1 files changed, 226 insertions, 0 deletions
diff --git a/metis/ccnx/forwarder/metis/strategies/strategy_RndSegment.c b/metis/ccnx/forwarder/metis/strategies/strategy_RndSegment.c
new file mode 100644
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+++ b/metis/ccnx/forwarder/metis/strategies/strategy_RndSegment.c
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <config.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <stdlib.h>
+
+#include <LongBow/runtime.h>
+
+#include <parc/algol/parc_Memory.h>
+#include <parc/algol/parc_HashMap.h>
+#include <ccnx/forwarder/metis/tlv/metis_Tlv.h>
+#include <ccnx/forwarder/metis/strategies/strategy_RndSegment.h>
+
+
+static void             _strategyRndSegment_ReceiveObject(MetisStrategyImpl *strategy, const MetisNumberSet *egressId, const MetisMessage *objectMessage, MetisTicks rtt);
+static void             _strategyRndSegment_OnTimeout(MetisStrategyImpl *strategy, const MetisNumberSet *egressId);
+static MetisNumberSet *_strategyRndSegment_LookupNexthop(MetisStrategyImpl *strategy, const MetisMessage *interestMessage);
+static MetisNumberSet *_strategyRndSegment_ReturnNexthops(MetisStrategyImpl *strategy);
+static unsigned         _strategyRndSegment_CountNexthops(MetisStrategyImpl *strategy);
+static void             _strategyRndSegment_AddNexthop(MetisStrategyImpl *strategy, CPIRouteEntry *route);
+static void             _strategyRndSegment_RemoveNexthop(MetisStrategyImpl *strategy, CPIRouteEntry *route);
+static void             _strategyRndSegment_ImplDestroy(MetisStrategyImpl **strategyPtr);
+static const char *_strategyRndSegment_GetStrategy(MetisStrategyImpl *strategy);
+
+static MetisStrategyImpl _template = {
+    .context        = NULL,
+    .receiveObject  = &_strategyRndSegment_ReceiveObject,
+    .onTimeout      = &_strategyRndSegment_OnTimeout,
+    .lookupNexthop  = &_strategyRndSegment_LookupNexthop,
+    .returnNexthops = &_strategyRndSegment_ReturnNexthops,
+    .countNexthops  = &_strategyRndSegment_CountNexthops,
+    .addNexthop     = &_strategyRndSegment_AddNexthop,
+    .removeNexthop  = &_strategyRndSegment_RemoveNexthop,
+    .destroy        = &_strategyRndSegment_ImplDestroy,
+    .getStrategy    = &_strategyRndSegment_GetStrategy,
+};
+
+struct strategy_rnd_segment;
+typedef struct strategy_rnd_segment StrategyRndSegment;
+
+
+struct strategy_rnd_segment {
+    MetisNumberSet *nexthops;
+    MetisTlvName *segmentName;
+    int last_used_face;
+};
+
+MetisStrategyImpl *
+strategyRndSegment_Create()
+{
+    StrategyRndSegment *strategy = parcMemory_AllocateAndClear(sizeof(StrategyRndSegment));
+    assertNotNull(strategy, "parcMemory_AllocateAndClear(%zu) returned NULL", sizeof(StrategyRndSegment));
+
+    strategy->nexthops = metisNumberSet_Create();
+    strategy->segmentName = NULL;
+    strategy->last_used_face = 0;
+    srand(time(NULL));
+
+    MetisStrategyImpl *impl = parcMemory_AllocateAndClear(sizeof(MetisStrategyImpl));
+    assertNotNull(impl, "parcMemory_AllocateAndClear(%zu) returned NULL", sizeof(MetisStrategyImpl));
+    memcpy(impl, &_template, sizeof(MetisStrategyImpl));
+    impl->context = strategy;
+
+    return impl;
+}
+
+// =======================================================
+// Dispatch API
+
+
+static const char*
+_strategyRndSegment_GetStrategy(MetisStrategyImpl *strategy)
+{
+    return FWD_STRATEGY_RANDOM_PER_DASH_SEGMENT;
+}
+
+
+static int
+_select_Nexthop(StrategyRndSegment *strategy)
+{
+    unsigned len = metisNumberSet_Length(strategy->nexthops);
+    if (len == 0) {
+        return -1;
+    }
+
+    int rnd = (rand() % len);
+    return metisNumberSet_GetItem(strategy->nexthops, rnd);
+}
+
+
+static void
+_strategyRndSegment_ReceiveObject(MetisStrategyImpl *strategy, const MetisNumberSet *egressId, const MetisMessage *objectMessage, MetisTicks rtt)
+{
+}
+
+static void
+_strategyRndSegment_OnTimeout(MetisStrategyImpl *strategy, const MetisNumberSet *egressId)
+{
+}
+
+//ATTENTION!! This interface force us to create a MetisNumberSet which need to be delited somewhere (maybe in the FIB where we call this function)
