src/feature/hs/hs_cell.h

   1 /* Copyright (c) 2017-2019, The Tor Project, Inc. */
   2 /* See LICENSE for licensing information */
   3
   4 /**
   5  * \file hs_cell.h
   6  * \brief Header file containing cell data for the whole HS subsytem.
   7  **/
   8
   9 #ifndef TOR_HS_CELL_H
  10 #define TOR_HS_CELL_H
  11
  12 #include "core/or/or.h"
  13 #include "feature/hs/hs_service.h"
  14
  15 /* An INTRODUCE1 cell requires at least this amount of bytes (see section
  16  * 3.2.2 of the specification). Below this value, the cell must be padded. */
  17 #define HS_CELL_INTRODUCE1_MIN_SIZE 246
  18
  19 /* Status code of an INTRODUCE_ACK cell. */
  20 typedef enum {
  21   HS_CELL_INTRO_ACK_SUCCESS = 0x0000, /* Cell relayed to service. */
  22   HS_CELL_INTRO_ACK_FAILURE = 0x0001, /* Service ID not recognized */
  23   HS_CELL_INTRO_ACK_BADFMT  = 0x0002, /* Bad message format */
  24   HS_CELL_INTRO_ACK_NORELAY = 0x0003, /* Can't relay cell to service */
  25 } hs_cell_introd_ack_status_t;
  26
  27 /* Onion key type found in the INTRODUCE1 cell. */
  28 typedef enum {
  29   HS_CELL_ONION_KEY_TYPE_NTOR = 1,
  30 } hs_cell_onion_key_type_t;
  31
  32 /* This data structure contains data that we need to build an INTRODUCE1 cell
  33  * used by the INTRODUCE1 build function. */
  34 typedef struct hs_cell_introduce1_data_t {
  35   /* Is this a legacy introduction point? */
  36   unsigned int is_legacy : 1;
  37   /* (Legacy only) The encryption key for a legacy intro point. Only set if
  38    * is_legacy is true. */
  39   const crypto_pk_t *legacy_key;
  40   /* Introduction point authentication public key. */
  41   const ed25519_public_key_t *auth_pk;
  42   /* Introduction point encryption public key. */
  43   const curve25519_public_key_t *enc_pk;
  44   /* Subcredentials of the service. */
  45   const uint8_t *subcredential;
  46   /* Onion public key for the ntor handshake. */
  47   const curve25519_public_key_t *onion_pk;
  48   /* Rendezvous cookie. */
  49   const uint8_t *rendezvous_cookie;
  50   /* Public key put before the encrypted data (CLIENT_PK). */
  51   const curve25519_keypair_t *client_kp;
  52   /* Rendezvous point link specifiers. */
  53   smartlist_t *link_specifiers;
  54 } hs_cell_introduce1_data_t;
  55
  56 /* This data structure contains data that we need to parse an INTRODUCE2 cell
  57  * which is used by the INTRODUCE2 cell parsing function. On a successful
  58  * parsing, the onion_pk and rendezvous_cookie will be populated with the
  59  * computed key material from the cell data. This structure is only used during
  60  * INTRO2 parsing and discarded after that. */
  61 typedef struct hs_cell_introduce2_data_t {
  62   /*** Immutable Section: Set on structure init. ***/
  63
  64   /* Introduction point authentication public key. Pointer owned by the
  65      introduction point object through which we received the INTRO2 cell. */
  66   const ed25519_public_key_t *auth_pk;
  67   /* Introduction point encryption keypair for the ntor handshake. Pointer
  68      owned by the introduction point object through which we received the
  69      INTRO2 cell*/
  70   const curve25519_keypair_t *enc_kp;
  71   /* Subcredentials of the service. Pointer owned by the descriptor that owns
  72      the introduction point through which we received the INTRO2 cell. */
  73   const uint8_t *subcredential;
  74   /* Payload of the received encoded cell. */
  75   const uint8_t *payload;
  76   /* Size of the payload of the received encoded cell. */
  77   size_t payload_len;
  78
  79   /*** Mutable Section: Set upon parsing INTRODUCE2 cell. ***/
  80
  81   /* Onion public key computed using the INTRODUCE2 encrypted section. */
  82   curve25519_public_key_t onion_pk;
  83   /* Rendezvous cookie taken from the INTRODUCE2 encrypted section. */
  84   uint8_t rendezvous_cookie[REND_COOKIE_LEN];
  85   /* Client public key from the INTRODUCE2 encrypted section. */
  86   curve25519_public_key_t client_pk;
  87   /* Link specifiers of the rendezvous point. Contains link_specifier_t. */
  88   smartlist_t *link_specifiers;
  89   /* Replay cache of the introduction point. */
  90   replaycache_t *replay_cache;
  91 } hs_cell_introduce2_data_t;
  92
  93 /* Build cell API. */
  94 ssize_t hs_cell_build_establish_intro(const char *circ_nonce,
  95                                       const hs_service_intro_point_t *ip,
  96                                       uint8_t *cell_out);
  97 ssize_t hs_cell_build_rendezvous1(const uint8_t *rendezvous_cookie,
  98                                   size_t rendezvous_cookie_len,
  99                                   const uint8_t *rendezvous_handshake_info,
 100                                   size_t rendezvous_handshake_info_len,
 101                                   uint8_t *cell_out);
 102 ssize_t hs_cell_build_introduce1(const hs_cell_introduce1_data_t *data,
 103                                  uint8_t *cell_out);
 104 ssize_t hs_cell_build_establish_rendezvous(const uint8_t *rendezvous_cookie,
 105                                            uint8_t *cell_out);
 106
 107 /* Parse cell API. */
 108 ssize_t hs_cell_parse_intro_established(const uint8_t *payload,
 109                                         size_t payload_len);
 110 ssize_t hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data,
 111                                  const origin_circuit_t *circ,
 112                                  const hs_service_t *service);
 113 int hs_cell_parse_introduce_ack(const uint8_t *payload, size_t payload_len);
 114 int hs_cell_parse_rendezvous2(const uint8_t *payload, size_t payload_len,
 115                               uint8_t *handshake_info,
 116                               size_t handshake_info_len);
 117
 118 /* Util API. */
 119 void hs_cell_introduce1_data_clear(hs_cell_introduce1_data_t *data);
 120
 121 #endif /* !defined(TOR_HS_CELL_H) */
 122