http2: support custom SETTINGS parameters

api/envoy/api/v2/core/protocol.proto

@@ -112,8 +112,21 @@ message Http1ProtocolOptions {
   bool enable_trailers = 5;
 }
 
-// [#next-free-field: 13]
+// [#next-free-field: 14]
 message Http2ProtocolOptions {
+  // Defines a parameter to be sent in the SETTINGS frame.
+  // See `RFC7540, sec. 6.5.1 <https://tools.ietf.org/html/rfc7540#section-6.5.1>`_ for details.
+  message SettingsParameter {
+    // The 16 bit parameter identifier.
+    google.protobuf.UInt32Value identifier = 1 [
+      (validate.rules).uint32 = {lte: 65536 gte: 1},
+      (validate.rules).message = {required: true}
+    ];
+
+    // The 32 bit parameter value.
+    google.protobuf.UInt32Value value = 2 [(validate.rules).message = {required: true}];
+  }
+
   // `Maximum table size <https://httpwg.org/specs/rfc7541.html#rfc.section.4.2>`_
   // (in octets) that the encoder is permitted to use for the dynamic HPACK table. Valid values
   // range from 0 to 4294967295 (2^32 - 1) and defaults to 4096. 0 effectively disables header
@@ -216,6 +229,29 @@ message Http2ProtocolOptions {
   //
   // See `RFC7540, sec. 8.1 <https://tools.ietf.org/html/rfc7540#section-8.1>`_ for details.
   bool stream_error_on_invalid_http_messaging = 12;
+
+  // Specifies SETTINGS frame parameters to be sent to the peer, with one exception:
+  // SETTINGS_ENABLE_PUSH (0x2) is not configurable as HTTP/2 server push is not supported by Envoy.
+  //
+  // Note that custom parameters specified through this field may not collide with the following
+  // named parameters:
+  //
+  // .. code-block:: text
+  //
+  //   ID    Field Name
+  //   ----------------
+  //   0x1   hpack_table_size
+  //   0x3   max_concurrent_streams
+  //   0x4   initial_stream_window_size
+  //
+  // Collisions will trigger config validation failure on load/update.
+  // The only exception is '0x8 allow_connect', for which the named parameter field will be
+  // overridden by the value set in this field.
+  //
+  // See `IANA HTTP/2 Settings
+  // <https://www.iana.org/assignments/http2-parameters/http2-parameters.xhtml#settings>`_ for
+  // standardized identifiers.
+  repeated SettingsParameter custom_settings_parameters = 13;
 }
 
 // [#not-implemented-hide:]

api/envoy/config/core/v3/protocol.proto

@@ -128,11 +128,27 @@ message Http1ProtocolOptions {
   bool enable_trailers = 5;
 }
 
-// [#next-free-field: 13]
+// [#next-free-field: 14]
 message Http2ProtocolOptions {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.api.v2.core.Http2ProtocolOptions";
 
