[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>

14 files changed, 446 insertions, 102 deletions

diff --git a/libtransport/includes/hicn/transport/utils/CMakeLists.txt b/libtransport/includes/hicn/transport/utils/CMakeLists.txt
index 11a9b0f25..7094601f4 100644
--- a/libtransport/includes/hicn/transport/utils/CMakeLists.txt
+++ b/libtransport/includes/hicn/transport/utils/CMakeLists.txt
@@ -31,6 +31,11 @@ list(APPEND HEADER_FILES
   ${CMAKE_CURRENT_SOURCE_DIR}/fixed_block_allocator.h
   ${CMAKE_CURRENT_SOURCE_DIR}/event_thread.h
   ${CMAKE_CURRENT_SOURCE_DIR}/string_utils.h
+  ${CMAKE_CURRENT_SOURCE_DIR}/file.h
+  ${CMAKE_CURRENT_SOURCE_DIR}/shared_ptr_utils.h
+  ${CMAKE_CURRENT_SOURCE_DIR}/move_wrapper.h
+  ${CMAKE_CURRENT_SOURCE_DIR}/noncopyable.h
+  ${CMAKE_CURRENT_SOURCE_DIR}/singleton.h
 )
 
 if(NOT WIN32)
diff --git a/libtransport/includes/hicn/transport/utils/conversions.h b/libtransport/includes/hicn/transport/utils/conversions.h
index 24b529206..52d3e3168 100644
--- a/libtransport/includes/hicn/transport/utils/conversions.h
+++ b/libtransport/includes/hicn/transport/utils/conversions.h
@@ -16,8 +16,8 @@
 #pragma once
 
 #include <hicn/transport/portability/portability.h>
-
 #include <stdio.h>
+
 #include <cstdint>
 #include <string>
 
diff --git a/libtransport/includes/hicn/transport/utils/enum_iterator.h b/libtransport/includes/hicn/transport/utils/enum_iterator.h
new file mode 100644
index 000000000..5e108b088
--- /dev/null
+++ b/libtransport/includes/hicn/transport/utils/enum_iterator.h
@@ -0,0 +1,43 @@
+/*
+ * 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.
+ */
+
+#include <type_traits>
+
+template <typename C, C begin_val, C end_val>
+class Iterator {
+  typedef typename std::underlying_type<C>::type val_t;
+  int val;
+
+ public:
+  Iterator(const C& f) : val(static_cast<val_t>(f)) {}
+
+  Iterator() : val(static_cast<val_t>(begin_val)) {}
+
+  Iterator operator++() {
+    ++val;
+    return *this;
+  }
+
+  C operator*() { return static_cast<C>(val); }
+
+  Iterator begin() { return *this; }  // default ctor is good
+
+  Iterator end() {
+    static const Iterator endIter = ++Iterator(end_val);  // cache it
+    return endIter;
+  }
+
+  bool operator!=(const Iterator& i) { return val != i.val; }
+};
\ No newline at end of file
diff --git a/libtransport/includes/hicn/transport/utils/event_thread.h b/libtransport/includes/hicn/transport/utils/event_thread.h
index 702c98f8d..bb6ab90ef 100644
--- a/libtransport/includes/hicn/transport/utils/event_thread.h
+++ b/libtransport/includes/hicn/transport/utils/event_thread.h
@@ -17,7 +17,11 @@
 
 #include <hicn/transport/config.h>
 #include <hicn/transport/errors/runtime_exception.h>
+#include <hicn/transport/utils/log.h>
 
+#ifndef ASIO_STANDALONE
+#define ASIO_STANDALONE
+#endif
 #include <asio.hpp>
 #include <memory>
 #include <thread>
@@ -25,36 +29,58 @@
 namespace utils {
 
 class EventThread {
- private:
-  // No copies
-  EventThread(const EventThread&) = delete;  // non construction-copyable
-  EventThread& operator=(const EventThread&) = delete;  // non copyable
-
  public:
-  explicit EventThread(asio::io_service& io_service)
+  EventThread(asio::io_service& io_service, bool detached = false)
       : internal_io_service_(nullptr),
-        io_service_(io_service),
+        io_service_(std::ref(io_service)),
         work_(std::make_unique<asio::io_service::work>(io_service_)),
-        thread_(nullptr) {
+        thread_(nullptr),
+        detached_(detached) {
     run();
   }
 
