Limits only 16 new QUIC connections can be opened per epoll event.

net/quic/core/quic_buffered_packet_store_test.cc

Index: net/quic/core/quic_buffered_packet_store_test.cc
diff --git a/net/quic/core/quic_buffered_packet_store_test.cc b/net/quic/core/quic_buffered_packet_store_test.cc
index 53cbe0c132d78e9209c05c784ed7510129303f4d..9bce74c45f0d52a190653c41147f3a55eaac04db 100644
--- a/net/quic/core/quic_buffered_packet_store_test.cc
+++ b/net/quic/core/quic_buffered_packet_store_test.cc
@@ -23,6 +23,8 @@ typedef QuicBufferedPacketStore::BufferedPacket BufferedPacket;
 typedef QuicBufferedPacketStore::EnqueuePacketResult EnqueuePacketResult;
 
 static const size_t kDefaultMaxConnectionsInStore = 100;
+static const size_t kMaxConnectionsWithoutCHLO =
+    kDefaultMaxConnectionsInStore / 2;
 
 namespace test {
 namespace {
@@ -70,8 +72,8 @@ class QuicBufferedPacketStoreTest : public ::testing::Test {
 
 TEST_F(QuicBufferedPacketStoreTest, SimpleEnqueueAndDeliverPacket) {
   QuicConnectionId connection_id = 1;
-  store_.EnqueuePacket(connection_id, packet_, server_address_,
-                       client_address_);
+  store_.EnqueuePacket(connection_id, packet_, server_address_, client_address_,
+                       false);
   EXPECT_TRUE(store_.HasBufferedPackets(connection_id));
   list<BufferedPacket> queue = store_.DeliverPackets(connection_id);
   ASSERT_EQ(1u, queue.size());
@@ -88,10 +90,10 @@ TEST_F(QuicBufferedPacketStoreTest, SimpleEnqueueAndDeliverPacket) {
 TEST_F(QuicBufferedPacketStoreTest, DifferentPacketAddressOnOneConnection) {
   IPEndPoint addr_with_new_port(Loopback4(), 256);
   QuicConnectionId connection_id = 1;
+  store_.EnqueuePacket(connection_id, packet_, server_address_, client_address_,
+                       false);
   store_.EnqueuePacket(connection_id, packet_, server_address_,
-                       client_address_);
-  store_.EnqueuePacket(connection_id, packet_, server_address_,
-                       addr_with_new_port);
+                       addr_with_new_port, false);
   list<BufferedPacket> queue = store_.DeliverPackets(connection_id);
   ASSERT_EQ(2u, queue.size());
   // The address migration path should be preserved.
@@ -105,9 +107,9 @@ TEST_F(QuicBufferedPacketStoreTest,
   for (QuicConnectionId connection_id = 1; connection_id <= num_connections;
        ++connection_id) {
     store_.EnqueuePacket(connection_id, packet_, server_address_,
-                         client_address_);
+                         client_address_, false);
     store_.EnqueuePacket(connection_id, packet_, server_address_,
-                         client_address_);
+                         client_address_, false);
   }
 
   // Deliver packets in reversed order.
@@ -124,10 +126,17 @@ TEST_F(QuicBufferedPacketStoreTest,
   // buffered.
   size_t num_packets = kDefaultMaxUndecryptablePackets + 1;
   QuicConnectionId connection_id = 1;
+  if (FLAGS_quic_limit_num_new_sessions_per_epoll_loop) {
+    // Arrived CHLO packet shouldn't affect how many non-CHLO pacekts store can
+    // keep.
+    EXPECT_EQ(QuicBufferedPacketStore::SUCCESS,
+              store_.EnqueuePacket(connection_id, packet_, server_address_,
+                                   client_address_, true));
+  }
   for (size_t i = 1; i <= num_packets; ++i) {
     // Only first |kDefaultMaxUndecryptablePackets packets| will be buffered.
     EnqueuePacketResult result = store_.EnqueuePacket(
-        connection_id, packet_, server_address_, client_address_);
+        connection_id, packet_, server_address_, client_address_, false);
     if (i <= kDefaultMaxUndecryptablePackets) {
       EXPECT_EQ(EnqueuePacketResult::SUCCESS, result);
     } else {
@@ -135,32 +144,40 @@ TEST_F(QuicBufferedPacketStoreTest,
     }
   }
 
