src/or/hs_cache.h

   1 /* Copyright (c) 2016-2017, The Tor Project, Inc. */
   2 /* See LICENSE for licensing information */
   3
   4 /**
   5  * \file hs_cache.h
   6  * \brief Header file for hs_cache.c
   7  **/
   8
   9 #ifndef TOR_HS_CACHE_H
  10 #define TOR_HS_CACHE_H
  11
  12 #include <stdint.h>
  13
  14 #include "crypto.h"
  15 #include "crypto_ed25519.h"
  16 #include "hs_common.h"
  17 #include "hs_descriptor.h"
  18 #include "rendcommon.h"
  19 #include "torcert.h"
  20
  21 /* This is the maximum time an introduction point state object can stay in the
  22  * client cache in seconds (2 mins or 120 seconds). */
  23 #define HS_CACHE_CLIENT_INTRO_STATE_MAX_AGE (2 * 60)
  24
  25 /* Introduction point state. */
  26 typedef struct hs_cache_intro_state_t {
  27   /* When this entry was created and put in the cache. */
  28   time_t created_ts;
  29
  30   /* Did it suffered a generic error? */
  31   unsigned int error : 1;
  32
  33   /* Did it timed out? */
  34   unsigned int timed_out : 1;
  35
  36   /* How many times we tried to reached it and it was unreachable. */
  37   uint32_t unreachable_count;
  38 } hs_cache_intro_state_t;
  39
  40 typedef struct hs_cache_client_intro_state_t {
  41   /* Contains hs_cache_intro_state_t object indexed by introduction point
  42    * authentication key. */
  43   digest256map_t *intro_points;
  44 } hs_cache_client_intro_state_t;
  45
  46 /* Descriptor representation on the directory side which is a subset of
  47  * information that the HSDir can decode and serve it. */
  48 typedef struct hs_cache_dir_descriptor_t {
  49   /* This object is indexed using the blinded pubkey located in the plaintext
  50    * data which is populated only once the descriptor has been successfully
  51    * decoded and validated. This simply points to that pubkey. */
  52   const uint8_t *key;
  53
  54   /* When does this entry has been created. Used to expire entries. */
  55   time_t created_ts;
  56
  57   /* Descriptor plaintext information. Obviously, we can't decrypt the
  58    * encrypted part of the descriptor. */
  59   hs_desc_plaintext_data_t *plaintext_data;
  60
  61   /* Encoded descriptor which is basically in text form. It's a NUL terminated
  62    * string thus safe to strlen(). */
  63   char *encoded_desc;
  64 } hs_cache_dir_descriptor_t;
  65
  66 /* Public API */
  67
  68 void hs_cache_init(void);
  69 void hs_cache_free_all(void);
  70 void hs_cache_clean_as_dir(time_t now);
  71 size_t hs_cache_handle_oom(time_t now, size_t min_remove_bytes);
  72
  73 unsigned int hs_cache_get_max_descriptor_size(void);
  74
  75 /* Store and Lookup function. They are version agnostic that is depending on
  76  * the requested version of the descriptor, it will be re-routed to the
  77  * right function. */
  78 int hs_cache_store_as_dir(const char *desc);
  79 int hs_cache_lookup_as_dir(uint32_t version, const char *query,
  80                            const char **desc_out);
  81
  82 const hs_descriptor_t *
  83 hs_cache_lookup_as_client(const ed25519_public_key_t *key);
  84 int hs_cache_store_as_client(const char *desc_str,
  85                              const ed25519_public_key_t *identity_pk);
  86 void hs_cache_clean_as_client(time_t now);
  87
  88 /* Client failure cache. */
  89 void hs_cache_client_intro_state_note(const ed25519_public_key_t *service_pk,
  90                                       const ed25519_public_key_t *auth_key,
  91                                       rend_intro_point_failure_t failure);
  92 const hs_cache_intro_state_t *hs_cache_client_intro_state_find(
  93                                        const ed25519_public_key_t *service_pk,
  94                                        const ed25519_public_key_t *auth_key);
  95 void hs_cache_client_intro_state_clean(time_t now);
  96
  97 #ifdef HS_CACHE_PRIVATE
  98
  99 /** Represents a locally cached HS descriptor on a hidden service client. */
 100 typedef struct hs_cache_client_descriptor_t {
 101   /* This object is indexed using the service identity public key */
 102   ed25519_public_key_t key;
 103
 104   /* When was this entry created. Used to expire entries. */
 105   time_t created_ts;
 106
 107   /* The cached descriptor, this object is the owner. It can't be NULL. A
 108    * cache object without a valid descriptor is not possible. */
 109   hs_descriptor_t *desc;
 110
 111   /* Encoded descriptor in string form. Can't be NULL. */
 112   char *encoded_desc;
 113 } hs_cache_client_descriptor_t;
 114
 115 STATIC size_t cache_clean_v3_as_dir(time_t now, time_t global_cutoff);
 116
 117 STATIC hs_cache_client_descriptor_t *
 118 lookup_v3_desc_as_client(const uint8_t *key);
 119
 120 #endif /* HS_CACHE_PRIVATE */
 121
 122 #endif /* TOR_HS_CACHE_H */
 123