-  explicit EventThread()
+  EventThread(bool detached = false)
       : internal_io_service_(std::make_unique<asio::io_service>()),
-        io_service_(*internal_io_service_),
+        io_service_(std::ref(*internal_io_service_)),
         work_(std::make_unique<asio::io_service::work>(io_service_)),
-        thread_(nullptr) {
+        thread_(nullptr),
+        detached_(detached) {
     run();
   }
 
+  EventThread(const EventThread&) = delete;
+  EventThread& operator=(const EventThread&) = delete;
+
+  EventThread(EventThread&& other)
+      : internal_io_service_(std::move(other.internal_io_service_)),
+        io_service_(std::move(other.io_service_)),
+        work_(std::move(other.work_)),
+        thread_(std::move(other.thread_)),
+        detached_(std::move(other.detached_)) {}
+
+  EventThread& operator=(EventThread&& other) {
+    internal_io_service_ = std::move(other.internal_io_service_);
+    io_service_ = std::move(other.io_service_);
+    work_ = std::move(other.work_);
+    thread_ = std::move(other.thread_);
+    detached_ = other.detached_;
+
+    return *this;
+  }
+
   ~EventThread() { stop(); }
 
   void run() {
     if (stopped()) {
-      io_service_.reset();
+      io_service_.get().stopped();
     }
 
-    thread_ = std::make_unique<std::thread>([this]() { io_service_.run(); });
+    thread_ =
+        std::make_unique<std::thread>([this]() { io_service_.get().run(); });
+
+    if (detached_) {
+      thread_->detach();
+    }
   }
 
   std::thread::id getThreadId() const {
@@ -67,14 +93,12 @@ class EventThread {
 
   template <typename Func>
   void add(Func&& f) {
-    // If the function f
-    // TODO USe post in mac os, asio->post in xenial
-    io_service_.post(std::forward<Func&&>(f));
+    io_service_.get().post(std::forward<Func&&>(f));
   }
 
   template <typename Func>
   void tryRunHandlerNow(Func&& f) {
-    io_service_.dispatch(std::forward<Func&&>(f));
+    io_service_.get().dispatch(std::forward<Func&&>(f));
   }
 
   void stop() {
@@ -87,15 +111,16 @@ class EventThread {
     thread_.reset();
   }
 
-  bool stopped() { return io_service_.stopped(); }
+  bool stopped() { return io_service_.get().stopped(); }
 
   asio::io_service& getIoService() { return io_service_; }
 
  private:
   std::unique_ptr<asio::io_service> internal_io_service_;
-  asio::io_service& io_service_;
+  std::reference_wrapper<asio::io_service> io_service_;
   std::unique_ptr<asio::io_service::work> work_;
   std::unique_ptr<std::thread> thread_;
+  bool detached_;
 };
 
 }  // namespace utils
\ No newline at end of file
diff --git a/libtransport/includes/hicn/transport/utils/file.h b/libtransport/includes/hicn/transport/utils/file.h
new file mode 100644
index 000000000..4c73f33e8
--- /dev/null
+++ b/libtransport/includes/hicn/transport/utils/file.h
@@ -0,0 +1,28 @@
+/*
+ * 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.
+ */
+
+#include <sys/stat.h>
+
+namespace utils {
+
+class File {
+ public:
+  static inline bool exists(const std::string& name) {
+    struct stat buffer;
+    return (stat(name.c_str(), &buffer) == 0);
+  }
+};
+
+}  // namespace utils
diff --git a/libtransport/includes/hicn/transport/utils/fixed_block_allocator.h b/libtransport/includes/hicn/transport/utils/fixed_block_allocator.h
index 1ade1516e..b1df36493 100644
--- a/libtransport/includes/hicn/transport/utils/fixed_block_allocator.h
+++ b/libtransport/includes/hicn/transport/utils/fixed_block_allocator.h
@@ -5,104 +5,99 @@
 #pragma once
 