-  // Only first |kDefaultMaxUndecryptablePackets| packets are kept in the store
-  // and can be delivered.
-  EXPECT_EQ(kDefaultMaxUndecryptablePackets,
+  // Only first |kDefaultMaxUndecryptablePackets| non-CHLO packets and CHLO are
+  // buffered.
+  EXPECT_EQ(kDefaultMaxUndecryptablePackets +
+                (FLAGS_quic_limit_num_new_sessions_per_epoll_loop ? 1 : 0),
             store_.DeliverPackets(connection_id).size());
 }
 
-TEST_F(QuicBufferedPacketStoreTest, FailToBufferPacketsForTooManyConnections) {
+TEST_F(QuicBufferedPacketStoreTest, ReachNonChloConnectionUpperLimit) {
   // Tests that store can only keep early arrived packets for limited number of
   // connections.
-  size_t num_connections = kDefaultMaxConnectionsInStore + 1;
-  for (size_t connection_id = 1; connection_id <= num_connections;
+  const size_t kNumConnections =
+      (FLAGS_quic_limit_num_new_sessions_per_epoll_loop
+           ? kMaxConnectionsWithoutCHLO
+           : kDefaultMaxConnectionsInStore) +
+      1;
+  for (size_t connection_id = 1; connection_id <= kNumConnections;
        ++connection_id) {
     EnqueuePacketResult result = store_.EnqueuePacket(
-        connection_id, packet_, server_address_, client_address_);
-    if (connection_id <= kDefaultMaxConnectionsInStore) {
+        connection_id, packet_, server_address_, client_address_, false);
+    if (connection_id <= (FLAGS_quic_limit_num_new_sessions_per_epoll_loop
+                              ? kMaxConnectionsWithoutCHLO
+                              : kDefaultMaxConnectionsInStore)) {
       EXPECT_EQ(EnqueuePacketResult::SUCCESS, result);
     } else {
       EXPECT_EQ(EnqueuePacketResult::TOO_MANY_CONNECTIONS, result);
     }
   }
-  // Store only keeps early arrived packets upto |kDefaultMaxConnectionsInStore|
-  // connections.
-  for (size_t connection_id = 1; connection_id <= num_connections;
+  // Store only keeps early arrived packets upto |kNumConnections| connections.
+  for (size_t connection_id = 1; connection_id <= kNumConnections;
        ++connection_id) {
     list<BufferedPacket> queue = store_.DeliverPackets(connection_id);
-    if (connection_id <= kDefaultMaxConnectionsInStore) {
+    if (connection_id <= (FLAGS_quic_limit_num_new_sessions_per_epoll_loop
+                              ? kMaxConnectionsWithoutCHLO
+                              : kDefaultMaxConnectionsInStore)) {
       EXPECT_EQ(1u, queue.size());
     } else {
       EXPECT_EQ(0u, queue.size());
@@ -168,10 +185,91 @@ TEST_F(QuicBufferedPacketStoreTest, FailToBufferPacketsForTooManyConnections) {
   }
 }
 
