# HG changeset patch
# User Tom Henderson <tomh@tomh.org>
# Date 1496154324 25200
#      Tue May 30 07:25:24 2017 -0700
# Node ID 1dd3e78828daf63596b6c0276907dc2316c01c17
# Parent  34493978d2ae136daa59cc0f10eb33c2e210e68e
enable deserialization of variable-sized headers and trailers

diff -r 34493978d2ae -r 1dd3e78828da src/network/model/chunk.cc
--- a/src/network/model/chunk.cc	Sun May 28 22:22:41 2017 +0200
+++ b/src/network/model/chunk.cc	Tue May 30 07:25:24 2017 -0700
@@ -34,4 +34,12 @@
   return tid;
 }
 
+// This default implementation is provided for backward compatibility
+// reasons.  Subclasses should implement this method themselves.
+uint32_t
+Chunk::Deserialize (Buffer::Iterator start, Buffer::Iterator end)
+{
+  return Deserialize (start);
+}
+
 } // namespace ns3
diff -r 34493978d2ae -r 1dd3e78828da src/network/model/chunk.h
--- a/src/network/model/chunk.h	Sun May 28 22:22:41 2017 +0200
+++ b/src/network/model/chunk.h	Tue May 30 07:25:24 2017 -0700
@@ -42,12 +42,32 @@
 
   /**
    * \brief Deserialize the object from a buffer iterator
+   *
+   * This version of Deserialize can be used when the Chunk has a fixed
+   * size.  It should not be called for variable-sized Chunk derived types
+   * (but must be implemented, for historical reasons).
+   *
    * \param start the buffer iterator
    * \returns the number of deserialized bytes
    */
   virtual uint32_t Deserialize (Buffer::Iterator start) = 0;
 
   /**
+   * \brief Deserialize the object from a buffer iterator
+   *
+   * This version of Deserialize must be used when the Chunk has a variable
+   * size, because the bounds of the Chunk may not be known at the point
+   * of deserialization (e.g. a sequence of TLV fields).
+   *
+   * The size of the chunk should be start.GetDistanceFrom (end);
+   *
+   * \param start the starting point
+   * \param end the ending point
+   * \returns the number of deserialized bytes
+   */
+  virtual uint32_t Deserialize (Buffer::Iterator start, Buffer::Iterator end);
+
+  /**
    * \brief Print the object contents
    * \param os the output stream
    */
diff -r 34493978d2ae -r 1dd3e78828da src/network/model/header.h
--- a/src/network/model/header.h	Sun May 28 22:22:41 2017 +0200
+++ b/src/network/model/header.h	Tue May 30 07:25:24 2017 -0700
@@ -48,6 +48,8 @@
    */
   static TypeId GetTypeId (void);
   virtual ~Header ();
+
+  using Chunk::Deserialize;
   /**
    * \returns the expected size of the header.
    *
diff -r 34493978d2ae -r 1dd3e78828da src/network/model/packet.cc
--- a/src/network/model/packet.cc	Sun May 28 22:22:41 2017 +0200
+++ b/src/network/model/packet.cc	Tue May 30 07:25:24 2017 -0700
@@ -264,6 +264,19 @@
   m_metadata.AddHeader (header, size);
 }
 uint32_t
+Packet::RemoveHeader (Header &header, uint32_t size)
+{
+  Buffer::Iterator end;
+  end = m_buffer.Begin ();
+  end.Next (size);
+  uint32_t deserialized = header.Deserialize (m_buffer.Begin (), end);
+  NS_LOG_FUNCTION (this << header.GetInstanceTypeId ().GetName () << deserialized);
+  m_buffer.RemoveAtStart (deserialized);
+  m_byteTagList.Adjust (-deserialized);
+  m_metadata.RemoveHeader (header, deserialized);
+  return deserialized;
+}
+uint32_t
 Packet::RemoveHeader (Header &header)
 {
   uint32_t deserialized = header.Deserialize (m_buffer.Begin ());
@@ -280,6 +293,16 @@
   NS_LOG_FUNCTION (this << header.GetInstanceTypeId ().GetName () << deserialized);
   return deserialized;
 }
+uint32_t
+Packet::PeekHeader (Header &header, uint32_t size) const
+{
+  Buffer::Iterator end;
+  end = m_buffer.Begin ();
+  end.Next (size);
+  uint32_t deserialized = header.Deserialize (m_buffer.Begin (), end);
+  NS_LOG_FUNCTION (this << header.GetInstanceTypeId ().GetName () << deserialized);
+  return deserialized;
+}
 void
 Packet::AddTrailer (const Trailer &trailer)
 {
@@ -445,7 +468,22 @@
                 NS_ASSERT (instance != 0);
                 Chunk *chunk = dynamic_cast<Chunk *> (instance);
                 NS_ASSERT (chunk != 0);
-                chunk->Deserialize (item.current);
+                if (item.type == PacketMetadata::Item::HEADER)
+                  {
+                    Buffer::Iterator end = item.current;
+                    end.Next (item.currentSize); // move from start 
+                    chunk->Deserialize (item.current, end);
+                  }
+                else if (item.type == PacketMetadata::Item::TRAILER)
+                  {
+                    Buffer::Iterator start = item.current;
+                    start.Prev (item.currentSize); // move from end
+                    chunk->Deserialize (start, item.current);
+                  }
+                else
+                  {
+                    chunk->Deserialize (item.current);
+                  }    
                 chunk->Print (os);
                 delete chunk;
               }
diff -r 34493978d2ae -r 1dd3e78828da src/network/model/packet.h
--- a/src/network/model/packet.h	Sun May 28 22:22:41 2017 +0200
+++ b/src/network/model/packet.h	Tue May 30 07:25:24 2017 -0700
@@ -316,13 +316,26 @@
   /**
    * \brief Deserialize and remove the header from the internal buffer.
    *
-   * This method invokes Header::Deserialize.
+   * This method invokes Header::Deserialize (begin) and should be used for
+   * variable-length headers.
    *
    * \param header a reference to the header to remove from the internal buffer.
    * \returns the number of bytes removed from the packet.
    */
   uint32_t RemoveHeader (Header &header);
   /**
+   * \brief Deserialize and remove the header from the internal buffer.
+   *
+   * This method invokes Header::Deserialize (begin, end) and should be 
+   * used for variable-length headers (where the size is determined somehow
+   * by the caller).
+   *
+   * \param header a reference to the header to remove from the internal buffer.
+   * \param size number of bytes to deserialize
+   * \returns the number of bytes removed from the packet.
+   */
+  uint32_t RemoveHeader (Header &header, uint32_t size);
+  /**
    * \brief Deserialize but does _not_ remove the header from the internal buffer.
    * s
    * This method invokes Header::Deserialize.
@@ -332,6 +345,18 @@
    */
   uint32_t PeekHeader (Header &header) const;
   /**
+   * \brief Deserialize but does _not_ remove the header from the internal buffer.
+   * s
+   * This method invokes Header::Deserialize (begin, end) and should be used
+   * for variable-length headers (where the size is determined somehow
+   * by the caller).
+   *
+   * \param header a reference to the header to read from the internal buffer.
+   * \param size number of bytes to deserialize
+   * \returns the number of bytes read from the packet.
+   */
+  uint32_t PeekHeader (Header &header, uint32_t size) const;
+  /**
    * \brief Add trailer to this packet.
    *
    * This method invokes the
diff -r 34493978d2ae -r 1dd3e78828da src/network/model/trailer.cc
--- a/src/network/model/trailer.cc	Sun May 28 22:22:41 2017 +0200
+++ b/src/network/model/trailer.cc	Tue May 30 07:25:24 2017 -0700
@@ -42,6 +42,14 @@
   return tid;
 }
 