 #include <hicn/transport/portability/c_portability.h>
+#include <hicn/transport/utils/singleton.h>
 #include <hicn/transport/utils/spinlock.h>
-
 #include <stdint.h>
+
+#include <cassert>
 #include <cstdlib>
 #include <memory>
-#include <cassert>
 
 namespace utils {
-template <std::size_t DEFAULT_SIZE = 512, std::size_t OBJECTS = 4096>
-class FixedBlockAllocator {
-  FixedBlockAllocator(std::size_t size = DEFAULT_SIZE,
-                      std::size_t objects = OBJECTS)
-      : block_size_(size < sizeof(void*) ? sizeof(long*) : size),
-        object_size_(size),
-        max_objects_(objects),
-        p_head_(NULL),
-        pool_index_(0),
-        block_count_(0),
-        blocks_in_use_(0),
-        allocations_(0),
-        deallocations_(0) {
-    p_pool_ = (uint8_t*)new uint8_t[block_size_ * max_objects_];
-  }
+template <std::size_t SIZE = 512, std::size_t OBJECTS = 4096>
+class FixedBlockAllocator
+    : public utils::Singleton<FixedBlockAllocator<SIZE, OBJECTS>> {
+  friend class utils::Singleton<FixedBlockAllocator<SIZE, OBJECTS>>;
 
  public:
-  static FixedBlockAllocator* getInstance() {
-    if (!instance_) {
-      instance_ = std::unique_ptr<FixedBlockAllocator>(
-          new FixedBlockAllocator(DEFAULT_SIZE, OBJECTS));
+  ~FixedBlockAllocator() {
+    for (auto& p : p_pools_) {
+      delete[] p;
     }
-
-    return instance_.get();
   }
 
-  ~FixedBlockAllocator() { delete[] p_pool_; }
-
-  TRANSPORT_ALWAYS_INLINE void* allocateBlock(size_t size = DEFAULT_SIZE) {
-    assert(size <= DEFAULT_SIZE);
+  void* allocateBlock(size_t size = SIZE) {
+    assert(size <= SIZE);
     uint32_t index;
 
+    SpinLock::Acquire locked(lock_);
     void* p_block = pop();
     if (!p_block) {
-      if (pool_index_ < max_objects_) {
-        {
-          SpinLock::Acquire locked(lock_);
-          index = pool_index_++;
-        }
-        p_block = (void*)(p_pool_ + (index * block_size_));
-      } else {
-        // TODO Consider increasing pool here instead of throwing an exception
-        throw std::runtime_error("No more memory available from packet pool!");
+      if (TRANSPORT_EXPECT_FALSE(current_pool_index_ >= max_objects_)) {
+        // Allocate new memory block
+        TRANSPORT_LOGV("Allocating new block of %zu size", SIZE * OBJECTS);
+        p_pools_.emplace_front(
+            new typename std::aligned_storage<SIZE>::type[max_objects_]);
+        // reset current_pool_index_
+        current_pool_index_ = 0;
       }
-    }
 
-    blocks_in_use_++;
-    allocations_++;
+      auto& latest = p_pools_.front();
+      index = current_pool_index_++;
+      blocks_in_use_++;
+      allocations_++;
+      p_block = (void*)&latest[index];
+    }
 
     return p_block;
   }
 
-  TRANSPORT_ALWAYS_INLINE void deallocateBlock(void* pBlock) {
+  void deallocateBlock(void* pBlock) {
+    SpinLock::Acquire locked(lock_);
     push(pBlock);
-    {
-      SpinLock::Acquire locked(lock_);
-      blocks_in_use_--;
-      deallocations_++;
-    }
+    blocks_in_use_--;
+    deallocations_++;
   }
 
-  TRANSPORT_ALWAYS_INLINE std::size_t blockSize() { return block_size_; }
+ public:
+  std::size_t blockSize() { return block_size_; }
 
-  TRANSPORT_ALWAYS_INLINE uint32_t blockCount() { return block_count_; }
+  uint32_t blockCount() { return block_count_; }
 
-  TRANSPORT_ALWAYS_INLINE uint32_t blocksInUse() { return blocks_in_use_; }
+  uint32_t blocksInUse() { return blocks_in_use_; }
 
