applications: Add common class for sink applications

Proposed by Sharan Naribole

src/applications/CMakeLists.txt

@@ -15,6 +15,7 @@ build_lib(
     model/seq-ts-echo-header.cc
     model/seq-ts-header.cc
     model/seq-ts-size-header.cc
+    model/sink-application.cc
     model/source-application.cc
     model/three-gpp-http-client.cc
     model/three-gpp-http-header.cc
@@ -40,6 +41,7 @@ build_lib(
     model/seq-ts-echo-header.h
     model/seq-ts-header.h
     model/seq-ts-size-header.h
+    model/sink-application.h
     model/source-application.h
     model/three-gpp-http-client.h
     model/three-gpp-http-header.h

src/applications/model/sink-application.cc

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2024 DERONNE SOFTWARE ENGINEERING
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Author: Sébastien Deronne <sebastien.deronne@gmail.com>
+ */
+
+#include "sink-application.h"
+
+#include "ns3/log.h"
+#include "ns3/uinteger.h"
+
+namespace ns3
+{
+
+NS_LOG_COMPONENT_DEFINE("SinkApplication");
+
+NS_OBJECT_ENSURE_REGISTERED(SinkApplication);
+
+TypeId
+SinkApplication::GetTypeId()
+{
+    static TypeId tid =
+        TypeId("ns3::SinkApplication")
+            .SetParent<Application>()
+            .SetGroupName("Applications")
+            .AddAttribute(
+                "Local",
+                "The Address on which to Bind the rx socket. "
+                "If it is not specified, it will listen to any address.",
+                AddressValue(),
+                MakeAddressAccessor(&SinkApplication::SetLocal, &SinkApplication::GetLocal),
+                MakeAddressChecker())
+            .AddAttribute(
+                "Port",
+                "Port on which the application listens for incoming packets.",
+                UintegerValue(INVALID_PORT),
+                MakeUintegerAccessor(&SinkApplication::SetPort, &SinkApplication::GetPort),
+                MakeUintegerChecker<uint32_t>());
+    return tid;
+}
+
+SinkApplication::SinkApplication(uint16_t defaultPort)
+    : m_port{defaultPort}
+{
+    NS_LOG_FUNCTION(this << defaultPort);
+}
+
+SinkApplication::~SinkApplication()
+{
+    NS_LOG_FUNCTION(this);
+}
+
+void
+SinkApplication::SetLocal(const Address& addr)
+{
+    NS_LOG_FUNCTION(this << addr);
+    m_local = addr;
+}
+
+Address
+SinkApplication::GetLocal() const
+{
+    return m_local;
+}
+
+void
+SinkApplication::SetPort(uint32_t port)
+{
+    NS_LOG_FUNCTION(this << port);
+    if (port == INVALID_PORT)
+    {
+        return;
+    }
+    m_port = port;
+}
+
+uint32_t
+SinkApplication::GetPort() const
+{
+    return m_port;
+}
+
+} // Namespace ns3

src/applications/model/sink-application.h

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2024 DERONNE SOFTWARE ENGINEERING
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Author: Sébastien Deronne <sebastien.deronne@gmail.com>
+ */
+
+#ifndef SINK_APPLICATION_H
+#define SINK_APPLICATION_H
+
+#include "ns3/address.h"
+#include "ns3/application.h"
+
+#include <limits>
+
+namespace ns3
+{
+
+/**
+ * \ingroup applications
+ * \brief Base class for sink applications.
+ *
+ * This class can be used as a base class for sink applications.
+ * A sink application is an application that is primarily used to only receive or echo packets.
+ *
+ * The main purpose of this base class application public API is to hold attributes for the local
+ * (IPv4 or IPv6) address and port to bind to.
+ *
+ * There are three ways that the port value can be configured. First, and most typically, through
+ * the use of a socket address (InetSocketAddress or Inet6SocketAddress) that is configured as the
+ * Local address to bind to. Second, through direct configuration of the Port attribute. Third,
+ * through the use of an optional constructor argument. If multiple of these port configuration
+ * methods are used, it is up to subclass definition which one takes precedence; in the existing
+ * subclasses in this directory, the port value configured in the Local socket address (if a socket
+ * address is configured there) will take precedence.
+ */
+class SinkApplication : public Application
+{
+  public:
+    /**
+     * \brief Get the type ID.
+     * \return the object TypeId
+     */
+    static TypeId GetTypeId();
+
+    /**
+     * Constructor
+     *
+     * \param defaultPort the default port number
+     */
+    SinkApplication(uint16_t defaultPort = 0);
+    ~SinkApplication() override;
+
+    static constexpr uint32_t INVALID_PORT{std::numeric_limits<uint32_t>::max()}; //!< invalid port
+
+  protected:
+    Address m_local; //!< Local address to bind to (address and port)
+    uint32_t m_port; //!< Local port to bind to
+
+  private:
+    /**
+     * \brief set the local address
+     * \param addr local address
+     */
+    virtual void SetLocal(const Address& addr);
+
+    /**
+     * \brief get the local address
+     * \return the local address
+     */
+    Address GetLocal() const;
+
+    /**
+     * \brief set the server port
+     * \param port server port
+     */
+    virtual void SetPort(uint32_t port);
+
+    /**
+     * \brief get the server port
+     * \return the server port
+     */
+    uint32_t GetPort() const;
+};
+
+} // namespace ns3
+
+#endif /* SINK_APPLICATION_H */