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   /** One of `ONION_HANDSHAKE_TYPE_*`.  Determines which member of the union
  25    * is accessible. */
  26   uint16_t tag;
  27   union {
  28     struct fast_handshake_state_t *fast;
  29     struct ntor_handshake_state_t *ntor;
  30     struct ntor3_handshake_state_t *ntor3;
  31   } u;
  32 };
  33
  34 struct congestion_control_t;
  35
  36 /** Macro to encapsulate private members of a struct.
  37  *
  38  *  Renames 'x' to 'x_crypt_path_private_field'.
  39  */
  40 #define CRYPT_PATH_PRIV_FIELD(x) x ## _crypt_path_private_field
  41
  42 #ifdef CRYPT_PATH_PRIVATE
  43
  44 /* Helper macro to access private members of a struct. */
  45 #define pvt_crypto CRYPT_PATH_PRIV_FIELD(crypto)
  46
  47 #endif /* defined(CRYPT_PATH_PRIVATE) */
  48
  49 /** Holds accounting information for a single step in the layered encryption
  50  * performed by a circuit.  Used only at the client edge of a circuit. */
  51 struct crypt_path_t {
  52   uint32_t magic;
  53
  54   /** Current state of the handshake as performed with the OR at this
  55    * step. */
  56   onion_handshake_state_t handshake_state;
  57   /** Diffie-hellman handshake state for performing an introduction
  58    * operations */
  59   struct crypto_dh_t *rend_dh_handshake_state;
  60
  61   /** Negotiated key material shared with the OR at this step. */
  62   char rend_circ_nonce[DIGEST_LEN];/* KH in tor-spec.txt */
  63
  64   /** Information to extend to the OR at this step. */
  65   extend_info_t *extend_info;
  66
  67   /** Is the circuit built to this step?  Must be one of:
  68    *    - CPATH_STATE_CLOSED (The circuit has not been extended to this step)
  69    *    - CPATH_STATE_AWAITING_KEYS (We have sent an EXTEND/CREATE to this step
  70    *      and not received an EXTENDED/CREATED)
  71    *    - CPATH_STATE_OPEN (The circuit has been extended to this step) */
  72   uint8_t state;
  73 #define CPATH_STATE_CLOSED 0
  74 #define CPATH_STATE_AWAITING_KEYS 1
  75 #define CPATH_STATE_OPEN 2
  76   struct crypt_path_t *next; /**< Link to next crypt_path_t in the circuit.
  77                               * (The list is circular, so the last node
  78                               * links to the first.) */
  79   struct crypt_path_t *prev; /**< Link to previous crypt_path_t in the
  80                               * circuit. */
  81
  82   int package_window; /**< How many cells are we allowed to originate ending
  83                        * at this step? */
  84   int deliver_window; /**< How many cells are we willing to deliver originating
  85                        * at this step? */
  86
  87   /** Congestion control info */
  88   struct congestion_control_t *ccontrol;
  89
  90   /*********************** Private members ****************************/
  91
  92   /** Private member: Cryptographic state used for encrypting and
  93    * authenticating relay cells to and from this hop. */
  94   relay_crypto_t CRYPT_PATH_PRIV_FIELD(crypto);
  95 };
  96
  97 #endif /* !defined(CRYPT_PATH_ST_H) */