+//The specification in the interface requires that this function never returns NULL. in case we have no output face we need to return an empty MetisNumberSet
+static MetisNumberSet *
+_strategyRndSegment_LookupNexthop(MetisStrategyImpl *strategy, const MetisMessage *interestMessage)
+{
+    StrategyRndSegment *srnd = (StrategyRndSegment *) strategy->context;
+
+
+    unsigned in_connection = metisMessage_GetIngressConnectionId(interestMessage);
+    unsigned nexthopSize = metisNumberSet_Length(srnd->nexthops);
+
+    MetisNumberSet *out = metisNumberSet_Create();
+    if ((nexthopSize == 0) || ((nexthopSize == 1) && metisNumberSet_Contains(srnd->nexthops, in_connection))) {
+        //there are no output faces or the input face is also the only output face. return null to avoid loops
+        return out;
+    }
+
+    if (metisMessage_HasName(interestMessage)) {
+        MetisTlvName *interestName = metisMessage_GetName(interestMessage);
+        size_t sc = metisTlvName_SegmentCount(interestName);
+        interestName = metisTlvName_Slice(interestName, (sc - 1));
+
+        if (srnd->segmentName == NULL) {
+            srnd->segmentName = interestName;
+        } else if (!metisTlvName_Equals(srnd->segmentName, interestName)) {
+            metisTlvName_Release(&srnd->segmentName);
+            srnd->segmentName = interestName;
+        } else  {
+            //here we need to check if the output face still exists or if someone erase it
+            if (metisNumberSet_Contains(srnd->nexthops, srnd->last_used_face)) {
+                // face exists, so keep using it!
+                metisTlvName_Release(&interestName);
+                metisNumberSet_Add(out, srnd->last_used_face);
+                return out;
+            } else  {
+                //the face does not exists anymore, try to find a new face but keep the name
+                //of the dash segment
+                metisTlvName_Release(&interestName);
+            }
+        }
+    }
+
+    int out_connection;
+    do {
+        out_connection = _select_Nexthop(srnd);
+    } while (out_connection == in_connection);
+
+    if (out_connection == -1) {
+        return out;
+    }
+
+    srnd->last_used_face = out_connection;
+    metisNumberSet_Add(out, out_connection);
+    return out;
+}
+
+static MetisNumberSet *
+_strategyRndSegment_ReturnNexthops(MetisStrategyImpl *strategy)
+{
+    StrategyRndSegment *srnd = (StrategyRndSegment *) strategy->context;
+    return srnd->nexthops;
+}
+
+unsigned
+_strategyRndSegment_CountNexthops(MetisStrategyImpl *strategy)
+{
+    StrategyRndSegment *srnd = (StrategyRndSegment *) strategy->context;
+    return metisNumberSet_Length(srnd->nexthops);
+}
+
+static void
+_strategyRndSegment_AddNexthop(MetisStrategyImpl *strategy, CPIRouteEntry *route)
+{
+    unsigned connectionId = cpiRouteEntry_GetInterfaceIndex(route); //this returns what in all the rest of the ccnx code is called connection id!
+
+    StrategyRndSegment *srnd = (StrategyRndSegment *) strategy->context;
+    if (!metisNumberSet_Contains(srnd->nexthops, connectionId)) {
+        metisNumberSet_Add(srnd->nexthops, connectionId);
+    }
+}
+
+static void
+_strategyRndSegment_RemoveNexthop(MetisStrategyImpl *strategy, CPIRouteEntry *route)
+{
+    unsigned connectionId = cpiRouteEntry_GetInterfaceIndex(route);
+    StrategyRndSegment *srnd = (StrategyRndSegment *) strategy->context;
+
+    if (metisNumberSet_Contains(srnd->nexthops, connectionId)) {
+        metisNumberSet_Remove(srnd->nexthops, connectionId);
+    }
+}
+
+static void
+_strategyRndSegment_ImplDestroy(MetisStrategyImpl **strategyPtr)
+{
+    assertNotNull(strategyPtr, "Parameter must be non-null double pointer");
+    assertNotNull(*strategyPtr, "Parameter must dereference to non-null pointer");
+
+    MetisStrategyImpl *impl = *strategyPtr;
+    StrategyRndSegment *strategy = (StrategyRndSegment *) impl->context;
+
+    metisNumberSet_Release(&(strategy->nexthops));
+    if (strategy->segmentName != NULL) {
+        metisTlvName_Release(&strategy->segmentName);
+    }
+
+    parcMemory_Deallocate((void **) &strategy);
+    parcMemory_Deallocate((void **) &impl);
+    *strategyPtr = NULL;
+}