+  // Defines a parameter to be sent in the SETTINGS frame.
+  // See `RFC7540, sec. 6.5.1 <https://tools.ietf.org/html/rfc7540#section-6.5.1>`_ for details.
+  message SettingsParameter {
+    option (udpa.annotations.versioning).previous_message_type =
+        "envoy.api.v2.core.Http2ProtocolOptions.SettingsParameter";
+
+    // The 16 bit parameter identifier.
+    google.protobuf.UInt32Value identifier = 1 [
+      (validate.rules).uint32 = {lte: 65536 gte: 1},
+      (validate.rules).message = {required: true}
+    ];
+
+    // The 32 bit parameter value.
+    google.protobuf.UInt32Value value = 2 [(validate.rules).message = {required: true}];
+  }
+
   // `Maximum table size <https://httpwg.org/specs/rfc7541.html#rfc.section.4.2>`_
   // (in octets) that the encoder is permitted to use for the dynamic HPACK table. Valid values
   // range from 0 to 4294967295 (2^32 - 1) and defaults to 4096. 0 effectively disables header
@@ -235,6 +251,29 @@ message Http2ProtocolOptions {
   //
   // See `RFC7540, sec. 8.1 <https://tools.ietf.org/html/rfc7540#section-8.1>`_ for details.
   bool stream_error_on_invalid_http_messaging = 12;
+
+  // Specifies SETTINGS frame parameters to be sent to the peer, with one exception:
+  // SETTINGS_ENABLE_PUSH (0x2) is not configurable as HTTP/2 server push is not supported by Envoy.
+  //
+  // Note that custom parameters specified through this field may not collide with the following
+  // named parameters:
+  //
+  // .. code-block:: text
+  //
+  //   ID    Field Name
+  //   ----------------
+  //   0x1   hpack_table_size
+  //   0x3   max_concurrent_streams
+  //   0x4   initial_stream_window_size
+  //
+  // Collisions will trigger config validation failure on load/update.
+  // The only exception is '0x8 allow_connect', for which the named parameter field will be
+  // overridden by the value set in this field.
+  //
+  // See `IANA HTTP/2 Settings
+  // <https://www.iana.org/assignments/http2-parameters/http2-parameters.xhtml#settings>`_ for
+  // standardized identifiers.
+  repeated SettingsParameter custom_settings_parameters = 13;
 }
 
 // [#not-implemented-hide:]

bazel/repositories.bzl

@@ -505,6 +505,11 @@ def _com_google_absl():
         actual = "@com_google_absl//absl/time:time",
     )
 
+    native.bind(
+        name = "abseil_algorithm",
+        actual = "@com_google_absl//absl/algorithm:algorithm",
+    )
+
 def _com_google_protobuf():
     _repository_impl("rules_python")
     _repository_impl(

include/envoy/http/codec.h

@@ -326,78 +326,6 @@ struct Http1Settings {
   HeaderKeyFormat header_key_format_{HeaderKeyFormat::Default};
 };
 
