# HG changeset patch
# User Tommaso Pecorella <tommaso.pecorella@unifi.it>
# Date 1456573017 -3600
# Parent  48d97b9d2ef242e0156ed54ab59270738aeacbfc
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
@@ -64,6 +64,7 @@
 - Bug 2003 - Missing DSSS short PLCP preamble
 - Bug 2041 - TCP RTO needs unit tests
 - Bug 2068 - Timestamp option conforms to RFC 7323
+- Bug 2078 - Packet metadata disabling on a per-packet basis
 - Bug 2116 - refactoring aggregation API
 - Bug 2120 - 802.11g networks are not compatible with 802.11b clients
 - Bug 2141 - TCP DataSent callback now correctly notifies sent data, without missing bytes in particular conditions
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->SetDirtyMetadata ();
 
   delete[] data;
   return GetSerializedSize ();
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
@@ -138,6 +138,7 @@
      * global UID
      */
     m_metadata (static_cast<uint64_t> (Simulator::GetSystemId ()) << 32 | m_globalUid, 0),
+    m_dirtyMetadata (false),
     m_nixVector (0)
 {
   m_globalUid++;
@@ -147,7 +148,8 @@
   : m_buffer (o.m_buffer),
     m_byteTagList (o.m_byteTagList),
     m_packetTagList (o.m_packetTagList),
-    m_metadata (o.m_metadata)
+    m_metadata (o.m_metadata),
+    m_dirtyMetadata (o.m_dirtyMetadata)
 {
   o.m_nixVector ? m_nixVector = o.m_nixVector->Copy ()
     : m_nixVector = 0;
@@ -164,6 +166,7 @@
   m_byteTagList = o.m_byteTagList;
   m_packetTagList = o.m_packetTagList;
   m_metadata = o.m_metadata;
+  m_dirtyMetadata = o.m_dirtyMetadata;
   o.m_nixVector ? m_nixVector = o.m_nixVector->Copy () 
     : m_nixVector = 0;
   return *this;
@@ -180,6 +183,7 @@
      * global UID
      */
     m_metadata (static_cast<uint64_t> (Simulator::GetSystemId ()) << 32 | m_globalUid, size),
+    m_dirtyMetadata (false),
     m_nixVector (0)
 {
   m_globalUid++;
@@ -189,6 +193,7 @@
     m_byteTagList (),
     m_packetTagList (),
     m_metadata (0,0),
+    m_dirtyMetadata (false),
     m_nixVector (0)
 {
   NS_ASSERT (magic);
@@ -206,6 +211,7 @@
      * global UID
      */
     m_metadata (static_cast<uint64_t> (Simulator::GetSystemId ()) << 32 | m_globalUid, size),
+    m_dirtyMetadata (false),
     m_nixVector (0)
 {
   m_globalUid++;
@@ -220,6 +226,7 @@
     m_byteTagList (byteTagList),
     m_packetTagList (packetTagList),
     m_metadata (metadata),
+    m_dirtyMetadata (false),
     m_nixVector (0)
 {
 }
@@ -247,6 +254,12 @@
   m_nixVector = nixVector;
 }
 
+void
+Packet::SetDirtyMetadata (void)
+{
+  m_dirtyMetadata = true;
+}
+
 Ptr<NixVector>
 Packet::GetNixVector (void) const
 {
@@ -271,7 +284,10 @@
   NS_LOG_FUNCTION (this << header.GetInstanceTypeId ().GetName () << deserialized);
   m_buffer.RemoveAtStart (deserialized);
   m_byteTagList.Adjust (-deserialized);
-  m_metadata.RemoveHeader (header, deserialized);
+  if (!m_dirtyMetadata)
+    {
+      m_metadata.RemoveHeader (header, deserialized);
+    }
   return deserialized;
 }
 uint32_t
@@ -298,7 +314,10 @@
   uint32_t deserialized = trailer.Deserialize (m_buffer.End ());
   NS_LOG_FUNCTION (this << trailer.GetInstanceTypeId ().GetName () << deserialized);
   m_buffer.RemoveAtEnd (deserialized);
-  m_metadata.RemoveTrailer (trailer, deserialized);
+  if (!m_dirtyMetadata)
+    {
+      m_metadata.RemoveTrailer (trailer, deserialized);
+    }
   return deserialized;
 }
 uint32_t
@@ -752,11 +771,11 @@
 
   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 +530,16 @@
   uint32_t Serialize (uint8_t* buffer, uint32_t maxSize) const;
 
   /**
+   * Prevents the packet header and trailer removal from trying to
+   * remove also non-existent metadata.
+   *
+   * A packet with a valid header (or trailer) can be created by direct
+   * creation of a packet from a buffer with a proper header.
+   * This is typical of ICMP Destination Unreachable.
+   */
+  void SetDirtyMetadata (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 +556,7 @@
    * packet).
    */
   void AddByteTag (const Tag &tag) const;
+
   /**
    * \brief Retiurns an iterator over the set of byte tags included in this packet
    *
@@ -717,6 +732,7 @@
   ByteTagList m_byteTagList;      //!< the ByteTag list
   PacketTagList m_packetTagList;  //!< the packet's Tag list
   PacketMetadata m_metadata;      //!< the packet's metadata
+  bool m_dirtyMetadata;           //!< the packet's metadata are not check-safe
 
   /* Please see comments above about nix-vector */
   Ptr<NixVector> m_nixVector; //!< the packet's Nix vector