2 files changed, 105 insertions, 8 deletions

diff --git a/libtransport/src/hicn/transport/protocols/rtc.cc b/libtransport/src/hicn/transport/protocols/rtc.cc
index e6134f767..f52494aba 100644
--- a/libtransport/src/hicn/transport/protocols/rtc.cc
+++ b/libtransport/src/hicn/transport/protocols/rtc.cc
@@ -33,6 +33,7 @@ RTCTransportProtocol::RTCTransportProtocol(
   icnet_socket->getSocketOption(PORTAL, portal_);
   rtx_timer_ = std::make_unique<asio::steady_timer>(portal_->getIoService());
   probe_timer_ = std::make_unique<asio::steady_timer>(portal_->getIoService());
+  sentinel_timer_ = std::make_unique<asio::steady_timer>(portal_->getIoService());
   reset();
 }
 
@@ -90,6 +91,7 @@ void RTCTransportProtocol::reset() {
   lastReceivedTime_ = std::chrono::duration_cast<std::chrono::milliseconds>(
                           std::chrono::steady_clock::now().time_since_epoch())
                           .count();
+  lastEvent_ = lastReceivedTime_;
   highestReceived_ = 0;
   firstSequenceInRound_ = 0;
 
@@ -108,6 +110,7 @@ void RTCTransportProtocol::reset() {
   avgPacketSize_ = HICN_INIT_PACKET_SIZE;
   gotNack_ = false;
   gotFutureNack_ = 0;
+  rounds_ = 0;
   roundsWithoutNacks_ = 0;
   pathTable_.clear();
 
@@ -228,6 +231,11 @@ void RTCTransportProtocol::updateStats(uint32_t round_duration) {
       pathTable_.find(producerPathLabels_[1]) == pathTable_.end())
     return;  // this should not happen
 
+  //set sentinel timer if needed
+  if(rounds_ == 0){
+    sentinelTimer();
+  }
+
   // as a queuing delay we keep the lowest one among the two paths
   // if one path is congested the forwarder should decide to do not
   // use it so it does not make sense  to inform the application
@@ -304,6 +312,7 @@ void RTCTransportProtocol::updateStats(uint32_t round_duration) {
   receivedData_ = 0;
   packetLost_ = 0;
   lossRecovered_ = 0;
+  rounds_++;
   firstSequenceInRound_ = highestReceived_;
 }
 
@@ -434,6 +443,7 @@ void RTCTransportProtocol::sendInterest(Name *interest_name, bool rtx) {
   sentInterest_++;
 
   if (!rtx) {
+    packets_in_window_[interest_name->getSuffix()] = 0;
     inflightInterestsCount_++;
   }
 }
@@ -499,6 +509,57 @@ void RTCTransportProtocol::scheduleNextInterests() {
   }
 }
 
+void RTCTransportProtocol::sentinelTimer(){
+  uint32_t wait = 1;
+  if(pathTable_.find(producerPathLabels_[0]) != pathTable_.end()){
+    wait = round(
+            pathTable_[producerPathLabels_[0]]->getInterArrivalGap());
+  }
+  if(wait == 0)
+    wait  = 1;
+
+  sentinel_timer_->expires_from_now(std::chrono::milliseconds(wait));
+  sentinel_timer_->async_wait([this](std::error_code ec) {
+    if (ec) return;
+    uint64_t now = std::chrono::duration_cast<std::chrono::milliseconds>(
+                   std::chrono::steady_clock::now().time_since_epoch())
+                   .count();
+
+    if(pathTable_.find(producerPathLabels_[0]) != pathTable_.end() ||
+        pathTable_.find(producerPathLabels_[1]) != pathTable_.end()){
+
+      uint64_t max_waiting_time =
+              round((pathTable_[producerPathLabels_[1]]->getMinRtt() -
+                pathTable_[producerPathLabels_[0]]->getMinRtt()) +
+                pathTable_[producerPathLabels_[0]]->getInterArrivalGap()) * 2;
+
+      if((currentState_ == HICN_RTC_NORMAL_STATE) &&
+          (inflightInterestsCount_ >= currentCWin_) &&
+          ((now - lastEvent_) > max_waiting_time)){
+
+        uint64_t RTT =  pathTable_[producerPathLabels_[1]]->getMinRtt();
+
+        for(auto it = packets_in_window_.begin();
+                  it != packets_in_window_.end(); it++){
+          uint32_t pkt = it->first & modMask_;
+          if (inflightInterests_[pkt].sequence == it->first &&
+            ((now - inflightInterests_[pkt].transmissionTime) >= RTT)){
+              inflightInterests_[pkt].transmissionTime = now;
+              Name *interest_name = nullptr;
+              socket_->getSocketOption(GeneralTransportOptions::NETWORK_NAME,
+                               &interest_name);
+              interest_name->setSuffix(it->first);
+              it->second++;
+              sendInterest(interest_name, true);
+          }
+        }
+      }
+    }//esle not enough info to resend the packet, schedule the timer agian
+
+    sentinelTimer();
+  });
+}
+
 void RTCTransportProtocol::addRetransmissions(uint32_t val) {
   // add only val in the rtx list
   addRetransmissions(val, val + 1);
@@ -651,8 +712,6 @@ void RTCTransportProtocol::checkRtx() {
 }
 
