Protocol v2 (AF_INET/AF_INET6 only).
-* http: added generic +:ref:`Upgrade support 
-  <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.upgrade_configs>`
+* http: :ref:`hpack_table_size <envoy_api_field_core.Http2ProtocolOptions.hpack_table_size>` now controls
+  dynamic table size of both: encoder and decoder.
 * listeners: added the ability to match :ref:`FilterChain <envoy_api_msg_listener.FilterChain>` using
   :ref:`destination_port <envoy_api_field_listener.FilterChainMatch.destination_port>` and
   :ref:`prefix_ranges <envoy_api_field_listener.FilterChainMatch.prefix_ranges>`.
 * lua: added :ref:`connection() <config_http_filters_lua_connection_wrapper>` wrapper and *ssl()* API.
 * lua: added :ref:`requestInfo() <config_http_filters_lua_request_info_wrapper>` wrapper and *protocol()* API.
+* proxy_protocol: added support for HAProxy Proxy Protocol v2 (AF_INET/AF_INET6 only).
 * ratelimit: added support for :repo:`api/envoy/service/ratelimit/v2/rls.proto`.
   Lyft's reference implementation of the `ratelimit <https://github.com/lyft/ratelimit>`_ service also supports the data-plane-api proto as of v1.1.0.
   Envoy can use either proto to send client requests to a ratelimit server with the use of the

source/common/http/http2/codec_impl.cc

@@ -37,7 +37,6 @@ bool Utility::reconstituteCrumbledCookies(const HeaderString& key, const HeaderS
 }
 
 ConnectionImpl::Http2Callbacks ConnectionImpl::http2_callbacks_;
-ConnectionImpl::Http2Options ConnectionImpl::http2_options_;
 
 /**
  * Helper to remove const during a cast. nghttp2 takes non-const pointers for headers even though
@@ -723,14 +722,18 @@ ConnectionImpl::Http2Callbacks::Http2Callbacks() {
 
 ConnectionImpl::Http2Callbacks::~Http2Callbacks() { nghttp2_session_callbacks_del(callbacks_); }
 
-ConnectionImpl::Http2Options::Http2Options() {
+ConnectionImpl::Http2Options::Http2Options(const Http2Settings& http2_settings) {
   nghttp2_option_new(&options_);
   // Currently we do not do anything with stream priority. Setting the following option prevents
   // nghttp2 from keeping around closed streams for use during stream priority dependency graph
   // calculations. This saves a tremendous amount of memory in cases where there are a large number
   // of kept alive HTTP/2 connections.
   nghttp2_option_set_no_closed_streams(options_, 1);
   nghttp2_option_set_no_auto_window_update(options_, 1);
+
+  if (http2_settings.hpack_table_size_ != NGHTTP2_DEFAULT_HEADER_TABLE_SIZE) {
+    nghttp2_option_set_max_deflate_dynamic_table_size(options_, http2_settings.hpack_table_size_);
+  }
 }
 
 ConnectionImpl::Http2Options::~Http2Options() { nghttp2_option_del(options_); }
@@ -739,8 +742,9 @@ ClientConnectionImpl::ClientConnectionImpl(Network::Connection& connection,
                                            Http::ConnectionCallbacks& callbacks,
                                            Stats::Scope& stats, const Http2Settings& http2_settings)
     : ConnectionImpl(connection, stats, http2_settings), callbacks_(callbacks) {
+  Http2Options http2_options(http2_settings);
   nghttp2_session_client_new2(&session_, http2_callbacks_.callbacks(), base(),
-                              http2_options_.options());
+                              http2_options.options());
   sendSettings(http2_settings, true);
 }
 
@@ -784,8 +788,9 @@ ServerConnectionImpl::ServerConnectionImpl(Network::Connection& connection,
                                            Http::ServerConnectionCallbacks& callbacks,
                                            Stats::Scope& scope, const Http2Settings& http2_settings)
     : ConnectionImpl(connection, scope, http2_settings), callbacks_(callbacks) {
+  Http2Options http2_options(http2_settings);
   nghttp2_session_server_new2(&session_, http2_callbacks_.callbacks(), base(),
-                              http2_options_.options());
+                              http2_options.options());
   sendSettings(http2_settings, false);
 }
 

source/common/http/http2/codec_impl.h

@@ -118,7 +118,7 @@ class ConnectionImpl : public virtual Connection, protected Logger::Loggable<Log
    */
   class Http2Options {
   public:
-    Http2Options();
+    Http2Options(const Http2Settings& http2_settings);
     ~Http2Options();
 
     const nghttp2_option* options() { return options_; }

test/common/http/http2/codec_impl_test.cc

@@ -753,6 +753,34 @@ TEST_P(Http2CodecImplTest, TestCodecHeaderLimits) {
   request_encoder_->encodeHeaders(request_headers, false);
 }
 
+TEST_P(Http2CodecImplTest, TestCodecHeaderCompression) {
+  initialize();
+
+  TestHeaderMapImpl request_headers;
+  HttpTestUtility::addDefaultHeaders(request_headers);
+  EXPECT_CALL(request_decoder_, decodeHeaders_(_, true));
+  request_encoder_->encodeHeaders(request_headers, true);
+
+  TestHeaderMapImpl response_headers{{":status", "200"}, {"compression", "test"}};
+  EXPECT_CALL(response_decoder_, decodeHeaders_(_, true));
+  response_encoder_->encodeHeaders(response_headers, true);
+
+  // Sanity check to verify that state of encoders and decoders matches.
+  EXPECT_EQ(nghttp2_session_get_hd_deflate_dynamic_table_size(server_.session()),
+            nghttp2_session_get_hd_inflate_dynamic_table_size(client_.session()));
+  EXPECT_EQ(nghttp2_session_get_hd_deflate_dynamic_table_size(client_.session()),
+            nghttp2_session_get_hd_inflate_dynamic_table_size(server_.session()));
+
+  // Verify that headers are compressed only when both client and server advertise table size > 0:
+  if (client_http2settings_.hpack_table_size_ && server_http2settings_.hpack_table_size_) {
+    EXPECT_NE(0, nghttp2_session_get_hd_deflate_dynamic_table_size(client_.session()));
+    EXPECT_NE(0, nghttp2_session_get_hd_deflate_dynamic_table_size(server_.session()));
+  } else {
+    EXPECT_EQ(0, nghttp2_session_get_hd_deflate_dynamic_table_size(client_.session()));
+    EXPECT_EQ(0, nghttp2_session_get_hd_deflate_dynamic_table_size(server_.session()));
+  }
+}
+
 } // namespace Http2
 } // namespace Http
 } // namespace Envoy