Add BlockAckCache class

src/devices/wifi/block-ack-cache.cc

@@ -0,0 +1,134 @@
+/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2010 MIRKO BANCHI
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as 
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Mirko Banchi <mk.banchi@gmail.com>
+ */
+#include "block-ack-cache.h"
+#include "ctrl-headers.h"
+#include "wifi-mac-header.h"
+#include "qos-utils.h"
+
+#define WINSIZE_ASSERT NS_ASSERT ((m_winEnd - m_winStart + 4096) % 4096 == m_winSize - 1)
+
+namespace ns3 {
+
+void
+BlockAckCache::Init (uint16_t winStart, uint16_t winSize)
+{
+  m_winStart = winStart;
+  m_winSize = winSize <= 64 ? winSize : 64;
+  m_winEnd = ((m_winStart + m_winSize) % 4096) - 1;
+  memset (m_bitmap, 0, sizeof (m_bitmap));
+}
+
+void
+BlockAckCache::UpdateWithMpdu (const WifiMacHeader *hdr)
+{
+  uint16_t seqNumber = hdr->GetSequenceNumber ();
+  if (!QosUtilsIsOldPacket (m_winStart, seqNumber))
+    {
+      if (!IsInWindow (seqNumber))
+        {
+          uint16_t delta = (seqNumber - m_winEnd + 4096) % 4096;
+          if (delta > 1)
+            {
+              ResetPortionOfBitmap ((m_winEnd + 1) % 4096, ((seqNumber - 1) + 4096) % 4096);
+            }
+          m_winStart = (m_winStart + delta) % 4096;
+          m_winEnd = seqNumber;
+
+          WINSIZE_ASSERT;
+        }
+      m_bitmap[seqNumber] |= (0x0001<<hdr->GetFragmentNumber ());
+    }
+}
+
+void
+BlockAckCache::UpdateWithBlockAckReq (uint16_t startingSeq)
+{
+  if (!QosUtilsIsOldPacket (m_winStart, startingSeq))
+    {
+      if (IsInWindow (startingSeq))
+        {
+          if (startingSeq != m_winStart)
+            {
+              m_winStart = startingSeq;
+              uint16_t newWinEnd = ((m_winStart + m_winSize) % 4096) - 1;
+              ResetPortionOfBitmap ((m_winEnd + 1) % 4096, newWinEnd);
+              m_winEnd = newWinEnd;
+
+              WINSIZE_ASSERT;
+            }
+        }
+      else
+        {
+          m_winStart = startingSeq;
+          m_winEnd = ((m_winStart + m_winSize) % 4096) - 1;
+          ResetPortionOfBitmap (m_winStart, m_winEnd);
+
+          WINSIZE_ASSERT;
+        }
+    }
+}
+
+void
+BlockAckCache::ResetPortionOfBitmap (uint16_t start, uint16_t end)
+{
+  uint32_t i = start;
+  for (; i != end; i = (i + 1) % 4096)
+    {
+      m_bitmap[i] = 0; 
+    }
+  m_bitmap[i] = 0;
+}
+
+bool
+BlockAckCache::IsInWindow (uint16_t seq)
+{
+  return ((seq - m_winStart + 4096) % 4096) < m_winSize;
+}
+
+void
+BlockAckCache::FillBlockAckBitmap (CtrlBAckResponseHeader *blockAckHeader)
+{
+  if (blockAckHeader->IsBasic ())
+    {
+      NS_FATAL_ERROR ("Basic block ack is only partially implemented.");
+    }
+  else if (blockAckHeader->IsCompressed ())
+    {
+      uint32_t i = blockAckHeader->GetStartingSequence ();
+      uint32_t end = ((i + m_winSize) % 4096) - 1; 
+      for (; i != end; i = (i + 1) % 4096)
+        {
+          if (m_bitmap[i] == 1)
+            {
+              blockAckHeader->SetReceivedPacket (i);
+            }
+        }
+      if (m_bitmap[i] == 1)
+        {
+          blockAckHeader->SetReceivedPacket (i);
+        }
+    }
+  else if (blockAckHeader->IsMultiTid ())
+    {
+      NS_FATAL_ERROR ("Multi-tid block ack is not supported.");
+    }
+}
+
+} //namespace ns3

src/devices/wifi/block-ack-cache.h

@@ -0,0 +1,52 @@
+/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2010 MIRKO BANCHI
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as 
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Mirko Banchi <mk.banchi@gmail.com>
+ */
+#ifndef BLOCK_ACK_CACHE_H
+#define BLOCK_ACK_CACHE_H
+
+#include <stdint.h>
+
+namespace ns3 {
+
+class WifiMacHeader;
+class CtrlBAckResponseHeader;
+
+class BlockAckCache
+{
+public:
+  void Init (uint16_t winStart, uint16_t winSize);
+
+  void UpdateWithMpdu (const WifiMacHeader *hdr);
+  void UpdateWithBlockAckReq (uint16_t startingSeq);
+
+  void FillBlockAckBitmap (CtrlBAckResponseHeader *blockAckHeader);
+private:
+  void ResetPortionOfBitmap (uint16_t start, uint16_t end);
+  bool IsInWindow (uint16_t seq);
+
+  uint16_t m_winStart;
+  uint8_t m_winSize;
+  uint16_t m_winEnd;
+
+  uint16_t m_bitmap[4096];
+};
+
+} //namespace ns3
+
+#endif /* BLOCK_ACK_CACHE_H */

src/devices/wifi/wscript

@@ -65,6 +65,7 @@ def build(bld):
         'block-ack-agreement.cc',
         'block-ack-manager.cc',
         'block-ack-test-suite.cc',
+        'block-ack-cache.cc'
         ]
     headers = bld.new_task_gen('ns3header')
     headers.module = 'wifi'
@@ -123,6 +124,7 @@ def build(bld):
         'ctrl-headers.h',
         'block-ack-agreement.h',
         'block-ack-manager.h',
+        'block-ack-cache.h'
         ]
 
     if bld.env['ENABLE_GSL']: