Make a getPeerTransportParams function

Summary: I'm putting this up to get some initial feedback. I'm writing a function to get the peer transport parameters so that we can get them in the HQSession and set the QUIC fingerprint.

Reviewed By: hanidamlaj

Differential Revision: D54399572

fbshipit-source-id: 594294c26a5b34bc99a8d286a66be9cdbe7fff02

quic/api/QuicSocket.h

@@ -18,6 +18,7 @@
 #include <quic/common/events/QuicEventBase.h>
 #include <quic/common/udpsocket/QuicAsyncUDPSocket.h>
 #include <quic/congestion_control/Bandwidth.h>
+#include <quic/handshake/TransportParameters.h>
 #include <quic/observer/SocketObserverContainer.h>
 #include <quic/observer/SocketObserverTypes.h>
 #include <quic/state/QuicConnectionStats.h>
@@ -277,6 +278,11 @@ class QuicSocket {
     folly::Optional<QuicErrorCode> streamWriteError;
   };
 
+  // Returns folly::none before the handshake is complete, otherwise is always
+  // non-empty.
+  virtual folly::Optional<std::vector<TransportParameter>>
+  getPeerTransportParams() const = 0;
+
   /**
    * Sets connection setup callback. This callback must be set before using the
    * socket.

quic/api/test/MockQuicSocket.h

@@ -51,6 +51,11 @@ class MockQuicSocket : public QuicSocket {
   MOCK_METHOD(const folly::SocketAddress&, getPeerAddress, (), (const));
   MOCK_METHOD(const folly::SocketAddress&, getOriginalPeerAddress, (), (const));
   MOCK_METHOD(const folly::SocketAddress&, getLocalAddress, (), (const));
+  MOCK_METHOD(
+      folly::Optional<std::vector<TransportParameter>>,
+      getPeerTransportParams,
+      (),
+      (const));
   MOCK_METHOD(std::shared_ptr<QuicEventBase>, getEventBase, (), (const));
   MOCK_METHOD(
       (folly::Expected<size_t, LocalErrorCode>),

quic/api/test/QuicTransportBaseTest.cpp

@@ -261,6 +261,11 @@ class TestQuicTransport
     closeUdpSocket();
   }
 
+  folly::Optional<std::vector<TransportParameter>> getPeerTransportParams()
+      const override {
+    return folly::none;
+  }
+
   std::chrono::milliseconds getLossTimeoutRemainingTime() {
     return lossTimeout_.getTimerCallbackTimeRemaining();
   }

quic/api/test/TestQuicTransport.h

@@ -50,6 +50,11 @@ class TestQuicTransport
     closeUdpSocket();
   }
 
+  folly::Optional<std::vector<TransportParameter>> getPeerTransportParams()
+      const override {
+    return folly::none;
+  }
+
   QuicVersion getVersion() {
     auto& conn = getConnectionState();
     return conn.version.value_or(*conn.originalVersion);

quic/client/QuicClientTransport.cpp

@@ -1736,6 +1736,18 @@ void QuicClientTransport::maybeSendTransportKnobs() {
   }
 }
 
+folly::Optional<std::vector<TransportParameter>>
+QuicClientTransport::getPeerTransportParams() const {
+  if (clientConn_ && clientConn_->clientHandshakeLayer) {
+    auto maybeParams =
+        clientConn_->clientHandshakeLayer->getServerTransportParams();
+    if (maybeParams) {
+      return maybeParams->parameters;
+    }
+  }
+  return folly::none;
+}
+
 void QuicClientTransport::RecvmmsgStorage::resize(size_t numPackets) {
   if (msgs.size() != numPackets) {
     msgs.resize(numPackets);

quic/client/QuicClientTransport.h

@@ -201,6 +201,9 @@ class QuicClientTransport
     conn_->bufAccessor = bufAccessor_.get();
   }
 
+  folly::Optional<std::vector<TransportParameter>> getPeerTransportParams()
+      const override;
+
   class HappyEyeballsConnAttemptDelayTimeout : public QuicTimerCallback {
    public:
     explicit HappyEyeballsConnAttemptDelayTimeout(

quic/server/QuicServerTransport.cpp

@@ -1201,4 +1201,16 @@ void QuicServerTransport::logTimeBasedStats() const {
   }
 }
 
+folly::Optional<std::vector<TransportParameter>>
+QuicServerTransport::getPeerTransportParams() const {
+  if (serverConn_ && serverConn_->serverHandshakeLayer) {
+    auto maybeParams =
+        serverConn_->serverHandshakeLayer->getClientTransportParams();
+    if (maybeParams) {
+      return maybeParams->parameters;
+    }
+  }
+  return folly::none;
+}
+
 } // namespace quic

quic/server/QuicServerTransport.h

@@ -168,6 +168,9 @@ class QuicServerTransport
    */
   void logTimeBasedStats() const;
 
+  folly::Optional<std::vector<TransportParameter>> getPeerTransportParams()
+      const override;
+
  protected:
   // From QuicSocket
   SocketObserverContainer* getSocketObserverContainer() const override {

quic/server/handshake/ServerTransportParametersExtension.h

@@ -121,8 +121,8 @@ class ServerTransportParametersExtension : public fizz::ServerExtensions {
     return exts;
   }
 
-  folly::Optional<ClientTransportParameters> getClientTransportParams() {
-    return std::move(clientTransportParameters_);
+  const folly::Optional<ClientTransportParameters>& getClientTransportParams() {
+    return clientTransportParameters_;
   }
 
  private: