src/core/or/crypt_path_st.h

   1 /* Copyright (c) 2001 Matej Pfajfar.
   2  * Copyright (c) 2001-2004, Roger Dingledine.
   3  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   4  * Copyright (c) 2007-2021, The Tor Project, Inc. */
   5 /* See LICENSE for licensing information */
   6
   7 /**
   8  * @file crypt_path_st.h
   9  * @brief Path structures for origin circuits.
  10  **/
  11
  12 #ifndef CRYPT_PATH_ST_H
  13 #define CRYPT_PATH_ST_H
  14
  15 #include "core/or/relay_crypto_st.h"
  16 struct crypto_dh_t;
  17
  18 #define CRYPT_PATH_MAGIC 0x70127012u
  19
  20 struct fast_handshake_state_t;
  21 struct ntor_handshake_state_t;
  22 struct crypto_dh_t;
  23 struct onion_handshake_state_t {
  24   uint16_t tag;
  25   union {
  26     struct fast_handshake_state_t *fast;
  27     struct crypto_dh_t *tap;
  28     struct ntor_handshake_state_t *ntor;
  29   } u;
  30 };
  31
  32 /** Macro to encapsulate private members of a struct.
  33  *
  34  *  Renames 'x' to 'x_crypt_path_private_field'.
  35  */
  36 #define CRYPT_PATH_PRIV_FIELD(x) x ## _crypt_path_private_field
  37
  38 #ifdef CRYPT_PATH_PRIVATE
  39
  40 /* Helper macro to access private members of a struct. */
  41 #define pvt_crypto CRYPT_PATH_PRIV_FIELD(crypto)
  42
  43 #endif /* defined(CRYPT_PATH_PRIVATE) */
  44
  45 /** Holds accounting information for a single step in the layered encryption
  46  * performed by a circuit.  Used only at the client edge of a circuit. */
  47 struct crypt_path_t {
  48   uint32_t magic;
  49
  50   /** Current state of the handshake as performed with the OR at this
  51    * step. */
  52   onion_handshake_state_t handshake_state;
  53   /** Diffie-hellman handshake state for performing an introduction
  54    * operations */
  55   struct crypto_dh_t *rend_dh_handshake_state;
  56
  57   /** Negotiated key material shared with the OR at this step. */
  58   char rend_circ_nonce[DIGEST_LEN];/* KH in tor-spec.txt */
  59
  60   /** Information to extend to the OR at this step. */
  61   extend_info_t *extend_info;
  62
  63   /** Is the circuit built to this step?  Must be one of:
  64    *    - CPATH_STATE_CLOSED (The circuit has not been extended to this step)
  65    *    - CPATH_STATE_AWAITING_KEYS (We have sent an EXTEND/CREATE to this step
  66    *      and not received an EXTENDED/CREATED)
  67    *    - CPATH_STATE_OPEN (The circuit has been extended to this step) */
  68   uint8_t state;
  69 #define CPATH_STATE_CLOSED 0
  70 #define CPATH_STATE_AWAITING_KEYS 1
  71 #define CPATH_STATE_OPEN 2
  72   struct crypt_path_t *next; /**< Link to next crypt_path_t in the circuit.
  73                               * (The list is circular, so the last node
  74                               * links to the first.) */
  75   struct crypt_path_t *prev; /**< Link to previous crypt_path_t in the
  76                               * circuit. */
  77
  78   int package_window; /**< How many cells are we allowed to originate ending
  79                        * at this step? */
  80   int deliver_window; /**< How many cells are we willing to deliver originating
  81                        * at this step? */
  82
  83   /*********************** Private members ****************************/
  84
  85   /** Private member: Cryptographic state used for encrypting and
  86    * authenticating relay cells to and from this hop. */
  87   relay_crypto_t CRYPT_PATH_PRIV_FIELD(crypto);
  88 };
  89
  90 #endif /* !defined(CRYPT_PATH_ST_H) */