From 7870451290d356784093fbff3c734dffa6d53b41 Mon Sep 17 00:00:00 2001
From: Tommaso Pecorella <tommaso.pecorella@unifi.it>
Date: Sat, 19 Sep 2015 16:14:49 +0200
Subject: [PATCH] Bug 2177 - Ipv6ExtensionHeader length - code cleanup and
 remove hardcoded values

---
 src/applications/model/ping6.cc             |  1 -
 src/internet/model/ipv6-extension-header.cc | 30 ++++++++++++---------
 src/internet/model/ipv6-extension-header.h  | 11 ++++----
 src/internet/model/ipv6-extension.cc        |  1 -
 4 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/src/applications/model/ping6.cc b/src/applications/model/ping6.cc
index ac2707fc3..21a30237a 100644
--- a/src/applications/model/ping6.cc
+++ b/src/applications/model/ping6.cc
@@ -214,7 +214,6 @@ void Ping6::Send ()
     {
       Ipv6ExtensionLooseRoutingHeader routingHeader;
       routingHeader.SetNextHeader (Ipv6Header::IPV6_ICMPV6);
-      routingHeader.SetLength (m_routers.size () * 16 + 8);
       routingHeader.SetTypeRouting (0);
       routingHeader.SetSegmentsLeft (m_routers.size ());
       routingHeader.SetRoutersAddress (m_routers);
diff --git a/src/internet/model/ipv6-extension-header.cc b/src/internet/model/ipv6-extension-header.cc
index 273a04867..1eb0c7e71 100644
--- a/src/internet/model/ipv6-extension-header.cc
+++ b/src/internet/model/ipv6-extension-header.cc
@@ -46,8 +46,8 @@ TypeId Ipv6ExtensionHeader::GetInstanceTypeId () const
 }
 
 Ipv6ExtensionHeader::Ipv6ExtensionHeader ()
-  : m_nextHeader (0),
-    m_length (0),
+  : m_length (0),
+    m_nextHeader (0),
     m_data (0)
 {
 }
@@ -254,7 +254,7 @@ uint32_t Ipv6ExtensionHopByHopHeader::Deserialize (Buffer::Iterator start)
   Buffer::Iterator i = start;
 
   SetNextHeader (i.ReadU8 ());
-  SetLength ((i.ReadU8 () + 1) << 3);
+  m_length = i.ReadU8 ();
   OptionField::Deserialize (i, GetLength () - 2);
 
   return GetSerializedSize ();
@@ -310,7 +310,7 @@ uint32_t Ipv6ExtensionDestinationHeader::Deserialize (Buffer::Iterator start)
   Buffer::Iterator i = start;
 
   SetNextHeader (i.ReadU8 ());
-  SetLength ((i.ReadU8 () + 1) << 3);
+  m_length = i.ReadU8 ();
   OptionField::Deserialize (i, GetLength () - 2);
 
   return GetSerializedSize ();
@@ -337,7 +337,7 @@ Ipv6ExtensionFragmentHeader::Ipv6ExtensionFragmentHeader ()
   : m_offset (0),
     m_identification (0)
 {
-  SetLength (16);
+  m_length = 0;
 }
 
 Ipv6ExtensionFragmentHeader::~Ipv6ExtensionFragmentHeader ()
@@ -392,6 +392,7 @@ void Ipv6ExtensionFragmentHeader::Serialize (Buffer::Iterator start) const
   Buffer::Iterator i = start;
 
   i.WriteU8 (GetNextHeader ());
+  // Fragment header does not carry an extension length
   i.WriteU8 (0);
   i.WriteHtonU16 (m_offset);
   i.WriteHtonU32 (m_identification);
@@ -402,7 +403,8 @@ uint32_t Ipv6ExtensionFragmentHeader::Deserialize (Buffer::Iterator start)
   Buffer::Iterator i = start;
 
