docs: wrote Doxygen comments for all files

refs: #4118

Change-Id: Ib0e7f1926cdabcca5aa401b59b24519412a099f7
diff --git a/src/route/fib.hpp b/src/route/fib.hpp
index 4f15655..5761a3d 100644
--- a/src/route/fib.hpp
+++ b/src/route/fib.hpp
@@ -38,6 +38,19 @@
 class ConfParameter;
 class FibEntry;
 
+/*! \brief Maps names to lists of next hops, and exports this information to NFD.
+ *
+ * The FIB (Forwarding Information Base) is the "authoritative" source
+ * of how to route Interests on this router to other nodes running
+ * NLSR. In essence, the FIB is a map that takes name prefixes to a
+ * list of next-hops out of this router. This class also contains
+ * methods to inform NFD about these relationships. The FIB has its
+ * entries populated by the NamePrefixTable
+ *
+ * \sa nlsr::NamePrefixTable
+ * \sa nlsr::NamePrefixTable::addEntry
+ * \sa nlsr::NamePrefixTable::updateWithNewRoute
+ */
 class Fib
 {
 public:
@@ -51,15 +64,42 @@
   {
   }
 
-  FibEntry*
-  processUpdate(const ndn::Name& name, NexthopList& allHops);
-
+  /*! \brief Completely remove a name prefix from the FIB.
+   *
+   * If a name prefix is found to no longer be reachable from this
+   * router, it will be removed from the FIB and all of its next-hops
+   * will be unregistered from NFD.
+   *
+   * \sa nlsr::NamePrefixTable::removeEntry
+   */
   VIRTUAL_WITH_TESTS void
   remove(const ndn::Name& name);
 
+  /*! \brief Set the nexthop list of a name.
+   *
+   * This method is the entry for others to add next-hop information
+   * to the FIB. Formally put, this method registers in NFD all
+   * next-hops in allHops, and unregisters the set difference of
+   * newHops - oldHops. This method also schedules the regular refresh
+   * of those next hops.
+   *
+   * \param name The name prefix that the next-hops apply to
+   * \param allHops A complete list of next-hops to associate with name.
+   */
   VIRTUAL_WITH_TESTS void
   update(const ndn::Name& name, NexthopList& allHops);
 
+  /*! \brief Remove all entries from the FIB.
+   *
+   * This method is called before terminating NLSR to minimize the
+   * time NFD spends routing on now-invalid information. This is not
+   * strictly necessary, because eventually those prefix registrations
+   * will expire, but cleaning up after ourselves improves
+   * performance.
+   *
+   * \sa NlsrRunner::run
+   *
+   */
   void
   clean();
 
@@ -69,6 +109,26 @@
     m_refreshTime = fert;
   }
 
+  /*! \brief Inform NFD of a next-hop
+   *
+   * This method informs NFD of a next-hop for some name prefix. This
+   * method actually submits the information to NFD's RIB, which then
+   * aggregates its own best hops and updates NFD's (the actual)
+   * FIB. Typically, NLSR's FIB and NFD's FIB will be almost the
+   * same. However, this is not necessarily the case and there may be
+   * cases when other sources of information provide better next-hops
+   * to NFD that NLSR doesn't know about. For example, an operator
+   * could set up a direct link to a node that isn't running NLSR.
+   *
+   * \param namePrefix The name prefix to register a next-hop for
+   * \param faceUri The faceUri of the adjacent that this prefix can be reached through
+   * \param faceCost The cost to reach namePrefix through faceUri
+   * \param timeout How long this registration should last
+   * \param flags Route inheritance flags (CAPTURE, CHILD_INHERIT)
+   * \param times How many times we have failed to register this prefix since the last success.
+   *
+   * \sa Fib::registerPrefixInNfd
+   */
   void
   registerPrefix(const ndn::Name& namePrefix,
                  const ndn::util::FaceUri& faceUri,
@@ -84,22 +144,39 @@
   writeLog();
 
 private:
+  /*! \brief Indicates whether a prefix is a direct neighbor or not.
+   *
+   * \return Whether the name is NOT associated with a direct neighbor
+   */
   bool
   isPrefixUpdatable(const ndn::Name& name);
 
