Add enableCustomRetransmissionPolicies()

Summary: Add enableCustomRetransmissionPolicies()

Reviewed By: mjoras

Differential Revision: D39658775

fbshipit-source-id: 1413e6a3112e406222df4ce54e6036f518432a82

quic/api/QuicTransportBase.cpp

@@ -3805,10 +3805,17 @@ void QuicTransportBase::onStreamPrioritiesChange() {
   conn_->congestionController->setBandwidthUtilizationFactor(targetUtilization);
 }
 
+bool QuicTransportBase::checkCustomRetransmissionProfilesEnabled() const {
+  return quic::checkCustomRetransmissionProfilesEnabled(*conn_);
+}
+
 folly::Expected<folly::Unit, LocalErrorCode>
 QuicTransportBase::setStreamGroupRetransmissionPolicy(
     StreamGroupId /* groupId */,
     QuicStreamGroupRetransmissionPolicy /* policy */) noexcept {
+  if (!checkCustomRetransmissionProfilesEnabled()) {
+    return folly::makeUnexpected(LocalErrorCode::INVALID_OPERATION);
+  }
   return folly::unit;
 }
 

quic/api/QuicTransportBase.h

@@ -654,6 +654,9 @@ class QuicTransportBase : public QuicSocket, QuicStreamPrioritiesObserver {
 
   void appendCmsgs(const folly::SocketOptionMap& options);
 
+  /**
+   * Sets stream group retransmission policy.
+   */
   folly::Expected<folly::Unit, LocalErrorCode>
   setStreamGroupRetransmissionPolicy(
       StreamGroupId groupId,
@@ -959,6 +962,13 @@ class QuicTransportBase : public QuicSocket, QuicStreamPrioritiesObserver {
    * Helper to log new stream event to observer.
    */
   void logStreamOpenEvent(StreamId streamId);
+
+  /**
+   * Helper to check if using custom retransmission profiles is feasible.
+   * Custom retransmission profiles are only applicable when stream groups are
+   * enabled, i.e. advertisedMaxStreamGroups in transport settings is > 0.
+   */
+  [[nodiscard]] bool checkCustomRetransmissionProfilesEnabled() const;
 };
 
 std::ostream& operator<<(std::ostream& os, const QuicTransportBase& qt);

quic/api/test/QuicTransportBaseTest.cpp

@@ -4430,5 +4430,33 @@ TEST_P(QuicTransportImplTestWithGroups, onNewStreamsAndGroupsCallbacks) {
   transport.reset();
 }
 
+TEST_P(
+    QuicTransportImplTestWithGroups,
+    TestSetStreamGroupRetransmissionPolicyAllowed) {
+  auto transportSettings = transport->getTransportSettings();
+  transportSettings.advertisedMaxStreamGroups = 16;
+  transport->setTransportSettings(transportSettings);
+  transport->getConnectionState().streamManager->refreshTransportSettings(
+      transportSettings);
+
+  const StreamGroupId groupId = 0x00;
+  const QuicStreamGroupRetransmissionPolicy policy;
+
+  // Test policy set allowed
+  auto res = transport->setStreamGroupRetransmissionPolicy(groupId, policy);
+  EXPECT_TRUE(res.hasValue());
+
+  // Test policy set not allowed.
+  transportSettings.advertisedMaxStreamGroups = 0;
+  transport->setTransportSettings(transportSettings);
+  transport->getConnectionState().streamManager->refreshTransportSettings(
+      transportSettings);
+  res = transport->setStreamGroupRetransmissionPolicy(groupId, policy);
+  EXPECT_TRUE(res.hasError());
+  EXPECT_EQ(res.error(), LocalErrorCode::INVALID_OPERATION);
+
+  transport.reset();
+}
+
 } // namespace test
 } // namespace quic

quic/state/QuicStateFunctions.cpp

@@ -432,4 +432,9 @@ uint64_t updateLargestReceivedPacketNum(
   }
 }
 
+bool checkCustomRetransmissionProfilesEnabled(
+    const QuicConnectionStateBase& conn) {
+  return conn.transportSettings.advertisedMaxStreamGroups > 0;
+}
+
 } // namespace quic

quic/state/QuicStateFunctions.h

@@ -110,4 +110,7 @@ std::pair<folly::Optional<TimePoint>, PacketNumberSpace> earliestTimeAndSpace(
 
 uint64_t maximumConnectionIdsToIssue(const QuicConnectionStateBase& conn);
 
+bool checkCustomRetransmissionProfilesEnabled(
+    const QuicConnectionStateBase& conn);
+
 } // namespace quic