Inet: Split UDPEndPoint and TCPEndPoint (#11681)

#### Problem

This is a step toward #7715 _Virtualize System and Inet interfaces_.

#### Change overview

- The per-implementation subclasses (formerly `#if` sections) of
  `EndPointBase` didn't actually depend on `EndPointBase` at all,
  so they are split off into `EndPointState${IMPL}` classes,
  separately inherited by the leaf classes.

- `UDPEndPoint` and `TCPEndPoint` are split into base classes and
  per-implementation subclasses. Transitionally, the implementation
  classes remain the main files, and are instantiated using a single
  concrete name by `#if`.

#### Testing

CI; no changes to functionality.

src/inet/BUILD.gn

@@ -49,8 +49,6 @@ buildconfig_header("inet_buildconfig") {
     defines +=
         [ "INET_PLATFORM_CONFIG_INCLUDE=${chip_inet_platform_config_include}" ]
   }
-
-  defines += [ "CHIP_INET_END_POINT_IMPL_CONFIG_FILE=<inet/EndPointBasisImpl${chip_system_config_inet}.h>" ]
 }
 
 source_set("inet_config_header") {
@@ -69,7 +67,7 @@ static_library("inet") {
 
   sources = [
     "EndPointBasis.h",
-    "EndPointBasisImpl${chip_system_config_inet}.h",
+    "EndPointState${chip_system_config_inet}.h",
     "IANAConstants.h",
     "IPAddress-StringFuncts.cpp",
     "IPAddress.cpp",

src/inet/EndPointBasis.h

@@ -39,7 +39,6 @@ class DLL_EXPORT EndPointBase
 {
 public:
     EndPointBase(InetLayer & aInetLayer, void * aAppState = nullptr) : mAppState(aAppState), mInetLayer(aInetLayer) {}
-    virtual ~EndPointBase() = default;
 
     /**
      *  Returns a reference to the Inet layer object that owns this basis object.
@@ -54,9 +53,3 @@ class DLL_EXPORT EndPointBase
 
 } // namespace Inet
 } // namespace chip
-
-#ifdef CHIP_INET_END_POINT_IMPL_CONFIG_FILE
-#include CHIP_INET_END_POINT_IMPL_CONFIG_FILE
-#else // CHIP_INET_END_POINT_IMPL_CONFIG_FILE
-#include <inet/EndPointBasisImplSockets.h>
-#endif // CHIP_INET_END_POINT_IMPL_CONFIG_FILE

src/inet/EndPointBasisImplLwIP.h → src/inet/EndPointStateLwIP.h

@@ -17,7 +17,7 @@
  */
 
 /**
- *  LwIP implementation of EndPointBase.
+ *  Shared state for LwIP implementations of TCPEndPoint and UDPEndPoint.
  */
 
 #pragma once
@@ -32,12 +32,10 @@ struct tcp_pcb;
 namespace chip {
 namespace Inet {
 
-class DLL_EXPORT EndPointImplLwIP : public EndPointBase
+class DLL_EXPORT EndPointStateLwIP
 {
 protected:
-    EndPointImplLwIP(InetLayer & inetLayer, void * appState = nullptr) :
-        EndPointBase(inetLayer, appState), mLwIPEndPointType(LwIPEndPointType::Unknown)
-    {}
+    EndPointStateLwIP() : mLwIPEndPointType(LwIPEndPointType::Unknown) {}
 
     /** Encapsulated LwIP protocol control block */
     union
@@ -59,7 +57,5 @@ class DLL_EXPORT EndPointImplLwIP : public EndPointBase
     } mLwIPEndPointType;
 };
 
-using EndPointBasis = EndPointImplLwIP;
-
 } // namespace Inet
 } // namespace chip

src/inet/EndPointBasisImplNetworkFramework.h → src/inet/EndPointStateNetworkFramework.h

@@ -17,7 +17,7 @@
  */
 
 /**
- *  Network Framework implementation of EndPointBase.
+ *  Shared state for Network Framework implementations of TCPEndPoint and UDPEndPoint.
  */
 
 #pragma once
@@ -31,16 +31,14 @@
 namespace chip {
 namespace Inet {
 
-class DLL_EXPORT EndPointImplNetworkFramework : public EndPointBase
+class DLL_EXPORT EndPointStateNetworkFramework
 {
 protected:
-    EndPointImplNetworkFramework(InetLayer & inetLayer, void * appState = nullptr) : EndPointBase(inetLayer, appState) {}
+    EndPointStateNetworkFramework() {}
 
     nw_parameters_t mParameters;
     IPAddressType mAddrType; /**< Protocol family, i.e. IPv4 or IPv6. */
 };
 
