envoyproxy · abeyad · Mar 12, 2024 · Feb 28, 2024 · Mar 3, 2024 · Mar 4, 2024
diff --git a/changelogs/current.yaml b/changelogs/current.yaml
@@ -64,6 +64,12 @@ minor_behavior_changes:
   change: |
     Add more conversion in the proxy status utility. It can be disabled by the runtime guard
     ``envoy.reloadable_features.proxy_status_mapping_more_core_response_flags``.
+- area: http3
+  change: |
+    Use GRO (Generic Receive Offload) for reading packets from a UDP socket. See
+    https://www.kernel.org/doc/html/next/networking/segmentation-offloads.html for a description of
+    GRO. This behavior change can be reverted by setting
+    ``envoy.reloadable_features.prefer_udp_gro`` to ``false``.
 
 bug_fixes:
 # *Changes expected to improve the state of the world and are unlikely to have negative effects*

diff --git a/source/common/network/utility.cc b/source/common/network/utility.cc
@@ -602,7 +602,6 @@ Api::IoCallUint64Result Utility::readFromSocket(IoHandle& handle,
                                                 UdpPacketProcessor& udp_packet_processor,
                                                 MonotonicTime receive_time, bool use_gro,
                                                 uint32_t* packets_dropped) {
-
   if (use_gro) {
     Buffer::InstancePtr buffer = std::make_unique<Buffer::OwnedImpl>();
     IoHandle::RecvMsgOutput output(1, packets_dropped);

diff --git a/source/common/quic/BUILD b/source/common/quic/BUILD
@@ -362,6 +362,7 @@ envoy_cc_library(
         "//envoy/event:dispatcher_interface",
         "//source/common/network:socket_option_factory_lib",
         "//source/common/network:udp_packet_writer_handler_lib",
+        "//source/common/runtime:runtime_lib",
         "@com_github_google_quiche//:quic_core_connection_lib",
         "@envoy_api//envoy/config/core/v3:pkg_cc_proto",
     ],
@@ -435,6 +436,7 @@ envoy_cc_library(
         "//source/common/network:socket_option_factory_lib",
         "//source/common/protobuf:utility_lib",
         "//source/common/quic:quic_io_handle_wrapper_lib",
+        "//source/common/runtime:runtime_lib",
         "@com_github_google_quiche//:quic_core_config_lib",
         "@com_github_google_quiche//:quic_core_http_header_list_lib",
         "@envoy_api//envoy/config/core/v3:pkg_cc_proto",

diff --git a/source/common/quic/envoy_quic_client_connection.cc b/source/common/quic/envoy_quic_client_connection.cc
@@ -7,6 +7,7 @@
 #include "source/common/network/socket_option_factory.h"
 #include "source/common/network/udp_packet_writer_handler_impl.h"
 #include "source/common/quic/envoy_quic_utils.h"
+#include "source/common/runtime/runtime_features.h"
 
 namespace Envoy {
 namespace Quic {
@@ -229,7 +230,9 @@ void EnvoyQuicClientConnection::onFileEvent(uint32_t events,
   if (connected() && (events & Event::FileReadyType::Read)) {
     Api::IoErrorPtr err = Network::Utility::readPacketsFromSocket(
         connection_socket.ioHandle(), *connection_socket.connectionInfoProvider().localAddress(),
-        *this, dispatcher_.timeSource(), /*prefer_gro=*/false, packets_dropped_);
+        *this, dispatcher_.timeSource(),
+        Runtime::runtimeFeatureEnabled("envoy.reloadable_features.prefer_udp_gro"),
+        packets_dropped_);
     if (err == nullptr) {
       // In the case where the path validation fails, the probing socket will be closed and its IO
       // events are no longer interesting.

diff --git a/source/common/quic/envoy_quic_utils.cc b/source/common/quic/envoy_quic_utils.cc
@@ -5,10 +5,12 @@
 #include "envoy/common/platform.h"
 #include "envoy/config/core/v3/base.pb.h"
 
+#include "source/common/api/os_sys_calls_impl.h"
 #include "source/common/http/utility.h"
 #include "source/common/network/socket_option_factory.h"
 #include "source/common/network/utility.h"
 #include "source/common/protobuf/utility.h"
+#include "source/common/runtime/runtime_features.h"
 
 namespace Envoy {
 namespace Quic {
@@ -149,6 +151,10 @@ createConnectionSocket(const Network::Address::InstanceConstSharedPtr& peer_addr
   }
   connection_socket->addOptions(Network::SocketOptionFactory::buildIpPacketInfoOptions());
   connection_socket->addOptions(Network::SocketOptionFactory::buildRxQueueOverFlowOptions());
+  if (Runtime::runtimeFeatureEnabled("envoy.reloadable_features.prefer_udp_gro") &&
+      Api::OsSysCallsSingleton::get().supportsUdpGro()) {
+    connection_socket->addOptions(Network::SocketOptionFactory::buildUdpGroOptions());
+  }
   if (options != nullptr) {
     connection_socket->addOptions(options);
   }

