commit 9a0e1bdda297503fb837318fc459c09b89027490
author fayang <fayang@google.com> Wed Feb 19 13:13:04 2020 -0800
committer Copybara-Service <copybara-worker@google.com> Wed Feb 19 13:13:31 2020 -0800
tree 31da62b191c15acc88a35872edcf1a1b1a10f3fe
parent 5d92c4114bd0fc474b7e95536c303b8e717a2782

gfe-relnote: In QUIC, when arming PTO timer, ignore application data until handshake completes rather than handshake confirmed. Not affecting prod, not protected.

Also refactor GetEarliestPacketSentTimeForPto to make the code cleaner.

PiperOrigin-RevId: 296039749
Change-Id: I6ed4507a5126cc641dc09259830f2b0ce2f1012f

quic/core/quic_sent_packet_manager.cc

diff --git a/quic/core/quic_sent_packet_manager.cc b/quic/core/quic_sent_packet_manager.cc
index 92e6e84..e4f46d8 100644
--- a/quic/core/quic_sent_packet_manager.cc
+++ b/quic/core/quic_sent_packet_manager.cc
@@ -104,7 +104,8 @@
       pto_exponential_backoff_start_point_(0),
       pto_rttvar_multiplier_(4),
       num_tlp_timeout_ptos_(0),
-      one_rtt_packet_acked_(false) {
+      one_rtt_packet_acked_(false),
+      one_rtt_packet_sent_(false) {
   SetSendAlgorithm(congestion_control_type);
 }
 
@@ -475,24 +476,33 @@
   for (int8_t i = 0; i < NUM_PACKET_NUMBER_SPACES; ++i) {
     const QuicTime sent_time = unacked_packets_.GetLastInFlightPacketSentTime(
         static_cast<PacketNumberSpace>(i));
-    if (!earliest_sent_time.IsInitialized()) {
-      earliest_sent_time = sent_time;
-      *packet_number_space = static_cast<PacketNumberSpace>(i);
+    if (!ShouldArmPtoForApplicationData() && i == APPLICATION_DATA) {
       continue;
     }
-    if (i == APPLICATION_DATA) {
-      // Not arming PTO for application data to prioritize the completion of
-      // handshake.
-      break;
+    if (!sent_time.IsInitialized() || (earliest_sent_time.IsInitialized() &&
+                                       earliest_sent_time <= sent_time)) {
+      continue;
     }
-    if (sent_time.IsInitialized()) {
-      earliest_sent_time = std::min(earliest_sent_time, sent_time);
-      *packet_number_space = static_cast<PacketNumberSpace>(i);
-    }
+    earliest_sent_time = sent_time;
+    *packet_number_space = static_cast<PacketNumberSpace>(i);
   }
+
   return earliest_sent_time;
 }
 
+bool QuicSentPacketManager::ShouldArmPtoForApplicationData() const {
+  DCHECK(supports_multiple_packet_number_spaces());
+  // Application data must be ignored before handshake completes (1-RTT key
+  // is available). Not arming PTO for application data to prioritize the
+  // completion of handshake. On the server side, handshake_finished_
+  // indicates handshake complete (and confirmed). On the client side,
+  // one_rtt_packet_sent_ indicates handshake complete (while handshake
+  // confirmation will happen later).
+  return handshake_finished_ ||
+         (unacked_packets_.perspective() == Perspective::IS_CLIENT &&
+          one_rtt_packet_sent_);
+}
+
 void QuicSentPacketManager::MarkForRetransmission(
     QuicPacketNumber packet_number,
     TransmissionType transmission_type) {
@@ -635,6 +645,10 @@
         serialized_packet->encrypted_length, has_retransmittable_data);
   }
 
+  if (serialized_packet->encryption_level == ENCRYPTION_FORWARD_SECURE) {
+    one_rtt_packet_sent_ = true;
+  }
+
   unacked_packets_.AddSentPacket(serialized_packet, transmission_type,
                                  sent_time, in_flight);
   // Reset the retransmission timer anytime a pending packet is sent.