bug 63: allow enabling or disabling ip forwarding on a per-interface basis

src/node/ipv4-routing-protocol.h

@@ -51,7 +51,7 @@ public:
   typedef Callback<void, Ptr<Ipv4Route>, Ptr<const Packet>, const Ipv4Header &> UnicastForwardCallback;
   typedef Callback<void, Ptr<Ipv4MulticastRoute>, Ptr<const Packet>, const Ipv4Header &> MulticastForwardCallback;
   typedef Callback<void, Ptr<const Packet>, const Ipv4Header &, uint32_t > LocalDeliverCallback;
-  typedef Callback<void, Ptr<const Packet>, const Ipv4Header &> ErrorCallback;
+  typedef Callback<void, Ptr<const Packet>, const Ipv4Header &, Socket::SocketErrno > ErrorCallback;
   
   /**
    * \brief Query routing cache for an existing route, for an outbound packet

src/node/ipv4.cc

@@ -32,7 +32,7 @@ Ipv4::GetTypeId (void)
 {
   static TypeId tid = TypeId ("ns3::Ipv4")
     .SetParent<Object> ()
-    .AddAttribute ("IpForward", "If enabled, node can act as unicast router.",
+    .AddAttribute ("IpForward", "Globally enable or disable IP forwarding for all current and future Ipv4 devices.",
                    BooleanValue (true),
                    MakeBooleanAccessor (&Ipv4::SetIpForward,
                                         &Ipv4::GetIpForward),

src/node/ipv4.h

@@ -235,6 +235,20 @@ public:
    */
   virtual void SetDown (uint32_t interface) = 0;
 
+  /**
+   * \param interface Interface number of Ipv4 interface
+   * \returns true if IP forwarding enabled for input datagrams on this device
+   */
+  virtual bool IsForwarding (uint32_t interface) const = 0;
+
+  /**
+   * \param interface Interface number of Ipv4 interface
+   * \param val Value to set the forwarding flag
+   * 
+   * If set to true, IP forwarding is enabled for input datagrams on this device
+   */
+  virtual void SetForwarding (uint32_t interface, bool val) = 0;
+
   static const uint32_t IF_ANY = 0xffffffff;
 
 private: