Landing Recent QUIC Changes.

net/quic/quic_unacked_packet_map.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_unacked_packet_map.h"
 
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "net/quic/quic_connection_stats.h"
 #include "net/quic/quic_utils_chromium.h"
@@ skipping 20 matching lines @@
         index == *it->all_transmissions->rbegin()) {
       delete it->all_transmissions;
     }
   }
 }
 
 // TODO(ianswett): Combine this method with OnPacketSent once packets are always
 // sent in order and the connection tracks RetransmittableFrames for longer.
 void QuicUnackedPacketMap::AddPacket(
     const SerializedPacket& serialized_packet) {
-  DCHECK_EQ(least_unacked_ + unacked_packets_.size(),
-            serialized_packet.sequence_number);
+  DCHECK_GE(serialized_packet.sequence_number,
+            least_unacked_ + unacked_packets_.size());
+  while (least_unacked_ + unacked_packets_.size() <
+         serialized_packet.sequence_number) {
+    unacked_packets_.push_back(TransmissionInfo());
+    unacked_packets_.back().is_unackable = true;
+  }
   unacked_packets_.push_back(
       TransmissionInfo(serialized_packet.retransmittable_frames,
                        serialized_packet.sequence_number_length));
   if (serialized_packet.retransmittable_frames != NULL &&
       serialized_packet.retransmittable_frames->HasCryptoHandshake()
           == IS_HANDSHAKE) {
     ++pending_crypto_packet_count_;
   }
 }
 
 void QuicUnackedPacketMap::RemoveObsoletePackets() {
   while (!unacked_packets_.empty()) {
     if (!IsPacketRemovable(least_unacked_, unacked_packets_.front())) {
       break;
     }
-    delete unacked_packets_.front().all_transmissions;
     unacked_packets_.pop_front();
     ++least_unacked_;
   }
 }
 
 void QuicUnackedPacketMap::OnRetransmittedPacket(
     QuicPacketSequenceNumber old_sequence_number,
     QuicPacketSequenceNumber new_sequence_number,
     TransmissionType transmission_type) {
   DCHECK_GE(old_sequence_number, least_unacked_);
   DCHECK_LT(old_sequence_number, least_unacked_ + unacked_packets_.size());
-  DCHECK_EQ(least_unacked_ + unacked_packets_.size(), new_sequence_number);
+  DCHECK_GE(new_sequence_number, least_unacked_ + unacked_packets_.size());
+  while (least_unacked_ + unacked_packets_.size() < new_sequence_number) {
+    unacked_packets_.push_back(TransmissionInfo());
+    unacked_packets_.back().is_unackable = true;
+  }
 
   // TODO(ianswett): Discard and lose the packet lazily instead of immediately.
   TransmissionInfo* transmission_info =
       &unacked_packets_.at(old_sequence_number - least_unacked_);
   RetransmittableFrames* frames = transmission_info->retransmittable_frames;
   LOG_IF(DFATAL, frames == NULL) << "Attempt to retransmit packet with no "
                                  << "retransmittable frames: "
                                  << old_sequence_number;
 
   // We keep the old packet in the unacked packet list until it, or one of
   // the retransmissions of it are acked.
   transmission_info->retransmittable_frames = NULL;
   // Only keep one transmission older than largest observed, because only the
   // most recent is expected to possibly be a spurious retransmission.
-  if (transmission_info->all_transmissions != NULL &&
-      *(++transmission_info->all_transmissions->begin()) < largest_observed_) {
+  while (transmission_info->all_transmissions != NULL &&
+         transmission_info->all_transmissions->size() > 1 &&
+         *(++transmission_info->all_transmissions->begin())
+             < largest_observed_) {
     QuicPacketSequenceNumber old_transmission =
         *transmission_info->all_transmissions->begin();
     TransmissionInfo* old_info =
         &unacked_packets_[old_transmission - least_unacked_];
     // Don't remove old packets if they're still in flight.
-    if (!old_info->in_flight) {
-      old_info->all_transmissions->pop_front();
-      // This will cause the packet be removed in RemoveObsoletePackets.
-      old_info->all_transmissions = NULL;
+    if (old_info->in_flight) {
+      break;
     }
+    old_info->all_transmissions->pop_front();
+    // This will cause the packet be removed in RemoveObsoletePackets.
+    old_info->all_transmissions = NULL;
   }
-  if (transmission_info->all_transmissions == NULL) {
-    transmission_info->all_transmissions = new SequenceNumberList();
-    transmission_info->all_transmissions->push_back(old_sequence_number);
+  // Don't link old transmissions to new ones when version or
+  // encryption changes.
+  if (transmission_type == ALL_INITIAL_RETRANSMISSION ||
+      transmission_type == ALL_UNACKED_RETRANSMISSION) {
+    RemoveAckability(transmission_info);
+  } else {
+    if (transmission_info->all_transmissions == NULL) {
+      transmission_info->all_transmissions = new SequenceNumberList();
+      transmission_info->all_transmissions->push_back(old_sequence_number);
+    }
+    transmission_info->all_transmissions->push_back(new_sequence_number);
   }
-  transmission_info->all_transmissions->push_back(new_sequence_number);
   unacked_packets_.push_back(
       TransmissionInfo(frames,
                        transmission_info->sequence_number_length,
                        transmission_type,
                        transmission_info->all_transmissions));
+  RemoveObsoletePackets();
 }
 