-TEST_F(QuicBufferedPacketStoreTest, PacketQueueExpiredBeforeDelivery) {
+TEST_F(QuicBufferedPacketStoreTest,
+       FullStoreFailToBufferDataPacketOnNewConnection) {
+  FLAGS_quic_limit_num_new_sessions_per_epoll_loop = true;
+  // Send enough CHLOs so that store gets full before number of connections
+  // without CHLO reaches its upper limit.
+  size_t num_chlos =
+      kDefaultMaxConnectionsInStore - kMaxConnectionsWithoutCHLO + 1;
+  for (size_t connection_id = 1; connection_id <= num_chlos; ++connection_id) {
+    EXPECT_EQ(EnqueuePacketResult::SUCCESS,
+              store_.EnqueuePacket(connection_id, packet_, server_address_,
+                                   client_address_, true));
+  }
+
+  // Send data packets on another |kMaxConnectionsWithoutCHLO| connections.
+  // Store should only be able to buffer till it's full.
+  for (size_t conn_id = num_chlos + 1;
+       conn_id <= (kDefaultMaxConnectionsInStore + 1); ++conn_id) {
+    EnqueuePacketResult result = store_.EnqueuePacket(
+        conn_id, packet_, server_address_, client_address_, true);
+    if (conn_id <= kDefaultMaxConnectionsInStore) {
+      EXPECT_EQ(EnqueuePacketResult::SUCCESS, result);
+    } else {
+      EXPECT_EQ(EnqueuePacketResult::TOO_MANY_CONNECTIONS, result);
+    }
+  }
+}
+
+TEST_F(QuicBufferedPacketStoreTest, EnqueueChloOnTooManyDifferentConnections) {
+  FLAGS_quic_limit_num_new_sessions_per_epoll_loop = true;
+  // Buffer data packets on different connections upto limit.
+  for (QuicConnectionId conn_id = 1; conn_id <= kMaxConnectionsWithoutCHLO;
+       ++conn_id) {
+    EXPECT_EQ(EnqueuePacketResult::SUCCESS,
+              store_.EnqueuePacket(conn_id, packet_, server_address_,
+                                   client_address_, false));
+  }
+
+  // Buffer CHLOs on other connections till store is full.
+  for (size_t i = kMaxConnectionsWithoutCHLO + 1;
+       i <= kDefaultMaxConnectionsInStore + 1; ++i) {
+    EnqueuePacketResult rs = store_.EnqueuePacket(
+        /*connection_id=*/i, packet_, server_address_, client_address_, true);
+    if (i <= kDefaultMaxConnectionsInStore) {
+      EXPECT_EQ(EnqueuePacketResult::SUCCESS, rs);
+      EXPECT_TRUE(store_.HasChloForConnection(/*connection_id=*/i));
+    } else {
+      // Last CHLO can't be buffered because store is full.
+      EXPECT_EQ(EnqueuePacketResult::TOO_MANY_CONNECTIONS, rs);
+      EXPECT_FALSE(store_.HasChloForConnection(/*connection_id=*/i));
+    }
+  }
+
+  // But buffering a CHLO belonging to a connection already has data packet
+  // buffered in the store should success. This is the connection should be
+  // delivered at last.
+  EXPECT_EQ(EnqueuePacketResult::SUCCESS,
+            store_.EnqueuePacket(/*connection_id=*/1, packet_, server_address_,
+                                 client_address_, true));
+  EXPECT_TRUE(store_.HasChloForConnection(/*connection_id=*/1));
+
+  QuicConnectionId delivered_conn_id;
+  for (size_t i = 0;
+       i < kDefaultMaxConnectionsInStore - kMaxConnectionsWithoutCHLO + 1;
+       ++i) {
+    if (i < kDefaultMaxConnectionsInStore - kMaxConnectionsWithoutCHLO) {
+      // Only CHLO is buffered.
+      EXPECT_EQ(
+          1u,
+          store_.DeliverPacketsForNextConnection(&delivered_conn_id).size());
+      EXPECT_EQ(i + kMaxConnectionsWithoutCHLO + 1, delivered_conn_id);
+    } else {
+      EXPECT_EQ(
+          2u,
+          store_.DeliverPacketsForNextConnection(&delivered_conn_id).size());
+      EXPECT_EQ(1u, delivered_conn_id);
+    }
+  }
+  EXPECT_FALSE(store_.HasChlosBuffered());
+}
+
+TEST_F(QuicBufferedPacketStoreTest, PacketQueueExpiredBeforeDelivery1) {
+  FLAGS_quic_limit_num_new_sessions_per_epoll_loop = false;
   QuicConnectionId connection_id = 1;
-  store_.EnqueuePacket(connection_id, packet_, server_address_,
-                       client_address_);
+  store_.EnqueuePacket(connection_id, packet_, server_address_, client_address_,
+                       false);
   // Packet for another connection arrive 1ms later.
   clock_.AdvanceTime(QuicTime::Delta::FromMilliseconds(1));
   QuicConnectionId connection_id2 = 2;
@@ -179,7 +277,7 @@ TEST_F(QuicBufferedPacketStoreTest, PacketQueueExpiredBeforeDelivery) {
   // connections.
   IPEndPoint another_client_address(Loopback4(), 255);
