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

quic/test_tools/quic_connection_peer.cc

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