   SetNextHeader (i.ReadU8 ());
-  SetLength ((i.ReadU8 () + 1) << 3);
+  // Fragment header does not carry an extension length
+  i.ReadU8 ();
   m_offset = i.ReadNtohU16 ();
   m_identification = i.ReadNtohU32 ();
 
@@ -472,7 +474,7 @@ void Ipv6ExtensionRoutingHeader::Serialize (Buffer::Iterator start) const
   Buffer::Iterator i = start;
 
   i.WriteU8 (GetNextHeader ());
-  i.WriteU8 ((GetLength () >> 3) - 1);
+  i.WriteU8 (m_length);
   i.WriteU8 (m_typeRouting);
   i.WriteU8 (m_segmentsLeft);
 }
@@ -482,7 +484,7 @@ uint32_t Ipv6ExtensionRoutingHeader::Deserialize (Buffer::Iterator start)
   Buffer::Iterator i = start;
 
   SetNextHeader (i.ReadU8 ());
-  SetLength ((i.ReadU8 () + 1) << 3);
+  m_length = i.ReadU8 ();
   m_typeRouting = i.ReadU8 ();
   m_segmentsLeft = i.ReadU8 ();
 
@@ -564,8 +566,10 @@ void Ipv6ExtensionLooseRoutingHeader::Serialize (Buffer::Iterator start) const
   Buffer::Iterator i = start;
   uint8_t buff[16];
 
+  uint8_t addressNum = m_routersAddress.size ();
+
   i.WriteU8 (GetNextHeader ());
-  i.WriteU8 ((GetLength () >> 3) - 1);
+  i.WriteU8 (addressNum*2);
   i.WriteU8 (GetTypeRouting ());
   i.WriteU8 (GetSegmentsLeft ());
   i.WriteU32 (0);
@@ -583,15 +587,17 @@ uint32_t Ipv6ExtensionLooseRoutingHeader::Deserialize (Buffer::Iterator start)
   uint8_t buff[16];
 
   SetNextHeader (i.ReadU8 ());
-  SetLength ((i.ReadU8 () + 1) << 3);
+  m_length = i.ReadU8 ();
   SetTypeRouting (i.ReadU8 ());
   SetSegmentsLeft (i.ReadU8 ());
   i.ReadU32 ();
 
-  for (std::vector<Ipv6Address>::iterator it = m_routersAddress.begin (); it != m_routersAddress.end (); it++)
+  uint8_t addressNum = m_length / 2;
+  SetNumberAddress (addressNum);
+  for (uint8_t index = 0; index < addressNum; index++)
     {
       i.Read (buff, 16);
-      it->Set (buff);
+      SetRouterAddress (index, Ipv6Address (buff));
     }
 
   return GetSerializedSize ();
diff --git a/src/internet/model/ipv6-extension-header.h b/src/internet/model/ipv6-extension-header.h
index f311d99c6..3be3544ef 100644
--- a/src/internet/model/ipv6-extension-header.h
+++ b/src/internet/model/ipv6-extension-header.h
@@ -111,17 +111,18 @@ public:
    */
   virtual uint32_t Deserialize (Buffer::Iterator start);
 
+protected:
+  /**
+   * \brief The "length" field.
+   */
+  uint8_t m_length;
+
 private:
   /**
    * \brief The "next header" field.
    */
   uint8_t m_nextHeader;
 
-  /**
-   * \brief The "length" field.
-   */
-  uint8_t m_length;
-
   /**
    * \brief The data of the extension.
    */
diff --git a/src/internet/model/ipv6-extension.cc b/src/internet/model/ipv6-extension.cc
index a1855371b..e20c986a2 100644
--- a/src/internet/model/ipv6-extension.cc
+++ b/src/internet/model/ipv6-extension.cc
@@ -1020,7 +1020,6 @@ uint8_t Ipv6ExtensionLooseRouting::Process (Ptr<Packet>& packet,
       return routingHeader.GetSerializedSize ();
     }
 
-  routingHeader.SetLength (88);
   ipv6header.SetHopLimit (hopLimit - 1);
   p->AddHeader (routingHeader);