-  TRANSPORT_ALWAYS_INLINE uint32_t allocations() { return allocations_; }
+  uint32_t allocations() { return allocations_; }
 
-  TRANSPORT_ALWAYS_INLINE uint32_t deallocations() { return deallocations_; }
+  uint32_t deallocations() { return deallocations_; }
 
  private:
-  TRANSPORT_ALWAYS_INLINE void push(void* p_memory) {
+  FixedBlockAllocator()
+      : block_size_(SIZE),
+        object_size_(SIZE),
+        max_objects_(OBJECTS),
+        p_head_(NULL),
+        current_pool_index_(0),
+        block_count_(0),
+        blocks_in_use_(0),
+        allocations_(0),
+        deallocations_(0) {
+    static_assert(SIZE >= sizeof(long*), "SIZE must be at least 8 bytes");
+    p_pools_.emplace_front(
+        new typename std::aligned_storage<SIZE>::type[max_objects_]);
+  }
+
+  void push(void* p_memory) {
     Block* p_block = (Block*)p_memory;
-    {
-      SpinLock::Acquire locked(lock_);
-      p_block->p_next = p_head_;
-      p_head_ = p_block;
-    }
+    p_block->p_next = p_head_;
+    p_head_ = p_block;
   }
 
-  TRANSPORT_ALWAYS_INLINE void* pop() {
+  void* pop() {
     Block* p_block = nullptr;
 
-    {
-      SpinLock::Acquire locked(lock_);
-      if (p_head_) {
-        p_block = p_head_;
-        p_head_ = p_head_->p_next;
-      }
+    if (p_head_) {
+      p_block = p_head_;
+      p_head_ = p_head_->p_next;
     }
 
     return (void*)p_block;
@@ -119,8 +114,8 @@ class FixedBlockAllocator {
   const std::size_t max_objects_;
 
   Block* p_head_;
-  uint8_t* p_pool_;
-  uint32_t pool_index_;
+  uint32_t current_pool_index_;
+  std::list<typename std::aligned_storage<SIZE>::type*> p_pools_;
   uint32_t block_count_;
   uint32_t blocks_in_use_;
   uint32_t allocations_;
@@ -133,4 +128,88 @@ template <std::size_t A, std::size_t B>
 std::unique_ptr<FixedBlockAllocator<A, B>>
     FixedBlockAllocator<A, B>::instance_ = nullptr;
 
+/**
+ * STL Allocator trait to be used with allocate_shared.
+ */
+template <typename T, typename Pool>
+class STLAllocator {
+  /**
+   * If STLAllocator is rebound to another type (!= T) using copy constructor,
+   * we may need to access private members of the source allocator to copy
+   * memory and pool.
+   */
+  template <typename U, typename P>
+  friend class STLAllocator;
+
+ public:
+  using size_type = std::size_t;
+  using difference_type = ptrdiff_t;
+  using pointer = T*;
+  using const_pointer = const T*;
+  using reference = T&;
+  using const_reference = const T&;
+  using value_type = T;
+
+  STLAllocator(pointer memory, Pool* memory_pool)
+      : memory_(memory), pool_(memory_pool) {
+    TRANSPORT_LOGV("Creating allocator. This: %p, memory: %p, memory_pool: %p",
+                   this, memory, memory_pool);
+  }
+
+  ~STLAllocator() {}
+
+  template <typename U>
+  STLAllocator(const STLAllocator<U, Pool>& other) {
+    memory_ = other.memory_;
+    pool_ = other.pool_;
+  }
+
+  template <typename U>
+  struct rebind {
+    typedef STLAllocator<U, Pool> other;
+  };
+
+  pointer address(reference x) const { return &x; }
+  const_pointer address(const_reference x) const { return &x; }
+
+  pointer allocate(size_type n, pointer hint = 0) {
+    TRANSPORT_LOGV(
+        "Allocating memory (%zu). This: %p, memory: %p, memory_pool: %p", n,
+        this, memory_, pool_);
+    return static_cast<pointer>(memory_);
+  }
+
+  void deallocate(pointer p, size_type n) {
+    TRANSPORT_LOGV("Deallocating memory. This: %p, memory: %p, memory_pool: %p",
+                   this, memory_, pool_);
+    pool_->deallocateBlock(memory_);
+  }
+
+  template <typename... Args>
+  void construct(pointer p, Args&&... args) {
+    new (static_cast<pointer>(p)) T(std::forward<Args>(args)...);
+  }
+
+  void destroy(pointer p) {
+    TRANSPORT_LOGV("Destroying object. This: %p, memory: %p, memory_pool: %p",
+                   this, memory_, pool_);
+    p->~T();
+  }
+
+ private:
+  void* memory_;
+  Pool* pool_;
+};
+
+template <typename T, typename U, typename V>
+inline bool operator==(const STLAllocator<T, V>&, const STLAllocator<U, V>&) {
+  return true;
+}
+
+template <typename T, typename U, typename V>
+inline bool operator!=(const STLAllocator<T, V>& a,
+                       const STLAllocator<U, V>& b) {
+  return !(a == b);
+}
+
 }  // namespace utils
\ No newline at end of file
diff --git a/libtransport/includes/hicn/transport/utils/linux.h b/libtransport/includes/hicn/transport/utils/linux.h
index 5820528e1..105196fd2 100644
--- a/libtransport/includes/hicn/transport/utils/linux.h
+++ b/libtransport/includes/hicn/transport/utils/linux.h
@@ -17,14 +17,14 @@
 
