src/core/or/onion.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 onion.h
   9  * \brief Header file for onion.c.
  10  **/
  11
  12 #ifndef TOR_ONION_H
  13 #define TOR_ONION_H
  14
  15 struct create_cell_t;
  16 struct curve25519_keypair_t;
  17 struct curve25519_public_key_t;
  18 #include "lib/crypt_ops/crypto_ed25519.h"
  19
  20 #define MAX_ONIONSKIN_CHALLENGE_LEN 255
  21 #define MAX_ONIONSKIN_REPLY_LEN 255
  22
  23 /** A parsed CREATE, CREATE_FAST, or CREATE2 cell. */
  24 typedef struct create_cell_t {
  25   /** The cell command. One of CREATE{,_FAST,2} */
  26   uint8_t cell_type;
  27   /** One of the ONION_HANDSHAKE_TYPE_* values */
  28   uint16_t handshake_type;
  29   /** The number of bytes used in <b>onionskin</b>. */
  30   uint16_t handshake_len;
  31   /** The client-side message for the circuit creation handshake. */
  32   uint8_t onionskin[CELL_PAYLOAD_SIZE - 4];
  33 } create_cell_t;
  34
  35 /** A parsed CREATED, CREATED_FAST, or CREATED2 cell. */
  36 typedef struct created_cell_t {
  37   /** The cell command. One of CREATED{,_FAST,2} */
  38   uint8_t cell_type;
  39   /** The number of bytes used in <b>reply</b>. */
  40   uint16_t handshake_len;
  41   /** The server-side message for the circuit creation handshake. */
  42   uint8_t reply[CELL_PAYLOAD_SIZE - 2];
  43 } created_cell_t;
  44
  45 /** A parsed RELAY_EXTEND or RELAY_EXTEND2 cell */
  46 typedef struct extend_cell_t {
  47   /** One of RELAY_EXTEND or RELAY_EXTEND2 */
  48   uint8_t cell_type;
  49   /** An IPv4 address and port for the node we're connecting to. */
  50   tor_addr_port_t orport_ipv4;
  51   /** An IPv6 address and port for the node we're connecting to. */
  52   tor_addr_port_t orport_ipv6;
  53   /** Identity fingerprint of the node we're connecting to.*/
  54   uint8_t node_id[DIGEST_LEN];
  55   /** Ed25519 public identity key. Zero if not set. */
  56   struct ed25519_public_key_t ed_pubkey;
  57   /** The "create cell" embedded in this extend cell. Note that unlike the
  58    * create cells we generate ourselves, this create cell can have a handshake
  59    * type we don't recognize. */
  60   create_cell_t create_cell;
  61 } extend_cell_t;
  62
  63 /** A parsed RELAY_EXTEND or RELAY_EXTEND2 cell */
  64 typedef struct extended_cell_t {
  65   /** One of RELAY_EXTENDED or RELAY_EXTENDED2. */
  66   uint8_t cell_type;
  67   /** The "created cell" embedded in this extended cell. */
  68   created_cell_t created_cell;
  69 } extended_cell_t;
  70
  71 void create_cell_init(create_cell_t *cell_out, uint8_t cell_type,
  72                       uint16_t handshake_type, uint16_t handshake_len,
  73                       const uint8_t *onionskin);
  74 int create_cell_parse(create_cell_t *cell_out, const cell_t *cell_in);
  75 int created_cell_parse(created_cell_t *cell_out, const cell_t *cell_in);
  76 MOCK_DECL(int,extend_cell_parse,(extend_cell_t *cell_out,
  77                                  const uint8_t command,
  78                                  const uint8_t *payload_in,
  79                                  size_t payload_len));
  80 int extended_cell_parse(extended_cell_t *cell_out, const uint8_t command,
  81                         const uint8_t *payload_in, size_t payload_len);
  82
  83 int create_cell_format(cell_t *cell_out, const create_cell_t *cell_in);
  84 int create_cell_format_relayed(cell_t *cell_out, const create_cell_t *cell_in);
  85 int created_cell_format(cell_t *cell_out, const created_cell_t *cell_in);
  86 int extend_cell_format(uint8_t *command_out, uint16_t *len_out,
  87                        uint8_t *payload_out, const extend_cell_t *cell_in);
  88 int extended_cell_format(uint8_t *command_out, uint16_t *len_out,
  89                          uint8_t *payload_out, const extended_cell_t *cell_in);
  90
  91 #endif /* !defined(TOR_ONION_H) */