or.h

关于tor匿名通信的源代码

  time_t client_used;

  uint32_t real_addr; /**< The actual address that this connection came from
                       * or went to.  The <b>addr</b> field is prone to
                       * getting overridden by the address from the router
                       * descriptor matching <b>identity_digest</b>. */

  circ_id_type_t circ_id_type:2; /**< When we send CREATE cells along this
                                  * connection, which half of the space should
                                  * we use? */
  /** Should this connection be used for extending circuits to the server
   * matching the <b>identity_digest</b> field?  Set to true if we're pretty
   * sure we aren't getting MITMed, either because we're connected to an
   * address listed in a server descriptor, or because an authenticated
   * NETINFO cell listed the address we're connected to as recognized. */
  unsigned int is_canonical:1;
  uint8_t link_proto; /**< What protocol version are we using? 0 for
                       * "none negotiated yet." */
  uint16_t next_circ_id; /**< Which circ_id do we try to use next on
                          * this connection?  This is always in the
                          * range 0..1<<15-1. */

  or_handshake_state_t *handshake_state; /**< If we are setting this connection
                                          * up, state information to do so. */
  time_t timestamp_lastempty; /**< When was the outbuf last completely empty?*/
  time_t timestamp_last_added_nonpadding; /** When did we last add a
                                           * non-padding cell to the outbuf? */

  /* bandwidth* and read_bucket only used by ORs in OPEN state: */
  int bandwidthrate; /**< Bytes/s added to the bucket. (OPEN ORs only.) */
  int bandwidthburst; /**< Max bucket size for this conn. (OPEN ORs only.) */
  int read_bucket; /**< When this hits 0, stop receiving. Every second we
                    * add 'bandwidthrate' to this, capping it at
                    * bandwidthburst. (OPEN ORs only) */
  int n_circuits; /**< How many circuits use this connection as p_conn or
                   * n_conn ? */

  /** Double-linked ring of circuits with queued cells waiting for room to
   * free up on this connection's outbuf.  Every time we pull cells from a
   * circuit, we advance this pointer to the next circuit in the ring. */
  struct circuit_t *active_circuits;
  struct or_connection_t *next_with_same_id; /**< Next connection with same
                                              * identity digest as this one. */
} or_connection_t;

/** Subtype of connection_t for an "edge connection" -- that is, a socks (ap)
 * connection, or an exit. */
typedef struct edge_connection_t {
  connection_t _base;

  struct edge_connection_t *next_stream; /**< Points to the next stream at this
                                          * edge, if any */
  struct crypt_path_t *cpath_layer; /**< A pointer to which node in the circ
                                     * this conn exits at. */
  int package_window; /**< How many more relay cells can I send into the
                       * circuit? */
  int deliver_window; /**< How many more relay cells can end at me? */

  /** Nickname of planned exit node -- used with .exit support. */
  char *chosen_exit_name;

  socks_request_t *socks_request; /**< SOCKS structure describing request (AP
                                   * only.) */
  struct circuit_t *on_circuit; /**< The circuit (if any) that this edge
                                 * connection is using. */

  uint32_t address_ttl; /**< TTL for address-to-addr mapping on exit
                         * connection.  Exit connections only. */

  uint16_t stream_id; /**< The stream ID used for this edge connection on its
                       * circuit */

  /** The reason why this connection is closing; passed to the controller. */
  uint16_t end_reason;

  /** Quasi-global identifier for this connection; used for control.c */
  /* XXXX NM This can get re-used after 2**32 streams */
  uint32_t global_identifier;

  /** Bytes read since last call to control_event_stream_bandwidth_used() */
  uint32_t n_read;

  /** Bytes written since last call to control_event_stream_bandwidth_used() */
  uint32_t n_written;

  /** What rendezvous service are we querying for? (AP only) */
  char rend_query[REND_SERVICE_ID_LEN_BASE32+1];

  /** Number of times we've reassigned this application connection to
   * a new circuit. We keep track because the timeout is longer if we've
   * already retried several times. */
  uint8_t num_socks_retries;

  /** True iff this connection is for a dns request only. */
  unsigned int is_dns_request:1;

  /** True iff this stream must attach to a one-hop circuit (e.g. for
   * begin_dir). */
  unsigned int want_onehop:1;
  /** True iff this stream should use a BEGIN_DIR relay command to establish
   * itself rather than BEGIN (either via onehop or via a whole circuit). */
  unsigned int use_begindir:1;

