# HG changeset patch
# User Tommaso Pecorella <tommaso.pecorella@unifi.it>
# Date 1464223478 -7200
# Parent  39abf517d0106ca6aaedf2d2d083189f37f50f4f
network: (fixes #2078) Packet metadata disabling on a per-packet basis

diff --git a/RELEASE_NOTES b/RELEASE_NOTES
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -35,6 +35,7 @@
 - Bug 1939 - Aggregating the same object to two nodes produce unexpected results
 - Bug 1977 - v4Ping verbose output when not explicitly stopped
 - Bug 2057 - ARP and Ndisc caches should be updated by receiving valid L3 packets
+- Bug 2078 - Packet metadata disabling on a per-packet basis
 - Bug 2346 - SixLowPan ConpressionThreshold can be violated.
 - Bug 2329 - TCP Veno implementation
 - Bug 2333 - TCP Scalable implementation
diff --git a/src/internet/model/icmpv6-header.cc b/src/internet/model/icmpv6-header.cc
--- a/src/internet/model/icmpv6-header.cc
+++ b/src/internet/model/icmpv6-header.cc
@@ -1133,6 +1133,7 @@
   i.ReadNtohU32 ();
   i.Read (data, length);
   m_packet = Create<Packet> (data, length);
+  m_packet->DisableMetadata ();
 
   delete[] data;
   return GetSerializedSize ();
diff --git a/src/network/model/packet-metadata.cc b/src/network/model/packet-metadata.cc
--- a/src/network/model/packet-metadata.cc
+++ b/src/network/model/packet-metadata.cc
@@ -49,6 +49,18 @@
 }
 
 void 
+PacketMetadata::Disable (void)
+{
+  NS_LOG_FUNCTION_NOARGS ();
+  m_enabledOnPacket = false;
+  m_data->m_count--;
+  if (m_data->m_count == 0)
+    {
+      PacketMetadata::Recycle (m_data);
+    }
+}
+
+void
 PacketMetadata::Enable (void)
 {
   NS_LOG_FUNCTION_NOARGS ();
@@ -669,6 +681,10 @@
       m_metadataSkipped = true;
       return;
     }
+  if (!m_enabledOnPacket)
+    {
+      return;
+    }
 
   struct PacketMetadata::SmallItem item;
   item.next = m_head;
@@ -691,6 +707,11 @@
       m_metadataSkipped = true;
       return;
     }
+  if (!m_enabledOnPacket)
+    {
+      return;
+    }
+
   struct PacketMetadata::SmallItem item;
   struct PacketMetadata::ExtraItem extraItem;
   uint32_t read = ReadItems (m_head, &item, &extraItem);
@@ -739,6 +760,11 @@
       m_metadataSkipped = true;
       return;
     }
+  if (!m_enabledOnPacket)
+    {
+      return;
+    }
+
   struct PacketMetadata::SmallItem item;
   item.next = 0xffff;
   item.prev = m_tail;
@@ -761,6 +787,11 @@
       m_metadataSkipped = true;
       return;
     }
+  if (!m_enabledOnPacket)
+    {
+      return;
+    }
+
   struct PacketMetadata::SmallItem item;
   struct PacketMetadata::ExtraItem extraItem;
   uint32_t read = ReadItems (m_tail, &item, &extraItem);
@@ -808,6 +839,21 @@
       m_metadataSkipped = true;
       return;
     }
+  if (!m_enabledOnPacket || !o.m_enabledOnPacket)
+    {
+      if (m_enabledOnPacket)
+        {
+          m_data->m_count--;
+          if (m_data->m_count == 0)
+            {
+              PacketMetadata::Recycle (m_data);
+            }
+        }
+
+      m_enabledOnPacket = false;
+      return;
+    }
+
   if (m_tail == 0xffff)
     {
       // We have no items so 'AddAtEnd' is 
diff --git a/src/network/model/packet-metadata.h b/src/network/model/packet-metadata.h
--- a/src/network/model/packet-metadata.h
+++ b/src/network/model/packet-metadata.h
@@ -152,9 +152,26 @@
   };
 