+// This default implementation is provided for backward compatibility
+// reasons.  Subclasses should implement this method themselves.
+uint32_t
+Trailer::Deserialize (Buffer::Iterator start, Buffer::Iterator end)
+{
+  return Deserialize (end);
+}
+
 std::ostream & operator << (std::ostream &os, const Trailer &trailer)
 {
   trailer.Print (os);
diff -r 34493978d2ae -r 1dd3e78828da src/network/model/trailer.h
--- a/src/network/model/trailer.h	Sun May 28 22:22:41 2017 +0200
+++ b/src/network/model/trailer.h	Tue May 30 07:25:24 2017 -0700
@@ -79,10 +79,28 @@
    * representation of this trailer in real networks.
    * The input iterator points to the end of the area where the 
    * data shall be written. This method is thus expected to call
-   * Buffer::Iterator::Prev prio to actually reading any data.
+   * Buffer::Iterator::Prev prior to actually reading any data.
    */
   virtual uint32_t Deserialize (Buffer::Iterator end) = 0;
   /**
+   * \param start an iterator which points to the start of the buffer
+   *        where the trailer should be read from.
+   * \param end an iterator which points to the end of the buffer
+   *        where the trailer should be read from.
+   * \returns the number of bytes read.
+   *
+   * This method is used by Packet::RemoveTrailer to
+   * re-create a trailer from the byte buffer of a packet. 
+   * The data read is expected to match bit-for-bit the 
+   * representation of this trailer in real networks.
+   * The input iterator end points to the end of the area where the 
+   * data shall be written. 
+   *
+   * This variant should be provided by any variable-sized trailer subclass
+   * (i.e. if GetSerializedSize () does not return a constant). 
+   */
+  virtual uint32_t Deserialize (Buffer::Iterator start, Buffer::Iterator end);
+  /**
    * \param os output stream
    * This method is used by Packet::Print to print the 
    * content of a trailer as ascii data to a c++ output stream.