-/**
- * HTTP/2 codec settings
- */
-struct Http2Settings {
-  // TODO(jwfang): support other HTTP/2 settings
-  uint32_t hpack_table_size_{DEFAULT_HPACK_TABLE_SIZE};
-  uint32_t max_concurrent_streams_{DEFAULT_MAX_CONCURRENT_STREAMS};
-  uint32_t initial_stream_window_size_{DEFAULT_INITIAL_STREAM_WINDOW_SIZE};
-  uint32_t initial_connection_window_size_{DEFAULT_INITIAL_CONNECTION_WINDOW_SIZE};
-  bool allow_connect_{DEFAULT_ALLOW_CONNECT};
-  bool allow_metadata_{DEFAULT_ALLOW_METADATA};
-  bool stream_error_on_invalid_http_messaging_{DEFAULT_STREAM_ERROR_ON_INVALID_HTTP_MESSAGING};
-  uint32_t max_outbound_frames_{DEFAULT_MAX_OUTBOUND_FRAMES};
-  uint32_t max_outbound_control_frames_{DEFAULT_MAX_OUTBOUND_CONTROL_FRAMES};
-  uint32_t max_consecutive_inbound_frames_with_empty_payload_{
-      DEFAULT_MAX_CONSECUTIVE_INBOUND_FRAMES_WITH_EMPTY_PAYLOAD};
-  uint32_t max_inbound_priority_frames_per_stream_{DEFAULT_MAX_INBOUND_PRIORITY_FRAMES_PER_STREAM};
-  uint32_t max_inbound_window_update_frames_per_data_frame_sent_{
-      DEFAULT_MAX_INBOUND_WINDOW_UPDATE_FRAMES_PER_DATA_FRAME_SENT};
-
-  // disable HPACK compression
-  static const uint32_t MIN_HPACK_TABLE_SIZE = 0;
-  // initial value from HTTP/2 spec, same as NGHTTP2_DEFAULT_HEADER_TABLE_SIZE from nghttp2
-  static const uint32_t DEFAULT_HPACK_TABLE_SIZE = (1 << 12);
-  // no maximum from HTTP/2 spec, use unsigned 32-bit maximum
-  static const uint32_t MAX_HPACK_TABLE_SIZE = std::numeric_limits<uint32_t>::max();
-
-  // TODO(jwfang): make this 0, the HTTP/2 spec minimum
-  static const uint32_t MIN_MAX_CONCURRENT_STREAMS = 1;
-  // defaults to maximum, same as nghttp2
-  static const uint32_t DEFAULT_MAX_CONCURRENT_STREAMS = (1U << 31) - 1;
-  // no maximum from HTTP/2 spec, total streams is unsigned 32-bit maximum,
-  // one-side (client/server) is half that, and we need to exclude stream 0.
-  // same as NGHTTP2_INITIAL_MAX_CONCURRENT_STREAMS from nghttp2
-  static const uint32_t MAX_MAX_CONCURRENT_STREAMS = (1U << 31) - 1;
-
-  // initial value from HTTP/2 spec, same as NGHTTP2_INITIAL_WINDOW_SIZE from nghttp2
-  // NOTE: we only support increasing window size now, so this is also the minimum
-  // TODO(jwfang): make this 0 to support decrease window size
-  static const uint32_t MIN_INITIAL_STREAM_WINDOW_SIZE = (1 << 16) - 1;
-  // initial value from HTTP/2 spec is 65535, but we want more (256MiB)
-  static const uint32_t DEFAULT_INITIAL_STREAM_WINDOW_SIZE = 256 * 1024 * 1024;
-  // maximum from HTTP/2 spec, same as NGHTTP2_MAX_WINDOW_SIZE from nghttp2
-  static const uint32_t MAX_INITIAL_STREAM_WINDOW_SIZE = (1U << 31) - 1;
-
-  // CONNECTION_WINDOW_SIZE is similar to STREAM_WINDOW_SIZE, but for connection-level window
-  // TODO(jwfang): make this 0 to support decrease window size
-  static const uint32_t MIN_INITIAL_CONNECTION_WINDOW_SIZE = (1 << 16) - 1;
-  // nghttp2's default connection-level window equals to its stream-level,
-  // our default connection-level window also equals to our stream-level
-  static const uint32_t DEFAULT_INITIAL_CONNECTION_WINDOW_SIZE = 256 * 1024 * 1024;
-  static const uint32_t MAX_INITIAL_CONNECTION_WINDOW_SIZE = (1U << 31) - 1;
-  // By default both nghttp2 and Envoy do not allow CONNECT over H2.
-  static const bool DEFAULT_ALLOW_CONNECT = false;
-  // By default Envoy does not allow METADATA support.
-  static const bool DEFAULT_ALLOW_METADATA = false;
-  // By default Envoy does not allow invalid headers.
-  static const bool DEFAULT_STREAM_ERROR_ON_INVALID_HTTP_MESSAGING = false;
-
-  // Default limit on the number of outbound frames of all types.
-  static const uint32_t DEFAULT_MAX_OUTBOUND_FRAMES = 10000;
-  // Default limit on the number of outbound frames of types PING, SETTINGS and RST_STREAM.
-  static const uint32_t DEFAULT_MAX_OUTBOUND_CONTROL_FRAMES = 1000;
-  // Default limit on the number of consecutive inbound frames with an empty payload
-  // and no end stream flag.
-  static const uint32_t DEFAULT_MAX_CONSECUTIVE_INBOUND_FRAMES_WITH_EMPTY_PAYLOAD = 1;
-  // Default limit on the number of inbound frames of type PRIORITY (per stream).
-  static const uint32_t DEFAULT_MAX_INBOUND_PRIORITY_FRAMES_PER_STREAM = 100;
-  // Default limit on the number of inbound frames of type WINDOW_UPDATE (per DATA frame sent).
-  static const uint32_t DEFAULT_MAX_INBOUND_WINDOW_UPDATE_FRAMES_PER_DATA_FRAME_SENT = 10;
-};
-
 /**
  * A connection (client or server) that owns multiple streams.
  */

include/envoy/upstream/upstream.h

@@ -720,10 +720,11 @@ class ClusterInfo {
   virtual const Http::Http1Settings& http1Settings() const PURE;
 