-using EndPointBasis = EndPointImplNetworkFramework;
-
 } // namespace Inet
 } // namespace chip

src/inet/EndPointBasisImplSockets.h → src/inet/EndPointStateSockets.h

@@ -17,7 +17,7 @@
  */
 
 /**
- *  Sockets implementation of EndPointBase.
+ *  Shared state for socket implementations of TCPEndPoint and UDPEndPoint.
  */
 
 #pragma once
@@ -30,20 +30,16 @@
 namespace chip {
 namespace Inet {
 
-class DLL_EXPORT EndPointImplSockets : public EndPointBase
+class DLL_EXPORT EndPointStateSockets
 {
 protected:
-    EndPointImplSockets(InetLayer & inetLayer, void * appState = nullptr) :
-        EndPointBase(inetLayer, appState), mSocket(kInvalidSocketFd)
-    {}
+    EndPointStateSockets() : mSocket(kInvalidSocketFd) {}
 
     static constexpr int kInvalidSocketFd = -1;
     int mSocket;                     /**< Encapsulated socket descriptor. */
     IPAddressType mAddrType;         /**< Protocol family, i.e. IPv4 or IPv6. */
     System::SocketWatchToken mWatch; /**< Socket event watcher */
 };
 
-using EndPointBasis = EndPointImplSockets;
-
 } // namespace Inet
 } // namespace chip

src/inet/InetLayer.cpp

@@ -150,7 +150,7 @@ CHIP_ERROR InetLayer::Shutdown()
 
 #if INET_CONFIG_ENABLE_TCP_ENDPOINT
     // Abort all TCP endpoints owned by this instance.
-    TCPEndPoint::sPool.ForEachActiveObject([&](TCPEndPoint * lEndPoint) {
+    TCPEndPointImpl::sPool.ForEachActiveObject([&](TCPEndPoint * lEndPoint) {
         if ((lEndPoint != nullptr) && &lEndPoint->Layer() == this)
         {
             lEndPoint->Abort();
@@ -161,7 +161,7 @@ CHIP_ERROR InetLayer::Shutdown()
 
 #if INET_CONFIG_ENABLE_UDP_ENDPOINT
     // Close all UDP endpoints owned by this instance.
-    UDPEndPoint::sPool.ForEachActiveObject([&](UDPEndPoint * lEndPoint) {
+    UDPEndPointImpl::sPool.ForEachActiveObject([&](UDPEndPoint * lEndPoint) {
         if ((lEndPoint != nullptr) && &lEndPoint->Layer() == this)
         {
             lEndPoint->Close();
@@ -206,7 +206,7 @@ bool InetLayer::IsIdleTimerRunning()
     bool timerRunning = false;
 
     // See if there are any TCP connections with the idle timer check in use.
-    TCPEndPoint::sPool.ForEachActiveObject([&](TCPEndPoint * lEndPoint) {
+    TCPEndPointImpl::sPool.ForEachActiveObject([&](TCPEndPoint * lEndPoint) {
         if ((lEndPoint != nullptr) && (lEndPoint->mIdleTimeout != 0))
         {
             timerRunning = true;
@@ -245,7 +245,7 @@ CHIP_ERROR InetLayer::NewTCPEndPoint(TCPEndPoint ** retEndPoint)
 
     VerifyOrReturnError(mLayerState.IsInitialized(), CHIP_ERROR_INCORRECT_STATE);
 
-    *retEndPoint = TCPEndPoint::sPool.CreateObject(*this);
+    *retEndPoint = TCPEndPointImpl::sPool.CreateObject(*this);
     if (*retEndPoint == nullptr)
     {
         ChipLogError(Inet, "%s endpoint pool FULL", "TCP");
@@ -284,7 +284,7 @@ CHIP_ERROR InetLayer::NewUDPEndPoint(UDPEndPoint ** retEndPoint)
 
     VerifyOrReturnError(mLayerState.IsInitialized(), CHIP_ERROR_INCORRECT_STATE);
 
-    *retEndPoint = UDPEndPoint::sPool.CreateObject(*this);
+    *retEndPoint = UDPEndPointImpl::sPool.CreateObject(*this);
     if (*retEndPoint == nullptr)
     {
         ChipLogError(Inet, "%s endpoint pool FULL", "UDP");
@@ -303,7 +303,7 @@ void InetLayer::HandleTCPInactivityTimer(chip::System::Layer * aSystemLayer, voi
     InetLayer & lInetLayer = *reinterpret_cast<InetLayer *>(aAppState);
     bool lTimerRequired    = lInetLayer.IsIdleTimerRunning();
 
-    TCPEndPoint::sPool.ForEachActiveObject([&](TCPEndPoint * lEndPoint) {
+    TCPEndPointImpl::sPool.ForEachActiveObject([&](TCPEndPoint * lEndPoint) {
         if (&lEndPoint->Layer() != &lInetLayer)
             return true;
         if (!lEndPoint->IsConnected())