1 files changed, 108 insertions, 0 deletions
diff --git a/libtransport/src/protocols/rtc/rtc_ldr.h b/libtransport/src/protocols/rtc/rtc_ldr.h
new file mode 100644
index 000000000..c0912303b
--- /dev/null
+++ b/libtransport/src/protocols/rtc/rtc_ldr.h
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2017-2021 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+#include <hicn/transport/config.h>
+#include <hicn/transport/core/content_object.h>
+#include <hicn/transport/core/name.h>
+#include <protocols/rtc/rtc_consts.h>
+#include <protocols/rtc/rtc_state.h>
+
+#include <asio.hpp>
+#include <asio/steady_timer.hpp>
+#include <functional>
+#include <map>
+
+namespace transport {
+
+namespace protocol {
+
+namespace rtc {
+
+class RTCLossDetectionAndRecovery
+    : public std::enable_shared_from_this<RTCLossDetectionAndRecovery> {
+  struct rtx_state_ {
+    uint64_t first_send_;
+    uint64_t next_send_;
+    uint32_t rtx_count_;
+  };
+
+  using rtxState = struct rtx_state_;
+  using SendRtxCallback = std::function<void(uint32_t)>;
+
+ public:
+  RTCLossDetectionAndRecovery(SendRtxCallback &&callback,
+                              asio::io_service &io_service);
+
+  ~RTCLossDetectionAndRecovery();
+
+  void setState(std::shared_ptr<RTCState> state) { state_ = state; }
+  void turnOnRTX();
+  void turnOffRTX();
+
+  void onTimeout(uint32_t seq);
+  void onDataPacketReceived(const core::ContentObject &content_object);
+  void onNackPacketReceived(const core::ContentObject &nack);
+  void onProbePacketReceived(const core::ContentObject &probe);
+
+  void clear();
+
+  bool isRtx(uint32_t seq) {
+    if (rtx_state_.find(seq) != rtx_state_.end()) return true;
+    return false;
+  }
+
+ private:
+  void addToRetransmissions(uint32_t start, uint32_t stop);
+  uint64_t computeNextSend(uint32_t seq, bool new_rtx);
+  void retransmit();
+  void scheduleNextRtx();
+  bool deleteRtx(uint32_t seq);
+  void scheduleSentinelTimer(uint64_t expires_from_now);
+  void sentinelTimer();
+
+  uint64_t getNow() {
+    using namespace std::chrono;
+    uint64_t now =
+        duration_cast<milliseconds>(steady_clock::now().time_since_epoch())
+            .count();
+    return now;
+  }
+
+  // this map keeps track of the retransmitted interest, ordered from the oldest
+  // to the newest one. the state contains the timer of the first send of the
+  // interest (from pendingIntetests_), the timer of the next send (key of the
+  // multimap) and the number of rtx
+  std::map<uint32_t, rtxState> rtx_state_;
+  // this map stored the rtx by timer. The key is the time at which the rtx
+  // should be sent, and the val is the interest seq number
+  std::multimap<uint64_t, uint32_t> rtx_timers_;
+
+  bool rtx_on_;
+  uint64_t next_rtx_timer_;
+  uint64_t last_event_;
+  uint64_t sentinel_timer_interval_;
+  std::unique_ptr<asio::steady_timer> timer_;
+  std::unique_ptr<asio::steady_timer> sentinel_timer_;
+  std::shared_ptr<RTCState> state_;
+
+  SendRtxCallback send_rtx_callback_;
+};
+
+}  // end namespace rtc
+
+}  // end namespace protocol
+
+}  // end namespace transport