 #ifdef __linux__
 
+#include <arpa/inet.h>
 #include <hicn/transport/portability/portability.h>
 #include <hicn/transport/utils/log.h>
-
-#include <arpa/inet.h>
 #include <ifaddrs.h>
 #include <netdb.h>
 #include <stdio.h>
 #include <sys/socket.h>
+
 #include <string>
 
 #define LINK_LOCAL_PREFIX 0xfe80
diff --git a/libtransport/includes/hicn/transport/utils/membuf.h b/libtransport/includes/hicn/transport/utils/membuf.h
index 9fc37dd25..0db87e9dd 100644
--- a/libtransport/includes/hicn/transport/utils/membuf.h
+++ b/libtransport/includes/hicn/transport/utils/membuf.h
@@ -23,6 +23,7 @@
 
 #include <hicn/transport/portability/portability.h>
 #include <hicn/transport/utils/branch_prediction.h>
+#include <stdlib.h>
 
 #include <atomic>
 #include <cassert>
@@ -35,8 +36,6 @@
 #include <type_traits>
 #include <vector>
 
-#include <stdlib.h>
-
 #ifndef _WIN32
 TRANSPORT_GNU_DISABLE_WARNING("-Wshadow")
 #endif
@@ -50,6 +49,8 @@ class MemBuf {
   enum TakeOwnershipOp { TAKE_OWNERSHIP };
   enum CopyBufferOp { COPY_BUFFER };
 
+  using Ptr = std::shared_ptr<MemBuf>;
+
   typedef void (*FreeFunction)(void* buf, void* userData);
 
   static std::unique_ptr<MemBuf> create(std::size_t capacity);
@@ -106,13 +107,14 @@ class MemBuf {
          FreeFunction freeFn = nullptr, void* userData = nullptr,
          bool freeOnError = true);
 
-  static std::unique_ptr<MemBuf> wrapBuffer(const void* buf,
+  static std::unique_ptr<MemBuf> wrapBuffer(const void* buf, std::size_t length,
                                             std::size_t capacity);
 
-  static MemBuf wrapBufferAsValue(const void* buf,
+  static MemBuf wrapBufferAsValue(const void* buf, std::size_t length,
                                   std::size_t capacity) noexcept;
 
-  MemBuf(WrapBufferOp op, const void* buf, std::size_t capacity) noexcept;
+  MemBuf(WrapBufferOp op, const void* buf, std::size_t length,
+         std::size_t capacity) noexcept;
 