  /** If this is a DNSPort connection, this field holds the pending DNS
   * request that we're going to try to answer.  */
  struct evdns_server_request *dns_server_request;

} edge_connection_t;

/** Subtype of connection_t for an "directory connection" -- that is, an HTTP
 * connection to retrieve or serve directory material. */
typedef struct dir_connection_t {
  connection_t _base;

  char *requested_resource; /**< Which 'resource' did we ask the directory
                             * for? */
  unsigned int dirconn_direct:1; /**< Is this dirconn direct, or via Tor? */

  /* Used only for server sides of some dir connections, to implement
   * "spooling" of directory material to the outbuf.  Otherwise, we'd have
   * to append everything to the outbuf in one enormous chunk. */
  /** What exactly are we spooling right now? */
  enum {
    DIR_SPOOL_NONE=0, DIR_SPOOL_SERVER_BY_DIGEST, DIR_SPOOL_SERVER_BY_FP,
    DIR_SPOOL_EXTRA_BY_DIGEST, DIR_SPOOL_EXTRA_BY_FP,
    DIR_SPOOL_CACHED_DIR, DIR_SPOOL_NETWORKSTATUS
  } dir_spool_src : 3;
  /** If we're fetching descriptors, what router purpose shall we assign
   * to them? */
  uint8_t router_purpose;
  /** List of fingerprints for networkstatuses or desriptors to be spooled. */
  smartlist_t *fingerprint_stack;
  /** A cached_dir_t object that we're currently spooling out */
  struct cached_dir_t *cached_dir;
  /** The current offset into cached_dir. */
  off_t cached_dir_offset;
  /** The zlib object doing on-the-fly compression for spooled data. */
  tor_zlib_state_t *zlib_state;

  /** What hidden service descriptor are we fetching, if any? */
  int rend_version;

  /** What rendezvous service are we querying for? */
  char rend_query[REND_SERVICE_ID_LEN_BASE32+1];

  char identity_digest[DIGEST_LEN]; /**< Hash of the public RSA key for
                                     * the directory server's signing key. */

} dir_connection_t;

/** Subtype of connection_t for an connection to a controller. */
typedef struct control_connection_t {
  connection_t _base;

  uint32_t event_mask; /**< Bitfield: which events does this controller
                        * care about? */
  unsigned int use_long_names:1; /**< True if we should use long nicknames
                                  * on this (v1) connection. Only settable
                                  * via v1 controllers. */
  /** For control connections only. If set, we send extended info with control
   * events as appropriate. */
  unsigned int use_extended_events:1;

  /** True if we have sent a protocolinfo reply on this connection. */
  unsigned int have_sent_protocolinfo:1;

  uint32_t incoming_cmd_len;
  uint32_t incoming_cmd_cur_len;
  char *incoming_cmd;
  /* Used only by control v0 connections */
  uint16_t incoming_cmd_type;
} control_connection_t;

/** Cast a connection_t subtype pointer to a connection_t **/
#define TO_CONN(c) (&(((c)->_base)))
/** Helper macro: Given a pointer to to._base, of type from*, return &to. */
#define DOWNCAST(to, ptr) ((to*)SUBTYPE_P(ptr, to, _base))

/** Convert a connection_t* to an or_connection_t*; assert if the cast is
 * invalid. */
static or_connection_t *TO_OR_CONN(connection_t *);
/** Convert a connection_t* to a dir_connection_t*; assert if the cast is
 * invalid. */
static dir_connection_t *TO_DIR_CONN(connection_t *);
/** Convert a connection_t* to an edge_connection_t*; assert if the cast is
 * invalid. */
static edge_connection_t *TO_EDGE_CONN(connection_t *);
/** Convert a connection_t* to an control_connection_t*; assert if the cast is
 * invalid. */
static control_connection_t *TO_CONTROL_CONN(connection_t *);

static INLINE or_connection_t *TO_OR_CONN(connection_t *c)
{
  tor_assert(c->magic == OR_CONNECTION_MAGIC);
  return DOWNCAST(or_connection_t, c);
}
static INLINE dir_connection_t *TO_DIR_CONN(connection_t *c)
{
  tor_assert(c->magic == DIR_CONNECTION_MAGIC);
  return DOWNCAST(dir_connection_t, c);
}
static INLINE edge_connection_t *TO_EDGE_CONN(connection_t *c)
{
  tor_assert(c->magic == EDGE_CONNECTION_MAGIC);
  return DOWNCAST(edge_connection_t, c);
}
static INLINE control_connection_t *TO_CONTROL_CONN(connection_t *c)
{
  tor_assert(c->magic == CONTROL_CONNECTION_MAGIC);
  return DOWNCAST(control_connection_t, c);
}

typedef enum {
  ADDR_POLICY_ACCEPT=1,
  ADDR_POLICY_REJECT=2,
} addr_policy_action_t;

