added SpeckMac

[tinyos-2.x.git] / tos / chips / tda5250 / mac / DuplicateP.nc

diff --git a/tos/chips/tda5250/mac/DuplicateP.nc b/tos/chips/tda5250/mac/DuplicateP.nc
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+/* -*- mode:c++; indent-tabs-mode:nil -*- 
+ * Copyright (c) 2007, Technische Universitaet Berlin
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright 
+ *   notice, this list of conditions and the following disclaimer in the 
+ *   documentation and/or other materials provided with the distribution.
+ * - Neither the name of the Technische Universitaet Berlin nor the names 
+ *   of its contributors may be used to endorse or promote products derived
+ *   from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE 
+ * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/**
+ * Helper component for MAC protocols to suppress duplicates
+ * To do: turn it into a generic?
+ * @author: Andreas Koepke (koepke@tkn.tu-berlin.de)
+ */
+
+module DuplicateP {
+  provides {
+      interface Duplicate;
+      interface Init;
+  }
+  uses {
+      interface Timer<TMilli> as Timer;
+  }
+}
+implementation {    
+    known_t knownTable[TABLE_ENTRIES];
+
+    /** helper functions */
+    task void ageMsgsTask() {
+        unsigned i;
+        for(i = 0; i < TABLE_ENTRIES; i++) {
+            atomic {
+                if(knownTable[i].age < MAX_AGE) ++knownTable[i].age;
+            }
+        }
+    }
+    
+    unsigned findOldest() {
+        unsigned i;
+        unsigned oldIndex = 0;
+        unsigned age = knownTable[oldIndex].age;
+        for(i = 1; i < TABLE_ENTRIES; i++) {
+            if(age < knownTable[i].age) {
+                oldIndex = i;
+                age = knownTable[i].age;
+            }
+        }
+        return oldIndex;
+    }
+
+    /*** duplicate interface */
+    async command bool Duplicate.isNew(am_addr_t src, uint8_t seqno) {
+        bool rVal = TRUE;
+        unsigned i;
+        for(i=0; i < TABLE_ENTRIES; i++) {
+            if((knownTable[i].age < MAX_AGE) &&
+               (src == knownTable[i].src) &&
+               (seqno == knownTable[i].seqno)) {
+                knownTable[i].age = 0;
+                rVal = FALSE;
+                break;
+            }
+        }
+        return rVal;
+    }
+    
+    async command void Duplicate.remember(am_addr_t src, uint8_t seqno) {
+        unsigned oldest = findOldest();
+        knownTable[oldest].src = src;
+        knownTable[oldest].seqno = seqno;
+        knownTable[oldest].age = 0;
+    }
+
+    /** helper interfaces */
+    event void Timer.fired() {
+        post ageMsgsTask();
+    }
+
+    command error_t Init.init(){
+        uint8_t i;
+        for(i = 0; i < TABLE_ENTRIES; i++) {
+            atomic {
+                    knownTable[i].age = MAX_AGE;
+            }
+        }
+        call Timer.startPeriodic(AGE_INTERVALL);
+        return SUCCESS;
+    }
+}
+