 void QuicUnackedPacketMap::ClearAllPreviousRetransmissions() {
   while (!unacked_packets_.empty() && least_unacked_ < largest_observed_) {
     // If this packet is in flight, or has retransmittable data, then there is
     // no point in clearing out any further packets, because they would not
     // affect the high water mark.
     TransmissionInfo* info = &unacked_packets_.front();
     if (info->in_flight || info->retransmittable_frames != NULL) {
       break;
@@ skipping 54 matching lines @@
   for (SequenceNumberList::const_iterator it = all_transmissions->begin();
        it != all_transmissions->end(); ++it) {
     TransmissionInfo* transmission_info =
         &unacked_packets_[*it - least_unacked_];
     MaybeRemoveRetransmittableFrames(transmission_info);
     transmission_info->all_transmissions = NULL;
   }
   delete all_transmissions;
 }
 
+void QuicUnackedPacketMap::RemoveAckability(TransmissionInfo* info) {
+  DCHECK(info->retransmittable_frames == NULL);
+  info->is_unackable = true;
+  SequenceNumberList* all_transmissions = info->all_transmissions;
+  if (all_transmissions == NULL) {
+    return;
+  }
+  for (SequenceNumberList::const_iterator it = all_transmissions->begin();
+       it != all_transmissions->end(); ++it) {
+    TransmissionInfo* transmission_info =
+        &unacked_packets_[*it - least_unacked_];
+    transmission_info->all_transmissions = NULL;
+    transmission_info->is_unackable = true;
+  }
+  delete all_transmissions;
+}
+
 void QuicUnackedPacketMap::MaybeRemoveRetransmittableFrames(
     TransmissionInfo* transmission_info) {
   if (transmission_info->retransmittable_frames != NULL) {
     if (transmission_info->retransmittable_frames->HasCryptoHandshake()
             == IS_HANDSHAKE) {
       --pending_crypto_packet_count_;
     }
     delete transmission_info->retransmittable_frames;
     transmission_info->retransmittable_frames = NULL;
   }
 }
 
 void QuicUnackedPacketMap::IncreaseLargestObserved(
     QuicPacketSequenceNumber largest_observed) {
   DCHECK_LE(largest_observed_, largest_observed);
   largest_observed_ = largest_observed;
 }
 
 bool QuicUnackedPacketMap::IsPacketUseless(
     QuicPacketSequenceNumber sequence_number,
     const TransmissionInfo& info) const {
-  return sequence_number <= largest_observed_ &&
+  return (info.is_unackable || sequence_number <= largest_observed_) &&
       !info.in_flight &&
       info.retransmittable_frames == NULL &&
       info.all_transmissions == NULL;
 }
 
 bool QuicUnackedPacketMap::IsPacketRemovable(
     QuicPacketSequenceNumber sequence_number,
     const TransmissionInfo& info) const {
-  return (sequence_number <= largest_observed_ ||
+  return (info.is_unackable ||
+          sequence_number <= largest_observed_ ||
           unacked_packets_.size() > kMaxTcpCongestionWindow) &&
       !info.in_flight &&
       info.retransmittable_frames == NULL &&
       info.all_transmissions == NULL;
 }
 
 bool QuicUnackedPacketMap::IsUnacked(
     QuicPacketSequenceNumber sequence_number) const {
   if (sequence_number < least_unacked_ ||
       sequence_number >= least_unacked_ + unacked_packets_.size()) {
@@ skipping 125 matching lines @@
   TransmissionInfo* info = &unacked_packets_[sequence_number - least_unacked_];
   DCHECK(!info->in_flight);
   DCHECK_NE(0u, info->bytes_sent);
   DCHECK(info->sent_time.IsInitialized());
 
   bytes_in_flight_ += info->bytes_sent;
   info->in_flight = true;
 }
 
 }  // namespace net