   store_.EnqueuePacket(connection_id2, packet_, server_address_,
-                       another_client_address);
+                       another_client_address, false);
   // Advance clock to the time when connection 1 expires.
   clock_.AdvanceTime(
       QuicBufferedPacketStorePeer::expiration_alarm(&store_)->deadline() -
@@ -205,9 +303,76 @@ TEST_F(QuicBufferedPacketStoreTest, PacketQueueExpiredBeforeDelivery) {
   // for them to expire.
   QuicConnectionId connection_id3 = 3;
   store_.EnqueuePacket(connection_id3, packet_, server_address_,
-                       client_address_);
+                       client_address_, false);
   store_.EnqueuePacket(connection_id3, packet_, server_address_,
-                       client_address_);
+                       client_address_, false);
+  clock_.AdvanceTime(
+      QuicBufferedPacketStorePeer::expiration_alarm(&store_)->deadline() -
+      clock_.ApproximateNow());
+  alarm_factory_.FireAlarm(
+      QuicBufferedPacketStorePeer::expiration_alarm(&store_));
+  // |last_expired_packet_queue_| should be updated.
+  EXPECT_EQ(2u, visitor_.last_expired_packet_queue_.buffered_packets.size());
+}
+
+// Tests that store expires long-staying connections appropriately for
+// connections both with and without CHLOs.
+TEST_F(QuicBufferedPacketStoreTest, PacketQueueExpiredBeforeDelivery2) {
+  FLAGS_quic_limit_num_new_sessions_per_epoll_loop = true;
+  QuicConnectionId connection_id = 1;
+  store_.EnqueuePacket(connection_id, packet_, server_address_, client_address_,
+                       false);
+  if (FLAGS_quic_limit_num_new_sessions_per_epoll_loop) {
+    EXPECT_EQ(EnqueuePacketResult::SUCCESS,
+              store_.EnqueuePacket(connection_id, packet_, server_address_,
+                                   client_address_, true));
+  }
+  QuicConnectionId connection_id2 = 2;
+  EXPECT_EQ(EnqueuePacketResult::SUCCESS,
+            store_.EnqueuePacket(connection_id2, packet_, server_address_,
+                                 client_address_, false));
+
+  // CHLO on connection 3 arrives 1ms later.
+  clock_.AdvanceTime(QuicTime::Delta::FromMilliseconds(1));
+  QuicConnectionId connection_id3 = 3;
+  // Use different client address to differetiate packets from different
+  // connections.
+  IPEndPoint another_client_address(Any4(), 255);
+  store_.EnqueuePacket(connection_id3, packet_, server_address_,
+                       another_client_address, true);
+
+  // Advance clock to the time when connection 1 and 2 expires.
+  clock_.AdvanceTime(
+      QuicBufferedPacketStorePeer::expiration_alarm(&store_)->deadline() -
+      clock_.ApproximateNow());
+  ASSERT_GE(clock_.ApproximateNow(),
+            QuicBufferedPacketStorePeer::expiration_alarm(&store_)->deadline());
+  // Fire alarm to remove long-staying connection 1 and 2 packets.
+  alarm_factory_.FireAlarm(
+      QuicBufferedPacketStorePeer::expiration_alarm(&store_));
+  EXPECT_EQ(1u, visitor_.last_expired_packet_queue_.buffered_packets.size());
+  EXPECT_FALSE(store_.HasBufferedPackets(connection_id));
+  EXPECT_FALSE(store_.HasBufferedPackets(connection_id2));
+
+  // Try to deliver packets, but packet queue has been removed so no
+  // packets can be returned.
+  ASSERT_EQ(0u, store_.DeliverPackets(connection_id).size());
+  ASSERT_EQ(0u, store_.DeliverPackets(connection_id2).size());
+  QuicConnectionId delivered_conn_id;
+  auto queue = store_.DeliverPacketsForNextConnection(&delivered_conn_id);
+  // Connection 3 is the next to be delivered as connection 1 already expired.
+  EXPECT_EQ(connection_id3, delivered_conn_id);
+  ASSERT_EQ(1u, queue.size());
+  // Packets in connection 3 should use another client address.
+  EXPECT_EQ(another_client_address, queue.front().client_address);
+
+  // Test the alarm is reset by enqueueing 2 packets for 4th connection and wait
+  // for them to expire.
+  QuicConnectionId connection_id4 = 4;
+  store_.EnqueuePacket(connection_id4, packet_, server_address_,
+                       client_address_, false);
+  store_.EnqueuePacket(connection_id4, packet_, server_address_,
+                       client_address_, false);
   clock_.AdvanceTime(
       QuicBufferedPacketStorePeer::expiration_alarm(&store_)->deadline() -
       clock_.ApproximateNow());