   /**
    * Convenience function to create a new MemBuf object that copies data from a
@@ -147,6 +149,8 @@ class MemBuf {
 
   std::size_t length() const { return length_; }
 
+  void setLength(std::size_t length) { length_ = length; }
+
   std::size_t headroom() const { return std::size_t(data_ - buffer()); }
 
   std::size_t tailroom() const { return std::size_t(bufferEnd() - tail()); }
@@ -689,6 +693,18 @@ class MemBuf {
                                                   void* userData = nullptr,
                                                   bool freeOnError = true);
 
+  /**
+   * Ensure the current MemBuf can hold at least capacity bytes and its
+   * memory is contiguous
+   */
+  bool ensureCapacity(std::size_t capacity);
+
+  /**
+   * Ensure packet buffer can hold at least 1500 bytes in contiguous memory and
+   * fill unused memory with placeholder
+   */
+  bool ensureCapacityAndFillUnused(std::size_t capacity, uint8_t placeholder);
+
   /*
    * Overridden operator new and delete.
    * These perform specialized memory management to help support
@@ -700,6 +716,12 @@ class MemBuf {
   void operator delete(void* ptr);
   void operator delete(void* ptr, void* placement);
 
+  /**
+   * Override operator == and !=
+   */
+  bool operator ==(const MemBuf &other);
+  bool operator !=(const MemBuf &other);
+
   // /**
   //  * Iteration support: a chain of MemBufs may be iterated through using
   //  * STL-style iterators over const ByteRanges.  Iterators are only
diff --git a/libtransport/includes/hicn/transport/utils/move_wrapper.h b/libtransport/includes/hicn/transport/utils/move_wrapper.h
new file mode 100644
index 000000000..3aba345d6
--- /dev/null
+++ b/libtransport/includes/hicn/transport/utils/move_wrapper.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2017-2019 Cisco and/or its affiliates.
+ * Copyright 2017 Facebook, Inc.
+ *
+ * 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 <type_traits>
+
+namespace utils {
+
+template <typename F>
+struct MoveWrapper : F {
+  MoveWrapper(F&& f) : F(std::move(f)) {}
+
+  MoveWrapper(MoveWrapper&&) = default;
+  MoveWrapper& operator=(MoveWrapper&&) = default;
+
+  MoveWrapper(const MoveWrapper&);
+  MoveWrapper& operator=(const MoveWrapper&);
+};
+
+template <typename T>
+auto moveHandler(T&& t) -> MoveWrapper<typename std::decay<T>::type> {
+  return std::move(t);
+}
+}  // namespace utils
\ No newline at end of file
diff --git a/libtransport/includes/hicn/transport/utils/noncopyable.h b/libtransport/includes/hicn/transport/utils/noncopyable.h
new file mode 100644
index 000000000..83923e647
--- /dev/null
+++ b/libtransport/includes/hicn/transport/utils/noncopyable.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2017-2019 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
+
+namespace utils {
+
+class NonCopyable {
+ protected:
+  NonCopyable() = default;
+  ~NonCopyable() = default;
+
+  NonCopyable(const NonCopyable&) = delete;
+  NonCopyable& operator=(const NonCopyable&) = delete;
+};
+
+}  // namespace utils
diff --git a/libtransport/includes/hicn/transport/utils/object_pool.h b/libtransport/includes/hicn/transport/utils/object_pool.h
index f78bd2aa2..a5e8b2eef 100644
--- a/libtransport/includes/hicn/transport/utils/object_pool.h
+++ b/libtransport/includes/hicn/transport/utils/object_pool.h
@@ -17,6 +17,7 @@
 
 // TODO
 #include <hicn/transport/utils/branch_prediction.h>
+#include <hicn/transport/utils/log.h>
 #include <hicn/transport/utils/spinlock.h>
 
 #include <deque>
@@ -33,6 +34,7 @@ class ObjectPool {
 
     void operator()(T *t) {
       if (pool_) {
+        TRANSPORT_LOGV("Back in pool");
         pool_->add(t);
       } else {
         delete t;
@@ -44,10 +46,13 @@ class ObjectPool {
   };
 
  public:
-  using Ptr = std::unique_ptr<T, ObjectDeleter>;
+  using Ptr = std::shared_ptr<T>;
 