   /**
-   * \brief Enable the packet metadata
+   * \brief Enable the packet metadata on all packets.
+   *
+   * Packet metadata must be enabled at the start of the
+   * simulation, before any Packet exchange.
+   * All the packets will have their metadata enabled,
+   * except the ones where metadata are explicitly
+   * disabled (\see Disable)
+   *
    */
   static void Enable (void);
+
+  /**
+   * \brief Disable, on a per-packet basis, the use of metadata.
+   *
+   * This must be used if metadata checking is globally enabled,
+   * and if the packet is built in a manner (e.g. from a raw
+   * byte buffer) such that the metadata is incomplete.
+   */
+  void Disable (void);
+
   /**
    * \brief Enable the packet metadata checking
    */
@@ -657,7 +674,8 @@
   static void Deallocate (struct PacketMetadata::Data *data);
 
   static DataFreeList m_freeList; //!< the metadata data storage
-  static bool m_enable; //!< Enable the packet metadata
+  static bool m_enable; //!< Enable the packet metadata at global level
+  bool m_enabledOnPacket; //!< Enable the packet metadata at packet level
   static bool m_enableChecking; //!< Enable the packet metadata checking
 
   /**
@@ -687,7 +705,8 @@
 namespace ns3 {
 
 PacketMetadata::PacketMetadata (uint64_t uid, uint32_t size)
-  : m_data (PacketMetadata::Create (10)),
+  : m_enabledOnPacket (m_enable),
+    m_data (PacketMetadata::Create (10)),
     m_head (0xffff),
     m_tail (0xffff),
     m_used (0),
@@ -700,7 +719,8 @@
     }
 }
 PacketMetadata::PacketMetadata (PacketMetadata const &o)
-  : m_data (o.m_data),
+  : m_enabledOnPacket (o.m_enabledOnPacket),
+    m_data (o.m_data),
     m_head (o.m_head),
     m_tail (o.m_tail),
     m_used (o.m_used),
@@ -713,6 +733,7 @@
 PacketMetadata &
 PacketMetadata::operator = (PacketMetadata const& o)
 {
+  m_enabledOnPacket = o.m_enabledOnPacket;
   if (m_data != o.m_data) 
     {
       // not self assignment
diff --git a/src/network/model/packet.cc b/src/network/model/packet.cc
--- a/src/network/model/packet.cc
+++ b/src/network/model/packet.cc
@@ -247,6 +247,12 @@
   m_nixVector = nixVector;
 }
 
+void
+Packet::DisableMetadata (void)
+{
+  m_metadata.Disable ();
+}
+
 Ptr<NixVector>
 Packet::GetNixVector (void) const
 {
@@ -752,11 +758,11 @@
 
   size -= metaSize;
 
-  uint32_t metadataDeserialized = 
+  uint32_t metadataDeserialized =
     m_metadata.Deserialize (reinterpret_cast<const uint8_t *> (p), metaSize);
   if (!metadataDeserialized)
     {
-      // meta-data not deserialized 
+      // meta-data not deserialized
       // completely
       return 0;
     }
diff --git a/src/network/model/packet.h b/src/network/model/packet.h
--- a/src/network/model/packet.h
+++ b/src/network/model/packet.h
@@ -276,6 +276,10 @@
    * The input data is copied: the input
    * buffer is untouched.
    *
+   * If the buffer also contains headers or trailers and these
+   * must be later removed, it is advisable to use
+   * Packet::SetDirtyMetadata as well.
+   *
    * \param buffer the data to store in the packet.
    * \param size the size of the input buffer.
    */
@@ -526,6 +530,18 @@
   uint32_t Serialize (uint8_t* buffer, uint32_t maxSize) const;
 
   /**
+   * \brief Disable, on a per-packet basis, the use of metadata.
+   *
+   * This must be used if metadata checking is globally enabled,
+   * and if the packet is built in a way such that the metadata
+   * is incomplete (e.g. from a raw byte buffer).
+   *
+   * \warning If a packet with disabled metadata is added to another,
+   * the resulting packet will have its metadata disabled.
+   */
+  void DisableMetadata (void);
+
+  /**
    * \brief Tag each byte included in this packet with a new byte tag.
    *
    * \param tag the new tag to add to this packet
@@ -542,6 +558,7 @@
    * packet).
    */
   void AddByteTag (const Tag &tag) const;
+
   /**
    * \brief Retiurns an iterator over the set of byte tags included in this packet
    *