/src/ntopng/include/GenericHash.h

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/*
 *
 * (C) 2013-24 - ntop.org
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 */

#ifndef _GENERIC_HASH_H_
#define _GENERIC_HASH_H_

#include "ntop_includes.h"

class GenericHashEntry;

/** @defgroup MonitoringData Monitoring Data
 * This is the group that contains all classes and datastructures that handle
 * monitoring data.
 */

/** @class GenericHash
 *  @brief Base hash class.
 *  @details Defined the base hash class for ntopng.
 *
 *  @ingroup MonitoringData
 *
 */
class GenericHash {
 protected:
  GenericHashEntry *
      *table; /**< Entry table. It is used for maintain an update history */
  char *name;
  u_int32_t num_hashes;    /**< Number of hash */
  u_int32_t current_size;  /**< Current size of hash (including idle or
                              ready-to-purge elements) */
  u_int32_t max_hash_size; /**< Max size of hash */
  u_int32_t
      upper_num_visited_entries; /**< Max number of entries to purge per run */
  u_int32_t hash_mask;
  RwLock **locks;
  NetworkInterface
      *iface; /**< Pointer of network interface for this generic hash */
  u_int32_t last_purged_hash; /**< Index of last purged hash */
  u_int32_t last_entry_id;    /**< An uniue identifier assigned to each entry in
                                 the hash table */
  u_int purge_step;
  u_int walk_idle_start_hash_id; /**< The id of the hash bucket from which to
                                    start walkIdle hash table walk */
  struct {
    u_int64_t num_idle_transitions;
    u_int64_t num_purged;
  } entry_state_transition_counters;

  vector<GenericHashEntry *>
      *idle_entries_in_use; /**< Vector used by the offline thread in charge to
                               hold idle entries but still in use */
  vector<GenericHashEntry *>
      *idle_entries; /**< Vector used by the offline thread in charge of
                        deleting hash table entries */
  vector<GenericHashEntry *>
      *idle_entries_shadow; /**< Vector prepared by the purgeIdle and
                               periodically swapped to idle_entries */

 public:
  /**
   * @brief A Constructor
   * @details Creating a new GenericHash.
   *
   * @param _iface Network interface pointer for the new hash.
   * @param _num_hashes Number of hashes.
   * @param _max_hash_size Max size of new hash.
   * @param _name Hash name (debug)
   * @return A new Instance of GenericHash.
   */
  GenericHash(NetworkInterface *_iface, u_int _num_hashes, u_int _max_hash_size,
              const char *_name);

  /**
   * @brief A Destructor
   */
  virtual ~GenericHash();

  /**
   * @brief Get number of entries.
   * @details Inline method.
   *
   * @return Current size of hash.
   */
  inline u_int32_t getNumEntries() { return (current_size); };

  /**
   * @brief Get number of idle entries, that is, entries no longer in the hash
   * table but still to be purged.
   * @details Inline method.
   *
   * @return The number of idle entries.
   */
  u_int32_t getNumIdleEntries() const;

  /**
   * @brief Add new entry to generic hash.
   * @details If current_size < max_hash_size, this method calculate a new hash
   * key for the new entry, add it and update the current_size value.
   *
   * @param h Pointer of new entry to add.
   * @param h whether the bucket should be locked before addin the entry to the
   * linked list.
   * @return True if the entry has been added successfully,
   *         False otherwise.
   *
   */
  bool add(GenericHashEntry *h, bool do_lock);

  /**
   * @brief Generic hash table walker
   * @details This method traverses all the non-idle entries of the hash table,
   * calling the walker function on each of them. Function idle() is called for
   * each entry to evaluate its state, determine if the entry is idle, and
   * possibly call the walker.
   *
   * @param begin_slot begin hash slot. Use 0 to walk all slots
   * @param walk_all true = walk all hash, false, walk only one (non NULL) slot
   * @param walker A pointer to the comparison function.
   * @param user_data Value to be compared with the values of hash.
   */
  bool walk(u_int32_t *begin_slot, bool walk_all,
            bool (*walker)(GenericHashEntry *h, void *user_data,
                           bool *entryMatched),
            void *user_data);

