1 files changed, 93 insertions, 0 deletions
diff --git a/libtransport/src/protocols/rtc/probe_handler.h b/libtransport/src/protocols/rtc/probe_handler.h
new file mode 100644
index 000000000..d989194d4
--- /dev/null
+++ b/libtransport/src/protocols/rtc/probe_handler.h
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 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/asio_wrapper.h>
+
+#include <functional>
+#include <random>
+#include <unordered_map>
+
+namespace transport {
+
+namespace protocol {
+
+namespace rtc {
+
+enum class ProbeType {
+  NOT_PROBE,
+  INIT,
+  RTT,
+};
+
+class ProbeHandler : public std::enable_shared_from_this<ProbeHandler> {
+ public:
+  using SendProbeCallback = std::function<void(uint32_t)>;
+
+ public:
+  ProbeHandler(SendProbeCallback &&send_callback, asio::io_service &io_service);
+
+  ~ProbeHandler();
+
+  // If the function returns 0 the probe is not valid.
+  uint64_t getRtt(uint32_t seq, bool is_valid);
+
+  // this function may return a residual loss rate higher than the real one if
+  // we don't wait enough time for the probes to come back
+  double getProbeLossRate();
+
+  // Set the probe suffix range [min, max]
+  void setSuffixRange(uint32_t min, uint32_t max);
+
+  // Reset the probes parameters and stops the current probing.
+  // probe_interval = 0 means that no event will be scheduled.
+  // max_probe = 0 means no limit to the number of probe to send.
+  void setProbes(uint32_t probe_interval, uint32_t max_probes);
+
+  void stopProbes();
+
+  void sendProbes();
+
+  static ProbeType getProbeType(uint32_t seq);
+
+ private:
+  void generateProbe();
+
+  uint32_t probe_interval_;  // us
+  uint32_t max_probes_;      // packets
+  uint32_t sent_probes_;     // packets
+  uint32_t recv_probes_;     // packets
+
+  bool valid_batch_;  // if at least one probe in a batch is considered not
+                      // valid (e.g. prod rate == ~0) the full batch is invalid.
+                      // the bool is set to true when sendProbe is called
+
+  std::unique_ptr<asio::steady_timer> probe_timer_;
+
+  // Map from packet suffixes to timestamp
+  std::unordered_map<uint32_t, uint64_t> pending_probes_;
+
+  // Random generator
+  std::default_random_engine rand_eng_;
+  std::uniform_int_distribution<uint32_t> distr_;
+
+  SendProbeCallback send_probe_callback_;
+};
+
+}  // namespace rtc
+
+}  // namespace protocol
+
+}  // namespace transport