semi-real multicast hardware addresses

src/devices/csma/csma-net-device.cc

@@ -132,7 +132,7 @@ CsmaNetDevice::Init(bool sendEnable, bool receiveEnable)
   m_queue = 0;
 
   EnableBroadcast (Eui48Address ("ff:ff:ff:ff:ff:ff"));
-  EnableMulticast();
+  EnableMulticast (Eui48Address ("01:00:5e:00:00:00"));
 
   SetSendEnable (sendEnable);
   SetReceiveEnable (receiveEnable);
@@ -500,10 +500,11 @@ CsmaNetDevice::Receive (const Packet& packet)
   EthernetHeader header (false);
   EthernetTrailer trailer;
   Eui48Address broadcast;
+  Eui48Address multicast;
   Eui48Address destination;
   Packet p = packet;
 
-  NS_DEBUG ("CsmaNetDevice::Receive UID is (" << p.GetUid() << ")");
+  NS_DEBUG ("CsmaNetDevice::Receive ():  UID is " << p.GetUid());
 
   // Only receive if send side of net device is enabled
   if (!IsReceiveEnabled())
@@ -522,12 +523,25 @@ CsmaNetDevice::Receive (const Packet& packet)
   trailer.CheckFcs(p);
   p.RemoveHeader(header);
 
+  NS_DEBUG ("CsmaNetDevice::Receive ():  Pkt destination is " << 
+    header.GetDestination ());
+//
+// XXX BUGBUG
+//
+// An IP host group address is mapped to an Ethernet multicast address
+// by placing the low-order 23-bits of the IP address into the low-order
+// 23 bits of the Ethernet multicast address 01-00-5E-00-00-00 (hex).
+//
+// Need to mask off the appropriate multicast bits.
+//
+  multicast = Eui48Address::ConvertFrom (GetMulticast ());
   broadcast = Eui48Address::ConvertFrom (GetBroadcast ());
   destination = Eui48Address::ConvertFrom (GetAddress ());
   if ((header.GetDestination() != broadcast) &&
+      (header.GetDestination() != multicast) &&
       (header.GetDestination() != destination))
     {
-      // not for us.
+      NS_DEBUG ("CsmaNetDevice::Receive ():  Dropping pkt ");
       m_dropTrace (p);
       return;
     }

src/devices/point-to-point/point-to-point-net-device.cc

@@ -68,11 +68,14 @@ PointToPointNetDevice::PointToPointNetDevice (Ptr<Node> node,
 {
   NS_DEBUG ("PointToPointNetDevice::PointToPointNetDevice (" << node << ")");
 
-  // BUGBUG FIXME
-  //
-  // You _must_ support broadcast to get any sort of packet from the ARP layer.
+// BUGBUG FIXME
+//
+// You _must_ support broadcast to get any sort of packet from the ARP layer.
   EnableBroadcast (Eui48Address ("ff:ff:ff:ff:ff:ff"));
-  EnableMulticast();
+//
+// Randomly pick the ethernet multicast address base
+//
+  EnableMulticast (Eui48Address ("01:00:5e:00:00:00"));
   EnablePointToPoint();
 }
 

src/internet-node/arp-ipv4-interface.cc

@@ -84,9 +84,18 @@ ArpIpv4Interface::SendTo (Packet p, Ipv4Address dest)
       else if (dest.IsMulticast ())
         {
           NS_DEBUG ("ArpIpv4Interface::SendTo (): IsMulticast");
-          // XXX BUGBUG
-          // Need real multicast addresses
-          hardwareDestination = GetDevice ()->GetBroadcast ();
+          NS_ASSERT_MSG(GetDevice ()->IsMulticast (),
+            "ArpIpv4Interface::SendTo (): Sending multicast packet over "
+            "non-multicast device");
+// XXX
+// 
+// An IP host group address is mapped to an Ethernet multicast address
+// by placing the low-order 23-bits of the IP address into the low-order
+// 23 bits of the Ethernet multicast address 01-00-5E-00-00-00 (hex).
+//
+// Currently no easy way to or bit from Ipv4Address into Address
+//
+          hardwareDestination = GetDevice ()->GetMulticast ();
           found = true;
         }
       else

src/internet-node/ipv4-l3-protocol.cc

@@ -288,12 +288,13 @@ Ipv4L3Protocol::Lookup (
 // want to force users to construct a route in order to get packets out of a
 // node, so there will have been no route found and it is left to us to send
 // the packet.  What we'll do is to send the multicast out all of the 
-// interfaces on this node.
+// interfaces on this node.  Note that we start with interface 1 since we 
+// don't particularly want to send the packet out the loopback.
 //
       NS_DEBUG ("Ipv4StaticRouting::Lookup (): "
         "Local source. Flooding multicast packet");
 
-      for (uint32_t i = 0; i < GetNInterfaces (); ++i)
+      for (uint32_t i = 1; i < GetNInterfaces (); ++i)
         {
           Packet p = packet;
           Ipv4Header h = ipHeader;

src/node/net-device.cc

@@ -113,6 +113,7 @@ NetDevice::IsBroadcast (void) const
 {
   return m_isBroadcast;
 }
+
 Address const &
 NetDevice::GetBroadcast (void) const
 {
@@ -139,10 +140,18 @@ NetDevice::IsMulticast (void) const
   return m_isMulticast;
 }
 
+Address const &
+NetDevice::GetMulticast (void) const
+{
+  NS_ASSERT (m_isMulticast);
+  return m_multicast;
+}
+
 void
-NetDevice::EnableMulticast (void)
+NetDevice::EnableMulticast (Address multicast)
 {
   m_isMulticast = true;
+  m_multicast = multicast;
 }
 
 void

src/node/net-device.h

@@ -138,10 +138,21 @@ public:
    * not true.
    */
   Address const &GetBroadcast (void) const;
+
   /**
    * \return value of m_isMulticast flag
    */
   bool IsMulticast (void) const;
+
+  /**
+   * \return the multicast address supported by
+   *         this netdevice.
+   *
+   * Calling this method is invalid if IsMulticast returns
+   * not true.
+   */
+  Address const &GetMulticast (void) const;
+
   /**
    * \return value of m_isPointToPoint flag
    */
@@ -212,9 +223,10 @@ public:
    */
   void DisableBroadcast (void);
   /**
-   * Set m_isMulticast flag to true
+   * Enable multicast support. This method should be
+   * called by subclasses from their constructor
    */
-  void EnableMulticast (void);
+  void EnableMulticast (Address multicast);
   /**
    * Set m_isMulticast flag to false
    */
@@ -303,6 +315,7 @@ public:
   uint16_t      m_ifIndex;
   Address       m_address;
   Address       m_broadcast;
+  Address       m_multicast;
   uint16_t      m_mtu;
   bool          m_isUp;
   bool          m_isBroadcast;