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+/*
+ * Copyright (c) 2021 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.
+ */
+
+/**
+ * \file strategy.h
+ * \brief hICN forwarding strategy
+ */
+#ifndef HICNLIGHT_STRATEGY_H
+#define HICNLIGHT_STRATEGY_H
+
+/*
+ * Forwarding strategy
+ *
+ * The forwarding strategy decides to elect one or several next hops among those
+ * available in the FIB entry, after an eventual application of the policy. This
+ * means it should be aware of the different flags set in the nexthops_t data
+ * structure by previous forwarding steps, that might have excluded certain
+ * nexthops.
+ *
+ * A strategy is defined by its type and comes with :
+ *  - options, initialized at setup and that might eventually be updated (this
+ *  is allowed on a per-strategy basis.
+ *  - a state (eventually) empty, that is used to inform its decisions, and
+ *  might be updated for each interest sent (lookup_nexthops), data received
+ *  (on_data) or timeout event (on_timeout).
+ *
+ * All this information (type, options, state) is made available through a
+ * strategy_entry_t which is stored together with nexthops in the FIB entry.
+ *
+ * Per-nexthop strategy informaton is stored in the nexthops table itself. As it
+ * would be difficult and suboptimal to provide a correct strategy-dependent
+ * initialization in the FIB nad nexthops data structures, it is thus the
+ * responsibility of the forwarding strategy to initialize its state and nexthop
+ * related state when appropriate (eg. at initialization, or when a nexthop is
+ * added).
+ */
+
+#include "nexthops.h"
+#include "strategy_vft.h"
+
+typedef struct strategy_entry_s {
+  const void *forwarder;
+  strategy_type_t type;
+  strategy_options_t options;
+  strategy_state_t state;
+} strategy_entry_t;
+
+int strategy_initialize(strategy_entry_t *entry, const void *forwarder);
+
+int strategy_finalize(strategy_entry_t *entry);
+
+nexthops_t *strategy_lookup_nexthops(strategy_entry_t *entry,
+                                     nexthops_t *nexthops,
+                                     const msgbuf_t *msgbuf);
+
+int strategy_add_nexthop(strategy_entry_t *entry, nexthops_t *nexthops,
+                         off_t offset);
+
+int strategy_remove_nexthop(strategy_entry_t *entry, nexthops_t *nexthops,
+                            off_t offset);
+
+int strategy_on_data(strategy_entry_t *entry, nexthops_t *nexthops,
+                     const nexthops_t *data_nexthops, const msgbuf_t *msgbuf,
+                     Ticks pitEntryCreation, Ticks objReception);
+
+int strategy_on_timeout(strategy_entry_t *entry, nexthops_t *nexthops,
+                        const nexthops_t *timeout_nexthops);
+
+#endif /* HICNLIGHT_STRATEGY_H */