internet: refactor how headers are built during fragmentation

src/internet/model/ipv6-extension.cc

@@ -513,11 +513,16 @@ Ipv6ExtensionFragment::GetFragments(Ptr<Packet> packet,
         }
         else if (nextHeader == Ipv6Header::IPV6_EXT_ROUTING)
         {
-            uint8_t buf[2];
+            Ptr<Ipv6ExtensionRoutingDemux> ipv6ExtensionRoutingDemux =
+                GetNode()->GetObject<Ipv6ExtensionRoutingDemux>();
+
+            uint8_t buf[4];
             p->CopyData(buf, sizeof(buf));
-            uint8_t numberAddress = buf[1] / 2;
-            Ipv6ExtensionLooseRoutingHeader* routingHeader = new Ipv6ExtensionLooseRoutingHeader();
-            routingHeader->SetNumberAddress(numberAddress);
+            uint8_t routingType = buf[2];
+
+            Ipv6ExtensionRoutingHeader* routingHeader =
+                ipv6ExtensionRoutingDemux->GetExtensionRoutingHeaderPtr(routingType);
+
             p->RemoveHeader(*routingHeader);
 
             nextHeader = routingHeader->GetNextHeader();
@@ -885,6 +890,12 @@ Ipv6ExtensionRouting::GetTypeRouting() const
     return 0;
 }
 
+Ipv6ExtensionRoutingHeader*
+Ipv6ExtensionRouting::GetExtensionRoutingHeaderPtr()
+{
+    return nullptr;
+}
+
 uint8_t
 Ipv6ExtensionRouting::Process(Ptr<Packet>& packet,
                               uint8_t offset,
@@ -1014,15 +1025,30 @@ Ipv6ExtensionRoutingDemux::Insert(Ptr<Ipv6ExtensionRouting> extensionRouting)
 Ptr<Ipv6ExtensionRouting>
 Ipv6ExtensionRoutingDemux::GetExtensionRouting(uint8_t typeRouting)
 {
-    for (Ipv6ExtensionRoutingList_t::iterator i = m_extensionsRouting.begin();
-         i != m_extensionsRouting.end();
-         i++)
+    for (const auto& extRouting : m_extensionsRouting)
     {
-        if ((*i)->GetTypeRouting() == typeRouting)
+        if (extRouting->GetTypeRouting() == typeRouting)
         {
-            return *i;
+            return extRouting;
         }
     }
+
+    return nullptr;
+}
+
+Ipv6ExtensionRoutingHeader*
+Ipv6ExtensionRoutingDemux::GetExtensionRoutingHeaderPtr(uint8_t typeRouting)
+{
+    NS_LOG_FUNCTION(this << typeRouting);
+
+    for (const auto& extRouting : m_extensionsRouting)
+    {
+        if (extRouting->GetTypeRouting() == typeRouting)
+        {
+            return extRouting->GetExtensionRoutingHeaderPtr();
+        }
+    }
+
     return nullptr;
 }
 
@@ -1059,6 +1085,12 @@ Ipv6ExtensionLooseRouting::GetTypeRouting() const
     return TYPE_ROUTING;
 }
 
+Ipv6ExtensionRoutingHeader*
+Ipv6ExtensionLooseRouting::GetExtensionRoutingHeaderPtr()
+{
+    return new Ipv6ExtensionLooseRoutingHeader();
+}
+
 uint8_t
 Ipv6ExtensionLooseRouting::Process(Ptr<Packet>& packet,
                                    uint8_t offset,
@@ -1089,9 +1121,7 @@ Ipv6ExtensionLooseRouting::Process(Ptr<Packet>& packet,
     // Get the number of routers' address field
     uint8_t buf[2];
     p->CopyData(buf, sizeof(buf));
-    uint8_t numberAddress = buf[1] / 2;
     Ipv6ExtensionLooseRoutingHeader routingHeader;
-    routingHeader.SetNumberAddress(numberAddress);
     p->RemoveHeader(routingHeader);
 
     if (nextHeader)

src/internet/model/ipv6-extension.h

@@ -20,6 +20,7 @@
 #ifndef IPV6_EXTENSION_H
 #define IPV6_EXTENSION_H
 
+#include "ipv6-extension-header.h"
 #include "ipv6-interface.h"
 
 #include "ns3/buffer.h"
@@ -515,6 +516,13 @@ class Ipv6ExtensionRouting : public Ipv6Extension
      */
     virtual uint8_t GetTypeRouting() const;
 
+    /**
+     * \brief Get a pointer to a new routing extension header.
+     * The ownership is transferred to the caller.
+     * \return a pointer to a new routing extension header.
+     */
+    virtual Ipv6ExtensionRoutingHeader* GetExtensionRoutingHeaderPtr();
+
     uint8_t Process(Ptr<Packet>& packet,
                     uint8_t offset,
                     const Ipv6Header& ipv6Header,
@@ -568,6 +576,14 @@ class Ipv6ExtensionRoutingDemux : public Object
      */
     Ptr<Ipv6ExtensionRouting> GetExtensionRouting(uint8_t typeRouting);
 
+    /**
+     * \brief Get a pointer to a new routing extension header corresponding
+     * to typeRouting. The ownership is transferred to the caller.
+     * \param typeRouting the number of the routing extension to retrieve
+     * \return a pointer to a new routing extension header matching IPv6 routing extension
+     */
+    Ipv6ExtensionRoutingHeader* GetExtensionRoutingHeaderPtr(uint8_t typeRouting);
+
     /**
      * \brief Remove a routing extension from this demux.
      * \param extensionRouting pointer on the extension to remove
@@ -632,6 +648,8 @@ class Ipv6ExtensionLooseRouting : public Ipv6ExtensionRouting
      */
     uint8_t GetTypeRouting() const override;
 
+    Ipv6ExtensionRoutingHeader* GetExtensionRoutingHeaderPtr() override;
+
     uint8_t Process(Ptr<Packet>& packet,
                     uint8_t offset,
                     const Ipv6Header& ipv6Header,