commit 9929cc4d7163250d637bccb24a1f9ca05c3e68e0
author QUICHE team <quiche-dev@google.com> Wed Mar 13 08:17:43 2019 -0700
committer Copybara-Service <copybara-worker@google.com> Wed Mar 13 08:18:28 2019 -0700
tree fd6700e7ccb943ee033005231d76d02693a62c64
parent 73e63a7a037c2c50f81ec91749569102b9173b10

gfe-relnote: In QUIC, do not close connection if received an in-order ACK with decreased largest_acked. Protected by gfe2_reloadable_flag_quic_tolerate_reneging.

By dremel, this connection close occurs rarely in prod: https://screenshot.googleplex.com/jZpfvdY4nzk

Largest_acked can decrease currently in IETF QUIC, though that may change: https://github.com/quicwg/base-drafts/issues/2205

PiperOrigin-RevId: 238228491
Change-Id: If7586fb8da192dea4436a5572c76bb7aeb1a3227

quic/core/quic_sent_packet_manager_test.cc

diff --git a/quic/core/quic_sent_packet_manager_test.cc b/quic/core/quic_sent_packet_manager_test.cc
index eb3c6a8..024b4c7 100644
--- a/quic/core/quic_sent_packet_manager_test.cc
+++ b/quic/core/quic_sent_packet_manager_test.cc
@@ -2433,6 +2433,38 @@
   EXPECT_TRUE(manager_.OnAckFrameEnd(clock_.Now()));
 }
 
+TEST_P(QuicSentPacketManagerTest, TolerateReneging) {
+  if (!manager_.tolerate_reneging()) {
+    return;
+  }
+  // Send packets 1 - 20.
+  for (size_t i = 1; i <= 20; ++i) {
+    SendDataPacket(i);
+  }
+  // Ack [5, 7), [10, 12), [15, 17).
+  uint64_t acked1[] = {5, 6, 10, 11, 15, 16};
+  uint64_t lost1[] = {1, 2, 3, 4, 7, 8, 9, 12, 13};
+  ExpectAcksAndLosses(true, acked1, QUIC_ARRAYSIZE(acked1), lost1,
+                      QUIC_ARRAYSIZE(lost1));
+  EXPECT_CALL(notifier_, OnFrameLost(_)).Times(AnyNumber());
+  manager_.OnAckFrameStart(QuicPacketNumber(16), QuicTime::Delta::Infinite(),
+                           clock_.Now());
+  manager_.OnAckRange(QuicPacketNumber(15), QuicPacketNumber(17));
+  manager_.OnAckRange(QuicPacketNumber(10), QuicPacketNumber(12));
+  manager_.OnAckRange(QuicPacketNumber(5), QuicPacketNumber(7));
+  EXPECT_TRUE(manager_.OnAckFrameEnd(clock_.Now()));
+
+  // Making sure reneged ACK does not harm. Ack [4, 8), [9, 13).
+  uint64_t acked2[] = {4, 7, 9, 12};
+  ExpectAcksAndLosses(true, acked2, QUIC_ARRAYSIZE(acked2), nullptr, 0);
+  manager_.OnAckFrameStart(QuicPacketNumber(12), QuicTime::Delta::Infinite(),
+                           clock_.Now());
+  manager_.OnAckRange(QuicPacketNumber(9), QuicPacketNumber(13));
+  manager_.OnAckRange(QuicPacketNumber(4), QuicPacketNumber(8));
+  EXPECT_TRUE(manager_.OnAckFrameEnd(clock_.Now()));
+  EXPECT_EQ(QuicPacketNumber(16), manager_.GetLargestObserved());
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace quic