 void RTCTransportProtocol::onTimeout(Interest::Ptr &&interest) {
-  // packetLost_++;
-
   uint32_t segmentNumber = interest->getName().getSuffix();
 
   if (segmentNumber >= HICN_MIN_PROBE_SEQ) {
@@ -663,14 +722,22 @@ void RTCTransportProtocol::onTimeout(Interest::Ptr &&interest) {
   uint32_t pkt = segmentNumber & modMask_;
 
   if (TRANSPORT_EXPECT_FALSE(!firstPckReceived_)) {
-    inflightInterestsCount_--;
     // we do nothing, and we keep asking the same stuff over
     // and over until we get at least a packet
+    inflightInterestsCount_--;
+    lastEvent_ = std::chrono::duration_cast<std::chrono::milliseconds>(
+                 std::chrono::steady_clock::now().time_since_epoch())
+                 .count();
+    packets_in_window_.erase(segmentNumber);
     scheduleNextInterests();
     return;
   }
 
   if (inflightInterests_[pkt].state == sent_) {
+    lastEvent_ = std::chrono::duration_cast<std::chrono::milliseconds>(
+                 std::chrono::steady_clock::now().time_since_epoch())
+                 .count();
+    packets_in_window_.erase(segmentNumber);
     inflightInterestsCount_--;
   }
 
@@ -795,15 +862,30 @@ void RTCTransportProtocol::onContentObject(
     return;
   }
 
+  //check if the packet is a rtx
+  bool is_rtx = false;
+  if(interestRetransmissions_.find(segmentNumber) !=
+        interestRetransmissions_.end()){
+    is_rtx = true;
+  }else{
+    auto it_win = packets_in_window_.find(segmentNumber);
+    if(it_win != packets_in_window_.end() &&
+       it_win->second != 0)
+    is_rtx = true;
+  }
+
   if (payload_size == HICN_NACK_HEADER_SIZE) {
     if (inflightInterests_[pkt].state == sent_) {
+      lastEvent_ = std::chrono::duration_cast<std::chrono::milliseconds>(
+                   std::chrono::steady_clock::now().time_since_epoch())
+                   .count();
+      packets_in_window_.erase(segmentNumber);
       inflightInterestsCount_--;
     }
 
     bool old_nack = false;
 
-    if (interestRetransmissions_.find(segmentNumber) ==
-        interestRetransmissions_.end()) {
+    if (!is_rtx){
       // this is not a retransmitted packet
       old_nack = onNack(*content_object, false);
       updateDelayStats(*content_object);
@@ -831,12 +913,14 @@ void RTCTransportProtocol::onContentObject(
                                  content_object->payloadSize());
 
     if (inflightInterests_[pkt].state == sent_) {
+      lastEvent_ = std::chrono::duration_cast<std::chrono::milliseconds>(
+                   std::chrono::steady_clock::now().time_since_epoch())
+                   .count();
+      packets_in_window_.erase(segmentNumber);
       inflightInterestsCount_--;  // packet sent without timeouts
     }
 
-    if (inflightInterests_[pkt].state == sent_ &&
-        interestRetransmissions_.find(segmentNumber) ==
-            interestRetransmissions_.end()) {
+    if (inflightInterests_[pkt].state == sent_ && !is_rtx){
       // delay stats are computed only for non retransmitted data
       updateDelayStats(*content_object);
     }
diff --git a/libtransport/src/hicn/transport/protocols/rtc.h b/libtransport/src/hicn/transport/protocols/rtc.h
index 7927e3969..908be017a 100644
--- a/libtransport/src/hicn/transport/protocols/rtc.h
+++ b/libtransport/src/hicn/transport/protocols/rtc.h
@@ -123,6 +123,7 @@ class RTCTransportProtocol : public TransportProtocol, public Reassembly {
   // packet functions
   void sendInterest(Name *interest_name, bool rtx);
   void scheduleNextInterests() override;
+  void sentinelTimer();
   void addRetransmissions(uint32_t val);
   void addRetransmissions(uint32_t start, uint32_t stop);
   uint64_t retransmit();
@@ -163,6 +164,17 @@ class RTCTransportProtocol : public TransportProtocol, public Reassembly {
   uint64_t lastReceivedTime_; //time at which we recevied the
                               //lastReceived_ packet
 
+  //sentinel
+  //if all packets in the window get lost we need something that
+  //wakes up our consumer socket. Interest timeouts set to 1 sec
+  //expire too late. This timers expire much sooner and if it
+  //detects that all the interest in the window may be lost
+  //it sends all of them again
+  std::unique_ptr<asio::steady_timer> sentinel_timer_;
+  uint64_t lastEvent_; //time at which we removed a pending
+                      //interest from the window
+  std::unordered_map<uint32_t, uint8_t> packets_in_window_;
+
   //rtt probes
   //the RTC transport tends to overestimate the RTT
   //du to the production time on the server side
@@ -188,6 +200,7 @@ class RTCTransportProtocol : public TransportProtocol, public Reassembly {
   double avgPacketSize_;
   bool gotNack_;
   uint32_t gotFutureNack_;
+  uint32_t rounds_;
   uint32_t roundsWithoutNacks_;
 
   //we keep track of up two paths (if only one path is in use