From bf9893dbf309cd5cf1c2102f45565fc0b17c2815 Mon Sep 17 00:00:00 2001
From: Tom Henderson <tomh@tomh.org>
Date: Wed, 10 Sep 2014 16:58:31 -0700
Subject: [PATCH] add processing for unknown TCP options

---
 src/internet/model/tcp-header.cc | 41 ++++++++++++++++++--------------
 src/internet/model/tcp-option.cc |  4 +++-
 src/internet/model/tcp-option.h  |  3 ++-
 3 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/src/internet/model/tcp-header.cc b/src/internet/model/tcp-header.cc
index 2c70b82ca..3ddaee5ea 100644
--- a/src/internet/model/tcp-header.cc
+++ b/src/internet/model/tcp-header.cc
@@ -22,6 +22,7 @@
 #include <iostream>
 #include "tcp-header.h"
 #include "tcp-option.h"
+#include "tcp-option-rfc793.h"
 #include "ns3/buffer.h"
 #include "ns3/address-utils.h"
 #include "ns3/log.h"
@@ -367,30 +368,34 @@ TcpHeader::Deserialize (Buffer::Iterator start)
   // Deserialize options if they exist
   m_options.clear ();
   uint32_t optionLen = (m_length - 5) * 4;
+  NS_ASSERT_MSG (optionLen <= 40, "Illegal TCP option length");
   while (optionLen)
     {
       uint8_t kind = i.PeekU8 ();
-      Ptr<TcpOption> op = TcpOption::CreateOption (kind);
-
+      Ptr<TcpOption> op;
       uint32_t optionSize;
-      optionSize = op->Deserialize (i);
-
-      NS_ASSERT_MSG (optionSize, "Unable to Deserialize an Option of Kind " << int (kind) << ", sorry.");
-      optionLen -= optionSize;
-      i.Next (optionSize);
-
-      if (op->GetKind () != TcpOption::END)
+      if (TcpOption::IsKindKnown (kind))
         {
-          if (TcpOption::IsKindKnown (op->GetKind ()))
-            {
-              m_options.push_back (op);
-            }
-          else
-            {
-              NS_LOG_WARN ("Ignored option kind=" << op->GetKind ());
-            }
+          op = TcpOption::CreateOption (kind);
+        }
+      else 
+        {
+          op = TcpOption::CreateOption (TcpOption::UNKNOWN);
+          NS_LOG_WARN ("Option kind " << static_cast<int> (kind) << " unknown, skipping.");
+        }
+      optionSize = op->Deserialize (i);
+      NS_ASSERT_MSG (optionSize == op->GetSerializedSize (), "Option did not deserialize correctly");
+      if (optionLen >= optionSize)
+        {
+          optionLen -= optionSize;
+          i.Next (optionSize);
+          m_options.push_back (op);
         }
       else
+        {
+          NS_ASSERT_MSG (false, "Option exceeds TCP option space");
+        }
+      if (op->GetKind () == TcpOption::END)
         {
           while (optionLen)
             {
@@ -438,7 +443,7 @@ TcpHeader::AppendOption (Ptr<TcpOption> option)
     {
       if (!TcpOption::IsKindKnown (option->GetKind ()))
         {
-          NS_LOG_WARN ("The option kind " << option->GetKind () << " is unknown");
+          NS_LOG_WARN ("The option kind " << static_cast<int> (option->GetKind ()) << " is unknown");
           return false;
         }
 
diff --git a/src/internet/model/tcp-option.cc b/src/internet/model/tcp-option.cc
index 341ac8fbb..01c8e51ae 100644
--- a/src/internet/model/tcp-option.cc
+++ b/src/internet/model/tcp-option.cc
@@ -71,7 +71,8 @@ TcpOption::CreateOption (uint8_t kind)
     { TcpOption::MSS,       TcpOptionMSS::GetTypeId () },
     { TcpOption::NOP,       TcpOptionNOP::GetTypeId () },
     { TcpOption::TS,        TcpOptionTS::GetTypeId () },
-    { TcpOption::WINSCALE,  TcpOptionWinScale::GetTypeId () }
+    { TcpOption::WINSCALE,  TcpOptionWinScale::GetTypeId () },
+    { TcpOption::UNKNOWN,  TcpOptionUnknown::GetTypeId () }
   };
 
   for (unsigned int i = 0; i < sizeof (toTid) / sizeof (kindToTid); ++i)
@@ -96,6 +97,7 @@ TcpOption::IsKindKnown (uint8_t kind)
     case MSS:
     case WINSCALE:
     case TS:
+    // Do not add UNKNOWN here
       return true;
     }
 
diff --git a/src/internet/model/tcp-option.h b/src/internet/model/tcp-option.h
index 90eff1ff3..461e23d5f 100644
--- a/src/internet/model/tcp-option.h
+++ b/src/internet/model/tcp-option.h
@@ -56,7 +56,8 @@ public:
     NOP = 1,      //!< NOP
     MSS = 2,      //!< MSS
     WINSCALE = 3, //!< WINSCALE
-    TS = 8        //!< TS
+    TS = 8,       //!< TS
+    UNKNOWN = 255 //!< not a standardized value; for unknown recv'd options
   };
 
   /**