diff --git a/source/common/runtime/runtime_features.cc b/source/common/runtime/runtime_features.cc
@@ -75,6 +75,7 @@ RUNTIME_GUARD(envoy_reloadable_features_oauth_make_token_cookie_httponly);
 RUNTIME_GUARD(envoy_reloadable_features_oauth_use_standard_max_age_value);
 RUNTIME_GUARD(envoy_reloadable_features_oauth_use_url_encoding);
 RUNTIME_GUARD(envoy_reloadable_features_original_dst_rely_on_idle_timeout);
+RUNTIME_GUARD(envoy_reloadable_features_prefer_udp_gro);
 RUNTIME_GUARD(envoy_reloadable_features_proxy_status_mapping_more_core_response_flags);
 RUNTIME_GUARD(envoy_reloadable_features_proxy_status_upstream_request_timeout);
 RUNTIME_GUARD(envoy_reloadable_features_quic_fix_filter_manager_uaf);

diff --git a/test/common/quic/BUILD b/test/common/quic/BUILD
@@ -191,6 +191,7 @@ envoy_cc_test(
     deps = [
         ":test_utils_lib",
         "//envoy/stats:stats_macros",
+        "//source/common/api:os_sys_calls_lib",
         "//source/common/quic:client_codec_lib",
         "//source/common/quic:envoy_quic_alarm_factory_lib",
         "//source/common/quic:envoy_quic_client_connection_lib",
@@ -203,6 +204,7 @@ envoy_cc_test(
         "//test/mocks/stats:stats_mocks",
         "//test/test_common:logging_lib",
         "//test/test_common:simulated_time_system_lib",
+        "//test/test_common:threadsafe_singleton_injector_lib",
         "@com_github_google_quiche//:quic_test_tools_session_peer_lib",
     ],
 )

diff --git a/test/common/quic/envoy_quic_client_session_test.cc b/test/common/quic/envoy_quic_client_session_test.cc
@@ -1,5 +1,6 @@
 #include "envoy/stats/stats_macros.h"
 
+#include "source/common/api/os_sys_calls_impl.h"
 #include "source/common/network/transport_socket_options_impl.h"
 #include "source/common/quic/client_codec_impl.h"
 #include "source/common/quic/envoy_quic_alarm_factory.h"
@@ -18,6 +19,7 @@
 #include "test/test_common/logging.h"
 #include "test/test_common/network_utility.h"
 #include "test/test_common/simulated_time_system.h"
+#include "test/test_common/threadsafe_singleton_injector.h"
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
@@ -472,5 +474,48 @@ TEST_P(EnvoyQuicClientSessionTest, StatelessResetOnProbingSocket) {
   EXPECT_EQ(self_addr_->asString(), quic_connection_->self_address().ToString());
 }
 
+class MockOsSysCallsImpl : public Api::OsSysCallsImpl {
+public:
+  MOCK_METHOD(Api::SysCallSizeResult, recvmsg, (os_fd_t socket, msghdr* msg, int flags),
+              (override));
+  MOCK_METHOD(Api::SysCallIntResult, recvmmsg,
+              (os_fd_t socket, struct mmsghdr* msgvec, unsigned int vlen, int flags,
+               struct timespec* timeout),
+              (override));
+};
+
+// Ensures that the Network::Utility::readFromSocket function uses GRO instead of `recvmmsg`.
+// Only Linux platforms support GRO.
+#if defined(__linux__)
+TEST_P(EnvoyQuicClientSessionTest, UsesUdpGro) {
+  MockOsSysCallsImpl os_sys_calls_;
+  TestThreadsafeSingletonInjector<Api::OsSysCallsImpl> singleton_injector_{&os_sys_calls_};
+
+  // Have to connect the QUIC session, so that the socket is set up so we can do I/O on it.
+  envoy_quic_session_.connect();
+
+  std::string write_data = "abc";
+  Buffer::RawSlice slice;
+  slice.mem_ = write_data.data();
+  slice.len_ = write_data.length();
+
+  // GRO uses `recvmsg`, not `recvmmsg`.
+  EXPECT_CALL(os_sys_calls_, recvmmsg(_, _, _, _, _)).Times(0);
+  EXPECT_CALL(os_sys_calls_, recvmsg(_, _, _))
+      .WillOnce(
+          Invoke([&](os_fd_t /*socket*/, msghdr* /*msg*/, int /*flags*/) -> Api::SysCallSizeResult {
+            dispatcher_->exit();
+            // Return an error so IoSocketHandleImpl::recvmsg() exits early, instead of trying to
+            // use the msghdr that would normally have been populated by recvmsg but is not
+            // populated by this mock.
+            return {-1, SOCKET_ERROR_AGAIN};
+          }));
+
+  peer_socket_->ioHandle().sendmsg(&slice, 1, 0, peer_addr_->ip(), *self_addr_);
+
+  dispatcher_->run(Event::Dispatcher::RunType::RunUntilExit);
+}
+#endif
+
 } // namespace Quic
 } // namespace Envoy