[HICN-690] Transport Library Major Refactory

The current patch provides a major refactory of the transportlibrary.
A summary of the different components that underwent major modifications is
reported below.

- Transport protocol updates
The hierarchy of classes has been optimized to have common transport services
across different transport protocols. This can allow to customize a transport
protocol with new features.

- A new real-time communication protocol
The RTC protocol has been optimized in terms of algorithms to reduce
consumer-producer synchronization latency.

- A novel socket API
The API has been reworked to be easier to consumer but also to have a more
efficient integration in L4 proxies.

- Several performance improvements
A large number of performance improvements have been included in
particular to make the entire stack zero-copy and optimize cache miss.

- New memory buffer framework
Memory management has been reworked entirely to provide a more efficient infra
with a richer API. Buffers are now allocated in blocks and a single buffer
holds the memory for (1) the shared_ptr control block, (2) the metadata of the
packet (e.g. name, pointer to other buffers if buffer is chained and relevant
offsets), and (3) the packet itself, as it is sent/received over the network.

- A new slab allocator
Dynamic memory allocation is now managed by a novel slab allocator that is
optimised for packet processing and connection management. Memory is organized
in pools of blocks all of the same size which are used during the processing of
outgoing/incoming packets. When a memory block Is allocated is always taken
from a global pool and when it is deallocated is returned to the pool, thus
avoiding the cost of any heap allocation in the data path.

- New transport connectors
Consumer and producer end-points can communication either using an hicn packet
forwarder or with direct connector based on shared memories or sockets.
The usage of transport connectors typically for unit and funcitonal
testing but may have additional usage.

- Support for FEC/ECC for transport services
FEC/ECC via reed solomon is supported by default and made available to
transport services as a modular component. Reed solomon block codes is a
default FEC model that can be replaced in a modular way by many other
codes including RLNC not avaiable in this distribution.
The current FEC framework support variable size padding and efficiently
makes use of the infra memory buffers to avoid additiona copies.

- Secure transport framework for signature computation and verification
Crypto support is nativelty used in hICN for integrity and authenticity.
Novel support that includes RTC has been implemented and made modular
and reusable acrosso different transport protocols.

- TLS - Transport layer security over hicn
Point to point confidentiality is provided by integrating TLS on top of
hICN reliable and non-reliable transport. The integration is common and
makes a different use of the TLS record.

- MLS - Messaging layer security over hicn
MLS integration on top of hICN is made by using the MLSPP implemetation
open sourced by Cisco. We have included instrumentation tools to deploy
performance and functional tests of groups of end-points.

- Android support
The overall code has been heavily tested in Android environments and
has received heavy lifting to better run natively in recent Android OS.

Co-authored-by: Mauro Sardara <msardara@cisco.com>
Co-authored-by: Michele Papalini <micpapal@cisco.com>
Co-authored-by: Olivier Roques <oroques+fdio@cisco.com>
Co-authored-by: Giulio Grassi <gigrassi@cisco.com>
Change-Id: If477ba2fa686e6f47bdf96307ac60938766aef69
Signed-off-by: Luca Muscariello <muscariello@ieee.org>

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