+  /*! \brief Does one half of the updating of a FibEntry with new next-hops.
+   *
+   * Adds nexthops to a FibEntry and registers them in NFD.
+   * \sa Fib::update
+   * \sa Fib::removeOldNextHopsFromFibEntryAndNfd
+   */
   void
   addNextHopsToFibEntryAndNfd(FibEntry& entry, NexthopList& hopsToAdd);
 
   unsigned int
   getNumberOfFacesForName(NexthopList& nextHopList);
 
+  /*! \brief Unregisters a prefix from NFD's RIB.
+   *
+   */
   void
   unregisterPrefix(const ndn::Name& namePrefix, const std::string& faceUri);
 
+  /*! \brief Log registration success, and update the Face ID associated with a URI.
+   */
   void
   onRegistrationSuccess(const ndn::nfd::ControlParameters& commandSuccessResult,
                         const std::string& message, const ndn::util::FaceUri& faceUri);
 
+  /*! \brief Retry a prefix (next-hop) registration up to three (3) times.
+   */
   void
   onRegistrationFailure(const ndn::nfd::ControlResponse& response,
                         const std::string& message,
@@ -107,18 +184,26 @@
                         const ndn::util::FaceUri& faceUri,
                         uint8_t times);
 
+  /*! \brief Log a successful unregistration.
+   */
   void
   onUnregistrationSuccess(const ndn::nfd::ControlParameters& commandSuccessResult,
                           const std::string& message);
 
+  /*! \brief Log an unregistration failure. Does not retry.
+   */
   void
   onUnregistrationFailure(const ndn::nfd::ControlResponse& response,
                                const std::string& message);
 
+  /*! \brief Log a successful strategy setting.
+   */
   void
   onSetStrategySuccess(const ndn::nfd::ControlParameters& commandSuccessResult,
                        const std::string& message);
 
+  /*! \brief Retry a strategy setting up to three (3) times.
+   */
   void
   onSetStrategyFailure(const ndn::nfd::ControlResponse& response,
                        const ndn::nfd::ControlParameters& parameters,
@@ -126,16 +211,45 @@
                        const std::string& message);
 
 PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  /*! \brief Internal portion of Fib::update.
+   * \sa Fib::update
+   */
+  FibEntry*
+  processUpdate(const ndn::Name& name, NexthopList& allHops);
+
+  /*! \brief Schedule a refresh event for an entry.
+   *
+   * Schedules a refresh event for an entry. In order to form a
+   * perpetual loop, refreshCallback needs to call
+   * Fib::scheduleEntryRefresh in some way, with refreshCallback being
+   * the same each time. In the current implementation, this is
+   * accomplished by having a separate function, Fib::scheduleLoop,
+   * that does this work.
+   * \sa Fib::scheduleLoop
+   */
   void
   scheduleEntryRefresh(FibEntry& entry, const afterRefreshCallback& refreshCb);
 
 private:
+  /*! \brief Continue the entry refresh cycle.
+   */
   void
   scheduleLoop(FibEntry& entry);
 
+  /*! \brief Cancel an entry's refresh event.
+   *
+   * Cancel an entry's refresh event. This only needs to be done when
+   * an entry is removed. Typically this happens when NLSR is
+   * terminated or crashes, and we don't want the scheduler to crash
+   * because it's referencing memory that has no valid function.
+   *
+   * \sa NlsrRunner::run
+   */
   void
   cancelEntryRefresh(const FibEntry& entry);
 
+  /*! \brief Refreshes an entry in NFD.
+   */
   void
   refreshEntry(const ndn::Name& name, afterRefreshCallback refreshCb);
 
@@ -152,6 +266,10 @@
   AdjacencyList& m_adjacencyList;
   ConfParameter& m_confParameter;
 
+  /*! GRACE_PERIOD A "window" we append to the timeout time to
+   * allow for things like stuttering prefix registrations and
+   * processing time when refreshing events.
+   */
   static const uint64_t GRACE_PERIOD;
 };