  /**
   * @brief Purge idle entries that have been previous idled by purgeIdle() via
   * periodic calls
   * @return The number of purged entries
   */
  u_int64_t purgeQueuedIdleEntries();

  /**
   * @brief Purge idle hash entries.
   *
   * @param tv Timestamp of the current purge
   * @param force_idle Forcefully marks all hash_entry_state_active entries to
   * hash_entry_state_idle
   * @param full_scan Force a full scan to purge all idle entries in one shot
   *
   * @return Numbers of purged entry, 0 otherwise.
   */
  u_int purgeIdle(const struct timeval *tv, bool force_idle, bool full_scan);

  /**
   * @brief Purge all hash entries.
   *
   */
  void cleanup();

  /**
   * @brief Return the network interface instance associated with the hash.
   * @details Inline method.
   *
   * @return Pointer of network interface instance.
   */
  inline NetworkInterface *getInterface() { return (iface); };

  /**
   * @brief Return the name associated with the hash.
   * @details Inline method.
   *
   * @return Pointer to the name
   */
  inline const char *getName() const { return name; };

  /**
   * @brief Check whether the hash has empty space
   *
   * @return true if there is space left, or false if the hash is full
   */
  bool hasEmptyRoom();

  /**
   * @brief Populates a lua table with hash table stats, including
   * the state transitions
   *
   * @param vm A lua VM
   *
   * @return Current size of hash.
   */
  void lua(lua_State *vm);
};