   ObjectPool() : destructor_(false) {}
 
+  // No copies
+  ObjectPool(const ObjectPool &other) = delete;
+
   ~ObjectPool() {
     destructor_ = true;
     for (auto &ptr : object_pool_) {
@@ -55,12 +60,17 @@ class ObjectPool {
     }
   }
 
+  bool empty() {
+    utils::SpinLock::Acquire locked(object_pool_lock_);
+    return object_pool_.empty();
+  }
+
   std::pair<bool, Ptr> get() {
+    utils::SpinLock::Acquire locked(object_pool_lock_);
     if (object_pool_.empty()) {
-      return std::make_pair<bool, Ptr>(false, makePtr(nullptr));
+      return std::make_pair<bool, Ptr>(false, nullptr);
     }
 
-    utils::SpinLock::Acquire locked(object_pool_lock_);
     auto ret = std::move(object_pool_.front());
     object_pool_.pop_front();
     return std::make_pair<bool, Ptr>(true, std::move(ret));
@@ -70,7 +80,7 @@ class ObjectPool {
     utils::SpinLock::Acquire locked(object_pool_lock_);
 
     if (TRANSPORT_EXPECT_TRUE(!destructor_)) {
-      object_pool_.emplace_back(makePtr(object));
+      object_pool_.emplace_front(makePtr(object));
     } else {
       delete object;
     }
@@ -79,12 +89,9 @@ class ObjectPool {
   Ptr makePtr(T *object) { return Ptr(object, ObjectDeleter(this)); }
 
  private:
-  // No copies
-  ObjectPool(const ObjectPool &other) = delete;
-
   utils::SpinLock object_pool_lock_;
   std::deque<Ptr> object_pool_;
-  bool destructor_;
+  std::atomic<bool> destructor_;
 };
 
-}  // namespace utils
\ No newline at end of file
+}  // namespace utils
diff --git a/libtransport/includes/hicn/transport/utils/shared_ptr_utils.h b/libtransport/includes/hicn/transport/utils/shared_ptr_utils.h
new file mode 100644
index 000000000..3387997b5
--- /dev/null
+++ b/libtransport/includes/hicn/transport/utils/shared_ptr_utils.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2021 Cisco and/or its affiliates.
+ */
+
+#pragma once
+
+#include <memory>
+
+namespace utils {
+
+template <typename Base>
+inline std::shared_ptr<Base> shared_from_base(
+    std::enable_shared_from_this<Base>* base) {
+  return base->shared_from_this();
+}
+
+template <typename Base>
+inline std::shared_ptr<const Base> shared_from_base(
+    std::enable_shared_from_this<Base> const* base) {
+  return base->shared_from_this();
+}
+
+template <typename That>
+inline std::shared_ptr<That> shared_from(That* that) {
+  return std::static_pointer_cast<That>(shared_from_base(that));
+}
+
+}  // namespace utils
\ No newline at end of file
diff --git a/libtransport/includes/hicn/transport/utils/singleton.h b/libtransport/includes/hicn/transport/utils/singleton.h
new file mode 100644
index 000000000..7fd8b912f
--- /dev/null
+++ b/libtransport/includes/hicn/transport/utils/singleton.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2017-2019 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/utils/noncopyable.h>
+
+namespace utils {
+
+template <typename T>
+class Singleton {
+ public:
+  static T& getInstance() {
+    static T instance;
+    return instance;
+  }
+
+ protected:
+  Singleton() {}
+  ~Singleton() {}
+
+ public:
+  Singleton(Singleton const&) = delete;
+  Singleton& operator=(Singleton const&) = delete;
+};
+
+}  // namespace utils
\ No newline at end of file
diff --git a/libtransport/includes/hicn/transport/utils/string_utils.h b/libtransport/includes/hicn/transport/utils/string_utils.h
index bfda816f1..313c28cc6 100644
--- a/libtransport/includes/hicn/transport/utils/string_utils.h
+++ b/libtransport/includes/hicn/transport/utils/string_utils.h
@@ -72,4 +72,4 @@ static inline std::string trim_copy(std::string s) {
   return s;
 }
 
-}
\ No newline at end of file
+}  // namespace utils
\ No newline at end of file