gfe-relnote: In QUIC, add anti-amplification limit. Protected by version T099. Anti-amplification limit kicks in before address validation. Now, server can only validate address by processing HANDSHAKE encrypted packet since address validation via token is not implemented. In T099, deprecate HANDSHAKE_MODE and PTO is armed when 1) handshake is not confirmed 2) or there is packets in flight. Such that when PTO fires, at least 1 packet is sent to avoid handshake deadlock due to anti-amplification limit in case of packet losses. PiperOrigin-RevId: 264960590 Change-Id: Ib2d9749b773af9328f96c176a49b2505be006b00

diff --git a/quic/test_tools/crypto_test_utils.cc b/quic/test_tools/crypto_test_utils.cc
index e3e649e..27e47b2 100644
--- a/quic/test_tools/crypto_test_utils.cc
+++ b/quic/test_tools/crypto_test_utils.cc

@@ -692,6 +692,8 @@
     // them into |framer|, perform the decryption with them, and then swap ther
     // back.
     QuicConnectionPeer::SwapCrypters(dest_conn, framer.framer());
+    QuicConnectionPeer::AddBytesReceived(
+        dest_conn, source_conn->encrypted_packets_[index]->length());
     if (!framer.ProcessPacket(*source_conn->encrypted_packets_[index])) {
       // The framer will be unable to decrypt forward-secure packets sent after
       // the handshake is complete. Don't treat them as handshake packets.

diff --git a/quic/test_tools/quic_connection_peer.cc b/quic/test_tools/quic_connection_peer.cc
index 66d1a51..ef2ffb3 100644
--- a/quic/test_tools/quic_connection_peer.cc
+++ b/quic/test_tools/quic_connection_peer.cc

@@ -332,5 +332,18 @@
   connection->last_header_.form = format;
 }
 
+// static
+void QuicConnectionPeer::AddBytesReceived(QuicConnection* connection,
+                                          size_t length) {
+  if (connection->EnforceAntiAmplificationLimit()) {
+    connection->bytes_received_before_address_validation_ += length;
+  }
+}
+
+// static
+void QuicConnectionPeer::SetAddressValidated(QuicConnection* connection) {
+  connection->address_validated_ = true;
+}
+
 }  // namespace test
 }  // namespace quic

diff --git a/quic/test_tools/quic_connection_peer.h b/quic/test_tools/quic_connection_peer.h
index d0797f5..f329a1c 100644
--- a/quic/test_tools/quic_connection_peer.h
+++ b/quic/test_tools/quic_connection_peer.h

@@ -133,6 +133,8 @@
       QuicConnection* connection);
   static void SetLastHeaderFormat(QuicConnection* connection,
                                   PacketHeaderFormat format);
+  static void AddBytesReceived(QuicConnection* connection, size_t length);
+  static void SetAddressValidated(QuicConnection* connection);
 };
 
 }  // namespace test