   /**
-   * @return const Http::Http2Settings& for HTTP/2 connections created on behalf of this cluster.
-   *         @see Http::Http2Settings.
+   * @return const envoy::config::core::v3::Http2ProtocolOptions& for HTTP/2 connections
+   * created on behalf of this cluster.
+   *         @see envoy::config::core::v3::Http2ProtocolOptions.
    */
-  virtual const Http::Http2Settings& http2Settings() const PURE;
+  virtual const envoy::config::core::v3::Http2ProtocolOptions& http2Options() const PURE;
 
   /**
    * @param name std::string containing the well-known name of the extension for which protocol

source/common/http/BUILD

@@ -327,6 +327,7 @@ envoy_cc_library(
     external_deps = [
         "abseil_optional",
         "http_parser",
+        "nghttp2",
     ],
     deps = [
         ":exception_lib",

source/common/http/codec_client.cc

@@ -155,7 +155,7 @@ CodecClientProd::CodecClientProd(Type type, Network::ClientConnectionPtr&& conne
   }
   case Type::HTTP2: {
     codec_ = std::make_unique<Http2::ClientConnectionImpl>(
-        *connection_, *this, host->cluster().statsScope(), host->cluster().http2Settings(),
+        *connection_, *this, host->cluster().statsScope(), host->cluster().http2Options(),
         Http::DEFAULT_MAX_REQUEST_HEADERS_KB, host->cluster().maxResponseHeadersCount());
     break;
   }

source/common/http/conn_manager_utility.cc

@@ -43,11 +43,11 @@ std::string ConnectionManagerUtility::determineNextProtocol(Network::Connection&
 ServerConnectionPtr ConnectionManagerUtility::autoCreateCodec(
     Network::Connection& connection, const Buffer::Instance& data,
     ServerConnectionCallbacks& callbacks, Stats::Scope& scope, const Http1Settings& http1_settings,
-    const Http2Settings& http2_settings, uint32_t max_request_headers_kb,
-    uint32_t max_request_headers_count) {
+    const envoy::config::core::v3::Http2ProtocolOptions& http2_options,
+    uint32_t max_request_headers_kb, uint32_t max_request_headers_count) {
   if (determineNextProtocol(connection, data) == Http2::ALPN_STRING) {
     return std::make_unique<Http2::ServerConnectionImpl>(connection, callbacks, scope,
-                                                         http2_settings, max_request_headers_kb,
+                                                         http2_options, max_request_headers_kb,
                                                          max_request_headers_count);
   } else {
     return std::make_unique<Http1::ServerConnectionImpl>(connection, scope, callbacks,

source/common/http/conn_manager_utility.h

@@ -36,7 +36,8 @@ class ConnectionManagerUtility {
   static ServerConnectionPtr
   autoCreateCodec(Network::Connection& connection, const Buffer::Instance& data,
                   ServerConnectionCallbacks& callbacks, Stats::Scope& scope,
-                  const Http1Settings& http1_settings, const Http2Settings& http2_settings,
+                  const Http1Settings& http1_settings,
+                  const envoy::config::core::v3::Http2ProtocolOptions& http2_options,
                   uint32_t max_request_headers_kb, uint32_t max_request_headers_count);
 
   /**

source/common/http/http2/BUILD

@@ -15,6 +15,8 @@ envoy_cc_library(
     external_deps = [
         "nghttp2",
         "abseil_optional",
+        "abseil_inlined_vector",
+        "abseil_algorithm",
     ],
     deps = [
         ":metadata_decoder_lib",