text: /* Copyright (c) 2015-2017, The Tor Project, Inc. */
  /* See LICENSE for licensing information */
  
  /**
   * \file rendcache.h
   * \brief Header file for rendcache.c
   **/
  
  #ifndef TOR_RENDCACHE_H
  #define TOR_RENDCACHE_H
  
  #include "or.h"
  #include "rendcommon.h"
  
  /** How old do we let hidden service descriptors get before discarding
   * them as too old? */
  #define REND_CACHE_MAX_AGE (2*24*60*60)
  /** How wrong do we assume our clock may be when checking whether hidden
   * services are too old or too new? */
  #define REND_CACHE_MAX_SKEW (24*60*60)
  /** How old do we keep an intro point failure entry in the failure cache? */
  #define REND_CACHE_FAILURE_MAX_AGE (5*60)
  
  /* Do not allow more than this many introduction points in a hidden service
   * descriptor */
  #define MAX_INTRO_POINTS 10
  
  /** A cached rendezvous descriptor. */
  typedef struct rend_cache_entry_t {
    size_t len; /**< Length of <b>desc</b> */
    time_t last_served; /**< When did we last write this one to somebody?
                         * (HSDir only) */
    char *desc; /**< Service descriptor */
    rend_service_descriptor_t *parsed; /**< Parsed value of 'desc' */
  } rend_cache_entry_t;
  
  /* Introduction point failure type. */
  typedef struct rend_cache_failure_intro_t {
    /* When this intro point failure occured thus we allocated this object and
     * cache it. */
    time_t created_ts;
    rend_intro_point_failure_t failure_type;
  } rend_cache_failure_intro_t;
  
  /** Cache failure object indexed by service ID. */
  typedef struct rend_cache_failure_t {
    /* Contains rend_cache_failure_intro_t indexed by identity digest. */
    digestmap_t *intro_failures;
  } rend_cache_failure_t;
  
  typedef enum {
    REND_CACHE_TYPE_CLIENT  = 1,
    REND_CACHE_TYPE_SERVICE = 2,
  } rend_cache_type_t;
  
  /* Return maximum lifetime in seconds of a cache entry. */
  static inline time_t
  rend_cache_max_entry_lifetime(void)
  {
    return REND_CACHE_MAX_AGE + REND_CACHE_MAX_SKEW;
  }
  
  void rend_cache_init(void);
  void rend_cache_clean(time_t now, rend_cache_type_t cache_type);
  void rend_cache_failure_clean(time_t now);
  size_t rend_cache_clean_v2_descs_as_dir(time_t cutoff);
  void rend_cache_purge(void);
  void rend_cache_free_all(void);
  int rend_cache_lookup_entry(const char *query, int version,
                              rend_cache_entry_t **entry_out);
  int rend_cache_lookup_v2_desc_as_service(const char *query,
                                           rend_cache_entry_t **entry_out);
  int rend_cache_lookup_v2_desc_as_dir(const char *query, const char **desc);
  
  int rend_cache_store_v2_desc_as_dir(const char *desc);
  int rend_cache_store_v2_desc_as_service(const char *desc);
  int rend_cache_store_v2_desc_as_client(const char *desc,
                                         const char *desc_id_base32,
                                         const rend_data_t *rend_query,
                                         rend_cache_entry_t **entry);
  size_t rend_cache_get_total_allocation(void);
  
  void rend_cache_intro_failure_note(rend_intro_point_failure_t failure,
                                     const uint8_t *identity,
                                     const char *service_id);
  void rend_cache_failure_purge(void);
  void rend_cache_decrement_allocation(size_t n);
  void rend_cache_increment_allocation(size_t n);
  
  #ifdef RENDCACHE_PRIVATE
  
  STATIC size_t rend_cache_entry_allocation(const rend_cache_entry_t *e);
  STATIC void rend_cache_entry_free_(rend_cache_entry_t *e);
  #define rend_cache_entry_free(e) \
    FREE_AND_NULL(rend_cache_entry_t, rend_cache_entry_free_, (e))
  STATIC void rend_cache_failure_intro_entry_free_(rend_cache_failure_intro_t
                                                   *entry);
  #define rend_cache_failure_intro_entry_free(e)                          \
    FREE_AND_NULL(rend_cache_failure_intro_t,                   \
                            rend_cache_failure_intro_entry_free_, (e))
  STATIC void rend_cache_failure_entry_free_(rend_cache_failure_t *entry);
  #define rend_cache_failure_entry_free(e)                        \
    FREE_AND_NULL(rend_cache_failure_t,                 \
                            rend_cache_failure_entry_free_, (e))
  STATIC int cache_failure_intro_lookup(const uint8_t *identity,
                                        const char *service_id,
                                        rend_cache_failure_intro_t
                                        **intro_entry);
  STATIC rend_cache_failure_intro_t *rend_cache_failure_intro_entry_new(
                                        rend_intro_point_failure_t failure);
  STATIC rend_cache_failure_t *rend_cache_failure_entry_new(void);
  STATIC void rend_cache_failure_remove(rend_service_descriptor_t *desc);
  STATIC void cache_failure_intro_add(const uint8_t *identity,
                                      const char *service_id,
                                      rend_intro_point_failure_t failure);
  STATIC void validate_intro_point_failure(const rend_service_descriptor_t *desc,
                                          const char *service_id);
  
  STATIC void rend_cache_failure_entry_free_void(void *entry);
  
  #ifdef TOR_UNIT_TESTS
  extern strmap_t *rend_cache;
  extern strmap_t *rend_cache_failure;
  extern digestmap_t *rend_cache_v2_dir;
  extern size_t rend_cache_total_allocation;
  #endif /* defined(TOR_UNIT_TESTS) */
  #endif /* defined(RENDCACHE_PRIVATE) */
  
  #endif /* !defined(TOR_RENDCACHE_H) */
  
  