From 96774d6d67e4fb69a63535f6901e7de77079bf4a Mon Sep 17 00:00:00 2001
From: Rediet <getachew.redieteab@orange.com>
Date: Mon, 1 Apr 2019 11:10:25 +0200
Subject: [PATCH] wifi: Add a method to check whether packet is an A-MPDU

---
 src/wifi/model/wifi-utils.cc | 38 ++++++++++++++++++++++++++++++++++++
 src/wifi/model/wifi-utils.h  |  7 +++++++
 2 files changed, 45 insertions(+)

diff --git a/src/wifi/model/wifi-utils.cc b/src/wifi/model/wifi-utils.cc
index 321e771f5..02d8a60f2 100644
--- a/src/wifi/model/wifi-utils.cc
+++ b/src/wifi/model/wifi-utils.cc
@@ -27,6 +27,7 @@
 #include "ht-configuration.h"
 #include "he-configuration.h"
 #include "wifi-mode.h"
+#include "ampdu-subframe-header.h"
 
 namespace ns3 {
 
@@ -264,4 +265,41 @@ GetPpduMaxTime (WifiPreamble preamble)
   return duration;
 }
 
+bool
+IsAmpdu (Ptr<const Packet> packet)
+{
+  AmpduSubframeHeader hdr;
+  //Rely on metadata if present
+  bool metadataEnabled = false;
+  PacketMetadata::ItemIterator metadataIterator = packet->BeginItem ();
+  while (metadataIterator.HasNext ())
+    {
+      metadataEnabled = true;
+      PacketMetadata::Item item = metadataIterator.Next ();
+      if (item.tid == hdr.GetTypeId ())
+        {
+          return true;
+        }
+    }
+  if (metadataEnabled)
+    {
+      //Didn't find header in metadata
+      return false;
+    }
+
+  //No metadata so peek manually into buffer and check consistency of extracted data
+  uint32_t totalSize = packet->GetSize ();
+  uint32_t deserialized = packet->PeekHeader (hdr);
+  if (deserialized == hdr.GetSerializedSize ()
+      && hdr.IsSignatureValid ()
+      && hdr.GetLength () <= (totalSize - deserialized))
+    {
+      return true;
+    }
+  else
+    {
+      return false;
+    }
+}
+
 } //namespace ns3
diff --git a/src/wifi/model/wifi-utils.h b/src/wifi/model/wifi-utils.h
index 168fffd4d..a9ff9d911 100644
--- a/src/wifi/model/wifi-utils.h
+++ b/src/wifi/model/wifi-utils.h
@@ -175,6 +175,13 @@ void AddWifiMacTrailer (Ptr<Packet> packet);
  * \return the total packet size
  */
 uint32_t GetSize (Ptr<const Packet> packet, const WifiMacHeader *hdr, bool isAmpdu);
+/**
+ * \param packet the packet to check
+ * \returns true if packet is an A-MPDU
+ *
+ * This method checks if the packet is an A-MPDU by looking for A-MPDU subframe headers.
+ */
+bool IsAmpdu (Ptr<const Packet> packet);
 
   /**
    * Get the maximum PPDU duration (see Section 10.14 of 802.11-2016) for