/** A reference-counted address policy rule. */
typedef struct addr_policy_t {
  int refcnt; /**< Reference count */
  addr_policy_action_t policy_type:2;/**< What to do when the policy matches.*/
  unsigned int is_private:1; /**< True iff this is the pseudo-address,
                              * "private". */
  unsigned int is_canonical:1; /**< True iff this policy is the canonical
                                * copy (stored in a hash table to avoid
                                * duplication of common policies) */
  maskbits_t maskbits; /**< Accept/reject all addresses <b>a</b> such that the
                 * first <b>maskbits</b> bits of <b>a</b> match
                 * <b>addr</b>. */
  /* XXXX_IP6 make this ipv6-capable */
  uint32_t addr; /**< Base address to accept or reject. */
  uint16_t prt_min; /**< Lowest port number to accept/reject. */
  uint16_t prt_max; /**< Highest port number to accept/reject. */
} addr_policy_t;

/** A cached_dir_t represents a cacheable directory object, along with its
 * compressed form. */
typedef struct cached_dir_t {
  char *dir; /**< Contents of this object */
  char *dir_z; /**< Compressed contents of this object. */
  size_t dir_len; /**< Length of <b>dir</b> */
  size_t dir_z_len; /**< Length of <b>dir_z</b> */
  time_t published; /**< When was this object published */
  int refcnt; /**< Reference count for this cached_dir_t. */
} cached_dir_t;

/** Enum used to remember where a signed_descriptor_t is stored and how to
 * manage the memory for signed_descriptor_body.  */
typedef enum {
  /** The descriptor isn't stored on disk at all: the copy in memory is
   * canonical; the saved_offset field is meaningless. */
  SAVED_NOWHERE=0,
  /** The descriptor is stored in the cached_routers file: the
   * signed_descriptor_body is meaningless; the signed_descriptor_len and
   * saved_offset are used to index into the mmaped cache file. */
  SAVED_IN_CACHE,
  /** The descriptor is stored in the cached_routers.new file: the
   * signed_descriptor_body and saved_offset fields are both set. */
  /* FFFF (We could also mmap the file and grow the mmap as needed, or
   * lazy-load the descriptor text by using seek and read.  We don't, for
   * now.)
   */
  SAVED_IN_JOURNAL
} saved_location_t;

/** Enumeration: what kind of downlaod schedule are we using for a given
 * object? */
typedef enum {
  DL_SCHED_GENERIC = 0,
  DL_SCHED_CONSENSUS = 1,
} download_schedule_t;

/** Information about our plans for retrying downloads for a downloadable
 * object. */
typedef struct download_status_t {
  time_t next_attempt_at; /**< When should we try downloading this descriptor
                           * again? */
  uint8_t n_download_failures; /**< Number of failures trying to download the
                                * most recent descriptor. */
  download_schedule_t schedule : 8;
} download_status_t;

/** The max size we expect router descriptor annotations we create to
 * be. We'll accept larger ones if we see them on disk, but we won't
 * create any that are larger than this. */
#define ROUTER_ANNOTATION_BUF_LEN 256

/** Information need to cache an onion router's descriptor. */
typedef struct signed_descriptor_t {
  /** Pointer to the raw server descriptor, preceded by annotations.  Not
   * necessarily NUL-terminated.  If saved_location is SAVED_IN_CACHE, this
   * pointer is null. */
  char *signed_descriptor_body;
  /** Length of the annotations preceeding the server descriptor. */
  size_t annotations_len;
  /** Length of the server descriptor. */
  size_t signed_descriptor_len;
  /** Digest of the server descriptor, computed as specified in
   * dir-spec.txt. */
  char signed_descriptor_digest[DIGEST_LEN];
  /** Identity digest of the router. */