#endif /* _GENERIC_HASH_H_ */

Coverage Report

Created: 2024-02-25 06:37

Line	Count	Source (jump to first uncovered line)
1		/*
2		*
3		* (C) 2013-24 - ntop.org
4		*
5		*
6		* This program is free software; you can redistribute it and/or modify
7		* it under the terms of the GNU General Public License as published by
8		* the Free Software Foundation; either version 3 of the License, or
9		* (at your option) any later version.
10		*
11		* This program is distributed in the hope that it will be useful,
12		* but WITHOUT ANY WARRANTY; without even the implied warranty of
13		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14		* GNU General Public License for more details.
15		*
16		* You should have received a copy of the GNU General Public License
17		* along with this program; if not, write to the Free Software Foundation,
18		* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19		*
20		*/
21
22		#ifndef _GENERIC_HASH_H_
23		#define _GENERIC_HASH_H_
24
25		#include "ntop_includes.h"
26
27		class GenericHashEntry;
28
29		/** @defgroup MonitoringData Monitoring Data
30		* This is the group that contains all classes and datastructures that handle
31		* monitoring data.
32		*/
33
34		/** @class GenericHash
35		* @brief Base hash class.
36		* @details Defined the base hash class for ntopng.
37		*
38		* @ingroup MonitoringData
39		*
40		*/
41		class GenericHash {
42		protected:
43		GenericHashEntry *
44		table; /< Entry table. It is used for maintain an update history /
45		char *name;
46		u_int32_t num_hashes; /*< Number of hash /
47		u_int32_t current_size; /**< Current size of hash (including idle or
48		ready-to-purge elements) */
49		u_int32_t max_hash_size; /*< Max size of hash /
50		u_int32_t
51		upper_num_visited_entries; /*< Max number of entries to purge per run /
52		u_int32_t hash_mask;
53		RwLock **locks;
54		NetworkInterface
55		iface; /< Pointer of network interface for this generic hash /
56		u_int32_t last_purged_hash; /*< Index of last purged hash /
57		u_int32_t last_entry_id; /**< An uniue identifier assigned to each entry in
58		the hash table */
59		u_int purge_step;
60		u_int walk_idle_start_hash_id; /**< The id of the hash bucket from which to
61		start walkIdle hash table walk */
62		struct {
63		u_int64_t num_idle_transitions;
64		u_int64_t num_purged;
65		} entry_state_transition_counters;
66
67		vector<GenericHashEntry *>
68		idle_entries_in_use; /*< Vector used by the offline thread in charge to
69		hold idle entries but still in use */
70		vector<GenericHashEntry *>
71		idle_entries; /*< Vector used by the offline thread in charge of
72		deleting hash table entries */
73		vector<GenericHashEntry *>
74		idle_entries_shadow; /*< Vector prepared by the purgeIdle and
75		periodically swapped to idle_entries */
76
77		public:
78		/**
79		* @brief A Constructor
80		* @details Creating a new GenericHash.
81		*
82		* @param _iface Network interface pointer for the new hash.
83		* @param _num_hashes Number of hashes.
84		* @param _max_hash_size Max size of new hash.
85		* @param _name Hash name (debug)
86		* @return A new Instance of GenericHash.
87		*/
88		GenericHash(NetworkInterface *_iface, u_int _num_hashes, u_int _max_hash_size,
89		const char *_name);
90
91		/**
92		* @brief A Destructor
93		*/
94		virtual ~GenericHash();
95
96		/**
97		* @brief Get number of entries.
98		* @details Inline method.
99		*
100		* @return Current size of hash.
101		*/
102	188k	inline u_int32_t getNumEntries() { return (current_size); };
103
104		/**
105		* @brief Get number of idle entries, that is, entries no longer in the hash
106		* table but still to be purged.
107		* @details Inline method.
108		*
109		* @return The number of idle entries.
110		*/
111		u_int32_t getNumIdleEntries() const;
112
113		/**
114		* @brief Add new entry to generic hash.
115		* @details If current_size < max_hash_size, this method calculate a new hash
116		* key for the new entry, add it and update the current_size value.
117		*
118		* @param h Pointer of new entry to add.
119		* @param h whether the bucket should be locked before addin the entry to the
120		* linked list.
121		* @return True if the entry has been added successfully,
122		* False otherwise.
123		*
124		*/
125		bool add(GenericHashEntry *h, bool do_lock);
126
127		/**
128		* @brief Generic hash table walker
129		* @details This method traverses all the non-idle entries of the hash table,
130		* calling the walker function on each of them. Function idle() is called for
131		* each entry to evaluate its state, determine if the entry is idle, and
132		* possibly call the walker.
133		*
134		* @param begin_slot begin hash slot. Use 0 to walk all slots
135		* @param walk_all true = walk all hash, false, walk only one (non NULL) slot
136		* @param walker A pointer to the comparison function.
137		* @param user_data Value to be compared with the values of hash.
138		*/
139		bool walk(u_int32_t *begin_slot, bool walk_all,
140		bool (walker)(GenericHashEntry h, void *user_data,
141		bool *entryMatched),
142		void *user_data);
143
144		/**
145		* @brief Purge idle entries that have been previous idled by purgeIdle() via
146		* periodic calls
147		* @return The number of purged entries
148		*/
149		u_int64_t purgeQueuedIdleEntries();
150
151		/**
152		* @brief Purge idle hash entries.
153		*
154		* @param tv Timestamp of the current purge
155		* @param force_idle Forcefully marks all hash_entry_state_active entries to
156		* hash_entry_state_idle
157		* @param full_scan Force a full scan to purge all idle entries in one shot
158		*
159		* @return Numbers of purged entry, 0 otherwise.
160		*/
161		u_int purgeIdle(const struct timeval *tv, bool force_idle, bool full_scan);
162
163		/**
164		* @brief Purge all hash entries.
165		*
166		*/
167		void cleanup();
168
169		/**
170		* @brief Return the network interface instance associated with the hash.
171		* @details Inline method.
172		*
173		* @return Pointer of network interface instance.
174		*/
175	0	inline NetworkInterface *getInterface() { return (iface); };
176
177		/**
178		* @brief Return the name associated with the hash.
179		* @details Inline method.
180		*
181		* @return Pointer to the name
182		*/
183	0	inline const char *getName() const { return name; };
184
185		/**
186		* @brief Check whether the hash has empty space
187		*
188		* @return true if there is space left, or false if the hash is full
189		*/
190		bool hasEmptyRoom();
191
192		/**
193		* @brief Populates a lua table with hash table stats, including
194		* the state transitions
195		*
196		* @param vm A lua VM
197		*
198		* @return Current size of hash.
199		*/
200		void lua(lua_State *vm);
201		};
202
203		#endif /* _GENERIC_HASH_H_ */